Filter element for an air filter having a primary air outlet and a secondary air outlet, air filter and assembly method
By designing a hollow cylindrical filter medium and a star-shaped pleated structure in the air filter, the primary and secondary air passages are separated, and an eccentric passage pipe is used for sealing connection, which solves the problem of mutual interference between passages in the air filter and improves the independence of air flow and filtration efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MANN HUMMEL GMBH
- Filing Date
- 2021-01-07
- Publication Date
- 2026-06-02
AI Technical Summary
In existing air filters, the crossflow at the primary air outlet is easily affected by the crossflow at the secondary air outlet, which affects the airflow velocity curve and flow rate.
An air filter element was designed, which uses a hollow cylindrical filter medium. A secondary air passage is formed by setting an axial recess on the first end plate, and the primary and secondary air passages are separated. The effective filtration area is increased by using a star-shaped folded filter medium. At the same time, an eccentric passage pipe is set in the filter housing and sealed to the outlet pipe.
This enables independent operation of the primary and secondary air passages, reducing mutual interference and ensuring that the airflow velocity and flow rate at the primary air outlet are not affected by the secondary air outlet, thereby improving the efficiency and reliability of the air filter.
Smart Images
Figure CN115038506B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a filter element for an air filter having an unpurified air inlet, a primary air outlet, and a secondary air outlet. The invention also relates to such an air filter and its assembly method. Background Technology
[0002] Air filters having a primary air outlet and a secondary air outlet for filtered air are used, for example, in the internal combustion engines of motor vehicles. The primary air outlet is typically used to provide (filtered) purified air for combustion in the internal combustion engine. The secondary air outlet can be used, for example, to provide (filtered) purified air for use in the exhaust gas lines of the internal combustion engine, particularly for exhaust aftertreatment.
[0003] EP 1 451 464 B1 describes an intake filter for an internal combustion engine, having a filter housing with an unpurified air inlet, a purified air outlet, and a purified secondary air outlet. The intake filter has an annular filter element arranged radially from the outside to the inside within the filter housing. The annular filter element has a first end plate at an axial end having at least one opening through which the purified air outlet communicates with the interior of the annular filter element. The annular filter element has a second end plate at an axial end opposite to the first end plate, the second end plate having at least one opening through which the secondary air outlet communicates with the interior of the annular filter element, wherein an attachment pipe is constructed on the second end plate.
[0004] A similar air filter is also known from WO 2017 / 103048 A1.
[0005] WO 2012 / 17-2017 A1 describes a filter element having an annular filter body that surrounds an internal space in a circumferential direction. A main connector is constructed in an end plate of the filter element, which is fluidly connected to the internal space. The filter body has a channel that extends axially and opens radially, wherein a secondary connector fluidly connected to the internal space is arranged in a region of the channel.
[0006] A filter element implemented as a flat filter is known from DE 10 2014 006 117 B4, wherein the filter media body of the filter element is curved and at least partially surrounds a flow space. The internal flow space communicates with the outside of the filter element via a flow nozzle. The flow nozzle extends radially about its longitudinal axis into a notch open on the edge side in the filter media body and partially protrudes beyond the end plate. Summary of the Invention
[0007] The objective of this invention is to provide an air filter having a primary air outlet and a secondary air outlet, and a filter element for the air filter, wherein the flow through the primary air outlet is substantially unaffected by the flow through the secondary air outlet.
[0008] This task is accomplished by a filter element having the features described in claim 1 and an air filter according to claim 13. Furthermore, the scope of the invention includes a method for assembling an air filter having the features described in claim 15, comprising an air filter having a primary air outlet and a secondary air outlet. Preferred embodiments or variations are given in the corresponding dependent claims and description.
[0009] According to the invention, a hollow cylindrical filter element is provided. The filter element has a filter medium. The filter medium circumferentially surrounds the longitudinal axis of the filter element. For the purpose of describing the invention, directional descriptions, such as radial, axial, or eccentric, refer to the longitudinal axis of the filter element unless otherwise stated. The filter medium can be flowed from the radial outside to the radial inside. Thus, the purification side of the filter element is radially constructed within the filter medium. The filter medium can be composed of cellulose fibers, synthetic fibers, glass fibers, or a mixture of the aforementioned fiber types. Furthermore, the filter element has a first end plate. The first end plate is, in principle, sealed and generally material-fitted to the filter medium. The filter medium can be welded to the first end plate (preferably by thermoplasticizing the first end plate, especially by means of infrared radiation), or bonded or foamed into the first end plate. The first end plate generally has an annular surrounding front side that extends in a plane preferably perpendicular to the longitudinal axis. The first end plate can be made of plastic or polyurethane foam.
[0010] The filter element has a primary air passage and a secondary air passage. The primary air passage is preferably constructed in the center of the filter element, especially coaxially with the longitudinal axis. Filtered air (purified air) can flow out from the interior of the filter element, that is, from the purified side, through the primary air passage and at least one secondary air passage.
[0011] According to the invention, the filter medium has an axial recess on its first end side. Apart from the recess, the filter medium is generally flat on its first end side. This recess creates a height increase or decrease in the filter medium relative to its otherwise typically flat first end side. Alternatively, in the region of the recess, the length of the filter medium body formed by the filter medium is reduced. A first end plate is generally arranged on the first end side. The first end plate has a channel forming a secondary air passage. The channel extends within the recess of the filter element. The channel forming the secondary air passage allows secondary airflow to spatially separate from the primary air passage from the purification side of the filter element. Therefore, the influence of the flow through the secondary air passage on the flow through the primary air passage can at least be reduced or preferably avoided. In particular, this can be achieved through a separate purified air passage, where the velocity profile of the airflow in the primary air outlet of the filter housing with the filter element is not significantly affected in quality, or at least not significantly affected by it, i.e., whether air flows through the secondary air passage and the secondary air outlet to which the filter housing belongs, or how large the volumetric or mass flow rate of the purified air is through the secondary air passage.
[0012] Preferably, the first end plate surrounds the channel at least partially, and preferably entirely, around the circumference. In other words, the channel can be confined by the first end plate around the entire circumference. Therefore, the channel is inherently sealed relative to the filter medium by the first end plate. No additional sealing of the channel relative to the filter medium is required. The wall surrounding the channel at least partially around the circumference is here constructed, in particular, as a single piece with the end plate.
[0013] The channel can extend radially relative to the longitudinal axis of the filter element. In particular, the entire channel can extend in a straight line. This is advantageous, especially in the manufacture of the first end plate and the filter media.
[0014] Alternatively, the channel may begin radially inward at the filter media and extend through the axial front of the first end plate. This is advantageous in arranging the secondary air outlet at the filter housing for the filter element. The channel may extend obliquely or in a curved manner along the longitudinal axis for this purpose.
[0015] Preferably, the recess tapers axially from the first end side. Therefore, the recess is constructed without a back cut. This simplifies the sealing connection between the first end disc and the filter media in the area of the recess.
[0016] The first end plate may have at least one sealing surface, preferably two sealing surfaces, to seal the filter medium at the recess. The filter medium may be embedded in or bonded to the sealing surface. Preferably, one (or more) sealing surfaces are inclined relative to the longitudinal axis. This simplifies the correct orientation of the first end plate at the recess, especially when the recess tapers in the axial direction.
[0017] The filter media is preferably folded in a star shape. This increases the effective filtration area of the filter media without increasing the external dimensions of the filter element. The folded edges of the filter media typically extend in the axial direction. The (axial) length of the folds in the filter media decreases relative to the rest of the folds in the recessed areas.
[0018] The recessed portion can be created by cutting the filter media using laser radiation, preferably a rolling blade, ultrasound, a band saw, or water jet cutting. When the filter media is folded in a star shape, it is typically cut before folding. In special cases, the filter media can also be cut after folding, especially when using ultrasound.
[0019] Typically, the filter element has a second end plate at the second end side. The first and second end sides are constructed at the filter element axially away from each other.
[0020] The primary air passage can be constructed in the second end plate. In this case, the primary and secondary air passages are separated from each other by a considerable distance, thereby reducing the mutual influence of the crossflow.
[0021] Preferably, the second end plate is constructed in a closed configuration. In this case, the primary air passage is constructed on the first end plate. This can be advantageous in terms of assembling the filter element in the filter housing. By separating the primary air passage from the secondary air passage, the mutual interference of crossflow is also sufficiently reduced in this embodiment.
[0022] The primary air passage can be formed, in particular, by a centrally located perforation in the first or second end plate, preferably coaxial with the longitudinal axis. In the region of the primary air passage, a sealing element can be held on the first or second end plate, particularly injection-molded onto it. The sealing element can be made of an elastomer or polyurethane foam.
[0023] It can be specified that the passage extends through a connecting pipe eccentrically arranged on the filter element. The connecting pipe simplifies the connection between the secondary air passage and the secondary air outlet of the filter housing. At least one end of the eccentric connecting pipe facing away from the filter element, preferably the entire connecting pipe, is not arranged on the longitudinal axis. The connecting pipe can protrude radially or axially from the filter element. Therefore, the connecting pipe protrudes beyond the axial front of the filter media or the first end plate in the radial or axial direction. In special cases, the connecting pipe can terminate flush with the filter element. The connecting pipe is typically constructed integrally with the first end plate.
[0024] A sealing element can be retained at the free end of the access pipe. Therefore, the sealing element is replaced along with the filter element. This ensures that the connection between the access pipe and the secondary air outlet of the filter housing has the required sealing characteristics after filter element replacement. The sealing element can be made of elastomer or polyurethane. Preferably, the sealing element is injection molded onto the access pipe or integrally formed with the access pipe.
[0025] Furthermore, the scope of the invention also includes an air filter. This air filter has a filter housing with an unpurified air inlet, a primary air outlet, and a secondary air outlet. Additionally, the air filter has the filter element described above according to the invention, which separates the unpurified side, communicating with the unpurified air inlet, from the purified side within the filter housing. The unpurified side and purified side may also be referred to as the unpurified space or the purified space. During operation of the air filter, unpurified air to be filtered flows into the unpurified side of the housing through the unpurified air inlet. Air passes through the filter medium from the unpurified side to the purified side, where contaminant particles can be separated from the air and trapped within the filter medium.
[0026] According to the present invention, the primary air outlet is connected to the purification side via a primary air passage, while the secondary air outlet is connected to the purification side via a secondary air passage. In other words, the primary air outlet is fluidly connected to the purification side via the primary air passage; the secondary air outlet is fluidly connected to the purification side via the secondary air passage. During the operation of the air filter, filtered purified air can be drawn from or flows out of the air filter from the purification side via the primary air outlet and the secondary air outlet. Here, the volumetric flow rate or mass flow rate of the purified air flowing through the primary air outlet is generally significantly greater than the volumetric flow rate or mass flow rate of the purified air flowing through the secondary air outlet. By structurally separating the secondary air passage and the primary air passage on the filter element according to the present invention, the influence of the flow through the secondary air outlet on the flow through the primary air outlet can be avoided or at least minimized.
[0027] An air filter can be part of an internal combustion engine, particularly in a motor vehicle. Filtered combustion air can be supplied to the internal combustion engine through the primary air outlet, especially where an air mass flow meter is arranged after the primary air outlet. Through a secondary air outlet, for example, an exhaust aftertreatment device can be attached to the air filter and supplied with filtered, purified air when needed.
[0028] When the channel extends through a particularly radially protruding access pipe arranged eccentrically at the filter element, the access pipe can be sealingly connected to the outlet pipe of the filter housing. A secondary air outlet is constructed at the outlet pipe. In particular, the outlet pipe can annularly surround the secondary air outlet. The outlet pipe typically protrudes inward beyond the housing wall of the filter housing. In other words, the outlet pipe typically extends from the housing wall into the internal space of the filter housing. A sealing element can be arranged between the outlet pipe and the access pipe. The outlet pipe at the filter housing simplifies the assembly of the filter element within the filter housing. On the other hand, the outlet pipe simplifies the attachment of the device to be supplied with secondary air at the air filter. For this purpose, the outlet pipe can protrude outward beyond the housing wall. In special cases, the outlet pipe terminates flush with the housing wall inward and / or outward.
[0029] Furthermore, the scope of the invention also includes a method for assembling an air filter according to the invention, wherein an eccentric passage pipe through which the channel extends is sealingly connected to an outlet pipe of the filter housing. The method includes the following steps:
[0030] a) Install the filter element into the housing element of the filter housing.
[0031] b) Rotate the filter element around the longitudinal axis to seal the inlet and outlet connections together.
[0032] Before performing step a), one housing element and another housing element may be detached from each other if necessary. This provides an inlet for inserting the filter element into the housing element. The housing element may be a housing canister or a housing cover. The other housing element may correspondingly be a housing cover or a housing canister.
[0033] In step a), a filter element is arranged on a housing element. The housing element typically has a primary air outlet and a secondary air outlet. Preferably, the filter element is installed into the housing element in the axial direction. Here, the primary air passage of the filter element is typically connected to the primary air outlet of the housing element. The passage connector and outlet connector are, in principle, arranged circumferentially offset from each other. The axial position of the filter element to be established in the filter housing in step a) can be defined by an axial stop.
[0034] In step b), the access pipe is sealed to the outlet pipe. Thus, a fluid connection between the secondary air outlet and the purified side of the filter element is established through a channel extending from the access pipe. This connection is easily achieved by rotating the filter element.
[0035] Preferably, the final rotational position to be established in step b) is defined by a rotation stop between the filter housing and the filter element. The rotation stop is typically constructed on the housing element. The rotation stop holds the filter element in the final rotational position. This ensures that the sealed connection between the inlet and outlet pipes does not accidentally come loose during air filter operation. In particular, the filter element can be locked onto the filter canister.
[0036] According to the method of the present invention, the assembly of the filter element is divided into two simple sub-movements. Simultaneously, the sealed connection established here between the outlet pipe and the passage pipe prevents the purified side and the unpurified side from unintentionally communicating with each other through the secondary air passage. Therefore, on the one hand, it prevents purified air from leaking from the purified side to the unpurified side, and on the other hand, it prevents unfiltered, unpurified air from flowing from the unpurified side to the purified side.
[0037] Typically, in step c), one housing element and another housing element are connected to each other. This closes the filter housing to the outside. Attached Figure Description
[0038] Other features and advantages of the invention will become apparent from the following detailed description of embodiments of the invention, from the claims, and from the accompanying drawings illustrating details according to the invention. The features mentioned above and to be further explained can be implemented individually or in any suitable combination in variations of the invention. The features shown in the drawings are illustrated such that the characteristics according to the invention are readily apparent. The drawings show:
[0039] Figure 1 An air filter according to the invention is shown in a schematic cross-sectional view. The air filter has a filter housing and a filter element according to the invention. A primary air outlet and a secondary air outlet are constructed on the filter housing. The filter element is arranged in the filter housing and has a filter medium and a first end plate. A primary air passage and a secondary air passage are constructed on the first end plate. The secondary air passage extends in the form of a channel in an axial recess of the filter medium.
[0040] Figure 2 Shown in another schematic cross-sectional view Figure 1 The filter element of the air filter;
[0041] Figure 3 A schematic perspective view is shown. Figure 1The filter element of the air filter;
[0042] Figure 4 A schematic flowchart of the assembly method according to the present invention is shown. Detailed Implementation
[0043] Figure 1 An air filter 10 is shown. The air filter 10 has a filter housing 12. The filter housing 12 may include a housing canister 14 and a housing cover 16. The filter housing 12 is in Figure 1 The diagram is shown in a highly abstract manner. The housing 14 and housing cover 16 are hermetically connected to each other for the operation of the air filter 10. The filter housing 12 has an unpurified air inlet 18, a primary air outlet 20, and a secondary air outlet 22. The unpurified air inlet 18 is located in the housing 14. The primary air outlet 20 and the secondary air outlet 22 are located in the housing cover 16. The filter housing 12 may be diagonally separated, as schematically indicated by wavy lines. The flow through the filter housing 12 is indicated by arrows.
[0044] The secondary air outlet 22 may be constructed at an outlet pipe 24. In the illustrated embodiment of the air filter 10, the outlet pipe 24 extends outward from the filter housing 12 on one hand and inward into the filter housing 12 on the other.
[0045] The primary air outlet 20 can be constructed on another outlet pipe 26. In the illustrated embodiment of the air filter 10, this other outlet pipe 26 extends outward from the filter housing 12 on one hand and inward into the filter housing 12 on the other.
[0046] Unpurified air inlet 18 may be constructed on inlet pipe 28. In the illustrated embodiment of air filter 10, inlet pipe 28 protrudes outward from filter housing 12.
[0047] Furthermore, the air filter 10 has a filter element 30. The filter element 30 is... Figure 2 China and Israel relative Figure 1 Another cross-sectional view rotated 90° is shown. Figure 3 The filter element 30 is shown in perspective.
[0048] The filter element 30 has a filter medium 32. The filter medium 32 annularly surrounds the longitudinal axis 33 of the filter element 30. The filter element 30 can be flowed from the radial outside to the radial inside. The filter medium 32 can be implemented in a star-shaped fold. The filter element 30 has a first end plate 36 at a first end side 34. The filter element 30 has a second end plate 40 at a second end side 38. The first and second end sides 34, 38 are located at the axially opposite ends of the filter element 30. The first and second end plates 36, 40 are hermetically connected to the filter medium 32, for example, by welding.
[0049] Inside the filter housing 12, the filter element 30 separates the unpurified side 42 from the purified side 44. The unpurified side 42 is the space outside the filter element 14. The purified side 44 is the space within the filter medium 32 and between the end plates 36 and 40. The second end plate 40 is constructed in a closed manner to separate the unpurified side 42 from the purified side 44. The unpurified side 42 can also be referred to as the unpurified space, and the purified side 44 can be referred to as the purified space. During the operation of the air filter 10, the unpurified air to be filtered flows to the unpurified side 42 through the unpurified air inlet 18. Air flows through the filter medium 32 from the unpurified side 42 and reaches the purified side 44 as filtered purified air.
[0050] The first end plate 36 has a primary air passage 46. The purified side 44 communicates with the primary air outlet 20 via the primary air passage 46. The primary air passage 46 may be surrounded by an annular protrusion 48. The protrusion 48 extends axially beyond the front surface 50 of the first end plate 36. The front surface 50 extends in a plane perpendicular to the longitudinal axis 33. A sealing element 52 may be retained on the protrusion 48, particularly injection molded onto the protrusion 48. The sealing element 52 seals the primary air outlet 20, and here another outlet connector 26, relative to the first end plate 36. The primary air passage 46 and the protrusion 48 may be arranged coaxially with the longitudinal axis 33.
[0051] The filter element 30 has a secondary air passage 54. The secondary air passage 54 is formed by a channel 56. The wall of the channel 56 can be integrally constructed with the first end plate 36 and generally surround the channel 56 in annular shape. In other words, the first end plate 36 can restrict the channel 56 over its entire circumference, see in particular. Figure 2 .
[0052] The filter medium 32 has a recess 58 on its first end side 34. In the region of the recess 58, the fold length of the filter medium 32, measured in the axial direction, is shorter than that in the rest of the circumferential region of the filter medium 32. In other words, the recess 58 forms a deepening portion in the filter medium 32 on the first end side 34. The recess can be obtained by laser cutting the filter medium before the star-shaped folds.
[0053] Channel 56 extends within recess 58. Here, channel 56 extends linearly, particularly in the radial direction about the longitudinal axis 33 of filter element 30. Channel 56 is arranged at least segmentally (here completely) between the front surface 50 of first end plate 36 and filter medium 32.
[0054] The channel 56 is open on one side toward the purification side 44. On the other hand, the channel 56 leads into the secondary air outlet 22 of the filter housing 12. The purification side 44 is connected to the secondary air outlet 22 via the secondary air passage 54. In other words, the channel 56 fluidly connects the purification side 44 and the secondary air outlet 22.
[0055] Channel 56 is constructed here within the access pipe 60. The access pipe 60 may be integrally constructed with the first end plate 36. The access pipe 60 protrudes beyond the filter medium 32 at its radially outer end. The access pipe 60 is airtightly connected to the outlet pipe 24, see [reference needed]. Figure 1 Therefore, passage 56 is fluidly connected to secondary air outlet 22. A sealing element (not shown in detail) can be arranged between passage connector 60 and outlet connector 24. The sealing element can be held on passage connector 60, particularly injection molded onto passage connector 60. The end of passage connector 60 pointing to secondary air outlet 22 is eccentrically, i.e., not on the longitudinal axis 33, positioned at filter element 30. Here, the end of passage connector 60 pointing to secondary air outlet 22 protrudes radially from filter element 30.
[0056] The recessed portion 58 may taper away from the first end side 34 in the axial direction, i.e. towards the second end side 38, as shown in particular. Figure 2 Here, the recess 58 is constructed in an approximately V-shape, wherein the tip of the "V" pointing to the second end 38 is rounded.
[0057] The first end plate 36 may have two sealing surfaces 62 for sealing the filter medium 32 in the region of the recess 58. The sealing surfaces 62 are arranged obliquely relative to the longitudinal axis 33. Thus, the sealing surfaces 62 are configured to face-fit against the side regions of the recess 58. In the deepest region of the recess 58, the filter medium 32 is sealed by the wall of the channel 56 opposite to the front surface 50. In the region of the recess 58, the filter medium 32 can be hermetically connected to the first end plate 36 in the same manner as in the remaining circumferential regions, for example, by welding, bonding, or embedding into the first end plate.
[0058] Figure 4 A flowchart illustrating the assembly method for an air filter is shown. The following example uses the aforementioned air filter 10; see also... Figures 1 to 3 The method will be explained.
[0059] In the first step 102, the filter element 30 is installed into the housing canister 14 of the filter housing 12. For this purpose, the housing cover 16 is removed from the housing canister 14. The installation of the filter element 30 is generally achieved in a substantially linear movement along the longitudinal axis 33. During installation, the passage pipe 60 of the filter element 30 does not, in principle, point towards the secondary air outlet 22 or the outlet pipe 24. Here, the first end plate 36 is inserted into another outlet pipe 26, wherein an airtight connection between the other outlet pipe 26 and the first end plate 36 can be obtained around the primary air passage 46.
[0060] In the next step 104, the filter element 30 is rotated relative to the filter canister 14 about the longitudinal axis 33 until the access pipe 60 and the secondary air outlet 22 or outlet pipe 24 are oriented correspondingly to each other. This establishes a sealing connection between the access pipe 60 and the outlet pipe 24. In particular, here (in Figure 1 (Not shown in detail) A sealing element may be arranged between the passage pipe 60 and the outlet pipe 24. The radial position of the filter element 30 in the housing tank 14 may be secured to the other outlet pipe 26 by guiding the protrusion 48 surrounding the primary air passage 46. Preferably, the final rotational position of the filter element 30 established in step 104 (in which the passage pipe 60 corresponds to the outlet pipe 24) is achieved by the filter element 30's (in Figures 1 to 3 (Not shown in detail) The retaining element is locked on the housing 14 to secure it.
[0061] Finally, in step 106, the housing cover 16 is fitted onto the housing tank 14. The housing cover 16 may secure the filter element 30 in the axial position relative to the housing tank 14, for example by means of an axial stop (not shown in detail), which works in conjunction with the second end plate 40.
Claims
1. A hollow-cylindrical filter element (30) with a filter medium (32) and a first end disk (36), the filter medium annularly surrounding a longitudinal axis (33) of the filter element (30), wherein The filter medium (32) is capable of being flowed from the radial outside to the radial inside and has multiple folds, wherein the filter element (30) has a primary air passage (46) and a secondary air passage (54) located at the center, characterized in that, The filter medium (32) has an axial recess (58) only on the first end side (34), the recess gradually narrowing in the axial direction from the first end side (34), and the axial length of the folded portion of the filter medium (32) in the region of the recessed portion (58) is reduced relative to the remaining folded portions. The first end plate (36) has a channel (56) forming the secondary air passage (54), the channel extending in the axial recess, wherein the channel (56) extends radially relative to the longitudinal axis (33) of the filter element (30). The first end plate (36) also has at least one sealing surface (62) for sealing the filter medium (32) at the recess (58), the sealing surface (62) being inclined relative to the longitudinal axis (33) and abutting against the side area of the recess (58).
2. The filter element (30) according to claim 1, characterized in that The first end plate (36) surrounds the channel (56) at least partially around its circumference, wherein the wall surrounding the channel (56) at least partially around its circumference is integrally formed with the first end plate (36).
3. The filter element (30) according to claim 1 or 2, characterized in that The channel (56) begins radially inward from the filter medium (32) and passes through the axial front of the first end plate (36).
4. The filter element (30) according to claim 1 or 2, characterized in that The first end plate (36) has two sealing surfaces (62) for sealing the filter medium (32) at the recess (58), wherein the two sealing surfaces (62) are inclined relative to the longitudinal axis (33).
5. The filter element (30) according to claim 1 or 2, characterized in that The filter medium (32) is folded in a star shape.
6. The filter element (30) according to claim 1 or 2, characterized in that The recess (58) is made by cutting the filter medium (32) using laser radiation, a rolling blade, ultrasound, a band saw, or water jet cutting.
7. The filter element (30) according to claim 1 or 2, characterized in that The filter element (30) has a second end plate (40) on the second end side (38).
8. The filter element (30) according to claim 7, characterized in that, The second end plate (40) is closed.
9. The filter element (30) according to claim 1 or 2, characterized in that, The primary air passage (46) is constructed on the first end plate (36).
10. The filter element (30) according to claim 1 or 2, characterized in that, The channel (56) extends through the access pipe (60) that is eccentrically arranged on the filter element (30).
11. The filter element (30) according to claim 10, characterized in that, A sealing element is maintained at the free end of the access pipe (60).
12. The filter element (30) according to claim 11, characterized in that, The sealing element is injection molded onto the access connector (60) or integrally constructed with the access connector (60).
13. An air filter (10), characterized in that, The air filter has: - A filter housing (12) with an unpurified air inlet (18), a primary air outlet (20) and a secondary air outlet (22). - The filter element (30) according to any one of the preceding claims, wherein the filter element separates the unpurified side (42) communicating with the unpurified air inlet (18) from the purified side (44) in the filter housing (12). The primary air outlet (20) is connected to the purification side (44) via the primary air passage (46), and the secondary air outlet (22) is connected to the purification side (44) via the secondary air passage (54).
14. The air filter (10) according to claim 13, characterized in that, The filter element (30) is constructed according to claim 10 or 11, and the access pipe (60) is hermetically connected to the outlet pipe (24) of the filter housing (12).
15. A method for assembling an air filter (10) according to claim 14, characterized in that, The method includes the following steps: a) The filter element (30) is installed axially into the housing element of the filter housing (12). b) Rotate the filter element (30) about the longitudinal axis (33) so that the inlet pipe (60) and outlet pipe (24) are sealed to each other.