Conventionally, as proposed in Patent Document 1, there has been known a vehicle brake control device including linear control valves (composed of a pressure-increasing linear control valve and a pressure-decreasing linear control valve), each of which is provided on an individual passage for operating fluid from a power hydraulic pressure generating device to each wheel cylinder, the brake control device independently controlling a hydraulic pressure of a wheel cylinder for each wheel according to an energization control of the linear control valves.
The brake control device proposed in Patent Document 1 includes a pedal effort brake system in which the wheel cylinders for the front-left and front-right wheels are respectively connected to a master cylinder via two master passages to independently supply a hydraulic pressure, which is generated by a depressing operation on a brake pedal, to the wheel cylinders for the front-left and front-right wheels. A master cutoff valve that is a normally opened solenoid valve is provided to each of two master passages. During a hydraulic control, two master cutoff valves are kept closed, and after the hydraulic control is ended, energization of these master cutoff valves is stopped, so that they are kept opened. Accordingly, this brake control device is configured to be capable of generating braking force on the front-left and front-right wheels with the pedal effort brake system by using pedal effort on the brake pedal inputted by a driver, even if abnormality occurs on an electric system.
Patent Document 1 also proposes a brake control device including a front-wheel left-right communication passage that allows communication between wheel cylinders for front-left and front-right wheels and a rear-wheel left-right communication passage that allows communication between wheel cylinders for rear-left and rear-right wheels, wherein the front-wheel left-right communication passage and the rear-wheel left-right communication passage are provided with a normally opened solenoid on-off valve. In this brake control device, when abnormality occurs on an electric system, energization of the normally opened solenoid on-off valves on two communication passages is stopped, whereby the wheel cylinders for the front-left and front-right wheels are communicated with each other, and the wheel cylinders for the rear-left and rear-right wheels are communicated with each other.
USPTO Backgrounds
USPTO Backgrounds