| 摘要 |
PURPOSE:To eliminate a motive power loss and enable the operation of a pump with energy economization, by effecting control so that the discharge of the pump can optionally be made lower than a set quantity, in a prescribed range of relationship between the pressure and quantity of the discharge. CONSTITUTION:A control valve 20 functions to keep a pump in a prescribed relationshp between the pressure and quantity of discharge. An operating valve 40 functions so that the discharge quantity of the pump can be made lower than a set level, in a pump capacity control range set by the control valve 20. When desired external operating pressure is applied to the piston of the operating valve 40 to drive its operating spool, a communication passage 49 is connected to a tank passage 47 and the rear chamber 14a on a control plunger 14 for a swash plate is connected to the tank passage 47. As a result, the inclination angle of the swash plate is changed and maintained at a value corresponding to the external operating pressure. |
