JP2006347354A - Air bag apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the foldability of an air bag having a cover opening a vent hole in an expanded state. <P>SOLUTION: A slit 39a extending in the direction nearly perpendicular to the straight line connecting two fixing portions 40, 41 is formed between at least the one fixing portion 41 and the vent hole 37b by fixing a cloth cover 39 on the inside surface of a base cloth 37 at the two fixing portions 40, 41 arranged on both sides of the vent hole 37b. When the air bag expands and a tensile stress is applied to the cover 39, the slit 39a is stretched and the tensile stress is partially reduced. As a result, the cover 39 is partially lifted from the base cloth 37 and the vent hole 37b is opened. Because both ends of the cover 39 are fixed to the base cloth 37, the position of the cover 39 does not shift from the position of the vent hole 37b in folding the air bag 32, and the working efficiency of folding work is improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  According to the present invention, a vent hole formed in a base fabric of an airbag that is inflated upon supply of a gas in the event of a vehicle collision is covered with a cover from the inner surface side of the base fabric, and the cover is subjected to an increase in the internal pressure of the airbag. The present invention relates to an airbag device to be opened.

Cover the vent hole with a cover whose one end is fixed to the inner surface of the airbag base fabric by sewing, and when the inflation of the airbag is completed and the internal pressure rises above a predetermined value, the cover has the vent hole at the other end. Patent Document 1 listed below discloses a technique for exhausting excess gas from an airbag to prevent an excessive increase in internal pressure by passing through and opening the vent hole.
Japanese Patent Laid-Open No. 10-71923

  By the way, in the above-mentioned conventional one, only one end of the cover is fixed to the base fabric and the other end can move freely, so be careful not to remove the other end of the cover from the vent hole when folding the airbag. There is a problem that the workability of the airbag folding work is remarkably lowered.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to improve the ease of folding an airbag including a cover that opens a vent hole when inflated.

  In order to achieve the above object, according to the first aspect of the present invention, the vent hole formed in the base fabric of the airbag that receives the gas supply and inflates when the vehicle collides is formed from the inner surface side of the base fabric. In an airbag device that covers with a cover and opens the cover in accordance with an increase in the internal pressure of the airbag, the cover is fixed to the base fabric by two fixing portions located on both sides of the vent hole and at least one of the fixings There is proposed an airbag device characterized by having a slit extending in a direction substantially orthogonal to a straight line connecting two fixed portions between the portion and the vent hole.

  According to the invention described in claim 2, in addition to the structure of claim 1, a plurality of the slits are provided in a direction substantially orthogonal to a straight line connecting the two fixing portions. A bag device is proposed.

  According to a third aspect of the present invention, in addition to the configuration of the second aspect, the width of one fixed portion side of the cover is formed wider than the width of the other fixed portion side, and the slit is covered. An airbag device is proposed which is formed only on the one fixed portion side.

  According to a fourth aspect of the present invention, in addition to the structure of any one of the first to third aspects, the slit is opened at the edge of the cover. Is proposed.

  According to the invention described in claim 5, in addition to the structure of any one of claims 1 to 3, a notch that faces the end of the slit is formed in the edge of the cover. A featured airbag device is proposed.

  In addition, the 2nd base fabric 37 of an Example respond | corresponds to the base fabric of this invention.

  According to the configuration of claim 1, the cover is fixed to the base fabric with two fixing portions located on both sides of the vent hole, and a straight line connecting the two fixing portions between at least one fixing portion and the vent hole. Since a slit extending in a direction substantially perpendicular to the cover is formed, when the airbag is inflated and tension is applied to the cover, the slit is stretched and the tension is partially reduced, so the cover is partially lifted from the base fabric. The vent hole is opened. Since both ends of the cover are fixed to the base fabric, the position of the cover is not displaced from the vent hole when the airbag is folded, and the working efficiency of the airbag folding work is improved.

  According to the configuration of the second aspect, since a plurality of slits are provided in a direction substantially orthogonal to the straight line connecting the two fixing portions, the high tension portion and the low tension portion are alternately generated on the cover so that the cover is It can be effectively lifted from the inner surface of the base fabric.

  According to the configuration of the third aspect, the width of the one fixed portion side of the cover is formed wider than the width of the other fixed portion side, and the slit is formed only on the one fixed portion side of the cover. It is possible to secure the maximum length of the slit without making it, and to sufficiently open the both end edges of the cover so that the vent hole can be surely opened.

  According to the fourth aspect of the present invention, since the slit is opened to the edge of the cover, when the airbag is inflated and tension is applied to the cover, the edge of the cover can be lifted freely from the base fabric. The vent hole can be opened reliably.

  According to the fifth aspect of the present invention, since the notch that faces the end of the slit is formed at the edge of the cover, the break that started from the notch is communicated with the slit when the airbag is inflated and tension is applied to the cover. The vent hole can be surely opened by allowing the edge of the cover to float freely from the base fabric.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 6 show a first embodiment of the present invention. FIG. 1 is a perspective view of a front part of a passenger compartment of an automobile, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is a front view of the airbag, FIG. 5 is an explanatory view of the action of the airbag when it is inflated, and FIG. 6 is a sectional view taken along line 6-6 of FIG.

  As shown in FIG. 1, a driver seat airbag module 13 is housed in a steering wheel 12 disposed in front of the driver seat 11.

  As shown in FIG. 2, the steering wheel 12 includes a boss portion 16 fixed to the rear end of the steering shaft 14 with a nut 15, a front cover 17 fixed to the boss portion 16, and a bolt 18 on the rear surface of the front cover 17. .., A plurality of spoke portions 20 that extend radially from the front cover 17, and a steering wheel body portion 21 that continues to the outer periphery of the spoke portions 20. A retainer 22 is fastened together with bolts 18 to the inner peripheral surface of the rear cover 19, and the airbag module 13 is supported by the retainer 22. On the inner surface of the rear cover 19, a thin tear line 19a that is broken when the airbag 32 is inflated is formed.

  The airbag module 13 includes an inflator 31 filled with a propellant that generates high-pressure gas by combustion, an airbag 32 formed by sewing a base fabric, and a fixing ring 33 that fixes a base portion of the airbag 32. The flange 31a of the inflator 31 and the fixing ring 33 are overlapped on the front surface and the rear surface of the retainer 22, and are fastened with bolts 34 and nuts 35. At this time, the base portion of the airbag 32 is sandwiched and fixed between the rear surface of the retainer 22 and the front surface of the fixing ring 33.

  As shown in FIGS. 3 and 4, the circular airbag 32 includes a first base fabric 36 on the rear side (side facing the occupant) and a second base fabric 37 on the front side superimposed on the front surface thereof. The first and second base fabrics 36 and 37 are sewn together by a sewing portion 38 on the outer periphery. The second base fabric 37 of the airbag 32 has a circular opening 37a surrounding the inflator 31, a vent hole 37b through which a part of gas escapes when the airbag 32 is inflated, and four bolt holes 37c through which the bolts 34 pass. ... is formed. Accordingly, the airbag 32 is supported by the retainer 22 at the central portion of the second base fabric 37, and the gas generated by the inflator 31 is supplied into the airbag 32 from the central opening 37 a of the second base fabric 37.

  A cloth cover 39 is provided on the inner surface side of the second base cloth 37 so as to cover the vent hole 37b. The cover 39 has a generally trapezoidal shape, and the upper bottom in the radial direction is sewn at a fixing portion 40 along the outer peripheral portion of the second base cloth 37, and the lower bottom in the radial direction is fixed closer to the center of the second base cloth 37. Sewing is performed at the portion 41. Two slits 39a and 39a extending in a direction orthogonal to a straight line connecting both the fixing portions 40 and 41 are formed in series between the edge of the vent hole 37b and the fixing portion 41 on the radially inner side. When no tension is applied to the cover 39, the distance between the two fixing portions 40 and 41 is L (see FIG. 5).

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  When a collision of the vehicle is detected by the acceleration sensor, the inflator 31 is actuated by a command from the electronic control unit, and the gas generated by the inflator 31 flows from the opening 37a in the center of the second base fabric 37, so that the airbag 32 is Inflate. Since the cover 39 covering the vent hole 37b is arranged on the inner surface side of the second base cloth 37, the cover 39 is pressed against the inner surface of the second base cloth 37 so as to close the vent hole 37b in the process of inflating the airbag 32. Therefore, gas leakage from the vent hole 37b is suppressed.

  When the inflation of the airbag 32 is completed and the internal pressure increases to a predetermined value or more, a tension that increases the distance between the two fixing portions 40 and 41 of the cover 39 is generated. At this time, as shown in FIG. 5, the distance at the intermediate portion between the two slits 39 a and 39 a of the cover 39 made of a cloth that is harder to extend than the second base cloth 37 hardly changes from the initial L. At the positions of the two slits 39a and 39a, the slits 39a and 39a spread by ΔL due to the tension, so that the distance increases to L + ΔL larger than L. That is, the tension is maintained at the center portion of the cover 39 where the slits 39a and 39a do not exist, but the tension is weakened at both ends 39b and 39b of the cover 39 due to the widening of the slits 39a and 39a. 39b and 39b are lifted from the inner surface of the second base fabric 37, the vent hole 37b is opened (see FIG. 6), and excess gas is discharged from the vent hole 37b, so that the internal pressure of the airbag 32 is maintained at an appropriate level. . Further, once the both end edges 39b, 39b of the cover 39 are lifted from the inner surface of the second base cloth 37, the both end edges 39b, 39b of the cover 39 are pushed up by the gas that escapes from the vent hole 37b, and the vent hole 37b is further opened.

  As described above, since both ends of the cover 39 of the present embodiment are fixed to the second base fabric 37 by the fixing portions 40 and 41, when the airbag 32 is folded, the vent hole 37b provided in the second base fabric 37 is opened. On the other hand, it is possible to prevent the position of the cover 39 from shifting and to improve workability. Further, the cover 39 is formed in a trapezoidal shape, and the two slits 39a and 39a are formed on the fixed portion 41 side corresponding to the long bottom of the upper base and the lower base. It is possible to secure the maximum length of the slits 39a and 39a while minimizing it, and the vent hole 37b can be reliably opened when the airbag 32 is inflated.

  In addition to the first embodiment described above, various embodiments are conceivable regarding the shape of the cover 39, the number of slits 39a, and the positions of the slits 39a.

  In the second embodiment of FIG. 7A, three slits 39a are formed in series in a cover 39 radially inward of the vent hole 37b. In the third embodiment of FIG. 7B, one slit 39a, 39a is formed in the cover 39 on the radially inner side and the radially outer side than the vent hole 37b. In the fourth embodiment shown in FIG. 7C, the cover 39 has an elliptical shape, and one slit 39a is formed radially inward from the vent hole 37b. In the fifth embodiment of FIG. 7D, the cover 39 has a rhombus shape, and one slit 39a is formed on the radially inner side of the vent hole 37b.

  As described above, when the position and the number of the slits 39a are changed, the mode of deformation due to the elongation when the tension is applied to the cover 39 is different, but the cover 39 is partially expanded and deformed, and a part thereof is the second. By floating from the inner surface of the base fabric 37, the vent hole 37b can be opened in any embodiment.

  FIG. 8 shows a sixth embodiment of the present invention.

  This sixth embodiment is a modification of the first embodiment, and instead of extending the cover 39 to the position of the opening 37a of the second base fabric 37 and fixing it to the second base fabric 37 with a fixing portion 41 by sewing, A cover 39 is sandwiched between the flange 31a of the inflator 31 and the fixing ring 33 and fixed. According to the sixth embodiment, the fixing portion 41 by sewing becomes unnecessary, so that the number of processing steps can be reduced.

  FIG. 9 shows a seventh embodiment of the present invention.

  The seventh embodiment is also a modification of the first embodiment. In the first embodiment, two vent holes 37b and two covers 39 are provided at both ends in the radial direction of the second base fabric 37, respectively. It is provided one by one. The longitudinal direction of the covers 39, 39 is not in the radial direction but in the circumferential direction. According to the seventh embodiment, surplus gas can be discharged more reliably by providing a plurality of vent holes 37b, 37b.

  In the eighth embodiment of FIG. 10A, both ends of the two slits 39a, 39a are opened at the end edges 39b, 39b of the cover 39, and the end edges 39b, 39b of the cover 39 are formed by the slits 39a, 39a. Excess gas can be discharged so that 39b can float freely. In the ninth embodiment of FIG. 10 (b), notches 39c and 39c are formed at the edges 39b and 39b of the cover 39 so as to face both ends of the two slits 39a and 39a. When the tension of the cover 39 increases, the break starting from the notches 39c and 39c communicates with the slits 39a and 39a, and the same effect as that of the eighth embodiment of FIG. 10A can be achieved.

  Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.

  For example, the shape of the cover 39, the number of slits 39a, and the positions of the slits 39a are not limited to the embodiment, and can be changed as appropriate.

  In the embodiments, the airbag device for the driver's seat is illustrated, but the present invention is an airbag device for the passenger seat, an airbag device that deploys the airbag from the side of the seat at the time of a side collision, and a side edge of the roof at the time of a side collision. The present invention can be applied to any type of airbag device such as an airbag device that deploys a curtain-shaped airbag.

  Further, as a means for making the cover 39 harder to extend than the second base cloth 37, the direction of the fibers of the cover 39 and the direction of the fibers of the second base cloth 37 may be made different from each other, in addition to using cloths having different elongations.

Perspective view of the front part of the car compartment 2-2 line enlarged sectional view of FIG. Exploded perspective view of airbag Front view of airbag Explanatory drawing of the action when the airbag is inflated 6-6 sectional view of FIG. The figure corresponding to the said FIG. 5 which shows the 2nd-5th Example of this invention. The figure corresponding to the above-mentioned Drawing 5 showing the 6th example of the present invention. The figure corresponding to the above-mentioned Drawing 5 showing the 7th example of the present invention. The figure corresponding to the said FIG. 5 which shows 8th Example and 9th Example of this invention

Explanation of symbols

32 Airbag 37 Second base fabric (base fabric)
37b Vent hole 39 Cover 39a Slit 39b Edge 39c Notch 40 Fixed part 41 Fixed part

Claims (5)

A vent hole (37b) formed in the base fabric (37) of the airbag (32) that is inflated upon supply of gas in the event of a vehicle collision is covered with a cover (39) from the inner surface side of the base fabric (37). In the airbag device that opens the cover (39) in accordance with an increase in the internal pressure of the airbag (32),
The cover (39) is fixed to the base fabric (37) by two fixing portions (40, 41) positioned on both sides of the vent hole (37b), and at least one of the fixing portions (40, 41) and the vent hole. An air bag device having a slit (39a) extending in a direction substantially orthogonal to a straight line connecting the two fixing portions (40, 41) between (37b).   The airbag device according to claim 1, wherein a plurality of the slits (39a) are arranged in a direction substantially orthogonal to a straight line connecting the two fixing portions (40, 41).   The cover (39) is formed to have a width on one fixing part (40, 41) side wider than that on the other fixing part (40, 41) side, and the slit (39a) is formed on the one side of the cover (39). The airbag device according to claim 2, wherein the airbag device is formed only on the fixed portion (40, 41) side.   The airbag device according to any one of claims 1 to 3, wherein the slit (39a) is opened to an edge (39b) of the cover (39). The airbag device according to any one of claims 1 to 3, wherein a notch (39c) that faces an end of the slit (39a) is formed at an edge of the cover (39). .

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