| 摘要 |
PURPOSE:To omit a hydraulic cylinder, by employing such an arrangement that both of the confined sections on the suction side and on the discharge side are communicated with each other directly when the line pressure is lower than the set pressure of a regulator valve and a cam ring is moved to a most displaced position by a spring. CONSTITUTION:When the speed of rotation of a rotor 24 is low and the line pressure is lower than the set pressure of a regulator valve 31, oil passages 33 and 34 are communicated with each other by the regulator valve 31, so that the hydraulic pressure in a confined section 32 on the discharge side is introduced into a confined section 35 on the suction side. Resultantly, the hydraulic pressure in the section 32 and that in the section 35 become equal to each other, so that no force due to the hydraulic pressure is acted to a cam ring 21. Therefore, the cam ring 21 pushed to the most displaced position by the force of a spring 25 and the discharge volume is increased. By employing such an arrangement, it is enabled to omit a hydraulic cylinder that has been required for oscillating the cam ring 21 and to reduce the size of a control apparatus for a pump. |
