Design of bearing arrangements
Abutment dimensionsThe support surfaces on shafts and in housings should be at right angles to the shaft or housing axis and should provide uninterrupted support over the entire washer face. The abutment diameter on the shaft should be ≤ Ea and in the housing ≥ Eb. Values for Ea and Eb (→ product tables) take the movement and position of the roller set into consideration.
To provide satisfactory radial guidance for the individual thrust bearing components, suitable tolerance classes for shafts and housings are listed in table 1. Radial space between the shaft and washer bore is required for housing centred washers. Shaft centred washers require radial space between the washer and housing bore.
Needle roller and cage thrust assemblies in the AXW series are generally combined with drawn cup needle roller bearings (fig. 1) or needle roller bearings with machined rings (fig. 2). The same housing tolerance must be selected for the centring flange as for the radial bearing.
Needle roller and cage thrust assemblies are generally shaft centred, to reduce the circumferential speed at which the cage slides against the guiding surface. This is particularly important for higher speed applications. The guiding surface should be ground.
Raceways on shafts and in housingsIf the load carrying capacity of a needle roller and cage thrust assembly is to be fully exploited, the raceways on the shaft or in the housing should have the same hardness, surface finish and axial run-out as a bearing washer.
The dimensions Ea and Eb (→ product tables) take displacement of the roller set into consideration and should be applied when designing raceways on shafts and in housings.
For additional information, refer to Raceways on shafts and in housings.