Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Patent
1994-08-09
1995-10-24
Butler, Douglas C.
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
303 841, 303 87, 3031161, 3031171, B60T 832, B60T 844
Patent
active
054604362
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to brake systems and more particularly relates to slip-controlled hydraulic brake systems .
A brake system of this general type is known from DE-38 42 699 A1. To avoid loud switching noises at the inlet valves, the brake system described therein is furnished upstream of each inlet valve with a differential pressure limiter which, in each case, shuts off further pressure fluid supply to the inlet valves when the pressure upstream of the inlet valves exceeds the pressure in the wheel brakes by a predefined amount. This approach has proved efficient, since the switching noises were greatly diminished due to the limited pressure difference across the inlet valves. However, it has a disadvantage in that the installation of four differential pressure limiters render the brake system much more costly to produce and complex in design.
The object of the present invention is to provide a simpler arrangement for noise reduction without limiting the operational reliability of the brake system.
SUMMARY OF THE INVENTION
This object is achieved by providing one common differential pressure limiter for several wheel brakes. Since only one of the wheel braking pressures can act as a reference pressure in each case, a pressure selector is inserted between the control lines and the differential pressure limiter which, depending on the respective pressure conditions in the wheel brakes, selects one of the two wheel braking pressures which is to serve as a reference pressure.
When the pressure selector selects in each case the lowest of the wheel braking pressures, the switching noises are diminished compared to the selection of the highest of the wheel braking pressures. However, depending on the dimensioning of the brake system, it may occur that too little braking force is applied. Therefore, depending on the brake system, predetermined selection criterion is applied.
This type of noise reduction has proved effective especially in those brake systems in which a high-pressure accumulator is available which furnishes the wheel brakes with pressure fluid during traction slip control, since the pressure is applied abruptly at the inlet valves.
Yet, the present invention is also applicable on all other brake systems which are equipped with an auxiliary pressure source (e.g. with a pump).
Further advantageous features can be gathered from the description of a preferred embodiment of the inventive brake system of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is the inventive brake system of the present invention.
FIG. 2 is a differential pressure limiter with a pressure selector inserted ahead, as is used in the brake system of FIG. 1.
FIG. 3 is another second embodiment of the pressure selector of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The brake system according to FIG. 1 comprises a master brake cylinder 1 which is in communication with the pressure fluid reservoir 2. The master brake cylinder 1 serves to furnish the brake circuits I and II with pressure fluid, only brake circuit I thereof being illustrated.
The brake line 3 leads from the master brake cylinder 1 by way of the shut-off valve 4 into two brake branch lines 5 and 6 which lead to the wheel brakes 9 and 10 by way of the inlet valves 7 and 8, respectively. Extending from the wheel brakes 9 and 10 is a return branch line 11 and 12, respectively. Lines 11 and 12 return fluid to pressure fluid reservoir 2 by way of common return line 15. Connected to the pressure fluid reservoir 2 is also the pump 17 by way of the suction line 16. The pump 17 supplies fluid into the pump line 18 which divides into the accumulator line 19 and the auxiliary-pressure line 27. The auxiliary-pressure line 27 ends into the brake line 3 between shut-off valve 4 and the inlet valves. The accumulator line 19' connects the differential pressure limiter 20 to the accumulator-charging valve 21. The pressure accumulator 22 is connected to accumulator-charging valve 21 by way of line 19".
The di
REFERENCES:
patent: 5007687 (1991-04-01), Kircher et al.
patent: 5094511 (1992-03-01), Becker et al.
patent: 5098173 (1992-03-01), Beck et al.
patent: 5129714 (1992-07-01), Latarnik
patent: 5188433 (1993-02-01), Reinartz et al.
patent: 5251971 (1993-10-01), Reinartz et al.
patent: 5312174 (1994-05-01), Beilfuss et al.
Beck Erhard
Volz Peter
Butler Douglas C.
ITT Automotive Europe GmbH
LandOfFree
Slip-controlled brake system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Slip-controlled brake system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Slip-controlled brake system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1882377