| 摘要 |
PURPOSE:To enable the combined operation of running, bucket operation, and the like to be performed and enhance cost performance, by recovering energy with a rotating or accelerating variable capacity hydraulic pump motor, at the time of horizontal extruding work. CONSTITUTION:When horizontal extrusion command is generated, then the head chamber of a boom hydraulic cylinder 6 is connected to a variable capacity hydraulic pump motor 31 via a change-over valve 35, and by high tension oil generated by lowering a boom, the variable capacity hydraulic pump motor 31 is rotated and functions as a motor, and torque is transmitted in the direction of accelerating a prime mover, and energy is recovered. In this case, by a boom hydraulic pump, a bucket hydraulic cylinder 8 and a running hydraulic motor are driven. Except the time of the horizontal extrusion command, by the change- over valve 35, the variable capacity hydraulic pump motor 31 is connected to the load side like a rotary motor for example and functions as a hydraulic pump. |
