| 摘要 |
<p>PURPOSE:To enlarge an effective utilizing range of a prime mover output and to improve its efficiency, by connecting a unload valve in parallel to each auxiliary circuit and by opening the unload valve when the total pressure of a main circuits reaches a given value. CONSTITUTION:A prime mover 1 is connected to at least two constant-volume main pumps 2a, 2b and constant-volume auxiliary pumps 3a, 3b which correspond to the aforesaid main pumps. The system allows the pressured oil to individually join circuits 4a and 4b connected to the main pumps 2a and 2b respectively through auxiliary circuits 7a and 7b respectively. Unload valves 8a and 8b are connected in parallel to the circuits 7a and 7b. Pilot circuits 11a, 11b and 12a, 12b are placed at the valves 8a and 8b, and the circuits 11a and 12a are connected to a pilot circuit 13a connected to the circuit 4a, and the other circuits 11b and 12b connected to a pilot circuit 13b connected to the circuit 4b. And thus, when the total pressure of the circuits 4a and 4b is excess of a given value, the valves 8a and 8b are worked to discharge hydraulic oil to a tank 10.</p> |
