JPS649057A - Anti-skid control device - Google Patents

Abstract

PURPOSE:To aim at miniaturizing an accumulator or a pump by providing a second valve device which opens and closes the discharge side of the pump in accordance with the differential pressure between the master cylinder side pressure and the pump pressurized pressure, for controlling a pressurized liquid passage led to a main pipe line, on the master cylinder side of a release circuit. CONSTITUTION:When hydraulic fluid is discharged from a wheel cylinder 4 into a hydraulic fluid reservoir 16, a pump 14 pressurizes the hydraulic fluid and transmits its discharge output to a control port 10. This pressure allows a third plunger 31 to descend until it abuts against a plate member 33, and simultaneously, a plunger 24 is moved upward. When the pressure is increased, the plunger 24 is at first moved overcoming the pressure of a master cylinder 2 until a ball valve 26 is seated on a valve seat 26. When the pressure is further increased, a ball 28 is lifted up from a valve seat 30 so as to increase the pressure between a selector valve 12 and the ball valve 25. Thereafter, when the discharge pressure of the pump 14 approaches the clacking pressure of a relief valve 17, a rubber spring 34 is also compressed so as to open the valve 17, and the discharge side pressure of the pump 14 becomes constant after it is increased to the clacking pressure of the relief valve.