SEALING APPARATUS FOR AN AIR SUSPENSION DEVICE, AIR SUSPENSION DEVICE, AND METHOD FOR SEALING A PRIMARY VOLUME IN AN AIR SUSPENSION DEVICE

Abstract

A sealing apparatus for an air spring device for sealing a primary volume of the air spring device in particular a working volume of the air spring device, with respect to a secondary volume, including a main body, and a sealing element configured on the circumference of the main body, the sealing element configured such that, in a state in which it is mounted in the air spring device, the sealing element is transferred from a sealed position, in which the sealing element seals the primary volume with respect to the secondary volume, into a released position, in which air passes the sealing element, when a pressure difference between the primary volume and the secondary volume, which pressure difference is set with respect to the secondary volume as a negative pressure in the primary volume, exceeds a threshold value.

Claims

1.-15. (canceled)

16. An air spring device for commercial vehicles, comprising: an air bellows element; a piston element; a primary volume positioned between the air bellows element and the piston element; and a sealing apparatus configured to seal the primary volume of the air spring device with respect to a secondary volume, the sealing apparatus including a main body and a movable sealing element positioned on the circumference of the main body; wherein the sealing element is configured such that, in the mounted state the sealing element is movable from a sealed position where the sealing element seals the primary volume with respect to the secondary volume, to a released position where air passes the sealing element, when a pressure difference between the primary volume and the secondary volume exceeds a threshold value, wherein the pressure difference is set with respect to the secondary volume as a negative pressure in the primary volume, the air spring device having a connecting duct or the exchange of air between the primary volume and the secondary volume, the sealing apparatus being arranged in the connecting duct; and wherein a ratio between an outermost diameter of the main body to an outermost diameter of the sealing element is between 0.78 and 0.98.

17. The air spring device as claimed in claim 16, wherein the secondary volume includes an additional volume.

18. The air spring device as claimed in claim 16, wherein the sealing apparatus is configured as one piece.

19. The air spring device as claimed in claim 16, wherein the sealing element and/or the main body comprises a rubber and/or plastic.

20. The air spring device as claimed in claim 16, wherein the sealing element includes a sealing lip.

21. The air spring device as claimed in claim 20, wherein the sealing lip is flexible.

22. The air spring device as claimed in claim 16, wherein the main body is configured as a ring or as a cylinder.

23. The air spring device as claimed in claim 16, wherein the sealing apparatus is integrated into a stop element, or the main body forming at least one part of the stop element.

24. The air spring device as claimed in claim 20, wherein an angle measured in a non-mounted state between a face of the main body, on which the sealing lip is arranged and the sealing lip is between 30 and 80.

25. The air spring device as claimed in claim 24, wherein the angle is between 35 and 55.

26. The air spring device as claimed in claim 25, wherein the angle is between 42 and 48.

27. The air spring device as claimed in claim 16, wherein the ratio is between 0.91 and 0.97.

28. The air spring device as claimed in claim 27, wherein the ratio is between 0.87 and 0.96.

29. The air spring device as claimed in claim 16, wherein the sealing element projects with respect to the main body as viewed in the axial direction.

30. The air spring device as claimed in claim 16, wherein the sealing apparatus is arranged on or above the piston element as viewed in the axial direction on or above an upper side of the piston element, wherein the upper side faces the primary volume and adjoins the connecting duct.

31. The air spring device as claimed in claim 30, wherein the piston element includes cutouts configured to exchange ambient air, wherein the cutouts adjoin the sealing apparatus.

32. The air spring device as claimed in claim 16, wherein the sealing element bears against an inner side of the connecting duct or a side wall on the upper side of the piston element in the sealed position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further advantages and features result from the following description of preferred embodiments of the subject matter according to the invention with reference to the appended figures. Individual features of the individual embodiments can be combined with one another here within the scope of the invention.

[0027] In the figures:

[0028] FIGS. 1a and 1b show an air spring system in accordance with one preferred embodiment of the present invention;

[0029] FIGS. 2a and 2b show an air spring device and a link of the air spring system from FIG. 1a in plan views; and

[0030] FIGS. 3a and 3b show a detailed view of the air spring device from FIG. 2a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] FIGS. 1a and 1b show an air spring system 100 in accordance with a first preferred embodiment of the present invention. In particular, this is an air spring system 100 which is provided for cushioning a wheel axle 24 on a commercial vehicle, for example a semi-trailer. A wheel hub 7 and a brake disk 8 are attached, for example, on the wheel axle 24. Essential constituent parts of an air spring system 100 of this type are a link 2 and an air spring device 1. The link 2 is preferably attached, for example at its one end, to a vehicle body such that it can be pivoted about a pivot axis, and supports the wheel axle 24. In order to damp a translational movement, for example an up and down movement, of the wheel axle 24 during operation, the link 2 is attached via the air spring device 1 to a further region of the vehicle body, which further region is spaced apart from the pivot axis. In addition to the cushioning of the wheel axle 24, the air spring system 100 is also used to change a ride height position of a vehicle. Here, essential constituent parts of the air spring device 1 are preferably a piston element 3 and an air bellows element 4, it being possible for the air bellows element 4 and the piston element 3 to be displaced relative to one another. Here, in the case of a compression and rebound, the air bellows element 4 rolls on an outer face of the piston element 3. To this end, the air bellows element 4 is preferably manufactured from an elastic material, by way of which a folding movement can be brought about during the rolling. In addition, a damping action is brought about by virtue of the fact that a fluid, in particular air, flows to and from via a constricted cross section between a working volume or primary volume 11 which is provided by way of the air bellows element 4 and the piston element 3 and a secondary volume 12 or chamber which is configured in the piston. The vibrations which are introduced are damped on account of the constricted cross section and the associated friction.

[0032] The damping behavior of an air spring device 1 of this type is dependent on the available air volume. In order to increase the volume, it is therefore known to connect the working space to an additional container 9 which provides an additional volume. In particular, the additional container 9 and the air spring device 2 are connected fluidically via a connecting duct 10 in the mounted state. It is provided, in particular, that the air spring device 1 is attached on an upper side of the link 2, which upper side faces the chassis, whereas the additional container 9 is attached on a lower side of the link 2, which lower side faces away from the chassis. In order to avoid locking elements which fill the installation space, it is provided, in particular, that the link 2 has one or more engagement regions 21 in an interface region E, in which the air spring device 1 is attached to the link 2, which engagement region/regions interacts/interact in a positively locking manner with a positively locking element 53 of the air spring device 1, in particular of the piston element 3. In the exemplary embodiment which is shown, the positively locking elements 53 are a hook element which is arranged on an end side of the air spring device 2, in particular of the piston element 3, which end side faces the link 2 in the mounted state. It is provided, in particular, that the link-side engagement region 21 and the air spring device-side positively locking element configure a bayonet closure. Here, the connecting duct 10 is plugged through a corresponding opening 28 in the link 2, in order to achieve the connection to the additional container 9.

[0033] In order to avoid the air bellows element 4 deforming in the direction of the primary volume 11 in the case of a negative pressure which is configured in the primary volume 11, a sealing apparatus 13 is provided in the connecting duct 10 in the embodiment from FIG. 1. A negative pressure of this type can be produced, for example, when the vehicle body of a semi-trailer is lifted in the case of the attachment of the semi-trailer to a semi-trailer tractor, and the air spring device 1 and therefore the primary volume 11 are stretched. The negative pressure which is configured with respect to the surroundings necessitates a deformation of the air bellows element in the direction of the primary volume 11 or working volume, that is to say the air bellows element 4 collapses. In the case of subsequent lowering of the vehicle body of the semi-trailer, damage to the air spring device 1, in particular to the air bellows element 4, can occur as a consequence of the compression of the air spring device 1. In order to avoid this, the sealing apparatus 13 is provided in the connecting duct 10 in the embodiment which is shown in FIG. 1. Here, the sealing apparatus 13 is shown in a detailed view and, in addition to a main body 14, comprises a sealing element 15 which is formed on the circumference of the main body 14. The sealing element 14 is, in particular, a sealing lip which is directed with its outermost circumference as viewed in the radial direction or with its end 20 which faces away from the main body 14 toward the primary volume 11. As a result of said geometry of the sealing apparatus 13, it is possible in an advantageous way that the sealing element 13 is transferred, in a state in which it is mounted in the air spring device 1, from a sealed position, in which the sealing element 15 seals the primary volume 11 with respect to a secondary volume 12, into a released position, in which air passes the sealing element 15 when a pressure difference between the primary volume and the secondary volume, which pressure difference is set as a negative pressure in the primary volume 11 with respect to the secondary volume 12, exceeds a threshold value.

[0034] Here, FIG. 2a shows the sealing apparatus once again in the sealed position, whereas FIG. 2b illustrates the transition from the sealed position into the released position. Here, the + symbols which are provided with a circle symbolize a positive pressure, whereas the symbols which are provided with a circle are intended to symbolize a negative pressure. It is apparent from FIG. 2b, furthermore, that the sealing element 15 is bent in the released position in such a way that an air flow 18 can pass the sealing apparatus 13, in order thus to ensure a pressure equalization between the primary volume 11 and the secondary volume 12. In order to bring it about that the sealing element 15 is bent in the case of a defined threshold value for the negative pressure being exceeded, the length, the thickness and/or the material of the sealing element 15 are preferably adapted accordingly. In the embodiment which is shown, it is provided, in particular, that the length L2 (measured in the axial direction) of the sealing element 15 is greater than a thickness L1 (measured in the same direction) of the main body. Furthermore, it is conceivable that the main body 14 is of cylindrical configuration, or that the sealing apparatus 13 comprises an annular main body 14 which can be inserted into a circumferential cutout of a closure element 29. As a result, existing air spring devices 1 can be retrofitted with the above-described sealing apparatus 13 if they comprise a closure element 29 of this type with a receptacle for a seal.

[0035] Furthermore, it is provided that a ratio between an outermost diameter C of the main body 14 to an outermost diameter B of the sealing element 15 assumes a value of between 0.78 and 0.98, preferably of between 0.91 and 0.97, and particularly preferably of between 0.87 and 0.96.

[0036] FIGS. 3a and 3b show an air spring device 1 in accordance with a second preferred embodiment of the present invention. Here, the embodiment of FIG. 3 differs from that from FIGS. 1 and 2 substantially only with regard to the arrangement of the seal device 13. It is provided, in particular, that the sealing device 13 lies on the piston element 3, in particular on an upper side 23 of the piston element 3. The upper side 23 of the piston element 3 is preferably to be understood to mean that side of the piston element which faces away from the link 2 and faces the primary volume 11, in particular that side which lies opposite a head plate 5 of the air spring device. The upper side 23 is preferably of curved or funnel-shaped configuration; in particular, the upper side 23 is of curved or funnel-shaped configuration in the direction of the link 2 in the mounted state. That is to say, the upper side 23 runs, coming from the outermost circumference of the piston element 3, in the direction of the center obliquely in the direction of the link 2. Here, the connecting duct 10 is arranged concentrically in the piston element 3, the connecting duct 10 projecting from the link 10 to a less pronounced extent than the piston element 3 in a direction which runs parallel to the axial direction A. It is also conceivable that the upper side 23 of the piston element 3 runs obliquely substantially by 45 with respect to the link 2 or with respect to the axial direction A. The air bellows element 4 is preferably attached via a bead 27 to the upper side 23 of the piston element 3. It is provided, in particular, that the sealing element 15 is configured in such a way that, in the mounted state, the sealing element 15 runs at least partially parallel to the upper side 23. As a result, flat contact of the sealing element 15 on the upper side 23, in particular on a side wall 22 of the upper side 23, can be realized in an advantageous way, which flat contact has an advantageous effect on the sealing action. In addition, the insertion of the sealing apparatus is simplified, since the oblique course of the side wall 22 can serve as a guide. In order that an exchange of air with the secondary volume 12 (here, the volume between the piston element 3 and the connecting duct 10 or the outer surroundings of the piston element 3) can be realized, cutouts 19 and/or further cutouts are provided. Cutouts 19 are preferably provided in the upper side 23 of the piston element 3, in particular below the sealing apparatus 13, especially below the main body 14, as viewed in a direction which runs parallel to the axial direction A. Here, the term below is preferably to be understood such that the cutout 19 is arranged between the sealing apparatus 13 and the link 2. Furthermore, a cavity 51 or clearance is provided which is configured above the piston element 3 or between the piston element and the sealing apparatus. Moreover, further cutouts 19 are made in an outer wall 27 of the piston element 3, with the result that an exchange of air with the surroundings of the air spring device 1 can take place via the cutout 19 and the further cutout 19. A ratio between a spacing H1 (measured in the axial direction) of the further cutout 19 from the link 2 to the overall extent H2 of the piston element 3 preferably assumes a value of between 0.05 and 0.45, preferably of between 0.28 and 0.38, and particularly preferably of between 0.32 and 0.35. This advantageously ensures that the air bellows element does not accidentally cover the further cutout 19. Furthermore, it is conceivable that grills are integrated into the cutouts 19 or the further cutout 19. It can advantageously be avoided by means of the grills that foreign bodies can pass into the air spring device 1.

[0037] Furthermore, a stop element 17, preferably a bump rubber, is provided which lies on the connecting duct 10 and the upper side 23 of the piston element 3. In the case of moving together or compression, said stop element 17 bears against a head plate 5 of the air spring device 1. In the embodiment which is shown by way of example in FIG. 3, the seal apparatus 13 is integrated here into the stop element 17, in particular on that side which faces the link 2 in the mounted state. The number of components can advantageously be limited by way of the integration into the stop element 17.

LIST OF DESIGNATIONS

[0038] 1 Air spring device [0039] 2 Link [0040] 3 Piston element [0041] 4 Air bellows element [0042] 5 Head plate [0043] 7 Wheel hub [0044] 8 Brake disk [0045] 9 Additional container [0046] 10 Connecting duct [0047] 11 Primary volume [0048] 12 Secondary volume [0049] 13 Sealing apparatus [0050] 14 Main body [0051] 15 Sealing element [0052] 16 Inner side [0053] 17 Stop element [0054] 18 Air flow [0055] 19 Cutout [0056] 19 Further cutout [0057] 20 End [0058] 21 Engagement region [0059] 22 Side wall [0060] 23 Upper side [0061] 24 Axis [0062] 27 Outer wall [0063] 28 Opening [0064] 29 Closure element [0065] 51 Cavity [0066] 53 Positively locking element [0067] H1 Spacing [0068] H2 Overall extent [0069] A Axial direction [0070] C Diameter of the main body [0071] D Diameter of the sealing element [0072] E Interface region [0073] L1 Length of the sealing element [0074] L2 Thickness of the main body