Daimler-benz Ag

Daimler-benzaktiengesellschaft

Hellmut Krohn

Reinhard Resch

Manfred H Burckhardt

Werner Kruse

Jurgen Frank

Franz Brugger

Horst Grossner

Andreas Pachner

Hans-Jorg Florus

Friedrich Solleder

A propulsion control device for a motor vehicle which has a permanently balanced all-wheel drive, wherein the drive slip thresholds at which the control responds in the sense of a braking action, is increased as a function of the velocity and decreased as a function of the transverse acceleration. The acceleration thresholds, at which the control responds, are lowered as a function of the transverse acceleration. In the case of travel in a straight line, the lowest of the wheel peripheral velocities is taken as the reference velocity relative to which the drive slip thresholds are fixed. In the case of travel in a curve, the average of the wheel peripheral velocities of the left-hand side and right-hand side vehicle wheels is taken as the reference velocity for the vehicle wheels on the left-hand side and the right-hand side of the vehicle, respectively. From the time t.sub.0 at which the control at one of the vehicle wheels comes into operation, the velocity of this vehicle wheel is updated in accordance with the expression

Device for propulsion control for a motor vehicle with all-wheel drive

A floating-caliper disc brake is designed to prevent both tangential and radial oblique wear of the brake linings, especially under high brake stress. To achieve this, the floating caliper, which is guided displaceably on a brake carrier in the direction of the disc axis and carries a brake piston and which engages over the brake disc, forms a frame which in the transitional region of the transverse frame leg on the run-out side, extending in the direction of the disc axis, and of the longitudinal frame leg supported on one brake pad is more pliant than in the transitional region between the longitudinal frame leg and the transverse frame leg located on the run-in side. The brake piston is arranged in the frame so as to be offset in the forward direction of rotation of the brake disc relative to the surface center of gravity of the brake pad actuable by the said brake piston, and the longitudinal frame leg supported on one brake pad extends level with the brake piston.

Floating-caliper disc brake

In a motor vehicle with an all-wheel drive, which is equipped with a thrust and anti-lock control device, each wheel brake has assigned to it a pressure modulator, within which a control-pressure space, into which the outlet pressure of a brake unit can be fed, and an outlet-pressure space, to which a particular wheel brake is connected, are limited by a control piston. This control piston ensures the hydraulic separation of the control circuit from the outlet circuit. Two drive pistons supported on the control piston limit, within the modulator housing, two drive-pressure spaces which, by being connected alternately to the outlet of an operating-pressure source, can control pressure build-up and pressure-reduction control movements of the control piston. To control the connection of the drive-pressure spaces to this operating-pressure source, there are two-way solenoid valves which can be activated by means of output signals from an electronic control unit provided jointly for the anti-lock control and the thrust control.

Device for anti-lock control and for thrust control on a motor vehicle

A thrust-control device for a motor vehicle having wheels driven on one axle, with a dual-circuit brake system having a tandem main brake cylinder and a brake booster supplied from a special auxiliary pressure source, with an anti-lock system having a brake-pressure medium return device, and with a pressure accumulator serving for thrust control, is extended for use on vehicles with a connectable or permanent all-wheel drive, to the effect that a stop valve is arranged in the brake circuit of the wheels of the further axle and there is a control valve controlling the accumulator pressure and acting on a pressure modulator, the pressure modulator influencing the brake pressure in the brake circuit of the wheels of the further axle when the drive of these wheels is connected and drive slip occurs. This simple extension requires no additional accumulator and makes it possible to preserve the independence of the brake circuits.

Thrust-control device for a motor vehicle

A hydraulically power-assisted dual circuit brake system for road vehicles combined with an anti-locking brake system has a stepped tandem master cylinder and a primary piston. The primary piston includes a ring piston which is displaceable in a larger cylinder step and a plunger which is displaceable in said ring piston. A pre-pressure acting on the control area of the plunger of the primary piston is built up by pedal actuation of a further plunger. This pre-pressure operates as a reference pressure and is also coupled into a proportional control valve. The proportional control valve provides a control output pressure which is taken from the auxiliary pressure source and is higher. The control output pressure is used to impinge the ring piston and thereby move the plunger of the primary piston. With use of the ABS control, at least a secondary brake circuit, in a special design a primary brake circuit as well, is switched over from static to dynamic operation. In dynamic operation, the output pressure of the proportional control valve is used to operate the selected brake circuit. A stroke sensor monitoring the displacement stroke of the ring piston generates an output signal independently of the ABS control, which signal triggers the changeover of both brake circuits to dynamic operation when a threshold value of the ring piston stroke is reached.

Hydraulic dual circuit brake system for road vehicles

In a vehicle equipped with a propulsion control system combined with an anti-blocking system, a pressure reservoir provided as a brake pressure supply-source which can be charged by means of the return pump of the anti-blocking system, whereby the charging operation is valve-controlled so that the feed from the return pump is directed into the pressure reservoir during pressure-reduction phases of the propulsion control system, the pressure reservoir can also be charged, outside the control phases of the propulsion control system, either by operating the driver's brake pedal or by automatic activation of a charging circuit accompanied by the operation of the return pump.

Installation for charging a pressure reservoir provided as a pressure

A brake valve useable in conjunction with a vehicle braking system is monitored by an anti-locking device and operable by a brake pedal through a trailing or simulating spring. The brake valve is provided with a control slide valve for regulating a metered feed of the pressure medium conducted from a pressure source to the wheel brake cylinders of the braking system. The pressure medium is furthermore relievable at the wheel brake cylinders by anti-lock valves. The control slide valve cooperates with at least two emergency pistons freely traversible during normal operation of the braking system. Each of these emergency pistons are mechanically operable from the brake pedal in case of failure of the energy supply or of a brake circuit after a valve associated with the respective pistons has been closed.

Brake valve

A servo brake system with at least two circuits, equipped with a tandem master cylinder, in which two working pistons are arranged coaxially one behind the other; a transmission shifting device thereby automatically shifts in case of failure of the servo installation to a larger pedal travel with a mechanically applied brake pressure that is reduced within permissive limits; the working piston of the actuating side thereby includes a bore coaxial to the other working piston, in which a plunger piston is guided which is actuatable by the input piston.

Servo brake system

A brake force control system for vehicles, especially for motor vehicles in which one or several electrical signals dependent on the wheel acceleration are compared with predetermined threshold values and in which the resultant electrical signals are utilized for the control of actuating elements such as solenoid valves in the brake circuit, whereby the electrical acceleration signals are weighted in a manner known as such and this weighting is adapted to be influenced or even discontinued when exceeding the threshold value and/or in dependence on the polarity of the acceleration signal.

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Esslingen, Germany

Hellmut Krohn