| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a shovel on which a hydraulic circuit is mounted for allowing efficient operation of two hydraulic pumps and one pump motor.SOLUTION: The shovel includes an accumulator 80, a first pump 14L for discharging first working oil, a second pump 14R for discharging second working oil, a pump motor 14A for receiving working oil flowing out of a boom cylinder 7 to produce a back pressure in the boom cylinder 7 and to generate rotating torque, and a confluence valve 55 for selecting the joint of the first working oil and the second working oil or the cut-off of the joint. When the operation of the boom cylinder 7 with the deadweight of a boom is performed, the pump motor 14A produces the back pressure to control the operating speed of the boom cylinder 7 and to rotate the first pump 14L with the generated rotating torque, and the accumulator 80 receives the first working oil discharged by the first pump 14L.</p> |
