| 摘要 |
PURPOSE:To enable a pump swash plate angle to be precisely controlled by allowing pump discharge pressure and control pressure to be applied to the input signal part of a hydraulic servo as piston position displacement. CONSTITUTION:When an arm 37 is displaced clockwise taking a pin 39 as a fulcrum, a spool 38 is again returned in the direction toward the original position, and a servo piston 30 is displaced until said spool 38 returns to the original position to permit a port 72-b to be again blocked. Then, a left side chamber 74 is communicated with a case drain 94 through a passage 73, a port 72-a, and the passage 38-a of the spool 38. Namely, the servo piston 30 is displaced in response to reducing valve output pressure, and a pump is inclined from a minimum swash plate angle position to a position corresponding to the reducing valve output pressure. When said reducing valve output pressure further rises, the left end of a spring seat 43 touches the right end of a spring seat 42 to permit a spring 40 to begin to bend, and at that time a relation between the reducing valve output pressure and the pump swash plate angle is determined in terms of the spring constant. |
