Patent ID: 8070364

Claim:
A roller bearing comprising: at least one first rolling part of a ceramic material having a first contact surface; at least one second cooperating rolling part comprising steel with a martensitic microstructure and having a second contact surface, at least a portion of the second contact surface configured and positioned to make rolling contact with the first surface; and the microstructure having residual compressive stresses beneath at least a portion of the second contact surface at least in a load-free state, wherein a level of the residual compressive stresses of an entire region starting from the second surface down to a depth of 40 Î¼m corresponds at least to an absolute value of 300 MPa, wherein the residual stresses decrease in magnitude below the depth of 40 Î¼m, and wherein the second rolling part includes a thermochemically produced outer layer to include the second contact surface, and the second contact surface is fully machined, wherein the thermochemically produced outer layer is nitrogen-enriched, wherein the outer layer of the second rolling part, at least at the second surface, has a hardness of at least 850 HV0.3 at a depth of 0.05 mm below the second surface, wherein the outer layer has been heat-treated twice, and the second heat treatment is at a process temperature of at least 400Â° C.