Filter apparatus, vehicle, use and method

Abstract

Filter apparatus (6) in particular passenger compartment filter apparatus, for example for a motor vehicle (1), comprising a filter element (8) having a filter medium body (9) and a frame (10) surrounding the filter medium body (9), wherein the frame (10) features opposite lateral surfaces (11, 12), a plurality of engagement elements (22a to 22d), and a filter housing (7) featuring, on two opposing wall sections (24, 25), in each case two engagement counter elements (28a to 28d) in which in each case one of the plurality of engagement elements (22a to 22d) can be accommodated in a positive fitting manner, wherein the engagement counter elements (28a to 28d) in each case are designed as a groove in the respective wall section (24, 25) of the filter housing (7) and feature: an insertion section (31) which, when the filter element (8) is mounted in the filter housing (7), permits an insertion movement of the respective engagement element (22a to 22d) substantially along the throughflow direction (L), and a locking section (32) connected to the insertion section (31) and angled with respect to the insertion section (31), wherein a respective engagement element (22a to 22d) is disposed on a respective lateral surface (11, 12) of the filter element (8) when the filter element (8) is mounted in the filter housing (7), extends away from the filter medium body (9), and is held in a respective locking section (32).

Claims

1. Filter apparatus (6), in particular passenger compartment filter apparatus, for example for a motor vehicle (1), comprising: a filter element (8) having a filter medium body (9) and a frame (10) surrounding the filter medium body (9), wherein the frame (10) features opposing lateral surfaces (11, 12), a plurality of engagement elements (22a to 22d), and a filter housing (7) which features, on two opposing wall sections (24, 25), in each case two engagement counter elements (28a to 28d) in which in each case one of the plurality of engagement elements (22a to 22d) can be accommodated in a positive fitting manner, wherein the engagement counter elements (28a to 28d) in each case are designed as a groove in the respective wall section (24, 25) of the filter housing (7) and featuring: an insertion section (31) which, when the filter element (8) is mounted in the filter housing (7), permits an insertion movement of the respective engagement element (22a to 22d) substantially along the throughflow direction (L), and a locking section (32) connected to the insertion section (31) and angled with respect to the insertion section (31), wherein a respective engagement element (22a to 22d) is disposed on a respective lateral surface (11, 12) of the filter element (8) when the filter element (8) is mounted in the filter housing (7), extends away from the filter medium body (9), and is held on a respective locking section (32), and wherein the filter medium body (9) features a single- or multi-layer filter medium comprising a filter fleece, which features synthetic fibers.

2. Filter apparatus according to claim 1, wherein the two engagement counter elements (28a to 28d) are designed in opposite directions and/or feature each an L-shaped geometry, wherein the L-shaped geometries are preferably arranged mirror-symmetrically (35) to one another and/or wherein one leg of the L-shape corresponds to the insertion section (31) and the other leg of the L-shape corresponds to the locking section (32), and/or wherein the two locking sections (32) of the two engagement counter elements (28a to 28d) face away from one another and the two insertion sections (31) are disposed parallel to one another and/or wherein, in an undeformed state of the filter element (8), a distance (d) between the engagement elements (22a to 22d) is greater than a distance (D) between the two insertion sections (31) of a wall section (24, 25) of the filter housing (7), so that preferably the engagement elements (22a to 22d) snap into the locking sections (32) at the end of the insertion movement, and/or wherein one or a plurality of the engagement elements (22a to 22d) are designed as separate parts and/or are designed to be detachably attachable to the filter element (8) and/or the filter housing (7).

3. Filter apparatus according to claim 1 or 2, wherein one or the plurality of engagement elements (22a to 22d) are attached to the filter element (8), in particular glued or welded thereto, or formed integrally therewith.

4. Filter apparatus according to one of the preceding claims, wherein the respective locking section (32) features a pocket or through opening (34) in the wall section (24, 25), into which the respective engagement element (22a to 22d) engages in a positive fitting manner in the assembled state, in particular is snapped in.

5. Filter apparatus according to one of the preceding claims, wherein the lateral surfaces (11, 12) of the frame (10) of the filter element (8) each feature two through openings (36) which, in the assembled state of the filter element (8) in the filter housing (7), lie opposite a respective locking section (32), wherein, in the assembled state, a respective engagement element (22a to 22d) further engages through one of the two through openings (36) and positively engages in the respective locking section (32).

6. Filter apparatus according to one of the preceding claims, featuring holding sections (29a to 29d) connected to a respective engagement element (28a to 28d) and disposed in a recessed area (30) of the filter medium body (9) in the assembled state, wherein the recessed area (30) of the filter medium body (9) is accessible from the side (RO) from which the mounting of the filter element (8) in the filter housing (7) is performed.

7. Filter apparatus according to one of the preceding claims, further featuring holding sections (29a to 29d) which are connected to a respective engagement element (22a to 22d) and, in the assembled state, engage at least partially around or behind the filter element (8), wherein the holding sections (29a to 29d) engage around or behind the filter element (8), in particular on its inflow and/or outflow side (RO, RE) and/or on an upstream and/or downstream edge (42) of the frame (10).

8. Filter apparatus according to claim 7, wherein the respective holding sections (29a to 29d) feature a cross shape and the respective engagement element (22a to 22d) is disposed at the lower end (41a) of the cross shape, wherein the cross shape preferably laterally (41c, 41d) engages the filter element (8), in particular on the upstream and/or downstream edge (42) of the frame (10), and/or the wall sections (24, 25) of the filter housing (7), and/or wherein an upper end (41b) of the cross shape features a gripping section for manually mounting the engagement element (41b) on the filter element (8) and/or the filter housing (7).

9. Filter apparatus according to one of the preceding claims, wherein each two of the plurality of engagement elements (22a to 22d) or two of the holding sections (29a to 29d) are connected using a connector (38).

10. Filter apparatus according to claim 9, wherein the connector (38) extends parallel or perpendicular to the lateral surfaces (11, 12) of the frame (10) in the assembled state.

11. Filter apparatus according to claim 9 or 10, wherein two of the plurality of engagement elements (22a to 22d) each disposed on opposing lateral surfaces (11, 12) of the frame (10) or on the same lateral surface (11, 12) of the frame (10) are connected to each other using the connector (8).

12. Filter apparatus according to one of the claims 9 to 11, wherein the connector (38) is elastically deformable for inserting the engagement elements (22a to 22d) into the respective locking section (32).

13. Filter apparatus according to one of the claims 9 to 12, wherein the connector (38) extends across fold tips (16) of the filter medium body (9) and/or in a recessed area (30) through the filter medium body (9).

14. Vehicle (1) having a filter apparatus (6) according to one of the preceding claims.

15. Use of a set (40) comprising a filter element (9) and a plurality of engagement elements (22a to 22d) in a filter apparatus (6) according to one of the preceding claims, wherein the filter element (8) comprises a filter medium body (9) and a frame (10) surrounding the filter medium body (9), wherein the frame (10) features opposing lateral surfaces (11, 12), wherein a respective engagement element (22a to 22d) is adapted to be disposed on a respective lateral surface (11, 12) of the filter element (8) in an assembled state of the filter element (8) in the filter housing (7), to extend away from the filter medium body (9) and to be positively held in a respective locking section (32) of the filter housing (7).

16. Use according to claim 15, wherein a respective engagement element (22a to 22d) is adapted to be inserted along a respective insertion section (31) of the filter housing (7) substantially along the throughflow direction (L) when mounting the filter element (8) in the filter housing (7).

17. Method for mounting a filter element (8) in a filter housing (7) using a plurality of engagement elements (22a to 22d), wherein the filter element (8) comprises a filter medium body (9) and a frame (10) surrounding the filter medium body (9), wherein the frame (10) features opposite lateral surfaces (11, 12), wherein the filter housing (7) features, on two opposing wall sections (24, 25), in each case two engagement counter elements (28a to 28d) in which in each case one of the plurality of engagement elements (22a to 22d) can be accommodated in a positive fitting manner, wherein the engagement counter elements (28a to 28d) in each case are designed as a groove in the respective wall section (24, 25) of the filter housing (7) and feature: an insertion section (31) which, when the filter element (8) is mounted in the filter housing (7), permits an insertion movement of the respective engagement element (22a to 22d) substantially along the throughflow direction (L), and a locking section (32) connected to the insertion section (31) and angled with respect to the insertion section (31), wherein the method features: a) inserting (S1) the filter element (8) into the filter housing (7), and b) arranging (S2) a respective engagement element (22a to 22d) on a respective lateral surface (11, 12) of the filter element (8) such that it extends away from the filter medium body (9) and is positively held in a respective locking section (32).

18. Method according to claim 17, wherein, before executing step b), the respective engagement element (22a to 22d) is inserted (S3) along a respective insertion section (31) of the filter housing (7) substantially along the throughflow direction (L).

Description

DESCRIPTION OF DRAWINGS

[0072] Shown is in:

[0073] FIG. 1: a schematic diagram of a motor vehicle with a filter apparatus;

[0074] FIG. 2: a perspective representation of the filter apparatus of FIG. 1 comprising a filter housing with a passenger compartment filter received therein;

[0075] FIG. 3: a perspective representation of the passenger compartment filter of FIG. 2 comprising a frame and a filter medium;

[0076] FIG. 4: a perspective representation of the filter medium from FIG. 3;

[0077] FIG. 5A: in a perspective view of a filter apparatus according to a first embodiment;

[0078] FIG. 5B: a section I-I from FIG. 5A;

[0079] FIG. 5C: a section II-II from FIG. 5A;

[0080] FIG. 6: an exploded view of the filter apparatus according to FIGS. 5A to 5C;

[0081] FIG. 7A: in a perspective view a filter apparatus according to a second embodiment;

[0082] FIG. 7B: a section I-I from FIG. 7A;

[0083] FIG. 7C: a section II-II from FIG. 7A;

[0084] FIG. 8: an exploded view of the filter apparatus according to FIGS. 7A to 7C;

[0085] FIG. 9A: in a perspective view a filter apparatus according to a third embodiment;

[0086] FIG. 9B: a section I-I from FIG. 9A;

[0087] FIG. 9C: a section II-II from FIG. 9A;

[0088] FIG. 10: in an exploded view the filter apparatus according to FIGS. 9A to 9C;

[0089] FIG. 11 to FIG. 15: different embodiments of filter elements together with associated engagement elements, and

[0090] FIG. 16: a method according to one embodiment.

[0091] In the figures, the same reference numerals denote identical or analog components, unless otherwise stated.

MODE(S) FOR INVENTION

[0092] FIG. 1 shows a motor vehicle 1 with an air-conditioning system 2, which may be designed as a heating air conditioning system. The air-conditioning system 2 takes in outdoor air 3 and supplies filtered air 4 to a passenger compartment 5 of the motor vehicle 1. For this purpose, the air-conditioning system 2 comprises a filter apparatus 6 shown in FIG. 2.

[0093] The filter apparatus 6 comprises a filter housing 7 with a passenger compartment filter 8 (also referred to herein as “filter element”) accommodated therein, in particular in a replaceable manner. The passenger compartment filter 8 is shown in more detail in FIG. 3. The passenger compartment filter 8 has a filter medium 9 (also referred to herein as “filter medium body”), which is connected in particular all around to a frame 10 (FIG. 3). The frame 10 may comprise, for example, sidebands 11, 12 and headbands 13, 14.

[0094] The filter medium 9 is shown isolated in FIG. 4. The filter medium 9 is, for example, a filter fleece, filter fabric, filter scrim or filter felt, in particular a needle felt. In particular, the filter medium 9 may be produced by a meltblown process. The filter medium 9 may feature natural fibers, such as cotton, or synthetic fibers, for example made of polyester, polyphenyl sulfide or polytetrafluoroethylene. During processing, the fibers can be oriented in, obliquely and/or transversely to the machine direction M. Also, the fibers may be stretched in a spatial direction. The filter medium 9 may be designed in a single layer or in multiple layers.

[0095] The filter medium 9 may feature folds 15, which typically extend transverse to the machine direction M. The folded filter medium 9 is also referred to as pleats. The folds 15 may be created by folding along sharp fold edges 16 (also referred to as “fold tips”), or by a corrugated design of the filter medium 9. A respective fold 15 may be defined by two fold sections 15a, which are connected to one another by a corresponding fold edge 16. According to the embodiment example, the fold edges 16 point in or against the inflow direction or throughflow direction, which is indicated by the arrow L in FIG. 2. The folding can in particular be designed as a zig-zag folding.

[0096] A folding in which the folds 15 feature a varying height H is also possible. Furthermore, the fold distance between the folds 15 may vary so that the distance A1 is not equal to the distance A2. The filter medium 9 may be self-supporting, i.e. the folds 15 are dimensionally stable when flowing through them as intended during filter operation.

[0097] In machine direction M, the filter medium 9 is limited by end folds 17, 18. Transversely thereto, the filter medium 9 is limited by fold front edges 19, 20 (also referred to as folding profiles). By “fold front edge” is meant the end face side of the fold surface which extends between adjacent fold edges 16 of a respective fold 15.

[0098] The filter medium 9 may feature a rectangular shape in top view, i.e. in the plane E of its planar extension. However, a triangular, pentagonal or polygonal, round or oval shape is also conceivable.

[0099] The sidebands 11, 12 shown in FIG. 3 are connected to the fold front edges 19, 20, and the headbands 13, 14 are connected to the end folds 17, 18, in particular by fusing, welding or gluing. The sidebands 11, 12 as well as the headbands 13, 14 may form the frame 10 in one piece or in several pieces. The sidebands 11, 12 as well as the headbands 13, 14 can, for example, be made of an in particular flexible fiber material or as in particular rigid plastic injection molded components. In particular, the frame 10 may be produced by injection molding onto the filter medium 9.

[0100] The filter medium 9 may act as a particulate filter, filtering particles, in particular dust, airborne particulates or liquid droplets, from the intake air 3. In addition, the filter medium 9 may act as an odor filter. For this purpose, it may for example feature a layer of activated carbon. The filter medium 9 may be adapted in general to absorb or adsorb certain solid, liquid and/or gaseous substances.

[0101] During filter operation, air L flows through the filter medium 9 perpendicular to its flat extension, as shown in FIG. 2. The air L flows from a raw side RO of the passenger compartment filter 8 to a clean side RE thereof.

[0102] In order to ensure a sufficient seal between the raw and clean sides RO, RE, a seal may be provided between the passenger compartment filter 9 and the filter housing 7. For example, the seal may be integrated into the frame 10. In this case, the frame 10 is at least partially formed of a sealing material. As an alternative, the seal may be provided as an additional part, for example attached to the frame 10, in particular injection-molded thereon. Such a seal 21 is shown in an exemplary fashion and in detail in FIG. 3.

[0103] FIG. 5A shows in a perspective view a filter apparatus 6 according to a first embodiment. FIG. 5B shows a section I-I, FIG. 5C shows a section II-II from FIG. 5A. FIG. 6 shows an exploded view of the first embodiment. In the following, reference is made collectively to FIGS. 5A to 6.

[0104] The filter apparatus 6 comprises a filter housing 7 (FIG. 5A) with a filter element 8 received therein. The filter element 8 is held in the mounting position shown using a plurality of engagement elements 22a to 22d (FIG. 6).

[0105] A filter medium or filter medium body is designated in the figures by 9. It is enclosed by a circumferential frame 10. It is composed of sidebands 11, 12 (also referred to as “lateral surfaces”) and headbands 13, 14.

[0106] For example, the filter housing 7 also comprises a frame 23 which is composed, for example, of respective opposing wall sections 24, 25 (FIG. 6) and 26, 27. In this case, the wall sections 24, 25 are opposite the sidebands 11, 12, and the wall sections 26, 27 are opposite the headbands 13, 14. The filter housing 7 may also feature a different shape.

[0107] According to the embodiment example, the wall sections 24, 25 are each designed with two engagement counter elements 28a to 28d (FIG. 6). One of the engagement elements 22a to 22d can be positively accommodated therein in each case. For example, the engagement counter elements 28a to 28d are each designed as a groove. In this case, the engagement counter elements 28a, 28b are provided in the wall section 24, the engagement counter elements 28c, 28d in the wall section 25. The filter housing 7 together with the engagement counter elements 28a to 28d can, for example, be made of plastic, in particular by injection molding.

[0108] The engagement elements 22a to 22d may be designed as, for example, tenons. In particular, as shown in FIGS. 5A to 6, they may be provided at one end of a holding section 29a to 29d or formed integrally therewith. The holding sections 29a to 29d may be made in the form of tabs. These tabs may provide a grip section for gripping the engagement elements 22a to 22d during assembly of the filter apparatus 6, which is easy to grip with the hand. For example, in the assembled state, the holding sections 29a to 29d could be at least partially (or completely) disposed in recessed areas 30. As can be seen in FIG. 5C, such recessed areas 30 can be formed by forming a fold 15′ of the filter medium body 9 with a lower height H′ than the folds 15 adjacent to both sides of the fold 15′, each formed with a height H.

[0109] The engagement counter elements 28a to 28d may be configured in detail as follows. Each of the engagement counter elements 28a to 28d comprises - as explained below in an exemplary fashion for the engagement counter element 28a (FIG. 6) - an insertion section 31 and a locking section 32. The sections 31, 32 are preferably part of the same continuous groove. The insertion section 31 preferably extends in the throughflow direction L (see FIG. 5C). It leads from an upstream edge 33 of the wall section 24, for example, towards a center thereof. At that point, the insertion section 31 adjoins the locking section 31 at an angle for example of 90°. This results in an L-shape. A through hole 34 may be provided towards the end of the locking section 32. This completely penetrates the material of the wall section 24. Instead, only one pocket could be provided, which is open (accessible) to the inside. The inflow side corresponds to the raw side RO of FIG. 2.

[0110] As can be seen in FIG. 6, the engagement elements 28a, 28b are designed in opposite directions. For example, the locking sections 32 extend in opposite directions. On the other hand, the insertion sections 31 are arranged parallel to each other. In particular, the engagement counter elements 28a, 28b may be designed mirror-symmetrically with respect to a symmetry axis 35. The symmetry axis 35 is aligned in the throughflow direction L and divides the wall section 24 into approximately equal areas F1, F2.

[0111] In the present case, the engagement elements 22a to 22d — together with their holding sections 29a to 29d — are designed as separate parts, i.e. in the non-assembled state (FIG. 6) they are connected neither to the filter housing 7 nor to the filter element 8. Rather, they are releasably connectable to the filter element 8 and the filter housing 9, thereby securing the filter element 8 in its mounting position in the filter housing 7, as explained in more detail below.

[0112] For example, two through holes 36 are formed in each of the sidebands 11, 12. Once the filter element 8 have been inserted into the filter housing 7, the through holes 36 respectively face the through holes 34 in the engagement counter elements 28a, 28b (step S1 of the method shown in FIG. 16).

[0113] In a further step, the engagement elements 22a to 22d are now moved into the recessed areas 30 and from there are pushed from the inside through the through holes 36 into the through holes 34. Accordingly, a respective engagement element 22a to 22d is then arranged on a respective lateral surface 11, 12 and extends away from the filter medium body 9. As a result of the fact that the engagement elements 22a to 22d each engage through both the through-hole 36 and the through-hole 34, a positive engagement is realized between them and the filter housing 7 or the filter element 8 (process step S2 in FIG. 6).

[0114] As an alternative, the engagement elements 22a to 22d can already be positioned in the respective through holes 36 before the filter element 9 is inserted into the filter housing 7. The filter element 8 is then bent — for example manually — about an axis 37. The axis 37 extends, for example, perpendicularly to the lateral surfaces 11, 12. Due to this deformation (not shown), the through holes 36 move closer together (not shown), which in the undeformed state feature a greater distance d from one another than the insertion sections 31. The distance between them is designated by D in FIG. 6. Accordingly, due to the deformation, the engagement elements 22a to 22d can then be inserted into the insertion sections 31 which open into the edge 33. The engagement elements 22a to 22d are then pushed along the respective insertion section 31 in the throughflow direction L — in FIG. 6 downwards — until they reach the respective locking section 32 connected to the insertion sections 31. This corresponds to process step S3 of FIG. 16.

[0115] The filter element 8 is then released allowing it to deform back to its initial state. In doing so, the engagement elements 22a to 22d each move outwardly along the locking sections 32 and finally engage positively in the through holes 34, for which purpose pressure is applied to the engagement elements 22a to 22d from the inside, for example manually.

[0116] Advantageously, the holding sections 29a to 29d are accessible from the assembly side from which the filter element 8 is inserted into the filter housing 7, which in the present case corresponds to the raw side RO, and can be easily moved inwardly manually for disassembly of the filter element 9 so that the engagement elements 22a to 22d disengage from the through holes 32, 36.

[0117] FIG. 7A shows a filter apparatus 6 according to a second embodiment in perspective view. FIG. 7B shows a section I-I, FIG. 7C shows a section II-II from FIG. 7A. FIG. 8 shows an exploded view of the second embodiment. Subsequent explanations refer to FIGS. 7A to 8 to 8 collectively, wherein focus is given to differences from the first embodiment according to FIGS. 5A to 6.

[0118] In the second embodiment, and in contrast to the first embodiment, the holding sections 29a, 29b or 29c, 29d of two respective engagement elements 22a, 22b or 22c, 22d, which are disposed on the same lateral surface 11 or 12, are connected to a respective connector 38. The connector 38 is disposed parallel to the lateral surface 11 in the assembled state, as can be seen in FIG. 7A. It also extends above fold tips or fold edges 16.

[0119] The connector 38 may be elastically designed. This is particularly the case for the assembly variant in which the engagement elements 22a, 22b or 22c, 22d are guided along the insertion sections 31 of the engagement counter elements 28a to 28d, since in this case the distance between the adjacent engagement elements 22a, 22b or 22c, 22d is reduced (cf. the explanations on the distances d and D in connection with FIG. 6 above). As soon as the engagement elements 22a to 22d reach their respective locking section 32 towards the end of the respective insertion section 31, they snap elastically outwards into the end of a respective insertion section 32. The positive engagement thus created is secured by the respective connector 38 due to its elasticity or rigidity.

[0120] FIG. 9A shows a perspective view of a third embodiment of a filter apparatus 6. FIG. 9B shows a section I-I, FIG. 9C shows a section II-II from FIG. 9A. FIG. 10 illustrates an exploded view of the third embodiment. In the following, reference is made to FIGS. 9A to 10 collectively, wherein focus is given to explaining the differences with respect to the foregoing embodiments.

[0121] Unlike the second embodiment according to FIGS. 7A to 8, in the third embodiment according to FIGS. 9A to 10, the engagement elements 22a, 22c and 22b, 22d, which are disposed on different lateral surfaces 11, 12 of the frame 10, are connected to a respective connector 38. The connector 38 is preferably elastic and, where appropriate, additionally bent, so that it secures the engagement elements 22a to 22d in their respective engagement position with the through holes 34. For this purpose, in the assembled state, the connector 38 biases the engagement elements 22a, 22c or 22b, 22d located at its ends outwardly, that is in a direction away from the filter element 8. In this case, the connectors 38 are disposed in a direction perpendicular to the lateral surfaces 11, 12. Furthermore, the connectors 38 may extend partially or completely within the recessed areas 30 (see FIG. 9C).

[0122] FIG. 11 shows on the left side a filter element 8 with engagement elements 22a to 22d in a mounting position. The filter housing 7 is not shown for reasons of clarity. On the right side, the engagement elements 22a to 22d together with connectors 38 are shown isolated. In an enlarged view, a holding section 29a for the engagement element 22a is illustrated in more detail in an exemplary fashion.

[0123] According to the embodiment example, the engagement elements 22a to 22d have the shape of hooks. They are arranged to engage positively in the locking sections 32 of the engagement counter elements 28a to 28d shown, for example, in FIG. 6. This is done by pushing the engagement elements 22a to 22d substantially along the throughflow direction L into a gap (not shown) between the filter element 8 and the wall 24 or 25 (see FIG. 6). In doing so, the lateral surfaces 11, 12 are elastically pressed inwardly and then provide a contact pressure which holds the engagement elements 22a to 22d in engagement with the locking sections 32.

[0124] The holding section 29a (see the enlarged view in FIG. 11) is exemplarily designed in a cross shape and comprises four webs 41a to 41d. In this case, web 41a points downward in FIG. 11. The engagement element 22a is integrally molded to its lower end. The web 41b points vertically upwards. It is shorter than the web 41a and serves, for example, as a grip section for manual gripping when inserting the engagement elements 22a to 22d or when removing them as part of the assembly or disassembly of the filter element 8. The web 41c points laterally and is also shorter than the web 41a, for example. The web 41c engages behind an upper edge 42 of the lateral surface (or sideband) 11 with respect to the engagement element 22a. This prevents the filter element 8 from moving along the throughflow direction L with respect to the filter housing 7. The web 41d is also shorter than the web 41a and engages behind the edge 33 (see FIG. 6) of the filter housing 7. This further improves the fixation of the engagement elements 22a to 22d in the locking sections 32.

[0125] In the embodiment example according to FIG. 11, the webs 41a to 41d are an integral part of the connectors 38. Furthermore, the connectors 38 comprise, for example, a further grip section in the shape of a tab 43.

[0126] In the embodiment example according to FIG. 11, a respective connector 38 connects two holding sections 29a, 29b and 29c, 29d, respectively, and two engagement elements 22a, 22b and 22c, 22d, respectively, which are disposed on the same side of a respective lateral surface 11, 12. Accordingly, the connectors 38 extend parallel to the lateral surfaces 11, 12. Two engagement elements 22a, 22b and 22c, 22d respectively form a separate part with two holding sections 29a, 29b and 29c, 29d respectively and one connector 38.

[0127] In contrast, FIG. 12 shows an embodiment example in which the connectors 38 connect holding sections 29a, 29c and 29b, 29d, respectively, and engagement elements 22a, 22c and 22b, 22d, respectively, on opposite lateral surfaces 11, 12. Accordingly, the connectors 38 extend transversely to the lateral surfaces 11, 12. Furthermore, the connectors 38 extend above fold edges 16. Two engagement elements 22a, 22c and 22b, 22d respectively form a separate part with two holding sections 29a, 29c and 29b, 29d respectively and one connector 38. In the embodiment example according to FIG. 12, the filter element 8 is completely embraced by the holding sections 29a to 29d together with the connectors 38.

[0128] In the embodiment example according to FIG. 13, the engagement elements 22a to 22d together with respective associated holding sections 29a to 29d are each designed as a separate part and are not connected to one another using connectors 38. In each case, two of the engagement elements 22a to 22d together with associated holding sections 29a to 29d are disposed on a sideband 11 or 12.

[0129] In the embodiment example according to FIG. 14, the engagement elements 22a to 22d are fixed to the filter element 8, even before the first assembly step (see step S1 according to FIG. 16). In particular, the engagement elements 22a, 22b or 22c, 22d are glued to, welded to or integrally formed with the sidebands 11 or 12. According to the embodiment example, the engagement elements are shaped as projections projecting outwardly from a respective sideband 11, 12, that is away from the filter element 8. The engagement elements 22a to 22d according to FIG. 14 are arranged, for example, to engage positively in the through holes 34 or corresponding pockets (see FIG. 6).

[0130] In the embodiment example according to FIG. 15, two respective engagement elements 22a, 22b or 22c and 22d are connected to one another using a connector 38, the connector 38 being fastened, in particular glued, to an associated side wall 11 or 12. In this case, the connector 38 can also be elastically designed in order to permit a change in the distance d (see FIG. 6).

[0131] In this case, FIGS. 11 to 15 each show a set 40 comprising a filter element 8 and engagement elements 22a to 22d. The set 40 is suitable for being used with a filter housing 7, such as shown in FIG. 6. A filter element already present there can be easily replaced using the set 40, preferably at least steps S1 and S2 being carried out in accordance with the method according to FIG. 16, optionally also step S3.

[0132] Although the present invention has been explained in more detail with reference to preferred examples of embodiments, it is not limited thereto, but can be modified in various ways. “One” does not exclude a plurality herein.

TABLE-US-00001 Reference Numbers 1 motor vehicle 2 air-conditioning system 3 outdoor air 4 air 5 passenger compartment 6 filter apparatus 7 filter housing 8 passenger compartment filter/filter element 9 filter medium/filter medium body 10 frame 11 sideband/lateral surface 12 sideband/lateral surface 13 headband 14 headband 15 fold 15a fold section 16 fold edge 17 end fold 18 end fold 19 fold front edge 20 fold front edge 21 seal 22a to 22d engagement elements 23 frame 24 wall section 25 wall section 26 wall section 27 wall section 28a to 28d engagement elements 29a to 29d holding sections 30 recessed area 31 insertion section 32 locking section 33 edge 34 through hole 35 symmetry axis 36 through hole 37 bend axis 38 connector 40 set 41a to 41d webs 42 edge 43 tab A1, A2 distances D distance d distance F1, F2 surfaces L throughflow direction RO raw side/inflow side RE clean side/outflow side