Abstract: A brake force control apparatus which can always accurately generate a brake force confirming to a driver's intention is provided. The brake force control apparatus performs brake assist control for supplying an increased brake fluid pressure which is greater than that generated in a regular brake operation to a wheel cylinder of a vehicle when an emergency brake operation is performed by a driver. A deceleration of the vehicle is detected. Additionally, a difference between a target deceleration which is to be generated during execution of the brake assist control and the deceleration is detected. A brake fluid pressure which is supplied to the wheel cylinder during execution of the brake assist control is controlled based on the difference.

Abstract: A brake force control apparatus having a pump for pumping up brake fluid from a fluid pressure passage connecting a master cylinder and a wheel cylinder is provided which can accurately detect an amount of brake operation intended by a driver during execution of a brake assist control. The brake assist control is achieved by supplying the brake fluid delivered by the pump to the wheel cylinder when an emergency brake operation is performed by a driver. The brake force control apparatus has a control signal generator and a fluid pressure controller. The control signal generator generates a control signal by compensating a decrease generated in the output signal when the pump pumps up the brake fluid from the fluid pressure passage. The fluid pressure controller performs the brake assist control by using the control signal.

Abstract: A brake force control apparatus performs both a brake assist control and an antilock brake control without interference therebetween. A master cylinder generates a brake fluid pressure corresponding to a magnitude of a brake operation. A pump has an inlet port and an outlet port, the inlet port being communicable with the master cylinder. An inlet control valve controls communication between the master cylinder and the inlet port of the pump. A wheel cylinder is communicable with each of the master cylinder and the outlet port of the pump. A supplementary reservoir is communicable with each of the wheel cylinder and the inlet port of the pump. The brake assist control is performed, when the emergency brake operation is performed by the driver, by opening the inlet control valve and actuating the pump.

Abstract: An anti-skid apparatus for installation in a vehicle braking system includes an electrically operated actuator arranged to control hydraulic brake pressure applied to each wheel brake cylinder of road wheels of the vehicle and an electronic control device for applying an electric control signal to the actuator in response to electric signals indicative of each rotational speed of the road wheels so that the actuator is operated to decrease or increase the brake pressure when the rotational speed of the road wheels in braking operation becomes lower than a reference speed the value of which is defined on a basis of a travel, speed of the vehicle.

Abstract: The anti-skid control system is capable of performing highly reliable anti-skid control through its accurate estimation of the vehicle speed and proper compensatory control even when sharp braking occurs or in the brake fluid pressure control on road surfaces with a low coefficient of friction likely to cause considerable fluctuations in wheel acceleration. The anti-skid control system is provided with a fluid pressure generating device, a fluid pressure controlling device, a wheel velocity detecting device, a standard speed setting device, a fluid pressure controlling mode setting device which sets either the pressure decrease mode or the pressure hold mode when the wheel velocity declines to a level lower than the standard speed and sets the pressure increase mode when the wheel velocity is equal to or higher than the standard speed.

Abstract: The anti-skid control system is constructed with a brake fluid pressure source for generating brake fluid pressure at high and low levers, a switching valve feeding either high pressure or low pressure to the wheel cylinders, a wheel velocity detecting device sensing the driving wheel rotating speed, an acceleration detecting device detecting the vehicle acceleration and a first arithmetic operation device for finding the estimated vehicle speed and the wheel rotating acceleration based on the wheel velocity detected by the wheel velocity detecting device and the vehicle body acceleration detected by the acceleration detecting device. A brake fluid pressure controlling device is provided for increasing, decreasing or maintaining the brake fluid pressure in the wheel cylinders, controlling the switching valve on the basis of wheel velocity, estimated vehicle speed, and wheel rotating acceleration.

Abstract: An anti-skid control system for an automotive vehicle is provided with an actuator which is disposed in a hydraulic circuit between a pressure generator and a wheel brake cylinder. The actuator is arranged to control the hydraulic braking pressure applied to the wheel brake cylinder. In response to a wheel speed detected by a wheel speed detector, it is determined in an electronic control unit whether a condition for decreasing the braking pressure is effected. When this condition is effected, the decrease mode is provided in the control unit. When a predetermined period of time lapses after the decrease mode is initiated, the decrease mode is turned to a pressure control mode for applying the braking pressure to prevent the road wheel from being locked. When the condition is not effected during the predetermined period of time after the decrease mode is initiated, the decrease mode is turned to a direct supply mode for directly communicating the pressure generator with the wheel brake cylinder.

Abstract: The anti-skid control system is provided with wheel velocity sensors only for the driving wheels and yet is capable of performing the anti-skid control through its accurate estimation of the vehicle speed and proper compensatory control even when sharp braking occurs immediately upon the release of the accelerator after the occurrence of acceleration slip. The anti-skid control system is capable of starting the anti-skid control with certainty even when the braking operation is not detected because of a failure in the operation of the brake switch. The system is provided with a fluid pressure generating device, a fluid pressure controlling device, a brake operation detecting device, an acceleration detecting device, a wheel velocity detecting device, a braking force controlling device, a brake force correcting device and an acceleration slip detecting device.

Abstract: An anti-lock brake system is arranged such that the recirculation line from the overflow reservoir feeds into one of the brake lines downstream of the lines dividing point. A constriction, which may take the form of a simple nozzle is positioned between the recirculation line junction and the brake line dividing point for reducing the coupling of pressure fluctuations between the brake lines when the anti-lock system is actuated. With this arrangement, even upon the occurrence of sharp pressure fluctuations in one of the brake lines due to actuation of the anti-lock function, the pressure of the other brake line is not affected thereby allowing proper controlled braking in each wheel.

Abstract: An anti-lock brake system for a wheel wherein a fluid pressure is applied to a wheel cylinder, through a solenoid-operated valve device and a flow control device. Upon detection of locking of the wheel, the valve device is brought into an anti-lock state in which the valve device is alternately placed in its pressure-increase and pressure-decrease positions. The flow control device is normally placed in a first mode for a sufficient flow of the fluid into the wheel cylinder, and is operated in a second mode with the valve device placed in the anti-lock state. In the second mode, the flow control device decreases the rate of fluid flow to the wheel cylinder, with an increase in a difference between the power source pressure and the wheel cylinder pressure. An assisting device is provided for enabling the flow control device to adequaely effect the first mode of operation for at least a period between commencement of brake application and commencement of anti-lock operation of the valve device.

Abstract: The invention is directed to an arrangement for monitoring a road condition which determines the coefficient of friction of the road surface on the basis of a signal corresponding to an acceleration of a vehicle detected by an acceleration sensor. The signal is converted into one of at least two predetermined values by conversion means in response to a magnitude of the acceleration every cycle of a predetermined time period. The converted value is summed up by summing means by a predetermined number of consecutive cycles to provide a total value in the last cycle thereof which is stored in memory means. Then, in determination means, one of at least two standard values is selected in response to the condition of increase or decrease of the total value in the present cycle provided by the summing means as compared with the total value in the previous cycle stored in the memory means.

Abstract: The anti-skid control system is provided with wheel velocity sensors only for the driving wheels and is capable of performing the anti-skid control through its accurate estimation of the vehicle speed and proper compensatory control even when sharp braking occurs immediately upon the release of the accelerator after the occurrence of acceleration slip. The anti-skid control system is capable of starting the anti-skid control with certainty even when the braking operation is not detected because of a failure in the operation of the brake switch. The system is provided with a fluid pressure generating device, a fluid pressure controlling device, a brake operation detecting device, an acceleration detecting device, a wheel velocity detecting device, a braking force controlling device, a first estimated vehicle speed setting device and a second estimated vehicle speed setting device.

Abstract: A braking device having a high-pressure hydraulic system including a hydraulic pressure source, a wheel-cylinder hydraulic system including a wheel cylinder for applying brake to a vehicle wheel, a low-pressure hydraulic system including a reservoir, a solenoid-operated directional control valve device for fluid communication of the wheel-cylinder hydraulic system selectively with the high-pressure hydraulic system or the low-pressure hydraulic system, an electric control device connected to the directional control valve device to control the wheel cylinder pressure, and a variable flow restrictor device disposed in the high-pressure hydraulic system or the wheel-cylinder hydraulic system, for decreasing a rate of flow of the fluid through the high-pressure or wheel-cylinder hydraulic system, with an increase in a pressure difference between the high-pressure and wheel-cylinder hydraulic systems, and with an increase in a pressure in the wheel-cylinder hydraulic system.

Abstract: An anti-skid apparatus for installation in a vehicle braking system having a master cylinder, a wheel brake cylinder and a primary fluid passage connecting these cylinders includes a changeover valve disposed in the primary fluid passage to selectively communicate the wheel brake cylinder with the master cylinder or with a reservoir, and a fluid pump for pumping a brake fluid from the reservoir and returning it to a portion of the primary fluid passage between the master cylinder and the changeover valve. The anti-skid apparatus further includes a control valve disposed in that portion of the primary fluid passage. The control valve comprises a piston slidably disposed in a housing, and a valve member slidably disposed in the piston and seatable on a valve seat with a cutout formed thereon. The control valve allows a flow of the brake fluid from the master cylinder and/or the fluid pump to the wheel brake cylinder through the changeover valve without restriction in normal braking operation.

Abstract: An antiskid control system is disclosed in which a single solenoid-operated switching valve connects a single wheel brake selectively to a high pressure or low pressure from a source of brake pressure. After the decompression of a wheel brake pressure, a repetitive intensifying operation is executed with a period of 40 msec in which an intensifying and a decompressing operation take place alternately. During the repetitive intensifying operation, the duty cycle for the intensifying operation is increased at a given rate. A flash intensification is executed immediately before the repetitive intensification. An initial value of the duty cycle for the repetitive intensification which occurs after the decompression of a second and a subsequent pass is chosen in proportion to the time duration of the previous repetitive intensifying operation and in inverse proportion to the immediately preceding decompressing interval.

Abstract: A gas leakage detecting device for detecting leakage of a precharged gas from a gas-type accumulator which is connected to a hydraulic pump and which stores a pressurized hydraulic fluid delivered from the pump. The pump is turned on to initiate accumulation of the pressurized fluid in the accumulator when a pressure of the pressurized fluid falls below a lower limit, and turned off when the pressure rises to an upper limit. The detecting device detects an occurrence of leakage of the precharged gas from the accumulator, where a time duration between moments of activation and de-activation of the pump is less than a predetermined reference value.

Abstract: An actuator for a wheel anti-lock system, which comprises a first conduit connected to a brake master cylinder and a second conduit connected to a brake wheel cylinder. To the second conduit, there is connected a reservoir for reserving a predetermined amount of working liquid. Between the first conduit and the second conduit, there is interposed a feed change-over valve for opening or closing the communication between them. Between the second conduit and the reservoir, there is interposed a release change-over valve for opening or closing the communication between them. In the first conduit, there is disposed a normally open cut valve for closing the first conduit when in a skid control. To the first conduit, there is connected a pressure transducer in parallel with the cut valve.

Abstract: An antiskid apparatus for an automotive vehicle including a cut-off valve having an inlet side to which a master cylinder is connected and an outlet side to which a wheel cylinder is connected for cutting off a supply of pressurized oil from the master cylinder to the wheel cylinder when an antiskid operation is performed, and a pump connected between the cut-off valve and wheel cylinder for supplying pressurized oil to the wheel cylinder when an antiskid operation is performed. The master cylinder and wheel cylinder being brought into slight communication via a microgroove in the spool of the cut-off valve when the spool is at a closed position. Pedal shock at antiskid operation is alleviated.

Abstract: An antiskid apparatus including a changeover valve disposed in a line connecting a master cylinder and a wheel brake, the changeover valve being changed over between a first mode for cutting off the wheel brake from the master cylinder and connecting the wheel brake to a reservoir, and a second mode for alternately connecting the wheel brake to a pump and the reservoir when an antiskid operation is performed, a pressure increase control valve connected between the pump and changeover valve with wheel brake pressure serving as a control signal pressure, and a pressure decrease control valve connected between the wheel brake and reservoir with wheel brake pressure serving as a control signal pressure. The pressure increase control valve decreases an amount of pressurized oil flow from the pump to the wheel brake when wheel brake pressure decreases and increases the amount of pressurized oil flow from the pump when wheel brake pressure increases.

Abstract: A hydraulic pump assembly for use in combination with an accumulator comprises a pump housing provided with an inlet port for connection to a fluid reservoir and an outlet port for connection to the accumulator, a single cam shaft rotatably mounted within the housing to be driven by an electric motor, a first plunger pump assembly of large displacement capacity including a first plunger axially slidably disposed within the housing perpendicularly to the cam shaft to be reciprocated by engagement with the cam shaft, and a second plunger pump assembly of small displacement capacity including a second plunger axially slidably disposed within the housing perpendicularly to the cam shaft to be reciprocated by engagement with the cam shaft and opposed to the first plunger. An exhaust check valve of the first plunger pump assembly is interconnected to a suction check valve of the second plunger pump assembly.