WO2008037448A1

WO2008037448A1 - Ring filter insert for a filter

Info

Publication number: WO2008037448A1
Application number: PCT/EP2007/008369
Authority: WO
Inventors: Marcel Borgmann
Original assignee: Hengst Gmbh & Co. Kg
Priority date: 2006-09-26
Filing date: 2007-09-26
Publication date: 2008-04-03
Also published as: DE202006014784U1

Abstract

The invention relates to a ring filter insert (1) for a filter for filtering a fluid medium, especially air or oil or fuel for an internal combustion engine, wherein the ring filter insert (1) has two end disks (11) and a filter body (10) arranged between them, wherein at least one of the end disks (11) has a connection orifice (13) with which the ring filter insert (1) can be attached to a connection nozzle (30) of the filter, and at least one elastic-flexible radial sealing ring (20) made of plastic being provided between the connection orifice (13) and the connection nozzle (30). The novel ring filter insert (1) is characterized in that the radial sealing ring (20) is an annular body composed of an elastomer with hollow pockets (21) arranged in its interior.

Description

Description :

Ring filter insert for a filter

A ring filter insert for a filter for filtering a fluid medium, in particular air or oil or fuel for an internal combustion engine, wherein the ring filter insert comprises two end disks and a filter material body arranged between them, wherein at least one of the end disks has a connection opening with which the ring filter insert on a connecting piece of the Filter is attachable, and wherein between the connection opening and the connecting piece at least one elastic-flexible radial sealing ring made of plastic is provided.

Ring filter cartridges of the type mentioned are generally known due to their widespread use, especially on internal combustion engines of motor vehicles. The ring filter insert of a filter is a replaceable part that has to be exchanged for a fresh filter insert after a certain period of operation. So that this replacement can take place with the least possible effort, the ring filter insert is usually attached with the interposition of an elastic-flexible radial seal on a filter-side connecting piece. As a radial sealing ring, an O-ring has hitherto usually been used which, in its unloaded state, has a round cross section and which, in an annular groove, has an appropriate axial height and radial depth at the inner end. nenumfang the connection opening of the ring filter insert is inserted.

It is favorable when using an O-ring that this is a standardized component and is available in many different sizes on the market. However, a disadvantage is considered in the known ring filter insert that the O-ring can bridge only a relatively small gap width between the outer circumference of the connecting piece and the inner circumference of the connection opening of the ring filter insert. Therefore, it is necessary that in the production of both the ring filter insert and the filter relatively tight tolerances on the one hand at the inner diameter of the connection opening and on the other hand be complied with the outer diameter of the connecting piece, resulting in an increased production cost. In addition, the attachment of the ring filter insert with the interposition of the O-ring requires a relatively high effort, because the O-ring is not compressible in itself, but must deform within its annular groove in itself. This complicates handling when changing the ring filter insert. Finally, it should be noted as a disadvantage that it can happen relatively easily that the O-ring when attaching the ring filter insert on its connection piece moves out of the annular groove, whereby a reliable sealing of the ring filter insert is no longer guaranteed on its connection piece.

From EP-AI 354 617 a filter element is known which has the features mentioned. The radial sealing ring is designed here as a lip seal, wherein a sealing lip integrally formed with the rest of the sealing ring forms the radially inner, cooperating with the connecting piece part of the sealing ring. Between the sealing lip and the rest of the sealing ring is a circumferential, axially outwardly open, in cross-section V-shaped groove, which allows the radial movement of the sealing lip required for the sealing function relative to the rest of the sealing ring. In the course of the groove a few, widely spaced circumferentially ribs may be integrally provided with the remaining sealing ring, which are to serve to maintain the shape of the sealing lip and to adjust the flexibility of the sealing lip.

In order for a sealing ring of the abovementioned type to be able to ensure reliable and permanently reliable sealing, it is necessary to maintain relatively tight tolerances in the manufacture of the filter insert, its connection-side end plate and the sealing ring, which is preferably integral therewith. In particular, there is a risk that the largely free radially inwardly projecting sealing lip fatigued over time, so that their restoring force decreases so much that the sealing contact of the sealing lip on the connection piece is no longer safe. This can lead to leaks after some use of the filter cartridge, resulting in an undesirable and inadmissible transfer of dirty medium to the clean side of the filter.

For the present invention, therefore, the object is to provide a ring filter insert of the type mentioned above, which avoids the disadvantages mentioned above and with the particular reliable sealing is achieved even with larger tolerances in terms of dimensions of connection port and connecting piece and in which the handling is easy and safe when changing the ring filter insert. The solution of this object succeeds according to the invention with a ring filter insert of the type mentioned, which is characterized in that the radial seal is an annular body made of an elastomer having arranged in its interior hollow pockets.

With the invention it is achieved that the ring filter insert reliably seals even with relatively large tolerances in the dimensions of connection opening and connecting piece, wherein the attachment and detachment of the ring filter insert requires only relatively small forces. At the same time, however, a secure seal is ensured. This is achieved in that the radial seal due to the hollow pockets arranged in its interior has a very high overall elasticity, so that when attaching the filter element to the connecting piece of the radial seal on its inner circumference over relatively large radial Wegstecken moves outwardly and thereby compressed in itself can be and automatically resets over correspondingly large radial distances due to its elasticity and flexibility. This also larger and especially different sized gap widths between the outer circumference of the connection piece and the inner circumference of the connection opening can be reliably sealed. Both the filter element and the associated connecting piece of the filter can therefore be manufactured with lower requirements for their dimensional accuracy, which simplifies and reduces their cost. By arranging hollow pockets in the radial sealing ring, material for the radial sealing ring is saved, which reduces the material costs for the radial sealing ring. At the same time, the time required for the production of the radial sealing ring is reduced because the pockets accumulate material in the Avoid radial seal and associated longer cooling and solidification times.

In a preferred further embodiment, it is provided that the pockets run parallel to one another in the axial direction of the annular filter insert and are arranged at a distance from one another in the circumferential direction of the radial sealing ring. This arrangement of the pockets is particularly favorable both in terms of elasticity properties of the radial seal and in terms of its production.

In order to support a secure and permanently tight fit of the filter cartridge on the connecting piece, it is further proposed that the pockets have on their radially inner side and / or on their radially outer side an axially corrugated surface contour. In this way, material thickening of the sealing ring is effected in one or more desired areas, which reinforce the restoring force of the sealing ring and thus make his seat on the connecting piece stronger.

Preferably, it is further provided that the corrugated surface contour is formed by an integrally formed on the radially inner side or on the radially outer side of the pockets wave crest and that the other side of the pockets is formed in a straight line in the axial direction. As a result, with full achievement of the desired function, the production of the sealing ring is easy.

A further embodiment provides that the corrugated surface contour of the pockets seen in the circumferential direction of the radial sealing ring is formed continuously. In this embodiment, a maximum possible reinforcement of the restoring force of the sealing ring is achieved. An alternative embodiment provides that the corrugated surface contour of the pockets in the circumferential direction of the radial sealing ring is designed to be interrupted. In this embodiment, a targeted and metered increase in the restoring force of the sealing ring is possible, wherein the restoring force increase is the lower, the greater the interruptions in the corrugated surface contour.

To achieve a particularly good sealing effect is further preferred that the radial sealing ring on its radially inwardly facing, cooperating with the connecting piece side has a surface contour with a plurality of axially spaced apart, circumferential sealing zones. In contrast to an O-ring, two or even more sealing zones can be provided on the radial sealing ring of the ring filter insert according to the invention, which ensures a particularly high reliability of the seal.

In this case, the surface contour on the radially inner side of the radial sealing ring in the axial direction is preferably wavy with at least two wave crests pointing radially inwards, each of which forms a sealing zone. The wavy contour avoids sharp corners and edges, which facilitates the insertion and removal of the ring filter insert on or from the connection piece. In addition, the arrangement of the hollow pockets with the high elasticity achieved thereby allows relatively large undercuts in a mold in which the radial seal is made, whereby comparatively simple shapes can be used which do not require complicated slides or inserts. Furthermore, it is expediently provided that the radial sealing ring has on its outer circumference a contact contour, with which the radial sealing ring is applied in an assembled state to a radially outwardly surrounding support surface of the associated end plate. In this way, the in itself very elastic and flexible radial sealing ring radially outside completely surrounded by a part of the end plate forming support surface, so that the radial seal can not dodge radially outward when the ring filter insert is placed on the associated connection piece. Of course, there is the support surface or the end plate of a material that is dimensionally stable under the action of the forces occurring in comparison to the material from which the radial seal.

In order to secure the radial seal relative to the rest of the ring filter insert in the axial direction, the invention also proposes that the radial seal on its axially facing the filter material body facing side has a contact contour with which the radial seal in an assembled state on an axially supporting support surface of the associated end plate rests.

In order to make the radial seal absolutely captive and always correctly position it on the ring filter insert, according to a development of the ring filter insert of the radial seal may be molded onto the associated end plate.

An alternative refinement of the annular filter insert provides that the end disk having the radial sealing ring consists of a plastic and that the front disk and the radial sealing ring are jointly produced in a two-component injection molding process and thereby are connected to each other. Such a manufactured ring filter insert is particularly economical because the production cost is particularly low and because in particular all assembly steps for attaching the sealing ring omitted.

Alternatively, the radial seal may be a separately manufactured injection molded part. In this embodiment, the radial seal is then connected manually or by means of an automatic mounting device with the associated end plate of the ring filter insert.

It can be provided that the separately manufactured radial seal is releasably connected to the associated end plate. In this case, it is possible to replace it in case of damage to the radial seal this further use of the other ring filter insert.

Thus, when releasably connected to the associated end disc radial seal this is still held sufficiently secure on the end plate, the invention also proposes that the radial seal having end plate has a radially inwardly open sealing ring receptacle, in which the separately manufactured radial seal under fixing both in Axial direction and in the radial direction can be inserted to the outside.

If an interchangeability of the radial seal is not desired, the separately manufactured radial seal with the associated end plate fixedly connected, in particular glued or welded, be. In this embodiment, the radial seal is captive and secured by the fixed connection in its position on the end plate. In order to exclude disturbing sink marks, in particular on the radially inner side with one or more sealing contours, the invention proposes that a first material thickness of the radial sealing ring between its pockets and its outer circumference and a second material thickness of the radial sealing ring in the region of material bridges between two adjacent pockets are the same size. This consistent material thickness also reduces the cycle time of the radial seal in the production tool. Also, a delay of the sealing ring is avoided in this way. The desired elasticity properties of the radial sealing ring can be adjusted by varying the material thicknesses in the desired manner and optimized for the particular application.

With regard to the shaping of the hollow pockets in the radial seal, there is a great deal of freedom. The pockets preferably have a polygonal, in particular hexagonal or rectangular or square, outline or a round or oval or elliptical outline in a radial cross-sectional plane. By selecting the outline shape, the elasticity of the radial sealing ring in the radial direction can be selectively influenced.

A further embodiment of the ring filter insert according to the invention provides that the pockets are formed by blind holes open on one side. In this case, the open side of the pockets preferably lies on the side of the radial sealing ring facing away from the remaining end disk. In this way, the pockets remain open in the plugged state of the ring filter insert to the outside. This advantageously allows the dissipation of frictional heat, the dynamic load of the ring filter insert occurs, for example as a result of vibrations of the associated internal combustion engine and a motor vehicle equipped therewith. Damage to the radial seal due to overheating is avoided.

Preferably, it is further provided that the pockets forming blind holes have an axial length which is between 30 and 90%, preferably between 40 and 80%, the axial length of the radial seal. It will be achieved on the one hand, the desired high elasticity in conjunction with a high restoring force and on the other the desired heat dissipation. By varying the axial length of the blind holes, the properties of the sealing ring can be optimized with regard to its various properties for the individual application.

Alternatively, the pockets may be formed by axially open on both sides, through holes. This design is particularly suitable for separately manufactured radial seals, since it does not depend on a particular installation position, so that assembly errors are excluded in this way.

In one embodiment, the blind holes or through holes forming the pockets have, apart from a draft angle, a cross-section that is essentially constant over their axial length. This gives the sealing ring over the axial length of the holes substantially constant elastic properties.

Alternatively, there is the possibility that the blind holes or through holes forming the pockets have, viewed in their axial direction, a conicity which extends beyond a draft angle, wherein a cross section of the blind holes or through holes in their axial becomes larger towards the outside. In this embodiment, the elasticity of the sealing ring varies in its axial direction, wherein the elasticity at the axially outer end of the sealing ring is greater and then decreases towards the filter material body of the filter insert. This distribution of elasticity facilitates the attachment of the sealing ring on the connection piece at the beginning of Aufsteckens and at the same time ensures in a Aufsteckendlage for a tight fit of the sealing ring on the connection piece.

In this case, the blind holes or through holes forming the pockets preferably have a cone angle of 3 to 8 °, preferably 5 °, since such cone angles are well suited for the desired purpose.

Finally, according to the invention, it is also provided that the radial sealing ring has an inlet slope at its front region in the direction of attachment of its radially inner side. This inlet bevel facilitates the attachment of the ring filter insert to the associated connecting piece and avoids damage to the sealing contour or the sealing contours of the radial sealing ring. Suitably, the connecting piece of the associated filter has an inlet slope, which supports the function of the inlet slope on the radial sealing ring.

In the following, embodiments of the invention will be explained with reference to a drawing. The figures in the drawing show:

1 shows a ring filter insert in a perspective view obliquely from above on its upper part, 2 shows the ring filter insert from FIG. 1 in an enlarged partial view and in longitudinal section, with the sectional plane in a first radial direction, FIG.

3 shows the ring filter insert in the same representation as in FIG. 2, now in a second sectional plane offset in the circumferential direction, FIG.

FIG. 4 shows the ring filter insert in the same representation as in FIG. 3 in a modified embodiment,

FIG. 5 shows the ring filter insert from FIG. 1 in a perspective partial view and in longitudinal section, together with an associated connecting piece immediately before joining to it,

FIG. 6 shows, in the same representation as in FIG. 5, the annular filter insert and the connecting piece in an interconnected state,

7 shows a section of a radial sealing ring, which forms part of the annular filter insert according to FIGS. 1 to 5, as a separate individual part in a perspective view and in section, FIG.

FIG. 8 shows the radial sealing ring in the same representation as in FIG. 7 in a modified embodiment,

9 shows the ring filter insert in the same representation as in FIG. 3 in a further, fourth embodiment, FIG. FIG. 10 shows the ring filter insert in the same representation as in FIG. 9 in a fifth embodiment,

11 shows the ring filter insert in the same representation as in Figure 9 in a sixth embodiment, and

12 shows the ring filter insert in the same representation as in Figure 9 in a seventh embodiment.

Figure 1 shows in a perspective view obliquely from above the upper part of a ring filter insert 1, which consists of a filter material body 10, which is enclosed on the upper side and, which is not visible here, also on the underside of each end plate 11. The filter material body 10 consists for example of a hollow cylindrical body of a zigzag folded filter material web, as is known per se. At its end faces of the filter cloth body 10 is sealingly connected to the end plates 11, for example glued or welded.

The visible in Figure 1 face plate 11 has in its center a connection opening 13, which serves to connect the ring filter insert 1 with a matching connecting piece of a filter, which is not shown here. Inside the Filterstoffkörpers 10 is a support dome 18, which is formed here lattice-shaped and which supports the filter cloth body 10 during operation of the filter against radially from outside to inside acting forces. The end plate 11 is formed in the embodiment shown with a one-piece collar 14 which projects beyond the top of the end plate 11 in the axial direction. Radially inside a radial sealing ring 20 is arranged in the collar 14, which serves for sealing between the annular filter insert 1 and the associated connection piece.

The radial sealing ring 20 is a molded body which consists of an elastomer, and has in its interior hollow pockets 21, whose longitudinal axes in the axial direction of the annular filter insert 1 and parallel to each other. The hollow pockets 21 are distributed at a small distance from each other over the circumference of the radial seal 21. In addition, here are the pockets 21 upwards, that is, to the side facing away from the filter material body 10 side of the ring filter insert 1, open.

Figure 2 shows an enlarged view of a section of the ring filter insert 1 according to Figure 1, now in a longitudinal section. At the bottom in FIG. 2, a small part of the filter material body 10 can be seen with the support dome 18 arranged radially inside. The upper end side of the filter cloth body 10 in FIG. 2 is covered with the end disk 11. Particularly clear in Figure 2, the one-piece design of the collar 14 with the remaining end plate 11th

The collar 14 forms a radial support surface 15 and an axial support surface 16, wherein these two support surfaces 15, 16 support the radial seal 20 at its outer periphery 25 and at its axially lower side 26.

The radial sealing ring 20 has in its interior the hollow pockets 21 which extend to the axially upper side 22 of the radial sealing ring 20 are open towards. Between the mutually adjacent hollow pockets 21 each material bridges 27 remain whose material thickness substantially corresponds to the material thickness between the pockets 21 and the outer periphery 25 of the radial seal 20. Thus, accumulations of material in the region of the radial sealing ring 20 are avoided, whereby at the same time disturbing sink marks are avoided and a low material consumption for the radial sealing ring 20 is achieved.

At its radially inner side 23, the radial sealing ring 20 has a wavy contour with two wave crests seen in the axial direction. Each wave crest forms a sealing zone 24, with which the radial sealing ring 20 here has two sealing zones 24 which run parallel to each other at an axial distance. At its top in Figure 2, the filter cloth body 10 furthest away region of its radially inner side 23 of the radial seal 20 has an inlet slope 28, which facilitates the attachment of the ring filter insert 1 on an associated, not shown in Figure 2 connecting piece.

The radial sealing ring 20 can be injection-molded onto the end disk 11, more precisely its collar 14, or produced simultaneously with the end disk 11 in a two-component injection-molding process. Alternatively, the radial seal 20 can also be made as a separate item and then with the collar 14 of the end plate 11 releasably or permanently, for example by gluing or welding, are connected.

Radially inside has the end plate 11 at its collar 14 axially below the radial sealing ring 20 a plug-in stop 17 in the form of a step. This attachment stop 17 forms a stop surface for the with Ring filter element 1 cooperating connection piece, as will be shown later with reference to FIG 6.

In the center of the end disk 11, which is only partially shown here, is the central connection opening 13, which is surrounded concentrically by the collar 14 and the radial sealing ring 20.

FIG. 3 shows in the same representation as FIG. 2 the ring filter insert 1, wherein now the cutting plane is slightly twisted in the circumferential direction, so that now the cutting plane runs exactly through one of the hollow pockets 21. At the cut pocket 21 it is clear that the pockets 21 are here each formed as a blind hole, so are only open towards the top, but not down. Between the adjacent pockets 21 are each the material bridges 27th

On the radially inner side 23 of the radial sealing ring 20 are the two sealing zones 24, which cooperate with the connecting piece, not shown in Figure 3. The radial sealing ring 20 and this radially outwardly supporting collar 14 surround the central connection opening 13 of the end plate 11. Below the end plate 11 is still a small part of the filter material body 10 and this radially inside supporting support dome 18 can be seen.

FIG. 4 shows, in the same representation as FIGS. 2 and 3, the ring filter insert 1 in a modified embodiment. The change consists in that, in the example according to FIG. 4, the individual pockets 21 have a round outline in cross section, whereas in the example according to FIG. 2 and FIG. have substantial rectangular cross-section with slightly rounded corners.

Also in the radial sealing ring 20 according to Figure 4, the pockets 21 are formed as blind holes, wherein material bridges 27 are again between adjacent pockets 21. At the axially upper side 22 of the radial sealing ring 20, the pockets 21 are open, while they are closed to the axially lower side 26 of the radial sealing ring 20 out. The axial length of the pockets 21 forming blind holes here is about 70% of the axial length of the sealing ring. 2

The end plate 11 also covers the end face of the filter material body 10, which is supported radially inwardly by the support dome 18.

In the center of the end disk 11, the central connection opening 13, which is surrounded by the collar 14 and the radially inwardly disposed radial sealing ring 20, also lies here. Below the radial sealing ring 20, the collar 14 has the attachment stop 17 in the form of the inward-jumping step. On its radially inner side 23 of the radial seal 20 is formed with the previously described wavy contour with the two parallel to each other in axial distance sealing zones 24. At its upper, inner region, the radial sealing ring 20 here also has the inlet bevel 28.

Figure 5 shows a ring filter insert 1 in a partial view in longitudinal section, together with a portion of an associated connecting piece 30, which is also shown in partial view and in longitudinal section, immediately prior to joining together. The connecting piece 30 is formed by a pipe section whose outer periphery 32 has a diameter which is slightly larger than the smallest inner diameter of the radial sealing ring 20 in its relaxed state, as shown in FIG. Near its lower front end of the connecting piece 30 has at its outer periphery 32 an inlet slope 38, which cooperates with the inlet bevel 28 radially inwardly on the radial seal 20 and the mating of the ring filter insert 1 and connecting piece 30 facilitates.

With regard to the further details shown in Figure 5 of the ring filter insert 1, reference is made to the preceding description.

FIG. 6 shows the ring filter insert 1 and the connecting piece 30 in the same representation as in FIG. 5, but now in their interconnected state, in which the ring filter insert 1 with its end plate 11 and the connection opening 13 provided therein is plugged onto the connecting piece 20 in the axial direction.

In this mated condition, the connecting piece 30 protrudes into the connection opening 13 of the annular filter insert 1, wherein now the connecting piece 30 rests with its in Fig. 6 downwardly facing end edge on the attachment stop 17 of the end plate 11. This defines a defined degree of insertion depth.

Since, as explained with reference to Figure 5, the outer diameter of the outer circumference 32 of the connecting piece 30 is slightly larger than the smallest inner diameter of the radial sealing ring 20 in its relaxed state, in the mated state, as shown in FIG 6, the radially inner side 23 of Radial sealing ring 20 through the Outer periphery 32 of the connecting piece 30 is pressed radially outward. As a result, the radial seal 20 is compressed, since it can not escape radially outward due to the collar 14 and the radial support surface 15 formed by this radially outward. Thus, now the radial seal 20 with its radially inner side 23 is sufficiently strong and thus safe sealing on the outer periphery 32 of the connecting piece 30 at. By not shown in the drawing locking the ring filter element 1 can be secured in its plugged onto the connecting piece 30 position to prevent unwanted automatic slipping of the ring filter insert 1 of the connecting piece 30 safely.

In the assembled state of ring filter insert 1 and connecting piece 30, the central connection opening 13 in the end disk 11 is aligned with the hollow interior of the connecting piece 30, so that a flow path for a filtered medium from the interior of the filter material body 10 through the connection opening 13 is formed in the connecting piece 30 ,

In many applications, the ring filter insert 1 is subject to dynamic external influences, in particular vibrations caused, for example, by an internal combustion engine to which the ring filter insert 1 belongs. These vibrations can lead to frictional heat in the region of the radial sealing ring 20, which can be dissipated here by the pockets 21 provided therein over a large area and thus effectively to the environment. Overheating and damage to the radial sealing ring 20 caused thereby is thus avoided. FIG. 7 shows, in a perspective, cutaway view, a detail of a radial sealing ring 20 manufactured as a separate individual part, which in its shape corresponds to the radial sealing ring 20 according to FIGS. 1 and 2. Distributed over the circumference are in the radial seal

20 formed again a large number of hollow pockets 21, whose longitudinal axes parallel to each other and parallel to the axial direction of the radial seal 20. Again, the pockets 21 are formed as blind holes, which are open to the axially upper side 22 of the radial seal 20 and closed to the axially lower side 26 of the radial seal 20. The pockets 21 extend approximately over the upper two-thirds of the axial height of the radial sealing ring 20. By varying the depth of the pockets

21 relative to the axial height of the radial sealing ring 20 whose elasticity properties can be adjusted in the desired manner. In extreme cases, the pockets 21 can also be designed as continuous, both upwardly and downwardly open holes. It is also possible to form the pockets 21 as non-slip holes originating from the axial top side 22 and from the axial bottom side 26.

On the radially inner side 23 of the radial seal 20 are the two axially parallel spaced sealing zones 24. Radially outward is the smooth running outer circumference 25 of the radial seal 20, with which the radial seal 20 in the assembled state to that shown in the preceding figures and described collar 14 and its radial support surface 15 is supported. The axially lower side 26 of the radial sealing ring 20 is also formed substantially smooth surface, so that they can create a flat surface to the previously described axiale support surface 16 of the collar 14 of the end plate 11. The radial seal shown in Figure 7 can be connected after its production as a separate item either releasably or permanently, for example by gluing or welding, with an associated end plate 11.

In the example according to FIG. 7, the pockets 21 are designed with a substantially rectangular outline in cross-section, the corners being slightly rounded.

As an alternative embodiment, FIG. 8 shows an example of the radial sealing ring 20, in which the hollow pockets 21 have a round outline in cross-section. Otherwise, the radial seal 20 made as a single part according to FIG. 8 corresponds to the exemplary embodiment according to FIG. 7. With regard to the further reference numbers in FIG. 8, reference is made to the preceding description.

A further embodiment of the radial sealing ring 20 is shown in FIG. 9 in a section in a representation corresponding to FIG. Characteristic of the embodiment of the radial sealing ring 20 according to FIG. 9 is that a radially outer surface of the pockets 21 is formed with a surface contour 29 that is corrugated in the axial direction. In the region of the corrugated surface contour 29, a thickening of the material of the radially outer part of the radial sealing ring 20 is generated approximately at half the axial length of the pockets 21. The opposite, radially inner side of the hollow pockets 21 is designed here in a straight line. The corrugated surface contour 29 ensures in a plugged on the connection piece according to Figure 6 state for a reinforced press fit of the filter insert. 1 Since the radial seal 20 is made of an elastomeric material, a demolding of the hollow pockets 21 in the axial direction can be done easily, even if the pockets 21 have an undercut in the cross section according to FIG. The material of the radial sealing ring 20 can deform elastically in the demolding process, in which the radial sealing ring 20 is separated from an associated injection molding tool, such that a part of the mold lying in the lower, widened region of the pockets 21 is formed by the height of the corrugated surface contour 29 Constriction can be moved through without the sealing ring 20 takes damage.

In its remaining parts, the ring filter insert 1 according to FIG. 9 corresponds to the exemplary embodiments described above.

FIG. 10 shows, in the same representation as FIG. 9, a further embodiment of the radial sealing ring 20. It is characteristic of the radial sealing ring 20 according to FIG. 10 that here a radially inner side of the hollow pockets 21 is formed with a corrugated surface contour 29 '. The opposite, radially outer side of the hollow pockets 21 is executed here in a straight line. With this embodiment of the radial sealing ring 20, the same advantages and effects are achieved as with the radial sealing ring according to FIG. 9. In the other parts, the annular filter insert 1 according to FIG. 10 corresponds to the examples described above.

Figure 11 shows an embodiment of the radial seal 20, which has a high degree of similarity with the example of Figure 4. The difference between the radial sealing rings 20 according to FIGS. 4 and 11 is that in the example of Figure 4, the axial length of the hollow pockets 21 is about 70% of the axial length of the radial seal 20, while in the example of Figure 11, the axial length of the hollow pockets 21 only about 40% of the axial length of Radial seal 20 is.

In the embodiment according to FIG. 11, because of the hollow pockets 21 which are shorter in comparison with FIG. 4, the radial sealing ring 20 has less elasticity and therefore higher strength in its axially lower part, which does not ensure the tight fit of the radial ring 20 in FIG reinforced connecting piece shown. At the beginning of the Aufsteckens the Aufsteckvorgang but is relieved because in its axially upper portion of the radial seal 20 due to the hollow pockets 21 there has a greater elasticity and thus flexibility. In addition, here the start of Aufsetzens is supported by the also in the upper axial region of the radial seal 20 radially inwardly integrally formed inlet bevel 28.

Finally, FIG. 12 shows, as the last exemplary embodiment, a radial sealing ring 20, for which it is characteristic that the hollow pockets 21 have a conicity extending beyond a demoulding slope. In this case, the cross section of the pockets 21 becomes larger in the axial direction to the outside. The angle α of the conicity of the pockets 21 in the example according to FIG. 12 is approximately 5 °.

This ensures that the elasticity of the radial sealing ring 20 is a function of its axial length, wherein the elasticity of the radial sealing ring 20 at the axially uppermost end is greatest and from there in the direction of the filter material body 10 towards less. Also with this embodiment of the radial sealing ring 20, a simplified attachment of the ring filter insert 1 with the radial sealing ring 20 is achieved on an associated connecting piece at the same time fixed end seat of the radial sealing ring 20 on the connecting piece.

Claims

Claims:

1. ring filter insert (1) for a filter for filtering a fluid medium, in particular air or oil or fuel for an internal combustion engine, wherein the ring filter insert (1) comprises two end disks (11) and a filter material body arranged between them (10), wherein at least one the end disks (11) has a connection opening (13) with which the ring filter insert (1) can be plugged onto a connecting piece (30) of the filter, and at least one elastically flexible radial sealing ring (20) is connected between the connection opening (13) and the connecting piece (30) ) is provided from plastic, characterized in that the radial sealing ring (20) is an annular body made of an elastomer having arranged in its interior hollow pockets (21).

Second ring filter insert according to claim 1, characterized in that the pockets (21) in the axial direction of the annular filter insert (1) parallel to each other and in the circumferential direction of the radial sealing ring (20) are arranged at a distance from each other.

3. ring filter insert according to claim 1 or 2, characterized in that the pockets (21) on its radially inner side and / or on its radially outer Side have an axially corrugated surface contour (29, 29 ').

4. ring filter insert according to claim 3, characterized in that the corrugated surface contour (29, 29 ') is formed by a on the radially inner side or on the radially outer side of the pockets (21) integrally formed wave crest and that the other side of the pockets (21) is formed in a straight line in the axial direction.

5. ring filter insert according to claim 3 or 4, characterized in that the corrugated surface contour (29, 29 ') of the pockets (21) seen in the circumferential direction of the radial sealing ring (20) is formed continuously.

6. ring filter insert according to claim 3 or 4, characterized in that the corrugated surface contour (29, 29 ') of the pockets (21) in the circumferential direction of the radial sealing ring (20) is formed interrupted.

7. ring filter insert according to one of claims 1 to 6, characterized in that the radial sealing ring (20) on its radially inwardly facing, with the connecting piece (30) cooperating side (23) has a surface contour with a plurality of axially spaced apart, circumferential sealing zones (24 ) Has.

8. ring filter insert according to claim 7, characterized in that the surface contour on the radially inner side (23) of the radial sealing ring (20) seen in the axial direction wavy with at least two radially inwardly facing wave crests, each forming a sealing zone (24) is.

9. ring filter insert according to one of claims 1 to 8, characterized in that the radial sealing ring (20) on its outer circumference (25) has an abutment contour with which the radial sealing ring (20) in an assembled state to a radially outwardly surrounding support surface (15) the associated end plate 11 is applied.

10. ring filter insert according to claim 9, characterized in that the radial sealing ring (20) on its axially to the filter material body (10) facing side (26) has a contact contour with which the radial seal (20) in an assembled state on a support surface axially supporting him (16) of the associated end plate (11) rests.

11. ring filter insert according to one of claims 1 to 10, characterized in that the radial sealing ring (20) is injection-molded onto the associated end plate (11).

12. ring filter insert according to one of claims 1 to 10, characterized in that the radial seal (20) having end plate (11) consists of a plastic and that the end plate (11) and the radial sealing ring (20) made in a two-component injection molding together and characterized connected to each other.

13. ring filter insert according to one of claims 1 to 10, characterized in that the radial sealing ring (20) is a separately manufactured injection molded part.

14. ring filter insert according to claim 13, characterized in that the separately manufactured radial seal (20) with the associated end plate (11) is detachably connected.

15. ring filter insert according to claim 14, characterized in that the radial seal (20) having end plate (11) has a radially inwardly open sealing ring receptacle, in which the separately manufactured radial seal (20) under fixing both in the axial direction and in the radial direction outside is inserted.

16. ring filter insert according to claim 13, characterized in that the separately manufactured radial seal (20) with the associated end plate (11) fixedly connected, in particular glued or welded, is.

17. ring filter insert according to one of claims 2 to 16, characterized in that a first material thickness of the radial sealing ring (20) between its pockets (21) and its outer periphery (25) and a second material thickness of the radial sealing ring (20) in the region of material bridges (27 ) are equal between two circumferentially adjacent pockets (21).

18 ring filter insert according to one of claims 2 to 17, characterized in that the pockets (21) seen in a radial cross-sectional plane have a polygonal, in particular hexagonal or rectangular or square, outline or a round or oval or elliptical outline.

19. ring filter insert according to one of claims 2 to 18, characterized in that the pockets (21) are formed by blind holes axially open on one side.

20. ring filter insert according to claim 19, characterized in that the pockets (21) forming blind holes have an axial length which is between 30 and 90%, preferably between 40 and 80%, the axial length of the radial sealing ring (20).

21. ring filter insert according to one of claims 2 to 18, characterized in that the pockets (21) are formed by axially open on both sides, through holes.

22 ring filter insert according to one of claims 19 to 21, characterized in that the pockets (21) forming blind holes or through holes, apart from a Entformungsschräge, over its axial length substantially constant cross-section.

23. ring filter insert according to one of claims 19 to 21, characterized in that the pockets (21) forming blind holes or through holes seen in their axial direction have a demformungsschräge beyond tapering conical, wherein a cross section of the blind holes or through holes in the Axial direction becomes larger towards the outside.

24. ring filter insert according to claim 23, characterized in that the pockets (21) forming bag holes or through holes have a cone angle α of 3 to 8 °, preferably of 5 °.

25. ring filter insert according to one of claims 1 to 24, characterized in that the radial sealing ring (20) has an inlet slope (28) at its front in the attachment direction of its radially inner side.