| 摘要 |
PURPOSE:To aim at reducing energy loss, by carrying out the control of discharge flow of a pump with the use of the eccentric control of a cam ring, and further by controlling the discharge flow of the pump in such a way that the eccentricity of the cam ring is minimized when the pressure of the pump reaches its predetermined relief pressure. CONSTITUTION:When the rotational speed of a rotor 23 is increased so that the discharge flow of pressure medium to a first operating chamber r1 is increased, a cam ring 21 is swung to the left in the drawing, overcoming a spring 25, due to pressure differential between the first operating chamber r1 and a second operating chamber r2. As a result, the eccentricity of the cam ring 21 with respect to the rotor 23 is decreased in accordance with the increased pressure differential DELTAP (increase in rotational speed of a pump) so that the discharge volume per one revolution of the pump 1 is decreased, and therefore, the supply volume of pressure medium is controlled to be held constant irrespective of increase in the rotational speed of the pump. Then, when the medium pressure in the first operating chamber r1 reaches a relief pressure, a relief valve 37 is opened so that the pressure medium displaces a gap adjusting member 28 to the outer peripheral surface of the cam ring 21 for decreasing the eccentricity of the cam ring 21, thereby the pressure rise above the relief pressure is limited. |
