Robert Boschgmbh

Lothar Kirstein

Heinz Leiber

Waldemar Hans

Wolf-Dieter Jonner

Gerhard Wetzel

Guenther Schmidt

Helmut Staib

Roland Holzmann

Wolfgang Bernhardt

Heinrich Kochendorfer

Gerhard Brune

Walter Ropstorff

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 hydraulic dual-circuit brake system with an anti-skid system (ABS) and traction control (ASR) for motor vehicles having a four-channel hydraulic unit with four control valves; a return pump with two separate pump elements for each brake circuit; and two-low-pressure reservoirs connected to the inlets of the pump elements. To supply brake pressure in the traction control mode, an additional hydraulic unit is used, which has a precharging pump for feeding brake fluid from a brake fluid tank into each brake circuit containing a driven wheel, and having a valve unit, which in traction control operation disconnects the pump element associated to a brake circuit having at least one driven wheel from the master brake cylinder on the outlet side. For the sake of improved dynamics during brake pressure buildup, a shutoff element, which in traction control operation disconnects the low-pressure reservoir from the precharging pump, is provided between the low-pressure reservoir and the associated pump element.

Hydraulic dual-circuit brake system with anti-skid and traction control

A throttle in a hydraulic system having a cross section which varies as a function of fluid flow in the hydraulic system. A throttle restriction includes a bore with a wire end segment extending in the bore that reduces the cross section of the bore. The wire end segment has an end face, facing counter to the pressure fluid flow, on which flow forces are operative. The flow forces are capable of positively displacing the wire end segment out of the bore counter to a spring restoring force. The throttle can for instance be used in the hydraulic brake systems in which peaks in volumetric flow and pressure are to be reduced. The throttle can also be used wherever self-cleaning of the throttle restriction is desired.

Throttle in a hydraulic system

A hydraulic brake system with an anti-skid system (ABS) and traction control (ASR) for motor vehicles having a hydraulic unit with at least one control valve and a return pump with at least one pump element embodied as self-aspirating, which element is operative in the brake circuit containing the at least one driven wheel. To furnish brake pressure during traction control, a valve assembly is provided. For the sake of simplicity in the embodiment of this valve unit, it has not only a charge valve disposed in an intake line between the pump element and the brake fluid tank but also a reversing valve, incorporated between the master brake cylinder and the control valve and having three hydraulic control inlets and a restoring spring, of which one control inlet communicate with the outlet of the pump element, and the two control inlets counteracting this control element communicate with the valve inlet and outlet, respectively. A check valve having a parallel throttle provides for an adequate pressure difference for reversal of the reversing valve upon a buildup of pressure at the outlet of the pump element.

Hydraulic brake system

A hydraulic dual-circuit brake system with diagonal brake circuit distribution, an anti-lock system ABS and traction control ASR for motor vehicles having a four-channel hydraulic unit with control valves and a return pump. To achieve the ASR function, a third, self-aspirating pump element embodied as a high-pressure pump on the return pump is driven jointly with the return pump, and the wheel brake cylinders of the two driven wheels (HR, HL) are additionally connected--bypassing the control valves--to the third pumping element via a magnetic valve assembly. If at least one of the driven wheels (HR, HL) is spinning, the third pumping element is activated. The magnetic valve assembly is switched over, and the control valve for the slipping driven wheel is switched to 'pressure holding'. The brake pressure generated by the pumping element is thus fed into the wheel brake cylinder of the spinning driven wheel (HR, HL), and the spinning driven wheel (HR,HL) is slowed down.

An hydraulic dual-circuit brake system with an anti-skid system (ABS) and traction control (ASR) for motor vehicles has a four-channel hydraulic unit with electromagnetic control valves and a return pump with two separate pumping elements for each brake circuit. To supply brake pressure in traction control operation, an additional hydraulic unit is provided, which portions of connect the fluid tank to the return pump and switch the alternating connection of the outlet of the return pump to the master brake cylinder or to the brake fluid tank. For a rapid reduction of brake pressure in the wheel brake cylinders of the driven wheels at the onset of braking during traction control operation, the switch portion has at least one 3/3-way magnetic valve with a pressure limiting valve disposed in a valve bypass. This 3/3-way magnetic valve connects the outlet of the pumping element associated to one driven wheel to the master cylinder in a first position, and in a third position it connects it directly to the brake fluid tank. In a second position, all the working connections are blocked, so that a brake supply pressure can be built up.

A traction control system adapted to an anti-skid control system including a third valve assembly disposed between a pressure fluid container and a first valve assembly, a line is established to an inlet of a pump which in the traction control situation pumps a quantity of pressure fluid at a certain pressure into a line, closed off by a second valve assembly, between the first valve assemblies and the second valve assembly.

Anti-skid and traction control system

An electromagnetic 3-way valve arrangement having two valves, each controlled by a separate armature of a single coil solenoid, is described. The top end of each armature has a self-aligning closing element, and the two armatures are held apart by springs acting against an intermediate member, which also contains the valve seat for the lower armature. When deenergized, these springs act against the armatures to close the upper valve and open the lower valve. When the solenoid coil is partially energized, it moves the lower armature upward to close the lower valve also. When the solenoid coil is fully energized, it moves the upper armature downward to open the upper valve. If desired, the armature can be disposed within the solenoid so that the upper armature is operated at partial energization, and the lower armature at full energization of the solenoid coil.

Growing community of inventors

Ditzingen, Germany

Lothar Kirstein