Robert Boschgmbh

Guenter Kaes

Alwin Stegmaier

Friedrich Megerle

Guenther Hohl

Wolfgang Maisch

Norbert Alaze

Erich Ludewig

Walter Steinhauser

Wolf-Dieter Jonner

Guenter Wolff

Hans-Joerg Fees

Werner Wilde

Alexander Eichhorn

Michael Kollers

A hydraulic unit for wheel slip control, which is located between a master cylinder and wheel brake cylinders. Reflection damping devices are installed in main brake lines located between the hydraulic unit and the master cylinder which damp pressure waves that originate at control valves of the hydraulic unit. When the control valves are triggered in the wheel slip control mode the pressure waves are largely kept away from the master cylinder. By the means of length adaptation of the main brake lines, the brake lines can also contribute to the damping.

Hydraulic vehicle brake system with a hydraulic unit for wheel slip

Hydraulic vehicle brake system with a hydraulic unit for wheel slop

Positive connection of a magnetically operated valve to a housing block,

A structurally simplified brake system which increases its functional reliability. The brake system has a brake pressure line extending between a master brake cylinder and a wheel brake. A shutoff valve is connected in parallel with a pressure limiting valve disposed in the brake line. A high-pressure pump toward the wheel brake side is capable of feeding pressure fluid into the line when the shutoff valve is closed. If a response pressure of the pressure limiting valve is exceeded, the pressure fluid can be diverted back to the master cylinder. The shutoff valve has a valve seat toward the wheel brake and a closing member toward the master cylinder which closing member is capable, by the action of a magnetic force on an armature of engaging the valve seat. A compression spring is disposed between the armature and the closing member and in the valve closing position exerts a closing force, adapted to the response pressure, upon the closing member. The shutoff valve and the pressure limiting valve are thus attained in a single valve unit.

Hydraulic brake system for motor vehicles

A quiet closure check valve, including a housing having a valve seat toward the housing, a ball is associated with the valve seat to close the valve. The ball is received longitudinally displaceably in a recess of a spring-loaded support element that is defined by a bottom and a collar-like portion. Upon closure of the check valve, the support element rests on the housing, by spring action. The ball is lifted from the bottom of the support element and applied to the valve seat by the pressure of the fluid, in a manner free of spring forces. In this way, bothersome vibration of the ball is avoided.

Check valve

A brake system having a pressure control valve assembly with an inlet valve in a brake line between a master brake cylinder and a wheel brake cylinder. The brake system is also equipped with a precharging pump and a return pump. A charging valve is disposed in a feed line connecting the two pumps. In phases of brake pressure holding and brake pressure reduction upon traction control, the pumping of brake fluid through the continuously operated return pump by the precharging pump is intended to be suppressed. When the precharging pump and the return pump are driven by a common drive motor, the charging valve, which is embodied as a 2/2-way valve, assures that when the anti-skid system becomes operative an exchange of brake fluid between the precharging pump and the return pump is suppressed. When the traction control becomes operative, contrarily, the valve enables pumping of brake fluid from the precharging pump to the return pump, but only whenever the pressure control valve is switched for pressure buildup.

Hydraulic brake system with anti-skid system and traction control for a

A slip control system for a hydraulic brake system of a vehicle, which comprises a pressure generator having a plunger piston, which plunges into a cylinder filled with brake fluid and is connected to a rack. For the forward drive of the plunger piston, an electric drive motor is provided, which via a gear drive drives a pinion meshing with the rack. For the return drive of the plunger piston, a spiral spring is used that engages on one end with pinion shaft and on the other is supported on the pressure generator housing. The use of the spiral spring makes a short axial structural length of the pressure generator attainable. A grip roller free-wheel clutch is also provided in the drive train between the motor and the rack. The grip roller free-wheel clutch effects an uncoupling of the gear drive and the drive motor when the rack, at the end of the return stroke, strikes a stop of the pressure generator housing. This prevents damage to the gear drive and motor.

Electric-motor-drivable pressure generator for a hydraulic brake system

A brake system including a traction control apparatus having at least one pressure generator 35, which has a cylinder 60 for receiving and expelling brake fluid by means of a piston 60. The cylinder 60 is connected, with a valve 72 actuatable as a function of the motion of the piston 50, to a pressure course between the master brake cylinder and a wheel brake cylinder. To attain a short structural length, on the one hand, and a long stroke of the pressure generator on the other, the piston is embodied as a rod piston; it is connected to a coaxially extending hollow cylinder 40 that envelops the piston 50 in the cylinder 60; the hollow cylinder 40 is longitudinally guided and is provided with a racklike set of teeth 41 on its outside for the engagement of a motor drive mechanism 43 for driving the piston relative to the cylinder.

Pressure generator for a hydraulic brake system for a vehicle

A known valve controllable by means of an electromagnet includes at least one spring installed with prestressing, the prestressing of which must be within a relatively narrow tolerance range, if the valve is to function properly. Since then, when the valve has been assembled, the spring, which is subject to manufacturing tolerances, and other components subject to manufacturing tolerances, have been replaced with other components of different dimensions until a suitable prestressing was arrived at. The invention seeks to avoid this replacement work. The problem is solved by disposing an element that is displaceably installed so as to overcome frictional forces, and one end of a spring is supported on this element. One or more such elements are advantageously usable in multi-position magnetic valves, which for instance belong to vehicle brake systems and in particular to their anti-skid systems.

Electrically controllable 3-way valve

A magnetic valve with reversible flow for use in anti-skid brake systems (ABS) has an armature displaceably supported in a valve housing within a control coil. A sealing element is moved by the armature and a stationary valve seat is associated with the sealing element. The armature includes a bottom which communicates via openings with an inflow region including the sealing element, a sealing element holder, and a valve body. The sealing element formed as a sealing ball and the sealing element holder formed as a perforated disk are embodied such that within predetermined stroke and flow ranges, an aspiration effect due to the flowing medium ensues, and a retaining element provided in the form of a permanent magnet acts upon the armature and the retaining element is overcome upon electrical triggering of the magnetic valve, resulting in a large flow cross section for normal braking, and a reduced flow cross section in ABS operation.

Tests of electrohydraulic switching valves with fluidic ball elements

A magnetic valve with a connection device is proposed, in which the housing is rotatable relative to the connection device, which encompasses a connector stub formed onto the housing. Embodying the connection device as a male fitting enables the alignment of the housing and the cable plug located on it, which is especially useful when the magnetic valve is installed in a wheel connection of a master brake cylinder. In another version, in which the connector stub is connected to the connection device positively with a snap-in ring, the magnetic valve can be inserted even at inaccessible locations. If the connection device is embodied as part of a brake cylinder, then the magnetic valve can be inserted directly, and the result is a connection that is secure against manipulation.

Magnetic valve with connection device for brake systems

The proposed vehicle brake system has a hydraulic brake booster, a master brake cylinder, wheel brakes and a pressure source for operating the brake booster. The vehicle brake system also has an anti-skid device, which comprises an auxiliary cylinder with an auxiliary piston and valve assemblies. In the anti-skid situation, the auxiliary piston is acted upon, controlled by one of the valve assemblies, and it acts counter to the brake booster and thereby lowers the pressure in the master brake cylinder. By stopping the valve assembly that is associated with a wheel threatening to skid, the brake pressure in the associated wheel brake drops. Valve assemblies are also further developed such that by including the valve assembly, drive slip at driven wheels can be limited by means of pressure from the pressure source.

Hydraulic vehicle brake system with anti-skid device

In a so-called starting aid for motor vehicles, synchronism in the rpm of the drive wheels during starting is provided by feeding a brake pressure derived from the rpm difference of the drive wheels into the wheel brake cylinder associated with the wheel having the higher rpm. To this end, one brake pressure controller having a control piston and a valve is installed in each brake line to the wheel brake cylinders of at least two wheel brakes. The control pistons are actuated in opposite directions via a final control element to which a control signal derived from the rpm difference is supplied. Upon displacement, whichever control piston is driven closes the valve and feeds brake pressure into the associated wheel brake cylinder. In order that the starting aid will have a high control speed and a small structural volume, the final control element is embodied as an electric control motor.

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Stuttgart, Germany

Guenter Kaes