Patent ID: 6293777
Filing Date: 2001-09-25
Classification: F04C,Y10T

Abstract:
A hydraulic positive displacement machine comprising:a housing (30, 52) having housing walls defining a housing interior (32);said housing walls having an intake opening (46) and an outlet opening (50);conveying elements (34, 36) mounted in said housing interior (32) and configured to convey a hydraulic medium from said intake opening (46) through said housing interior (32) to said outlet opening (50) and to expel the hydraulic medium under pressure from said outlet opening (50);said conveying elements (34, 36) having end faces;at least one pressure plate (42) acting on said end faces of said conveying elements (34, 36) to seal said conveying elements (34, 36);a control device (14, 16; 62) configured to control a pressure loading said at least one pressure plate (42) into a sealing position against said end faces of said conveying elements (34, 36);said control device (14, 16; 62) having a control valve (62);said control valve (62) having a valve housing (84) and a piston (88) reciprocatingly mounted in said valve housing (84);said control valve (62) having a pressure connector arrangement, comprised of an inlet connector (106) and an outlet connector (108);said piston (88) having a throughbore with a metering orifice bore (104) connecting said inlet connector (106) and said outlet connector (108) with one another;a spring (100) mounted in said valve housing (84) and resting against said piston (88) and an inner wall of said valve housing (84);wherein said piston (88) is loaded by a first pressure of the hydraulic medium upstream of said metering orifice bore (104) and a second pressure of said hydraulic medium downstream of said metering orifice bore (104) and is moreover biased by said spring (100);said valve housing (84) having a control connector (114) hydraulically connected to said at least one pressure plate (42) and a return connector (116) for the hydraulic medium;wherein, depending on a pressure differential (.DELTA.p) of said first and second pressures, said control connector (114) is configured to be connected via said piston (88) to said pressure connector arrangement (106, 108) for increasing pressure on said pressure plate (42) and to be connected to said return connector (116) for reducing the pressure on said pressure plate (42).