| 摘要 |
<p>PURPOSE:To remarkably improve working efficiency of hydraulic shovel by increasing its operating speed in such a way that three constant displacement pumps are coordinated in hydraulic circuit of hydraulic shovel, and pressure oil from third pump is fed into any actuator which should speed up. CONSTITUTION:Boom cylinder C1, bucket cylinder C2 and operating circuit for travelling hydraulic motor M1 are connected parallel to each other between first main circuit 21 connected to first pump P1 and return oil circuit 24 to tank 20 through respective main change-over valves 11, 12, and 13. Branch valve 31 is disposed in third main circuit 23 connected to third pump P3 so as to divide the third main circuit 23 into first and secound branch circuits 32 and 33. The first branch circuit 32, the second branch circuit 33, and second main circuit 22 connected to second pump P2 are connected through circuit change-over valve 34 to respective first, second, and thirs relay circuits 35, 36, and 37, so that any one of actuators including said cylinders C1, C2 and said travelling motor M1 can be fed with pressure oil from third pump P3 through any one of circuits combined as above.</p> |
