JPH08301047A - Module cover of air bag device - Google Patents

Abstract

PURPOSE: To improve cleavage without exposing a tear line to external appearance by respectively putting an angle of both side groove walls to form a part up to a midway part of a first slit of a module cover, an angle up to a midway part of a second slit continuing with the first slit by changing the direction and an angle up to final cleavage from a midway part in the specific relationship. CONSTITUTION: A first slit 43 is formed on the reverse side of a module cover 4, and a second slit 44 in the direction perpendicular to the first slit 43 is formed on its tail end P2 , and an H-shaped rupture line is formed. An angle α of both side groove walls to form a part up to a midway part of the first slit from a cleavage initial part P1 of the first slit 43, an angle β of both side groove walls to form a part up to a midway part of the second slit 44 from there and an angle γ of both side groove walls to form a part up to final cleavage P3 from there are respectively made constant, and are put in the relationship of (α<β<γ). As a result, A part up to a midway part of the first slit 43 becomes the acutest angle, and stress is easily received, and the stress is received in order, and cleavage is easily propagated to the second slit 44 from the first slit 43.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a module cover of an air bag device, and more particularly to a module cover of an air bag device for a driver seat mounted on a steering wheel of an automobile, the module cover being accurately aligned with the tear line when the air bag is deployed. The present invention relates to a module cover improved so as not to be torn and scattered.

[0002]

2. Description of the Related Art An airbag device for a driver's seat of an automobile is installed in a central portion of a steering wheel. The airbag device for a passenger seat has an airbag attached to a mounting plate generally called a retainer. A module cover is attached so as to cover these. And
Generally, a rib (vertical wall) for fixing the retainer to the retainer is formed on the back side of the module cover, and the inside of the rib is configured to accommodate a bag.

The module cover is provided with a tearing line (tear line) composed of a slit so that the line is split at a predetermined line when the airbag is activated. Generally, in the case of an H shape, the slit is a first slit provided in the center of the airbag cover in the vehicle width direction and a first slit provided in the vehicle front-rear direction along the left and right side edges and ribs of the cover. It is composed of two slits.

Each of the above slits is formed by continuously forming a groove at a portion of a tear line (tear line), forming a perforation, or deepening a groove at intervals. It has been known. In addition, in a module cover having a two-layer laminated structure of a hard layer and a soft layer, it is also known that a slit is formed in the hard layer along the tear line.

[0005]

As described above, in the conventional airbag device, the first slit is first split when the airbag is deployed, and the split slit is continuously propagated to the second slit to form the module cover. It greatly breaks. At this time, there is known a technique in which the wall thickness is made thicker toward the outer peripheral side than the wall thickness of the central portion of the cover so that the cleavage can be performed accurately.

However, in the case of the technique of changing the wall thickness, the tear line may be exposed from the outside, and at the time of molding, there are a part having a small cavity and a part having a large cavity (that is, a difference in wall thickness). There is the inconvenience that the fluidity of the resin material tends to deteriorate.

An object of the present invention is to solve the above-mentioned problems of the prior art, to secure the fluidity of the molding material at the time of molding without exposing the tear line on the appearance, and to improve the cleavage of the module cover. It is to provide a module cover for an airbag device.

[0008]

A module cover for an airbag apparatus according to claim 1 of the present invention is a module cover for an airbag apparatus for an automobile, which is provided with a slit for tearing the module cover when the airbag is deployed. The slit is configured to propagate continuously from the initial cleavage portion to the final cleavage position in the vicinity of the formation position of the hinge portion, and the slit has a first slit formed from the initial cleavage portion and the first slit. An angle (α) of both side groove walls formed by including a continuous second slit in a different direction and forming the first slit cleavage initial portion to the middle of the first slit, and the first slit from the middle of the first slit. Two
Angle of the groove walls on both sides forming part of the slit (β)
And the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage is constant and α <β <
It is characterized by having a relationship of γ.

The module cover of the airbag device according to claim 2 is a module cover of an automobile airbag device in which a slit is provided for tearing the module cover when the airbag is deployed. To the final cleavage position in the vicinity of the hinge portion formation position, the slit is continuous with the first slit formed from the initial cleavage portion and the first slit in a different direction. The angle (α) of the groove walls on both sides forming the first slit from the initial portion of the first slit cleavage to the middle of the first slit and the middle of the first slit to the middle of the second slit. The angle (β) of both side groove walls to be formed and the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage are α <β <γ There, alpha, beta, at least one of γ is characterized by being stepwise larger.

In the module cover of the airbag device according to claim 3 of the present invention, in the module cover of the automobile airbag device, which is provided with a slit for tearing the module cover when the airbag is deployed, the slit is the initial tearing portion. To the final cleavage position in the vicinity of the hinge portion formation position, the slit is continuous with the first slit formed from the initial cleavage portion and the first slit in a different direction. The angle (α) of the groove walls on both sides forming the first slit from the initial portion of the first slit cleavage to the middle of the first slit and the middle of the first slit to the middle of the second slit. The angle (β) of both side groove walls to be formed and the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage are α <β <γ There, alpha, beta, and at least one is gradually larger of gamma.

[0011]

In the invention according to claim 1, the angle (α) of both side groove walls forming from the initial portion of the first slit cleavage to the middle of the first slit, and the middle of the first slit to the middle of the second slit. And the angle (β) of the groove walls on both sides forming
Since the angles (γ) of the groove walls on both sides forming the middle of the second slit to the final cleavage are constant and α <β <γ, the first slit cleavage initial portion to the first slit are formed. Is the most acute angle and is susceptible to stress, then receives stress in the order from the middle of the first slit to the middle of the second slit, and further from the middle of the second slit to the final cleavage. The cleavage easily propagates to the second slit.

In the invention according to claim 2, the angle (α) of the groove walls on both sides forming from the initial portion of the first slit cleavage to the middle of the first slit and the middle of the first slit to the middle of the second slit. Angle of both side groove walls forming up to (β)
And the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage is α <β <γ, and α,
Since at least one of β and γ is formed larger stepwise, in this case as well, the initial cleavage side is more acute than the final cleavage position side and is more susceptible to stress, making cleavage easier. Will be propagated.

In the invention according to claim 3, the angle (α) of both side groove walls forming from the initial portion of the first slit cleavage to the middle of the first slit and the middle of the first slit to the middle of the second slit. Angle of both side groove walls forming up to (β)
And the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage is α <β <γ, and α,
Since at least one of β and γ is gradually formed to be large, in this case as well, the initial cleavage portion side is more acute than the final cleavage position side and is more susceptible to stress,
The cleavage will easily propagate.

In any of the above cases, since the plate thickness of the module cover is not changed, the tear line is not exposed on the appearance, the fluidity of the molding material at the time of molding is ensured, and the tear state of the module cover is improved. Can be improved.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. The members, arrangements, and the like described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.

1 to 14 show a reference example for explaining the present invention. FIG. 1 is a front view, FIG. 2 is a rear perspective view of an airbag cover, and FIG. 3 is a slit of the airbag cover. Explanatory drawing, FIG. 4 is an explanatory drawing showing a slit shape, FIG. 5 is a sectional view taken along line AA of FIG. 4, and FIG. 6 is a sectional view taken along line BB of FIG.
FIG. 7 is a graph for explaining an angle state, FIG. 8 is a graph for explaining an angle state of another example, FIG. 9 is a graph for explaining an angle state of yet another example, and FIG. 10 is an angle. 11 is a graph for explaining the state of FIG. 11, FIG. 11 is a sectional view taken along line CC of FIG. 2, FIG. 12 is a sectional view taken along line DD of FIG. 2, FIG. 13 is a sectional view taken along line EE of FIG. 1, and FIG. It is a FF sectional view.

The steering wheel S includes an annular grip portion 10a and an annular grip portion 1 as shown in FIG.
4 extended grip portions 10b extending inward from 0a
The airbag device E is disposed inside the extended grip portion 10b. The airbag device E of this example includes a bag 1, an inflator 2, and a retainer 3.
And the module cover 4 as main constituent elements.

The retainer 3 of this embodiment includes the retainer 3 shown in FIGS.
As shown by, a central hole 32 for mounting the inflator 2 is formed in the central part, and the peripheral edge of the opening of the bag 1 is held by the retainer 3 and the retainer ring 35, and is attached together with the inflator 2 and the retainer 3 with a fastener such as a screw. However, the retainer 3, the inflator 2, and the bag 1 are integrally assembled. The bag 1 of this example is stored and held by a known means.

A bent portion 33 bent toward the boss portion 5 is formed on both side ends of the retainer 3 of this embodiment, and the bent portion 33 has a rib 42 and a rib 42 formed on the module cover 4 at a predetermined position. The boss plate 7 attached to the boss portion 5 and the fastener 8 such as a screw or a rivet are integrally fixed.

The module cover 4 of this example has an upper surface portion 41.
Then, a rib 42 extending downward from the upper surface portion 41 is formed, and the rib 42 is formed so as to surround a range that covers the bag 1, the inflator 2, and the like.

On the rear surface side of the module cover 4 of this embodiment, as shown in FIG.
The first slit 43 is formed in the left / right direction), and the second slit 44 in the direction perpendicular to the first slit 43 is formed at both ends of the first slit 43 inside the base portion of the rib 42 at the end of the first slit 43. The first slit 43 and the second slits 44, 44 are formed on the side, and an H-shaped break line is formed. Therefore, the initial cleavage portion is used as the central portion of the cover of the first slit, and is configured to continuously propagate from the second slit 44 to the final cleavage position in the vicinity of the formation position of the hinge portion 45.

At the bottoms of the first slit 43 and the second slit 44, as shown in FIGS. 3 to 6, are R1 and R2 are formed. Further, the angle (α) of the groove walls on both sides of the radius R1 forming the first slit is constant. Similarly, the angle (β) of the groove walls on both sides of the radius R2 forming the second slit 44 is also constant. The angle (α) of the both-side groove walls and the angle (β) of the both-side groove walls are formed as α <β. That is, as shown in FIG. 7, which shows the center P1 of the first slit 43 that is the initial cleavage, the angle P2 that is the connecting portion of the first slit 43 and the second slit 44, and the final cleavage position P3, from P1 to P2. Is defined as an angle α, and P2 to P3 are defined as an angle β.

In this example, as shown in FIGS. 11 and 12, the center distance h1 of the radius R1 is smaller than the center distance h2 of the radius R2. That is, the radius center distance h1 in the radius shape on the initial cleavage side is shorter than the radius center distance h2 of the radius shape on the final cleavage position side, but h1 and h2 may be the same radius shape.

The module cover 4 constructed in this way
In that case, the airbag expands and the module cover 4
When is pressed from the back side, the first slit 43 first starts cleavage, but at this time, the angle α of the initial cleavage portion P1 of the first slit 43 is larger than the angle β of the second slit 44 than the angle of both side groove walls. Is narrow (becomes an acute angle), it is likely to receive stress, and the cleavage easily propagates.

That is, the angle (α) of both side groove walls of the first slit 43 and the angle (β) of both side groove walls of the second slit 44 are
Since it is formed as α <β, the stress is increased by the first slit 4
The first slit P of the first slit 4
Cleavage occurs at the central portion of 3, and this cleavage properly advances in the left-right direction toward the rib 42. Then, when the cleavage reaches the end of the first slit 43, the cleavage surely changes the traveling direction because the rib 42 is present in the forward direction of the traveling direction, and the first slit 43 and the second slit 44. The cleavage rapidly propagates from the connecting portion P2 to the second slit 44 side toward the final cleavage position P3.

In the above embodiment, the first slit 43 and the second slit 43
The angle (β) of the groove walls on both sides of the slit 44 is α <β, and both are formed constant.
As shown in FIG. 8, the angle (β) of the both side groove walls forming the second slit 44 is gradually changed to the final cleavage position while the angle (α) of the both side groove walls 3 is made constant. It can also be formed with a large angle. Even with this structure, the relationship that the stress exerts can be the same as that in the above-mentioned embodiment.

As another embodiment, the first slit 4
The angle (α) of both side groove walls of 3 is constant, and the angle (β) of both side groove walls forming the second slit 44 is gradually increased until the final cleavage position. You can also Even with this structure, the relationship that the stress exerts can be the same as that in the above-mentioned embodiment.

Further, as shown in FIGS. 9 and 10, the angle (α) of the groove walls on both sides of the first slit 43 may be increased as it approaches the second slit 44. That is, the angle (α) of the first slit 43 is continuously (gradually) provided that the condition of the angle α <β is satisfied.
Can also be configured close to the angle (β). Even with this configuration, the first slit 43 to the second slit 4
4. Further, the cleavage can be smoothly propagated to the final cleavage position P3.

Further, the angle (α) of the groove walls on both sides of the first slit 43 may be increased stepwise as it approaches the second slit 44. That is, the angle α
The angle (α) of the first slit 43 may be gradually made closer to the angle (β) on the condition that the condition of β is satisfied. Even with this configuration, the cleavage can be smoothly propagated from the first slit 43 to the second slit 44 to the final cleavage position P3.

The end point of the first slit 43 and the start point of the second slit 44 may be continuous points or may be formed with a step. That is, the first slit 43
When the end point of and the starting point of the second slit 44 are continuous,
When the structure is as shown in FIG. 10 and a step is provided,
It becomes the structure like.

FIG. 15 shows a module cover of an automobile airbag apparatus provided with a slit for opening the module cover when the airbag is deployed. Of the first slit formed from the initial cleavage portion, and the second slit that is continuous with the first slit in a different direction from the first slit, The angle (α) of both side groove walls forming from the initial portion of the first slit cleavage to the middle of the first slit and the angle (β) of both side groove walls forming from the middle of the first slit to the middle of the second slit. And the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage is constant and has a relationship of α <β <γ. .

The angle (α) of the groove walls on both sides forming from the initial portion of the first slit cleavage to the middle of the first slit,
The angle (β) of both side groove walls forming from the middle of the first slit to the middle of the second slit and the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage are α
There is a relationship of <β <γ, and at least one of α, β, and γ may be formed to be large stepwise.

Further, from the initial portion of the first slit cleavage to the first
Angle of the groove walls on both sides forming the middle of the slit (α)
And the angle (β) of both side groove walls forming the middle of the first slit to the middle of the second slit and the angle (γ) of both side groove walls forming the middle of the second slit to the final cleavage.
However, there is a relationship of α <β <γ, and at least one of α, β, and γ may be gradually formed larger.

That is, in FIG. 15, α, β, and γ are constant under the relationship of α <β <γ, and FIG.
Shows an example in which α, β, and γ are all gradually increased, but at least one of α, β, and γ is gradually increased, and the others are made constant or gradually increased. Can be configured as follows. Thus α <β <γ
It is possible to combine the relationships shown in FIG. 15 and FIG. 16 or to configure FIG. 16 as a gradual change and combine them on condition that the relationship of is satisfied.

[0035]

According to the first aspect of the present invention, the angle (α) of the groove walls on both sides forming from the initial portion of the first slit cleavage to the middle of the first slit, and the second slit from the middle of the first slit. The angle (β) of the groove walls on both sides forming the middle of the second slit and the angle (γ) of the groove walls on both sides forming the middle of the second slit to the final cleavage are constant and α
Since it is formed in a relationship of <β <γ, the first slit from the initial cleavage portion to the middle of the first slit is the most acute angle and is susceptible to stress, and then from the middle of the first slit to the middle of the second slit, Furthermore, stress is applied in the order from the middle of the second slit to the final cleavage, and the cleavage easily propagates from the first slit to the second slit.

In the invention according to claim 2, the angle (α) of the groove walls on both sides forming from the initial portion of the first slit cleavage to the middle of the first slit and the middle of the first slit to the middle of the second slit. Angle of both side groove walls forming up to (β)
And the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage is α <β <γ, and α,
Since at least one of β and γ is formed larger stepwise, in this case as well, the initial cleavage side is more acute than the final cleavage position side and is more susceptible to stress, making cleavage easier. Will be propagated.

In the invention according to claim 3 of the present application, the angle (α) of both side groove walls forming from the initial portion of the first slit cleavage to the middle of the first slit and the middle of the first slit to the middle of the second slit. Angle of both side groove walls forming up to (β)
And the angle (γ) of both side groove walls forming from the middle of the second slit to the final cleavage is α <β <γ, and α,
Since at least one of β and γ is gradually formed to be large, in this case as well, the initial cleavage portion side is more acute than the final cleavage position side and is more susceptible to stress,
The cleavage will easily propagate.

Further, in any of the above cases, since the plate thickness of the module cover is not changed, the tear line is not exposed on the appearance, the fluidity of the molding material at the time of molding is secured, and the tear state of the module cover is improved. Can be improved.

In any of the above cases, since the plate thickness of the module cover is not changed, the tear line is not exposed on the appearance, the fluidity of the molding material at the time of molding is ensured, and the tear state of the module cover is improved. Can be improved.

[Brief description of drawings]

FIG. 1 is a front view of a steering wheel including an airbag.

FIG. 2 is a rear perspective view of an airbag cover.

FIG. 3 is an explanatory diagram of slits of an airbag cover.

FIG. 4 is an explanatory diagram showing a slit shape.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

6 is a sectional view taken along line BB of FIG.

FIG. 7 is a graph illustrating an angle state.

FIG. 8 is a graph illustrating another example of an angle state.

FIG. 9 is a graph illustrating another example of the angle state.

FIG. 10 is a graph diagram illustrating a state of an angle of still another example.

11 is a cross-sectional view taken along line CC of FIG.

12 is a cross-sectional view taken along the line DD of FIG.

13 is a sectional view taken along line EE of FIG.

14 is a cross-sectional view taken along the line FF of FIG.

FIG. 15 is a graph illustrating an angle state according to an embodiment of the present invention.

FIG. 16 is a graph illustrating another example of the angle state.

[Explanation of symbols]

1 bag 2 inflator 3 retainer 4 module cover 10a annular grip portion 10b extended grip portion 32 center hole 33 bent portion 35 retainer ring 41 upper surface portion 42 rib 43 first slit 44 second slit 45 hinge portion P1 initial cleavage portion P2 second Connection between 1 slit and 2nd slit P3 Final cleavage position R1 R2 R2 h1 R1 center distance of R1 h2 R2 center distance of α Both slit wall of the first slit slit initial part to the middle of the first slit Angle β Angle of both side groove walls forming from the middle of the first slit to the middle of the second slit γ Angle of both side groove walls forming from the middle of the second slit to the final cleavage E Airbag device S Steering wheel

Claims (3)

[Claims] 1. A module cover for an automobile airbag apparatus, which is provided with a slit for tearing the module cover when the airbag is deployed, wherein the slit is continuous from the initial tearing portion and is close to the hinge formation position. The slit is configured to propagate to the cleavage position, and the slit has a first portion formed from the initial cleavage portion.
An angle (α) of both side groove walls that are formed to include a slit and a second slit that is continuous in a different direction from the first slit and that forms from the first slit cleavage initial portion to the middle of the first slit, The angle (β) of the groove walls on both sides forming from the middle of the first slit to the middle of the second slit,
A module cover for an airbag device, wherein the angles (γ) of the groove walls on both sides forming from the middle of the slit to the final cleavage are constant and α <β <γ. 2. A module cover for an automobile airbag apparatus, which is provided with a slit for tearing the module cover when the airbag is deployed, wherein the slit is continuous from the initial tearing portion and is close to a final position near the hinge formation position. The slit is configured to propagate to the cleavage position, and the slit has a first portion formed from the initial cleavage portion.
An angle (α) of both side groove walls that are formed to include a slit and a second slit that is continuous in a different direction from the first slit and that forms from the first slit cleavage initial portion to the middle of the first slit, The angle (β) of the groove walls on both sides forming from the middle of the first slit to the middle of the second slit,
The angles (γ) of the groove walls on both sides forming from the middle of the slit to the final cleavage are in the relationship of α <β <γ, and at least one of α, β and γ is formed to be large stepwise. The module cover of the characteristic airbag device. 3. A module cover for an automobile airbag apparatus, which is provided with a slit for tearing the module cover when the airbag is deployed, wherein the slit is continuous from the initial tearing portion and is close to a final position near the hinge formation position. The slit is configured to propagate to the cleavage position, and the slit has a first portion formed from the initial cleavage portion.
An angle (α) of both side groove walls that are formed to include a slit and a second slit that is continuous in a direction different from that of the first slit and that forms the first slit cleavage initial portion to the middle of the first slit, The angle (β) of the groove walls on both sides forming from the middle of the first slit to the middle of the second slit,
The angle (γ) of both side groove walls forming from the middle of the slit to the final cleavage has a relationship of α <β <γ, and at least one of α, β and γ is gradually formed to be large. A module cover for the airbag device.