For roller bearings, it is necessary to consider the contact stress between the end face of the roller and the retaining edge, which can be calculated by the relevant formula. One of the most common design methods of roller bearings is that the end face of the roller is flat. There will be an arc chamfer at the point where it is connected with the salient part of the shape of the roll, and the edge can also be a part of the plane.

However, when the thrust load is required between the end face of the roller and the retaining edge of the roller bearing, sometimes the retaining edge is designed as a conical surface. In this case, the chamfer of the roller will contact the retaining edge, and the angle between the retaining edge and the radial plane is called the retaining edge inclination.

In addition, the roller face of roller bearing can also be designed as a spherical surface, so that the spherical end of the roller contacts with the oblique shield. This structure helps to improve lubrication, but reduces the guiding ability of the shield to the roller. In this case, the cage must be used to control the rollers'deflection to ensure the normal operation of the bearings.

For the convenience of calculation, it can be assumed that the radius of the sphere is equal to the radius of the end surface of the roller sphere, while the radius of the cylinder can be approximated by the radius of curvature of the conical edge at the theoretical contact point. The contact stress and deformation can be calculated according to the known elastic contact load, rollers, material characteristics of the retaining edge and contact geometric parameters.

But this method can only be approximate to calculate the contact stress between the roller end face and the retaining edge of roller bearing, because the liquid end face and the retaining edge do not satisfy the assumption of half space. In addition, the curvature radius of the tapered baffle is not constant, but varies along the contact width. So this method can only be applied to the contact between the whole spherical liquid end face and the conical baffle.