KR101053443B1 - Filter frame and manufacturing method thereof - Google Patents

Abstract

According to the present invention, the inner frame and the outer frame accommodating the medium filter and the prefilter, respectively, can be quickly pressed by pressing without welding, thereby greatly improving productivity, and increasing durability and airtightness. It is about. Method for producing a filter frame according to the present invention as a means for achieving this cutting step (S100); First bending step (S200) of forming the semi-finished products of the first to third inner frame (110a, 110b, 110c) and the fourth inner frame (110d), respectively; A second bending step (S300) of forming the semi-finished products of the first to third outer frames 120a, 120b, and 120c and the fourth outer frame 120d, respectively; A third bending step (S400) of forming the first to third inner frames 110a, 110b and 110c and the first to third outer frames 120a, 120b and 120c; And a coupling step (S500) for forming a fourth frame member (100d).

Filter, medium filter, pre-filter, frame, bending machine, press, galvanized steel sheet

Description

Filter frame and manufacturing method thereof

The present invention relates to a filter frame for supporting air filters used in various air conditioners and a method of manufacturing the same, and more particularly, by pressing the inner frame and the outer frame for accommodating the medium filter and the prefilter without welding, The present invention relates to a filter frame and a method of manufacturing the same, which can be quickly bonded to greatly improve productivity and increase durability and airtightness.

An air filter (hereinafter referred to as a `` filter '') is installed in the air conditioning facilities of general buildings and clean rooms of various industrial sites to remove the dust, impurities, and bacteria in the air and supply the purified air to the room. do. Representative types of filters include a pre filter that primarily filters air dust and the like, and a medium filter that filters fine dust and the like that pass through the prefilter.

The prefilter and the medium filter are generally accommodated in a frame-type filter frame and installed in a fixed frame pre-installed in the air conditioner. As such, since the filter frames of the prefilter and the medium filter are separately manufactured, there is a problem in that the manufacturing and installation costs are high. In order to solve this problem, there is an integrated filter frame manufactured to accommodate the prefilter and the medium filter at the same time.

1 is an exploded perspective view for explaining a process of manufacturing a filter frame according to the prior art. As shown in FIG. 1, the conventional integrated filter frame 200 includes an inner frame 210a, 210b, 210c, and 210d that are largely supported by a medium filter (not shown) and an outer frame that is supported by a prefilter (not shown). 220a, 220b, 220c, and 220d.

The conventional method of manufacturing the integrated filter frame 200 is as follows. First, the first to third inner frames 210a, 210b and 210c and the first to third outer frames 220a, 220b and 220c as shown in FIG. ), The fourth inner frame 210d and the fourth outer frame 220d are formed. Then, the first to third inner frame (210a, 210b, 210c) and the first to third outer frame (220a, 220b, 220c) by spot welding (spot welding) to the first to third frame member (200a) , 200b, 200c. Similarly, the fourth inner frame 210d and the fourth outer frame 220d are joined by spot welding to make the fourth frame member 200d. A medium filter (not shown) is inserted into the inner frames 210a, 210b, and 210c of the first to third frame members 200a, 200b, and 200c, and a prefilter (outside) is provided to the outer frames 220a, 220b, and 220c. Not shown). Then, the medium filter (not shown) and the pre-filter (not shown) are fastened by coupling the fourth frame member 200d to the first and third frame members 200a and 200c by spot welding.

As described above, in the conventional integrated filter frame 200, the inner frames 210a, 210b, 210c, and 210d and the outer frames 220a, 220b, 220c, and 220d are joined by spot welding. However, since spot welding is performed by manpower, it takes a lot of manufacturing time and manufacturing cost, and thus, the productivity of the filter frame 200 is greatly reduced.

In addition, since the inner frame (210a, 210b, 210c, 210d) and the outer frame (220a, 220b, 220c, 220d) is sparse spot welding, the durability is weak, and air that is not sufficiently filtered through the unwelded space flows out. There is a problem that it is easy.

The present invention is to solve the above problems, an object of the present invention is to improve the productivity by quickly combining the inner frame and the outer frame to accommodate the medium filter and the pre-filter respectively, and excellent durability and airtight filter frame and It is to provide a manufacturing method.

An object of the present invention as described above, the inner frame 110 for supporting one side end of the medium filter 20, and is formed extending in the front outer side of the inner frame 110, one side end of the prefilter 30 In the manufacturing method of the filter frame having the first to fourth frame members (100a, 100b, 100c, 100d) consisting of the outer frame 120 for supporting, the first to third frame members (100a, 100b, 100c) The inner and outer frames 110a, 110b, and 110c and the outer and outer frames 120a, 120b, and 120c of the first and second metal plates cut in a predetermined shape, respectively, and the inner frame of the fourth frame member 100d ( Cutting step (S100) for preparing a third and fourth metal plate cut in a predetermined shape to manufacture 110d) and the outer frame (120d), respectively; One end of the first and the third metal plate member is bent 120 ° or more to form the first connecting piece 118 (S210), and 90 ° bent from the first connecting piece 118 by a predetermined length to bend the prefilter. Forming a first pre-filter guide 116 which is in contact with the rear surface of the (30) (S220), the other ends of the first and third metal plate bent by 90 ° to contact one side of the medium filter 20 Semi-finished products of the first to third inner frames 110a, 110b, and 110c are formed by forming an inner plate 112 and a medium filter guide 114 in contact with the rear surface of the medium filter 20. First bending step (S200) for forming each of the four inner frame (110d); One end of the second and fourth metal plate members are bent by 120 ° or more to form the second connecting piece 126 (S310), and the spaced apart from the second connecting piece 126 by a predetermined length by 90 ° to form a gasket. Forming the guide 124 (S320), the other end of the second and fourth metal plate material by bending the 90 ° to the outer plate 122 and the pre-filter 30 to be in contact with one side of the pre-filter 30 Forming a second prefilter guide 128 which is in contact with the front surface of the first and third outer frames 120a, 120b, and 120c and forming a fourth outer frame 120d, respectively. Second bending step S300; The semi-finished products of the first to third inner frames 110a, 110b, and 110c and the semi-finished products of the first to third outer frames 120a, 120b, and 120c are bent in a U-shape to form the first to third inner frames 110a, A third bending step (S400) forming 110 b and 110 c and first to third outer frames 120 a, 120 b and 120 c; And a first connection piece 118 of the first to third inner frames 110a, 110b, and 110c and a second connection piece 126 of the first to third outer frames 120a, 120b, and 120c. The third frame members 100a, 100b, and 100c are formed, and the first connecting piece 118 of the fourth inner frame 110d and the second connecting piece 126 of the fourth outer frame 120d are coupled to each other to form a fourth frame. It can be achieved by a method of manufacturing a filter frame comprising a; coupling step (S500) to form a member (100d).

In addition, the method of manufacturing a filter frame according to the present invention includes the first to third inner frames 110a, 110b, and 110c and the first to third outer frames 120a, 120b, and 120c after the coupling step S500. The medium filter 20 and the prefilter 30 are respectively inserted in sequence, and the filter receiving step S600 is characterized in that the fourth frame member 100d is coupled to the first and third frame members 100a and 100c. It may further include.

In addition, the coupling step (S530) is characterized in that the first pre-filter guide 116 and the gasket guide 124 by pressing the plastic deformation of the first connection piece 118 and the second connection piece 126.

In addition, it is preferable that the 1st-4th metal plate material is a galvanized steel sheet.

In addition, the first bending step S200 further includes forming a third connection piece 119 bent inward by 90 ° on both ends of the inner side plate 112 of the fourth inner frame 110d (S240). The second bending step S300 further includes forming a fourth connection piece 129 bent inward by 90 ° at both ends of the outer plate 122 of the fourth outer frame 120d (S340).

On the other hand, the object of the present invention as described above, each of the first to third inner frame (110a, 110b, 110c) and the first to the third outer frame (120a, 120b, 120c) is bent in a U-shape formed integrally And the fourth inner frame 110d and the fourth outer frame 120d are combined to form the first to fourth frame members 100a, 100b, 100c, and 100d on each side. 3 inner frame (110a, 110b, 110c) and the fourth inner frame (110d) is bent inward 90 ° from the rear end of the inner plate 112 and the inner plate 112 in contact with one side of the medium filter 20 A medium filter guide 114 in contact with the rear surface of the medium filter 20, a first prefilter guide 116 bent 90 degrees outward from the front end of the inner plate 112 and in contact with the rear surface of the prefilter 30, The first connecting piece 118 is bent from the end of the first pre-filter guide 116, the first to third outer frame (120a, 120b, 120c) and the first 4, the outer frame 120d includes an outer plate 122 in contact with one side of the prefilter 30, a gasket guide 124 bent inward from the rear end of the outer plate 122, and a gasket guide ( The second connecting piece 126 is bent from the end of the 124 and coupled to the first connecting piece 118 and the second pre-bending 90 ° from the front end of the outer plate 122 to contact the front surface of the prefilter 30. The filter guide 128, the inner frame (110a, 110b, 110c, 110d) and the outer frame (120a, 120b, 120c, 120d) is the first connecting piece 118 and the second connecting piece 126 is a press It can also be achieved by the filter frame 10, characterized in that coupled by pressing and plastic deformation.

In addition, the fourth frame member 100d includes a third connecting piece 119 and a fourth connecting piece 129 formed on the inner side plate 112 and the outer side plate 122 of the first and third frame members 100a and 100c, respectively. Rivet or bolted.

In addition, the outer frame (120a, 120b, 120c, 120d) further includes a gasket 130 bonded to the rear side of the gasket guide (124).

As described above, the manufacturing method of the filter frame according to the present invention can quickly combine the inner frame and the outer frame by pressing the first connecting piece and the second connecting piece bent to the inner frame and the outer frame with a plastic deformation. have. This has the advantage that the manufacturing cost of the filter frame is significantly reduced compared to the method of coupling by welding.

In addition, the filter frame according to the present invention has the advantage that the durability and airtightness is greatly increased because the first connecting piece and the second connecting piece is hermetically coupled along the circumference of the first to fourth frame member. In addition, since the fourth frame member may be coupled to the first to third frame members by rivets or bolts, there is an advantage in that the medium filter and the prefilter can be fastened.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it will be readily apparent to those skilled in the art that various other modifications and variations are possible without departing from the spirit and scope of the invention. Are all within the scope of the appended claims.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to components of each drawing, the same reference numerals are used for the same components as much as possible even if they are shown in different drawings.

[Manufacturing Method of Filter Frame]

First, with reference to the accompanying drawings looks at the manufacturing method of the filter frame according to an embodiment of the present invention.

2 is a flowchart illustrating a method of manufacturing a filter frame according to an embodiment of the present invention, FIG. 3 is a flowchart illustrating a first bending step S200 of FIG. 2, and FIG. 4 is a second bending step of FIG. 2 ( S300). As shown in FIG. 2, the method for manufacturing the filter frame according to the present embodiment includes a cutting step S100, a first bending step S200, a second bending step S300, a third bending step S400, and a coupling step. S500 and the filter accommodation step S600 are sequentially performed. In this case, a bending machine is used in the first to third bending steps S200, S300, and S400, and a press is used in the coupling step S500.

Cutting step (S100) is to manufacture the inner frame (110a, 110b, 110c) and the outer frame (120a, 120b, 120c) of the first to third frame members (100a, 100b, 100c), respectively, as shown in FIG. In order to prepare a first and a second metal plate (not shown) cut in a predetermined shape. In order to manufacture the inner frame 110d and the outer frame 120d of the fourth frame member 100d, the third and fourth metal sheets cut in a predetermined shape are prepared. At this time, the metal plate is preferably a galvanized steel sheet excellent in corrosion resistance and strength, it may be a plate made of stainless steel, aluminum alloy and the like.

In the first bending step S200, the semi-finished products and the fourth inner frame 110d of the first bet third inner frames 110a, 110b and 110c are respectively bent by bending the first and third metal sheets cut using a bending machine. Are manufactured. First, first ends of the first and third metal plate members are bent by 120 ° or more to form the first connecting pieces 118 (S210). Then, the spaced apart from the first connecting piece 118 by a predetermined length by 90 ° to form a first prefilter guide 116 to be in contact with the rear surface of the prefilter 30 (S220). Then, the other end portion of the first and the third metal plate member is bent by 90 ° so as to contact the inner plate 112 and the rear surface of the medium filter 20 to be in contact with one side of the medium filter 20. To form (S230). At this time, the third metal plate member further bends both ends of the inner plate 112 inward by 90 ° to further form the third connecting piece 119 of the fourth inner frame 110d (S240).

In the second bending step S300, the semi-finished products of the first to third outer frames 120a, 120b, and 120c and the fourth outer frame 120d are respectively bent by bending the cut second and fourth metal sheets using a bending machine. Are manufactured. First, one ends of the second and fourth metal plate members are bent by 120 ° or more to form the second connecting pieces 126 (S310). Then, the spaced apart from the second connecting piece 126 by a predetermined length by 90 ° to form a gasket guide 124 to which the gasket 130 is bonded (S320). In addition, the second end of the second and fourth metal plate members is bent by 90 ° to contact the one side of the prefilter 30 and the second prefilter guide that comes into contact with the front surface of the prefilter 30 ( 128) (S330). At this time, the fourth metal plate member further bends both ends of the outer plate 122 inward to form an additional fourth connecting piece 129 of the fourth outer frame 120d (S240).

The third bending step (S400) is the first to third inner frame (110a, 110b, 110c) and the first to third outer frame (120a, 120b) manufactured in the first and second bending step (S200, S300), respectively , The first to third inner frame (110a, 110b, 110c) and the first to the third outer frame (120a, 120b, 120c) is manufactured by bending the semi-finished product of the 120c, as shown in FIG. do.

Coupling step (S500) is made by combining the first to third inner frame (110a, 110b, 110c) and the first to third outer frame (120a, 120b, 120c) manufactured in the third bending step (S400) First to third frame members 100a, 100b, and 100c are manufactured. In addition, the fourth frame member 100d is manufactured by combining the fourth inner frame 110d and the fourth outer frame 120d manufactured in the second bending step S300. Looking at the coupling process in detail, in the case of the first to third frame members (100a, 100b, 100c), as shown in Figure 5 the second connecting piece 126 of the first to third outer frame (120a, 120b, 120c) ) Is inserted in the direction of the arrow so as to be located between the first prefilter guide 116 and the first connecting piece 118 of the first to third inner frame (110a, 110b, 110c). As shown in FIG. 7, when the first prefilter guide 116 and the gasket guide 124 are pressed by a press, the first connection piece 118 and the second connection piece 126 are plastically deformed. At this time, the first connecting piece 118 and the second connecting piece 126 are staggered and fixed to each other, thereby forming the first to third frame members 100a, 100b, and 100c. The fourth frame member 100d is also formed by this process.

Filter receiving step (S600) is the first to third inner frame (110a, 110b, 110c) and the first to third outer frame (120a, 120b) of the manufactured first to third frame member (100a, 100b, 100c) Medium filters 20 and prefilters 30 are sequentially inserted into 120c, respectively. The medium filter 20 and the prefilter 30 are fastened by coupling the fourth frame member 100d to the first and third frame members 100a and 100c. In this case, the fourth frame member 100d may include the third connecting piece 119 and the fourth connecting piece 129 formed at both ends of the inner plate 112 and the outer plate 122, respectively. By riveting to the inner side plate 112 and the outer side plate 122 of, 100c, respectively, the filter 20, 30 can be accommodated quickly.

[Filter frame]

Hereinafter, it looks at with respect to the filter frame according to an embodiment of the present invention manufactured by the above-described manufacturing method.

5 is an exploded perspective view showing a filter frame according to an embodiment of the present invention, Figure 6 is a combined perspective view showing a filter installed in the filter frame according to an embodiment of the present invention, Figure 7 is AA of Figure 6 "Is a cross-sectional view. The filter frame 10 according to an embodiment of the present invention has a frame shape as shown in FIG. The filter frame 10 according to the embodiment of the present invention is bent to form a large c-shape each as shown in Figure 5, the first to third inner frame (110a) 110b and 110c, and first to third outer frames 120a, 120b and 120c, and a fourth inner frame 110d and a fourth outer frame 120d.

The first to fourth inner frames 110a, 110b, 110c, and 110d each have a bent structure including an inner plate 112, a medium filter guide 114, a first prefilter guide 116, and a first connecting piece 118. Has The inner plate 112 has a width corresponding to the thickness of the medium filter 20 to be in contact with one side of the medium filter 20. The medium filter guide 114 is bent by 90 degrees from the rear end of the inner plate 112 to the inside. The medium filter guide 114 is in contact with the rear surface of the medium filter 20, and supports the medium filter 20 together with the inner plate 112. In addition, the first prefilter guide 116 is bent 90 degrees outward from the front end of the inner plate 112 and comes into contact with the rear surface of the prefilter 30. The first connecting piece 118 is bent from the end of the first prefilter guide 116 to form 20 ° to 60 ° with the first prefilter guide 116. In addition, the fourth inner frame 110d further includes third connecting pieces 119 disposed inwardly at both ends of the inner plate 112.

The first to fourth outer frames 120a, 120b, 120c, and 120d each have a bending structure including an outer plate 122, a gasket guide 124, a second connecting piece 126, and a second prefilter guide 128. Has The outer plate 122 has a width corresponding to the thickness of the prefilter 20 to be in contact with one side of the prefilter 20. The gasket guide 124 is bent 90 degrees from the rear end of the outer plate 122 to the inside, and the gasket 130 is joined to the rear side of the gasket guide 124. The second connecting piece 126 is bent from the end of the gasket guide 124 and is coupled to the first connecting piece 118. The second prefilter guide 128 is bent by 90 ° from the front end of the outer plate 122 to be in contact with the front surface of the prefilter 30. The fourth outer frame 120d further includes a fourth connecting piece 129 bent inward by 90 ° at both ends of the outer plate 122.

Meanwhile, the first connection piece 118 and the second connection piece 126 described above are pressed by a press and plastically deformed as shown in FIG. 7, thereby forming the first to fourth inner frames 110a, 110b, 110c, and 110d and The first to fourth outer frames 120a, 120b, 120c, and 120d are coupled to each other. In this case, the first connecting piece 118 and the second connecting piece 126 are hermetically coupled along the circumferences of the first to fourth frame members 100a, 100b, 100c, and 100d, thereby providing durability and airtightness of the filter frame 10. Is increased.

In addition, in the fourth frame member 100d, the third connecting piece 119 and the fourth connecting piece 129 may be formed on the inner side plate 112 and the outer side plate 122 of the first and third frame members 100a and 100c, respectively. By riveting or bolting, the first to third frame members 100a, 100b and 100c and the fourth frame member 100d can be quickly coupled. Therefore, the medium filter and the prefilter can be accommodated quickly. In addition, the third connecting piece 119 and the fourth connecting piece 129 may be spot welded.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it will be readily apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention, and all such changes and modifications are It is obvious that it belongs to the scope of the appended claims.

1 is an exploded perspective view for explaining a process of manufacturing a filter frame according to the prior art.

2 is a flow chart showing a method of manufacturing a filter frame according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a first bending step S200 of FIG. 2.

4 is a flowchart illustrating a second bending step S300 of FIG. 2.

5 is an exploded perspective view showing a filter frame according to an embodiment of the present invention.

6 is a perspective view showing a filter installed in the filter frame according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view taken along line AA ′ of FIG. 6;

<Description of the symbols for the main parts of the drawings>

10 filter frame 20 medium filter

30: prefilter 40: rivet

100a, 100b, 100c, 100d: first to fourth frame members

110a, 110b, 110c, and 110d: first to fourth inner frames

112: inner plate 114: medium filter guide

116: first prefilter guide 118: first connecting piece

119: third connecting piece

120a, 120b, 120c, and 120d: first to fourth outer frames

122: outer plate 124: gasket guide

126: second connecting piece 128: second prefilter guide

129: fourth connecting piece 130: gasket

Claims (8)

To the inner frame 110 for supporting one side end of the medium filter 20, and the outer frame 120 extending to the front outer side of the inner frame 110 to support one side end of the pre-filter (30) In the manufacturing method of the filter frame provided with the first to fourth frame members (100a, 100b, 100c, 100d), First and second cut to a predetermined shape to manufacture the inner frame (110a, 110b, 110c) and the outer frame (120a, 120b, 120c) of the first to third frame member (100a, 100b, 100c), respectively A cutting step (S100) of preparing a metal plate and third and fourth metal plates cut in a predetermined shape to manufacture the inner frame 110d and the outer frame 120d of the fourth frame member 100d, respectively; One end of the first and the third metal plate is bent by 120 ° or more to form a first connecting piece 118 (S210), and a 90 ° bent from the first connecting piece 118 by a predetermined length. Forming a first prefilter guide 116 which is in contact with a rear surface of the prefilter 30 (S220), and bending the other ends of the first and third metal plates by 90 ° to form the medium filter 20. The first to third inner frames 110a and 110b may be formed by forming an inner plate 112 which is in contact with one side of the medium and a medium filter guide 114 which is in contact with the rear surface of the medium filter 20. A first bending step (S200) of forming a semi-finished product of (110c) and the fourth inner frame (110d), respectively; One end of the second and fourth metal plate member is bent by 120 ° or more to form a second connection piece 126 (S310), and 90 ° by bending a spaced apart from the second connection piece 126 by a predetermined length. Forming a gasket guide 124 (S320), and the outer side plate 122 and the other side of the pre-filter 30 to bend the other end of the second and fourth metal plate material by 90 ° Forming a second prefilter guide 128 in contact with the front surface of the prefilter 30 (S330) consists of the semi-finished products of the first to third outer frame (120a, 120b, 120c) and the fourth outer frame A second bending step S300 for forming 120d, respectively; The semi-finished products of the first to third inner frames (110a, 110b, 110c) and the semi-finished products of the first to third outer frames (120a, 120b, 120c) are respectively bent in a U-shape to form the first to third inner frames. A third bending step (S400) of forming (110a, 110b, 110c) and the first to third outer frames (120a, 120b, 120c); And The first connection piece 118 of the first to third inner frames 110a, 110b, and 110c and the second connection piece 126 of the first to third outer frames 120a, 120b, and 120c are coupled to each other to form the first connection piece 126. 1 to 3 frame members 100a, 100b, and 100c are formed, and the first connecting piece 118 of the fourth inner frame 110d and the second connecting piece 126 of the fourth outer frame 120d are coupled to each other. By combining step (S500) to form the fourth frame member (100d) by the manufacturing method of the filter frame comprising a. The method of claim 1, After the coupling step (S500), the medium filter 20 and the free in the first to third inner frame (110a, 110b, 110c) and the first to third outer frame (120a, 120b, 120c), respectively Inserting the filter 30 in sequence, and further comprising a filter receiving step (S600), characterized in that for coupling the fourth frame member (100d) to the first and third frame members (100a, 100c). The manufacturing method of the filter frame made into. The method of claim 1, The coupling step (S500) is characterized in that the first pre-filter guide 116 and the gasket guide 124 by pressing to plastic deformation of the first connecting piece 118 and the second connecting piece 126. The manufacturing method of the filter frame made into. The method of claim 1, The metal plate material is a manufacturing method of the filter frame, characterized in that the galvanized steel sheet. The method of claim 1, The first bending step S200 further includes forming a third connection piece 119 bent inward by 90 ° on both ends of the inner side plate 112 of the fourth inner frame 110d (S240). The second bending step S300 may further include forming a fourth connection piece 129 bent inward by 90 ° on both ends of the outer plate 122 of the fourth outer frame 120d (S340). The manufacturing method of the filter frame made into. Each of the first to third inner frames 110a, 110b, and 110c and the first to third outer frames 120a, 120b, and 120c, and the fourth inner frame 110d and the first, which are bent to form a U-shape, are integrally formed. In the filter frame in which the outer frame 120d is coupled to form the first to fourth frame members 100a, 100b, 100c, and 100d on each side, The first to third inner frames 110a, 110b and 110c and the fourth inner frame 110d may include an inner plate 112 contacting one side of the medium filter 20 and a rear end of the inner plate 112. A medium filter guide 114 that is bent 90 ° from the inside to be in contact with the rear surface of the medium filter 20, and is bent 90 ° outward from the front end of the inner plate 112 to be in contact with the rear surface of the prefilter 30. 1 comprises a prefilter guide 116 and a first connecting piece 118 bent from an end of the first prefilter guide 116, The first to third outer frames 120a, 120b and 120c and the fourth outer frame 120d may include an outer plate 122 contacting one side of the prefilter 30 and an outer plate 122. A gasket guide 124 bent inward from a rear end by 90 °, a second connecting piece 126 bent from an end of the gasket guide 124 and coupled to the first connecting piece 118, and the outer plate ( It is made of a second pre-filter guide 128 is bent 90 ° from the front end of the 122 to contact the front surface of the pre-filter 30, The inner frame (110a, 110b, 110c, 110d) and the outer frame (120a, 120b, 120c, 120d) is coupled by pressing the first connecting piece 118 and the second connecting piece 126 by plastic deformation by pressing The filter frame characterized by the above-mentioned. The method of claim 6, The fourth frame member 100d has the third connecting piece 119 and the fourth connecting piece 129 having an inner side plate 112 and an outer side plate 122 of the first and third frame members 100a and 100c. Filter frames, characterized in that each of which is riveted, bolted or welded. The method of claim 6, The outer frame (120a, 120b, 120c, 120d) is a filter frame further comprises a gasket (130) bonded to the rear side of the gasket guide (124).

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