| 摘要 |
The device has at least one hydraulic lifting cylinder (20) and a hydraulic pump (12) that supplies the cylinder in a lifting process and acts as a motor in a lowering process. An electric machine (10) acts as an electric motor in the lifting process and as a generator in the lowering process. A control device controls the rpm of the electric machine by controlling a valve arrangement. The rpm of the electric machine is controlled by a device that is supplied by the hydraulic pump to control a lowering branch (26) between the valve arrangement and a connection between a check valve and the pump input and at least one additional hydraulic consumer over the valve arrangement. The electric machine is controlled according to the valve arrangement operation. A hydraulic volume flow limiter is arranged in the lowering branch, to lower the overall hydraulic pressure at determined operation points and hold the load. A volume flow distributor is arranged in the lowering branch, which distributes the volume flow from the lifting cylinder to a tank (14) and the pump input. The flow to the pump is determined by the rpm control device of the electric machine. A controllable bypass valve (38) between the pump output and the tank to produce the lowering operation and supply an additional consumer (32). The additional consumer is cut off during the lifting process. |
