JP2000159045A - Air bag and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the characteristics of an air bag for front passenger seat at the time of inflating in proximity and reduce the manufacturing costs. SOLUTION: The inside of an air bag 1 to be installed on an instrument panel opposing to a front passenger seat is partitioned by a partitioning wall 43 furnished with a communicating part 28. The center part of the wall 43 is coupled with a mounting part 30 by a band 24. When gas is introduced from an opening 31, a first compartment 41 is inflated, and then a second compartment 42 is inflated. The band 24 reduces the pressure to the occupant side when the air bag 1 is inflated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag used for an airbag apparatus for protecting a passenger in a passenger seat of an automobile, and a method of manufacturing the airbag.

[0002]

2. Description of the Related Art Heretofore, for example, an airbag device for a front passenger has been used which is provided on an instrument panel of an automobile and protects a front passenger. The airbag device is provided on an instrument panel facing an occupant in the passenger seat, and includes a retainer, an inflator housed inside the retainer, a folded airbag, and the like. . And, in a state where the control device detects the collision of the vehicle,
The inflator is activated to release gas into the airbag to inflate the airbag, restrain the occupant moving forward, and reduce the impact applied to the occupant.

[0003] With regard to an airbag used in this type of airbag device, at present, a deployment characteristic capable of reducing pressure on an occupant located out of a proper seating position is realized, and manufacturing costs are reduced. Are required.

In this respect, for example, Japanese Patent Application Laid-Open No. 6-344843.
There is known an airbag described in Japanese Patent Application Laid-Open Publication No. HEI 9-86,980. The airbag is provided with a guide member for partitioning the inside of the airbag into upper and lower portions so that the lower portion of the airbag is deployed earlier than the upper portion. However, this configuration has a problem that the size of the protrusion of the airbag toward the front side is not always effectively suppressed.

[0005] For example, see Japanese Patent Application Laid-Open No. H10-203280.
There is known an airbag described in Japanese Patent Application Laid-Open Publication No. HEI 9-86,980. The airbag further includes a bag-shaped inner bag inside the bag-shaped airbag body to stabilize the deployment behavior of the airbag. However, even in this configuration, there is a problem that the protruding dimension toward the front side of the airbag is not necessarily effectively suppressed, and the manufacturing process is complicated, and it is difficult to reduce the manufacturing cost.

[0006]

As described above, the configuration in which the guide member that partitions the inside of the airbag into upper and lower portions is provided has a problem that the size of the protrusion toward the front side of the airbag is not necessarily suppressed effectively. ing. Further, even in a configuration in which a bag-shaped inner bag is further provided inside the bag-shaped airbag body to stabilize the deployment behavior of the airbag, the protrusion dimension toward the front side of the airbag is not necessarily effective. In addition to this, there is a problem that the manufacturing process is complicated and it is difficult to reduce the manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an airbag and an airbag manufacturing method capable of easily improving deployment characteristics and reducing manufacturing costs. I do.

[0008]

The airbag according to claim 1, wherein the mounting portion is mounted on the instrument panel side facing the passenger seat, the first compartment into which gas is introduced, and the first compartment. A second branch located on the occupant side of the branch,
A partition wall dividing an internal space into the first compartment and the second compartment, and having a communication portion through which gas can flow;
And a connecting band connecting the mounting portion and the partition wall.

In this configuration, the gas introduced into the airbag first causes the first compartment to expand, and then
The partition is introduced into the second compartment through the communicating portion of the partition wall, and the second compartment is deployed. Further, since the partition wall is connected to the mounting portion by the connecting band, the projecting distance and pressure of the airbag from the instrument panel to the passenger seat side are suppressed, and particularly, the partition wall is positioned close to the instrument panel. The pressure applied to the occupant is reduced, and the deployment characteristics are easily improved.

The airbag according to claim 2 is provided with an opening having a predetermined width for gas introduction, an attachment portion attached to a member to be attached, a first compartment into which gas is introduced, and A second branch located on the front side of the first branch;
A partition wall dividing an internal space into the first compartment and the second compartment, and having a communication portion through which gas can flow;
And a connecting band connecting the mounting portion and the partition wall, facing the opening, and having a width dimension equal to or larger than the opening.

In this configuration, the gas introduced into the airbag first causes the first compartment to expand, and then
The partition is introduced into the second compartment through the communicating portion of the partition wall, and the second compartment is deployed. Further, since the partition wall is connected to the mounting portion by the connection band, the protruding distance and pressure of the airbag toward the front side are suppressed, and the deployment characteristics are easily improved. Further, since the connecting band connected to the partition wall faces the opening and has a width dimension larger than the opening, it effectively regulates the gas flow, improves the deployment characteristics easily, and reduces the number of parts. Is also suppressed, and the manufacturing cost is suppressed.

According to a third aspect of the present invention, there is provided an airbag having an upper surface, a pair of upper side surfaces extending from both sides of the upper surface, and an upper partition surface extending from a tip of the upper surface. A first base cloth, a lower surface portion, a pair of lower side surface portions extending from both sides of the lower surface portion and joined to the upper side surface portion, and extending from a front end portion of the lower surface portion to the upper partition surface portion; A second base cloth provided with a lower partition surface part that is joined to form a partition wall, and joined to the first base cloth and the second base cloth so as to cover front sides of the upper partition surface part and the lower partition surface part; The third base cloth and the front end are joined to at least one of the upper partition surface and the lower partition surface, and the base end is formed of the first base cloth and the second base cloth. And a connecting band joined near at least one base end. Than it is.

In this configuration, the gas introduced into the airbag first causes the first compartment to expand, and then
The partition is introduced into the second compartment through the communicating portion of the partition wall, and the second compartment is deployed. Further, since the partition wall is connected to the mounting portion by the connection band, the protruding distance and pressure of the airbag toward the front side are suppressed, and the deployment characteristics are easily improved. Further, the number of parts is small, the configuration is simple, and the manufacturing cost can be reduced.

The airbag according to a fourth aspect is the airbag according to any one of the first to third aspects, wherein the partition wall comprises:
The communication portion is provided near the peripheral portion.

In this configuration, the first compartment can be widely and flatly deployed to the vicinity of the peripheral portion, and the deployment characteristics can be easily improved.

The airbag according to the fifth aspect is the airbag according to any one of the first to fourth aspects, wherein:
It is provided with an elongated portion in which portions separated in the longitudinal direction are restrained so as to be breakable.

In this configuration, in the initial state of the deployment of the airbag, the longitudinal dimension of the connecting band is shortened by the extension portion, the projection distance and the pressure in the initial stage of the deployment of the airbag are suppressed, and the airbag is restrained by the gas pressure. With the part broken,
The extension part is extended to secure the capacity of the airbag and improve the deployment characteristics.

According to a sixth aspect of the present invention, there is provided a method of manufacturing an airbag.
A first base cloth provided with an upper surface, a pair of upper side surfaces extending from both sides of the upper surface, and an upper partition surface extending from a tip of the upper surface; a lower surface; A pair of lower side surfaces extending from both sides of the lower portion, and a lower partition surface extending from a tip of the lower surface.
, A third base cloth, and a connecting band, and the base ends of the first base cloth and the second base cloth and the ends of the upper side surface and the lower side surface are connected to each other. The first and second base fabrics are joined together near the base end of at least one of the first base fabric and the second base fabric, and the upper partition surface and the lower partition surface are positioned outside. Then, the outer peripheral portion of the third base fabric is joined along an opening formed by the front end portion of the first base fabric and the second base fabric to form a bag, The bag is turned over through an opening provided in the vicinity of at least one base end of the base cloth and the second base cloth, and the front end of the connection band is formed by the upper partition surface and the lower side surface. To be joined to the front end.

With this configuration, an airbag with good deployment characteristics can be manufactured with a small number of parts and a simple operation, and the manufacturing cost can be reduced. Further, in the manufactured airbag, the gas introduced into the airbag firstly deploys the first compartment, and then is introduced into the second compartment through the communication part of the partition wall, and the second compartment is opened. In addition, since the partition wall is connected to the mounting portion by the connecting band, the distance of the protrusion of the airbag to the front side and the pressure are suppressed, and the deployment characteristics are easily improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an airbag and a method for manufacturing the airbag according to the present invention will be described below with reference to the drawings.

1 to 4, reference numeral 1 denotes an airbag. The airbag 1 is provided on an instrument panel 4 opposed to a passenger seat of a vehicle body 3 of a vehicle which is a moving body. The device 5 is provided. Hereinafter, the front-rear direction will be described in accordance with the front-rear direction of the vehicle body 3, and in the present embodiment, the front side of the airbag 1, that is, the protruding direction of the airbag 1 is rearward. In addition, the direction intersecting the protruding direction is the up-down direction, and depending on the protruding state of the airbag 1, the up-down direction may overlap the front-rear direction.

As shown in FIGS. 2 and 3, the airbag device 5 includes a case-shaped retainer 12 having an upper side with a projecting opening 11, and a gas injecting gas to a lower side of the retainer 12. A cylindrical inflator 14 is housed, and a folded bag-shaped airbag 1 is housed above the inflator 14. Further, in a normal state, the projecting opening 11 is covered by a cover (not shown).

The airbag device 5 activates the inflator 14 to release gas such as nitrogen gas into the airbag 1 when the control device (not shown) detects a collision of the vehicle. Is expanded and deployed. Then, by the pressure of the inflation of the airbag 1, the cover body is cleaved at a predetermined tear line to form a projection, and the airbag 1 is projected from the projection. Then, the airbag 1 is inflated and deployed in the shape of a side fan in front of the occupant in the front passenger seat along the space between the upper surface of the instrument panel 4 and the windshield 16 to restrain the occupant moving forward. In addition, the shock applied to the occupant is reduced.

As shown in FIGS. 1 to 4 and the like, the airbag 1 mainly includes two main panels of a first base cloth 21 and a second base cloth 22, and one third base cloth 22. And a connecting band 24 made of the base cloth. The base cloths 21 to 24 are made of a woven cloth such as nylon 66, and the connecting band 24 uses a base cloth having air permeability.

The first base fabric 21 has a substantially rectangular upper surface portion 21a, a pair of substantially fan-shaped upper side surface portions 21b extending from both sides of the upper surface portion 21a, and a pair of substantially fan-shaped upper side surface portions 21a. An upper partition surface portion 21c extending from the distal end portion is provided integrally. A circular exhaust hole, that is, a vent hole 26 is formed in the vicinity of the distal end of each upper partition surface 21c. Further, a plurality of circular communication portions (communication holes) are formed on the upper partition surface portion 21c along the outer peripheral portion excluding the distal end portion.
28 are formed.

The second base cloth 22 has a substantially rectangular lower surface portion 22a, a pair of substantially fan-shaped lower side surface portions 22b extending from both sides of the lower surface portion 22a, and a lower surface portion 22a. A lower partition surface portion 22c extending from the distal end portion is provided integrally. Further, on the lower surface portion 22a, an attachment portion 30 attached to the retainer 12 is provided near the base end portion, and the attachment portion 30 has a rectangular shape having a predetermined width dimension connected to the inflator 14. An opening (inflator mounting port) 31 is formed. Further, a plurality of through holes 32 are formed along the vicinity of the edge of the opening portion 31, and mounting tools 34 such as bolts and nuts or rivets inserted into these through holes 32.
Thereby, the mounting portion 30 is fixed to the retainer 12, that is, the instrument panel 4 side. Further, a plurality of circular communication portions (communication holes) 28 are formed along the outer peripheral portion excluding the distal end portion of the lower partition surface portion 22c.

The third base fabric 23 is formed in a substantially rectangular shape in which both sides have a substantially circular arc shape.

The connecting band 24 is also called a tether, a belt or a tether belt, and has an elongated rectangular shape. The width of the connecting band 24 is equal to or larger than the width of the opening 31 of the second base cloth 22. Are formed to have approximately equal width dimensions.

The assembly process of the airbag 1 is as follows.
First, as shown in FIGS. 4 and 5A, each part is cut. Then, as shown in FIG. 5 (b), the upper partition surface 21c of the first base cloth 21 is folded back to the inside of the bag, and the two sides 21d on both sides are joined to the upper surface 21a by sewing or the like. Similarly, as shown in FIG. 5C, the lower partition surface 22c of the second base cloth 22 is folded back to the inside of the bag, and the two sides 22d on both sides are joined to the lower surface 22a by sewing or the like. . Although not shown, the mounting portion 30 of the second base cloth 22 and the like include:
If necessary, a flameproof cloth for increasing heat resistance, a reinforcing cloth for increasing strength and the like can be overlapped and joined by sewing or the like.

Next, as shown in FIG. 5 (d), the first base cloth 21 and the second base cloth 22 are overlapped with the partition surfaces 21c, 22c facing outward, and the connecting band 24 is connected to the second base cloth 22. Of the base cloth 22 and the three sides 36 except for the distal end side are joined by sewing or the like. In this state, the upper and lower side portions 21b and 22b are joined to each other to form a fan-shaped side portion.

Next, as shown in FIG. 5 (e), the members sewn to each other are expanded in a conical shape with the opening 31 facing upward, and the entire periphery of the opening at the bottom is covered with the outer periphery of the third base cloth 23. It is joined to the portion 37 by sewing or the like, so that a bag-like state shown in FIGS. 5F and 6A is obtained.

Subsequently, as shown in FIG.
The bag is turned upside down so that the third base cloth 23 is picked up from the base cloth 31 to obtain a bag-like state shown in FIG.

Then, as shown in FIG. 6 (c), the leading ends of the partition surfaces 21c, 22c are temporarily pulled out from the opening 31, overlapped with the leading end of the connecting band 24, and joined by sewing or the like. As a result, as shown in FIG.
The airbag 1 for the passenger seat having three layers in the chamber is completed. That is, as shown in FIGS. 1 and 2, a first compartment 41 communicating with the opening 31 and a second compartment 42 located on the occupant side are joined to each other in the airbag 1. Face part 21c
, 22c are partitioned by a partition wall (internal partition) 43, and the first compartment 41 is vertically partitioned by the connecting band 24.

As shown in FIG. 2, the airbag 1 is protruded from the upper surface of the instrument panel 4, and when the occupant is in a normal seating position, gas is supplied to the airbag 1 from the opening 31. When introduced, this gas first strikes the connecting zone 24 and deploys the lower part of the first compartment 41 and the upper part of the first compartment 41 via both sides of the connecting zone 24. Then, after the first compartment 41 is deployed in a substantially V-shape, the gas is introduced into the second compartment 42 via the communication portion 28, and the second compartment 42 is deployed. That is, as shown in FIG. 3, the airbag 1 is deployed in states I, II, and III to protect the occupant in the passenger seat.

Further, the gas in which the airbag 1 is deployed is
The air is directly exhausted from the vent hole 26 communicating with the second compartment 42 on the occupant side.

Further, the occupant may move the instrument panel 4
In the case of so-called close deployment in which the airbag 1 is deployed in a state close to the occupant, as shown in FIG. 7, the occupant is received while the first compartment 41 is deployed, and the gas is mainly guided downward, and the occupant is guided. The pressure applied to is regulated.

As described above, according to the present embodiment, the inside of the airbag 1 is divided into the first compartment 41 and the second
42, a time difference is generated in the deployment of the first compartment 41 and the second compartment 42, and the partition wall 43 has a central portion attached to the instrument panel 4 by the connecting band 24. Since the airbag 1 is connected to the portion 30 and regulated to a predetermined stroke, the airbag 1 can be rapidly deployed in the radial direction, particularly in the vertical direction, particularly in the downward direction, to protect the occupant, and at the front of the airbag 1, The protruding distance and pressure to the passenger seat side can be suppressed, and in particular, the pressure applied to the occupant located close to the instrument panel 4 can be easily reduced, and it is possible to cope with a so-called standing child. Effective deployment characteristics can be easily realized. That is, the deployment characteristics can be easily improved as compared with a configuration in which the lower portion of the airbag is simply deployed before the upper portion by the guide member.

Then, the connecting band 24 connected to the partition wall 43
Is opposed to the opening 31 into which gas is introduced, and the opening 31
Since it has the above width dimensions and is in a state of covering the opening 31,
The gas flow can be effectively guided, the deployment characteristics can be easily improved, and the manufacturing cost can be suppressed without increasing the number of parts.

Further, according to the present embodiment, the airbag 1 having a small number of parts, a simple structure, good suturing workability, and good deployment characteristics can be manufactured by a simple operation, and the manufacturing cost can be reduced. . That is, the manufacturing cost can be reduced as compared with a configuration in which a bag-shaped inner bag is further arranged in the airbag.

Further, since the communicating portion 28 of the partition wall 43 is formed near the peripheral portion, the first compartment 41 can be widely and flattened to the vicinity of the peripheral portion, and the deployment characteristics can be easily improved. .

In the above-described embodiment, the structure mounted on the upper surface of the instrument panel 4 has been described. However, the air bag of the air bag device mounted on the front side of the instrument panel or the rear surface of the seat is described. Can also be applied. For example, as shown in FIG. 8, in the case of an airbag device 5 attached to the front side of the instrument panel 4 on the occupant side, the connecting band 24 is attached below the opening 31 and gas is directed upward. By guiding, even in the case of the close deployment as shown in FIG. 8, the pressure on the occupant can be reduced.

Further, the connecting band 24 can be extended in length in a state where the gas pressure is applied, so that the deploying characteristics can be improved. For example, as shown in FIG. 9, an intermediate portion of the connecting band 24 is sewn with a breakable thread 50 to form an extended portion (restraining portion) 51. In an initial state of deployment of the airbag 1, the extended portion is extended. The length of the connecting band 24 is shortened by 51, the projecting distance and the pressure of the airbag 1 in the initial stage of deployment are suppressed, and the portion restricted by the gas pressure is broken,
By extending the airbag 51, the airbag 1 can be advanced to the position shown by the two-dot chain line B to secure the capacity of the airbag.

[0043]

According to the airbag of the first aspect, the gas introduced into the airbag first causes the first compartment to expand, and then to the second compartment via the communicating portion of the partition wall. Introduced to deploy the second compartment. And the partition wall is
Since the airbag is connected to the mounting part by the connecting band, the distance and pressure of the airbag from the instrument panel to the passenger seat can be reduced, and the pressure on the occupant located close to the instrument panel can be reduced. In addition, the deployment characteristics can be easily improved.

According to the airbag of the second aspect, the gas introduced into the airbag firstly deploys the first compartment, and then is introduced into the second compartment via the communicating portion of the partition wall. , Deploy the second branch. Further, since the partition wall is connected to the mounting portion by the connecting band, the protruding distance and pressure of the airbag toward the front side can be suppressed, and the deployment characteristics can be easily improved. Further, since the connecting band connected to the partition wall faces the opening and has a width dimension larger than the opening, the flow of gas can be effectively regulated, the deployment characteristics can be easily improved, and the number of parts can be easily improved. Increase can be suppressed, and the manufacturing cost can be suppressed.

According to the airbag of the third aspect, the gas introduced into the airbag first expands the first compartment, and then is introduced into the second compartment via the communicating portion of the partition wall. , Deploy the second branch. Further, since the partition wall is connected to the mounting portion by the connection band, the projecting distance and pressure of the airbag to the front side can be suppressed, and the deployment characteristics can be easily improved. Further, the number of parts is small, the configuration is simple, and the manufacturing cost can be reduced.

According to the airbag of the fourth aspect, in addition to the effects of any one of the first to third aspects, the partition wall is provided with the communication portion near the peripheral edge, so that the first compartment has the peripheral portion. It becomes possible to expand the flat area to the vicinity of the part, and the expansion characteristics can be easily improved.

According to the airbag of the fifth aspect, in addition to the effect of any one of the first to fourth aspects, in addition to the extension, the connecting body is provided with an extended portion in which portions separated in the longitudinal direction are restrained so as to be breakable. In the initial state of the deployment of the airbag, the longitudinal dimension of the connecting band is shortened by the extension portion, the projection distance and the pressure in the initial stage of the deployment of the airbag can be suppressed, and the portion restrained by the gas pressure is broken, By extending the extension portion, the capacity of the airbag can be secured and the deployment characteristics can be improved.

According to the method for manufacturing an airbag according to the sixth aspect, an airbag with good deployment characteristics can be manufactured with a small number of parts and simple operation, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an airbag according to the present invention in an unfolded state.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 showing an airbag device provided with the airbag.

FIG. 3 is an explanatory diagram showing an operation of deploying the airbag.

FIG. 4 is an explanatory view showing components of the airbag.

FIG. 5 is an explanatory diagram showing a manufacturing process of the airbag.

FIG. 6 is an explanatory diagram showing a manufacturing process of the airbag.

FIG. 7 is an explanatory diagram showing an operation of deploying the airbag.

FIG. 8 is an explanatory view of a deployment operation showing another embodiment of the airbag of the present invention.

FIG. 9 is a cross-sectional view showing still another embodiment of the airbag of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airbag 4 Instrument panel 21 1st base cloth 21a Upper surface 21b Upper side 21c Upper partition 22 Second base 22a Lower 22b Lower side 22c Lower partition 23 Third base 24 Connection Obi 28 Communication section 30 Mounting section 31 Opening section 41 First compartment 42 Second compartment 43 Partition wall 51 Extension

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukihiro Naito 218 Aoshima-cho, Fuji-shi, Shizuoka Prefecture Inside Japan Plastic Co., Ltd. (72) Inventor Katsumi Ishikawa 218 Aoshima-cho, Fuji-shi, Shizuoka Prefecture Japan Plastic Corporation ( 72) Inventor Takashi Ueda 218 Aoshima-cho, Fuji City, Shizuoka Prefecture F-term in Nippon Plastics Co., Ltd.

Claims (6)

[Claims] An attachment portion attached to an instrument panel facing a passenger seat; a first compartment into which gas is introduced; a second compartment located on the occupant side of the first compartment; A partition wall that divides the internal space into the first compartment and the second compartment and that has a communication portion through which gas can flow, and a connection band that connects the mounting portion and the partition wall. An airbag, characterized in that: 2. An opening having a predetermined width for gas introduction is provided, an attachment portion attached to a member to be attached, a first compartment into which gas is introduced, and a front side of the first compartment. A partition wall, which divides an internal space into the first and second compartments and has a communication portion through which gas can flow, the mounting portion and the partition wall, And a connecting band facing the opening and having a width dimension equal to or larger than the opening. A first base cloth having an upper surface, a pair of upper side surfaces extending from both sides of the upper surface, and an upper partition surface extending from a tip of the upper surface; A lower surface portion, a pair of lower side surface portions extending from both sides of the lower surface portion and joined to the upper side surface portion, and a partition wall extending from a front end portion of the lower surface portion and joined to the upper partition surface portion to constitute a partition wall. A second base cloth provided with a lower partition surface, and a third base cloth joined to the first base cloth and the second base cloth so as to cover the front sides of the upper partition surface and the lower partition surface. And a distal end joined to at least one of the upper partition surface and the lower partition surface, and a proximal end near at least one proximal end of the first base cloth and the second base cloth. Airbag, comprising: a connecting band joined to the airbag. . 4. The airbag according to claim 1, wherein the partition wall is provided with a communication portion near the peripheral edge. 5. The airbag according to claim 1, wherein the connecting body includes an extending portion in which portions separated in the longitudinal direction are restrained so as to be breakable. 6. A first base cloth having an upper surface, a pair of upper side surfaces extending from both sides of the upper surface, and an upper partition surface extending from a tip of the upper surface. A second base cloth provided with a lower surface, a pair of lower side surfaces extending from both sides of the lower surface, and a lower partition surface extending from a tip of the lower surface; and a third base cloth And a connecting band, the base ends of the first base cloth and the second base cloth and the ends of the upper side surface and the lower side surface are joined to each other, and the base end of the connecting band Is bonded to the vicinity of at least one base end of the first base fabric and the second base fabric, and the upper partition surface portion and the lower partition surface portion are located outside, and the third base fabric is An outer peripheral portion is joined along an opening formed by a distal end portion of the first base cloth and the second base cloth to form a bag, The bag is turned over through an opening provided near a base end of at least one of the first base cloth and the second base cloth, and a front end of the connection band is connected to the upper partition surface and the lower part. A method for manufacturing an airbag, wherein the airbag is joined to a tip portion with a side portion.