Control valve mechanism for hydraulic clutch in a power transmission mechanism

A clutch capacity control valve system for controlling engagement of a pressure operated clutch comprising a fluid pressure feed passage for said clutch, a pressure regulator valve in said passage for modulating the pressure made available to said clutch, said valve comprising a valve chamber, a regulating valve spool having spaced valve lands, a first port and a second port communicating with said valve chamber at locations intermediate said valve element lands, a bypass passage extending from one portion of said valve chamber to one side of said valve element, spring means acting on said one side of said valve element tending to move the latter to a passage open position which establishes relatively free communication between said ports, one valve land registering with one port to establish restricted fluid communication between said ports, an exhaust port registering with the other valve land whereby said valve element regulates the pressure made available to said clutch when the pressure force action thereon overcomes the force of said springs, an orifice means in said bypass for establishing restricted flow from said clutch feed pressure line to said valve chamber on said one side of said valve element, an accumulator comprising an accumulator chamber in fluid communication with said valve chamber on said one side of said valve element, an accumulator piston in said accumulator chamber having a pressure area thereon that is subjected to the pressure in said valve chamber on said one side of said valve element and an accumulator valve spring opposing the pressure force acting on said accumulator piston, said accumulator including means for distributing a torque sensitive pressure signal to said accumulator chamber whereby a pressure force proportional to torque is developed on said accumulator piston to supplement the force of said accumulator spring.