Tolerance and wear compensating friction clutch

Abstract

A clutch structure is provided that automatically compensates for manufacturing or part-to-part tolerance variations in new clutches and that continuously compensates for wear of interleaved clutch plates throughout the life of the clutch. The clutch includes an actuator, preferably a fluid piston, that compresses the clutch plates to engage the clutch and transmit power between two rotating elements. An adjustment ring, fitted to an actuating ring, is contacted by a portion of the piston and is displaced against the force of a biasing spring during engagement of the clutch. Abutment members limit movement of the actuating ring, permitting the piston to displace the adjustment ring unidirectionally on the actuating ring during full engagement of the clutch. Upon disengagement of the clutch, the biasing spring urges the actuating ring, and with it the adjustment ring, back to its disengaged position. The adjustment ring thereby urges the piston to a reference disengaged position. The reference position may be displaced in the direction of the clutch plates as the clutch plates wear, thus providing consistent and uniform engagement and clutch performance over the life of the clutch. The actuating ring preferably covers a fluid passage when the clutch is disengaged, and uncovers the passage by its displacement when the clutch is engaged. Cooling or lubricating fluid is thus admitted into the clutch only upon engagement and fluid flow through the passage is reduced or interrupted upon disengagement.