CONTROL DEVICE FOR VARIABLE VOLUME TYPE PUMP

• Main Authors: SAKAI RYUJI, MATSUDA NORIHIDE, KAWABATA SACHIO
• Format: Patent
• Language: English
• Published: 13.10.1998
• Edition: 6
• Subjects: BLASTING; HEATING; LIGHTING; MECHANICAL ENGINEERING; POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS; WEAPONS

PROBLEM TO BE SOLVED: To provide a control device for a variable volume pump to precisely control a relief amount from an electromagnetic relief valve during control of a pressure to a value lower than a specified value. SOLUTION: A control device for a variable volume type pump to change a delivery flow rate of working oil by changing a variable element comprises a first feedback circuit 24 to control a pressure of working oil from a variable volume type pump: a second feedback circuit 24a; and a switch control means 88. A first feedback circuit 24 comprises a first pressure detecting means to detect a working pressure; a second pressure detecting means to detect the vent pressure of an electromagnetic relief valve; and a differential pressure computing circuit 122 to compute a differential pressure between the detecting pressures of first and second pressure detecting means. The switch control means 88 performs switch control such that a relief flow rate of working oil is decreased by utilizing a differential signal from the differential pressure computing circuit 122 when the detecting pressure of the first pressure detecting means is higher than a target pressure.