Honda Giken Kogyo Kabushiki Kaisha

Nissin Kogyo Co., Ltd.

Kazutoshi Tashima

Shohei Matsuda

Jiro Suzuki

Masaaki Myoi

Kohichi Furuya

Yoshihiro Urai

Takeshi Kojima

Makoto Horiuchi

Toshio Yahagi

Kenji Hattori

Tsuyoshi Sato

Tsuyoshi Satoh

Ysuyoshi Satoh

Ryuji Horiuchi

A fluid pressure control device has a sliding member fitted in a housing for switching over the connection and the disconnection between an input port connected to a fluid pressure supply source, an output port connected to a fluid pressure operated device and a release port connected to a reservoir; a reaction chamber for generating a fluid pressure urging the sliding member in a retracting direction; an urging piston operatively connected to the rear end of the sliding member; an input piston operatively connected to an operation member; and a pressure chamber formed between a back surface of the urging piston and a front surface of the input piston; wherein a first pressure receiving area of the sliding member exposed to the reaction chamber is set smaller than a second pressure receiving area of the urging piston exposed to the pressure chamber, and the second pressure receiving area is set smaller than a third pressure receiving area of the input piston exposed to the pressure chamber. The ratio of the pressure receiving area of the urging piston, exposed to the pressure chamber to the pressure receiving area of the sliding member, exposed to the reaction chamber is greater than a ratio of the pressure receiving area of the input piston, exposed to the pressure chamber of the urging piston, exposed to the pressure chamber (i.e., A.sub.2 /A.sub.1 &gt;A.sub.3 /A.sub.2).

Fluid pressure control device

In a hydraulic braking pressure control system comprising a brake device (B.sub.FL, B.sub.FR, B.sub.RL, B.sub.RR), hydraulic pressure controller (4) for controlling the hydraulic pressure supply source (2) in accordance with the amount of operation of an operating member (1), an auxiliary hydraulic pressure generator (3) including a working piston (16, 17) operatively connected to the operating member to advance in response to operation of the operating member and being slidably received in a housing (14) with a front surface of the working piston facing a hydraulic pressure chamber (18, 19), a hydraulic pressure transmitter (134) comprising a free piston (132) slidably received in a cylinder body (133) and having opposite ends facing an input hydraulic pressure chamber (130) connected to the hydraulic pressure controller and an output hydraulic pressure chamber (131) leading to the brake device, respectively, and an on-off valve (135) interposed between the hydraulic pressure chamber (18, 19) in the auxiliary hydraulic pressure generator (3) and the brake device and adapted to be closed in response to an increase in output hydraulic pressure from the hydraulic pressure controller, there is further included valve-opening device (136) for forcedly opening the on-off valve in response to the movement of the free piston by a predetermined distance or more in a direction to reduce the volume of the output hydraulic pressure chamber. This ensures that when an abnormality such as wear of a pad or a vapor lock is produced on the side of the brake device in a condition in which the hydraulic pressure supply source is normal, a deficiency of hydraulic pressure can be compensated for, and when a leak of fluid is produced, this can be detected promptly.

Hydraulic braking pressure control system having an on-off valve

A fluid pressure control system which includes an operational reaction force generating device having a piston which includes a front surface facing a pressure chamber and is operatively connected to an operating member so as to reduce a volume of the pressure chamber in response to the operation of the operating member. The fluid pressure control system further includes a fluid pressure control valve capable of adjusting and outputting an output pressure from a fluid pressure supply source capable of outputting a constant fluid pressure in accordance with the operation amount of the operating member and a stroke accumulator connected to the pressure chamber. The stroke accumulator is of a structural arrangement such that the resilient biasing force acting on the accumulator piston by the movement of the back-up piston toward the accumulator piston with the abnormal reduction in fluid pressure in the pilot chamber connected to the fluid pressure supply source is increased more than the fluid pressure acting on the accumulator piston when the fluid pressure in the pilot chamber is normal. Thus, it is possible in the fluid pressure control system of this invention to prevent the amount in which the operating member operates from being increased more than necessary when the output fluid pressure from the fluid pressure supply source is abnormally reduced.

Fluid pressure control system with an accumulator responsive to a loss

A traction control method for a vehicle according to the present invention for generating braking forces in the brake devices for driving wheels when excessive slipping has occurred in the drive wheels involves an independent control mode for independently controlling respective braking forces of the plurality of drive-wheel brake devices and a collective control mode for collectively controlling the braking forces. These two control modes are interchangeable with each other. This enables traction control which can insure both reliable driving force and high stability.

Traction control through collective or independent wheel braking

A pressure supply system for a vehicle according to the invention incorporates a pump and an accumulator in which an output pressure of the pump is maintained within a prescribed range by controlling the on-off operation of the pump according to the inner pressure of the accumulator. By changing the prescribed range of pressure according to the actual pressure requirement, for instance according to the change in the travelling speed of the vehicle, the burden on the system is reduced. The prescribed range can be changed either by simply changing the upper and/or lower pressure limits at which the pump is deactivated and activated, respectively, or by operating the pump for a prescribed time period which is dependent on the pressure requirement after a certain reference pressure value is reached. Thus, the structure of the fluid pressure system is simplified, and the generation of unnecessary high pressure can be avoided.

Pressure supply system having means for controlling an output pressure

A hydraulic pressure control system has a hydraulic pressure control valve which includes a spool slidably received in a housing for axial sliding movement between a rear position in which it permits the communication between an output port and a release port and a front position in which it permits communication between an input port and the output port. The hydraulic pressure control system also has a reaction chamber connected to the output port for providing a hydraulic pressure for biasing the spool rearwardly, and an input pressure working chamber for providing a hydraulic pressure for biasing the spool forwardly, a differential pressure regulating valve is interposed between the output port and the reaction chamber and adapted to be opened in response to the hydraulic pressure from the output port becoming higher than the hydraulic pressure in the reaction chamber by a predetermined value therefor. At an initial stage of the beginning of application of the hydraulic pressure to the input pressure working chamber, the application of the hydraulic pressure to the reaction chamber is cut off, so that the output hydraulic pressure from the output port can be rapidly increased with the spool kept located in the front position to provide a smooth initial operation of the hydraulically operated device connected to the output port.

Hydraulic pressure control system with three port spool valve

A method for traction control of a vehicle, includes detecting a slipping tendency of a drive wheel in a driven state, and controlling the braking force of a drive wheel brake device in an increasing and decreasing manner in accordance with the degree of the detected slipping tendency, wherein a rapid increase mode of rapidly increasing the braking force of the drive wheel brake device and a slow increase mode of slowly increasing the braking force can be switched from one to the other, so that at an initial stage in increasing the braking force of the drive wheel brake device on the basis of the decision that the drive wheel is in an excessive slipping tendency, the braking force is increased in the rapid increase mode.

Method for traction control of vehicle

In a hydraulic braking pressure control system including an auxiliary hydraulic pressure generating unit capable of generating a hydraulic pressure in accordance with the braking operation of a brake pedal, and a hydraulic pressure supply source hydraulic pressure control unit interposed between a hydraulic pressure supply source and a brake device for controlling the hydraulic pressure from the hydraulic pressure supply source in accordance with the braking operation of the brake pedal, the hydraulic pressure chamber in the auxiliary hydraulic pressure generating unit is connected to the supply source hydraulic pressure control unit, so that the output hydraulic pressure therefrom is applied as a control pressure. When the hydraulic pressure from the hydraulic pressure supply source has been abnormally reduced, a braking pressure from the auxiliary hydraulic pressure generating unit is applied to the brake device in response to an opening of the on-off valve. During braking in a condition in which the hydraulic pressure from the hydraulic pressure supply source is normal, the operation of the hydraulic pressure regulating unit avoids the hydraulic pressure from the auxiliary hydraulic pressure generating unit from being applied to the brake device.

Hydraulic braking pressure control system

An apparatus for diagnosing a fault of a hydraulic pressure source, including a fluid tank, a pump for pumping up fluid from the fluid tank, an accumulator for accumulating the fluid pumped up by the pump, a pressure detector for detecting a pressure of the fluid in the accumulator and generating an output signal, a pump drive or motor responsive to the output signal for driving the pump, and an electromagnetic valve of normally closed type interposed either in a flow path between the accumulator and a hydraulic pressure instrument or in a flow path between the tank and the hydraulic pressure instrument. This apparatus comprises an excitation signal generator for generating an excitation signal which excites the electromagnetic valve for a predetermined period of time, and a control unit for determing an anomaly on the basis of the output signal from the pressure detector. If any fault exists in the hydraulic pressure source, fall and rise of the hydraulic pressure is not effected normally. The control unit determines whether the variation of the hydraulic pressure is normal or abnormal on the basis of the output signal from the pressure detector.

Fault diagnostic apparatus for a hydraulic pressure source

In a hydraulic braking pressure control system comprising an auxiliary hydraulic pressure generator connected to a brake device for generating a hydraulic pressure depending upon a braking operation by a brake pedal; a supply source; a supply source pressure control device controlling the pressure from the supply source in accordance with the braking operation by the brake pedal; pressure transmitting device interposed in a hydraulic pressure path extending from the supply source via the supply source pressure control device to the brake device arranged to permit the transmission of the hydraulic pressure output from the supply source pressure control device to the brake device when the hydraulic pressure in the supply source is normal and to cut off the flowing of a working fluid from the brake device toward the supply source when the hydraulic pressure in the supply source is abnormally reduced; and an on-off valve interposed between the auxiliary hydraulic pressure generator and the brake device, having a pilot chamber leading to an output port of the supply source pressure control device, and adapted to be closed in response to an increase in the hydraulic pressure in the pilot chamber. The on-off valve is closed by rising of the output hydraulic pressure from the supply source pressure control device prior to rising of the output hydraulic pressure from the auxiliary hydraulic pressure generator during a braking operation by the brake pedal.

Growing community of inventors

Saitama, Japan

Kazutoshi Tashima