JP2017127849A - Dust-proof filter and water-proof/dust-proof scale equipped with same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust-proof filter in which a substantial area of a porous film is enlarged with no enlargement in an area of fitting to a housing.SOLUTION: A dust-proof filter, which is located in a pore of a wall which partitions an outside space and an inside space, has: a communication space which exists in the inside space, is communicated with the inside space via porous films 301, 302, 401, 402 and is communicated with the outside space directly; tubular members 61, 62 which are interposed between an opening 213 facing the pore of the wall and the communication space, and which communicate the communication space with the outside space; and a porous film 22 which blocks the portion of the pore excluding the opening 213. The porous films 301, 302, 401, 402 of the communication space and the porous film 22 facing the outside space are located in a multilayer with a gap therebetween. A gas in the outside space and the inside space is flown in/out via plural porous films 22, 301, 302, 401, 402 located in the multilayer, and therefore, function of adjusting a difference between an inside pressure and an outside pressure can be enhanced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a dustproof filter installed in a hole or the like of a housing wall that separates an outer space and an inner space, and a waterproof dustproof scale including the dustproof filter, and substantially increases the area of the dustproof filter without changing the area of the hole. Thus, the function of adjusting the pressure difference between the inside and outside of the dustproof filter that improves the pressure difference between the outer space and the inner space of the wall is enhanced.

In Patent Document 1 shown below, as shown in FIG. 14, a through hole 51 is provided in an inclined surface 125 formed by recessing a part of the bottom of the lower housing 124, and this hole is closed with a nonwoven fabric filter 55. A waterproof dustproof balance is described in which a chamber 52 connected to a through hole 51 is closed with a porous film 54.
In the waterproof and dustproof balance, the upper housing 121 and the lower housing 124 are airtightly coupled, and as shown in FIG. 15 (a view of the balance taken from directly above with the weighing pan and the pan base removed), the weighing pan A diaphragm 57 is connected to a load receiving portion 56 that transmits a load applied to the housing and is displaced up and down in the housing, and the opening of the upper housing that is opened to allow the load transmitting mechanism to pass is hermetically closed by the diaphragm 57. It is.

  As the porous film 54, for example, a film made of a tetrafluoroethylene resin having several hundred million micropores per square centimeter is used. The hole diameter of the fine holes is several μm or less. This membrane is waterproof, dustproof, and breathable, prevents dust from entering the housing, and when the load is placed on the weighing pan, it compresses the measurement space that is compressed as the diaphragm deforms. When air is released from the housing and the load is removed from the weighing pan, the outside air pressure is supplied to the measurement space that becomes negative pressure as the diaphragm returns, and the difference between the inside and outside air pressure between the inside and outside of the housing Is solved.

  On the other hand, the nonwoven fabric filter 55 is formed by combining synthetic resin fibers, carbon fibers, glass fibers, metal fibers, or ceramic fibers with a binder into a cloth shape, and is several times as large as the porous film 54. To have several tens of times more voids. The nonwoven fabric filter 55 prevents the pores of the porous film 54 from being clogged when the scale is used at a site where oil mist or powder is generated. The non-woven fabric filter 55 contaminated with oil mist or powder is replaced with a new one.

Japanese Patent No. 5065178

Dust-proof filters that use porous membranes that are both waterproof and dust-proof and breathable are widely used not only in scales but also in automobile parts, mobile phones, office automation equipment, home appliances, etc. .
However, if the ability to adjust the internal / external air pressure difference of the porous membrane is low, it takes a lot of time to eliminate the internal pressure fluctuation, and the scale cannot quickly perform accurate measurement. Even if the weighing block of the scale body is improved so that the number of displayed digits of the load is increased by one digit, it will take time for the displayed value to stabilize if the internal / external pressure adjustment function of the dustproof filter cannot catch up. In addition, the display value flickers when the pressure in the measurement chamber changes due to the opening / closing of a door or the like.

Since the ventilation performance of the porous membrane depends on the diameter of the micropores through which the gas passes, increasing the micropore diameter improves the internal and external pressure adjustment function of the porous membrane. I can't.
Also, if the area of the porous membrane is increased, the internal / external pressure adjustment function can be improved. However, if the porous membrane housing attachment area is expanded, the housing structure must be enlarged, and the existing product can be expanded. The inconvenience that it cannot be attached arises.

  The present invention was devised in view of such circumstances, and provides a dustproof filter that can substantially expand the area of the porous membrane without expanding the mounting area to the housing, etc. It aims at providing the waterproof dustproof balance using it.

The present invention is arranged in a hole in the wall that separates the outer space and the inner space, and allows the inflow and outflow of gas between the outer space and the inner space, and prevents the inflow of dust from the outer space to the inner space. A dust-proof filter provided with a porous film that is disposed inside one space (for example, the inner space) of the inner space or the outer space, and one space (for example, the inner space) is a porous film The communication space is interposed between a communication space that directly communicates with the other space (for example, the outer space) of the inner space or the outer space, and an opening that faces the hole of the wall and the communication space. A tubular member that communicates directly with the other space (for example, the outer space), and a porous membrane facing the other space (for example, the outer space) that blocks the portion of the hole except the opening, and is a communication space. Porous membrane and porous facing the other space (eg outer space) And the film is arranged in multiple layers at a gap, and wherein the.
In this dustproof filter, the gas in the outer space and the inner space flows in and out through a plurality of porous films arranged in multiple layers, so that the internal / external air pressure difference adjustment function is improved.

In the dustproof filter of the present invention, the communication space includes two parallel porous membranes and a frame that forms a communication space while maintaining a distance between the two porous membranes.
Therefore, for example, if one communication space exists in the inner space, two porous films that contribute to the adjustment of the internal / external air pressure difference are increased.

In the dustproof filter of the present invention, a plurality of communication spaces may be arranged in multiple layers with a space between each other in one space (for example, the inner space).
For example, when a plurality of communication spaces are arranged in the inner space, the porous membrane + (number of communication spaces × 2) porous membranes facing the outer space contributes to the adjustment of the internal / external pressure difference.

In the dustproof filter of the present invention, the tubular member maintains a gap between the communication spaces arranged in multiple layers and a gap between the communication space and the porous membrane facing the other space (for example, the outer space). It also serves as a spacer, and this spacer has a through hole for communication.
Spacers are arranged between the porous membrane facing the outer space and the communication space, and between the communication space and the communication space thereabove, and the communication space communicates with the external space through the through hole of the spacer.

Further, in the dustproof filter of the present invention, the porous membrane fixes one surface of the first frame having a frame portion for fixing the porous membrane and a spacer fixing portion for fixing the spacer, or the porous membrane. The spacer is fixed to one surface of the second frame having only a frame portion, and the spacer has one surface of the spacer fixing portion so that the hole formed in the spacer fixing portion of the first frame matches the through hole of the spacer. Fixed to.
The communication space of the outermost layer of the communication space arranged in multiple layers includes a first frame to which the porous membrane is fixed and a second frame to which the porous membrane is fixed. The one or more communication spaces, which are configured to overlap each other so as to be located outside the communication space and are positioned in the middle of the communication spaces arranged in multiple layers, include a first first frame to which a porous membrane is fixed, The second frame to which the porous membrane is not fixed and the second first frame to which the porous membrane is fixed are overlapped so that the two porous membranes are located outside the communication space. The porous film facing the other space (for example, the outer space) is fixed to one surface of the first frame, and the other surface of the first frame is fixed to the periphery of the hole.
Therefore, the hole of the spacer fixing portion of the first frame to which the porous film facing the outer space is fixed becomes an opening to the outer space, and the first communication space is formed through the through hole of the first spacer communicating with the opening. The second communication space communicates with the outer space through the through hole of the second spacer that communicates with the outer space and communicates with the first communication space.

Further, in the dustproof filter of the present invention, the outer surface of the first frame protrudes to the wide first engaging piece that protrudes to one surface side of the first frame and the other surface side of the first frame. It has a locking part where the second engaging piece with a narrow width is raised, and a first fitting part having a gap in which the first engaging piece can be fitted, and the outer surface of the second frame is It has 1 or 2 2nd fitting parts provided with the gap | interval which can fit the 2nd engagement piece.
Then, one or two first frames and the second frame are overlapped to form a communication space so that the second engagement piece of the first frame and the second fitting portion of the second frame are fitted. The first engagement piece of the first frame and the first fitting portion of the other first frame are fitted to each other, or the communication spaces, or the porous space facing the communication space and the other space (for example, the outer space). The first frame to which the membrane is fixed is combined.
Therefore, a combination of the first frame and the second frame for configuring the communication space, a combination of the communication spaces, or a combination of the communication space and the first frame to which the porous membrane facing the outer space is fixed. Can be done without mistakes.

The waterproof and dustproof balance of the present invention includes the above dustproof filter in the hole of the housing.
The size of the hole provided in the housing of this balance is the same as that of the conventional housing, and the mounting area of the dustproof filter that is mounted so as to close the hole is the same as the conventional one. However, the number of porous membranes in the dustproof filter has increased, and the ability to adjust the difference between the internal and external air pressure has been enhanced.

The dustproof filter of the present invention can expand the area of the porous membrane without increasing the mounting area to the housing or the like, thereby improving the adjustment capability of the internal / external air pressure difference.
Moreover, since the waterproof and dustproof balance of the present invention includes this dustproof filter, accurate weighing can be performed quickly.

The perspective view of the dustproof filter concerning the embodiment of the present invention. Plan view (a), side view (b), back view (c) of the dustproof filter of FIG. The figure which shows the metal spacer used with the dustproof filter of FIG. The disassembled perspective view of the lower dustproof filter part in the dustproof filter of FIG. The disassembled perspective view of the intermediate | middle dustproof filter part in the dustproof filter of FIG. The figure explaining the engagement relationship of each flame | frame at the time of assembling the intermediate | middle dustproof filter part of FIG. 1 is an exploded perspective view of an upper dustproof filter portion in the dustproof filter of FIG. 1 is an exploded perspective view of the dust filter of FIG. The figure which shows the engaging part and fitting part which are provided in each flame | frame The figure which shows the engagement relationship of the engaging part and fitting part when assembling an upper dustproof filter part and an intermediate | middle dustproof filter part The figure which shows the engagement relation of an engaging part and a fitting part when connecting an upper dustproof filter part, an intermediate | middle dustproof filter part, and a lower dustproof filter part The figure which shows the state which attached the dustproof filter of FIG. 1 to the housing | casing of the balance. Sectional view of a waterproof dustproof balance with the dustproof filter of Fig. 1 Diagram showing a conventional waterproof and dustproof balance Diagram showing the structure of the waterproof dustproof scale near the diaphragm

FIG. 1 is a perspective view of a dust filter 10 according to an embodiment of the present invention. FIG. 2 (a) is a plan view of the dust filter, FIG. 2 (b) is a side view, and FIG. The figure is shown.
The dust filter 10 includes three layers of an upper dust filter unit 40, an intermediate dust filter unit 30, and a lower dust filter unit 20. As shown in FIG. 2B, a cylindrical metal spacer 62 is disposed between the upper dustproof filter unit 40 and the intermediate dustproof filter unit 30, and between the intermediate dustproof filter unit 30 and the lower dustproof filter unit 20. Are provided with metal spacers 61 of the same shape.
FIG. 3 shows the metal spacers 61 and 62. Cylindrical metal spacers 61 and 62 have a through hole in the center. Both end surfaces of the metal spacer 61 are fixed to the lower dustproof filter portion 20 and the intermediate dustproof filter portion 30 with an annular double-sided adhesive tape 63, and both end surfaces of the metal spacer 62 are similarly intermediately dustproofed with the double-sided adhesive tape 63. The filter unit 30 and the upper dustproof filter unit 40 are fixed.

As shown in FIG. 4, the lower dustproof filter section 20 includes a porous film 22, a rectangular frame section 211 to which the porous film 22 is fixed, and a spacer fixing section 212 to which the metal spacer 61 is fixed. (In this specification, a frame having a frame portion and a spacer fixing portion is referred to as a “first frame”).
The metal spacer 61 and the porous membrane 22 are fixed to the same surface of the first frame 21.
The spacer fixing portion 212 extends inside the frame portion 211 and has a hole 213 at the center thereof. The metal spacer 61 is fixed to the spacer fixing portion 212 with an annular double-sided adhesive tape 63 so that the central through hole thereof coincides with the hole 213.
A U-shaped cut is formed on the short side of the porous film 22 so as to avoid the metal spacer 61 fixed to the spacer fixing portion 212, and the periphery of the cut avoids the metal spacer 61 and is a spacer. It is fixed to the peripheral part of the fixing part 212 with a double-sided adhesive tape. The other edge of the porous membrane 22 is fixed to the frame portion 211 of the first frame 21 with a double-sided adhesive tape.
As a result, the opening bordered by the frame portion 211 and the spacer fixing portion 212 of the first frame 21 is closed by the porous film 22.

Further, on one of the short sides of the frame portion 211, a locking portion 70 in which a wide first engaging piece 71 and a narrow second engaging piece 72 are raised in the opposite direction on the outer surface thereof, A first fitting portion 81 including a pair of protrusions 811 and 812 protruding with a gap corresponding to the width of the first engagement piece 71 is provided. The first engagement piece 71 of the locking portion 70 protrudes to the porous film 22 fixing surface side of the first frame 21, and the second engagement piece 72 protrudes to the opposite surface side of the first frame 21. .
The first frame 21 is fixed to the periphery of the hole portion of the housing with the double-sided adhesive tape 23 so that the hole 213 of the spacer fixing portion 212 faces the hole portion.
The porous membrane 22 of the lower dustproof filter unit 20 faces the outer space of the housing, allows gas inflow / outflow between the outer space and the inner space of the housing, and extends from the outer space of the housing to the inner side. Prevent inflow of dust and water (excluding water vapor) into the space.
In addition, the dust contained in the gas in the outer space flowing in through the hole 213 of the spacer fixing portion 212 is prevented from flowing into the housing by the porous film of the intermediate dustproof filter portion 30 and the upper dustproof filter portion 40 described later.

As shown in FIG. 5, the intermediate dustproof filter unit 30 includes a first frame 31 to which the porous membrane 301 is fixed, and a frame 32 having only a frame portion 321 and no spacer fixing portion (in this specification, a frame 32). The frame having only the portion and not having the spacer fixing portion is referred to as a “second frame”), and the first frame 33 to which the porous membrane 302 is fixed.
The porous films 301 and 302 are the same as the porous film 22 in FIG. 4, and the first frames 31 and 33 are the same as the first frame 21 in FIG. One first frame 31 is arranged so that the fixed porous membrane 301 is on the lower side, and the other first frame 33 is arranged so that the fixed porous membrane 302 is on the upper side. Therefore, the narrow second engaging piece 72 of the locking portion 70 of the first frame 31 faces upward, and the second engaging piece 72 of the locking portion 70 of the first frame 33 faces downward.
A second fitting made of a pair of protrusions 821 and 822 (831 and 832) projecting with a gap corresponding to the width of the second engagement piece 72 on one of the short sides of the second frame 32. Two sets of portions 82 (83) are provided.

As shown in FIG. 6, the first frame 31 to which the porous membrane 301 is fixed has the second frame 32 so that the second engagement piece 72 is fitted to the second fitting portion 82 of the second frame 32. The first frame 33 coupled to the lower side and to which the porous membrane 302 is fixed has the second frame 32 such that the second engagement piece 72 is fitted to the second fitting portion 83 of the second frame 32. Is coupled to the upper side. The first frames 31 and 32 are each fixed to the second frame 32 with a double-sided adhesive tape.
Thereby, a space surrounded by the frame portions of the first frame 31, the second frame 32, and the first frame 33 is formed in the intermediate dustproof filter portion 30 between the porous membrane 301 and the porous membrane 302. The

Since the upper end of the metal spacer 61 coupled to the spacer fixing part 212 of the first frame 21 of the lower dustproof filter part 20 is fixed below the spacer fixing part 312 of the first frame 31, the intermediate dustproof filter part 30. Are formed in the spacer fixing part 212 of the first frame 21 of the lower dustproof filter part 20, the through hole of the metal spacer 61, and the spacer of the first frame 31 of the intermediate dustproof filter part 30. It communicates directly with the outer space through a hole 313 formed in the fixing portion 312. (In this specification, a space communicating with the outer space is referred to as a “communication space”.)
The porous membranes 301 and 302 of the intermediate dustproof filter unit 30 allow gas inflow and outflow between the communication space of the intermediate dustproof filter unit 30 and the inner space of the housing, and from the communication space of the intermediate dustproof filter unit 30. Prevents dust and water (excluding water vapor) from flowing into the inner space of the housing.

As shown in FIG. 7, the upper dustproof filter unit 40 includes a first frame 41 to which the porous film 401 is fixed and a second frame 42 to which the porous film 402 is fixed.
The porous membrane 401 is the same as the porous membrane 22 in FIG. 4, and the first frame 41 is the same as the first frame 21 in FIG. The second frame 42 is the same as the second frame 32 of FIG. Unlike the porous membrane 401, the outer shape of the porous membrane 402 fixed to the second frame 42 is rectangular. The porous film 402 is fixed to the second frame 42 with a double-sided adhesive tape.
The first frame 41 to which the porous membrane 401 is fixed has a second frame such that the second engagement piece 72 is fitted to the second fitting portion 84 of the second frame 42 to which the porous membrane 402 is fixed. 42 is connected to the lower side and fixed with double-sided adhesive tape.
Thereby, a space surrounded by the frame portions of the first frame 41 and the second frame 42 is formed in the upper dustproof filter portion 40 between the porous membrane 401 and the porous membrane 402.

Since the upper end of the metal spacer 62 coupled to the spacer fixing portion 332 of the first frame 33 on the upper side of the intermediate dustproof filter portion 30 is fixed to the lower side of the spacer fixing portion 412 of the first frame 41, the upper dustproof The space formed in the filter part 40 includes a hole 213 formed in the spacer fixing part 212 of the first frame 21 of the lower dustproof filter part 20, a through hole of the metal spacer 61, and the first frame 31 of the intermediate dustproof filter part 30. A hole 313 formed in the spacer fixing portion 312, a communication space of the intermediate dustproof filter portion 30, a hole 333 formed in the spacer fixing portion 332 of the first frame 33 of the intermediate dustproof filter portion 30, a through hole of the metal spacer 62, and The outer dust space is directly connected to the outer space through the hole 413 formed in the spacer fixing portion 412 of the first frame 41 of the upper dustproof filter portion 40. The communication space to be.
The porous membranes 401 and 402 of the upper dustproof filter unit 40 allow inflow and outflow of gas between the communication space of the upper dustproof filter unit 40 and the inner space of the housing, and from the communication space of the upper dustproof filter unit 40. Prevents dust and water (excluding water vapor) from flowing into the inner space of the housing.
The hole 213 formed in the spacer fixing part 212 of the first frame 21 of the lower dustproof filter part 20 communicates the communication space of the intermediate dustproof filter part 30 and the communication space of the upper dustproof filter part 40 to the outer space. It plays a role of opening.

  FIG. 8 shows a lower dust filter through a metal spacer 61 between the lower dust filter unit 20 and the intermediate dust filter unit 30 and a metal spacer 62 between the intermediate dust filter unit 30 and the upper dust filter unit 40. The mode when the part 20, the intermediate | middle dustproof filter part 30, and the upper dustproof filter part 40 are combined is shown. At this time, between the lower dustproof filter portion 20 and the intermediate dustproof filter portion 30, the wide first engaging piece 71 of the locking portion 70 protruding from the side surface of the lower dustproof filter portion 20 is the first of the intermediate dustproof filter portion 30. The intermediate dust-proof filter unit 30 is combined so that the first engagement piece 71 of the intermediate dust-proof filter unit 30 is fitted to the first fitting part 81 of the lower dust-proof filter unit 20. Between the upper dustproof filter part 40 and the upper dustproof filter part 40, the first engagement piece 71 of the intermediate dustproof filter part 30 is fitted into the first fitting part 81 of the upper dustproof filter part 40. The combination piece 71 is combined so as to fit into the first fitting portion 81 of the intermediate dustproof filter portion 30.

9, 10, and 11, the first engagement part 71 and the second engagement piece 72 of the engagement part 70 provided on the frame are provided with the first fitting part 81 and the second engagement part 71 provided on the other frame. The process by which the dustproof filter is assembled by being fitted to the fitting portion 82 is schematically shown.
FIG. 9 shows an engagement portion 70 and a first fitting portion 81 provided in each of the first frames 21, 31, 33, and 41, and a second fitting portion provided in each of the second frames 32 and 42. 82, 83.
In FIG. 10, the second engagement piece 72 of the first frames 31, 33 is fitted to the second fitting portions 82, 83 of the second frame 32 to assemble the intermediate dustproof filter portion 30. The state where the second engagement piece 72 is fitted to the second fitting portion 82 of the second frame 42 and the upper dustproof filter portion 40 is assembled is shown.

  In FIG. 11, the first engagement piece 71 of the lower dustproof filter part 20 is fitted to the first fitting part 81 of the intermediate dustproof filter part 30, and the first engagement piece 71 on the lower side of the intermediate dustproof filter part 30 is It is fitted to the first fitting part 81 of the lower dustproof filter part 20, the first engagement piece 71 on the upper side of the intermediate dustproof filter part 30 is fitted to the first fitting part 81 of the upper dustproof filter part 40, and upper dustproof The first engaging piece 71 of the filter unit 40 is fitted to the first fitting unit 81 on the upper side of the intermediate dustproof filter unit 30, and the lower dustproof filter unit 20, the intermediate dustproof filter unit 30, and the upper dustproof filter unit 40 are connected. The assembled state is shown.

Thus, this dustproof filter can be configured using two types of frames, the first frame and the second frame. Further, the engaging portion 70 and the fitting portions 81, 82, and 83 protrude from one of the short sides of these frames, and the first engaging piece 71 and the second engaging piece 72 of the engaging portion 70 By combining the first fitting portion 81 and the second fitting portion 82, a plurality of frames arranged in multiple layers can be assembled without making a mistake.
Further, since the engaging portion 70 and the fitting portions 81, 82, and 83 protrude only on one side of the frame, there is no possibility that the direction of the frame is mistaken during assembly work.

FIG. 12 shows a state in which the dustproof filter 10 is assembled to a waterproof dustproof balance, and FIG. 13 shows a sectional view of the waterproof dustproof balance.
The mounting area of the dustproof filter to the housing is the same as that of the conventional one shown in FIG. Increases by the number of porous membranes. Therefore, it is possible to carry out accurate weighing more quickly than in the past.
Here, although one intermediate dustproof filter unit 30 is provided between the upper dustproof filter unit 40 and the lower dustproof filter unit 20, the number of stages of the intermediate dustproof filter unit may be two or more. Also good.
In addition, the waterproof and dustproof balance referred to in this specification includes a waterproof balance and a dustproof balance.
Further, here, the case where the dustproof filter 10 is provided on the inner space side of the casing so as to close the hole of the casing has been described. However, the dustproof filter 10 is provided in the casing so as to close the hole of the casing. You may provide in the external space side.

  The dust-proof filter of the present invention can increase the area of the porous membrane by increasing the area of the porous film without increasing the mounting area to the housing, etc. It can be widely used for automobile parts, mobile phones, office automation equipment, home appliances, etc. that dislike internal pressure fluctuations.

DESCRIPTION OF SYMBOLS 10 Dustproof filter 20 Lower dustproof filter part 21 1st frame 22 Porous membrane 23 Double-sided adhesive tape 30 Intermediate dustproof filter part 31 1st frame 32 2nd frame 33 1st frame 40 Upper dustproof filter part 41 1st frame 42 2nd frame DESCRIPTION OF SYMBOLS 50 Weighing pan 51 Through-hole 52 Room 54 Porous membrane 55 Nonwoven fabric filter 56 Load receiving part 57 Diaphragm 61 Metal spacer 62 Metal spacer 63 Double-sided adhesive tape 70 Locking part 71 First engagement piece 72 Second engagement piece 81 First Fitting portion 82 Second fitting portion 83 Second fitting portion 84 Second fitting portion 121 Upper housing 124 Lower housing 125 Inclined surface 211 Frame portion 212 Spacer fixing portion 213 Hole 301 Porous membrane 302 Porous membrane 312 Spacer fixing portion 313 hole 321 frame portion 332 spacer fixing portion 333 401 porous membrane 402 porous membrane 412 spacer fixing portion 811 protruding pairs 821 and 822 projecting pairs 831 and 832 projecting pairs

Claims (7)

Arranged in the hole in the wall that separates the outer space and the inner space, allows the inflow and outflow of gas between the outer space and the inner space, and prevents the inflow of dust from the outer space to the inner space A dustproof filter provided with a porous film,
A communication space that is inside one of the inner space and the outer space and communicates with the one space via the porous membrane and directly communicates with the other space of the inner space or the outer space. When,
A tubular member interposed between the opening facing the hole and the communication space to directly communicate the communication space with the other space;
The porous membrane facing the other space blocking the portion of the hole except the opening;
Have
The porous membrane in the communication space and the porous membrane facing the other space are arranged in multiple layers with a gap between them,
A dustproof filter characterized by that.   The dust-proof filter according to claim 1, wherein the communication space includes two porous membranes in parallel and a frame that forms the communication space while maintaining a distance between the two porous membranes. A dustproof filter characterized by being configured.   3. The dust filter according to claim 1, wherein a plurality of the communication spaces are arranged in multiple layers with a space between each other in the one space. 4.   4. The dustproof filter according to claim 3, wherein the tubular member includes a gap between the communication spaces arranged in multiple layers, and a space between the communication space and the porous film facing the other space. A dustproof filter, which also serves as a spacer for maintaining a gap, and the spacer has a through hole for communication. The dust filter according to claim 4, wherein the porous film has one surface of a first frame having a frame part for fixing the porous film and a spacer fixing part for fixing the spacer, or The spacer is fixed to one surface of a second frame having only a frame portion for fixing the porous film, and the spacer has a hole formed in the spacer fixing portion of the first frame and a through hole of the spacer. Fixed to the one surface of the spacer fixing portion,
The communication space of the outermost layer of the communication space arranged in multiple layers includes the first frame to which the porous membrane is fixed and the second frame to which the porous membrane is fixed, the two porous It is configured to overlap so that the membrane is located outside the communication space,
One or a plurality of communication spaces located in the middle of the communication spaces arranged in multiple layers are the first first frame to which the porous membrane is fixed, and the second frame to which the porous membrane is not fixed. A frame and the second first frame to which the porous membrane is fixed are configured to overlap each other so that the two porous membranes are located outside the communication space.
The porous membrane facing the other space is fixed to one surface of the first frame, and the other surface of the first frame is fixed to the periphery of the hole.
A dustproof filter characterized by that. 6. The dust filter according to claim 5, wherein the outer surface of the first frame includes a wide first engaging piece projecting toward one surface of the first frame and the other surface of the first frame. A locking portion where a second engaging piece having a narrow width protruding to the side is raised, and a first fitting portion having a gap in which the first engaging piece can be fitted,
The outer surface of the second frame has one or two second fitting portions each having a gap in which the second engaging piece can be fitted,
The one or two first frames and the second frame are overlapped so that the second engagement piece of the first frame and the second fitting portion of the second frame are fitted to each other. A communication space is constructed,
Pores facing the communication spaces or the communication space and the other space by fitting the first engagement piece of the first frame and the first fitting portion of the other first frame. A dustproof filter, which is combined with the first frame to which a membrane is fixed.   A waterproof and dustproof balance comprising the dustproof filter according to any one of claims 1 to 6 in a hole of a housing.