초록 ▼

The invention is directed to a hydraulic braking system having a master cylinder (10) in which a first piston and a second piston are slidably disposed to define a first pressure chamber (11) and a second pressure chamber (12). A valve device (24) is provided between the first pressure chamber and a

The invention is directed to a hydraulic braking system having a master cylinder (10) in which a first piston and a second piston are slidably disposed to define a first pressure chamber (11) and a second pressure chamber (12). A valve device (24) is provided between the first pressure chamber and a reservoir (20). A first pressure control device (30, 31) is provided between the first pressure chamber and wheel cylinders (38, 39), and a second pressure control device (32, 33) is provided between the second pressure chamber and wheel cylinders (40, 41). A pump (27) is provided in a passage connecting the reservoir and the first pressure control device, and driven to supply a brake pressure from the former to the latter. When the valve device is actuated to block the communication between the first pressure chamber and the reservoir, and the pump is driven, the pressure in the first pressure chamber will be increased to move the second piston, so that the pressure in the second pressure chamber will be increased. Accordingly, the pressure in each wheel cylinder may be controlled by the first or second pressure control device without depressing the brake pedal.

대표청구항 ▼

A hydraulic braking system for an automotive vehicle, comprising; a master cylinder having a housing defining therein a bore, a first piston slidably disposed in said bore and moved in response to depression of a brake pedal, a second piston slidably disposed in said bore at the side of said first p

A hydraulic braking system for an automotive vehicle, comprising; a master cylinder having a housing defining therein a bore, a first piston slidably disposed in said bore and moved in response to depression of a brake pedal, a second piston slidably disposed in said bore at the side of said first piston opposite to said brake pedal, said first piston and said second piston defining therebetween a first pressure chamber communicating with a first port and a second port formed on said housing, said second piston defining at the side thereof opposite to said first chamber a second chamber communicating with a third port and a fourth port formed on said housing, said first piston blocking the communication between said first port and said first pressure chamber, and said second piston blocking the communication between said third port and said second pressure chamber, respectively, with said brake pedal depressed; a reservoir for storing an amount of brake fluid, said reservoir communicating with said third port of said master cylinder; first valve means for opening or closing the communication between said first port of said master cylinder and said reservoir; pump means having an input port communicating with said reservoir, and an output port communicating with said second port of said master cylinder, said pump means sucking the brake fluid from said reservoir and discharging the pumped brake fluid to said second port; a plurality of wheel cylinders operatively mounted on respective wheels for braking said wheels, said wheel cylinders being divided into a first group of wheel cylinders and a second group of wheel cylinders; first pressure control means provided between said second port of said master cylinder and said first group of wheel cylinders for controlling the pressure in said second port; second pressure control means provided between said fourth port of said master cylinder and said second group of wheel cylinders for controlling the pressure in said fourth port; and valve control means for actuating said first valve means to open or close the communication between said first port of said master cylinder and said reservoir in accordance with a mode selected from an opening mode and a closing mode.