| 摘要 |
PURPOSE:To gently absorb inertia force of a vehicle at its stopping and prevent a shock of the stopping, by interposing a pair of relief valves between a hydraulic motor and a counterbalance valve in a hydraulic driving gear of the vehicle. CONSTITUTION:If a directional control valve is selected for power driving of a vehicle, a line 7A is connected to a hydraulic pump while a line 6A is connected to a tank, and a spool 16 is displaced to the right by a differential pressure, causing the rotation of a hydraulic motor 1. Pressures in spring chambers 23A, 23B close poppet valves 22A, 22B to lock relief valves 12A, 12B. If the directional control valve is placed in the neutral position at stopping of the vehicle, the lines 6A, 7A are connected to the tank, causing reduction in the pressure, and the spool 16 is returned to its neutral position, resulting in also reduction of the pressure in the spring chambers 23A, 23B. If inertia force acts on the hydraulic motor 1 to cause it to perform pumping action, high pressure is generated in a line 6B to act on the poppet valve 22A, and if the pressure exceeds a preset value of the relief valve 12A, the poppet valve 22A moves apart from its seat and the pressure is relieved to the side of a line 7B. |
