51201 Thrust Bearing.
A thrust bearing is a particular type of rotary bearing. These bearings consist of three parts, a shaft and housing washer which have annular grooves machined into them and a caged ball bearing assembly which is sandwiched between the two washers. Assembly and mounting is quite simple as the parts are able to be separated. Thrust bearings are able to accommodate axial loads in a single direction only and must not be subject to any radial load. Clearance is provided in the bore of one of the raceways to allow for alignment.