JP5261097B2 - Manufacturing method of airbag bag body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it easy to handle base cloth when sewing the outside circumferential parts of two pieces of the base cloth, and to enable the positional displacement of separate component parts to be prevented when mounting the separate components parts around a vent hole. <P>SOLUTION: A method of manufacturing the bag for the airbag formed by joining two pieces of the base cloth 31, 41 includes: a step of forming the vent hole 34 in one of the two pieces of the base cloth 31, 41; a step of joining a vent hole cover 60 for covering the vent hole 34 to the base cloth 31, in which the vent hole 34 is formed; a step of joining a cover guide member (a guide member) 70, which regulates the movement of the vent hole cover 60, to the base cloth 31, in which the vent hole 34 is formed; and a step of joining the peripheries of the two pieces of the base cloth 31, 41. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing an airbag bag body that regulates gas outflow by covering a vent hole with a vent hole cover.

  As a method for manufacturing an airbag bag body, a method is known in which a base fabric on one side of an airbag bag body positioned on the inflator side and a base fabric on the other side of the airbag bag body positioned on the occupant side are stitched together. Yes. In this type of airbag bag body, the base fabric on one side and the base fabric on the other side are stitched together to control internal pressure in the expansion process in order to adapt to various occupants, and gas outflow is caused by vent holes or the like. In order to obtain a function for adjusting the internal pressure by making it possible, it is common to process the base fabric.

As a vehicle airbag device that is the object of such a method of manufacturing an airbag bag body, after forming an edge portion between a base fabric on one side and a base fabric on the other side into a bag body, There is known a technique in which a base cloth is sewn in a spiral shape from an outer peripheral portion so that an internal pressure of a bag body in an expansion process can be adjusted (for example, refer to Patent Document 1).
JP 2005-193881 A

  In the vehicle airbag device of Patent Document 1, a vent hole is formed in one of the two base fabrics to release a gas when reaching a predetermined internal pressure or more, and the outer peripheral portions of the two base fabrics are sewn. A sewing part extending in a spiral shape from the center part of the airbag bag body toward the outer peripheral part is formed, and when the gas (fluid gas) generated by the inflator is supplied to the airbag bag body, When the sewing part is sequentially broken from the center part to the outer peripheral part by pressure, and the separation of the sewing part is completed while the inflation shape of the airbag bag body is regulated and the tension due to the internal pressure is applied to the protective surface of the bag body It develops into a final shape that is flat in the front-rear direction.

  In such a method of manufacturing an airbag bag body in a vehicle airbag device, the base fabric is easy to handle when the outer peripheral portions of the two base fabrics are sewn, and another component is attached around the vent hole. Therefore, consideration should be given to preventing misalignment of other components.

  The present invention facilitates handling of the base fabric when the outer peripheral portions of the two base fabrics are sewn, and can prevent misalignment of the separate components when attaching the separate components around the vent hole. It is an object of the present invention to provide a method for manufacturing an airbag bag body.

The invention according to claim 1 is a method of manufacturing an airbag bag body formed by joining two base fabrics, a step of forming a vent hole in one of the two base fabrics, and a vent hole A step of joining a vent hole cover covering the vent hole to the base fabric formed with a step, a step of joining a guide member for restricting the movement of the vent hole cover to the base fabric formed with the vent hole, and the periphery of the two base fabrics After joining the periphery of the two base fabrics, the ends of the vent hole cover are fixed to the two base fabrics by sewing the two base fabrics with a breakable suture. And a process .

According to a second aspect of the present invention, in the first aspect, each of the base cloth, the vent hole cover, and the guide member in which the vent hole is formed is formed of a sheet of the same material having friction characteristics different from each other, and the sheet is formed between the members. It arrange | positions so that the front surface and back surface of may face.

The invention according to claim 3 is a method of manufacturing an airbag bag body formed by joining two base fabrics, the step of forming a vent hole in one of the two base fabrics, and a vent hole A step of joining a vent hole cover covering the vent hole to the base fabric formed with a step, a step of joining a guide member for restricting the movement of the vent hole cover to the base fabric formed with the vent hole, and the periphery of the two base fabrics Each of the base fabric having the vent holes, the vent hole cover, and the guide member formed of a sheet of the same material having friction characteristics different from the front and back, and the front and back surfaces of the sheet between the members. It arrange | positions so that may oppose.

In the invention according to claim 1, a vent hole is formed in one of the two base fabrics, a vent hole cover that covers the vent hole is joined to the base fabric in which the vent hole is formed, and the base fabric in which the vent hole is formed is formed. Join the guide member that regulates the movement of the vent hole cover, join the periphery of the two base fabrics, join the periphery of the two base fabrics, and then suture the two base fabrics with a breakable suture As a result, the end portion of the vent hole cover is fixed to the two base fabrics . Therefore, after all the functional parts such as the vent hole cover and the guide member are arranged on one base fabric side, the two base fabrics are arranged. Cloth can be joined. Thereby, handling at the time of manufacture of an airbag bag body becomes easy. As a result, the productivity of the airbag bag body can be improved.
Further, according to the present invention, as described above, after joining the periphery of the two base fabrics, the end portions of the vent hole cover are joined to the two base fabrics by sewing the two base fabrics with a breakable suture. Since the vent hole cover is fixed to one base cloth, the end portion of the vent hole cover can be fixed to the two base cloths. As a result, the vent hole cover is not easily displaced.

In the invention according to claim 2, each of the base fabric, the vent hole cover, and the guide member in which the vent hole is formed is formed of a sheet of the same material having friction characteristics different from the front and back, and the front and back surfaces of the sheet between each member Therefore, the friction characteristics (slip characteristics) between the members can be made uniform. As a result, it is possible to manufacture an airbag bag body whose deployment characteristics are within a predetermined range.

In the invention according to claim 3 , a vent hole is formed in one of the two base fabrics, a vent hole cover that covers the vent hole is joined to the base fabric in which the vent hole is formed, and the vent is formed in the base fabric in which the vent hole is formed. Join the guide member that regulates the movement of the hole cover, join the periphery of the two base fabrics, and make the base fabric, the vent hole cover, and the guide member that have vent holes formed of the same material with different friction characteristics Since the sheet is formed so that the front and back surfaces of the sheet face each other, all functional parts such as the vent hole cover and guide member are arranged on one base fabric side. Two base fabrics can be joined. Thereby, handling at the time of manufacture of an airbag bag body becomes easy. As a result, the productivity of the airbag bag body can be improved.
Also, as noted above, each of the base fabric, vent hole cover and guide member in which the vent hole is formed is formed of a sheet of the same material having friction characteristics different from the front and back, and the front and back surfaces of the sheet are between the members. Since it arrange | positions so that it may oppose, the friction characteristic (sliding characteristic) between each member can be made uniform. As a result, it is possible to manufacture an airbag bag body whose deployment characteristics are within a predetermined range.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. "Front", "Rear", "Left", "Right", "Up", "Down" follow the direction seen from the driver, Fr is front, Rr is rear, Le is left, Ri is right Indicates.

  FIG. 1 is a perspective view of a vehicle employing a vehicle airbag device according to the present invention. The vehicle 10 is a vehicle in which a vehicle airbag device 13 is housed on a steering wheel 12 disposed in front of a driver's seat 11. The airbag device 13 introduces gas into an airbag bag body from an inflator (not shown) when collision energy is applied to the vehicle 10 and deploys the gas to the front side of the driver (hereinafter referred to as “occupant”). Is to be restrained and protected. Hereinafter, the airbag device 13 will be described in detail.

FIG. 2 is a view of the airbag bag body used in the vehicle airbag apparatus shown in FIG. 1 as viewed from the front of the vehicle. 3 is a cross-sectional view taken along line 3-3 of FIG. FIG. 4 is an exploded view of the airbag shown in FIG.
As shown in FIGS. 2 and 3, the airbag device 13 includes an inflator 20 (see FIGS. 3 and 4) indicated by an imaginary line and a retainer 22 (see FIGS. 3 and 4) arranged integrally with the steering wheel 12. ), A fixed link 23, and an airbag bag body 30. When the inflator 20 receives an ignition signal due to the collision energy acting on the vehicle 10, the inflator 20 ignites a gas generating agent (not shown) so as to ignite a high-pressure gas for bag expansion (hereinafter simply referred to as "gas"). Is generated and supplied to the airbag bag body 30. The inflator 20 has a mounting flange 21. The retainer 22 is a member that holds the airbag bag body 30 in a folded state and supports the inflator 20, and is provided on the steering wheel 12 (see FIG. 1). A bolt 24 formed integrally with a fixing ring 23 disposed in the airbag bag body 30 is inserted into a through hole formed in the mounting flange 21, and the nut is held with the retainer 22 sandwiched between the fixing ring 23 and the flange 21. The inflator 20 is fixed to the steering wheel 12 by fastening at.

  As shown in FIGS. 2 to 4, the airbag bag body 30 includes a first base cloth 31 and a second base cloth 41 each having a circular shape. The first base fabric 31 is a front seat positioned so as to face the steering wheel 12 when the airbag bag body 30 is deployed. The second base fabric 41 is a rear seat positioned so as to face the occupant when the airbag bag 30 is deployed. By overlapping the first and second base fabrics 31 and 41 and joining the outer peripheral portions 42 to each other (sewing integrally with the outer peripheral stitching portion 43), the airbag bag body 30 having a circular shape in front view is configured. Is done.

The first base fabric 31 is formed with one inflator insertion hole 32, a plurality of bolt holes 33, and one vent hole 34.
The inflator insertion hole 32 is a circular through hole that is disposed at the center CP of the first base fabric 31 and surrounds the inserted inflator 20. The gas generated by the inflator 20 is supplied to the inside of the airbag bag body 30. Hereinafter, the center CP of the first base fabric 31 is appropriately rephrased as “the center CP of the inflator insertion hole 32”.

  The plurality of bolt holes 33 are arranged around the inflator insertion hole 32. By overlapping the first base fabric 31 and the fixing ring 23 on the mounting flange 21 of the inflator 20 and screwing the bolt 24 (see FIG. 4) inserted into the bolt hole 33 to the mounting flange 21, the airbag bag body 30. Is attached to a retainer 22 on the steering wheel 12.

  The vent hole 34 is a circular through hole for releasing a part of gas to the outside when the airbag bag body 30 is inflated, and is a position offset by a predetermined distance from the center CP of the inflator insertion hole 32. It is arranged at HP (hole center HP). By releasing a part of the gas, it is possible to prevent the gas pressure (bag internal pressure) in the airbag bag body 30 from becoming excessive.

  As shown in FIGS. 2 and 3, the overlapped first and second base fabrics 31, 41 are a plurality of stitches, for example, three stitches, which are generally continuous in the circumferential direction from the central portion toward the outer peripheral portion. It is stitched by 51, 52, 53. These suture portions 51 to 53 are configured to be separated by sequentially breaking the suture from the central portion toward the outer peripheral portion due to the bag internal pressure when the airbag bag body 30 is inflated. Hereinafter, the separable stitching portions 51 to 53 are referred to as “breaking stitching portions 51 to 53”. Hereinafter, the breaking suture portions 51 to 53 will be described in detail.

  FIG. 5 is a detailed view of the breaking suture portion shown in FIG. 2 and shows a cross section in a state where the first and second base fabrics 31 and 41 are stitched together by the breaking suture portions 51 to 53. As shown in FIGS. 2 and 5, the three breaking suture portions 51 to 53 are portions that are spirally stitched from the stitching start point 54 near the center CP of the inflator insertion hole 32 to the stitching end point 55 of the outer peripheral portion 42. It is. Thus, the stitching start point 54 located at the radially inner end is directed to the center CP of the airbag bag body 30 (the center CP of the inflator insertion hole 32). For this reason, stress can be concentrated on the sewing start point 54 by the bag internal pressure.

  All of these three breaking suture portions 51 to 53 have the same configuration, and the length from the stitching start point 54 to the stitching end point 55 is the same, and they are arranged with a phase shift of 120 °. In the three breaking suture portions 51 to 53, the distances from the center CP of the inflator insertion hole 32 to the stitching start point 54 are all the same, and the distances from the center CP to the stitching end point 55 are all the same.

  Here, in FIG. 2, it is assumed that the azimuth in which the hole center HP is located is 0 ° with respect to the center CP of the inflator insertion hole 32, and the angle increases clockwise in the figure. The straight line SL1 extending from the center CP of the inflator insertion hole 32 through the center of the hole center HP to the azimuth of 0 ° is referred to as a reference line SL1. A straight line orthogonal to the reference line SL1 on the surface of the first base fabric 31 is referred to as an orthogonal reference line SL2.

  The first breaking suture portion 51 has a azimuth 0 ° as a stitching start point 54, and is slightly stitched outward in the radial direction while slightly extending outward from the stitching start point 54, and then stitched in a circular arc shape. It is sewn in a spiral shape by an angle of 120 °, and an azimuth of 120 ° is a stitching end point 55. The stitching start point 54 is located radially outward from the vent hole 34. The stitching end point 55 is formed before reaching the outer peripheral edge of the base fabric 31, 41, thereby allowing gas to flow between the end point and the outer peripheral edge.

  Similarly, the second breaking suture part 52 is stitched in a spiral shape by 240 ° in the counterclockwise direction along the outer periphery of the first breaking suture part 51 with the azimuth 120 ° as the stitching start point 54. The azimuth 240 ° is the stitching end point 55. The third breaking suture portion 53 has a direction 240 ° as a sewing start point 54, and is sutured in a spiral shape by 240 ° counterclockwise along the outer periphery of the second breakage suture portion 52. ° is the stitching end point 55. The breaking suture portions 51, 52, 53 are spaced apart from each other with a predetermined interval in the radial direction. This interval gradually decreases as the stitching start point 54 advances to the stitching end point 55.

  6 is a cross-sectional view taken along line 6-6 of FIG. As described above, each of the breaking suture portions 51 to 53 is configured to be separated by sequentially breaking the suture thread 56 from the central portion toward the outer peripheral portion. The suture thread 56 includes a first thread 56a and a second thread 56b. The first yarn 56a is not weakly colored so as to be broken by a bag internal pressure of a predetermined level or more, for example, tensile strength (force required for pulling and breaking, breaking load) of 20N to 60N is not applied. Made of filament yarn. On the other hand, the second thread 56b is a thread that guides the first thread 56a in the stitching direction of the breaking suture portions 51, 52, and 53, and is not broken by the bag internal pressure when the airbag bag body 30 is inflated. In addition, the tensile strength is set larger than that of the first yarn 56a.

  For this reason, the 1st thread | yarn 56a is fractured | ruptured by the tension | tensile_strength which acts on a 1st thread | yarn based on the bag internal pressure more than predetermined. Moreover, the first thread 56a is guided in the stitching direction by the second thread 56b. For this reason, the breaking strength of the first thread 56a is kept substantially constant at any location in each of the breaking suture portions 51 to 53. Accordingly, the first yarn 56a is appropriately and sequentially broken from the central portion toward the outer peripheral portion of the first and second base fabrics 31 and 41. The airbag bag body 30 can be inflated more smoothly with good timing by the gas supplied from the inflator 20. For this reason, the change of the bag internal pressure can be controlled more appropriately. And the internal pressure characteristic of the airbag bag body 30 after starting supply of gas from the inflator 20 to the airbag bag body 30 can be made still more exact.

  The filament yarn constituting the first yarn 56a is a yarn composed of filaments (continuous continuous fibers) and has no or almost no twist. Since there is no twist, there is little variation in breaking load in the length direction of the yarn. Accordingly, the first yarn 56a is accurately and sequentially broken from the central portion toward the outer peripheral portion of the first and second base fabrics 31 and 41 by a bag internal pressure of a predetermined level or more.

As shown in FIGS. 2 to 4, the airbag bag body 30 includes a vent hole cover 60, a cover guide member 70, and first, second, and third reinforcing sheets 81, 82, and 83. Each of the reinforcing sheets 81 to 83 has a through-hole having substantially the same diameter as the inflator insertion hole 32.
The first reinforcing sheet 81 is superimposed on the surface of the first base cloth 31 (the face facing the mounting flange 21), and further, the second reinforcing sheet 82, the vent hole cover 60, The cover guide member 70 and the third reinforcing sheet 83 are overlapped in this order, and all these members are integrally stitched around the inflator insertion hole 32.

  The first and third reinforcing sheets 81 and 83 are annular (hollow circular) members, and reinforce the periphery of the inflator insertion hole 32 in the first base cloth 31. The second reinforcing sheet 82 is an elongated member, and reinforces the periphery of the inflator insertion hole 32 and the periphery of the vent hole 34 in the first base cloth 31. The mounting flange 21 is overlapped with the first base fabric 31 via the first reinforcing sheet 81. The fixing ring 23 is overlaid on the first base fabric 31 via the third reinforcing sheet 83.

  The first and second base fabrics 31 and 41, the vent hole cover 60, the cover guide member 70, and the first, second, and third reinforcing sheets 81, 82, and 83 are all made of the same material and the same thickness ( Flexible panel). This cloth has mutually different friction characteristics (friction resistance) on the front surface (one surface) and the back surface (the other surface). For example, the friction characteristics are different between the front and back surfaces by applying a silicon coating only to one side of the cloth. The first base cloth 31, the second base cloth 41, the vent hole cover 60, and the cover guide member 70 are arranged so that the front and back surfaces of the first base cloth 31, the second base cloth 41, and the cover guide member 70 face each other alternately.

  For example, the friction resistance of the first base fabric 31 is smaller on the front surface (surface facing the mounting flange 21) than on the back surface. The vent hole cover 60 has a surface with a small frictional resistance facing a back surface (a surface with a large frictional resistance) of the first base fabric 31. The cover guide member 70 has a surface with a small frictional resistance facing a back surface (a surface with a high frictional resistance) of the vent hole cover 60. The surface of the second base fabric 41 having a small frictional resistance faces the back surface (a surface having a high frictional resistance) of the cover guide member 70.

  FIG. 7 is an enlarged view of a main part of the airbag bag body shown in FIG. 2, and shows a state where the first base cloth 31 shown by an imaginary line is seen through. As shown in FIGS. 2 to 4 and 7, the vent hole cover 60 is a member that closes the vent hole 34 in a normal state until a bag pressure of a predetermined level or more is applied to the airbag bag body 30. The vent hole cover 60 is formed in a substantially T-shape when viewed from the front, and includes an annular base 61, a vertical belt-like extension portion 62, and a horizontal belt-like orthogonal portion 63. The vent hole cover 60 is symmetrical with respect to the reference line SL1.

  More specifically, the base 61 of the vent hole cover 60 is an annular portion located at the center CP of the inflator insertion hole 32, and has a through hole having substantially the same diameter as the inflator insertion hole 32. The base 61 is integrally stitched to the first base cloth 31 around the inflator insertion hole 32.

  The extended portion 62 of the vent hole cover 60 is a vertical strip portion having a predetermined width extending along the reference line SL1 from the base portion 61 to the vent hole 34 along the back surface of the first base fabric 31.

  The orthogonal portion 63 of the vent hole cover 60 is a horizontal band-shaped portion having a predetermined width extending from the tip portion of the extending portion 62 to the left and right with respect to the reference line SL1 along the back surface of the first base fabric 31. is there. That is, it extends in a direction perpendicular to the extending part 62. In FIG. 7, the upper edge of the orthogonal part 63 is formed substantially parallel to the orthogonal reference line SL2. Further, the lower edge of the orthogonal part 63 is formed in a slightly tapered shape that protrudes toward the center CP side of the inflator insertion hole 32.

  More specifically, the orthogonal part 63 includes a pair of left and right belt-like parts 64 and 64 extending in directions away from the reference line SL1. The front end portions 64a and 64a of the left and right belt-like portions 64 and 64, that is, both end portions of the orthogonal portion 63 are stitched to the first and second base fabrics 31 and 41 by the respective breaking stitching portions 51 to 53. .

  The intersection of the vertical belt-like extension part 62 and the horizontal belt-like orthogonal part 63 is located at the hole center HP. The distance from the corner portion (the T-shaped corner portion of the vent hole cover 60) between the edge of the extension portion 62 and the edge of the orthogonal portion 63 to the edge of the vent hole 34 is larger than the other portions of the vent hole cover 60. It is set small.

  The cover guide member 70 is a member that guides the position of the orthogonal portion 63 of the vent hole cover 60 so as not to shift when the orthogonal portion 63 moves in the direction of the reference line SL1. The cover guide member 70 is formed in a substantially T-shape when viewed from the front, and includes an annular base 71 and a lateral belt-shaped guide 72. This cover guide member 70 is symmetrical with respect to the reference line SL1.

  More specifically, the base 71 of the cover guide member 70 is an annular portion located at the center CP of the inflator insertion hole 32, and has a through hole having substantially the same diameter as the inflator insertion hole 32. The base 71 is integrally stitched to the first base cloth 31 around the inflator insertion hole 32. By extending the base 71 to the vicinity of the inflator 20, the relative position between the inflator 20 and the cover guide member 70 can be easily adjusted, and the manufacturing accuracy can be improved.

  The guide portion 72 is a horizontal band-shaped portion having a predetermined width extending from the outer peripheral portion of the base portion 71 along the back surface of the first base fabric 31 both to the left and right with respect to the reference line SL1. The guide portion 72 is superimposed on the first base cloth 31 from above the orthogonal portion 63 of the vent hole cover 60, and is guided by the first, second, and third stitching portions 73 to 75 for guide. Only the base fabric 31 is sewn together. The movement (sliding) of the orthogonal part 63 of the vent hole cover 60 is guided and the moving direction of the orthogonal part 63 is regulated by the three guide sewing parts 73 to 75 (guide sewing parts 73 to 75). The The left and right tips 72a, 72a of the guide portion 72 are opened without being sewn and extended to the vicinity of the breaking suture portions 51 to 53.

  As shown in FIG. 7, the first guide stitching portion 73 is a stitched portion from the vicinity of the left tip 72 a to the vicinity of the right tip 72 a along the upper edge of the guide portion 72. The first guide stitching portion 73 is stitched substantially parallel to the upper edge of the guide portion 72.

  The second guide stitching portion 74 is sewn from the vicinity of the left end 72a of the guide portion 72 to the vicinity of the edge of the extending portion 62 of the vent hole cover 60 along the left lower edge of the guide portion 72. Part. The second guide stitching portion 74 is stitched to the lower edge of the left side of the guide portion 72 so that the extending portion 62 side is slightly closer to the inflator insertion hole 32.

  The third guide stitching portion 75 is stitched from the vicinity of the right tip 72a of the guide portion 72 to the vicinity of the edge of the extension portion 62 of the vent hole cover 60 along the right lower edge of the guide portion 72. Part. The third guide stitching portion 75 is stitched to the lower edge of the right side of the guide portion 72 so that the extending portion 62 side is slightly inclined toward the inflator insertion hole 32.

  These guide stitching portions 73 to 75 have stress concentration suppressing portions 76 and 76 at stitched ends on both sides, respectively. As shown in FIG. 7, the stress concentration suppressing portions 76, 76 on both sides are portions where guide stitching portions 73 to 75 are further stitched in a loop shape in the direction away from the vent hole cover 60 at each stitching end. In the present embodiment, the stress concentration suppressing portions 76 and 76 are formed in a substantially oval shape in a front view that is elongated in the direction along the respective guide stitching portions 73 to 75. For this reason, each stitching end exhibits an arc shape.

  As shown in FIG. 7, when the airbag bag 30 is viewed from the front, the stress concentration suppressing portions 76 and 76 are in the following relationship with respect to the guide stitching portions 73 to 75. That is, the stress concentration suppressing portions 76 and 76 of the first guide stitching portion 73 are formed on the first guide stitching portion 73. The stress concentration suppressing portions 76 and 76 of the second and third guide stitching portions 74 and 75 are formed below the second and third guide stitching portions 74 and 75.

  As described above, the stress concentration suppressing portions 76 and 76 are provided at the respective suture ends of the guide stitching portions 73 to 75. When the vent hole cover 60 moves between the first and second guide stitching portions 73 and 74, or when the vent hole cover 60 moves between the first and third guide stitching portions 73 and 75, the vent hole The edge of the cover 60 moves while rubbing the stress concentration suppressing portions 76 and 76. Since these stress concentration suppressing portions 76 and 76 are formed in an arc shape, the stress is suppressed from concentrating on this portion. For this reason, there is no fear that each stitching end in the guide stitching portions 73 to 75 is rubbed against the vent hole cover 60 and peeled off. Further, the vent hole cover 60 and the cover guide member (guide member) 70 do not interfere with each other. Therefore, the vent hole cover 60 can move smoothly.

  The length from the reference line SL1 to the distal end 72a of the guide portion 72 is set shorter than the length from the reference line SL1 to the distal end portion 64a of the strip-like portion 64. However, the length from the reference line SL1 to the distal end 72a of the guide portion 72 is set to be longer than the length from the distal end 72a to the distal end portion 64a of the strip-shaped portion 64. Therefore, it is assumed that the breaking stitches 51 to 53 break and the tip 64a is unconstrained, and the band 64 is folded back to the back side of the guide part 72 while the band 64 moves to the reference line SL1 side. However, the vent hole 34 is not blocked by the tip 64a.

  Furthermore, the left and right tips 72a, 72a of the guide portion 72 are formed in an inclined shape that is inclined with respect to the reference line SL1 (inclined with respect to the orthogonal portion 63 of the vent hole cover 60). Therefore, even when the belt-like portion 64 of the vent hole cover 60 is moved to the reference line SL1 side, even if the belt-like portion 64 is folded back to the back side of the guide portion 72, the belt-like portion 64 is folded obliquely along the inclined tip 72a. become. For this reason, the folded state of the band-like portion 64 can be solved very easily. The belt-like portion 64 can move smoothly in the guide portion 72.

  Furthermore, the guide part 72 has an opening 77 located at the hole center HP. That is, the guide portion 72 has an opening 77 at a portion corresponding to the vent hole 34. The opening 77 is a circular hole that is substantially the same type as the vent hole 34.

Next, the operation of the airbag device 13 will be described.
When a collision energy of a predetermined level or more is applied to the vehicle 10 (see FIG. 1), the inflator 20 shown in FIG. 3 receives an ignition signal and ignites the gas generating agent, thereby generating gas, and the airbag bag. Supply to body 30. The airbag bag body 30 housed in a folded state on the steering wheel 12 (see FIG. 1) starts to inflate with gas. In the process of inflating the airbag bag body 30, a cover (not shown) attached to the steering wheel 12 is broken from the tear line to form an opening for the airbag bag body 30 to expand and deploy. As a result, the airbag bag body 30 starts to be deployed in the vehicle interior.

  As shown in FIGS. 2 and 3, the airbag bag body 30 has the first and second base fabrics 31 and 41 integrally stitched together by three breaking suture portions 51 to 53. For this reason, the inflation volume of the airbag body 30 is regulated at the initial stage of deployment, and the membrane pressure distribution quickly reaches a uniform membrane pressure distribution within the regulated volume between the center and the breaking suture portions 51 to 53. At this time, when the occupant is present at a position close to the steering wheel 12 and starts to contact, the rupture of the breaking suture portions 51 to 53 progresses with the increase of the internal pressure, thereby suppressing the amount of increase in the internal pressure and softly occupant. Can be restrained.

  Even when there is no contact with the occupant, the three breaking suture portions 51 to 53 move from the stitching start point 54 to the stitching end point according to the increase in the bag internal pressure in the airbag bag body 30 due to gas inflow from the inflator 20. It is sequentially broken toward 55. For this reason, the airbag body 30 gradually expands its volume while maintaining an appropriate bag internal pressure, and is deployed so as to have a predetermined shape.

  By the way, as shown in FIG. 7, the distal end portions 64 a and 64 a of the left and right belt-like portions 64 and 64 in the vent hole cover 60 are formed by first and second base fabrics 31 and 41 by the breaking suture portions 51 to 53. Is sewn to. For this reason, the front end portions 64 a and 64 a are restrained by the first and second base fabrics 31 and 41 until the breaking portions 51 to 53 are broken. Since the vent hole 34 is closed by the vent hole cover 60, the gas in the airbag bag body 30 is prevented from escaping to the outside. As a result, the gas pressure in the airbag bag body 30 rises quickly, and the gas pressure is appropriately maintained. The gas pressure in the airbag bag body 30 acts on the central portion of the orthogonal portion 63 of the vent hole cover 60 through the opening 77 of the cover guide member 70.

  Thereafter, when all of the breaking suture portions 51 to 53 are broken at the end of deployment of the airbag body 30, the restraints of the end portions 64a and 64a of the belt-like portions 64 and 64 are released. The central part of the orthogonal part 63 of the vent hole cover 60 is pushed out from the vent hole 34. As it is pushed out, the left and right belt-like parts 64, 64 are guided by the guide part 72 (guided by the guide stitching parts 73 to 75) and move toward the vent hole 34. As a result, the vent hole 34 is opened. Thus, even after the relaxation of the pressure increase by each breaking suture portion is completed, the excess gas in the airbag bag body 30 is discharged from the vent hole 34, so that the airbag bag body 30 has a maximum shape. After that, excessive increase in the bag internal pressure of the airbag bag body 30 is prevented.

Hereinafter, an example of the procedure of the manufacturing method of an airbag bag body is demonstrated.
FIG. 8 is an explanatory diagram of the first half showing an example of the procedure of the method for manufacturing an airbag bag according to the present invention.
In (a), it is a manufacturing method of the airbag bag body formed by joining two base fabrics 31 and 41, and the 1st base fabric 31A and 2nd before processing which have a predetermined outer diameter A base cloth 41 is prepared.

  In (b), a vent hole 34 is formed in one of the two base cloths 31 and 41 (first base cloth 31A before processing). At the same time, an inflator insertion hole 32 for inserting the inflator 20 and four bolt holes 33 for attaching the airbag bag body 30 to the inflator 20 are formed.

As described above, the first base cloth 31, the second base cloth 41, the vent hole cover 60, and the cover guide member 70 are made of a material (sheet) having a silicon coating only on one side. The first base fabric 31, the vent hole cover 60, and the cover guide member 70 are disposed so that the front surface and the back surface of the base fabric 31 face each other alternately, and the first base fabric 31 is a finished product of the airbag bag body 30. The inner surface of the second base fabric 41 is manufactured as the coating surface 31a and the outer surface is manufactured as the non-coating surface 31b. The inner surface of the second base fabric 41 is manufactured as the coating surface 41a and the outer surface is manufactured as the non-coating surface 41b. In addition, the airbag bag body 30 is turned upside down from the inflator insertion hole 32 so that the outer peripheral stitched portion 43 is located inside after the outer peripheral stitched portion 43 is formed.
Accordingly, in (b), the first base fabric 31 is set with the coating surface 31a on the paper surface side, and the non-coating surface 41b with the paper surface side of the second base fabric 41.

  In (c), the second reinforcing sheet 82 and the vent hole cover 60 are disposed on the coating surface 31a of the first base cloth 31, and the first non-coating surface 31b (see FIG. 3) of the first base cloth 31 is first. The reinforcing sheet 81 is arranged, and the first and second reinforcing sheets 81 and 82 and the vent hole cover 60 are stitched to the first base cloth 31. The first and second reinforcing sheets 81 and 82 and the coating surfaces 81a, 82a and 60a of the vent hole cover 60 are directed and stitched to the surface side of the paper.

FIG. 9 is an intermediate explanatory view showing an example of the procedure of the method for manufacturing an airbag bag according to the present invention.
In (a), the cover guide member 70 is disposed on the coating surface 31 a of the first base fabric 31 so as to cover the vent hole cover 60, and the third reinforcing sheet 83 is disposed on the cover guide member 70. To do. The coating surface 70a of the cover guide member 70 and the coating surface 83a of the third reinforcing sheet 83 are directed to the surface side of the paper.

  As shown in FIGS. 8 (b), 8 (c), and 9 (a), the air bag body manufacturing method includes a base fabric 31, a vent hole cover 60, and a cover guide formed with a vent hole 34. It can be said that each of the members (guide members) 70 is formed of a sheet of the same material having friction characteristics different from each other, and is arranged so that the front surface and the back surface of the sheet face each other between the members 31, 60, and 70. Thereby, the friction characteristic (slip characteristic) between each member 31,60,70 can be made uniform. As a result, it is possible to manufacture the airbag bag body 30 with the deployment characteristics within a predetermined range.

  In (b), the cover guide member 70 and the third reinforcing sheet 83 are stitched to the first base cloth 31. Further, guide sewing portions 73 to 75 are formed in the cover guide member 70, and stress concentration suppressing portions 76 and 76 are formed in the guide sewing portions 73 to 75, respectively.

  In (c), the uncoated surface 31b (see FIG. 3) of the first base fabric 31 in which the vent hole cover 60 and the cover guide member 70 are stitched is indicated by an arrow on the uncoated surface 41b of the second base fabric 41. Stack as a1. Thereby, the coating surfaces 60 a and 70 a of the vent hole cover 60 and the cover guide member 70 are also aligned with the non-coating surface 41 b of the second base cloth 41.

FIG. 10 is an explanatory diagram of the latter half showing an example of the procedure of the method for manufacturing an airbag bag according to the present invention.
In (a), the uncoated surface 31b (see FIG. 3) of the first base fabric 31 to which the vent hole cover 60 and the cover guide member 70 are sewn is overlapped on the uncoated surface 41b of the second base fabric 41. Further, the periphery of the first and second base fabrics 31 and 41 is sewn as shown by an arrow a2.
The second base cloth 41 is pulled out from the inflator insertion hole 32 to the front side of the drawing.

  In (b), as a result of pulling out the second base cloth 41 from the inflator insertion hole 32 to the front side of the drawing, the first and second base cloths 31, 41 are turned over. The vent hole cover 60, the cover guide member 70, and the stitching portions 43 (see FIG. 3) on the outer periphery of the first and second base fabrics 31 and 41 are accommodated inside the airbag body 30, and the first and second The non-coating surfaces 31b and 41b are exposed on the base fabrics 31 and 41 (see also FIG. 3). That is, the front and back of the bases 31 and 41 are reversed.

In (c), the first and second base fabrics 31 and 41 (refer to FIG. 3 for 41) are a plurality of strips and three stitched portions 51 that are continuous in the circumferential direction from the central portion toward the outer peripheral portion. Suture (spiral sewing) is performed by 52 and 53. In the stitched portions 51, 52, 53, as shown in FIG. 6, a breakable suture 56 (see FIG. 6) is used.
Further, both end portions of the vent hole cover 60 are sewn to the first and second base fabrics 31 and 41 at the stitching portions 51, 52 and 53.

  In the manufacturing method of the airbag bag body, after joining the periphery of the two base fabrics 31 and 41, the two base fabrics 31 and 41 are stitched with a breakable suture 56 (see FIG. 6), Since the step of fixing the end portion of the vent hole cover 60 to the two base cloths 31 and 41 is provided, two end portions of the vent hole cover 60 are fixed after the vent hole cover 60 is fixed to one base cloth 31. It can fix to the base fabrics 31 and 41. As a result, the vent hole cover 60 is not easily displaced.

  As shown in FIGS. 3 and 8 to 10, the method for manufacturing an airbag bag body is a method for manufacturing an airbag bag body formed by joining two base fabrics 31 and 41. A step of forming a vent hole 34 in one of the two base fabrics 31 and 41, a step of joining a vent hole cover 60 covering the vent hole 34 to the base fabric 31 in which the vent hole 34 is formed, and a vent hole 34 It can be said to include a step of joining a cover guide member (guide member) 70 for restricting the movement of the vent hole cover 60 to the formed base fabric 31 and a step of joining the periphery of the two base fabrics 31 and 41.

  In the method of manufacturing the airbag bag body, a vent hole 34 is formed in one of the two base fabrics 31 and 41, and a vent hole cover 60 that covers the vent hole 34 is joined to the base fabric 31 in which the vent hole 34 is formed. Since the guide member 70 for restricting the movement of the vent hole cover 60 is joined to the base cloth 31 in which the vent hole 34 is formed, the periphery of the two base cloths 31 and 41 is joined. The two base fabrics 31 and 41 can be joined after all the functional parts such as the vent hole cover 60 and the guide member 70 are arranged on the side. Thereby, handling at the time of manufacture of air bag body 30 becomes easy. As a result, the productivity of the airbag bag body 30 can be improved.

  In addition, the manufacturing method of the airbag bag body which concerns on this invention stitches the vent hole cover 60 and the cover guide member 70 to the 1st base fabric 31, as shown in FIG.8 (c) and FIG.9 (b). Although the process is a separate process, the process is not limited to this, and the vent hole cover 60 and the cover guide member 70 may be sewn together in the same process. At this time, the vent hole cover 60 and the cover guide member 70 can be temporarily assembled.

  The present invention is suitable for manufacturing a vehicle airbag device that regulates gas outflow by covering a vent hole with a vent hole cover.

1 is a perspective view of a vehicle that employs a vehicle airbag device according to the present invention. It is the figure which looked at the airbag bag body used for the airbag apparatus for vehicles shown in FIG. 1 from the vehicle front. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 3 is an exploded view of the airbag bag body shown in FIG. 2. FIG. 3 is a detailed view of a breaking suture portion shown in FIG. 2. FIG. 6 is a sectional view taken along line 6-6 of FIG. It is a principal part enlarged view of the airbag bag body shown in FIG. It is explanatory drawing of the first half which shows an example of the procedure of the manufacturing method of the airbag bag body which concerns on this invention. It is intermediate explanatory drawing which shows an example of the procedure of the manufacturing method of the airbag bag body which concerns on this invention. It is explanatory drawing of the second half which shows an example of the procedure of the manufacturing method of the airbag bag body which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 13 ... Vehicle airbag apparatus, 30 ... Air bag body, 31, 41 ... 1st, 2nd base fabric, 34 ... Vent hole, 60 ... Vent hole cover, 70 ... Guide member (cover guide member).

Claims (3)

A method for producing an airbag bag body formed by joining two base fabrics,
Forming a vent hole in one of the two base fabrics;
Bonding a vent hole cover that covers the vent hole to the base fabric on which the vent hole is formed;
Joining a guide member that regulates movement of the vent hole cover to the base fabric on which the vent hole is formed;
Joining the periphery of the two base fabrics ;
Fixing the ends of the vent hole cover to the two base fabrics by joining the periphery of the two base fabrics and then sewing the two base fabrics with a breakable suture;
The manufacturing method of the airbag bag body characterized by including this. Each of the base fabric, the vent hole cover and the guide member formed with the vent hole is formed of a sheet of the same material having friction characteristics different from the front and back,
The method for manufacturing an airbag bag body according to claim 1 , wherein the sheet is disposed so that a front surface and a back surface of the sheet face each other. A method for producing an airbag bag body formed by joining two base fabrics,
Forming a vent hole in one of the two base fabrics;
Bonding a vent hole cover that covers the vent hole to the base fabric on which the vent hole is formed;
Joining a guide member that regulates movement of the vent hole cover to the base fabric on which the vent hole is formed;
Bonding the periphery of the two base fabrics,
Each of the base fabric, the vent hole cover and the guide member formed with the vent hole is formed of a sheet of the same material having friction characteristics different from the front and back,
A method for manufacturing an airbag bag body, wherein the front and back surfaces of the sheet are arranged to face each other between the members.

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