| 摘要 |
1,227,888. Fluid pressure control of brakes. GENERAL MOTORS CORP. 13 Nov., 1969 [3 Dec., 1968], No. 55615/69. Heading F2F. An hydraulic dual line brakes system for a motor-vehicle which includes a brake line pressure regulator 32 for regulating the pressure of hydraulic fluid applied to the rear wheel brakes during a brake application also includes a bypass device arranged in the system to by-pass the regulator 32, when there is a failure in the line not connected to the regulator, to permit operation of the rear brakes without regulation of line pressure. The by-pass device comprises a cylinder 62 housing dual pistons 61, 64 coupled together to define an annular chamber 63 between them and chambers 65, 65<SP>1</SP>, respectively. The regulator supply line 48 communicates with chamber 65<SP>1</SP> through a bore 69 and the front wheel brake line 46 communicates with chamber 65 through a bore 68, the regulator 32 being connected with the interior of cylinder 62 through a line 60 and bore 71 and an output line 59 to the rear brakes communicates with the interior of cylinder 62 through a bore 70. Compression springs 72 located in chambers 65, 65<SP>1</SP> serve to centre the pistons and during normal braking substantially equal pressures generated in master cylinder chambers 18, 18<SP>1</SP> are transmitted to chambers 65, 65<SP>1</SP> to maintain the mid position and connect the rear brakes to pressure via the regulator. Failure of pressure in the front wheel brake circuit however moves the pistons to cover bore 71 and allow fluid pressure to be transmitted from line 48 via bore 69 and bore 70 direct to the rear brakes. Failure of either circuit causes pistons 61, 64 to be moved to operate a contact 80 and energize a warning light. |
