PURPOSE: To prevent wasteful power consumption by connecting or disconnecting a discharge pressure adjustable discharge means and a discharge means controlled to the stationary pressure, and feeding the combined discharge fluids of them or either one of the discharge fluids in a fluid pressure device such as a molding machine.
CONSTITUTION: The pump main body 10 of the first variable-displacement pump 1 and the pump main body 20 of the second variable-displacement pump 2 are driven by a single motor 9, and they are controlled by pressure sensors p1-p3 and a computer 40. Two kinds of high and low discharge pressures are fed to a fluid actuator 3 via compensator valves 12, 22, high-pressure setting relief valves 13, 25, and low-pressure setting relief valves 14, 26. The right and left functions of the compensator valves 12, 22 are switched in response to the discharge pressures of the pump main bodies 10, 20, and the combined discharge fluids of set pressures or only either one of them is fed to the fluid actuator 3.
HIRANO KENICHI
KAMATA NAGAAKI
YUKEN KOGYO CO LTD