| 摘要 |
A vehicle antilock braking system having an operator controlled master cylinder (11, 11a) and a second source of pressurized hydraulic fluid (35) for selectively supplying rebuild pressure after an antilock event to simultaneously actuate each wheel braking device, and a solenoid actuated two position flow control valve (10, 10a, 25, 45) for each wheel in circuit between the source (11, 11a, 35) and the associated wheel braking device for selectively directing fluid from the source (11, 11a, 35) to the braking device to brake the vehicle, and from the braking device to relieve braking force has an improved hydraulic pressure actuated dual inlet, single outlet two position valve (21, 23, 49, 49a) for each of the wheels which is effective in a first position to pass hydraulic fluid from the operator controlled source (11, 11a) to the corresponding flow control valve (10, 10a, 25, 45) for selectively actuating the corresponding braking device, and in a second position to block the passage of hydraulic fluid from the operator controlled source to the corresponding flow control valve (10, 10a, 25, 45) and to provide instead a hydraulic fluid path from the second source (35) to the corresponding flow control valve (10, 10a, 25, 45). A bypass pressure regulator (43) responsive to master cylinder (11, 11a) and rebuild pressures to supply pressurized hydraulic fluid from the second source (35) to each of the pressure actuated valves (21, 23, 49, 49a) only when the operator controlled master cylinder (11, 11a) is supplying pressurized hydraulic fluid. The pressure of the hydraulic fluid supplied from the second source (35) to each of the pressure actuated valves (21, 23, 49, 49a) is directly proportional to the pressure of the operator controlled master cylinder (11, 11a) pressure. The master cylinder (11, 11a) has n chambers each selectively supplying pressurized hydraulic fluid to n corresponding control ports (63, 65, 67). The regulator (43) responds to these jointly, but non-additively to continue to function and supply rebuild pressure despite failure of any n-1 of the master cylinder chambers (11, 11a).
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