BW-13231 GCr15 Centrifugal One Way Sprag Clutch Bearing

              BW-13231 GCr15 Centrifugal One Way Sprag Clutch Bearing

Sprag lift-off X

Internal Freewheels FXN are equipped with sprag lift-off X. The sprag lift-off X is used for backstops and overrunning clutches, provided that in freewheeling operation the inner ring is rotating at high speed and providing with overrunning clutches that the driving operation is conducted at low speed. In freewheeling operation, the centrifugal force F C causes the sprag to lift off from the outer track. In this operating state, the freewheel works wear-free,i.e. with unlimited service life.

Figure 76-2 shows a freewheel with sprag lift-off X in freewheeling operation. The sprags,which are supported in a cage connected with the inner ring, rotate with the inner ring. Thecentrifugal force F C that is applied in the center of gravity S of the sprag turns the sprag coun-terclockwiseand rests against the support ring of the cage. This results in the gap a between the sprag and the outer track; the freewheel works with out contact. If the inner ring speed decreases to such an extent that the effect of the centrifugal force on the sprag is less than that of the spring force FF , the sprag again rests on the outer ring and the freewheel is ready to lock (figure 76-3). If used as an overrunning clutch, the driving speed must not exceed 40% of the lift-off speed.

Dimension and Capacity

Pictures