Abstract: In a hydraulic braking pressure control system for a rear wheel brake wherein a control piston normally works to provide a hydraulic braking pressure control by cooperation with a cut-off valve interposed between an input chamber leading to a master cylinder and an output chamber leading to a wheel cylinder of the brake, the cut-off valve has a valve seat piston whose pressure-receiving area facing the output chamber is larger than the pressure-receiving area facing the output chamber. This ensures that opening and closing of the cut-off valve can be repeated in accordance with the output pressure from the master cylinder, so that the output pressure from the master cylinder can be reduced and applied to the brake wheel cylinder.

Abstract: An electromagnetic valve device having two electromagnetic valves comprises a solenoid unit having a unit construction in the form of a hollow cylinder and having a pair of solenoids, and a valve unit having a pair of valve mechanisms and having a unit construction in the form of a substantially solid cylinder. The solenoid unit has a pair of coil bobbins, and a pair of caps accommodating said coil bobbins. The valve unit is fitted through a central through hole of the solenoid unit and thus mounted therein. The coil bobbins are fixed to a yoke interposed therebetween and thus joined together.

Abstract: The present invention relates to a method for estimating vehicle speeds independently on front and rear wheels of a four-wheel motor vehicle on the basis of front wheel speeds and rear wheel speeds, for use as a basis for determining slip rates for front and rear wheels. According to the first method of the invention, a reference wheel speed determined by the vehicle speed as estimated from the left and right wheel speeds cannot be unnecessarily increased during turning of the vehicle. According to the second and third methods of the invention, the estimated vehicle speed largely does not deviate from the actual vehicle speed in the event of a phase difference of variants produced between the left and right wheels due to an anti-lock control during the turning of the vehicle.

Abstract: A hydraulic braking pressure control system which includes a sleeve slidably received in a housing with opposite ends facing an output chamber connected to a brake device, and a pilot chamber connected to a control hydraulic pressure source. A control piston is slidably received in the sleeve, with one end of the control piston facing the output chamber and the other end facing a control chamber connected to the control hydraulic pressure source through a lock valve which is adapted to be closed in response to the movement of the sleeve, in a direction to increase the volume of the output chamber. A cut-off valve located between an input chamber leading to a master cylinder and the output chamber includes a valve member having a maximum amount of movement in a seating direction which is regulated to a position of the valve member spaced apart from a valve seat when a valve seat member follows movement of the sleeve in a direction to reduce the volume of the pilot chamber to the maximum amount.

Abstract: The present invention is a method for estimating the speed of a vehicle with antilock brake devices by obtaining a vehicle speed as a reference value for determining a slip ratio of a wheel based upon a wheel speed, an acceleration and a deceleration. At least the deceleration is based upon a differentiated value of a highest wheel speed from all wheels. In a vehicle in which the drive wheels are rigidly coupled, at least the deceleration is based upon a differentiated value of a highest value of the lowest wheel speed of the drive wheels and the wheel speeds of the driven wheels.

Abstract: In a method of anti-lock brake control, in which when the wheel is about to become locked, a control valve is capable of controlling a braking pressure for a brake device irrespective of a braking operation. The control valve is operated to reduce the braking pressure of the brake device in order to reduce a braking force, thereby preventing the wheel from becoming locked. When the braking pressure is to be recovered, the control valve is operated to intermittently increase the braking pressure of the brake device for a given time in order to moderate the increasing of the braking force. The control of the intermittent increasing of the braking pressure is stopped when the completion of the braking operation has been detected in the course of intermittently increasing the braking pressure in recovering the braking pressure. This avoids the wasteful operation of the control valve to prevent the generation of any unwanted operational noise and a wasteful consumption of electric power.