JP2002012111A - Air bag for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the tether damage caused by increases in the gas temperature and gas quantity in an inflator in an air bag for vehicles wherein a tether 20 connects an occupant side cloth 12 and an inflator side cloth 14 for restraining them so that the distance between them does not increase more than a specified length in the air bag. SOLUTION: The tether 20 is formed by connecting the free ends of tether forming clothes 22 and 24 attached to their respective occupant side cloth 12 and an inflator side cloth 14. In this connection section 32 of the tether 20, a second sewn section 38 is provided on both sides of a first sewn section 34 on which both of the tether forming clothes 22 and 24 are overlapped and sewn to sew each cloth terminal on their respective other the tether forming clothes. In this case, the sewing pitch of the second sewn section 38 is set larger than that of the first sewn section 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag for a vehicle airbag device.

[0002]

2. Description of the Related Art An airbag device is a device for protecting an occupant by inflating an airbag at the time of a vehicle collision, and includes an inflator which is a gas generator and an airbag which is inflated by gas from the inflator. It is arranged in the steering wheel center of the vehicle, the instrument panel, and the like.

[0003] The airbag of such an airbag device is formed into a three-dimensionally inflatable bag shape in which an occupant-side cloth and an inflator-side cloth are joined at their peripheral edges. One or a plurality of tethers for connecting the occupant-side cloth and the inflator-side cloth are formed, and the tether restricts the space between the occupant-side cloth and the inflator-side cloth from expanding beyond a predetermined length when inflated. are doing.

FIG. 9 is a sectional view of a conventional airbag 100 having such a tether. This airbag 10
No. 0 is formed in a bag shape by sewing the peripheral edges of the occupant-side cloth 101 and the inflator-side cloth 102, and the inflator-side cloth 102 has a mounting hole 104 for mounting an inflator at the center thereof. Band-shaped tether forming cloths 105, 105 are sewn to the periphery of the mounting hole 104. A belt-like tether forming cloth 10 is also provided on the inner surface of the central portion of the occupant-side cloth 101 so as to face the mounting hole 104.
7, 107 are sewn. Then, the tether forming cloths 105, 105, 107, 107 facing each other are overlapped and sewn to each other to connect the occupant-side cloth 101 and the inflator-side cloth 102.
09 is formed.

[0005]

The above-described airbag 10
0, the tether 109 is pulled in the longitudinal direction when inflated by the gas generated by the inflator, and as shown in FIG.
Tension acts. When the gas temperature and the gas amount of the inflator rise, in the above structure, the tension acting on the joint 110 causes the surrounding tether forming cloth 10
There is a possibility that an eye misalignment occurs at 5,107. When such misalignment occurs, the high-temperature gas passes through the misalignment, and the sewing thread or the tether-forming cloth is exposed to the high-temperature gas, and the tether 109 may be damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to prevent damage to a tether due to an increase in gas temperature and gas amount of an inflator.

[0007]

According to a first aspect of the present invention, there is provided a vehicle airbag including an occupant-side cloth and an inflator-side cloth, wherein the occupant-side cloth and the inflator are disposed inside the bag. The side cloth is connected by a tether that regulates the distance between the two to be not more than a predetermined length, and the tether is formed of a tether forming cloth attached to the occupant side cloth and the inflator side cloth, respectively. Formed by joining the free ends, at the joint of this tether,
On both sides of the first sewn part where both tether forming cloths were sewn together,
A second sewing section is provided for sewing each cloth terminal to the other tether forming cloth, and a sewing pitch of the second sewing section is larger than a sewing pitch of the first sewing section.

In this first airbag, the sewing pitch of the second sewn portion is set larger than that of the first sewn portion. Therefore, when the airbag is inflated, even if tension acts on the connecting portion of the tether, The amount of misalignment in the second sewing portion is reduced. Then, when the misalignment occurs in the surrounding tether forming cloth in the first sewing portion, even if gas tries to enter the overlapping surface of both tether forming cloths from the misalignment portion,
Since the cloth ends of the superimposed tether forming cloths are stopped at the second sewing portion, gas does not escape outside through the superimposed surface. Therefore, heat damage due to gas from the inflator can be reduced, and damage to the tether can be prevented. Further, since the second sewing portion is merely added, the tether connection portion can be reinforced at low cost.

A second airbag for a vehicle according to the present invention is an airbag for a vehicle including an occupant-side cloth and an inflator-side cloth, wherein the occupant-side cloth and the inflator-side cloth are both inside the bag. Are connected by a tether that restricts the interval of the tether from spreading beyond a predetermined length, and the tether connects the free ends of the tether forming cloths respectively attached to the occupant-side cloth and the inflator-side cloth. At the joint portion of the tether, a protective cloth for protecting the joint portion is overlapped with both tether forming cloths, and these three members are sewn with a common sewing portion.

With this second airbag, when inflated,
Even if tension is applied to the joint of the tether and the misalignment occurs in the surrounding tether forming cloth, the misalignment is covered by the protective cloth, so that thermal damage due to gas from the inflator can be reduced. , Can prevent damage to the tether. Further, since only a protective cloth is added at the time of sewing the tether, the tether connection portion can be reinforced at low cost.

In this second airbag, the protective cloth may be biased such that a cloth direction is biased with respect to a longitudinal direction of the tether. In this case, when the tension acts on the tether joint, the protective cloth is pulled in the bias direction, so that the protective cloth acts as a cushioning material and can disperse the tension.

In the second airbag, the protective cloth and at least one tether forming cloth are sewn on both sides of a first sewn portion where the protective cloth and the two tether forming cloths are sewn together. A second sewing portion may be provided, and a sewing pitch of the second sewing portion may be larger than a sewing pitch of the first sewing portion. In this case, the second sewing portion having a larger sewing pitch than the first sewing portion has little misalignment. Even if the first sewing portion has misalignment, the cloth end of the protective cloth is stopped by the second sewing portion. Gas does not escape from the misalignment.

In the second airbag, at least one of the tether forming cloths is connected to the other tether forming cloth with its free end folded, and the folded back piece may constitute the protective cloth. .

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view of a vehicle airbag 10 according to a first embodiment of the present invention, and FIG. 2 is a sectional view of the airbag 10.

The airbag 10 is an airbag for a driver's seat, and includes an occupant-side cloth 12 for receiving an occupant and an inflator-side cloth 14 to which an inflator (not shown) is attached. Both the cloths 12 and 14 are circular, and are sewn 16 at the periphery thereof to form a bag shape that can be expanded into a three-dimensional shape. Inflator side cloth 1
A circular mounting hole 18 to which an inflator (not shown) is mounted is formed in the central portion of 4. The gas ejected from the inflator inflates the airbag 10 three-dimensionally as shown in FIGS.

Reference numeral 20 denotes a strap-shaped tether made of a flexible material such as a woven cloth.
And the inflator-side cloth 14 so as to regulate the distance between the cloths 12 and 14 so as not to be longer than the length of the tether. The two tethers 20 are arranged symmetrically around the mounting hole 20 on the diameter of the airbag 10. As a result, a uniform flat state as shown in the figure is maintained in a state where the airbag 10 is deployed and inflated.

The two tethers 20 are formed of a pair of first tether forming cloths 2 sewn to the occupant side cloth 12.
2 and a pair of band-shaped second tether forming cloths 24 sewn to the inflator-side cloth 14. First
The tether forming cloth 22 is provided at the center of the occupant side cloth 12 with the sewing portion 2.
6 and is arranged so as to extend diametrically outward from two opposing circular sewing portions 26.
The second tether forming cloth 24 is sewn to the peripheral edge of the mounting hole 18 by a circular sewing portion 30 for sewing a circular reinforcing cloth 28 to the peripheral edge of the mounting hole 18.
Are arranged so as to extend diametrically outward from two opposite locations. The pair of second tether forming cloths 24, 24
It is constituted by an integral cloth member connected to each other at a sewn fixed end.

Then, the first tether-forming cloth 22 and the second tether-forming cloth 24 facing the first tether-forming cloth 22 are sewn at intermediate connecting portions 32, 32 located substantially at the center of the tethers 20, 20 in the longitudinal direction. Tethers 20, 20 are formed. In detail, the intermediate joint portion 32 is formed by sewing the free end of the first tether forming cloth 22 with the free end of the second tether forming cloth 24, and the stitching is performed such that the free ends of each other are the other. The two 22 and 24 are overlapped so as to face the fixed end, and the overlapped portion is sewn with a first sewing portion 34 extending in the width direction of the tether 20.

On both sides of the first sewing portion 34 (on both sides in the longitudinal direction of the tether 20), tether forming cloths 22, 24 are provided.
A second sewn portion 38 is provided to sew each of the cloth ends to the other tether forming cloths 24 and 22. That is, as shown in FIGS. 2 and 3A, the second sewing on the occupant side for sewing the terminal of the second tether forming cloth 24 to the first tether forming cloth 22 is provided on the occupant side with respect to the first sewing portion 34. A portion 38a is provided, and the first sewing portion 34 is provided on the inflator side.
A second sewn portion 38b on the inflator side for suturing the end of the first tether forming cloth 22 to the second tether forming cloth 24 is provided.

The second sewn portion 38a on the occupant side and the second sewn portion 38b on the inflator side are sewn portions extending in the width direction of the tether 20, similarly to the first sewn portion 34. As shown in FIG. 1, the end portions of both the sewn portions 38 a and 38 b are connected by a sewn portion 38 c extending in the longitudinal direction of the tether 20, so that the second sewn portion 38 surrounds the first sewn portion 34. , And the sewn portions 34 and 38 of the intermediate connecting portion 32 are formed in the shape of a sun as a whole. By performing such sewing, the first sewing portion 34 and the second sewing portion 38 can be formed with one stroke.

The second sewing portion 38 is simply for fixing each cloth terminal to the tether 20.
The sewing pitch (sewing interval) of the sewing portion 38 is set to be larger than the sewing pitch of the first sewing portion 34. For example, when the sewing pitch of the first sewing portion 34 is 3 mm,
The sewing pitch of the sewing portion 38 is 4.5 mm. Thus, the second sewing portion 38 is formed to be easily stretched by loosely sewing. It is preferable that the sewing pitch of the second sewing portion 38 be 1.5 times or more the sewing pitch of the first sewing portion 34.

In the airbag 10, when the inflator is inflated by the gas generated by the inflator, when the tension is applied to the intermediate connecting portion 32 of the tether 20, the loosely sewn second sewing portion 38 reduces the amount of misalignment. FIG.
As shown in (b), the gap S around the first sewing portion 34
Occurs. As shown in FIG. 3C, this misaligned portion S
G is applied to the overlapping surface of both tether forming cloths 22 and 24
Try to penetrate, but the tether molding cloth 2
Since the cloth ends 2 and 24 are stopped by the second sewing portions 38a and 38b, the gas G does not escape outside through the overlapping surface. As described above, since the gas G does not escape from the misalignment portion S, thermal damage due to gas from the inflator can be reduced, and damage to the tether can be prevented. Further, since the second sewing portion 38 is simply added, the tether connecting portion 32 can be reinforced at low cost.

The second sewn portion 38 is formed of the first sewn portion 34.
May be formed only by the second sewn portion 38a on the occupant side and the second sewn portion 38b on the inflator side, instead of having a square shape surrounding the periphery. However, surrounding the first sewing portion 34 is advantageous in that the sewing operation efficiency is high and that gas is prevented from being released.

FIG. 4 is a partially cutaway perspective view of a vehicle airbag 40 according to a second embodiment of the present invention, and FIG. 5 is a sectional view of the airbag 40. This second embodiment differs from the first embodiment in the configuration of the intermediate coupling portion 32 of the tether 20. Hereinafter, only different points will be described.

In the airbag 40 of the second embodiment, a patch-like protective cloth 36 is added at the intermediate connecting portion 32 of the tether 20 to protect the connecting portion 32 from gas generated by the inflator. This protective cloth 36 is a rectangular cloth piece having a width dimension substantially the same as the width dimension of the tether 20, and a longitudinal dimension extending on both sides beyond the overlapped portion of the tether forming cloths 22, 24. It is formed so that.

The protective cloth 36 is arranged such that the cloth direction is biased with respect to the longitudinal direction of the tether 20. In detail, as shown in FIG. 6B, the first tether forming cloth 22 is provided with the cloth direction x1, that is, the direction of the warp or the weft, parallel to the longitudinal direction X of the tether 20. . Similarly, the cloth direction x2 of the second tether forming cloth 24 is provided in parallel with the longitudinal direction X of the tether 20. On the other hand, the protective cloth 36 is provided such that the cloth direction x3 is inclined at an angle of about 45 ° with respect to the longitudinal direction X of the tether 20.

As shown in FIGS. 4 and 5, the protective cloth 36 covers the intermediate connecting portion 32 of the tether 20 from the radial inside of the airbag 10, that is, the center side of the airbag provided with the mounting hole 18. So as to face the first and second tether forming cloths 22 and 24. Then, the protective cloth 36
Are sewn to the intermediate connecting portion 32 by a first sewing portion 34 that connects the first tether forming cloth 22 and the second tether forming cloth 24.

The first and second tether forming cloths 22, 24 and the protective cloth 36 are overlapped and the three parts are sewn together and sewn together (on both sides in the longitudinal direction of the tether 20).
Is provided with a second sewing portion 38 in which the protective cloth 36 and one of the tether forming cloths are overlapped and sewn. That is, the first
On the occupant side with respect to the sewn portion 34, there is provided a second sewn portion 38a on the occupant side for suturing the overlapped portion of the protective cloth 36 and the first tether forming cloth 22, and on the inflator side with respect to the first sewn portion 34. Is the protective cloth 36 and the second tether forming cloth 24
And a second sewing portion 38b on the inflator side for suturing the overlapped portion with. These 38a, 38b are:
It is merely provided to fix the protection cloth 36 to the tether 20, and therefore, the first tether forming cloth 22 and the second tether forming cloth 24 are not stitched at the sewn portions 38a, 38b.

The second sewn portion 38a on the occupant side and the second sewn portion 38b on the inflator side are sewn portions extending in the width direction of the tether 20, similarly to the first sewn portion 34. FIG.
As shown in (b), the ends of both the sewn portions 38a and 38b are connected by a sewn portion 38c extending in the longitudinal direction of the tether 20, whereby the second sewn portion 38 is connected to the first sewn portion 34. It is formed in a square shape surrounding the periphery.
The sewing pitch of the second sewing portion 38 is set to be larger than the sewing pitch of the first sewing portion 34 as in the first embodiment.

In the airbag 40, when the tension is applied to the intermediate joint portion 32 of the tether 20 when the airbag 40 is inflated, the protective cloth 36 is pulled in the bias direction, so that the protective cloth 36 acts as a cushioning material and disperses the tension. it can.
Further, in this embodiment, the second sewn portion 38 merely sews the protective cloth 36 to the tether-forming cloths 22 and 24 and is sewn more loosely than the first sewn portion 34. The tension can be dispersed also in the second sewing portion 38. As described above, the misalignment of the cloth pieces around the first sewing portion 34 can be reduced.

Further, in the airbag 40, even if a gap occurs around the first sewing portion 34, the gap portion is covered with the protective cloth 36. Further, since the cloth end of the protective cloth 36 is stopped by the second sewing portion 38, gas does not escape from the misalignment portion as in the first embodiment. Therefore,
Thermal damage due to gas from the inflator can be reduced.

As described above, with the airbag 40,
Damage to the tether 20 can be effectively prevented. Moreover, since only the protective cloth 36 is added when the tether 20 is sewn, reinforcement can be performed at low cost.

In the above embodiment, the second sewn portion 38 for fixing the protective cloth 36 to the tether 20 is provided. However, even when the second sewn part 38 is not provided, the misalignment portion is covered by the protective cloth 36. Thus, the connecting portion 32 of the tether 20 can be protected.

The protective cloth 36 may be sewn together with the tether forming cloths 22 and 24 at the second sewing portion 38. However,
As described above, if the protection cloth 36 and the two tether forming cloths 22 and 24 are sewn in the second sewing portion 38 as well, the elongation is reduced and it becomes difficult to absorb the tension. In the second sewn portions 38 on both sides of the first sewn portion 34, it is preferable to sew only the protective cloth and one tether forming cloth.

In the second embodiment, the protective cloth 36
Are superimposed on the first and second tether forming cloths 22 and 24 so as to face the center of the airbag. However, the present invention is not limited to this.
May be overlapped so as to face outward in the radial direction, or may be arranged so as to be sandwiched between the first and second tether forming cloths 22 and 24. However, it is more effective to arrange the airbag toward the center of the airbag where the gas from the inflator is easily blown.

FIG. 7 is a view showing an intermediate connecting portion 32 of the tether 20 in the airbag according to the third embodiment of the present invention. In this embodiment, the intermediate coupling portion 3 of the tether 20
The configuration of the protection cloth 36 for protecting the second embodiment is different from that of the second embodiment. Hereinafter, only different points will be described.

As shown in FIG. 7A, in this embodiment, the free end of the second tether forming cloth 24 is folded and sewn to the first tether forming cloth 22 in this folded state. The protection cloth 36 is formed by the folded pieces. More specifically, the tip of the second tether forming cloth 24 laid on the inside of the first tether forming cloth 22 is folded back, and the folded pieces are laid on the inside of the second tether forming cloth 24, and these first and second tethers are formed. Three parts, the forming cloths 22 and 24 and the protection cloth 36 which is a folded piece, are sewn by the first sewing part 34. The folded piece is sewn to the second tether forming cloth 24 by the second sewing portion 38 at the tip end. As shown in FIG. 7B, the second sewn portion 38 constitutes a square-shaped sewn portion together with the first sewn portion 34.

Also in the airbag of this embodiment, when a gap occurs around the first sewing portion 34, the protective cloth 3
Since the misalignment portion is covered by 6, the thermal damage due to gas from the inflator can be reduced, and the tether 20 can be prevented from being damaged. In addition, when the tether 20 is sewn, one of the tether forming cloths 24 can be turned back into the protective cloth 36, so that the reinforcing can be performed at low cost. In addition, the protective cloth 3 made of this folded piece
6 may be configured separately from the second tether forming cloth 24 by being separated by the folding line 50.

FIG. 8 is a view showing a modification of the embodiment shown in FIG. 7. In this example, the first tether forming cloth 22 and the second
The free ends are folded back on both of the tether forming cloths 24,
In this folded state, they are sewn together. For this reason, in this example, protective cloths 36, 36 made of folded pieces are provided on both the inner and outer sides of the tether 20.

In this case, similarly to the third embodiment, when the misalignment occurs around the first sewing portion 34, the protective cloth 3
Since the misalignment portion is covered by 6, the thermal damage due to gas from the inflator can be reduced. In this case as well, the protective cloth 36 made of a folded piece is
Each tether-forming cloth 2 is separated by a folding line 50.
It may be configured separately from 2, 24.

The present invention is not limited to the driver airbag described above, but is applicable to a passenger airbag or a vehicle airbag provided at another location. The shape is not limited to the circular shape described above.

[0043]

According to the first airbag for a vehicle of the present invention, when inflated, tension acts on the connecting portion of the tether, and even if the tether forming cloth around the first sewing portion is misaligned. ,
Since the cloth end of the tether forming cloth is stopped at the second sewing portion, gas does not escape from the misalignment portion to the outside through the overlapping surfaces of both tether forming cloths. Since gas does not escape from the misaligned portion, thermal damage due to gas from the inflator can be reduced, and damage to the tether can be prevented. Also, since only the second sewing part is added,
The tether joint can be reinforced at low cost.

In the second airbag for a vehicle according to the present invention, when inflated, tension acts on the connecting portion of the tether, and even if the tether forming cloth around the tether is misaligned, the tread is formed by the protective cloth. Since the portion is covered, thermal damage due to gas from the inflator can be reduced, and damage to the tether can be prevented. Further, since only a protective cloth is added at the time of sewing the tether, the tether connection portion can be reinforced at low cost.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a vehicle airbag according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the airbag.

FIG. 3A is a cross-sectional view of an intermediate coupling portion of a tether in the airbag, and FIGS. 3B and 3C are cross-sectional views showing a state where tension acts on the intermediate coupling portion.

FIG. 4 is a partially cutaway perspective view of a vehicle airbag according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of the airbag.

FIG. 6A is a cross-sectional view of an intermediate coupling portion of a tether,
(B) is a plan view thereof.

FIG. 7A is a cross-sectional view of an intermediate coupling portion of a tether according to a third embodiment, and FIG. 7B is a plan view thereof.

FIG. 8A is a cross-sectional view of an intermediate coupling portion of a tether according to a modification of the third embodiment, and FIG. 8B is a plan view thereof.

FIG. 9 is a sectional view of a conventional airbag.

FIG. 10A is a cross-sectional view of an intermediate joint portion of a tether in a conventional airbag, and FIG. 10B is a plan view thereof.

[Explanation of symbols]

 10, 40 ... airbag 12 ... occupant side cloth 14 ... inflator side cloth 20 ... tether 22 ... first tether forming cloth 24 ... second tether forming cloth 32 ... intermediate coupling part 34 ... first Sewing part 36 Protective cloth 38 Second sewing part

Claims (5)

[Claims] 1. An airbag for a vehicle including an occupant-side cloth and an inflator-side cloth, wherein a space between the occupant-side cloth and the inflator-side cloth does not extend beyond a predetermined length inside the bag. The tether is formed by joining free ends of tether forming cloths respectively attached to the occupant-side cloth and the inflator-side cloth. On both sides of a first sewn portion where both tether forming fabrics are overlapped and sewn, a second sewn portion for sewing each fabric end to the other tether forming fabric is provided, and the sewing pitch of the second sewn portion is set to the first pitch. An airbag for a vehicle, wherein the airbag is larger than a sewing pitch of a sewing portion. 2. An airbag for a vehicle including an occupant-side cloth and an inflator-side cloth, wherein a space between the occupant-side cloth and the inflator-side cloth does not extend beyond a predetermined length inside the bag. The tether is formed by joining free ends of tether forming cloths respectively attached to the occupant-side cloth and the inflator-side cloth. An airbag for a vehicle, wherein a protective cloth for protecting the connecting portion is overlapped with both tether forming cloths, and the three members are sewn at a common sewing portion. 3. The airbag for a vehicle according to claim 2, wherein the protective cloth is arranged such that a cloth direction is biased with respect to a longitudinal direction of the tether. 4. A second sewn section in which the protective cloth and at least one tether forming cloth are sewn on both sides of a first sewn section in which the protective cloth and the two tether forming cloths are sewn together. The vehicle airbag according to claim 2 or 3, wherein a sewing pitch of the second sewing portion is larger than a sewing pitch of the first sewing portion. 5. The at least one tether forming cloth is coupled to the other tether forming cloth with its free end folded back, and the folded piece constitutes the protective cloth. The airbag for a vehicle as described in the above.