Patent ID: 7216482

Claim:
A hydrostatic continuously variable transmission comprising: a fluid pump and a fluid motor linked together in a closed circuit, wherein the capacity of at least one of the pump or the motor is variable to enable control of the relative rotational speeds of a pump input and a motor output, wherein the pump is a hydraulic pump, the motor is a hydraulic motor, and the fluid is a hydraulic fluid, a clutch device for engaging or disengaging force transmission between the pump and the motor, the clutch comprising: a clutch valve that can be opened to connect a high pressure fluid passage with a low pressure fluid passage of the closed circuit, or closed to disconnect the high pressure fluid passage from the low pressure fluid passage of the closed circuit; a mechanism constructed to generate a force in a closing direction of the clutch valve in response to the rotational speed of the pump input, wherein the mechanism constructed to generate a force in the closing direction is actuated by centrifugal force generated by the input rotation; a mechanism constructed to dampen the opening and closing of the clutch valve, wherein the clutch valve includes a valve spool that is movably arranged in a spool hole formed in the axial direction of a support shaft.