JPS6318539B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an anti-skid device for braking the wheels of an automobile, which commonly controls the braking pressure in the brake cylinders of one axle. A common three-port two-position directional control valve is inserted in the communicating conduit and a pressure-holding valve is inserted in each branch line.

BACKGROUND OF THE INVENTION An antiskid device of this type is known (German Patent Application No. 2 655 951).

In known antiskid devices of this kind, all valve passages in the valve arrangement are normally open during braking and during braking release, so that the braking medium can flow unhindered to the brake cylinder and from the brake cylinder to the brake valve.

When the antilock is activated, the three-port, two-position directional control valve interrupts the connection to the brake valve, thereby interrupting any subsequent braking pressure build-up. On the other hand, the valve already mentioned opens the outside air connection line of the brake cylinder, so that the braking pressure in the brake cylinder is reduced. If both wheel brakes are to be antilocked, the braking pressure medium can be discharged from both brake cylinders to the outside via a 3/2-way directional control valve. For this purpose, the cross-section of a common fresh air connection is determined in such a way that, for example, a slight residual pressure is created in the brake cylinder within 0.2 seconds.

If only one wheel brake cylinder is at risk of locking, the holding valve of the other brake cylinder is switched to pressure holding and the braking pressure medium is switched to the first wheel brake cylinder.
is emitted only from the brake cylinder. This small amount of pressure medium of the 3/2-way directional control valve is discharged through the same outlet cross-section of the common 1 fresh air connection line already mentioned, so that the discharge is e.g.
This is done in an extremely short time of 0.1 seconds. However, when antilocking one wheel brake,
If the pressure drop times differ in this way when both wheel brakes are antilocked, since the switching times of the front control valve and the main valve are constant, the degree of pressure drop in the brake cylinder will be different in both cases. This is truly inconvenient.

Problems to be Solved by the Present Invention The problem to be solved by the present invention is to make the time required for discharging the brake medium constant when the brakes are anti-locked on one wheel and when both wheel brakes are anti-locked. It's about doing.

Means for Solving the Problems The gist of the present invention that solves the above problems is that a slide is provided to change the cross section of the outside air connection pipe for outflowing braking air when switching the 3-port 2-position directional control valve. and the slide is formed as a sleeve, and two of its outer walls are
Each branch line 20, 21 has two mutually opposite lateral parts leading to a brake cylinder.
The reason lies in the fact that it is designed to penetrate inside and change its cross section.

Effects and Effects of the Invention According to the invention, the slide for changing the external air connection conduit projects with its side portion into each branch conduit leading to each brake cylinder and changes its cross section. Therefore, the same degree of pressure drop can be obtained in the same amount of time whether exhausting air from both wheel brakes or from one wheel brake.
The disadvantages already mentioned are avoided. If the above conditions are met, the pressure drop time is about 0.18 seconds whether only one brake cylinder is antilocked or two brake cylinders are antilocked. Further advantages of the present invention include:
The cross section of the valve arrangement has been designed to suit the maximum actuator volume, so that when relatively small brake cylinders are used, the valve arrangement can be easily adapted by means of a separate valve insert and can accommodate one or two brake cylinders. The anti-skid device can be adapted to the actuator volume so that the pressure in the brake cylinder is reduced to a substantially uniform pressure level regardless of whether the brake cylinder is vented or not.

It is furthermore advantageous that when the three/two-way directional control valve is not actuated, i.e. during normal braking, the entire cross-sectional area within the valve arrangement is maintained.

Embodiments Next, the present invention will be specifically explained with reference to illustrated embodiments.

A pressurized air storage container 1 is connected to a brake valve 2, which supplies the two brake cylinders 3, 4 with pressure. Both brake cylinders 3, 4 are connected to two axles 5, 6 arranged on one axle 7.
The wheel brakes of the wheels 5 and 6 are operated, and the rotational speed of the wheels 5 and 6 is monitored by a sensor (not shown). Three pre-control solenoid valves 11, 12, 13 are arranged in the brake conduits 8, 9, 10 leading from the brake valve 2 to the brake cylinders 3, 4, and these solenoid valves are respectively connected to the main valve 17, 18 or to the brake cylinder 3, 4. The connecting passages 14, 15, and 16 to 19 are controlled.

The central main valve 18 is connected directly to the brake line 8 and thereby to the brake valve 2 . This main valve 18 is designed as a 3-port, 2-position directional control valve, and further main valves 1 on both sides are designed as 2-port, 2-position directional control valves.
The branch pipes 20 and 21 leading to the pipes 7 and 19 are controlled. The main valves 17, 19 may be referred to below as holding valves.

The pre-control solenoid valves 11, 12, 13 and the main valves 17, 18 and 19 are combined as a valve device 22. This valve device 22 is provided with three valve seats 23, 24, 25 in parallel with each other, and the flow between the valve seats 23, 24, 25 is controlled by the valve closing members 26, 25.
7 and 28.

The connecting passages 14, 15, 16 leading to the pre-control solenoid valves 11, 12, 13 are connected to the working chambers 29, 30,
31, and the working chambers 29, 30, 31
Two of the working chambers 29 and 31 contain the valve closing member 2.
6,28. The working chamber 30 is delimited by a diaphragm 34.

A brake conduit 8 is connected to the valve inlet 32, and the valve inlet 32 is connected to a 3-port 2-position directional control valve 18.
A rod 33 passing through the valve seat 24 is fixed to the valve closing member 27 of this three-port, two-position directional control valve. The rod 33 has a diaphragm 34 at its lower end as a pressure-side working part. The valve closing member 27 forms, together with the valve seat 24 fixed to the casing, the outlet valve 24/27 of the three-port, two-position directional control valve 18 which controls the outside air connection line 36 and is provided at the valve inlet 32. Valve seat 3
2' together form an inlet valve 32'/27.

The valve closing member 27 further includes a sleeve-like slide 40, which has a bottom 41 with a hole. The slide 40 is the bottom 4
1 coaxially fixed to the valve closing member 27. The slide 40, by means of two mutually opposed lateral parts 42, 43 of the outer wall, projects into the branch line 20, 21, as shown in broken lines, and changes the flow cross section of this line.

This device operates as follows.

During normal braking and braking release, brake valve 2
A free conduit is formed from the brake cylinders 3, 4 via the brake conduits 8, 9, 10 to the brake cylinders 3, 4.
In this case, the brake air reaches the brake cylinders 3, 4 via the 3-port, 2-position directional control valve 18, the branch lines 20, 21 and the two 2-port, 2-position directional control valves 17, 19.

If a wheel, for example wheel 6, is excessively braked by brake cylinder 4, the anti-skid mechanism is activated and pre-control solenoid valves 11, 12 are switched. This makes the 3-port 2-position directional control valve 1
8 is turned off and air flows out from the brake cylinder 4 to the outside air. At the same time, the two-port, two-position directional control valve 17 is switched to the closed position, thereby maintaining the pressure in the non-locking brake cylinder 3. At the end of the pressure drop in the brake cylinder 4 all pre-controlled solenoid valves 11, 12, 1
3 can be switched. 3 port 2 position directional control valve 1
The 8- and 2-port 2-position directional control valves 17 are shut off and the 2-port 2-position directional control valve 19 is switched to the closed position, thereby maintaining a reduced braking pressure in the brake cylinder 4. After some time, at the end of this holding operation, the precontrol solenoid valve 13 is again shut off, so that the holding valve 19 is returned to its starting position for increasing the pressure. The reduced braking pressure in the brake cylinder 4 is increased again in a pulsating manner by opening and closing the pre-control solenoid valve 13.

The key point in this case is that the braking pressure reduction and braking pressure formation of the two brake cylinders 3 and 4 are
implemented via the port 2 position directional control valve 18;
and by this. A common braking pressure modulation due to the loading and unloading of the brake cylinders 3, 4 is achieved at any time by means of a 2-port 2-position directional control valve 17, 1 connected in series to each brake cylinder.
9 to be interrupted separately. Therefore, by controlling both brake cylinders 3, 4 together or only one of them, although one valve is saved compared to a system that antilock-controls each wheel separately. A sufficient degree of anti-lock control can be achieved.

During anti-lock pressure reduction, the three-port, two-position directional control valve 18 is switched such that the closing member 24 closes the valve inlet 32 and opens the valve seat leading to the outside air connection line 36. The slide 40 then projects into the branch lines 20, 21 and reduces their cross section. Since both holding valves 17, 19 are open, pressure medium is discharged from the brake cylinders 3, 4 via branch lines 20, 21, each of which has a reduced cross section. If only one of the holding valves 17 or 19 is open, the pressure medium is likewise discharged from the associated brake cylinder via the branch line 20 or 21. By reducing the cross section of each branch line 20, 21 in this way, the pressure drop time becomes exactly the same in both cases due to its throttling effect.

By using slides 40 of different heights to vary the depth of penetration, the anti-skid device can be easily adapted to the actuator volume. In that case, the valve arrangement can be designed to accommodate the maximum actuator volume, so that it can be easily replaced with a slide 40 of a different length if a small brake cylinder is used.

The element for changing the outflow cross section may also be formed from a separate throttling device. Furthermore, it is also possible to control this element by means of an electrical switching element.

[Brief explanation of the drawing]

The drawing is a schematic cross-sectional view of one embodiment of the invention. 1... Pressure air storage container, 2... Brake valve, 3,
4... Brake cylinder, 5, 6... Wheel, 7... Axle, 8, 9, 10... Brake conduit, 11, 12,
13... Front control valve, 14, 15, 16... Connection passage,
17, 18, 19... Main valve, 20, 21... Branch pipe line, 22... Valve device, 23, 24, 25... Valve seat, 2
6, 27, 28... Valve closing member, 29, 30, 31
...Working chamber, 32...Valve inlet, 32'...Valve seat, 33...
Rod, 34...Diaphragm, 36...Outside air connection pipe,
40...Slide, 41...Bottom, 42, 43...Side portion.

Claims (1)

[Scope of Claims] 1. An anti-skid device for braking the wheels of an automobile, which commonly controls the braking pressure in the brake cylinders of one axle, the antiskid device having a common brake pressure in the brake conduit leading to both brake cylinders. In a type with one 3-port 2-position directional control valve and a pressure holding valve inserted in each branch pipe, the brake air that flows out when the 3-port 2-position directional control valve 18 is switched is outside air connection pipe 36
A slide 40 is provided which changes the cross section of the brake cylinder 3, and the slide 40 is designed as a sleeve and the two mutually opposed lateral parts 42, 43 of its outer wall are connected to the brake cylinder 3, Respective branch pipes 20, 2 leading to 4
1. An anti-skid device characterized in that the cross section of the anti-skid device changes by entering the inside of the anti-skid device. 2. An anti-skid device according to claim 1, wherein said slide (40) is connected to a valve closing member (27) of a three-port, two-position directional control valve (18). 3. The slide 40 for changing the cross section of the outside air connecting pipe of the branch pipes 20, 21, which is controlled by the valve closing member 27, is supported by the valve closing member 27. Anti skid device. 4. A bottom part 41 in which the slide 40 is arranged coaxially with respect to the valve closing member 27 of the three-port two-position valve 18 and is provided with a hole as an air passage to the outside.
5. An anti-skid device according to claim 4, characterized in that the slide (40) is fixed to the valve closing member (27) by means of its bottom.