GB/T 25764-2024Rolling bearings - Roller bearings for automotive transmissions (English PDF)

8.2.1 Bearing tolerance

8.2.1.1 The tolerance of the bearing shall not be lower than the provisions of the ordinary grade tolerance in GB/T 307.1-2017.

8.2.1.2 The tolerance of the outer diameter Ew of the roller set of RN and RND cylindrical roller bearings shall be .

8.12 Appearance quality The working surface of the bearing shall not have cracks, rust, obvious bumps.

8.13 Life

8.13.1 After the conventional life test of the bearing, the ratio -- of the test value of its rated life to the basic rated life L10 t/L10 h shall not be less than 2. If the user has special requirements, it can also be determined by negotiation with the manufacturer.

8.13.2 The life of the bearing bench simulation test shall meet the requirements of the corresponding vehicle model.

8.13.3 The durability life of the actual vehicle bearing shall meet the requirements of the corresponding vehicle model.

8.14 Others

8.14.1 The technical conditions of the matching between shaft and the bearing seat and the bearing hole are shown in Appendix A.

8.14.2 Other technical requirements shall comply with the provisions of GB/T 307.3- 2017 and JB/T 10336-2017.

8.14.3 When the user has other requirements for the bearing, it can be negotiated with the manufacturer.

9.2 Inspection of roller sag

9.2.1 The roller sag can be replaced by the maximum and minimum values of the inner and outer diameters of the roller group with a stop gauge before the bearing is assembled.

9.2.2 For cylindrical roller bearings without outer rings or with detachable outer rings,

9.3 Chamfer detection The chamfer detection method shall comply with the provisions of GB/T 307.2-2005.

9.4 Measurement of rolling surface shape The measurement method of the rolling surface shape of the bearing can refer to the measurement method of the crowned roller in GB/T 4661-2015.

9.5 Measurement of surface roughness The measurement method of the bearing surface roughness shall comply with the provisions of JB/T 7051-2006.

9.6 Measurement of clearance

9.6.1 Radial clearance The measurement method of the radial clearance of the bearing shall comply with the provisions of GB/T 25769-2010.

9.6.2 Axial clearance

9.6.2.1 The measurement of the axial clearance of the NUP cylindrical roller bearing is shown in Figure 18. During the measurement, the end face of the outer ring of the bearing is pressed tightly; then the measuring load Q (100 N) is alternately applied to the inner ring of the bearing with uniform force, so that the inner ring of the bearing moves up and down along the loading direction. The difference between the average values of the two positions read from the indicator is the axial clearance value.

9.6.2.2 The measurement method of the axial clearance of double-row tapered roller bearings shall comply with the provisions of

JB/T 8236-2023, or according to the user's requirements. the plug gauge to keep it still; rotate the ring gauge for several cycles; check the rotation flexibility of the bearing.

9.11.5 HKN type bearings First press the bearing into the ring gauge (ring gauge size = bearing outer diameter D - N6 lower deviation value); then insert the plug gauge (plug gauge size = Fw lower deviation value -

0.015 mm) into the bearing (already pressed into the ring gauge), so that the axis of the bearing (together with the ring gauge and plug gauge) is in the horizontal direction; fix the plug gauge to keep it still; rotate the ring gauge for several cycles; check the rotation flexibility of the bearing. 9.11.6 30000, R 30000, 350000 R type bearings Support the back of the inner ring of the bearing; keep the inner ring of the bearing still; rotate the outer ring (R 30000 type bearing is the standard outer ring) for several cycles; check the rotation flexibility of the bearing.

9.12 Inspection of appearance quality Visually inspect under a diffuse light or use special equipment to inspect.

9.13 Life test

9.13.1 The bearing fatigue life test method shall comply with the provisions of GB/T 24607-2023.

9.13.2 The bearing gearbox bench simulation life test shall comply with the user's requirements.

9.13.3 The bearing actual vehicle endurance life test shall comply with the user's requirements.