| 摘要 |
PURPOSE: To solve occurrence of working fluid bubbles and the continuous high load condition of a pump which make trouble when a relief valve is used in a pump controller by which pump discharge pressure is prevented from being exceeded over set upper limit pressure, by enabling the pump discharge pressure to be controlled without any relief valve. CONSTITUTION: In a brake system which makes a pump 76 to serve as a pressure source and operates a brake so as to execute traction control, a pilot type opening/closing valve 190 is provided between the pump 76 and a reservoir 70, and the opening/closing valve 190 is formed to be closed when the discharge pressure of the pump 76 reaches set upper limit pressure although the opening/ closing valve 190 is usually opened, so that a brake fluid flow led to flow from the reservoir 70 to the pump 76 is prevented. When brake fluid suction is prevented, the pump 76 comes in an ineffective condition and idles only, so that the increment of the discharge pressure and wastful consumption of driving energy can be avoided. |
