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NTN轴承样本part1


Bearing Units

Technical Data

NTN

TECHNICAL DATA INDEX
Page

1. Construction -------------------------------------------------------------------------------------------------------------------------------- 3 2. Design Features and Advantages ----------------------------------------------------------------------------------------- 4
2.1 Maintenance free type ---------------------------------------------------------------------------------------------------------------------- 4 2.2 Relubricatable type -------------------------------------------------------------------------------------------------------------------------- 4 2.3 Special sealing feature --------------------------------------------------------------------------------------------------------------------- 4 2.4 Secure fitting ---------------------------------------------------------------------------------------------------------------------------------- 5 2.5 Self-aligning ----------------------------------------------------------------------------------------------------------------------------------- 5 2.6 Higher rated load capacity ----------------------------------------------------------------------------------------------------------------- 5 2.7 Light weight yet strong housing ---------------------------------------------------------------------------------------------------------- 5 2.8 Easy mounting -------------------------------------------------------------------------------------------------------------------------------- 5 2.9 Accurate fitting of the housing ------------------------------------------------------------------------------------------------------------ 5 2.10 Bearing replaceability --------------------------------------------------------------------------------------------------------------------- 5

3. Tolerance -------------------------------------------------------------------------------------------------------------------------------------- 6
3.1 Tolerances of ball bearings for the unit ------------------------------------------------------------------------------------------------- 6 3.2 Tolerances of housings --------------------------------------------------------------------------------------------------------------------- 9

4. Basic Load Rating and Life --------------------------------------------------------------------------------------------------- 13
4.1 Bearing life ----------------------------------------------------------------------------------------------------------------------------------4.2 Basic rated life and basic dynamic load rating -------------------------------------------------------------------------------------4.3 Machine applications and requisite life ----------------------------------------------------------------------------------------------4.4 Adjusted life rating factor ----------------------------------------------------------------------------------------------------------------4.5 Basic static load rating -------------------------------------------------------------------------------------------------------------------4.6 Allowable static equivalent load -------------------------------------------------------------------------------------------------------13 13 15 15 16 16 17 17 18 19

5. Loads

------------------------------------------------------------------------------------------------------------------------------------------5.1 Load acting on the bearing -------------------------------------------------------------------------------------------------------------5.2 Equivalent dynamic radial load --------------------------------------------------------------------------------------------------------5.3 Equivalent static radial load -------------------------------------------------------------------------------------------------------------

6. Bearing Internal Clearance ---------------------------------------------------------------------------------------------------- 20
6.1 Bearing internal clearance --------------------------------------------------------------------------------------------------------------- 20 6.2 Internal clearance selection ------------------------------------------------------------------------------------------------------------- 20 6.3 Bearing internal clearance selection standards ------------------------------------------------------------------------------------ 21

7. Lubrication --------------------------------------------------------------------------------------------------------------------------------- 23
7.1 Maximum permissible speed of rotation ---------------------------------------------------------------------------------------------7.2 Replenishment of grease ---------------------------------------------------------------------------------------------------------------7.3 Grease fitting -------------------------------------------------------------------------------------------------------------------------------7.4 Standard location of the grease fitting -----------------------------------------------------------------------------------------------23 24 25 26

8. Shaft Designs ---------------------------------------------------------------------------------------------------------------------------- 27
8.1 Set screw system bearing units -------------------------------------------------------------------------------------------------------- 27 8.2 Eccentric collar system ------------------------------------------------------------------------------------------------------------------- 35 8.3 Adapter system bearing units ----------------------------------------------------------------------------------------------------------- 35

9. Handling of the Bearing Unit ------------------------------------------------------------------------------------------------ 36
9.1 Mounting of the housing -----------------------------------------------------------------------------------------------------------------9.2 Mounting the bearing unit on the shaft ----------------------------------------------------------------------------------------------9.3 Running tests ------------------------------------------------------------------------------------------------------------------------------9.4 Inspection during operation -------------------------------------------------------------------------------------------------------------9.5 Dismounting the bearing unit -----------------------------------------------------------------------------------------------------------9.6 Replacement of the bearing ------------------------------------------------------------------------------------------------------------36 38 43 43 43 43

2

Technical Data

NTN

1. Construction
The NTN bearing unit is a combination of a radial ball bearing, seal, and a housing of high-grade cast iron or pressed steel, which comes in various shapes. The outer surface of the bearing and the internal surface of the housing are spherical, so that the unit is self-aligning. The inside construction of the ball bearing for the unit is such that steel balls and retainers of the same type as in series 62 and 63 of the NTN deep groove ball bearing are used. A duplex seal consisting of a combination of an oilproof synthetic rubber seal and a slinger, unique to NTN, is provided on both sides. Depending on the type, the following methods of fitting to the shaft are employed: (1) The inner ring is fastened onto the shaft in two places by set screws. (2) The inner ring has a tapered bore and is fitted to the shaft by means of an adapter. (3) In the eccentric locking collar system the inner ring is fastened to the shaft by means of eccentric grooves provided at the side of the inner ring and on the collar.

Grease fitting Housing Spherical outer ring

Slinger Special rubber seal

Ball end set screw

Relubricatable bearing unit

Maintenance free bearing unit

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Technical Data

NTN

2. Design Features and Advantages
2.1 Maintenance free type
The NTN Maintenance free bearing unit contains a highgrade lithium-based grease, good for use over a long period, which is ideally suited to sealed-type bearings. Also provided is an excellent sealing device, unique to NTN, which prevents any leakage of grease or penetration of dust and water from outside. It is designed so that the rotation of the shaft causes the sealed-in grease to circulate through the inside space, effectively providing maximum lubrication. The lubrication effect is maintained over a long period with no need for replenishment of grease. To summarize the advantages of the NTN maintenance free bearing unit: (1) As an adequate amount of good quality grease is sealed in at the time of manufacture, there is no need for replenishment. This means savings in terms of time and maintenance costs. (2) Since there is no need for any regreasing facilities, such as piping, a more compact design is possible. (3) The sealed-in design eliminates the possibility of grease leakage, which could lead to stained products. (6) Cases where the number of revolutions is relatively high and the noise problem has to be considered; for example, when the bearing is used with the fan of an air conditioner.

2.3 Special sealing feature
2.3.1 Standard bearing units The sealing device of the ball bearing for the NTN bearing unit is a combination of a heat-resistant and oil-proof synthetic rubber seal and a slinger of an exclusive NTN design. The seal, which is fixed in the outer ring, is steelreinforced, and its lip, in contact with the inner ring, is designed to minimize frictional torque. The slinger is fixed to the inner ring of the bearing with which it rotates. There is a small clearance between its periphery and the outer ring. There are triangular protrusions on the outside face of the slinger and, as the bearing rotates, these protrusions on the slinger create a flow of air outward from the bearing. In this way, the slinger acts as a fan which keeps dust and water away from the bearing. These two types of seals on both sides of the bearing prevent grease leakage, and foreign matter is prevented from entering the bearing from outside. 2.3.2 Bearing units with covers The NTN bearing unit with a cover consists of a standard bearing unit and an outside covering for extra protection against dust. Special consideration has been given to its design with respect to dust-proofing. Sealing devices are provided in both the bearing and the housing, so that units of this type operate satisfactorily even in such adverse environments as flour mills, steel mills, foundries, galvanizing plants and chemical plants, where excessive dust is produced and/or liquids are used. They are also eminently suitable for outdoor environments where dust and rain are inevitable, and in heavy industrial machinery such as construction and transportation equipment.

2.2 Relubricatable type
The NTN relubricatable type bearing unit has an advantage over other simillar units being so designed as to permit regreasing even in the case of misalignment of 2? to the right or left. The hole through which the grease fitting is mounted usually causes structural weakening of the housing. However, as a result of extensive testing, in the NTN bearing unit the hole is positioned so as to minimize this adverse effect. In addition, the regreasing groove has been designed to minimize weakening of the housing. While the NTN maintenance free type bearing unit is satisfactory for use under normal operating conditions indoors, in the following circumstances it is necessary to use the relubricatable type bearing unit: (1) Cases where the temperature of the bearing rises above 100?C, 212?F: *- Normal temperature of up to 200?C, 392?F heatresistant bearing units. (2) Cases where there is excessive dust, but space does not permit using a bearing unit with a cover. (3) Cases where the bearing unit is constantly exposed to splashes of water or any other liquid, but space does not permit using a bearing unit with a cover. (4) Cases in which the humidity is very high, and the machine in which the bearing unit is used is run only intermittently. (5) Cases involving a heavy load of which the Cr/Pr value is about 10 or below, and the speed is 10 rpm or below, or the movement is oscillatory.

Fig. 2.1

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Technical Data

NTN

The rubber seal of the cover contacts with the shaft by its two lips, as shown in Fig. 2.2 and 2.3. By filling the groove between the two lips with grease, an excellent sealing effect is obtained and, at the same time, the contacting portions of the lips are lubricated. Furthermore, the groove is so designed that when the shaft is inclined the rubber seal can move in the radial direction. When bearing units are exposed to splashes of water rather than to dust, a drain hole (5 to 8 mm, 0.2 to 0.3 inches in diameter) is provided at the bottom of the cover, and grease should be applied to the side of the bearing itself instead of into the cover.

2.6 Higher rated load capacity
The bearing used in the unit is of the same internal construction as those in NTN bearing series 62 and 63, and is capable of accommodating axial load as well as radial load, or composite load. The rated load capacity of this bearing is considerably higher than that of the corresponding self-aligning ball bearings used for standard plummer blocks.

2.7 Light weight yet strong housing
Housings for NTN bearing units come in various shapes. They consist of either high-grade cast iron, one-piece casting, or of precision finished pressed steel, the latter being lighter in weight. In either case, they are practically designed to combine lightness with maximum strength.

2.4 Secure fitting
Fastening the bearing to the shaft is effected by tightening the ball-end set screw, situated on the inner ring. This is a unique NTN feature which prevents loosening, even if the bearing is subjected to intense vibrations and shocks.

2.8 Easy mounting
The NTN bearing unit is an integrated unit consisting of a bearing and a housing. As the bearing is prelubricated at manufacture with the correct amount of high-grade lithium base, it can be mounted on the shaft just as it is. It is sufficient to carry out a short test run after mounting.

2.5 Self-aligning
With the NTN bearing unit, the outer surface of the ball bearing and the inner surface of the housing are spherical, thus this bearing unit has self-aligning characteristic. Any misalignment of axis that may arise from poor workmanship on the shaft or errors in fitting will be properly adjusted.

2.9 Accurate fitting of the housing
In order to simplify the fitting of the pillow block and flange type bearing units, the housings are provided with a seat for a dowel pin, which may be utilized as needed.

2.10 Bearing replaceability
The bearing used in the NTN bearing unit is replaceable. In the event of bearing failure, a new bearing can be fitted to the existing housing.

Fig. 2.2 Pressed steel cover

Fig. 2.3 Cast iron cover

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Technical Data

NTN

3. Tolerance
The tolerances of the NTN bearing units are in accordance with the following JIS specifications :
C

3.1 Tolerances of ball bearings for the unit
d

B S D

The tolerances of ball bearings used in the unit are shown in the following tables, 3.1 to 3.4.

Set screw type

Table 3.1 (1) Cylindrical bore (UC, UCS, AS, ASS, UEL, UELS, AEL, AELS) Nominal bore diameter d over mm 10 18 31.750 50.800 80 120 inch 0.3937 0.7087 1.2500 2.0000 3.1496 4.7244 mm 18 31.750 50.800 80 120 180 incl. inch 0.7087 1.2500 2.0000 3.1496 4.7244 7.0866 ?dmp Deviations high 15 6 18 7 21 8 24 9 28 11 33 13 low 0 0 0 0 0 0 0 0 0 0 0 0 Cylindrical bore Bore diameter Vdp Variations max. 10 4 12 5 14 6 16 6 19 7 22 9 Width

Unit:

m/0.0001 inch

?Bs, ?Cs Deviations (reference) high 0 0 0 0 0 0 0 0 0 0 0 0 low 120 47 120 47 120 47 150 59 200 79 250 98

Radial runout Kia (reference) (max) 15 6 18 7 20 8 25 10 30 12 35 14

Note: Symbols ?dmp: Mean bore diameter deviation Vdp: Bore diameter variation ?Bs: Inner ring width deviation ?Cs: Outer ring width deviation

Table 3.1 (2) Cylindrical bore (UR, AR, JEL, REL) Nominal bore diameter d over mm 10 18 31.750 50.800 inch 0.3937 0.7087 1.2500 2.0000 mm 18 31.750 50.800 80 incl. inch 0.7087 1.2500 2.0000 3.1496

Unit:

m/0.0001 inch

Cylindrical bore diameter ?dmp Deviations high 13 5 13 5 13 5 15 6 low 0 0 0 0 0 0 0 0 Vdp Variations max. 6 2 6 2 6 2 8 3

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Technical Data

NTN

Table 3.1 (3) Cylindrical bore (CS) Nominal bore diameter d over mm 10 18 31.75 inch 0.3937 0.7087 1.2500 mm 18 31.75 50.8 incl. inch 0.7087 1.2500 2.0000 ?dmp Deviations high 0 0 0 0 0 0 low 8 3 10 4 12 5 Cylindrical bore Bore diameter Vdp Variations max. 10 4 12 5 14 6 Width

Unit:

m/0.0001 inch

?Bs, ?Cs Deviations (reference) (reference) high 0 0 0 0 0 0 low 120 47 120 47 120 47 max. 15 6 18 7 20 8

Radial runout Kia

Table 3.2 Tapered bore (UK, UKS) Nominal bore diameter d over mm 18 30 50 80 120 inch 0.7087 1.1811 1.9685 3.1496 4.7244 mm 30 50 80 120 180 incl. inch 1.1811 1.9685 3.1496 4.7244 7.0866 ?dmp Deviations high 21 8 25 10 30 12 35 14 40 16 low 0 0 0 0 0 0 0 0 0 0

Unit:

m/0.0001 inch

?d1mp ?dmp max. 21 8 25 10 30 12 35 14 40 16

Vdp1)

d1: Basic diameter at the theoretical large end of the tapered hole 1 B d1=d+ 12 ?dmp: Dimensional difference of the average bore diameter within the flat surface at the theoretical small-end of the tapered hole ?d1mp: Dimensional difference of the average bore diameter within the flat surface at the theoretical large-end of the tapered hole

d ?dmp

2

d1 ?dmp

d1 ?dmp

min. max. 0 0 0 0 0 0 0 0 0 0 13 5 15 6 19 7 25 10 31 12

B Tapered hole having dimensional difference of the average bore diameter within the flat surface

Vdp: Inequality of the bore diameter within the flat surface d B : Nominal width of inner ring : Half of the nominal tapered angle of the tapered hole =2?23'9.4" =2.385 94? =0.041 643rad B
Theoretical tapered hole

2

d1

1) To be applied for all radial flat surfaces of tapered hole. Note: 1. To be applied for tapered holes of 1/12. 2. Symbols of quantity or values

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Technical Data

NTN

Table 3.3 Outer ring Nominal outside diameter D over mm 18 30 50 80 120 150 180 250 inch 0.7087 1.1811 1.9685 3.1496 4.7244 5.9055 7.0866 9.8425 mm 30 50 80 120 150 180 250 315 incl. inch 1.1811 1.9685 3.1496 4.7244 5.9055 7.0866 9.8425 12.4016

Unit:

m/0.0001 inch

Mean outside diameter deviation ?Dm high 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 low 9 4 11 4 13 5 15 6 18 7 25 10 30 12 35 14

Radial runout Kea (reference) max. 15 6 20 8 25 10 35 14 40 16 45 18 50 20 60 24

Note: 1) The low deviation of outside diameter Dm does not apply within the distance of 1/4 the width of the outer ring from the side.

Eccentric locking collar

Eccentric locking collar type

Table 3.4 Eccentric locking collar Nominal bore diameter d over mm 10 36.512 55.562 inch 0.3937 1.4375 2.1875 mm 36.512 55.562 61.912 incl. inch 1.4375 2.1875 2.4375 high 0.250 0.010 0.300 0.012 0.300 0.012 Bore diameter deviation ?ds low 0.025 0.001 0.025 0.001 0.025 0.001 Small bore diameter of eccentric surface deviation ?d2s high 0.3 0.012 0.4 0.016 0.4 0.016 low 0 0 0 0 0 0 Eccentricity deviation ?Hs high 0.1 0.004 0.1 0.004 0.1 0.004 low 0.1 0.004 0.1 0.004 0.1 0.004 high 0.270 0.011 0.330 0.013 0.330 0.013 Collar width deviation ?B2s low 0.270 0.011 0.330 0.013 0.330 0.013

Unit: mm/inch

Collar eccentric surface width deviation ?A1s high 0 0 0 0 0 0 low 0.180 0.007 0.180 0.007 0.220 0.009

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Technical Data

NTN

3.2 Tolerances of housings
Table 3.5 Spherical bore diameter of housings Nominal spherical bore diameter Da over mm 30 50 80 120 180 250 inch 1.1811 1.9685 3.1496 4.7244 7.0866 9.8425 mm 50 80 120 180 250 315 incl. inch 1.9685 3.1496 4.7244 7.0866 9.8425 12.4016 Da
Unit: m/0.0001 inch

Deviations ?Dam Tolerance class J7 high 14 6 18 7 22 9 26 10 30 12 36 14 low 11 4 12 5 13 5 14 6 16 6 16 6

Tolerance class H7 high 25 10 30 12 35 14 40 16 46 18 52 20 low 0 0 0 0 0 0 0 0 0 0 0 0

Note: 1) Symbols ?Dam: Mean spherical bore diameter deviation 2) Dimensional tolerances for spherical bore diameter of housing are classified as H7 for clearance fit, and J7 for intermediate fit.

Table 3.6 Pillow block housings (P, HP, UP, PL) Housing numbers P203 P204 P205 P206 P207 P208 P209 P210 P211 P212 P213 P214 P215 P216 P217 P218

Unit: mm/inch

H Deviations ?Hs UP204 UP205 UP206 UP207 UP208 UP209 UP210 PL204 PL205 PL206 PL207 PL209 PL210 0.15 0.006

P305 P306 P307 P308 P309 P310 P311 P312 P313 P314 P315 P316 P317 P318 P319 P320 P321 P322 P324 P326 P328

PX05 PX06 PX07 PX08 PX09 PX10 PX11 PX12 PX13 PX14 PX15 PX16 PX17 PX18 PX20

HP204 HP205 HP206 HP207 HP208 HP209 HP210

0.2 0.008
S Da

H

0.3 0.012

Note: 1) H is height of the shaft center line. 2) This table can be applied for bearing units with dust covers.

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Technical Data

NTN

Table 3.7 (1) Flange unit housings (F, FU, FC, FS, FL, FLU, FD) Iocation tolerance of bolt hole A2 Deviations ?A2s H3 Deviations FC2 high low ?0.046 ?0.0018 high FS3 low high FCX low

Unit: mm/inch

Housing numbers

Radial runout of spigot joint ?is
(max.)

FD201 F204 FD204 FC204 FL204 F205 F305 FX05 FC205 FS305 FL205 FL305 FD205 F206 F306 FX06 FC206 FS306 FL206 FL306 FD206 F207 F307 FX07 FC207 FS307 FL207 FL307 FD207 F208 F308 FX08 FC208 FS308 FL208 FL308 F209 F309 FX09 FC209 FS309 FL209 FL309 F210 F310 FX10 FC210 FS310 FL210 FL310 F211 F311 FX11 FC211 FS311 FL211 FL311 F212 F312 FX12 FC212 FS312 FL212 FL312 F213 F313 FX13 FC213 FS313 FL213 FL313 F214 F314 FX14 FC214 FS314 FL214 FL314 F215 F315 FX15 FC215 FS315 FL215 FL315 F216 F316 FX16 FC216 FS316 FL216 FL316 F217 F317 FX17 FC217 FS317 FL217 FL317 F218 F318 FX18 FC218 FS318 FL218 FL318 FS319 F319 FL319 FS320 F320 FX20 FL320 F321 F322 F324 F326 F328 FS321 FS322 FS324 FS326 FS328 FL321 FL322 FL324 FL326 FL328 0.7 0.028 0.5 0.020

0 0

0 0

?0.046 ?0.0018

0 0

?0.046 ?0.0018

0 0

?0.054 ?0.0021

0 0

?0.054 ?0.0021

0 0

?0.054 ?0.0021

0.2 0.008

0 0 0 0 ?0.063 ?0.0025 0 0
0 0 ?0.072 ?0.0028

?0.063 ?0.0025 0 0 ?0.063 ?0.0025

0.3 0.012

1 0.039

0.8 0.032

?0.072 ?0.0028 0 0 ?0.072 ?0.0028

0 0

?0.081 ?0.0032

0.4 0.016

0 0

?0.089 ?0.0035

Note: 1) J is the bolt hole's center line dimension, and P,C,D. A2 is distance between the center line of spherical bore diameter of the housing and mounting surfaces, and H3 is outside diameter of the spigot joint. 2) Radial runout of spigot joint is applied for flange units with spigot joints. 3) For FU2 and FLU2 types, tolerances for F2 shall be applied. 4) For FCX and FLX types, tolerances for FX shall be applied. 5) This table can be applied for bearing units with dust covers.

Table 3.7 (2) Flange unit housings (diameter of bolt hole) Nominal bore diameter N Housing type
mm over inch incl. mm inch

Unit: mm/inch

N Deviatiors ?Ns mm 0.2 0.3 inch 0.008 0.012

F, FL, FC, FS, FA, FH, FU, FLU

– 30

– 1.1811

30 40

1.1811 1.614

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Technical Data

NTN

Table 3.8 Flange unit housings (FH, FA, PF, PFL) Housing numbers A2 Deviations ?A2s Housing numbers PF203 PF204 PF205 0.5 0.020 PF206 PF207 PF208 PFL203 PFL204 PFL205 0.8 0.032 PFL206 PFL207 0.4 0.016 J Deviations ?Js

Unit: mm/inch

N Deviations ?Ns

FA204 FA205 FA206 FA207 FA208 FA209 FA210 FA211

0.25 0.010

Note: 1) A2 is distance between the center line of spherical bore diameter of housings. 2) J is the bolt hole's center line dimension.

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Technical Data

NTN

Table 3.9 Take-up unit housings (T) A1 Deviations ?A1s H1 Deviations ?H1s high T204 T205 T206 T207 T208 T209 T210 T211 T212 T213 T214 T215 T216 T217 T305 T306 T307 T308 T309 T310 T311 T312 T313 T314 T315 T316 T317 T318 T319 T320 T321 T322 T324 T326 T328 TX05 TX06 TX07 TX08 TX09 TX10 TX11 TX12 TX13 TX14 TX15 TX16 TX17 0.2 0 0.008 0 low

Unit: mm/inch

Housing numbers

Parallelism of guide

0 0

–0.5 –0.020

0.5 0.020

0.6 0.024 0.3 0 0.012 0

0 0

–0.8 –0.032 0.7 0.028

0.8 0.032

Note: 1) A1 is the width of guide rail grooves. 2) H1 is the maximum span of guide rail grooves. 3) This table can be applied for bearing units with dust covers.

Table 3.10 Cartridge unit housings (C) H Deviations ?Hs Housing numbers high C204 C205 C206 C207 C208 C209 C210 C211 C212 C213 0 0 C2 low –0.030 –0.0012 0 0 –0.035 –0.0014 0 0 –0.035 –0.0014 0.2 0.008 high C3 low high CX low Radial runout of outside surface

Unit: mm/inch

A Deviations ?As

C305 C306 C307 C308 C309 C310 C311 C312 C313 C314 C315 C316 C317 C318 C319 C320 C321 C322 C324 C326 C328

CX05 CX06 CX07 CX08 CX09 CX10 CX11 CX12

0 0

–0.035 –0.0014

0.2 0.008

0 0

–0.040 –0.0016

0 0

–0.040 –0.0016

0 0

–0.040 –0.0016

0.3 0.012 0 0 –0.046 –0.0018

0.3 0.012

0 0 0 0

–0.052 –0.0020 –0.057 –0.0022

0.4 0.016

Note: 1) H is the outside diameter of cartridge housings. 2) A is width of cartridge housings.

12

Technical Data

NTN

4. Basic Load Rating and Life
4.1 Bearing life
Even in bearings operating under normal conditions, the surfaces of the raceway and rolling elements are constantly being subjected to repeated compressive stresses which cause flaking of these surfaces to occur. This flaking is due to material fatigue and will eventually cause the bearings to fail. The effective life of a bearing is usually defined in terms of the total number of revolutions a bearing can undergo before flaking of either the raceway surface or the rolling element surfaces occurs. Other causes of bearing failure are often attributed to problems such as seizing, abrasions, cracking, chipping, gnawing, rust, etc. However, these so called "causes" of bearing failure are usually themselves caused by improper installation, insufficient or improper lubrication, faulty sealing or inaccurate bearing selection. Since the above mentioned "causes" of bearing failure can be avoided by taking the proper precautions, and are not simply caused by material fatigue, they are considered separately from the flaking aspect. Cr L10 Pr where, L10 : Basic rated life 106 revolutions Cr : Basic dynamic rated load, N, lbf Pr : Equivalent dynamic load, N, lbf The basic rated life can also be expressed in terms of hours of operation (revolution), and is calculated as shown in formula (4.2). L10h fh fn Pr 33.3 fn n where, L10h : Basic rated life, h f h : Life factor fn : Speed factor n : Rotational speed, r/min Formula (4.2) can also be expressed as shown in formula (4.5). L10h 106 60n Cr Pr
3 1/3 3

fh Cr

4.2 Basic rated life and basic dynamic load rating
A group of seemingly identical bearings when subjected to identical load and operating conditions will exhibit a wide diversity in their durability. This "life" disparity can be accounted for by the difference in the fatigue of the bearing material itself. This disparity is considered statistically when calculating bearing life, and the basic rated life is defined as follows. The basic rated life is based on a 90% statistical model which is expressed as the total number of revolutions 90% of the bearings, in an identical group of bearings subjected to identical operating conditions, will attain or surpass before flaking due to material fatigue occurs. For bearings operating at fixed constant speeds, the basic rated life (90% reliability) is expressed in the total number of hours of operation. The basic dynamic load rating is an expression of the load capacity of a bearing based on a constant load which the bearing can sustain for one million revolutions (the basic life rating). For radial bearings this rating applies to pure radial loads, and for thrust bearings it refers to pure axial loads. The basic dynamic load ratings given in the bearing tables of this catalog are for bearings constructed of NTN standard bearing materials, using standard manufacturing techniques. Please consult NTN for basic load ratings of bearings constructed of special materials or using special manufacturing techniques. The relationship between the basic rated life, the basic dynamic load rating and the bearing load is given in formula (4.1).

The relation between rotational speed n and speed factor fn as well as the relation between the basic rated life L10h and the life factor fh is shown in Fig. 4.1. When several bearings are incorporated in machines or equipment as complete units, all the bearings in the unit are considered as a whole when computing bearing life (see formula 4.6). The total bearing life of the unit is a life rating based on the viable lifetime of the unit before even one of the bearings fails due to rolling contact fatigue. L 1 1 L
1.1 1

1 L2
1.1

1 Ln
1.1

1/1.1

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Technical Data

NTN

where, L : Total life of the whole bearing assembly h L1, L2 Ln: Rated life of bearings 1, 2, n, h In the case where load and the number of revolutions change at regulated intervals, after finding the rated life L1,L2, , Ln under conditions of n1 , p1 : n2 , p2 : nn , pn; the builtin life Lm can be given by the formula (4.7). 106 L1 60n1 106 L2 60n2 Cr P1 Cr P2
3

n r/min

fn

L10h h
80 000

fn

5.4
5 4.5

60 000 40 000 30 000 20 000

0.082 0.09

60 000 40 000 30 000 20 000

0.10
0.12 0.14

4

15 000
3

10 000
8 000 6 000 4 000 3 000 2 000 0.16 0.18

3 .5

15 000 10 000 8 000 6 000 4 000

3

0.20
0.22 0.24 0.26 0.28 0.30 0.35 0.4

2.5

1 500

1 000

106 Ln 60nn
1

Cr Pn
2

800
3

2
1.9 1.8 1.7 1.6 1.5

600 400
n -1

3 000 2 000 1 500

300 200 150

0.5 0.6 0.7 0.8 0.9

Lm L1 L2 Ln

1.4 1.3 1.2 1.1

100

1 000
900 800 700 600 500 400 300

where, L1,L2, ,Ln: Rated life under condition 1, 2, n, h n1,n2, ,nn: Number of revolutions under condition 1, 2, n, r/min P1,P2, ,Pn: Equivalent load under condition 1, 2, n,N, lbf 1, 2, , n: Ratio of condition 1, 2, n, accounting for the total operating time Lm : Built-in life, h

80 60 40 30 20 15

1.0
0.95 0.90 0.85 0.80 0.75

1.0
1.1 1.2 1.0 1.4

10

1.49

200

0.74

Fig. 4.1 Bearing life rating scale

Table 4.1 Rating life for applications Service classification Machines used occasionally Equipment for short period or intermittent serviceinterruption permissible Machine application Door mechanisms, Garage shutter Household appliances, Electric hand tools, Agricultural machines, Lifting tackles in shops Power-Station auxiliary equipment, Elevators, Conveyors, Deck cranes Life time Ln 500

4 000

8 000

Intermittent service machines-high reliability

8 000

14 000

Machines used for 8 hours a day, but not always in full operation

Ore wagon axles, Important gear units

14 000

20 000

Machines fully used for 8 hours

Blowers, General machinery in shops, Continuous operation cranes Compressors, Pumps Power-station equipment, Water-supply equipment for urban areas, Mine ventilators

20 000

30 000

Machines continuously used for 24 hours a day Machines continuously used for 24 hours a day with maximum reliability

50 000 100 000

60 000 200 000

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Technical Data

NTN

4.3 Machine applications and requisite life
When selecting a bearing, it is essential that the requisite life of the bearing be established in relation to the operating conditions. The requisite life of the bearing is usually determined by the type of machine the bearing is to be used in, and duration of service and operational reliability requirements. A general guide to these requisite life criteria is shown in Table 4.1. When determining bearing size, the fatigue life of the bearing is an important factor; however, besides bearing life, the strength and rigidity of the shaft and housing must also be taken into consideration.

NTN bearings can generally be used up to 120?C. If bearings are operated at a higher temperature, the bearing must be specially heat treated (stabilized) so that inadmissible dimensional change does not occur due to micro-structure change. This special heat treatment might cause the reduction of bearing life because of a hardness change.

Table 4.2 Reliability adjustment factor values a1 Reliability % 90 95 96 97 98 99 Ln L10 L5 L4 L3 L2 L1 Reliability factor a1 1.00 0.62 0.53 0.44 0.33 0.21

4.4 Adjusted life rating factor
The basic bearing life rating (90% reliability factor) can be calculated through the formulas mentioned earlier in Section 4.2. However, in some applications a bearing life factor of over 90% reliability may be required. To meet these requirements, bearing life can be lengthened by the use of specially improved bearing materials or special construction techniques. Moreover, according to elastohydrodynamic lubrication theory, it is clear that the bearing operating conditions (lubrication, temperature, speed, etc.) all exert an effect on bearing life. All these adjustment factors are taken into consideration when calculating bearing life, and using the life adjustment factor as prescribed in ISO 281, the adjusted bearing life can be arrived at. C Lna ?? a1 a2 a3 P
3

4.8

where, Lna : Adjusted life rating in millions of revolutions (106) (adjusted for reliability, material and operating conditions) a1 : Reliability adjustment factor a2 : Material adjustment factor a3 : Operating condition adjustment factor 4.4.1 Life adjustment factor for reliability a1 The values for the reliability adjustment factor a1 (for a reliability factor higher than 90%) can be found in Table 4.2. 4.4.2 Life adjustment factor for material a2 The life of a bearing is affected by the material type and quality as well as the manufacturing process. In this regard, the life is adjusted by the use of an a2 factor. The basic dynamic load ratings listed in the catalog are based on NTN's standard material and process, therefore, the adjustment factor a2 1. When special materials or processes are used the adjustment factor a2 can be larger than 1.

4.4.3 Life adjustment factor a3 for operating conditions The operating conditions life adjustment factor a3 is used to adjust for such conditions as lubrication, operating temperature, and other operation factors which have an effect on bearing life. Generally speaking, when lubricating conditions are satisfactory, the a3 factor has a value of one; and when lubricating conditions are exceptionally favorable, and all other operating conditions are normal, a3 can have a value greater than one. However, when lubricating conditions are particularly unfavorable and the oil film formation on the contact surfaces of the raceway and rolling elements is insufficient, the value of a 3 becomes less than one. This insufficient oil film formation can be caused, for example, by the lubricating oil viscosity being too low for the operating temperature (below 13 mm2/s for ball bearings) ; or by exceptionally low rotational speed (n r/min X dp mm less than 10000). For bearings used under special operating conditions, please consult NTN.

15

Technical Data

NTN

As the operating temperature of the bearing increases, the hardness of the bearing material decreases. Thus, the bearing life correspondingly decreases. The operating temperature adjustment values are shown in Fig. 4.2.

4.6 Allowable static equivalent load
Generally the static equivalent load which can be permitted (see section 5.3) is limited by the basic static rated load as stated in Section 4.5. However, depending on requirements regarding friction and smooth operation, these limits may be greater or lesser than the basic static rated load. In the following formula (4.9) and Table 4.4 the safety factor So can be determined considering the maximum static equivalent load. Co So Po max

1.0
Life adjustment value a3

0.8 0.6 0.4 0.2

where, So Safety factor Co Basic static rated load, N, lbf Po max Maximum static equivalent load, N, lbf
150 200 250 300
Table 4.4 Minimum safety factor values So Operating conditions High rotational accuracy demand Ball bearings 2 1 0.5

100

Operating temperature
Fig. 4.2 Life adjustment value for operating temperature

4.5 Basic static load rating
When stationary rolling bearings are subjected to static loads, they suffer from partial permanent deformation of the contact surfaces at the contact point between the rolling elements and the raceway. The amount of deformity increases as the load increases, and if this increase in load exceeds certain limits, the subsequent smooth operation of the bearing is impaired. It has been found through experience that a permanent deformity of 0.0001 times the diameter of the rolling element, occurring at the most heavily stressed contact point between the raceway and the rolling elements, can be tolerated without any impairment in running efficiency. The basic rated static load refers to a fixed static load limit at which a specified amount of permanent deformation occurs. It applies to pure radial loads for radial bearings. The maximum applied load values for contact stress occurring at the rolling element and raceway contact points are given below. For ball bearings (for bearing unit) : 4200 Mpa.

Normal rotating accuracy demand (Universal application) Slight rotational accuracy deterioration permitted (Low speed, heavy loading, etc.)

Note :1) When vibration and/or shock loads are present, a load factor based on the shock load needs to be included in the Po max value.

16

Technical Data

NTN

5. Loads
5.1 Load acting on the bearing
It is very rare that the load on a bearing can be obtained by a simple calculation. Loads applied to the bearing generally include the weight of the rotating element itself, the load produced by the working of the machine, and the load resulting from transmission of power by the belt and gearwheel. Such loads include the radial load, which works on the bearing at right angles to its axis, and the thrust load, which works on the bearing parallel to its axis. These can work either singly or in combination. In addition, the operation of a machine inevitably produces a varying degree of vibrations and shocks. To take this into account, the theoretical value of a load is multiplied by a safety factor that has been derived from past experience. This is known as the "load factor". Load acting on the bearing Load factor fw where, T : Torque, N m, lbf inch. H : Transmission power, kW n : Number of revolutions, r/min Kt : Transmission force (effective transmission force of belt or chain; tangential force of gearwheel), N, lbf r: effective radius of belt pulley, sprocket wheel or gearwheel, m, inch Accordingly, the load actually applied to the shaft by the transmission force can be obtained by the following formula: Actual load Factor Kt

Different factors are adopted according to the transmission system in use. These will be dealt with in the following paragraphs. Belt transmission When power is transmitted by belt, the effective transmission force working on the belt pulley is calculated by formula (5.2). The term "effective transmission force of the belt" refers to the difference in tension between the tensioned side and the loose side of the belt. Therefore, to obtain the load actually acting on the shaft through the medium of the belt pulley, it is necessary to multiply the effective transmission force by a factor which takes into account the type of belt and the initial tension. This is known as the "belt factor".

Calculated load

Table 5.1 below shows the generally accepted load factors fw which correspond to the degree of shock to which the machine is subjected. 5.1.1 Load applied to the bearing by power transmission The force working on the shaft when power is transmitted by belts, chains or gearwheels is obtained, in general, by the following formula: T 9 550 T Kt r
Table 5.1 Load factors fw Load conditions Little or no shock fw 1 to 1.2

H n

84 500

H n

Examples Machines tools, electric machines, etc. Vehicles, driving mechanism, metal-working machinery, steel-making machines, paper-making machinery, rubber mixing machines, hydraulic equipment, hoists, transportation machinery, power-transmission equipment, woodworking machines, printing machines, etc. Agricultural machines, vibrator screens, ball and tube mills, etc.

Some degree of shock; machines with reciprocating parts

1.2 to 1.5

violent shocks

1.5 to 3

In the case of power transmission by belts, gear wheels, etc., load factors adopted are somewhat different from the above. Factors used for power transmission by belts, gearwheels and chains, respectively, are given in the following sections.

Table 5.2 Belt factors fb Belt type V-belt Timing belt Flat belt (with tension pulley) Flat belt fb 1.5 to 2.0 1.1 to 1.3 2.5 to 3.0 3.0 to 4.0

Note :In cases where the distance between shafts is short, the revolution speed is low, or where operating conditions are severe, the higher fb values should be adopted.

17

Technical Data

NTN

Gear transmission In the case of gear transmissions, the theoretical gear load can be calculated from the transmission force and the type of gear. With spur gears, only a radial load is involved; whereas, with helical gears and bevel gears, an additional axial load is present. The simplest case is that of spur gears. In this instance, the tangential force Kt is obtained from the formula (5.2) and the radial force Ks can be obtained from the following formula: Ks Kt tan where, : is the pressure angle of the gear. Accordingly, the theoretical composite force, Kr, working on the gear is obtained from the following formula:

5.1.2 Distribution of the radial load The load acting on the shaft is distributed to the bearings which support the shaft. In Fig. 5.1, the load is applied to the shaft between two bearings; in Fig. 5.2 the load is applied to the shaft outside the two bearings. In practice, however, most cases are combinations of Fig. 5.1 and 5.2, and the load is usually a composite load, that is to say, a combination of radial and axial loads. Therefore they are calculated by the methods described in the following sections.

l l1 W l2

Therefore, to obtain the radial load actually working on the shaft, the theoretical composite force, as above, is multiplied by a factor in which the accuracy and the degree of precision of the gear is taken into account. This is called the "gear factor" and is represented by the symbol fz. In Table 5.3 is below, fz values for spur wheels are given. The gear factor is essentially almost the same as the previously described load factor, fw. In some cases, however, vibrations and shocks are produced also by the machine of which the gear is a part. Here it is necessary to calculate the actual load working on the gear by further multiplying the gear load, as obtained above, by the load factor shown in Table 5.1, according to the degree of shock.
Table 5.3 Gear factors fz Gear Precision gears (tolerance 0.02 mm 0.0008 inch max., for both pitch and shape) Gears finished by ordinary machining work (tolerance 0.02 to 0.1 mm, 0.0008 to 0.0039 inch for both pitch and shape) fz

;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;

F1 F1= l2 l W F2= l1 l W

Fig. 5.1

l F1 l2 l1 W

;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;

F1=

1.05 to 1.1

l1 l2

;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;

F2 W F2= l l2 W

Fig. 5.2 1.1 to 1.3

Chain transmission When power is transmitted by chain, the effective transmission force working on the sprocket wheel is calculated by formula (5.2). To obtain the load actually working, the effective transmission force must be multiplied by the "chain factor", 1.2 to 1.5.

18

;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;;;; ;;

Kr

√K 2 t

K2 s

Kt

sec

F2

Technical Data

NTN

5.2 Equivalent dynamic radial load
For ball bearings used in the NTN unit, the basic rated dynamic loads Cr mentioned in the table of dimensions are applicable only when the load is purely radial. In practice, however, bearings are usually subjected to a composite load. As the table of dimensions is not directly applicable here, it is necessary to convert the values of the radial and axial loads into a single radial load value that would have an effect on the life of bearing equivalent to that of the actual load applied. This is known as the "equivalent dynamic radial load", and from this the life of the ball bearings for the unit is the calculated. The equivalent dynamic radial load is calculated by the following formula: Pr X Fr Y Fa where, Pr : equivalent dynamic radial load, N, lbf Fr : radial load, N, lbf Fa : axial load, N, lbf X : radial factor Y : axial factor Values of X and Y are shown in Table 5.4 below. With ball bearings for the unit, when only radial load is involved, or when Fa /Fr e (e is a value which is determined by the size of an individual bearing and the load acting thereon), the values of X and Y will be 1 and 0 respectively, resulting in the following equation: Pr Fr

5.3 Equivalent static radial load
In the case of a bearing which is stationary, rotates at a low speed of about 10 rpm, or makes slight oscillating movements, it is necessary to take into account the equivalent static radial load, which is the counterpart of the equivalent dynamic radial load of a rotating bearing. In this case, the following formula is used. Por Xo Fr Yo Fa where, Por: equivalent static radial load, N, lbf Fr : radial load, N, lbf Fa : axial load, N, lbf Xo : static radial factor Yo : static axial factor With the ball bearings for the NTN unit, the values of Xo and Yo are Xo 0.6 Yo 0.5. However when only radial load is involved, or when Fa / Fr e, the following values in used: Xo 1 Yo 0

Accordingly, the following equation holds. Por Fr

Table 5.4 Values of X and Y applying when Fa Fr Fa Cor 0.010 0.020 0.040 0.070 0.10 0.15 0.20 0.30 0.40 0.50 e X 0.18 0.20 0.24 0.27 0.29 0.32 0.35 0.38 0.41 0.44 Fa Fr

e e Y 2.46 2.14 1.83 1.61 1.48 1.35 1.25 1.13 1.05 1.00

0.56

Note: Cor is the basic rated static load. (See the table of dimensions.) When the value of Fa or Fa is not in conformity with those given in Fr Cor Table 5.4 above, find the value by interpolation.

19

Technical Data

NTN

6. Bearing Internal Clearance
6.1 Bearing internal clearance
Bearing internal clearance (initial clearance) is the amount of internal clearance a bearing has before being installed on a shaft or in a housing. As shown in Fig. 6.1, when either the inner ring or the outer ring is fixed and the other ring is free to move, displacement can take place in either an axial or radial direction. This amount of displacement (radially or axially) is termed the internal clearance and, depending on the direction, is called the radial internal clearance or the axial internal clearance. When the internal clearance of a bearing is measured, a slight measurement load is applied to the raceway so the internal clearance may be measured accurately. However, at this time, a slight amount of elastic deformation of the bearing occurs under the measurement load, and the clearance measurement value (measured clearance) is slightly larger than the true clearance. This discrepancy between the true bearing clearance and the increased amount due to the elastic deformation must be compensated for. These compensation values are given in Table 6.1. The internal clearance values for each bearing class are shown in Tables 6.3.

6.2 Internal clearance selection
The internal clearance of a bearing under operating conditions (effective clearance) is usually smaller than the same bearing's initial clearance before being installed and operated. This is due to several factors including bearing fit, the difference in temperature between the inner and outer rings, etc. As a bearing's operating clearance has an effect on bearing life, heat generation, vibration, noise, etc.; care must be taken in selecting the most suitable operating clearance. Effective internal clearance: The internal clearance differential between the initial clearance and the operating (effective) clearance (the amount of clearance reduction caused by interference fits, or clearance variation due to the temperature difference between the inner and outer rings) can be calculated by the following formula:
eff o f t (6.1) where, eff : Effective internal clearance, mm o : Bearing internal clearance, mm f : Reduced amount of clearance due to interference, mm t : Reduced amount of clearance due to temperature differential of inner and outer rings, mm

Radial clearance

Axial clearance

Fig.6.1 Internal clearance

Reduced clearance due to interference: When bearings are installed with interference fits on shafts and in housings, the inner ring will expand and the outer ring will contract; thus reducing the bearings' internal clearance. The amount of expansion or contraction varies depending on the shape of the bearing, the shape of the shaft or housing, dimensions of the respective parts, and the type of materials used. The differential can range from approximately 70% to 90% of the effective interference.
f 0.70 0.90 ?deff where, f : Reduced amount of clearance due to interference, mm ?deff : Effective interference, mm

(6.2)

Table 6.1 Adjustment of radial internal clearance based on measured load Nominal bore diameter d (mm) over 10 18 50 incl. 18 50 200 24.5 49 147 Measuring load (N) C2 3 4 6 4 5 8

Unit :

m

Radial clearance increase CN 4 5 8 C3 4 6 9 C4 4 6 9 C5 4 6 9

Reduced internal clearance due to inner/outer ring temperature difference: During operation, normally the outer ring will be from 5? to 10?C cooler than the inner ring or rotating parts. However, if the cooling effect of the housing is large, the shaft is connected to a heat source, or a heated substance is conducted through the hollow shaft; the temperature difference between the two rings can be even greater. The amount of internal clearance is thus further reduced by the differential expansion of the two rings. t ?T Do (6.3)

20

Technical Data

NTN

where, t : Amount of reduced clearance due to heat differential, mm : Bearing steel linear expansion coefficient 12.5 x 10-6/°C ?T : Inner/outer ring temperature differential, °C Do : Outer ring raceway diameter, mm Outer ring raceway diameter, D o , values can be approximated by using formula 6.4. For ball bearings, Do 0.20 d 4.0D where, d : Bearing bore diameter, mm D : Bearing outside diameter, mm (6.4)

Table 6.2 Examples of applications where bearing clearances other than normal clearance are used Operating conditions Shaft is heated and housing is cooled. Shaft or inner ring is heated. Allows for shaft deflection and fitting errors. Tight-fitted for both inner and outer rings. To reduce noise and vibration when rotating. Appilcations Conveyor of casting machine Annealing pit, Drying pit, Curing pit Disc harrows Combines Large blowers Selected clearance C5

C4 C4 C3 C3

Multi-wing fan of air conditioners

C2

6.3 Bearing internal clearance selection standards
Theoretically, in regard to bearing life, the optimum operating internal clearance for any bearing would be a slight negative clearance after the bearing had reached normal operating temperature. Unfortunately, under actual operating conditions, maintaining such optimum tolerances is often difficult at best. Due to various fluctuating operating conditions this slight minus clearance can quickly become a large minus, greatly lowering the life of the bearing and causing excessive heat to be generated. Therefore, an initial internal clearance which will result in a slightly greater than negative internal operating clearance should be selected. Under normal operating conditions (e.g. normal load, fit, speed, temperature, etc.), a standard internal clearance will give a very satisfactory operating clearance. Table 6.2 lists non-standard clearance recommendations for various applications and operating conditions.

21

Technical Data

NTN

Table 6.3 (1) Cylindrical bore bearings Nominal bore diameter d over mm 10 18 24 30 40 50 65 80 100 120 inch 0.3937 0.7087 0.9449 1.1811 1.5748 1.9685 2.5591 3.1496 3.9370 4.7244 mm 18 24 30 40 50 65 80 100 120 140 incl. inch 0.7087 0.9449 1.1811 1.5748 1.9685 2.5591 3.1496 3.9370 4.7244 5.5118 min. mm 0 0 1 1 1 1 1 1 2 2 inch 0 0 0 0 0 0 0 0 1 1 Radial internal clearance C2 max. mm inch 9 10 11 11 11 15 15 18 20 23 4 4 4 4 4 6 6 7 8 9 min. mm 3 5 5 6 6 8 10 12 15 18 inch 1 2 2 2 2 3 4 5 6 7 CN max. mm 18 20 20 20 23 28 30 36 41 48 inch 7 8 8 8 9 11 12 14 16 19 min. mm 11 13 13 15 18 23 25 30 36 41 inch 4 5 5 6 7 9 10 12 14 16 C3 max. mm 25 28 28 33 36 43 51 58 66 81 inch 10 11 11 13 14 17 20 23 26 32

Unit:

m/0.0001 inch

C4 min. mm 18 20 23 28 30 38 46 53 61 71 inch 7 8 9 11 12 15 18 21 24 28 max. mm 33 36 41 46 51 61 71 84 97 114 inch 13 14 16 18 20 24 28 33 38 45

Note :Heat-resistant bearings with suffix HT2 have C4 clearances.

Table 6.3 (2) Tapered bore bearings Nominal bore diameter d over mm 24 30 40 50 65 80 100 120 inch 0.9449 1.1811 1.5748 1.9685 2.5591 3.1496 3.9370 4.7244 mm 30 40 50 65 80 100 120 140 incl. inch 1.1811 1.5748 1.9685 2.5591 3.1496 3.9370 4.7244 5.5118 min. mm 5 6 6 8 10 12 15 18 inch 2 2 2 3 4 5 6 7 Radial internal clearance C2 max. mm inch 20 20 23 28 30 36 41 48 8 8 9 11 12 14 16 19 min. mm 13 15 18 23 25 30 36 41 inch 5 6 7 9 10 12 14 16 CN max. mm 28 33 36 43 51 58 66 81 inch 11 13 14 17 20 23 26 32 min. mm 23 28 30 38 46 53 61 71 inch 9 11 12 15 18 21 24 28 C3 max. mm 41 46 51 61 71 84 97 114 inch 16 18 20 24 28 33 38 45

Unit:

m/0.0001 inch

C4 min. mm 30 40 45 55 65 75 90 105 inch 12 16 18 22 16 30 35 41 max. mm 53 54 73 90 105 120 140 160 inch 21 25 29 35 41 47 55 63

22

Technical Data

NTN

7. Lubrication
As bearings in NTN bearing units have sufficient highgrade grease sealed in at the time of manufacture, there is no need for replenishment while in use. The amount of grease necessary for lubrication is, in general, very small. With the NTN bearing units, the amount of grease occupies about a half to a third of the space inside the bearing. Problems connected with the lubrication of bearings are the generation of heat and seizures occurring at the sliding parts inside the bearing, in particular at the points where the ball is in contact with the retainer, inner and outer rings. The contact pressure at the points where friction occurs on the retainer is only slightly affected by the load acting on the bearing; the amount of heat generated there is approximately in proportion to the sliding velocity. Therefore, this sliding velocity serves as a yardstick to measure the limit of the rotating speed of the bearing. In the case of a bearing unit, however, there is another large factor that has to be taken into account– the circumferential speed at the part where the seal is in contact. The graph in Fig. 7.1 indicates the maximum speed of rotation permissible, taking into account the aforementioned factors. There are two common methods of locking the bearing unit onto the shaft– the set screw system and the eccentric collar system. However, in both of these systems high-speed operation will cause deformation of the inner ring, which may result in vibration of the bearing. For high-speed operation, therefore, it is recommended that an interference fit or a clearance fit with a near-zero clearance be used, with a shaft of the larger size as shown later in this manual in Fig. 8.1, Fig. 8.6. For standard bearing units with the contact type seal, the maximum speed permissible is 120 000/d. Where a higher speed is required, bearing units with the non-contact type seal, are advised. Please contact NTN regarding the use of the latter type. Additionally, it is necessary that the surface on which the housing is mounted be finished to as a high a degree of accuracy as possible. A regularity of within 0.05mm, 0.002 inch is required.

7.1 Maximum permissible speed of rotation
The maximum speed possible while ensuring the safety and long life of ball bearings used in the unit is limited by their size, the circumferential speed at the point where the seal comes into contact, and the load acting on them. To indicate the maximum speed permissible, it is customary to use the value of dn or dmn (d is the bore of the bearing; dm is the diameter of the pitch circle (I.D.+O.D.) /2; n is the number of revolutions).

7 000

Maximum speed permissible r/min

6 000 5 000 4 000 3 000 2 000 1 000 Diam. series 3 Diam. series 2

04 06 08 10 12 14 16 18 20 22 24 26 28 Nominal bore sizes

Fig.7.1

Table 7.1 Brands of grease used in NTN bearing units Grease Bearing units Thickening agent Standard Heat-resistant Cold-resistant Li soap Li soap Li soap Base oil Mineral oil Silicone oil Silicone oil D1 HT2D1 CT1D1 –15? to +100?C, (+5? to +212?F) Normal temp. to +180?C (356?F) –60?C (-76?F) to normal temp. Symbols Operating temperature range

23

Technical Data

NTN

7.2 Replenishment of grease
7.2.1 Sealed-in grease With NTN bearing units, no relubrication is the general rule. The standard self-lubricating type of bearing units contain high-grade lithium-based grease which, being suitable for long-term use, is ideal for sealed-type bearings. They also feature NTN's unique sealing device. Relubrication, therefore, is unnecessary under most operating conditions. At high temperatures, or where there is exposure to water or excessive dust, the highest quality grease is essential. Therefore, NTN uses its own specially selected brands which are shown in Table 7.1. It is necessary to use the same brand when replenishing grease. 7.2.2 Mixing of different kinds of grease Whether or not different kinds of grease may be mixed usually depends on their thickeners. The commonly used criteria are shown in Table 7.2. Properties which are most
Table 7.2 Mixing properties of grease Soap base Ca Na Al Ba Li
Mixing will not produce any appreciable change of properties. Mixing may produce considerable variations of properties. Mixing will cause a drastic change of properties.

susceptible to influences from mixing are viscosity, dropping point and penetration. Water and heat resisting properties as well as mechanical stability are also lowered. Therefore, when mixing in a grease which is different to that which is already in use, it is essential that the thickener (soap base) and the base oil be of the same group. When relubricating NTN bearing units, it is advisable to use the brands of grease shown in Table 7.1. 7.2.3 Relubrication frequency Relubrication frequency varies with the kind and quality of grease used as well as the operating conditions. Therefore, it is difficult to establish a general rule, but under ordinary operating conditions, it is desirable that grease be replenished before one third (1/3) of its calculated life elapses. It is necessary, however, to take into consideration such factors as hardening of grease in the oil hole, making replenishment impossible; deterioration of grease while operation of the machine is suspended, and so forth. In Table 7.3 below are shown standard relubrication frequencies. Irrespective of the calculated life of the grease, this list takes into consideration such factors as the rotational speed of the bearings, operating temperatures and environmental conditions, with a view to safety. 7.2.4 Re-greasing The performance of a bearing is greatly influenced by the quantity of grease. In order to avoid over-filling, it is advisable to replenish the grease while the machine is in operation. Continue to insert grease until a little oozes out from between the outer ring raceway and the periphery of the slinger, for optimum performance.

Ca

Na

Al

Ba

Li

Table 7.3 Standard relubrication frequencies Type of unit Standard Standard Standard Heat-resistant Heat-resistant Heat-resistant Standard Standard Symbol D1 D1 D1 HT2D1 HT2D1 CT1D1 D1 D1 dn Value (d n) 40 000 and below 70 000 and below 70 000 and below 70 000 and below 70 000 and below 70 000 and below 70 000 and below 70 000 and below Environmental conditions Ordinary Ordinary Ordinary Ordinary Ordinary Ordinary Very dusty Exposed to water splashes Operating temp. ?15 to ?15 to +80 to +100 to +150 to ?60 to ?15 to ?80, +80, +100, +150, +180, +80, +100, , F +176 +176 +212 +302 +356 +176 +212 Relubrication frequency Hours +5 to +5 to +176 to +212 to +302 to ?76 to +5 to 1 500 to 3 000 1 000 to 2 000 500 to 700 300 to 700 100 1 000 to 2 000 100 to 500 30 to 100 Period 6 to 12 mo. 3 to 6 mo. 1 mo. 1 mo. 1 wk. 3 to 6 mo. 1 wk. to 1 mo. 1 day to 1 wk.

?15 to +100,

+5 to +212

24

Technical Data

NTN

7.3 Grease fitting
NTN bearing units are, as a general rule, provided with a grease fitting, as shown in Table 7.4, and a grease gun is used for regreasing. However, button-head and pin types may also be furnished on demand. Grease fitting dimensions and the designation of applicable bearing units are given in Table 7.5.
Cap of fitting

5 67.

L ?

Body of fitting

H B d GA type d GB type

H

B

Table 7.4 Grease fitting types available for bearing units Types of housing Pillow type Flange type Take-up type Hanger type Cartridge type NTN standard grease fitting types GA type GA type GB type GA type GA type

Table 7.5 Grease fitting dimensions and designations of applicable bearing units

NTN GA-!/4-28 UNF GA-PF!/8 GA-PF!/4

d mm !/4-28 UNF G!/8 G!/4 8.5 12 14

H inch 0.335 0.472 0.551 mm 7 10 14

B inch 0.276 0.394 0.551

GB type (67.5°) NTN GB-!/4-28 UNF GB-PF!/8 GB-PF!/4 d H mm inch L mm inch 9.3 0.366 B mm inch 8 10 14 0.315 0.394 0.551

!/4-28 UNF 10.5 0.413 G!/8 G!/4 15

14.2 0.559 13.5 0.531 0.591 13.5 0.531

Nominal screw size d !/4-28 UNF G!/8 G!/4

Series 2 203-209 210-215 216-218

Series X X05-X08 X09-X14 X15-X20

Series 3 305-309 310-315 316-328

Note:Screw size for the cartridge type is !/4 - 28 UNF. That for C310D1 to C328D1 is G !/8 (PF !/8).

25

Technical Data

NTN

7.4 Standard location of the grease fitting
Standard location of grease fitting on the housing for the relubricatable bearing units of each type is illustrated below.

45?
30?

P, PL, PX, S-P, type

C-F type

FL, FLU, FLX, S-FL type

T, TX, S-T type

30?

45?
30?

F, FU, S-F (#204, #205) C-P type FS type C-FL type C-T type

HP type

C-FS type

FH type
30?

C, CX type

UP type

FC, FCX, S-FC type

FA type

M, L, S-M, S-L type

Except (#204, #205) F, FU, FX, S-F type C-FC type HB type C-M, C-L type

26

Technical Data

NTN

8. Shaft Designs
Although the shafts used for NTN bearing units require no particularly high standards of accuracy, it is desirable that, as far as possible, they be free from bends and flaws.

da d

8.1 Set screw system bearing units
With set screw system bearing units, under normal operating conditions the inner ring is usually fitted onto the shaft by means of a clearance fit to ensure convenience of assembly. In this case the values shown in Fig. 8.1 are appropriate dimensional tolerances for the shaft.

Table 8.1 Bearing units with covers (for use with step shafts) and shaft diameters A) Metric series Designation of units 10C-UCP206 10C-UCT208 to 10C-UCT217 10C-UCT305 to 10C-UCT311 15C-UCT312 to 15C-UCT324 20C-UCT326 to 20C-UCT328 d+20 d+15 d+10 d+10 da mm

250 000

m6
dn Value mm n r/min

170 000 130 000 100 000 70 000 40 000 k6 j7 h7 h8 h9 20

On the calculation of the dn value, apply the bore dimension of the metric series in the same group. Example: UCP205-100D1 Bore dimension 25mm n(r/min)

to 10C-UCP218 10C-UCP305 to 10C-UCP311 15C-UCP312 to 15C-UCP324 20C-UCP326 to 20C-UCP328

d

Remarks : Designation of bearing units with blind covers. Example : 10CM-UCP206D1

15

10 7 5 3 1

Cr/ Pr

B) Inch series Designation of units da inch 1!/2 1#/4 1&/8 2 2#/8 2!/2 2#/4 3 3!/8 3#/8 3!/2 3#/4 4 Designation of units ZnCZnCZnCZnCZnCZnCZnCZnCZnCZnCZnCZnCZnCZnC305306307308309310311312313314315316317318da inch 1#/8 1!/2 1#/4 1&/8 2!/8 2#/8 2#/4 3 3!/8 3!/4 3!/2 3#/4 4 4

Fig. 8.1 Dimensional tolerance for the shaft for set screw system bearing units

Step shafts Wherever there is a noticeably large axial load, a step shaft, as shown in Fig. 8.2, should, if practical, be used. For bearing units with covers, it is recommended that the units shown in Table 8.1 be used with shafts of the corresponding diameters, as shown in the same table. The values of the radii of the rounded corners of these shafts are shown in Table 8.2.

ZnCZnCZnCZnCZnCZnCZnCZnCZnCZnCZnCZnCZnC-

206207208209210211212213214215216217218-

Note :Designations for all units differ from the normal numbering system. Example 1 Pillow type : ZnC-UCP206-101D1 ZnCM-UCP206-101D1 Example 2 Flange type : ZnC-UCF206-101D1 ZnC-UCFL206-101D1 Example 3 Take-up type : ZnC-UCT206-101D1 ZnCM-UCT206-101D1 n indicates serial number in designing from 1 onward.

Fig.8.2

27

Technical Data

NTN

As an expedient, there may be provided a bored hole on the shaft as illustrated in Fig. 8.3. In this case it is necessary to ensure the accuracy of the relationship between the positions of the housing of the bearing and of the bored hole on the shaft.

When relief is provided in the axial direction by the use of screwed bolts as above, the dimensional relationships applicable are as shown in Tables 8.3 (a) and 8.3 (b) on the following pages.

Fig.8.4 Fig.8.3

ra

Table 8.2 Radii of the round corners of step shafts Designation of bearings UC201 to UC203 UC204 to UC206 UC207 to UC210 UC211 to UC215 UC216 to UC218 ras max. mm inch 0.6 1 1.5 2 2.5 0.024 0.039 0.059 0.079 0.098 Designation of bearings UC305 to UC306 UC307 to UC309 UC310 to UC311 UC312 to UC316 UC317 to UC324 UC326 to UC328 ras max. mm inch 1.5 2 2.5 2.5 3 4 0.059 0.079 0.098 0.098 0.118 0.157

Fig.8.5 (a)

Relief in the axial direction Where several bearing units are fitted on the shaft, or where there is a great distance between two bearing units, one of the bearings is secured to the shaft as the "fixed-side bearing" and is subjected to both the axial and radial loads. The other is mounted on the shaft as the "free-side bearing" and is subjected only to radial load, compensating for expansion of the shaft due to a rise in temperature or for any errors in the distance between bearings that may have occurred during assembly. If there is no free-side bearing, the bearings will be subjected to an abnormal axial load, which could cause premature breakdown. Although it is desirable to use a cartridge-type bearing unit for the above purpose (Fig. 8.4), the following method is often employed. As illustrated in Fig. 8.5 (a) and (b), a key way is cut in the shaft, to accommodate a special set screw.

Fig.8.5 (b)

28

Technical Data

NTN

D H l l1 d1

h b

Table 8.3 (a) Screwed bolt system A) Metric series, applied to metric bore size. Designation of bearings UC201D1W5 UC202D1W5 UC203D1W5 UC204D1W5 UC205D1W5 UC206D1W5 UC207D1W5 UC208D1W5 UC209D1W5 UC210D1W5 UC211D1W5 UC212D1W5 UC213D1W5 UC214D1W5 UC215D1W5 UC216D1W5 UC217D1W5 UC218D1W5 UC305D1W5 UC306D1W5 UC307D1W5 UC308D1W5 UC309D1W5 UC310D1W5 UC311D1W5 UC312D1W5 UC313D1W5 UC314D1W5 UC315D1W5 UC316D1W5 UC317D1W5 UC318D1W5 UC319D1W5 UC320D1W5 UC321D1W5 UC322D1W5 UC324D1W5 UC326D1W5 UC328D1W5 Key way Width b mm 3.5 3.5 3.5 3.5 3.5 4 4 6 6 6 6 7 7 7 7 7 9 9 4 4 6 7 7 9 9 9 9 9 10 10 12 12 12 14 14 14 14 16 16 Depth h mm 3 4.5 5.5 4.5 5 5.5 5 5.5 6 6 5.5 5.5 5.5 5.5 5 6.5 6.5 6.5 6.5 5 5 6 6.5 7 6.5 6 7 6.5 7.5 7 9 8.5 7.5 8 7 9 7 9.5 8.5 Designation and size of bolts S5W5×0.8×11 S5W5×0.8×11 S5W5×0.8×11 S5W5×0.8×8.5 S5W5×0.8×8.5 S5W6×0.75×10 S5W6×0.75×10 S5W8×1×11.5 S5W8×1×11.5 S5W8×1×11.5 S5W8×1×11.5 S5W10×1.25×13.5 S5W10×1.25×13.5 S5W10×1.25×13.5 S5W10×1.25×13.5 S5W10×1.25×15 S5W12×1.5×16.5 S5W12×1.5×16.5 S5W6×0.75×11.5 S5W6×0.75×11.5 S5W8×1×11.5 S5W10×1.25×13.5 S5W10×1.25×15 S5W12×1.5×16.5 S5W12×1.5×16.5 S5W12×1.5×16.5 S5W12×1.5×18 S5W12×1.5×18 S5W14×1.5×20 S5W14×1.5×20 S5W16×1.5×23 S5W16×1.5×23 S5W16×1.5×23 S5W18×1.5×25 S5W18×1.5×25 S5W18×1.5×29 S5W18×1.5×29 S5W20×1.5×33 S5W20×1.5×33 d1 mm 3.5 3.5 3.5 3.5 3.5 4 4 6 6 6 6 7 7 7 7 7 9 9 4 4 6 7 7 9 9 9 9 9 10 10 12 12 12 14 14 14 14 16 16 l mm 11 11 11 8.5 8.5 10 10 11.5 11.5 11.5 11.5 13.5 13.5 13.5 13.5 15 16.5 16.5 11.5 11.5 11.5 13.5 15 16.5 16.5 16.5 18 18 20 20 23 23 23 25 25 29 29 33 33 l1 mm 5 5 5 5 5 5.9 5.9 5.5 5.5 5.5 5.5 6.5 6.5 6.5 6.5 7 7 7 6 6 5.5 6.5 7 7 7 7 7.5 7.5 8.5 8.5 9 9 9 9.5 9.5 10 10 11 11 D mm 6 6 6 6 6 8 8 10 10 10 10 12 12 12 12 12 14 14 8 8 10 12 12 14 14 14 14 14 17 17 19 19 19 22 22 22 22 24 24 H mm 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 4 3 3 3 3 3 4 4 4 4 4 5 5 6 6 6 7 7 7 7 7 7

Remarks: The tolerance for the width (b) of the key way should preferably be set at the range of 0 to +0.2 mm.

29

Technical Data

NTN

D H l l1 d1

h b

B) Inch series, applied to inch bore size Designation of bearings UC201-008D1W5 UC202-009D1W5 UC202-010D1W5 UC203-011D1W5 UC204-012D1W5 UC205-013D1W5 UC205-014D1W5 UC205-015D1W5 UC205-100D1W5 UC206-101D1W5 UC206-102D1W5 UC206-103D1W5 UC206-104D1W5 UC207-104D1W5 UC207-105D1W5 UC207-106D1W5 UC207-107D1W5 UC208-108D1W5 UC208-109D1W5 UC209-110D1W5 UC209-111D1W5 UC209-112D1W5 UC210-113D1W5 UC210-114D1W5 UC210-115D1W5 UC210-200D1W5 UC211-200D1W5 UC211-201D1W5 UC211-202D1W5 UC211-203D1W5 UC212-204D1W5 UC212-205D1W5 UC212-206D1W5 UC212-207D1W5 UC213-208D1W5 UC213-209D1W5 UC214-210D1W5 UC214-211D1W5 UC214-212D1W5 UC215-213D1W5 UC215-214D1W5 UC215-215D1W5 UC215-300D1W5 UC216-301D1W5 UC216-302D1W5 UC216-303D1W5 UC217-304D1W5 UC217-305D1W5 UC217-307D1W5 UC218-308D1W5 Key way Width b Depth h inch inch 0.138 0.138 0.138 0.138 0.138 0.138 0.138 0.138 0.138 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.354 0.354 0.354 0.354 0.118 0.177 0.177 0.217 0.177 0.197 0.197 0.197 0.197 0.217 0.217 0.217 0.217 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.217 0.217 0.217 0.217 0.197 0.197 0.197 0.197 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.256 0.256 0.256 0.256 0.256 0.256 0.197 Designation and size of bolts S7W4.826×32×10.5 S7W4.826×32×10.5 S7W4.826×32×10.5 S7W4.826×32×10.5 S7W4.826×32×8 S7W4.826×32×8 S7W4.826×32×8 S7W4.826×32×8 S7W4.826×32×8 S7W!/4×28×9.5 S7W!/4×28×9.5 S7W!/4×28×9.5 S7W!/4×28×9.5 S7W!/4×28×9.5 S7W!/4×28×9.5 S7W!/4×28×9.5 S7W!/4×28×9.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×14.5 S7W#/8×24×14.5 S7W#/8×24×14.5 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 d1 inch 0.138 0.138 0.138 0.138 0.138 0.138 0.138 0.138 0.138 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.354 0.354 0.354 0.354 l inch 0.413 0.413 0.413 0.413 0.315 0.315 0.315 0.315 0.315 0.374 0.374 0.374 0.374 0.374 0.374 0.374 0.374 0.413 0.413 0.413 0.413 0.413 0.413 0.413 0.413 0.413 0.413 0.413 0.413 0.413 0.492 0.492 0.492 0.492 0.492 0.492 0.492 0.492 0.492 0.492 0.492 0.492 0.492 0.571 0.571 0.571 0.591 0.591 0.591 0.591 l1 inch 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.205 0.205 0.205 0.205 0.205 0.205 0.205 0.205 0.205 0.205 0.205 0.205 0.205 0.224 0.224 0.224 0.224 0.224 0.224 0.224 0.224 0.224 0.224 0.224 0.224 0.224 0.264 0.264 0.264 0.244 0.244 0.244 0.244 D inch 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 H inch 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.157 0.157 0.157 0.157

Note: The tolerance for the width (b) of the key way should preferably be set at the range of 0 to +0.008 inch.

30

Technical Data

NTN

D H l l1 d1

h b

B) Inch series, applied to inch bore size Designation of bearings UC305-013D1W5 UC305-014D1W5 UC305-015D1W5 UC305-100D1W5 UC306-101D1W5 UC306-102D1W5 UC306-103D1W5 UC307-104D1W5 UC307-105D1W5 UC307-106D1W5 UC307-107D1W5 UC308-108D1W5 UC308-109D1W5 UC309-110D1W5 UC309-111D1W5 UC309-112D1W5 UC310-113D1W5 UC310-114D1W5 UC310-115D1W5 UC311-200D1W5 UC311-201D1W5 UC311-202D1W5 UC311-203D1W5 UC312-204D1W5 UC312-205D1W5 UC312-206D1W5 UC312-207D1W5 UC313-208D1W5 UC313-209D1W5 UC314-210D1W5 UC314-211D1W5 UC314-212D1W5 UC315-213D1W5 UC315-214D1W5 UC315-215D1W5 UC315-300D1W5 UC316-301D1W5 UC316-302D1W5 UC316-303D1W5 UC317-304D1W5 UC317-305D1W5 UC317-307D1W5 UC318-307D1W5 UC318-308D1W5 UC319-310D1W5 UC319-311D1W5 UC319-312D1W5 UC320-314D1W5 UC320-315D1W5 UC320-400D1W5 Key way Width b inch 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.236 0.236 0.236 0.236 0.276 0.276 0.276 0.276 0.276 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.551 0.551 0.551 Depth h inch 0.236 0.236 0.236 0.236 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.236 0.236 0.236 0.256 0.256 0.256 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.276 0.276 0.256 0.256 0.256 0.295 0.295 0.295 0.295 0.276 0.276 0.276 0.354 0.354 0.354 0.276 0.276 0.276 0.276 0.276 0.315 0.315 0.315 Designation and size of bolts S7W!/4×28×11 S7W!/4×28×11 S7W!/4×28×11 S7W!/4×28×11 S7W!/4×28×11 S7W!/4×28×11 S7W!/4×28×11 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W%/16×24×10.5 S7W#/8×24×12.5 S7W#/8×24×12.5 S7W#/8×24×14.5 S7W#/8×24×14.5 S7W#/8×24×14.5 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×15 S7W!/2×20×17.5 S7W!/2×20×17.5 S7W(/16×18×17.5 S7W(/16×18×17.5 S7W(/16×18×17.5 S7W(/16×18×19 S7W(/16×18×19 S7W(/16×18×19 S7W(/16×18×19 S7W%/8×18×19 S7W%/8×18×19 S7W%/8×18×19 S7W%/8×18×21.5 S7W%/8×18×21.5 S7W%/8×18×21.5 S7W%/8×18×21.5 S7W%/8×18×21.5 S7W%/8×18×21.5 S7W%/8×18×21.5 S7W%/8×18×21.5 S7W%/8×18×24 S7W%/8×18×24 S7W%/8×18×24 d1 inch 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.236 0.236 0.236 0.236 0.276 0.276 0.276 0.276 0.276 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.551 0.551 0.551 l inch 0.433 0.433 0.433 0.433 0.433 0.433 0.433 0.413 0.413 0.413 0.413 0.492 0.492 0.571 0.571 0.571 0.591 0.591 0.591 0.591 0.591 0.591 0.591 0.591 0.591 0.591 0.591 0.689 0.689 0.689 0.689 0.689 0.748 0.748 0.748 0.748 0.748 0.748 0.748 0.846 0.846 0.846 0.846 0.846 0.846 0.846 0.846 0.945 0.945 0.945 l1 inch 0.228 0.228 0.228 0.228 0.228 0.228 0.228 0.205 0.205 0.205 0.205 0.224 0.224 0.264 0.264 0.264 0.244 0.244 0.244 0.244 0.244 0.244 0.244 0.244 0.244 0.244 0.244 0.276 0.276 0.276 0.276 0.276 0.335 0.335 0.335 0.335 0.335 0.335 0.335 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 0.354 D inch 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.394 0.394 0.394 0.394 0.472 0.472 0.472 0.472 0.472 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.669 0.669 0.669 0.669 0.669 0.669 0.669 0.748 0.748 0.748 0.748 0.748 0.748 0.748 0.748 0.866 0.866 0.866 H inch 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.118 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.276 0.276 0.276

Note: The tolerance for the width (b) of the Key way should preferably be set at the range of 0 to +0.008 inch.

31

Technical Data

NTN

h b

l g a

Table 8.3 (b) Key bolt system A) Metric series, applied to metric bore size. Designation of bearings UC201D1W6 UC202D1W6 UC203D1W6 UC204D1W6 UC205D1W6 UC206D1W6 UC207D1W6 UC208D1W6 UC209D1W6 UC210D1W6 UC211D1W6 UC212D1W6 UC213D1W6 UC214D1W6 UC215D1W6 UC216D1W6 UC217D1W6 UC218D1W6 UC305D1W6 UC306D1W6 UC307D1W6 UC308D1W6 UC309D1W6 UC310D1W6 UC311D1W6 UC312D1W6 UC313D1W6 UC314D1W6 UC315D1W6 UC316D1W6 UC317D1W6 UC318D1W6 UC319D1W6 UC320D1W6 UC321D1W6 UC322D1W6 UC324D1W6 UC326D1W6 UC328D1W6 Key way Width b mm 6 6 6 7 7 8 8 10 10 10 10 12 12 12 12 12 14 14 8 8 10 12 12 14 14 14 14 14 16 16 18 18 18 20 20 20 20 22 22 Depth h mm 4.5 4.5 4 4.5 4.5 4.5 4.5 5 5 5 5 5.5 5.5 5.5 5.5 5.5 6 6 4.5 4.5 5 5.5 5.5 6.5 6.5 6.5 6.5 6.5 7.5 7.5 8.5 8.5 8.5 10.5 10.5 10.5 10.5 11 11 Designation and size of bolts S6W5×0.8×5-1 S6W5×0.8×5-1 S6W5×0.8×5-1 S6W5×0.8×5 S6W5×0.8×5 S6W6×0.75×6 S6W6×0.75×6 S6W8×1×7 S6W8×1×7 S6W8×1×7 S6W8×1×7 S6W10×1.25×9 S6W10×1.25×9 S6W10×1.25×9 S6W10×1.25×9 S6W10×1.25×9 S6W12×1.5×11 S6W12×1.5×11 S6W6×0.75×6 S6W6×0.75×6 S6W8×1×7 S6W10×1.25×9 S6W10×1.25×9 S6W12×1.5×11 S6W12×1.5×11 S6W12×1.5×11 S6W12×1.5×11 S6W12×1.5×11 S6W14×1.5×13 S6W14×1.5×13 S6W16×1.5×16 S6W16×1.5×16 S6W16×1.5×16 S6W18×1.5×18 S6W18×1.5×18 S6W18×1.5×18 S6W18×1.5×18 S6W20×1.5×25 S6W20×1.5×25 a mm 5.9 5.9 5.9 6.9 6.9 7.9 7.9 9.9 9.9 9.9 9.9 11.9 11.9 11.9 11.9 11.9 13.9 13.9 7.9 7.9 9.9 11.9 11.9 13.9 13.9 13.9 13.9 13.9 15.9 15.9 17.9 17.9 17.9 19.9 19.9 19.9 19.9 21.9 21.9 g mm 3 3 3 3.2 3.2 3.2 3.2 3.6 3.6 3.6 3.6 4 4 4 4 4 4.8 4.8 3.2 3.2 3.6 4 4 4.8 4.8 4.8 4.8 4.8 5.8 5.8 6.5 6.5 6.5 8.5 8.5 8.5 8.5 9.5 9.5 l mm 6 6 6 6 6 7 7 8 8 8 8 10 10 10 10 10 12 12 7 7 8 10 10 12 12 12 12 12 14 14 17 17 17 19 19 19 19 26 26

Note: The tolerance for the width (b) of the key way should preferably be set at the range of 0 to +0.2 mm.

32

Technical Data

NTN

h b

l g a

B) Inch series, applied to inch bore size Designation of bearings UC201-008D1W6 UC202-009D1W6 UC202-010D1W6 UC203-011D1W6 UC204-012D1W6 UC205-013D1W6 UC205-014D1W6 UC205-015D1W6 UC205-100D1W6 UC206-101D1W6 UC206-102D1W6 UC206-103D1W6 UC206-104D1W6 UC207-104D1W6 UC207-105D1W6 UC207-106D1W6 UC207-107D1W6 UC208-108D1W6 UC208-109D1W6 UC209-110D1W6 UC209-111D1W6 UC209-112D1W6 UC210-114D1W6 UC210-113D1W6 UC210-115D1W6 UC210-200D1W6 UC211-200D1W6 UC211-201D1W6 UC211-202D1W6 UC211-203D1W6 UC212-204D1W6 UC212-205D1W6 UC212-206D1W6 UC212-207D1W6 UC213-208D1W6 UC213-209D1W6 UC214-210D1W6 UC214-211D1W6 UC214-212D1W6 UC215-213D1W6 UC215-214D1W6 UC215-215D1W6 UC215-300D1W6 UC216-301D1W6 UC216-302D1W6 UC216-303D1W6 UC217-304D1W6 UC217-305D1W6 UC217-307D1W6 UC218-308D1W6 Key way Width b Depth h inch inch 0.236 0.236 0.236 0.236 0.276 0.276 0.276 0.276 0.276 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.551 0.551 0.551 0.551 0.177 0.177 0.177 0.157 0.177 0.177 0.177 0.177 0.177 0.177 0.177 0.177 0.177 0.177 0.177 0.177 0.177 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.197 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.217 0.236 0.236 0.236 0.236 Designation and size of bolts S7W4.826×32×5-1 S7W4.826×32×5-1 S7W4.826×32×5-1 S7W4.826×32×5-1 S7W4.826×32×5 S7W4.826×32×5 S7W4.826×32×5 S7W4.826×32×5 S7W4.826×32×5 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 a inch 0.232 0.232 0.232 0.232 0.272 0.272 0.272 0.272 0.272 0.311 0.311 0.311 0.311 0.311 0.311 0.311 0.311 0.390 0.390 0.390 0.390 0.390 0.390 0.390 0.390 0.390 0.390 0.390 0.390 0.390 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.469 0.547 0.547 0.547 0.547 g inch 0.118 0.118 0.118 0.118 0.126 0.126 0.126 0.126 0.126 0.126 0.126 0.126 0.126 0.126 0.126 0.126 0.126 0.142 0.142 0.142 0.142 0.142 0.142 0.142 0.142 0.142 0.142 0.142 0.142 0.142 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.157 0.189 0.189 0.189 0.189 l inch 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.236 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.394 0.472 0.472 0.472 0.472

Note :The tolerance for the width (b) of the key way should preferably be set at the range of 0 to +0.008 inch.

33

Technical Data

NTN

h b

l g a

B) Inch series, applied to inch bore size Designation of bearings UC305-013D1W6 UC305-014D1W6 UC305-015D1W6 UC305-100D1W6 UC306-101D1W6 UC306-102D1W6 UC306-103D1W6 UC307-104D1W6 UC307-105D1W6 UC307-106D1W6 UC307-107D1W6 UC308-108D1W6 UC308-109D1W6 UC309-110D1W6 UC309-111D1W6 UC309-112D1W6 UC310-113D1W6 UC310-114D1W6 UC310-115D1W6 UC311-200D1W6 UC311-201D1W6 UC311-202D1W6 UC311-203D1W6 UC312-204D1W6 UC312-205D1W6 UC312-206D1W6 UC312-207D1W6 UC313-208D1W6 UC313-209D1W6 UC314-210D1W6 UC314-211D1W6 UC314-212D1W6 UC315-213D1W6 UC315-214D1W6 UC315-215D1W6 UC315-300D1W6 UC316-301D1W6 UC316-302D1W6 UC316-303D1W6 UC317-304D1W6 UC317-305D1W6 UC317-307D1W6 UC318-307D1W6 UC318-308D1W6 UC319-310D1W6 UC319-311D1W6 UC319-312D1W6 UC320-314D1W6 UC320-315D1W6 UC320-400D1W6 Key way Width b Depth h inch inch 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.394 0.394 0.394 0.394 0.472 0.472 0.472 0.472 0.472 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.630 0.630 0.630 0.630 0.630 0.630 0.630 0.709 0.709 0.709 0.709 0.709 0.709 0.709 0.709 0.787 0.787 0.787 0.177 0.177 0.177 0.177 0.177 0.177 0.177 0.197 0.197 0.197 0.197 0.217 0.217 0.217 0.217 0.217 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.295 0.295 0.295 0.295 0.295 0.295 0.295 0.335 0.335 0.335 0.335 0.335 0.335 0.335 0.335 0.413 0.413 0.413 Designation and size of bolts S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W!/4×28×6 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W%/16×24×7 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W#/8×24×9 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W!/2×20×11 S7W(/16×18×13 S7W(/16×18×13 S7W(/16×18×13 S7W(/16×18×13 S7W(/16×18×13 S7W(/16×18×13 S7W(/16×18×13 S7W%/8×18×16 S7W%/8×18×16 S7W%/8×18×16 S7W%/8×18×16 S7W%/8×18×16 S7W%/8×18×16 S7W%/8×18×16 S7W%/8×18×16 S7W%/8×18×18 S7W%/8×18×18 S7W%/8×18×18 a inch 0.311 0.311 0.311 0.311 0.311 0.311 0.311 0.390 0.390 0.390 0.390 0.469 0.469 0.469 0.469 0.469 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.547 0.626 0.626 0.626 0.626 0.626 0.626 0.626 0.705 0.705 0.705 0.705 0.705 0.705 0.705 0.705 0.783 0.783 0.783 g inch 0.126 0.126 0.126 0.126 0.126 0.126 0.126 0.142 0.142 0.142 0.142 0.157 0.157 0.157 0.157 0.157 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.189 0.228 0.228 0.228 0.228 0.228 0.228 0.228 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.256 0.335 0.335 0.335 l inch 0.276 0.276 0.276 0.276 0.276 0.276 0.276 0.315 0.315 0.315 0.315 0.394 0.394 0.394 0.394 0.394 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.472 0.551 0.551 0.551 0.551 0.551 0.551 0.551 0.669 0.669 0.669 0.669 0.669 0.669 0.669 0.669 0.748 0.748 0.748

Note: The tolerance for the width (b) of the key way should preferably be set at the range of 0 to +0.008 inch.

34

Technical Data

NTN

8.2 Eccentric collar system
As in the case of the set screw system, it is usual under normal operating conditions to fit the inner ring onto the shaft by means of a clearance fit, for ease of assembly.Fig. 8.6 shows the appropriate values of dimensional tolerances for the shaft.

250 000

m6
r/min

170 000 130 000 k6 j7 h7 h8 h9 20

On the calculation of the dn value, apply the bore dimension of the metric series in the same group. Example: UELP205-100D1 Bore dimension 25mm n (r/min)

dn value

mm d

n

100 000 70 000 40 000

15

10 7 5 3 1

Cr/ Pr Fig 8.6 Dimensional tolerances for the shaft eccentric collar system bearing units

8.3 Adapter system bearing units
Since in the case of the adapter system, the bearing unit is fastened onto the shaft by means of a sleeve, for dimensional tolerances for the shaft, h9 is applicable under all operating conditions.

35

Technical Data

NTN

9. Handling of the Bearing Unit
9.1 Mounting of the housing
9.1.1 Pillow block type and flange type Although an advantage of the NTN bearing unit is that it can be fitted easily and will function efficiently on any part of a machine, attention must be paid to the following points in order to ensure its normal service life. 1) The surface on which the housing is mounted must be sufficiently rigid. 2) The surface on which the housing is mounted should be as flat as possible (The housing should set firmly in its position). Deformation of the housing caused by incorrect mounting will in turn cause deformation of the bearing, leading to its premature breakdown. 4) The pillow block type and flange type housings are provided with a seat for a dowel for accurate location. For the use of dowel pins, refer to Table 9.1.

b a

Table 9.1 Recommended dimensions of dowel pins Designation of the housings mm P203 P204 P205 P206 P207 P208 P209 P210 P211 C-P204 C-P205 C-P206 C-P207 C-P208 C-P209 C-P210 C-P211 C-P212 C-P213 C-P214 C-P215 C-P216 C-P217 C-P218 C-P305 C-P306 C-P307 C-P308 C-P309 C-P310 C-P311 C-P312 C-P313 C-P314 C-P315 C-P316 C-P317 C-P318 C-P319 C-P320 C-P321 C-P322 C-P324 C-P326 C-P328 a inch mm b inch Recommended pin diameter inch mm 3 3 3 3 3 5 5 5 5 7 7 7 7 7 10 10 4 4 5 5 5 6 6 6 6 6 8 8 8 8 8 8 8 10 10 12 12 0.118 0.118 0.118 0.118 0.118 0.197 0.197 0.197 0.197 0.276 0.276 0.276 0.276 0.276 0.394 0.394 0.157 0.157 0.197 0.197 0.197 0.236 0.236 0.236 0.236 0.236 0.315 0.315 0.315 0.315 0.315 0.315 0.315 0.394 0.394 0.472 0.472

5.5 0.216 5.5 0.216 5.5 0.216 5.5 0.216 5.5 0.216 7 0.276 7 0.276 7.5 0.295 7.5 0.295 9 9 9 9 10 12 12 8 8 10 10 10 12 12 14 14 14 17 17 17 17 17 17 17 19 19 23 23 0.354 0.354 0.354 0.354 0.394 0.472 0.472 0.315 0.315 0.394 0.394 0.394 0.472 0.472 0.551 0.551 0.551 0.669 0.669 0.669 0.669 0.669 0.669 0.669 0.748 0.748 0.906 0.906

5.5 0.216 5.5 0.216 5.5 0.216 5.5 0.216 5.5 0.216 7 0.276 7 0.276 7.5 0.295 7.5 0.295 9 9 9 9 10 12 12 8 8 10 10 10 12 12 14 14 14 17 17 17 17 17 17 17 19 19 23 23 0.354 0.354 0.354 0.354 0.394 0.472 0.472 0.315 0.315 0.394 0.394 0.394 0.472 0.472 0.551 0.551 0.551 0.669 0.669 0.669 0.669 0.669 0.669 0.669 0.748 0.748 0.906 0.906

Fig. 9.1

P212 P213 P214 P215 P216 P217 P218 P305 P306 P307 P308 P309 P310 P311 P312 P313 P314 P315 P316 P317 P318 P319 P320 P321 P322 P324 P326 P328

3) It is desirable that the angle between the surface on which the housing is mounted and the shaft be maintained to a tolerance of 2?.

2
;;; ;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;; ; ; ;;;;;;;;;;;;;; ; ; ;;;;;;;;;;;;;; ;; ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;; ; ;;;;;;;;;;;;;;;; ; ;;;;;;;;;;;;;;

Fig. 9.2
;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ; ; ; ;; ; ; ; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;; ;;;;;;;;; ; ;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;; ; ; ; ;; ; ; ; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;

90

2

;;; ;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;; ;;;;;;;;;;;; ;;;;;;;;;;;; ;;;;;;;;;;;;;

Fig. 9.3

;;;; ;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;;;;;;;;;;;;; ;; ;;;;;;;;;;;; ;;;;;;;;;;;; ;;;;;;;;;; ;;

36

Technical Data

NTN

a

b

a b b a

Designation of the housings mm F204 F205 F206 F207 F208 F209 F210 F211 F212 F213 F214 F215 F216 F217 F218 F305 F306 F307 F308 F309 F310 F311 F312 F313 F314 F315 F316 F317 F318 F319 F320 F321 F322 F324 F326 F328 C-F204 C-F205 C-F206 C-F207 C-F208 C-F209 C-F210 C-F211 C-F212 C-F213 C-F214 C-F215 C-F216 C-F217 C-F218 C-F305 C-F306 C-F307 C-F308 C-F309 C-F310 C-F311 C-F312 C-F313 C-F314 C-F315 C-F316 C-F317 C-F318 C-F319 C-F320 C-F321 C-F322 C-F324 C-F326 C-F328 33 35 35 38 40 43 49 49 49 52 52 52 55 55 61 35 40 47 48 48 48 51 51 57 61 65 65 70 80 80 80 80 90 90 100 108

a inch 1.229 1.378 1.378 1.496 1.575 1.693 1.929 1.929 1.929 2.047 2.047 2.047 2.165 2.165 2.402 1.378 1.575 1.805 1.890 1.890 1.890 2.008 2.008 2.244 2.402 2.559 2.559 2.756 3.150 3.150 3.150 3.150 3.543 3.543 3.937 4.252 mm 6 6 6 7 8 8 8 8 8 9 9 9 12 12 14 6 6 8 8 8 8 10 10 10

b inch 0.236 0.236 0.236 0.276 0.315 0.315 0.315 0.315 0.315 0.354 0.354 0.354 0.472 0.472 0.551 0.236 0.236 0.315 0.315 0.315 0.315 0.394 0.394 0.394

Recommended pin diameter mm 4 4 4 5 5 5 5 5 5 6 6 6 6 6 6 4 4 5 5 5 5 5 5 6 6 6 6 6 8 8 8 8 8 10 10 10 inch 0.157 0.157 0.157 0.197 0.197 0.197 0.197 0.197 0.197 0.236 0.236 0.236 0.236 0.236 0.236 0.157 0.157 0.197 0.197 0.197 0.197 0.197 0.197 0.236 0.236 0.236 0.236 0.236 0.315 0.315 0.315 0.315 0.315 0.394 0.394 0.394

Designation of the housings mm FL204 FL205 FL206 FL207 FL208 FL209 FL210 FL211 FL212 FL213 FL214 FL215 FL216 FL217 FL218 FL305 FL306 FL307 FL308 FL309 FL310 FL311 FL312 FL313 FL314 FL315 FL316 FL317 FL318 FL319 FL320 FL321 FL322 FL324 FL326 FL328 C-FL204 C-FL205 C-FL206 C-FL207 C-FL208 C-FL209 C-FL210 C-FL211 C-FL212 C-FL213 C-FL214 C-FL215 C-FL216 C-FL217 C-FL218 C-FL305 C-FL306 C-FL307 C-FL308 C-FL309 C-FL310 C-FL311 C-FL312 C-FL313 C-FL314 C-FL315 C-FL316 C-FL317 C-FL318 C-FL319 C-FL320 C-FL321 C-FL322 C-FL324 C-FL326 C-FL328 22 32 33 30 33 38 39 44 54 53 53 55 55 55 55 35 44 43 45 51 55 55 60 59 63 66 72 74 74 80 84 84 84 93 94 102

a inch 0.866 1.260 1.299 1.181 1.299 1.496 1.535 1.732 2.126 2.087 2.087 2.165 2.165 2.165 2.165 1.378 1.732 1.693 1.772 2.008 2.165 2.165 2.363 2.323 2.480 2.598 2.835 2.913 2.913 3.150 3.307 3.307 3.307 3.661 3.701 4.016 mm 10 10 12 14 15 15 16 18 19 18 18 21 21 21 22 9 11 13 15 18 15 15 18 24 24 23 27 29 29 30 30 30 36 38 39 40

b inch 0.394 0.394 0.472 0.551 0.591 0.591 0.630 0.709 0.748 0.709 0.709 0.827 0.827 0.827 0.866 0.354 0.433 0.512 0.591 0.709 0.591 0.591 0.709 0.945 0.945 0.906 1.063 1.142 1.142 1.181 1.181 1.181 1.417 1.496 1.535 1.575

Recommended pin diameter mm 4 4 4 5 5 5 5 5 5 6 6 6 6 6 6 4 4 5 5 5 5 5 5 6 6 6 6 6 8 8 8 8 8 10 10 10 inch 0.157 0.157 0.157 0.197 0.197 0.197 0.197 0.197 0.197 0.236 0.236 0.236 0.236 0.236 0.236 0.157 0.157 0.197 0.197 0.197 0.197 0.197 0.197 0.236 0.236 0.236 0.236 0.236 0.315 0.315 0.315 0.315 0.315 0.394 0.394 0.394

10 0.394 8.5 0.335 8.5 0.335 9 10 10 10 10 10 13 13 13 0.354 0.394 0.394 0.394 0.394 0.394 0.512 0.512 0.512

37

Technical Data

NTN

9.1.2 Cartridge type The inside diameter of the housing into which a cartridge type unit is inserted should be H7 under general operating conditions. It should be so furnished as to permit the bearing unit to move freely in the axial direction.

2) Holding the unit at right angles to the shaft, insert the shaft into the bore of the bearing without twisting the bearing. Take care not to strike the slinger nor to subject the unit to any shock (Fig. 9.6).

9.2 Mounting the bearing unit on the shaft
9.2.1 Mounting of the set screw system unit To mount the set screw system bearing unit on the shaft, it is sufficient to tighten the two set screws uniformly. The construction of the NTN "Ball-End Set Screw" is illustrated in Fig. 9.4 with the pin design that prevents it from becoming loose even when it is subjected to vibrations or impact loads. If the fit clearance between the inner ring and the shaft is very small, it is advisable, prior to fastening on the screw, to file off that part of the shaft at which the end of the set screw (ball) strikes, by approximately 0.2 to 0.5mm 0.01 to 0.02 inches, to flatten it , as illustrated in Fig. 9.5. This will facilitate dismounting of the bearing from the shaft should it become necessary. The method of mounting the unit on the shaft is as follows: 1) Make certain that the end of the set screw is not protruding into the bore of the bearing.

Fig. 9.6

3) Insert a hexagonal bar wrench securely into the hexagonal hole of the set screw, and tighten the two screws uniformly. Use the tightening torque shown in Table 9.2.

Ball

Fig. 9.4

Fig. 9.7

4) Mount the housing securely in position on the machine. Sometimes the order of steps 3) and 4) is reversed.
Fig. 9.5

38

Technical Data

NTN

Table 9.2 Recommended torques for tightening set screws A) Metric series, applied to metric bore size. Designation of the bearings of applicable units UC201 to UC205 UC305 to UC306 UCX05 UC208 to UC210 UC211 UCX06 to UCX08 UCX09 UC213 to UC215 UC216 UCX10 UCX11 to UCX12 UC217 to UC218 UCX13 to UCX15 UCX16 to UCX17 UCX18 UCX20 UC315 to UC316 UC317 to UC319 UC320 to UC324 UC326 to UC328 UC310 to UC314 UC308 to UC309 UC307 Designation of set screws M 5×0.8 × 7 M 6×0.75× 8 M 6×0.75× 8 M 8×1 M 8×1 ×10 ×10 Tightening torques N (max.) 3.9 4.9 5.8 7.8 9.8 16.6 19.6 22.5 24.5 29.4 34.3 34.3 53.9 58.8 78.4

B) Inch series, applied to inch bore size. Designation of the bearings for the unit to which torques given are applicable UC201 to UC205 UC305 to UC306 UCX05 UC208 to UC210 UC211 UCX06 to UCX08 UCX09 UC213 to UC215 UC216 UCX10 UCX11 to UCX12 UC217 to UC218 UCX13 to UCX15 UCX16 to UCX17 UCX18 UCX20 UC315 to UC316 UC317 to UC319 UC320 UC310 to UC314 UC308 to UC309 UC307 Designation of set screws No.10-32UNF !/4-28UNF !/4-28UNF %/16-24UNF %/16-24UNF #/8-24UNF #/8-24UNF #/8-24UNF #/8-24UNF !/2-20UNF !/2-20UNF (/16-18UNF %/8-18UNF %/8-18UNF Tightening torques lbf inch (max.) 34 43 52 69 86 147 173 199 216 260 303 303 477 520

M10×1.25×12 M10×1.25×12 M10×1.25×12 M10×1.25×12 M12×1.5 ×13 M12×1.5 ×13 M14×1.5 ×15 M16×1.5 ×18 M18×1.5 ×20 M20×1.5 ×25

Designation of the bearings of applicable units AS201 to 205 AS206 AS207 AS208

Designation of set screws M5×0.8 × 7 M6×0.75× 8 M6×0.75× 8 M8×1 ×10

Tightening torques N (max.) 3.4 4.4 4.9 6.8

Designation of the bearings for the unit to which torques given are applicable AS201 to 205 AS206 AS207 AS208

Designation of set screws No.10-32UNF !/4-28UNF !/4-28UNF %/16-24UNF

Tightening torques lbf inch (max.) 30 39 43 60

39

Technical Data

NTN

9.2.2 Mounting the eccentric locking collar system unit In this system, unlike the screw system, the shaft and inner ring are fastened together by fastening the eccentric collar in the direction of the rotation of the shaft. They are fastened together securely, and deformation of the inner ring seldom occurs. This system, however, is not recommended for applications where the direction of rotation is sometimes reversed. Directions for mounting the unit are as follows : 1) Make certain that the frame in which the housing is to be mounted is suitable to the operating conditions with regard to rigidity, flatness, etc. 2) Make sure that the end of the shaft is not burred and that the end of the set screw in the eccentric collar is not protruding from the interior surface of the collar (Fig. 9.8).

5) Fit the eccentric circular ridge provided on the inner ring into the eccentric circular groove of the eccentric collar, and then provisionally tighten by turning the collar by hand in the direction of the shaft (Fig. 9.10).

Fig. 9.10

6) Insert a bar into the hole provided on the periphery of the eccentric collar and tap the bar so that the collar turns in the direction of rotation of the shaft (see Fig. 9.11).

Fig. 9.8

3) Mount the housing of the unit securely onto the frame. 4) Determine the relative position of the unit and the shaft accurately so that the unit will not be subjected to any thrust, and then insert the eccentric collar (Fig. 9.9).

Fig. 9.11

7) Fasten the set screw of the eccentric collar onto the shaft. Recommended tightening torques are given in Table 9.3.

Fig. 9.9

40

Technical Data

NTN

Table 9.3 Recommended torques for tightening set screws of the eccentric collar A) Metric series, applied to metric bore size. Designation of the bearings of applicable units UEL204 to AEL201 to AEL205 UEL205 UEL303 to UEL206 UEL307 UEL207 AEL206 AEL207 Designation of set screws M 6×0.75× 8 M 8×1 ×10 Tightening torques N m (max.) 7.8 9.8 11.7 15.6 19.6 29.4 34.3 53.9 78.4

M10×1.25×12 M10×1.25×12 M10×1.25×12 M10×1.25×12 M12×1.5 ×13 M16×1.5 ×18 M20×1.5 ×25

UEL208 to AEL208 UEL210 UEL211 UEL308 to UEL212 to UEL312 UEL21 UEL313 to UEL314 UEL315 to UEL317 UEL318 to UEL320

9.2.3 Mounting of the adapter system unit When an adapter system unit is used, there is no danger of the fit between the shaft and the inner ring working loose even if it is subjected to impact loads or vibration. Furthermore, straight shafts of h9 may be used under any operating conditions, except where there is a large axial load. To mount the adapter system unit onto the shaft, the procedure is as follows: 1) Adjust the position of the sleeve so that the tapered part comes to about the center of the bearing. To facilitate the mounting of the sleeve onto the shaft, the opening in the sleeve can be widened using a screwdriver or similar implement. The sleeve should be positioned so that the nut is located on the opposite side from the pulley, etc., for easier handling (Fig. 9.12).

B) Inch series, applied to inch bore size. Designation of the bearings for the unit to which torques given are applicable UEL204 to AEL201 to AEL205 UEL205 UEL303 to UEL206 UEL307 UEL207 UEL208 to UEL210 UEL211 UEL308 to UEL212 to UEL21 UEL312 UEL313 to UEL314 UEL315 to UEL317 UEL318 to UEL328 AEL206 AEL207 Designation of set screws !/4-28UNF %/16-24UNF #/8-24UNF #/8-24UNF #/8-24UNF #/8-24UNF !/2-20UNF %/8-18UNF #/4-16UNF Tightening torques lbf inch (max.)

Shaft

Sleeve

Fig. 9.12
69 86 104 138 173 260 350 520 700

2) Place the bearing unit with the tapered bore properly oriented on the sleeve and abut a cylindrical sleeve against the lock nut side face of the inner ring. Tap the adapter sleeve lightly over its entire periphery, as shown in Fig. 9.13, until a positive contact is made between the bearing and the sleeve.

Fig. 9.13

41

Technical Data

NTN

3) Insert the washer and tighten the nut fully by hand. 4) Apply a jig (or screwdriver where no jig is available) to the notch of the nut and tap it with a hammer. Stop tapping after the nut has turned through from 60? to 90?. Be careful not to strike the slinger. Care should also be taken not to over-tighten the nut, as this will deform the inner ring, causing heat generation and seizure. 5) Bend up the tab on the rim of the washer, which is in line with the notch of the nut. This will prevent the nut from turning. The nut must not be turned backwards to bring the notch into line with the tab on the washer. 6) Mount the housing securely in position on the machine. 9.2.4 Mounting covered bearing units For selection of the shaft, mounting the bearing onto the shaft and fitting the housing follow the same procedure as for standard bearing units. Furthermore, fitting the cover presents no special difficulty, with no need for special tools or jigs. The procedure for mounting covered bearing units is as follows: 1) Remove the cover from the bearing unit. The steel cover can usually be removed easily by hand, but should there be any difficulty due to an over-tight fit, insert a screwdriver or similar tool in a twisting motion, as shown in Fig. 9.14.

2) In order to augment the dust and waterproofing effects, completely fill the space between the two lips of the rubber seal incorporated in the cover with grease, and apply grease to the inside of the cover, filling about two-thirds of the space. Cup grease is commonly used for this purpose (Fig. 9.15).

Fig. 9.15

3) First, pass one of the two grease-packed covers along the shaft, and then slide the bearing unit onto the shaft and fix the inner ring fast on the shaft before tightening the bolts holding the housing. Sometimes these steps are reversed for convenience of assembly. It is recommended that the end of the shaft be chamfered beforehand to avoid damaging the lips of the rubber seal. 4) Next take the cover which has been passed along the shaft and press it into the housing as follows: Be careful not to strike the surface of the steel cover directly with a steel hammer but use a synthetic resin or wood block in between. Do not strike only in one place but tap the cover all the way round until it is firmly seated in the housing. (Fig. 9.16) The cast iron cover is fastened with three bolts.

Fig. 9.14

Fig. 9.16

42

Technical Data

NTN

5) Pack the second cover with grease as in step 2 and pass it along the shaft. In the case of a blind cover, the recess of the housing should be filled with grease (Fig. 9.15). 6) Fit the cover into the recess of the housing using the same procedure as detailed in Step 4) (Fig. 9.17).

9.5 Dismounting the bearing unit
If some abnormality makes it necessary to dismount the bearing unit from the shaft in order to replace it, the procedure used to mount the bearing is followed in reverse order. In this case, special care should be given to the following points: 1) Set screw system units: If the set screw is protruding into the bore of the bearing when the unit is withdrawn from the shaft, it will damage the shaft. Therefore the screw should be turned back fully. 2) Adapter system units: To remove an adapter system bearing unit from the shaft, raise the tab of the washer, turn the nut two or three turns back, and apply a metal block to the nut and tap it with a hammer. Do this all round the nut, until the sleeve can be moved (Fig. 9.18). If the nut is turned back too far and the screws are only slightly engaged, tapping to remove it will eventually ruin the screws.

Fig. 9.17

9.3 Running tests
After mounting the bearing unit, check that it has been done correctly. First, turn the shaft or the rotor by hand to make certain that it rotates smoothly. If there is no irregularity, start up the machine. Run the machine at low speed under no load and gradually bring it up to full operating speed while checking that there are no abnormalities. Some indications of abnormality or faulty assembly are as follows: When the shaft is turned by hand a resistance or drag is felt, or the shaft appears to become heavy or light in turn. Or, if the machine is running under power, any abnormal noise, vibration or overheating is evident.

Fig. 9.18

9.6 Replacement of the bearing
If the bearing in the NTN bearing unit needs to be replaced, this can be carried out simply with a plummer block. There is no need to replace the housing, as it is reusable. The bearing is changed using the following procedure: First, the set screw should be tightened as much as possible. Otherwise, there is a danger that it may catch in the housing when the bearing is tilted. Next, insert the handle of a hammer or similar tool into the bore of the bearing and twist. Tilt the bearing through a full 90, and pull it in the direction of the notch on the housing to remove it. To install a new bearing in the housing, follow the same procedure in reverse.

9.4 Inspection during operation
Although the NTN lubrication-free bearing unit does not require refilling with grease while in use, periodic inspections are necessary to ensure safe operation of the unit's most important parts. While the interval between inspections varies from case to case, according to the degree of importance and the rate of operation, it is usually some time between two weeks and a month. Since the inside of the bearing can be examined only by removing the slinger, seal etc., the condition of the bearing should be judged by checking for the presence of vibration, noise, overheating of the housing, etc., while the machine is running.

43


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