Filter Element, Interior Air Filter and Production Method

Abstract

A filter element is provided with a pleated structure of a filter material folded in a zigzag shape. A frame element is attached to the pleated structure and at least partially circumferentially extends around the pleated structure. The frame element is air-permeable and laterally projects away from the pleated structure. A frame device is attached to the frame element. The frame device is an injection-molded plastic part injection molded onto the frame element. In a method for producing the filter element, an air permeable frame element is attached to the pleated structure of a filter material folded in a zigzag shape so as to circumferentially extend at least partially around the pleated structure and project laterally. The frame device is injection molded onto the frame element in an injection molding process. A filter assembly is provided with a filter housing and the filter element is received in the filter housing.

Claims

1. A filter element comprising: a pleated structure comprising a filter material folded in a zigzag shape; a frame element attached to the pleated structure and at least partially circumferentially extending around the pleated structure, wherein the frame element is air-permeable and laterally projects away from the pleated structure; a frame device attached to the frame element, wherein the frame device is an injection-molded plastic part injection molded onto the frame element.

2. The filter element according to claim 1, further comprising a lateral band attached to fold profiles of the pleated structure, wherein a projecting section of the lateral band projecting laterally past a width and/or a height of the pleated structure forms a part of the frame element.

3. The filter element according to claim 2, wherein the projecting section of the lateral band projects laterally past the height of the pleated structure away from the pleated structure.

4. The filter element according to claim 2, wherein the lateral band comprises a leg that is attached to the fold profiles of the pleated structure, wherein the frame element is free of injection-molded material of the frame device in a transition region to the leg of the lateral band.

5. The filter element according to claim 1, further comprising a head band attached to an end fold section of the pleated structure, wherein a projecting section of the head band projecting laterally past a width and/or a height of the pleated structure forms a part of the frame element.

6. The filter element according to claim 5, wherein the projecting section of the head band projects laterally past the height of the pleated structure away from the pleated structure.

7. The filter element according to claim 5, wherein the head band comprises a leg that is attached to the end fold section of the pleated structure, wherein the frame element is free of injection-molded material of the frame device in a transition region to the leg of the head band.

8. The filter element according to claim 1, wherein the pleated section comprises an end fold section comprising a projecting section projecting laterally past a length and/or a height of the pleated structure, wherein the projecting section forms a part of the frame element.

9. The filter element according to claim 8, wherein the projecting section projects laterally past the height of the pleated structure away from the pleated structure.

10. The filter element according to claim 8, wherein the end fold section comprises a section corresponding to the height of the pleated structure, wherein the frame element is free of injection-molded material of the frame device in a transition region to the section corresponding to the height of the pleated structure.

11. The filter element according to claim 1, wherein the frame element projects laterally past a height of the pleated structure away from the pleated structure.

12. The filter element according to claim 1, wherein the frame device projects laterally past a height of the pleated structure away from the pleated structure.

13. The filter element according to claim 1, wherein the frame device is attached exclusively by injection molding to the frame element.

14. The filter element according to claim 13, wherein the frame device is not directly injection molded onto fold edges of the pleated structure and/or fold profiles of the pleated structure.

15. The filter element according to claim 1, wherein the frame element comprises or is comprised of a nonwoven material.

16. The filter element according to claim 15, wherein the nonwoven material is a spunbond nonwoven and comprises at least proportions of synthetic fibers.

17. The filter element according to claim 15, wherein the nonwoven material comprises one or more properties selected from the group consisting of an air permeability at 200 Pa between 200 and 3,500 l/m.sup.2s; a thickness between 1 and 6 mm; and a weight per surface area between 100 and 500 g/m.sup.2.

18. The filter element according to claim 1, wherein the frame element is embodied as a strip or as a band or is of a flat configuration and extends along a length side and/or a width side of the pleated structure.

19. The filter element according to claim 1, wherein the frame device surrounds the pleated structure and is configured to radially seal along a flow direction through the filter element.

20. A method for producing a filter element, the method comprising: attaching an air permeable frame element to a pleated structure of a filter material folded in a zigzag shape so as to circumferentially extend at least partially around the pleated structure and to project laterally; injection molding a frame device onto the frame element in an injection molding process.

21. A method according to claim 20, further comprising clamping the frame element in an injection molding tool along a separation contour of the injection molding tool such that no material of the frame device can reach directly fold edges and/or fold profiles of the pleated structure during the injection molding process.

22. A filter assembly comprising: a filter element according to claim 1; a filter housing configured to receive at least partially the filter element; wherein the frame device of the filter element is clamped at a housing separation line of the filter housing axially along a flow direction of the filter element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG. 1 shows a schematic illustration of a general motor vehicle with an interior air filter.

[0046] FIG. 2 shows a perspective illustration of a filter material.

[0047] FIG. 3 shows a schematic view of a pleated structure according to an embodiment.

[0048] FIG. 4 shows a schematic view of a filter element according to an embodiment in a plan view.

[0049] FIG. 5 shows a cross section A-A of FIG. 4.

[0050] FIG. 6 shows a side view with a rim-side cut-away section of FIG. 4.

[0051] FIG. 7 shows an enlarged detail Z of FIG. 6.

[0052] FIG. 8 shows a detail of a schematic view of an injection mold for producing a filter element of FIGS. 4 - 7.

PREFERRED EMBODIMENTS

[0053] FIG. 1 shows a motor vehicle 100 with an air conditioning device that comprises a filter assembly 10. For example, the air conditioning device can be designed as a heating/air conditioning device. The air conditioning device or the filter assembly 10 takes in ambient air 11 and supplies filtered air 12 to a cabin 13 (also referred to as passenger compartment) of the motor vehicle 100. Filtration is realized by a filter element 1 which is formed as an interior air filter.

[0054] FIG. 2 shows a folded filter material 3 in isolation and can be referred to in the illustrated form as a pleated structure 2. The filter material 3 is, for example, a filter nonwoven, filter fabric, laid filter material or filter felt, in particular a needled felt. In particular, the filter material 3 can be produced by a meltblown method. The filter material 3 can comprise natural fibers, such as cotton, or plastic fibers, for example, of polyester, polyphenyl sulfide or polytetrafluoroethylene. The fibers can be oriented during processing in, at a slant to and/or transverse to the machine direction M. Also, the fibers can be stretched in a spatial direction. The filter material 3 can be of a single-layer or multi-layer configuration.

[0055] For forming the pleated structure 2, the filter material 3 comprises folds 6 which extend typically transverse to the machine direction M. The folded filter material 3 is also referred to as pleating. The folds 6 can be generated by means of folding along sharp fold edges 7, 8 (also referred to as fold tips) or by a corrugated embodiment of the filter material 3. One can see in FIG. 2 upper fold edges 7 and, in the orientation of FIG. 2, bottom-side fold edges 8. A respective fold 6 can be defined by two neighboring fold sections 5 which are connected to each other by a corresponding fold edge 8. The fold structure is designed as a zigzag fold structure. Thus, a zigzag-shaped fold profile 4, 9 is realized at the sides of the pleated structure 2.

[0056] Also, a fold structure in which the folds 6 comprise a variable height H is possible. Moreover, the fold distance C between the folds 6 or the neighboring fold edges 7, 8 of identical fold orientation can vary. The filter material 2 can be designed to be self-supporting, i.e., the folds 6 are shape-stable upon intended flow during filtering operation.

[0057] The filter material 3 is delimited in machine direction M by end fold sections 5A, 5B. Transverse thereto, the filter material 3 is delimited by lateral end face fold edges (also referred to a fold profiles 4, 9). “End face fold edge” refers to the lateral edge of the filter material 3 at the side of the pleated structure 2 which extends between neighboring fold edges 7, 8 of a respective fold 6.

[0058] The filter material 3 can comprise a rectangular shape in the plan view, i.e., in the plane E of its flat extension. However, a triangular, pentagonal or polygonal, round or oval shape is conceivable also.

[0059] In the illustration of FIG. 2, a length L of the pleated structure 2 along the machine direction M and transverse to the fold edges 7, 8 is indicated. Along the fold edges 7, 8 and transverse to the machine direction M, a width B of the pleated structure 2 is usually indicated.

[0060] For producing a filter element, for example, an interior air filter element, a circumferentially extending frame element is attached to the pleated structure 2 illustrated in FIG. 2. In FIG. 3, the pleated structure 2 illustrated in FIG. 2 is indicated with top-side fold edges 7. Lateral bands 14, 15 are applied to the fold profiles 4, 9. The lateral bands 14, 15 have each an L profile with a section or leg 14A, 15A that is, for example, glued to the fold profiles 4, 9, and a laterally projecting section or leg 14B, 15B. The laterally projecting lateral band sections or legs 14B, 15B are part of a frame element. The legs 14A, 15A extending vertically in the orientation of FIG. 2 correspond to the height H of the pleated structure 2.

[0061] At the head side, oriented in the orientation of FIG. 3 forwardly to the right, the pleated structure 2 is closed off by a head band 16. The head band 16 comprises in turn a section or leg 16A corresponding to the height H of the pleated structure 2 and a laterally projecting section or leg 16B. At the head section of the pleated structure 2 opposite the head band 16 and indicated at the top to the left in the orientation of FIG. 3, the end fold section 5A has a projecting leg 5C which is projecting past the height H and the length L of the pleated structure 2. The leg 5C is separated from the end fold section 5A by a fold edge.

[0062] The sections 5C, 14B, 15B, 16B which are projecting respectively past the height H have a width b which makes it possible that a fixed connection to the injection molded material can be realized in a subsequent injection molding process. In this respect, FIG. 3 shows a pleated structure 2 at which a frame element laterally projecting from the pleated structure 2 is formed. The frame element is here formed by the four projecting sections 5C, 14B, 15B, and 16B.

[0063] At the projecting sections 5C, 14B, 15B, 16B, as illustrated in FIG. 4, a frame device 17 is formed. In FIG. 4 showing a plan view of the embodied filter element 1, the frame device 17 is wider in its lateral extension than the width B of the pleated structure 2 and longer than the length L of the pleated structure 2. In the illustration of FIG. 4, the projecting sections 5C, 14B, 15B, 16B inside the frame device 17 are molded around or embedded by the material of the frame device 17.

[0064] The filter element 1 in the embodiment of FIG. 4 shows moreover two adhesive traces 18 that, for example, are formed of a hot melt material and applied parallel to the length of the filter element 1 on the upper fold edges and the intermediately positioned fold sections. The adhesive traces 18 stabilize the fold spacings and penetrate, for example, into the folds.

[0065] In FIGS. 5, 6, and 7, further illustrations of the filter element 1 are represented. FIG. 5 shows a cross section view A-A. One can see in FIG. 5 the lateral band sections 14A, 15A and their projecting sections 14B, 15B. The projecting sections 14B, 15B acting as frame elements are oriented in the orientation of FIG. 5 at a slant upwardly and laterally away from the pleated structure 2. To the left and to the right in FIG. 5, one can see the cross section profile of the frame device 17 wherein the frame elements or the projecting sections 14B, 15B are enclosed. Moreover, at the center, the adhesive traces 18, for example, of hot melt, are illustrated and the lower fold edges 8.

[0066] FIG. 6 shows a view of the filter element 1 transverse to the cross section direction A-A viewing the lateral band 14. To the left, a cut-away section Z is indicated that exposes the fold profiles 4. Moreover, a head band 16A can be seen at the left side. FIG. 7 shows an enlarged detail of the cut-away section Z of FIG. 6. One can see that the frame device 17 is injection molded onto the section 16B in an injection molding process. In the orientation of FIG. 7, the frame device 17 comprises in this context a left axial seal section 17B and a fastening section 17A in which the projecting section 16B or the part 16B of the frame element is embedded. The projecting sections which are not illustrated are fastened analogously to the frame device 17 along the length of the filter element.

[0067] The frame device 17 contacts in this context neither the fold edges nor material sections of the filter element 1 below the height H of the folds. The configuration of the frame or of the frame device 17 prevents that filter surface is lost due to material of the frame 17 molded around during injection molding. The flow direction S through the filter element is realized from the top to the bottom in the orientation of FIGS. 5, 6, and 7.

[0068] In a filter assembly, the filter element 1 is received in a housing. FIG. 7 shows a part of the housing with a top housing section 24 and a bottom housing section 25. Between these two sections 24, 25, there is a separation line or separation contour of the housing 24, 25. In the installed state of the filter element 1, the seal section 17B of the frame device 17 is engaged or axially clamped at the separation contour 26, 27 of the housing. In this way, a safe sealing action between the raw fluid region and the clean fluid region of the resulting filter assembly 1 is ensured.

[0069] In a production process of the filter element 1, the frame device 17 is produced in particular by use of an injection mold in an injection molding process. FIG. 8 show shows now a detail of a schematic view of an injection mold or of an injection molding tool 19, 20 for producing a filter element 1 as it has been described before. For ease of illustration, only the section 14B, 15B or 16B projecting away from the pleated structure is indicated to the right in FIG. 8 inside of a cavity 23 of the injection molding tool 19, 20. One can see moreover a portion of the sections 14A, 15A or 16A corresponding to the height of the pleated structure, arranged vertical in the orientation of FIG. 8.

[0070] In a transition region between the vertical section 14A, 15A, 16A of the lateral band or head band and the respective projecting section 14B, 15B or 16B, the material of the lateral band or head band is clamped by the two tool parts 19, 20. This is realized along a separation contour 22 of the injection molding tool. A further separation contour 21 is indicated in FIG. 8 to the left adjacent to the cavity 23.

[0071] The injection molding tool or the tool bottom part 19 and the tool top part 20 are pressed against each other along the separation contours 21, 22 with clamping of the projecting section 14B, 15B, 16B. Subsequently, injection of the plastic material forming the frame device 17 is realized. After hardening of the injection molding material, by avoiding a contamination of the pleated structure with this material, the frame device 17 inclusive a suitable seal contour (compare FIG. 7) is produced.

[0072] For improved seal properties in radial but also in axial direction, a two-component injection molding method can be employed also. As a whole, the proposed production process provides for a simple production of filter elements, in particular for the use in the field of interior air filters.

LIST OF REFERENCE CHARACTERS

[0073] 1 filter element/interior air filter [0074] 2 pleated structure [0075] 3 filter material [0076] 4 fold profile [0077] 5 fold section [0078] 5A, 5B end fold section [0079] 5C frame element [0080] 6 fold [0081] 7, 8 fold edge [0082] 9 fold profile [0083] 10 filter device [0084] 11 raw air [0085] 12 filtered air [0086] 13 cabin [0087] 14 (14A, 14B) lateral band [0088] 15 (15A, 15B) lateral band [0089] 14B, 15B frame element [0090] 16 (16A, 16B) head band [0091] 17 frame device [0092] 17A fastening section [0093] 17B seal section [0094] 18 adhesive trace [0095] 19, 20 injection molding tool [0096] 21, 22 tool separation [0097] 23 cavity [0098] 24, 25 housing parts [0099] 26, 27 separation contour of housing [0100] 100 vehicle [0101] b projecting length [0102] B width [0103] C fold distance [0104] E plane [0105] H height [0106] L length [0107] M machine direction [0108] S flow direction