Robert Bosch Technology Corporation

Richard Lee Harbaugh

A brake system (10) having a proportioning device (18) through which a first fluid pressure is communicated to a first brake circuit and a second fluid pressure is communicated to a second brake circuit. The proportioning device (18) has a housing (90) with a first bore (204) connected with a first passage (98) for receiving the first fluid pressure and with a second passage (100) for receiving the second fluid pressure. A first piston (210) located in the first bore (204) of the housing (90) separates the first passage (98) from the second passage (100). The first piston (210) responds to a higher fluid pressure of the first and second fluid pressures by moving in the first bore (204) to providing additional fluid pressure to a lower fluid pressure of the first and second fluid pressures to substantially equalize the first and second fluid pressures supplied to the first and second brakes circuits for effecting said brake application. A second piston (110) located in a second bore (104) of the housing (90) separates the first passage (98) from the second passage (100). The second piston (110) responds to a pressure differential between the first and second fluid pressures to interrupt communication to the first or second brake circuit correspondingly connected to the lower fluid pressure while opening communication (124,126) with a reservoir (96) for the lower fluid pressure to prevent loss of fluid from the brake system.

Proportioning device for a brake system

A brake assembly (10,210,310,410) with a master cylinder totally integrated into a brake assembly. A housing for the brake assembly has an interior separated by a movable wall (30,30') to define first (32,32') and second (34,34') chambers. End element (18) secured to the housing has projection (17) located in the first chamber (32,32') with a plurality of passages (98,100) for communicating fluid to a brake system. A cylindrical member (60, 260,360,460) has a blind bore (74) that extends from a first end (70,264,364) toward a second end (72,266,366). The cylindrical member (60,260,360,460) slidably and sealingly engages the end element (18) to connect the blind bore (74) with the plurality of passages (98,100). A reaction member (120) is located between the hub member (46) and the cylindrical member (60, 260,360,460). A resilient arrangement (80, 388,390,488,490) urges the cylindrical member (60,260,360,460) toward the reaction member (120) to define pressurizing chambers (84,86,284,286,384,386) in the blind bore (74). The actuation force acts through the reaction member (120) to initially move the cylindrical member (60,260,360,460) into engagement with the end element (18) to terminated communication with a source of compensation fluid and establish specific flow paths between the blind bore (74) and the plurality of passages (98,100) connected to the brake system. After overcoming the force of the resilient arrangement (80,388,390,488,490), the cylindrical member (60,260,360,460) continues to move and pressurizing fluid in chambers (84,86,284,286,384,386). This pressurized fluid is communicated through the specified flow paths to effect a brake application.

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South Bend, IN, United States of America

Richard Lee Harbaugh