VARIABLE DISPLACEMENT VANE PUMP DEVICE

摘要

PURPOSE:To prevent a driver from being given an uncomfortable feeling of steering due to switching action of a switching valve. CONSTITUTION:A solenoid valve 16 serving as a mechanism for controlling switching is provided in a switching valve 1 for performing communication and interruption between a specific suction port 41' and a specific delivery port 31', to control this solenoid valve 16 so that operating oil is circulated by a specific pump chamber to obtain 1-port delivery only in the case of large car speed and small steering wheel angle, and a sudden change of assist force caused by switching the switching valve at low speed time can be eliminated by accurate control. Operation of the solenoid valve 16 is controlled by a car speed and an engine speed, so as to obtain 1-port delivery by circulating the operating oil in the specific pump chamber only when the car speed and the engine speed are both larger than a preset value, and assist force is prevented from suddenly changing due to switching generated when only the car speed or engine speed is changed.