JPS6355456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a skid control device for a motor vehicle, which comprises a brake valve whose brake conduit leads to a brake cylinder of an axle, and a brake valve whose brake conduit leads to the brake cylinder of an axle. and at least one skid control valve for individually monitoring the pressure in the branch lines (DE 25 06 284 A1).

Vehicles with individually controlled wheels can make full use of the coefficient of friction. For example, extreme road conditions with muddy snow on one side and dry asphalt on the other side can lead to dangerous driving conditions for some vehicles. This applies to motor vehicles with short wheel spacing, such as passenger cars, semi-trailers or similar motor vehicles.

In the above-mentioned automobiles, under extreme road conditions, even if the steering angle is large and the coefficient of friction is fully utilized, the necessary balance may not be achieved in some cases. In this case, the vehicle turns about its yaw axis and becomes completely unstable.

This is prevented in known skid control systems in that, in the event of strongly different brake pressures, a differential pressure limiting valve reacts and the differential pressure is reduced. In this way, the braking force coefficient is no longer fully utilized, but the maximum lateral guiding force is maintained, so that driving stability is guaranteed. Known skid control devices include two piston members and two valves actuated by the piston members. The aforementioned piston members require special sealing members. This not only increases the complexity and cost of the valve, but also increases the friction and thus the necessary response pressure, in particular the starting force.

SUMMARY OF THE INVENTION The object of the invention is to improve the skid control device mentioned at the outset, so that the construction of the skid control device is simple and the skid control device responds sensitively and reliably.

SUMMARY OF THE INVENTION An object of the present invention is to provide a skid control device for a motor vehicle, which comprises a brake valve, from which a brake conduit leads to left and right brake cylinders of an axle, and in which each brake of the brake conduit is connected to the left and right brake cylinders of an axle. at least one skid control valve for individually monitoring the pressure in the branch conduits leading to the cylinder; an overflow valve connected to each branch conduit downstream of the skid control valve; , in a type that uses a differential pressure limiting valve that can reduce excess brake pressure generated in one branch conduit by directing it to the other branch conduit via the left and right connecting conduits, the differential pressure limiting valve is a dual type. overflow valves, the pressure medium overflowing from one overflow valve is guided directly under the closing body of the other overflow valve, and the pressure medium overflowing from the other overflow valve is directed to the overflow valve of the one overflow valve. The solution was to lead directly under the closure body of the valve.

An advantage of the invention is that because no piston member is used, fewer components are required for the differential pressure limiting valve, which makes the response of the skid control device more reliable and sensitive. .

The invention will now be explained with reference to the drawings: The braking device has a two-system brake valve 1 which channels compressed air stored in two tanks 2 and 3 into two brake conduits 4, Supply to 5. Brake line 4 is a brake line for the rear axle, and brake line 5 leads to the front axle. There is a steering wheel on the front axle and the pressure in the brake conduit 5 must be monitored so that unnecessary steering angles are not required.

A two-pass skid control valve 6 is arranged in the brake conduit 5. In this skid control valve 6, the brake conduit 5 branches into two branch conduits 5', 5'', and the skid control valve 6 connects these branch conduits 5', 5'' to one common 3 port 2 position. Valve 40 and each branch conduit 5'
A detailed description of such monitoring is given in German Patent Application No. 2,625,502. Therefore, a detailed explanation will not be given here because the mode of operation of the skid control valve is not a subject of the present invention.

The two branch lines 5' and 5'' lead from the skid control valve 6 to a brake cylinder 8 and 8', respectively, on the left-hand side of the vehicle body and on the right-hand side of the vehicle body.

The skid control valve 6 is provided with a differential pressure limiting valve 7 which is connected to two overflow valves 9, 10 and to both branch conduits 5',
5". Each overflow valve 9, 10 is composed of a valve seat 13, 14 fixed to the casing, a closing body 15, 16, and a , 16 to the valve seat 13,
It is composed of valve springs 17 and 18 that press against valve spring 14.

The skid control device operates as follows: When the brake is not applied, the differential pressure limiting valve 7 is in the rest position shown. Furthermore, the closing bodies 15, 16 do not move in the case of normal braking or in the case of skid control control, which is equivalent to the case of normal braking. Brake air can flow past the skid control valve 6 in both directions.

However, if the two-pass skid control valve 6 delivers a higher pressure to one branch line 5' or 5'' than to the other branch line 5'', as occurs, for example, when driving on road surfaces with different coefficients of friction. , the differential pressure becomes so high that the running stability of the vehicle is disturbed around the yawing axis.

In this case, for example, 2 ports 2 on one side of the vehicle
The position-type pressure maintenance valve is switched to pressure maintenance, and the brake cylinder 8 or 8' is relieved of pressure via the other open pressure maintenance valve and the switched-off three-port two-position valve. The resulting strong pressure difference overcomes the force of the valve spring 17 or 18, and the corresponding overflow valve 9 or 10 is opened and the brake conduit in question is relieved into the other brake conduit. In this other brake line, the pressure maintenance valve is open, so that excess pressure is released to the pressure relief point. Further pressure increases, which would further increase the pressure difference to the opposite brake cylinder, are thus prevented.

The force of the valve springs 17, 18 and the cross section of the valve seats 13, 14 determine the opening pressure of the overflow valves 9, 10. In this way, the moment about the yaw axis of the vehicle is limited and stability in the direction of travel is maintained.

By varying the force of the valve spring and the cross-sectional area of the valve seat, it is possible to set different differential pressure limiting forces as required.

FIG. 2 shows an embodiment in which the differential pressure limiting valve 20 is arranged outside the skid control valve 6. In this case, the two overflow valves of the differential pressure limiting valve 20 are arranged directly next to each other in their own housing.

FIG. 3 also shows a differential pressure limiting valve 21 located apart from the skid control valve 6. The overflow valves of this differential pressure limiting valve 21 have only one common valve spring 22, but for each overflow valve there is in each case one check valve 2.
3 and 24 are provided.

Of course, the differential pressure limiting valve 21 can also be arranged inside the skid control valve 6.

[Brief explanation of drawings]

The drawings show a plurality of embodiments of the present invention, in which FIG. 1 is a sectional view of a skid control device having a differential pressure limiting valve, and FIG. 2 shows another embodiment of the differential pressure limiting valve. Schematic diagram, FIG. 3 is a schematic diagram showing yet another embodiment of the differential pressure limiting valve. 1... Brake valve, 2, 3... Tank, 4, 5
...Brake conduit, 5', 5''...Branch conduit, 6...
...Skids control valve, 7...Differential pressure limiting valve,
8, 8'... Brake cylinder, 9, 10... Overflow valve, 11, 12... Left and right connection conduit, 1
3, 14... Valve seat, 15, 16... Closing body, 1
7, 18... Valve spring, 20, 21... Differential pressure limiting valve, 22... Valve spring, 23, 24... Check valve, 4
0...3 port 3 position valve, 41, 42...pressure maintenance valve.

Claims (1)

[Scope of Claims] 1. A skid control device for an automobile, comprising a brake valve 1, from which a brake conduit 5 leads to left and right brake cylinders 8, 8' of one axle. , the brake conduit 5
at least one skid control valve 6 for individually monitoring the pressure in the branch conduit 5', 5'' leading to each brake cylinder 8, 8', downstream of said skid control valve 6. an overflow valve 9, 10 connected to the branch conduit 5', 5'', with the overflow valve 9, 10,
Differential pressure limiting valves 7 and 2 are capable of reducing excess brake pressure generated in one branch conduit 5' by directing it to the other branch conduit 5'' via left and right connecting conduits 11 and 12.
In the format where 0 and 21 are used,
The differential pressure limiting valves 7, 20, 21 have dual overflow valves 9, 10, and the pressure medium overflowing from one overflow valve 9 is guided directly below the closing body 15 of the other overflow valve 10. A skid control device, characterized in that the pressure medium overflowing from the other overflow valve 10 is guided directly below the closing body 16 of the one overflow valve 9. 2 It has a combined two-passage skid control valve, and has differential pressure limiting valves 7, 20, 21.
The skid control device according to claim 1, wherein the skid control valve (6) is integrated into the casing of the skid control valve (6). 3. The skid control device according to claim 1, wherein the differential pressure limiting valves 20, 21 are provided outside the skid control valve 6. 4. The skid according to claim 1, wherein the differential pressure limiting valve 21 has a common valve spring 22 for the two overflow valves and is selectively arranged inside or outside the skid control valve. Tudo control device.