Hydraulic power transmission joint which is used in vehicles

Abstract

Two rotary shafts for transmitting power are coupled so as to be relatively rotatable. When a rotational speed difference occurs between the two shafts, a torque corresponding to the rotational speed difference is hydraulically generated and is transmitted from the shaft of the higher rotational speed to the shaft of the lower rotational speed. A cam surface having two or more cam mountains is formed on the inside edge surface of the cam housing. A rotor is assembled in the cam housing so as to be relatively rotatable. The rotor faces the cam surface and is formed with a plurality of plunger chambers in the axial direction. Plungers are movably assembled in the plunger chamber through return springs. The plunger chambers are connected to the high pressure chamber through delivery passages having delivery valves. The plunger chambers are communicated with the low pressure chamber through suction passages having suction valves and oil circulating grooves formed in the axial direction of the rotor outer peripheral surface. A throttle mechanism operated by an increase in oil temperature and in pressure in the high pressure chamber is arranged between the high and low pressure chambers. A variable orifice mechanism whose orifice cross sectional area changes with an increase in delivery pressure may also be provided in place of the throttle mechanism.