JP2005212664A - Deployment restraining structure of air bag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deployment restraining structure of an air bag capable of restraining initial expansion of an air bag cushion using a strap holding a folded condition of the air bag cushion. <P>SOLUTION: Outside of an air bag cushion 2 is bounded, and first and second rupture parts 5, 6 gradually ruptured according to tension acting when expanding the air bag cushion 2 and restraining expansion speed of the air bag cushion 2 are provided to a strap 4 holding a folded condition. Therefore, the initial expansion of the air bag cushion 2 is restrained with a simple constitution and without increase of the number of parts, so as to effectively restrain an initial reaction force against occupants. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an airbag deployment restriction structure mounted on a vehicle such as an automobile.

  The airbag is deployed by inflating the airbag cushion at the time of the collision of the automobile, and the occupant is protected by the deployed airbag cushion. The inflation of the airbag cushion introduces a high-pressure gas rapidly. Therefore, the expansion speed is large and the initial reaction force against the occupant tends to increase.

Therefore, by providing a string-like body (tether) that resists in the deploying direction inside the airbag cushion, and breaking the string-like body with the initial inflation force, the amount of the airbag cushion popping out at the initial stage during inflation Is known (see, for example, Patent Document 1).
JP-A-7-277124 (page 3, FIG. 1)

  However, in the conventional airbag deployment regulation structure, it is necessary to attach a string-like body inside the airbag cushion, and the number of parts increases and the structure of the airbag cushion itself becomes complicated. It will increase, and this will affect the product unit price.

  Therefore, the present invention uses a strap that is used to hold the folded state of the airbag cushion, and the airbag deployment regulation structure that can regulate the initial inflation of the airbag cushion without increasing the number of parts. Is to provide.

The present invention relates to an airbag that retains its shape by binding the folded state of the airbag cushion with a strap that breaks when the airbag cushion is inflated.
The main feature is that the strap is provided with a plurality of breaking portions that are broken in stages according to the tension acting when the airbag cushion is inflated to regulate the inflation speed of the airbag cushion.

  According to the present invention, the strap that holds the folded state of the airbag cushion is effectively used, and the strap is provided with a plurality of breakage portions, whereby the strap is broken stepwise according to the tension at the time of inflation. Since the inflation rate of the bag cushion can be regulated, the initial reaction force against the occupant can be controlled by simply regulating the initial inflation of the airbag cushion without increasing the number of parts, with a simple configuration of providing multiple breaks in the existing strap. Can be effectively suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 4 show a first embodiment of an airbag deployment regulating structure according to the present invention, FIG. 1 is a perspective view of a folded state of an airbag cushion, and FIG. 2 is a state in which a first fracture portion of a strap is broken. FIG. 3 is a perspective view of the airbag cushion, FIG. 3 is a perspective view of the airbag cushion to be inflated by breaking the second fracture portion, and FIG. 4A is a side view of the airbag cushion in an initial deployed state (b) ) Is a side view of the airbag cushion in a fully deployed state.

  As shown in FIG. 1, the airbag 1 of the first embodiment includes an airbag cushion 2 and is inflated by introducing high-pressure gas from an inflator outside the figure into the airbag cushion 2 at the time of a collision. Protect.

  As shown in FIG. 4, the airbag 1 according to the present embodiment is set at the center of a steering wheel 3 of an automobile, and is normally a module case in which the airbag cushion 2 is folded and provided at the center of the steering wheel 3. It is stored inside.

  The module case has the airbag cushion 2 stored therein, and the storage opening is covered with a lid (not shown) to improve the appearance. When the airbag cushion 2 is inflated, the lid is pushed out from the cut and deployed. It has become.

  As shown in FIG. 1, the folded state of the airbag cushion 2 is configured to hold the shape by tying the outside with a strap 4, and the strap 4 is broken when the airbag cushion 2 is inflated. The restraint is released.

  Here, in the present embodiment, the strap 4 is broken in stages according to the tension acting when the airbag cushion 2 is inflated, and the first break as a plurality of fracture portions that regulate the inflation speed of the airbag cushion 2. The part 5 and the 2nd fracture | rupture part 6 are provided.

  The first and second fractured portions 5 and 6 are provided in a folded portion 7 formed in the middle of the strap 4, and the folded portion 7 overlaps the intermediate portion of the strap 4 over a predetermined length L. Folded, the tip 7a is tilted to one side and joined to the general portion 4a of the strap 4 by sewing S1. At this time, the folded portion 7 is folded toward the inside of the airbag 1.

  The first breaking portion 5 is formed by adjusting the coupling force by the sewing S1 of the tip portion 7a of the folded portion 7 and setting the sewing S1 portion to break at the initial tension, The two fractured portions 6 are formed by perforated cuts C provided in the inner side surface 7b of the folded-back portion 7, particularly in the present embodiment, the front end bent portion 7c of the inner side surface 7b.

  Therefore, when the airbag cushion 2 is inflated, the first and second broken portions 5 and 6 are tensions acting on the strap 4 by the inflation force of the airbag cushion 2, as shown in FIG. 1 rupture portion 5 breaks to an initial deployed state, and then, as shown in FIG. 3, the second rupture portion 6 breaks, and the second rupture portion 6 breaks, so that the binding force by the strap 4 is lost. The airbag cushion 2 is fully deployed.

  At this time, the first rupture portion 5 serving as the initial rupture portion has a predetermined bonding force by the sewing S1, and after the first rupture portion 5 breaks, the folded portion 7 reaches the second rupture portion 6. As shown in FIG. 2, the airbag cushion 2 has a function of maintaining the initial deployed shape for a certain period of time while the folded portion 7 extends.

  According to the airbag deployment restricting structure of the first embodiment having the above configuration, when high-pressure gas is introduced from the inflator due to a collision and the airbag cushion 2 starts to expand and tension is applied to the strap 2, The first fracture portion 5 is fractured and is in an initial deployed state as shown in FIGS. 2 and 4A.

  Then, when a larger tension is applied to the strap 4 by introducing further high-pressure gas from this initial developed state, the second fracture portion 6 is broken as shown in FIG. 3, and as shown in FIG. 4 (b). The airbag cushion 2 is in a fully deployed state and receives the occupant D moving forward due to inertial force with a buffer function.

  At this time, since the strap 2 is provided with the first breaking portion 5 and the second breaking portion 6, the strap 2 can be broken stepwise according to the tension when the airbag cushion 2 is inflated. Since the inflation speed of the cushion 2 can be regulated, the initial expansion of the airbag cushion 2 can be regulated without increasing the number of parts with a simple configuration in which the first and second broken portions 5 and 6 are provided in the existing strap 2. And the initial reaction force with respect to the passenger | crew D can be suppressed effectively.

  Further, in the present embodiment, in addition to the above-described effects, the first breaking portion 5 is provided at the tip coupling portion 7a of the folded portion 7 formed in the middle of the strap, and the inner side surface 7b (in this embodiment) Since the second rupture portion 6 is provided at the distal bent portion 7c), the structure for providing the first and second rupture portions 5 and 6 can be simplified to suppress a significant increase in manufacturing cost. Each of the broken portions 5 and 6 can function reliably.

  Furthermore, since the first breaking portion 5 has a function of holding the initial deployment shape of the airbag cushion 2 for a certain period of time, the reaction force characteristic to the occupant D can be further improved.

  Furthermore, since the folded portion 7 is folded toward the inside of the airbag 1, the strap 4 is hooked on the rear surface of the lid of the module case housing the airbag cushion 2 when the airbag cushion 2 is initially deployed. The airbag cushion 2 can be smoothly deployed.

  FIG. 5 shows a second embodiment of the present invention, in which the same components as those in the first embodiment are denoted by the same reference numerals and redundant description is omitted, and FIG. 5 shows the airbag cushion in a folded state. It is a perspective view.

  The airbag deployment restricting structure of the second embodiment is basically the same as that of the first embodiment, and the main difference from the first embodiment is that both end bases 4b and 4c of the strap 4 are provided. That is, the airbag cushion 2 is joined by sewing S2.

  Therefore, according to the second embodiment, the airbag cushion 2 is unfolded by regulating the shape of the airbag cushion 2 to the initial deployed state by the first breaking portion 5 as well as the same effects as the first embodiment. At this time, since both end bases 4b and 4c of the strap 4 are sewn S2, the airbag cushion 2 is not displaced with respect to the strap 4, and it is possible to prevent the deployment regulation from becoming unstable. it can.

  By the way, the airbag deployment restricting structure of the present invention has been described by taking the first and second embodiments as examples. However, the present invention is not limited to these embodiments, and other embodiments are within the scope of the present invention. Various types can be adopted.

It is a perspective view of the folded state of the airbag cushion in 1st Embodiment of this invention. It is a perspective view of an airbag cushion in the state where the 1st fracture part of the strap in a 1st embodiment of the present invention fractured. It is a perspective view of the airbag cushion which the 2nd fracture | rupture part in 1st Embodiment of this invention fractures | ruptures and intends to fully inflate. (A) in 1st Embodiment of this invention is a side view of the initial deployment state of an airbag cushion, (b) is a side view of the full deployment state of an airbag cushion. It is a perspective view of the folded state of the airbag cushion in 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airbag 2 Airbag cushion 4 Strap 4a The general part of a strap 4b, 4c The both ends base part of a strap 5 1st fracture | rupture part 6 2nd fracture | rupture part 7 Folding part 7a Tip part 7b Folding part inner surface

Claims (5)

In an airbag that retains its shape by binding the folded state of the airbag cushion with a strap that breaks when the airbag cushion is inflated,
An airbag deployment regulation structure, wherein the strap is provided with a plurality of fracture portions that are broken in stages according to a tension acting when the airbag cushion is inflated to regulate an inflation speed of the airbag cushion. In the middle of the strap, form a folded part that joins the tip part to the general part of the strap,
The plurality of broken portions are provided on the inner surface of the folded portion of the folded portion, the first broken portion that is broken at an initial tension provided at the tip coupling portion of the folded portion, and the strap is completely removed after the first broken portion is broken. The airbag deployment restriction structure according to claim 1, wherein the airbag deployment restriction structure is formed by a second breaking portion that breaks into two.   The airbag deployment restriction structure according to claim 2, wherein the folded portion is folded toward the inside of the airbag.   The airbag breakage restricting structure according to any one of claims 1 to 3, wherein the plurality of breakage portions have a function of holding the initial deployment shape of the airbag cushion for a predetermined time at the initial breakage portion. . The airbag deployment restriction structure according to any one of claims 1 to 4, wherein the strap has both end bases coupled to an airbag cushion.

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