air cleaner

Abstract

To provide an air cleaner whose capacity is easily increased.SOLUTION: An air cleaner 10 has a first case 1, a second case 2, and a filter element 3 having a flat plate shape. The filter element is sandwiched between the first case and the second case. The filter element 3 has an annular seal part 4 in a peripheral edge. At least the first case 1 is provided with an annular flange part 12 in contact with the seal part 4. In at least a partial section of a peripheral edge of the first case 1, the flange part 12 extends to the inside of the case along an extending direction of the filter element 3 from an end 11a of a case wall 11, and a guide wall 13 is provided so as to be nearly parallel to the case wall 11 along a direction orthogonal to the extending direction of the filter element 3 from an end 13a of the flange part 12 inside the case. The case wall 11, the flange part 12, and the guide wall 13 have an approximately U-shaped cross section.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an air cleaner, and more particularly to an air cleaner having a flat filter element. [Background technology]

[0002] Air cleaners are used to filter and purify air to be supplied to internal combustion engines, air to be supplied to fuel cells, air used as cooling air, etc. Air cleaners equipped with flat filter elements are widely used in automobiles and the like.

[0003] A flat filter element is typically sandwiched between an upper case and a lower case to form an air cleaner, and air passing through the air cleaner is filtered by the filter element. Usually, a ring-shaped seal is provided around the periphery of the filter element to seal between the case and the filter element and prevent contaminated air from entering from outside. For example, Patent Document 1 discloses that an air cleaner is configured so that the outer peripheral frame of a filter medium is sandwiched between a flange of a first case having an inlet and a flange of a second case having an outlet, and an adsorption sheet for adsorbing evaporated fuel gas is attached to the downstream side of the air flow of the filter medium. With this air cleaner, the filter and adsorption sheet can be easily assembled to the air cleaner case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-231387 Summary of the Invention [Problem to be solved by the invention]

[0005] In the air cleaner of Patent Document 1, the flanges of the first case and the second case are provided so as to protrude outward from the wall surface of the case. In the rest of this specification, this type of flange provision method will be referred to as the "external flange type." In an air cleaner with external flange provision such as that described in Patent Document 1, the flanges protrude outward beyond the wall surface of the air cleaner case.

[0006] In recent years, there have been increasing restrictions on the space available for installing air cleaners, especially in vehicles. One reason for this is the increasing number of complex systems / engines installed in vehicles, such as hybrid vehicle motor generators, batteries, and power supply systems. Air cleaners must be installed away from other parts and components that are placed nearby. At the same time, it is desirable to make the capacity of the air cleaner as large as possible in order to regulate the air flow through the air cleaner and improve the sound deadening of the intake path through which the air flows.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide an air cleaner that can be easily increased in capacity, and another object of the present invention is to effectively increase the rigidity of the flange. [Means for solving the problem]

[0008] After extensive research, the inventors noticed that in conventional external flange type air cleaners, the case wall is only provided at a predetermined distance inward from the outer edge of the flange. Then, a flange is provided inward from the end of the case wall, and a guide wall is provided in a U-shape from the inner edge of the flange. The case wall and the guide wall are connected to each other by ribs. This led to the discovery that the capacity of the air cleaner can be increased, and the present invention was completed.

[0009] The present invention relates to an air cleaner having a first case, a second case, and a flat filter element, the filter element being sandwiched between the first case and the second case, and air passing through the air cleaner being filtered by the filter element, the filter element having an annular seal portion on its periphery, and at least the first case being provided with an annular flange portion that abuts against the seal portion, the flange portion being provided in at least a partial section of the periphery of the first case so as to extend from an end of the case wall toward the inside of the case along the extension direction of the flat filter element, and a guide wall being provided from an end of the flange portion on the inside of the case along a direction perpendicular to the extension direction of the flat filter element, and so that the cross section of the case wall, flange portion, and guide wall is configured to be approximately U-shaped. The case wall and the guide wall are connected to each other by ribs. This is an air cleaner (first invention).

[0010] In this specification, this type of flange arrangement, in which a flange is provided inward from the end of the case wall and a guide wall is further provided from the inner edge of the flange to form a U-shaped cross section, will be referred to as the "internal flange type."

[0011] In the first invention, preferably, the sealing portion has a polygonal shape when viewed in a direction perpendicular to the extension direction of the flat filter element, and the partial section is provided so as to extend beyond both corners of one side and reach at least a part of the adjacent side so as to form a substantially U-shape when viewed in a direction perpendicular to the extension direction of the flat filter element (second invention). Also, in the first invention, preferably, the section extends over the entire periphery when viewed in a direction perpendicular to the extension direction of the flat filter element (third invention). Also, in the first invention, preferably, the first case is formed by joining together a first case segment and a second case segment, which are formed in a shape obtained by dividing the first case at a dividing plane substantially parallel to the extension direction of the flat filter element (third invention). 4In the first invention, preferably, the width of the flange portion varies in the circumferential direction, and there is a portion where the width of the flange portion is larger than the width of the seal portion (the third invention). 5 invention). [Effects of the Invention]

[0012] According to the air cleaner of the present invention (first invention), the capacity of the air cleaner is increased. 5 In the case of the air cleaner of the present invention, the capacity of the air cleaner is particularly increased. Furthermore, when the air cleaner is configured as in the second or third aspect of the invention, the effect of effectively increasing the rigidity of the flange can be obtained. Also, 4 In the case of an air cleaner according to the present invention, such an air cleaner is easy to manufacture. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an exploded perspective view showing the configuration of an air cleaner according to a first embodiment. [Figure 2] 2 is a cross-sectional view of the periphery of a seal portion of the air cleaner of the first embodiment. FIG. [Figure 3] FIG. 2 is a cross-sectional view of a first case of the air cleaner of the first embodiment. [Figure 4] 2A and 2B are a plan view and a cross-sectional view of a first case of the air cleaner of the first embodiment. [Figure 5] 10A and 10B are a plan view and a cross-sectional view of a first case of an air cleaner according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, with reference to the drawings, an embodiment of the present invention will be described using an air cleaner that filters air supplied to an internal combustion engine of an automobile as an example. The present invention is not limited to the specific embodiment shown below, and the form can be modified and implemented.

[0015] FIG. 1 is an exploded perspective view showing the configuration of an air cleaner 10 according to the first embodiment. The air cleaner 10 has a first case 1, a second case 2, and a flat filter element 3. The filter element 3 is sandwiched between the first case 1 and the second case 2, and the internal space of the hollow box-shaped air cleaner case formed by the first case 1 and the second case 2 is divided by the flat filter element 3.

[0016] An inlet 5 is provided in the first case 1, and an outlet 6 is provided in the second case 2. An air cleaner 10 is provided in the intake path of an internal combustion engine, and duct members and the like that make up the intake path are connected to the inlet 5 and the outlet 6. Air flows into the air cleaner from the inlet 5 and flows out from the outlet 6. Air passing through the air cleaner 10 is filtered by the filter element 3. Although not essential, the first case 1 and the second case 2 are typically made of a thermoplastic resin (for example, polypropylene resin).

[0017] FIG. 2 is a cross-sectional view of the periphery of the seal portion 4 of the air cleaner 10 of the first embodiment. The flat filter element 3 has an annular seal 4 on its periphery. The seal 4 prevents unfiltered air from entering and passing through the air cleaner. The seal 4 is made of rubber, foamed resin, nonwoven fabric, or the like. In this embodiment, the filter element 3 is configured by integrating a pleated nonwoven fabric filter material 31 with a synthetic resin frame 32. The filter material is not limited to nonwoven fabric, and may be filter paper, foamed resin (sponge), or the like. In this embodiment, a flange-shaped protruding portion is provided on the periphery of the frame 32, and the rubber seal 4 is integrated with this portion.

[0018] An annular seal portion 4 is sandwiched between a first case 1 and a second case 2. At least the first case is provided with an annular flange portion 12 that abuts against the seal portion 4. Although not essential, in this embodiment, the second case 2 is also provided with an annular flange portion 22 that abuts against the seal portion 4. The annular seal portion 4 is sandwiched between the flange portions 12, 22 of the respective cases, and a seal is formed between the seal portion 4 and the flange portions 12, 22. The annular seal portion 4 may be provided so that its overall shape is rectangular or oblong as in this embodiment, but may also be other shapes such as a polygonal shape, a circle, an ellipse, or an oval shape.

[0019] In this embodiment, both the first case 1 and the second case 2 have flanges 12, 22, but this is not essential. Typically, a flange is provided on the downstream case (second case 2 in this embodiment), which is the so-called clean side, and a seal is achieved between the flange 22 of the downstream case and the seal portion 4. In this embodiment, the flange 12 of the first case 1 may be an inner flange type, which will be described later, and the flange 22 of the second case 2 is an outer flange type, but the flange 22 of the second case 2 may also be an inner flange type.

[0020] In the air cleaner 10 of the first embodiment, the flange portion 12 of the first case 1 is provided with the structure described below. The structure of the flange portion 12 of the first case 1 will be described below. Figure 3 is a cross-sectional view of the first case 1 of the air cleaner 10 of the first embodiment.

[0021] In the first case 1, a flange portion 12 is provided so as to extend from an end 11a of the case wall 11 toward the inside of the case along the extension direction of the flat filter element. The flange portion 12 and the seal portion 4 abut against each other to form a seal. Here, the case wall 11 is a wall that separates the internal space of the air cleaner 10 from the external space. The case wall 11 is formed in an open box shape with an open portion where the filter element 3 is attached, and the portion corresponding to the open edge is the end 11a of the case wall 11. The extension direction of the flat filter element also refers to the direction along the plane in which the seal portion 4 extends annularly, and in Figures 2 and 3, it is the left-right direction of the figures and the direction into the paper.

[0022] The flange portion 12 is provided with a width that allows it to abut against the seal portion 4 and properly seal. The width of the flange portion 12 may be constant in the circumferential direction, or it may vary. The portion of the flange portion 12 that abuts against the seal portion 4 may be flat, or may have grooves or protrusions along the circumferential direction as appropriate.

[0023] Furthermore, a guide wall 13 is provided substantially parallel to the case wall 11 from an end 13a of the flange portion 12 on the inside of the case along a direction perpendicular to the extension direction of the flat filter element. Here, the direction perpendicular to the extension direction of the flat filter element is the up-and-down direction in Figures 2 and 3. The guide wall 13 may be provided in a form that positions the filter element 3 or prevents it from falling off, or may be provided in a form that serves as an air guide plate.

[0024] 2 and 3, case wall 11, flange portion 12, and guide wall 13 are configured so that their cross sections are substantially U-shaped. That is, guide wall 13 is provided so as to extend from end 13a of flange portion 12 on the case inner side toward the rear side of first case 1.

[0025] In the following of this specification, this configuration in which the flange portion 12 extends from the end 11a of the case wall 11 toward the inside of the case, the guide wall 13 is provided from the inner end 13a of the flange portion 12, and the case wall, flange portion, and guide wall form a U-shaped cross section will be referred to as the ``internal flange type.''

[0026] In the air cleaner 10 of the first embodiment, the flange portion 12 and the guide wall 13 are provided in the above-mentioned inner flange type configuration along at least a partial section of the periphery of the first case 1. Although not essential, it is preferable that, as in the air cleaner 10 of the present embodiment, the section extends over the entire circumference when viewed in a direction perpendicular to the extension direction of the flat filter element, that is, that the inner flange type configuration be provided along the entire circumference of the annular seal portion 4 and flange portion 12. Furthermore, although not essential, it is preferable that, in both the first case and the second case, the flange portion 12 and the guide wall 13 are provided in the above-mentioned inner flange type configuration along at least a partial section of the periphery of each case.

[0027] Furthermore, although not essential, in the air cleaner 10 of the first embodiment, the case wall 11 and the guide wall 13 are connected to each other by ribs 14, 14. As shown in Fig. 3, it is particularly preferable that the ribs 14, 14 are provided so as to extend substantially perpendicular to the case wall 11 and the guide wall 13, in the up-and-down direction in Fig. 3.

[0028] Although not essential, in the air cleaner 10 of the first embodiment, the first case 1 is formed by assembling two divided bodies 1A, 1B. That is, the first case divided body 1A and the second case divided body 1B are formed in advance, each formed by dividing the first case 1 at a dividing plane P that is approximately parallel to the extension direction of the flat filter element, and then the first case divided body 1A and the second case divided body 1B are joined together to form the first case 1. Note that the dividing plane P does not need to be strictly parallel to the extension direction of the flat filter element, as long as it is roughly aligned with the extension direction. Furthermore, the dividing plane P may be a flat surface, but it may also be a cylindrical surface or a bent surface.

[0029] The air cleaner 10 of the first embodiment can be manufactured by applying a known manufacturing method. The filter element 3 and the seal portion 4 are manufactured and assembled by known manufacturing methods. The first case 1 and the second case 2 are typically manufactured by injection molding of a thermoplastic resin. To integrally mold the flange portion 12 and the guide wall 13 with the case wall 11, a slide mold, a holder, or the like may be used as appropriate.

[0030] Furthermore, in the case of air cleaner 10 of this embodiment, where the first case is configured by joining together first case segment 1A and second case segment 1B, first segment 1A and second case segment 1B may be manufactured by injection molding of thermoplastic resin, and then these may be joined together by welding (for example, hot plate welding or vibration welding) to manufacture first case 1. The segments may be joined together using adhesives, pressure-sensitive adhesives, or a locking structure (snap fit), etc.

[0031] The air cleaner 10 is completed by assembling the obtained first case 1 and second case 2 so that the filter element 3 is sandwiched between them. The first case 1 and second case 2 are closed together using fastening members such as bolts 8, 8 and nuts 81, 81, clip members (not shown), locking members, bands, etc., so that the filter element 3 and seal portion 4 are securely sandwiched between the first case 1 and second case 2. Note that mounting holes, bearing surfaces, nuts, etc. associated with the bolts 8, 8 are omitted from Figures 1 to 3.

[0032] The operation and effects of the air cleaner 10 of the first embodiment will be described. According to the air cleaner 10, the flange portion 12 and guide wall 13 are provided in an internal flange format in at least a portion of the periphery of the first case 1. In other words, the flange portion 12 is provided so as to extend from the end 11a of the case wall 11 toward the inside of the case along the extension direction of the flat filter element 3, and the guide wall 13 is provided from the end 13a on the inside of the case of the flange portion 12 along a direction perpendicular to the extension direction of the flat filter element 3, approximately parallel to the case wall 11. The cross section of the case wall 11, flange portion 12, and guide wall 13 is configured to be approximately U-shaped, and the capacity of the air cleaner is increased.

[0033] In conventional air cleaners such as those described in Patent Document 1, the flange is provided as an outer flange, so the case wall is erected inward from the flange, and even if the flange is provided as far outward as possible, the case wall would be positioned inside the case by the width of the flange that should abut against the seal, which inevitably reduces the capacity of the air cleaner. A reduction in air cleaner capacity is likely to lead to reduced sound deadening performance, worsening air flow resistance, and reduced filtering performance.

[0034] According to the air cleaner 10 of the first embodiment, in the section having the inner flange structure, the case wall 11 can be arranged outside the flange portion 12, and the capacity of the air cleaner can be increased. Furthermore, from the viewpoint of ease of manufacture, the filter material 31 portion of the flat filter element 3 is often formed in a rectangular shape (rectangular parallelepiped), and therefore the sealing portion 4 is also often provided in a rectangular shape when viewed in a direction perpendicular to the extension direction of the flat filter element. In this case, in conventional external flange-type air cleaners, the position of the case wall and the air cleaner capacity are restricted by the shape of the inside of the flange portion corresponding to the rectangular seal portion. On the other hand, with the air cleaner 10 of the first embodiment, only the position of the guide wall 13 is restricted by the rectangular seal portion, and the width of the flange portion 12 and the position of the case wall 11 are not restricted by the rectangular seal portion 4. In other words, without being restricted by the shape of the seal portion, the case wall can be provided to protrude to the maximum extent permitted by the surrounding layout, contributing to an increase in the capacity of the air cleaner.

[0035] Furthermore, in the air cleaner 10 of the first embodiment, the cross sections of the case wall 11, flange portion 12, and guide wall 13 are configured to have an approximately U-shaped cross section, which prevents the flange portion 12 from elastically deforming in a direction perpendicular to the extension direction of the flat filter element 3, thereby contributing to improved sealing performance.

[0036] In particular, as in the air cleaner 10 of the first embodiment, when viewed in a direction perpendicular to the extension direction of the flat filter element 3, the section in which the flange portion is provided in an inner flange format extends over the entire circumference, the guide wall 13 is provided in a cylindrical shape that is continuous in the circumferential direction, and the case wall 11, flange portion 12, and guide wall 13 function like an integrated shell structure, more effectively suppressing elastic deformation of the flange portion 12 in the direction perpendicular to the extension direction of the flat filter element 3. In other words, the rigidity of the flange is effectively increased.

[0037] Furthermore, although not essential, particularly when the case wall 11 and the guide wall 13 are connected to each other by ribs 14, as in the air cleaner 10 of the first embodiment, the case wall 11 and the guide wall 13 are more reliably prevented from relative displacement in a direction perpendicular to the extension direction of the flat filter element, thereby more effectively suppressing elastic deformation of the flange portion 12 and particularly effectively increasing the rigidity of the flange.

[0038] Furthermore, although not essential, if the first case 1, which has an internal flange-type flange portion 12, as in the air cleaner 10 of the first embodiment, is formed by joining together a first case segment 1A and a second case segment 1B formed in a shape obtained by dividing the first case 1 at a dividing plane P that is approximately parallel to the extension direction of the flat filter element 3, the structure of the mold used to manufacture the first case segment 1A and the second case segment 1B by injection molding of thermoplastic resin becomes simpler, making it easier to manufacture the air cleaner 10.

[0039] The invention is not limited to the above-described embodiment, and various modifications can be made to the invention. Other embodiments of the invention will be described below, focusing on differences from the above-described embodiment, and detailed descriptions of similarities will be omitted. Furthermore, these embodiments can be implemented by combining parts of them with each other or by substituting parts of them.

[0040] 4 is a plan view and a cross-sectional view of the first case 1 of the air cleaner 10 of the first embodiment. In the air cleaner 10 of the first embodiment, as shown in FIG. 4, the case wall 11, flange portion 12, and guide wall 13 are provided in the inner flange structure around the entire periphery of the flange portion 12. However, this is not essential, and the inner flange structure may be provided in at least a partial section of the periphery of the first case 1.

[0041] FIG. 5 shows a plan view and a cross-sectional view of a first case 21 of an air cleaner according to a second embodiment. In the first case 21 of the second embodiment, three of the four sides surrounding a rectangular filter element have an inner flange structure, and the remaining side has an outer flange structure. That is, the side 12x located on the left in the front view (upper left) of FIG. 5 has an outer flange structure in which a case wall 211 is connected to the inside of a flange portion 212 and a guide wall 213 is connected to the outside of the flange portion 212. Furthermore, the sides 12a, 12b, and 12c located on the right, upper, and lower sides in the front view of FIG. 5 have an inner flange structure in which a case wall 211 is connected to the outside of a flange portion 212 and a guide wall 213 is connected to the inside of the flange portion 212.

[0042] Even in the air cleaner of the second embodiment, in the portion having the inner flange structure, the case wall 211 of the first case 21 is disposed further outward, thereby increasing the capacity of the air cleaner.

[0043] Furthermore, in a portion having an internal flange structure, such as the air cleaner of this embodiment, it is preferable to provide a portion in which the flange width W is larger than the width W0 of the seal portion 4. In particular, it is preferable that the flange width W is at least twice the width W0 of the seal portion 4, and it is particularly preferable that it is at least three times the width W0. A larger width W can further increase the capacity. Furthermore, the flange width W may be constant in the circumferential direction, as in the embodiment shown in FIG. 4, or it may vary in width in the circumferential direction, as in the second embodiment shown in FIG. 5. With this configuration, the flange portion 212 and the case wall 211 can be provided in a form that protrudes toward the outside of the case, rather than the shape of the seal portion which is easily restricted by the shape of the filter element, and the capacity of the air cleaner can be further increased.

[0044] Furthermore, from the viewpoint of increasing the rigidity of the flange portion, it is preferable that the sealing portion has a polygonal shape (particularly, but not limited to, a rectangular shape) when viewed in a direction perpendicular to the extension direction of the flat filter element, and that the section where the flange portion has an internal flange structure has a substantially U-shape when viewed in a direction perpendicular to the extension direction of the flat filter element, that is, is provided so as to extend beyond the corners at both ends of one side and reach at least a part of the adjacent side, as in the second embodiment shown in Fig. 5. That is, in the embodiment of Fig. 5, the substantially U-shaped section that spans three sides, the upper side 12b, the right side 12a, and the lower side 12c that surround the rectangular filter element has an internal flange structure, and as a result, the section with the internal flange structure is provided so as to extend beyond the corners at both ends (upper end 12d and lower end 12e) of the right side 12a and reach a part of the adjacent sides 12b and 12c.

[0045] With this structure, the guide wall 213 and the case wall 211 with an inner flange and U-shaped cross section are provided continuously in a cylindrical shape on the right side 12a, the upper side 12b, and the lower side 12c, and the case wall 211, the flange portion 212, and the guide wall 213 function as an integrated shell structure, more effectively preventing elastic deformation of the flange portion 212 in the direction perpendicular to the extension direction of the flat filter element 3. In other words, the rigidity of the flange is effectively increased.

[0046] Furthermore, in the description of the air cleaner 10 of the first embodiment, an example was shown in which the flange portion 12 of the first case 1 is an inner flange type and the flange portion 22 of the second case 2 is an outer flange type. However, an embodiment in which both the first case 1 and the second case 2 are inner flange type flanges may also be used. If either the first case 1 or the second case 2 has an inner flange type flange portion or a guide wall along the entire circumference or along a portion of the circumference of the flange portion, the effect of increasing capacity can be obtained. Furthermore, in the description of the air cleaner 10 of the first embodiment, an example was shown in which the inlet 5 is provided in the first case 1 and the side of the first case 1 is the dust side. However, the case on the clean side may also be considered the first case.

[0047] In the description of the above embodiment, detailed explanations of the air cleaner's details, such as the case opening and closing structure, and the mounting and fixing structure, have been omitted, but for these, structures in the prior art may be used.

[0048] Furthermore, a silencer such as a resonator may be integrated into the air cleaner of the above embodiment to form a so-called modular air cleaner. The air cleaner may also be provided with an air flow sensor, a fuel vapor adsorption filter, a blow-by passage, and the like, as appropriate.

[0049] The air cleaner of the above embodiment can be applied to technical fields other than the intake system of the exemplified internal combustion engine. That is, the air cleaner may be an air cleaner for filtering air supplied to an engine or power plant other than an internal combustion engine (for example, a jet engine, a steam engine, or a fuel cell), an air cleaner for filtering cooling air for cooling a battery, or an air cleaner for filtering air passing through an air conditioner or a ventilation system. [Industrial Applicability]

[0050] The air cleaner of the above embodiment can be used in the intake system of an internal combustion engine, for example, and is highly industrially useful as it can improve space efficiency. [Explanation of symbols]

[0051] 10 Air cleaner 1. Case 1 1A Case 1st division 1B Second case section 11 Case Wall 12 Flange 13 Guide Wall 14 Ribs 2. Case 2 22 Flange 3 filter elements 31 Filter material 32 Frame 4 Seal part 8 volts

Claims

1. an air cleaner having a first case, a second case, and a flat filter element, the filter element being sandwiched between the first case and the second case, and air passing through the air cleaner being filtered by the filter element; the filter element having an annular seal portion on its periphery, and at least the first case having an annular flange portion that abuts against the seal portion, the flange portion being provided in at least a partial section of the periphery of the first case so as to extend from an end of the case wall toward the inside of the case along the extension direction of the flat filter element; and a guide wall being provided from an end of the flange portion on the inside of the case along a direction perpendicular to the extension direction of the flat filter element, and being generally parallel to the case wall, so that the cross section of the case wall, the flange portion, and the guide wall is generally U-shaped, and the case wall and the guide wall are connected to each other by a rib.

2. The sealing portion has a polygonal shape when viewed in a direction perpendicular to the extending direction of the flat filter element, The partial section is provided so as to extend beyond corners at both ends of one side and reach at least a part of an adjacent side, so as to form a substantially U-shape when viewed in a direction perpendicular to the extension direction of the flat filter element.

2. The air cleaner according to claim 1.

3. When viewed along a direction perpendicular to the extending direction of the flat filter element, The section extends over the entire circumference.

2. The air cleaner according to claim 1.

4. The first case is The filter element is configured by joining together a first case divided body and a second case divided body, the first case divided body being formed in a shape obtained by dividing the first case along a dividing plane substantially parallel to the extending direction of the flat filter element.

2. The air cleaner according to claim 1.

5. The width of the flange portion varies in the circumferential direction, and there is a portion where the width of the flange portion is larger than the width of the seal portion.

2. The air cleaner according to claim 1.

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