Abstract: 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.

Abstract: A gerotor motor is disclosed of the type including a stationary, internally-toothed ring member (21;221) and an externally-toothed star member (23;223) orbiting and rotating within the ring member. The motor is of the type utilizing a valving member (53;253) of the "low-speed" type, which rotates at the speed of rotation of the star member. The star member defines internal splines (43;243) and in engagement therewith is an insert member (79;279) which is, in turn, in splined engagement with a valve drive shaft (47;247). The insert member (79;279) extends axially beyond the star member and is received within an adjacent annular recess (85;285), thus maximizing the spline length available for engagement with the main drive shaft (39;239), and maximizing the torque capacity of the motor.

Abstract: A cushion valve arrangement for reducing the rate of pressure build up and relieving pressure rebounds in a fluid conduit. The valve housing defines first and second fluid ports, a fluid passage communicating therebetween, and a cushion passage communicating between the fluid passage and the first and second fluid ports. A valve spool is disposed in the fluid passage and defines an axial bore, within which is disposed a slideable valve member. When the pressure and flow suddenly builds up, the valve member is biased to an open position permitting high pressure fluid to pass through the axial bore and radially out through a passage in the spool into the cushion passage from which the fluid flows to the other conduit.

Abstract: Axial retention of the drive shaft is provided in a fluid pressure device of the type including an internally-toothed member, an externally-toothed member disposed eccentrically therein for relative orbital and rotational movement, and a drive shaft extending into a central bore defined by the externally-toothed member. The drive shaft has male splines and the externally-toothed member has female splines in the central bore, engaging the male splines. The front face of the externally-toothed member has a recess including a stop surface generally perpendicular to the axis of the device and the drive shaft has a shoulder extending radially outward and engaging the stop surface to limit the axial movement of the drive shaft into the central bore. Wear is minimized because the mating stop surface and shoulder are rotating at the same speed and, preferably, the shoulder "nutates" with respect to the stop surface.