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BEARING TOLERANCES

Table 8.10 Tolerances for Tapered Bores (Class Normal)

Nominal Tapered Bore Tapered Bore with Deviation in Single Plane Taper 1 : 30
Mean Bore Diameter
& d 1mp –jd mp Units : μ m
2
Nominal Bore Diameter & dmp -& d1mp & dmp Vdp (1) (2)

d max.
22
(mm) 40
46
over incl. high low high low
52
αα j(d1 + & d1mp) 80 120 +20 0 +35 0 57
120 180 +25 0 +40 0 63
180 250 +30 0 +46 0
70
jd jd1 250 315 +35 0 +52 0
j(d + & dmp) 315 400 +40 0 +57 0
400 500 +45 0 +63 0

500 630 +50 0 +70 0

Notes (1) Applicable to all radial planes of tapered bores.
(2) Not applicable to diameter series 7 and 8.

Remarks For a value exceeding 630 mm, please contact NSK.

BB 8.2 Selection of Accuracy Classes

d : Nominal Bore Diameter For general applications, Class Normal tolerances are
adequate in nearly all cases for satisfactory
d1 : Theoretical Diameter of Larger End of Tapered Bore performance, but for the following applications,
bearings having an accuracy class of 5,4 or higher
Taper 1:12 d1 = d + 1/12 B Taper 1:30 d1 = d + /30 B are more suitable.
For reference, in Table 8.11, examples of applications
& dmp : Single Plane Mean Bore Diameter Deviation in Theoretical Diameter of Smaller End of Bore and appropriate tolerance classes are listed for various
bearing requirements and operating conditions.
& d1mp : Single Plane Mean Bore Diameter Deviation in Theoretical Diameter of Larger End of Bore

V d p : Bore diameter variation in a single radial plane

B : Nominal Inner Ring width

α : Half of Taper Angle of Tapered Bore

Taper 1:12 Taper 1:30 Table 8. 11 Typical Tolerance Classes for Specific Applications (Reference)

α =2°23´9.4 α =57´17.4 Bearing Requirement, Examples of Applications Tolerance Classes
Operating Conditions
=2.38594° =0.95484° P5
P5, P4, P2
=0.041643 rad =0.016665 rad P5, P4, P2
P5
Taper 1 : 12 VTR Drum Spindles P5, P4

Units : μm }Magnetic Disk Spindles for Higher than P4

Nominal Bore Diameter & dmp -& d1mp & dmp Vdp (1) (2) High running accuracy Computers Higher than P4
is required Machine-Tool Main Spindles
d max. Rotary Printing Presses

(mm) 13 }Rotary Tables of Vertical
16
over incl. high low high low 19 Presses, etc.

18 30 +33 0 +21 0 22 }Roll Necks of Cold Rolling
30 50 +39 0 +25 0 40
50 80 +46 0 +30 0 46 Mill Backup Rolls

80 0 52 }Slewing Bearings for Parabolic
120 0 57
180 0 63 Antennas

250 120 +54 0 +35 0 70 Dental Drills CLASS 7P, CLASS 5P
315 180 +63 0 +40 0 Gyroscopes CLASS 7P, P4
400 250 +72 0 +46 0 - High Frequency Spindles CLASS 7P, P4
- Superchargers P5, P4
500 315 +81 0 +52 0 - Extra high speed is Centrifugal Separators P5, P4
630 400 +89 0 +57 0 - required Main Shafts of Jet Engines Higher than P4
800 500 +97 0 +63 0

1 000 630 +110 0 +70 0
1 250 800 +125 0 +80 0
+140 +90
Notes 1 000 0

1 250 +165 0 +105 Low torque and low Gyroscope Gimbals CLASS 7P, P4
1 600 +195 0 +125 torque variation are Servomechanisms CLASS 7P, CLASS 5P
required Potentiometric Controllers CLASS 7P
(1) Applicable to all radial planes of tapered bores.
(2) Not applicable to diameter series 7 and 8.

A 80 A 81