DE102020108758A1 - Compressed air supply system for operating a pneumatic system, compressed air supply system with the compressed air supply system, and vehicle with the compressed air supply system and methods for operating the compressed air supply system - Google Patents

Abstract

The invention relates to a compressed air supply system (10, 10 ', 10 ") for operating a pneumatic system (100), comprising: a compressed air supply (1), a compressed air connection (2) to a pneumatic system (90) and a ventilation connection (3) for Environment, - a main pneumatic line (5) between the compressed air supply (1) and the compressed air connection (2), in which an air dryer (60) is connected, and - a ventilation line (6) to the ventilation connection (3), which runs between the compressed air supply ( 1) and the air dryer (60) is connected to the main pneumatic line (5), a vent valve (124) connected via a first and a second vent valve connection (124X, 124Y) being connected in the vent line (6), - a control pressure path (7 ) with a control valve (126) connected in the control pressure path (7) as part of a vent valve arrangement with the control valve (126) and the vent valve (124), wherein- the vent valve valve (124) is formed as a relay valve with a control connection (124.1), which is pneumatically connected to the control valve (126) via the control pressure path (7) to act on the control connection (124.1) with a control pressure which can be branched via the control pressure path (7) ( According to the invention, it is provided that the control pressure (p) can be fed via the control pressure path (7) on both sides of the vent valve (124), namely by means of the control valve (126) to the control port (124.1) and without interruption to the control counter port (124.2) of the vent valve (124) ) can be supplied.

Description

The invention relates to a compressed air supply system according to the preamble of claim 1 and a corresponding pneumatic compressed air supply system and vehicle with a compressed air supply system and a pneumatic system. The invention also relates to a method for operating a compressed air supply system or the pneumatic compressed air supply system.

Air dryer arrangements, in particular air dryer arrangements in compressed air supply systems for providing compressed air for pneumatic systems such as, for example, air suspension systems for vehicles, are generally known. A compressed air supply system of a general type is used in vehicles, in particular for supplying an air suspension system of a vehicle with compressed air. Air suspension systems can also include level control devices with which the distance between the vehicle axle and the vehicle body can be adjusted. An air suspension system of a pneumatic system mentioned at the beginning comprises a number of air bellows pneumatically connected to a common line (gallery), which can raise the vehicle body with increasing filling and lower it accordingly with decreasing filling. As the distance between the vehicle axis and the vehicle body or ground clearance increases, the spring travel becomes longer and larger uneven floors can be overcome without coming into contact with the vehicle body. Such systems are used in off-road vehicles and sport utility vehicles (SUV). In the case of SUVs in particular, with very powerful engines, it is desirable on the one hand to provide the vehicle with a comparatively low ground clearance for high speeds on the road and on the other hand to provide the vehicle with a comparatively large ground clearance for the terrain. It is also desirable to change the ground clearance as quickly as possible, which increases the requirements with regard to speed, flexibility and reliability of a compressed air supply system.

A compressed air supply system for use in a pneumatic system with a pneumatic system, for example an air suspension system described above, is operated with compressed air from a compressed air supply, for example at a pressure level of 5 to 20 bar. The compressed air is made available to the compressed air supply with an air compressor. The compressed air supply is pneumatically connected to a compressed air connection to supply the pneumatic system and, on the other hand, pneumatically connected to a ventilation connection. The compressed air supply system can be vented to the vent connection via a vent valve arrangement by releasing air.

Air dryer arrangements for compressed air supply systems for providing dry compressed air are used to ensure long-term operation of the compressed air supply system; this has an air dryer with which the compressed air is to be dried. This avoids the accumulation of moisture in the pneumatic system, which can lead to valve-damaging crystal formation at comparatively low temperatures and otherwise can lead to undesired defects in the compressed air supply system and in the pneumatic system, such as frozen lines or valves. An air dryer has a desiccant, usually a granulate bed, through which the compressed air can flow, so that the granulate bed can absorb moisture contained in the compressed air by adsorption - at a comparatively high pressure.

An air dryer can be designed as a regenerative air dryer - especially for a compressed air supply system for a pneumatic system comprising an air suspension system. This can be done in that the granulate bed is flowed through with the dried compressed air from the air suspension system in countercurrent or cocurrent relative to the filling direction during each deaeration cycle - at a comparatively low pressure. For this purpose, the vent valve arrangement can be opened. For such an application - also referred to as pressure swing adsorption - it has proven to be desirable to design a compressed air supply system flexibly and at the same time reliably, in particular to enable comparatively fast ventilation with a pressure change that is nevertheless sufficient for a regeneration of the air dryer. Avoiding moisture in the pneumatic system and in particular in the compressed air supply system under the stated boundary conditions is therefore still problematic. In particular, this relates to an effective regeneration of the air dryer.

It is therefore desirable to reduce moisture in a pneumatic system and in particular in a compressed air supply system and, in particular, to ensure effective regeneration - and that the air dryer can be regenerated over a long period of time.

• - eine Pneumatikhauptleitung zwischen der Druckluftzuführung und dem Druckluftanschluss, in welcher ein Lufttrockner angeschlossen ist, und
• - eine Entlüftungsleitung zu dem Entlüftungsanschluss, die zwischen der Druckluftzuführung und dem Lufttrockner an die Pneumatikhauptleitung angeschlossen ist, wobei in der Entlüftungsleitung ein über einen ersten und einen zweiten Entlüftungsventilanschluss angeschlossenes Entlüftungsventil angeschlossen ist,
• - einen Steuerdruckpfad mit einem im Steuerdruckpfad angeschlossenen Steuerventil als Teil einer Entlüftungsventilanordnung mit dem Steuerventil und dem Entlüftungsventil, wobei
• - das Entlüftungsventil als ein Relaisventil mit einem Steueranschluss gebildet ist, der über den Steuerdruckpfad mit dem Steuerventil pneumatisch verbunden ist zur Beaufschlagung des Steueranschlusses mit einem über den Steuerdruckpfad abzweigbaren Steuerdruck.

In the present case, the compressed air supply system is designed to operate a pneumatic system or a pneumatic system and has a compressed air supply, a compressed air connection to the pneumatic system and a ventilation connection to the environment. The compressed air supply system also has:

• - a main pneumatic line between the compressed air supply and the compressed air connection, in which an air dryer is connected, and
• - A vent line to the vent connection, which is connected to the main pneumatic line between the compressed air supply and the air dryer, a vent valve connected via a first and a second vent valve connection being connected in the vent line,
• - A control pressure path with a control valve connected in the control pressure path as part of a vent valve arrangement with the control valve and the vent valve, wherein
• - The vent valve is formed as a relay valve with a control connection which is pneumatically connected to the control valve via the control pressure path in order to act on the control connection with a control pressure that can be branched off via the control pressure path.

Such a compressed air supply system with a vent valve arrangement, which in the present case is referred to as a “rapidly ventilating, indirectly pilot-controlled arrangement”, is also shown in FIG DE 10 2012 001 736 A1 described. There, too, the vent valve has a control connection which is pneumatically connected to a control valve via a control pressure path; this control pressure path is connected to a single main branch connection on the main pneumatic line; such a "rapidly venting, indirectly pilot-operated arrangement" is described; in the present application in 1 B. .

In DE 10 2014 009 419 is according to paragraphs [0064] and [0068] to that shown therein 1B explains how a purely pneumatic control of the vent valve according to the concept of a compressor-controlled venting functionality can be implemented in a device in the present application in 1A explained in more detail, commonly referred to as “direct-venting arrangement” of a venting valve arrangement. The vent valve can be acted upon pneumatically on both sides and is part of a vent valve arrangement in the form of a controllable normally closed solenoid valve for venting air via the vent line 3 ' to the vent connection, which in addition to the vent valve also has a check valve arranged in a control line.

In WO2016 / 026577 is to 8th ff on page 30/31 explains how, in what is commonly referred to as "normally ventilating, pilot-operated arrangement", an additional vent line as a feedback line is connected to a vent back chamber of a vent valve, which thus pneumatically connects the second control port to the vent port of the vent valve via the vent back chamber. As a result, the second control connection can be designed to receive a second control part pressure on the relay piston extension which acts in addition to a first control part pressure of the first control connection. The second control connection on the relay piston extension is thus designed as a counter control connection for receiving the second control part pressure, which acts in addition to the first control part pressure of the first control connection. This control part pressure is in particular throttled and limited in time and acts on the relay piston extension in the opposite direction to the first control part pressure of the first control connection on the relay piston. In other words, the control pressure, but in any case a control pressure derived therefrom, is applied to the first and second control surface of the relay piston extension and thus also with an effect on the relay piston when the control valve is switched. For this purpose, a throttle in the further vent line to the vent back space can be designed with a comparatively small nominal width; Among other things, this can dampen the movement of a relay piston in the context of such a normally ventilating, pilot-operated arrangement ”. It is desirable to find an adequate solution for a “rapidly venting, indirectly pilot-operated arrangement” - in the present application in 1B - to find that reduces moisture in a pneumatic system and in particular a compressed air supply system and ensures effective regeneration - and long-term regenerability - of the air dryer. In particular, it is desirable to specify a compressed air supply system and corresponding devices and methods which have a vent valve arrangement as a "rapidly ventilating, indirectly piloted arrangement" and which has an air dryer arrangement by means of which moisture in a pneumatic system can be reduced and with a more effective regeneration of the air dryer .

• - in einem ersten Schaltzustand der erste und zweite Entlüftungsventil-Anschluss pneumatisch getrennt und
• - in einem zweiten Schaltzustand der erste und zweite Entlüftungsventil-Anschluss pneumatisch verbunden sind, wobei

der Relaiskolben unter Beaufschlagung des ersten Steueranschlusses mit Steuerdruck betätigbar ist, und wobei das Entlüftungsventil weiter einen Entlüftungsrückraum mit einem Entlüftungsanschluss aufweist, an welchen eine noch weitere Entlüftungsleitung zur Entlüftung des Entlüftungsrückraums bei Betätigung des Relaiskolbens angeschlossen ist. DE 10 2014 012 608 A1 relates to a "fast-venting, indirectly pilot-operated arrangement", which is related to a there in 1 compressed air supply system shown is described, for operating a pneumatic system, comprising: a compressor for generating compressed air for a compressed air supply; the compressed air supply, a compressed air connection to the pneumatic system and a ventilation connection to the environment; a main pneumatic line between the compressed air supply and the compressed air connection; between the compressed air connection and the ventilation connection, a ventilation line with a ventilation valve connected via a first and a second ventilation valve connection, which also has a first control connection in pneumatic connection with a control valve having, the pneumatic connection being formed as a pneumatic control line which can be acted upon by control pressure with a relay piston control line, the vent valve having a relay piston and

• - In a first switching state, the first and second vent valve connection are pneumatically separated and
• - In a second switching state, the first and second vent valve connection are pneumatically connected, wherein

the relay piston can be actuated by applying control pressure to the first control connection, and wherein the vent valve further has a vent return chamber with a vent connection to which a further vent line for venting the vent return chamber is connected when the relay piston is actuated.

In particular, a comparatively fast venting with a comparatively increased vent valve nominal width is also desirable, without the outlay for actuating the vent valve with a solenoid control valve becoming too great; that is, the effort involved in a magnetic part of a control valve arrangement for controlling a pneumatic part of the control valve arrangement becomes too great. At the same time, any residual pressure remaining in the system should be kept as low as possible in order to keep a risk associated with moisture or icing for the compressed air supply system, in particular the valves of the vent valve arrangement, low, and a measure to avoid the risk of icing is also desirable.

The problem at this point is that, on the one hand, rapid venting can be achieved with comparatively large nominal widths of a vent valve; On the other hand, however, this regularly makes a comparatively large magnet necessary for actuating the pneumatic part of the vent valve or the vent valve arrangement in the previously known compressed air supply systems, d. H. a comparatively large magnet of the magnetic part of the control valve arrangement.

On the other hand, the effort for a magnetic part to actuate the pneumatic part may be reduced if the nominal widths of the control and relay valves used were reduced - but this is at the expense of effective ventilation and regeneration of the air dryer. This also indirectly affects the risk of icing and - depending on the size of the magnetic part - also the risk of icing of the magnetic part of the vent valve arrangement.

This is where the invention comes in, the task of which is to specify a compressed air supply system with a vent valve arrangement that enables effective venting and regeneration with the lowest possible actuation effort in a rapidly ventilating pilot-controlled arrangement, with icing problems with a pilot and vent valve - so the vent valve assembly - if not eliminated, at least it can be bypassed.

The object relating to the compressed air supply system is achieved by a compressed air supply system according to claim 1; in particular with a "fast-venting, indirectly pilot-controlled vent valve arrangement".

The invention is based on a compressed air supply system with an indirectly pilot-controlled vent valve arrangement; in particular with a "rapidly venting, indirectly piloted vent valve arrangement" of the type mentioned at the beginning.

• - eine Druckluftzuführung, einen Druckluftanschluss zu einer Pneumatikanlage und einen Entlüftungsanschluss zur Umgebung,
• - eine Pneumatikhauptleitung zwischen der Druckluftzuführung und dem Druckluftanschluss, in welcher ein Lufttrockner angeschlossen ist, und
• - eine Entlüftungsleitung zu dem Entlüftungsanschluss, die zwischen der Druckluftzuführung und dem Lufttrockner an die Pneumatikhauptleitung angeschlossen ist, wobei in der Entlüftungsleitung ein über einen ersten und einen zweiten Entlüftungsventilanschluss angeschlossenes Entlüftungsventil angeschlossen ist,
• - einen Steuerdruckpfad mit einem im Steuerdruckpfad angeschlossenen Steuerventil als Teil einer Entlüftungsventilanordnung mit dem Steuerventil und dem Entlüftungsventil, wobei
• - das Entlüftungsventil als ein Relaisventil mit einem Steueranschluss gebildet ist, der über den Steuerdruckpfad mit dem Steuerventil pneumatisch verbunden ist zur Beaufschlagung des Steueranschlusses mit einem über den Steuerdruckpfad abzweigbaren Steuerdruck.

The compressed air supply system according to the invention for operating a pneumatic system has:

• - a compressed air supply, a compressed air connection to a pneumatic system and a ventilation connection to the environment,
• - A main pneumatic line between the compressed air supply and the compressed air connection, in which an air dryer is connected, and
• - A vent line to the vent connection, which is connected to the main pneumatic line between the compressed air supply and the air dryer, a vent valve connected via a first and a second vent valve connection being connected in the vent line,
• - A control pressure path with a control valve connected in the control pressure path as part of a vent valve arrangement with the control valve and the vent valve, wherein
• - The vent valve is formed as a relay valve with a control connection which is pneumatically connected to the control valve via the control pressure path in order to act on the control connection with a control pressure that can be branched off via the control pressure path.

According to the invention, it is provided that a control pressure can be supplied via the control pressure path on both sides of the vent valve, namely by means of the control valve to the control connection and without interruption to the control counter connection of the vent valve.

In particular, a control pressure can be supplied to both sides of a relay piston of the venting valve via the control pressure path, namely can be supplied without interruption to the control connection and a counterpart control connection of the venting valve. In particular - to put it another way - a control chamber on a first control side of the relay piston is pressurized via the control connection and a control chamber on an opposite control side of the relay piston is pressurized without interruption via a control mating connection.

With "uninterrupted" applied control pressure, a control pressure is meant which - as opposed to the control pressure applied to the control connection via the pneumatic control relay line in a switching state of the control valve - is applied to the control mating connection of the vent valve, in particular without adjusting means or at least independent of the switching position of a pneumatic one Thickening agent. A pneumatic actuating means can in particular be a pneumatic separating means and / or a valve, which in any case is not present in the control path directly to the counter-control connection. In particular, a control pressure is constantly applied to the control counter connection of the vent valve, inasmuch as the control pressure at the control connection can be switched by the control valve and, in contrast to this, the control pressure at the control counter connection from the compressed air supply, in particular the air compressor, or the compressed air connection, in particular the pneumatic system, is specified without interruption is.

In other words, the concept of the invention is that the control mating connection is pneumatically uninterrupted - in particular pneumatically permanently and / or free of a separating and / or adjusting means such as a valve or the like. pneumatic separating and / or adjusting means - is in connection with the main line and the control connection can still be switched by a normally open control valve.

According to the concept of the invention, the vent valve is closed in a currentless manner, i.e. pneumatically separates the vent line from the vent connection so that pressure cannot escape, which is ensured by the valve spring on the vent valve and which is even more the case in the pressurized state on both sides; the latter is guaranteed in particular due to the larger pressure-pressurable control surface of the relay piston at the control connection. Only a venting of the control connection through a switched control valve would open the vent valve or vent line and vent it into the environment.

The concept of the invention also leads to a compressed air supply system of claim 17 and a vehicle of claim 18 with a compressed air supply system according to the concept of the invention.

The compressed air supply system with the compressed air supply system according to the invention is characterized by a pneumatic system, in particular an air suspension system of a vehicle, preferably a passenger vehicle, in particular having a gallery, which has at least one branch line pneumatically connected to the gallery with a bellows and / or a reservoir as well as a bellows and / or the directional control valve upstream of the accumulator.

Accordingly, the invention is based on a method for operating a compressed air supply system according to the preamble of claim 19, in which the method steps of the characterizing part of claim 19 are provided according to the invention. According to the invention it is provided that in the method the control pressure is supplied via the control pressure path on both sides of the vent valve, namely by means of the control valve to the control connection and without interruption to the control counter connection of the vent valve.

• - Befüllen der Pneumatikanlage, wobei das Entlüftungsventil in einem ersten Schaltzustand zwischen dem ersten Entlüftungsventilanschluss und dem zweiten Entlüftungsventilanschluss zum Entlüftungsanschluss pneumatisch geschlossen ist, nämlich die Entlüftungsleitung für eine Druckluftströmung trennt, sodass eine Entlüftung unterbunden ist, insbesondere wobei in dem ersten Schaltzustand das Entlüftungsventil beidseitig druckbeaufschlagt ist, insbesondere unterhalb eines Restdrucks mit einer federkraftunterstützenden Ventilfeder,
• - Entlüften der Pneumatikanlage, wobei in einem zweiten Schaltzustand des Entlüftungsventils zwischen dem ersten Entlüftungsventilanschluss und dem zweiten Entlüftungsventilanschluss zum Entlüftungsanschluss pneumatisch geöffnet ist, nämlich die Entlüftungsleitung für eine Druckluftströmung öffnet, sodass eine Entlüftung möglich ist, insbesondere wobei in dem zweiten Schaltzustand

der Steueranschluss des Entlüftungsventils entlüftet ist.As part of a further development of the method for operating a compressed air supply system, it is provided that using the compressed air supply system according to the invention:

• - Filling the pneumatic system, the vent valve being pneumatically closed in a first switching state between the first vent valve connection and the second vent valve connection to the vent connection, namely separating the vent line for a compressed air flow, so that venting is prevented, in particular with the vent valve being pressurized on both sides in the first switching state is, in particular below a residual pressure with a spring force-supporting valve spring,
• - Venting of the pneumatic system, wherein in a second switching state of the vent valve between the first vent valve connection and the second vent valve connection to the vent connection is opened pneumatically, namely the vent line opens for a compressed air flow, so that venting is possible, in particular wherein in the second switching state

the control connection of the vent valve is vented.

With regard to the method, the function of the relay piston of the vent valve, which is acted upon by control pressure on both sides, results from the fact that, in the event of a lack of control pressure at the control connection, the vent valve is opened pneumatically against the spring force of the valve spring as a result of the control counterpressure in the vent line, i.e. a flow of compressed air to vent the compressed air supply system A vent line to the vent connection is made possible. One advantage of the invention is therefore that the control valve only needs to be switched for venting, although it is open in the depressurized state between the main line and the control connection of the venting valve.

Based on the considerations mentioned at the outset, the invention has recognized that a control pressure in a control pressure path can be comparatively low if the control connection has a valve spring in a relay piston of the vent valve that is pressurized on both sides. The invention has recognized that in this case the relay piston of the vent valve can be designed in such a way that the opening and closing forces are sufficient, even with a comparatively low control pressure, to ensure reliable functioning of the vent valve - pneumatic part of the vent valve arrangement; a magnet of the actuating control valve - magnet part of the vent valve arrangement - can thus be selected to be comparatively small with a low control pressure, which reduces the risk of freezing and costs.

Nevertheless, the nominal opening width of the relay valve can be selected to be sufficiently large to ensure efficient venting and regeneration of the air dryer.

Advantageous further developments of the invention can be found in the subclaims and indicate in detail advantageous possibilities for realizing the concept explained above within the scope of the task and with regard to further advantages.

The control connection advantageously has a valve spring. A spring force-supporting valve spring is advantageously assigned to the control connection of the vent valve such that a spring force of the valve spring acts in the direction of a pneumatic force at the control connection and / or counter to a direction of a pneumatic force at the counter-control connection. The size of the valve spring is advantageously provided to set the residual pressure. In particular, the valve spring is designed to support the control connection to which the control pressure is applied. It is therefore preferably provided that a control chamber acted upon by control pressure on a control pressure side of the relay piston is supported by spring force against a control counterpressure acted upon on an opposite control side of the relay piston.

It is also advantageously provided that a pressure limiting element connected to the control pressure path and / or to the vent line is formed, in particular for venting a residual pressure and / or excess pressure of the control pressure path and the vent line to a vent line to the vent connection.

The further development has recognized that as a result of the pneumatic actuation of the relay valve and, nevertheless, with a small nominal diameter of the control valve, there is a risk of icing, which can in any case be bypassed with a pressure limiting element connected to the control pressure path and / or to the vent line.

Advantageously, the control pressure can be applied to a relay piston of the vent valve via the control connection and the control counter connection, the control pressure being able to be supplied via the control pressure path on both sides of the relay piston of the vent valve. The pressure cylinder of the vent valve is preferably designed as a differential cylinder. When the cylinder of the relay valve is designed as a differential cylinder, opening and closing forces and opening and closing speeds of the vent valve can advantageously be selected. In particular, the control surface to the control chamber for the control connection of the vent valve is larger, preferably very much larger, than the control counter surface to the control counter chamber to the control counter connection of the vent valve. A ratio of the control surface to the control counter surface is preferably in the ratio of diameters of 0.35 mm to 0.15 mm. Ratio values between 2 and 2.5, advantageously between 1.5 and 3, are advantageous in order to achieve a residual pressure below 0.75 bar, preferably below 0.5 bar, particularly preferably below 0.1 bar. In particular, when the control valve is switched and the control connection of the venting valve is vented, venting in the main line is always preferably below 0.1 bar - i.e. down to practically almost 0 bar - depending on the spring force of the valve spring on the side of the control connection of the venting valve. Any remaining residual pressure in the system is basically only determined by the balance of forces between the pressure surface of the control counter connection and the force of the spring on the side of the control connection. As a result, the force on the smaller control surface in the control counter space at the control counter connection of the vent valve is relatively small compared to the force on the control surface in the control space at the control connection of the vent valve.

With a correspondingly low spring force of the valve spring in the order of magnitude of the force on the counter-control surface, the vent line can pass through the vent valve down to a comparatively low residual pressure, i.e. a residual pressure close to 0 bar, for example at 0.5 bar or even less, for example 0.25 bar, 0.2 bar or even below 0.1 bar. Above a comparatively low residual pressure of close to 0 bar, for example up to above or equal to 0.1 bar, the compressed air supply system can be vented via the vent line before the valve spring brings the vent valve back into a switching position in the absence of control back pressure as a result of the venting, which pneumatically controls the vent line interrupts, that is, disconnects; so the vent valve closes.

During a filling process, i.e. pressure build-up in the system, the vent valve is securely closed due to the control pressure area selected to be relatively large compared to the control pressure counter area. During regeneration, it is open up to the comparatively low residual pressure. As a result of the control pressure which is comparatively low for the function of the vent valve, namely a control pressure which is comparatively low in order to nevertheless allow a relatively large force on the control pressure surface of the relay piston due to its size, the solenoid of the control valve, d. H. of the magnetic part of the vent valve arrangement, that is to say the nominal width of the same, be selected to be comparatively small. The effort for actuating the pneumatic part of the vent valve arrangement - in particular the relay valve - with a magnet part of the vent valve arrangement - in particular the control valve - with a comparatively small nominal diameter and a correspondingly small magnet is therefore low according to the concept of the invention, which is a particular advantage.

• - eine Hauptzweig-Steuerleitung an einem Steuerdrucknehmeranschluss des Steuerventils zur Zuführung des Steuerdrucks zum Steuerdrucknehmeranschluss, und/oder
• - eine pneumatische Steuerrelaisleitung an dem Steueranschluss des Entlüftungsventils zur Zuführung des Steuerdrucks zum Steueranschluss vom Steuerdruckgeberanschluss des Steuerventils, insbesondere zur Zuführung des Steuerdrucks zum Steueranschluss bei unbestromtem Steuerventil, und/oder
• - eine Zweig-Steuerleitung an dem Steuergegenanschluss des Entlüftungsventils zur Zuführung des Steuerdrucks (p) zum Steuergegenanschluss, insbesondere unterbrechungsfreien Zuführung des Steuerdrucks zum Steuergegenanschluss.

The control pressure path advantageously has:

• - A main branch control line on a control pressure receiver connection of the control valve for supplying the control pressure to the control pressure receiver connection, and / or
• - A pneumatic control relay line to the control connection of the vent valve for supplying the control pressure to the control connection from the control pressure transmitter connection of the control valve, in particular for supplying the control pressure to the control connection when the control valve is de-energized, and / or
• - a branch control line at the control counter connection of the vent valve for supplying the control pressure ( p ) to the mating control connection, in particular uninterrupted supply of the control pressure to the mating control connection.

• - einen Steuergegenraum des Entlüftungsventils pneumatisch zu verbinden mit einem Steuerraum des Entlüftungsventils zur Führung des Steuerdrucks, wobei eine Entlüftung eines Restdrucks an den Steuerdruckpfad und/oder an die Entlüftungsleitung anschließt.

In other words, the control pressure path can also be interpreted in the form of a feedback line, of this type

• - To pneumatically connect a control chamber of the vent valve to a control chamber of the vent valve for guiding the control pressure, with venting of a residual pressure connecting to the control pressure path and / or to the vent line.

In the context of a first preferred further variant, it is provided that the control pressure path is connected to the main pneumatic line, in particular is connected to the main pneumatic line between the air dryer and the compressed air connection. To this end, the control path can advantageously have: a main control line between a main branch connection on the main pneumatic line and a main branch control line to the control pressure receiver connection of the control valve, in particular with a branch control line connecting to the main control line.

In the context of a second preferred further variant, it is provided that the control pressure path is connected to a pressure line at the compressed air connection, in particular to a gallery or to a pressure accumulator line. To this end, the control path can advantageously have: a pressure line between a main branch connection in the filling direction downstream of the compressed air connection and a main branch control line to the control pressure sensor connection of the control valve, which is connected to the pressure line, a branch control line being connected to the main branch control line.

As part of a further development, a pressure limiting element connected to the control pressure path is designed to effect a venting of the control pressure path, in particular a residual pressure and / or overpressure of the control pressure path, in particular a venting to a venting line to the venting connection. In particular, with regard to the pressure-limiting element connected to the control pressure path and / or to the vent line, it is provided that the pressure-limiting function of the pressure-limiting element takes effect in the event of a pressure rising above a maximum overpressure - e.g. when the pneumatic system is being filled or when the switching valve to the pneumatic system is not opening.

A pressure limiting element can be formed in particular in the form of an external pressure limiting valve on the vent line or an internal pressure limiting valve on the control pressure path or it can be integrated into a control valve as a pressure limiting device. In the case of an external pressure relief valve, this is advantageous on the Vent line connected. In the case of an internal pressure limiting valve or a pressure limiting element integrated in the control valve, this is preferably connected to the control pressure path.

It is advantageously provided that the pressure limiting element
In a first variant, it is designed as an internal pressure relief valve on the control pressure path, and the bleed valve is bridged on the control pressure side, a bleed outlet of the pressure relief element being pneumatically connected to the bleed discharge line to the bleed connection and a pressure inlet of the pressure limiting element being pneumatically connected to the pneumatic control relay line.

It is advantageously provided that the pressure limiting element
in a second variant, alone or in combination with the first variant, is designed as a pressure limiter which is integrated in the control valve, the pressure limiter being pneumatically connected to the control valve and the control pressure path.

• - als eine Druckbegrenzung ausgebildet ist, die im Steuerventil integriert ist; und/oder
• - als ein externes Druckbegrenzungsventil in einer pneumatischen Verbindung ausgebildet ist, die das Entlüftungsventil entlüftungsdruckseitig überbrückt, und/oder
• - als ein internes Druckbegrenzungsventil in einer pneumatischen Verbindung ausgebildet ist, die das Entlüftungsventil steuerdruckseitig überbrückt.

In the context of these particularly preferred variants, it is advantageously provided that the pressure limiting element

• - Is designed as a pressure limiter which is integrated in the control valve; and or
• - Is designed as an external pressure relief valve in a pneumatic connection that bridges the vent valve on the vent pressure side, and / or
• - Is designed as an internal pressure relief valve in a pneumatic connection that bridges the vent valve on the control pressure side.

• - bei einer Steuerdruckentlüftung am Steueranschluss, insbesondere bei bestromtem Steuerventil, und gegen eine Federkraft der Ventilfeder (124.3) am federkraftunterstützten Steueranschluss, die Entlüftungsleitung (6) pneumatisch zur Entlüftung zu öffnen und/oder
• - unterhalb eines Restdrucks, insbesondere unterhalb von 0.5 bar Restdruck, mit der Federkraft der Ventilfeder am federkraftunterstützten Steueranschluss zur pneumatischen Unterbrechung der Entlüftungsleitung zu schließen, und/oder
• - oberhalb eines Restdrucks, insbesondere oberhalb von 0.5 bar Restdruck, ohne eine Steuerdruckentlüftung am Steueranschluss und bei beidseitig des Entlüftungsventils zugeführtem Steuerdruck zur pneumatischen Unterbrechung der Entlüftungsleitung zu schließen.

As part of a further development, it is advantageously provided that the vent valve is designed,

• - In the case of control pressure venting at the control connection, especially when the control valve is energized, and against a spring force of the valve spring (124.3) at the spring-assisted control connection, the vent line ( 6th ) to open pneumatically for venting and / or
• - to close below a residual pressure, in particular below 0.5 bar residual pressure, with the spring force of the valve spring on the spring-force-assisted control connection for the pneumatic interruption of the vent line, and / or
• - Above a residual pressure, in particular above 0.5 bar residual pressure, without closing a control pressure vent at the control connection and with control pressure supplied to both sides of the vent valve for pneumatic interruption of the vent line.

• - das Entlüftungsventil in einem ersten Schaltzustand zwischen dem ersten Entlüftungsventilanschluss und dem zweiten Entlüftungsventilanschluss zum Entlüftungsanschluss pneumatisch geschlossen ist, nämlich die Entlüftungsleitung für eine Druckluftströmung trennt, sodass eine Entlüftung unterbunden ist, insbesondere wobei in dem ersten Schaltzustand das Entlüftungsventil beidseitig druckbeaufschlagt ist, insbesondere unterhalb eines Restdrucks mit einer federkraftunterstützenden Ventilfeder, und
• - in einem zweiten Schaltzustand des Entlüftungsventils zwischen dem ersten Entlüftungsventilanschluss und dem zweiten Entlüftungsventilanschluss zum Entlüftungsanschluss pneumatisch geöffnet ist, nämlich die Entlüftungsleitung für eine Druckluftströmung öffnet, sodass eine Entlüftung möglich ist, insbesondere wobei in dem zweiten Schaltzustand der Steueranschluss des Entlüftungsventils entlüftet ist.

In particular, with regard to the specific connection of the vent valve, it can advantageously be provided that

• - The vent valve is pneumatically closed in a first switching state between the first vent valve connection and the second vent valve connection to the vent connection, namely separates the vent line for a compressed air flow so that venting is prevented, in particular wherein in the first switching state the vent valve is pressurized on both sides, in particular below one Residual pressure with a spring force-assisting valve spring, and
• - In a second switching state of the vent valve between the first vent valve connection and the second vent valve connection to the vent connection is pneumatically opened, namely the vent line opens for a compressed air flow so that venting is possible, in particular with the control connection of the vent valve being vented in the second switching state.

• - das Steuerventil in einem ersten, unbestromten Schaltzustand zwischen einem Steuerdrucknehmeranschluss und einem Steuerdruckgeberanschluss zum Steueranschluss pneumatisch geöffnet ist, nämlich eine Druckluftströmung zulässt, sodass eine Druckluftströmung möglich ist, um den Steueranschluss des Entlüftungsventils mit Druck zu beaufschlagen und das Entlüftungsventil von dem zweiten Schaltzustand in den ersten Schaltzustand zu überführen; und
• - in einem zweiten, bestromten Schaltzustand zwischen dem Steuerdrucknehmeranschluss und dem Steuerdruckgeberanschluss zum Steueranschluss pneumatisch geschlossen ist, nämlich für eine Druckluftströmung trennt, sodass eine Druckluftströmung unterbunden ist, um den Steueranschluss des Entlüftungsventils zu entlüften und das Entlüftungsventil von dem ersten Schaltzustand des Entlüftungsventils in den zweiten Schaltzustand des Entlüftungsventils zu überführen.

As part of a further development, it is advantageously provided with regard to the specific connection of the control valve that

• - the control valve is pneumatically opened in a first, de-energized switching state between a control pressure sensor connection and a control pressure transmitter connection to the control connection, namely allows a compressed air flow so that a compressed air flow is possible to pressurize the control connection of the vent valve and the vent valve from the second switching state to to transfer first switching state; and
• - is pneumatically closed in a second, energized switching state between the control pressure sensor connection and the control pressure transducer connection to the control connection, namely separates for a compressed air flow, so that a compressed air flow is prevented in order to vent the control connection of the vent valve and the vent valve from the first switching state of the vent valve to the second To transfer the switching state of the vent valve.

• - das Entlüftungsventil eine dem Steueranschluss zugeordnete Steuerfläche mit größerer Fläche aufweist als eine dem Steuergegenanschluss zugeordnete Gegensteuerfläche mit kleinerer Fläche und/oder
• - das Entlüftungsventil eine über den ersten und den zweiten Entlüftungsventilanschluss in der Entlüftungsleitung angeordneten Entlüftungsquerschnitt aufweist, dessen Fläche kleiner ist als die dem Steueranschluss zugeordnete Steuerfläche und kleiner ist als die dem Steuergegenanschluss zugeordnete Gegensteuerfläche.

In the context of a further development, it is advantageously provided for realizing a comparatively low residual pressure, in particular close to 0 bar, and in this respect an advantageous mode of operation of the vent valve that

• - The vent valve has a control surface assigned to the control connection with a larger area than a counter control area assigned to the counterpart control connection with a smaller area and / or
• - The vent valve has a vent cross-section arranged in the vent line via the first and the second vent valve connection, the area of which is smaller than the control surface assigned to the control connection and smaller than the counter control surface assigned to the mating control connection.

In particular, it is provided that the vent valve has a relay piston that can be pressurized with control pressure for switching the vent valve into an open or closed switching state, the control pressure at the control connection being switchable by the control valve and the control pressure at the counter control connection from the compressed air supply, in particular the air compressor, or the compressed air connection, in particular the pneumatic system is specified. A residual pressure thus results in particular from the equilibrium of forces between pressure times the area of the control pressure mating connection versus the force of the valve spring on the side of the control connection.

As part of a particularly preferred development, it is advantageously provided that the control valve is a 3/2-way valve and the vent valve is a 2/2-way valve, preferably connected to the vent line for venting, in particular the 3/2-way valve, preferably in the second switching state, via a control vent line, and the vent valve via the vent line.

Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily intended to represent the embodiments to scale; rather, the drawing, where useful for explanation, is shown in a schematic and / or slightly distorted form. With regard to additions to the teachings that can be seen directly from the drawing, reference is made to the relevant prior art. It must be taken into account here that various modifications and changes relating to the form and the detail of an embodiment can be made without deviating from the general idea of the invention. The features of the invention disclosed in the description, in the drawing and in the claims can be essential for the development of the invention both individually and in any combination. In addition, all combinations of at least two of the features disclosed in the description, the drawing and / or the claims fall within the scope of the invention. The general idea of the invention is not restricted to the exact form or the detail of the preferred embodiments shown and described below or restricted to an object that would be restricted in comparison to the object claimed in the claims. In the case of the specified measurement ranges, values lying within the stated limits should also be disclosed as limit values and be able to be used and claimed as required. For the sake of simplicity, the same reference symbols are used below for identical or similar parts or parts with an identical or similar function.

• 1A ein pneumatisches System 100A gemäß dem Stand der Technik mit einer direkt entlüftenden Druckluftversorgungsanlage 10A,
• 1B ein weiteres pneumatisches System 100B gemäß dem Stand der Technik mit einer schnell entlüftenden Druckluftversorgungsanlage 10B,
• 1C ein weiteres pneumatisches System 100C gemäß dem Stand der Technik mit einer normal entlüftenden Druckluftversorgungsanlage 10C,
• 2 eine besonders bevorzugte erste Ausführungsform einer Druckluftversorgungsanlage mit einer schnell entlüftenden Druckluftversorgungsanlage wie in 1B, die eine indirekt vorgesteuerte Lüftungsventilanordnung mit einem über einen Steuerdruckpfad an der Pneumatikhauptleitung beidseitig steuerdruckbeaufschlagten Relaiskolben gemäß dem Konzept der Erfindung aufweist, und ein Druckbegrenzungselement, das an den Steuerdruckpfad anschließt, im Steuerventil der Lüftungsventilanordnung integriert ist,
• 3 eine zweite bevorzugte Ausführungsform einer Druckluftversorgungsanlage, ebenfalls mit einer schnell entlüftenden Druckluftversorgungsanlage wie in 1B, die --wie die erste Ausführungsform der 2-- eine indirekt vorgesteuerte Lüftungsventilanordnung mit einem über einen Steuerdruckpfad an einer Druckleitung beidseitig steuerdruckbeaufschlagten Relaiskolben gemäß dem Konzept der Erfindung aufweist,
• 4A eine dritte Ausführungsform einer Druckluftversorgungsanlage ebenfalls mit einer schnell entlüftenden Druckluftversorgungsanlage wie in 1B, die --wie die erste Ausführungsform der 2-- eine indirekt vorgesteuerte Lüftungsventilanordnung mit einem über einen Steuerdruckpfad an der Pneumatikhauptleitung beidseitig steuerdruckbeaufschlagten Relaiskolben gemäß dem Konzept der Erfindung aufweist, und ein Druckbegrenzungselement das an eine pneumatische Steuerrelaisleitung an dem Steueranschluss des Entlüftungsventils anschließt,
• 4B eine konstruktive Realisierung der dritten Ausführungsform;
• 5 ein Ablaufschema zur Erläuterung eines grundsätzlichen Verfahrensablaufs bei Entlüftung einer Druckluftversorgungsanlage gemäß der bevorzugten Ausführungsformen, nämlich bei einem Entlüftungsvorgang bis unterhalb eines bevorzugt niedrigen Restdrucks nahe 0 bar, bzw. bei einem Befüllvorgang unter Vermeidung eines Überdrucks;
• 6 ein Fahrzeug mit einer Druckluftversorgungsanlage gemäß einer der Ausführungsformen

Further advantages, features and details of the invention emerge from the following description of the preferred embodiments and on the basis of the drawings, which show in:

• 1A a pneumatic system 100A according to the state of the art with a directly venting compressed air supply system 10A ,
• 1B another pneumatic system 100B according to the state of the art with a rapidly venting compressed air supply system 10B ,
• 1C another pneumatic system 100C according to the state of the art with a normally venting compressed air supply system 10C ,
• 2 a particularly preferred first embodiment of a compressed air supply system with a rapidly venting compressed air supply system as in FIG 1B which has an indirectly pilot-controlled ventilation valve arrangement with a relay piston according to the concept of the invention to which control pressure is applied on both sides via a control pressure path on the main pneumatic line, and a pressure limiting element which is connected to the control pressure path is integrated in the control valve of the ventilation valve arrangement,
• 3 a second preferred embodiment of a compressed air supply system, also with a rapidly venting compressed air supply system as in FIG 1B , which - like the first embodiment of the 2 - Has an indirectly pilot-controlled ventilation valve arrangement with a relay piston according to the concept of the invention, which is acted upon by control pressure on both sides via a control pressure path on a pressure line,
• 4A a third embodiment of a compressed air supply system also with a rapidly venting compressed air supply system as in FIG 1B , which - like the first embodiment of the 2 - has an indirectly pilot-controlled ventilation valve arrangement with a relay piston according to the concept of the invention, which is acted upon by control pressure on both sides via a control pressure path on the main pneumatic line, and a pressure limiting element which connects to a pneumatic control relay line at the control connection of the venting valve,
• 4B a structural implementation of the third embodiment;
• 5 a flowchart for explaining a basic process sequence for venting a compressed air supply system according to the preferred embodiments, namely for a venting process to below a preferably low residual pressure close to 0 bar, or for a filling process while avoiding overpressure;
• 6th a vehicle with a compressed air supply system according to one of the embodiments

1A shows a - per se known - pneumatic system 100A with a compressed air supply system 10A and a pneumatic system 90 present in the form of an air suspension system 90.1 of a vehicle 1000 . Where appropriate, the same reference symbols are used for identical or similar parts or parts with identical or similar functions. The air suspension system has four so-called bellows 91 on, each with an air spring 92 for a wheel of a vehicle not shown in detail 1000 assigned.

The bellows 91 are - present in a valve block 20th with four valves - each via a normally closed solenoid valve 93 to a common gallery 95 forming pneumatic line connected, with a supply line 5 ' via a gallery connection 2 ' the pneumatic connection between the compressed air supply system 10A and the pneumatic system 90 forms. The valve block 20th can have different or fewer solenoid valves and / or solenoid valves arranged in a double valve block. A gallery is generally to be understood as any type of collecting line from which branch lines to bellows 91 or a line to the compressed air supply system 10A go off. The compressed air supply system 10A serves to operate the pneumatic system 90 in the form of the air suspension system 90.1 and takes care of the gallery 95 the same via a compressed air connection 2 . The compressed air supply system 10A also has a vent port 3 on a vent line 3 ' and an air supply 0 with a suction. Downstream of the compressed air connection in the filling direction 2 is the air suspension system 90.1 with the controllable solenoid valves 93 arranged. The exhaust port 3 downstream in the venting direction is a filter 68 downstream. The air supply 0 is upstream is a filter 66 upstream.

In a pneumatic connection between the air supply 0 and compressed air supply 1 instructs the compressed air supply system 10A in addition, an air compressor 21 in the form of a compressor, which is driven by a motor M to supply the compressed air supply 1 with compressed air is provided. In a pneumatic connection between the compressed air supply 1 and compressed air connection 2 is also an air dryer 60 and a regeneration throttle 63 arranged. The filter 66 , the air supply 0 , the air compressor 21 , the compressed air supply 1 , the air dryer 60 and the regeneration throttle 63 are together with the compressed air connection 2 in one to the gallery 95 leading compressed air supply line 5 arranged in this order. Here, the section forms between the compressed air supply 1 and the compressed air connection 2 or the gallery connection 2 ' a main pneumatic line 5 , being the section of the main pneumatic line 5 between the compressed air connection 2 and the gallery connection 2 ' as a supply line 5 ' is designated.

In a pneumatic connection between the compressed air supply 1 and vent connection 3 the compressed air supply system 10A in the form of a vent line 6th is a vent valve assembly 120A in the form of a controllable normally closed solenoid valve 122A for releasing air through the exhaust vent 3 ' to the vent connection 3 intended. The solenoid valve 122A is in a ventilation line that forms a pneumatic connection 6th with a venting throttle 64 and the vent connection 3 on the vent line 3 ' arranged. In other words, in the case of the normally closed solenoid valve 122A when the magnetic part is not activated, the pneumatic part is closed. In the present case, the solenoid valve is concrete 122A designed for direct switching of a compressed air volume. The pneumatic part in the vent line that can be actuated directly via the magnetic part 6th the compressed air supply line 5 is normally closed like this in 1A is shown.

A line section of the vent line on the compressed air supply side, forming a pneumatic chamber 6th is on the compressed air supply 1 for the pneumatic connection of the solenoid valve 122A to the compressed air supply line 5 connected. This has the consequence that in the event of a venting of the compressed air supply system 10A via the vent line 6th Compressed air via the vent line 3 ' is vented, which is before the air dryer 60 is removed.

the end 1A it can be seen that the compressed air supply system 10A with a vent valve assembly 120A in the form of a directly controlled solenoid valve 122A is designed without a control valve and via a control connection 86 direct switching of the entire compressed air volume is possible. The vent valve arrangement is shown here 120A a single solenoid valve 122A as a vent valve. A control valve is not provided. A pressure limiter 123 can be provided on the solenoid valve 122A , in which the pressure is tapped in the vent line 6th the pressure for the solenoid valve 122A can be restricted. In this way, a certain variability or tolerance with regard to a pressure limitation can be achieved even at a comparatively high operating pressure.

The functionality of the compressed air supply system results in detail 10A , based on 1A clarifies as follows. The compressed air supply 1 is made by sucking air through the filter 66 and the air supply 0 supplied with compressed air by the air compressor driven by the motor M 21 sucked in air is compressed. The pneumatic system 90 in the form of the air suspension system 90.1 becomes from the compressed air supply 1 via the air dryer 60 and the regeneration throttle 63 supplied with compressed air. So remains for a filling process BV first the vent line 30 without energizing the solenoid valve 122A closed with a control current to build up pressure in the bellows 91 the pneumatic system 90 to enable; this as in 1A shown. The compressed air supply line is for this purpose 5 the compressed air supply system 10A via the compressed air connection 2 with the gallery 95 the pneumatic system 90 tied together. When a cut-off pressure is reached PA in the pneumatic system 90 , here in a pressure range of 5 to 10 bar in the bellows, the compressed air supply system 10A vented. For the venting throttle 64 a larger nominal width is provided than for the regeneration throttle 63 so that one for the regeneration of the air dryer 60 the greatest possible pressure change amplitude can arise. This allows an advantageous venting of the compressed air supply system 10A and / or regeneration of the air dryer 60 . In the present case, the compressed air supply system can be vented 10A after the cut-off pressure has been reached PA , by switching off the via the control connection 86 applied control current for the then energized to open solenoid valve 122A take place. Venting in the event of a vehicle lowering during normal operation can be done through the solenoid valve that is opened in this way 122A take place. This is achieved through a suitable pressure drop across the air dryer 60 a regeneration of the air dryer 60 as well as flexible and fast venting by designing the nominal width of the throttles 63 , 64 appropriately guaranteed.

Usually a bellows pressure can act on the solenoid valves 93 do not press open and supports a valve spring in that in the present case a bellows pressure is applied over a valve armature. With pressure fluctuations in the bellows 91 , as can occur on rough roads or other dynamic influences, is avoided in this way that the solenoid valves 93 be pushed on. Practically only in the case of an unintentionally sustained delivery of the air compressor can a gallery pressure become so high that a bellows valve is pushed open and the vehicle is unintentionally lifted. This could lead to unstable driving conditions. A pressure limiter reliably avoids such a case in systems with closed ventilation circuits. In the case of a currentless open circuit described here, however, such a risk is avoided per se, since an air compressor would mostly convey into the open air.

In DE 10 2014 009 419 is according to [0064] and [0068] to that there 1B (i.e. in the DE 10 2014 009 419 ) explains how a purely pneumatic control of the vent valve according to a concept of a compressor-controlled vent functionality can be implemented with a "direct venting arrangement" as a vent valve arrangement 120A . The vent valve can be acted upon pneumatically on both sides and is part of a vent valve arrangement 120A in the form of a controllable normally closed solenoid valve 122A for releasing air through the exhaust vent 3 ' to the vent connection 3 which, in addition to the vent valve, also has a check valve arranged in a control line. I. E. there, the operation of the compressor is sufficient to build up a pressure in the compressor chamber that is sufficient for a control pressure applied to the pressure control connection of the vent valve. The control pressure is sufficiently high to move the actuatable pneumatic part of the vent valve into a switching position in which the pressure-side valve connection and the vent-side valve connection are pneumatically separated; ie the vent line 6th closed is. This will remove the vent line 6th pneumatically interrupted by the vent valve, ie the dryer outlet of the air dryer 60 or the compressed air supply is against the ventilation connection 3 pneumatically separated. Thus, via the compressed air supply 1 sufficient compressed air - in the air dryer 60 dried-and over the first throttle 63 at the compressed air connection 2 for filling the pneumatic system 90 to provide.

1B and 1C in the present application show two more Compressed air supply systems according to the prior art, each with a different vent valve arrangement 120B , 120C , where in the vent line 6th a relay valve 124B , 124C is arranged to hold a residual pressure. Here is the relay valve 124B , 124C designed to maintain a residual pressure in the range up to 1 bar, in particular a residual pressure up to 3 bar.

1B in the present application shows a - per se known - pneumatic system 100B with a compressed air supply system 10B and a pneumatic system 90 , present in the form of an air suspension system 90.1 . Identical or similar parts or parts with identical or similar functions have the same reference symbols as in 1A been used. The following will mainly focus on the differences between the 1A and 1B Referenced.

In contrast to the pneumatic system 100A in the present application it is the pneumatic system 100B with a compressed air supply system 10B equipped, in which the vent valve assembly 120B - again closed without current - but in the present case is designed as a "rapidly ventilating, indirectly pilot-controlled arrangement, here as a solenoid valve arrangement. Specifically, this means that the normally closed solenoid valve arrangement 120B for the indirect switching of a volume of compressed air, a control valve exposed to partial pressure 126B to control a relay valve 124B having. The control valve 126B is in the form of a solenoid valve with a magnetic part and a pneumatic part, the relay valve 124B via a control connection 124.1 with the pneumatic part of the control valve 126B is pneumatically connected. In the normally closed state of the control valve 126B is where the solenoid part of the control valve is located 126B in a non-activated state and the pneumatic part of the control valve 126B is closed, like the one in 1B is shown; the control valve 126B is via the control vent line 3 " for venting 3 ' and vent connection 3 vented. The control pressure is at the control connection 124.1 of the relay valve 124B in the control line 7 only when the control valve 126B is energized.

This is advantageous in this fast-venting arrangement for the compressed air supply system 10B is that due to the comparatively small nominal size of the regeneration throttle 63 in the compressed air supply line 5 compared to the larger nominal diameter of the venting throttle 64 in the vent line 6th only a relatively small one from the total pressure of a compressed air volume in the compressed air supply line 5 resulting force to control the relay valve 124B via the control valve 126B is required.

Nevertheless, the main compressed air volume is via the vent line 6th and the venting throttle 64 as well as the relay valve 124B via the vent line 3 ' to the vent connection 3 vented. An advantage of this quickly venting solenoid valve arrangement 120B at the compressed air supply system 10B is that the entire volume of compressed air does not have to be passed through a single solenoid valve, but rather a small resultant force from the control valve via the control line 7 126B supplied partial compressed air volume is sufficient. This design, similar in principle to a positively controlled or servo-controlled valve arrangement, enables the operating pressure to be increased to a comparatively high pressure level and, at the same time, the switching of high volumes of compressed air via the relay valve 124B made possible.

The relay valve 124B can be designed with a comparatively large nominal diameter. In addition, the ratio of the smaller nominal diameter of the regeneration throttle 63 to the larger nominal diameter of the venting throttle 64 chosen so that an effective regeneration of the air dryer 60 when venting the compressed air supply system 10B is possible. The greater the ratio of the nominal widths, the greater the pressure change amplitude, in particular the pressure reduction, on the air dryer 60 are advantageously available for regeneration.

Specifically shows 1C in the present application - for a pneumatic system not shown in detail 100C with the well-known pneumatic system 90 - a compressed air supply system 10C , in which, in turn, the same reference numerals are used for identical or similar parts or parts with an identical or similar function. The following are mainly the differences to the aforementioned compressed air supply system 10A the 1A respectively. 10B the 1B explained.

The present - well-known - compressed air supply system 10C sees a vent valve assembly 120C in the form of a so-called "normally ventilating, pilot-controlled arrangement", which is switched to be de-energized and closed. The vent valve arrangement can be seen 120C from a normally closed solenoid valve as a control valve 126C with a magnetic part and a pneumatic part. The vent valve arrangement also has 120C a relay valve 124C which is arranged with its pneumatic part in the control line 7. It is the total pressure of the air pressure volume in the compressed air supply line 5 on the control valve 126C that this is in the activated state of the control valve 126C as pilot pressure to the relay valve 124C passes on. This arrangement can be used with comparatively small nominal widths for the control valve 126C and yet comparatively large nominal widths of the ventilation throttle 64 in the Compared to the regeneration throttle 63 at the relay valve 124C be realized to a volume of compressed air from the compressed air supply line 5 to the vent connection 3 via the vent line 6th to vent. In addition, there is a sufficiently high pressure change amplitude to regenerate the air dryer 60 ensured. Due to the throttle connected in parallel 63.3 in the branch line 8 of the vent valve arrangement designed as a further vent line 120C is the total pressure of the de-energized closed control valve 126C in the control line 7 designed as a vent line and only when energized also at the relay valve 124C at.

The compressed air supply line 5 and the branch line 8 is connected to a first one in the main pneumatic line 5 arranged, check valve 48 secured. As a result, the entire air flow is through a side path 5 ″ of the main pneumatic line when venting 5 , having the control line 7, the control valve 126C and a second check valve 49 , and during this side path 5 "through one or more regeneration throttles 63.1 , 63.2 , 63.3 -With the present three possible locations for the arrangement for a first, second and / or third regeneration throttle 63.1 , 63.2 , 63.3 are shown - as well as by the air dryer 60 and the venting throttle 64 and the relay valve which is then opened in a controlled manner 124C into the vent line 6th steered.

In case of opening the gallery 95 switches the relay valve 124C as a result of a control connection 124.1 applied control pressure when energizing the control valve 126C and the control pressure is generated via the control valve, which is arranged in the control line 7, is closed when de-energized and is opened by the energization 126C to the control connection 124.1 conveyed. So the relay valve opens 124C the vent line 6th for ventilation 3 . On the other hand, the second check valve prevents 49 controlling the relay valve 124C via the branch line 8 when conveying an air stream from the compressed air supply 1 to the compressed air connection 2 when the control valve 126C is also closed, ie not energized. The control valve 126C is vented in the de-energized state via a control vent line 3 " for venting 3 ' and for ventilation 3 .

The first check valve also blocks 48 the gallery 95 to the air dryer 60 to change the pressures in the pneumatic system 90 unwanted filling of the air dryer 60 to avoid. Here is the control valve 126C also closed, ie energized.

In WO 2016/026577 A1 to 8th ff is explained on page 30/31 how with such a "norma / venting pilot-operated arrangement" the 1C An additional ventilation line as a feedback line is connected to a ventilation return space of a ventilation valve - namely the relay valve 124C - which thus pneumatically connects the second control connection to the ventilation connection of the ventilation valve via the ventilation return space. As a result, the second control connection can be designed to receive a second control part pressure on the relay piston extension which acts in addition to a first control part pressure of the first control connection. The second control connection on the relay piston extension is thus designed as a counter control connection for receiving the second control part pressure, which acts in addition to the first control part pressure of the first control connection when the control valve is switched through and opened in the energized state. This control part pressure is in particular limited in time, to the activation time of the control valve in the energized state, and acts on the relay piston extension in the opposite direction to the first control part pressure of the first control connection on the relay piston. In other words, the control pressure - but in any case a control pressure derived from it - is applied to the first and second control surface of the relay piston extension and thus also has an effect on the relay piston. For this purpose, a throttle in the further vent line to the vent back space can be designed with a comparatively small nominal width; Among other things, this can dampen the movement of a relay piston - namely relay valve 124C.

Conceptually there is between the compressed air supply system 10C the 1C and the compressed air supply system 10B the 1 B. each with an indirectly piloted venting solenoid valve arrangement the common feature that a relay valve 124B a vent valve assembly 120B or a relay valve 124C of a vent valve arrangement 120C is arranged in a "dry" line - so in the venting direction "behind" the air dryer 60 is arranged - namely in each case in the vent line 6th is arranged. This means that there is generally a comparatively low risk of a relay valve 124B or a relay valve 124C is damaged due to external influences, for example freezing or the like. Furthermore, both require indirectly pilot operated vent valve assemblies 120B , 120C a minimum pilot pressure to use with the relay piston of the relay valve 124B , 124C a necessary minimum cross-section, namely at least the cross-section of the ventilation throttle 64 to be able to share. A minimum pilot pressure is required for the relay piston to open properly. This can in the case of the rapidly venting vent valve arrangement 120B at least on the regeneration throttle 63 in the case of regeneration when lowering the vehicle 1000 be built up dynamically.

In both cases of the indirectly piloted solenoid valve arrangements 120B , 120C can be a spring-loaded relay valve 124B or spring-loaded relay valve 124C on the one hand, assume a residual pressure holding function if a suitable, possibly adjustable, valve spring is provided. In addition, with a relay valve 124B , 124C advantageously a relay pressure limiter 123 of the relay valve 124B , 124C be provided, in which, while tapping the pressure, the section of the vent line on the compressed air supply side is located 6th the pressure for the relay valve 124B , 124C can be restricted. In this way, a certain variability or tolerance with regard to a pressure limitation can be achieved even at a comparatively high operating pressure.

As a difference between the cases of the indirectly piloted vent valve arrangements 120B , 120C it should be noted that, in any case, a regeneration throttle 63 at the compressed air supply system 10B can be selected larger than a regeneration throttle 63 at the compressed air supply system 10C ; the reason is that a main exhaust flow does not go through the control valve 126B to be led. In principle, this enables the compressed air to be vented or discharged from a pneumatic system more quickly 100B than with a pneumatic system 100C the case is. At the same time, the compressed air supply system is also used 10B adequate regeneration of the air dryer 60 adapting, preferably increasing, the nominal diameter of the venting throttle 64 achieved.

In a particularly advantageous manner, a pressure limiter 123 can be used for the control valves 126B , 126C the previously explained vent valve assemblies 120B , 120C Provide a flow-adjustable pressure limiter. This can be done with a de-energized closed vent valve arrangements 120B , 120C each designed as a solenoid valve control valve 126B , 126C have an adjustable opening pressure. Depending on requirements, a maximum pressure can be limited to a higher or lower value by setting a higher or lower current.

The present case is for a compressed air supply system formed according to the concept of the invention with a “rapidly venting, indirectly pilot-controlled vent valve arrangement” in FIG 2 , 3 and 4A / 4B a preferred embodiment according to the concept of the invention explained. These not only allow - like the embodiment in 1 B. - A quick venting with a comparatively increased vent valve nominal width, without the effort for actuating the vent valve with a solenoid control valve becoming too great. At the same time, for a compressed air supply system with a “normally ventilating, indirectly pilot-controlled vent valve arrangement”, the 1C in the 2 , 3 and 4A / 4B preferred embodiments according to the concept of the invention can be used and transferred as explained below.

Furthermore, in these particularly preferred embodiments according to the concept of the invention 2 , 3 and 4A / 4B a residual pressure remaining in the system is kept low in order to keep a risk associated with moisture or icing for the compressed air supply system, in particular the valves of the vent valve arrangement, low, and a measure has been taken to avoid the risk of icing. This can also be applied to a compressed air supply system with a “normally ventilating, indirectly pilot-controlled vent valve arrangement” 1C be transmitted.

The concept of the invention is hereinafter - generally applicable to indirectly piloted vent valve arrangements - using the particularly preferred embodiments of FIG 2 , 3 and 4A / 4B described in more detail.

2 shows, as mentioned in a non-limiting manner, a first preferred embodiment of the compressed air supply system with a “quickly venting, indirectly piloted vent valve arrangement”, which is further developed with a design of a vent valve that is advantageous according to the concept of the invention 124 as a relay valve with a control of the vent valve mentioned 124 by means of a control valve 126 as part of a vent valve assembly 128 . For this purpose - based on 1B and 1C -in any case, in some cases, identical reference numerals are used for the same parts or parts with the same function; for corresponding functional properties, analogous to the description of 1B referenced.

In particular, the 2 , 3 and 4A / 4B a pneumatic system 90 with a bellows 91 or a memory 96 represented symbolically. The pneumatic system 90 but especially as in 1A until 1C shown with several bellows 91 and at least one memory 96 preferably carried out at a gallery. Under a gallery 95 In this respect, any type of collecting line is to be understood in a very general way, from which branch lines to bellows 91 and save 96 or a line to the compressed air supply system 10 , 10 ' , 10 '' go off; this can also generally be a pressure line 130 include downstream in the filling direction at a compressed air connection.

In 2 it can also be seen that the vent valve assembly 128 with the pneumatic part the vent valve assembly 128 - namely, including the vent valve 124 in the form of the relay valve - in the vent line 6th is connected and to the magnetic part of the vent valve assembly 128 - namely comprising a solenoid valve in the form of the control valve 126 with the specified magnet 126.1 - is connected in the control pressure path 7.

The relay valve is in this respect to represent the vent valve 124 with a control connection 124.1 and a control mating connection 124.2 formed, both of which - as explained below - are connected to the control pressure path 7. That is, via the control pressure path 7 is a -in the embodiment of 2 from the main pneumatic line 5 - Branchable control pressure p both sides of an in 4B Relay piston K124 of the vent valve shown 124 can be supplied, i.e. the control connection 124.1 and the control counter connection 124.2 .

The control pressure path 7 is designed in the function of a feedback line, which has one in 4B shown control room GDR of the vent valve 124 pneumatically connects to a control room SDR of the vent valve 124 for guiding the control pressure p . The control connection 124.1 also has a control pressure supporting - i.e. acting in the same direction as the control pressure p - Valve spring 124 open.

The control pressure path 7 has a main control line for this purpose 110 between a main branch connection 78 on the main pneumatic line 5 and a branch connector 79. That is, in the embodiment of 2 is the main control line 110 between a main branch connection 78 on the main pneumatic line 5 and a main branch control line 112 to the control pressure receiver connection 126X of the control valve 126 formed, with a branch control line 111 on the main control line 110 connects. The main branch control line 112 starts from the branch connection 79 and connects directly to the control pressure receiver connection 126X of the control valve 126 at. The control pressure path 7 also has a branch control line 111 starting from the branch connection 79 of the main control line 110 to a control counter connection 124.2 of the vent valve 124 on.

• - eine Hauptzweig-Steuerleitung 112 an einem Steuerdrucknehmeranschluss 126X des Steuerventils 126 zur Zuführung des Steuerdrucks p zum Steuerdrucknehmeranschluss 126X, und
• - eine pneumatische Steuerrelaisleitung 120 an dem Steueranschluss 124.1 des Entlüftungsventils 124 zur Zuführung des Steuerdrucks p zum Steueranschluss 124.1 vom Steuerdruckgeberanschluss 126Y des Steuerventils 126, insbesondere zur Zuführung des Steuerdrucks p zum Steueranschluss 124.1 bei unbestromtem Steuerventil 126, und
• - eine Zweig-Steuerleitung 111 an dem Steuergegenanschluss 124.2 des Entlüftungsventils 124 zur Zuführung des Steuerdrucks p zum Steuergegenanschluss 124.2, insbesondere unterbrechungsfreien Zuführung des Steuerdrucks p zum Steuergegenanschluss 124.2.

Das Steuerventil 126 ist hier als ein 3/2-Wegeventil ausgebildet und weist auch einen Steuerdruckentlüftungsanschlusses 126Z auf, der zur Steuerentlüftungsleitung 3", Entlüftungsableitung 3' und dem Entlüftungsanschluss pneumatisch offen ist.The control pressure path 7 also has a pneumatic control relay line 120 in pneumatic connection with the control pressure transducer connection 126Y of the control valve 126 to the control connection 124.1 of the vent valve 124 and which is connected to this. The control valve 126 is in the control pressure path 7 in or between the main branch control line 112 and the control relay line 120 connected, namely with a control pressure sensor connection 126X for supplying the control pressure p to the control pressure transducer connection 126X of the control valve 126 and a control pressure transducer connection 126Y for supplying the control pressure p to the control connection 124.1 from the control pressure transducer connection 126Y of the control valve 126 . Ie the control pressure path 7 has:

• - a main branch control line 112 at a control pressure transducer connection 126X of the control valve 126 for supplying the control pressure p to the control pressure transducer connection 126X , and
• - a pneumatic control relay line 120 at the control connection 124.1 of the vent valve 124 for supplying the control pressure p to the control connection 124.1 from the control pressure transducer connection 126Y of the control valve 126 , especially for supplying the control pressure p to the control connection 124.1 with de-energized control valve 126 , and
• - a branch control line 111 at the control counter connection 124.2 of the vent valve 124 for supplying the control pressure p to the control counter connection 124.2 , in particular uninterrupted supply of the control pressure p to the control counter connection 124.2 .

The control valve 126 is designed here as a 3/2-way valve and also has a control pressure ventilation connection 126Z that to the control vent line 3 " , Exhaust vent 3 ' and the vent connection is pneumatically open.

In the in 2 The control pressure is the de-energized and first switching position shown p in control path 7 via the main branch control line 112 and the control relay line 120 to the control connection 124.1 of the vent valve 124 passed through and is there. The control pressure p is therefore in a first, de-energized switching state of the control valve 126 as in 2 shown via the pneumatic control relay line 120 at the control connection 124.1 of the vent valve 124 to and via the branch control line 111 at the control counter connection 124.2 of the vent valve 124 constantly on, with the main control line 110 and the branch control line 112 are free of separating valves or the like.

The relay valve as a vent valve shown here 124 is in a first switching state between the first vent valve connection 124X on the first part 6 of the vent line 6th and the second vent valve port 124Y on the second part 6 of the vent line 6th to the vent connection 3 pneumatically closed, in particular the vent line 6th Separated for a compressed air flow, i.e. the first part 6 is pneumatically separated from the second part 6, so that ventilation is prevented. The relay valve; so the vent valve 124 , is therefore without Energizing the control valve 126 in a non-venting position.

The control valve 126 is in the in 2 shown first switching state between a control pressure sensor connection 126X and a control pressure transducer connection 126Y to the control connection 124.1 pneumatically open, so that it is permeable, in particular, for a compressed air flow of a control pressure, as explained above, so that pressure is applied to the control connection 124.1 can be done.

This position of the vent valve 124 as a relay valve according to the in 2 The first switching state shown results from the counter-control connection 124.2 from the control connection 124.1 acting force of the control pressure p at the control connection 124.1 and the valve spring 124 .

The vent valve 124 also has a control connection 124.1 assigned in 4B shown control surface F124.1 with a larger area than one of the control counter connection 124.2 assigned counter control surface F124.2. The control surface D1 of the so far in 4B Relay piston K124 of the vent valve shown 124 is designed here to be comparatively large compared to the counter-control surface D2, which is designed as an annular surface. This means that the control pressure is already comparatively low p the force on the control side of the relay piston in addition to the spring force of the valve spring 124 is so predominantly large that even with the smallest control pressure p the vent valve 124 the vent line 6th separates; the vent valve 124 is therefore safely in a non-venting position when the control valve is not energized 126 . Ie the vent valve 124 is designed even below a residual pressure p , especially below 0.5 bar residual pressure p , with the spring force of the valve spring 124 at the spring-force-assisted control connection 124.1 for pneumatic interruption of the vent line 6th close, and above a residual pressure p , especially above 0.5 bar residual pressure p , without control pressure venting at the control connection 124.1 and on both sides of the vent valve 124 supplied control pressure p for pneumatic interruption of the vent line 6th close.

To do this is the vent valve 124 in a first switching state between the first vent valve connection 124X and the second vent valve port 124Y to the vent connection 3 pneumatically closed, namely the vent line 6th is for a compressed air flow separating, allowing a vent E. is prevented, the vent valve in the first switching state 124 is pressurized on both sides, in particular this can also be below a residual pressure p can be implemented with a valve spring 124 that supports spring force. The control valve 126 is in a first, de-energized switching state between a control pressure sensor connection 126X and a control pressure transducer connection 126Y to the control connection 124.1 pneumatically opened, namely allows a flow of compressed air, so that a flow of compressed air is possible around the control connection 124.1 of the vent valve 124 to pressurize and the vent valve 124 to transfer from a second switching state to the first switching state. If the control valve is not energized 126 on the magnet 126.1 the 3/2-way valve separates the control path 7 with the force of the control valve spring 126.2 against a vent.

When the control valve is energized 126 on the magnet 126.1 the 3/2-way valve opens the control path 7 against the force of the control valve spring 126.2 . I. E. the control valve 126 is then in a second switching state between a control pressure sensor connection 126X and a control pressure transducer connection 126Y and thus to the control connection 124.1 pneumatically non-permeable, in particular separated for a compressed air flow, so that compressed air is applied to the control connection 124.1 not possible.

The control relay line 120 is then at the control exhaust connection 126Z to the control vent line 3 '' open so that the control connection 124.1 is relieved of pressure. In other words, in a second, energized switching state, the control pressure path 7 is between the control pressure receiver connection 126X and the control pressure transducer connection 126Y to the control connection 124.1 pneumatically closed, namely separated for a compressed air flow, so that a compressed air flow is prevented to the control connection 124.1 of the vent valve 124 to vent and the vent valve 124 from the first switching state of the vent valve 124 in the second switching state of the vent valve 124 to be transferred with the bellows valve open 93 and thus at the control counter connection 124.2 applied control pressure p . That is, in a second switching state of the vent valve 124 this is between the first vent valve connection 124X and the second vent valve port 124 to the vent connection 3 pneumatically opened, namely opens the vent line 6th for a compressed air flow, so that a vent E. a bellows 91 with the bellows valve open 93 is possible, in particular wherein the control connection is in the second switching state 124.1 of the vent valve 124 is vented as explained.

In this case predominates when the bellows valve is open 93 those by control pressure p caused force on the relay piston at the control counter connection 124.2 ; ie practically only against the spring force of the vent valve-valve spring 124. The vent valve 124 will consequently from the in 2 The non-venting switch position shown is transferred into the venting switch position, against the spring force of the valve spring 124 of the vent valve 124 - This as a result of the force on the second control surface F124.2 of the relay piston K124 facing the counter control chamber GDR, as shown in FIG 4B is shown. The control pressure p is via the branch control line 111 the control counter connection 124.2 fed.

The vent line 6th like the control path 7, however, when the bellows valve is closed 93 can be completely vented via the throttle 63 , the air dryer 60 in regeneration direction; ie in the venting direction to the vent line 6th and into the vent 3 ' for ventilation 3 . The venting can take place down to a residual pressure of 0.1 bar and only when this residual pressure falls below 0.1 bar does the spring force of the valve spring 124 of the venting valve predominate 124 the one in the dual control line 111 remaining control pressure p , which at the control counter connection 124.2 is present. The smaller the valve spring 124 is designed, the lower the residual pressure remaining in the system p ; this can be below 0.5 bar.

With the control valve open to the environment 126 the vent valve assembly 128 with the bellows valve closed 93 Finally, the spring force of the valve spring 124 of the vent valve predominates 124 and closes the vent valve 124 again, making the vent line 6th is pneumatically separated. This means that due to the design of the control surfaces of the relay piston - D2 much smaller than D1 - the residual pressure remaining in the system can p be comparatively small compared to conventional compressed air supply systems, in which a vent valve closes much earlier due to the spring force against the control pressure in the control relay line.

On the other hand, when the compressor is in operation 21 a filling process can take place with the vent line closed 6th - The control pressure prevailing in the control pressure path 7 p can in principle be as high as desired; in the event of a faulty compressor output with a control pressure exceeding the maximum pressure p in the sense of an overpressure P. but would no longer be over the magnet even in the event of one 126 against the spring force of the valve spring 126.2 of the control valve 126 actuatable control valve 126 venting can take place as part of an overpressure function. An overpressure vent P. connects to the control pressure path 7; in the embodiment of 2 is this by means of a pressure limiter 126.3 is formed in the control valve 126 is integrated, with the pressure limitation 126.3 to the control valve 126 and the control pressure path 7 is pneumatically connected.

The control valve points to the overpressure function 126 in the embodiment of 2 the previously explained pressure limitation 126.3 on which to the main branch control line 112 and on the side of the magnet 126.1 of the control valve 126 connected; So even with existing valve icing of the control valve 126 becomes the control valve 126 against the spring force of the valve spring 126.2 open with overpressure P. in the pressure limitation 126.3 . That is to say, a pressure limiting element connected to the control pressure path 7, here in the form of the pressure limiter 126.3 is designed to vent an overpressure P. the control pressure path 7 and the vent line 6th to a vent outlet 3 ' to the vent connection 3 .

3 shows a particularly preferred second embodiment of a compressed air supply system 10 ' with a “rapidly ventilating, indirectly pilot-controlled vent valve arrangement”, which is also developed with a design of a vent valve that is advantageous according to the concept of the invention 124 as a relay valve with a control of the vent valve 124 with a control valve 126 as part of a vent valve assembly 128 . This is a relay piston on both sides of the vent valve 124 applied control pressure via practically the same control pressure path 7 as in the first embodiment of FIG 2 guided; therefore, the same reference numerals are used for the same parts or parts with the same function as in 2 used. The differences are explained below.

A modification provides that a system-internal memory, i.e. within the compressed air supply system 10 ' or - as here - one on the compressed air supply system 10 ' connected storage 96 , e.g. in the pneumatic system 90 with storage valve 97 , on a pressure pipe 130 is used as a pressure transducer. In the present case it is provided that the control pressure path 7 is on the pressure line 130 at the compressed air connection 2 is connected, in particular the control pressure path 7 is here on a gallery 95 ; namely on the pressure accumulator line 98 connected as this in 3 is shown. The embodiments according to the concept of the invention see a relay piston of the vent valve that is acted upon by control pressure on both sides 124 with the advantage that this makes the actuation of the relay valve easier and safer and can also use the system-internal memory. The pressure line is here for this purpose 130 part of the control pressure path 7 and runs between a main branch connection 78 in the filling direction downstream of the compressed air connection 2 and a main branch control line 112 to the control pressure receiver connection 126X of the control valve 126 - the main branch control line 112 is to the pressure line 130 connected to a first branch connection 79.1, with a branch Control line 111 on the main branch control line 112 is connected to a second branch connection 79.2. Ie the vent valve that can be pressurized on both sides 124 is here pressurized with a control pressure from the memory 96 . The function results in the same way as on the basis of 2 d described.

In the second embodiment of the compressed air supply system 10 ' In addition, the pressure limiting element is designed as an external pressure limiting element, namely designed as an external pressure limiting valve 125 in a pneumatic connection 6 ', which is the vent valve 124 bridged on the exhaust pressure side. The pressure limiting element is therefore not connected to the control pressure path 7, as in the first embodiment, but to the vent line 6th connected. The pressure limiting element is in the present case in one of the vent line 6th branching branch ventilation line 6 'for ventilation discharge 3 ' for ventilation 3 formed as a pressure relief valve 125. The pressure-limiting valve 125 is to be opened against the spring force of a valve spring 125.2 by applying line pressure to a pressure control connection 125.1 from the branch ventilation line 6 'upstream of the pressure-limiting valve 125 from the pressure limiter 125.3; ie for the flow through the branch ventilation line 6 'to the ventilation discharge line 3 ' for ventilation 3 . The additional ventilation line 6 'bridges the ventilation valve 124 in the vent line 6th from a first vent branch connection 76 in the vent line 6th to a second ventilation branch connection 77 in the ventilation discharge line 3 ' .

The external pressure-limiting element, here in the form of the pressure-limiting valve 125 in the branch ventilation line 6 'mentioned, works in this respect with a ventilation pressure level that is established via the ventilation valve 124 falls off.

4A shows a third embodiment of a compressed air supply system 10 " with a "fast venting, indirectly piloted vent valve arrangement", which - as in the embodiment of 2 - Is developed with a design of a vent valve that is advantageous according to the concept of the invention 124 as a relay valve with a control of the vent valve 124 with a control valve 126 as part of a vent valve assembly 128 . Please refer to the description of the 2 referenced with identical reference numerals.

In the present case, however, the pressure limiting element is a modification of the 2 no pressure limit 126.3 in the control valve 126 integrated like this in 2 is shown, but a pressure limiting element is provided as an internal pressure limiting valve 127 with pressure limiter 127.3 valve spring 127.2 and overpressure control connection 127.1. For this purpose, a pressure limiting element is designed as the internal pressure limiting valve 127 on the control pressure path 7, and the vent valve 124 is bridged on the control pressure side. In this case, a vent outlet 75 of the pressure-limiting element 127 is for venting off 3 ' to the vent connection 3 pneumatically connected and a pressure input 74 of the pressure limiting element 127 is connected to the pneumatic control relay line 120 pneumatically connected.

An overpressure resulting from a control pressure, possibly also residual pressure, is tapped off upstream of the pressure limiting valve 127; namely here the control pressure is tapped from a control relay branch line 120 'which branches off from the control relay line 120 to the vent line 3 , or ventilation discharge 3 ' , that is between a first and a second control pressure branch connection 74, 75. The overpressure function is possible when the control valve is de-energized 126 , ie when the control valve 126 in a first, de-energized switching state between a control pressure sensor connection 126X and a control pressure transducer connection 126Y to the control connection 124.1 is pneumatically opened, namely allows a flow of compressed air, so that a flow of compressed air is possible to the control connection 124.1 of the vent valve 124 to apply pressure or, in the case of the above-mentioned overpressure, the vent valve 124 to the extent to be bridged on the control pressure side and the control relay line 120 to vent. The internal pressure-limiting element in the form of the internal pressure-limiting valve 127 thus works with an overpressure on the control pressure side P. , which is in the control relay line 120 is applied, unlike the external pressure relief element in the form of the pressure relief valve 125, which has an overpressure on the venting pressure side P. which works in the section of the vent line 6th to the main line 5 is present. The control relay branch line 120 'bridges the vent valve, so to speak 124 on the control pressure side from branch connection 74 in front of the control connection 124.1 to branch connection 75 behind the vent valve connection.

The previously explained constructive training of the in 4A embodiment shown with the relay valve 124 as a vent valve is in 4B shown; the compressed air supply system is again with the same reference numerals 10 " shown, with the relay valve as a vent valve 124 , with an enlarged view of the relay piston K124 and the valve spring 124. The relay piston K124 supports the control connection 124.1 Associated control surface F124.1 with a larger area D1 compared to that designed as an annular surface Counter control surface F124.2 with a smaller area D2, which is connected to the counter control connection 124.2 assigned.

The nominal diameter D3 of the vent connection of the vent valve is also shown 124 in the vent line 6th ; i.e. the nominal size D3 between the first and the second vent valve connection 124X , 124Y . The corresponding control pressure chamber SDR and control back pressure chamber GDR is also shown. The relay piston K124 is designed as a differential piston and carries a seal SD on the control pressure chamber side and a counter control pressure side seal GD on the counter control pressure side, which on the relay piston K124 the counter control chamber GDR of the vent valve 124 pneumatically against a control room SDR of the vent valve 124 for guiding the control pressure p and seal the vent line. In the present case, the relay piston K124 is held on the valve seat S124 as a result of the spring force of the valve spring 124 and the control pressure and thus separates or closes the vent line 6th tightly against a venting process; for this purpose, a seat seal, not shown in detail, is provided on valve seat S124 and / or relay piston K124.

5 shows two flow charts, each to illustrate a process of ventilation B. or ventilation E. as with a preferred embodiment of the 2 , 3 or 4A , 4B can be realized.

For ventilation B. a bellows 91 an air spring 92 becomes the bellows valve 93 open and the compressor 21 conveyed to the main pneumatic line 5 Compressed air via the compressed air supply 1 with the vent valve closed 124 via the regenerable air dryer 60 and throttle 63 to the compressed air connection 2 .

The one from the main pneumatic line 5 Derived control pressure in the control pressure path 7 is on both sides of the vent valve 124 , ie at the control connection 124.1 and at the control counter connection 124.2 , so that, as explained above, it remains in the closed state.

The steps S1, S2 represent the filling of the control pressure path 7 with control pressure to the relay valve 124 , namely via a main control line 110 between a main branch connection 78 on the main pneumatic line 5 and a main branch control line 112 to the control pressure sensor connection 126A of the control valve 126 . In addition, at least one Bald valve or a pressure accumulator valve for a pressure accumulator is opened in step S1, S2 in order to fill the relevant bellows or the pressure accumulator via the main line.

In step S3 the vent valve remains 124 thus closed and the filling process can be completed by closing the bellows valve in step S4 and setting the filling B. of compressor operation.

The same applies to a venting process E. to stop compressor operation or not to switch it on and to vent a bellows 91 an air spring 91 becomes the bellows valve 93 opened so that compressed air passes through the throttle 63 the regenerable air dryer 60 to the vent line 6th regenerated, i.e. moisture adsorbed there in the vent line 6th wearing. The control pressure prevailing in the control pressure path 7 is used as a control valve when the 3/2-way valve is transferred 126 in the first de-energized switching state, in which there is between a control pressure transducer connection 126X and a control pressure transducer connection 126Y to the control connection 124.1 is pneumatically opened, on both sides of the vent valve designed as a relay valve 124 supplied as explained above.

By transferring the 3/2-way valve as a control valve 126 In the second and energized valve position, which is open for venting, in contrast to the first and de-energized switching position shown in the previous figures, however, the control pressure at the counter-control connection predominates 124.2 from the compressed air connection 2 , especially the pneumatic system 90 , is given. Steps S1 and S2 of venting E. provide the opening of the bellows valve 93 and opening the control relay line 120 for venting by moving the control valve 126 by actuating the solenoid of the control valve 126 represent.

Step S3 thus symbolizes the unilateral loading of the vent valve 124 at the control counter connection, 124.2 and thus the opening of the vent valve 124 in the vent line 6th , ie transferring the vent valve 124 into the second, open switch position.

A venting of both the control pressure path 7 and the vent line 6th can thus over the air dryer 60 take place, except for a residual pressure p which is comparatively low in the present case. Because this comparatively low residual pressure p is only limited downwards by the restoring force of the valve spring 124 of the vent valve, which is comparatively small here 124 against that comparatively low residual pressure at the control counter port 124.2 . As shown by way of example, this is given here by the force from the product of the control pressure on the surface D2 of the counter-control connection, which is designed here as an annular surface 124 .2 multiplied by this area D2 of the ring area. The opposite surface D1 of the control connection 124.1 is pressureless namely as a result of the - while in the energized state of the control valve 126 - via the relay piston control line 120 and the control pressure vent connection 126Z to the control vent line 3 '' pneumatically open control valve 126 .

Now the pressure drops p in the system below or at this residual pressure of 0.1 bar, for example, the control counterpressure on the control counter-port no longer predominates 124.2 , but the spring force of the valve spring 124 of the vent valve 124 and the vent valve 124 is in step S4 again in a closed, that is, the vent line 6th divisive position transferred. Alternatively, the vent E. be terminated by the control valve 126 is no longer energized and the control valve 126 is transferred to the first, de-energized switch position. In the first, de-energized switch position, the control pressure transducer connection 126A becomes the control pressure transducer connection again 126B switched through, reducing the pressure of the main line 5 again at the control connection 124.1 of the vent valve 124 is present.

How out 4B the vent valve ( 124 ) one to the control connection 124.1 associated control surface F124.1 with a larger area D1 than one of the control counter connection 124.1 associated counter control surface F124.2 with a smaller surface D2. In addition, the vent valve 124 one through the first and second vent valve ports 124X , 124Y in the vent line ( 6th ) has arranged ventilation cross-section, the area D0 of which is smaller than that of the control connection 124.1 assigned control surface F124.1 and is smaller than that of the control counter connection 124.2 assigned counter control surface F124.2.

Without power to the control valve, due to the larger area D1 on the control pressure side compared to the smaller area D2 on the control pressure side of the vent valve, with the same control pressure on the control pressure side and control pressure side, a greater force acts on the relay piston of the vent valve from the control pressure side; this also with the support of the valve spring of the vent valve; this is therefore closed without current when the control pressure is applied and separates the vent line so that venting is prevented.

The venting process is completed by closing the bellows valve 93 in step S5 and is ended, the compressor - as before - is not actuated.

Should the air dryer 60 be vented at least to the residual pressure, then the bellows valve 93 close beforehand, so that the pressure in the main line 5 and in the air dryer through the control valve that is still energized 126 and the open vent valve 124 is vented at least approximately to the residual pressure. Subsequently or after a predetermined time, the control valve is switched to be de-energized and transferred to the first, de-energized switch position described above.

Particularly in the case of an overpressure situation, a pressure limiting element in the form of an external or internal pressure limiting valve 125, 127 can control the pressure in the control pressure path or in the vent line 7, 6 - the vent valve 124 Bridging - on the vent line side or on the control pressure side for venting discharge 3 ' dissipate.

6th shows a schematic representation of a vehicle 1000 - present in the form of a car 1001 - having a pneumatic system 100 with a compressed air supply system 10 , 10 ' , 10 " according to the concept of the invention and one as an air suspension system 90.1 trained pneumatic system 90 .

In particular in vehicles in the passenger car sector, only relatively small amounts of compressed air are often required for level control during operation, since only small differences in height have to be managed with the air suspension system in normal operation. The car vehicle shown here as an example, without restriction of applicability also for trucks or other commercial vehicles 1000 has four wheels 920, of which the two wheels assigned to one side of the vehicle are shown here due to the sectional view. The air suspension system has the same number of wheels 90.1 via four air springs 92 , of which the two bellows assigned to one side of the vehicle are here analogous to the wheels due to the sectional view 91 are shown. The four air springs 92 , which are each assigned to the four wheels 920, are part of the air suspension system 90.1 from the compressed air supply system 10 supplied with compressed air. The compressed air supply system 10 comprises an air dryer assembly 220 according to the concept of the invention and is via the supply line 5 ' a pneumatic main line not shown in detail here 5 , a gallery connection 2 ' , a valve block 20th and a gallery 95 with the components of the pneumatic system 90 , in this case the four air springs 92 , pneumatically connected. The compressed air supply system 10 also has a control unit 750 in the form of an Electronic Control Unit (ECU), which is used to control the in the compressed air supply system 10 , 10 ' , 10 " Existing components is used, in particular the air compressor, not shown here, or the vent valve arrangement. The control unit 750 can also control further components of the pneumatic system 100 control, especially the valve block 20th .

List of reference symbols

10, 10 ', 10 ", 10A, 10B, 10C

Compressed air supply system

0

Air supply

1, 2

Compressed air supply, compressed air connection

3rd

Vent connection

5

Pneumatic main line, compressed air supply line

6th

Vent line

2 '

Gallery connection

3 '

Vent discharge

3 "

Control vent line

5 '

supply line

48, 49

check valve

63, 64

Regeneration throttle / throttle, venting throttle

63.1, 63.2, 63.3

Regeneration chokes

60

Air dryer

20th

Valve block

90, 90.1

Pneumatic system, air suspension system

91

bellows

92

Air spring

93

Solenoid valve in front of bellows, bellows valve

94

Solenoid valve in front of pressure accumulator, pressure accumulator valve

95

gallery

96

Pressure accumulator

97

Air suspension line

98

Accumulator line

1000

vehicle

100, 100A, 100B, 100C

pneumatic system

p

Control pressure, residual pressure

P.

Overpressure

110

Main control line

111

Branch control line

112

Main branch control line

120

pneumatic control relay line

130

Pressure line at the compressed air connection

66, 68

filter

21

Air compressor, compressor

86

Control connection

BV, B

Filling process

E.

Venting process

PA

Shutdown pressure

123

Pressure limiter

122A

magnetic valve

128, 120A, 120B, 120C

Vent valve assembly, solenoid valve assembly

126

Control valve

126B, 126C

Control valve

124B, 124C

Relay valve as a vent valve

124

Vent valve

124.1, 124.2

Control connection, control counter connection of the vent valve

124X, 124Y

first and second vent valve connection in the vent line 6th

126.1

magnet

126.2

Valve spring

126.3

Pressure limitation

126X

Control pressure sensor connection of the control valve

126Y

Control pressure transducer connection of the control valve

126Z

Control pressure exhaust connection

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102012001736 A1 [0008]
• DE 102014009419 [0009, 0063]
• WO 2016/026577 [0010]
• DE 102014012608 A1 [0011]
• WO 2016/026577 A1 [0075]

Claims (20)

Compressed air supply system (10, 10 ', 10 ") for operating a pneumatic system (100), comprising: - a compressed air supply (1), a compressed air connection (2) to a pneumatic system (90) and a ventilation connection (3) to the environment, - a Pneumatic main line (5) between the compressed air supply (1) and the compressed air connection (2), in which an air dryer (60) is connected, and - a ventilation line (6) to the ventilation connection (3), which runs between the compressed air supply (1) and the Air dryer (60) is connected to the main pneumatic line (5), a vent valve (124) connected via a first and a second vent valve connection (124X, 124Y) being connected in the vent line (6), - a control pressure path (7) with an im Control pressure path (7) connected control valve (126) as part of a vent valve arrangement with the control valve (126) and the vent valve (124), wherein - the vent valve (124) as a Rel aisventil is formed with a control connection (124.1), which is pneumatically connected to the control valve (126) via the control pressure path (7) to act on the control connection (124.1) with a control pressure (p) which can be branched via the control pressure path (7), characterized in that that - the control pressure (p) can be supplied via the control pressure path (7) on both sides of the vent valve (124), namely by means of the control valve (126) to the control connection (124.1) and without interruption to the control counter connection (124.2) of the vent valve (124). Compressed air supply system (10, 10 ', 10 ") according to Claim 1 , characterized in that the control pressure (p) can be applied to a relay piston (K124) of the vent valve (124) via the control connection (124.1) and the control counter connection (124.2), the control pressure (p) via the control pressure path (7) on both sides of the Relay piston (K124) of the vent valve (124) can be fed. Compressed air supply system (10, 10 ', 10 ") according to Claim 1 or 2 , characterized in that the control pressure path (7) is connected to the main pneumatic line (5), in particular is connected to the main pneumatic line (5) between the air dryer (60) and the compressed air connection (2). Compressed air supply system (10, 10 ', 10 ") according to Claim 1 or 2 , characterized in that the control pressure path (7) is connected to a pressure line (130) on the compressed air connection (2), in particular is connected to a gallery (95) or to a pressure accumulator line (98). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 4th , characterized in that the control pressure path (7) has: - a main branch control line (112) on a control pressure sensor connection (126X) of the control valve (126) for supplying the control pressure (p) to the control pressure sensor connection (126X), and / or - a pneumatic Control relay line (120) at the control connection (124.1) of the vent valve (124) for supplying the control pressure (p) to the control connection (124.1) from the control pressure transmitter connection (126Y) of the control valve (126), in particular for supplying the control pressure (p) to the control connection (124.1) ) when the control valve (126) is de-energized, and / or - a branch control line (111) at the control counter connection (124.2) of the vent valve (124) for supplying the control pressure (p) to the control counter connection (124.2), in particular uninterrupted supply of the control pressure (p ) to the control counter connection (124.2). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 5 , characterized in that - a pressure limiting element (126.3, 127) connected to the control pressure path (7) is formed, a venting of the control pressure path (7), in particular a residual pressure (p) and / or overpressure (P) of the control pressure path (7), to effect, in particular a vent to a vent line (3 ') to the vent connection (3). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 6th , characterized in that the control connection (124.1) of the vent valve (124) is assigned a spring force-supporting valve spring (124.3) such that a spring force of the valve spring (124.3) in the direction of a pneumatic force at the control connection (124.1) and / or against a direction of a pneumatic force at the control counter connection (124.2) acts. Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 7th , characterized in that the vent valve (124) is designed, - in the case of control pressure venting at the control connection (124.1), in particular when the control valve (126) is energized, and against a spring force of the valve spring (124.3) at the spring-force-assisted control connection (124.1), the vent line ( 6) open pneumatically for venting and / or - below a residual pressure (p), in particular below 0.5 bar residual pressure (p), with the spring force of the valve spring (124.3) at the spring-assisted control connection (124.1) for pneumatic interruption of the vent line (6) to close, and / or - above a residual pressure (p), in particular above 0.5 bar residual pressure (p), without closing a control pressure vent at the control connection (124.1) and when the control pressure (p) is supplied to both sides of the vent valve (124) to pneumatically interrupt the vent line (6). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 8th , characterized in that the control pressure path (7) has: - a main control line (110) between a main branch connection (78) on the main pneumatic line (5) and a main branch control line (112) to the control pressure sensor connection (126X) of the control valve (126), in particular wherein a branch control line (111) connects to the main control line (110) and / or - a pressure line (130) between a main branch connection (78) in the filling direction downstream of the compressed air connection (2) and a main branch -Control line (112) to the control pressure receiver connection (126X) of the control valve (126), which is connected to the pressure line (130) (79.1), a branch control line (111) being connected to the main branch control line (112) (79.2 ). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 9 , characterized in that a pressure limiting element - is designed as an internal pressure limiting valve (127) on the control pressure path (7), and bridges the vent valve (124) on the control pressure side, a vent outlet (75) of the pressure limiting element (127) for venting discharge (3 ') to the Vent connection (3) is pneumatically connected and a pressure input (74) of the pressure limiting element (127) is pneumatically connected to the pneumatic control relay line (120), and / or - is designed as a pressure limiter (126.3) which is integrated in the control valve (126) , the pressure limiter (126.3) being pneumatically connected to the control valve (126) and the control pressure path (7). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 10 , characterized in that - the vent valve (124) is pneumatically closed in a first switching state between the first vent valve connection (124X) and the second vent valve connection (124Y) to the vent connection (3), namely separates the vent line (6) for a compressed air flow, so that a venting (E) is prevented, in particular wherein in the first switching state the venting valve (124) is pressurized on both sides, in particular below a residual pressure (p) with a spring force-supporting valve spring (124.3), and - in a second switching state of the venting valve (124) between the first vent valve connection (124X) and the second vent valve connection (124X) to the vent connection (3) is pneumatically opened, namely the vent line (6) opens for a compressed air flow, so that a vent (E) is possible, in particular with the control connection in the second switching state (124.1) of the vent valve (124) is vented. Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 11 characterized in that - the control valve (126) is pneumatically opened in a first, de-energized switching state between a control pressure sensor connection (126X) and a control pressure sensor connection (126Y) to the control connection (124.1), namely allows a compressed air flow so that a compressed air flow is possible around the To apply pressure to the control connection (124.1) of the vent valve (124) and to transfer the vent valve (124) from the second switching state to the first switching state; and - in a second, energized switching state between the control pressure transducer connection (126X) and the control pressure transducer connection (126Y) to the control connection (124.1) is pneumatically closed, namely separates for a compressed air flow, so that a compressed air flow is prevented to open the control connection (124.1) of the vent valve ( 124) and to move the vent valve (124) from the first switching state of the vent valve (124) to the second switching state of the vent valve (124). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 12th , characterized in that the relay piston (K124) has a first control surface (F124.1) facing a control chamber (SDR) and a second control surface (F124.2) facing a counter control chamber (GDR), wherein - the first and the second control surface (F124.1, F124.2) are arranged for receiving a control pressure and a control counterpressure directed against one another, which are derived from the control pressure path (7). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 13th , characterized in that - the vent valve (124) has a control surface (F124.1) assigned to the control connection (124.1) with a larger area (D1) than a counter-control surface (F124.2) assigned to the counter-control connection (124.1) with a smaller area (D2) ) and / or - the vent valve (124) one via the first and the second vent valve connection (124X, 124Y) has a vent cross section arranged in the vent line (6), the area (D0) of which is smaller than the control area (F124.1) assigned to the control connection (124.1) and smaller than the counter control area (F124.2) assigned to the control counter connection (124.2). Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 14th , characterized in that the vent valve (124) has a relay piston (K124) that can be pressurized with control pressure for switching the vent valve (124) into an open or closed switching state, the control pressure (p) at the control connection (124.1) from the control valve (126) is switchable and the control pressure (p) at the control counter connection (124.2) from the compressed air supply (1), in particular the air compressor (21), or the compressed air connection (2), in particular the pneumatic system (90), is specified. Compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 15th , characterized in that the control valve (126) is a 3/2-way valve and the vent valve (124) is a 2/2-way valve, which are connected to the vent line (3 ') to the vent connection (3), namely the 3 / 2-way valve via a control vent line (3 ") and the vent valve (124) via the vent line (6). Compressed air supply system (100) with a compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 16 characterized in that with a pneumatic system (90), in particular an air suspension system of a vehicle, preferably a passenger vehicle, in particular having a gallery (95), the at least one branch line (98, 99) pneumatically connected to the gallery (95) with a bellows ( 91) and / or an accumulator (92) and a directional valve (93) arranged upstream of the bellows and / or the accumulator. Vehicle (1000) with a compressed air supply system (100) after Claim 17 . Method for operating a compressed air supply system (10, 10 ', 10 ") according to one of the Claims 1 until 15th , characterized in that in the process the control pressure (p) is fed via the control pressure path (7) on both sides of the vent valve (124), namely by means of the control valve (126) to the control connection (124.1) and without interruption to the control counter connection (124.2) of the vent valve ( 124) is supplied. Procedure according to Claim 19 , wherein for operating a compressed air supply system (100) according to Claim 17 , the method comprises the following steps: - Filling the pneumatic system (90), the vent valve (124) being pneumatically closed in a first switching state between the first vent valve connection (124X) and the second vent valve connection (124Y) to the vent connection (3), namely the The vent line (6) for a compressed air flow separates, so that venting (E) is prevented, in particular wherein in the first switching state the vent valve (124) is pressurized on both sides, in particular below a residual pressure (p) with a valve spring (124.3) supporting spring force, - venting (E) the pneumatic system (90), wherein in a second switching state of the vent valve (124) between the first vent valve connection (124X) and the second vent valve connection (124X) to the vent connection (3), namely the vent line (6) for a Compressed air flow opens so that venting (E) is possible h, in particular the control connection (124.1) of the vent valve (124) being vented in the second switching state.

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