JP2011025157A - Air filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To press and fix a filter unit to a mounting frame with a simple structure. <P>SOLUTION: An air filter 10 includes the filter unit 11 comprising first and second filter portions 41, 42, the mounting frame 13, a flange portion 14 formed so as to project inside from the mounting frame 13, a mounting member 15, and a gasket mounted to the front side of the filter unit 11. The mounting member 15 is formed in an L shape by a shaft portion 70 pivotally supported on the inside surface of the mounting frame 13 and a holding portion 71 rotatable around the shaft portion 70. The holding portion 71 is disposed at a position pressing the filter unit 11 from the back side thereof by rotating around the shaft portion 70, thereby pressing and fixing the filter unit 11 to the flange portion 14 through the gasket. The mounting member 15 is pivotally supported to the mounting frame 13 by repulsion from the gasket so as to restrict the movement toward the back side. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an air filter in which an air filter unit is attached to an attachment frame unit by being pressed by a pressing portion from the back side.

  In order to remove dust and contaminants in the air, an air filter unit in which a filter medium pack is disposed inside a square frame filter frame is widely used. The air filter unit is usually installed in various facilities in a state of being housed inside the mounting frame. Conventionally, an air filter unit may be stored inside a mounting frame in a state where the air filter unit is pressed forward from the back side by a fixture and pressed against a flange portion projecting inward from the mounting frame (for example, Patent Document 1).

  In Patent Document 1, the fixture includes a shaft portion that is supported by the bearing on the inner surface of the mounting frame, and a pressing portion that projects at a right angle from the tip portion of the shaft portion and presses the filter unit from the back side. Become. The fixture is rotatable about the shaft portion, is movable in the axial direction along the bearing, and is biased forward by a wire spring. Such a fixture can press the filter unit forward by a pressing part biased by a wire spring by pulling the pressing part to the back side along the axial direction and then turning it inside to release it. Is possible.

JP 2006-159107 A

  However, in the air filter disclosed in Patent Document 1, a wire spring is required to urge the fixture, so that the mounting structure is complicated. Further, the pressing portion that presses the filter unit easily rotates about the shaft portion due to vibration or the like, and therefore, the filter unit may be unexpectedly detached from the mounting frame.

  Therefore, the present invention has been made in view of the above problems, and the filter unit can be fixed to the mounting frame with a simple configuration, and the filter unit is detached from the mounting frame by vibration or the like. An object of the present invention is to provide an air filter that prevents the above.

  An air filter according to the present invention is formed by a rectangular frame-shaped mounting frame opened in the front-rear direction, a filter unit at least a part of which is disposed inside the mounting frame, and an inward projecting from the mounting frame. The flange part arrange | positioned ahead of this, an attachment member, and a control part are provided. The mounting member is integrally formed by a shaft portion that is pivotally supported on the inner surface of the mounting frame and extends in the front-rear direction, and a pressing portion that is connected to the shaft portion and is rotatable about the shaft portion. The portion is arranged at a position where the filter unit is pressed from the back side by rotating around the shaft portion, and presses and fixes the filter unit to the flange portion. The restriction member restricts the mounting member that presses the filter unit from moving backward due to the reaction force.

  The air filter may be attached to the front surface of the filter unit and provided with a gasket formed of an elastic material, and the filter unit may be pressed and fixed to the flange portion via the gasket.

  It is preferable that a protrusion is formed on the outer periphery of the shaft portion and that the attachment member is restricted from moving in the axial direction by engaging the protrusion with the restricting portion. For example, a bearing portion in which a shaft portion is disposed inside is provided on the inner surface of the mounting frame. For example, the bearing portion is formed with an opening into which the protrusion is inserted, and the edge of the opening serves as the restriction portion.

  For example, the mounting frame includes a pair of horizontal plate portions facing each other and a pair of vertical plate portions facing each other, and the shaft portion is pivotally supported on the inner surface of the horizontal plate portion.

  It is better that the pressing portion is regulated by the regulating portion so as to be rotated within a predetermined range. At this time, it is preferable that the pressing portion is regulated so as to be rotated in a range from a first position where the filter unit is not pressed to a second position where the filter unit is pressed. The second position is preferably a position further rotated from a position where the pressing portion is arranged in parallel to the vertical plate portion. Moreover, it is preferable that the 1st position is a position further rotated to the outer side of the attachment frame from the position where a pressing part is arrange | positioned in parallel with a horizontal plate part. For example, when the protrusion is formed on the outer periphery of the shaft portion, the rotation of the pressing portion is restricted by engaging the protrusion with the restricting portion.

  The angle formed by the shaft portion and the pressing portion is preferably larger than 90 °, that is, the pressing portion is preferably inclined obliquely rearward with respect to the shaft portion. The shaft portion and the pressing portion are, for example, integrally formed to constitute an L-shaped bar member. It is preferable that the restricting portion restricts the mounting member so that it cannot substantially move in the axial direction. The filter unit includes, for example, a first filter unit and a second filter unit superimposed on the back surface of the first filter.

  In the present invention, it is possible to press and fix the filter unit to the mounting frame with a simple configuration without using parts such as a spring.

It is a perspective view showing an air filter concerning one embodiment of the present invention. It is a disassembled perspective view which shows the air filter which concerns on one Embodiment of this invention. It is a perspective view which shows an attachment frame unit from the front side. It is a fragmentary perspective view for showing the attachment structure of an air filter. It is a perspective view for showing an attachment member and a backing plate. It is arrow sectional drawing in the VI-VI line of FIG. It is arrow sectional drawing in the VI-VI line of FIG. 4, Comprising: It is a figure for showing a mode when a holding | suppressing part is rotated outside the attachment frame. It is a partial front view of an air filter, Comprising: It is a figure for showing a behavior when a pressing part rotates. It is the top view which looked at the air filter from upper direction, Comprising: It is the figure which abbreviate | omitted and showed the upper vertical board part.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, the air filter 10 includes a filter unit 11, a mounting frame unit 12, a mounting member 15, and a contact plate 16.

  The mounting frame unit 12 includes a mounting frame 13 that has a square frame shape opened in the front-rear direction, and a flange portion 14 that covers a part of the opening on the front side of the mounting frame 13. The mounting frame 13 includes a left horizontal plate portion 23 and a right horizontal plate portion 24 that face each other, and an upper vertical plate portion 25 and a lower vertical plate portion 26 that face each other and connect the end portions of the horizontal plate portions 23 and 24. Prepare. The horizontal plate portions 23 and 24 have a substantially rectangular plate shape that is long in the vertical direction, and the vertical plate portions 25 and 26 have a substantially rectangular plate shape that is long in the left-right direction.

  In the present specification, the direction perpendicular to the horizontal plate portions 23 and 24 and the direction in which the horizontal plate portions 23 and 24 face each other is the left-right direction, the direction perpendicular to the vertical plate portions 25 and 26, and the vertical direction. A direction in which the plate portions 25 and 26 face each other will be described as an up-down direction. The left-right direction is a direction orthogonal to the up-down direction, and the front-rear direction is a direction orthogonal to the up-down direction and the left-right direction. Air is passed through the air filter 10 from the rear side (front side of the paper) to the front side (back side of the paper).

  As shown in FIGS. 1 and 2, the filter unit 11 includes a first filter unit 41 made of, for example, a medium performance filter, and a second filter unit 42 made of a pre-filter. Each of the first and second filter portions 41 and 42 includes first and second filter frames 43 and 44 each having a rectangular frame shape slightly smaller than the mounting frame 13 in the vertical and horizontal directions, and the first and second filters. First and second filter media 45 and 46 disposed inside the frames 43 and 44, respectively.

  The first filter medium 45 is a filter medium pack formed by zigzagging a sheet-shaped filter medium made of glass fiber, synthetic fiber, nonwoven fabric, or the like. The second filter medium 46 constituting the prefilter has a mesh that is coarser than the first filter medium 45, removes coarse dust and contaminants in the air, and prevents them from adhering to the first filter medium 45.

  A part of the first filter frame 43 is disposed inside the mounting frame 13, and a part of the first filter frame 43 protrudes from an opening on the rear side of the mounting frame 13. The first filter frame 43 includes a left frame portion 53 and a right frame portion 54 that face each other in the left-right direction, and ends of the frame portions 53 and 54 that are opposed to each other in the vertical direction. 56. The frame portions 53 to 56 have a rectangular plate shape. The outer peripheral surfaces of the frame portions 53 to 56 are arranged in parallel to the inner surfaces of the plate portions 23 to 26 of the mounting frame 13, but there are gaps between the inner surfaces of the plate portions 23 to 26. is there.

  The second filter frame 44 is disposed outside the attachment frame 13. The second filter frame 44 connects the left frame portion 63 and the right frame portion 64 facing each other in the left-right direction and the ends of the frame portions 63 and 64, and the top frame portion 65 and the ground frame portion facing each other in the vertical direction. 66. The outer peripheral surfaces of the frame portions 63 to 66 are parallel to the inner surfaces of the plate portions 23 to 26 of the mounting frame 13. The second filter frame 44 has substantially the same size as the first filter frame 43, and the front surface thereof is in close contact with the back surface of the first filter frame 43. That is, the filter unit 11 is configured by overlapping the first and second filter portions 41 and 42, and the back surface of the filter unit 11 (second filter portion 42) is from the back surface of the mounting frame 13. Arranged on the rear side.

  As shown in FIG. 3, the front end portions of the plate portions 23 to 26 of the attachment frame 13 are perpendicular to the plate portions 23 to 26 and extend toward the inside of the attachment frame 13. 36 is continuously provided. The left end portion and the right end portion of the plate portions 35 and 36 are connected to the upper end portion and the lower end portion of the plate portions 33 and 34, whereby the plate portions 33 to 36 are integrated to form a square frame plate-shaped flange portion. 14 is formed. The entire circumference of the outer edge of the flange portion 14 is connected to the entire circumference of the front end of the mounting frame 13, and is disposed in front of the filter unit 11.

  The contact plate 16 is attached to the inner surfaces of the horizontal plate portions 23 and 24, and forms a bearing portion 80 together with the inner surfaces of the horizontal plate portions 23 and 24. Two backing plates 16 are attached to each of the horizontal plate portions 23 and 24, and are disposed in the vicinity of the upper end portion and the lower end portion of each of the horizontal plate portions 23 and 24. The attachment member 15 is provided corresponding to each bearing portion 80, and includes a shaft portion 70 inserted into the bearing portion 80 and a pressing portion 71 provided continuously to the shaft portion 70. The attachment member 15 is a member for pressing and fixing the filter unit 11 to the attachment frame unit 12 by the pressing portion 71.

  Next, the structures of the attachment member and the bearing portion will be described in more detail with reference to FIGS. 4 to 8 show a bearing portion and a mounting member provided in the vicinity of the upper end portion of the left lateral plate portion 23, and the structure thereof will be described below, but the structures of the other bearing portions and the mounting member are also the same. Therefore, the description thereof is omitted.

  As shown in FIGS. 4 and 5, the attachment member 15 is integrally formed by a shaft portion 70 extending in the front-rear direction and a pressing portion 71 extending obliquely rearward from the rear end 70 </ b> A of the shaft portion 70. It is the L-shaped rod-shaped member made. An angle R1 formed by the pressing portion 71 and the shaft portion 70 is an obtuse angle larger than 90 °, and is 91 to 105 °, for example, and preferably 95 to 105 ° when the gasket 17 described later is provided. However, when the gasket 17 is not provided, the angle R1 should be small, for example, preferably about 91 to 95 °. This is because when the gasket 17 is present, the filter unit 11 easily moves forward due to the pressing of the pressing portion 71, whereas when the gasket 17 is not provided, the filter unit 11 is difficult to move forward due to the pressing of the pressing portion 71. For example, the attachment member 15 is formed by bending a bar made of metal into an L shape, and the pressing portion 71 and the shaft portion 70 are each formed in a substantially cylindrical rod shape.

  The contact plate 16 is disposed along the inner surface of the horizontal plate portion 23 and is attached to the horizontal plate portion 23. A substantially central portion in the up-down direction of the contact plate 16 swells in a U shape toward the inside of the mounting frame 13 and is formed in the groove 83. The groove portion 83 extends in the front-rear direction, and is provided from one end to the other end in the front-rear direction of the contact plate 16. That is, the contact plate 16 includes first and second plate portions 81 and 82 that are in close contact with the inner surface of the horizontal plate portion 23, and a groove portion 83 that is formed therebetween. The inner peripheral surface of the groove 83 forms a cylindrical bearing portion 80 together with the inner surface of the horizontal plate portion 23.

  The front portion of the shaft portion 70 is disposed inside the bearing portion 80 and is supported by the bearing portion 80. In addition, the rear portion of the shaft portion 70 protrudes from the bearing portion 80, and the rear end 70 </ b> A of the shaft portion 70 is disposed further rearward than the back surface of the mounting frame 13. The pressing portion 71 can rotate around the shaft portion 70, and can be arranged behind the filter unit 11 (see FIG. 1) by rotating around the shaft portion 70.

  The shaft portion 70 is formed with a protrusion 72 protruding from the outer periphery thereof. The protrusion 72 is formed, for example, by pressing an L-shaped bar having a circular cross section. The protrusion 72 is sufficiently shorter than the pressing portion 71. 6 and 7, for example, the protrusion 72 protrudes in a direction different from the direction in which the pressing portion 71 extends from the shaft portion 70, but may protrude in the same direction.

  The groove portion 83 (that is, the bearing portion 80) is provided with an opening 84 through which the protrusion 72 is inserted. The opening 84 is provided in a midway portion 83 </ b> A in the front-rear direction of the groove 83. The length of the opening 84 in the front-rear direction is substantially equal to the length of the protrusion 72 in the front-rear direction. Therefore, the protrusion 72 is engaged with the front and rear edge portions of the opening 84 and is regulated so as not to move substantially in the front-rear direction (the axial direction of the shaft portion). The contact plate 16 is fixed to the horizontal plate portion 23 by spot welding or the like in a state where the shaft portion 70 is disposed inside the groove portion 83 and the projection 72 is inserted into the opening 84, for example.

  As shown in FIGS. 6 and 7, the inner peripheral surface of the groove portion 83 is formed along the outer periphery of the shaft portion 70, and the shaft portion 70 can rotate inside the groove portion 83. Thereby, as above-mentioned, the attachment member 15 (pressing part 71) can rotate centering | focusing on the axial part 70. As shown in FIG. In addition, a part of the middle part 83 </ b> A of the groove part 83 is cut out to be formed as the above-described opening 84, and a part is left as a piece part 85 extending from the second plate part 82.

  As shown in FIG. 6, rotation of the pressing portion 71 in one direction around the axis (clockwise in FIGS. 4 to 8) is caused by engagement of the protrusion 72 with the piece portion 85 (lower edge portion of the opening 84). Be regulated. When the protrusion 72 engages with the one piece 85, the pressing portion 71 is located at a position parallel to the vertical plate portions 25 and 26 (position of FIG. 8D; position parallel to the left-right direction when viewed from the back). Further, it is arranged at a position (FIG. 8E) rotated clockwise by R2 °.

  As shown in FIG. 7, the protrusion 72 is engaged with the first plate portion 81 (the upper edge of the opening 84) when the pressing portion 71 rotates in the other direction (counterclockwise in FIGS. 4 to 8). Be regulated by When the protrusion 72 is engaged with the first plate portion 81, the pressing portion 71 is in a position parallel to the horizontal plate portion 23 (position in FIG. 8B; position parallel to the vertical direction when viewed from the back). Is further arranged at a position rotated counterclockwise by R3 ° (FIG. 8A). The angles R2 and R3 are preferably about 10 to 15 °, for example.

  Thus, as shown in FIG. 8, the attachment member 15 (pressing portion 71) can rotate within the range of (A) to (E), and the protrusion 72 is the upper and lower edges of the opening 84. It is not possible to rotationally move out of the range by engaging the. The pressing portion 71 does not press the filter unit 11 when it is in the positions of FIGS. 8A and 8B, but contacts the back surface of the filter unit 11 when it is in the positions of FIGS. 8C to 8E. Then, the filter unit 11 is pressed forward.

  FIG. 9 is a top view showing a state where the filter unit 11 is pressed by the pressing portion 71. FIG. 9 shows a bearing portion and an attachment member provided in the vicinity of the upper end portion of the right horizontal plate portion 24.

  As shown in FIG. 9, the gasket 17 is attached to the front surface of the filter unit 11 (that is, the front surface of the first filter frame 43). The gasket 17 is formed of an elastic material such as rubber or sponge, and is formed in a square frame shape along the front surface of the first filter frame 43 having a square frame shape. Note that the thickness of the gasket 17 is, for example, about 5 mm. The gasket 17 is in close contact with the back surface of the flange portion 14, closes a gap between the flange portion 14 and the front surface of the first filter frame 43, and prevents air from leaking from these gaps.

  The pressing portion 71 is disposed behind the filter unit 11 by rotating around the shaft portion 70 and is brought into contact with the back surface of the filter unit 11 (that is, the back surface of the second filter frame 44). The pressing portion 71 arranged in this way presses the filter unit 11 (that is, the first and second filter frames 43 and 44) forward, whereby the filter unit 11 is interposed via the gasket 17. The flange part 14 is pressed and fixed.

  When the filter unit 11 is pressed by the pressing portion 71, a reaction force directed rearward is generated with respect to the pressing portion 71, but the attachment member 15 moves rearward in the axial direction by the reaction force. There is no. This is because the movement of the attachment member 15 in the axial direction (front-rear direction) is restricted by the engagement between the protrusion 72 and the edge of the opening 84 as described above.

  As is clear from FIG. 9, the rear end 70 </ b> A of the shaft portion 70 (that is, the connecting portion between the shaft portion 70 and the pressing portion 71) is disposed outside the outer peripheral surface of the second filter frame 44. Further, there is a gap 28 between the rear end 70 </ b> A of the shaft portion 70 and the outer peripheral surface of the second filter frame 44. The shaft portion 70 is disposed in parallel in the front-rear direction, and the pressing portion 71 extends obliquely rearward and inward from the shaft portion 70, so that the pressing portion 71 is located on the outer edge 42 </ b> A on the back surface of the second filter frame 44. Abuts but does not contact the rest of the back.

  The portion (contact portion 71B) that contacts the outer edge 42A of the pressing portion 71 changes while the pressing portion 71 is rotated from (C) to (E) in FIG. The contact portion 71B is closest to the rear end 70A when the pressing portion 71 is parallel to the vertical plate portions 25 and 26 (FIG. 8D). Here, the pressing portion 71 extends obliquely rearward from the rear end 70A, and the portion closer to the rear end 70A is located on the front side. Therefore, the contact portion 71B is located on the foremost side (position closest to the flange portion 14) in the state of FIG. 8D.

  That is, when the pressing portion 71 is rotated from (C) to (D) in FIG. 8, the compression amount of the gasket 17 and the pressing force against the filter unit 11 are gradually increased by the rotation. And the said pressing force and compression amount become the largest when the holding | suppressing part 71 will be in the state of (D). Moreover, if it further rotates from FIG. 8 (D) to (E), the said pressing force and compression amount will become gradually small again by the rotation.

  Thereby, in this embodiment, the reaction force from the filter unit 11 which acts on the holding | suppressing part 71 becomes smaller in the state of FIG.8 (E) than the state of FIG.8 (D). For this reason, in the present embodiment, the attachment member 15 is less likely to be rotated in the reverse direction (counterclockwise in FIG. 8) by being rotated to the state shown in FIG. This is because, in order to return to the state of FIG. 8D from FIG. 8E, it is necessary to rotate the pressing portion 71 in the reverse direction against the reaction force that gradually increases.

  Next, a method for assembling the air filter 10 in the present embodiment will be described. In the present embodiment, as is apparent from FIGS. 1 and 2, the first filter portion 41 is disposed inside the mounting frame 13 on the back side of the flange portion 14, and on the back surface of the first filter portion 41. The 2nd filter part 42 is piled up and arranged. At this time, the pressing portion 71 is in the state shown in FIG. As a result, when viewed from the back side, the pressing portion 71 is disposed at a position that does not overlap the filter unit 11, so that the filter portions 41 and 42 are placed on the back side of the flange portion 14 without being interrupted by the pressing portion 71. It is possible to arrange.

  Next, as shown in FIG. 6, the pressing portion 71 is rotated inside the mounting frame 13 until the protrusion 72 engages with the piece portion 85, and the state shown in FIG. Thereby, the holding part 71 presses and fixes the filter unit 11 to the flange part 14.

  As described above, in this embodiment, the filter unit can be pressed and fixed to the mounting frame without using an extra member such as a spring member and only by rotating the pressing portion, so that the air filter is assembled with a simple configuration. be able to. In addition, when the holding portion 71 is rotated from FIG. 8C to FIG. 8D by making the angle R1 larger than 90 °, the reaction force from the filter unit 11 is initially small and gradually increases. Even if the portion 71 is not rotated, the state shown in FIG.

  Further, since the pressing portion 71 is rotated to the state of FIG. 8E, it is difficult to rotate in the reverse direction (counterclockwise in FIG. 8) as described above. Therefore, it is prevented that the holding | suppressing part 71 reversely rotates by vibration etc. and it returns to the state (FIG. 8 (A) (B)) which does not press the filter unit 11. FIG. Furthermore, in this embodiment, even when the filter unit is composed of two filter units, these two filter units can be fixed with a simple configuration.

  Furthermore, since the gasket 17 that is compressed and deformed by the pressing force from the pressing portion 71 is provided on the front surface of the filter unit 11, the filter unit 11 largely moves forward by a relatively small pressing force. Therefore, the filter unit 11 can be stably pressed and fixed by rotating the mounting member 15 with a small force.

  However, in this embodiment, the gasket may be omitted. This is because even if there is no gasket, a reaction force directed rearward is applied to the pressing portion by the repulsive force of the first and second filter frames 41 and 43 and the flange portion 14.

  In the present embodiment, the bearing portion 80 is also provided in the vertical plate portions 25 and 26, and the filter unit may be pressed by an attachment member pivotally supported by the vertical plate portion. Further, the number of the bearing portions 80 provided on each of the plates 23 to 26 may be any number as long as it is one or more. Furthermore, the number of filter units constituting the filter unit is not limited as long as it is one or more.

DESCRIPTION OF SYMBOLS 10 Air filter 11 Filter unit 12 Mounting frame unit 13 Mounting frame 14 Flange part 15 Mounting member 16 Cover plate 17 Gasket 70 Shaft part 71 Holding part 72 Protrusion 80 Bearing part 83 Groove part 84 Opening

Claims (14)

A square frame-shaped mounting frame opened in the front-rear direction;
A filter unit at least a part of which is disposed inside the mounting frame;
A flange portion that is formed to project inward from the mounting frame and is disposed in front of the filter unit;
The pressing portion is integrally formed by a shaft portion that is pivotally supported on the inner surface of the mounting frame and extends in the front-rear direction, and a pressing portion that is connected to the shaft portion and is rotatable about the shaft portion. However, by rotating about the shaft portion, the mounting unit is disposed at a position to press the filter unit from the back side, and presses and fixes the filter unit to the flange portion,
An air filter provided with the control part which controls that the attachment member which presses the filter unit moves back by reaction force.   The air filter according to claim 1, wherein an angle formed by the shaft portion and the pressing portion is larger than 90 °.   The protrusion is formed on an outer periphery of the shaft portion, and the attachment member is restricted from moving in the axial direction by being engaged with the restricting portion. The air filter according to 1.   A bearing portion in which the shaft portion is disposed is provided on the inner surface of the mounting frame, and an opening into which the protrusion is inserted is formed in the bearing portion, and the restriction portion is an edge portion of the opening. The air filter according to claim 3, wherein the air filter is provided.   The air filter according to claim 1, wherein the pressing portion is regulated so as to be rotated within a predetermined range by the regulating portion.   The said holding | suppressing part is controlled so that it may rotate in the range from the 1st position which does not press the said filter unit to the 2nd position which presses the said filter unit. Air filter.   The mounting frame includes a pair of horizontal plate portions facing each other and a pair of vertical plate portions facing each other, the shaft portion is pivotally supported on the inner surface of the horizontal plate portion, and the second position is The air filter according to claim 6, wherein the pressing portion is a position further rotated from a position where the pressing portion is arranged in parallel to the vertical plate portion.   The mounting frame includes a pair of horizontal plate portions facing each other and a pair of vertical plate portions facing each other, the shaft portion is provided on an inner surface of the horizontal plate portion, and the first position is The air filter according to claim 6, wherein the pressing portion is a position further rotated to the outside of the attachment frame from a position where the pressing portion is arranged in parallel to the horizontal plate portion.   6. The air according to claim 5, wherein a protrusion is formed on an outer periphery of the shaft portion, and the rotation of the pressing portion is restricted by engaging the protrusion with the restricting portion. filter.   A bearing portion in which the shaft portion is disposed is provided on the inner surface of the mounting frame, and an opening into which the protrusion is inserted is formed in the bearing portion, and the restriction portion is an edge portion of the opening. The air filter according to claim 9, wherein:   The air filter according to claim 1, further comprising: a gasket attached to a front surface of the filter unit and formed of an elastic material, wherein the filter unit is pressed and fixed to the flange portion via the gasket.   The air filter according to claim 1, wherein the shaft portion and the pressing portion are integrally formed to constitute an L-shaped bar member.   The air filter according to claim 1, wherein the restricting portion restricts the attachment member so that the attaching member cannot substantially move in an axial direction.   The air filter according to claim 1, wherein the filter unit includes a first filter unit and a second filter unit superimposed on a back surface of the first filter.

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