Nippon a B S, Ltd.

Nippon Air Brake Co., Ltd.

Tetsuro Arikawa

Yasuo Samatsu

Teruo Inoue

Toshiyuki Abe

Hideyuki Yamada

Yukihiro Takiue

Atsumu Harada

In a fluid-pressure control apparatus for anti-skid control apparatus, including a control unit for generating brake control signals corresponding to the rotational behaviors of the respective wheels and valve control signals on the basis of the 2 outputs of the wheel speed sensors; and fluid pressure control valves arranged in the respective brake conduit systems and operated by the valve control signals the brake control signals from the front wheels are preferentially used to those from the rear wheels as the valve control signals in the respective brake conduit systems, and when the brake control signal is generated fron any one of the front wheels, the fluid pressure control valve in the one brake conduit system to which the one front wheel belongs, is operated by using the brake control signal as the valve control signal; and when the brake control signal is generated from any one of the rear wheels, the fluid pressure control valve in the one brake conduit system to which the one rear wheel belongs, is operated by using the brake control signal as the valve control signal, if the following condition (a) or (b) is fulfilled: (a) the condition that the vehicle deceleration is larger than a predetermined reference deceleration and the straight-running of the vehicle is detected; (b) the condition that the vehicle deceleration is larger than a predetermined reference deceleration and slip of the other rear wheel is larger than a predetermined first reference slip.

Anti-skid brake control method

A fluid pressure brake control apparatus for controlling braking-slip and driving-slip of wheels includes fluid pressure control valves, a fluid pressure pump and a valve apparatus arranged between the fluid pressure control valves and the master cylinder, and between the fluid pressure control valves and a fluid pressure source. In a first condition the fluid pressure valving is connected with the master cylinder while being cut off from the fluid pressure source. In a second condition the fluid pressure control valving is connected with the fluid pressure source while being cut off from the master cylinder. In a third condition the fluid pressure control valving is cut off from both the master cylinder and the fluid pressure source. The apparatus assumes the second condition during driving-slip control and supplies to the fluid pressure source the pressurized brake fluid discharged from the fluid pressure pump.

Fluid pressure brake control apparatus for vehicle

A brake adjusting apparatus for a vehicle includes an engine brake detector for detecting that the engine brake is applied; a drive wheel speed detector for detecting speed or acceleration of a drive wheel; a reference drive wheel speed setting circuit for setting a reference drive wheel speed or reference drive wheel acceleration to be compared with the output of the drive wheel speed detector; and an idle speed controller for controlling an idle speed of the engine, wherein the idle speed controller is so adjusted that the drive wheel is rotated at the reference drive wheel speed or the reference drive wheel acceleration, when engine brake application is detected by the engine brake detector.

Apparatus for controlling engine idle speed in a vehicle having an

An anti-skid control apparatus for a vehicle includes fluid pressure control valve devices arranged between fluid pressure generating chambers of a tandem master cylinder and the wheel cylinders of the front wheels, respectively, and a control unit receiving outputs of wheel speed sensors for measuring or judging the skid conditions of the front and rear wheels and for generating instructions for controlling the fluid pressure control valve devices. The control unit discriminates the frictionally lower side of the road on which the wheels are running, on the basis of the measuring or judging results of the skid conditions of the rear and/or front wheels, combines logically the measuring or judging result of the skid condition of the one rear wheel running on the low side of the road or the measuring or judging results of the skid conditions of the rear wheels, with that of the one front wheel running on the low side, for generating the instruction for controlling the first or second fluid pressure control valve device for the corresponding front wheel, and generates the instruction for controlling the second or first fluid pressure control valve device for the other front wheel, on the basis of the measuring or judging result of the skid condition of the measuring or judging result of the skid condition of the other front wheel running on the high side independently of those of the rear wheels. The low side can be changed over in accordance with the measuring or judging result. Or the control unit will reset the low side.

Anti-skid control apparatus for a vehicle braking system

An anti-skid control apparatus for a vehicle includes fluid pressure control valve devices arranged between a tandem master cylinder and the front wheels of the vehicle, and a control unit receiving outputs of wheel speed sensors to assess skid conditions of the wheels and to control the valve devices. The apparatus discriminates between 'low side' and 'high side' of the road by assessing skid conditions of either the rear wheels or the front wheels. The braking pressure of the rear or front wheel that is on the low side and that of the wheel connected diagonally to it are controlled in either a 'select-high' or a 'select-low' manner, and the pressures of the other diagonally opposite wheels are controlled in the opposite manner. In the alternative, the apparatus may assess the skid condition of the one rear wheel based on the larger of the braking frictional coefficients of the sides of the road, on the basis of the acceleration and slip conditions of the one rear wheel, while it judges the skid condition of the other rear wheel on the smaller one of the braking frictional coefficients of the sides of the road only on the basis of the acceleration condition of the other rear wheel, and the braking pressures of the respective conduit systems are controlled in the select-low manner.

In a brake fluid pressure control apparatus for vehicle which controls braking slip and driving slip of wheels, first and second brake conduits are arranged for connecting a master cylinder with a wheel cylinder, respectively. A fluid pressure control valve is arranged in the first brake conduit for controlling the brake fluid pressure of the wheel. Between a main conduit for connecting the master cylinder with the fluid pressure control valve, and the second brake conduiut, a valve apparatus is arranged for connecting the master cylinder with the fluid pressure control valve and cutting off the master cylinder from the second brake conduit normally and during the braking slip control operation, and for cutting off the master cylinder from the fluid pressure control valve and connecting the master cylinder with the second brake conduit during the driving slip control. A check valve is arranged so as to permit brake fluid to flow from the master cylinder side towards the wheel cylinder side.

Brake fluid pressure control apparatus for a vehicle

A control unit for judges braking slip and/or driving slip of front and rear wheels. Fluid pressure control valve devices receive instructions from the control unit for controlling brake fluid pressure of the front and rear wheel brake apparatuses. A first fluid pressure pump pressurizes and supplies brake fluid from hydraulic reservoirs into main conduits connecting a tandem master cylinder with the fluid pressure control valve devices. A first valve device is arranged between the tandem master cylinder and the first fluid pressure pump in the main conduit means connected through the fluid pressure control valve devices to front and/or rear brake apparatuses. The first valve device is normally in free communication and changed over into a position to prohibit brake fluid to flow from the discharging side of the first fluid pressure pump towards the master cylinder side under a first predetermined condition. A second valve device is arranged between the master cylinder and first fluid pressure pump in main conduits connected through the control valve devices at least to the front brake apparatus. The second valve device is normally in free communication and changeable into a position to prevent brake fluid having the discharging side of the first fluid pressure pump towards the master cylinder side under a second predetermined condition. The hydraulic reservoirs consist of a first hydraulic reservoir for previously reserving brake fluid and a second hydraulic reservoir. A second fluid pressure pump is arranged in a conduit connecting the first hydraulic reservoir with the second hydraulic reservoir, the discharging side of which is directed to the suction side of the first fluid pressure pump.

Fluid pressure brake control apparatus for a vehicle

A brake fluid pressure control apparatus for a vehicle includes a fluid pressure control valve device arranged between a master cylinder and a wheel cylinder, receiving control signals from a control unit measuring the skid condition of the wheel to control the brake fluid pressure to the wheel cylinder. A hydraulic reservoir stores the brake fluid discharged through the fluid pressure control valve device from the wheel cylinder and a pressure fluid supply conduit connects the master cylinder with the fluid pressure control valve device. A fluid pump returns the brake fluid from the hydraulic reservoir into the pressure fluid supply conduit and a valve apparatus is arranged in a conduit connecting the discharge side of the fluid pump with the master cylinder side, in the pressure fluid supply conduit. The valve apparatus takes a first position connecting both sides and a second position that cuts off the fluid flow from the discharging side of the fluid pump toward the master cylinder side. The valve apparatus is normally in the first position. During anti-skid control, it takes the first position continuously for a certain time depending on the control time of the fluid pressure decrease and continuously for another certain time depending on the control time if the fluid pressure is increased after the fluid pressure decrease, and it takes the second position continously for times other than the certain time and/or the other certain time. Alternatively, it cycles between the first and second position for a certain time depending on the control time of the fluid pressure decrease and/or for another certain time depending on the control time of increasing again the fluid pressure after the fluid pressure decrease, and it takes the second position for times other than the certain time and/or the another certain time.

An anti-skid control apparatus for a vehicle having a brake system in which the front wheels are diagonally connected with the rear wheels, including a fluid pressure control valve device arranged between fluid pressure generating chambers of a tandem master cylinder and the wheel cylinders of the front wheels and a valve apparatus arranged between the wheel cylinder of the front wheels and those of the rear wheels. Fluid pressure is supplied to the rear wheels in accordance with the lower one of the brake fluid pressure onf the front wheels controlled by the fluid pressure control valve devices. The measuring or judging results of the skid conditions of the front and rear wheels on the same side of the vehicle are logically combined with each other to control the fluid pressure control valve devices.

Anti-skid control apparatus for braking system

An anti-skid control apparatus for a vehicle braking system in which wheel cylinders for front and rear wheels are diagonally connected in conduits includes a first fluid pressure control valve device for controlling the brake fluid pressure of the wheel cylinder of one of the front wheels or rear wheels is arranged between a first fluid pressure generating chamber of a tandem master cylinder and said wheel cylinder of the one front or rear wheel. A second fluid pressure control valve device for controlling the brake fluid pressure of the wheel cylinder of another of the front wheels or rear wheels is arranged between a second fluid pressure generating chamber of said tandem master cylinder and the wheel cylinder of the other front or rear wheel. Each of the first and second fluid pressure control valve devices consists of a three-port two-position change-over valve connected to the master cylinder side and a two-port two-position change-over valve connected in series with the three-port two-position change-over valve and the conduit connecting the three-port two-position change-over valve with the two-port two-position change-over valve being connected to the wheel cylinder of the one or other front or rear wheel of the corresponding conduit system and first judging results for relieving the brake of the front and rear wheels are logically combined with second judging results for maintaining the braking of the first and rear wheels constant, for generating instructions to control the change-over valves.

Anti-skid control apparatus for vehicle braking system

In an anti-skid control apparatus for a four-wheeled vehicle, fluid pressure control valve devices are arranged in the respective brake conduits, and a control unit determines which side of the road has a lower coefficient of friction. This side is called the low side. The fluid pressure control valve device connected to the one front wheel on the low side effects brake relieving control on the basis of the brake relieving signal of the one of the front and rear wheels on the low side which has generated the brake relieving signal sooner than the other. In the alternative, it effects brake relieving control on the basis of the brake relieving signal of the one or ones of the front wheels on the low side of the rear wheels which has generated the brake relieving signal sooner than the other or others.

In an anti-ski control apparatus for a vehicle braking system including fluid pressure control valve devices and a valve apparatus, when brake-relieving output signals are obtained from both rear wheels, the brake-relieving output signal of the one of the rear wheels that is obtained later than that of the other is combined logically with the brake-relieving output signal of the one of the front wheels running on the same side as the one rear wheels to form a brake-relieving control signal for controlling a first or second fluid pressure control valve device connected to the wheel cylinder of the one front wheel. A brake-increasing control signal is generated by the first or second fluid pressure control valve device after the brake-relieving control signal disappears based on the brake-increasing output signal of the one of the front and rear wheels on the same side which has a stronger locking tendency than the other. In the alternative, the signal is formed based on the brake-increasing output signal of the one of the front and rear wheels on the same side, the acceleration of which is smaller than that of the other. A brake-holding control signal by the first or second fluid pressure control valve device, before the brake-relieving control signal generates, is formed by logical sum (OR) of the brake-holding output signals of the one front and rear wheels on the same side, and a brake-increasing control signal by the first or second fluid pressure control valve device, after the brake-relieving control signal disappears, is formed on the basis of the brake-increasing output signal of the one of the one front and rear wheels on the same side the brake-holding output signal of which has generated sooner than that of the other.

An anti-skid control apparatus includes a master cylinder, a fluid pressure control valve for controlling fluid pressures of wheel cylinders connected to one of two brake conduit circuits, and a valve apparatus for controlling fluid pressure of wheel cylinders connected to the other of the two brake conduit circuits. The valve apparatus includes a casing having first and second input ports, an output port, a piston, a control chamber and a volume chamber formed at both sides of the piston. A valve part is disposed between the first input port and the volume chamber, the first input port being connected to one fluid pressure generating chamber of the master cylinder and the output port being connected to the wheel cylinders that are connected to the other of the two brake conduit circuits. A changeover valve is connected to the second input port. The changeover valve is set either in a first position for connecting another fluid pressure generating chamber of the master cylinder to the control chamber or else a second position for connecting the output side of the fluid pressure control valve with the control chamber. When the changeover valve is in the first position, the valve part is open, and when the changeover valve is in the second position and the fluid pressure control valve is operated, the piston is moved toward the control chamber to close the valve part so as to cut off the first input port from the volume chamber and change the volume of the volume chamber.

Anti-skid control apparatus includes wheel speed sensors for front and rear wheels. First and second fluid pressure control valve devices control brake fluid pressures of wheel cylinders of the front and rear wheels, arranged between fluid pressure generating chambers of a tandem master cylinder and the wheel cylinders respectively. A control unit receives outputs of the sensors for measuring or judging the skid conditions of the wheels and for generating instructions for controlling the valve devices. A valve apparatus generates fluid pressure in accordance with the lower one of the brake fluid pressures of the front wheels controlled with the valve devices arranged between the wheel cylinders of the front wheels and those of the rear wheels. When the wheel speed difference between the front and rear wheels on the same side of the road becomes larger than a predetermined value, or when the deceleration of the one rear wheel becomes larger than a predetermined deceleration for the one rear wheel which is smaller than a second predetermined deceleration for the one front wheel running on the same side as the one rear wheel, before the one front or rear wheel on the same side first generates a brake relieving signal, the control unit generates the instruction which controls the first or second fluid pressure control valve device for the same side so as to maintain the pressure constant, or to reduce the rising gradient of the pressure.

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Kanagawa, Japan

Tetsuro Arikawa