Glossary
Inner ring
Innenring
The inner ring is the bearing ring mounted on the shaft; its outer surface carries the hardened, precision-finished raceway, while the bore forms the shaft seat. It is usually made of through-hardened bearing steel such as 100Cr6 and toleranced to ISO 492. In most applications it rotates with the shaft and therefore sees circumferential load, so it is mounted with an interference fit to prevent creeping and fretting corrosion. Mounting forces must be applied to the inner ring only, never through the rolling elements, and the fit must be chosen together with the internal clearance, since interference reduces radial play.