초록 ▼

A vehicle motion control apparatus includes hydraulic pressure applying means for applying hydraulic pressure to a wheel cylinder side of any of plural solenoid valves, respectively arranged between a master cylinder and plural wheel cylinders, for the corresponding wheel cylinders even when an oper

A vehicle motion control apparatus includes hydraulic pressure applying means for applying hydraulic pressure to a wheel cylinder side of any of plural solenoid valves, respectively arranged between a master cylinder and plural wheel cylinders, for the corresponding wheel cylinders even when an operator of the vehicle does not operate a brake operation member, motor controlling means for controlling an output of the electric motor to be reduced in accordance with a condition of a road surface when the hydraulic pressure is applied to the wheel cylinder, and valve controlling means for controlling the operation of the solenoid valve to increase an amount of the brake fluid flown by the operation of the solenoid valve before the output of the electric motor is reduced when the output of the electric motor is controlled to be reduced.

대표청구항 ▼

1. A vehicle motion control apparatus provided at a brake system including a master cylinder, wheel cylinders respectively provided at plural wheels of a vehicle, solenoid valves respectively provided between the master cylinder and the corresponding wheel cylinders and an electric motor operating a

1. A vehicle motion control apparatus provided at a brake system including a master cylinder, wheel cylinders respectively provided at plural wheels of a vehicle, solenoid valves respectively provided between the master cylinder and the corresponding wheel cylinders and an electric motor operating a pump for controlling a supply of brake fluid to the wheel cylinder, the vehicle motion control apparatus applying a hydraulic pressure to the wheel cylinders at a predetermined pressure increasing rate based on a condition of the vehicle regardless of operation of a brake operation member by an operator of the vehicle, the vehicle motion control apparatus comprising: hydraulic pressure applying means for applying the hydraulic pressure to any one of the wheel cylinders by operating the pump with the electric motor to supply brake fluid to a master cylinder side of the solenoid valve for the corresponding wheel cylinder and by controlling an operation of the solenoid valve to allow brake fluid to flow from the solenoid valve to a wheel cylinder side of the solenoid valve so that a target pressure increasing rate specified on a basis of the condition of the vehicle is satisfied even when the operator of the vehicle does not operate the brake operation member;motor controlling means for controlling an output of the electric motor to be reduced in accordance with a condition of a road surface, on which the vehicle drives, when the hydraulic pressure applying means applies the hydraulic pressure to the wheel cylinder;means for determining that the output of the electric motor has been reduced by the motor controlling means; andvalve controlling means for controlling the operation of the solenoid valve to increase an amount of brake fluid allowed to flow from the solenoid valve by the operation of the solenoid valve whenever the means for determining determines that of the output of the electric motor has been reduced to maintain the target pressure increasing rate when the motor controlling means controls the electric motor to reduce the output,wherein when the motion control apparatus applies a hydraulic pressure to the wheel cylinders at the predetermined pressure increase rate when the operator of the vehicle does not operate the brake operation member, a reduction of the pressure increasing rate relative to the wheel cylinders caused by a reduction of the output of the electric motor by the motor controlling means is compensated with an increase of the pressure increasing rate by controlling the solenoid valve by the valve controlling means to increase the amount of brake fluid allowed to flow to the wheel cylinders. 2. A vehicle motion control apparatus according to claim 1, wherein the output of the electric motor corresponds to rotational speed of the electric motor and the motor controlling means controls the rotational speed of the electric motor to be reduced, and wherein the valve controlling means controls the amount of brake fluid allowed to flow from the solenoid valve to be increased in accordance with a reduction degree of the rotational speed of the electric motor reduced by the motor controlling means. 3. A vehicle motion control apparatus according to claim 2, wherein the hydraulic pressure applying means controls the rotational speed of the electric motor and the amount of brake fluid allowed to flow from the solenoid valve so as to maintain a target pressure increasing rate determined on the basis of a condition of the vehicle and sets the amount of brake fluid on the basis of a pressure increasing rate and a characteristic predetermined for every rotational speed of the electric motor by the amount of brake fluid and the pressure increasing rate,and wherein the motor controlling means and the valve controlling means change a first rotational speed of the electric motor to a second rotational speed of the electric motor which is lower than the first rotational speed and change a first amount of brake fluid to a second amount of brake fluid which is greater than the first amount of brake fluid so that the second rotational speed and the second amount of brake fluid correspond to the target pressure increasing rate, the first rotational speed and the first amount of brake fluid is set to be the target pressure increasing rate, and the second amount of brake fluid is set on the basis of the target pressure increasing rate and the characteristic predefined by the amount of brake fluid and the pressure increasing rate relative to the second rotational speed of the electric motor. 4. The vehicle motion control apparatus according to claim 3, wherein the second rotational speed is determined by the condition of the vehicle and when a pressure increasing rate characteristic determined by the characteristic of the amount of brake fluid and the pressure increasing rate relative to the second rotational speed of the electric motor and by a maximum value of the amount of brake fluid at the second rotational speed is lower than the target pressure increasing rate, the motor controlling means operates the electric motor with a rotational speed being higher than the second rotational speed. 5. A vehicle motion control apparatus according to claim 1, further comprising frictional coefficient detecting means for detecting a frictional coefficient of the road surface as the condition of the road surface, and wherein the lower the frictional coefficient detected by the frictional coefficient detecting means is, the more the motor controlling means reduces the output of the electric motor. 6. A vehicle motion control apparatus according to claim 1, wherein the target pressure increasing rate is specified on a basis of whether or not the vehicle is in an understeering state, whether or not the vehicle is in an oversteering state, or a vehicle speed. 7. The vehicle motion control apparatus according to claim 1, wherein the valve controlling means controls the operation of the solenoid valve by a valve duty ratio calculated on a basis of the output of the electric motor determined by the motor controlling means and a characteristic of the pressure increasing rate and the valve duty ratio for the output of the electric motor determined by the motor controlling means, and when an inclination of the characteristic of the pressure increasing rate and the valve duty ratio for the output of the electric motor determined by the motor controlling means is smaller than an inclination of a reference characteristic indicating a characteristic of the pressure increasing rate and the valve duty ratio defined by the target pressure increasing rate and 100% of the valve duty ratio, the valve controlling means controls the operation of the solenoid valve at 100% of the valve duty ratio and the motor controlling means reduces the output of the electric motor determined by the motor controlling means to the output of the electric motor indicating the reference characteristic. 8. A method for controlling a vehicle motion, comprising: a hydraulic pressure applying step for applying hydraulic pressure to any of wheel cylinders respectively provided at plural wheels of a vehicle by operating a pump for controlling a supply of brake fluid to the wheel cylinder with an electric motor, so as to supply brake fluid to a master cylinder side of any of solenoid valves respectively provided between a master cylinder and the corresponding wheel cylinders and by controlling an operation of the solenoid valve to allow brake fluid to flow from the solenoid valve to a wheel cylinder side of the solenoid valve so that a target pressure increasing rate specified on a basis of a condition of the vehicle is satisfied even when an operator of the vehicle does not operate a brake operation member, wherein hydraulic pressure is applied to the wheel cylinders at a predetermined pressure increasing rate based on the condition of the vehicle regardless of operation of the brake operation member by the operator of the vehicle;a motor controlling step for controlling an output of the electric motor to be reduced in accordance with a condition of a road surface, on which the vehicle drives, when the hydraulic pressure is applied to the wheel cylinder in the hydraulic pressure applying step;a determining step for determining that the output of the electric motor has been reduced; anda valve controlling step for controlling the operation of the solenoid valve to increase an amount of brake fluid allowed to flow from the solenoid valve by the operation of the solenoid valve whenever it is determined that the output of the electric motor has been reduced to maintain the target pressure increasing rate when the output of the electric motor is controlled to be reduced in the motor controlling step,wherein during the hydraulic pressure applying step when a hydraulic pressure is applied to the wheel cylinders at the predetermined pressure increase rate when the operator of the vehicle does not operate the brake operation member, a reduction of the pressure increasing rate relative to the wheel cylinders caused by a reduction of the output of the electric motor in the motor controlling step is compensated with an increase of the pressure increasing rate by controlling the solenoid valve in the valve controlling step to increase the amount of brake fluid allowed to flow to the wheel cylinders. 9. A method for controlling a vehicle motion according to claim 8, wherein the output of the electric motor corresponds to rotational speed of the electric motor and the rotational speed of the electric motor is controlled to be reduced in the motor controlling step, and wherein the amount of brake fluid allowed to flow from the solenoid valve is controlled to be increased in the valve controlling step in accordance with a reduction degree of the rotational speed of the electric motor reduced in the motor controlling step. 10. A method for controlling a vehicle motion according to claim 9, wherein the rotational speed of the electric motor and the amount of brake fluid allowed to flow from the solenoid valve is controlled so as to maintain a target pressure increasing rate determined on the basis of a condition of the vehicle and the amount of brake fluid is set on the basis of a pressure increasing rate and a characteristic predetermined for every rotational speed of the electric motor by the amount of brake fluid and the pressure increasing rate in the hydraulic pressure applying step,and wherein a first rotational speed of the electric motor is changed to a second rotational speed of the electric motor which is lower than the first rotational speed and a first amount of brake fluid is changed to a second amount of brake fluid which is greater than the first amount of brake fluid in the motor controlling step and the valve controlling step so that the second rotational speed and the second amount of brake fluid correspond to the target pressure increasing rate, the first rotational speed and the first amount of brake fluid is set to be the target pressure increasing rate, and the second amount of brake fluid is set on the basis of the target pressure increasing rate and the characteristic predetermined by the amount of brake fluid and the pressure increasing rate relative to the second rotational speed of the electric motor. 11. A method for controlling a vehicle motion according to claim 10, wherein the second rotational speed is determined by the condition of the vehicle and when a pressure increasing rate characteristic determined by the characteristic of the amount of brake fluid and the pressure increasing rate relative to the second rotational speed of the electric motor and by a maximum value of the amount of brake fluid at the second rotational speed is lower than the target pressure increasing rate, the electric motor is controlled to operate with a rotational speed being higher than the second rotational speed in the hydraulic pressure applying step. 12. A method for controlling a vehicle motion according to claim 8, further comprising: a frictional coefficient detecting step for detecting a frictional coefficient of the road surface as the condition of the road surface,wherein the lower the frictional coefficient detected by the frictional coefficient detecting means is, the more the output of the electric motor is reduced in the motor controlling step. 13. A method for controlling a vehicle motion according to claim 8, wherein the target pressure increasing rate is specified on a basis of whether or not the vehicle is in an understeering state, whether or not the vehicle is in an oversteering state, or a vehicle speed. 14. The vehicle motion control apparatus according to claim 8, wherein the valve controlling means controls the operation of the solenoid valve by a valve duty ratio calculated on a basis of the output of the electric motor determined by the motor controlling means and a characteristic of the pressure increasing rate and the valve duty ratio for the output of the electric motor determined by the motor controlling means, and when an inclination of the characteristic of the pressure increasing rate and the valve duty ratio for the output of the electric motor determined by the motor controlling means is smaller than an inclination of a reference characteristic indicating a characteristic of the pressure increasing rate and the valve duty ratio defined by the target pressure increasing rate and 100% of the valve duty ratio, the valve controlling means controls the operation of the solenoid valve at 100% of the valve duty ratio and the motor controlling means reduces the output of the electric motor determined by the motor controlling means to the output of the electric motor indicating the reference characteristic.