Patent ID: 8307752
Filing Date: 2012-11-13
Classification: F03C

Abstract:
1. A radial-piston hydraulic motor comprising: a fixed central shaft with a plurality of piston bodies with a plurality of pistons, one of said plurality of pistons mounted in each piston body for radial motion; a plurality of presser wheels, one of said plurality of presser wheels mounted on each piston; a casing surrounding the central shaft, and the casing mounted for rotation on the central shaft; a cam ring having a wave-shaped surface mounted to the casing so that the presser wheels mounted to the pistons bear on the cam ring wave-shaped surface; wherein the plurality of piston bodies are divided into a first group of piston bodies and a second group of piston bodies; first portions of the central shaft forming a first supply channel which is connected to the first group of piston bodies by a distributor mounted to rotate with the casing; second portions of the central shaft forming a second supply channel which is connected to the second group of piston bodies by the distributor; an actuator which is actuated by a pressure in the first supply channel to open and close the second supply channel with respect to the second group of piston bodies, the actuator connected to the first supply channel by a structure arranged to transmit a pressure medium from the first supply channel such that when pressure in the pressure medium in the first supply channel falls below a selected value the actuator closes the second supply channel with respect to the second group of piston bodies, so that only the first supply channel conducts the pressure medium at a working pressure to the first group of piston bodies and the second group of piston bodies are turned off and thus not operating at the working pressure.