Development of tapered roller bearing with low torque: Reduction of sliding friction between large flange and roller end faces machined by precision powder shot peening

A taper roller bearing can support both radial and axial loads and is available for the differential gear mechanism of a vehicle. Since the inner and outer rings can be separated, the axial force should be loaded to some extent as preload even if the bearing is used for supporting the radial load. However, when the axial force is loaded, the rotational torque becomes larger owing to the sliding friction between the roller end face and the large flange surface of the inner ring. In this research, to reduce the sliding friction inside the taper roller bearing, precision powder shot peening was performed on the large flange surface of the inner ring. Thus the bearing torque was reduced considerably by increasing the surface hardness and residual compressive stress and by smoothing the surface protrusion by grinding Shot Machine A. one Polish treatment. Furthermore, it was confirmed that the wear of the taper roller end face was the same as before and that of the large flange surface could be inhibited.