CONTROL DEVICE OF VARIABLE CAPACITY PUMP

• Main Author: KAWABATA SACHIO
• Format: Patent
• Language: English
• Published: 18.05.1992
• Subjects: BLASTING; HEATING; LIGHTING; MECHANICAL ENGINEERING; POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS; WEAPONS

PURPOSE:To lessen the number of components used and simplify the configuration by conducting a pressure control and flow control through a set of solenoid- operated proportional decompression control valve and differential pressure type spool valve. CONSTITUTION:A controller 70 comprises No.1 adder/subtractor 71, which receives a pressure setting signal and a sensed pressure signal from pressure sensor 50 and emits their deviation epsilonP as output, and No.2 adder/subtractor 72 which receives a rate-of-flow setting signal and a sensed tilt angle signal from tilt angle sensor 60 and emits their deviation epsilonQ as output, and the controller emits selectively that epsilon of the deviations in which the tilt angle lessens. If epsilonP>epsilonQ after an oil-hydraulic pump 1 is started, the flow control is executed in priority, and a decompression control valve 20 is changed over to the supply position to cause decrease of the differential pressure P, so that a spool valve 10 is changed over to the exhaust side to cause increase of the tilt angle, and thus the rate of discharge flow will increase. When thereafter the discharge pressure Pd increases to generate the condition epsilonP<epsilonQ, the deviation epsilonP is selected, and the pressure control is executed so that the discharge pressure becomes the set pressure value.