Patent ID: 7445298
Filing Date: 2008-11-04
Classification: B60T

Abstract:
1. A brake control apparatus for a vehicle, comprising: a brake operating member operated by an operator of the vehicle; an operation amount sensor for detecting an operation amount of the brake operating member; first and second front wheel cylinders mounted at first and second front wheels of the vehicle respectively; first and second rear wheel cylinders mounted at first and second rear wheels of the vehicle respectively; a reservoir for storing brake fluid; a main conduit connecting the first and second front wheel cylinders and the first and second rear wheel cylinders with the reservoir, the main conduit branching into four conduits respectively connected with the first and second front wheel cylinders and the first and second rear wheel cylinders; a first pump located in the first one of the four conduits for supplying pressurized brake fluid to the first front wheel cylinder by suctioning and discharging the brake fluid stored in the reservoir; a second pump located in the second one of the four conduits for supplying pressurized brake fluid to the first rear wheel cylinder by suctioning and discharging the brake fluid stored in the reservoir; a third pump located in the third one of the four conduits for supplying pressurized brake fluid to the second front wheel cylinder by suctioning and discharging the brake fluid stored in the reservoir; a fourth pump located in the fourth one of the four conduits for supplying pressurized brake fluid to the second rear wheel cylinder by suctioning and discharging the brake fluid stored in the reservoir; a first conduit system arranged in the main conduit and including the first pump and the second pump for supplying the pressurized brake fluid to the first front wheel cylinder and the first rear wheel cylinder, respectively; a second conduit system arranged in the main conduit and including the third pump and the fourth pump for supplying the pressurized brake fluid to the second front wheel cylinder and the second rear wheel cylinder, respectively; a first motor provided at the first conduit system for driving the first and the second pumps; a second motor provided at the second conduit system for driving the third and the fourth pumps; first, second, third and fourth pressure modulating circuits arranged in parallel with the first, second, third and fourth pumps for returning the brake fluid in the wheel cylinders to the reservoir; first, second, third and fourth linear valves provided at the corresponding first, second, third and fourth pressure modulating circuits, respectively; controlling means driving the first, second, third and fourth linear valves and the first and the second motors based on a detection signal from the operating amount sensor, determining a brake operation starting time to a time when the brake operating member is detected to be operated based upon the operating amount sensor, controlling a value of electric current to be supplied to each first and second motor to the maximum value since the brake operation starting time, and changing the value of electric current to a value corresponding to a target wheel cylinder pressure of each wheel cylinder corresponding to an operation amount detected by the operation amount detecting sensor from the maximum value, and the controlling means including: