省エネルギー形電気・油圧サーボ系 定容量形油圧ポンプの回転数制御

A conventional valve-controlled servo system is usually powered by a constant pressure power source where the pressure is set by a relief valve. In this kind of power source, the power loss becomes maximum when the actuator is stopping at a certain position.In this study, a new type of energy-saving power source is proposed. In this power source, the speed of the induction motor to drive the fixed displacement pump is controlled by an inverter in order to adjust the delivery of this pump and to control the system pressure without making use of the relief valve. The power efficiency of the energy-saving power source with the inverter is investigated. The methods of pressure feedback control and programmed control using the microcomputer are discussed and the results have been experimentally verified.