Introduction of Cam Follower Needle Bearing
While roller cam followers are similar to roller bearings, there are quite a few differences. Standard ball and roller bearings are designed to be pressed into a rigid housing, which provides circumferential support. This keeps the outer race from deforming, so the race cross-section is relatively thin. In the case of cam followers the outer race is loaded at a single point, so the outer race needs a thicker cross-section to reduce deformation. However, in order to facilitate this roller diameter must be decreased, which also decreases the dynamic bearing capacity.
End plates are used to contain the needles or bearing axially. On stud style followers one of the end plates is integrated into the inner race/stud; the other is pressed onto the stud up to a shoulder on the inner race. The inner race is induction hardened so that the stud remains soft if modifications need to be made. On yoke style followers the end plates are penned or pressed onto the inner race or liquid metal injected onto the inner race. The inner race is either induction hardened or through hardened.
Another difference is that a lubrication hole is provided to re-lubricate the follower periodically. A hole is provided at both ends of the stud for lubrication. They also usually have a black oxide finish to help reduce corrosion.