CLUTCHES

摘要

A clutch includes two rotary shafts, one of which (2) is connected to one or more first clutch plates (8) which cooperate with a second set of clutch plates (10), the clutch plates being acted on by an actuating piston (12) having a portion exposed on two opposite sides to first and second chambers (16, 18) in a hydraulic cylinder. A torque control valve is provided comprising a cylindrical inner valve member (48) rotatably and linearly movably received in a cylindrical opening in an outer valve member (46), the inner and outer valve members affording cooperating cylindrical surfaces, in one of which an elongate first recess (64) is formed, which communicates with one of the chambers (16), and in the other of which two circumferentially spaced elongate second recesses (56, 54) are formed communicating with a source of pressurised hydraulic fluid (26) and a substantially unpressurised hydraulic reservoir (30), respectively. The elongate recesses (64, 56, 54) extend in the longitudinal direction and in the same circumferential direction in the cylindrical surface in which they are formed and are positioned such that longitudinal movement of the inner valve member (48) within the outer valve member (46) will vary the degree of communication between the first and second elongate recesses. The second clutch plates (10) are connected to one side of a spring (82) of predetermined spring rate, which is also connected to one of the valve members, and the other side of the spring is connected to the other of the valve members and to the other rotary shaft (4).