JPH072336Y2 - Airbag cover - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an air bag cover provided in an air bag device for a vehicle.

[Prior Art] An air bag device is attached to a steering wheel or an instrument panel, and an air bag bag is deployed in front of an occupant in a vehicle emergency to prevent the occupant from moving forward.

In this air bag device, normally, the air bag bag is concealed and protected, and is pressed from the inside by the air bag bag that expands in the event of a vehicle emergency, and the linear easy-to-break portion that is locally weakened by a groove or the like is broken. However, there is known one provided with an air bag cover having a structure for advancing the air bag bag through an opening formed by this.

As shown in FIG. 7, an air bag cover of this type is molded from a synthetic resin foam having a skin,
It is conceivable that the rupture easy portion is formed by the grooves 50A and 50B on both front and back surfaces, and the woven cloth 52 is embedded inward at the ends along the grooves 50A and 50B. . As shown in FIG. 8, the woven cloth 52 is made of a mesh fabric composed of wefts 54 and warps 56.

The woven cloth 52 is embedded as described above, because when the grooves 50A and 50B start to break, a tearing load acts from the break to try to tear apart the grooves 50A and 50B. This is because this is prevented so that only the grooves 50A and 50B are reliably broken.

The above-mentioned grooves 50A and 50B are substantially H-shaped as a whole, and the groove 50A at the center is first broken, and then the grooves 50B at both sides are formed.
By breaking the portion of, the hinge portion 51 is used as a hinge to open a part of the air bag cover to the double door. Therefore, a large tear load is applied to the periphery of the groove 50A where the breakage first starts.

However, in the air bag cover of this type that has been conventionally considered, the end of the woven cloth 52 located along the groove 50A is a so-called cut end that is still cut, and as shown in FIG. The warp yarn 56 around the angle is easily frayed, and the grooves 50A and 50B corresponding to the frayed portion are indicated by the break line A.
There is a possibility that other parts may be broken.

Further, as shown in FIG. 10, the groove 50A may be formed in a loop shape surrounding a design such as a mark at the central portion on the surface side of the air bag cover or the like. In such a case, a groove is formed on the back surface side of the air bag cover, opposite to the groove 50A on the front surface side, except for a portion corresponding to one curved portion of the loop-shaped portion. A portion along the groove formed on the back surface side becomes a breakable portion. On the other hand, the end portion of the woven cloth 52 has an uneven shape as shown in FIG. 11 so as to follow the groove shape formed on the back surface of the air bag cover.

Also in this case, the woven cloth 52 is easily frayed around the corner portion B similarly to the above, and is more easily frayed at the portion C than the corner portion B. As shown in FIG. 12, the warp 56 is frayed. There is a possibility that parts other than the grooves 50A and 50B may be broken as indicated by the break line A corresponding to the broken parts.

[Problems to be Solved by the Invention] In view of the above, the present invention has an end portion in which a concave portion is formed in an intermediate portion of a linear portion and an end portion in which a convex portion located in the concave portion is formed in an intermediate portion of the linear portion. And, a pair of mesh fabrics are embedded at opposite sides of the linearly extending easy-to-break portion, and is pressed from the inside by an inflating air bag bag to be broken at the easy-to-break portion, and formed by this breaking. In an air bag cover in which an air bag bag is advanced through an opening, it is an object of the present invention to improve reliability in which only the breakable portion is broken.

[Means for Solving the Problems] In the present invention, the above-mentioned problems are solved by a means in which the ears of the mesh woven cloth are located at the end portions of the mesh woven cloth that are located along the breakable portion.

[Operation] In the present invention which is the above-mentioned means, the other mesh fabric cloth having the recesses formed at the end portions of the mesh cloth fabric having the concave portions has the ears at the front end portions of both sides of the concave portion and the convex portions formed therein. The ears are located at the ends of the protrusions at the ends of the. As a result, the ears that are not easily frayed are guided to the portion where the tear strength is increased and the rupture progresses.

[Embodiment] FIG. 2 shows an air bag device having an air bag cover to which the present invention is applied in a state of being assembled to a steering wheel, and FIG. 3 shows the air bag device of FIG. 2 in a disassembled state. Indicated by.

The air bag device 10 is a hub portion of the steering wheel 12.
A base plate 14 is supported by 12A via a means (not shown), and an air bag bag body 16, an air bag cover 19, an inflator 20, etc. are attached to the base plate 14.

The air bag bag body 16 is stored in a folded state in the upper portion of the base plate 14, and the peripheral portion of the opening 16A is pressed against the ring plate 26 fixed to the base plate 14 via the bolts 22, nuts 24 and the rivets 25, and the base plate 14 is pressed.
It is fixed in close contact with 14. Also, air bag bag
16 is a hold plate 27 fixed to the base plate 14
Is held from both sides to maintain the folded posture.

The inflator 20 passes through the through hole 14A formed in the central portion of the base plate 14, the opening 16A of the air bag bag body 16 and the through hole 26A formed in the central portion of the ring plate 26, and the upper end portion thereof is an air bag bag. A flange 28, which protrudes inward from the body 16 and is provided in the middle portion, is fixed to the base plate 14 via the bolt 22 and nut 24. The inflator 20 is housed inside the inflator cover 30 fixed to the base plate 14 via the bolt 22 and nut 24.

The inflator 20 is filled with a gas generating substance, and when a vehicle equipped with an air bag device is significantly decelerated, the sensor detects this and starts combustion, and the generated gas is ejected from the opening 32 to produce an air bag bag. It is designed to inflate body 16.

An insert plate 40 located at the lower end of the air bag cover 18 is fixed to the base plate 14 via a rivet 34 to form a storage chamber for the air bag bag 16 together with the base plate 14. On the surface of the air bag cover 18,
As shown in detail in FIG. 1, grooves 36A and 36B which are substantially H-shaped as a whole are formed, and a loop shape is formed at the center of the groove 36A. Also, on the back surface of the air bag cover 18, a groove 36
Similar grooves 36A and 36B are formed at the positions corresponding to A and 36B, but as shown in FIG. 1A, the groove is formed at the portion corresponding to one curved portion of the loop-shaped portion of the groove 36A. Are not formed (structure similar to that described in FIG. 10).

As a result, the air bag cover 18 has grooves 36 on both front and back surfaces.
A, 36B is locally thinned to form a rupturable easy portion that can be easily ruptured, and the rupturable easy portion of the portion formed by the groove 36A has a curved central portion extending linearly. There is.

The air bag cover 18 is made of a synthetic resin foam having a skin, and two mesh cloths 38 are embedded in the inside by insert molding as shown in FIGS. 1 and 1A. The ends of the mesh cloths 38 along the easy-to-break portion of the portion formed by the groove 36A face each other by being cut into an uneven shape so as to substantially follow the curved shape of the easily-breakable portion. This mesh woven fabric 38 has a general plain weave design as shown in FIG. 4, and in this embodiment, the warp yarn 38A and the weft yarn 38B are made of nylon yarn having a thickness of 1680 denier.
Both use about 9 yarns / inch, and when weaving with a width of 116 mm, for example, the number of warp yarns is 41 / width, which is a fairly coarse design.

The material of the mesh woven fabric 38 has ears 38C woven at both ends in the width direction as shown in FIG. As described above, a part of the ear portion 38C is cut off by cutting the end portion into a concavo-convex shape, and the remaining portion is a groove as shown by hatching in FIG.
It is arranged along the breakable portion of the portion formed by 36A. The other ears 38C are located at the lower end of the air bag cover 18 and overlap the insert plate 40.

Next, the operation of this embodiment will be described.

When a vehicle equipped with the air bag device 10 is significantly decelerated while traveling, the inflator 20 inflates the air bag bag body 16 by the generated gas. The air bag bag body 16 starts to expand and presses the air bag cover 18 from the inside.
When the air bag cover 18 is pressed, the easy-breaking portion of the groove 36A is first broken, then the groove 36B is broken and the air bag bag 16 is advanced toward the occupant by opening to the double door. The advanced air bag bag body 16 is deployed between the steering wheel 12 and the occupant.

In this embodiment, the air bag cover 18 has both ends A and B of the groove 36A due to the folded structure of the air bag bag 16.
The fracture starts at (see FIG. 1). In this portion, the ear portion 38C where the warp 38A is not easily frayed is located on one side of the groove 36A, and the tear resistance is large in the adjacent portion of this portion,
Due to the property of load propagation, the rupture progresses so as to be guided to the portion having the high tear strength.

The break that progresses toward the central portion C (see FIG. 1) of the groove 36A passes through the portions where the ears 38C are not located on both sides of the adjacent portion, but both ends are adjacent to the central portion C of the groove 36A. Since a portion having a high tear strength is formed similarly to the adjacent portions of the portions A and B, the portion where the ear portion 38C is not located is oriented so as to connect the portions having a high tear resistance, and the breakage proceeds, A large load does not propagate in the direction intersecting the groove 36A.

At the central portion C of the groove 36A, as in the case of both end portions A and B, the rupture progresses so as to be guided to the adjacent portion having high tear resistance.

Therefore, the portion adjacent to the groove 36A is torn,
It is prevented with an extremely high probability.

Note that, even when the air bag bag body 16 is folded so that the intermediate portion C of the groove 36A starts to break, the operation is the same as that described above.

In this embodiment, the mesh woven fabric 38 having the ears 38C at both ends is embedded, but the ears 38C may be provided only at one end portion along the groove 36A of the portion that constitutes the easily breakable portion.

Also, as shown in FIG. 6, only the ears 38C are warped 38A.
The tear resistance can be further increased by using the mesh woven fabric 38 woven so as to be dense. As an example, if there are 8 warps 38A per 6 mm width of the ears 38C, 33.9
It becomes a book / inch and the structure is about 3.8 times denser than other parts.
The dimensions in the figure are the width dimension A = 116 mm and the ear portion dimension B = 6 mm.

Further, as shown in FIG. 6, if the warp yarn 38A is entangled, even a coarse design with a small amount of the warp yarn 38A can be carried easily without fraying. As an example of a leno weave, tangle weave is performed with two 840 denier nylon threads.

[Effects of the Invention] As described above, in the air bag cover according to the present invention, the tear resistance against tear is obtained by arranging the ears of the mesh cloth at the end of the mesh cloth located along the easily breakable portion. Since a large portion is formed and the fracture is guided by this portion so that the fracture progresses, there is an effect that it is possible to improve the reliability that only the easy fracture portion fractures.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of an embodiment of an air bag cover according to the present invention, FIG. 1A is a sectional view taken along the line IA-IA of FIG.
FIG. 2 is a sectional view showing the air bag device having the air bag cover of the embodiment assembled to a steering wheel, FIG. 3 is an exploded perspective view of the air bag device of FIG. 2, and FIG. A partially enlarged plan view of the mesh woven cloth insert-molded on the air bag cover, and FIG. 5 is an enlarged plan view showing an enlarged part of both ends of the mesh woven cloth insert-molded on the air bag cover of the embodiment. FIG. 6 is a plan view showing another example of mesh cloth, FIG. 7 is a perspective view showing a conventionally considered air bag cover cut at a central portion, and FIG. 8 is an air bag shown in FIG. FIG. 10 is a perspective view showing the woven fabric embedded in the cover in an embedded state, FIG. 9 is a plan view showing a problem occurring in the air bag cover of FIG.
FIG. 11 is a perspective view showing an air bag cover in which a breakable portion having a shape different from that of FIG. 7 is cut at a central portion, and FIG. 11 is a portion showing a woven cloth embedded in the air bag cover of FIG. A plan view and FIG. 12 are plan explanatory views showing a problem that occurs in the air bag cover of FIG. 10 …… Air bag device, 16 …… Air bag bag, 18 ……
Air bag cover, 36A, 36B ... Groove, 38 ... Mesh cloth, 38C ... Ear.

Claims (2)

[Scope of utility model registration request] 1. An easy-to-break rupture portion in which an end portion having a concave portion formed at an intermediate portion of a linear portion and an end portion having a convex portion located in the concave portion formed at an intermediate portion of the linear portion extend linearly. A pair of mesh woven fabrics are embedded at opposite positions on both sides, and the air bag bag is pushed by the inflating air bag bag from the inside and ruptures at the breakable part, and the air bag bag is advanced from the opening formed by this rupture. In the cover, an air bag cover characterized in that an edge portion of the mesh woven cloth is located at an end portion of the mesh woven cloth located along the easily breakable portion. 2. The air bag cover according to claim 1, wherein the mesh woven cloth has warps woven more densely in the selvage than in the middle.