PNEUMATIC VALVE WITH VENTING GUIDE AND TILT PROTECTION

Abstract

A pneumatic valve (1) includes a housing (6), a supply connection (8), a working connection (10) for providing working pressure (pB), an exhaust portion (12) for discharging pressurized air, an attachment portion (74), a valve member (24) and a venting guide (4). The venting guide (4) has a venting channel (108) and complementary connection elements (76) engaging the attachment portion (74), a spout (78), and a support projection (100). The support projection (100) is positioned adjacent to a contact region (102) of the housing (6) and configured to abut the contact region (102) to block tilting of the venting guide (4) relative to the housing (6). A vehicle (300) includes a brake system (200) having the pneumatic valve (1).

Claims

1. A pneumatic valve (1) for providing a working pressure (pB), comprising a housing (6) having a first housing side (44); a supply connection (8) for receiving a supply pressure (pS); a working connection (10) for providing the working pressure (pB); an exhaust portion (12), for discharging pressurized air from the pneumatic valve (1), located proximate to the first housing side (44), an attachment portion (74); a valve member (24) continuously slidable from an exhaust position (28) to a fully open position (30), wherein the working connection (10) is in fluid communication with the exhaust portion (12) when the valve member (24) is in the exhaust position (28), and wherein the working connection (10) is in fluid communication with the supply connection (8) and sealed from the exhaust portion (12) when the valve member (24) is in an at least partially open position, and a venting guide (4), the venting guide (4) comprising a venting channel (108) and complementary connection elements (76) engaging the attachment portion (74) the venting guide (4) comprising a spout (78) and a support projection (100), wherein the support projection (100) is positioned adjacent to a contact region (102) of the housing (6) provided on the first housing side (44) and configured to abut the contact region (102) to block tilting of the venting guide (4) relative to the housing (6).

2. The pneumatic valve (1) according to claim 1, wherein the spout (78) is an essentially L-shaped spout (78) having a first leg (104) and a second leg (106).

3. The pneumatic valve (1) according to claim 2, wherein the support projection (100) extends opposite the first leg (104) of the L-shaped spout (78).

4. The pneumatic valve (1) according to claim 2, wherein the venting guide (4) comprises a venting channel (108) having a first venting channel portion (110) extending in the first leg (104) and a second venting channel portion (112) extending in the second leg (106) of the L-shaped spout (78), wherein a tapered end portion (130) of the first venting channel portion (110) extends beyond an intersection (114) between the first venting channel portion (110) and the second venting channel portion (112).

5. The pneumatic valve (1) according to any of claim 1, wherein the attachment portion (74) and the complementary connection elements (76) allow rotation of the venting guide (4) around a rotational axis (A_R) when engaged with each other.

6. The pneumatic valve (1) according to claim 1, wherein the venting guide (4) engages a corresponding slot (118) to block rotation of the venting guide (4) around the rotational axis (A_R), wherein the slot (118).

7. The pneumatic valve (1) according to claim 6, wherein a protrusion (116) of the venting guide (4) extends from the support projection (100) towards the contact region (102).

8. The pneumatic valve (1) according to claim 7, wherein the protrusion (116) of the venting guide (4) engages the slot (118).

9. The pneumatic valve (1) according to claim 1, wherein a protrusion (116) of the venting guide (4) extends from the support projection (100) towards the contact region (102), wherein the contact region (102) of the housing comprises a first contact surface (132) and a second contact surface (138) transverse to the first contact surface (132), wherein the support projection (100) is positioned adjacent to the first contact surface (132) and configured to abut the first contact surface (132) to block tilting of the venting guide (4) relative to the housing (6) in a first tilt direction (T1), and wherein the protrusion (116) is positioned adjacent to the second contact surface (138) and configured to abut the second contact surface (138) to prevent tilting of the venting guide (4) relative to the housing (6) in a second tilt direction (T2) opposite the first tilt direction (T1).

10. The pneumatic valve (1) according to claim 1, further comprising a guide element (26), wherein the valve member (24) is slidably arranged on the guide element (26), the guide element (26) comprising an internal channel (66), wherein the internal channel (66) forms part of an exhaust flow path (67) between the working connection (10) and the exhaust portion (12) when the valve member (24) is in the exhaust position (12).

11. The pneumatic valve (1) according to claim 10, wherein the venting guide (4) is formed separately from the guide element (26) and wherein the attachment portion (74) is formed on the guide element (26).

12. The pneumatic valve (1) according to claim 11, further comprising a valve sealing member provided at a transition between the internal channel (66) and the venting channel (108) for establishing a sealing connection between the venting guide (4) and the guide element (26).

13. The pneumatic valve (1) according to claim 1, wherein the venting guide (4) is snap fitted to the attachment portion (74).

14. The pneumatic valve (1) according to claim 1, wherein the venting guide (4) comprises one or more reinforcement ribs (122) extending from the support projection (100) towards a main venting guide body (124) of the venting guide (4).

15. The pneumatic valve (1) according to claim 1, wherein a gap (126) is formed between the contact region (102) and the support projection (100) when the venting guide (4) is in a neutral position (128).

16. The pneumatic valve (1) according to claim 1, wherein the contact region (102) forms an end stop for the venting guide (4) limiting excessive loads on the attachment portion (74) when the venting guide (4) is assembled on the attachment portion (74).

17. The pneumatic valve (1) according to claim 6, wherein the slot is formed in the housing (6).

18. The pneumatic valve (1) according to claim 6, wherein the slot is formed in an adapter (120) connected to the housing (6).

19. The pneumatic valve (1) according to claim 18, wherein the adapter (120) is rotationally fixed relative to the housing (6).

20. A vehicle (300) comprising a brake system (200) comprising a pneumatic valve (1) according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the accompanying drawings:

[0030] FIG. 1 is a schematic layout of a vehicle having a pneumatic valve, wherein the pneumatic valves forms a brake valve of a brake system in a fording version of the vehicle;

[0031] FIG. 2 is a cross-section view of the pneumatic valve;

[0032] FIG. 3 is an enlarged detail view of FIG. 2;

[0033] FIG. 4 is a top view of a venting guide of the pneumatic valve of FIG. 2;

[0034] FIG. 5 is a side view of the venting guide of FIG. 4;

[0035] FIG. 6 is a detail view of a pneumatic valve according to a second embodiment;

[0036] FIG. 7 is a detail view of a pneumatic valve according to a third embodiment; and

[0037] FIG. 8 is a detail view of a pneumatic valve according to a fourth embodiment.

DETAILED DESCRIPTION

[0038] A vehicle 300, in particular a commercial vehicle 302, includes a front axle 304 and a rear axle 306. For braking front wheels 308.1, 308.2 of the front axle 304 and rear wheels 310.1, 310.2 of the rear axle 306, the vehicle 300 includes a brake system 200 having a front axle brake circuit 202 for braking the front wheels 308.1, 308.2 and a rear axle brake circuit 204 for braking the rear wheels 310.1, 310.2. For braking the wheels 308.1, 308.2, 310.1, 310.2, the brake system 200 includes front axle brake actuators 206.1, 206.2 and rear axle brake actuators 208.1, 208.2. The front axle brake actuators 206.1, 206.2 are connected to a front axle brake modulator 210 while the rear axle brake actuators 208.1, 208.2 are connected to a rear axle brake modulator 212. For providing compressed air at a supply pressure pS, the brake system 200 includes a compressed air supply 214. Of course, it may comprise more than one air supply.

[0039] In order to brake the vehicle 300 a brake pressure pB needs to be supplied to the front axle brake modulator 210 and the rear axle brake modulator 212. For providing the brake pressure pB, the brake system 200 includes a brake valve 2. In this embodiment, a pneumatic valve 1 forms the brake valve 2. The pneumatic valve 1 includes a housing 6, having a supply connection 8, a working connection 10, and an exhaust portion 12. The supply connection 8 is connected to the compressed air supply 214 via supply line 220.1 for receiving pressurized air at the supply pressure pS.

[0040] In this embodiment the pneumatic valve 1 is configured for manual actuation by a user. However, the pneumatic valve 1 may also be formed as an electronically actuated pneumatic valve 1. Upon actuation by a user the pneumatic valve 1 forming the brake valve 2 provides a brake pressure pB corresponding to the degree of actuation provided by the user. To allow an actuation, the pneumatic valve 1 includes an actuation element 14, which is formed as a brake pedal 16 in this embodiment. The brake valve 2 is configured to modulate the brake pressure pB supplied to the working connection 10 dependent on a degree of actuation of the actuation element 14. If the brake pedal 16 is only slightly actuated, a low brake pressure pB is supplied to the working connection 10 while a high brake pressure pB is supplied to the working connection 10 when the brake pedal 16 is fully actuated.

[0041] The pneumatic valve 1 is connected to the front axle brake modulator 210 and the rear axle brake modulator 214 via connecting lines 216, 218. In this embodiment, the pneumatic valves 1 is formed as a single circuit brake valve 2 having only one working connection 10 for providing brake pressure pB. Both, the front axle connecting line 216 connecting the brake valve 2 to the front axle brake modulator 210 as well as the rear axle connecting line 218 connecting the brake valve 2 to the rear axle brake modulator 212 are connected to the same working connection 10 of the brake valve 2. In other embodiments, the pneumatic valve 1 could also be formed as a multi circuit pneumatic valve 1 having multiple working connections 10 for providing the same and/or different pressures.

[0042] The brake modulators 210, 212 receive the brake pressure pB provided by the brake valve 2 and provide pressurized air at the same brake pressure pB but at a higher volume to the respective brake actuators 206.1, 206.2, 208.1, 208.2. Therefore, the brake modulators 210, 212 are also connected to the compressed air supply via supply lines 220.2, 220.3. It shall be noted that the front axle brake modulator 210 and/or the rear axle brake modulator 212 may also be configured to further modify the brake pressure pB. For example, the front axle brake modulator 210 could comprise ABS-modules (not shown) for providing an ABS-function. Moreover, the brake actuators 206.1, 206.2, 208.1, 208.2 may also be directly connected to the brake valve 1.

[0043] For releasing the brake of the vehicle 300, the break pressure pB needs to be released from the brake actuators 206.1, 206.2, 208.1 208.2. The pneumatic valve 1 is therefore configured to exhaust the brake actuators 206.1, 206.2, 208.1 208.2 by connecting the working connection 10 to the exhaust portion 12. In order to exhaust pressurized air, the air needs to be released to the environment through an opening. Such an opening, however, allows water to enter the brake system 200. Brake valves, in particular brake valves having a brake pedal, are usually located in a low position of the vehicle 300. A maximum fording depth of the vehicle 300 is thereby limited, because water could ingress in the brake system 200 via the exhaust portion 12 when the vehicle 300 drives through water and the water level reaches to the exhaust portion. In regular vehicles, the available maximum fording depth is sufficient and pneumatic valves 1 of a standard type may be used as the brake valve 2. If however, when increased fording depths are needed, special measures need to be taken. Therefore, fording versions of pneumatic valves 1, in particular pneumatic brake valves 2, are provided.

[0044] In FIG. 1, the brake valve 2 is a fording version, because the pneumatic valve 1 forming the brake valve 2 includes a venting guide 4. The venting guide 4 is connected to an exhaust line 222, which is connected to a remote exhaust silencer 224. For releasing the brakes of the vehicle 300, the brake pressure pB is released from the brake actuators 206.1, 206.2, 208.1 208.2 via the connecting lines 216, 218, the brake valve 2, and its venting guide 4, the exhaust line 222, and the remote exhaust silencer 224.

[0045] The venting guide 4 is sealingly connected to an attachment portion 74 of the pneumatic valve 1 and thereby enables a sealing connection between the pneumatic valve 1 and the exhaust line 222. The remote exhaust silencer 224 is spaced apart from the brake valve 1 and placed at a high position on the vehicle 300. By placing the exhaust silencer 224 at a high position of the vehicle 300, ingress of water into the brake system 200 is prevented when the vehicle 300 drives through water. Providing the exhaust silencer 224 remote of the pneumatic valve 1 may be desirable for noise protection in other applications. For example, passengers may be protected from excessive noise by placing the exhaust silencer 224 at a location remote from a passenger cabin, when the commercial vehicle 302 is a bus.

[0046] FIG. 2 shows the pneumatic valve 1 forming the brake valve 2 depicted in FIG. 1 in more detail. The housing 6 defines a first valve cavity 18 and a second valve cavity 20. A piston 22 of the actuation element 14 is slidably arranged in the first valve cavity 18. A valve member 24 and a guide element 26 are arranged in the second valve cavity 20. The valve member 24 is slidably arranged on the guide element 26 such that it is movable between an exhaust position 28 shown in FIG. 2 and a fully open position 30. In the exhaust position 28 a first valve member side 34 of a valve member head 32 of the valve member 24 abuts a first valve seat 35 arranged on a transition 36 between the first valve cavity 18 and the second valve cavity 20. As will be explained in more detail below, movement of valve member 24 is possible due to contact between a piston head 60 and valve member head 32. In the fully open position 30 the piston 22 abuts a hard stop 62 formed by the housing on the transition 36 between the first valve cavity 18 and the second valve cavity 20. The hard stop 62 limits the pistons 22 range of movement such that the valve member 24 reaches the fully open position 30 when the piston 22 contacts the hard stop 62. In the fully open position 30, a second valve member side 38 of the valve member head 32 and the guide element 26 are preferably spaced apart to prevent damages on the valve member 24. A distance between valve member 24 and valve seat 35 reaches its maximum, when the piston 22 reaches the fully open position 30 (i.e. abuts the hard stop 62). Since the stop function is already provided by the hard stop 62, no physical contact is required between the second valve member side 38 and the guide element 26. Thus, the valve member 24 is prevented from damages. The valve member 24 is biased into the exhaust position 28 by a return spring 40 arranged between the second valve member side 34 and a bottom section 42 of the guide element 26.

[0047] The guide element 26 is inserted into the second valve cavity 20 from a first housing side 44 and held in place by a lock ring 46. For leak prevention between an outer circumferential face 48 of the guide element 26 and an inner wall 50 of the housing 6 defining the second valve cavity 20, an O-ring 52 is provided between the guide element 26 and the inner wall 50.

[0048] The piston 22 is inserted into the first valve cavity 18 from a second housing side 54. Another O-ring 52 is provided between the piston 22 and a second inner wall 56 of the housing 6 defining the first valve cavity 18. The piston 22 sealingly closes off the first valve cavity 18 and is movable between a released position 58 shown in FIG. 2 and a fully actuated position. In the fully actuated position the piston head 60 of the piston 22 abuts the valve member head 32 on the first valve member side 34 and the piston 22 abuts the hard stop 62 formed by the housing on the transition 36 between the first valve cavity 18 and the second valve cavity 20.

[0049] The piston 22 is biased towards the released position 58 (in FIG. 2 upwards) by a piston spring 64 such that the piston 22 remains in the released position 58 as long as no force larger than a corresponding force provided by the piston spring 64 is provided to the brake pedal 16. A pressure piece 21, a set spring 23, and a spring seat 25 functionally connect the brake pedal 16 to the piston 22. A push rod 27 of the brake pedal 16 is received in the pressure piece 21, which is in turn slidably received in a cover 29 closing the housing 6 on the second housing side 54. The spring seat 25 is received in a transfer cavity 31 of the piston 22. A connector 33 is screwed on a threaded portion 37 of the pressure piece 21 and extends through the spring seat 25. The cover 29 is fixed to the housing 6 and limits movement of the pressure piece 21 away from the piston 22 (in FIG. 2 upwards). The set spring 23 is arranged between the pressure piece 21 and the spring seat 25 and around the connector 33 for biasing the spring seat 25 away from the pressure piece 21. The connector 33 is slidably received in the spring seat 25. However, a screw head of a screw 39 limits movement of the pressure piece 21 together with connector 33 away from the spring seat 25 such that a maximum distance between the pressure piece 21 and the spring seat 25 is reached when the screw head of the screw 39 abuts the spring seat 25. The set spring 23 between pressure piece 21 and spring seat 25 creates the pneumatic characteristic of the pneumatic valve 1. A maximum stroke of set spring 23 is reached when the pressure piece 21 touches the piston 22. During assembly spring seat 25, pressure piece 21, set spring 23, and connector 33 are assembled together, wherein the screw 39 connects spring seat 25 to connector 33. This preassembly is then assembled in piston 22. Moreover, the piston spring 64 pushes the piston 22 and the spring seat 25 towards the second housing side 54 (upwards in FIG. 2). The screw 39 sets dependent on its position a 0 position between spring seat 25 and connector 33 attached to pressure piece 21. When the screw 39 is loosened, a space between the pressure piece 21 and the spring seat 25 is increased such that the pre-tension of the set spring 23 is decreased.

[0050] Upon actuation of the brake pedal 16, the pressure piece 21 moves towards the first housing side 44 (in FIG. 2 downwards). This movement compresses the set spring 23 and the pressure piece 21 moves towards the spring seat 25. The set spring 23 provides a compression counter force to the spring seat 25 and the piston 22, which in turn moves the piston 22 downwards against the piston spring 64 arranged between the piston 22 and the housing 6. Hence, actuation of the brake pedal 16 leads to compression of the piston spring 64 as well as the set spring 23. An extent by which the pressure piece 21 and the piston 22 move, depends on the compression counter forces (or biasing forces) provided by the set spring 23 and the piston spring 64, since the forces provided by the set spring 23 and the piston spring 64 need to be in equilibrium as long as the pressure piece 21 is spaced apart from the piston 22. Once the set spring 23 has been compressed such that the pressure piece 21 abuts the piston 22, the pressure piece 21 and the piston 22 move in unison. Further actuation of the brake pedal 16 moves the piston 22 towards the fully open position 30 (in FIG. 2 downwards), because a direct connection is established between the brake pedal 16 and the piston 22 via the push rod 27 and the pressure piece 21.

[0051] The set spring 23, the spring seat 25, and the screw 39 provide a mechanism for setting a pedal feedback of the brake pedal 16. When the set spring 23 is pre-tensioned to a high degree, the piston 22 is moved at a light actuation of the brake pedal 16, because large forces are required for further compressing the set spring 23. When, on the other hand, pre-tensioning of the set spring 23 is low, the pressure piece 21 performs a free stroke (or empty stroke) towards the piston 22 upon initial actuation of the brake pedal 16, since almost no force is required for compressing the set spring 23. In this case, when the brake pedal 16 is initially moved, only the pressure piece 21 moves towards the piston 22 while the piston 22 itself substantially maintains its position. The valve member 24 substantially maintains its position as well and consequently no brake pressure pB is provided to the working connection 10.

[0052] After a potential free stroke of the pressure piece 21, the piston 22 is moved from the released position 58 towards the fully open position (in FIG. 2 down-wards) against the biasing force provided by the piston spring 64. In between the released position 58 and the fully open position, the piston head 60 abuts the valve member 24 whereby a sealing contact is formed between the piston head 60 and the valve member head 32. When the piston 22 is further actuated by the brake pedal 16, it pushes the valve member 24 from the exhaust position 28 towards the fully open position 30. The piston 22 is biased towards the released position 58 by the piston spring 64 arranged between the piston 22 and the housing 6 such that the piston 22 returns to the released position 58 when no actuation force is applied to the brake pedal 16.

[0053] The guide element 26 includes an internal channel 66 and a through hole 68 is provided in the valve member head 32 such that the first inner cavity 18 is in fluid communication with the exhaust portion 12 of the brake valve 1, when the piston head 60 is separated from the valve member head 32 (when the piston 22 is in the released position 58). When the actuation element 14 is at least partly actuated, the piston head 60 sealingly contacts the valve member head 32 and thereby separates the exhaust portion 12 from the first valve cavity 18. However, the valve member 24 is then in an at least partially open position wherein the valve member head 32 is separated from the valve seat 35 such that the second valve cavity 20 is in fluid communication with the first valve cavity 18.

[0054] The supply connection 8 is in direct fluid communication with the second valve cavity 20 such that pressurized air at the supply pressure pS is provided thereto. When the valve member 24 is in the exhaust position 28 the second valve cavity 20 is closed off from the first valve cavity 18 and the exhaust so that the supply connection 8 is not directly connected to the exhaust. When a brake pressure shall be applied to the working connection 10 while the valve member 24 is in the exhaust position 28, the brake pedal 16 needs to be actuated (pushed downwards with respect to FIG. 2). The piston 22 then moves against the biasing force of the piston spring 64 and abuts the valve member head 32 with its piston head 60. The valve member head 32 is moved out of the exhaust position and a free space is formed between the valve seat 35 and the first valve member side 34 of the valve member head 32. Pressurized air provided to the second valve cavity 20 via the supply connection 8 may then flow from the second valve cavity 20 to the first valve cavity 18. The working connection 10 is in direct fluid communication with the first valve cavity 18 such that pressurized air at the brake pressure pB is supplied to the working connection 10 when the valve member 24 is an at least partially open position. The pressure level of the brake pressure pB depends on the size of the free space formed between the valve seat 35 and the valve member head 32. If the free space is small, a high pressure drop occurs and the brake pressure pB supplied to the working connection 10 is much smaller than the supply pressure pS. When the valve member 24 is in the fully open position 30, a large free space is formed between the valve seat 35 and the valve member head 32 such that the brake pressure pB is substantially equal to the supply pressure pS. In this case, the brake actuators 206.1, 206.2, 208.1, 208.2 connected to the working connection 10 are fully actuated and a maximum braking force is applied.

[0055] It shall be noted, that movement of the piston 22 depends on actuation of brake pedal 16 and deflection of set spring 23 as well as additional factors like friction and a force supplied by return spring 64. The set spring 23 deflects, since the brake pressure pB established in the first valve cavity 18 acts on the exposed area of the piston 22 facing towards the first valve cavity 18. As the free space between the valve member head 32 and the valve seat 35 increases, the brake pressure pB also increases. The set spring 23 is deflected (compressed) such that part of a movement of the pressure piece 21 towards the first housing side 44 is compensated by set spring 23. Movement of the piston 22 is therefore not necessarily uniform to a movement of push rod 27 and pressure piece 21. A partial braking characteristic of the brake valve 1 is configurable via set spring 23. When the set spring 23 is fully compressed, the pressure piece 21 contacts piston 22 and a uniform movement of piston 22 and push rod 27 is established. Preferably, contact of piston 22 and pressure piece 21 results in a sudden increase of the free space between the valve seat 35 and valve member head 32 resulting in a jump of the pressure level of the brake pressure pB supplied to the first valve cavity 18 and working connection 10. Further preferred, a pressure level of brake pressure pB substantially equal to the supply pressure pS is established when the pressure piece 21 abuts piston 22.

[0056] When the brake pedal 16 is released, the piston 22 and the valve member 24 are returned to the released position 58 and the exhaust position 28 respectively by the springs 40, 64. The valve member head 32 abuts the valve seat 35 and separates the first valve cavity 18 from the second valve cavity 20. Once the valve member 24 has reached the exhaust position 28, further movement of valve member 24 is stopped by the valve seat 35. The piston 22, however, moves on such that the piston head 60 separates from the valve member head 32. The first valve cavity 18 is then once again in fluid communication with the exhaust portion 12 via the through hole 68 and the internal channel 66. Pressurized air at the brake pressure pB may then flow along an exhaust flow path 67 from the working connection 10 to the exhaust portion 12 via the first valve cavity 18, the free space formed between the piston head 60 and the valve member head 32, the through hole 68 and the internal channel 66 formed in the guide element 26.

[0057] The exhaust portion 12 is configured for exhausting air from the pneumatic valve 1. While regular pneumatic valves directly exhaust the air to the environment via an exhaust silencer connected to the exhaust portion 12, the exhaust portion 12 of the pneumatic valve 1 shown in FIG. 2 does not directly exhaust the pressurized air to the environment. Instead, the pressurized air is provided to the venting guide 4. The exhaust portion 12 and the venting guide 4 are further described with relation to FIG. 3 showing a detail of the pneumatic valve 1 depicted in FIG. 2.

[0058] The exhaust portion 12 includes an exhaust cavity 70 formed by the housing 6. The exhaust cavity 70 is arranged between the second valve cavity 20 and an outer opening 72 of the housing 6. The internal channel 66 opens into the exhaust cavity 70. If the venting guide 4 were not part of the pneumatic valve 1, the outer opening 72 would form an opening of the pneumatic valve 1 to the environment. However, as shown in FIG. 3, the venting guide 4 is connected to the guide element 26 of the pneumatic valve 1. An attachment portion 74 having connection elements 75 is provided on the guide element 26 at an end portion of the internal channel 66. In this embodiment, the connection elements 75 are formed as circumferential saw tooth shaped ridges, which are engaged by complementary connection elements 76 of the venting guide 4 formed as snap hooks 77.

[0059] The pneumatic valve 1 includes a valve sealing surface 83, which is formed on the guide element 26 in the depicted embodiment. In particular, the valve sealing surface 83 is an inner sealing face 84 formed on the internal channel 66. To ensure the sealing connection between the venting guide 4 and the attachment portion 74, a sealing element in the form of an O-ring 52 is arranged between the venting guide 4 and the sealing surface 83. In this embodiment, the first sealing face 85 is formed by a step 87 of the internal channel 66. When the complementary connection elements 76 engage the connection elements 75 of the attachment portion 74, the venting guide 4 presses the O-ring 52 against the step 87 and thereby ensures a sealing connection of the venting guide 4 to the guide element 26.

[0060] The venting guide 4 comprises a spout 78 and a support projection 100. It partially extends out of the exhaust cavity 70 and away from the pneumatic valve 1. The spout 78 is L-shaped. A first leg 104 of the spout 78 is adapted to be inserted in a hose (not shown) which can be clamped onto the spout 78 with a hose clamp (not shown). A spout end 93 on the first leg 104 comprises a circumferential ridge 94 preventing a hose clamp from sliding of the spout 78. A first leg length L1 of the first leg 104 is greater than a corresponding second leg length L2 of the second leg 106.

[0061] For guiding the pressurized air received from the exhaust portion 12 of the pneumatic valve 1, the venting guide 4 includes a venting channel 108. A first venting channel portion 110 of the venting channel 108 extends in the first leg 104 while a second venting channel portion 112 intersecting the first venting channel portion 110 at an intersection 114 extends in the second leg 106 of the L-shaped spout 78. In the shown embodiment and preferably the L-shape is bent in a single plane. A central axis of the first venting channel portion 110 and a central axis of the second venting channel portion 112 lie in a common plane.

[0062] In the embodiment shown in FIG. 3, the first venting channel portion 110 intersects the second venting channel portion 112 at a 90? leg angle ? such that the venting channel portions 110, 112 of the venting channel 108 extend perpendicular to each other from the intersection 114. The venting channel portions 110, 112 are formed as cylindrical bores in the spout 78. One or both venting channel portions 110, 112 may also have a non-cylindrical shape. For example the first venting channel portion 110 and/or the second venting channel portion 112 may have a rectangular, octagonal, and/or oval cross-section.

[0063] A tapered end portion 130 of the first venting channel portion 110 extends beyond the intersection 114. In this embodiment, only the tapered end portion 130 extends beyond intersection 114. However, part of the first venting channel portion 110 may preferably extend beyond the intersection 114 as well. The tapered end portion 130 has a conical shape, in particular a circle cone shape. An opening angle ? of the tapered end portion 130 has a value of 120?. The tapered end portion 130 is preferably formed by the tip of a drill bit, when the first venting channel portion 110 is drilled during manufacturing of the venting guide 4. Manufacturing of the venting channel 108 is facilitated since no flat-bottomed hole needs to be provided for forming the first venting channel portion 110.

[0064] Moreover, the tapered end portion 130 improves stability of the pneumatic valve 1. During operation, pressurized air is discharged from the pneumatic valve 1 via the venting channel 108 of the venting guide 4. Air flows from the internal channel 66 of the guide element 26 to the second venting channel portion 112. At the intersection 114, the air flow is redirected into the first venting channel portion 110 and towards the spout end 93. A momentum of the airflow changes and the air exerts forces on the venting guide 4 at the intersection 114. Moreover, a pressure drop occurs between the environment and the pneumatic valve 1 such that a pressure level in the venting channel 108 differs from a pressure level of the environment. This pressure differential also exerts forces on the venting guide 4. The tapered end portion 130 evenly distributes the forces resulting from the pressure differential and from the momentum change of the airflow, such that non-symmetrical loads on the venting guide 4 are substantially limited. Thereby less stress is put on the complementary connection elements 76 of the venting guide 4 as well as the attachment portion 4.

[0065] FIG. 3 depicts the venting guide 4 in a neutral position 128. The first leg 104 of the L-shaped spout 78 laterally extends from the housing 6. No external loads are provided on the spout 78 in the neutral position 128. However, during assembly and or operation, loads are provided on the venting guide 4, in particular on the spout 78. During assembly, the venting guide 4 is pushed onto the guide element 26 such that the complementary connection elements 76 engage the attachment portion 4. For engaging the connection elements 75 of the attachment portion 4, the snap hooks 77 are pushed over the ridges of the attachment portion 4 (upwards with respect to FIG. 3). While being pushed over the ridges of the attachment portion 4, the snap hooks 77 are laterally deformed (horizontally with respect to FIG. 3). For pushing the venting guide 4 onto the attachment portion 74, a first assembly force F_A1 is provided onto the venting guide 4. The first assembly force F_A1 required for pushing the complementary connection elements 76 onto the attachment portion 74 is further increased by an annular spring 80, biasing the snap hooks 77 inwards. A person assembling the pneumatic valve 1 or an assembly apparatus may provide the first assembly force F_A1 unevenly to the venting guide 4, such that the venting guide 4 tilts relative to the guide element 26 (e.g. counter-clockwise with respect to FIG. 3). Moreover, a hose or pipe (not shown in FIG. 3) is pushed over the spout end 93 of spout 78 when the pneumatic valve 1 is installed in the vehicle 300. This exerts a second assembly force F_A2 on the spout 78. Due to the L-shape of the spout 78, a tilting momentum results from the second assembly force F_A2. Moreover, during operation the hose or pipe may exert additional forces on the first leg 104 of the spout 78. An exemplary operational force F_O is illustrated in FIG. 3.

[0066] If those forces F_A1, F_A2, F_0 were not compensated as explained below, the venting guide 4 would excessively tilt relative to the attachment portion 74 which could lead to damages on the complementary connection elements 76 and/or the connection elements 75. Moreover, a sealing connection between the venting guide 4 and the guide element 26 would not be ensured.

[0067] To prevent tilting of the venting guide 4 relative to the housing 6, the venting guide 4 comprises a support projection 100. The support projection 100 extends opposite the first leg 104 from a main venting guide body 124 of the venting guide 4. The second leg 106 and the complementary connection elements 76 are located between the first leg 104 and the support projection 100 in a first direction D1. A central axis of the support projection 100 is substantially parallel to a central axis of the first leg 104, which is particularly conceivable from FIG. 4. In this embodiment, the support projection 100 and the first leg 104 of the spout 4 have a common central axis A_C. In the top view of FIG. 4, the venting guide 4 is symmetrical with respect to this central axis A_C. The top view furthers shows, that the venting guide 4 comprises a total of ten snap hooks 77. However, the venting guide may also comprise less than ten snap hooks 77, preferably two, three, four, five, six, seven, eight, or nine, or more than ten snap hooks 77, preferably eleven, twelve, thirteen, fourteen or fifteen.

[0068] In the embodiment shown in FIG. 3, the support projection 100 has the shape of a shark fin. The shark fin shape facilitates assembly, since no sharp edges are projecting towards a person pushing the venting guide 4 onto the guide element 26. The support projection 100 may also have any other shape. Preferably, the support projection 100 may have a rectangular cross-section in a side view (as shown in FIG. 3). The support projection 100 is positioned adjacent to a contact region 102 of the housing 6. The contact region 102 is preferably formed on the housing 6. However, the contact region 102 may also be formed on other elements of the pneumatic valve 1, for example on an adapter 120 described later with respect to FIG. 7. The contact region 102 is provided on the housing 6 on the first housing side 44. Since, the exhaust cavity 70 opens towards the first housing side 44, the contact region 102 is adjacent to the exhaust cavity 70. In this embodiment, a flat first contact surface 132 of the housing 6 forms the contact region 102. A corresponding flat support surface 134 is arranged opposite the first contact surface 132 on the support projection 100.

[0069] A gap 126 is formed between the first contact surface 132 of the contact region 102 and the support surface 134 of the support projection 100 when the venting guide 4 is in the neutral position 128. The gap 126 reduces overall cost of the pneumatic valve 1, since the venting guide 4 and the housing 6 can be machined with less precision. A gap width 136 of the gap 126 is small. If the venting guide 4 is tilted during assembly and/or operation due to forces F_A1, F_A2, F_O, the venting guide 4 slightly tilts with respect to the housing 6. The gap 126 is thereby closed (the gap width 136 reduced to zero respectively), such that the support projection 100 abuts the contact region 102. The support surface 134 of the support projection 100 then contacts the first contact surface 132 of the contact region 102. Tilting forces provided on the venting guide 4 are transferred to the housing 6 such that excessive tilting of the venting guide 4 relative to the housing 6 is prevented. It shall be understood, that the support projection 100 allows a slight tilt of the venting guide 4 relative to the housing 6 in the shown embodiment. However, the gap width 136 may be chosen such that the relative tilt of the venting guide 4 relative to the housing 6 does not inhibit a sealing connection and that neither the complementary connection elements 76 nor the connection elements 75 are damaged. In other embodiments, the support projection 100 may abut the contact region 102 in the neutral position 128.

[0070] The venting guide 4 further comprises reinforcement ribs 122 shown in FIG. 4. The reinforcement ribs 122 extend from the support projection 100 at a rib angle ? of 20?. The ribs 122 prevent buckling and/or bending of the support projection 100. The rib angel ? is measured in a plane perpendicular to the second venting channel portion 112. In a symmetry plane of the venting channel 108 (the plane shown in FIG. 5), the ribs 122 are inclined at a secondary rib angle ? of about 10?. The ribs 122 support the support projection 100. The support projection 100 may therefore be formed as a thin rib and less material is required for manufacturing the support projection 100. Preferably, the venting guide 4 is made from a plastic material, particularly preferred by injection molding. A preferred material of the venting guide 4 is Polyamid 6 (PA6 or Polycaprolactam). The support projection 100 and the ribs 122 are relatively thin, so that imperfections resulting from different solidifications rates during molding are prevented.

[0071] The ribs 122 are particularly helpful to prevent bending and or buckling of the support projection 100 if the venting guide 4 comprises an anti-rotation feature as shown in the alternative embodiment depicted in FIG. 7 showing only part of the housing 6. The support projection 100 further comprises a protrusion 116 extending towards the contact region 102. The support surface 134 of the support projection 100 is formed on the protrusion 116. However, the support surface 134 may also be formed separate from the protrusion 116. The protrusion 116 engages a slot 118 such that rotation of the venting guide 4 relative to the housing 6 of the pneumatic valve 1 around a rotational axis A_R is substantially limited or prevented. A rotation force provided to the venting guide 4 is transferred to the housing 6 via the protrusion 116. The ribs 122 help transferring such a rotational load. However, it shall be noted that a venting guide 4 comprising an anti-rotation feature may also be formed without ribs 122. In the embodiment shown in FIG. 6, the slot 118 receiving the protrusion 116 is formed in the housing 6. The rotational axis A_R preferably extends centrally through the complementary connection elements 76 and/or the second venting channel portion 112. Together the protrusion 116 and the slot 118 prevent rotation of the venting guide 4. The slot may be easily machined into the housing 6 of the pneumatic valve 1. This provides a simple way to ensure a specific orientation of the first leg 104 of the spout 78 relative to the housing 6.

[0072] However, providing the slot 118 in the housing 6 may not be practical in all cases. Preferably, the slot 118 may therefore be formed in an adapter 120 as shown in FIG. 7. The adapter 120 is rotationally fixed to the housing 6. For example, the adapter 120 may be glued and or screwed to the housing 6. In the alternative embodiment shown in FIG. 6, the support projection 100 engages the slot 118 such that no protrusion 116 is required or the support projection 100 in itself forms the protrusion 116 respectively. Preferably, also embodiments of the pneumatic valve 1 having an adapter 120 may include a protrusion 116 of the venting guide 4 extending form the support projection 100 into slot 118. The adapter 120 may be formed from a plastic material. The functionality of the embodiments shown in FIGS. 6 and 7 with regard to the anti-rotation feature are substantially the same. Rotational loads provided on the venting guide 4 are transferred to the housing 6 via the slot 118 such that the slot 118 inhibits rotation of the venting guide 4 around rotational axis A_R. The adapter 120 may be provided for different orientations of the first leg 104 of the spout 78 with respect to the housing 6. Through this, the pneumatic valve 1 may be easily adapted to different vehicles or use cases.

[0073] FIG. 8 shows a detail of another embodiment of the pneumatic valve 1. In this embodiment, the protrusion 116 does not engage a slot 118. Instead, the protrusion 116 extends inside the exhaust cavity 70 formed by the housing 6. The support projection 100 is positioned adjacent to a second contact surface 138 of the contact region 102 that is perpendicular to the first contact surface 132. In the shown embodiment, the second contact surface 138 is an inner circumferential surface of the housing 6. Similar to the previously discussed embodiments, the support surface 134 of the support projection 100 is again positioned adjacent to the first contact surface 132 of the contact region 102. To prevent tilting of the venting guide 4 in a first tilt direction T1, which is a counter-clockwise direction in FIG. 8, the support surface 134 of the support projection 100 may abut the first contact surface 132 of the contact region 102. To prevent tilting of the venting guide 4 relative to the housing 6 in a second tilt direction T2, which is a clockwise direction in FIG. 8, the protrusion 116 may abut the second contact surface 138. Together, the support projection 100 and the protrusion 116 thus prevent clockwise as well as counter-clockwise rotation of the venting guide 4 relative to the housing 6.

LIST OF REFERENCE SIGNS (PART OF THE DESCRIPTION)

[0074] 1 pneumatic valve [0075] 2 brake valve [0076] 6 housing [0077] 8 supply connection [0078] 10 working connection [0079] 12 exhaust portion [0080] 14 actuation element [0081] 16 brake pedal [0082] 18 first valve cavity [0083] 20 second valve cavity [0084] 21 pressure piece [0085] 22 piston [0086] 23 set spring [0087] 24 valve member [0088] 25 spring seat [0089] 26 guide element [0090] 27 push rod [0091] 28 exhaust position [0092] 29 cover [0093] 30 fully open position [0094] 32 valve member head [0095] 33 connector [0096] 34 first valve member side [0097] 35 valve seat [0098] 36 transition [0099] 37 threaded portion [0100] 38 second valve member side [0101] 39 screw [0102] 40 return spring [0103] 42 bottom section [0104] 44 first housing side [0105] 46 lock ring [0106] 48 outer circumferential face [0107] 50 inner wall [0108] 52 O-ring [0109] 54 second housing side [0110] 56 second inner wall [0111] 58 released position [0112] 60 piston head [0113] 62 hard stop [0114] 64 piston spring [0115] 66 internal channel [0116] 67 exhaust flow path [0117] 68 through hole [0118] 70 exhaust cavity [0119] 74 attachment portion [0120] 75 connection elements [0121] 76 complementary connection elements [0122] 77 snap hooks [0123] 78 spout [0124] 80 annular spring [0125] 83 valve sealing surface [0126] 84 inner sealing face [0127] 87 step [0128] 93 spout end [0129] 94 ridge [0130] 100 support projection [0131] 102 contact region [0132] 104 first leg [0133] 106 second leg [0134] 108 venting channel [0135] 110 first venting channel portion [0136] 112 second venting channel portion [0137] 114 intersection [0138] 116 protrusion [0139] 118 slot [0140] 120 adapter [0141] 122 reinforcement ribs [0142] 124 main venting guide body [0143] 126 gap [0144] 128 neutral position [0145] 130 tapered end portion [0146] 132 first contact surface [0147] 134 support surface [0148] 136 gap width [0149] 138 second contact surface [0150] 200 brake system [0151] 202 front axle brake circuit [0152] 204 rear axle brake circuit [0153] 206.1, 206.2 front axle brake actuators [0154] 208.1, 208.2 rear axle brake actuators [0155] 210 front axle brake modulator [0156] 212 rear axle brake modulator [0157] 214 compressed air supply [0158] 216 front axle connecting line [0159] 218 rear axle connecting line [0160] 220.1, 220.2, supply lines [0161] 202.3 [0162] 222 exhaust line [0163] 224 remote exhaust silencer [0164] 300 vehicle [0165] 302 commercial vehicle [0166] 304 front axle [0167] 306 rear axle [0168] 308.1, 308.2 front wheels [0169] 310.1, 310.2 rear wheels [0170] A_C central axis [0171] A_R rotational Axis [0172] D1 first direction [0173] F_A1 first assembly force [0174] F_A2 second assembly force [0175] F_O operational force [0176] L1 first leg length [0177] L2 second leg length [0178] pB working pressure; brake pressure [0179] pS supply pressure [0180] T1 first tilt direction [0181] T2 second tilt direction [0182] ? leg angle [0183] ? rib angle [0184] ? secondary rib angle [0185] ? opening angle