ZWZ KOYO SKF slewing bearing

(1). Flat-race thrust bearings:
Consist of a pair of flat washers separated by the ball complement and a shaft-piloted retainer, so load capacity is limited. Contact stresses are high and torque resistance is low. The prime advantage of flat-race thrust bearings is they permit eccentricities, because there are no grooves to restrain one race from wandering slightly with respect to the other.
(2). One-directional, grooved-race thrust bearings:
(3). Two-directional, grooved-race thrust bearings:
It consist of two stationary races, one rotating race, and two ball complements. Thrust bearing characteristics are identical to those of the one-directional bearing, except thrust bearings can support thrust in both directions.