US 2011/0215638 A1 · BRAKE SYSTEM

Abstract

Provided is a brake system capable of preventing fuel efficiency of a vehicle from being lowered. After an operation of a brake pedal (60) is released, a pump (219, 319) is driven under a state in which opening/closure of valves included in an ABS/VDC actuator (8) are regulated so that pressure-reduction control for returning a brake fluid in wheel cylinders (7) to a master cylinder (2) is performed. Therefore, the brake fluid remaining in the wheel cylinders (7) is returned to the master cylinder (2) via the pump (219, 319) to increase a hydraulic pressure of the master cylinder (2). As a result, return characteristics of an electric actuation unit (3) are improved. Therefore, for example, even if viscosity of grease applied onto a rotary-to-linear motion converting mechanism (23) is increased at a low temperature or the like, pistons of the master cylinder (2) can be appropriately returned to initial positions. As a result, a drag state of brake pads can be prevented from being brought about, which can in turn improve fuel efficiency of the vehicle.

Claims20

Dependent claims

A brake system, comprising:

a master cylinder for generating a brake fluid pressure by movement of a piston;
a booster for actuating the piston of the master cylinder;
a hydraulic pressure control mechanism provided between the master cylinder and wheel cylinders, the hydraulic pressure control mechanism including a pump, for performing pressure-intensification control and pressure-reduction control of the brake fluid pressure for the wheel cylinders;
and
control means for controlling the hydraulic pressure control mechanism, the control means performing the pressure-reduction control for returning a brake fluid in the wheel cylinders to the master cylinder by driving the pump of the hydraulic pressure control mechanism after the actuation of the piston by the booster is released.

2 more elements

A brake system, comprising:

a master cylinder for generating a brake fluid pressure by movement of a piston;
a booster for actuating the piston of the master cylinder by rotation of an electric motor;
a hydraulic pressure control mechanism provided between the master cylinder and wheel cylinders, the hydraulic pressure control mechanism including a pump, for performing pressure intensification and pressure reduction of the brake fluid pressure for the wheel cylinders;
hydraulic pressure detection means provided between the master cylinder and the wheel cylinders, for detecting the brake fluid pressure;
and
control means connected to the hydraulic pressure detection means and a control circuit of the electric motor of the booster, for controlling the hydraulic pressure control mechanism,
wherein, after the actuation of the piston by the booster is released, if the hydraulic pressure detection means detects that a hydraulic pressure is equal to or higher than a predetermined hydraulic pressure and/or if a rotational position of a rotor of the electric motor of the booster does not reach a predetermined position, the control means performs the pressure reduction control for returning a brake fluid in the wheel cylinders to the master cylinder by driving the pump of the hydraulic pressure control mechanism.

4 more elements

Dependencies are inferred from the claim text.

Brake system

Life of this patent

Brake system

Life of this patent

Abstract

Claims20