2

Contents

NMB Minebea - about ourselves 4

Part numbering system, Pelmec ball bearings 6
Part numbering system, M+I ball bearings 7

NMB ball bearings – dimensions

Deep groove single row ball bearings (metric) 8
Flanged deep groove single row ball bearings (metric) 14
Deep groove single row ball bearings (imperial) 18
Flanged Deep groove single row ball bearings (imperial) 20
Deep groove single row ball bearings with snap ring 21

Information on applications
Materials for rings and roller bodies 22
Bearing cover disc 23
Retainer 24
Measurement methods 25
Roller bearing tolerances 26
Corner radii 29
Bearing clearance 30
Lubrication 31
Service life - static loadability 32
Pre-stressing/ bearing adjustment 33
Preload 34
Fitting 36
Bearing deflection, yield 37
Vibration from Rotation 40
Installation tolerances 41
Handling ball bearings 41
Mechanical components 42
Engineering support 44
Sample copy of request form 45
Notes 46

3
 About ourselves
NMB Minebea is the world’s leading manufacturer of minia-
ture ball bearings. With over 45,000 employees in 70 locations,
200 sales organisations and 40 manufacturing facilities,
NMB Minebea is now a true multi-national concern.

Founded in Tokyo in 1951, NMB (Nippon Miniature Bearings)

started with the development and manufacture of miniature ball
bearings. Over the following years, the product range was conti-
nuously extended. In nine different countries, the concern now
manufactures miniature ball bearings, ventilators and blowers
(air-movers), computer keyboards, stepper and geared motors, hi-
fi loudspeakers and disk drives and today is one of the biggest
manufacturers of industrial components.

The manufacturing process known as the ‘vertical integration

manufacturing system’ has its essential feature in the fact that
almost all individual parts for an NMB Minebea finished product
are manufactured internally.
The manufacturing depth on the one hand, and on the other the
development and construction of assembly lines, machines, tools
and devices for manufacturing processes together guarantee an
optimum standard of quality for all our products.

As a leading components manufacturer, today NMB Minebea is

active globally – in Japan, Mexico, Brazil, Singapore, Taiwan,
Thailand, the USA, China and in Europe.

4
The NMB Minebea ball bearings group offers technical support in
Germany, in Langen (Hess) and Villingen. Thus the group is repre-
sented in Central Europe and in close proximity to its customers.
There are further technology centres in England, Japan, Singa-
pore, Thailand and the USA.
Our technology centres are equipped with all the usual equip-
ment for examination of ball bearings, as well as for product and
application analysis.

In addition to the continuing further development of our ball

bearing range, high-precision mechanical components (assemblies)
are developed according to special customer requirements to the
production stage and then put into series production.

Manufacturing and inspection processes are being continually

developed to improve our product standards even further. Raw
materials and lubricant testing, noise-testing and measurement
all belong to the day-to-day standards in our production. The
level of vertical integration makes it possible for us to
manufacture all of the components for miniature ball bearings,
such as inner and outer rings, balls, retainer, covers and sealing
discs in the widest possible variety. As raw material, we use a sel-
ection of chrome steel and stainless steel. Similarly, various types
of radial bearings and lubricants (grease and oils) are available
for both normal and exceptional service and applications.
Manufacturing is carried out either in accordance with JIS (ISO) or
AFBMA standards (ABEC).

Today, NMB Minebea provides a wide range of services. These

extend from individual customer advice to planning and design
specifications of ball bearings. Similarly, we offer services
accompanying projects, ball bearing analysis and functional and
endurance-testing.

The high level of quality of our products is achieved through con-

tinuous and permanent quality checking. NMB-Minebea-GmbH is
ISO 9000 and ISO/TS 16949 as the remote location certificated.
Our production facilities are ISO 9000, QS 9000, ISO/TS 16949 and
ISO 14001 certificated.

CFC-free and trichloroethylene-free manufacture was introduced

in our factories in the early 1990s. In 1993, 1995 and 1997
NMB Minebea was awarded the accolade ‘Best of the Best’ by
the American Environmental Protection Agency on this account.

We count amongst our customers market leading companies in

the automotive industry, ventilator, blower, measuring device,
domestic equipment and electric motor manufacturers.

We are therefore not merely a reliable supplier, but also a

partner on both a local and a global scale.

5
 PELMEC* Parts numbering system
*PELMEC: Precision ELectro MEChanic Bearings
This numbering system is valid for the following part numbers:
607, 608, 609, 626, 627, 629, 635, 6000, 6001

608 MN ZZ M5 MT A5 LY121 H

Size Lubricant content

See Pages 8–21 L 10-15%

T 15-20%
– 25-35%
H 40-50%
Retainer type
See Page 31
MN Crown
(fibreglass-
reinforced
Plastic)
J Crown
(Plastic)
- Ribbon Lubricants
(steel)
See Page 31
See Page 24

Cover disk Tolerance classes

Z Steel shield - ABEC 1P

(pressed in) A5 ABEC 5P
D Rubber seal
(contact) See Pages 26–28
S Rubber seal
(non-contact)

See Page 23

Radial bearing Noise class

clearance
MT E-motor quality
M2 3 - 8 µm SM Standard noise
M3 5 - 10 µm tested
M4 8 - 13 µm
M5 13 - 20 µm

See Page 29

6 Further characteristic specifications are available on request

M+I*-Parts numbering system
*M+I: Miniature + Instrument Bearings

DD R 2280 HH MT R A1 P25 LY121 H

Material Lubricant content

- Chrome steel L 10-15 %

DD Stainless steel T 15-20 %
- 25-35 %
See Page 22 H 40-50 %
See Page 31
Series

R: R-series, metric (D/d large) Lubricants

RF: R-series, flanged, metric
RI: R-series, imperial
See Page 31
RIF: R-series, imperial, flanged
L: L-series, metric (D/d small)
LI: L-series, imperial Radial bearing
LIF: L-series, metric, flanged clearance
A: A-series (D/d very small)
P13 2,5 - 7,5 µm
See Pages 8-21 P24 5,0 - 10 µm
P25 5,0 - 12,5 µm
P58 12,5 - 20 µm
Sizes See Page 29

See Pages 8-21

Tolerance classes

H,K,K1 Shield A1 ABEC 1P

(pressed in) A5 ABEC 5P
Z Shield See Pages 25-27
(secured with
snap ring)
D Rubber seal
(contact) Retainer type
S Rubber seal
(non-contact) MN Crown
L PTFE disc (Plastic, glass-
fibre reinforced
See Page 23 J Crown
(Plastic)
H Crown
(Steel)
Noise class
R Two-part Ribbon
- Standard noise (steel)
tested See Pages 26–28
MT E-motor quality

Further characteristic specifications are available on request. 7

 Deep groove single row ball bearings (metric)

bore outer width JIS/ISO NMB NMB Da di ball no. Dyn. Stat.
Ø Ø B designation designation (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

1 3 1 618/1 L-310 2,41 1,60 0,5000 7 80 23

1 3 1,5 638/1 L-310W51 2,41 1,60 0,5000 7 80 23

1 4 1,6 619/1 R-410 3,16 2,05 0,7938 6 158 44

1 4 2 - R-410ZZ 3,42 2,15 0,6000 7 113 34

1,2 4 1,2 - R-412 3,16 2,05 0,7938 6 158 44

1,5 4 1,2 618/1,5 L-415 3,25 2,26 0,6350 7 125 38

1,5 4 2 638/1,5 L-415X5ZZ 3,42 2,15 0,6000 7 113 34

1,5 4 2 638/1,5 L-415ZZ 3,49 2,26 0,6350 7 125 38

1,5 4 2,5 - L-415ZZW52 3,49 2,26 0,6350 7 125 38

1,5 5 2 619/1,5 R-515 3,73 2,60 0,7938 7 184 57

1,5 5 2,6 639/1,5 R-515ZZ 4,03 2,60 0,7938 7 184 57

1,5 6 2,5 610/1,5 R-615 4,73 2,90 1,1906 6 324 97

2 5 1,5 618/2 L-520 4,00 2,90 0,7938 7 187 59

2 5 2 - L-520W02 4,00 2,90 0,7938 7 187 59

2 5 2,3 638/2 L-520ZZ 4,28 2,90 0,7938 7 187 59

2 5 2,5 - L-520ZZW52 4,28 2,90 0,7938 7 187 59

2 5 2,5 - L-520W52 4,00 2,90 0,7938 7 187 59

2 6 2,3 619/2 R-620 4,78 3,16 1,0000 7 279 89

2 6 2,3 619/2 R-620ZZY32 5,23 3,16 1,0000 7 279 89

8
bore outer width JIS/ISO NMB NMB Da di ball no. Dyn. Stat.
Ø Ø B designation designation (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

2 6 2,5 - R-620W52 5,23 3,10 1,1906 6 330 99

2 6 2,5 - R-620ZZY52 5,23 3,10 1,1906 6 330 99

2 6 3 639/2 R-620ZZ 5,23 3,10 1,1906 6 330 99

2 6 3 639/2 R-620W03 4,93 3,10 1,1906 6 330 99

2 7 2,5 - R-720Y52 5,52 3,80 1,1906 7 380 126

2 7 2,8 610/2 R-720 5,52 3,80 1,1906 7 380 126

2 7 3 - R-720ZZY03 5,93 3,80 1,1906 7 380 126

2 7 3,5 630/2 R-720ZZ 5,93 3,80 1,1906 7 380 126

2,5 6 1,8 618/2,5 L-625 4,93 3,80 0,7938 8 206 73

2,5 6 2,6 638/2,5 L-625ZZ 5,23 3,80 0,7938 8 206 73

2,5 7 2,5 619/2,5 R-725 5,52 3,80 1,1906 7 380 126

2,5 7 3 - R-725ZZY03 5,93 3,80 1,1906 7 380 126

2,5 7 3,5 639/2,5 R-725ZZ 5,93 3,80 1,1906 7 383 126

2,5 8 2,8 610/2,5 R-825 6,53 4,10 1,5875 6 553 176

2,5 8 2,8 610/2,5 R-825ZZY82 6,89 4,77 1,1906 8 426 156

2,5 8 4 630/2,5 R-825ZZ 7,19 4,10 1,5875 6 553 176

3 6 2 617/3 L-630 4,93 3,80 0,7938 8 206 73

3 6 2,5 - L-630ZZ 5,23 3,80 0,7938 8 206 73

3 7 2 618/3 L-730 5,83 4,10 1,1906 7 384 129

3 7 3 638/3 L-730ZZ 6,13 4,10 1,1906 7 384 129

3 7 3 638/3 L-730W03 5,83 4,10 1,1906 7 384 129

3 8 2,5 - R-830Y52 6,53 4,10 1,5875 6 553 176

3 8 3 619/3 R-830 6,53 4,10 1,5875 6 553 176

3 8 3 619/3 R-830ZZY03 6,89 4,77 1,1906 8 426 156

3 8 4 639/3 R-830ZZ 7,20 4,10 1,5875 6 553 176

3 9 2,5 - R-930Y52 7,23 4,80 1,5875 7 634 219

3 9 3 610/3 R-930 7,23 4,80 1,5875 7 634 219

3 9 4 - R-930ZZY04 7,64 4,80 1,5875 7 634 219

3 9 5 630/3 R-930ZZ 7,64 4,80 1,5875 7 634 219

3 10 4 623 R-1030 8,20 5,08 1,5875 7 641 226

3 10 4 623 R-1030ZZ 8,20 5,08 1,5875 7 641 226

4 7 2 617/4 L-740 5,93 4,80 0,7938 11 252 106

9
Deep groove single row ball bearings (metric)
bore outer width JIS/ISO NMB NMB Da di ball no. Dyn. Stat.
Ø Ø B designation designation (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

4 7 2,5 - L-740ZZ 6,33 4,80 0,7938 11 252 106

4 8 2 - L-840 6,93 5,20 1,1906 7 384 140

4 8 3 - L-840W03 7,24 5,20 1,1906 7 384 140

4 8 3 - L-840ZZ 7,24 5,20 1,1906 7 384 140

4 9 2,5 618/4 L-940 7,48 5,20 1,5875 7 641 226

4 9 3,5 628/4 L-940ZZY53 7,31 5,62 1,1906 7 391 142

4 9 4 638/4 L-940ZZ 7,93 5,20 1,5875 7 641 226

4 10 3 - L-1040X2 7,96 5,80 1,5875 8 708 266

4 10 4 - L-1040X2ZZ 8,50 5,46 1,5875 8 708 265

4 11 4 619/4 R-1140 9,53 6,40 1,5875 8 708 276

4 11 4 619/4 R-1140ZZ 9,54 6,40 1,5875 8 708 276

4 12 4 610/4 R-1240 9,99 5,62 2,0000 7 959 347

4 12 4 610/4 R-1240ZZ 9,99 5,62 2,0000 7 959 347

4 13 5 624 R-1340 11,20 5,97 2,3813 7 1306 487

4 13 5 624 R-1340HH 11,20 5,97 2,3813 7 1306 487

4 16 5 634 R-1640 13,41 7,80 2,7782 7 1735 671

4 16 5 634 R-1640HH 13,41 7,80 2,7782 7 1735 671

5 8 2 617/5 L-850 6,95 5,80 0,7938 13 274 130

5 8 2,5 - L-850ZZ 7,26 5,80 0,7938 13 274 130

5 9 2,5 - L-950 7,73 6,00 1,1906 10 495 207

5 9 3 - L-950ZZ 8,04 6,00 1,1906 10 495 207

5 10 3 - L-1050 8,63 6,40 1,5875 8 714 276

5 10 4 - L-1050ZZ 8,94 6,40 1,5875 8 714 276

5 11 3 618/5 L-1150 8,63 6,40 1,5875 8 714 276

5 11 4 628/5 L-1150ZZY04 9,54 6,95 1,5875 7 714 276

5 11 5 638/5 L-1150ZZ 9,54 6,40 1,5875 8 714 276

5 13 4 619/5 R-1350 11,14 6,66 2,0000 8 1074 422

5 13 4 619/5 R-1350ZZ 11,14 6,66 2,0000 8 1074 422

5 13 5 - R-1350W05 11,04 7,00 2,3813 7 1306 487

5 13 5 - R-1350ZZW05 11,04 7,00 2,3813 7 1306 487

5 14 5 610/5 R-1450 12,14 6,88 2,3813 7 1329 508

5 14 5 610/5 R-1450ZZ 12,14 6,88 2,3813 7 1329 508

10
bore outer width JIS/ISO NMB NMB Da di ball no. Dyn. Stat.
Ø Ø B designation designation (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

5 16 5 625 R-1650 13,41 7,80 2,7782 7 1735 671

5 16 5 625 R-1650HH 13,41 7,80 2,7782 7 1735 671

5 19 6 635 635 16,60 10,60 3,5000 7 2614 1059

5 19 6 635 635ZZ 16,60 9,20 3,5000 7 2614 1059

5 19 6 635 R-1950 16,26 8,67 3,9689 6 2815 1069

5 19 6 635 R-1950ZZ 16,26 8,67 3,9689 6 2815 1069

6 10 2,5 617/6 L-1060 8,73 6,95 1,1906 9 457 194

6 10 3 - L-1060ZZ 9,04 6,95 1,1906 9 457 194

6 12 3 - L-1260 9,94 7,70 1,5875 10 834 363

6 12 4 - L-1260ZZ 10,48 7,70 1,5875 10 834 363

6 13 3,5 618/6 L-1360 10,98 8,00 2,0000 8 1083 438

6 13 4,5 - L-1360ZZY54 11,44 7,33 2,0000 8 1083 438

6 13 5 628/6 L-1360ZZ 11,44 7,33 2,0000 8 1083 438

6 15 5 619/6 R-1560X2 13,20 7,80 2,7782 7 1735 671

6 15 5 619/6 R-1560X2ZZ 13,20 7,80 2,7782 7 1735 671

6 16 5 - R-1660HH 13,41 7,80 2,7782 7 1735 671

6 17 6 610/6 R-1760X2 14,70 8,22 3,5000 6 2265 839

6 17 6 610/6 R-1760X2ZZ 14,70 8,22 3,5000 6 2265 839

6 19 6 626 626 16,68 9,20 3,5000 7 2614 1059

6 19 6 626 626ZZ 16,68 9,20 3,5000 7 2614 1053

6 19 6 626 R-1960 16,26 8,67 3,9689 6 2815 1053

6 19 6 626 R-1960ZZ 16,26 8,67 3,9689 6 2815 1069

6 19 6 626 626ZZSD02 16,68 10,60 3,5000 7 2614 1053

7 11 2,5 617/7 L-1170 9,83 8,10 1,1906 9 449 199

7 11 3 - L-1170ZZ 10,14 8,10 1,1906 9 449 199

7 13 3 - L-1370 11,13 8,90 1,5875 11 883 414

7 13 4 - L-1370ZZ 11,54 8,43 1,5875 11 883 414

7 14 3,5 618/7 L-1470 12,03 9,00 2,0000 9 1175 511

7 14 5 628/7 L-1470ZZ 12,45 9,00 2,0000 9 1175 511

7 17 5 619/7 R-1770HH 14,20 9,68 2,3813 9 1606 712

7 19 6 607 R-1970 16,24 9,55 3,1750 7 2246 912

7 19 6 607 R-1970ZZ 16,24 9,55 3,1750 7 2246 912

11
Deep groove single row ball bearings (metric)
bore outer width JIS/ISO NMB NMB Da di ball no. Dyn. Stat.
Ø Ø B designation designation (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

7 19 6 607 607 16,68 9,20 3,5000 7 2614 1059

7 19 6 607 607ZZ 16,68 9,20 3,5000 7 2614 1059

7 19 6 607 607ZZSD02 16,68 10,60 3,5000 7 2614 1059

7 22 7 627 627 19,02 10,80 3,9688 7 3297 1368

7 22 7 627 627ZZ 19,02 10,80 3,9688 7 3297 1368

7 22 7 627 R-2270 19,08 10,80 3,9688 7 3297 1368

7 22 7 627 R-2270ZZ 18,89 10,80 3,9688 7 3297 1368

7 22 7 627 627ZZSD02 19,10 12,40 3,9688 7 3297 1368

8 12 2,5 617/8 L-1280 10,93 9,10 1,1906 11 510 255

8 12 3,5 637/8 L-1280ZZ 11,24 9,10 1,1906 11 510 255

8 14 3,5 - L-1480 12,13 9,90 1,5875 10 819 386

8 14 4 - L-1480ZZ 12,55 9,90 1,5875 10 819 386

8 16 4 618/8 L-1680 13,63 10,40 2,3813 9 1606 712

8 16 5 628/8 L-1680HH 14,20 9,68 2,3813 9 1606 712

8 16 5 628/8 L-1680X2HH 14,18 10,30 2,3813 9 1606 712

8 16 6 638/8 L-1680HHW06 14,20 9,68 2,3813 9 1606 712

8 19 6 619/8 R-1980 16,68 10,60 3,1750 8 2463 1059

8 19 6 619/8 R-1980HH 16,68 10,60 3,1750 8 2463 1059

8 19 8 - R-1980HHW08 16,68 10,60 3,1750 8 2463 1059

8 22 7 608 608 19,10 10,80 3,9688 7 3297 1368

8 22 7 608 608ZZ 19,10 10,80 3,9688 7 3297 1368

8 22 7 608 R-2280 19,07 10,80 3,9688 7 3297 1368

8 22 7 608 R-2280ZZ 18,89 10,76 3,9688 7 3297 1368

8 22 7 608 608ZZSD02 19,10 12,40 3,9688 7 3297 1368

8 24 8 628 R-2480HH 19,10 12,00 3,9688 7 3297 1368

9 17 4 618/9 L-1790 14,84 11,20 2,3813 10 1724 813

9 17 5 628/9 L-1790ZZ 15,34 11,20 2,3813 10 1724 813

9 20 6 619/9 L-2090 17,74 12,32 2,7782 9 2123 985

9 20 6 619/9 L-2090ZZ 17,44 12,32 2,7782 9 2123 985

9 24 7 609 609 19,10 12,40 3,9688 7 3297 1368

9 24 7 609 609ZZ 19,00 12,40 3,9688 7 3297 1368

9 26 8 629 629 22,80 12,88 4,7625 7 4581 1972

12
bore outer width JIS/ISO NMB NMB Da di ball no. Dyn. Stat.
Ø Ø B designation designation (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

9 26 8 629 629ZZ 22,80 12,88 4,7625 7 4581 1972

9 26 8 629 R-2690 21,25 13,80 4,7625 7 4578 1970

9 26 8 629 R-2690ZZ 22,65 13,80 4,7625 7 4578 1970

10 15 3 61700 A-1510 13,60 11,25 1,5875 11 857 435

10 15 4 - A-1510ZZ 14,00 11,25 1,5875 11 857 435

10 19 5 61800 L-1910 17,74 12,32 2,7782 9 2123 985

10 19 5 61800 L-1910ZZY05 17,40 12,32 2,7782 9 2123 985

10 19 7 63800 L-1910ZZ 17,44 12,32 2,7782 9 2123 985

10 19 7 63800 L-1910W07 17,44 12,32 2,7782 9 2123 985

10 20 5 - L-2010ZZY05 17,44 12,32 2,7782 9 2123 985

10 20 6 - L-2010ZZ 17,44 12,32 2,7782 9 2123 985

10 22 6 61900 R-2210X3HHSD21 19,40 13,40 3,1750 9 2697 1273

10 26 8 6000 6000ZZ 22,80 13,75 4,7625 7 4578 1970

10 26 8 6000 6000 22,80 13,75 4,7625 7 4578 1970

10 26 8 6000 R-2610 21,25 14,80 4,7625 7 4578 1970

10 26 8 6000 R-2610ZZ 22,42 13,76 4,7625 7 4578 1970

12 21 5 61801 L-2112HH 19,60 14,74 2,3813 12 1917 1042

12 24 6 61901 R-2412X3ZZ 21,69 15,35 3,5718 8 3082 1433

12 28 8 6001 6001 24,50 16,65 4,76 8 5100 2360

12 28 8 6001 6001ZZ 24,50 16,65 4,76 8 5100 2360

15 20 3,5 - A-2015 18,43 16,40 1,5875 14 944 582

15 21 3,5 - A-2115 18,93 16,80 1,5875 14 938 581

15 24 5 61802 L-2415 22,00 17,70 2,3813 14 2076 1258

15 24 5 61802 L-2415ZZ 22,00 17,70 2,3813 14 2076 1258

16 22 4 - A-2216 19,90 17,80 1,5875 15 969 619

16 22 4 - A-2216ZZ 20,72 17,80 1,5875 15 969 619

18 24 4 - A-2418 21,90 19,75 1,5875 16 988 654

20 25 4 - A-2520 23,40 21,35 1,5875 17 1012 691

20 25 4 - A-2520ZZ 23,80 21,35 1,5875 17 1012 691

13
 Flanged deep groove single row ball bea-
rings (metric)

bore outer width JIS/ISO NMB-des. NMB-designation flange flange Da di ball no. Dyn. Stat.
Ø Ø B Ø width (mm) (mm) Ø of C Co
d D (mm) DF BF (mm) ball (N) (N)
(mm) (mm) (mm) (mm) bear.

1 3 1 618/1 LF-310 3,80 0,30 2,41 1,60 0,5000 7 80 23

1,5 4 1,2 618/1,5 LF-415 5,00 0,40 3,24 2,26 0,6350 7 125 38

1,5 5 2,6 639/1,5 RF-515 6,50 0,80 4,03 2,00 0,7938 7 186 59

1,5 5 2,6 639/1,5 RF-515ZZ 6,50 0,80 4,03 2,60 0,7938 7 186 59

1,5 6 3 RF-615ZZ 7,50 0,80 5,00 2,90 1,1906 6 334 98

2 5 1,5 618/2 LF-520 6,10 0,50 4,01 2,90 0,7938 7 187 59

2 5 2,3 638/2 LF-520ZZ 6,10 0,60 4,28 2,90 0,7938 7 186 59

2 6 2,3 619/2 RF-620 7,50 0,60 4,78 3,16 1,0000 7 279 89

2 6 2,5 - RF-620ZZY52 7,20 0,60 5,23 3,10 1,1906 6 330 99

2 6 3 639/2 RF-620ZZ 7,50 0,80 5,23 3,10 1,1906 6 334 108

2 7 3 - RF-720ZZY03 8,20 0,60 5,93 3,80 1,1906 7 380 126

2 7 3,5 630/2 RF-720ZZ 8,50 0,90 5,93 3,80 1,1906 7 383 128

2,5 6 1,5 LF-625Y51 7,10 0,50 4,93 3,80 0,7938 8 206 73

2,5 6 1,8 618/2,5 LF-625 7,10 0,50 4,93 3,80 0,7938 8 206 73

2,5 6 2,6 638/2,5 LF-625ZZ 7,10 0,80 5,23 3,80 0,7938 8 206 78

14
bore outer width JIS/ISO NMB-des. NMB-designation flange flange Da di ball no. Dyn. Stat.
Ø Ø B Ø width (mm) (mm) Ø of C Co
d D (mm) DF BF (mm) ball (N) (N)
(mm) (mm) (mm) (mm) bear.

2,5 7 3 - RF-725ZZY03 8,20 0,60 5,93 3,80 1,1906 7 380 126

2,5 7 3,5 639/2,5 RF-725ZZ 8,50 0,90 5,93 3,80 1,1906 7 383 128

2,5 8 2,8 610/2,5 RF-825 9,50 0,70 6,53 4,10 1,5875 6 553 176

2,5 8 4 630/2,5 RF-825ZZ 9,50 0,90 7,20 4,10 1/16 6 559 177

3 6 2 617/3 LF-630 7,20 0,60 4,93 3,80 0,7938 8 206 73

3 6 2,5 - LF-630ZZ 7,20 0,60 5,23 3,80 0,7938 8 206 78

3 7 2 618/3 LF-730 8,10 0,50 5,83 4,10 1,1906 7 384 129

3 7 3 638/3 LF-730ZZ 8,10 0,80 6,14 4,10 1,1906 7 392 137

3 8 2,5 - RF-830Y52 9,20 0,60 6,53 4,10 1,5875 6 553 176

3 8 3 619/3 RF-830 9,50 0,70 6,53 4,10 1,5875 6 553 176

3 8 4 639/3 RF-830ZZ 9,50 0,90 7,19 4,10 1,5875 6 553 176

3 9 4 - RF-930ZZY04 10,60 0,80 7,64 4,80 1,5875 7 638 226

3 9 5 630/3 RF-930ZZ 10,50 1,00 7,64 4,80 1/16 7 638 226

3 10 4 623 RF-1030ZZ 11,50 1,00 8,20 5,08 1,5875 7 647 226

4 7 2 617/4 LF-740 8,20 0,60 5,93 4,80 0,7938 11 252 106

4 7 2,5 - LF-740ZZ 8,20 0,60 6,33 4,80 0,7938 11 252 106

4 8 2 - LF-840 9,20 0,60 6,93 5,20 1,1906 7 391 140

4 8 3 - LF-840ZZ 9,20 0,60 7,24 5,20 1,1906 7 391 140

4 9 2,5 618/4 LF-940 10,30 0,60 7,48 5,20 1,5875 7 641 226

4 9 4 638/4 LF-940ZZ 10,30 1,00 7,93 5,20 1,5875 7 647 226

4 10 3 - LF-1040X2 11,20 0,60 7,96 5,80 1,5875 8 708 266

4 10 4 - LF-1040X2ZZ 11,60 0,80 8,50 5,46 1,5875 8 708 266

4 11 4 619/4 RFW-1140 12,60 0,80 8,60 6,40 1,5875 8 714 276

4 11 4 619/4 RF-1140ZZ 12,50 1,00 9,54 6,40 1,5875 8 714 276

4 12 4 RF-1240 13,50 1,00 9,99 5,62 2,0000 7 959 347

4 12 4 610/4 RF-1240ZZ 13,50 1,00 9,99 5,62 2,0000 7 959 347

4 13 5 624 RF-1340ZZ 15,00 1,00 11,04 7,00 2,3813 7 1306 487

4 16 5 634 RF-1640ZZ 18,00 1,00 13,20 7,80 2,3813 7 1735 671

5 8 2 617/5 LF-850 9,20 0,60 6,95 5,80 0,7938 13 274 130

5 8 2,5 - LF-850ZZ 9,20 0,60 7,26 5,80 0,7938 13 274 130

5 9 2,5 - LF-950 10,20 0,60 7,73 6,00 1,1906 10 495 207

5 9 3 - LF-950ZZ 10,20 0,60 8,04 6,00 1,1906 10 495 207

15
Flanged deep groove single row ball bearings (metric)
bore outer width JIS/ISO NMB-des. NMB-designation flange flange Da di ball no. Dyn. Stat.
Ø Ø B Ø width (mm) (mm) Ø of C Co
d D (mm) DF BF (mm) ball (N) (N)
(mm) (mm) (mm) (mm) bear.

5 10 3 - LF-1050 11,20 0,60 8,63 6,40 1,5875 8 714 276

5 10 4 - LF-1050ZZ 11,60 0,80 8,94 6,40 1,5875 8 714 276

5 11 3 618/5 LF-1150 12,50 0,80 8,63 6,40 1,5875 8 714 276

5 11 4 628/5 LF-1150ZZY04 12,60 0,80 9,54 6,40 1,5875 8 714 276

5 11 5 638/5 LF-1150ZZ 12,50 1,00 9,54 6,40 1,5875 8 714 276

5 13 4 619/5 RF-1350 15,00 1,00 11,14 6,66 2,0000 8 1074 422

5 13 4 619/5 RF-1350ZZ 15,00 1,00 11,14 6,66 2,0000 8 1074 422

5 13 5 - RF-1350ZZW05 15,00 1,00 11,04 7,00 2,3813 7 1306 487

5 14 5 610/5 RF-1450 16,00 1,00 12,14 6,88 2,3813 7 1329 508

5 14 5 610/5 RF-1450ZZ 16,00 1,00 12,14 6,88 2,3813 7 1334 510

5 16 5 625 RF-1650HH 18,00 1,00 13,41 7,80 2,7782 7 1736 677

5 19 6 635 RF-1950 22,00 1,50 15,60 8,67 3,9688 6 2805 1060

5 19 6 635 RF-1950ZZ 22,00 1,50 16,26 8,67 3,9688 6 2805 1060

6 10 2,5 617/6 LF-1060 11,20 0,60 8,73 6,95 1,1906 9 457 194

6 10 3 - LF-1060ZZ 11,20 0,60 9,04 6,95 1,1906 9 457 194

6 12 3 - LF-1260 13,20 0,60 9,94 7,70 1,5875 10 831 363

6 12 4 - LF-1260ZZ 13,60 0,80 10,48 7,70 1,5875 10 831 363

6 13 3,5 618/6 LF-1360 15,00 1,00 10,98 8,00 2,0000 8 1083 438

6 13 4,5 - LF-1360ZZY54 15,00 1,00 11,44 7,33 2,0000 8 1083 438

6 13 5 628/6 LF-1360ZZ 15,00 1,10 11,44 7,33 2,0000 8 1083 438

6 15 5 619/6 RF-1560 17,00 1,20 13,20 7,80 2,7782 7 1735 671

6 15 5 619/6 RF-1560ZZ 17,00 1,20 13,20 7,80 2,7782 7 1735 671

6 17 6 610/6 RF-1760X2ZZ 19,00 1,20 14,70 8,22 3,5000 6 2265 839

6 19 6 626 RF-1960ZZ 22,00 1,50 16,26 8,67 3,9688 6 2805 1060

7 11 2,5 617/7 LF-1170 12,20 0,60 9,83 8,10 1,1906 9 449 199

7 11 3 - LF-1170ZZ 12,20 0,60 10,14 8,10 1,1906 9 449 199

7 13 3 - LF-1370 14,20 0,60 11,13 8,90 1,5875 11 880 414

7 13 4 - LF-1370ZZ 14,60 0,80 11,54 8,43 1,5875 11 880 414

7 14 3,5 618/7 LF-1470 16,00 1,00 12,03 9,00 2,0000 9 1175 511

7 14 5 628/7 LF-1470ZZ 16,00 1,10 12,45 9,00 2,0000 9 1175 511

7 19 6 607 RF-1970ZZ 22,00 1,50 16,24 9,55 3,1750 7 2240 912

7 22 7 627 RF-2270HH 25,00 1,50 19,07 10,80 3,9688 7 3297 1368

16
bore outer width JIS/ISO NMB-des. NMB-designation flange flange Da di ball no. Dyn. Stat.
Ø Ø B Ø width (mm) (mm) Ø of C Co
d D (mm) DF BF (mm) ball (N) (N)
(mm) (mm) (mm) (mm) bear.

8 12 2,5 617/8 LF-1280 13,20 0,60 10,93 9,10 1,1906 11 506 249

8 12 3,5 637/8 LF-1280ZZ 13,60 0,80 11,24 9,10 1,1906 11 506 249

8 14 3,5 - LF-1480 15,60 0,80 12,13 9,90 1,5875 10 819 386

8 14 4 - LF-1480X3ZZ 15,60 0,80 11,77 9,20 1,5875 11 878 419

8 16 4 618/8 LF-1680 18,00 1,00 13,40 10,30 2,3813 9 1606 712

8 16 4 618/8 LFW-1680 17,60 0,80 13,40 10,30 2,3813 9 1606 712

8 16 5 628/8 LF-1680HH 18,00 1,10 14,20 9,68 2,3813 9 1606 712

8 16 6 638/8 LF-1680ZZW06 18,00 1,10 14,04 9,73 2,3813 9 1607 716

8 19 6 619/8 RF-1980 22,00 1,50 16,24 9,55 3,1750 7 2240 912

8 19 6 619/8 RF-1980ZZ 22,00 1,50 16,24 9,55 3,1750 7 2240 912

8 22 7 608 RF-2280 25,00 1,50 18,89 10,76 3,9688 7 3297 1368

8 22 7 608 RF-2280HH 25,00 1,50 19,07 10,80 3,9688 7 3297 1368

9 17 4 618/9 LF-1790 19,00 1,00 14,81 11,20 2,3813 10 1724 813

9 17 5 628/9 LF-1790ZZ 19,00 1,10 15,34 11,20 2,3813 10 1724 813

10 15 4 - AF-1510ZZ 16,50 0,80 14,04 11,25 1,5875 11 857 435

10 19 5 61800 LF-1910 22,00 1,50 16,68 12,32 2,7782 9 2123 985

10 19 5 61800 LF-1910ZZY05 22,00 1,50 17,44 12,32 2,7782 9 2123 985

10 19 7 63800 LF-1910ZZ 22,00 1,50 17,44 12,32 2,7782 9 2123 985

10 20 6 - RF-2210X2HH 25,00 1,50 19,08 12,40 3,1750 9 2697 1273

17
 Deep groove single row ball bearings
(imperial)

bore outer width NMB NMB Da di ball no. Dyn. Stat.

Ø Ø B designation designation (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

1,0160 3,1750 1,1913 RI-2x2 2,56 1,64 0,63500 6 106 28

1,1913 3,9675 1,5875 RI-21/2 3,16 2,05 0,79375 6 158 44

1,1913 3,9675 2,3800 RI-21/2ZZ 3,43 2,05 0,79375 6 158 44

1,3970 4,7625 1,9837 RI-3 4,02 2,36 1,19062 5 264 71

1,3970 4,7625 2,7788 RI-3ZZ 4,29 2,36 1,19062 5 264 71

1,9837 6,3500 2,3800 RI-4 4,90 3,10 1,19062 6 330 99

1,9837 6,3500 3,5712 RI-4ZZ 5,23 3,10 1,19062 6 330 99

2,3800 4,7625 1,5875 RI-3332 4,13 3,00 0,79375 7 187 59

2,3800 4,7625 2,3800 RI-3332ZZ 4,28 3,00 0,79375 7 187 59

2,3800 7,9375 2,7788 RI-5 6,88 4,40 1,58750 6 563 183

2,3800 7,9375 3,5712 RI-5ZZ 7,19 4,40 1,58750 6 563 183

3,1750 6,3500 2,3800 RI-418 5,52 4,10 1,00000 7 285 97

3,1750 6,3500 2,7788 RI-418ZZ 5,85 4,10 1,00000 7 285 97

18
 bore outer width NMB NMB Da di ball no. Dyn. Stat.
Ø Ø B designation designation (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

3,1750 7,9375 2,7788 RI-518 6,88 4,40 1,58750 6 563 183

3,1750 7,9375 3,5712 RI-518ZZ 7,19 4,40 1,58750 6 563 183

3,1750 9,5250 2,7788 RI-618 6,88 4,40 1,58750 6 563 183

3,1750 9,5250 3,5712 RI-618ZZ 7,20 4,40 1,58750 6 563 183

3,1750 9,5250 3,9675 R-2 7,65 5,08 1,58750 7 641 226

3,1750 9,5250 3,9675 R-2ZZ 8,19 5,08 1,58750 7 641 226

3,9675 7,9375 2,7788 RI-5532 7,08 5,62 1,19062 7 391 142

3,9675 7,9375 3,1750 RI-5532ZZ 7,31 5,62 1,19062 7 391 142

4,7625 7,9375 2,7788 RI-5632 7,08 5,62 1,19062 7 391 142

4,7625 7,9375 3,1750 RI-5632ZZ 7,31 5,62 1,19062 7 391 142

4,7625 9,5250 3,1750 RI-6632 8,72 5,97 1,58750 8 712 271

4,7625 9,5250 3,1750 RI-6632ZZ 8,72 5,97 1,58750 8 712 271

4,7625 12,7000 3,9675 R-3 10,49 7,00 2,38125 7 1306 487

4,7625 12,7000 4,9784 R-3HH 11,00 7,00 2,38125 7 1306 487

6,3500 9,5250 3,1750 RI-614 8,63 7,25 1,00000 13 417 205

6,3500 9,5250 3,1750 RI-614ZZ 8,88 7,25 1,00000 13 417 205

6,3500 12,7000 3,1750 RI-814 10,98 8,38 1,58750 10 828 374

6,3500 12,7000 4,7625 RI-814ZZ 11,55 8,38 1,58750 10 828 374

6,3500 15,8750 4,9784 R-4 13,03 8,20 2,38125 8 1470 599

6,3500 15,8750 4,9784 R-4HH 13,03 8,20 2,38125 8 1470 599

6,3500 19,0500 5,5575 RI-1214 15,19 9,80 3,57188 6 2411 912

6,3500 19,0500 7,1425 RI-1214ZZ 16,28 8,63 3,57188 6 2411 912

7,9375 12,7000 3,9675 RI-8516 11,44 9,20 1,58750 11 878 419

7,9375 12,7000 3,9675 RI-8516ZZ 11,77 9,20 1,58750 11 878 419

9,5250 22,2250 5,5575 RI-1438 18,83 13,22 3,96875 7 3297 1368

9,5250 22,2250 7,1425 RI-1438HH 19,08 12,40 3,96875 7 3297 1368

12,7000 28,5750 6,3500 RI-1812 24,05 17,18 4,76250 8 5113 2387

12,7000 28,5750 7,9375 RI-1812HH 25,13 16,00 4,76250 8 5113 2387

19
 Flanged deep groove single row
ball bearings (imperial)

bore Ø outer width NMB flange flange Da di ball no. Dyn. Stat.
d Ø B designation Ø width (mm) (mm) Ø of C Co
(mm) D (mm) DF BF (mm) ball (N) (N)
(mm) (mm) (mm) bear.

1,1913 3,9675 2,3800 RIF-21/2ZZ 5,156 0,787 3,43 2,05 0,79375 6 158 44

1,3970 4,7625 2,7788 RIF-3ZZ 5,944 0,787 4,29 2,36 1,19062 5 264 71

1,9837 6,3500 3,5712 RIF-4ZZ 7,518 0,787 5,23 3,10 1,19062 6 330 99

2,3800 4,7625 2,3800 RIF-3332ZZ 5,944 0,787 4,28 3,00 0,79375 7 187 59

2,3800 7,9375 3,5712 RIF-5ZZ 9,119 0,787 7,19 4,40 1,58750 6 563 183

3,1750 6,3500 2,7788 RIF-418ZZ 7,518 0,787 5,85 4,10 1,00000 7 285 97

3,1750 7,9375 3,5712 RIF-518ZZ 9,119 0,787 7,19 4,40 1,58750 6 563 183

3,1750 9,5250 3,5712 RIF-618ZZ 10,719 0,787 7,19 4,40 1,58750 6 563 183

3,1750 9,5250 3,9675 RF-2ZZ 11,176 0,762 8,19 5,08 1,58750 7 641 226

3,9675 7,9375 3,1750 RIF-5532ZZ 9,119 0,914 7,31 5,62 1,19062 7 391 142

4,7625 7,9375 3,1750 RIF-5632ZZ 9,119 0,914 7,31 5,62 1,19062 7 391 142

4,7625 9,5250 3,1750 RIF-6632ZZ 10,719 0,787 8,72 5,97 1,58750 8 712 271

4,7625 12,7000 4,9784 RF-3ZZ 14,351 1,067 11,04 7,00 2,38125 7 1306 487

6,3500 9,5250 3,1750 RIF-614ZZ 10,719 0,914 8,88 7,25 1,00000 13 417 205

6,3500 12,7000 4,7625 RIF-814ZZ 13,894 1,143 11,54 8,38 1,58750 10 828 374

6,3500 15,8750 4,9784 RF-4ZZ 17,526 1,067 13,04 8,20 2,38125 8 1470 599

7,9375 12,7000 3,9675 RIF-8516ZZ 13,894 0,787 11,77 9,20 1,58750 11 878 419

9,5250 22,2250 7,1425 RIF-1438HH 24,613 1,575 19,08 12,40 3,96875 7 3297 1368

20
Deep groove single row ball bearings with
snap ring

bore outer width JIS/ISO NMB designation DF BF Da di ball no. Dyn. Stat.
Ø Ø B (mm) (mm) (mm) (mm) Ø of C Co
d D (mm) (mm) ball (N) (N)
(mm) (mm) bear.

6 13 5 686ZZNR LNR-1360X3ZZ 14,5 1,10 10,48 7,7 1,58750 10 831 363

6 15 5 696ZZNR RNR-1560ZZ 17,2 1,5 13,20 7,8 2,77812 7 1735 671

6 17 6 606ZZNR RNR-1760X2ZZ 19,2 1,2 14,70 8,22 3,50000 6 2265 839

6 19 6 607ZZNR 22,1 1,5 16,68 9,20 3,50000 7 2614 1053

7 19 6 626ZZNR 22,1 1,5 16,68 9,20 3,50000 7 2614 1053

8 16 5 688ZZNR LNR-1680HH 18,2 0,95 14,18 9,68 2,38125 9 1606 712

8 22 7 608ZZNRSD03 24,8 2,95 19,10 10,80 3,96875 7 3297 1368

10 22 6 61900ZZNR RNR-2210X3HH 24,7 1,75 19,40 13,40 3,17500 9 2697 1273

10 26 8 6000ZZNR 29,2 2,31 22,88 13,75 4,76250 7 4578 1970

21
 Material for rings and roller bearing housings
Rings and roller bearing housings are made of very hard, very high purity roller bearing steel in
order to be able to withstand even the most extreme stresses. For this reason, only the most
carefully-assessed steel suppliers are selected.
NMB Minebea uses chrome steel for rings and roller bearing housings. In cases where resistance
to rust is important, stainless steel bearings are used. On request, ceramic roller bearing housings
are available for certain types of ball bearing.
NMB Minebea uses high quality, vacuum-degassed chrome steel complying with specification
JISG4805/SUJ2 or AISI/SAE 52100 or equivalent. With heat treatment, this steel attains a hardness
of 62 to 64 HRC and is thus suited to withstand high stresses over a long service life.
The NMB Minebea developed in-house stainless steel type DD400, when compared with other
steel types such as SUS440C/JISG4303/AISI440C, displays improved qualities in respect of hardness,
durability and stress resistance. The finer, more even structure of stainless steel DD400 results, in
comparison with ordinary stainless steel AISI/440C, in reduced levels of noise. In addition, DD400
has enhanced properties of rust resistance as compared with AISI/440C (according to ASTM-A380).

chrome steel composition

standard designation C Si Mn P S Cr Mo

JISG4805 SUJ2 0.95-1.10 0.15-0.35 0.5 MAX 0.025 MAX 0.025 MAX 1.3-1.6 –

AISI 52100 0.98-1.10 0.15-0.35 0.25-0.45 0.025 MAX 0.025 MAX 1.3-1.6 –

stainless steel composition

standard designation C Si Mn P S Cr Mo

– DD400 0.6-0.75 1.00 MAX 1.0 MAX 0.03 MAX 0.02 MAX 11.50-13.50 0.3 MAX

JISG4303 SUS440C 0.95-1.2 1.00 MAX 1.0 MAX 0.04 MAX 0.03 MAX 16.00-18.00 *

* It is also possible to add a maximum of 0.75% molybdenum.

Standard grade percentage composition

C Si Mn P S Ni Cr

JISG4303 SUS304 0.08 MAX 1.00 MAX 2.00 MAX 0.045 MAX 0.03 MAX 8.0~10.5 18.0~20.0

JISG4303 SUS410 0.15 MAX 1.00 MAX 1.00 MAX 0.04 MAX 0.03 MAX ** 11.5~13.5

JISG3141 SPCC 0.12 MAX – 0.50 MAX 0.04 MAX 0.045 MAX – –

** 0.6 % of Nickel is permissible.

22
Bearing cover disc
Covers protect the ball bearing from dirt and moisture penetration, and at the same time prevent
the lubricant from escaping. The NMB Minebea range covers ball bearings with cover discs (non-
contact) and sealing discs (contact).

Non-contact shields
The narrow gap between the inner ring and the cover disc and the maze effect created by the
geometry of the inner ring make it difficult for dirt to penetrate from outside. Since there is no
contact between inner ring and cover disc, the negative effects of any friction being generated
are avoided.
Metal shields
Metal shields are made of coated deep-drawn sheet metal or stainless steel and, according to ball
bearing type are either pressed into place in the outer ring (figure A.), or secured in place with a
snap ring (figure B).

Rubber seals
Non-contact rubber seals are made of Perbunan® (NBR) with a steel plate insert, and may be used
in temperatures of up to 120 °C. The rubber seals are snapped into place in the outer ring of the
bearing (figure C). The cover gap between the inner ring and the cover disc is much less than in
the case of cover discs of metal.

Contact shields
Contact shields provide much better protection against the penetration of dirt and moisture.
However, through the rubbing contact between inner ring and sealing disc, there are extra fric-
tional influences generated.
Rubber seals
Contact rubber seals are also made of Perbunan® (NBR) with a steel plate insert, and may also be
used in temperatures of up to 120 °C. The rubber seals are snapped into place in the outer ring
of the bearing. The sealing lip has contact with the inner ring (figure D).

A. Non removable B. Removable C. Non contact D. Contact

metal shield metal shield rubber seal rubber seal

For higher temperature requirements or chemical resistance, sealing discs in EPDM or HNBR (up
to approx. 130 °C), ACM (up to approx. 150 °C), or Teflon (>200 °C) may also be used. Additionally,
it is possible to develop special sealing discs with specific sealing lip geometry for particular appli-
cations. In this way, length of service life can be assured even in more polluted environments, or
lower rates of lubricant loss. However, such special covers must only be used after consultation
with NMB Minebea.

Cover disc NMB PELMEC NMB M+I DIN/ISO

Steel shield + snap ring Z Z
Steel shield elastic – H Z
Steel shield pressed-in deformed zinc-plated Z K Z
deformed stainless steel – K1 Z
Rubber seal contact D D RS
non contact S S N/A (RS)
Teflon seal contact – L N/A (RS)
23
 Retainer
The function of the retainer is to maintain separation between the balls and so to prevent addi-
tional friction and heat developing, and also to distribute the load evenly. Retainers are mainly
manufactured from steel sheet or plastic.
The following types of retainer are used:

Snap in crown retainer

is used for low to medium speeds, where a very low
friction generation is required. The snap in crown retai-
ner is made of deep-drawn steel sheet and is used pri-
marily in the manufacture of very small sizes of ball
bearings.

Two-pieces ribbon retainer

The two-pieces ribbon retainer is also made of deep-
drawn steel sheet. It is characterised by its low starting
torque and an even friction torque. Due to the simpler
automation of the ball bearing assembly, the two-
pieces ribbon retainer is used for larger sizes of ball
bearings with very high production volumes.

Snap in moulded plastic retainer

The one-piece moulded plastic retainer is obtainable in
various materials such as fibreglass-reinforced polyami-
de or polyacetate. As a general rule moulded plastic
retainers are for higher-speed applications. Through
their incase emergency running properties, moulded
plastic retainers also demonstrate advantages when
applied in difficult lubrication situations.

Application temperature is restricted according to the material of which the retainer is made.
Chemical resistance must also be checked beforehand by NMB Minebea.

Type Material NMB PELMEC NMB M+I DIN/ISO

Steel sheet H JH
one-piece snap in Fibreglass-reinforced polyamide MN MN TNH
Polyamide ‘Nylon’ J M7 TNH
Polyacetate ‘Delrin’ J TNH
Two-pieces Steel sheet without R J

24
Measurement methods
NMB Minebea supply bearings for a variety of applications, many of which require extreme levels
of high precision and accuracy. A ball bearing is an essential component the performance of
which is fundamental to the operating performance of the machine.
NMB Minebea have worke for many years to obtain the reputation that we proudly deserve for
dimensional accuracy and reliability. To maintain our current levels of excellence, we need to con-
tinue to use purpose built precision machinery such as: Talyronds, Talysurfs, Anderonmeters, as
well as equipment that has been designed, developed and manufactured ‘in-house’. For definiti-
ons and illustrations of Methods of Measurements, please refer to Sec. JISB 1515 (ISO/TR 9274).

Rotational Accuray
(1) Inner Ring Cylindrical Bore Run Out with Side (Sd) – see fig. 2-1
(2) Outside Cylindrical Surface Run Out with Side (SD) – see fig. 2-2
(3) Radial Run Out - Inner Ring (Kia) – see fig. 2-3
Radial Run Out - Outer Ring (Kea) – see fig. 2-4
(4) Axial Run Out - Inner Ring (Sia) – see fig. 2-5
Axial Run Out - Outer Ring (Sea) – see fig. 2-6

25
 Ball bearings tolerances
NMB Minebea ball bearings are manufactured in accordance with JIS B 1514 (ISO 492) or AFBMA.
The following symbols are used:

Dimensions:
d = nominal bore diameter
D = nominal diameter of outer ring
B = nominal width of inner ring
C = nominal width of outer ring

Variances
Δds = Variance of an individual bore diameter
Δdmp = Variance of the average bore diameter on one plane
ΔDs = Variance of an individual external diameter
ΔDmp = Variance of the average external diameter on one plane
ΔBs = Variance of an individual inner ring width
ΔCs = Variance of an individual outer ring width

Fluctuations
VDp = Fluctuation of the outer diameter in an individual radial plane
VDmp = Fluctuation of the average external diameter
Vdp = Fluctuation of the bore diameter in one radial plane
Vdmp = Fluctuation of the average bore diameter
VBs = Fluctuation of the inner ring width
VCs = Fluctuation of the outer ring width

True-running accuracy
Kia = True running of the inner ring of the assembled bearing (radial deviation)
Sia = Axial run-out of the inner ring side surfaces to the inner ring slideway of
the installed bearing (axial wobble)
Sd = Axial run-out of the inner ring side surfaces to the bore (side wobble)
Kea = True running of the outer ring of the assembled bearing
Sea = Axial run-out of the outer ring side surfaces to the outer ring slideway
of the installed bearing
SD = Fluctuation of the inclination of the surface line to the reference lateral
surface

26
Ball bearing tolerances ISO
Tolerances inner ring (bore = 18.0 mm as per ISO standard) - values in µm

tolerance Δdmp Δds Kia Sd Sia ΔBS VBS

class
P MAX. MIN. MAX. MIN. MAX. MAX. MAX. OT UT MAX.

0 0 -8 – – 10 – – 0 -40 *1 12 *1
-120 15 *2
20

6 0 -7 – – 5 *1
– – 0 -40 *1 12 *1
6 *2
-120 15 *2
7 20

5 0 -5 – – 4 7 7 0 -40 *2 5
-80

4 0 -4 0 -4 2.5 3 3 0 -40 *2 2.5

-80

2 0 -2.5 0 -2.5 1.5 1.5 1.5 0 -40 *2 1.5

-80

*1 = Bore ø ≤ 2,5 mm – *2 = Bore ø ≤ 10,0 mm

Tolerances outer ring (Ø = 30.0 mm as per ISO standard) - values in µm

tolerance ΔDmp ΔDs Kea SD Sea ΔCS VCS

class
P MAX. MIN. MAX. MIN. MAX. MAX. MAX. OT UT MAX.

0 0 -8 *1
– – 15 – – 0 *2 * 2
-9

6 0 -7 *1
– – 8 *1 – – 0 *2 * 2
-8 9

5 0 -5 *1
– – 5 *1 8 8 0 *2 5
-6 6

4 0 -4 *1
0 -4 *1 3 *1 4 5 0 *2 2.5
-5 -5 4

2 0 -2.5 *1
0 -2.5 *1 1.5 *1 1.5 1.5 *1 0 *2 1.5
-4 -4 2.5 2.5

*1 = Outer ø ≤ 18.0 mm
*2= Values see table above
Outer ring tolerance for width is identical with the inner ring tolerances.

27
 Ball bearing tolerances AFBMA
Tolerances inner ring (bore ≤ 18,0 mm as per AFBMA standard) - values in µm

tolerance Δdmp Δds Ki Sdi Si ΔBS VBS

class
ABEC MAX. MIN. MAX. MIN. MAX. MAX. MAX. OT UT MAX.

1P 0 -8 – – 10 – – 0 -40*1 12*1
-120 15*2
20

3P 0 -5.1 +2.5 -7.6 5.1 – – 0 -127 –

7.6

5P 0 -5.1 0 -5.1 3.8 7.6 7.6 0 -25.4 5.1

7P 0 -5.1 0 -5.1 2.5 2.5 2.5 0 -25.4 2.5

9P 0 -2.5 0 -2.5 1.3 1.3 1.3 0 -25.4 1.3

*1 = Bore ø ≤ 2,5 mm – *2 = Bore ø ≤ 10,0 mm

Tolerances outer ring (Ø = 30.0 mm as per ISO standard) - values in µm

tolerance ΔDmp ΔDs Ke SD Se ΔCS VCS

class
offenes Lager geschl. Lager

ABEC MAX. MIN. MAX. MIN. MAX. MIN. MAX. MAX. MAX. OT UT MAX.

1P 0 -8 *1
– – 15 – – – – 0 *2 *2
0 -9

3P 0 -7.6 +2.5 -10. 2 +5.1 -12.7 10.2 – – 0 -127 –

5P 0 -5.1*1 0 -5. 1 +1 -6.1 5.1 7.6 7.6 0 -25.4 5.1

7P 0 -5.1 0 -5. 1 +1 -6.1 3.8 3.8 5.1 0 -25.4 5.1

9P 0 -2.5*1 0 -2. 5 *1
– – 1.3*1 1.3 1.3*1 0 -25.4 1.3
0 -3.8 -3. 8 2.5 2.5

*1 = Outer ø ≤ 18.0 mm
*2= Values see table above
Outer ring tolerance for width is identical with the inner ring tolerances.

28
 Corner radii
The exact shape of the corner profile for the bearings is not laid down. It is
restricted solely by the minimum and maximum corner radii and the arc rsmin
(see ISO 582).

Values in mm

rsmin d rsmax ramax

Bore
Housing
> ≤ Radial direction Axial direction Shaft ø

0. 05 – – 0. 1 0. 2 0. 05
0. 08 – – 0. 16 0. 3 0. 08
0. 1 – – 0. 2 0. 4 0. 1
0. 15 – – 0. 3 0. 6 0. 15
0. 2 – – 0. 5 0. 8 0. 2

0. 3 – 40 0. 6 1. 0 0. 3

0. 6 – 40 1. 0 2. 0 0. 6

The exact shape of the corner profile is not laid down, but seen in radial section should lie wit-
hin the arc shown in the following diagram.

rsmax ramax

Axial Direction
rsmin Bore/housing
Bore/outer Ø shaft Ø
rsmin
Radial Direction
rsmax

ramax
r sm
in
Face
Inner/outer ring

Face housing
Shaft shoulder

ball bearing housing / shaft

ramax ≤ rsmin

29
 Bearing clearance
Bearing clearance is an extremely important characteristic. The right choice has a critical effect on
the service life, the running noise, vibration and temperature behaviour of a ball bearing. For this
reason, it is necessary to select the right bearing clearance class beforehand, in accordance with
the installation and application circumstances.
Bearing clearance may be affected either by pressure applied on the outer or inner ring, accor-
ding to the type of installation selected. Bearing clearance in the uninstalled bearing is therefo-
re separated into various bearing clearance classes. Standard values for ball bearing radial clea-
rances are laid down in ISO 5753. However, by comparison with ISO, NMB Minebea uses a more
exacting classification with substantially reduced tolerances.

NMB Minebea manufactures the ball bearings for two different product sectors. Pure M+I
(Miniature and Instrument) ball bearings with relatively small production volumes, primarily for
instrument manufacture, and Pelmec ball bearings with ISO designation for larger sizes. Each of
these product sectors use different designation systems for ball bearing clearance classes.

Radial designation for Pelmec ball bearings in µm

Radial play M1 M2 M3 M4 M5 M6
(standard) (standard)

Value in µm 0-5 3-8 5-10 8-13 13-20 20-28

Radial designation for M+I ball bearings in µm

Radial play P13 P24 P25 P35 P58

(standard) (standard)

Value in µm 2,5-7,5 5-10 5-12,5 7,5-12,5 12,5-20

As further characteristics, axial play and tilt angle can also be of interest. Axial play is not stan-
dardised, but can play an important role when for example establishing the overall axial play of
a motor driving shaft. The maximum tilt angle is a product of the inner bearing geometry and
the bearing clearance in installed position. The maximum tilt angle influences maximum permis-
sible alignment errors in the bearing system.

measured stress measured stress

RP

AP
2
RP Radial play

AP Axial play Tilt angle

30
Lubrication
Imperative for the service life of ball bearings is the selection of the correct lubricant. Choice of
the correct lubricant will also be a decisive influence on operating noise, friction, speed of rota-
tion and protection against corrosion.
Generally speaking, all NMB ball bearings are protected by a corrosion-resistant oil.
Sealed / shielded NMB ball bearings are greased during their production and therefore lubrica-
ted for life. Normally it isn’t possible to regrease miniature ball bearings. Open ball bearings are
normally oiled.
The major advantages of grease lubrication are the good sealing effect against penetration of
dirt from the outside, low level of maintenance required (lifetime lubrication) and the damping
effect on operating noise. Oil lubrication is ideal for gearing which is already oil-lubricated, or in
applications where a very low friction torque is required. Selection of the most suitable lubricant
depends on the application parameters. These are primarily the operating temperature, such
environmental influences as moisture and dust, and noise requirements. In the following lubri-
cation chart a selection of the standard oils and greases available from NMB are listed. Other
lubricants are also available at the customer’s request.

NMB Product Grundöl/ Basic oil/ Tempe- Application Typical

Code name Verdicker thickener rature purpose application
range

LO1 L-245X diester oil 3,5 / 11,8 -50/120 Instr. oil Rust prot. Rust protection (open bearing)

LY121 Multemp diester oil / 5,1 / 26 -40/120 Low noise, multi- Wide range of
SRL Lithium purpose, lubricant applications

LY342 Asonic diester oil / Lithium 5 / 25 -50/140 Low friction, Fan application
GLY 32 synthetic HC low noise electrical motor

LY532 Asonic HQ diester oil / 12 / 100 -40/180 Medium / higher Automotive

72-102 Polyurea temperature appl. applications

LY551 Multemp PAO / 7,9 / 47,6 -40/160 High temperature Vacuum cleaner fans /
K37 Polyurea Low friction electric tools

LY677 Fomblin PFPE/PTFE 45 / 159 -60/240 Highest Automotive

NMB PF1 temperature EGR, ABS

LY683 Klüberquiet Ester oil / 9 / 70 -45/180 High temperature / Automotive

BQ72-72 Polyurea Medium load Electrical motors

LY684 Klübersynth Ester oil / 9 / 53 -35/180 EPDM Automotive

HB 72-52 Polyurea Compatibility Oil pump motors

LY706 Klüberquiet Ester oil / 11 / 100 -40/180 High temperature / Automotive

BQH72-102 Polyurea Higher load Electrical motors

LY718 Klüberquiet Ester oil / 5 / 25 -50/150 Low temperature / Medical tool/

BQ 42-32 Lithium Smooth running Miniature power tool

Lubricant quantities
As a rule, in the case of greased bearings, 30 % of the unfilled space is filled with lubricant. By
request, however, varying amounts of lubricant may also be used. The following suffixes are used
to indicate the amount of lubricant in ball bearings:
L = 10 –15 % T = 15 – 20 % No Code 25 – 35% H = 40 – 50 % J= 50 – 60%

31
 Service life – static loadability
Service life
The standardised calculation process as per DIN ISO 281 for dynamically-stressed ball bearings is
based on material fatigue as the reason for failure. Here, the value Lh10 expresses the nominal
service life which at least 90 % of a large number of similar bearings must attain or exceed.

The nominal service life is calculated as follows:

The formula Lh10

Lh10 = nominal service life [h]

C = dynamic carrying figure [N]
P = dynamic equivalent loading
p = service life exponent (p = 3 for ball bearings)
n = rotation number [min-1]

The dynamic equivalent loading P for ball bearings is a mathematical value which converts exi-
sting radial and axial loading on the ball bearing into a constantly operative radial loading. The
dynamic carrying figure C is taken from the corresponding table in the ball bearing catalogue.

P=X* Fr + Y * Fa
where
P = dynamic equivalent loading
Fr = radial loading
Fa = axial loading
X = radial factor
Y = axial factor

Values for the factors X, Y are taken from the calculating procedure according to DIN ISO 281.

Static loadability
Under high static stresses, there develop on roller bearings and the roller bearing rollerways per-
manent deformations. Experience shows that a permanent total deformation of 0.00001 times
the diameter of the bearing at the central point of the most heavily-loaded contact point bet-
ween bearing and rollerway may be permitted in most applications without impairment of the
operating efficiency of the bearing. The static bearing figure is thus set so high that this defor-
mation occurs approximately when the equivalent static loading is equivalent to the static bea-
ring figure.

The static equivalent loading PO for ball bearings is a mathematical value which converts the exi-
sting radial and axial loadings on the ball bearing to a constantly-operative radial loading. The
static carrying figure CO is taken from the corresponding table in the ball bearing catalogue.

Po = Xo * Fr + Yo * Fa

Po = static equivalent loading

Fr = radial loading
Fa = axial loading
Xo = radial factor = 0.6 for ball bearings
Yo = axial factor = 0.5 for ball bearings

Values for the factors X, Y are taken from the calculating procedure according to DIN ISO 76.

32
Pre-stressed / bearing adjustment
In order to achieve operation as near noiseless as possible, in most applications, two ball bearings
are installed in contact with one another (pre-stressed). Pre-stressing is actually accomplished by
spring elements. The elastic nature of the pre-stressing equalises out temperature variations
during operation. In addition, vibration and stationery shocks are lessened.
Optimum pre-stressing must be calculated for each and every application. If pre-stressing is high,
there will be increased friction torque and an increase in temperature which will lead to a
decreased service life. On the other hand, if the pre-stressing is too low, this will lead to problems
with friction corrosion, fretting corrosion, vibration and thus to noisier operation. NMB Minebea
recommends that the pre-stressing is introduced over the non-rotating ring of the ball bearing
(inner or outer ring). This will prevent frictional corrosion occurring because of relative movement
between the rotating parts. The rotating ring should be fixed by a press-fit. For the majority of
applications, this means that with the shaft rotating the inner ring of the ball bearing will be
fixed with a press-fit. The pre-stressing should then be introduced over the outer ring with a
spring element, e.g. a three-pointed corrugated washer (see sketch).

33
 Preload
Optimum Preload

In most applications where ball bearings are used, an axial load is deliberately built in. This is
done for two reasons:
If there is any internal bearing clearance, vibration and noise will occur, and also axial and radial
yield rates will be very soft. This force applied in the axial direction is known as preload. An opti-
mum preload can be specified for each size of ball bearing. If too much preload is applied, the
bearing fatigue life will be short and bearing starting and running torque will also be high. If the
preload applied is insufficient, fretting corrosion can occur. This happens as a result of vibration
causing the balls to resonate on the track. Therefore, obtaining the correct Preload is very impor-
tant. Optimum preload is normally recommended after calculating the optimum operating sur-
face stress at the contact ellipse.

The contact ellipse is the area of contact between ball and raceway that occurs as a result of pla-
stic deformation of both parts under load. Operating surface stress is given by Q/S, where Q = ball
load or load on the raceway (perpendicular to the point oft contact), and S = surface area of the
contact ellipse. Please see figure A.

Depending on the life requirement for each application, the following guidelines can be applied.
If the life requirement is over 10,000 hours (e.g. Hard Disk Drives, etc.), the preload can be calcu-
lated based on an optimum surface contact stress that does not exceed 80 Kgf/mm^2.

For applications with a life requirement of between 5,000 and 10,000 hours, the optimum prelo-
ad can be calculated using a contact ellipse stress that does not exceed 100 Kgf/mm^2 (general
applications).

For applications requiring an operating life of less than 5,000 hours a surface stress of less than
150 Kgf/mm^2 should be used. (Mainly used in applications where high rigidity is required).

If a surface stress of 270 Kgf/mm^2 is applied in a high carbon chrome bearing, permanent race-
way and ball deformation will occur. It is possible that stresses below 270 Kgf/mm^2 will result in
no permanent raceway or ball deformation, but we would recommend a maximum safe working
stress of 160 Kgf/mm^2. Please contact NMB Minebea Engineering Department for further infor-
mation on this subject.

34
Preload and Stiffness
There are two basic methods of preloading: solid preload and spring preload.

Solid preload can be obtained by mechanically locking all of the rings in position whilst under an
axial load. The advantages of this type of design are that the components remain simple and the
stiffness is high. The disadvantage is high variation in preload under temperature variation. Also
the preload can reduce with wear.

Constant pressure preload (or spring preload) can be applied using a coil spring washer. An
advantage of constant pressure preload is that it sustains consistent preload with temperature
variation. A disadvantage is that the designs are more complex and normally have lower stiffn-
ess. The preload can be applied in two directions, DB and DF (DB = Duplex back to back, DF =
Duplex face to face). When considering stiffness, DB is more commonly used because it is stiffer
under moment loads.

35
 Fitting
A ball bearing is normally interference fitted or glued onto a shaft or into a housing. The inter-
ference fit or glue has an effect on the bearing performance, which is caused by reduction in radi-
al clearance. Radial clearance reduction is caused as a result of hoop stress on the inner/outer ring
which respectively causes expansion/contraction of the respective ring. In an interference fit, the
shaft/housing geometry will influence the shape of inner/outer ring. Glue can also induce the
same effects. This is caused as a result of accelerated localised expansion of the glue during
curing. These factors effect: bearing life, torque, rotational stability, non-repetitive radial run out
(NRRO) and noise.

Inner ring expansion can be calculated as follows:

Interference fitting a ball bearing on a shaft Interference fitting a bearing into a housing

The expansion of an inner ring caused by an interference fit of a ball bearing on a shaft, Δ,
is equivalent to the reduction of radial clearance in the ball bearing.

∂ = expansion of inner ring caused by interference fit

d = inner ring bore
d1 = bore diameter of shaft (if solid value is 0)
I = Fit
Eb = Young’s Modulus of elasticity (inner ring)
Es = Young’s Modulus of elasticity (shaft)
mb = Poisson’s ratio (inner ring)
ms = Poisson’s ratio (shaft)

The reduction of an outer ring caused by an interference fit of a ball bearing into a housing, Δ,
is equivalent to the reduction of radial clearance in the ball bearing.

Δ = compression of outer ring caused by interference fit

D1 = outer ring raceway diameter
D = outer ring outside diameter
D2 = housing outside diameter
I = fit
Eh = Young’s Modulus of elasticity (housing)
mh = Poisson’s ratio (housing)

36
Bearing Deflection, Yield Rates
and Natural Bearing Frequencies
An externally applied load on a ball bearing will cause a deformation at the raceway and
ball (known as yield), resulting in bearing deflection. The amount of deflection that has
occurred is very important in calculating yield rates and natural bearing frequencies.

Radial deflection

The figure below illustrates a force F applying

a maximum load Q to a single bearing ball.
Values of Q between two balls is calculated as follows:

The amount of deflection caused at the contact point

is calculated as follows:
δ=

Deflection occurs on both the inner ring and outer ring and can be
calculated as follows:

δt = δi = δe δt = total, δi = inner ring, δe = outer ring

37
 Bearing Deflection, Yield Rates
and Natural Bearing Frequencies

Axial deflection

When an axial load is applied to a ball bea-

ring, the axial deflection can be calculated as
follows:

Loaded contact angle

Relationship between free contact

angle and loaded contact angle

According to the above calculations, axial

deflection can be calculated as follows:

Cr = Radial clearance
c = Modulus of elasticity

38
Bearing Deflection, Yield Rates
and Natural Bearing Frequencies

Yield rate
When an external load is applied to a ball bearing, the ball can be considered as behaving like a
spring. The yield rate can be illustrated as follows and in accordance with calculations on page …
Plotting a graph of bearing deflection against load, a tangent can be drawn at a specified load
interval to derive the given yield rate.

Natural frequency
The natural frequency effects of ball bearings are becoming more and more important as motor
designs become smaller and smaller. The effects of vibration resulting in resonance of the ball
bearings’ natural frequencies mean that noise considerations have become critical at the stage of
ball bearing selection.

Natural frequency in axial direction

Variables that affect natural frequencies in ball bearings are:

W = Outer ring weight

G = Accelleration
k = Yield rate

Bearing noise
Often a ball bearing application requires low noise characteristics, for example VCR’s, office
equipment, fans and motors, etc.
It is extremely difficult to establish the noise characteristics of a ball bearing by simply taking
dimensional measurements. It is therefore essential to conduct a dynamic or functional noise
test.

39
 Vibration from rotation
The function of a ball bearing is to rotate quietly and smoothly with as little vibration as possi-
ble. However, when rotational and/or external vibrating frequencies are coincident with the
natural frequencies of component parts in assemblies, resonance is generated leading to excessi-
ve noise and vibration.
The natural vibration frequencies of a ball bearing alter with a change in the rotational speed.
Vibration has three directions, which are: axial, radial and rotational. The direction of vibration
can be critical, depending on the application, e.g. the performance characteristics of a VCR Drum
Motor are adversely affected by rotational and axial vibration. Also a laser scanner is adversely
affected by rotational vibration and hard disk drives are affected by radial vibration. The three
vibration directions can produce additional energy within the bearing components, inducing
resonance. NMB have established an excellent reputation for high accuracy and good quality
resulting in bearings with low vibration characteristics.

Calculating vibration frequencies

Inner ring rotation application @fr [Hz]
fa = Orbiting ball frequency (Rotation about the bearings axis of rotation)

fb = Retainer frequency (Same as fa, retainer and balls rotate at the same speed)
fb = fa
fc = Ball rotation frequency (Rotation about its own axis)

fd = Vibration caused by ball-pass a point frequency

fdt = (ball-pass-outer-raceway frequency/outer raceway defect)

fdr = (ball-pass-inner-raceway frequency/inner raceway defect)

Outer ring rotating applications @Fr [Hz]

Fa = Orbiting ball frequency (Rotation about the bearings axis of rotation)

Fb = Retainer frequency (Same as Fa, retainer and balls rotate at the same speed)

Fc = Ball rotation frequency (Rotation about its own axis)

Fd = Vibration caused by ball-pass a point frequency

Fdt = (ball-pass-outer-raceway frequency/outer raceway defect)

Fdr = (ball-pass-inner-raceway frequency/inner raceway defect)

Summary of variables:
DW = Ball diameter; Dpw = Pitch circle diameter; α0 = Nominal contact angle;
Z = Ball quantity; n = Integer;
40 fr = Inner ring rotational speed (Hz); Fr = Outer ring rotational speed (Hz);
cos α0 = ~1 (can be used for the purposes of this calculation)
Installation tolerances
Ball bearings are fixed, according to the external forces, in radial and axial direction on the shaft
and in the housing. The fixing may be achieved either by means of press-fit, bonding, or by
shape-fit (safety washers or safety discs).

Operationally-dependent heat expansion of various types of shafts and motor components will
lead to inner stresses on the bearing system if neither of the ball bearings is allowed to move,
(loose bearing).

As a general rule, the rotating ring of the ball bearing will be provided with a fixed seating. ISO
5425 gives instructions regarding the bearing fixing and degree of accuracy of the adjustment. In
the case of thin-walled ball-bearings, the ISO details should not simply be followed. We will be
happy to advise you on the ideal choice of installation tolerances and fixing the bearings.

Handling ball bearings

Ball bearings are precision components and a great deal of care and technology goes into ensu-
ring that their manufacture and packaging meet high standards of cleanliness. Moisture, particles
of dirt, metal filings and other foreign bodies, once they penetrate the bearing, can substantial-
ly affect the running qualities, silent running behaviour and the service life of a bearing. For this
reason, ball bearings must be treated correspondingly carefully in their use.

It is essential that the following points are observed:

– Leave the bearing in its original packaging
until it is time to use it - it is not a waste-basket!
– After removing of the required quantity of ball bearings, reseal the original packaging
– Keep the installation location clean - no chips, filings, dust etc.
– Bearing seatings must be clean and free of swarf, etc.
– Check assembly tools regularly
– Only use force on the ring to be installed
– Do not lay the bearings on highly-absorptive surfaces
– Do not blow the bearing clean with compressed air
– Use no chemicals in the vicinity (gases, vapours, liquids)

When using adhesives, problems with endurance of the lubricant may sometimes occur. This rela-
tes particularly to products which contain cyano-acrylates.

41
 Mechanical components
As the world’s largest manufacturer of miniature ball bearings, it is appropriate that we should
also manufacture ball bearing components with the highest precision. NMB Minebea manufact-
ures such components on state-of-the-art manufacturing equipment. Planning, manufacturing
and testing procedures are all carried out in house by ourselves. For example, all tools, turned and
moulded parts are manufactured in house. Assembly of the mechanical components is all under-
taken in clean rooms which meet the most exacting standards of cleanliness.

42
Mechanical components (assemblies)
Since mechanical components are always developed and manufactured for one specific customer,
close contact with the customer is an absolute essential for carrying out the project successfully.
That there is intensive co-operation between the application engineers and sales engineers of
NMB Minebea and the customer really goes without saying.

Primarily, small and very precise components are manufactured for all applications. Thus you will
find shaft encoders, roller conveyors, injection-moulded impellers and components for the PC and
automation industry in the NMB Minebea product range.
NMB Minebea’s production capacity makes it possible for us to take on the manufacture of both
small orders and large series with major production quantities.

43
 Engineering support
It is NMB Minebea’s aim to give its customers optimal support right through the project phase
and series production. To this end, our sales and applications engineers offer you the service at
your premises. You will continue to receive individual answers to all organisational and commer-
cial questions from your local NMB Minebea office. Alongside the usual services such as provision
of quotations, sampling, service life calculations and preparation of drawings, we also support
our customers in the new developments sector with ball bearing analysis available during or after
the field trials.

Assessment and report preparation is carried out in our German Headquarters in Langen. This is
the location of our central ball bearing laboratory for Europe, which is equipped with the most
important analysis equipment and measuring devices. This guarantees very quick and flexible
turnaround of the analysis. For detailed material and lubricant analysis, we have available the
development centres of NMB Minebea around the world, in Japan, Thailand, Singapore and USA.

By arrangement with our customers, we can carry out preliminary tests or endurance tests on our
own test benches. For this purpose, our Germany location is equipped with modern test benches
which also means individual field trails can be carried out.

Naturally enough, we also support our customers in investigating failures, or manufacturing pro-
blems. In close co-operation with our engineers, manufacturing analysis is often a decisive factor
in early recognition of problems and avoiding later failures.

Training measures covering the whole subject of ball bearings - either at one of our facilities or
directly at the customer’s premises - round off the range of services which we offer.

44
Sample copy for request form · Fax to: +49 (0) 6103 913 328
Company Date
Street/No. Factory
Town/Postcode Telefon
Name/Department Fax
Your parts No./project name
Application/details
Annual needs Stk./Jahr Start of series production
Service life product No. of bearings/application
NMB part numbers
If NMB part unknown, please complete the following fields and/or enclose data sheet/drawing
Material Chrome steel Stainless steel Hybrid bearing
Bore ø mm Cover disc Flange bearing Flange ø mm
Outer ø mm Sealing disc Flange width mm
Width mm Open Radiale clearance from to µm
Tolerance class Lubricant
Rotation speed Usual service life h. Inner ring rotation Outer ring rotation
Rotation type Continuous Reversing Oscillating Oscillating angle
Temperature range Working temp.
From °C To °C °C Dust Humidity %
FR N F1A N
FA N F1R N
Fi N F2A N
a mm F2R N
b mm Continual
c mm Shock
Pre-stressing N
Acts on Inner ring
Outer ring
Shaft material Roughness Rz/Ra µm tolerance
Housing material Roughnes Rz/Ra µm tolerance
Shaf /bearing fit House/bearing fit
Force fit Force fit Sketch: please sketch shaft, housing and
Sliding fit Sliding fit securing elements or springs etc., drawings if appropriate.

45
 Notes

46
Notes

47
 Our products:

Ventilators and blowers

Controllers

Articulated
and spherical bearings

Geared motors

Stepper motors

Brushless DC motors

Loudspeakers

Loudspeaker boxes

PC keyboards

NMB Minebea U.K. Ltd.

Bearing & Airmover Sales
Suite 2.2, Doncastle House, Doncastle Road,
Bracknell, Berkshire RG12 8PE, U.K.
Tel. +44 (0) 1344-426 611 Fax +44 (0) 1344-485 522

NMB Minebea SARL

5, Avenue Des Bosquets, Les Ponts De Baillet
95560 Baillet en France, France
Tel. +33 (0) 1-34 083 939, Fax +33 (0) 1-34 083 930

NMB Minebea Italia S.R.L.

Via A. Grandi, 39/41, 20017 Mazzo di Rho (MI), Italy
tel. +39 02-9397 11 Fax +39 02-9390 11 54

www.nmb-europe.com
Issue 2 January 2008

NMB Minebea GmbH

Siemensstr. 30· D-63225 Langen · Germany
Tel. +49 (0) 6103 913 0 · Fax +49 (0) 6103 913 328
email: info_de@nmb-minebea.com
www.nmb-minebea.de