| 摘要 |
<p>PURPOSE:To save the energy of pump driving force by applying each delivery pressure of both variable delivery pumps and the effective differential pressure between the delivery pressure and control pressure opposedly to both sides of a confluence valve. CONSTITUTION:The sum of the delivery pressure PA of a variable delivery pump 10 and the differential pressure P of a control part 24, and the delivery pressure PB of a variable delivery pump 12 are applied to one side of a confluence valve 34 provided between the pressure oil delivery lines 18, 20 of both variable delivery pumps 10, 12. The sum of the delivery pressure PA of the variable delivery pump 10, the delivery pressure PB of the variable delivery pump 12 and the differential pressure P of a control part 26 is applied to the other side of the confluence valve 34. The delivery flow control lines 36, 38 of both variable delivery pumps 10, 12 are further connected through shuttle valves 40, 42 and the confluence valve 34. Accordingly, at the time of supplying the delivery pressure oil of the variable delivery pump on the high pressure load side into an actuator on the low pressure load side, the delivery pressure of the variable delivery pump on the low pressure load side is not needed to be boosted, and therefore the energy of pump driving force can be saved.</p> |
