US 9,481,349 B2 · Vehicle brake device

Abstract

A brake ECU uses a control pressure acquired from a control pressure sensor to determine whether a valve closing operation abnormality or a valve opening operation abnormality occurs in one of a pressure increasing linear control valve and an adjusted flow rate cut valve in a state where a hydraulic pressure is supplied from an accumulator. The brake ECU controls, if the brake ECU determines that an abnormality occurs, respectively the control valve and the cut valve to change to an open state or a closed state, and identifies, based on a change in the control pressure acquired from the control pressure sensor, in which of the control valve and the cut valve the valve opening operation abnormality or the valve closing operation abnormality occurs. The brake ECU can use, after a valve in which the valve opening operation abnormality or the valve closing operation abnormality occurs is identified, a valve in which the abnormality does not occur to carry out brake control.

A vehicle brake device, comprising:

a wheel cylinder for receiving a hydraulic pressure of a working fluid and applying a braking force to a wheel;
a master cylinder for introducing therein a servo pressure generated in response to an operation by a driver on a brake pedal, thereby generating a hydraulic pressure;
a power hydraulic pressure source for generating a hydraulic pressure by drive of a pressurizing pump;
a pressure adjustment control valve for adjusting the hydraulic pressure transmitted from the power hydraulic pressure source to the wheel cylinder;
first hydraulic pressure detection means for detecting the hydraulic pressure output from the power hydraulic pressure source;
second hydraulic pressure detection means for detecting the hydraulic pressure output from the master cylinder;
third hydraulic pressure detection means for detecting the hydraulic pressure output via the pressure adjustment control valve and transmitted to the wheel cylinder;
and
a control unit for controlling drive of the power hydraulic pressure source and drive of the pressure adjustment control valve based on the hydraulic pressure output from the master cylinder and detected by the second hydraulic pressure detection means, and the hydraulic pressure transmitted to the wheel cylinder and detected by the third hydraulic pressure detection means, wherein:
the pressure adjustment control valve comprises:
a pressure increasing linear control valve used for pressure increasing control of increasing the hydraulic pressure transmitted from the power hydraulic pressure source to the wheel cylinder;
an electromagnetic on-off valve arranged in parallel to the pressure increasing linear control valve;
and a pressure decreasing linear control valve used for pressure decreasing control of decreasing the hydraulic pressure transmitted from the power hydraulic pressure source to the wheel cylinder;
and
the control unit is programmed to:
use, when a magnitude of the hydraulic pressure detected by the first hydraulic pressure detection means is a predetermined magnitude, a magnitude of the hydraulic pressure detected by the third hydraulic pressure detection means to determine whether or not an operation abnormality occurs in one of the pressure increasing linear control valve and the electromagnetic on-off valve that construct the pressure adjustment control valve;
control, when the control unit determines that the operation abnormality occurs in one of the pressure increasing linear control valve and the electromagnetic on-off valve, each of the pressure increasing linear control valve and the electromagnetic on-off valve to change from a closed state to an open state or from the open state to the closed state;
and
identify, based on a change in the hydraulic pressure generated in response to the change control and detected by the third hydraulic pressure detection means, in which of the pressure increasing linear control valve and the electromagnetic on-off valve the operation abnormality occurs,
wherein the control unit is programmed to:
determine, in a case where the control unit controls the pressure increasing linear control valve and the electromagnetic on-off valve to the closed state when the magnitude of the hydraulic pressure detected by the first hydraulic pressure detection means is the predetermined magnitude, and the magnitude of the hydraulic pressure detected by the third hydraulic pressure detection means increases, that a valve closing operation abnormality occurs in which the open state is maintained even when the change control of bringing one of the pressure increasing linear control valve and the electromagnetic on-off valve from the open state into the closed state is carried out;
and
determine, in a case where the control unit controls the pressure increasing linear control valve and the electromagnetic on-off valve to the open state when the magnitude of the hydraulic pressure detected by the first hydraulic pressure detection means is the predetermined magnitude, and the magnitude of the hydraulic pressure detected by the third hydraulic pressure detection means is less than a magnitude of a target hydraulic pressure, that a valve opening operation abnormality occurs in which the closed state is maintained even when the change control of bringing one of the pressure increasing linear control valve and the electromagnetic on-off valve from the closed state into the open state is carried out,
and wherein the control unit is further programmed to, when the control unit determines that the valve closing operation abnormality occurs in one of the pressure increasing linear control valve and the electromagnetic on-off valve:
control the pressure increasing linear control valve from the closed state to the open state, and control the electromagnetic on-off valve to the closed state;
identify, in a case where the magnitude of the hydraulic pressure detected by the third hydraulic pressure detection means is a magnitude of the hydraulic pressure transmitted from the power hydraulic pressure source to the wheel cylinder when only the pressure increasing linear control valve is controlled to the open state, that the valve closing operation abnormality occurs in the pressure increasing linear control valve;
and
identify, in a case where the magnitude of the hydraulic pressure detected by the third hydraulic pressure detection means is larger than the magnitude of the hydraulic pressure transmitted from the power hydraulic pressure source to the wheel cylinder when only the pressure increasing linear control valve is contra lied to the open state, that the valve closing operation abnormality occurs in the electromagnetic on-off valve.

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Vehicle brake device

Life of this patent

Vehicle brake device

Life of this patent

Abstract

Claims4