Single direction tapered roller thrust bearings
The small single direction tapered roller thrust bearings are used almost exclusively for the kingpin bearing arrangement of commercial vehicles (fig 1). They have a full complement of rollers and are held together by a sheet steel cover (fig 2). Most of these bearings are fitted with rubbing seals of wear and oil-resistant nitrile (NBR) rubber (fig 3). They are lubricated for life with a multi-purpose grease and require no maintenance. There are several designs which differ only in the design of the housing washer and the cover (fig 4).
The larger single direction bearings differ in the execution of the washers; some have dimensionally identical shaft and housing washers (fig 5) and some have washers of different design (fig 6).
The washers of the bearings with shaft and housing washers having the same dimensions (fig 7) both have a tapered raceway and one retaining flange. Bearings of this design are to be preferred where very heavy axial loads are to be supported as, for example, in the swivels of drilling rigs or in crane hooks. The bearings have a cage which is centred on both washers.
Bearings of the other design (fig 8) have a shaft washer with tapered raceway and retaining flange whilst the housing washer is plane (flat). Therefore, bearings of this design are able to accept minor eccentricities of the shaft with respect to the housing bore without any detrimental influence on bearing performance. With the exception of a few sizes which have a full complement of rollers, the bearings are fitted with a roller centred cage.