Fluid-pressure and analogous brake systems – Speed-controlled – Front-rear axle apportioning or speed difference
Patent
1996-08-19
1999-04-06
Butler, Douglas C.
Fluid-pressure and analogous brake systems
Speed-controlled
Front-rear axle apportioning or speed difference
188156, 188162, 188349, 3031135, 3031134, 303155, 3031161, 303DIG4, 303 3, B60T 826, B60T 842, B60T 1358
Patent
active
058907785
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is based on a brake system for a passenger car road vehicle. One such brake system is already known (U.S. Pat. No. 5,234,262), in which the pressure modulators in the anti-lock mode not only act by means of a piston on a closing member of a check valve in the respective brake line but also vary the volume of a cylinder chamber for receiving pressure fluid drawn from the associated wheel brake. Each of the pressure modulators has an electric motor, which via a screw spindle drive displaces the pistons in both directions. This known embodiment requires a relatively major effort and expense for the pressure modulators and for controlling the current of the motor. Moreover, the dynamics of anti-lock control are reduced by the inertia of the piston drive.
An anti-lock brake system known from European Patent Disclosure EP-A 253 157 has a pressure modulator, disposed between a master cylinder and a wheel brake, that comprises an electric motor-drive pump and a parallel-connected electromagnetically actuated valve. In anti-lock control, the pump pumps pressure fluid from the wheel brake to the master cylinder, while the switched-over valve limits the flow of pressure fluid to the master cylinder and to the wheel brake. This embodiment and mode of operation of the pressure modulator allows only poor control quality.
OBJECT AND SUMMARY OF THE INVENTION
The object of the invention, in the brake system mentioned at the outset, is to embody an anti-lock arrangement of simple design and high control quality that is associated with the front axle wheel brakes, and to monitor the action of the wheel brakes of the brake system in the sense of closed-loop control.
This object is attained with the characteristics recited hereinafter.
ADVANTAGES OF THE INVENTION
The brake system according to the invention has the advantage over the prior art that it can be embodied more economically than that of the prior art, yet nevertheless meets the demands for a brake system for small and hence lightweight vehicles with front-wheel drive. Moreover, the brake system of the invention has high dynamics, since the shutoff valve has very short switching times and the pump is continuously on in the anti-lock mode. The expenditure for controlling the anti-lock arrangement is accordingly low. Because of the monitoring of the wheel brakes with sensors, the control unit that evaluates the sensor signals can regulate the action of the wheel brakes, i.e. in closed-loop fashion, in accordance with the pedal actuation.
BRIEF DESCRIPTION OF THE DRAWING
An exemplary embodiment of the invention is shown schematically in the drawing, in a brake system with hydraulic actuation at the front axle and electric actuation at the rear axle, and is described in further detail in the ensuing description.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT
The brake system 1 shown in the drawing is intended for use in a lightweight front wheel drive passenger car. It has both an electrical and a hydraulic service brake system. The brake system 1 is also provided with a device for controlling wheel slip.
In detail, the brake system 1 has a dual-circuit master cylinder 3, actuatable by a brake pedal 2, with a pressure fluid reservoir 4. In brake circuit I, a brake line 5 leads from the master cylinder 3 to a hydraulic wheel brake 6, which is associated with the right front wheel, not shown, of the vehicle. Brake circuit II has a brake line 7, which communicates with a hydraulic wheel brake 8 of the left front wheel, also not shown, of the vehicle. The hydraulic service brake system is thus associated with the front axle of the vehicle.
The two brake circuits I and II of the hydraulic service brake system are embodied identically; below, brake circuit I will therefore be described in detail.
Located in the brake line 5 between the master cylinder 3 and the wheel brake 6 is a 2/2-way valve, acting as a shutoff valve 11, with a spring-actuated normally open position and an electromagnetically actuated blocking position. The shutoff valv
REFERENCES:
patent: 4865399 (1989-09-01), Atkins et al.
patent: 4875741 (1989-10-01), Ozawa et al.
patent: 4917445 (1990-04-01), Leppek et al.
patent: 5141296 (1992-08-01), Arikawa
patent: 5163743 (1992-11-01), Leppek et al.
patent: 5234262 (1993-08-01), Walenty et al.
patent: 5261731 (1993-11-01), Yogo et al.
Butler Douglas C.
Greigg Edwin E.
Greigg Ronald E.
Robert & Bosch GmbH
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