JP2006036149A - Airbag cover, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag cover which has a U-shaped or H-shaped fracture planned part suitable for integrating an instrument panel having a flexible decorative surface layer provided on a base material layer, and is reliably broken along the U-shaped or H-shaped fracture planned line when an airbag device is operated. <P>SOLUTION: The airbag cover has a hard resin-made base material layer and a flexible resin-made surface layer which is laminated on the base material layer. A break scheduling part comprises a U-shaped or H-shaped longitudinal break scheduling part to form a side edge orthogonal to a hinge part when broken and a transverse break scheduling part parallel to the hinge part. In the longitudinal direction, the airbag cover consists of a bottomed groove formed in the base material layer, a projection directed to the surface layer provided on a part corresponding to the surface layer side, and a raised part along a wall part of the groove in the surface layer corresponding to the groove. In the transverse direction, the airbag cover consists of a bottomed groove formed in the base material layer, and a projection directed to the surface layer provided on the part corresponding to the surface layer side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an airbag cover and a manufacturing method thereof.

The airbag device senses an impact when the automobile receives an impact, inflates and deploys the airbag, and interposes between the vehicle body and the occupant, thereby protecting the occupant.
In recent years, it has become widespread, and in addition to the steering wheel for the driver's seat and the instrument panel for the passenger's seat, a side airbag that protects the passengers from the impact on the side is located on the upper part of the vehicle side window. It came to be arranged.
Among these, in the airbag device for the passenger seat that is arranged inside the instrument panel, an airbag cover that covers it is prepared separately from the instrument panel, and this is provided on the instrument panel. In recent years, there has been a desire to streamline manufacturing and assembly operations by integrating them into modules, and to improve the appearance of instrument panels as interior parts. Has been.

And what integrated the airbag cover body in the instrument panel in this way has already been proposed, for example, what is indicated in JP, 11-29069, A (patent documents 1) uses an instrument panel for an airbag. Injection molding is performed without providing an opening, and laser processing is performed at a location corresponding to the airbag storage position on the back of the panel to form a planned fracture line.
In addition, there has also been proposed a molding method in which a planned fracture line is formed at the time of molding without post-processing the planned fracture line for deploying the airbag cover body after panel formation (Japanese Patent Laid-Open No. 2002-2002). 234413, Patent Document 2).

However, the former method of post-processing the expected fracture line requires a laser processing machine for this purpose, and also has a problem from the viewpoint of productivity, such as requiring subtle processing operations after molding. .
In addition, the latter molding method is a rational method in that no post-processing is required, but it is necessary to provide a core for forming a planned fracture line in the molding die so that it can be moved forward and backward. It becomes complicated and the molding method becomes complicated.

In addition, since the instrument panel is an interior part, its appearance and touch are also important. Therefore, various types of two-layer structures in which the surface layer of the panel is made of a soft and soft material and laminated on the base material layer have been proposed.
However, in the case of such a two-layer structure, it is technically difficult to stably obtain a predetermined breaking property. That is, the present inventor has found out from various trial results based on the teachings of the prior art that technical means for stably causing the skin layer to rupture directly above the groove provided in the base material layer. We have the knowledge that it is necessary. This is because the airbag cover is not necessarily pushed up uniformly from the lower airbag, and it is easy to break in a direction inclined with respect to the upward direction by applying a shearing force due to a stepped uplift. Presumed. For example, in the case of a single flap type (single-opening type) cover, the relationship between the door forming portion and the periphery thereof, and in the case of a twin flap type (double-opening type) cover, there is a relationship in which the adjacent flaps are pushed up unevenly. is there. This breaking angle can be either a direction directly above or a similar direction, and the angle when tilting is not likely to be constant. Therefore, selection of a material for obtaining desired fracture characteristics, specification of molding processing conditions that can stably use physical properties of the specific material, and strict quality control are required, and there is a concern about a significant increase in cost.

In such an airbag cover having a two-layer structure, proposals have also been made to reliably break the planned break line with a smaller force. That is, in Japanese translations of PCT publication No. 2000-512953 (Patent Document 3), the cover body does not continue to break beyond the end of the intended breaking line on the cover body of the airbag having a smooth surface cover layer. Has been proposed for a two-layer airbag cover body that can be broken by a smaller force and that can change the opening force and breaking force without changing the visual and / or mechanical properties.
According to this, in the groove part of a base material layer, it is supposed that a fracture line will be formed in the edge between the part where a surface layer and a base material layer extend in each other layer.
With such a configuration, the two-layer contact surfaces are ruptured, and it is considered that the rupture as designed along the planned rupture line can be more reliably performed.
JP-A-11-291069 JP2002-234413 Special table 2000-512953

However, although the problems related to the fracture characteristics of the two-layer structure have already been described, in the case where the portion to be fractured is a U-shape or H-shape, in addition to the above-mentioned problems, a U-shape or H-shape longitudinal fracture There is also a problem that the easiness of breakage differs between the planned portion and the planned transverse breakage portion (as viewed from the passenger side). In general, the longitudinally fractured portion is less likely to break than the laterally fractured portion. However, a situation in which the airbag is inflated in a state in which the longitudinally scheduled breaking portion that is difficult to break is not sufficiently opened must be avoided because it may hinder predetermined deployment of the airbag.
However, in Patent Document 3, such a problem recognition is not seen.

Under such circumstances, the present invention is an airbag cover having a U-shaped or H-shaped breakable portion suitable for instrument panel integration in which a soft decorative surface layer is provided on a base material layer, An object of the present invention is to provide a highly reliable airbag cover as a safety device that can be reliably broken along the U-shaped or H-shaped planned break line during operation of the airbag device.
Moreover, an object of this invention is to provide the manufacturing method of the airbag cover suitable for such instrument panel integration.

  As a result of diligent study, the present inventor, as an air bag cover suitable for instrument panel integration having a structure in which a soft surface layer is provided on a base material layer, has a U-shaped or H-shaped rupture scheduled portion. In addition, a bottomed groove is provided on the base material layer side in the portion in the longitudinal direction that is relatively difficult to break, and a protrusion toward the surface layer is provided in the surface layer side corresponding portion, and along the wall portion of the groove Forming a raised portion from the surface layer side, and providing a bottomed groove on the base material layer side in a portion that is likely to break relatively easily in the lateral direction, and a protrusion toward the surface layer in the corresponding portion on the surface layer side It is found that the provision of the above is effective in balancing the ease of rupture of both planned rupture portions and wiping out the concern that the above-mentioned vertical rupture portion will bulge in an insufficiently ruptured state. The present invention has been achieved.

That is, the present invention
(1) An airbag cover provided with a U-shaped or H-shaped rupture-predicting portion that covers the airbag inflating direction of an airbag device incorporating a stored airbag and forms a door portion by deployment of the airbag. A hard resin base layer disposed on the air bag device side, and a soft resin surface layer laminated on the base layer, and the U-shaped or H-shaped portion to be broken is broken From a U-shaped or H-shaped longitudinally-scheduled part that will form a side edge in a direction perpendicular to the hinge part and a U-shaped part or H-shaped laterally-scheduled part that is parallel to the hinge part. The longitudinally-scheduled portion is a bottomed groove provided on the side facing the airbag device of the base material layer, a protrusion directed to the surface layer provided on the surface layer side corresponding portion, and a surface layer corresponding to the groove Consists of ridges along the wall of the groove. The air bag cover is characterized by comprising a bottomed groove provided on the side opposite to the airbag device of the base material layer and a projection directed to the surface layer provided on the surface layer side corresponding portion as the laterally broken portion .
(2) The airbag cover according to (1), wherein the raised portion is formed outside the groove portion.
(3) The airbag cover according to the above (1) or (2), which is integrated with an instrument panel.
(4) The method for manufacturing an instrument panel-integrated airbag cover according to (3), wherein an inner member having a wall portion provided with a locking portion for locking the airbag device is coupled in advance. Placing the insert material made of the base material on one mold, and placing the insert material so as to surely form a thin cavity having a predetermined interval between the protrusion of the base material and the other mold; A method of manufacturing an airbag cover, comprising: a step of drawing the inserted material toward the mold side, a step of closing the other mold, and a step of injecting a resin material for forming a surface layer into the formed cavity.
(5) The airbag cover according to (4), wherein the step of drawing the mold includes drawing the insert material to one mold by engaging a clamp with the engaging portion of the inner member coupled to the insert material. Manufacturing method.
It is about.

  The present invention, as a configuration of the U-shaped or H-shaped break scheduled portion of the instrument panel integrated airbag, provided with a bottomed groove on the base material layer side in the longitudinal break scheduled portion that is relatively difficult to break, The surface layer side corresponding portion is provided with a projection directed to the surface layer, and a raised portion is formed from the surface layer side along the wall portion of the groove. Providing a bottomed groove on the base material layer side, and providing a protrusion toward the surface layer on the surface layer side corresponding part balances the easiness of breakage of both planned breakage parts, This is a case where the fear of the airbag bulging out in an insufficiently broken state is wiped out, and when the airbag device is activated and the airbag pushes up the airbag from below, a shearing force is generated at the planned fracture portion. However, the deviation of the planned fracture position should be suppressed as much as possible. Can be reliably broken the air bag cover in virtually breakable position, it is possible to deploy the air bag.

  Further, according to the airbag manufacturing method of the present invention, the inner member for locking the airbag device is integrated with the base material having a structure in which the projection is provided on the surface layer side in the planned fracture portion, and this is molded into the mold. Inserted into the inner member, and using the engaging portion of the inner member, the engaging member can draw the insert material toward the mold side to ensure a space between the protrusion and the other mold. Therefore, a very thin portion of the surface layer corresponding to the protrusion can be uniformly formed with a predetermined thickness dimension. Therefore, the protrusions do not interfere with the mold at this part, are damaged, or the surface layer is chipped, becomes extremely thin, etc., and the appearance of the predetermined breaking characteristics is not hindered, and the appearance is not impaired. . Further, it is possible to eliminate the possibility that the surface layer around the protrusions is scattered at the time of breaking.

As described above, the airbag cover of the present invention is composed of the base material layer and the surface layer laminated thereon.
The base material layer is preferably made of a PPC resin having a thickness of 2.5 to 4.0 mm and a relatively hard material such as polypropylene reinforced with talc or the like. Moreover, it is preferable that the surface layer laminated | stacked on it is 0.5-3.0 mm in thickness, and is comprised with a soft material, for example, a polyurethane. Of course, you are not limited to these materials. In short, any material may be used as long as the base material layer is harder and can maintain the necessary strength as an airbag cover, and the surface layer is softer, preferably elastic, and improves the surface appearance and touch.

In the airbag cover of the present invention, a U-shaped or H-shaped detailed structure that forms the planned fracture line is important.
That is, in the longitudinally scheduled fracture portion that is relatively difficult to break, a projection is provided on the surface layer side corresponding to the groove portion provided in the base material layer to form a thin portion on the surface layer. The protruding portion of the surface layer is provided outside the groove to make the surface layer thick. In other words, the thin wall portion is provided on the wall of the groove portion of the base material layer. On the other hand, a groove portion is provided in the base material layer in the laterally scheduled break portion that is relatively easy to break, and a projection directed to the surface layer is provided in the corresponding portion on the surface layer side. Although the thin wall portion along the wall of the groove portion does not need to be provided, the thin wall portion can also be provided in order to adjust the easiness of breaking with the longitudinally scheduled break portion.
By adopting such a structure, it is possible to balance the easiness of breakage between the longitudinal direction breakage portion and the transverse direction breakage portion, and the breakage and tearing of the airbag cover due to the inflation of the airbag can be sufficiently achieved as designed. And it can be done smoothly.
In addition, it is preferable to provide the protrusion of the base material layer at the planned lateral fracture portion closer to the passenger side or the window side so as to extend along the extension line to the surface layer of the groove portion than directly above the groove portion of the base material layer. Moreover, it is preferable to provide the protrusion in the longitudinal direction breaking part directly above the groove part.

Hereinafter, the structure of the planned fracture portion will be further described.
First, the groove is a bottomed groove. By forming the bottomed groove, it contributes to the suppression of the stepped bulge when the airbag cover is broken due to the expansion of the airbag, and the molding material for the surface layer is prevented from entering the groove during molding.
Moreover, this groove part is provided in the base material layer from the airbag device side, preferably so as to have a groove remaining thickness of 0.4 to 0.8 mm. When the thick portion of the surface layer is provided outside the groove portion, the surface layer forms the thick portion along the wall portion above the groove, and the surface layer is the portion, preferably 0.5 to 1. It is preferable to form a 5 mm raised portion.
The protrusion preferably has a height of 0.1 to 0.5 mm, and the thickness of the surface layer of this portion is preferably 0.5 to 0.9 mm.
The shape of the surface layer raised portion 7 may be substantially semicircular in cross section or rectangular rib shape, and these may be provided outside or inside the groove portion 5. It may be provided on both sides. However, it is preferable to provide only outside.
Further, the surface layer raised portions may be provided intermittently at appropriate intervals in addition to being provided continuously along the groove portion 5.

By adopting such a structure for the planned breaking line, it is possible to balance the ease of breaking in the vertical and horizontal directions as described above and to prevent the deviation of the planned breaking part. That is, even when a shearing force is applied by pushing up the airbag to be inflated from below when the airbag device is operated, the stress can be concentrated there by the structure of the planned breaking portion. The cover can be reliably deployed.
In addition, since the thin part by a linear protrusion is formed in a surface layer and there exists a possibility of damaging the surface appearance of an airbag cover by the influence, it is preferable to process a wrinkle etc. in a surface layer.
The airbag cover of the present invention is particularly suitable for instrument panel integration, but is not limited thereto.

The airbag cover of the present invention is formed by inserting a base material in which an inner member is integrated in advance into a mold, and after being placed on the mold, the protrusions provided on the base material and the upper mold It draws toward the mold side on which the insert material is placed so as to maintain a predetermined interval therebetween. If this operation is lacking, there are problems such as the protrusions coming into contact with the upper mold and being damaged, the in-mold coating applied to the upper mold being peeled off, or the distance from the upper mold being unable to ensure a predetermined thickness. A thin portion having a predetermined uniform thickness cannot be formed.
Thereafter, the upper die is closed, and then a surface layer can be formed on the insert material by a polyurethane reaction injection molding method.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an exploded perspective view of an airbag cover formed integrally with the instrument panel of the present invention. In FIG. 1, 1 is a polyurethane surface layer, 2 is a PPC resin base material layer, 3 is a TPO resin inner member that supports the air bag device, 4 is an air bag device, and 5 is an air bag device side of the base material layer. 6 is an H-shaped protrusion provided on the surface layer side of the base material layer, and 7 is a recess provided along the outside of the opposing protrusion 6 in the base material layer, corresponding to the raised portion of the surface layer. It is a part. The part to be broken in the vertical direction is composed of the groove part 5, the recessed part 7, and the protrusion 6. Further, the laterally planned fracture portion is constituted by the groove portion 5 and the protrusion 6. However, a concave portion may be formed here in order to adjust the easiness of breaking with the longitudinal direction breaking portion. By providing the groove portion 5 of the base material layer and the concave portion 7 on the outside thereof in the longitudinally planned fracture portion, the groove portion of the base material layer is made thin and easily broken, and the concave portion is made to be a raised portion (thick wall) of the surface layer. Part), and the portion immediately above the groove portion is protruded into the surface layer to make it thin, so that stress concentration occurs in the portion immediately above the groove portion and can be surely broken. Further, in the lateral direction, which is easier to break than in the longitudinal direction, stress can be concentrated in the groove portion 5 without being provided with a recess, and the break can be smoothly broken along the protrusion 6. Thus, the protrusion contributes to making the H-shaped break more reliable. In FIG. 1, 9 is a wall portion provided with a locking portion 10 for locking the airbag device.

  FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and the airbag device is supported by the locking portion (hole) of the inner member. In FIG. 2, reference numeral 11 denotes a groove portion that forms a hinge portion when the airbag cover is broken or opened. FIG. 3 is a cross-sectional view taken along the line BB in FIG. 1, which shows the structure of the portion scheduled to be broken in the longitudinal direction. Due to the structure of the fracture portion, as already described, the bottom of the groove portion 5 protrudes toward the surface layer side to form a projection, so that the surface layer becomes very thin at that portion, while the outside of the projection is When the airbag is pushed up by stress concentration on the upper portion of the thin groove portion of the surface layer due to the relationship with the raised portion (thick portion) of the surface layer corresponding to the concave portion 7 of the base material layer formed in It can be reliably broken at a position immediately above 5. FIG. 4 is an explanatory diagram of a portion planned to be broken in the lateral direction including the groove 5 and the protrusion 6 shown in FIG. Due to the structure of the broken portion, that is, the stress is concentrated at the bottom of the groove portion 5 of the base material layer, the surface layer breaks, and at the interface between the two layers along the protrusion 6 protruding from the base material layer to the surface layer. Breaking progresses. In this way, predetermined breaking and tearing can be realized in an H shape. In addition, FIG. 9 is explanatory drawing of the state which the H-shaped fracture | rupture planned part broke.

5 to 8 are views for explaining the method of forming the airbag cover of the present invention, and are explanatory views in the mold in the same cross-sectional direction as FIG. FIG. 5 is an explanatory view showing a state in which an insert material in which the inner member 3 is previously bonded to the back surface of the base material 2 by vibration welding or the like is placed on a mold (lower mold). FIG. It is explanatory drawing of the state which utilized the airbag apparatus latching | locking part (hole) of the inner member 3, engaged the clamp 13 there, and pulled the insert material to the metal mold | die side, and was positioned. The clamp has one locking portion (hole) located in the substantially central portion on the windshield side provided on the longitudinal wall of the inner member, and two locking portions (holes) located on both ends on the passenger side. It is preferable to be located at.
FIGS. 7 and 8 are diagrams illustrating an example in which the insert material is drawn to the mold side by another mechanism and an actuator is used. FIG. 7 is an explanatory view of the state before clamping, and FIG. 8 is an explanatory view of the state after clamping.

  After positioning the insert material in the mold in this way, the upper mold is closed to form a cavity for the surface layer. Since the insert material is drawn and positioned to the lower mold before the mold is closed, the projection provided on the base material layer does not contact the upper mold when the mold is closed, and the predetermined interval can be reliably maintained. . The polyurethane reaction molding material can then be injected to mold the airbag cover of the present invention.

The disassembled perspective view of the airbag cover shape | molded integrally in the instrument panel of this invention. FIG. 1A AA sectional view. 1B-B line sectional view. Explanatory drawing of the transverse direction fracture plan part which consists of the groove part 5 and the protrusion 6 shown in FIG. Explanatory drawing of the state which mounted the insert material in the metal mold | die with explanatory drawing of the shaping | molding method of this invention. Explanatory drawing of the state which attracted and positioned the insert material to the metal mold | die side with explanatory drawing of the shaping | molding method of this invention. Explanatory drawing before clamp in the case of using an actuator with explanatory drawing of a shaping | molding method same as the above. Explanatory drawing after clamp same as the above. It is explanatory drawing of the state which the H-shaped fracture | rupture scheduled part was cleaved.

Explanation of symbols

1: Surface layer 2: Base material layer 3: Inner member 4: Air bag device 5: Groove 6: Protrusion 7: Recessed portion provided in the base material layer 8: H-shaped fracture scheduled portion provided on the back side of the surface layer 9: Wall part 10 of inner member: Hole for supporting airbag device provided in wall part 11: Hinge part 12: Cylinder for clamping 13: Clamp

Claims (5)

An airbag cover having a U-shaped or H-shaped rupture-predicting portion that covers the airbag inflating direction of an airbag device incorporating a stored airbag and forms a door portion by deployment of the airbag. It has a hard resin base layer placed on the device side and a soft resin surface layer laminated on the base layer. It consists of a U-shaped or H-shaped longitudinally scheduled fracture portion and a U-shaped in the direction parallel to the hinge portion or an H-shaped laterally fractured portion that will form a side edge perpendicular to the vertical direction. As the direction-breaking portion, the bottomed groove provided on the side opposite to the airbag device of the base material layer, the protrusion directed to the surface layer provided on the surface layer side corresponding portion, and the groove on the surface layer corresponding to the groove Consists of ridges along the wall and sideways A bottomed groove formed in the airbag apparatus opposite the side of the substrate layer as a countercurrent breakable portion, the airbag cover, characterized in that consisted projection towards the surface layer provided on the surface layer side corresponding portion. The airbag cover according to claim 1, wherein the raised portion is formed outside the groove portion. The airbag cover according to claim 1 or 2, wherein the airbag cover is integrated with the instrument panel. A method for manufacturing an instrument panel integrated airbag cover according to claim 3, wherein the inner member having a wall portion provided with a locking portion for locking the airbag device is joined in advance. A step of placing the insert material on one mold, and an insert material placed so as to reliably form a thin cavity having a predetermined interval between the protrusion of the base material and the other mold. A method for manufacturing an airbag cover, comprising: a step of drawing toward a mold side; a step of closing the other mold; and a step of injecting a resin material for forming a surface layer into a formed cavity. 5. The method of manufacturing an airbag cover according to claim 4, wherein the step of drawing the mold comprises drawing the insert material to one mold by engaging a clamp with the locking portion of the inner member coupled to the insert material. .

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