Precise combination bearing with adjustable pretightening force

According to the technical scheme, the pretightening force adjustable precise combination bearing comprises a bearing outer ring, a bearing inner ring is coaxially arranged on the inner side of the bearing outer ring, a plurality of balls are arranged between the bearing outer ring and the bearing inner ring and distributed in a circumferential array mode, retainers are arranged on the two sides between the bearing outer ring and the bearing inner ring, and the retainers are arranged on the two sides between the bearing outer ring and the bearing inner ring. The precise combination bearing with the adjustable pretightening force has the beneficial effects that the pretightening adjusting mechanism is arranged, the adjusting bolt is limited through the locking nut, so that the spacing distance between the two retainers can be adjusted, and the pretightening force is adjusted through elastic extrusion of the first spring, so that the pretightening force is adjusted, and the precision of the pretightening force is improved. According to the retainer for the ball bearing, by arranging the arc-shaped plates, every two opposite arc-shaped plates can clamp the balls to different degrees, so that pre-tightening force adjustment is achieved, and the problems that the pre-tightening force of an existing retainer for the ball bearing is fixed during installation, adjustment cannot be conducted according to the sizes of the balls or actual situation needs, and use is inconvenient during combination and assembly are effectively solved.