An overrunning clutch includes an actuating ring to displace sprags from the race surfaces in the overrunning mode to reduce sprag wear. The actuating ring is positioned in the radial space between the inner and outer races and is cooperative with the sprag retainer to lift the sprags from engagement with the race surfaces in the overrunning mode. In a first embodiment, an actuating ring carries a plurality of circumference distributed tilt pads which are spaced axially from the sprags. Each tilt pad is pivotally mounted on the actuating ring and includes a shoe portion. The rotation of the inner race causes the shoe portion to experience hydrodynamic drag against the lubricant on the inner race surface. The drag tends to displace the ring relative to the sprag retainer and thereby contact the sprags and pivot them out of surface contact with the inner race. In a second embodiment, the actuating ring takes the form of a sleeve bushing with recesses formed in the inner radial surface. The recesses trap lubricant and create a fluid drag with the inner race surface at relatively high RPM. Again, the drag tends to displace the bushing relative to the sprag retainer and contact the sprags to lift them from the inner race surface in the overrunning mode.
展开▼