Abstract: A hydraulic power booster having a lever device disposed in operative association with a reaction piston, a power piston and a valve spool, for moving the valve spool in one of opposite axial directions thereof for applying a pressure of a pressure source into a power chamber to advance the power piston, in response to a relative movement between the reaction and power pistons. The booster is provided with a backup actuator including a cylinder, and a valve drive piston which slidably engages the cylinder. The cylinder and the valve drive piston cooperate with each other to define a first fluid chamber communicating with the power chamber, and a second fluid chamber communicating with a pressure chamber in which a pressure is generated according to an advancing force of the power piston.

Abstract: A hydraulic braking system for an automotive vehicle is provided with a power source for generating a hydraulic power pressure, a master cylinder, a hydraulic booster for introducing the hydraulic power pressure and actuating the master cylinder in response to operation of a brake operating member, a wheel brake cylinder for braking a road wheel, a changeover valve, and anti-skid control device for actuating the changeover valve into a position where the wheel brake cylinder is communicated with the booster and regulating the hydraulic pressure in the wheel brake cylinder on the basis of the hydraulic power pressure in the booster when the road wheel is in a slip condition.

Abstract: A tandem master brake cylinder has first and second pistons, each piston associated with a fluid chamber and a pressure chamber. The pistons are displaced in response to actuation of a brake pedal. A hydraulic booster is coupled to a power source and is operable to enhance the piston movement and for conducting pressurized fluid to a second of the fluid chambers associated with a second piston to displace that piston in a manner reducing the volume of the pressure chamber associated with the first piston. In the event that a negative pressure is communicated with the second fluid chamber, e.g. by a loss of pressurized fluid from the power source, brake fluid is supplied through a one-way check valve to the second fluid chamber to prevent the negative pressure from reversing the motion of the second piston.

Abstract: A hydraulic braking system includes a tandem master cylinder having a bore with an opening and a closed wall at opposite ends thereof which formed in a housing, a first piston slidably fitted in the bore so as to define a first pressure chamber and a first fluid chamber therein and operatively connected to a brake pedal, a second piston slidably fitted in the bore so as to define a second fluid chamber adjacent to the first pressure chamber and a second pressure chamber and operatively connected to the first piston. A normally open valve communicates with each piston so as to close passages formed in the each pistons and communication between each fluid chambers and each pressure chambers, respectively, when each piston is moved in response to the depression of the brake pedal. A power source generates a hydraulic power pressure.

Abstract: A hydraulic braking system for an automotive vehicle having a power source for generating a hydraulic power pressure, a reservoir, a master cylinder, a hydraulic booster for actuating the master cylinder in response to depression of a brake pedal and a plurality of wheel brake cylinders for braking respective road wheels, which are divided into a first group of wheel brake cylinders communicating with the master cylinder and a second group of wheel brake cylinders communicating with the hydraulic booster. An auxiliary cylinder is disposed between the hydraulic booster and the second group of wheel brake cylinders. The auxiliary cylinder includes a cylinder body having a cylinder bore defined therein and a piston axially slidably disposed within the cylinder bore. The piston forms within the cylinder bore a first chamber and a second chamber, and blocks a fluid communication therebetween.

Abstract: A hydraulic braking system for an automotive vehicle having a power source for generating a hydraulic power pressure, a reservoir, a master cylinder, a hydraulic booster for actuating the master cylinder in response to depression of a brake pedal and a plurality of wheel brake cylinders for braking respective road wheels, which are divided into a first group of wheel brake cylinders communicating with the master cylinder and a second group of wheel brake cylinders communicating with the hydraulic booster. An auxiliary cylinder is disposed between the master cylinder and the first group of wheel brake cylinders to which a hydraulic braking pressure from the master cylinder is directly applied in its inoperative condition, and it increases the hydraulic braking pressure in response to depression of the brake pedal in its operative condition which is made when the hydraulic power pressure, for example, is less than the hydraulic braking pressure by a predetermined difference.

Abstract: A hydraulic braking system having an auxiliary piston disposed between an input piston and a presser piston, so as to define a first power chamber between the auxiliary and presser pistons, and a second power chamber between the input and auxiliary pistons. The presser piston cooperates with a housing to define a pressure chamber connected to a first braking arrangement. The first power chamber is connected to a second braking arrangement and supplied with a power pressure from an external hydraulic source through a control valve and the second power chamber. The system includes a connecting mechanism connecting the auxiliary and presser pistons such that the two pistons are normally placed in a spaced-apart state but are abuttable on each other.

Abstract: A pair of spaced apart large-diameter and small-diameter lands between which a fluid chamber is defined are formed on a second piston in a tandem cylinder to which an anti-skid device is added. Booster pressure is applied to the fluid chamber to act on the large-diameter land in a manner fluidly locking the second piston against movement despite a reduction in pressure in the first and second pressure chambers during operation of the anti-skid device. As a result, the movement of the brake pedal in the normal direction of depression is prevented when the anti-skid devices operates.

Abstract: A tandem master cylinder with a booster used for a hydraulic actuator such as an automotive brake system. The master cylinder has a first and a second independently movable presser piston disposed in tandem in a first housing such that the presser pistons and the first housing define a first and a second pressure chamber. The booster has a first power piston advanced by a fluid pressure in a first power chamber formed in a second housing, to advance the first presser piston. The booster has a valve operable due to a relative movement between the first power piston, and an operating member for operating said booster, whereby the fluid pressure in the first power chamber is controlled according to an operating force applied to the operating member.

Abstract: A braking control apparatus for use in a motor vehicle having at least one wheel comprising a master cylinder for generating a hydraulic pressure in response to a braking operation of a vehicle driver, an accumulator for accumulating a hydraulic pressure and at least one wheel braking cylinder for braking the wheel in accordance with a hydraulic pressure supplied thereinto. A passage system is provided so that the wheel braking cylinder is communicated therethrough with the master cylinder and the accumulator. In the passage system are provided first and second change-over valves for cutting off the pressure from the master cylinder, cutting off the pressure from the accumulator and a third control valve disposed between the wheel braking cylinder and the master cylinder or the accumulator for establishing and cutting off the communication therebetween.

Abstract: A vehicle anti-lock braking system having a master cylinder operated upon operation of a brake operating member, a wheel cylinder activated by a pressure produced by the master cylinder, and an anti-lock control device which includes a slip ratio detector for detecting a slip ratio of a drive wheel of the vehicle, and a pressure regulating device for controlling a pressure in the wheel cylinder, so as to maintain the slip ratio in an optimum range. The system also has a traction control device including a traction control power source, and a communication switching device for selective communication of the pressure regulating device with the traction control power source or the master cylinder.

Abstract: A hydraulic brake system includes a master cylinder for generating a brake fluid pressure in response to a brake pedal, a power fluid source for generating a power fluid pressure by increasing a brake fluid to a predetermined pressure. A dynamic fluid pressure control apparatus supplies the brake fluid pressure to regulate the power fluid pressure from the power fluid pressure source in response to the brake pedal. A plurality of wheel cylinders of each wheel for the vehicle are fluidically communicated with a dynamic fluid pressure control apparatus and the master cylinder via a fluid passage separated into plural control systems.

Abstract: A hydraulic booster equipped with an emergency accumulator, wherein reaction and power pistons are slidably fitted in a housing such that the two pistons define a power chamber therebetween. The booster includes a control valve having a normally closed power chamber passage formed therethrough so as to communicate with the power chamber, and a normally open passage connecting a pump and a reservoir. The valve is operated in response to an operation of the reaction piston, so as to restrict a fluid flow through the normally open passage from the pump toward the reservoir, thereby raising a pressure of the fluid delivered from the pump, and open the power chamber passage to apply the raised pressure to the power chamber. A pressure reducing device is provided in the power chamber passage, for reducing a fluid pressure in the power chamber passage and applying the reduced pressure to the power chamber, at least while a rate of fluid flow through the power chamber passage is higher than a preset limit.

Abstract: Disclosed is an anti-skid control system incorporated in the hydraulic pressure braking apparatus of a motor vehicle including a wheel braking cylinder responsive to a hydraulic pressure developed by a master cylinder for braking a wheel of the vehicle. The anti-skid control system comprises a hydraulic pressure supplying device and a directional control valve provided between the wheel braking cylinder and the hydraulic pressure supplying device. The directional control valve is actuated to shut off the communication therebetween and the actuation thereof is controlled in accordance with a duty cycle, which is in turn updated in accordance with the difference between a wheel speed and a target wheel speed so that the slip ratio of the wheel becomes equal to a target slip ratio.

Abstract: An accumulator has a piston axially slidably disposed in a cylinder mounted in a casing, the cylinder and the piston jointly defining a reservoir communicating with an inlet/outlet port in the casing. A piston rod axially movably disposed in the casing has an end slidably fitted in the cylindrical hole of the piston. The piston rod is normally urged by a spring to force the piston into the reservoir. The accumulator also includes a switch mechanism for detecting the position of the piston in the cylinder. The switch mechanism may comprise a reed switch, a light-sensitive switch, a pressure-sensitive switch, or a pushbutton switch.

Abstract: A wheel slip control system for independently executing an anti-skid control and a traction control. The system includes a microcomputer, a first capacity control valve for anti-skid control, a selector valve, and a second capacity control valve for traction control. These values are connected in series between a master cylinder and a break cylinder. Such valves prevent brake fluid from over-charging a reservoir even in the course of switching from anti-skid control to traction control or vice versa, so that the brake pressure is properly reduced without consideration of capacity of the reservoir.

Abstract: In this portless type master cylinder device, a cylinder bore is formed in a body thereof, and a piston member is fitted in the cylinder bore and is slidably movable from an initial axial position therein and defines a pressure chamber on its one side and a reservoir chamber on its other side in cooperation with the cylinder bore. An intake valve communicates between the cylinder chamber and the reservoir chamber, and is opened when the piston member is in its initial axial position while it is closed when the piston member moves through more than a determinate relatively small axial distance from its initial axial position. Intermediately along the fluid flow path between the intake valve and the reservoir chamber, there is provided a means for presenting a relatively high flow resistance to flow of fluid in the direction from the intake valve to the reservoir chamber.

Abstract: Disclosed is a hydraulic pressure control system for a motor vehicle which may be employed for anti-skid control. The control system comprises a wheel braking device for providing the brake for a wheel of the vehicle under hydraulic pressure, a braking pressure switching device for performing the switching operation at least between the increasing and decreasing of the hydraulic pressure applied to the wheel braking device, and a hydraulic pressure control unit for supplying a control signal to the braking pressure switching device at a predetermined interval so that the hydraulic pressure value to be applied to the wheel braking device becomes equal to a target hydraulic pressure value. The control unit compares the target hydraulic pressure value with first and second reference values which are obtained on the basis of an estimated hydraulic pressure value estimated to apply the wheel braking device and producing the control signal in accordance with the results of the comparison.

Abstract: In the vacuum boosting system for the brake of a vehicle wherein the boosting vacuum is supplied from the intake manifold of the engine and also, as an assistance thereto, from a vacuum pump which is to be occasionally operated when the intake vacuum of the engine is insufficient to boost the brake, the operation of the vacuum pump is controlled in two alternative modes. In the first mode, when the vehicle is running at a relatively high speed with the transmission being shifted to a relatively high speed stage, the vacuum pump is switched on when the brake boosting vacuum has dropped below a first relatively high threshold value to be operated for a first relatively short period so as to recover the vacuum.

Abstract: A pressure generator having a high-pressure accumulator connected to a high-pressure pump by a high-pressure conduit via a first check valve, to store a high-pressure fluid from the high-pressure pump, a charging accumulator connected to the high-pressure pump, for storing a low-pressure fluid and supplying the high-pressure pump with the low-pressure fluid, and a charging pump for supplying the charging accumulator with the low-pressure fluid. The charging accumulator includes leak means for permitting the low-pressure fluid to leak at a low rate. The high-pressure conduit is connected to a storage chamber of the charging accumulator by a communication passage in which is disposed a second check valve for preventing a flow of the fluid from the high-pressure conduit toward the charging accumulator.