Filter Unit

Abstract

To provide a filter unit capable of suppressing a decrease in air purification function by reducing deformation. [Solution] The filter unit is a filter (60) having an accordion-like shape and includes a first section (6U), a second section (6F), and a third section (6S). The second section (6F) and the third section (6S) face each other in the front-rear direction below the first section (6U). The filter unit further includes first shape-retaining members provided at both left-right ends of the filter (60) to maintain the shape of the filter (60), and second shape-retaining members (7) provided at least on a second tip section (65F) at the bottom end of the second section (6F) and a third tip section (65S) at the bottom end of the third section (6S), excluding both left-right ends, to maintain the shape of the filter (60).

Description

[Technical Field]

[0001] The present invention relates to a filter unit used in an air purifier. [Background technology]

[0002] Patent Document 1 discloses an air purifier and a filter. The air purifier uses a fan to draw in air. The drawn-in air is purified by passing through a filter inside the air purifier and then discharged. The filter is a bellows-folded HEPA filter folded in two places to form a U-shape and placed inside the air purifier. The filter is provided with stop frames at both ends of the filter in the direction in which the bellows folds extend (hereinafter referred to as the fold direction) to prevent the bellows folds from widening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3829105 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned filter may have both ends perpendicular to the fold direction that may curl up during use, which may cause the shape of the filter to change and reduce its air purification function.

[0005] An object of the present invention is to provide a filter unit that can reduce deformation and suppress a decrease in the air purification function. [Means for solving the problem]

[0006] A filter unit according to the present invention is a filter having an accordion-folded shape, and includes a first part, a second part extending from an end of the first part on one side in a first direction to one side in a second direction intersecting with the first direction, and a third part extending from an end of the first part on the other side in the first direction to one side in a third direction intersecting with the first direction, before The filter has a fold direction, which is the direction in which the accordion-folded folds of the first part, the second part, and the third part extend, that is perpendicular to the first direction, the second direction, and the third direction; and first shape-retaining members, which are provided at both ends of the filter in the fold direction and which retain the shape of the filter; a second shape-retaining member disposed at a second tip portion, which is an end portion on one side in the cross direction of the second portion, and a third tip portion, which is an end portion on one side in the cross direction of the third portion, and extending in the fold direction; The present invention is characterized by the following.

[0007] The filter unit has second shape-retaining members for retaining the shape of the filter at second and third tip portions corresponding to the ends of the filter in a direction perpendicular to the accordion-folded fold direction. This reduces the possibility that the filter unit's both ends in a direction perpendicular to the fold direction will be rolled up during use, thereby preventing deformation of the filter and suppressing a decrease in the air purification function. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of an air purifier 1A. [Figure 2] FIG. 2 is a plan view of the air purifier 1A. [Figure 3] FIG. 2 is a perspective view of the air purifier 1A with the lid 31 removed. [Figure 4] 3 is a cross-sectional view taken along line AA in FIG. 2, viewed from the direction of the arrow. [Figure 5] 3 is a cross-sectional view taken along line BB in FIG. 2, viewed from the direction of the arrow, and an enlarged view of a portion of the cross-sectional view. [Figure 6] FIG. 2 is an exploded perspective view of the air purifier 1A. [Figure 7] FIG. 2 is a view showing second shape-retaining members 7A to 7D. [Figure 8] FIG. 10 is a diagram showing second shape-retaining members 7E to 7H. [Figure 9] FIG. 10 is a view showing second shape-retaining members 7I and 7J. [Figure 10] 10A and 10B are diagrams showing second shape-retaining members 7K and 7L. [Figure 11] FIG. 10 is a view showing second shape-retaining members 7M and 7N. [Figure 12] FIG. 2 is a perspective view of an air purifier 1B. DETAILED DESCRIPTION OF THE INVENTION

[0009] An air purifier 1A and a filter unit 6 according to one embodiment of the present invention will now be described. 1 correspond to the upper, lower, right, left, lower left, and upper right sides of the air purifier 1A, respectively. The upper, lower, lower right, upper left, lower left, and upper right sides of the filter unit 6, respectively.

[0010] Air purifier 1A draws in ambient air. The air drawn in is purified by passing through filter unit 6 attached to air purifier 1A. The purified air is blown out from air purifier 1A to the outside.

[0011] Air purifier 1A includes a housing 2 (see Figures 1 to 3), a lid 31 (see Figures 1 and 2), fans 5L and 5R (collectively referred to as "fans 5"; see Figures 4 and 6), and a control board 9 (see Figure 6).

[0012] <Case 2> As shown in FIGS. 1 to 3, the housing 2 has a substantially hexahedral shape, more specifically, a substantially rectangular parallelepiped shape elongated in the left-right direction. The housing 2 has a base 3B (see FIGS. 1 and 3), a front wall 3F, a rear wall 3S, a left wall 3L, a right wall 3R (see FIGS. 2 and 3), and a top wall 3U. The base 3B is substantially box-shaped, and a space is formed therein for accommodating a control board 9 (see FIG. 6) and the like. The front wall 3F, the rear wall 3S, the left wall 3L, and the right wall 3R each have a plate-like shape and are connected to a top wall 30 (see FIG. 6) of the base 3B. The front wall 3F, the rear wall 3S, the left wall 3L, and the right wall 3R extend upward from the front end, the rear end, the left end, and the right end, respectively, of the top wall 30 of the base 3B. The top wall 3U has a plate-like shape and is connected to the upper ends of the front wall 3F, the rear wall 3S, the left wall 3L, and the right wall 3R. The internal space surrounded by the front wall 3F, rear wall 3S, left wall 3L, right wall 3R, top wall 3U, and top wall 30 of the base 3B is called a cavity 10 (see FIG. 3).

[0013] As shown in FIGS. 1 and 2, the upper wall 3U includes an upper-left wall 31L and an upper-right wall 31R. The upper-left wall 31L is disposed between the upper end of the left wall 3L and the upper end of the front wall 3F and the rear wall 3S near their left ends. The upper-right wall 31R is disposed between the upper end of the right wall 3R and the upper end of the front wall 3F and the rear wall 3S near their right ends. As shown in FIG. 3, the right end of the upper-left wall 31L, the left end of the upper-right wall 31R, and the upper ends of the front wall 3F and the rear wall 3S form a rectangular opening 21. The opening 21 exposes the cavity 10. As shown in FIGS. 1 and 2, the lid 31 has a plate shape. When attached to the opening 21, the lid 31 closes the opening 21. On the other hand, when the lid 31 is detached from the opening 21, the opening 21 exposes the cavity 10, as shown in FIG. 3.

[0014] As shown in FIG. 4, partition walls 36L and 36R are provided on the upper wall 30 of the base 3B. The partition wall 36L is provided below the left end of the opening 21 (see FIG. 3). The partition wall 36R is provided below the right end of the opening 21 (see FIG. 3). The partition walls 36L and 36R are perpendicular to the left-right direction. A plurality of slit-shaped through-holes are formed in the partition walls 36L and 36R. The partition walls 36L and 36R divide the cavity 10 into three sections (cavities 10U, 10L, and 10R). The cavity 10L is a portion of the cavity 10 to the left of the partition wall 36L. The cavity 10R is a portion of the cavity 10 to the right of the partition wall 36R. The cavity 10U is a portion of the cavity 10 sandwiched between the partition walls 36L and 36R in the left-right direction and is located below the lid 31 when attached. The cavities 10U, 10L, and 10R accommodate a filter unit 6 and fans 5L and 5R, which will be described later, respectively.

[0015] As shown in Fig. 1, suction port 20U is formed in lid 31. Suction port 20F is formed in a portion of front wall 3F that overlaps with opening 21 in the left-right direction. As shown in Fig. 3, suction port 20S (see Fig. 3) is formed in a portion of rear wall 3S that overlaps with opening 21 in the left-right direction. Suction ports 20U, 20F, 20S each consist of a plurality of slit-shaped through-holes.

[0016] As shown in FIG. 6, openings 20L and 20R are formed at both left and right ends of the housing 2. The opening 20L is surrounded by the left ends of the top wall 3U, the front wall 3F, the rear wall 3S, and the top wall 30 of the base 3B. The opening 20L communicates with the cavity 10L (see FIG. 4). The opening 20R is surrounded by the right ends of the top wall 3U, the front wall 3F, the rear wall 3S, and the top wall 30 of the base 3B. The opening 20R communicates with the cavity 10R (see FIG. 4). The openings 20L and 20R face each other in the left-right direction.

[0017] The left wall 3L fits into the opening 20L, and the right wall 3R fits into the opening 20R. A circular air outlet 22L is provided in the left wall 3L. A circular air outlet 22R is provided in the right wall 3R. A louver 23 fits into each of the air outlets 22L, 22R. The louver 23 has multiple blades 23A arranged in parallel. The louver 23 changes the direction of air flowing through the gaps between each of the multiple blades 23A to a direction inclined with respect to the left-right direction. The louver 23 slides relative to the air outlets 22L, 22R, and can therefore rotate relative to the left wall 3L or the right wall 3R.

[0018] <Filter unit 6> The filter unit 6 purifies the air by removing dirt, dust, and the like. As shown in FIGS. 5 and 6, the filter unit 6 has a filter 60. The filter 60 is a HEPA filter. As shown in FIG. 5, the filter 60 has a shape in which mountain folds and valley folds are repeatedly formed on a thick filter substrate, i.e., a bellows-folded shape. The filter 60 has a first portion 6U, a second portion 6F, a third portion 6S, a second bend portion 60F, and a third bend portion 60S.

[0019] As shown in FIG. 6, the first section 6U, the second section 6F, and the third section 6S extend in the left-right direction. The first part 6U is perpendicular to the up-down direction. A second bent part 60F is connected to the front end of the first part 6U. The second bent part 60F extends forward from the connection part with the first part 6U while curving downward. A third bent part 60S is connected to the rear end of the first part 6U. The third bent part 60S extends backward from the connection part with the first part 6U while curving downward.

[0020] The second section 6F extends downward from the lower end of the second bent section 60F. That is, the second section 6F is connected to the first section 6U via the second bent section 60F and extends downward from near the front end of the first section 6U. The third section 6S extends downward from the lower end of the third bent section 60S. That is, the third section 6S is connected to the first section 6U via the third bent section 60S and extends downward from near the rear end of the first section 6U. The second section 6F and the third section 6S face each other in the front-to-rear direction below the first section 6U. As shown in FIG. 5, the cross section of the filter 60 when cut along a plane perpendicular to the left-to-right direction is substantially U-shaped.

[0021] The multiple accordion-folded folds formed in each of the first part 6U, the second part 6F, the third part 6S, the second bent part 60F, and the third bent part 60S all extend in the left-right direction and are perpendicular to the front-to-back and up-down directions.

[0022] The region below the first portion 6U, behind the second portion 6F, and in front of the third portion 6S, i.e., the region surrounded by the first portion 6U, the second portion 6F, the third portion 6S, the second bent portion 60F, and the third bent portion 60S, is referred to as the inner region 600. Of the first portion 6U, the second portion 6F, the third portion 6S, the second bent portion 60F, and the third bent portion 60S, the edge portion closest to the inner region 600 is referred to as the inner edge Ei, and the side opposite the inner edge Ei is referred to as the outer edge Eo. The inner edge Ei extends along an imaginary line connecting multiple folds that are closest to the inner region 600 among the multiple accordion-like folds of each of the first portion 6U, the second portion 6F, the third portion 6S, the second bent portion 60F, and the third bent portion 60S. The outer edge Eo extends along an imaginary line connecting a plurality of accordion-folded folds of each of the first part 6U, the second part 6F, the third part 6S, the second bend 60F, and the third bend 60S that are away from the internal region 600.

[0023] Note that the center of curvature of each of the second bent portion 60F and the third bent portion 60S is disposed in the inner region 600. Therefore, the inner edge Ei of each of the second bent portion 60F and the third bent portion 60S corresponds to an edge portion close to the center of curvature of each of the second bent portion 60F and the third bent portion 60S. The outer edge Eo of each of the second bent portion 60F and the third bent portion 60S corresponds to an edge portion separated from the center of curvature of each of the second bent portion 60F and the third bent portion 60S.

[0024] The intervals between the plurality of folds of the bellows folds of each of the first portion 6U, the second portion 6F, and the third portion 6S are the same. Hereinafter, this interval is denoted as d1. The interval d1 corresponds to the interval between the plurality of folds of the bellows folds of each of the first portion 6U, the second portion 6F, and the third portion 6S disposed along the inner edge Ei and the outer edge Eo. Among the plurality of folds of the bellows folds of each of the second bent portion 60F and the third bent portion 60S, the interval between the plurality of folds disposed along the outer edge Eo is denoted as d2. The interval d2 is larger than the interval d1 (d1 < d2). Among the plurality of folds of the bellows folds of each of the second bent portion 60F and the third bent portion 60S, the interval between the plurality of folds disposed along the inner edge Ei is denoted as d3. The interval d3 is the same as the interval d1 (d1 = d3), and the interval d2 is larger than the interval d3 (d2 > d3).

[0025] In a state where the filter unit 6 is housed in the cavity 10U of the housing 2, the second portion 6F of the filter 60 is disposed on the rear side with respect to the portion of the front wall 3F where the suction port 20F (see FIG. 1) is formed. The third portion 6S of the filter 60 is disposed on the front side with respect to the portion of the rear wall 3S where the suction port 20S (see FIG. 6) is formed. The first portion 6U of the filter 60 faces downward with respect to the opening 21 and is disposed below the lid 31 (see FIG. 1) attached to the opening 21.

[0026] As shown in FIG. 3, the filter unit 6 is exposed in a state where the lid 31 is detached from the opening 21. The user can take out the filter unit 6 from the cavity 10U through the opening 21.

[0027] <The first shape-retaining member <61>> As shown in FIG. 6, first shape-retaining members 61 are provided on both left and right ends of the filter 60. The first shape-retaining member 61 is a thin plate-like member made of nonwoven fabric. The first shape-retaining member 61 has a shape-retaining portion 61A and a gripping portion 61B. The shape-retaining portion 61A has the same shape as the cross-sectional shape of the filter 60.

[0028] The shape-retaining portion 61A is bonded to both left-right ends of the filter 60 and retains the shape of the filter 60 so that the cross-sectional shape of the filter 60 remains U-shaped. The grip portion 61B is provided at portions of the shape-retaining portion 61A located at both left-right ends of the first portion 6U of the filter 60, i.e., at the upper end of the shape-retaining portion 61A, and extends upward. The grip portion 61B protrudes above the upper end of the first portion 6U of the filter 60. The user grasps the grip portion 61B when removing the filter 60 from the cavity 10U. On the other hand, when the lid 31 is attached to the opening 21, the grip portion 61B is folded in the left-right direction away from the filter 60 and stored in the cavity 10U. At this time, the grip portion 61B is located at the same position as the upper end of the first portion 6U of the filter 60 in the vertical direction or below the upper end of the first portion 6U of the filter 60, and does not protrude upward. The grip portion 61B may be bent so as to abut on the inside in the left-right direction, more specifically, on the upper end of the first portion 6U of the filter 60.

[0029] Sealing members 62 are provided at both left and right ends of the filter 60. More specifically, the sealing members 62 are provided on the side of the first shape-retaining members 61 provided at both left and right ends of the filter 60 opposite the side on which the filter 60 is provided. The sealing members 62 are located between the shape-retaining portion 61A provided at the left end of the filter 60 and the partition wall 36L (see FIG. 4), and between the shape-retaining portion 61A of the first shape-retaining member 61 provided at the right end of the filter 60 and the partition wall 36R. The sealing members 62 have the same shape as the cross-sectional shape of the filter 60.

[0030] The sealing member 62 is made of an elastic material. For example, soft urethane foam is used as the material for the sealing member 62. More specifically, it is closed-cell soft urethane foam. The sealing member 62 fills the gap between the filter 60 (first shape-retaining member 61) and the partition wall 36L in the left-right direction, and the gap between the filter 60 (first shape-retaining member 61) and the partition wall 36R. The provision of the sealing member 62 improves the efficiency with which the fans 5L and 5R suction air through the filter 60.

[0031] <Second shape-retaining member 7> The second shape-retaining member 7 will be described with reference to Figures 7 to 9. Note that the second shape-retaining member 7 is omitted in Figures 1 to 6. In this embodiment, it is possible to selectively use any one of second shape-retaining members 7A to 7D (see Figure 7), 7E to 7H (see Figure 8), 7I, and 7J (see Figure 9) as the second shape-retaining member 7, or to use a combination of at least two of the second shape-retaining members 7A to 7J.

[0032] The second shape-retaining member 7 connects multiple mountain folds of adjacent accordion folds of the filter 60 or multiple valley folds of adjacent accordion folds. As a result, the second shape-retaining member 7 maintains the multiple accordion folds and prevents the multiple folds from opening due to a rise in temperature. A hot melt adhesive or adhesive tape is used as the material for the second shape-retaining member 7. When a hot melt adhesive is used, the hot melt adhesive is liquefied by heating and applied to the filter 60, and then the hot melt adhesive is cooled to form the second shape-retaining member 7. When an adhesive tape is used, the second shape-retaining member 7 is formed by adhering a single-sided adhesive tape, which has a base material with an adhesive applied to one side, to the filter 60.

[0033] Hereinafter, as shown in FIG. 7B , the lower end of the second portion 6F of the filter 60 is referred to as the second tip portion 65F, and the lower end of the third portion 6S of the filter 60 is referred to as the third tip portion 65S. A bellows-folded fold adjacent to the second tip portion 65F in the direction along the filter 60 with respect to the second tip portion 65F is referred to as the second adjacent fold 65M. A downward-facing surface of the portion of the filter 60 between the second tip portion 65F and the second adjacent fold 65M is referred to as the second end surface 66F. A bellows-folded fold adjacent to the third tip portion 65S in the direction along the filter 60 with respect to the third tip portion 65S is referred to as the third adjacent fold 65N. A downward-facing surface of the portion of the filter 60 between the third tip portion 65S and the third adjacent fold 65N is referred to as the third end surface 66S.

[0034] In this embodiment, filters 60A (see FIGS. 7(B)(D) and 8(B)(D)) and 60B (see FIGS. 7(C)(E) and 8(C)(E)) are used as the filter 60. The second tip 65F and the third tip 65S are located at different positions. As shown in FIGS. 7(B)(D) and 8(B)(D), in the filter 60A, the second tip 65F and the third tip 65S are located at the inner edge Ei of the filter 60. On the other hand, as shown in FIGS. 7(C)(E) and 8(C)(E), in the filter 60B, the second tip 65F and the third tip 65S are located at the outer edge Eo of the filter 60B.

[0035] 7(A) and 8(A), the second shape-retaining members 7A to 7H are provided in the left-right center of the filter 60. The left-right length of the second shape-retaining members 7A to 7H is shorter than the left-right length of the filter 60. The second shape-retaining members 7A to 7H extend across the first section 6U, the second section 6F, and the third section 6S of the filter 60 in a direction perpendicular to the direction of the multiple accordion-like folds.

[0036] 7(B), the second shape-retaining member 7A has a shape-retaining portion 71A. The shape-retaining portion 71A extends in a strip shape from a second tip portion 65F located on the inner edge Ei of the filter 60A, through the inner edges Ei of the second portion 6F, the second bent portion 60F, the first portion 6U, the third bent portion 60S, and the third portion 6S, to the third tip portion 65S located on the inner edge Ei.

[0037] 7(C), the second shape-retaining member 7B has a shape-retaining portion 71B. The shape-retaining portion 71B extends in a strip-like shape from the second tip portion 65F located at the outer edge Eo of the filter 60B, through the outer edges Eo of the second portion 6F, the second bent portion 60F, the first portion 6U, the third bent portion 60S, and the third portion 6S, and to the third tip portion 65S located at the outer edge Eo. In other words, the second shape-retaining member 7A is provided on the inner edge Ei of the filter 60A, and the second shape-retaining member 7B is provided on the outer edge Eo of the filter 60B.

[0038] As shown in Fig. 7(D), the second shape-retaining member 7C has shape-retaining portions 71A and 72A. The shape-retaining portion 71A is the same as the shape-retaining portion 71A of the second shape-retaining member 7A (see Fig. 7(B)). The shape-retaining portion 72A extends in a strip-like shape from the second adjacent fold 65M located at the outer edge Eo of the filter 60A, through the outer edges Eo of the second portion 6F, the second bent portion 60F, the first portion 6U, the third bent portion 60S, and the third portion 6S, and to the third adjacent fold 65N located at the outer edge Eo of the filter 60A.

[0039] As shown in FIG. 7(E), the second shape-retaining member 7D has shape-retaining portions 71B and 72B. The shape-retaining portion 71B is identical to the shape-retaining portion 71B of the second shape-retaining member 7B (see FIG. 7(C)). The shape-retaining portion 72B extends in a strip-like shape from the second adjacent fold 65M located on the inner edge Ei of the filter 60B, through the inner edges Ei of the second portion 6F, the second bent portion 60F, the first portion 6U, the third bent portion 60S, and the third portion 6S, and to the third adjacent fold 65N located on the inner edge Ei of the filter 60B. In other words, the second shape-retaining members 7C and 7D are both provided on the inner edge Ei and outer edge Eo of the filter 60B.

[0040] As shown in FIG. 8(B), the second shape-retaining member 7E differs from the second shape-retaining member 7A (see FIG. 7(B)) in that it has shape-retaining portions 73A and 74A in addition to the shape-retaining portion 71A of the second shape-retaining member 7A. The shape-retaining portion 73A is provided on a portion of the second end surface 66F of the filter 60A. The shape-retaining portion 73A is connected to the shape-retaining portion 71A at the second tip portion 65F. The shape-retaining portion 74A is provided on a portion of the third end surface 66S of the filter 60A. The shape-retaining portion 74A is connected to the shape-retaining portion 71A at the third tip portion 65S. The left-right length of the shape-retaining portions 73A and 74A is the same as the left-right length of the shape-retaining portion 71A.

[0041] As shown in FIG. 8(C), the second shape-retaining member 7F differs from the second shape-retaining member 7B (see FIG. 7(C)) in that it has shape-retaining portions 73B and 74B in addition to the shape-retaining portion 71B of the second shape-retaining member 7B. The shape-retaining portion 73B is provided on a portion of the second end surface 66F of the filter 60B. The shape-retaining portion 73B is connected to the shape-retaining portion 71B at the second tip portion 65F. The shape-retaining portion 74B is provided on a portion of the third end surface 66S of the filter 60B. The shape-retaining portion 74B is connected to the shape-retaining portion 71B at the third tip portion 65S. The left-right length of the shape-retaining portions 73B and 74B is the same as the left-right length of the shape-retaining portion 71B.

[0042] As shown in Figure 8(D), the second shape-retaining member 7G has shape-retaining portions 71A, 72A, 73A, and 74A. The shape-retaining portions 71A and 72A are the same as the shape-retaining portions 71A and 72A of the second shape-retaining member 7C (see Figure 7(D)). The shape-retaining portions 73A and 74A are the same as the shape-retaining portions 73A and 74A of the second shape-retaining member 7E (see Figure 8(B)). The shape-retaining portion 73A is connected to the shape-retaining portion 72A at the second adjacent fold line 65M. The shape-retaining portion 74A is connected to the shape-retaining portion 72A at the third adjacent fold line 65N.

[0043] As shown in FIG. 8(E), the second shape-retaining member 7H has shape-retaining portions 71B, 72B, 73B, and 74B. The shape-retaining portions 71B and 72B are the same as the shape-retaining portions 71B and 72B of the second shape-retaining member 7D (see FIG. 7(E)). The shape-retaining portions 73B and 74B are the same as the shape-retaining portions 73B and 74B of the second shape-retaining member 7F (see FIG. 8(C)). The shape-retaining portion 73B is connected to the shape-retaining portion 72B at the second adjacent fold line 65M. The shape-retaining portion 74B is connected to the shape-retaining portion 72B at the third adjacent fold line 65N. In other words, the second shape-retaining members 7G and 7H are both provided across the inner edge Ei, outer edge Eo, second end face 66F, and third end face 66S of the filter 60.

[0044] 8(B) to 8(E) may extend from the second tip 65F of the second end surface 66F to the second adjacent fold 65M, or may extend from the second tip 65F of the second end surface 66F to a portion of the second end surface 66F closer to the second tip 65F than the second adjacent fold 65M. That is, the end of each of the shape retaining portions 73A and 73B that is close to the second adjacent fold 65M may be spaced closer to the second tip 65F than the second adjacent fold 65M. The shape retaining portions 74A and 74B may extend from the third tip 65S of the third end surface 66S to the third adjacent fold 65N, or may extend from the third tip 65S of the third end surface 66S to a portion of the third end surface 66S closer to the third tip 65S than the third adjacent fold 65N. That is, the ends of the shape-retaining portions 74A and 74B that are close to the third adjacent fold 65N may be spaced apart from the third adjacent fold 65N toward the third tip portion 65S.

[0045] 8(D) and 8(E) may extend from the second adjacent fold 65M of the second end surface 66F to a portion closer to the second adjacent fold 65M than the second tip 65F. That is, the ends of the shape retaining portions 73A and 73B closest to the second tip 65F may be spaced closer to the second adjacent fold 65M than the second tip 65F. The shape retaining portions 74A and 74B may extend from the third adjacent fold 65N of the third end surface 66S to a portion closer to the third adjacent fold 65N than the third tip 65S. That is, the ends of the shape retaining portions 74A and 74B closest to the third tip 65S may be spaced closer to the third adjacent fold 65N than the third tip 65S.

[0046] The second shape-retaining member 7I shown in Figure 9(A) and the second shape-retaining member 7J shown in Figure 9(B) differ from the second shape-retaining members 7E to 7H shown in Figure 8 in the shapes of the shape-retaining portions 73A, 73B provided on the second end surface 66F and the shape-retaining portions 74A, 74B provided on the second end surface 66F.

[0047] 9(A), shape retaining portions 73A and 73B are provided over the entire second end surface 66F, and shape retaining portions 74A and 74B are provided over the entire third end surface 66S. The left-right length of the shape retaining portions 73A, 73B, 74A, and 74B is the same as the left-right length of the filter 60, and is longer than the front-rear length of the portions of the shape retaining portions 71A, 71B, 72A, and 72B that are provided at the second tip portion 65F and the third tip portion 65S. In other words, the shape retaining portions 73A, 73B, 74A, and 74B of the second shape retaining member 7I are longer in the left-right direction than the shape retaining portions 73A, 73B, 74A, and 74B of the second shape retaining members 7E to 7H.

[0048] The shape retaining portions 73A, 73B, 74A, and 74B of the second shape retaining member 7J shown in Fig. 9(B) have a shape obtained by dividing the shape retaining portions 73A, 73B, 74A, and 74B of the second shape retaining member 7I shown in Fig. 9(A) into three in the left-right direction. The left-right length of each of the divided shape retaining portions 73A, 73B, 74A, and 74B is longer than the front-rear length of the portions of the shape retaining portions 71A, 71B, 72A, and 72B that are provided at the second tip portion 65F and the third tip portion 65S.

[0049] <Method of manufacturing filter unit 6> First, heat is applied to a planar filter substrate to heat it. Next, the filter substrate is folded along the accordion-like folds while in a hot state. After that, the filter substrate is cooled. As a result, the accordion-like folds formed in the filter substrate are maintained.

[0050] Next, the filter substrate with multiple accordion-like folds formed thereon is folded in two places to create a filter 60 having a first section 6U, a second section 6F, and a third section 6S. Next, a first shape-retaining member 61, a sealing member 62, and a second shape-retaining member 7 are attached to the filter 60. With the above steps, the filter unit 6 is completed.

[0051] The filter 60 manufactured as described above will deform when the temperature rises, and the multiple accordion-like folds will try to return to their original shape. However, since the first shape-retaining member 61 and the second shape-retaining member 7 are attached, the multiple accordion-like folds of the filter 60 are maintained even when the temperature rises.

[0052] <Blower 5> As shown in FIG. 4, the fan 5 is an axial-flow fan. The fans 5L and 5R are provided at both left-right ends of the housing 2. More specifically, the fan 5L is fixed to the cavity 10L via a sealing member 55L (see FIG. 6). The fan 5L is adjacent to the right side of the left wall 3L. The sealing member 55L is made of an elastic member (e.g., soft urethane foam) and fills gaps between the upper left wall 31L, the front wall 3F, the rear wall 3S, and the upper wall 30 of the base 3B and a casing 51 of the fan 5L (described later). The fan 5R is fixed to the cavity 10R via a sealing member 55R (see FIG. 6). The fan 5R is adjacent to the left side of the right wall 3R. The sealing member 55R is made of an elastic member (e.g., soft urethane foam) and fills the gaps between the upper right wall 31R, the front wall 3F, the rear wall 3S, and the upper wall 30 of the base 3B and the casing 51 of the fan 5R, which will be described later. The provision of the sealing members 55L, 55R improves the efficiency with which the fans 5L, 5R suction air through the filter 60. The filter unit 6 housed in the hollow portion 10U is disposed between the fans 5L, 5R in the left-right direction.

[0053] As shown in Figures 4 and 6, each of the fans 5L and 5R includes a casing 51, a fan 52, and a motor 53. The casing 51 has a rectangular cylindrical shape. A through hole in the casing 51 extends in the left-right direction. The motor 53 is fixed to the casing 51 near the center of the through hole. The rotation shaft of the motor 53 extends in the left-right direction. The fan 52 is disposed inside the through hole in the casing 51 and is rotated by the motor 53.

[0054] The fan 52 generates an air current by rotation. The air current generated by the fan 52 of the blower 5L passes through a through-hole in the casing 51 of the blower 5L from right to left. The air current generated by the fan 52 of the blower 5R passes through a through-hole in the casing 51 of the blower 5L from left to right.

[0055] <Control board 9> As shown in FIG. 6, the bottom wall 32 of the base 3B is removable. The control board 9 (main board 9A and LED board 9B) and switch 9C are housed in the internal space of the base 3B. A control circuit, a USB connector 90A, a cable connector 90B, etc. are mounted on the main board 9A. A USB cable for supplying power to the air purifier 1A is connected to the USB connector 90A. The USB connector 90A is exposed from a recess 33 provided on the left side surface of the base 3B. A cable 59 extending from the fans 5L and 5R is connected to the cable connector 90B. An LED is mounted on the LED board 9B. The LED is exposed through a through-hole 34 provided on the front side surface of the base 3B. The switch 9C is a slide switch. A knob 35A of the switch 9C protrudes forward through a through-hole 35 provided on the front side surface of the base 3B.

[0056] <Operation overview> By connecting a USB cable to the USB connector 90A, the air purifier 1A is powered. In this state, the user operates the knob 35A to start air purification using the air purifier 1A. The control circuit on the main board 9A drives the blowers 5L and 5R, more specifically, the motors 53 of the blowers 5L and 5R, rotating their respective fans 52. The blowers 5L and 5R generate airflow. This airflow allows the air purifier 1A to draw air from the outside into the cavity 10U through the upper inlet 20U, front inlet 20F, and rear inlet 20S of the housing 2. The drawn air passes through filters 60 arranged inside the inlets 20U, 20F, and 20S and is purified. The blowers 5L and 5R then direct the purified air within the cavity 10U to the left or right. As a result, the purified air is blown outward in the left and right directions through the left air outlet 22L and the right air outlet 22R of the housing 2.

[0057] <Actions and Effects of This Embodiment> When the air purifier 1A is used with the filter unit 6 attached, it can purify the air with the filter 60. Furthermore, when the filter unit 6 becomes dirty during use, the air purifier 1A can maintain its air purification function by replacing the filter unit 6 with another filter unit 6.

[0058] The filter unit 6 includes a second shape-retaining member 7 that maintains the shape of the filter 60. The second shape-retaining member 7 is provided at least on a portion of the second end 65F and the third end 65S of the filter 60. The second end 65F and the third end 65S correspond to ends of the filter 60 that are perpendicular to the direction of the accordion-folded folds. If the temperature inside the cavity 10U rises while the filter unit 6 is attached to the air purifier 1A, the second end 65F and the third end 65S may deform due to the temperature change in the filter 60. However, the provision of the second shape-retaining member 7 restricts the deformation of the second end 65F and the third end 65S, thereby reducing the possibility of the second end 65F and the third end 65S of the filter 60 being rolled up during use. Therefore, the filter unit 6 reduces deformation of the filter 60 and suppresses a decrease in the air purification function of the air purifier 1A.

[0059] The second shape-retaining member 7 extends from the second tip 65F through the second section 6F, the first section 6U, and the third section 6S to the third tip 65S. Therefore, the portions of the second shape-retaining member 7 located at the second tip 65F and the third tip 65S of the filter 60 restrict deformation across the first section 6U, the second section 6F, and the third section 6S of the filter unit 6, reducing the possibility of these sections rolling up during use. Furthermore, the portions of the second shape-retaining member 7 extending across the first section 6U, the second section 6F, and the third section 6S of the filter 60 allow the filter unit 6 to maintain the spacing of the folds throughout the first section 6U, the second section 6F, and the third section 6S. Furthermore, maintaining the spacing of the folds helps maintain the air purifying function of the filter 60 compared to when the filter 60 deforms and the spacing of the folds narrows.

[0060] The second shape-retaining member 7A (see FIG. 7(B)) has a shape-retaining portion 71A (see FIG. 7(B)) that extends through the inner edge Ei of the filter 60A. Therefore, the second shape-retaining member 7A can maintain the spacing between the folds of the first part 6U, the second part 6F, and the third part 6S of the filter 60A at the inner edge Ei of the filter 60A. When the filter substrate on which multiple accordion-like folds have been formed is folded into a U-shape, it is easier to provide the second shape-retaining member 7A at the inner edge Ei of the filter 60A than at the outer edge Eo of the filter 60A.

[0061] The second shape-retaining member 7B (see FIG. 7(C)) has a shape-retaining portion 71B (see FIG. 7(C)) that extends through the outer edge Eo of the filter 60B. Therefore, the second shape-retaining member 7B can maintain the spacing between the folds of the first portion 6U, the second portion 6F, and the third portion 6S of the filter 60B at the outer edge Eo of the filter 60B. Because the filter substrate, on which multiple accordion-like folds have been formed, is heated and molded into a U-shape, when the U-shaped filter 60B is heated (heated), a force is generated in the filter 60B that causes it to return from the U-shape to a flat plate shape so as to release stress. In such a case, providing the second shape-retaining member 7B at the outer edge Eo makes it easier to restrict deformation due to this returning force.

[0062] The shape retaining portions 71A and 72A of the second shape retaining member 7C (see FIG. 7(D)) and the shape retaining portions 71B and 72B of the second shape retaining member 7D (see FIG. 7(E)) extend through the inner edge Ei and outer edge Eo of the filter 60. Therefore, the second shape retaining members 7C and 7D can maintain the spacing between the folds of the first part 6U, the second part 6F, and the third part 6S of the filter 60B on both sides of the inner edge Ei and the outer edge Eo of the filter 60.

[0063] The second shape-retaining members 7E and 7G have a shape-retaining portion 73A provided on the second end face 66F and a shape-retaining portion 74A provided on the third end face 66S (see FIGS. 8(B) and 8(D)). The second shape-retaining members 7F and 7H have a shape-retaining portion 73B provided on the second end face 66F and a shape-retaining portion 74B provided on the third end face 66S (see FIGS. 8(C) and 8(E)). The second shape-retaining members 7E to 7H can increase the force that retains the shape of the second end face 66F and the third end face 66S by using the shape-retaining portions 73A, 74A, 73B, and 74B. Therefore, the filter unit 6 can more reliably prevent the filter 60 from curling up at the second tip portion 65F and the third tip portion 65S.

[0064] The shape retaining portions 73A, 74A, 73B, and 74B provided on the second end face 66F and the third end face 66S of the second shape retaining members 7I and 7J are longer in the left-right direction than the shape retaining portions 71A, 71B, 72A, and 72B (see FIGS. 9(A) and 9(B)). In other words, the left-right length of the portions of the second shape retaining members 7I and 7J provided on the second end face 66F and the third end face 66S is longer than the left-right length of the portions of the second shape retaining members 7I and 7J located at the second tip end portion 65F and the third tip end portion 65S. Therefore, the filter unit 6 can suppress curling up over a wider range in the left-right direction at the second end face 66F and the third end face 66S of the filter 60.

[0065] In the filter unit 6, the second shape-retaining member 7 can be formed of a hot melt adhesive or adhesive tape, so that the shape of the filter 60 can be easily maintained by the second shape-retaining member 7.

[0066] The first shape-retaining member 61 has a grip portion 61B that can be gripped by the user, so that the user can easily attach or detach the filter unit 6 to or from the air purifier 1A by gripping the grip portion 61B.

[0067] The grip portion 61B is bendable and can be deformed between a state in which it protrudes above the first portion 6U of the filter 60 and a state in which it does not protrude above the first portion 6U of the filter 60. This prevents the grip portion 61B from getting in the way when the filter unit 6 is attached to the air purifier 1A and used.

[0068] A sealing member 62 is provided on the first shape-retaining member 61 on the side opposite in the left-right direction to the side on which the filter 60 is provided. When the filter unit 6 is attached to the air purifier 1A for use, the sealing member 62 fills and seals the gap between the filter 60 and the partition walls 36L, 36R. This improves the efficiency with which the fans 5L, 5R suction air through the filter 60.

[0069] The filter 60 has a second bent portion 60F connecting the first portion 6U and the second portion 6F, and a third bent portion 60S connecting the first portion 6U and the third portion 6S. The filter 60 can efficiently purify not only the air passing through the first portion 6U, the second portion 6F, and the third portion 6S, but also the air passing through the second bent portion 60F and the third bent portion 60S. Therefore, the filter unit 6 can more efficiently purify the air by the filter 60 than when the first portion 6U and the second portion 6F, and the first portion 6U and the third portion 6S are directly connected.

[0070] The spacing d1 between the multiple accordion-folded folds in the first section 6U, the second section 6F, and the third section 6S is the same as the spacing d3 between the multiple accordion-folded folds located on the inner edge Ei of each of the second bent section 60F and the third bent section 60S (d1 = d3). In this case, the filter unit 6 can make the air purification effect at the second bent section 60F and the third bent section 60S of the filter 60 equivalent to that of the first section 6U, the second section 6F, and the third section 6S.

[0071] The distance d2 between the plurality of folds of the bellows folds located at the outer edges Eo of the second bent portion 60F and the third bent portion 60S is larger than the distance d1 between the plurality of folds of the bellows folds in the first portion 6U, the second portion 6F, and the third portion 6S (d1 < d2). Also, the distance d2 between the plurality of folds of the bellows folds located at the outer edges Eo of the second bent portion 60F and the third bent portion 60S is larger than the distance d3 between the plurality of folds of the bellows folds located at the inner edges Ei of the second bent portion 60F and the third bent portion 60S (d2 > d3). In these cases, the filter unit 6 can improve the air permeability in the second bent portion 60F and the third bent portion 60S of the filter 60, so that the air cleaning effect can be maintained well in the second bent portion 60F and the third bent portion 60S.

[0072] <Modified Example> The present invention can be variously modified. The blower 5 of the air cleaner 1A may be provided on at least one of the front wall 3F, the rear wall 3S, and the upper wall 3U of the housing 2. In this case, at least one of the first portion 6U, the second portion 6F, and the third portion 6S of the filter 60 and the blower 5 are arranged to face each other, and the filter unit 6 is not arranged between the blowers 5L and 5R. The filter unit 6 may be fixed to the air cleaner 1A and may be non-detachable.

[0073] The extending directions of the second portion 6F and the third portion 6S of the filter 60 may be inclined with respect to the vertical direction. For example, the second portion 6F may extend obliquely downward in front from the lower end portion of the second bent portion 60F, and the third portion 6S may extend obliquely downward in the rear from the lower end portion of the third bent portion 60S. The distance in the front-rear direction between the second portion 6F and the third portion 6S may gradually increase downward. Also, for example, the second portion 6F may extend obliquely downward in the rear from the lower end portion of the second bent portion 60F, and the third portion 6S may extend obliquely downward in front from the lower end portion of the third bent portion 60S. The distance in the front-rear direction between the second portion 6F and the third portion 6S may gradually decrease downward.

[0074] The second shape-retaining member 7K shown in FIGS. 10(A) and 10(B) differs from the second shape-retaining member 7E in that it has shape-retaining portions 76A and 76B instead of the shape-retaining portion 71A shown in FIG. 8(B). The shape-retaining portion 76A is provided only in the vicinity of the second tip portion 65F of the inner edge Ei. The shape-retaining portion 76B is provided only in the vicinity of the third tip portion 65S of the inner edge Ei. The second shape-retaining member 7L shown in FIGS. 10(A) and 10(C) differs from the second shape-retaining member 7F in that it has shape-retaining portions 77A and 77B instead of the shape-retaining portion 71B shown in FIG. 8(C). The shape-retaining portion 77A is provided only in the vicinity of the second tip portion 65F of the outer edge Eo. The shape-retaining portion 77B is provided only in the vicinity of the third tip portion 65S of the outer edge Eo.

[0075] 10, the second shape-retaining members 7 may be provided only in the vicinity of the second tip portion 65F and the third tip portion 65S of the inner edge Ei and the outer edge Eo, and may not be provided over the entire area of ​​the inner edge Ei and the outer edge Eo. For example, the second shape-retaining members 7 may be provided only on at least one of the inner edge Ei and the outer edge Eo of the second portion 6F and the third portion 6S of the filter 60, and may not be provided on the inner edge Ei or the outer edge Eo of the first portion 6U.

[0076] The second shape-retaining member 7M shown in Fig. 11(A) has shape-retaining portions 78A and 78B. The shape-retaining portion 78A is provided between the second tip portion 65F of the filter 60A and a bellows-folded fold (hereinafter referred to as the "second nearest fold 65P") adjacent to and above the second tip portion 65F, connecting them together. The shape-retaining portion 78B is provided between the third tip portion 65S of the filter 60A and a bellows-folded fold (hereinafter referred to as the "third nearest fold 65Q") adjacent to and above the third tip portion 65S, connecting them together. The shape-retaining portions 78A and 78B are arranged along the inner edge Ei of the filter 60A.

[0077] The second shape-retaining member 7N shown in FIG. 11(B) has shape-retaining portions 79A and 79B. Shape-retaining portion 79A is provided between and connects the second tip portion 65F and the second adjacent fold 65P of filter 60B. Shape-retaining portion 78B is provided between and connects the third tip portion 65S and the third adjacent fold 65Q of filter 60B. Shape-retaining portions 79A and 79B are arranged along the outer edge Eo of filter 60B. In both of FIGS. 11(A) and 11(B), the distance between the second tip portion 65F and the second adjacent fold 65P and the distance between the third tip portion 65S and the third adjacent fold 65Q are smaller than distance d1 (see FIG. 5).

[0078] 11(A) and 11(B), the positions of the second tip portion 65F and the second adjacent fold 65P may coincide. That is, the shape retaining portions 78A and 78B of the second shape retaining member 7M may bond the second tip portion 65F and the second adjacent fold 65P. Similarly, the shape retaining portions 79A and 79B of the second shape retaining member 7N may bond the second tip portion 65F and the second adjacent fold 65P.

[0079] The material of the second shape-retaining member 7 is not limited to hot melt adhesive and adhesive tape, and other materials may be used. The second shape-retaining member 7 is not limited to connecting multiple mountain folds or multiple valley folds of adjacent accordion folds in the filter 60. For example, the second shape-retaining member 7 may be formed by bonding opposing ridge lines, among the portions (ridge lines) that extend across the folds in the accordion-folded filter 60, with an adhesive.

[0080] The gripping portion 61B may be provided on a member separate from the first shape-retaining member 61. For example, the gripping portion 61B may be provided directly on the filter 60, or on the sealing member 62. The gripping portion 61B may be slidable in the up and down direction relative to the filter 60. The first shape-retaining member 61 may be elastically deformable, and may have the function of filling and sealing the gap between the filter 60 and the partition walls 36L, 36R. In this case, the sealing member 62 may not be provided.

[0081] The filter 60 may not have the second bent portion 60F and the third bent portion 60S. In this case, the second portion 6F may be directly connected to the front end of the first portion 6U, and the third portion 6S may be directly connected to the rear end of the first portion 6U. In this case, the angle between the first portion 6U and the second portion 6F and the angle between the first portion 6U and the third portion 6S may be a right angle. The first portion 6U may be curved convexly upward.

[0082] The spacing d1 between the accordion-folded folds in the first section 6U, the second section 6F, and the third section 6S may be the same as the spacing d2 between the accordion-folded folds located at the outer edge Eo of each of the second bent section 60F and the third bent section 60S (d1 = d2). The spacing d3 between the accordion-folded folds located at the inner edge Ei of each of the second bent section 60F and the third bent section 60S may be smaller than the spacing d1 between the accordion-folded folds in the first section 6U, the second section 6F, and the third section 6S (d1 > d2). The second bent section 60F and the third bent section 60S do not have to have an accordion-folded shape. For example, the second bent section 60F and the third bent section 60S may be curved and planar.

[0083] The second shape-retaining members 7 may be provided at a plurality of different positions in the left-right direction of the filter 60. Specifically, for example, the second shape-retaining members 7E to 7H shown in Fig. 8 may be provided at the positions of three quadrants that divide the filter 60 into four equal parts in the left-right direction.

[0084] An air purifier 1B according to a modified example will be described with reference to Figure 12. Air purifier 1B differs from air purifier 1A in that a grip 41 is provided at the left end 40 of lid 31. The cross-sectional shape of grip 41 taken along a plane perpendicular to the front-to-rear direction (the shape shown in enlarged area W) has a U-shape that opens upward and extends from one end 411 to the other end 412. One end 411 connects to the center in the front-to-rear direction at left end 40 of lid 31. The other end 412 extends higher than one end 411 and higher than the upper-left wall 31L.

[0085] A locking piece 413 is provided on the grip portion 41 at a position below the other end 412. The locking piece 413 protrudes to the left from a position below the other end 412 of the grip portion 41. The grip portion 41 can elastically deform in the left-right direction so that the other end 412 approaches or moves away from the one end 411. The grip portion 41 is a snap fit, and the locking piece 413 engages with the underside of the upper left wall 31L, thereby maintaining the lid 31 attached to the housing 2. On the other hand, when the user presses the other end 412 of the grip portion 41 to the right so that it approaches the one end 411, the engagement between the locking piece 413 and the upper left wall 31L is released. In this state, the user can remove the lid 31 from the housing 2 by lifting the grip portion 41 upward.

[0086] Air purifier 1B in this modified example also differs from air purifier 1A in that louver 8 is provided instead of louver 23. As shown in FIG. 12, louver 8 fits into air outlets 22L, 22R (see FIG. 4). Louver 8 includes a frame 81, a plurality of frames 82, a plurality of blades 83, and a plurality of closure plates 84. Frame 81 has the same shape as air outlets 22L, 22R when viewed from the left side, and is rectangular in this modified example.

[0087] The multiple frames 82 extend vertically within the frame 81 and are lined up horizontally. The multiple blades 83 extend horizontally within the frame 81 and are lined up vertically. The blades 83 extend from the inside to the outside in the horizontal direction as they go from top to bottom. Multiple openings 85 are formed in the louver 8 by the multiple frames 82 and the multiple blades 83 within the frame 81. Blocking plates 84 are provided at the openings 85 at the four corners and the central opening 85 out of the multiple openings 85. This prevents the user from viewing the inside of the housing 2 from either the left or right side of the housing 2. The louver 8 uses the multiple blades 83 to guide the air flowing from the inside to the outside of the housing 2 in a direction that is inclined downward with respect to the horizontal direction.

[0088] <Other> The front-to-rear direction is an example of the "first direction" of the present invention. The front side is an example of the "one side of the first direction" of the present invention. The rear side is an example of the "other side of the first direction" of the present invention. The up-down direction is an example of the "second direction," "third direction," or "orthogonal direction" of the present invention. The bottom side is an example of the "one side of the second direction," "one side of the third direction," or "one side of the orthogonal direction" of the present invention. The top side is an example of the "other side of the second direction," "other side of the third direction," or "other side of the orthogonal direction" of the present invention. The left-to-right direction is an example of the "fold direction" of the present invention. The sealing member 62 is an example of the "elastic member" of the present invention. [Explanation of symbols]

[0089] 1A: Air purifier 2: Housing 5, 5L, 5R: Blower 6: Filter unit 6F: Part 2 6S: Part 3 6U: Part 1 7, 7A, 7B, 7C, 7D, 7E, 7F, 7G, 7H, 7I, 7J, 7K, 7L, 7M, 7N: 2nd shape retaining member 10: Cavity 31: Lid 60, 60A, 60B: Filter 60F: 2nd bending part 60S: 3rd bending part 61: First shape retaining member 62: Sealing material 65F: 2nd tip 65M: Second adjacent fold 65P: Second adjacent fold 66F: 2nd end face 65S: 3rd tip 65N: Third adjacent fold 65Q: Third adjacent fold 66S: 3rd end surface

Claims

1. A filter having an accordion-like shape, a first portion; a second portion extending from an end of the first portion on one side in a first direction to one side in a second direction intersecting with the first direction; and a third portion extending from an end of the first portion on the other side in the first direction to one side in a third direction intersecting with the first direction, the first portion and the second portion are connected via a second bent portion, the first portion and the third portion are connected via a third bent portion, the second bent portion and the third bent portion have inner edges close to a center of curvature and outer edges spaced apart from the center of curvature, A fold direction, which is a direction in which the accordion-folded folds of each of the first part, the second part, and the third part extend, is perpendicular to the first direction, the second direction, and the third direction; an interval between the plurality of accordion-folded folds in the first portion, an interval between the plurality of accordion-folded folds in the second portion, an interval between the plurality of accordion-folded folds in the third portion, and an interval between the plurality of accordion-folded folds located on the inner edge of each of the second bent portion and the third bent portion are the same; an interval between the plurality of accordion-folded folds located at the outer edge of each of the second bent portion and the third bent portion is larger than an interval between the plurality of accordion-folded folds in the first portion, an interval between the plurality of accordion-folded folds in the second portion, and an interval between the plurality of accordion-folded folds in the third portion; the filter; a first shape-retaining member that is bonded to both ends of the filter in the fold direction and that retains the shape of the filter so as to maintain the plurality of accordion-folded folds; a second shape-retaining member provided at a second tip portion which is an end portion on one side in the second direction of the second portion and a third tip portion which is an end portion on one side in the third direction of the third portion, and extending in the fold direction; A filter unit comprising:

2. 2. The filter unit according to claim 1, wherein the length of the second shape-retaining member in the folding direction is the same as the length of the filter.

3. 2. The filter unit according to claim 1, wherein the first shape-retaining member is a thin plate-like member made of nonwoven fabric.

4. 2. The filter unit according to claim 1, wherein the first shape-retaining member has the same cross-sectional shape as the filter.

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