Rotary fluid pressure device and improved shuttle arrangement therefor

摘要

A gerotor motor (11) of the valve-in in-star type is provided wherein a stationary valve member (17) is disposed immediately adjacent the gerotor gear set (19). The stationary valve member defines a shuttle bore (81) and disposed therein is a shuttle member (107) which moves between two operating positions (FIGS. 6 and 7) under the influence of system pressure. The shuttle valve member (107) communicates system pressure from whichever of the ports (39 or 41) is at high pressure to a pressure balancing recess (63). At the same time, the shuttle valve (107) provides fluid communication between whichever of the ports is at low pressure and a low pressure passage (83) which may be in communication with a lubrication circuit (95), or may be in communication with a case drain port, to divert a small amount of fluid to a heat exchanger. The invention provides a very small shuttle valve arrangement comprising only a single part, and eliminating a substantial amount of the machining previously required in the motor endcap (15).