Patent ID: 6402263
Filing Date: 2002-06-11
Classification: B60T

Abstract:
A master cylinder (12) for use in a brake system (10) having a housing (22) with a first (42) and second (44) pistons located in a bore (20) by first (46) and second (48) resilient members to define first (50) and second (52) chambers therein, said first (50) and second (52) chambers respectively being connected to a reservoir (32) to receive fluid and maintain a desired fluid level in said brake system (10) and to front (24) and rear (26) wheel brakes to supply pressurized fluid to effect a brake application, said fluid received from said reservoir (32) by said second chamber (52) being controlled by a center port compensation valve (148) having a head (126â€²) connected to a linkage arrangement (124â€²) that joins a first retainer (94â€²) with a second retainer (96â€²) to cage said second resilient member (48), actuation means having a first input member (14) which responds to an operator input to initially move said first (42) and second (44) pistons to compress said second (48) resilient members and allow said head (126â€²) to engage a seat (40â€²) to terminate communication from said reservoir (32) to said second (52) chamber and thereafter pressurize fluid in said second (52) chamber to effect a first brake application, said actuation means being characterized by a second input member (200) that responds to an electronic signal to move a plunger (202) to compress said second resilient means (48) and bring said seat (40â€²) into engagement with said head (126â€²) to terminate communication from said reservoir (32) to said second chamber (52) and thereafter move said plunger into said second chamber (52) to pressurize fluid therein and effect a second brake application.