JP2013035385A - Filter for airbag inflator and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter for an airbag inflator excellent in filter strength and filter property, and a method for manufacturing the same.SOLUTION: In the method for manufacturing the filter for an airbag inflator including steps of preparing a mat wire mesh, rolling the mat wire mesh, and winding the mat wire mesh after being rolled into a cylindrical shape, the step of winding the mat wire mesh after rolling into a cylindrical shape includes a first step of fixing the mat wire meshes overlapping each other in winding once or twice, a second step of further winding the mat wire mesh once or twice or more after fixing, and a third step of fixing the outermost mat wire mesh after being further wound once or twice or more and a mat wire mesh adjacent to the outermost mat wire mesh to each other.

Description

  The present invention relates to a filter for an airbag inflator and a method for manufacturing the same. More specifically, the present invention relates to an inflator filter for an air bag device that reduces the impact received by a passenger during a car collision accident, thereby improving the safety of the passenger, and a method for manufacturing the same.

  Airbags have been put into practical use as protecting passengers from secondary collisions during automobile collisions. This air bag quickly detects a collision of an automobile, determines the extent of the collision, sends an activation signal, an inflator (gas generator) that generates gas by the activation signal sent from the sensor, and the inflator And a bag that is expanded (inflated) by the gas flowing in from and protects the occupant.

  Inflators are roughly classified into three types: high-pressure gas inflators, solid propellant inflators, and hybrid inflators, depending on the gas generation method. Among them, a solid propellant inflator 30 mainly used for an airbag for a driver's seat includes an igniter (ignition device) 33 ignited by an operation signal from the above-described sensor and an igniter 33 as shown in FIG. A gas generating agent 34 that explosively burns to generate gas, a storage portion 35 thereof, an air bag inflator filter 10 that filters a gas having a solid residue at a high temperature generated by explosive combustion of the gas generating agent 34, and air In general, a diffuser 32 and the like for allowing the gas that has passed through the bag inflator filter 10 to flow into the bag are provided. Reference numeral 31 denotes a disc-shaped case that houses the above-described filter, and reference numeral 36 denotes a passage hole through which the gas passes.

  Further, if the deployment speed of the airbag is too fast, the occupant is damaged, and if the deployment speed is too slow, the occupant cannot be protected. Therefore, the inflator is required to deploy the airbag at an appropriate speed according to the size and structure of the equipped vehicle. This deployment speed can be adjusted by the type of gas generating agent, the amount of gas generated, and the characteristics of the filter for the airbag inflator.

  In Patent Document 1, a single wire rod (also referred to as a flat wire) having a thickness of 0.20 mm to 0.40 mm and a width of 0.50 mm to 1.0 mm is used. The jig is locked at an appropriate position, the wire is wound around the jig and knitted to form a cylindrical body, and then the other end of the knitted wire is joined to the appropriate position of the cylindrical body, and the jig is removed from the cylindrical body. Thus, a hollow cylindrical body is obtained. A technique for manufacturing a filter for an air bag inflator by sintering the hollow cylindrical body in a temperature range of 1000 ° C. to 1500 ° C. in a nitrogen gas atmosphere has been proposed. This technique has a simple structure but high rigidity and does not increase the manufacturing cost. Furthermore, it is said that an air bag inflator filter having various different characteristics can be easily manufactured by variously changing the wire type, the number of windings, the winding angle, the pitch, and the sintering conditions.

  Patent Document 2 proposes a metal filter manufacturing technique. According to this technology, the fabric roll of the tatami woven wire mesh is rolled out while being unwound, and the heat treatment is performed to combine the lower portion while unwinding the fabric roll of the woven woven wire mesh that has been rolled down. It is characterized by winding. According to this technique, it is said that a metal filter having good mechanical strength can be obtained by using stainless steel as the wire of the tatami woven wire mesh and the fine mesh structure of the tatami woven wire mesh.

JP 2007-302237 A JP-A-7-136428

  The air bag inflator filter proposed in Patent Document 1 is said to have high rigidity, but in that technology, the flat wire is wound and knitted as it is, and then sintered into a cylindrical body. It is not possible to fully meet the demand for further improvement.

  Further, in the technique proposed in Patent Document 1, since the mesh of the filter is refined by winding and knitting a metal wire, the mesh is further refined to produce a filter for an airbag inflator having excellent filter characteristics. There are difficulties. In addition, even if possible, there is a difficulty that its manufacture is difficult.

  The technique proposed in Patent Document 2 is a filter having a single layer structure of a tatami woven wire mesh, and has a drawback that the filter strength is not sufficient for use in an airbag inflator. In addition, according to this technology, since it has a step of sintering the wire rods after rolling down the wire mesh, the processing strength improved during rolling may be reduced by the heat treatment, and as an airbag inflator application There is a drawback that the filter strength is not sufficient for use.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an air bag inflator filter excellent in filter strength and filter characteristics and a method for producing the same.

  In order to solve the above problems, a method for manufacturing a filter for an airbag inflator according to the present invention includes a step of preparing a tatami woven wire mesh, a step of rolling the tatami woven wire mesh, and a cylinder of the tatami woven wire mesh after rolling. A step of winding the tatami woven wire mesh after rolling into a cylindrical shape, and fixing the tatami woven wire mesh that overlaps when wound once or twice, and after fixing A second step of further winding the tatami woven wire mesh once or twice or more, a tatami woven wire mesh adjacent to the outermost tatami woven wire mesh after being wound once or twice or more; And a third step of fixing.

  According to the present invention, the air bag inflator filter is manufactured by rolling the tatami woven wire mesh and fixing it after winding, so that the manufactured air bag inflator filter is a tatami weave having a complicated three-dimensional mesh structure. The wire mesh is rolled. The rolled tatami woven wire mesh increases the shape retention strength of the three-dimensional structure. In the present invention, the filter is formed by winding a tatami woven wire mesh with increased shape retention strength a plurality of times, so that the manufactured filter for an airbag inflator has improved filter strength. Moreover, in this invention, since a mesh is refined | miniaturized by rolling a tatami woven wire mesh, the manufactured filter for airbag inflators becomes the thing excellent in the filter characteristic.

  In the method for manufacturing a filter for an airbag inflator according to the present invention, the fixing means performed in the first step and the third step is configured to be welding.

  According to this invention, since the fixing means described above is welded, the tatami woven wire meshes can be fixed with high strength, and a filter for an airbag inflator having excellent filter strength can be manufactured.

  In the manufacturing method of the filter for airbag inflators which concerns on this invention, it is preferable that the rolling rate in the process of rolling the said tatami-woven wire mesh is 10%-60%.

  According to this invention, since the rolling rate in the step of rolling the tatami woven wire mesh is 10% to 60%, the produced filter for airbag inflator has increased the shape retention strength of the three-dimensional structure of the tatami woven wire mesh. , Can provide higher filter strength. Moreover, the filter characteristics can be further improved by making the mesh finer.

  An air bag inflator filter according to the present invention for solving the above-mentioned problem is a hollow cylindrical body formed by rolling a tatami-woven wire mesh rolled a plurality of times with a flat surface of the mesh, the hollow cylindrical body An innermost tatami woven wire mesh and a tatami woven wire mesh adjacent to the tatami woven wire mesh are fixed, and an outermost tatami woven wire mesh of the hollow cylindrical body and a tatami woven wire mesh adjacent to the tatami woven wire mesh. And are fixed.

  According to the present invention, the surface of the tatami woven wire mesh constituting the airbag inflator filter is flat and deformed, so that the mesh of the woven woven wire mesh has a complicated and refined three-dimensional structure. As a result, a hollow cylindrical body in which such a tatami woven wire mesh is wound a plurality of times becomes an air bag inflator filter having excellent filter characteristics. Moreover, since the surface of the tatami woven wire mesh constituting the air bag inflator filter is deformed flat by rolling, the shape retention strength of the three-dimensional structure of the tatami woven wire mesh is increased. As a result, the tatami woven wire mesh is wound a plurality of times, and the innermost and outermost woven wire meshes are fixed, so that the filter strength is excellent.

  In the airbag inflator filter according to the present invention, adjacent tatami woven wire meshes are fixed by welding.

  According to this invention, since adjacent tatami woven wire meshes are fixed by welding, the tatami woven wire meshes are fixed with high strength, and the filter strength is excellent.

In the airbag inflator filter according to the present invention, a pressure loss is 0.1 kPa to 100 kPa when air of 1 m ³ is passed per minute from the innermost circumferential side to the outermost circumferential side of the hollow cylindrical body.

According to this invention, the pressure loss is 0.1 kPa to 100 kPa when air of 1 m ³ is passed per minute in the direction from the innermost periphery to the outermost periphery of the hollow cylindrical body, so that the filter characteristics are excellent.

  According to the method for manufacturing a filter for an airbag inflator according to the present invention, a tatami woven wire mesh having a complicated three-dimensional structure of a mesh is rolled, and the rolled tatami woven wire mesh is a shape-retaining shape of a three-dimensional structure. Strength is increasing. As a result, the manufactured airbag inflator filter is formed by winding the tatami woven wire mesh having increased shape retention strength a plurality of times, so that the filter strength is improved. In addition, the manufactured filter for an airbag inflator has excellent filter characteristics because the mesh is refined by rolling the woven woven wire mesh.

  According to such a manufacturing method according to the present invention, a filter for an airbag inflator having desired characteristics (filter strength, filter characteristics) can be manufactured with less tatami woven wire mesh, so that the airbag is thin, lightweight, and small. Inflator filters can be manufactured. Moreover, the filter for airbag inflators which has the target characteristic can be manufactured easily by changing suitably the mesh | mesh of a woven wire mesh, the wire diameter of a wire, the kind of wire, and a rolling rate. The mesh represents the number of vertical lines and the number of horizontal lines per inch.

  According to the airbag inflator filter of the present invention, since the mesh has a complicated and refined three-dimensional structure, a hollow cylindrical body in which such a tatami wire mesh is wound a plurality of times has excellent filter characteristics. This is a filter for airbag inflators. Moreover, since the surface of the tatami woven wire mesh constituting the air bag inflator filter is deformed flat by rolling, the shape retention strength of the three-dimensional structure of the tatami woven wire mesh is increased. As a result, the tatami woven wire mesh is wound a plurality of times, and the innermost and outermost woven wire meshes are respectively fixed to the adjacent tatami woven wire mesh, so that the filter strength is excellent.

It is a perspective view which shows an example of the filter for airbag inflators which concerns on this invention. It is a flowchart of the manufacturing process of the filter for airbag inflators which concerns on this invention. (A) is a top view of a plain woven wire mesh, (B) is a top view of a twill woven wire mesh. It is a perspective view of a flat woven wire mesh. (A) is a plane view photograph of the plain woven wire mesh before rolling, and (B) is a plane view photograph of the plain woven wire mesh after rolling. (A) is sectional drawing of the plain woven wire mesh before rolling, (B) is sectional drawing of the flat woven wire mesh after rolling. It is a winding process figure of the filter for airbag inflators. It is a perspective view which shows another example of the filter for airbag inflators which concerns on this invention. It is a section perspective view showing an example of a solid propellant type inflator used for a driver's seat air bag.

  Hereinafter, a filter for an airbag inflator and a manufacturing method thereof according to the present invention will be described with reference to the drawings. The technical scope of the present invention is not limited only to the following description and drawings.

  For example, as shown in FIG. 9, the airbag inflator filter 10 ignites the gas generating agent 34 by a signal from the sensor via the igniter 33, and removes the high-temperature solid residue generated by the explosive combustion of the gas generating agent 34. It performs the function of filtering the gas it has and sometimes cooling it at the same time. The exterior shape of the airbag inflator filter 10 is a hollow cylindrical body, and a front airbag installed on the steering wheel of the driver's seat and the dashboard of the passenger seat, or a side airbag installed on the door of the driver's seat or the passenger seat. Equipped with an inflator 30 that can be incorporated into

[Method for producing filter for airbag inflator]
The manufacturing method of the airbag inflator filter 10 is a method of manufacturing the airbag inflator filter 10 shown in FIG. As shown in FIG. 2, the manufacturing method includes a step of preparing the tatami woven wire mesh 1, a step of rolling the tatami woven wire mesh 1, and a winding step of the tatami woven wire mesh 1 after rolling. Each step will be described in more detail.

(Preparation process)
The preparation step is a step of preparing the tatami woven wire mesh 1. The preparation of the tatami woven wire mesh 1 may be a commercially available one, or may be manufactured by oneself. When manufacturing the tatami woven wire mesh 1 by itself, the manufacturing method of the general tatami woven wire mesh 1 can be applied.

  The tatami woven wire mesh 1 is included in the woven wire mesh together with the plain woven wire mesh and the twilled wire mesh. In the present invention, the woven wire mesh 1 is used among the woven wire meshes. As shown in FIG. 3, the tatami woven wire mesh 1 includes a flat woven wire mesh 1A and a twill woven wire mesh 1B. In the present invention, either tatami woven wire mesh may be used. The flat woven wire mesh 1A is a line in which vertical lines 12 'and horizontal lines 11' intersect each other, and the horizontal lines 11 'are in contact (adjacent horizontal lines are in contact with each other). This refers to a wire mesh with weaving like a tatami mat (JIS G 3555DW). Further, the twilled woven wire mesh 1B refers to a line in which the horizontal lines 11 'are arranged adjacent to each other, and two or more vertical lines 12' and two horizontal lines 11 'are crossed over each other. Such a tatami woven wire mesh 1 has a three-dimensional structure in which the mesh is more complex than other wire meshes such as plain woven wire mesh and twill woven wire mesh, so that the wires reinforce each other and have high strength. Therefore, the tatami woven wire mesh 1 has little positional deviation of the wire and has excellent shape retention strength.

  When viewed in plan as shown in FIG. 3, the tatami-woven wire mesh 1 cannot confirm the opening between the wires, but when viewed as shown in FIG. 4, the opening 7 between the wires. Can be confirmed. Accordingly, when the gas passes through the tatami woven wire mesh 1, it always collides with the wire. Therefore, the airbag inflator filter 10 manufactured using the tatami woven wire mesh 1 has excellent filter characteristics. . The filter characteristics are the performance of the filter to capture the solid residue contained in the gas when the gas passes through the filter.

  The plain woven wire mesh and the twill woven wire mesh other than the tatami woven wire mesh can confirm an opening between the wires when viewed in plan. For this reason, it is difficult to make the mesh openings finer even if rolled as in the rolling process described later. On the other hand, when the tatami woven wire mesh 1 is viewed in plan as shown in FIG. 3, the opening between the wires cannot be confirmed, but when viewed as shown in FIG. It has a structure that the opening 7 can be confirmed between them. Therefore, since the opening 7 is in the vertically downward direction of the wire rod, the mesh opening 7 can be easily made fine when rolled in a rolling process described later. Furthermore, the airbag inflator filter 10 which has the target characteristic can be easily manufactured by employ | adopting arbitrarily various tatami woven wire nets from which a mesh, the wire diameter of a wire, and the kind of wire differ.

  Although it does not specifically limit as a kind of wire used for the tatami-woven wire mesh 10, Preferably, iron, cast iron, stainless steel, a nickel alloy, a titanium alloy, a copper alloy etc. can be mentioned. More preferably, austenitic stainless steel (SUS304) or mild steel (SWRM) can be used. Examples of the cross-sectional shape of the wire include a perfect circle, an ellipse, a rectangle, and a square, and a perfect circle is preferably used.

  The wire diameter of the wire can be changed as appropriate according to the intended characteristics. When the cross-sectional shape of the wire is a perfect circle, it is preferably in the range of 0.01 mm to 2 mm, more preferably in the range of 0.1 mm to 1 mm. When the wire diameter exceeds 2 mm, the opening 7 of the mesh of the woven woven wire mesh becomes too large, and sufficient filter characteristics may not be obtained. If the wire diameter is less than 0.01 mm, the mesh opening 7 of the woven woven wire mesh 10 becomes too fine, and the high-pressure gas generated by the combustion of the gas generating agent is difficult to pass. As a result, the airbag inflator filter 10 may not be able to withstand the gas pressure.

(Rolling process)
A rolling process is a process of rolling the prepared tatami wire mesh 1. By this rolling process, the shape retention strength of the three-dimensional structure of the tatami woven wire mesh 1 is increased, and the filter strength can be further improved. Moreover, the filter characteristics can be further improved by making the mesh finer. As shown in FIG. 5 and FIG. 6, the wire of the tatami woven wire mesh 1 is plastically deformed into a horizontal line 11 having a flat cross-sectional shape by rolling, and the vertical line 12 ′ has a flat cross-sectional shape. Plastic deformation occurs in the vertical line 12. The flat wire acts to increase the shape retention strength of the three-dimensional structure of the tatami woven wire mesh 1. The tatami woven wire mesh 1 with increased shape retention strength can be improved in filter strength after being wound a plurality of times in the winding process described below to form the airbag inflator filter 10.

  Moreover, as shown in FIG. 6, the surface wire is deformed flat by rolling, and the mesh of the tatami-woven wire mesh 1 is refined. As a result, the airbag inflator filter 10 manufactured using the rolled woven wire mesh 1 is excellent in filter characteristics.

  By using the tatami woven wire mesh whose shape retention strength and filter strength are improved by rolling, the air bag inflator filter 10 having the desired characteristics (filter strength and filter properties) can be manufactured with less tatami woven wire mesh 1. As a result, a thin, lightweight and small airbag inflator filter 10 can be manufactured.

  As the rolling means, a general rolling processing means for obtaining a predetermined cross-sectional shape while passing the tatami-woven wire mesh 1 between two rotating cylindrical rolls and reducing the cross-sectional thickness thereof can be employed. The rolling may be cold rolling or hot rolling. Further, two-stage rolling using two rolls, four-stage rolling using four rolls, or six-stage rolling using six rolls may be used. Moreover, the Zenzimer rolling which arrange | positioned 19 rolls, a planetary rolling, and a universal rolling may be sufficient.

The degree of rolling is determined by the rolling rate. The rolling rate (r) is the sheet thickness reduction rate of the material to be rolled (tatami woven wire mesh 1), and is defined by r (%) = (h ₂ −h ₁ ) / h ₁ × 100. Here, as shown in FIG. 6, h ₁ is the thickness of the wire mesh 1 woven mat before rolling (mm), h ₂ is a tatami woven thickness of wire mesh 1 after rolling (mm).

  The rolling rate in the step of rolling the tatami woven wire mesh 1 is preferably 10% to 60%. The tatami woven wire mesh 1 rolled at a rolling rate in this range is improved in shape retention strength of a three-dimensional structure and excellent in filter strength. When the rolling rate is less than 10%, the shape retention strength of the three-dimensional structure of the tatami woven wire mesh 1 may not be sufficiently improved. On the other hand, when the rolling rate exceeds 60%, the opening 7 of the mesh of the woven woven wire mesh 1 becomes too fine, and the high-pressure gas generated by the combustion of the gas generating agent becomes difficult to pass. As a result, the airbag inflator filter 10 may not be able to withstand the gas pressure. A more preferable range of the rolling rate is 30% to 60%. The tatami wire mesh 1 rolled at a rolling rate in this range has a three-dimensional structure with improved shape retention strength and excellent filter characteristics.

  It is desirable not to have a heating process such as sintering after the rolling process. By not having a heating step, it is possible to maintain the shape retention strength and filter characteristics of the woven woven wire mesh 1 after rolling. On the other hand, when the tatami woven wire mesh 1 after being heated is heated, the shape retention strength of the three-dimensional structure of the tatami woven wire mesh 1 may decrease.

(Winding process)
The winding step is a step of winding the tatami woven wire mesh 1 after rolling. As shown in FIG. 7, the tatami woven wire mesh 1 after rolling is wound around a cylindrical rotary winding jig 20 a plurality of times. This is a step of forming a hollow cylindrical body of the airbag inflator filter 10. The airbag inflator filter 10 formed by this winding process has excellent filter strength and filter characteristics.

  The winding step includes a first step of fixing the overlapping tatami woven wire meshes 1 when the rolled tatami woven wire mesh 1 is wound once or twice in a cylindrical shape, and the tatami woven wire mesh 1 described above after fixing. A second step of winding the wire once or twice or more, and a tatami woven wire mesh 1 adjacent to the outermost tatami wire mesh 1 after being wound once or twice or more. It has three steps with a third step of fixing. The three steps will be described in detail.

  As shown in FIG. 7A, the first step is a step of fixing the tatami woven wire meshes 1 that overlap when the tatami woven wire meshes 1 are wound once or twice in a cylindrical shape. In this step, first, the winding start end 2 of the tatami woven wire mesh 1 is locked to the cylindrical rotary winding jig 20. Next, the tatami wire mesh 1 is wound once or twice under a constant tension while rotating the rotary winding jig 20 in a certain direction. In the example of FIG. 7A, a shape wound once is shown. Thereafter, the tatami woven wire meshes 1 are fixed to each other at the overlapping portion. Reference numeral 3 indicates a fixed portion. By fixing at the overlapping portion, the hollow end can be made a hollow cylindrical body without the end 2 being separated. By this series of steps, the hollow cylindrical body can be configured without the wound tatami wire meshes 1 being separated. In addition, when it winds twice, the tatami woven wire nets 1 of the part which the tatami woven wire meshes 1 overlapped and became 3 layers are fixed.

  As shown in FIG. 7B, the second step is a step of further winding the tatami woven wire mesh 1 fixed in the first step once or twice or more. In this step, the rotary winding jig 20 is further axially rotated in a certain direction, and the tatami woven wire mesh 1 is further wound once or twice under a constant tension. The number of windings at this time is arbitrarily selected depending on the shape retention strength and filter characteristics of the tatami woven wire mesh 1. Usually, it is 1 time or multiple times of 2 to 20 times. After winding a predetermined number of times, the shaft rotation of the rotary winding jig 20 is stopped. By this series of steps, the manufactured airbag inflator filter 10 is superior in filter strength as compared with a single-layer filter.

  In the third step, as shown in FIG. 7C, the outermost tatami wire mesh 1 after being wound a plurality of times in the first step and the second step, and the tatami mat adjacent to the outermost tatami wire mesh 1 This is a step of fixing the woven wire mesh 1. In this step, at least the outermost tatami woven wire mesh 1 and the inner tatami woven wire mesh 1 adjacent thereto may be fixed, and may be fixed together with the inner tatami woven wire mesh 1. The fixed portion in this step is preferably directly above the fixed portion in the first step. By fixing directly above the fixing portion in the first step, the region where the filter characteristics are uniform can be maximized. Depending on the fixing means, the fixing portion may be deformed or the strength may be reduced. In this case, the fixing method is preferably performed before or after the axial direction of the fixing portion in the first step. Such fixation can minimize the reduction in the area where the filter characteristics are uniform. After fixing, the tatami-woven wire mesh 1 may be cut near the fixing portion. Reference numeral 4 denotes an end portion after cutting. By this step, the shape of the hollow cylindrical body of the airbag inflator filter 10 can be maintained without breaking the wound tatami wire mesh 1.

  Fixing is performed in the first step and the third step described above. As the fixing means, a brazing-type fixing means using an adhesive or a brazing agent, a pressure-welding type fixing means by caulking, etc., a fusion-welding type fixing means for partially melting and fixing the tatami-woven metal mesh 1 itself, and a tatami-woven metal mesh 1 And resistance welding type fixing means for fixing the joint under pressure by increasing the temperature of the joint. In the present invention, resistance welding type fixing means is preferably applied. The resistance welding type fixing means is a method in which an electric current is applied to a portion to be welded (tatami woven wire mesh 1), the temperature of the joint is increased by resistance heat generated by the electric current, and welding is performed under pressure. The resistance welding means can be broadly classified into lap resistance welding methods such as spot welding, projection welding, and seam welding, and butt welding methods such as abset welding, crash welding, and butt seam welding. Here, in terms of productivity, automation, cost, processing accuracy, and degree of deformation, lap resistance welding is preferable, and spot welding and seam welding are particularly preferably applied. These weldings can be controlled under conditions such as welding current, energization time, and applied pressure in consideration of the woven woven wire mesh 1. In the example of FIG. 7, the fixed portion of the tatami woven wire mesh 1 is sandwiched between the rotary winding jig 20 and a pressure electrode bar or bar (not shown), and the pressure electrode bar or bar is used as the rotary winding jig. In the state pressed in 20 directions, electricity is passed between the two and welding is performed.

  The airbag inflator filter 10 </ b> B shown in FIG. 8 is provided with a fixed portion 6 that fixes the outermost tatami wire mesh 1 and the tatami wire mesh 1 adjacent to the outermost tatami wire mesh 1. As shown in FIG. 9, the fixed portion 6 includes an air bag inflator filter 10 </ b> B in a disk-shaped case 31 in a solid propellant inflator 30 mainly used for a driver seat and a passenger seat air bag. It is preferable that it is provided in a portion facing the diffuser 32 when installed in the. The diffuser 32 is a portion where the high-pressure gas generated by the combustion of the gas generating agent 34 flows out into the bag, and the airbag inflator filter in the portion facing the diffuser 32 receives the gas pressure most strongly. Therefore, by providing the fixed portion 6 in the airbag inflator filter in the portion opposite to the diffuser 32, the strength of this portion can be improved and the airbag inflator filter 10B can be prevented from being damaged when the airbag is activated. it can. As a result, the airbag inflator filter 10B is more excellent in filter strength. Further, since the fixed portion 6 does not pass gas, it is possible to suppress the high-pressure gas generated by the combustion of the gas generating agent 34 from flowing out of the diffuser 32 abruptly. As a result, it is considered that the airbag inflator filter 10B can extend the time during which the gas is held in the inflator 30, and the filter characteristics and cooling function thereof are improved. Reference numeral 33 denotes an igniter, reference numeral 35 denotes a gas generating agent storage portion, and reference numeral 36 denotes a passage hole through which gas passes.

  The fixed portion 6 is provided so that the outermost periphery of the airbag inflator filter 10B rotates once in the circumferential direction. As the fixing means of the fixing portion 6, the various fixing means described above can be applied, but seam welding is preferable. Seam welding is a method in which an object to be welded (hollow cylindrical body) is processed with a rotating disk electrode and is sequentially welded while rotating, and has a feature that a nugget can be continuous. For seam welding to the airbag inflator filter 10B shown in FIG. 8, a rotary take-up jig 20 (see FIG. 7) is arranged on the inner side, and a rotary disk electrode (not shown) is arranged on the outer side. This is performed by applying pressure and current while rotating the disk electrode once in the circumferential direction of the outermost periphery of the airbag inflator filter 10B sandwiched between them.

(Cutting process)
As shown in FIG. 2, the cutting process can be introduced at any timing before or after the rolling process of the woven wire mesh 1 or after the winding process. By the cutting step, the hollow cylindrical body around which the tatami woven wire mesh 1 is wound can be processed into the size of the filter 10 for an air bag inflator as described later. When the cutting process is introduced before the rolling process, the prepared tatami woven wire mesh 1 is cut into an appropriate size, the cut tatami woven metal mesh 1 is rolled, and the rolled tatami woven metal mesh 1 is used for the winding process. Thus, the airbag inflator filter 10 is manufactured. Moreover, when the cutting process is introduced after the rolling process, the prepared tatami woven wire mesh 1 is rolled, the rolled tatami woven metal mesh 1 is cut into an appropriate size, and the cut tatami woven metal mesh 1 is subjected to a winding process. Thus, the airbag inflator filter 10 is manufactured. Moreover, when the cutting process is introduced after the winding process, the air bag inflator filter 10 having a target size is manufactured by cutting the hollow cylindrical body after the winding process into an appropriate size.

  According to the method for manufacturing a filter 10 for an airbag inflator according to the present invention, the tatami woven wire mesh 1 having a complicated three-dimensional structure of the mesh is rolled, and the rolled tatami woven wire mesh 1 has a three-dimensional structure. The shape retention strength of is increasing. As a result, the manufactured airbag inflator filter 10 is formed by winding the tatami woven wire mesh 1 with increased shape retention strength a plurality of times, and thus the filter strength is improved. In addition, the manufactured airbag inflator filter 10 has excellent filter characteristics because the mesh is refined by rolling the tatami-woven wire mesh 1.

  According to such a manufacturing method according to the present invention, the air bag inflator filter 10 having the desired characteristics (filter strength, filter characteristics) can be manufactured with less tatami wire mesh 1, so that it is thin, lightweight, and compact. The filter 10 for airbag inflators can be manufactured. Moreover, the airbag inflator filter 10 which has the target characteristic can be manufactured easily by changing suitably the mesh of the tatami-woven wire mesh 1, the wire diameter of a wire, the kind of wire, and a rolling rate.

[Airbag inflator filter]
As shown in FIGS. 1 and 8, the airbag inflator filter 10 is a hollow cylindrical body in which a tatami woven wire mesh 1 whose surface is deformed by rolling is wound a plurality of times. The air bag inflator filter 10 has a hollow cylindrical body in which the innermost tatami woven wire mesh 1 and a filter inner tatami woven wire mesh 1 adjacent to the tatami woven wire mesh 1 are fixed. The tatami woven wire mesh 1 at the outermost periphery of the body and the tatami woven wire mesh 1 inside the filter adjacent to the tatami woven wire mesh 1 are fixed.

  The surface of the tatami woven wire mesh 1 means both sides of the tatami woven wire mesh 1 in the thickness direction (that is, the outermost surfaces on both sides) in the cross-sectional view of the tatami woven wire mesh 1 shown in FIG. As shown in FIG. 6, 1 means that the cross-sectional shape of the wire 11 ′ is deformed and the surface in the thickness direction of the woven woven wire mesh 1 is a flat surface or a flat surface. The wire having such a surface has a flat form shown in FIG. 6 and a form that leaves other rolling traces. If the surface in the thickness direction of the tatami woven wire mesh 1 is flat, the inner surface of the tatami woven wire mesh 1 of the wire 11 ′ does not necessarily have to be flat.

  The cross-sectional shape of the wire 11 and 12 on the surface of the tatami woven wire mesh 1 is flattened by rolling in the tatami woven wire mesh 1 in which the cross section of the wire is a perfect circle, and the wire becomes a flat shape. The cross sections of the wire rods 11 and 12 on the inner side are kept in a perfect circle shape, and the wire rods are not so deformed. Therefore, a tatami woven wire mesh 1 using a wire having a perfect circular cross section, and by rolling the tatami woven wire mesh 1, the surface of the tatami woven wire mesh 1 is deformed flat, but its inner side The surface is a tatami woven wire mesh 1 that is not so flat and deformed, and a tatami woven wire mesh 1 that uses a wire with a flat cross section, and the surface of the tatami woven wire mesh 1 and its inner surface are flat. When compared with a certain woven wire mesh 1, it can be easily distinguished that the former is related to the present invention and the latter is not related to the present invention.

  In addition, about the fixing means of the tatami woven wire nets 1, since it is the same as that of the content demonstrated by the manufacturing method of the filter 10 for airbag inflators mentioned above, the description is abbreviate | omitted here. Moreover, since it is the same also to fix by welding, the description is abbreviate | omitted here.

  The size of the airbag inflator filter 10 can be appropriately determined according to the structure and size of the inflator 30 to be equipped. For example, if it is equipped with a disk-type inflator that can be incorporated into a front airbag, the inner diameter can be 5 mm to 80 mm, the outer diameter can be 30 mm to 90 mm, and the axial length can be 3 mm to 150 mm. If it is equipped with an inflator that can be incorporated in a side airbag, the inner diameter may be 3 mm to 40 mm, the outer diameter may be 5 mm to 50 mm, and the axial length may be 5 mm to 60 mm.

The filter characteristics can be evaluated by pressure loss. This pressure loss can be evaluated by the pressure loss when air of 1 m ³ per minute is passed from the innermost circumferential side to the outermost circumferential side of the airbag inflator filter 10. The pressure loss of the airbag inflator filter 10 is preferably 0.1 kPa to 100 kPa. When the pressure loss is less than 0.1 kPa, the solid residue contained in the high-pressure gas generated by the combustion of the gas generating agent easily passes through the mesh, and the filter characteristics are not sufficient. On the other hand, if the pressure loss exceeds 100 kPa, the airbag inflator filter 10 may not be able to withstand the gas pressure due to the difficulty of gas passage. A more preferable range of pressure loss is 2 kPa to 30 kPa. The airbag inflator filter 10 having a pressure loss in this range has a better balance between filter characteristics and filter strength.

  The method for measuring the pressure loss of the airbag inflator filter 10 is described in JP-A No. 11-20598, column 19, line 17 to column 20, line 43, FIGS. 8 and 9. First, a pipe (not shown) for sending air is attached to one end of the airbag inflator filter 10, and a support plate (not shown) is attached to the other end so as not to leak air. Next, the pressure can be measured by attaching a pressure gauge (not shown) to the support plate and flowing a certain amount of air from the inside of the air bag inflator filter 10.

  The pressure loss of the airbag inflator filter 10 is appropriately adjusted according to the characteristics of the airbag apparatus equipped with the airbag inflator filter 10. For example, when the solid residue contained in the high-pressure gas generated by the combustion of the gas generating agent is allowed to pass into the airbag, the pressure loss may be small or generated by the combustion of the gas generating agent. When the gas pressure is not large, the pressure loss may be large.

  As described above, the airbag inflator filter 10 according to the present invention has a hollow cylindrical filter structure in which a tatami woven wire mesh 1 whose surface is deformed flat is wound a plurality of times, so that the mesh is complicated and refined. Presents. As a result, the hollow cylindrical body in which the tatami woven wire mesh 1 is wound a plurality of times becomes an air bag inflator filter 10 having excellent filter characteristics. Further, since the surface of the tatami woven wire mesh 1 constituting the airbag inflator filter 10 is flattened by rolling, the shape retention strength of the three-dimensional structure of the tatami woven wire mesh 1 is increased. As a result, the tatami woven wire mesh 1 is wound a plurality of times, and the innermost and outermost woven wire meshes 1 are fixed, so that the filter strength is excellent.

  The present invention will be described in more detail with reference to experimental examples. The present invention is not limited to the following examples.

[Experimental Example 1]
The airbag inflator filter 10 was manufactured according to the following procedure. First, a thickness of 1.2 mm, 12/64 formed of a wire rod made of austenitic stainless steel (SUS304) having a cross-section with a wire diameter of 0.58 mm as the vertical wire 12 ′ and a wire diameter of 0.43 mm as the horizontal wire 11 ′. A mesh plain woven wire mesh 1A was prepared. Here, the mesh represents the number of vertical lines 12 ′ per inch / the number of horizontal lines 11 ′. Next, the prepared plain woven wire mesh 1A was rolled. Rolling was performed at a rolling rate of 30%. The thickness of the flat woven wire mesh 1A after rolling was 0.84 mm.

  Next, one end of the plain woven wire mesh 1A was fixed to the rotary winding jig 20 so that the X direction shown in FIG. After this flat woven wire mesh 1A was wound once, the overlapping flat woven wire mesh 1A was fixed at a pitch of 5 mm by spot welding using a pressure electrode rod. Further, after winding the flat woven wire mesh 1A three times in total, as shown in FIG. 1, the outermost flat woven wire mesh 1A was fixed by spot welding at a pitch of 5 mm using a pressure electrode rod. The flat woven wire mesh 1A after spot welding was cut to produce a hollow cylindrical air bag inflator filter 10. The length of the flat woven wire mesh 1A used was 350 mm, and the produced air bag inflator filter 10 had an inner diameter of 43.7 mm, an outer diameter of 48.2 mm, and a mass of 30 g.

  The wire on the surface of the flat woven wire mesh 1A constituting the airbag inflator filter 10 obtained in Experimental Example 1 was deformed flat, but the wire on the inner side of the flat woven wire mesh 1A was deformed too much. There wasn't.

[Experimental Examples 2 to 5]
In Experimental Examples 2 to 5, an airbag inflator filter 10 was produced in the same manner as in Experimental Example 1 except that the rolling rate was as shown in Table 1.

[Experimental Example 6]
In Experimental Example 6, first, a thickness of 0.24 mm as the vertical line 12 ′ and austenitic stainless steel (SUS304) having a wire diameter of 0.36 mm as the horizontal line 11 ′ and a cross-section of a wire having a true diameter of 0. A 72 mm, 24/110 mesh plain woven wire mesh 1A was prepared. Next, the prepared plain woven wire mesh 1A was rolled. Rolling was performed at a rolling rate of 10%. The thickness of the flat woven wire mesh 1A after rolling was 0.65 mm.
Subsequent winding steps were carried out in the same manner as in Experimental Example 1 to manufacture the airbag inflator filter 10. The length of the flat woven wire mesh 1A used was 503 mm, and the manufactured air bag inflator filter 10 had an inner diameter of 43.7 mm, an outer diameter of 47.5 mm, and a mass of 30 g.

[Experimental Examples 7 to 10]
In Experimental Examples 7 to 10, an airbag inflator filter 10 was produced in the same manner as in Experimental Example 6 except that the rolling rate was as shown in Table 1.

[Experimental Example 11]
In Experimental Example 11, the same plain woven wire mesh 1A as in Experimental Example 7 was prepared, and the prepared flat woven wire mesh 1A was rolled in the same manner as in Experimental Example 7. Next, one end of the plain woven wire mesh 1A was fixed to the rotary winding jig 20 so that the X direction shown in FIG. After this flat woven wire mesh 1A was wound once, the overlapping flat woven wire mesh 1A was fixed at a pitch of 5 mm by spot welding using a pressure electrode rod. Further, after winding the flat woven wire mesh 1A a total of three times, the outermost flat woven wire mesh 1A was fixed at a 5 mm pitch by spot welding using a pressure electrode rod. Furthermore, as shown in FIG. 8, the outermost tatami-woven wire mesh 1A was welded in the circumferential direction by seam welding.

[Filter Evaluation]
The characteristic evaluation of the 11 types of filters 10 for airbag inflators manufactured by the said process was performed. The compression test is carried out by fixing the airbag inflator filter 10 in a predetermined position with one end portion in the Y direction shown in FIG. 1 down, and applying a load from above in the Y direction shown in FIG. A load (N) when the filter 10 was compressed by 0.6 mm (hereinafter referred to as a load at a displacement of 0.6 mm) was measured. It can be said that the greater the load in the compression test, the better the strength of the airbag inflator filter 10. The pressure loss is a support plate provided with a pressure gauge that attaches a pipe for feeding air to one end portion in the Y direction shown in FIG. 1 of the filter for an air bag inflator and blocks the other end portion so that air does not leak. And 1 m ³ air per minute was passed from the inside of the air bag inflator filter 10 to the support plate.

  The evaluation results of the airbag inflator filter 10 are shown in Table 1. From the result shown in Table 1, the filter 10 for airbag inflators has confirmed the tendency for filter strength and a pressure loss to improve by raising a rolling rate.

  The airbag inflator filter 10 manufactured in Experimental Examples 1, 2, 3, 6, 7, 8, and 11 has a load in the range of 1800 N to 5000 N at a displacement of 0.6 mm and a pressure loss of 2.0 kPa to The range was 30 kPa. Therefore, the airbag inflator filter 10 manufactured using the flat woven wire mesh 1A that has been rolled in the range of 10% to 60% has a balanced filter strength and filter characteristics. .

  The airbag inflator filter 10 manufactured in Experimental Examples 4 and 9 had a load of 1600 N and 1200 N when the displacement was 0.6 mm, respectively, and a pressure loss of 1.0 kPa and 1.2 kPa, respectively. Therefore, the airbag inflator filter 10 manufactured using the flat woven wire mesh 1A rolled at a rolling rate of 5% is practical, but the rolling rate is in the range of 10% to 60%. Compared with the airbag inflator filter 10 manufactured using the rolled flat woven wire mesh 1A, the load at a displacement of 0.6 mm was low, so the filter strength was low.

  The airbag inflator filter 10 manufactured in Experimental Examples 5 and 10 had loads of 6000 N and 7800 N when the displacement was 0.6 mm, respectively, and the pressure loss was 32 kPa and 50 kPa, respectively. Therefore, the air bag inflator filter 10 manufactured using the flat woven wire mesh 1A rolled at a rolling rate of 70% is practical, but can withstand the gas pressure because of high pressure loss. There was a fear that there was not.

DESCRIPTION OF SYMBOLS 1 Tatami woven wire mesh 1A Tatami woven wire mesh 1B Twill woven wire mesh 2 End part of tatami woven wire mesh fixed by welding 4 End part of end of tatami woven wire mesh 5 Tatami woven wire mesh 6 A portion where tatami woven wire meshes are fixed by welding 7 Opening 10, 10A, 10B Airbag inflator filter 11 Horizontal line after rolling 11 'Horizontal line before rolling 12 Vertical line after rolling 12' Before rolling Vertical winding 20 Rotating winding jig 30 Inflator 31 Disc type case 32 Diffuser 33 Igniter 34 Gas generating agent 35 Storage part 36 Through hole

Claims (6)

A step of preparing a tatami woven wire mesh, a step of rolling the tatami woven wire mesh, and a step of winding the tatami woven wire mesh into a cylindrical shape after rolling,
The step of winding the tatami woven wire mesh after rolling into a cylindrical shape is a first step of fixing tatami woven wire meshes that overlap each other when wound once or twice; A second step of winding two or more times, and a third step of fixing the outermost tatami woven wire mesh after being wound once or twice or more and the tatami woven wire mesh adjacent to the outermost tatami woven wire mesh, A method for producing a filter for an air bag inflator, comprising:   The manufacturing method of the filter for airbag inflators of Claim 1 whose fixing means performed at the said 1st process and the said 3rd process is welding.   The manufacturing method of the filter for airbag inflators according to claim 1 or 2 whose rolling rate in the process of rolling said tatami-woven wire mesh is 10%-60%.   A hollow cylindrical body formed by rolling a tatami woven wire mesh that has been rolled and deformed to have a flat surface, the innermost tatami woven wire mesh of the hollow cylindrical body, and a tatami woven wire mesh adjacent to the tatami woven wire mesh The air bag inflator filter is characterized in that the outermost tatami woven wire mesh of the hollow cylindrical body and the tatami woven wire mesh adjacent to the tatami woven wire mesh are fixed.   The filter for airbag inflators according to claim 4 with which fixation of adjacent tatami woven wire mesh is performed by welding. 6. The airbag according to claim 4, wherein a pressure loss when air of 1 m ³ per minute is passed in a direction from the innermost circumferential side to the outermost circumferential side of the hollow cylindrical body is 0.1 kPa to 100 kPa. Inflator filter.