摘要:
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.
摘要:
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. Consequently, the lack of braking force caused by the delay of timing for decreasing the hydraulic braking pressure due to an erroneous detection of a locking condition of the road wheel on a rough road is effectively prevented.
摘要:
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. The assisting device further assists the flow control device to adequately effect the second mode of operation at least while the valve device is in the pressure-increase position during the anti-lock operation of the valve decive.
摘要:
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. The flow restrictor device may consist of two pilot-operated variable flow restrictor valves which may be disposed in the high-pressure and wheel-cylinder hydraulic systems, respectively, or both disposed in one of these two systems.
摘要:
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.
摘要:
An actuator is disclosed for use in an anti-skid brake system for wheeled vehicles. A first valve is disposed in a pressure line to selectively divide the pressure line into two separate lines. Also included is an electric motor, a pump driven by the electric motor, an accumulator adapted to accumulate fluid pressure generated by the pump, a control piston reciprocating under the fluid pressure to open and close the first valve, a second valve adapted to supply the fluid pressure to the control piston upon normal rolling of wheels so as to move the control piston to a non-operative position while excluding the fluid pressure from the control piston when the wheels are likely to lock up, and a third valve having first and second valves and controlling the fluid pressure to be supplied to a hydraulic chamber in response to depression and release of a brake pedal. In this arrangement, a relief valve is provided in a seat member of the first valve so that when the fluid pressure exceeds a predetermined upper limit, it is opened to introduce hydraulic fluid to a drain line through the second valve.
摘要:
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 the cylinders includes a changeover valve disposed in the primary 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 point of the primary passage between the master cylinder and the changeover valve, via a check valve. The anti-skid apparatus further includes a cut-off valve disposed in the primary passage between the master cylinder and the point where the pumped fluid is returned, and a regulator valve disposed in a recirculation passage for recirculating the pumped fluid to the reservoir. The cut-off valve normally allows a flow of the fluid and inhibits the flow of the fluid when the hydraulic pressure from the master cylinder exceeds the pressure from the wheel brake cylinder by at least a predetermined value. The regulator regulates the pressure of the pumped fluid at a value higher than the pressure from the wheel brake cylinder by a predetermined value.
摘要:
A brake fluid pressure control valve assembly includes a body having a single cylinder bore communicating inlet and outlet ports connected to a brake master cylinder and wheel brake cylinder, respectively. The cylinder bore accommodates the components of two separate valves, namely first, second and third seat members and first and second valve elements brought into and out of contact with seat surfaces of these seat members, as well as a spring interposed between the two valve bodies, a pressure reducing piston and a by-pass piston. First and second passageways arranged in parallel each interconnect the inlet and outlet ports through two serially arranged valve cavities in the cylinder bore and are opened and closed in a prescribed manner by the two valves in cooperation with the spring and pistons. The third seat member has seal rings fitted in first and second annular grooves formed in its outer periphery for providing a seal between the outer periphery of the third seat member and wall surfaces of axially extending bores in the first and second seat members. The diameter of first and second end portions outwardly of the first and second annular grooves, respectively, of the third seat member is such that these end portions will not contact the wall surfaces of the axially extending bores of the first and second seat members, respectively.
摘要:
A hydraulic braking system having a master cylinder, a brake cylinder, a primary passage connecting the master and brake cylinder, a solenoid valve for selective communication of the brake cylinder with the master cylinder or with a reservoir, a pump for returning a brake fluid to the master cylinder, a shut-off valve disposed in the primary passage to prevent a flow of the fluid from the pump toward the master cylinder when the pump side pressure is higher than the master cylinder side pressure, an accumulator having a piston movable to define a variable volume chamber for storing the fluid under pressure, the braking system comprising a check valve in the primary passage between the master cylinder and the shut-off valve to inhibit a fluid flow therethrough in one direction from the master cylinder toward the shut-off valve, and further comprising a mechanism disposed between the accumulator and the check valve to hold a valve member of the check valve away from its seat to allow the fluid flow in the above-identified one direction while the accumulator piston is in its advanced position in which the volume of the accumulator chamber is minimum, the mechanism permitting the check valve member to be seated on the seat after the accumulator piston has been moved away from the advanced position.
摘要:
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. The antilock brake control is performed by controlling communication between said wheel cylinder and each of the master cylinder, the outlet port of the pump and the supplementary reservoir and actuating the pump. The inlet control valve is opened when both the brake assist control and the antilock brake control are performed concurrently.