Abstract: A brake fluid pressure electrically generated by a slave cylinder (23) in accordance with an operation amount by a brake pedal (12) is supplied via a VSA system (24) to wheel cylinders (16, 17; 20, 21) provided respectively for wheels. This enables smooth braking by the wheel cylinders (16, 17; 20, 21) by using a brake fluid pressure pressurized by the slave cylinder (23) and including little pulsation. When the VSA system (24) is to individually control the brake fluid pressures supplied respectively to the wheel cylinders (16, 17; 20, 21) to control vehicle behavior, the slave cylinder (23) generates a brake fluid pressure corresponding to a total of the brake fluid pressures required for the wheel cylinders (16, 17; 20, 21). This configuration allows the slave cylinder (23) to generate a brake fluid pressure in just proportion.

Abstract: A brake device for a vehicle is provided in which when there is an abnormality in which a slave cylinder becomes incapable of being actuated, a wheel cylinder is actuated using a brake fluid pressure generated by a master cylinder, which is actuated by a brake pedal. Since an idling detector detects idling of a motor when the rotational speed of the motor is greater than a reference value that is set according to the stroke of the slave cylinder, it is possible to reliably and rapidly detect idling of the motor. When the idling of the motor is detected, since a control device opens a master cut valve and the wheel cylinder is actuated by the brake fluid pressure generated by the master cylinder, the slave cylinder, which has become incapable of being actuated, can be backed up rapidly by the master cylinder.

Abstract: In a brake-by-wire vehicle brake system using a feedback control unit (12a, 12b, 31, 36, 45) for producing a brake fluid pressure according to a brake input, a response restricting unit (26, 39, 48) restricts a response property of the feedback control unit when an extraneous brake fluid control operation is detected. Thereby, the control unit is prevented from excessively reacting to changes in the brake fluid pressure caused by the extraneous brake fluid control operation, and the vehicle brake system can provide a highly responsive property and a resistance to changes in the brake fluid pressure at the same time.

Abstract: Upon occurrence of a change in the load versus fluid loss property, the braking force for the given brake pedal operation amount is changed so that the vehicle operator is enabled to perceive the change in the load versus fluid loss property. In a vehicle brake system comprising a motor actuated cylinder, wheel cylinders, a stroke sensor for detecting a brake pedal operation amount, a target value setting circuit for setting a target stoke of the motor actuated cylinder, and a fluid pressure compensating circuit for correcting the target stoke upon detection of a deviation between a brake fluid pressure reference value corresponding to the brake pedal operation amount and an actual brake fluid pressure in a direction to reduce the deviation, a stroke limiting circuit restricts a compensation value produced by the fluid pressure compensation circuit according to the brake pedal operation amount.

Abstract: In a BBW type vehicle brake device, first and second fluid paths that are connected to each other are both connected to a slave cylinder with a simple structure that is equipped with a single fluid pressure chamber, thereby enabling wheel cylinders having two lines to be operated and eliminating the need for a complicated tandem type slave cylinder. When the slave cylinder becomes inoperable due to malfunction of the power supply, by opening first and second master cut valves and closing the communication control valve, braking is carried out by means of brake fluid pressure generated by a master cylinder. In this process, since the interconnection between the first and second fluid paths is blocked by closing the communication control valve, even if the wheel cylinder of one of the brake lines suffers from a liquid leakage malfunction, the other remained brake line is enabled to ensure a braking force.

Abstract: In a BBW type brake device, if a slave cylinder becomes inoperable, when a master cylinder is operated for the first time, a master cut valve is opened to charge brake fluid into a reservoir of a hydraulic modulator, and since the brake fluid charged into the reservoir is increased in pressure by driving a hydraulic pump when the master cut valve is closed, wheel cylinders are operated. Since the amount of brake fluid on the downstream side relative to the master cut valve is increased by charging the reservoir with brake fluid, it is possible to increase the pressure of the brake fluid of the reservoir by driving the hydraulic pump and generate brake fluid pressure by a hydraulic modulator that is higher than the brake fluid pressure generated by the master cylinder, thereby generating sufficient braking force without increasing the depressing force applied to a brake pedal.

Abstract: When brake fluid of a first wheel cylinder (39a) of a slave cylinder (23) is increased by supplying the brake fluid to a first wheel cylinder (16, 17) by a first pump (64A), a second piston (38B), which is a free piston, of the slave cylinder (23) moves toward the first fluid pressure chamber (39A) side, the volume of a second fluid pressure chamber (39B) thereby expands, and the brake fluid pressure of a second wheel cylinder (20, 21) can be reduced, whereas when brake fluid pressure of the second fluid pressure chamber (39B) is increased by supplying the brake fluid to the second wheel cylinder (20, 21) by a second pump (64B), the second piston (38B) moves toward the second fluid pressure chamber (39B) side, the volume of the first fluid pressure chamber (39A) thereby expands, and the brake fluid pressure of the first wheel cylinder (16, 17) can be reduced, thus enabling a difference in brake fluid pressure to be freely generated between the first and second wheel cylinders (16, 17).

Abstract: A brake device for a vehicle is provided in which when there is an abnormality in which a slave cylinder becomes incapable of being actuated, a wheel cylinder is actuated by means of a brake fluid pressure generated by a master cylinder, which is actuated by a brake pedal. Since idling detection means detects idling of a motor when the rotational speed of the motor is greater than a reference value that is set according to the stroke of the slave cylinder, it is possible to reliably and rapidly detect idling of the motor. When the idling of the motor is detected, since control means opens a master cut valve and the wheel cylinder is actuated by means of the brake fluid pressure generated by the master cylinder, the slave cylinder, which has become incapable of being actuated, can be backed up rapidly by the master cylinder.

Abstract: Upon occurrence of a change in the load versus fluid loss property, the braking force for the given brake pedal operation amount is changed so that the vehicle operator is enabled to perceive the change in the load versus fluid loss property. In a vehicle brake system comprising a motor actuated cylinder, wheel cylinders, a stroke sensor for detecting a brake pedal operation amount, a target value setting circuit for setting a target stoke of the motor actuated cylinder, and a fluid pressure compensating circuit for correcting the target stoke upon detection of a deviation between a brake fluid pressure reference value corresponding to the brake pedal operation amount and an actual brake fluid pressure in a direction to reduce the deviation, a stroke limiting circuit restricts a compensation value produced by the fluid pressure compensation circuit according to the brake pedal operation amount.

Abstract: A vehicle brake mechanism includes a master cylinder operated with a brake pedal. A first fluid channel connects a first hydraulic chamber of the master cylinder to a first-circuit wheel cylinder. A second fluid channel connects a second hydraulic chamber of the master cylinder to a second-circuit wheel cylinder. A master cut valve is provided in the first fluid channel and is capable of hindering communication between the first hydraulic chamber and the first-circuit wheel cylinder. A slave cylinder is connected to the second fluid channel and is driven by an actuator to generate a hydraulic pressure. A third fluid channel is provided downstream of the master cut valve and the slave cylinder and connects the first fluid channel and the second fluid channel to each other. A connection control valve is provided in the third fluid channel to close the third fluid channel.

Abstract: In a BBW type brake device, if a slave cylinder becomes inoperable, when a master cylinder is operated for the first time, a master cut valve is opened to charge brake fluid into a reservoir of a hydraulic modulator, and since the brake fluid charged into the reservoir is increased in pressure by driving a hydraulic pump when the master cut valve is closed, wheel cylinders are operated. Since the amount of brake fluid on the downstream side relative to the master cut valve is increased by charging the reservoir with brake fluid, it is possible to increase the pressure of the brake fluid of the reservoir by driving the hydraulic pump and generate brake fluid pressure by a hydraulic modulator that is higher than the brake fluid pressure generated by the master cylinder, thereby generating sufficient braking force without increasing the depressing force applied to a brake pedal.

Abstract: In a BBW type vehicle brake device, first and second fluid paths that are connected to each other are both connected to a slave cylinder with a simple structure equipped with a single fluid pressure chamber, thereby enabling wheel cylinders having two lines to be operated and eliminating the need for a complicated tandem type slave cylinder. When the slave cylinder becomes inoperable due to malfunction of the power supply, by opening first and second master cut valves and closing the communication control valve, braking is carried out by brake fluid pressure generated by a master cylinder. In this process, since the interconnection between the first and second fluid paths is blocked by closing the communication control valve, even if the wheel cylinder of one of the brake lines suffers from a liquid leakage malfunction, the other remained brake line is enabled to ensure a braking force.

Abstract: A slip angle differential value calculation unit 34 calculates a slip angle differential value of a body of a vehicle, a braking force application prohibiting unit 35 prohibits the application of braking force by a braking force application unit 33 when a yaw rate detection value takes a positive value and the sip angle differential value is a positive judgment threshold or more or when the yaw rate detection value takes a negative value and the slip angle differential value is a negative judgment threshold or less.

Abstract: In a brake-by-wire vehicle brake system using a feedback control unit (12a, 12b, 31, 36, 45) for producing a brake fluid pressure according to a brake input, a response restricting unit (26, 39, 48) restricts a response property of the feedback control unit when an extraneous brake fluid control operation is detected. Thereby, the control unit is prevented from excessively reacting to changes in the brake fluid pressure caused by the extraneous brake fluid control operation, and the vehicle brake system can provide a highly responsive property and a resistance to changes in the brake fluid pressure at the same time.

Abstract: A vehicular anti-lock control system includes: a ground load calculation section for detecting or estimating a ground load of a wheel; a road surface friction coefficient calculation section for detecting or estimating a road surface friction coefficient; and a reference fluid pressure calculation section for calculating an upper side reference fluid pressure and a lower side reference fluid pressure in anti-lock control based on the ground load and the friction coefficient. The upper and lower side reference fluid pressures are respectively determined to be an upper limit value and a lower limit value of a fluid pressure in anti-lock control. Therefore, it is possible to suppress the amount of change in the fluid pressure during anti-lock control, thus improving the braking effect and the braking feel.

Abstract: A brake fluid pressure electrically generated by a slave cylinder (23) in accordance with an operation amount by a brake pedal (12) is supplied via a VSA system (24) to wheel cylinders (16, 17; 20, 21) provided respectively for wheels. This enables smooth braking by the wheel cylinders (16, 17; 20, 21) by using a brake fluid pressure pressurized by the slave cylinder (23) and including little pulsation. When the VSA system (24) is to individually control the brake fluid pressures supplied respectively to the wheel cylinders (16, 17; 20, 21) to control vehicle behavior, the slave cylinder (23) generates a brake fluid pressure corresponding to a total of the brake fluid pressures required for the wheel cylinders (16, 17; 20, 21). This configuration allows the slave cylinder (23) to generate a brake fluid pressure in just proportion.

Abstract: When brake fluid of a first wheel cylinder (39a) of a slave cylinder (23) is increased by supplying the brake fluid to a first wheel cylinder (16, 17) by a first pump (64A), a second piston (38B), which is a free piston, of the slave cylinder (23) moves toward the first fluid pressure chamber (39A) side, the volume of a second fluid pressure chamber (39B) thereby expands, and the brake fluid pressure of a second wheel cylinder (20, 21) can be reduced, whereas when brake fluid pressure of the second fluid pressure chamber (39B) is increased by supplying the brake fluid to the second wheel cylinder (20, 21) by a second pump (64B), the second piston (38B) moves toward the second fluid pressure chamber (39B) side, the volume of the first fluid pressure chamber (39A) thereby expands, and the brake fluid pressure of the first wheel cylinder (16, 17) can be reduced, thus enabling a difference in brake fluid pressure to be freely generated between the first and second wheel cylinders (16, 17).

Abstract: A vehicle brake mechanism includes a master cylinder operated with a brake pedal. A first fluid channel connects a first hydraulic chamber of the master cylinder to a first-circuit wheel cylinder. A second fluid channel connects a second hydraulic chamber of the master cylinder to a second-circuit wheel cylinder. A master cut valve is provided in the first fluid channel and is capable of hindering communication between the first hydraulic chamber and the first-circuit wheel cylinder. A slave cylinder is connected to the second fluid channel and is driven by an actuator to generate a hydraulic pressure. A third fluid channel is provided downstream of the master cut valve and the slave cylinder and connects the first fluid channel and the second fluid channel to each other. A connection control valve is provided in the third fluid channel to close the third fluid channel.

Abstract: A slip angle differential value calculation unit 34 calculates a slip angle differential value of a body of a vehicle, a braking force application prohibiting unit 35 prohibits the application of braking force by a braking force application unit 33 when a yaw rate detection value takes a positive value and the sip angle differential value is a positive judgment threshold or more or when the yaw rate detection value takes a negative value and the slip angle differential value is a negative judgment threshold or less.