EP3877226A1

EP3877226A1 - Valve assembly and pressure control method

Info

Publication number: EP3877226A1
Application number: EP19794446.5A
Authority: EP
Inventors: René Jonkmann; Alexander Krumrey; Andreas König
Original assignee: Knorr Bremse Systeme fuer Nutzfahrzeuge GmbH
Current assignee: Knorr Bremse Systeme fuer Nutzfahrzeuge GmbH
Priority date: 2018-11-07
Filing date: 2019-10-17
Publication date: 2021-09-15
Also published as: BR112021008372A2; JP2022506698A; WO2020094362A1; DE102018127822A1; CN113286730A; US20210402971A1; JP7203967B2

Abstract

The invention relates to a valve assembly for pressure control on an output port (P2). The valve assembly comprises an inlet port (P1), a pressure sink (S), a first valve (110) having a first control connection (112), and a second valve (120) having a second control connection (122), which are arranged in series between the inlet port (P1) and a pressure sink (S) and between which the outlet port (P2) branches off. The valve assembly also comprises a first control valve (115), which controllably connects the first control connection (112) to the inlet port (P1) or vents same, and a second control valve (125), which controllably connects the second control connection (122) to the outlet port (P2) or vents same.

Description

DESCRIPTION

Valve arrangement and a method for pressure control

The present invention relates to a valve arrangement and a method for pressure control at an output port, in particular to a valve arrangement with an optimized air flow to increase its service life.

In the case of anti-lock braking systems (ABS) of pneumatic brake systems for commercial vehicles, the air pressure is temporarily reduced considerably during an ABS intervention in order to release the wheels from locking or to release the brake briefly. These pressure drops are implemented, for example, by an outlet valve, a diaphragm in the outlet valve in the current design being considerably stressed by this brief pressure drop (s), which at the same time limits the service life of the valve arrangement.

3A and 3B show an example of such a conventional valve arrangement that is used for ABS pressure control, FIG. 3A showing a circuit diagram and FIG. 3B showing an exemplary implementation of the valve arrangement.

In the valve arrangement of FIG. 3A, a first valve 10 and a second valve 20 are arranged in series between an input port P1 and a pressure sink S. The first valve 10 includes a control input 12, which is connected to a first control valve 15. The first control valve 15 connects the control connection 12 of the first valve 10 either to the pressure sink S or to the input port P1. The second valve 20 also includes a control input 22, which is controlled via a second control valve 25. The second control valve 25 connects the control connection 22 of the second valve 20 either to the pressure sink S or also to the input port P1. In the valve arrangement shown, a control pressure line 40 is formed between the input port P1 and the second control valve 25, so that the pressure from the input port P1 is provided as control pressure at the control input 22. FIG. 3B shows a possible concrete implementation of the circuit from FIG.

3A. All pressure sinks S are connected here to a ventilation port P3, which is connected, for example, to an external environment. The first valve 10 comprises a first membrane 13 and the second valve 20 a second membrane 23. The first membrane 13 opens and / or closes the connection between the input port P1 and the output port P2, depending on a pressure at the

Control port 12. When the control port 12 is vented, the first valve 10 closes, when the control port 12 is vented, the first valve 10 opens. The second diaphragm 23 opens and / or closes the connection between the output port P2 and the pressure sink S, and depending on a pressure on the

Control port 22. When the control port 22 is vented, the second valve 20 closes; when the control port 22 is vented, the second valve 20 opens. As shown schematically in FIG. 3A, the drive pressure line 40 is as a channel between the input ports P1 and the second control valve 25 is formed.

The first control valve 15 is pretensioned in such a way that it ventilates the control connection 12 of the first valve 20 in the de-energized state. Therefore, the first valve 10 will open automatically when a positive pressure is applied to the input port P1. The second control valve 25 is pretensioned in such a way that in the de-energized state it forwards the compressed air at the input port P1 via the control pressure line 40 to the control connection 22 of the second valve 20. Therefore, on the back of the second diaphragm 23, when the second control valve 25 is not activated, the pressure of the latter is continuously present

Input port P1 on.

In the (default) position shown, the pressure of the input port P1 is forwarded to the output port P2 via the opened first valve 10. However, if an ABS intervention is to be carried out and the pressure at the outlet port P2 is to be briefly reduced, this is done by opening the second valve 20. This connects the outlet port P2 to the pressure sink S (P3). This can be done by energizing the second control valve 25, which causes the control port 22 to be vented. A new venting of the control port 22 using the second control valve 25 increases the pressure at the control port 22 to the pressure from the input port P1 and thus to close the second valve 20. As the pressure at the inlet port P1 is often significantly higher than the pressure at the outlet port P2 when the ABS is activated, this led to a considerable one

Load on the second membrane 23, which separates the two pressures from one another.

This significantly shortens the life of the entire valve assembly. It is usually not economically sensible to replace a single membrane.

Therefore, there is a need for valve assemblies that enable fast and efficient pressure control on an output port, but still a long one

Ensures the service life of the valves used. This is particularly important for autonomous driving, since the components used there are constantly of a high standard

Are exposed to stress and a significantly longer lifespan

Valve control device is desirable.

At least part of the above-mentioned problems are solved by a valve arrangement according to claim 1 and a method for pressure control according to claim 9. The dependent claims define further advantageous embodiments of the

Objects of the independent claims.

Exemplary embodiments relate to a valve arrangement for pressure control at an output port. The valve assembly includes an input port, a

Pressure sink, a first valve with a first control connection and a second valve with a second control connection, which are arranged in series between the input port and the pressure sink and between which the output port branches. The valve arrangement further comprises a first control valve that controllably connects or ventilates the first control port to the input port and a second control valve that controllably connects or ventilates the first control port to the output port.

Optionally, the first control valve is a solenoid valve, which ventilates the first control connection when de-energized. The second control valve can also be a

Be solenoid valve, with the solenoid valve the second in the de-energized state

Control port connects to the output port. Optionally, the first valve comprises a first membrane, which opens or closes a connection between the input port and the output port when the first valve is actuated. Likewise, the second valve can comprise a second membrane which, when the second valve is actuated, connects between the

Output port and the pressure sink opens or closes.

The first diaphragm is optionally pre-stressed (e.g. by a spring) in order to close the first valve when the inlet port is depressurized. The second is optional

Diaphragm preloaded (e.g. by another spring) in order to close the second valve at the outlet port when there is no pressure.

The valve arrangement optionally includes a throttle in order to limit an inflow (e.g. in air) via the inlet port.

Embodiments also relate to an anti-lock braking system for a

Vehicle brake, especially for commercial vehicles, that a previously defined

Has valve arrangement for pressure control at the output port, the

Output port with a brake cylinder (a brake of the vehicle) is connectable.

Optionally, an ABS intervention can vent the output port through the second valve and thus briefly release the brake.

Exemplary embodiments also relate to a commercial vehicle with a

Valve arrangement as previously defined or with an anti-lock braking system as previously defined.

Exemplary embodiments also relate to a method for controlling a pressure at an output port by means of a valve device as previously defined. The process includes:

- supplying a pressure via the inlet port through a first valve to an outlet port;

- closing the first valve to maintain the pressure at the outlet port; - Connection of the output port to a pressure sink through a second valve in order to lower the pressure at the output port (e.g. briefly, suddenly); and

- Interruption of the connection of the output port to the pressure sink by activating the second valve with the pressure at the output port.

In contrast to conventional valve arrangements for pressure control, in which the control of the two diaphragms is carried out with unregulated pressure as standard (see FIGS. 3A and 3B), the air supply is changed by

Embodiments lowered the load on the second membrane (outlet membrane) to a level of the first membrane (holding membrane). This results in a significantly longer service life for the entire module. Basically, the

The outlet membrane is no longer significantly more stressed than the inlet membrane. Cracks in the outlet diaphragm can be avoided by lowering the control pressure or only appear significantly later.

Embodiments of the present invention will be better understood from the following detailed description and the accompanying drawings of FIG

different exemplary embodiments, which, however, should not be understood in such a way that they restrict the disclosure to the specific embodiments, but only serve for explanation and understanding.

1 shows a circuit diagram of a valve arrangement for pressure control according to a

Embodiment of the present invention.

FIG. 2 shows a possible implementation of the valve arrangement from FIG. 1.

3A shows a circuit diagram of a conventional valve arrangement.

3B shows an implementation of the conventional valve arrangement.

1 shows a circuit diagram for a valve arrangement for pressure control according to an exemplary embodiment of the present invention. As in the conventional

3A are arranged in series between an input port P1 and a pressure sink S, a first valve 110 (for example a holding valve) and a second valve 120 (for example an outlet valve). The pressure sink S can or have multiple openings to an environment or comprise one or more areas with reduced pressure. The first valve 110 includes one

Control input 112, which is connected to a first control valve 115. The first control valve 115 connects the control port 112 of the first valve 110 either to the pressure sink S or to the input port P1. The second valve 120 also includes a control input 122 which is controlled via a second control valve 125. The second control valve 125 connects the control port 122 of the second valve 120 either to the pressure sink S or to the output port P2. The dashed lines are intended to indicate a possible guidance of the first valve 110 and / or the second valve 120 when the valve is confirmed.

In contrast to the conventional valve arrangement from FIG. 3A, at

Embodiments a drive pressure line 140 available, the

Output port P2 connects to the second control valve 125, so that the control pressure at the control input 22 is provided by the output port P2 and not by the input port P1.

The first control valve 115 and / or the second control valve 125 is / are, for example, a pre-loaded solenoid valve (s) that are in a de-energized state

Show preferred position. The first control valve 115 thus connects the control port 112 of the first valve 110 to the pressure sink S in the de-energized state and to the input port P1 in the energized state (activated state). The second

Control valve 25 connects the control port 122 of the second valve 120 to the output port P2 in the de-energized state and to the pressure sink S in the activated state.

In this way, a pressure at the input port P1 is passed through the first valve 110 to the output port P2 (for example when the brake is actuated). This connection can be specifically interrupted or held by switching the first valve 110 through the control valve 115. In addition, the pressure at the output port P2 is passed through the second control valve 125 to the control port 122 of the second valve 120. As long as the second control valve 125 is not actuated, the connection between the output port P2 and the pressure sink S remains interrupted and the brake pressure is maintained. If the exemplary ABS is activated, the pressure at the output port P2 is to be significantly reduced, at least temporarily. This is achieved by activating the second control valve 125 (it is energized), so that the control connection 122 on the second valve 120 is vented. This causes the outlet port P2 to be vented by opening the connection to the pressure sink S through the second valve 120.

FIG. 2 shows a possible concrete implementation of the circuit from FIG. 1, which in turn is similar to the implementation from FIG. 3A. Here too, all pressure sinks S are connected to a vent port P3, which in turn can be connected to an external environment. As with the conventional

In implementation, the first valve 110 includes a first diaphragm 113 and the second valve 120 includes a second diaphragm 123. In addition, the one shown includes

Implementation of an optional throttle 105 to limit the flow rate through the valve assembly to a desired value.

The first membrane 113 opens and / or closes the connection between the

Input port P1 and output port P2, depending on a pressure at the control port 112 of the first valve 110. When the control port 112 of the first valve 110 is vented, the first valve 110 closes when the

Control port 112 is vented, the first valve 110 opens.

The second diaphragm 123 opens and / or closes the connection between the output port P2 and the pressure sink S, depending on a pressure at the control port 122 of the second valve 120. When the control port 122 is vented, the second valve 120 closes when the control connection 122 is vented, the second valve 120 opens the connection to the pressure sink S.

All other components can be designed in the same way as in the conventional valve arrangement from FIGS. 3A and 3B.

In contrast to the conventional implementation from FIG. 3A, however, the drive pressure line 140 is between the output port P2 and the second control valve 125 and the pressure at the output port P2 is used as a control pressure for venting the second valve 20 - and not, as in the conventional arrangement, the pressure from the input port P1.

The first control valve 115 is pretensioned by means of a spring, for example, in such a way that it ventilates the control connection 112 of the first valve 110 in the currentless state. Therefore, the first valve 110 will automatically open when a positive pressure is applied to the input port P1. The second control valve 125 is also biased by means of a spring in such a way that, when de-energized, the compressed air is above the

Control pressure line 140 forwards to the control port 122 of the second valve 120. Therefore, the pressure from the output port P2 is continuously applied to the back of the second membrane 123.

If the exemplary anti-lock braking system is to intervene (the pressure at the output port P2 is to be briefly or pulsedly reduced, for example), this is done by opening the second valve 120, whereby the output port P2 is connected to the pressure sink S (P3). In addition, the second control valve 125 is briefly energized, which causes the control connection 122 to be vented, so that the second diaphragm 122 opens the opening to the pressure sink S.

A new venting of the control port 122 by de-energizing the second control valve 125 increases the pressure at the control port 122 to the pressure from the output port P2. The same pressures are then present on both sides of the second membrane 123. However, since the second diaphragm 123 is prestressed (e.g. via a spring), the second diaphragm 123 closes the opening in this case

Pressure sink S. Here, the second membrane 123 closes an opening to a flow channel located above, which is connected via a funnel-shaped structure to the pressure sink S at the vent port P3 (shown only schematically in FIG. 2, since the connection is located outside the drawing plane).

It goes without saying that the pressures and also the channel guides can be chosen arbitrarily and the invention should not be restricted to certain pressure conditions or channel guides. However, one advantage of exemplary embodiments is precisely that - regardless of the pressures present - on both sides of the second membrane 123

There are (almost) the same pressures, namely the pressure from the output port P2.

This significantly reduces the load on the second membrane 123 and extends the service life. There is a significantly lower load or lower stresses in the material and therefore less damage to the components.

The features of the invention disclosed in the description, the claims and the figures can be used both individually and in any combination for the

Realization of the invention may be essential.

REFERENCE SIGN LIST

10, 1 10 first valve

12, 112 control connection of the first valve 13, 113 first membrane

15, 115 first control valve

20, 120 second valve

22, 122 control connection of the second valve 23, 123 second membrane

25, 125 second control valve

40, 140 control pressure lines

P1 input port

P2 output port

S, P3 pressure sink / vent port

Claims

PATENT CLAIMS

1. Valve arrangement for pressure control at an output port (P2) with an input port (P1), a pressure sink (S), a first valve (110) with a first control connection (112) and a second valve (120) with a second

Control connection (122), which are arranged in series between the input port (P1) and the pressure sink (S) and between which the output port (P2) branches,

marked by

a first control valve (115) controllably connecting or venting the first control port (112) to the input port (P1); and

a second control valve (125) which controllably connects or vents the first control connection (122) to the output port (P2).

2. Valve arrangement according to claim 1,

characterized in that

the first control valve (115) is a solenoid valve which, when de-energized, vents the first control connection (112); and

the second control valve (125) is a solenoid valve which, when de-energized, connects the second control connection (122) to the output port (P2).

3. Valve arrangement according to claim 1 or claim 2,

characterized in that

the first valve (110) comprises a first membrane (113) which, when the first valve (110) is actuated, connects between the input port (P1) and the

Output port (P2) opens or closes; and or

the second valve (120) comprises a second membrane (123), which opens or closes a connection between the output port (P2) and the pressure sink (S) when the second valve (120) is actuated.

4. Valve arrangement according to claim 3,

characterized in that

the first membrane (113) is biased to close the first valve (110) in the unpressurized case at the inlet port (P1); and or the second membrane (123) is biased to close the second valve (110) at the outlet port (P2) in the unpressurized case.

5. Valve arrangement according to one of the preceding claims,

marked by

a throttle (105) that limit an inflow through the input port (P1).

6. anti-lock braking system for a vehicle brake,

marked by

a valve arrangement according to one of the preceding claims for pressure control at the output port (P2), the output port (P2) being connectable to a brake cylinder of a brake of the vehicle.

7. anti-lock braking system (ABS) according to claim 6,

characterized in that

an ABS intervention causes the output port (P2) to be vented through the second valve (120) and thus briefly releases the brake.

8. commercial vehicle,

marked by

a valve arrangement according to one of claims 1 to 5; or

an anti-lock braking system according to claim 6 or claim 7.

9. A method for controlling a pressure at an output port (P2) by means of a valve device according to one of claims 1 -5,

marked by

- supplying a pressure via the input port (P1) through a first valve (110) to an output port (P2);

- Closing the first valve (110) to increase the pressure at the outlet port (P2)

hold;

- Connecting the output port (P2) to a pressure sink (S) through a second valve (120) in order to lower the pressure at the output port (P2); and - Interrupting the connection of the output port (P2) to the pressure sink (S) by activating the second valve (120) with the pressure at the output port (P2).