Double direction tapered roller thrust bearings
Tapered roller thrust bearings of the double direction type are mainly used together with multi-row cylindrical roller bearings in rolling mill applications (fig 1). Those bearings with a plane shaft washer (fig 2) are the more popular as they are able to accommodate slight eccentricities of the shaft with respect to the housing bore, of the order of the radial internal clearance of the radial bearing with which they are used. A spacer sleeve is arranged between the two housing washers. This is dimensioned so that the cover screws of the chock can be fully tightened and no special spring adjustment of the bearing is required.
The double direction tapered roller thrust bearings with tapered raceways on the shaft and housing washers (fig 3) generally have a higher axial load carrying capacity than the bearings with a plane shaft washer and are able to radially locate the shaft to a certain extent. If the load carrying capacity of these bearings is inadequate with respect to the requisite life, double row tapered roller bearings with large contact angle of the TDIS design can be used instead, see under Double row tapered roller bearings.
As double direction tapered roller thrust bearings are usually mounted with a loose fit on the roll neck as well as in the chock, the shaft washer of most bearings has one or two locating slots. It is then possible to prevent the shaft washer from rotating on its seat by using keys which engage the slots, or by similar means.