A brake control apparatus for a vehicle employs a pressure-amplifying device (10) which reduces a quantity of brake fluid generating a first brake-fluid pressure in a first conduit (A1) connected to a master cylinder (3), and increases second brake-fluid pressure in a second conduit (A2), applied to a wheel cylinder (4,5) simultaneously with the reduction in brake-fluid quantity in the first conduit (A1). As a result, increase in the first brake-fluid pressure is suppressed even when a driver depress a brake pedal (1) and load to generate the first brake-fluid pressure is alleviated. Additionally, the pressure-amplifying device (10) applies the increased second brake-fluid pressure to the wheel cylinder (4,5). Therefore, it is possible to ensure sufficient braking force.

Brake control apparatus for a vehicle

A valve mechanism is provided in a hydraulic line which connects a master cylinder of a brake system and a brake provided for a driving wheel of a vehicle. When the slip of the driving wheel is larger than a predetermined value, the valve mechanism is selectively moved between a position where it directly applies brake fluid from the master cylinder to the brake and a position where it returns brake fluid discharged from the brake to an oil reservoir, thereby controlling the driving torque of the driving wheel to converge the slip of the driving wheels to a proper level. An oil pump is operated to return the brake fluid in the oil reservoir to the master cylinder when the valve mechanism is operated to effect the slip control. While the brake pedal is in the released state, the oil pump is kept operated during the slip control and for a predetermined time after interruption of the slip control so that the brake fluid in the oil reservoir is returned to the master cylinder substantially completely. When the brake pedal is depressed while the slip being effected, the slip control is ended and the oil pump is stopped. After the brake pedal is released, the oil pump is operated for a predetermined time.

Slip control system for vehicle

A device for transmitting torque between two rotatable, coaxial shaft members (1, 2) in a stationary housing (4) has a clutch (11, 12) engageable to counteract differential rotational speed between the shaft members. A hydraulic clutch piston (14) is arranged to engage the clutch, and a hydraulic pump arrangement (1', 18-21, 11", 14-17), driven by the speed differential between the two shaft members, creates a hydraulic pressure on the clutch piston. The hydraulic pump arrangement includes a supply piston (18) and the clutch piston. Rollers (17, 21) are rotatable with one of the shaft members (2) and engage the other of the shaft members (1) via cams (1', 11"), which are angularly offset in relation to each other, so as to impart to the pistons a reciprocating movement at the differential rotational speed between the shaft members. A hydraulic line system (25, 27, 29, 31) connects a cylinder (23) at the supply piston on one hand with the tank (24) via a check valve (26) and on the other hand--via a line (27) with a check valve (28)--with an outlet line (31) and connects a cylinder (30) at the clutch piston (14) with the outlet line.

Device for transmitting torque between two rotatable shafts

An anti-skid control method for an anti-skid control device comprising two pressure medium lines installed between the master cylinder and the return pathway of the pressure medium with an inlet valve, selector valve, and discharge valve arranged in series in each of the two pressure medium lines, a front wheel brake being connected between the inlet valve and the selector valve of each pressure medium line and a diagonally opposite rear wheel brake being connected between the same selector valve and the discharge valve of that pressure medium line, and a control circuit which controls the front and rear wheel brake pressures through the pressure medium lines. The rotational speeds of each front and rear wheel are determined. The state of traction of each front and rear wheel is judged by the control circuit. The appropriate inlet valve, selector valve, discharge valve and combination thereof are activated to control locking and slippage of each front and rear wheel. In addition, the control circuit opens the inlet valves when the selector valves open to increase the brake pressure of the rear wheels to compensate for the accompanying reduction in pressure of the front wheels.

Anti-skid control method

A vehicle brake system having a wheel brake and first and second conduits in fluid communication with the wheel brake. A master cylinder having an outlet is in fluid communication with the first conduit for supplying pressurized fluid to the first conduit. The brake system further includes an isolation valve movable between a first position, wherein fluid is permitted to flow from the master cylinder to the wheel brake via the first conduit, and a second position, wherein fluid is prevented from flowing from the master cylinder to the wheel brake via the first conduit. The isolation valve is preferably a pilot-operated valve movable between the first and second positions by a pressure differential between the outlet of the master cylinder and the pressure in the second conduit between the boost valve and the wheel brake. A source of pressurized fluid is in fluid communication with the wheel brake via the second conduit. A boost valve regulates the flow of fluid through the second conduit from the source of pressurized fluid to the wheel brake and is adapted to receive pressurized fluid from the first conduit for controlling the operation of the boost valve.

Brake system having a pilot operated boost valve

In a hydraulic braking pressure control system comprising an auxiliary hydraulic pressure generator connected to a brake device for generating a hydraulic pressure depending upon a braking operation by a brake pedal; a supply source; a supply source pressure control device controlling the pressure from the supply source in accordance with the braking operation by the brake pedal; pressure transmitting device interposed in a hydraulic pressure path extending from the supply source via the supply source pressure control device to the brake device arranged to permit the transmission of the hydraulic pressure output from the supply source pressure control device to the brake device when the hydraulic pressure in the supply source is normal and to cut off the flowing of a working fluid from the brake device toward the supply source when the hydraulic pressure in the supply source is abnormally reduced; and an on-off valve interposed between the auxiliary hydraulic pressure generator and the brake device, having a pilot chamber leading to an output port of the supply source pressure control device, and adapted to be closed in response to an increase in the hydraulic pressure in the pilot chamber. The on-off valve is closed by rising of the output hydraulic pressure from the supply source pressure control device prior to rising of the output hydraulic pressure from the auxiliary hydraulic pressure generator during a braking operation by the brake pedal.

Hydraulic braking pressure control system

A method for traction control of a vehicle, includes detecting a slipping tendency of a drive wheel in a driven state, and controlling the braking force of a drive wheel brake device in an increasing and decreasing manner in accordance with the degree of the detected slipping tendency, wherein a rapid increase mode of rapidly increasing the braking force of the drive wheel brake device and a slow increase mode of slowly increasing the braking force can be switched from one to the other, so that at an initial stage in increasing the braking force of the drive wheel brake device on the basis of the decision that the drive wheel is in an excessive slipping tendency, the braking force is increased in the rapid increase mode.

Method for traction control of vehicle

A hydraulic pressure control system has a hydraulic pressure control valve (4,4′,4˝) which includes a spool (22,102) slidably received in a housing (21,101) for axial sliding movement between a rear position in which it permits the communication between an output port (29,115) and a release port (30,113) and a front position in which it permits the communication between the input port (28,114) and an output port (29,115). The hydraulic pressure control system also has a reaction chamber (32,119) connected to the output port (29,115) for providing a hydraulic pressure for biasing the spool (22,102) rearwardly, and an input pressure working chamber (34,35;118) for providing a hydraulic pressure for biasing the spool (22,102) forwardly, a differential pressure regulating valve (45,106,130) is interposed between the output port (29,115) and the reaction chamber (32,119) and adapted to be opened in response to the hydraulic pressure from the output port (29,115) becoming higher than the hydraulic pressure in the reaction chamber (32,119) by a predetermined value or more. At an initial stage of the beginning of application of the hydraulic pressure to the input pressure working chamber (34,35;118), the application of the hydraulic pressure to the reaction chamber (32,119) is cut off, so that the output hydraulic pressure from the output port (29,115) can be suddenly increased with the spool (22,102) kept located in the front position to provide a smooth initial operation of the hydraulically operated device (B LF ,B FR ,B LR ,B RR ) connected to the output port (29,115).

Jiro C

Papers

Hydraulic braking pressure control system

Method for traction control of vehicle

Hydraulic pressure control system