Abstract: A solenoid controlled valve comprises a spool. One end side of the spool is slidably inserted into a first fluid chamber of a sleeve in a fluid tight condition. The other end of the spool is loosely inserted into a second fluid chamber. The spool with a stationary orifice is provided in an inlet path extending in axial direction. A spring for urging the spool and a movable core fixed to the spool, and a coil are provided. When electric current is supplied to the coil, the movable core is attracted against the spring force and the spool moves opposite to the urging direction of the spring, so that the external peripheral face of the spool closes the first port and the second port.

Abstract: An anti-skid control apparatus includes a fluid pressure control valve positioned between a master cylinder and a wheel cylinder of each wheel. The fluid pressure control valve controls the wheel pressure cylinder. A reservoir is provided for temporarily storing brake fluid expelled from the wheel cylinder during an anti-skid control. A pumpless fluid pressure control device is also provided for circulating brake fluid stored in the reservoir back to a master cylinder without using a pump. A flow control valve for maintaining a constant flow of brake fluid is positioned between the master cylinder and the wheel cylinder.

Abstract: An anti-lock controller apparatus is constituted of a single microcomputer to reduce production costs and improve safety and reliability. Signals of wheel speed sensors S.sub.1 to S.sub.4 divided into two groups by an input processing circuit and are inputted to the single microcomputer. The single microcomputer executes two-system input/output processing and checks for abnormalities of the input/output signals.

Abstract: An antilock brake control device comprising: a main microprocessor which forms a judgment on antilock control on the basis of wheel speed signals inputted from wheel speed sensors so as to output control signals to an actuator of a brake fluid pressure circuit in accordance with the judgment; a drive circuit for outputting drive signals to the actuator in response to the control signals; and a monitor for monitoring the control signals of the main microprocessor; wherein when a state in which the main microprocessor outputs to the actuator at least once during a first predetermined period the control signals for commanding pressure reduction or pressure holding has lasted continuously for not less than a second predetermined period, the monitor outputs, by judging that the main microprocessor does not function properly, a control prohibition signal for prohibiting operation of the drive circuit.

Abstract: An antiskid control device which calculates an estimated fluid pressure of each of wheel cylinders under antiskid control in each control cycle so as to adjust a fluid pressure of each of the wheel cylinders on the basis of the estimated fluid pressure and behaviors of the wheels. The device includes a differential pressure detecting member which detects a difference between a fluid pressure of a master cylinder and the fluid pressure of each of the wheel cylinders so as to produce an output signal indicative of the difference between the fluid pressure of the master cylinder and the fluid pressure of each of the wheel cylinders. When the difference between the fluid pressure of the master cylinder and the fluid pressure of each of the wheel cylinders is found to be in the vicinity of zero, the estimated fluid pressure of each of the wheel cylinders is set to a predetermined value by stopping addition in calculation of the estimated fluid pressure.

Abstract: A gravitational accelerometer for use in an automotive vehicle includes a plurality of wheel speed sensors for outputting a wheel speed by measuring a rotational speed of at least one of vehicle wheels, an acceleration sensor for detecting and outputting an acceleration Am applied to the automotive vehicle, an estimated vehicle acceleration computing unit for computing and outputting an estimated vehicle acceleration Aw estimated from the wheel speed, and a correction quantity computing unit for computing variable correction quantity Ao for each calculation cycle. A horizontal road surface detection unit is provided to detect a generally horizontal road surface. A horizontal correction quantity storage stores and outputs a horizontal correction quantity AoH, which is a correction quantity with respect to the generally horizontal road surface, in response to an output from the horizontal road surface detection unit.