Raceways on Shafts and in Housings

Raceways machined in associated components for cylindrical roller bearings with only one ring and for cylindrical roller and cage thrust assemblies, must have a hardness of between 58 and 64 HRC if the load carrying capacity of the bearing or assembly is to be fully exploited.

The surface roughness should be Ra = 0,2 �m or Rz = 1 �m. For less demanding applications, lower hardness and rougher surfaces may be used.

The out-of-round and deviation from cylindrical form must not exceed 25 and 50%, respectively, of the actual diameter tolerance of the raceway.

The permissible axial runouts of raceways for thrust assemblies are the same as for the shaft and housing washers of thrust bearings, shown in table.

Suitable materials for the raceways include steel for through-hardening, e.g. 100Cr6 to ISO 683-17:1999, steels for case-hardening, e.g. 20Cr3 or 17MnCr5 to ISO 683-17:1999) as well as steels for induction-hardening that can be partially hardened.

The case depth that is recommended for raceways machined in associated components depends on various factors including the dynamic and static load ratios (P/C and P0/C0 respectively) as well as the core hardness, and it is difficult to generalize. For example, under conditions of purely static load up to the magnitude of the basic static load rating and with a core hardness of 350 HV, the recommended case depth is in the order of 0,1 times the rolling element diameter. Smaller case depths are permitted for dynamic loads. For additional information, please consult the SKF application engineering service.