Variable displacement hydraulic rotary machine and system for controlling its operation

PURPOSE: To miniaturize and package a system by converting the displacement of a piston in a cylinder into the rotation of a shaft, and electronically controlling a valve means which selectively connects fluid inlet and outlet ports to a cylinder cavity. CONSTITUTION: The valve controllers 32 of electronic hydraulic devices 22a-22n perfrom closed-loop control of respective actuators 24 via servo valves 26 in response to control signals from a master controller 34. A variable displacement hydraulic pump system 40 performs closed-loop control of the output capacity of a pump 46 via a pump controller 42, a pump valve 44, and a yoke actuator 48 by feeding back the signals of a yoke position sensor 50, an output pressure sensor 52, and a rotation sensor 54. The controllers 42, 32 comprise microcomputers, and the controller 42 is mounted on the valve block of the pump valve 44 and covered. Thus, the variable displacement hydraulic pump system 40 can be miniaturized and compacted. COPYRIGHT: (C)1991,JPO