Robert Boschgmbh

Roland Holzmann

Karl-Heinz Willmann

Wolf-Dieter Jonner

Guenther Schmidt

Elmar Mueller

Hans-Juergen Herderich

Thomas Isella

Helmut Pueschel

Rolf Hummel

Martin Moehle

Johann Herr

Guenter Dzierzawa

Norbert Alaze

Gerhard Wetzel

Michael Friedow

Alfred Sigl

Wolfgang Bernhardt

Lothar Kirstein

Guenter Krenz

Arnold Pahl

Erika Mank

The invention relates to a hydraulic vehicle brake system with a master cylinder, with two brake circuits (I, II), with wheel brakes connected to the brake circuits (I, II), and with a wheel slip regulator device disposed between the master cylinder and the wheel brakes, which device has at least one brake pressure modulation valve device and at least one high pressure pump, and with a pump unit associated with this high pressure pump. In the automatic braking operation by means of at least one of the high pressure pumps, the pump unit is used for supplying hydraulic fluid to the high pressure pump. The pump unit has a low pressure pump in the form of a gear pump. To limit the pressure at an outlet of the low pressure pump at least one return flow conduit is provided between this outlet and an inlet, which conduit, in a manner according to the invention constitutes a throttle by which the choice of its cross section, which throttle is for controlling at least one return flow which increases with increasing pressure at the outlet and as a result achieves the pressure limiting. The hydraulic vehicle brake system can be used for cars, minibuses, and small trucks.

Hydraulic vehicle brake system with wheel slip regulator device

Vehicle hydraulic brake system

A known vehicle brake system having an anti-lock system has at least one return pump in this anti-lock system, by means of whose pumping pressure a throttle valve located between the master brake cylinder and the at least one wheel brake can be controlled via a control inlet, during an anti-lock mode, out of the normal position into a throttling position, counter to the force of an opening spring. The throttle valve serves to limit brake pressure rise speeds in the wheel brake during an anti-lock mode. It is disadvantageous that upon termination of such an anti-lock mode, the throttle valve hinders the return flow of pressure fluid out of the wheel brake to the master brake cylinder. Brake pressure reductions are therefore delayed. A throttle valve and connected in accordance with the invention has a second control inlet, which communicates with the wheel brake. The wheel brake pressure, upon termination of braking with anti-lock operation, is used as control pressure for opening the throttle valve, which as a result reaches its normal open position earlier and faster.

Hydraulic anti-lock vehicle brake system for a vehicle

A brake system equipped with an anti-lock and traction control system including first shutoff valve and a first inlet valve of a valve assembly for brake pressure modulation are disposed in a first brake line connected with a master brake cylinder and a wheel brake. Toward the wheel brake, a third return line having a first outlet valve of the first valve assembly begins at the first brake line and leads to a first high-pressure pump, which pumps fluid into the first brake line. On the intake side, the pump communicates with the master brake cylinder, through a suction line having a charging valve. For brake pressure modulation in the traction control mode, phases for pressure buildup, pressure holding and pressure reduction can be controlled with the high-pressure pump, the first shutoff valve, the charging valve and the first inlet valve, while the first outlet valve assumes its shutoff position. A first storage chamber connected to the third return line therefore remains free of pressure fluid. The hydraulic multi-circuit brake system can be used in particular in motor vehicles.

Hydraulic multi-circuit brake system in particular for motor vehicles

A hydraulic brake system having an anti-lock system (ABS) and traction control (ASR) for motor vehicles including a hydraulic unit with at least one control valve and a return pump having at least one pump element that is embodied as self-aspirating pump element and that is operative in a brake circuit, which contains at least one drive wheel. A valve assembly serves to furnish brake pressure in ASR and each valve assembly comprises a respective charging valve embodied as a 2/2-way magnet valve and an electromagnetic reversing valve. In order that a low hydraulic power requirement can be attained in traction control, only the valve assembly is triggered, and is triggered such that for pressure buildup the electromagnetic reversing valve blocks fluid flow and the charging valve is opened, while for pressure holding both valves block fluid flow, and for pressure reduction the charging valve blocks fluid flow and the electromagnetic reversing valve is opened.

Hydraulic brake system

A brake system having a master brake cylinder for producing a brake pressure controllable by a brake pedal and transmitting it to at least one brake circuit, which connects the master brake cylinder with corresponding wheel brake cylinders of the front and rear wheels. At least one shutoff valve for anti-skid control is incorporated into each main line of the brake circuits. A first and second brake circuit communicate downstream of the shutoff valves with a feed system, which has devices for feeding brake fluid at different pressures to the first and second brake circuit.

Antilock brake system for providing different brake pressures to front

A hydraulic dual-circuit brake system with an anti-skid system and traction control in motor vehicles which has a four-channel hydraulic unit with electromagnetic control valves and a return pump having two separate pump elements. For supplying brake pressure during traction control, an additional hydraulic unit is provided, which has a charging valve for connecting the brake fluid tank to a pump element, which pump element is assigned to a brake circuit containing at least one driven wheel, and a reversing valve for alternatingly connecting this pump element to the master brake cylinder or the brake fluid tank. To provide economical brake pressure supply during traction control, the aforementioned pump element is embodied as a self-aspirating high-pressure pump, and a check valve having a flow direction toward the pump element is incorporated into the connection between the control valves disposed in the brake circuit assigned to this pump element and the inlet of the pump element.

Hydraulic dual-circuit brake system

A multi-circuit brake system having an anti-skid and traction control device for non-delayed, driver-activated braking. The multi-circuit brake system has a self-aspirating pump, which in case of traction control operation aspirates pressure medium from a pressure medium reservoir via an aspirating line and a main brake cylinder. A valve assembly in the brake line of the non-powered vehicle wheel is switched to maintain pressure in this case. A valve assembly, open in case of traction control operation, is located in the aspirating line. An auxiliary brake line with a pressure-controllable valve assembly originates at the aspirating line on the side towards the pump, when the valve assembly in the aspirating line is open, brake pressure generated by the driver by activating the main brake cylinder can be supplied to the wheel brake of the non-powered vehicle wheel. The invention is particularly suited for motor vehicles.

Hydraulic multi-circuit brake system including a traction and anti-skid

A vehicle brake system having at least two brake pressure lines, via which a master brake cylinder communicates with wheel brake cylinders, at least one valve is incorporated in each brake pressure line to close the brake pressure lines in the event of anti-skid control. Each brake pressure line is also assigned a return pump, which bypasses the valve. At least one valve, in the currentless state or with the absence of pressure buildup in a brake pressure line, blocks this brake pressure line and communicates with a control unit for pulsed opening upon pressure buildup in the brake pressure line. Because of the additional disposition of a pressure valve and check valve in a bypass around the pulsed valve, expensive pressure reducers are dispensed with, with little additional expense in the anti-skid control system. Even if the anti-skid control system fails, stability during braking is assured.

Anti-skid brake system for a vehicle

A vehicle brake system of the previously known type has a rear wheel brake booster, between a brake pressure source and an anti-skid apparatus associated with the rear wheels of the vehicle; the brake booster can be switched on by an electrically controllable switchover device. However, switching on of the rear wheel brake booster is effected at the onset of braking only if the anti-skid apparatus is in an operative functional condition. The complex structure of the switchover device in the form of a 3/2-way magnetic valve is a disadvantage. For simplification and economy, the switchover device is provided with an electrically controllable 2/2-way valve and a 2/2-way valve that is mechanically controllable by the stepped piston of the rear wheel brake booster and is built into this brake booster. An electrically controllable 2/2-way valve, which is a component of the anti-skid apparatus, is likewise triggered to activate the rear wheel brake booster.

Vehicle brake system having anti-skid apparatus

A hydraulic brake system for a vehicle including, brake pressure modulators that prevent the locking of vehicle wheels caused by excessively high braking pressures. Such brake pressure modulators include brake line blocking valves and cylinders with pistons, where upon piston displacement, pressure fluid escapes from the wheel brakes to lower the brake pressure. The displacements of the pistons are controlled via valve assemblies that are connected to a servo pressure source. Failure of the servo pressure source, if there is even a small leak of a valve assembly, can lead to at least partial loss of a brake force during a braking event. To recognize and indicate any leak that might be present, a control unit which acts upon the valve assemblies is arranged such that it directs the valve assemblies into various switching positions and in this process, via a pressure sensor, observes whether logically observed pressures are varying impermissibly.

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Stuttgart, Germany

Roland Holzmann