One / Two Direction Grooved Race Thrust Ball Bearing 51100-51120, 51305-51320, 51405-51420
(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.
It have grooved races very similar to those in radial bearings. Thrust bearing capacity is about twice that of the flat-race bearing and limiting speed is about three times as high. However, a thrust bearing has a limiting speed, which is still quite low because balls spin at high speeds.
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.