EP4605285A1

EP4605285A1 - Pneumatic device having a one-way valve and an additional exhaust path with a sealing device

Info

Publication number: EP4605285A1
Application number: EP22808935.5A
Authority: EP
Inventors: Aleksander Fila; Ingo Fuhrmann; Guoguang Qiu; Karl-Heinz Riediger-Janisch; Pawel Wysocki
Original assignee: ZF CV Systems Europe BV; ZF Commercial Vehicle Systems Qingdao Co Ltd
Current assignee: ZF CV Systems Europe BV; ZF Commercial Vehicle Systems Qingdao Co Ltd
Priority date: 2022-10-17
Filing date: 2022-10-17
Publication date: 2025-08-27
Also published as: WO2024082082A1; CN120076967A

Abstract

The invention relates to a pneumatic device (1) for a vehicle (200), comprising: a primary exhaust path (17) for exhausting a pressure-carrying section along a exhaust direction (R); a one-way valve (19) in the primary exhaust path (17) to enable exhaust pressure in the pressure-carrying section (15) exceeding a pre-determined exhaust pressure threshold; a secondary exhaust path (21) for ex-hausting a residual pressure from the pressure-carrying section (15); and a sealing device (23) in the secondary exhaust path (21) adapted to switch at least between a normal state (Z1) and a sealing state (Z2). In the normal state the secondary exhaust path (21) can be flowed through and in the sealing state (Z2) the secondary exhaust path (21) is sealingly blocked. The invention further relates to a pneumatic brake system and a method for exhausting a pressure-carrying section of a pneumatic device.

Description

pneumatic device having a one-way valve and an additional exhaust path with a sealing device

TECHNICAL FIELD

The present invention relates to a pneumatic device for a pneumatic brake sys-tem of a vehicle and a pneumatic brake system having such a pneumatic device. The present invention further relates to a method for exhausting a pressure-carrying section of a pneumatic device.

BACKGROUND

In particular, pneumatic devices of the type mentioned above may be used in pneumatic brake systems for vehicles, especially for commercial vehicles, e.g. brake valves and/or relay valves therefor. Said pneumatic devices typically have pneumatic connections to the environment of the pneumatic device, for example, to exhaust excess pressure from a pressure-carrying section of the pneumatic device. However, such a pneumatic connection to the environment of the pneumatic device may allow foreign media located in the environment to enter the pneumatic device.
Frequently, pneumatic devices of the type described above are used in envi-ronments where various foreign media may be present. In particular, pneumatic brake devices and their components, such as relay valves, may be exposed to water from their environment, for example, during cleaning and operation in or after rain, flooding or deliberate fording of bodies of water. In particular, the in-gress of liquids, such as water, can impair the functionality of the pneumatic device. In the case of pneumatic brake systems, for example, ingress of foreign media, especially water, can lead to corrosion or, for example, to complete fail-ure of the brake system as a result of water freezing. Measures must therefore be taken to make the unintentional ingress of foreign media more difficult or, at best, to prevent it.
In the prior art, pneumatic devices with sealing devices are known that are de-signed to prevent the unintentional ingress of small amounts of spray water or water below a certain level.
Among others, DE 10 2020 108 757 A1 discloses such a pneumatic device hav-ing an exhaust path for exhausting a pressure-carrying section of the pneumatic device along an exhaust direction and a sealing device arranged in the exhaust path. The sealing device is provided by a sealing seat and a ball-shaped sealing body guided in a cage. The sealing seat is defined by the inner diameter of the exhaust passage and the ball-shaped sealing body is dimensioned accordingly. The sealing body is buoyant on water and arranged downstream the sealing seat in the outflow direction. In case of water ingress, the sealing body is floated against the sealing seat thereby sealingly blocking the exhaust path.
Furthermore, CN213619717U relates to a utility model, which discloses a me-chanical device in an exhaust path to prevent water ingression.
The described sealing device may provide a protection against water ingress but also may cause vibrations due to the oscillating ball-shaped sealing body. This may however have to prevented.
Furthermore, since exhaust via the exhaust path needs to fulfill exhaust time requirements, the diameter of the exhaust path is comparatively large and thus the diameter of the sealing body accordingly. In consequence, the oscillation of the comparatively large sealing body causes disruptive noise. Thus, there is a need to reduce (or further reduce) the noise level and oscillation of the pneu-matic device and further improve the protection against water ingress.
SUMMARY
In that regard, the object of the present invention is to enable a safe operation of a pneumatic device of the type described at the outset even in environments in which water ingress from e.g., the bottom side of the pneumatic device is prevalent.
In a first aspect, the object is solved by a pneumatic device according to claim 1. In particular, the object is solved by a pneumatic device comprising a primary exhaust path for exhausting a pressure-carrying section of the pneumatic de-vice along a exhaust direction and a one-way valve arranged in the primary ex-haust path which is configured to enable exhaust of the pressure-carrying sec-tion along the exhaust direction in case the pressure in the pressure-carrying section exceeds a predetermined exhaust pressure threshold. The pneumatic device according to the invention further comprises a secondary exhaust path for exhausting a residual pressure from the pressure-carrying section along the exhaust direction and a sealing device arranged in the secondary exhaust path. The sealing device is adapted to switch at least between a normal state and a sealing state, wherein in the normal state of the sealing device, the secondary exhaust path can be flowed through in the exhaust direction and in the sealing state of the sealing device, the secondary exhaust path is sealingly blocked at least in a direction opposite the exhaust direction. In other words, the pneumatic device has a primary exhaust path defining a main exhaust path for meeting the response exhaust time requirements which is protected against the environment by a one-way valve arranged in said primary exhaust path. The residual pres-sure below the predetermined exhaust pressure threshold on the other hand cannot be exhausted via said one-way valve and remains in the pressure-carrying section if not exhausted otherwise. For that reason, the pneumatic de-vice according to the invention further has the secondary exhaust path for ex-hausting the residual pressure and for balancing the pressure in the pressure carrying section with the atmospheric pressure. Said secondary exhaust path may be defined by a flow path extending through the pneumatic device or by a balancing port or a at least a small gap allowing the residual pressure to be bal-anced with the atmosphere. However, the secondary exhaust path is configured for allowing pressurized air below the pressure value necessary to open the one-way valve to be exhausted. Since also said secondary exhaust path has to be protected against an undesired ingress of medium, a sealing device is ar-ranged in said secondary exhaust path accordingly. In the absence of exhaust response time requirements for said secondary exhaust path, the second path may preferably have a smaller cross section than the cross section of the prima-ry exhaust path.
Since the residual pressure does not have to be exhausted via the primary ex-haust path, the one-way valve securely remains closed as long as the pressure in the pressure-carrying section is below the predetermined exhaust pressure threshold. As a consequence, in one aspect, the one-way valve is less prone to be affected by oscillations due to pressure changes or simply due to flow of the pressurized air in the pressure-carrying section of the pneumatic device.
It should be understood that the exhaust direction generally defines a direction from a pressure carrying section of the pneumatic device to the environment. The air may be exhausted in the exhaust direction via different exhaust paths or port.
Preferably, the sealing device is adapted to block the secondary exhaust path in the exhaust direction and opposite the exhaust direction in the sealing state.
Preferably, the sealing device is adapted to change from the normal state to the sealing state in case a liquid in the secondary exhaust path exceeds a threshold level. The threshold level may be determined such that the presence of a for-eign medium at or below the threshold value defines normal operation condi-tions of the pneumatic device. The presence of foreign medium above the threshold level defines the special operation conditions in which the pneumatic device may be exposed to water from their environment, for example, during cleaning, operation in or after rain, or flooding. Thus, it is ensured that the seal-ing device reliably changes to the sealing state in said special operating condi-tions. In particular, the foreign medium is water. In the following, the term “water” is also to be understood to include aqueous liquids and mixed fluids that pre-dominantly or to a large extent contain water, such as mud, bog or marsh water.
Preferably, the sealing device comprises a sealing body and a sealing seat, wherein the sealing body is configured to rest in a sealing manner against the sealing seat in the sealing state. Preferably, the sealing body is adapted to be buoyant in water. If the sealing body is buoyant in water, or another foreign me-dium, i.e. it represents the principle that the upward force exerted by water on the sealing body exceeds gravitational force. For example, the sealing body comprises a Polymer, in particular Polyoxymethylene (POM) .
Preferably, the sealing seat is facing downstream in the exhaust direction and the sealing body is arranged downstream of the sealing seat in the exhaust di-rection. Thus, the sealing body advanced by a force directed opposite the ex-haust direction towards the sealing seat to sealingly block the secondary ex-haust path.
In a preferred embodiment, the sealing body rests at a first position in the nor-mal state and moves to a second position in the sealing state. In said first posi-tion, the sealing body is positioned such that the exhaust air flow via the sec-ondary exhaust path is permitted, and remains in the normal state as long as no ingression of water into the pneumatic device has occurred. In the second posi-tion, even after the ingression of water into the pneumatic device, it is ensured that the sealing body prevents rising of the level of water within the pneumatic device above a certain level or for instance, above the level of the sealing body. In order to bring the sealing body into the second position, the sealing body is moved from an abutment surface on a bottom side of the sealing body to the sealing seat on an upper side of the sealing body. It is noted that in the second position, the exhaust air flow via the primary exhaust path is still possible, wherein the secondary flow path is sealingly blocked by the sealing body.
Preferably, the sealing seat or a section thereof has a normal in the exhaust direction that has at least one component that is parallel and equidirectional to the exhaust direction in the area of the sealing device. In other words, the scalar product between this normal and the exhaust direction in the region of the seal-ing device is greater than zero.
It is further preferred, that said sealing device further comprises a retaining part arranged downstream of the sealing body in the exhaust direction, wherein the sealing body rests at the retaining part in the first position in the normal state. In other words, the retaining part is arranged to hold the sealing device in the first position and prevent the sealing body from falling down through the secondary exhaust path in the exhaust direction. In accordance with an embodiment, the retaining part includes the bottom side abutment surface referred above. Pref-erably, the retaining path is attached to the piston by means of a snap connec-tion. The abutment surface is preferably facing towards the sealing seat to abut the sealing body, wherein the entrance to the exhaust channel is provided in said abutment surface. In the normal state, the sealing body rests at the abut-ment surface of the retaining part in the first position. At said first position, the sealing body partly overlaps the entrance to the exhaust channel. The residual pressure can flow around the sealing body into the exhaust channel via the part of the entrance to the exhaust channel that is released by the sealing body.
Preferably, the retaining part has an exhaust channel extending in the exhaust direction. Further preferred, the exhaust channel at least partly defines the sec-ondary exhaust path. The exhaust channel extending in the exhaust direction is preferably in fluid communication with the environment. Thus, water and other medium present in the environment will be guided through said exhaust channel to the sealing body and will meet the sealing body at a predefined position where water or other medium is blocked from moving any further. Thus, the threshold level can be easily calculated.
Preferably, the secondary exhaust path is at least partly defined by the one-way valve. Thus, the exhaust direction and the exhaust direction extend parallel at least in the region of the one-way valve. It should be understood that the sec-ondary exhaust path might also extend through the one-way valve. Thus, a more compact arrangement of the pneumatic device is provided.
In a preferred embodiment, the one-way valve comprises a valve seat, a mova-ble piston configured to selectively rest against the valve seat in a closed state of the one-way valve and a spring configured to advance the piston towards the valve seat. The spring force of the spring advancing said piston thus defines the pressure threshold.
Preferably, the piston at least partly defines the secondary exhaust path. In par-ticular, the secondary exhaust path extends through the piston. Thus, a more space-saving arrangement is provided.
It is further preferred, that the piston has a receiving space and the sealing de-vice is arranged in the receiving space. Thus, the sealing device can effectively block the secondary exhaust path extending preferably through the piston.
Preferably, the one-way valve further has a valve guide comprising the valve seat which is configured to at least partly receive the movable piston. Preferably, the valve guide has a low friction surface guiding the piston. As a result, the pis-ton is reliably guided and positioned within the pneumatic device. Since the valve guide comprises the valve seat, a more compact arrangement of the one-way valve is provided allowing a repeatable movement of the piston.
Preferably, the piston has a number of ribs configured for aligning the piston in the primary exhaust path. Preferably, the ribs are configured for aligning the piston in the valve guide defining a part of the primary exhaust path. Thus, the alignment of the piston is improved and undesired oscillations are reduced.
Preferably, the piston has a sealing member configured to sealingly rest at least against the valve seat in the closed state of the one-way valve. Preferably, said sealing member comprises a rubber. Thus, the sealing member improves the sealing of the first exhaust path in the closed state. A rubber provides sufficient sealing properties and durability even in challenging environments. It is pre-ferred, that the sealing member is attached to the piston by a positive-fit. In par-ticular, the sealing member is formed as a sealing ring and the piston has a groove corresponding to said sealing ring, wherein the sealing ring is received in said groove.
Preferably, the sealing member at least partly extends along the piston. In par-ticular, said sealing portion comprises an elastomer layer extending along the piston. Suitable sealing materials in general have a low stiffness and thus pro-vide sufficient damping properties.
Preferably, the piston also includes a damping member with a rubber. The damping member may preferably be provided between an upper section of the piston and the valve guide. The elastomer layer in accordance with an embodi-ment of the present invention is configured to dampen the oscillatory move-ments experienced by the piston when the exhaust air passes through e.g., the primary exhaust path. It is preferred, that the damping member is attached to the piston by a positive-fit. In particular, the damping member comprises one or more O-rings received in a corresponding groove of the piston.
Preferably, the sealing device is adapted to sealingly block the secondary ex-haust path in the sealing state in a direction opposite the exhaust direction and to enable flow through the secondary exhaust path in the exhaust direction in the normal state. Thus, even in environments in which a liquid level is above a predetermined threshold level, the exhaust of residual pressure is still enabled while at the same time of preventing ingression of the liquid.
In a second aspect, the invention relates to a brake system comprising a pneu-matic device according to the first aspect of the invention. By having such a pneumatic device, brake system participates from the advantages described above with regard to the pneumatic device. Thus, the preferred embodiments and benefits of the pneumatic device according to the first aspect are at the same time preferred embodiments and benefits of the brake system according to the second aspect. Thus, reference is made to the above description of the pneumatic device according to the first aspect of the invention, in particular, to the dependent claims. Preferably, the pneumatic device of the brake system is a brake valve arrangement of the brake system.
According to a third aspect of the invention, the above stated problem is solved by a method for exhausting a pressure-carrying section of a pneumatic device, in particular of a pneumatic device according to the first aspect of the invention, comprising the steps:
a) providing a one-way valve in a primary exhaust path, wherein the one-way valve is configured to enable exhaust of the pressure-carrying section along a exhaust direction in case the pressure in the pressure-carrying section exceeds a predetermined pressure threshold;
b) exhausting the pressure-carrying section along the exhaust direction via the one-way valve in case the pressure in the pressure-carrying section ex-ceeds a predetermined pressure threshold;
c) providing a sealing device in a secondary exhaust path adapted to switch at least between a normal state and a sealing state;
d) exhausting a residual pressure being below the predetermined pressure threshold from the pressure-carrying section via the sealing member along a exhaust direction; and
e) preventing fluid ingress into the secondary exhaust path by switching the sealing device from a normal state to a sealing state.
It should be understood that the method incorporating the exhaust of the pres-sure-carrying section along a exhaust direction via a one-way valve and ex-hausting the residual pressure along the exhaust direction via a sealing member as described with regard to the first aspect of the invention has similar or equal aspects as the first aspect of the invention, in particular as they are described in the dependent claims. Thus, reference is made to the above description of the pneumatic device according to the first aspect of the invention.
Preferably, step e) comprises providing fluid above a threshold level in the sec-ondary exhaust path of the pneumatic device, and moving the sealing device from the normal state to the sealing state. In the normal state of the sealing de-vice, a secondary exhaust path can be flowed through in a exhaust direction and the secondary exhaust path is sealingly blocked at least in a direction op-posite the exhaust direction in the sealing state of the sealing device.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:
Fig. 1 shows a schematic layout of a vehicle having a brake system comprising a pneumatic device according to the invention;
Fig. 2a shows schematic a pneumatic device according to a first embodi-ment of the invention;
Fig. 2b shows schematic a pneumatic device according to a second em-bodiment of the invention;
Fig. 2c shows schematic a pneumatic device according to a third embod-iment of the invention;
Fig. 3 shows a sectional view of a pneumatic device according to the invention in a normal state; and
Fig. 4 shows a sectional view of a pneumatic device according to the invention in a exhaust state.

DETAILED DESCRIPTION

A vehicle 200, as shown in Fig. 1, in particular a commercial vehicle, comprises a front axle 204 and a rear axle 206. For braking front wheels 208.1, 208.2 of the front axle 204 and rear wheels 210.1, 210.2 of the rear axle 206, the vehi-cle 200 may comprise a brake system 100 having a front axle brake circuit 102 for braking the front wheels 208.1, 208.2 and a rear axle brake circuit 104 for braking the rear wheels 210.1, 210.2. For braking the wheels 208.1, 208.2, 210.1, 210.2, the brake system 100 comprises front axle brake actuators 106.1, 106.2 and rear axle brake actuators 108.1, 108.2. The front axle brake actuators 106.1, 106.2 are connected to a front axle brake modulator 110 while the rear axle brake actuators 108.1, 108.2 are connected to a rear axle brake modulator 112. For providing compressed air at a supply pressure, the brake system 100 comprises a compressed air supply 114. Of course, it may comprise more than one air supply.
In order to brake the vehicle 200 a brake pressure needs to be supplied, in par-ticular to the front axle brake modulator 110 and the rear axle brake modula-tor 112. For providing the brake pressure, the brake system 100 comprises the pneumatic device 1 (see Figs. 3 and 4) . In the embodiment shown in Fig. 1, the pneumatic device 1 is a brake valve arrangement 10.
The brake valve arrangement 10 comprises a lower housing 2 having a supply connection 7, a working connection 9, and an exhaust portion 12. The exhaust portion 12 comprises a exhaust path 15 (see Figs. 2 to 5) . The supply connec-tion 7 is connected to the compressed air supply 114 via supply line 120.1 for receiving pressurized air at the supply pressure.
Upon actuation by a user or an electronic control unit such as a unit for auton-omous driving, the brake valve arrangement 10 provides a brake pressure cor-responding to the degree of actuation provided by the user or a respective sig-nal. To allow an actuation, the brake valve arrangement 10 comprises an actua-tion element 14, which is formed as a brake pedal in this embodiment. The brake valve arrangement 10 is configured to modulate the brake pressure sup-plied to the working connection 9 dependent on a degree of actuation of the actuation element 14. If the brake pedal 14 is only slightly actuated, a low brake pressure is supplied to the working connection 9 while a high brake pressure is supplied to the working connection 9 when the brake pedal 14 is fully actuated.
The brake valve arrangement 10 is connected to the front axle brake modula-tor 110 and the rear axle brake modulator 114 via connecting lines 116 and 118, respectively. In this embodiment the brake valve arrangement 10 is formed as a single circuit brake valve arrangement 10 having only one working connection 9 for providing brake pressure. Both, the front axle connecting line 116 connecting the brake valve arrangement 10 to the front axle brake modulator 110 as well as the rear axle connecting line 118 connecting the brake valve arrangement 10 to the rear axle brake modulator 112 are connected to the same working connec-tion 9 of the brake valve arrangement 10.
In other embodiments, the brake valve arrangement 10 also could be formed as a multi circuit brake valve arrangement 10 having multiple working connec-tions 9 for providing the same and/or different brake pressures to the brake cir-cuits 102, 104.
The brake modulators 110, 112 receive the brake pressure provided by the brake valve arrangement 10 and transfer it to the respective brake actua-tors 106.1, 106.2, 108.1, 108.2. Therefore, the brake modulators 110, 112 are also connected to the compressed air supply via supply lines 120.2, 120.3. It shall be noted that the front axle brake modulator 110 and/or the rear axle brake modulator 112 may also be configured to further modify the brake pressure. For example, the front axle brake modulator 110 could comprise Anti-lock Braking System-modules (not shown) for providing an ABS-function. Moreover, the brake actuators 106.1, 106.2, 108.1, 108.2 may also be directly connected to the brake valve arrangement 10.
For releasing the brake of the vehicle 200 the break pressure needs to be re-leased from the brake actuators 106.1, 106.2, 108.1 108.2. The brake valve arrangement 10 is therefore configured to exhaust the brake actuators 106.1, 106.2, 108.1 108.2 by connecting the working connection 9 to the ex-haust portion 12. In order to exhaust pressurized air, the air needs to be re-leased to the environment through an opening. Such an opening, however, al-lows water to enter the brake system 100.
Brake valve arrangements, in particular brake valve arrangements having a brake pedal, or even brake modulators 110 and 112, under certain circum-stances, are usually located in a relatively low position in comparison to chassis of the vehicle 200. A maximum fording depth of the vehicle 200 is thereby lim-ited, since water could ingress in the brake system 100 via e.g., the exhaust portion 12 for the brake valve arrangement 10 and via corresponding exhaust ports of brake modulators 110 and 112 when the vehicle 200 drives through water and the water level reaches to the exhaust portion. It should however be noted that water ingression could be considered as a general problem with any of the brake valves (including brake modulators) in the vehicles with reduced ground clearances such as a bus.
In regular vehicles, the available maximum fording depth is sufficient and standard brake valve arrangements assemblies can be used. If however, in-creased fording depths are needed, special measures need to be taken. There-fore, fording versions of brake valve arrangements and/or brake valve arrange-ment assemblies and/or brake modulators are disclosed in the present invention.
In Fig. 1, the brake valve arrangement 10 has a housing 3 for receiving the electronic components, which is connected to an exhaust port 11. The damping chamber 11 may be provided by an exhaust silencer. For releasing the brakes of the vehicle 200, the brake pressure is released from the brake actua-tors 106.1, 106.2, 108.1 108.2 via the connecting lines 116, 118, the brake valve arrangement 10, the housing 3 for receiving the electronic components, the exhaust line 122, and then via the exhaust port 11.
Fig. 2a shows a pneumatic device 1 being for example an axle modulator 20. As shown in the schematic view according to Fig. 2a, a pneumatic device 1 ac-cording to the invention comprises a pressure-carrying section 15 which is in fluid communication with a primary exhaust path 17 for exhausting pressurized air in an exhaust direction R. The pneumatic device 1 comprises a one-way valve 19 arranged in the primary exhaust path 17. The one-way valve 19 is con-figured to enable exhaust of the pressure-carrying section 15 along the exhaust direction R, for instance, in case the pressure in the pressure-carrying sec-tion 15 exceeds a predetermined exhaust pressure threshold. In this way, ex-haust of the pressure-carrying section 15 via the primary exhaust path 17 and the one-way valve 19 meets the exhaust response time requirements of a brake system 100 of a vehicle 200 (see Fig. 1) .
The one-way valve 19 is configured to allow exhaust of the pressure-carrying section 15 in the exhaust direction R and to prevent ingress of any fluid in the opposite direction. Thus, liquid from the environment cannot pass the one-way valve 19.
The pneumatic device 1 further comprises a secondary exhaust path 21 in fluid communication with the pressure-carrying section 15. The pneumatic device 1 has a sealing device 23 arranged in the secondary exhaust path 21 which is adapted to switch at least between a normal state Z1 and a sealing state Z2. In the normal state Z1 of the sealing device 23, the secondary exhaust path 21 can be flown through in the exhaust direction R in order to exhaust a residual pressure. In general, said residual pressure is below the predetermined exhaust pressure threshold. In the sealing state Z2, the sealing device 23 sealingly blocks the secondary exhaust path 21. Thus, the sealing device 23 is config-ured to prevent flow through the secondary exhaust path 21 in the sealing state Z2.
In order to switch from the normal state Z1 to the sealing state Z2, the sealing device 23 moves from a first position P1 to a second position P2. Preferably, the first position P1 is downstream of the second position P2 in the exhaust di-rection R. It is preferred that the sealing device 23 is adapted to change from the normal state Z1 to the sealing state Z2 in case a liquid in the secondary ex-haust path 21 exceeds a threshold level S.
Fig. 2b shows a second embodiment of the pneumatic device 1. Reference is made to the description of the embodiment shown in Fig. 2a. The embodiment shown in Fig. 2b differs from the embodiment shown in Fig. 2a by a spring 35 advancing the one-way valve 19 towards its closed state Z3. In an opened state Z4 indicated by dotted lines, the primary exhaust path 17 can be flown through in the exhaust direction R.
Fig. 2c shows a third embodiment of the pneumatic device 1. Reference is made to the description of the embodiment shown in Figs. 2a and 2b. The em- bodiment shown in Fig. 2c differs from the embodiment shown in Fig. 2b in that the exhaust direction R and the exhaust direction R extend parallel along a sec-tion of the exhaust direction 19 and secondary exhaust path 21. The one-way valve 19 partly defines the secondary exhaust path 21. The sealing device 23 is arranged in a receiving space 37 of the one-way valve 19. Similar to the expla-nation provided in relation to Fig. 2b, sealing device 23 can be buoyant in water and close secondary exhaust path 21 to prevent water ingression. However, when the water moves sealing device 23 to close secondary exhaust path 21, exhaust direction R is available for the pressurized air to exhaust from pressure-carrying section 15 towards primary exhaust path 17.
The pneumatic device 1 shown in Fig. 3 is an axle modulator 20 which compris-es a lower housing 2 and a relay valve piston 3. The working of axle modulator 20 in accordance with the present embodiment is as follows.
When control pressure is received via control port 3.1, relay valve piston 3 line-arly reciprocates within housing 2. Relay valve piston 3 includes an impact por-tion 3.2 that impinges on a relay valve seat 92 to move relay valve seat 92 against spring 35’s extension force. Until this point, relay valve seat 92 is held in its position by a stopper 99 against spring 35’s extension force.
In any case, as relay valve seat 92 moves downward, connection between an inlet port 94 and a chamber 96 is established. This results in pressurized air exiting via an outlet port 98, which is eventually received in one or more of the actuators 106.1, 106.2, 108.1 and 108.2 for applying the brakes.
However, when air flow via port 98 towards primary exhaust path 17 occurs dur-ing situations such as when a parking brake needs to be activated, such an air flow passes through one-way valve 19 and then to a silencer or damping cham-ber and then to exhaust port 11 before it reaches environment 5. Thus, when air flow via port 98 towards path 17 occurs, a pressure-carrying section 15 may also receive air as it is connected to chamber 96 and/or port 98 and/or environ-ment 5 in this situation.
The one-way valve 19 and the sealing device 23 of Fig. 3 are shown in more detail in Fig. 4 and reference is made to the description below.
The sealing device 23 comprises a sealing body 25 and a sealing seat 27. The sealing body 25 is ball-shaped and preferably adapted to be buoyant on water. The sealing seat 27 is arranged above the sealing body 25 in the shown ar-rangement.
In Fig. 4, the sealing device 23 is shown in the normal state Z1 in which the sealing body 25 rests at a retaining part 28. The retaining part 28 is arranged downstream the sealing body 25 in the exhaust direction R. The ball-shaped sealing body 25 is configured to rest in a sealing manner against the sealing seat 27 in the sealing state Z2 or at an abutment surface 28.1 of the retaining part 28 in other states. The sealing seat 27 is facing downstream in the exhaust direction R (see Fig. 2c) . The sealing body 25 is arranged downstream of the sealing seat 27 in the exhaust direction R.
The retaining part 28 preferably holds the ball-shaped sealing body 25 in a posi-tion close to the sealing seat 27 by means of an abutment surface 28.1.
Under the influence of gravity, sealing body 25 rests on or at abutment sur-face 28.1. When the exhaust air flow occurs in direction R (c. f. Figs. 2a to 2c and Fig. 4) , the pressure of the exhaust air pushes piston 33 in the direction R against the resistance of spring 35. Note that during the exhaust air flow in di-rection R, sealing body 25 is firmly seated on abutment surface 28.1 in its nor-mal state Z1. As piston 33 moves downwards in direction R, sealing member 43 is lifted off valve seat 31 as said valve seat 31 moves in direction R along with piston 33. Understandably, this creates a gap between sealing member 43 and valve seat 31 defining a part of the primary exhaust path 19 through which the exhaust air flows and reaches a silencer 101 (see Fig. 3) , and from there to ex-haust port 11 (see Fig. 1) .
On the other hand, in case water or any other fluid in the secondary exhaust path 21 exceeds a predefined threshold level S (see Fig. 2a-2c) , the sealing body 25 will float on the water and thus be lifted off from abutment surface 28.1 and moved to contact the sealing seat 27 in its sealing state Z2. Thus, the sec-ondary exhaust path 21 is blocked and an undesired water ingress is avoided. It should be noted that, that exhausting air in the direction R is still possible when water lifts sealing body 25 and closes path 21 because, as mentioned above, due to the exhaust pressure, piston 33 is moved in direction R creating gap be-tween valve seat 31 and sealing member 43.
Preferably, the retaining path 28 is attached to the piston 33 by means of a snap connection.
The retaining part 28 has an exhaust channel 29 extending in the exhaust direc-tion R. The exhaust channel 29 partly defines the secondary exhaust path 21. The one-way valve 19 has a receiving space 37 at piston 33. The sealing body 25 and at least a part of the retaining part 28 are received within said re-ceiving space 37. The sealing seat 27 is provided by the one-way valve 19 at an entrance to said receiving space 37 above the sealing body 25. Thus, the sec-ondary exhaust path 21 is partly defined by the one-way valve 19.
The one-way valve 19 in Fig. 4 is shown in the closed state Z3. The one-way valve 19 comprises the piston 33 that is configured to selectively rest against the valve seat 31 in the closed state Z3 of the one-way valve 19. The spring 35 is guided by an annular surface of the piston 33 and rests against a spring seat 36 provided by the piston 33. The piston 33 is movably received in a valve guide 39 comprising the valve seat 31. Thus, when exhaust air flow occurs in direction R, because of which sealing body 25 is firmly rested against abutment surface 28.1, piston 33 linearly moves downwards in direction R oriented in the direction with the help of valve guide 39. Moreover, the residual pressure below a predetermined value to move piston 33 can be exhausted via the secondary exhaust path 21 with the sealing body 25 resting against the abutment sur-face 28.1.
It can be noticed that, Fig. 4 illustrates a damping member 44 having a rub-ber 45 which is arranged between piston 33 and valve guide 39. In accordance with the present illustration in Fig. 4, the purpose of damping member 44 is to dampen any oscillatory movement occurring due to the exhaust air flow (at a relatively high pressure) between piston 33 and valve guide 39. The damping member 44 comprises a first damping ring 44.1 and a second damping ring 44.2 and the piston 33 has a corresponding first groove 46 configured to receive the damping rings 44.1, 44.2.
In accordance with the illustrated embodiment of Fig. 4, one of the technical advantages of using damping member 44 is, by dampening the oscillatory movement during the exhaust, the resulting exhaust noise is reduced.
On the other hand, a sealing member 43 ensures at a state i.e., when piston 33 is not moving an air-tight interface is provided at the junction of sealing mem-ber 43 and valve seat 31. Further, the piston 33 has a second groove 47 con-figured to receive the sealing member 43 formed as a sealing ring. The sealing member 43 preferably has a rubber 48.
LIST OF REFERENCE SIGNS (PART OF THE DESCRIPTION)
1 pneumatic device
2 lower housing
3 relay valve piston
3.1 control port
3.2 impact portion
5 environment
7 supply connection
9 working connection
10 brake valve arrangement
11 exhaust port
12 exhaust portion
14 actuation element
15 pressure-carrying section
17 primary exhaust path
19 one-way valve
20 axle modulator
21 secondary exhaust path
23 sealing device
25 sealing body
27 sealing seat
28 retaining part
28.1 abutment surface
29 exhaust channel
31 valve seat
33 piston
35 spring
36 spring seat
37 receiving space
39 valve guide
41 upper section of piston
43 sealing member
44 damping member
44.1, 44.2 damping ring
45 elastomer, rubber of damping member
46 (first) groove
47 second groove
48 rubber of sealing member
92 relay valve seat
94 inlet port
96 chamber
98 outlet port
99 stopper
100 brake system
101 silencer
102 front axle brake circuit
104 rear axle brake circuit
106.1, 106.2 front axle brake actuators
108.1, 108.2 rear axle brake actuators
110 front axle brake modulator
112 rear axle brake modulator
114 compressed air supply
116 front axle connecting line
118 rear axle connecting line
120.1, 120.2, 102.3 supply lines
122 exhaust line
200 vehicle
204 front axle
206 rear axle
208.1, 208.2 front wheels
210.1, 210.2 rear wheels
F liquid
R exhaust direction
Z1 normal state
Z2 sealing state
Z3 exhaust state
S threshold level
P1 first position
P2 second position

Claims

A pneumatic device (1) for a pneumatic brake system (100) of a vehicle (200) , the pneumatic device (1) comprising:

- a primary exhaust path (17) for exhausting pressurized air along an ex-haust direction (R) ;

- a one-way valve (19) arranged in the primary exhaust path (17) and con-figured to enable exhaust of pressurized air along the exhaust direction (R) in case the pressure exceeds a predetermined exhaust pressure threshold;

- a secondary exhaust path (21) for exhausting a residual pressure from the pressure-carrying section (15) along the exhaust direction (RR) ; and

- a sealing device (23) arranged in the secondary exhaust path (21) and being adapted to switch at least between a normal state (Z1) and a sealing state (Z2) ,

wherein in the normal state (Z1) of the sealing device (23) the secondary exhaust path (21) can be flowed through in the exhaust direction (R) and in the sealing state (Z2) of the sealing device (23) the secondary exhaust path (21) is sealingly blocked at least in a direction opposite the exhaust direction R.
The pneumatic device (1) according to claim 1,

wherein the sealing device (23) is adapted to change from the normal state (Z1) to a sealing state (Z2) in case a level of ingression of a liquid (F) in the secondary exhaust path (21) exceeds a threshold level (S) .
The pneumatic device (1) according to any one of the preceding claims,

wherein the sealing device (23) comprises a sealing body (25) and a sealing seat (27) , wherein the sealing body (25) is configured to rest in a sealing manner against the sealing seat (27) in a sealing state (Z2) .
The pneumatic device (1) according to claim 3,

wherein the sealing body (25) is adapted to be floatable on water.
The pneumatic device (1) according to any one of the claims 3 or 4,

wherein the sealing seat (27) is facing downstream in the exhaust direc-tion (R) , and wherein the sealing body (25) is arranged downstream of the seal-ing seat (27) in the exhaust direction (R) .
The pneumatic device (1) according to any one of the claims 4 to 5,

wherein the sealing body (25) rests at a first position (P1) in the normal state (Z1) and moves to a second position (P2) in the sealing state (Z2) , and

wherein the first position (P1) is downstream of the second position (P2) in the exhaust direction (R) .
The pneumatic device (1) according to any one of the claims 5 or 6,

wherein said sealing device (23) further comprises a retaining part (28) arranged downstream of the sealing body (25) in the exhaust direction (R) , and wherein the sealing body (25) rests at the retaining part (28) in the first position (P1) in the normal state (Z1) .
The pneumatic device (1) according to claim 7,

wherein the retaining part (28) has an exhaust channel (29) extending in the exhaust direction (R) at least partly defining the secondary exhaust path (21) .
The pneumatic device (1) according to any one of the preceding claims,

wherein the one-way valve (19) comprises:

- a valve seat (31) ;

- a movable piston (33) configured to selectively rest against the valve seat (31) in a closed state (Z3) of the one-way valve (19) ; and

- a spring (35) configured to advance the piston (33) towards the valve seat (31) .
The pneumatic device (1) according to claim 9,

wherein the secondary exhaust path (21) is at least partly defined by the one-way valve (19) , in particular the secondary exhaust path (21) extends through the piston (33) .
The pneumatic device (1) according to claim 9 or 10,

wherein the piston (33) has a damping member (44) comprising a rubber (45) und is configured to dampen oscillation of the piston (33) .
The pneumatic device (1) according to any one of the claims 11,

wherein the damping member (44) is attached to the piston (33) by a positive-fit, preferably the damping member (44) comprises one or more damp-ing rings (44.1, 44.2) and the piston (33) has a corresponding groove (46) , con-figured to receive the damping ring (44.1, 44.2) .
The pneumatic device (1) according to any one of the claims 10, 11 or 12,

wherein the piston (33) has a receiving space (37) and the sealing device (23) is arranged in the receiving space (37) .
The pneumatic device (1) according to any one of the claims 10 to 13,

wherein the one-way valve (19) further has a valve guide (39) comprising the valve seat (31) and being configured to at least partly receive the movable piston (33) .
The pneumatic device (1) according to any one of the claims 10 to 14,

wherein the piston (33) has a sealing member (43) configured to sealing-ly rest at least against the valve seat (31) in the closed state (Z3) of the one-way valve (19) , wherein the sealing member (43) comprises a rubber (48) .
The pneumatic device (1) according to any one of the claims 14 or 15,

wherein the sealing member (43) is attached to the piston (33) by a posi-tive-fit.
The pneumatic device (1) according to any one of the claims 13 to 16,

wherein the sealing member (43) is attached to the piston (33) by a posi-tive-fit, in particular the sealing member (43) is formed as one or more sealing rings, wherein the groove (46) is a first groove (46) and the piston (33) has a corresponding second groove (47) configured to receive the sealing member (43) .
The pneumatic device (1) according to any one of the preceding claims,

wherein the sealing device (23) is adapted to sealingly block the second-ary exhaust path (21) in the sealing state (Z2) in a direction opposite the ex-haust direction (R) and to enable flow through the secondary exhaust path (21) in the exhaust direction (R) .
A pneumatic brake system (100) of a vehicle (200) , comprising a pneu-matic device (1) , in particular a brake valve arrangement (10) or an axle modu-lator (20) , according to any one of the preceding claims.