PUMP OF AN ELECTRONICALLY CONTROLLED BRAKE SYSTEM FOR IMPROVING OIL FILLING RATIO OF A PRESSURIZING CHAMBER BY SMOOTHING OPENING OF AN INLET VALVE WITHOUT RESTRICTION OF A RECIPROCATING MOTION OF A PISTON

摘要

PURPOSE: A pump of an electronically controlled brake system is provided to separate quickly a valve opening and closing member from a valve seat by preventing a motion of an inlet valve from being restricted by a reciprocating motion of a piston, accordingly to improve opening motion of an inlet valve, and to increase oil filling ratio of a pressurizing chamber. CONSTITUTION: A pump(15L,15R) of an electronically controlled brake system is composed of a bore(25) formed in a modulator block(18) to position a spindle of a motor(16) at one end and to communicate with suction and discharge ports(23,24); a piston(30) installed in the bore to reciprocate rectilinearly; a cover(50) combined to the other end of the bore to form a pressurizing chamber(40) between the cover and a tip of the piston; and a return spring(41) arranged in the pressurizing chamber to elastically support the piston toward the motor. The pressurizing chamber communicates with the discharge port. The discharge port has an outlet valve(70) for opening and closing the discharge port to send the oil of the pressurizing chamber to the discharge port. The cover has a suction passage(51) for transmitting the oil of the suction port to the pressurizing chamber. An inlet valve(60) is disposed at the pressurizing chamber of an outlet of the suction passage, operated oppositely to the outlet valve according to a reciprocating motion of the piston, and fixed on the cover to open and close the suction passage.