Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Patent
1992-12-18
1994-04-05
Butler, Douglas C.
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
3031161, 3031191, 303111, B60T 832, B60T 848, B60K 2816
Patent
active
052998584
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates, in general, to vehicle braking systems and, in particular, to a brake system for controlling both brake slip and traction slip.
German Patent Application DE 38 32 023 A1 describes a generic anti-lock-controlled brake system working in accordance with the recirculation principle. The pump is of the self-priming type in order to be able to supply pressure medium from the pressure medium storage reservoir through the brake line, via the tandem master cylinder, into the wheel brake of the spinning wheel for the purpose of traction slip control However, a vacuum must be prevented from forming in the wheel brake due to the self-priming action of the pump. To this end, a non-return valve opening in the direction of suction is built into the return line of the wheel brake which leads to the suction side of the pump, the pre-pressure of this non-return valve being at least as high as the atmospheric pressure.
If the brake circuit is arranged so that only the wheel brakes of driven and non-driven wheels are, at a particular time, in one brake circuit, (i.e. the so-called black-and-white arrangement) or an all-wheel drive, the problem is thus solved. The situation, however, is different with a brake system of the diagonal type when the vehicle has a one-axle drive. Then either brake circuit will operate on one brake of a driven wheel and one brake of a non-driven wheel at a time. In case of traction slip control, on the one hand, pressure should be built up only in the brake cylinders of driven wheels. On the other hand, it is also necessary to protect the brakes of the non-driven wheels from a vacuum. If, during a traction slip control operation, the pump primes through the brake line and the tandem master cylinder, it will generate a vacuum of about 0.8 bar. Depending on the throttling effects which appear between the reservoir and the connection of the suction line to the brake line, this vacuum may propagate, weakened, as far as the brake of the non-driven wheel if the shut-off valve is located between the feed lines to the wheel brakes of the driven wheel and of the non-driven wheel. However, if the two wheel brakes are located, relative to the master cylinder, beyond the shut-off valve, then the brake of the non-driven wheel would also be applied during traction slip control A complicated circuit logic, closing the corresponding inlet valve during traction slip control, is comparatively intricate and expensive If the shut off valve is arranged between the brake feed lines, closing of the inlet valve, as a rule, will be of no avail because, generally, non-return valves are connected in parallel to the inlet valves, with the non-return valves opening in the outlet directions and, thus, similarly permitting the formation of a vacuum.
SUMMARY OF THE INVENTION
It is thus an object of this invention to protect, in a reliable manner, the brakes of the non-driven wheels from vacuum and pressure-build during traction slip control without using any additional auxiliary means.
This object is achieved, according to the present invention, by a particular arrangement of the brake of the non-driven wheel and two non-return valves. In case of traction slip control, because of the shut-off valve between the feed lines leading to the inlet valves, only the brake of the driven wheel will be filled by the pump pressure, without the inlet valves being actuated The wheel brake of the non-driven wheel can only be filled via its feed line which, relative to the shut-off valve, is on the master-cylinder side, (i.e., only during a pedal-operated braking operation). Pressure medium reduction is effected via an auxiliary line leading to the delivery side of the pump. No vacuum can form on this side of the shut-off valve. The wheel brake of the non-driven wheel will also be protected even if, for safety reasons, non-return valves are provided in parallel to the inlet valves, which, generally, is the case.
BRIEF DESCRIPTION OF THE DRAWING
Further advantageous characteristics
REFERENCES:
patent: 5152586 (1992-10-01), Burgdorf
patent: 5178442 (1993-01-01), Toda et al.
patent: 5234264 (1993-08-01), Willmann et al.
Alfred Teves GmbH
Butler Douglas C.
Lewis J. Gordon
Seitter Robert P.
LandOfFree
Brake system with a device for controlling both the brake slip a does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Brake system with a device for controlling both the brake slip a, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brake system with a device for controlling both the brake slip a will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-507255