JP2005313121A - Gas filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas filter having good filtration performance.
SOLUTION: A gas filter comprising a laminated body in which a plurality of wire meshes are laminated and deformed as necessary. The wire mesh constituting the laminated body includes a plurality of metal wires formed by intersecting a plurality of metal wires. It has convex intersections, and the adjacent metal meshes have any one of the following (A), (B), and (C), and the outer peripheral surface of the laminate does not appear uneven. Gas filter that is combined with the above.
(A) The wire diameters of the metal wires are different and the pitches between the convex intersections are different. (B) The wire diameters of the metal wires are different and the pitches between the convex intersections are the same. Are the same, but the pitch between convex intersections is different. [Selection figure] None

Description

  The present invention relates to a gas filter that can be used in an airbag inflator.

  In an air bag inflator, a filter is used for filtering and cooling a combustion gas residue. As the filter, a filter in which a plurality of wire meshes such as plain weave are laminated is used.

In a plain weave wire mesh 1 as shown in FIGS. 1A and 1B, vertical metal wires 2 and horizontal metal wires 3 are knitted alternately in the vertical and horizontal directions, and a convex shape is formed by the intersection of the metal wires 2 and 3. An intersection 4 exists. For this reason, when the metal meshes 1 (1a, 1b) having the same dimensions are laminated, the pitch (P ₁ ) between the two convex intersections 4 is the same, so that the convex shape as shown in FIG. Since the intersecting portions 4 come into contact with each other, the wire mesh 1 (1a, 1b) is actually stacked in a state shifted in the vertical or horizontal direction as shown in FIG.

  At this time, the convex intersection 4 of the wire mesh 1a enters between the two convex intersections 4 of the wire mesh 1b and becomes caught, so that it is difficult to slide in the length direction and it is difficult to align the ends. Become. For this reason, when the wire mesh is further laminated, the end face in the vertical or horizontal direction becomes an uneven surface.

Then, when a laminated body having an uneven end surface as shown in FIG. 2B is applied as a gas filter, there is a problem of a short path of gas from the end surface (a phenomenon in which gas flows without passing through the filter). However, it cannot function sufficiently as a filter.
USP 4,817,828

  FIG. 11 of Patent Document 1 discloses a filter for an airbag inflator in which a steel wool layer and a ceramic / glass wool layer are sandwiched between wire meshes, but the structure is complicated and the manufacturing cost is also low. Get higher.

  An object of the present invention is to provide a gas filter that is easy to manufacture and has high filtration performance.

The present invention is a gas filter comprising a laminate in which a plurality of wire meshes are laminated and deformed as necessary, as a means for solving the problems,
The wire mesh constituting the laminate has a plurality of convex intersections formed by intersecting a plurality of metal wires,
Adjacent wire meshes are slidable by having any one of the following relationships (A1), (B1), and (C1), and the plurality of wire meshes are uneven on the outer peripheral surface of the laminate. Gas filter that is combined so that it does not occur.
(A1) The wire diameters of the metal wires are different, and the pitches between the convex intersections are different;
(B1) The wire diameters of the metal wires are different and the pitch between the convex intersections is the same;
(C1) The wire diameter of the metal wire is the same, and the pitch between the convex intersections is different;
The pitch is the distance between the center of one convex intersection (metal line) and the center of the adjacent convex intersection (metal line).

  Examples of the wire mesh constituting the laminated body include plain weave, twill weave, plain tatami weave, twill tatami weave, etc., but depending on the use of the filter, weaves other than the above can also be used. . Furthermore, the metal mesh referred to in the present invention includes, for example, expanded metal and lath metal which are made into a net by cutting and stretching a mild steel sheet.

  If the laminate has any one of (A1), (B1), and (C1), for example, when 10 metal meshes are laminated, all the metal meshes are different. Alternatively, two different types of wire meshes may be alternately stacked, or 3 to 9 types of wire meshes may be stacked.

  Since the adjacent wire meshes are slidable by having any one of (A1), (B1), and (C1), they are shown in FIGS. 2 (a) and 2 (b). Such a problem does not occur.

  Furthermore, in the gas filter of the present invention, when the problem of the present invention is solved, adjacent wire meshes have a relationship of any one of the following (A2), (B2), and (C2). it can. (A2), (B2), and (C2) are obtained by adding an additional relationship to (A1), (B1), and (C1).

(A2) The wire diameters of the metal wires are different, the pitches between the convex intersections are different, and the distance between the convex intersections of one metal mesh is larger than the diameter of the convex intersection of the other metal mesh. Be a thing;
(B2) The wire diameters of the metal wires are different and the pitch between the convex crossing portions is the same, and the interval between the convex crossing portions of one wire mesh is larger than the diameter of the convex crossing portion of the other wire mesh. Is also large;
(C2) The wire diameter of the metal wire is the same, the pitch between the convex intersections is different, and the interval between the convex intersections of one metal mesh is larger than the diameter of the convex intersection of the other metal mesh. Be small;
In addition, the space | interval of the convex cross | intersection part of a metal-mesh is the space | interval between adjacent convex cross | intersection parts (however, the space | interval of the metal line of the part except a convex cross | intersection part).

  The gas filter of the present invention can be shaped according to the application, for example, cylindrical, U-shaped, box-shaped, or flat-plate shaped.

  The gas filter of the present invention can have an elastic filter material layer between the metal meshes constituting the laminate. Ceramic fiber, steel wool, glass wool, etc. can be used as the elastic filter medium.

  The gas filter of the present invention can be one in which part or all of the end face of the laminate is clamped and fixed from the viewpoint of facilitating adjustment of filtration performance, transportation and storage. .

  The gas filter of the present invention can be used as a filter for gas filtration in various fields, and is particularly suitable for high-temperature gas filtration. Specifically, it is suitable for a gas generator used for an air bag. .

When applied to a gas generator for an air bag, the gas filter of the present invention preferably has an overall pressure loss of 0.02 to 500 kPa at an air flow rate of 1 m ³ / min from the viewpoint of normal operation. More preferably, it is 0.05-30 kPa. The pressure loss is measured by the method disclosed in paragraph No. 67 of Japanese Patent No. 2,926,040 and FIG. Even when applied as a filter for other uses, it is set so as to maintain an appropriate pressure loss.

  The gas filter of the present invention can be easily incorporated into the apparatus and can exhibit excellent filtration performance without causing problems such as a short path. The gas filter of the present invention can be easily obtained from a laminate of a large number of sheets by using at least two types of wire mesh.

(1) First Embodiment A gas filter will be described with reference to FIGS. FIG. 1A is a plan view of a wire mesh, and FIG. 1B is a cross-sectional view of FIG. 1A, but is slightly simplified for easy understanding. FIG. 3 is a schematic cross-sectional view of the wire mesh, and illustrates the laminated state of the two wire meshes having the relationship of “(A1) different wire diameters and different pitches between the convex intersections” described above. It is a figure for doing.

  One metal mesh 1 is woven in a plain weave, in which vertical metal wires 2 and horizontal metal wires 3 are alternately woven, and convex intersections 4 are generated at the intersections. The vertical metal wire 2 and the horizontal metal wire 3 have the same diameter, but the diameter of the convex intersection 4 is larger than the diameter of the vertical metal wire 2 and the horizontal metal wire 3. In addition, since the cross-sectional shape of the convex intersection may not necessarily be a circle, the term “diameter of the convex intersection” below also includes the meaning of “the size of the convex intersection”.

  As shown in FIG. 3, a wire mesh 11 is laminated on the wire mesh 1. The vertical and horizontal dimensions of the metal mesh 11 and the metal mesh 1 are the same.

The diameter (D ₂ ) of the metal wire (lateral) 13 of the wire mesh 11 is larger than the diameter (D ₁ ) of the metal wire (lateral) 3 of the wire mesh 1, and the diameter of the convex intersection 14 is also that of the convex intersection 4. It becomes larger than the diameter.

The diameter (D ₃ ) of the convex intersection 14 is larger than the interval between adjacent convex intersections 4 (interval of only the metal wire 3 excluding the convex intersection 4) (w ₁ ) (D ₃ > It is preferable that it is equal to or greater than w ₁ ) and pitch P ₁ . When the relationship of D ₃ > w ₁ is satisfied, the convex intersection 14 does not fit between the two convex intersections 4 and does not become difficult to slide.

The pitch P ₂ between the convex intersections 14 is larger than the pitch P ₁ between the convex intersections 4. Note that all the pitch P ₂ between the convex cross section 14 is the same, the pitch P ₁ between the convex cross section 4 are all identical.

  When the metal mesh 11 is laminated on the metal mesh 1, the metal mesh 1 and the metal mesh 11 are slidable with each other because they have the relationship (A1). For this reason, the convex intersection 14 does not get stuck between the two convex intersections 4 and does not move. And since the vertical and horizontal dimensions of the wire mesh 11 and the wire mesh 1 are the same, it becomes easy to align the ends.

  Thus, by laminating the required number of sheets alternately in the order of the wire mesh 11 on the wire mesh 1, the wire mesh 1 on the wire mesh 11, and the wire mesh 11 on the wire mesh 1, finally the plate shape with the end faces aligned. The laminate can be easily obtained. Further, for example, in the case of laminating ten metal meshes, a method of arranging ten metal meshes in which the metal mesh 1 is arranged at odd positions and the metal mesh 11 is arranged at even positions and tapping one end face lightly on a plane is also used. A laminate can be obtained.

  Considering the application of the laminate as a gas filter, depending on the application, air permeability (if the air permeability is increased, the filterability decreases) and filterability (if the filterability is increased, the air permeability is increased). It is important to meet the conflicting requirement that

  As is apparent from FIG. 3, the wire diameter (diameter of the convex intersection) and the pitch are adjusted from the viewpoint of satisfying both air permeability and filterability.

  Next, another type of gas filter will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view of the wire mesh. The above-mentioned “(A2) metal wire has different wire diameters, different pitches between the convex intersections, and the spacing between the convex intersections of one of the metal meshes. It is a figure for demonstrating the lamination | stacking state of the two metal meshes which have the relationship "is larger than the diameter of the convex cross | intersection part of the other metal mesh."

The interval (w ₁ ) between the convex intersecting portions 4 of the wire mesh ₁ is set to be larger than the diameter (D ₃ ) of the convex intersecting portion 14 of the wire mesh 11, and further, P ₁ <P ₂ . .

When the metal mesh 1 and the metal mesh 11 are laminated, there may be a convex intersection 14 at the position of the metal wire 3 between the convex intersections 4, but even at that time, the metal wire 3 is partially convex. Since it is only covered by the intersection 14 (w ₁ > D ₃ ), it can be cut at the metal lines 3 and 13 (broken line positions in FIG. 4) of the portion not covered by the convex intersection 14. Further, as having a relationship of w _1> D _3, since the convex intersections 14 can slide between 4 two convex cross section, it is easy to superimpose the wire mesh 1,11.

  As needed, the laminated body may sandwich ceramic fiber, steel wool, glass wool or the like as an elastic filter material for each layer or every two or more layers.

  The laminate may be compression-molded into a desired shape such as a flat plate or cylinder, and from the viewpoint of facilitating transportation and storage, a part or all of the end face of the laminate is sandwiched and fixed. May be.

  The laminate is used as a gas filter, and is particularly suitable as a gas filter for use in an air bag gas generator.

(2) Second Embodiment A gas filter will be described with reference to FIGS. FIG. 5 is a schematic cross-sectional view of a wire mesh, and shows the state of lamination of two wire meshes having the relationship of “(B1) metal wires having different wire diameters and the same pitch between convex intersections”. It is a figure for demonstrating.

  As shown in FIG. 5, a wire mesh 21 is laminated on the wire mesh 1. The vertical and horizontal dimensions of the wire mesh 21 and the wire mesh 1 are the same.

  The diameter of the metal wire (lateral) 23 of the wire mesh 21 is larger than the diameter of the metal wire (lateral) 3 of the wire mesh 1, and the diameter of the convex intersection 24 is larger than the diameter of the convex intersection 4.

The diameter of the convex intersection 24 is smaller than the pitch P ₁ but larger than the interval (w ₁ ) between the adjacent convex intersections 4 (D ₃ in the first embodiment shown in FIG. 3 described above). > W ₁ is preferred). When the distance (w ₁ ) between the convex intersections 4 adjacent to the diameter of the convex intersections 24 has the above relationship, the convex intersections 24 fit between the two convex intersections 4. Therefore, it does not become difficult to slide.

The pitch P ₃ between the convex intersections 24 is the same as the pitch P ₁ between the convex intersections 4. Note that all of the _{P 3} and _{P 1} are each identical.

  When the wire mesh 21 is laminated on the wire mesh 1, the wire mesh 1 and the wire mesh 21 are slidable with each other because they have the relationship (B1). For this reason, the convex intersection 24 is not fitted between the two convex intersections 4 and does not move. Since the vertical and horizontal dimensions of the wire mesh 21 and the wire mesh 1 are the same, it is easy to align the ends.

  A method of stacking a required number of sheets in the order of the metal mesh 21 on the metal mesh 1, the metal mesh 1 on the metal mesh 21, and the metal mesh 21 on the metal mesh 1, or a plurality of sheets as in the first embodiment. By using the method of obtaining a laminated body at a time by using, it is possible to easily obtain a plate-like laminated body having end faces that are finally aligned.

  Next, another type of gas filter will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view of a wire mesh, and the above-mentioned “(B2) metal wire has a different wire diameter and the same pitch between the convex intersecting portions, and further, the convex intersecting portion of one of the wire meshes. It is a figure for demonstrating the lamination | stacking state of two metal meshes which have the relationship that the space | interval is larger than the diameter of the convex cross | intersection part of the other metal mesh.

The interval (w ₁ ) between the convex intersecting portions 4 of the wire mesh ₁ is set to be larger than the diameter (D ₄ ) of the convex intersecting portion 24 of the wire mesh 21, and further P ₁ = P ₃ . .

When the metal mesh 1 and the metal mesh 21 are laminated, there may be a convex intersection 24 at the position of the metal wire 3 between the convex intersections 4, but even at that time, the metal wire 3 is partially convex. Since it is only covered by the intersection 24 (w ₁ > D ₄ ), it can be cut at portions of the metal lines 3 and 23 (broken line positions in FIG. 6) that are not covered by the convex intersection 24. Further, if the relationship of w ₁ > D ₄ is satisfied, the convex intersection 24 can slide between the two convex intersections 4, so that it is easy to overlap the metal meshes 1, 21.

  As needed, the laminated body may sandwich ceramic fiber, steel wool, glass wool or the like as an elastic filter material for each layer or every two or more layers.

  The laminate may be compression-molded into a desired shape such as a flat plate or cylinder, and from the viewpoint of facilitating transportation and storage, a part or all of the end face of the laminate is sandwiched and fixed. May be.

  The laminate is used as a gas filter, and is particularly suitable as a gas filter for use in an air bag gas generator.

(3) Third Embodiment A gas filter will be described with reference to FIGS. FIG. 7 is a schematic cross-sectional view of a wire mesh, and illustrates the laminated state of the two wire meshes having the relationship of “(C1) the wire diameter of the metal wire is the same and the pitch between the convex intersections is different”. It is a figure for doing.

  As shown in FIG. 7, a wire mesh 31 is laminated on the wire mesh 1. The vertical and horizontal dimensions of the wire mesh 31 and the wire mesh 1 are the same.

  The diameter of the metal wire (lateral) 33 of the wire mesh 31 is the same as the diameter of the metal wire (lateral) 3 of the wire mesh 1, and the diameter of the convex intersection 34 is the same as the diameter of the convex intersection 4.

The pitch P ₄ between the convex intersections 34 is larger than the pitch P ₁ between the convex intersections 4. All P ₄ and P ₁ are the same.

  7 and FIG. 2B are the same except that the pitch between the convex intersections of the wire mesh 31 and the wire mesh 1b is different, but in FIG. 7, the wire mesh 1 and the wire mesh 31 slide in the length direction. In FIG. 2B, the wire meshes 1a and 1b are not slidable. This is because, in FIG. 7, the number of convex intersections 34 of the metal mesh 31 is small (five in the figure), and in FIG. 2B, the number of convex intersections 4 of the metal mesh 1b is large (10 in the figure). The contact points between the wire mesh 1 and the wire mesh 31 are significantly less than the contact points between the wire meshes 1a and 1b, and the convex intersections of other wire meshes fitted between the convex intersections of one wire mesh. This is because the number is overwhelmingly small.

  When the wire mesh 31 is laminated on the wire mesh 1, the wire mesh 1 and the wire mesh 31 are slidable with each other because they have the relationship (C1). For this reason, the convex intersection 34 does not get stuck between the two convex intersections 4 and does not move. And since the vertical and horizontal dimensions of the wire mesh 31 and the wire mesh 1 are the same, it becomes easy to align the ends.

  In this way, a method of laminating a required number of sheets in the order of the wire mesh 31 on the wire mesh 1, the wire mesh 1 on the wire mesh 31, and the wire mesh 31 on the wire mesh 1, or a plurality of sheets as in the first embodiment. By using the method of obtaining a laminated body at a time by using it, it is possible to easily obtain a plate-like laminated body having end faces that are finally aligned.

  Next, another type of gas filter will be described with reference to FIG. FIG. 8 is a schematic cross-sectional view of a wire mesh. The above-described “(C2) metal wire has the same wire diameter, a different pitch between the convex intersections, and further, the convex intersection of one of the metal meshes. It is a figure for demonstrating the lamination | stacking state of the two metal meshes which have the relationship that the space | interval is smaller than the diameter of the convex cross | intersection part of the other metal mesh.

The interval (w ₁ ) between the convex intersecting portions 4 of the wire mesh ₁ is set to be smaller than the diameter (D ₅ ) of the convex intersecting portion 34 of the wire mesh 31, and further, P ₁ <P ₄ is satisfied. .

When the metal mesh 1 and the metal mesh 31 are laminated, the interval (w ₁ ) between the convex intersections 4 is set to be smaller than the diameter (D ₅ ) of the convex intersections 34 (w _{1 <D} 5). For this reason, since the convex intersection 34 is not fitted between the convex intersections 4, it is easy to superimpose the metal meshes 1, 31.

  As needed, the laminated body may sandwich ceramic fiber, steel wool, glass wool or the like as an elastic filter material for each layer or every two or more layers.

  The laminate may be compression-molded into a desired shape such as a flat plate or cylinder, and from the viewpoint of facilitating transportation and storage, a part or all of the end face of the laminate is sandwiched and fixed. May be.

  The laminate is used as a gas filter, and is particularly suitable as a gas filter for use in an air bag gas generator.

  In the above first to third embodiments, the mode in which a plain weave wire mesh is used has been described. In particular, in the case of plain woven, twill woven, and twilled wire meshes, the wire materials of the two wire meshes to be overlapped are suitable for the orientations shown in FIGS. Also, different woven wire meshes may be combined and laminated, for example, a combination of plain woven wire mesh and twill woven wire mesh, or a combination of plain woven wire mesh and twill woven wire mesh.

(4) Fourth Embodiment A gas filter will be described with reference to FIG. FIG. 9 is a cross-sectional view of an elastic filter medium layer between metal meshes constituting a laminate.

  Elastic filter media 41, 42, 43 are sandwiched between the plurality of wire meshes 1. As the elastic filter media 41, 42 and 43, those selected from ceramic fibers, steel wool and glass wool are used alone or in combination.

  The wire mesh used in this form may be combined so as to satisfy the relationship (A1), (B1), (C1) or (A2), (B2), (C2), or the same wire mesh is laminated. May be. Expanded metal can be used instead of the wire mesh.

  By combining a wire mesh and an elastic filter material, problems such as those shown in FIGS. 2A and 2B do not occur in the wire mesh laminating operation. The filtration performance according to a use can be provided.

  The laminate may be compression-molded into a desired shape such as a flat plate or cylinder, and from the viewpoint of facilitating transportation and storage, a part or all of the end face of the laminate is sandwiched and fixed. May be.

(5) Fifth Embodiment The gas filter obtained in the first to fourth embodiments is formed into a cylindrical filter 50 as shown in FIG. Can be used as a filter. Examples of the gas generator for an air bag include the gas generator shown in FIG. 1 of JP-A-10-181516, FIG. 1 of JP-A-2001-97175, and FIG. 1 of WO00 / 48868. .

  The cylindrical filter of FIG. 10 has the end face 51 aligned (there is no unevenness as shown in FIG. 2B), and therefore, when arranged in the gas discharge path in the gas generator, the wall surface forming the gas discharge path It can be fitted snugly without any gaps. For this reason, the high-temperature gas generated by the combustion of the gas generating agent does not cause a short pass and reliably passes through the cylindrical filter, so that the combustion residue is filtered, the gas temperature is lowered, and the airbag is normally expanded. Is done.

(A) is a top view of the wire mesh used for the filter for gas, (b) is sectional drawing of a wire mesh. (A), (b) is explanatory drawing of the lamination | stacking method (prior art) of the wire net when manufacturing the filter for gas. Explanatory drawing of the lamination | stacking method (this invention) of the wire mesh when manufacturing the filter for gas. Explanatory drawing of the lamination | stacking method (this invention) of the wire mesh when manufacturing the filter for gas which is other embodiment. Explanatory drawing of the lamination | stacking method (this invention) of the wire mesh when manufacturing the filter for gas which is other embodiment. Explanatory drawing of the lamination | stacking method (this invention) of the wire mesh when manufacturing the filter for gas which is other embodiment. Explanatory drawing of the lamination | stacking method (this invention) of the wire mesh when manufacturing the filter for gas which is other embodiment. Explanatory drawing of the lamination | stacking method (this invention) of the wire mesh when manufacturing the filter for gas which is other embodiment. Explanatory drawing of the lamination | stacking method (this invention) of the wire mesh when manufacturing the filter for gas which is other embodiment. The perspective view of the cylindrical filter used for the gas generator for airbags.

Explanation of symbols

1, 11, 21, 31 Wire mesh 2 Metal wire (vertical)
3, 13, 23, 33 Metal wire (horizontal)
4, 14, 24, 34 Convex intersection

Claims (5)

A gas filter comprising a laminate in which a plurality of wire meshes are laminated and deformed as necessary,
The wire mesh constituting the laminate has a plurality of convex intersections formed by intersecting a plurality of metal wires,
Adjacent wire meshes are slidable by having any one of the following relationships (A1), (B1), and (C1), and the plurality of wire meshes are uneven on the outer peripheral surface of the laminate. Gas filters that are combined so that they do not occur.
(A1) The wire diameters of the metal wires are different and the pitch between the convex intersections is different;
(B1) The wire diameters of the metal wires are different and the pitch between the convex intersections is the same;
(C1) the wire diameter of the metal wire is the same, and the pitch between the convex intersections is different; The gas filter according to claim 1, wherein adjacent metal meshes have one of the following relationships (A2), (B2), and (C2).
(A2) The wire diameters of the metal wires are different, the pitches between the convex intersections are different, and the distance between the convex intersections of one metal mesh is larger than the diameter of the convex intersection of the other metal mesh. Be a thing;
(B2) The wire diameters of the metal wires are different and the pitch between the convex crossing portions is the same, and the interval between the convex crossing portions of one wire mesh is larger than the diameter of the convex crossing portion of the other wire mesh. Is also large;
(C2) The wire diameter of the metal wire is the same, the pitch between the convex intersections is different, and the interval between the convex intersections of one metal mesh is larger than the diameter of the convex intersection of the other metal mesh. Be small;   The gas filter according to claim 1 or 2, further comprising an elastic filter medium layer between the metal meshes constituting the laminate.   The gas filter according to any one of claims 1 to 3, wherein a part or all of the end face of the laminate is fixed by being sandwiched by a sandwiching tool. The gas filter according to any one of claims 1 to 4, which is for a gas generator used for an air bag.

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