Abstract: An operated quantity of a brake pedal is detected based on a signal from a stroke sensor. A starting criterion to start brake assisting is determined with respect to an operational speed of the brake pedal in response to the operated quantity of the brake pedal. An operated-quantity change is calculated by differentiating the operated quantity of the brake pedal. It is determined whether the operated-quantity change exceeds the starting criterion. If the operated-quantity change exceeds the starting criterion, brake assisting is started by driving a pump to increase wheel cylinder pressure.

Abstract: A brake booster includes a solenoid disposed within a valve body. When the solenoid is energized under the inoperative condition of the brake booster, a piston associated with the solenoid is moved to its operative position to close a vacuum valve while opening an atmosphere valve. This allows the brake booster to be operated as an automatic brake without depressing a brake pedal. The brake booster also comprises output restriction means which may comprise a spring 55 shown in FIG. 1, for example, whereby as the output increases when the brake booster is operated as an automatic brake, the output restriction means operates to cease an increase in the output. With this arrangement, if the solenoid is energized inadvertently independently from the intent of a driver, the occurrence of a quick braking action is avoided, but a gentle braking action is assured, thus improving the safeguard.

Abstract: A hydraulic circuit has a rotary type pump comprising a rotor rotating with a driving shaft and a casing which holds the rotor and the driving shaft. The casing further comprises an inlet port through which fluid is introduced to spaces formed by the rotor, an outlet port through which fluid is discharged from the spaces, and a hydraulic path for leading fluid from clearance around said driving shaft to the outside of the casing. A reservoir is provided to store fluid coming through the hydraulic path. A return conduit is disposed between the reservoir and an upstream side conduit connected to the inlet port in order that fluid stored in the reservoir is returned to the upstream side conduit. In the return conduit, a check valve is disposed to prevent the reverse flow of fluid from the upstream side conduit to the reservoir.

Abstract: A turning state of a vehicle is detected to specify an outer side front wheel and an inner side rear wheel of a turning circle. A controlling device controls the brake fluid pressures of wheel cylinders of the specified wheels so that the brake fluid pressure of the wheel cylinder of one of the specified wheels is made smaller than a master cylinder pressure while substantially simultaneously the brake fluid pressure of the wheel cylinder of the other wheel of the specified wheels is made larger than the master cylinder pressure.

Abstract: A tandem brake booster includes a solenoid within a valve body, and the solenoid may be energized to move a first tubular member disposed on the valve body rearward. When an input shaft is driven forward in the inoperative condition of the brake booster, a vacuum valve is closed while an atmosphere valve is opened in the similar manner as occurs in the prior art, thus actuating the tandem brake booster 1. When an input or the force of depression applied to a brake pedal rises to a given value X during the operative condition of the brake booster, the solenoid is energized, whereupon the first tubular member is moved rearward relative to the valve body, and the valve element is also moved rearward. This opens the atmosphere valve which has been closed during the servo balance condition, allowing a further introduction of the atmosphere into variable pressure chambers B, D, enabling a rise in the output even though the input remains unchanged.

Abstract: A brake booster which permits an axial relative movement between a power piston and a valve body is disclosed. An arrangement is made which prevents a brake reaction from being transmitted to a brake pedal. As an alternative therefor, pseudo-reaction imparting means transmits a pseudo-reaction to a brake pedal. A rear end of the valve body is covered by a tubular cover and bellows connected thereto, and its internal space is maintained in communication with a constant pressure chamber. The bellows has an effective diameter which is chosen to be of an equal size to the diameters of a vacuum valve seat and an atmosphere valve seat. This allows a pseudo-reaction and a brake pedal stroke to be obtained which depend on the force with which a brake pedal is depressed if a negative pressure within the constant pressure chamber varies, thus imparting a better brake feeling to a driver.

Abstract: An automatic brake booster includes a solenoid which drives a plunger, forming part of a valve mechanism, forward to switch a flow path in the valve mechanism, separately from an input shaft. A piston is mounted on the plunger, and the atmospheric pressure is introduced into an atmospheric pressure chamber disposed forwardly of the piston while a pressure which prevails in constant pressure chambers A, C is introduced into a negative pressure chamber disposed rearwardly of the piston, thus urging the piston rearward. Preferably, the piston has a pressure responsive area which is substantially equal to the pressure responsive area of an atmosphere valve seat formed on a plunger. This arrangement allows a variation in the output from the brake booster to be minimized or reduced substantially to zero if there is a variation in the magnitude of a negative pressure which is introduced into the constant pressure chambers A, C.

Abstract: A brake system has wheel cylinders for producing a braking force in wheels using pressurized brake fluid transmitted through a main conduit from a master cylinder, a reservoir for storing brake fluid, a sideslip preventing device for when a sideslip state of the vehicle is detected supplying brake fluid to the wheel cylinder corresponding to a sideslip controlled wheel and producing a braking force in the sideslip controlled wheel, a first conduit used for supplying brake fluid from the reservoir to the wheel cylinders by the pump and a first valve for switching this first conduit between an open state and a closed state. The sideslip preventing device, when the sideslip state is detected during non-braking of the vehicle, makes the first valve open-state and thereby conducts supply of brake fluid through the first conduit from the reservoir to the wheel cylinder by a pump.

Abstract: A wheel load of each wheel or a vehicle body load is estimated based on a gain of a resonance frequency of a tire, and the estimated wheel load or vehicle body load is applied to a braking control or an acceleration control. Further, a ground contact load of each wheel or the vehicle body load of the vehicle is estimated based on the gain of the resonance frequency extracted from each of the tires for use in a vehicle control.

Abstract: During a time period of from a time that is immediately before a vehicle being stopped to a time of the vehicle being stopped, a pressure increase gradient in braking fluid pressure which is applied to wheel cylinders of rear wheels is made to be larger than a pressure increase gradient that prevailed until a time that was immediately before the vehicle being stopped. As a result, a pitching motion that occurs in a vehicle body can be suppressed.

Abstract: A first fluid line couples first and second wheel cylinders. A second fluid line couples third and fourth wheel cylinders. A first pressure increasing unit increases pressure applied to the first and second wheel cylinders to a second pressure level which is greater than a first pressure generated by a master cylinder. When the first pressure increasing unit is in operation, a pressure difference setting unit sets a difference between pressure applied to the first and second wheel cylinders and pressure applied to the third and fourth wheel cylinders.

Abstract: A brake control apparatus for a vehicle employs a pressure-amplifying device which reduces a quantity of brake fluid generating a first brake-fluid pressure in a first conduit connected to a master cylinder, and increases second brake-fluid pressure in a second conduit, applied to a wheel cylinder simultaneously with the reduction in brake-fluid quantity in the first conduit. As a result, increase in the first brake-fluid pressure is suppressed even when a driver depress a brake pedal and load to generate the first brake-fluid pressure is alleviated. Additionally, the pressure-amplifying device applies the increased second brake-fluid pressure to the wheel cylinder. Therefore, it is possible to ensure sufficient braking force.

Abstract: A vehicle braking system can, for example when the performance of a booster has deteriorated, reduce a brake pedal depressing force required to obtain a sufficient braking force and thereby lighten the burden on the driver. A booster and a master cylinder generate a brake fluid pressure in correspondence with an operation of a brake pedal. Wheel cylinders connected to the master cylinder generate wheel braking forces in wheels of the vehicle. It is determined if a vehicle braking state corresponds to a state of operation of the brake pedal, and when it is determined that the vehicle braking state does not correspond to the brake pedal operation brake fluid pressure in the wheel cylinders is increased with a pump. In this way, it is possible to obtain a predetermined braking force corresponding to the brake pedal operation at all times.

Abstract: A pressure difference is formed between a master cylinder pressure and a wheel cylinder pressure when a master cut-off valve closes a hydraulic path connecting a master cylinder and a wheel cylinder and a hydraulic pump supplies pressurized brake fluid to the wheel cylinder. After the pressure difference has been formed, the master cut-off valve opens the hydraulic path so that the pressure difference is cancelled. As a result, pulsations in brake fluid pressure occurs in the hydraulic path. A failure of the master cut-off valve or the hydraulic pump is detected based on the pulsations in brake fluid pressure.

Abstract: A total conductance time with respect to each of control actuators is calculated. It is determined whether each of the control actuators has reached a replacement period by determining whether the total conductance time has exceeded a determination value representing an appropriate replacement period. Notification of a control actuator which has been determined to have reached the replacement period is performed by causing a notification light to be illuminated.

Abstract: A traction control system for an automotive vehicle is provided which controls engine power and braking force to recover traction of wheels when wheel slippage occurs during acceleration. The traction control system has four traction control modes and four control switching modes for switching between the traction control modes smoothly without any mechanical shock. In each of the control switching modes, one of the engine power control and the braking force control is restricted gradually according to its control capacity which is, for example, determined based on a period of time left until the control is prohibited. If the control capacity is decreased undesirably, the control is modified so as to increase the control capacity.

Abstract: A braking system for automotive vehicles is provided which is designed to minimize the kickback produced in a brake master cylinder and transmitted to a vehicle operator through a brake pedal during braking control or to inform the vehicle operator of generation of the kickback in advance for alleviating the discomfort due to the kickback. The braking system includes a pressure regulating valve which restricts transmission of a pressure variation to the master cylinder from a hydraulic braking circuit during the braking control to reduce the kickback. The braking system may alternatively include a pressure-reducing valve which reduces the hydraulic pressure within the brake master cylinder to decrease a hydraulic reaction force against the pedal effort provided by the vehicle operator when a wheel is approaching or has reached a road-tire adhesion limit for warning the vehicle operator of generation of the kickback in advance.

Abstract: A brake apparatus for a vehicle that increases brake-fluid pressure at a wheel or wheels whereat adjustment of brake-fluid pressure by the brake-fluid pressure adjusting device has not yet been initiated, at a time when braking control, i.e., adjustment of brake-fluid pressure by a brake fluid pressure adjusting device, is initiated at a wheel. Consequently, braking force of the wheels not under braking control is increased without additional braking operation by the driver, and substantially maximum braking force can be exhibited at the wheels not under braking control.

Abstract: A booster and a pressure amplifying device are provided as devices performing a brake assist. Further a pressure sensor which detects master-cylinder pressure is provided. While the braking is applied to the vehicle, the malfunction of the booster can be detected based on master-cylinder pressure detected by the pressure sensor. If the malfunction of the booster is detected, a pump in the pressure amplifying device is driven as an substitute for the booster. As a result, a required brake assist can be performed to ensure high braking force. Accordingly, the brake control apparatus can enhance safety during vehicle operation.

Abstract: In the present invention, when the wheel speeds of drive wheels are reduced by an engine brake, there are executed drive wheel control for adjusting the braking forces applied to the drive wheels by the engine brake, and driven wheel control for reducing the wheel speeds of driven wheels by an brake actuator. Drive wheel control raises lateral resistant force of the drive wheels by increasing an engine output torque, and driven wheel control brakes the driven wheels by the brake actuator such as a hydraulic brake. As a result, sufficient deceleration of a vehicle can be obtained while retaining the stability of the vehicle.