| 摘要 |
PURPOSE:To prevent the generation of a surge pressure and elongate the life of the pump by a method wherein excess delivery oil of the pump, which is corresponding to the delay of the response of a variable mechanism which generates the surge pressure, is escaped into a tank through a surge absorbing valve arranged in relation with the pump. CONSTITUTION:When a valve is closed suddenly, for instance, the surge pressure is generated in the pump and the control pressure of the oil chamber 23 of a main piston 4 shows a similar peak pressure. When the surge pressure of the control pressure becomes larger than a preset pressure, the poppet 107 of the surge pressure absorbing valve A, arranged in relation with the pump, is moved to the right in the diagram and the delivery oil of the pump escapes to a tank port T. According to this operation, a pressure, exceeding the pump pressure corresponding to the preset pressure, may be removed in the surge pressure. As a result, when a spring 108 is set once, it is not necessary to effect the trouble some adjustments of it afterward, the surge pressure may be removed effectively and the life of the pump may be elongated. |
