Patent ID: 6679691
Filing Date: 2004-01-20
Classification: F04C

Abstract:
A fluid pressure operated device comprising housing means defining a fluid inlet port and a fluid outlet port; a fluid pressure displacement mechanism associated with said housing means, and including a stationary member and a rotating member operably associated with said stationary member, said stationary member and said rotating member having relative movement to define a plurality N of expanding and contracting fluid volume chambers in response to said relative movement; motor valve means cooperating with said housing means to provide fluid communication between said fluid inlet port and said expanding volume chambers, and between said contracting volume chambers and said fluid outlet port in a normal low-speed, high-torque mode of operation; shift valve means operable, in a first condition, to permit said normal low-speed, high torque mode of operation and, in a second condition, to interconnect a plurality M of said volume chambers, said plurality M comprising recirculating volume chambers; said fluid pressure operated device being characterized by:(a) said device defining a supplemental fluid passage operable to provide fluid communication from a source of pressurized fluid to each of said plurality M of recirculating volume chambers; and (b) control valve means operable, in a normal mode, to block fluid communication from said source of pressurized fluid to said supplemental fluid passage, and in a shift mode, to permit fluid communication from said source of pressurized fluid to said supplemental fluid passage.