| 摘要 |
PURPOSE:To enable execution of various types of control responding to a load condition by a method wherein two back pressure chambers are partitioned on the back side of a servo piston to control the variable control element of a swash plate, a control passage is connected to the one thereof and a pilot passage to the other. CONSTITUTION:A sash plate type variable capacity type pump 10 is provided with a servo piston 2 to regulate the inclination angle of a swash plate, not shown, from a maximum inclination position (m) to a neutral position (n). The swash plate is pressed by a bias mechanism 3 containing a piston 31 energized by means of a delivery pressure introduced through a communicating passage 80. Further, a constant horse power control valve 4 is provided for introducing a control pressure to the back side of the servo piston 2. In this case, first and second back pressure chambers 21 and 22 partitioned by an auxiliary servo piston 5 are formed on the back side of the servo piston 2. The first back pressure chamber 21 is connected to a control passage 40 extended from the constant horse power control valve 4, and the second back pressure chamber 22 is connected to a pilot passage 6 running to an external pilot pressure source. |
