| 摘要 |
A hydraulic system has a cylinder and ram assembly (68) that raises and lowers a load carrying carriage (32) on a material handling vehicle (10). The fluid exhausting from the cylinder, while the carriage is lowering, is controlled to recover energy from that fluid. A first path (73) routes the exhausting fluid to drive the pump (64) as a hydraulic motor. A second path (85) routes the exhausting fluid to a reservoir (66), bypassing the pump. In a first lowering mode, the second path is closed and the first path is opened. In a second lowering mode, both the first and second paths are open and the flow through each one is proportionally controlled. In a third lowering mode, only the second path is opened. The mode to use is selected based on the desired lowering speed of the carriage. |
