Hydraulic control unit for a vehicular brake system having a self-priming pump

摘要

A hydraulic control unit of a vehicular brake system includes a housing having a cavity. Drive means is received in the cavity of the housing. A fluid supply source is in fluid communication with the housing. A piston slidably is disposed in the housing. The piston includes a first end and a second end wherein the second end is in contact with the drive means so that the piston moves from a bottom-dead-center position to a top-dead-center position. Biasing means is in contact with the first end of the piston so that the piston moves from a top-dead-center position to the bottom-dead-center position. A first variable-volume chamber is defined by the piston and the housing whereby fluid is transferred from the first variable-volume chamber when the piston moves from the bottom-dead-center position. A constant-volume chamber is defined by the piston and the housing, whereby fluid is transferred from the fluid supply source to the first variable-volume chamber when the piston moves from the top-dead-center position to the bottom-dead-center position. A second variable volume chamber is defined by the piston and the housing, whereby fluid is transferred from the fluid supply source to the second variable-volume chamber when the piston moves from the bottom-dead-center position to the top-dead-center position.