Device for sealing an object

Abstract

Device (1) for sealing an object (2) to be sealed, comprising a sealing body (4) which has a sealing side (4a) facing the object (2) to be sealed and a rear side (4b) facing away from the object (2) to be sealed, wherein the sealing body (4) on the back side (4b) has at least one element (6) that changes the stiffness of the sealing body (4) and changes the surface pressure between the sealing body (4) and the object (2) to be sealed, wherein several elements (6) that change the stiffness of the sealing body (4) are arranged distributed around the circumference of the sealing body (4), and wherein the elements (6) that change the stiffness of the sealing body (4) extend obliquely to a longitudinal axis of the sealing body (4), characterized in that at least one of the elements (6) arranged distributed around the circumference of the sealing body (4) and changing the stiffness of the sealing body (4) runs in an oblique direction to the longitudinal axis of the sealing body (4) in the opposite direction to the other elements (6) changing the stiffness of the sealing body (4).

Description

[0001] The invention relates to a device for sealing an object to be sealed, in particular for sealing a rotating shaft, with a sealing body which has a sealing side facing the object to be sealed and a rear side facing away from the object to be sealed, according to the type defined in more detail in the preamble of claim 1.

[0002] A wide variety of designs of such sealing devices are known from the prior art. Some of these known devices are discussed in more detail below: DE 10 2006 058 699 A1 describes a cover or sealing element for sealing between a component defining a passage opening for a shaft and the shaft passing through the passage opening. The sealing element comprises a dynamic sealing area for sealing against the shaft and a static sealing area for static contact with the component. The dynamic sealing area is formed from an elastomer material and comprises a sealing section that seals along a shaft section, the inner casing of which comprises a return structure for returning the leakage fluid to a space to be sealed.

[0003] DE 10 2007 036 625 A1 describes a similar sealing element for sealing a rotating shaft at a passage opening of a housing part with a stiffening part and an elastomer part connected to the stiffening part, which has a first sealing area for a statically sealing fit against the housing part and a second sealing area with a sealing section designed and provided for a sealing fit against the shaft, which sealing section comprises a thread-like return structure for returning a leakage fluid into a space to be sealed.

[0004] DE 10 2010 042 555 A1 describes a radial shaft seal which has a stiffening ring and an elastomer part connected to the stiffening ring, which has a sealing lip with a first sealing section provided with a thread-like return structure for the return of a leakage fluid in a rotating shaft and a second sealing section which has a circular cylinder jacket-shaped sealing surface, which in turn has a microstructure, for gas-tight contact with a stationary shaft.

[0005] From DE 10 2010 061 819 A1, a radial shaft sealing ring with a stiffening ring and an elastomer part connected to the stiffening ring is known, which has a dynamic sealing lip with a radial sealing lip section and an axial sealing lip section, wherein the axial sealing lip section has a sealing edge for a sealing engagement with a shaft, which sealing edge is arranged on an inner jacket wall of the axial sealing lip section facing the shaft.

[0006] WO 2012 / 095227 A1 describes a radial shaft seal with a reinforcing ring and an elastomer part connected to the reinforcing ring, which carries a dynamic sealing lip having a sealing edge made of PTFE that rests against a shaft sealed by the radial shaft seal.

[0007] From DE 10 2010 026 157 A1, a drive shaft of an axial piston machine is known which is sealed by means of a radial shaft sealing system which has a radial shaft sealing ring and a counter-running surface whose surface has a hydrodynamic return structure provided with a hard, diamond-like surface coating.

[0008] A release bearing for a friction clutch designed as a diaphragm spring clutch is described in DE 10 2009 049 466 A1. This bearing has a bearing interior filled with bearing grease, which is axially sealed by a seal that is rigidly attached to the bearing outer ring and rests against a sealing surface of the bearing inner ring with the sealing edge of a sealing lip. To increase the sealing effect, the sealing lip of the seal is provided with an annular return structure arranged axially adjacent to the sealing edge and operatively connected to the associated sealing surface.

[0009] A mechanical seal for sealing the passage of a rotating shaft through a wall is known from EP 0 592 462 B1. The mechanical seal has return flow structures with several return flow points located at geometrically defined positions.

[0010] DE 101 09 320 A1 describes a radial shaft seal with a sealing element made of plastic, in particular a PTFE compound, which has a sealing lip, a portion of which lies sealingly against the surface of a shaft on the medium side. A pressure device is provided on the medium side of the sealing lip, which presses the portion of the sealing lip against the surface of the shaft with a radially inward force.

[0011] The known radial shaft seals are therefore often equipped with so-called return structures, which are intended to redirect fluid entrained by the rotating shaft axially toward the media side or the side to be sealed, thus resulting in a return flow of the fluid and thus a seal in the dynamic state. This principle sometimes works with rubber radial shaft seals even without explicitly created return structures, since the rubber material itself forms these structures due to friction.

[0012] The known sealing rings equipped with such return structures on the sealing side facing the object to be sealed, or sealing rings in which the return structures form spontaneously, are usually made of a rubber-based material. However, the problem with rubber sealing rings is that they become very hot due to the friction with the rotating shaft under the sometimes required high contact forces, and can be damaged.

[0013] For this reason, some attempts are being made to use sealing rings made of other, particularly more heat-resistant materials, such as polytetrafluoroethylene. Examples of this are also described above. Since seals made of these materials are more thermally and chemically resistant, but also significantly harder than rubber sealing rings, these return structures do not arise naturally in these sealing rings but must be machined into them, which leads to very demanding manufacturing and assembly requirements. Furthermore, the higher hardness of this material can result in the sealing side or contact surface not fully contacting the object to be sealed, even with relatively small geometric deviations from the desired state, and thus optimal sealing is not achieved.

[0014] According to the state of the art, spiral grooves are sometimes used in such PTFE sealing rings to return the fluid. While these spiral grooves work quite well on rotating shafts, i.e., in the case of dynamic sealing, leaks can occur on stationary shafts, i.e., in the case of static sealing, because the fluid can pass through the spiral grooves from the fluid or media side to the air side.

[0015] DE 102 33 396 A1 describes a shaft seal and a method for sealing a shaft.

[0016] A generic device is known from JP4411685 B2.

[0017] It is an object of the present invention to provide a device for sealing an object to be sealed, in particular for sealing a rotating shaft, which ensures reliable sealing in a wide variety of operating conditions.

[0018] According to the invention, this object is achieved by the features mentioned in claim 1.

[0019] The element according to the invention, arranged on the back of the sealing body and modifying its rigidity, achieves an uneven distribution of the surface pressure in the sealing gap between the sealing body of the device according to the invention and the object to be sealed. This uneven distribution of the surface pressure and the pressure differences within the sealing gap that arise in the dynamic state result in very narrow and narrowly tapered gaps between the sealing body and the object to be sealed, through which the fluid entrained by the rotating shaft is deflected in the axial direction and can thus be conveyed back to the fluid or media side.

[0020] The described gap formation between the sealing body and the object to be sealed can also only occur in a dynamic state, for example, during shaft rotation. This allows for a very effective seal in dynamic applications with relatively little design effort.

[0021] Due to the inventive arrangement of the element that changes the rigidity of the sealing body on the back of the sealing body, i.e. on the side thereof opposite the sealing side, the surface of the sealing side itself is not changed, so that in the static application case, i.e. for example in the switched-off state of a machine equipped with the device according to the invention, it lies completely against the object to be sealed and a high level of tightness is achieved.

[0022] Due to its simple structural design, the solution according to the invention can be used for a wide variety of applications, as it can be easily adapted to the respective requirements.

[0023] According to the invention, several elements that vary the rigidity of the sealing body are distributed around the circumference of the sealing body. This allows a uniform sealing effect to be achieved around the entire circumference of the object to be sealed, which is particularly advantageous in the case of a rotating shaft.

[0024] To direct the fluid flow away from the peripheral edge, the elements that modify the stiffness of the sealing body can be arranged at an angle to a longitudinal axis of the sealing body. The term "at an angle to a longitudinal axis of the sealing body" encompasses both a straight and an arcuate or curved path for the element that modify the stiffness of the sealing body.

[0025] Furthermore, if at least one of the elements arranged around the circumference of the sealing body and changing the stiffness of the sealing body extends obliquely to the longitudinal axis of the sealing body in an opposite direction to the other elements changing the stiffness of the sealing body, the device can be used for two different directions of rotation of a rotating shaft.

[0026] An improvement in static sealing is achieved when the elements that modify the stiffness of the sealing body are spaced from a peripheral edge of the sealing body. In this case, the peripheral edge of the sealing body remains unchanged, ensuring effective sealing in all applications. However, this spacing is not mandatory, and the elements that modify the stiffness of the sealing body could also extend to a peripheral edge of the sealing body.

[0027] In a very simple embodiment of the invention, it can be provided that elements which change the rigidity of the sealing body are formed by changing the material thickness of the sealing body.

[0028] A particularly relevant design in practice can be the design of the elements that modify the rigidity of the sealing body as a recess. Such recesses can be incorporated into the sealing body during its manufacture and therefore require very little manufacturing effort.

[0029] In this case, it has proven particularly advantageous with regard to the effect of the elements that change the stiffness of the sealing body if the recess has a depth of 30 to 90% of the material thickness of the sealing body.

[0030] Alternatively, or in addition to the design of the elements that modify the rigidity of the sealing body as a recess, the elements that modify the rigidity of the sealing body can be designed as raised portions. Such raised portions can also be created during the production of the sealing body and have the desired effect on the surface pressure between the sealing body and the object to be sealed.

[0031] The desired sealing effect can be achieved if the increase exceeds the material thickness of the sealing body by 25 to 100%.

[0032] In addition to or as an alternative to changing the material thickness of the sealing body, it is also possible for the elements that modify the rigidity of the sealing body to be formed from a material that differs from the material of the sealing body. Such a material exchange can also influence the surface pressure between the sealing body and the object to be sealed. Combinations of the various embodiments for forming the elements that modify the rigidity of the sealing body on one and the same sealing body are also possible.

[0033] A particularly advantageous embodiment of the invention with regard to conveying the fluid in the desired direction is achieved when the elements that modify the rigidity of the sealing body widen away from a peripheral edge of the sealing body. In principle, a parallel extension of the two lateral edges of the elements that modify the rigidity of the sealing body is also conceivable.

[0034] Furthermore, the sealing body can be made of polytetrafluoroethylene. Since problems with fluid return often occur with PTFE seals, the solution according to the invention is particularly interesting for such seals. In principle, the solution according to the invention can also be used with other materials commonly used for seals.

[0035] Furthermore, if the sealing body is essentially smooth on the sealing side, this represents a simple manufacturing design and, at the same time, ensures a good basic seal at the area to be sealed. The term "smooth" refers to a surface finish on the sealing side of the sealing body that does not have any embedded or applied structures. In principle, this is a flat sealing side in its original state, disregarding the curvature or bending line of the sealing body resulting from use or assembly.

[0036] In the following, embodiments of the invention are shown in principle with reference to the drawing.

[0037] It shows: Fig. 1 shows a first embodiment of the device according to the invention; Fig. 2 an enlarged view along the line II-II of Fig. 1; Fig. 3 a perspective view of a second embodiment of the device according to the invention; Fig. 4 shows the contact area between the device according to the invention and the object to be sealed; Fig. 5 shows a third embodiment of the device according to the invention; Fig. 6 an enlarged view along line VI of Fig. 5; Fig. 7 shows a fourth embodiment of the device according to the invention; Fig. 8 an enlarged view along line VIII of Fig. 7; Fig. 9 shows a fifth embodiment of the device according to the invention; Fig. 10 an enlarged view along the line X from Fig. 9; Fig. 11 shows a sixth embodiment of the device according to the invention; Fig. 12 an enlarged view along line XII of Fig. 11; and Fig. 13 an alternative to the embodiment of Fig. 12.

[0038] Fig. 1 shows a device 1 for sealing an object 2 to be sealed, in the present case a shaft 2a rotating about a longitudinal axis 3. The device 1 has a sealing body 4, which has a sealing side 4a facing the object 2 to be sealed and partially touching it, and a rear side 4b facing away from the object 2 to be sealed. The sealing body 4 is held at its end facing away from the object 2 in a component 5 that is only indicated schematically. The component 5 can be, for example, a housing in which the rotating shaft 2a is mounted. Of course, other installation options or types of application of the device 1 are also conceivable.

[0039] The Fig. 1, Fig. 4, Fig. 6, Fig. 8 and Fig. The sleeve-like installation situation of the device 1 shown in Figure 10 is to be considered purely exemplary, and the device 1 can, in principle, be installed or arranged in a wide variety of ways with regard to the installation direction and its arrangement relative to the component 5 and the object 2 in order to achieve the sealing described below. In principle, all geometric shapes of the sealing body 4 are conceivable, in which the circumferential forces on the object 2 arise from an expansion of the sealing body 4.

[0040] As in Fig. 1 and especially in the perspective representation of Fig. As can be seen in Figure 3, the sealing body 4 has a plurality of elements 6 on the rear side 4b that change the rigidity of the sealing body 4. The elements 6 that change the rigidity of the sealing body 4, which for the sake of simplicity are sometimes referred to simply as elements 6 below, can be designed in various ways, some of which are described below. In all embodiments of the device 1 described herein, a plurality of elements 6 are provided. The elements can also be referred to as "back structures" since they are located on the rear side 4b of the sealing body 4.

[0041] The area of ​​the sealing body 4 which is in contact with the object 2 to be sealed experiences stiffness jumps due to the elements 6, which lead to an influence on the surface pressure of the sealing body 4 on the object 2 to be sealed and thus to an influence on the gap formation between the sealing body 4 and the object 2 to be sealed. All embodiments therefore have in common that the elements 6 are designed such that they change the surface pressure between the sealing body 4 and the object 2 to be sealed. A changing surface pressure therefore results across the area of ​​the sealing body 4 which is in contact with the object 2 to be sealed. The elements 6 each locally influence the surface pressure of the sealing body 4 on the object 2 to be sealed, so that a certain wedge gap is created or formed in this area.When the shaft 2a rotates, a drag flow in its circumferential direction forms through which a fluid that is to be held in a specific area by the device 1 can be conveyed back to this area. The fluid can be, for example, oil or another liquid, or possibly also a gas. The illustration in the figures shows an area to the left of the device 1. This area forms, for example, the interior space 5a of the housing or component 5.

[0042] All embodiments also have in common that the sealing body 4 is essentially flat on the sealing side 4a. This is not absolutely necessary, and the sealing body 4 could also have certain structures on the sealing side 4a.

[0043] Preferably, the sealing body 4 is made of polytetrafluoroethylene (PTFE). However, the elements 6 that modify the stiffness of the sealing body 4 could, in principle, also be used in sealing bodies 4 made of other materials, such as elastomers. For example, the sealing body 4 could also be made of polyurethane.

[0044] In Fig. 3 shows that several elements 6 are arranged around the circumference of the sealing body 4, which change the stiffness of the sealing body 4. The number and distribution of the elements 6 according to Fig. 3 is, however, to be regarded as purely exemplary and can be implemented differently depending on the respective application.

[0045] Furthermore, in all embodiments illustrated in the figures, the elements 6 are arranged such that they are spaced apart from a peripheral edge 7 of the sealing body 4 facing the interior 5a of the component 5. However, this is not absolutely necessary, and the elements 6 could also extend to the peripheral edge 7 of the sealing body 4 if necessary. The spacing of the elements 6 from the peripheral edge 7 prevents fluid from escaping, since the sealing body 4 rests evenly against the object 2 to be sealed in the region of the peripheral edge 7.

[0046] In the Fig. 1 to 3 and the Fig. 4 and Fig. In the embodiments shown in Figure 5, the elements 6 are formed by changing the material thickness of the sealing body 4.

[0047] In the design of the Fig. 1 to 3, the elements 6 that change the rigidity of the sealing body 4 are designed as a recess 6a. The at least one recess 6a or the recesses 6a distributed around the circumference of the sealing body 4 result in a reduction in the rigidity of the sealing body 4 in this area. Due to the recess 6a and the resulting reduction in rigidity in the area thereof, the respective area between the elements 6 has a higher rigidity.

[0048] Preferably, the recess 6a has a depth of 30 to 90% of the material thickness of the sealing body 4. For example, if the sealing body 4 has a material thickness of 2 mm, the depth of the recess 6a is 1 to 1.6 mm. The remaining material of the sealing body 4 in the region of the sealing side 4a, which is in contact with the object 2 to be sealed, is therefore still 0.4 to 1 mm in this case. These are, of course, purely exemplary specifications.

[0049] Such recesses 6a forming the elements 6 can be created during the manufacture of the sealing body 4, i.e., during its primary forming. The primary forming of the sealing body 4 can be achieved, for example, by sintering or injection molding. Alternatively or additionally, the elements 6 can also be created by embossing, forming, machining, or laser processing.

[0050] In Fig. 2, the change in surface pressure between the sealing body 4 and the object 2 to be sealed, resulting from the elements 6, is shown in an enlarged manner using isobars, i.e. lines of equal pressure or, in this case, equal surface pressure. Fig. 2 which are characterized by the Fig. 1. From the isobars it can be seen that due to the pressure gradient between the sealing body 4 and the object 2 to be sealed, the escaping fluid or fluid tending to escape can be redirected towards the interior space 5a and conveyed back. The gradient of the elements 6 is also shown in the enlargement of Fig. 2. Furthermore, this trend also emerges from Fig. 1 and the design of the Fig. 1 to 3 also from the perspective representation of Fig. 3. It can be seen that the elements 6 which change the stiffness of the sealing body 4 widen away from the peripheral edge 7 of the sealing body 4. Conversely, the elements 6 taper, or in the embodiment of the Fig. 1 to 3, the recess 6a extends toward the peripheral edge 7. This is a particularly effective embodiment of the elements 6 that modify the rigidity of the sealing body 4; however, embodiments are also conceivable in which the two lateral edges of the elements 6 that modify the rigidity of the sealing body 4 run parallel to one another.

[0051] Furthermore, the recesses 6a extend obliquely to the longitudinal axis 3 of the rotating shaft 2a, which also represents the longitudinal axis of the sealing body 4. This configuration of the elements 6 creates a wedge-shaped gap between the sealing body 4 and the object 2 to be sealed, allowing fluid to be conveyed back. In other words, this configuration of the elements 6 directs the fluid flow toward the peripheral edge 7. According to the invention, individual elements 6 are arranged opposite to the illustrated oblique position, so that the device 1 can be used for two different directions of rotation of the rotating shaft 2a.

[0052] The ratio of the height of the resulting sealing gap to its length along the longitudinal axis 3, which depends on the length of the respective element 6 along the longitudinal axis 3, can be very small and can, for example, be between 1:100 and 1:10000. The length of the element 6 along the longitudinal axis 3 can therefore be several mm.

[0053] Fig. Figure 4 shows the contact area between the device 1 or the sealing body 4 and the object 2 to be sealed or the shaft 2a. Due to the above-described back structures on the back 4b of the sealing body 4, an uneven pressure distribution results, which in Fig. 4 is marked as isobar A. The fluid entrained by the rotation of the shaft 2a is axially deflected by the uneven pressure distribution and can be conveyed toward the space to be sealed, in this case the sealing side, which is indicated by the arrows labeled "B." This ensures the sealing effect in the dynamic state, i.e., during rotation of the shaft 2a.

[0054] In the Fig. 5 and Fig. In the embodiment shown in Figure 6, the elements 6 that modify the rigidity of the sealing body 4 are formed as elevations 6b. The elevations 6b distributed around the circumference of the sealing body 4 result in an increase in the rigidity of the sealing body 4 in this area. In the case of a higher rigidity, a higher surface pressure of the sealing body 4 on the object 2 to be sealed results, and the return structures are formed between the elements 6.

[0055] In a similar manner to the recesses 6a according to the embodiments of the Fig. 1 to 3, the elevations 6b also widen away from the peripheral edge 7. Furthermore, the elevations 6b also extend obliquely to the longitudinal axis 3 of the rotating shaft 2a, which also represents the longitudinal axis for the sealing body 4.

[0056] Preferably, the elevations 6b exceed the material thickness of the sealing body 4 by 25 to 100%, so that the desired effect regarding the change in the surface pressure of the sealing body 4 on the object 2 to be sealed is achieved. For a sealing body 4 with a material thickness of 2 mm, this means that the height of the elevation 6b is 0.5 to 2.0 mm. The material thickness of the sealing body 4 in the area of ​​the elevations 6b in this case is therefore 2.5 mm to 4.0 mm. Of course, these specifications are to be considered purely exemplary.

[0057] Fig. 6 shows similar to Fig. 2 shows the isobars, which indicate the surface pressure between the sealing body 4 and the object 2 to be sealed. This illustration also shows the course of the elevations 6b forming the elements 6.

[0058] The elevations 6b, similar to the depressions 6a, can already be created during the primary forming of the sealing body 4 described above. The elevations 6b could also be created by applying an additional material to the sealing body 4.

[0059] In the Fig. 7 and Fig. In the embodiment of the device 1 shown in Figure 8, the elements 6 that change the rigidity of the sealing body 4 are formed by a material 6c that differs from the material of the sealing body 4. In the present case, the material 6c is a material with a higher rigidity than the material of the sealing body 4, resulting in an increase in the rigidity of the sealing body 4 in the region of the elements 6. This allows a similar influence on the surface pressure between the sealing body 4 and the object 2 to be sealed as achieved by the elevations 6b.

[0060] To introduce the material 6c, for example, a recess can be created in the sealing body 4 and the material 6c can be introduced into it. However, it is also possible to introduce the material 6c into the sealing body 4 during its manufacture, for example by means of casting, sintering, vulcanization, or another suitable process. If necessary, fiber materials can also be used for the material 6c, which can also be introduced into the sealing body 4 during the primary forming process. In a similar way to the elevations 6b, the material 6c could also be created by introducing an additional material into the sealing body 4.

[0061] In Fig. 8 are analogous to Fig. 2 shows the isobars from which the surface pressure between the sealing body 4 and the object 2 to be sealed as well as the course of the elements 6 which widens obliquely to the longitudinal axis 3 and away from the peripheral edge 7 can be derived.

[0062] A combination of the embodiments of the Fig. 5 and Fig. 6 on the one hand and the Fig. 7 and Fig. 8 on the other hand, in the Fig. 9 and Fig. 10. In this case, the elements 6 that change the rigidity of the sealing body 4 are again formed by the elevation 6b, wherein the elevations 6b in this case comprise the material 6c or consist of the material 6c. This in turn results in an increase in rigidity in the region of the elements 6 distributed around the circumference of the sealing body 4, with the effect on the surface pressure between the sealing body 4 and the object 2 to be sealed, as already described above. By using a material 6c with a higher rigidity than the base material of the sealing body 4, the height of the elevation 6b can possibly be reduced.

[0063] In Fig. 10 also shows the isobars representing the surface pressure between the sealing body 4 and the object 2 to be sealed, and the course of the elements 6, which here too is designed obliquely to the longitudinal axis 3 and widening away from the peripheral edge 7, can be seen.

[0064] The Fig. The embodiment of the device 1 shown in Figures 11 to 13 is similar to that according to Fig. 7 and Fig. 8, since the elements 6 that change the rigidity of the sealing body 4 are in turn formed from the material 6c that differs from the material of the sealing body 4. Depending on the material used, a reduction or increase in the rigidity of the sealing body 4 can be achieved in the respective area. Using a material 6c with a lower rigidity than the material of the sealing body 4 results in a reduction in rigidity in the area of ​​the respective element 6. In contrast, using a material 6c with a higher rigidity than the material of the sealing body 4 results in an increase in rigidity in the area of ​​the respective element 6.

[0065] Here, using the isobars already described above, Fig. 12 the case of an increase in stiffness and thus an increase in the surface pressure between the sealing body 4 and the object 2 to be sealed and Fig. 13 shows the case of a reduction in stiffness and thus a reduction in the surface pressure between the sealing body 4 and the object 2 to be sealed. Also in the embodiment of the Fig. 11, Fig. 12 and Fig. 13, the elements 6 widen away from the peripheral edge 7 and are also arranged obliquely to the longitudinal axis 3.

[0066] The details of the embodiments of the sealing body 4 described herein can, in principle, be combined with one another in any desired way, unless obvious reasons speak against a particular combination. It would therefore also be possible to design some of the elements 6 on one and the same sealing body 4 as depressions 6a and another part as elevations 6b. A combination with a material 6c that differs from the material of the sealing body 4 would also be conceivable. The number, arrangement, and design of the elements 6 can be adapted to the respective application.

Claims

[1] Device (1) for sealing an object (2) to be sealed, comprising a sealing body (4) which has a sealing side (4a) facing the object (2) to be sealed and a rear side (4b) facing away from the object (2) to be sealed, wherein the sealing body (4) has on the back (4b) at least one element (6) which changes the rigidity of the sealing body (4) and which changes the surface pressure between the sealing body (4) and the object (2) to be sealed, wherein several elements (6) which change the rigidity of the sealing body (4) are arranged distributed around the circumference of the sealing body (4), and wherein the elements (6) which change the rigidity of the sealing body (4) run obliquely to a longitudinal axis of the sealing body (4), characterized bythat at least one of the elements (6) arranged distributed around the circumference of the sealing body (4) and changing the rigidity of the sealing body (4) runs obliquely to the longitudinal axis of the sealing body (4) in an opposite direction to the other elements (6) changing the rigidity of the sealing body (4). [2] Device according to claim 1, characterized by that the elements (6) which change the rigidity of the sealing body (4) are spaced from a peripheral edge (7) of the sealing body (4). [3] Device according to claim 1 or 2, characterized by that the elements (6) which change the rigidity of the sealing body (4) are formed by changing the material thickness of the sealing body (4). [4] Device according to claim 3, characterized by that the elements (6) which change the rigidity of the sealing body (4) are designed as depressions (6a). [5] Device according to claim 4, characterized by that the recess (6a) has a depth of 30 to 90% of the material thickness of the sealing body (4). [6] Device according to claim 3, 4 or 5, characterized by that the elements (6) which change the rigidity of the sealing body (4) are designed as elevations (6b). [7] Device according to claim 6, characterized by that the elevation (6b) exceeds the material thickness of the sealing body (4) by 25 to 100%. [8] Device according to one of claims 1 to 7, characterized by that the elements (6) which change the rigidity of the sealing body (4) are formed by a material (6c) which is different from the material of the sealing body (4). [9] Device according to one of claims 1 to 8, characterized by that the elements (6) which change the rigidity of the sealing body (4) widen away from a peripheral edge (7) of the sealing body (4). [10] Device according to one of claims 1 to 9, characterized by that the sealing body (4) comprises polytetrafluoroethylene. [11] Device according to one of claims 1 to 10, characterized by that the sealing body (4) is substantially smooth on the sealing side (4a).

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