JP5201106B2 - Airbag device - Google Patents

Description

  The present invention relates to an airbag device, and more particularly to an airbag device in which a part of a sewing part is a double stitch sewing part.

Patent Document 1 discloses an airbag for a passenger seat that is folded and stored on the lower side of an instrument upper panel of a vehicle and deploys at the time of a vehicle collision.
As shown in FIGS. 14 to 17, the conventional airbag 1 includes a first type sewing portion 4-1 that is bent and extended from the outer surface of the airbag (the base fabric 2, the sewing portion between the two, FIG. 15, or 17), a second type sewing portion 4-2 extending in the same direction as the outer surface of the airbag (the reinforcing patch 3 and the base shown in FIG. 16). The entire sewing portion 4 including the sewing portion with the cloth 2 is composed of a single stitch sewing portion (sewing portion having one row of stitches) 4s. The sewing pitch ps of the conventional single stitch sewing portion 4s is, for example, 2.5 mm for both the first type sewing portion 4-1 and the second type sewing portion 4-2.
In recent years, the use of omni bags has increased from the viewpoint of safety, and as a result, the number of sewing sites has increased and the number of burstable sites has increased.

  In the conventional airbag, at the initial stage of airbag deployment corresponding to the time when the pressure of the inflation gas from the inflator is high, from the sewing portion in the vehicle front side region, for example, the sewing portions 4-1 and 4-2 in FIG. There is a risk of tearing (“breaking” is also referred to as “burst”). This tearing is the tearing of the air bag due to the cut of the base fabric that occurs so that the perforation contacts. Conventionally, confirmation and evaluation have been carried out by taking measures by adding or expanding the reinforcing patch 3 and changing the folding method of the airbag 1 (hereinafter simply referred to as “folding change”).

JP 2007-45190 A

However, the above-described countermeasures against air bag breakage have the following problems.
First, if measures are taken by adding or enlarging a reinforcing patch, there is a risk of causing a secondary failure in airbag deployment. For example, the increase in the mass of the reinforcing patch may cause a windshield crack when the airbag is deployed.
Further, if measures are taken by changing the folding of the airbag, the airbag deployment behavior changes due to the folding change of the airbag. Therefore, it is necessary to redo the evaluation test in the actual vehicle.

  The object of the present invention is to increase the load resistance value and / or energy absorption of an airbag without adding or expanding a reinforcing patch (compared to the conventional one) or changing the airbag folding, and at the time of airbag deployment. It is an object of the present invention to provide an airbag device capable of preventing the airbag from being torn.

The airbag apparatus of the present invention that solves the above problems or achieves the above object is as follows.
(1) An airbag apparatus according to the present invention is an airbag apparatus provided with an airbag that is manufactured by sewing only a plurality of pieces of cloth constituting a pressure-resistant portion at a sewing portion and that is supplied with an inflation gas and deployed when a vehicle collides. In the airbag device, a part of the sewing portion is a double-stitch sewing portion having two rows of seams formed at a sewing interval.
A second type of sewing portion having a first stitched portion formed by a portion where the double stitch sewing portion is bent and extended from the outer surface of the airbag, and a second portion formed by a portion extending in the same direction as the outer surface of the airbag. At least one of the sewing parts.
One where the stitching pitch of the two stitches of the double stitch sewing part is different from each other, and the sewing pitch of the absorption stitch, which is the stitch that is initially tensioned when the airbag is deployed, is not initially tensioned when the airbag is deployed The sewing pitch is larger than the sewing pitch of the main stitch which is the seam.

(2) In the airbag device of (1), the plurality of cloth pieces constituting the pressure-resistant portion include at least one of a base fabric and a reinforcing patch, and at the sewing portion, at least one of the base fabric and the reinforcing patch is sewn. The

(3) In the airbag device according to (1) or (2) , the first type sewing portion includes a sewing portion that sews the base fabrics, and the second type sewing portion includes the reinforcing patch and the base fabric. It consists of a sewing part for sewing.

(4) In the airbag device according to any one of the above (1) to (3), the sewing portion other than the double stitch sewing portion is composed of a single stitch sewing portion, and the sewing pitch of the main stitch of the double stitch sewing portion is single. It is equal to or substantially equal to the sewing pitch of the seam of the stitch sewing portion.

(5) above (1) - (4) In any one of the airbag apparatus, the airbag, passenger airbag housed folded below the instrument upper panel of the vehicle prior to deployment Consists of
The airbag has a first deployment part that pushes open the instrument upper panel during deployment and deploys upward and rearward, and a second deployment part that deploys rearward, up, down, left and right with respect to the first deployment part. And is folded so as to be developed in the order of the first development part and the second development part.

(6) In the airbag device according to (5), the double stitch sewing portion is located on the front surface of the first deployment portion in a state where the first deployment portion is deployed, and a central sewing portion extending in the vertical direction at the center in the left-right direction; And a left and right sewing part extending in the vertical direction at a position spaced from the central sewing part to the left and right, the central sewing part is composed of a first type sewing part, and the left and right sewing part is a second type sewing part. The first type sewing part is composed of a sewing part between base fabrics or a sewing part of two base cloths and two reinforcing patches, and the second type sewing part is a reinforcing patch and a base cloth. It consists of a sewing part.

According to the airbag device of the above (1), since a part of the sewing part where only the plurality of cloth pieces constituting the pressure-resistant part are sewn is the double stitch sewing part, the tension applied to the sewing part when the airbag is deployed Can be received at the seam (absorption seam) that is first tensioned when the airbag is deployed, and the load on the seam (main seam) that is not initially tensioned when the airbag is deployed can be reduced. Compared to the sewing portion, the load resistance value and energy absorption amount of the airbag at the time of deployment can be increased, and the airbag can be prevented from being torn at the time of deployment.
In this case, simply changing the sewing from a single stitch to a double stitch can increase the load capacity and energy absorption of the airbag, so adding or expanding airbag reinforcement patches or changing the folding of the airbag Is not accompanied.
In addition, even if a thread breakage occurs at the seam that is initially tensioned when the airbag is deployed in the double stitch, if the seam that is not initially tensioned when the airbag is deployed remains, the airbag deployment performance will be improved. Since there is no influence, it is not necessary to repeat the evaluation test as long as the seam that is initially tensioned when the airbag is deployed can maintain the conventional strength.
Moreover, since the double stitch sewing part includes at least one of the first type sewing part and the second type sewing part, the first type sewing part of the present invention and the second type sewing part are provided. By applying the sewing portion to the sewing portion shown in FIGS. 15 and 16 having the conventional structure shown in FIG. 14, it is possible to prevent the airbag from being torn in the sewing portion shown in FIGS. 15 and 16 having the conventional structure shown in FIG. 14. Or can be suppressed.
In addition, since the sewing pitch of the absorption sewing is made larger than the sewing pitch of the main sewing, damage to the bag base fabric at the absorption sewing site can be reduced, and the type of base fabric breakage that occurs to connect the sewing machine hole at the absorption sewing site The airbag can be prevented from being suppressed or suppressed.

According to the airbag device of the above (2), since the tether is not a cloth piece constituting the pressure-resistant portion of the airbag, only a plurality of cloth pieces constituting the pressure-resistant portion are sewn in the sewing portion where the tether is sewn. Not included in the sewing part.

According to the airbag device of the above (3), the first type sewing portion is used as a sewing portion for sewing the base fabrics together, and the second type sewing portion is a sewing for sewing the reinforcing patch and the base fabric. Used for parts.

  According to the airbag device of (4) above, since the sewing pitch of the main stitch of the double stitch sewing portion is equal to or substantially equal to the sewing pitch of the seam of the single stitch sewing portion, the load resistance value of the double stitch sewing portion is As a minimum, it is possible to secure the load resistance value of the single stitch sewing portion other than the double stitch sewing portion.

  According to the airbag device of (5) above, the airbag has the first deployment portion and the second deployment portion, and is deployed in the order of the first deployment portion and the second deployment portion. By associating the initial high pressure time of the expansion gas from the first expansion portion with the expansion timing of the first expansion portion, it is possible to provide the double stitch sewing portion only in the first expansion portion where the high pressure is applied. . Thereby, compared with the case where all the sewing parts of an airbag are made into a double stitch, the increase in manufacturing cost can be suppressed.

  According to the airbag device of (6) above, the center stitching portion that extends in the vertical direction at the center in the left-right direction, the double stitch sewing portion is located on the front surface of the first deployment portion in a state where the first deployment portion is deployed, Left and right sewing parts extending in the vertical direction at positions separated from the central sewing part, the central sewing part is composed of a first type sewing part, and the left and right sewing parts are composed of a second type sewing part. Therefore, the airbag breakage that may have occurred in the first type sewing portion 4-1 and the second type sewing portion 4-2 of the conventional airbag 1 shown in FIG. It is possible to prevent or suppress only by double stitching only the center sewing part and the left and right sewing parts on the front surface of the part.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of an airbag of an airbag device according to an embodiment of the present invention as viewed from the front of a vehicle after deployment toward the rear. It is a partially expanded sectional view which follows the AA line of the airbag of FIG. It is a partially expanded sectional view which follows the BB line of the airbag of FIG. It is an example (example of a double stitch) of the partially expanded sectional view which follows the CC line of the airbag of FIG. It is another example (example of a single stitch) of the partially expanded sectional view which follows the CC line of the airbag of FIG. It is a partially expanded sectional view which follows the DD line of the airbag of FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged cross-sectional view of an airbag device according to an embodiment of the present invention, as viewed from the side of a vehicle, in the initial stage of an airbag and its vicinity. It is the perspective view which looked at the airbag of the airbag apparatus of the Example of this invention from diagonally forward of the vehicle after airbag deployment toward diagonally backward. FIG. 9 is a cross-sectional view of the airbag of FIG. 8 in a folded state. In the tensile test using the strip of the airbag of the airbag device of the present invention, a sewing simulation specification (i) of the first type of sewing portion comprising a sewing portion of base fabrics that are bent and extended from the outer surface of the airbag. and (vi) and a sewing simulation specification (vii) to (xii) of a second type sewing part comprising a sewing part of a reinforcing patch and a base fabric extending in the same direction as the outer surface of the airbag. is there. Table showing the maximum breaking load of the sewing simulation specifications (i) to (vi) of the first type sewing portion in the airbag tensile test of the airbag apparatus of the present invention, and the load vs. air of some specifications It is a graph which shows a bag expansion | deployment stroke. The table showing the maximum breaking load of the sewing type specifications (vii) to (xii) of the second type sewing part in the tensile test of the airbag of the airbag device of the present invention, and the load vs. air of some specifications It is a graph which shows a bag expansion | deployment stroke. It is a graph which shows the tendency of the pressure of the inflation gas of an inflator versus time. It is the front view (figure corresponding to Drawing 1 of the present invention) of the conventional air bag (the sewing part consists only of a single stitch sewing part) seeing from the vehicles front after deployment to the back. FIG. 15 is a partially enlarged cross-sectional view (a diagram corresponding to FIG. 2 of the present invention) along the line EE of the airbag of FIG. 14. FIG. 15 is a partially enlarged cross-sectional view (a diagram corresponding to FIG. 3 of the present invention) taken along line FF of the airbag of FIG. 14. FIG. 15 is a partially enlarged cross-sectional view (a diagram corresponding to FIGS. 4 and 5 of the present invention) along the line GG of the airbag of FIG. 14.

Below, the airbag apparatus which concerns on this invention is demonstrated with reference to FIGS. 1 to 9 show an embodiment of the present invention, and FIGS. 10 to 12 show test specifications and test results applicable to the embodiment of the present invention.
In the figure, “UP” indicates the upper side in the vehicle vertical direction, and “OUT” indicates the vehicle left-right direction (vehicle width direction) outside.

  As shown in FIGS. 1 to 9, the airbag device 10 of the present invention is manufactured by sewing a plurality of cloth pieces constituting a pressure-resistant portion at a sewing portion and is supplied with an inflation gas and deployed when a vehicle crashes. A bag 11 is provided.

  The airbag 11 is produced by sewing a plurality of pieces of cloth at the sewing portion 14. The plurality of cloth pieces include the base cloth 12 and / or the reinforcing patch 13. Since the tether does not constitute the pressure-resistant portion of the airbag, it is not included in the plurality of cloth pieces. In a region where only the base fabric 12 is provided, the pressure-resistant portion of the airbag 11 is a single-sheet configuration of the base fabric 12. The reinforcing patch 13 is provided on the outer surface side of the base fabric 12, and the pressure-resistant portion of the airbag 11 has a two-sheet configuration of the base fabric 12 and the reinforcing patch 13 at a portion where the reinforcing patch 13 is provided.

  A part of the sewing portion 14 has two rows of stitches 14a and 14b (14a is a main stitch and 14b is an absorption stitch added to the main stitch 14a) formed at a sewing interval d. The double stitch sewing portion 14d shown in FIG. 4 is used. Of the sewn part 14, the part other than the double stitch sewn part 14d is a single stitch sewn part 14s shown in FIG. 5 or 6 having one row of seams 14a (main stitching).

  The double stitch sewing portion 14d is a first type sewing portion (sewing portion between the base fabrics in FIG. 2) that includes a sewing portion that sews the base fabrics 12 and 12 that are bent and extended from the outer surface of the airbag to the inside of the airbag. Or a sewing portion for sewing the reinforcing patch 13 and the base fabric 12 extending in the same direction as the outer surface of the airbag. 2 types of sewing parts (sewing part of the reinforcing patch and the base fabric in FIG. 3) 14-2 are included.

In any double stitch sewing portion 14d of the first type sewing portion 14-1 and the second type sewing portion 14-2, the sewing pitch pa of the two rows of stitches 14a, 14b of the double stitch sewing portion 14d. , Pb are different from each other. In that case, the sewing pitch pb of the absorption stitch 14b, which is the first seam to which tension is applied when the airbag is deployed, is set larger than the sewing pitch pa of the main stitch 14a, which is the first stitch to which tension is not applied when the airbag is deployed. It is.
The double stitch sewing portion 14d corresponds to a single stitch 14s (single stitch conforming to the conventional single stitch 4s) added with an absorption stitch 14b having a sewing pitch larger than the single stitch 14s at an interval d.

  The sewing pitch pa of the main stitch 14a of the double stitch sewing portion 14d is equal to or substantially equal to the sewing pitch ps of the seam of the single stitch sewing portion 14s. The sewing pitch ps of the seam of the single stitch sewing portion 14s is equal to or substantially equal to the sewing pitch ps of the conventional single stitch sewing portion 4s.

  Of the two stitches 14a, 14b of the double stitch sewing portion 14d, the sewing pitch pa of the main stitch 14a is desirably set to 2.5 mm. The sewing pitch pa of the main stitch 14a is equal to or substantially equal to the sewing pitch ps (2.5 mm) of the conventional single stitch sewing portion.

  Of the two rows of stitches 14a and 14b of the double stitch sewing portion 14d, the sewing pitch pb of the absorption stitch 14b is desirably set to 4.5 mm.

  When the double stitch sewing portion 14d is composed of the first type sewing portion 14-1, the sewing interval d between the two stitches 14a, 14b of the double stitch sewing portion 14d is desirably set to 5.0 mm. .

  When the double stitch sewing portion 14d is composed of the second type sewing portion 14-2, the sewing interval between the two stitches 14a and 14b of the double stitch sewing portion 14d is preferably 5.0 mm ± 2.5 mm to 10 mm. It is set in a range of ± 2.5 mm, that is, 2.5 mm to 12.5 mm.

  The reason why the sewing pitches pa and pb and the sewing interval d of the main sewing 14a and the absorption sewing 14b of the double stitch sewing portion 14d are set as described above was performed using strips shown in FIGS. This will be described based on the tensile test results of the simulated specifications (1) to (xii) of the product of the present invention.

FIG. 10 shows a simulation specification used in the test. Specifications (i) to (vi) show simulated specifications of the first type sewing unit 14-1, and specifications (vii) to (xii) show simulated specifications of the second type sewing unit 14-2 ( Hereinafter, it is also simply referred to as “specification”.
Of the specifications (i) to (vi), (i) to (iii) indicate a single stitch sewing portion 14s (same as the simulation specification of the conventional single stitch sewing portion 4s), and (iv) to (vi) Indicates a simulation specification of the double stitch sewing portion 14d.

  As shown in FIG. 10, specifications (i), (ii), and (iii) are cases where the sewing pitch ps is 2.5 mm, 4.5 mm, and 3.5 mm, respectively. The specification (iv) is a case where the sewing pitch pa of the main sewing 14a is 2.5 mm, the sewing pitch pb of the absorption sewing 14b is 4.5 mm, and the distance d between the main sewing 14a and the absorption sewing 14b is 5 mm. The specification (v) is a case where the sewing pitch pa of the main sewing 14a is 2.5 mm, the sewing pitch pb of the absorption sewing 14b is 2.5 mm, and the distance d between the main sewing 14a and the absorption sewing 14b is 5 mm. The specification (vi) is a case where the sewing pitch pa of the main sewing 14a is 2.5 mm, the sewing pitch pb of the absorption sewing 14b is 4.5 mm, and the distance d between the main sewing 14a and the absorption sewing 14b is 10 mm.

  Of specifications (vii) to (xii), specifications (vii), (viii), (x), and (xi) are simulated single-stitch specifications, while specifications (ix) and (xii) are double-stitched specifications. It is a simulated specification. Specifications (vii), (x), and (xi) are when the sewing pitch pa of the main stitch 14a is 2.5 mm, and specifications (viii) are when the sewing pitch pa is 4.5 mm. The specification (ix) is the case where the sewing pitch pa of the main sewing 14a is 2.5 mm, the sewing pitch pb of the absorption sewing 14b is 4.5 mm, and the distance d between the main sewing 14a and the absorption sewing 14b is 5 mm. The specification (xii) is a case where the sewing pitch pa of the main sewing 14a is 2.5 mm, the sewing pitch pb of the absorption sewing 14b is 4.5 mm, and the distance d between the main sewing 14a and the absorption sewing 14b is 10 mm.

  FIG. 11 shows the tensile test results of the simulation specifications (i) to (vi) of the first type sewing part 14-1. The test results show the maximum breaking load of each specification (i) to (vi) in a table, and the load vs. stroke of a representative example among the specifications (i) to (vi) is shown in a graph. Tests were performed twice for each of the simulated specifications (i) to (vi). The table shows the maximum breaking load at each time and the average value AVE in each specification. The breaks in each of the specifications (i) to (vi) were thread breaks.

  FIG. 12 shows the tensile test results of simulated specifications (vii) to (xii) of the second type sewing part 14-2. The test results show the maximum breaking load of each specification (vii) to (xii) in a table, and the load versus stroke of a representative example among the specifications (vii) to (xii) is shown in a graph. Tests were performed twice with each specification of simulated specifications (vii) to (xii). The table shows the maximum breaking load at each time and the average value AVE in each specification. The breaks in the specifications (vii) to (xii) were all out of the base fabric.

  In FIG. 11 (the test result of the first type sewing part 14-1), the test results of the specifications (i) to (iii) indicate that the load resistance is higher when the sewing pitch ps is narrower in the single stitch. ing. However, if the width is less than 2.5 mm, there is a risk of the base fabric being cut (base fabric being cut by connecting the perforated holes). Therefore, the sewing pitch ps of the single stitch sewing portion 14s and the double stitch sewing portion 14d The sewing pitch pa of the main stitch 14a is the same as the sewing pitch 2.5 mm used in the conventional single stitch sewing portion 4s.

  The fact that the airbag is not allowed to be torn by cutting the base fabric is the same in the second type sewing unit 14-2. Therefore, the sewing of the single stitch sewing unit 14s is also performed for the second type sewing unit 14-2. The pitch ps and the sewing pitch pa of the main stitch 14a of the double stitch sewing portion 14d are the same as the sewing pitch 2.5 mm used in the conventional single stitch sewing portion 4s.

In FIG. 11, specification (v) has a much higher load-bearing value than specification (i), but there is a risk of the base fabric being cut off at the absorption stitch 14b part of specification (v). .
Further, in FIG. 11, the specification (iv) is the time after the time when the thread breakage occurs in the absorption sewing 14b (the time when the stroke is about 60 mm and the load is suddenly reduced in the curve of the specification (iv)). The maximum breaking load of the sewing 14a is higher than the specification (i), and it is shown that the load on the main sewing 14a is reduced by providing the absorption sewing 14b. In addition, since the absorbed energy amount (the area below the curve) of the specification (iv) is larger than the absorbed energy amount of the specification (i), adding the absorbent seam 14b has an effect of suppressing the breakage of the airbag. It is shown that.

  From this, the sewing pitch pb of the absorption stitch 14b is made larger than the sewing pitch pa of the main stitch 14a, and the sewing pitch pb of the absorption stitch 14b is set to 4.5 mm, for example.

  In FIG. 11, the test results of the specifications (iv) and (vi) indicate that the load resistance is higher when the sewing interval d between the two stitches 14a and 14b of the double stitch sewing portion 14d is narrower. . Accordingly, when the double stitch sewing portion 14d is composed of the first type sewing portion 14-1, the sewing interval d between the seams 14a and 14b of the double stitch sewing portion 14d is set to 5.0 mm.

  FIG. 12 shows the results of the test of the second type sewing unit 14-2. The single stitch simulation specifications (vii), (viii), (x), (xi) and the double stitch simulation specifications (ix), (xii) In both cases, the breaking load is larger than the breaking load of the first type sewing portion 14-1 in FIG. 11. As a result, the same sewing pitch as the absorption stitch 14b and the main sewing 14a of the first type sewing portion 14-1 may be used for the absorption stitch 14b and the main sewing 14a of the second type sewing portion 14-2. It can be seen that no problem arises in terms of load resistance.

  In the case of the second type sewing portion 14-2, FIG. 12 shows that the sewing interval d between the main sewing 14a and the absorption sewing 14b is 5 mm based on the comparison of the double stitch simulation specifications (ix) and (xii). The maximum breaking load value shows that the amount of energy absorption hardly changes even when the value is changed between 1 and 10 mm. From this, when the double stitch sewing portion 14d is composed of the second type sewing portion 14-2, the sewing interval between the two stitches 14a, 14b of the double stitch sewing portion 14d is set to 10 mm.

  As shown in FIGS. 1, 7, 8, and 9, the airbag 11 includes a first deployment portion 11 a that pushes open the instrument upper panel 15 during deployment and deploys upward and rearward along the windshield 19. The second unfolding portion 11b is unfolded rearward and left and right, and is folded so as to unfold in the order of the first unfolding portion 11a and the second unfolding portion 11b.

  The airbag 11 is, for example, a passenger seat airbag, and is folded under the instrument upper panel 15 of the vehicle before deployment as shown in FIG. The case 20 is housed. The first deployment portion 11a of the airbag 1 is expanded by receiving supply of inflation gas from the inflator 21 at the time of a vehicle collision, and connects the door portion of the airbag door 16, the instrument upper panel 15 and the skin 18 with an integral flange. It pushes open around 17 and expands and expands below and behind the windshield and above and behind. The second deployment part 11b of the airbag 11 is further deployed and inflated in the vehicle rearward and left-right direction. The inflated airbag 11 restrains the occupant's shoulder, chest, abdomen, and waist from the front.

  As shown in FIG. 13, the expansion gas from the inflator 21 rises rapidly immediately after operation (about 7 msec) to become a peak, and then has a characteristic of dropping from the peak. The deployment and inflation timing of the first deployment portion 11a of the airbag 11 corresponds to the initial high pressure holding timing T1 of the inflation gas from the inflator 21, and the deployment and inflation timing of the second deployment portion 11b of the airbag 11 are: This corresponds to the decompression time T2 of the expansion gas from the inflator 21. Therefore, the front surface in the vehicle front-rear direction of the first deployment portion 11a of the airbag 11 is a portion that receives the high-temperature and high-pressure gas at the initial high-pressure holding time T1 of the inflation gas from the inflator 21.

The double-stitch sewing part 14d is located on the front surface of the first development part 11a in a state where the first development part 11a is deployed, and a center sewing part 141 extending in the vertical direction at the center in the left-right direction, and left and right from the center sewing part 141. Left and right sewing parts 142 extending in the vertical direction at spaced positions. The center sewing portion 141 includes an upper sewing portion 141a of one base cloth 12 and one base cloth 12, and a lower sewing portion 141b of two base cloths 12 and two reinforcing patches 13.
1, the upper sewing portion 141a of the central sewing portion 141 is composed of the first type sewing portion 14-1 in FIG. 2, and the left and right sewing portions 142 are the second type sewing portion 14 in FIG. -2. Of the central sewing portion 141, the lower sewing portion 141b may be constituted by the first type sewing portion 14-1 of FIG. 4 or may be constituted by the single stitch 14s consisting only of the main sewing 14a of FIG. May be.
The sewing portion 14 other than the double stitch sewing portion 14d is composed of a single stitch sewing portion 14s shown in FIG.

Next, the operation and effect of the embodiment of the present invention will be described.
In the airbag 11 of the present invention, since at least a part of the sewing portion 14 is the double stitch sewing portion 14d, the tension applied to the sewing portion 14 when the airbag is deployed is the seam that is first applied with the tension when the airbag is deployed. It is possible to reduce the load on the seam (main stitch) 14a which is received by the (absorbing stitch) 14b and which is not initially tensioned when the airbag is deployed. As a result, compared to the single stitch 14s (or the single stitch 4s of the conventional airbag), the load resistance value and energy absorption amount of the airbag 11 at the time of deployment can be increased, and the airbag 11 at the time of deployment is sewn. It is possible to make it difficult to break the portion 14.
This can be seen from the comparison of the test results of the specifications (i) to (iii) and the specification (iv) in FIG. That is, the specification (iv) is larger in both the load resistance value and the amount of absorbed energy (the area under the load vs. stroke curve in FIG. 11 indicates the absorbed energy) than the specifications (i) to (iii). I understand.

In this case, the load resistance value and energy absorption of the airbag 11 can be increased simply by changing the sewing from the single stitch 14s to the double stitch 14d. There is no additional or enlargement or folding change of the airbag 11.
Further, if the main stitch 14a remains even if the thread breakage occurs in the absorption stitch 14b, there is no influence on the airbag deployment performance. Therefore, as long as the main stitch 14a can maintain the conventional strength, it is necessary to repeat the evaluation test. There is no.
Since the strength of the main stitch 14a is influenced by the sewing pitch pa of the main stitch 14a (as can be seen from the specifications (i) to (iii) in FIG. 11), the sewing pitch pa of the main stitch 14a is sewn by the conventional single stitch 4s. By making the pitch ps equal to or substantially equal to the pitch ps, it can be considered that the main sewing 14a maintains the conventional strength.

  Moreover, since the double stitch sewing part 14d contains at least one of the 1st type sewing part 14-1 and the 2nd type sewing part 14-2, it is the 1st type sewing part 14-1. When the second type sewing portion 14-2 is applied to the sewing portion shown in FIGS. 15 and 16 having the conventional structure shown in FIG. 14, the sewing portion shown in FIGS. Can be prevented.

  Further, since the sewing pitch pb of the absorption stitch 14b is made larger than the sewing pitch pa of the main stitch 14a, damage to the bag base fabric 12 at the absorption stitch 14b portion can be reduced, and the base fabric of the bag at the absorption stitch 14b portion is cut. Occurrence of (cutting of base cloth connecting the sewing machine holes) can be suppressed.

  Further, the sewing pitch pa of the main stitch 14a of the double stitch sewing portion 14d is equal to or substantially equal to the sewing pitch ps of the seam of the single stitch sewing portion 14s, so that the load resistance value of the double stitch sewing portion 14d is the absorption stitch 14b. As a result, the load resistance value of the single-stitch sewing portion 14 s is reliably increased, and the airbag 11 can be prevented from being broken.

  Specifically, when the sewing pitch pa of the main stitch 14a of the double-stitch sewing portion 14d is set to 2.5 mm, the load resistance value of the double-stitch sewing portion 4d is at least the conventional single stitch. A load resistance value of the sewing portion 4s (having a sewing pitch of 2.5 mm) can be secured.

  When the sewing pitch of the absorption stitch 14b is set to 4.5 mm, even if the sewing pitch of the main sewing 14a is set to 2.5 mm, the sewing pitch of the absorption sewing 14b is larger than the sewing pitch of the main sewing 14a. Can be bigger.

  When the double stitch sewing portion 14d is composed of the first type sewing portion 14-1 and the sewing interval d between the two stitches 14a, 14b of the double stitch sewing portion 14d is set to 5.0 mm, When the distance d is larger than a value within the range, the load resistance value becomes higher (for example, compared with a case where the sewing interval is 10 mm).

  When the double stitch sewing portion 14d is composed of the second sewing portion 14-2 and the sewing interval between the two stitches 14a and 14b of the double stitch sewing portion 14b is set in the range of 5 mm to 10 mm, the break is sewn. The mode becomes the mode due to the base cloth being cut off, and the load resistance value becomes higher than the breakage (breakage due to yarn breakage) at the first type sewing portion 14-1. This is clear from the comparison of the test results of FIG. 11 and FIG.

Since the airbag 11 has the 1st expansion | deployment part 11a and the 2nd expansion | deployment part 11b, and expand | deploys in order of the 1st expansion | deployment part 11a and the 2nd expansion | deployment part 11b, the high pressure holding time of the gas for expansion | swelling from an inflator By combining T1 with the development time of the first development part 11a, the double stitch sewing part 14d is provided only in the first development part 11a.
Thereby, it is not necessary to double stitch the entire sewing portion 14 of the airbag 11, and an increase in manufacturing cost due to the double stitching of the entire sewing portion 14 can be suppressed.

  Moreover, the adoption of an omni bag increases, and the sewing site | part 14 increases in connection with it, The problem of the increase in manufacturing cost has generate | occur | produced. However, by providing the double stitch sewing portion 14d only in the first development portion 14a, it is possible to alleviate the problem of an increase in the sewing portion 14 and an increase in manufacturing cost in the omni bag adoption.

  In addition, the double stitch sewing portion 14d is located on the front surface (front surface when viewed in the vehicle front-rear direction) of the first deployment portion 11a in a state where the first deployment portion 11a is deployed, and a central sewing portion extending in the vertical direction at the center in the left-right direction 141 and the left and right sewing parts 142 extending in the vertical direction at a position separated from the center sewing part 141 in the left and right directions, only the center sewing part 141 and the left and right sewing parts 142 are double stitched, so that a conventional airbag is obtained. Can prevent tearing.

DESCRIPTION OF SYMBOLS 11 Air bag 11a 1st expansion | deployment part 11b 2nd expansion | deployment part 12 Base fabric 13 Reinforcement patch 14 Sewing part 14a Main sewing 14b Absorption sewing 14d Double stitch (double stitch part)
14s single stitch (single stitch part)
14-1 First Type Sewing Portion 14-2 Second Type Sewing Portion 141 Central Sewing Portion 141a Central Sewing Portion Upper Sewing Portion 141b Central Sewing Portion Lower Sewing Portion 142 Left and Right Sewing Portions (Left and Right Sewing Portions)
15 Instrument upper panel 16 Airbag door 17 Integral flange 18 Skin 19 Windshield 20 Airbag case 21 Inflator pa Sewing pitch pb of double stitch 14d main stitch 14a Sewing pitch p of double stitch 14d absorption stitch 14b ps Single stitch 14s Sewing pitch d The distance between the main stitch 14a and the absorption stitch 14b of the double stitch 14d

Claims (6)

An airbag device including an airbag that is manufactured by sewing only a plurality of pieces of cloth constituting the pressure-resistant portion at a sewing portion and that is supplied with an inflation gas and deployed when a vehicle collides,
A part of the sewing part is a double stitch sewing part having two rows of seams formed at a sewing interval with each other,
The double stitch sewing portion includes a first type sewing portion that includes a sewing portion at a portion that is bent and extends from the outer surface of the airbag, and a second portion that includes a sewing portion at a portion that extends in the same direction as the outer surface of the airbag. Including at least one of the types of sewing parts,
The sewing pitch of the two stitches of the double stitch sewing portion is different from each other, and the sewing pitch of the absorption stitch, which is the seam that is initially tensioned when the airbag is deployed, is not initially tensioned when the airbag is deployed. square airbags device larger than the sewing pitch of the stitches is a seam. The airbag device according to claim 1, wherein the plurality of cloth pieces constituting the pressure-resistant portion include at least one of a base fabric and a reinforcing patch, and at the sewing portion, at least one of the base fabric and the reinforcing patch is sewn. The said 1st type sewing part consists of a sewing part which sews base fabrics, The said 2nd type sewing part consists of a sewing part which sews a reinforcement patch and a base fabric. Airbag device. The sewing portion other than the double stitch sewing portion includes a single stitch sewing portion, and a sewing pitch of the main stitch of the double stitch sewing portion is equal to or substantially equal to a sewing pitch of a seam of the single stitch sewing portion. 1-The airbag apparatus of any one of Claim 3 . The airbag comprises a passenger seat airbag folded and stored under the instrument upper panel of the vehicle before deployment,
The airbag has a first deployment portion that pushes open the instrument upper panel during deployment and deploys upward and rearward, and a second deployment portion that deploys rearward, up, down, left and right with respect to the first deployment portion. The airbag device according to any one of claims 1 to 4, wherein the airbag device is folded so as to be deployed in the order of the first deployment portion and the second deployment portion. The double stitch sewing portion is located on the front surface of the first development portion in a state where the first development portion is deployed, and a center sewing portion extending in the vertical direction at the center in the left-right direction, and separated from the center sewing portion in the left-right direction. Left and right sewing parts extending in the vertical direction at the position,
The central sewing portion is composed of the first type sewing portion, and the left and right sewing portions are composed of the second type sewing portion,
The first type sewing part is composed of a sewing part of a base cloth and a base cloth, or a base cloth and a reinforcement patch, and the second type sewing part is composed of a sewing part of the base cloth and the reinforcement patch. The airbag device according to claim 5.

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