Air filter and holder for an air filter

Abstract

A holder (72) for an air filter (10) having a substantially cylindrical filter housing (12), wherein a series of first structures (74) are provided on the periphery of the filter housing (12), and the holder (72) comprises: • at least two second structures (76) which are designed to engage with one of the first structures (74) and to connect the filter housing (12) in the assembled state to the holder (72) in a form-fitting manner; and • at least two base structures (78) for screwing the holder (72) to a mounting target structure, characterized in that a length of the holder (72) in the circumferential direction of the filter housing (12) is smaller than the circumference of the filter housing (12) and that the holder (72) is formed in one piece.

Description

[0001] The invention relates to an air filter, in particular for the intake air for internal combustion engines, and a holder for an air filter.

[0002] DE 19712679 A1 discloses an air filter comprising a filter housing and a substantially cylindrical filter element with an inner support tube, wherein the inner filter element is arranged coaxially within the filter housing. The filter element is sealed to the filter housing by means of annular cover plates made of polyurethane. The cover plate can be slid onto an inner section of an outlet part of the filter housing, where it creates a force-fitting connection between the filter element and the outlet part.

[0003] As is well known, the filter elements of air filters are replaced after a certain period of operation.

[0004] During normal operation, the filter element prevents dirt particles from the raw area of ​​the filter from penetrating the clean area of ​​the filter. Over time, however, encrusted dirt can collect on the walls of the filter housing, particularly at the transition to the filter element's cover plate. When a dirty filter element is removed, pieces of the encrustation can break off, collect at the bottom of the filter housing, and, after a new filter element is inserted, enter the clean area and / or impair the sealing effect of the cover plate. The encrustations can also, under certain circumstances, create an adhesive force that requires considerable force to break the force-locking connection between the filter element and the outlet part.

[0005] Other air filters of this type are known from WO9637277A1 and DE 4241586 A, which have two-part filter housings. The two filter housing sections are connected by metal brackets located on the sides of the filter housing, which must be opened and closed again to replace the filter element. The metal brackets must be accessible to the user, and sufficient space must be provided to the side of the filter housing in the engine compartment, which can be difficult under certain circumstances.

[0006] Furthermore, sufficient space must be provided in the axial direction to allow the filter element to be pulled out and inserted into the lower part of the filter housing.

[0007] EP 0976 932 A2 discloses a bracket for mounting an air filter in an engine compartment. The bracket is constructed in one piece and comprises a band that wraps around the cylindrical main body of the air filter. Mounting brackets are formed at the end regions of the band, which, when mounted, form a base-like mounting structure. Recesses with screw openings are provided in externally accessible openings in the mounting brackets. A series of projecting blocks on the inner circumference of the band engage in corresponding equidistant recesses on the outer circumference of the air filter housing, each of which defines one of several mounting rotational positions of the air filter. The length of the band of the bracket from EP 0976 932 A2 corresponds to the length of the circumference of the air filter and is therefore only suitable for air filters of a specific size. The shape of the bracket is relatively complex in terms of injection molding technology and requires a high material usage.

[0008] The invention is therefore based on the object of creating a holder for an air filter with improved properties, which is particularly flexible in use and can be easily manufactured by injection molding with minimal material usage. Furthermore, the invention is based on the object of providing an easily mounted air filter and a method for easily mounting an air filter.

[0009] The object is achieved by a holder having the features of claim 1 as well as by an air filter and a method using such a holder.

[0010] The invention is based on a holder for an air filter with a substantially cylindrical filter housing. The filter housing is designed such that a series of first structures are provided on the circumference of the filter housing. The holder comprises at least two second structures, each of which is designed to engage with one of the first structures and to connect the filter housing to the holder in a form-fitting manner when installed. Furthermore, the holder comprises at least two base structures for screwing the holder to a mounting target structure. Depending on the application, the mounting target structure can be a wall in an engine compartment, a body structure, an engine block, or the like.

[0011] It is proposed that a length of the holder in the circumferential direction of the filter housing be smaller than the circumference of the filter housing. In this context, "smaller" means that the length differs from the circumference of the filter housing by more than just the width of a joint gap, in particular less than three-quarters of the circumference. In particularly advantageous embodiments of the invention, the length is less than half the circumference, in particular less than one-third. This allows for a particularly compact, material-saving, and cost-effective holder to be realized.

[0012] In a preferred embodiment of the invention, it is proposed that the holder be formed in one piece. Costs can be saved by reducing the number of components.

[0013] It is further proposed that the holder is designed to be elastically deformed to establish the positive connection between the first structures and the second structures. The base structures can be tilted relative to one another, and after the first structures and the second structures have snapped into place, the base structures lie in their desired assembly position. The desired assembly position generally corresponds to a configuration with the undersides of the base structures aligned with one another. In particular, by screwing the holder to the assembly target structure, an elastic deformation of the holder necessary to release the positive connection can be blocked. This enables the holder to be easily snapped onto the filter housing in a desired rotational position of the filter housing. The connection is then locked by final assembly on the assembly target structure.

[0014] In a preferred embodiment of the invention, it is proposed that a bending direction of the elastic deformation necessary to produce the positive connection is opposite to a curvature direction of the outer circumference of the filter housing.

[0015] In a preferred embodiment, the first structures are projections and the second structures are openings. However, embodiments of the invention are also conceivable in which projections on the holder engage openings in the filter housing.

[0016] It is further proposed that the second structures be designed to interact with at least three first structures of the filter housing, wherein a central structure in the longitudinal direction of the holder serves to center the holder, and the holder engages behind the flanks of the two outer first structures facing away from the central structure. This simplifies assembly.

[0017] Further advantages can be realized if the bracket has walls in its end regions that, when mounted, run essentially parallel to the radial and axial directions of the filter housing. Furthermore, it is proposed that the walls be designed to engage behind the flanks of the two outer first structures facing away from a center point of the bracket. This allows for a claw-like geometry that enables robust assembly.

[0018] In a particularly advantageous embodiment of the invention, the holder is designed as a one-piece plastic injection-molded part. This enables extremely cost-effective production. The structure of the holder according to the invention enables, in particular, the production of the holder in injection molds with few slides, in particular with only one slide or with no slide at all.

[0019] A further aspect of the invention relates to an air filter with a filter housing and a holder of the type described above. The air filter is in particular equipped with the first structures which are designed to establish a positive connection with the holder.

[0020] A further aspect of the invention relates to a method for assembling an air filter of the type described above. The method comprises the steps of establishing the positive connection between the first structures of the filter housing; and screwing the base structures to an assembly target structure.

[0021] Possible materials for the holder are in particular polyolefins, such as polyethylene and polypropylene or other thermoplastics such as acrylonitrile butadiene styrene (ABS), polyamides (PA), polylactate (PLA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyetheretherketone (PEEK) and polyvinyl chloride (PVC).

[0022] Further features and advantages will become apparent from the following description of the figures. The entire description, the claims, and the figures disclose features of the invention in specific embodiments and combinations. Those skilled in the art will also consider the features individually and combine them into further combinations or subcombinations in order to adapt the invention, as defined in the claims, to their needs or specific areas of application.

[0023] Showing: Fig. 1 shows an air filter according to a first embodiment of the invention in a sectional view; Fig. 2 a detailed view of a bottom area of ​​a housing pot of the air filter from Fig. 1 in a sectional view; Fig. 3 a detailed view of a housing cover of the air filter from Fig. 1 and Fig. 2 in a sectional view; Fig. 4 a detailed view of a housing cover of the air filter from Fig. 1 and Fig. 2 in an open state of a sectional view; Fig. 5 a detailed view of a housing cover of the air filter from Fig. 1 and Fig. 2 in a closed state of a sectional view; Fig. 6 a perspective view of the air filter from the Fig. 1 - 5 with a fixed bracket; Fig. 7 a perspective view of the air filter from the Fig. 1 - 5 with a loose bracket; Fig. 8 a detailed view of the bracket from the Fig. 6 and Fig. 7; and Fig. 9a - 9d schematic illustrations for the assembly of the air filter according to the invention.

[0024] The Fig. 1 - 8 show an air filter 10 according to a first embodiment of the invention.

[0025] Fig. 1 shows the air filter 10 in a sectional view. The air filter 10 comprises a substantially cylindrical filter housing 12 with a housing bowl 14 and a housing cover 16. The housing bowl 14 contains a raw air inlet 18 and a clean air outlet 20 arranged essentially concentrically on a first end face of the filter housing 12. At the clean air outlet 20, an extension tube 22 extends into the interior of the filter housing 12. The filter element comprises a first cover plate 24 that can be plugged onto the extension tube 22. The first cover plate 24 is made of polypropylene plastic.

[0026] A deflection wall (dip tube) is provided in the area of ​​the raw air inlet 18. In conjunction with the raw air inlet 18, which leads tangentially into the filter housing 12, a swirling flow of the raw air is created. This causes coarse dust particles to separate, with these coarse dust particles moving downward along the inner wall of the filter and being discharged to the outside via a dust discharge opening, which is closed with a known dust discharge valve.

[0027] In the filter housing 12, a safety element 26 is arranged fixed to the housing, which comprises a metal grid (in particular expanded metal) and a fleece layer.

[0028] A filter element 28 is pushed over the safety element 26. This filter element 28 carries the first cover plate 24 on its first end face. A radially inwardly projecting sealing lip 30 is formed on the cover plate 24, which, when plugged in, rests against the extension tube 22 and seals around it.

[0029] The sealing lip 30 projects from a base ring of the first cover plate 24 and is in the Fig. 1, the sealing lip 30 is inclined axially from the base ring toward the first end face of the filter housing 12. The extension tube 22 comprises an outer profile that widens toward the first end face of the filter housing 12, so that the sealing lip 30 is guided and widened when the filter element 28 is plugged onto the extension tube 22. During this plugging movement, any dirt particles adhering to the outer profile of the extension tube 22 are pushed away and cannot enter the clean area of ​​the air filter 10.

[0030] A connection piece 32 for a bend or a straight clean air outlet 20 is arranged in the inner profile of the extension pipe 22, in which a maintenance switch 33 is provided. The connection piece 32 can be freely mounted circumferentially in the cylindrical inner profile of the extension pipe 22. An end ring 34 of the safety element 26 is connected to the connection piece 32 via a snap-in connection. The attached filter element 28 prevents the locking tabs of the connection piece 32 from deflecting radially outward, so that the safety element 26 is locked to the connection piece 32.

[0031] When assembling the entire filter, the safety element 26 is first inserted, then the filter element 28 is pushed over it and the housing cover 16 is put on.

[0032] The filter housing 12 further comprises a dust discharge opening 36 with a dust emptying valve 38 attached thereto ( Fig. 1). This dust removal valve 38 has a lip opening in its lower area. When pressure pulsations occur that feed back into the filter housing 12 via the clean air outlet 20 from an internal combustion engine, this lip opening opens briefly, allowing the dirt accumulated in the dust removal valve 38 or the lower area of ​​the housing cover 16 to escape.

[0033] Fig. 2 shows a detailed view of a bottom area of ​​a housing pot of the air filter from Fig. 1 in a sectional view. The first cover plate 24 has a cylindrical ring-shaped spacer structure 40 that projects axially toward the first end face and axially projects beyond the sealing lip 30. The axial height of the spacer structure 40 is selected such that, when the filter element 28 is assembled, a gap remains between the spacer structure 40 and the filter housing wall. During transport and assembly of the filter element 28, the spacer structure 40 protects the sealing lip 30, while the gap allows axial expansion of the filter element 28.

[0034] The first cover plate 24 comprises a second sealing lip 42 formed thereon, projecting radially outward obliquely in the direction of the first end face of the filter housing 12, which, when plugged on, rests against an inner surface of a separating tube 44.

[0035] Fig. 3, Fig. 4 and Fig. 5 show various detailed views of a housing cover of the air filter from Fig. 1 and Fig. 2 in a sectional view.

[0036] The filter element 28 comprises a second cover plate 48, which is arranged at the end of the filter element 28 opposite the first cover plate 24. Like the first cover plate 24, the second cover plate 48 is made of plastic and is glued to a filter bellows 48 of the filter element 28, which is made of cellulose.

[0037] The second cover plate 24 comprises a support ring 50 arranged on a radial outer surface of the filter element 28 for radially and axially securing the filter element 28 in the filter housing 12. The support ring 50 is formed integrally with the second cover plate 46. The support ring 50 comprises an outer ring 52, which is connected to an inner ring 56 via radially extending ribs 54. The ribs 54 are arranged obliquely in the direction of the cyclone flow and delimit a dust collection area 58 in front of the dust discharge opening 36 and the dust emptying valve 38.

[0038] The support ring 50 is designed to rest in an assembled state on a shoulder 60 on the inner circumference of the housing pot 14 ( Fig. 4 and Fig. 5).

[0039] On an upper edge of the housing pot 14 there are retaining tabs 62 with radially inwardly projecting projections 64, which are arranged so high that they encompass the support ring 50 when the support ring 50 rests on the shoulder 60.

[0040] The housing cover 16 has a conical inner surface 66 at its lower edge, which is shaped such that, when fitted, the inner surface 66 blocks radially outward deflection of the retaining tabs 62. The support ring 50 is therefore axially fixed between the shoulder 60 and the projections 64.

[0041] Due to the conicity of the inner surface 66, the retaining tabs 62 are deflected radially inwards when the housing cover 16 is placed on and the support ring 50 is radially fixed between the inner surfaces of the retaining tabs 62.

[0042] Since the support ring 50 is formed integrally with the second cover plate 46, which is arranged at an end of the filter element 28 facing the housing cover 16, a direct transmission of force from the second cover plate 46 to the housing pot 14 is possible when the support ring 50 is fixed. A groove for receiving a sealing ring (not shown) is also provided at the lower edge of the housing cover 16.

[0043] A connecting screw 68 is provided in the housing cover 16 for connecting the housing cover 16 to the second cover plate 46 of the filter element 28. The second cover plate 46 has an internal thread into which the external thread of the connecting screw 68 engages. By tightening the connecting screw 68, the housing cover 16 is pulled in the direction of the housing pot 14 by force transmission via the support ring 50 axially fixed between the shoulder 60 and the projections, provided that the projections of the retaining tabs 62 engage over the upper edge of the support ring 50. If the filter element 28 is only partially inserted and the projections 64 of the retaining tabs 62 rest against the radial outer surface of the support ring 50, the retaining tabs 62 are deflected outwards so far that the housing cover 16 cannot be put on.

[0044] The connecting screw 68 comprises an inner part and an outer part which are connected via a ratchet coupling which forms a torque limiting mechanism 73.

[0045] The Fig. 6 - 8 schematically show a holder 72 of the air filter 10 according to the invention. The filter housing 12 is designed such that a series of first structures 74, which are essentially designed as block-like projections, are provided on the circumference of the filter housing 12. The holder 72 is a one-piece, elongated plastic injection-molded part and comprises a second, claw-like structure 76 at each of its two longitudinal ends. The claw-like structures 76 are designed such that they can each engage with one of the first structures 76 and, in the assembled state, form-fit the filter housing 12 to the holder 72. Since a total of eight of the first structures 76 are evenly distributed over the circumference of the filter housing 12, the holder 72 can be fastened to the filter housing 12 in eight different positions, each of these positions corresponding to a rotational position of the filter housing 12.

[0046] Furthermore, the holder 72 comprises at least two base structures 78, each arranged below the claw-like second structures 76, for screwing the holder 72 to a mounting target structure (not shown). The two ends of the holder 72 are connected by two side walls 80, the lower edge of which, facing the mounting target structure, is straight and the circular upper edge of which follows the curvature of the filter housing 12, so that the filter housing 12 rests on the upper edge in the mounted state.

[0047] A length of the holder 72 in the circumferential direction of the filter housing 12 is smaller than the circumference of the filter housing 12. In the Fig. 6 - 8 In the illustrated embodiment, the length is approximately one third of this circumference.

[0048] The holder 72 can be elastically deformed to establish the positive connection between the first structures 74 and the second structures 76, wherein the base structures 78 are tilted relative to one another, and after the first structures 74 and the second structures 76 snap into place, the base structures 78 are in their aligned desired assembly position. By screwing the holder 72 into screw holes 82 of the base structures 78 on the assembly target structure, an elastic deformation of the holder 72 necessary to release the positive connection is blocked, and a secure connection of the air filter 10 to the assembly target structure is established.

[0049] A bending direction of the elastic deformation necessary to establish the positive connection is opposite to a curvature direction of the outer circumference of the filter housing 12. The claw-like second structures 76 are hollow structures, each with an opening into which the first structures 74, designed as projections, engage.

[0050] A central structure 82 of the holder 72, located in the longitudinal direction of the holder 72, interacts with a projection 74 on the filter housing 12, which is located midway between the two projections 74 that engage the openings of the second structures 76. The central structure 82 serves to center the holder 72.

[0051] The holder 72 has in its end regions each end-face walls 84 which, in the assembled state, run essentially parallel to the radial and axial direction of the filter housing 12 and which are designed to engage behind flanks of the two outer first structures 74 facing away from a center point of the holder 72.

[0052] The Fig. 9a - 9d show once again schematically the steps for mounting the filter housing 12 on an assembly target structure ( Fig. 9d).

[0053] In Fig. 9a, the filter housing 12 and the holder 72 are shown separately.

[0054] Fig. 9b shows the holder 72 in an elastically deformed configuration when the second structures 76 are snapped over the outer first structures 74 of the filter housing 12, wherein the middle structure 82 centers the holder relative to the filter housing 12 and is inserted over a middle one of the first structures 72 of the filter housing 12.

[0055] Fig. 9c shows the holder 72 after snapping the second structures 76 over the outer first structures 74 of the filter housing 12 and Fig. Figure 9d shows the filter housing in the assembled configuration on the assembly target structure after screwing fastening screws into the base structures 78.

Claims

[1] A holder (72) for an air filter (10) having a substantially cylindrical filter housing (12), wherein a series of first structures (74) are provided on the periphery of the filter housing (12), and the holder (72) comprises: • at least two second structures (76) which are designed to engage with one of the first structures (74) and to connect the filter housing (12) in the assembled state to the holder (72) in a form-fitting manner; and • at least two base structures (78) for screwing the holder (72) to a mounting target structure, characterized by , that a length of the holder (72) in the circumferential direction of the filter housing (12) is smaller than the circumference of the filter housing (12) and that the holder (72) is formed in one piece. [2] Holder (72) according to claim 1, characterized byin that the holder (72) is designed to be elastically deformed in order to produce the positive connection between the first structures (74) and the second structures (76), wherein the base structures (78) are tilted relative to one another, and after the first structures (74) and the second structures (76) have snapped into place, the base structures (78) are in their desired assembly position and an elastic deformation of the holder (72) necessary for releasing the positive connection is blocked by screwing the holder (72) to the assembly target structure. [3] Holder (72) according to claim 2, characterized by that a bending direction of the elastic deformation necessary to produce the positive connection is opposite to a curvature direction of the outer circumference of the filter housing (12). [4] Holder (72) according to one of the preceding claims, characterized bythat the first structures (74) are projections and the second structures have openings (76) for receiving the first structures (74). [5] Holder (72) according to one of the preceding claims, characterized by in that the second structures (76) are designed to interact with at least three first structures (74) of the filter housing (12), wherein a middle structure (74) in the longitudinal direction of the holder (72) serves to center the holder (72) and the holder (72) engages behind the flanks of the two outer first structures (74) facing away from the middle structure (74). [6] Holder (72) according to one of the preceding claims, characterized bythat the holder (72) has walls (84) in each of its end regions which, in the mounted state, run essentially parallel to the radial and axial direction of the filter housing (12) and which are designed to engage behind flanks of the two outer first structures (74) facing away from a center point of the holder (72). [7] Holder (72) according to one of the preceding claims, characterized by that the holder (72) is designed as a one-piece plastic injection-molded part. [8] Air filter with a filter housing (12) and a holder (72) according to one of the preceding claims. [9] A method for assembling an air filter (10) according to claim 8, comprising the steps of: • Producing the positive connection between the first structures (74) of the filter housing (12) and the second structures (76) of the holder (72) by elastic deformation and snapping; and • Screwing the base structures (78) to an assembly target structure.

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