JPH054233A - Method for molding module cover of air bag device - Google Patents

Abstract

PURPOSE:To demold a module cover without deforming the same in the molding of the module cover of an air bag device. CONSTITUTION:Upper and lower molds 16, 11 are clamped and a resin material is injected in the molds to mold a module cover 1. At the time of demolding after molding, the upper mold 16 is raised and lateral molds 13, 14 are raised along the mating surfaces with a central mold 12. After the lateral molds 13, 14 are raised along with the module cover 1, the lateral molds 13, 14 are moved toward the center part. By this constitution, the undercut part 1C of the module cover 1 does not come into contact with the lateral molds 13, 14 and the module cover 1 can be demolded from the lateral molds 13, 14 without being deformed. Therefore, the module cover can be easily and efficiently prepared without bringing about the deformation of a product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a cover for accommodating an airbag device which is inflated and expanded by sensing the impact, deformation and the like when a vehicle collides.

[0002]

2. Description of the Related Art As is well known, an air bag device has an air bag that is rapidly deployed in an emergency such as a vehicle collision. As shown in FIG. 16, in normal times, the airbag 2 is folded and covered with the module cover 1. The airbag 2 is held together with an inflator 4 on a mounting plate 3 called a retainer, and the module cover 1 is also fixed to the mounting plate 3 with rivets 5, screws and bolts.

As shown in FIG. 17, this airbag apparatus is mainly attached to the central portion of the steering wheel 10. 1
0A is a spoke of the steering wheel 10.

The module cover 1 is generally made by single layer molding of rim urethane. However, recently, a two-layer molded product composed of a hard layer (core layer) 1a and a soft layer (skin layer) 1b has also been made. The module cover 1 shown in FIG. 16 is formed by two-layer molding. The module cover 1 is provided with a tear groove-shaped tearing start line for tearing the cover when the airbag 2 is deployed, that is, a tear line 1A. The tear line 1A is a portion having lower strength than the surrounding portion and is provided as a thin portion having a predetermined shape (generally, a thickness of about 0.5 to 1.0 mm). The module cover 1 is split along the tear line 1A.

In FIG. 16, 1B is a makeup line. 6 is a body cover.

Conventionally, as a module cover material for such an airbag, urethane foam integral skin foam or thermoplastic is generally used.
These resin materials are poured into a mold having a predetermined shape to be molded.

[0007]

When a module cover of such an airbag device is manufactured from synthetic resin, if the module cover has an undercut portion, an excessive force is applied to the product when the mold is released, and the product is deformed. Easy to make.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide a method of molding a module cover of an airbag device, which can be removed from a mold without deforming the module cover.

[0009]

A method of molding a module cover of an air bag device according to the present invention is a method of molding a module cover of an air bag device, wherein the mounting base end side of the module cover has an undercut shape. In the molding method of the module cover, the mold arranged on the inner surface side of the module cover has a plurality of molds including a central mold on the center side of the module cover and a lateral mold for forming an undercut portion. It is composed of split molds, and the mating surface of the central mold and the lateral molds is an inclined surface that approaches the side of the module cover toward the base end side, and the molds can be demolded by moving toward the central direction of the lateral molds. Is characterized by.

[0010]

When the side mold is moved toward the center along the mating surface, the side mold can be demolded so as to bypass the undercut.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 10 are views for explaining the method of the embodiment of the present invention. FIG. 1 is a plan view of a module cover to be molded, and FIG. 2 is along line II-II in FIG. Sectional view, FIG. 3 is a sectional view taken along line III-III in FIG. 1, FIG. 4 is a plan view of a mold, FIG. 5 is sectional view taken along line VV in FIG. 4, and FIG.
The drawing is a sectional view taken along the line VI-VI in FIG. 4, and FIGS. 7 to 10 are sectional views showing the demolding procedure.

In this embodiment, as shown in FIGS. 1 to 3, a module cover 1 having an undercut portion 1C at a pair of facing ends is formed. As shown in FIGS. 4 to 6, among the molds used in this embodiment, the lower mold 11
Is a central mold 12 for molding the central part of the hollow part of the module cover 1, a first lateral mold 13 and a second lateral mold 14 for molding an undercut part on the lateral part of the hollow part,
It is composed of a frame-shaped mold 15 for molding the peripheral portion, and the central mold 12 and the frame-shaped mold 15 are integrated. The mating surfaces of the central mold 12 and the first lateral mold 13 and the second lateral mold 14 are inclined surfaces whose base ends approach the lateral sides of the module cover 1. In addition, the frame-shaped mold 15 and the first
The mating surfaces of the side mold 13 and the second side mold 14 are substantially vertical. In addition, 16 is an upper mold.

In this embodiment, first, as shown in FIGS. 5 and 6, the upper mold 16 and the lower mold 11 are tightened and a resin material is injected to mold the module cover 1. When removing the mold after molding, the upper mold 16 is raised as shown in FIGS. 7 and 8. Then, as shown in FIGS. 9 and 10, the first lateral mold 13 and the second lateral mold 14 are raised along the mating surface with the central mold 12. During this ascent, the central mold 12, the first lateral mold 13, and the second lateral mold 1
As for the mating surface with 4, the base end side is the module cover 1
Of the frame-shaped die 15, the first lateral die 13 and the second lateral die 14 are substantially vertical, so that no force is applied to the module cover 1. The first lateral mold 13 and the second lateral mold 14 easily without adding
Can be raised. First lateral mold 13 and second
After raising the side mold 14 together with the module cover 1, the side mold 13 and the side mold 14 are moved to the center side (9th embodiment).
Arrow A). As a result, the undercut portion 1C of the module cover 1 and the side molds 13 and 14 do not come into contact with each other, and the side molds 13 and 14 can be removed from the mold without deforming the module cover 1.

In this embodiment, the module cover 1
Together with raising the side molds 13 and 14, and then the side molds 1
Although the molds 3 and 14 are moved toward each other in the approaching direction, even if the side molds 13 and 14 are moved toward each other while raising the module cover 1 and the side molds 13 and 14. good. Also, it goes without saying that the center mold 12 may be lowered instead of raising the side molds 13 and 14, and "raise" means a relative rise.

FIGS. 11 to 15 are views for explaining a method of another embodiment of the present invention. FIG. 11 is a plan view of a mold,
12 is a sectional view taken along the line XII-XII in FIG. 11, and FIG.
11 is a sectional view taken along the line XIII-XIII in FIG. 11, and FIGS. 14 and 15 are sectional views showing the demolding procedure.

The method of this embodiment is an embodiment of a method of molding a module cover having undercut portions on all ends. As shown in FIGS. 11 to 13, among the molds used in this embodiment, the lower mold 21 is a central mold 22 for molding the central part of the hollow part of the module cover, and an undercut on the side part of the hollow part. A first lateral mold 23, a second lateral mold 24, a third lateral mold 25, a fourth lateral mold 26 for molding a portion, and a frame-shaped mold 27 for molding a peripheral portion. The central mold 22 and the frame-shaped mold 27 are integrated with each other. The mating surfaces of the central mold 22 and the first to fourth lateral molds 23 to 26 are inclined surfaces whose proximal ends approach the sides of the module cover (not shown). Further, the mating surfaces of the frame-shaped die 27 and the first to fourth lateral dies 23 to 26 are substantially vertical.

In the method of this embodiment, the upper die (not shown) and the lower die 21 are fastened to each other and the resin material is injected to mold the module cover (not shown). And, as shown in FIG. 13, the upper die (not shown) is raised. Thereafter, as shown in FIGS. 14 and 15, the central mold 22 integrated with the frame-shaped mold 27 is lowered.
During this descent, the central mold 22 and the first to fourth lateral molds 2
The mating surfaces with 3 to 26 are inclined surfaces with their base ends approaching the sides of the module cover, respectively.
Since the mating surfaces with the fourth lateral molds 23 to 26 are substantially vertical, the central mold 22 (and the frame mold 27) can be easily lowered without applying any force to the module cover. ..

After the central mold 22 is lowered, the first lateral mold 23 and the second lateral mold 24 are moved toward the central side (arrow A in FIG. 15), and the third lateral mold is also moved. 25 and the fourth lateral mold 26 are also moved to the center side (arrow A in FIG. 14) to prevent the undercut portion of the module cover from contacting the lateral molds 23 to 26, and then the lateral mold 23. Also lower ~ 26. As a result, it is possible to remove the mold without deforming the module cover.

In the method of this embodiment, the central mold 2 is also used.
The side molds 23 to 26 may be moved to the center side while lowering 2. Also, instead of lowering the central mold 22, the lateral mold 2
You may raise 3 to 26.

1 to 10 relate to the molding method of the module cover 1 by the two-color molding method. This 2
In the case of the color molding method, first, as shown in FIG. 18, the core layer 1a is formed by using the upper mold 160 having a cavity which is slightly smaller than the upper mold 16 (that is, by the thickness of the skin layer 1b).
Then, the skin layer 1b is formed on the front side of the core layer 1a as shown in FIGS. 5 to 10, and the module cover 1 is manufactured.

The present invention can be applied not only to the two-color molding method and the multi-color molding method of three or more colors but also to the module cover manufacturing method by the one-color molding method.

FIG. 19 is a sectional view showing a state where the module cover 1 is manufactured by the one-color molding method, and shows a state corresponding to FIG. According to the one-color molding method, a module cover having a single phase in which the core layer and the skin layer are not distinguished from each other is molded.

The method described above is an embodiment of the present invention, and the present invention is not limited to the illustrated method. For example, various aspects can be adopted within the range not exceeding the gist of the present invention, such as the method of dividing the lower mold, the shape, and the degree of inclination of the mating surfaces of the central mold and the lateral mold. Further, the mating surface of the side mold and the frame mold may be an inclined surface.

[0025]

As described in detail above, according to the method of molding the module cover of the airbag device of the present invention, when molding the module cover having the undercut portion, it is possible to apply an unreasonable force to the product module cover. The module cover can be removed from the mold, and the module cover can be easily and efficiently manufactured without causing deformation of the product.

[Brief description of drawings]

FIG. 1 is a view for explaining an embodiment method of the present invention, and is a plan view of a module cover to be molded.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a plan view of a mold.

FIG. 5 is a sectional view taken along line VV in FIG.

FIG. 6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a cross-sectional view showing a demolding procedure.

FIG. 8 is a cross-sectional view showing a demolding procedure.

FIG. 9 is a sectional view showing a demolding procedure.

FIG. 10 is a cross-sectional view showing a demolding procedure.

FIG. 11 is a plan view of a mold for explaining a method of another embodiment of the present invention.

FIG. 12 is a sectional view taken along the line XII-XII in FIG. 11.

13 is a sectional view taken along the line XIII-XIII in FIG.

FIG. 14 is a cross-sectional view showing a demolding procedure.

FIG. 15 is a cross-sectional view showing a demolding procedure.

FIG. 16 is a cross-sectional view of the airbag device.

FIG. 17 is a perspective view showing a mounted state of the airbag device.

FIG. 18 is a cross-sectional view illustrating a two-color molding method.

FIG. 19 is a cross-sectional view illustrating a one-color molding method.

[Explanation of symbols]

 1 Module Cover 1C Undercut Part 2 Airbag 4 Inflator 10 Steering 11, 21 Lower Mold 12, 22 Central Mold 13, 14, 23, 24, 25, 26 Side Mold 15, 27 Frame Mold 16, 160 Upper Mold

Claims (1)

Claim: What is claimed is: 1. A method for molding a module cover of an airbag device, wherein a mounting base end side of the module cover has an undercut shape. The mold to be arranged on the inner surface side of is composed of a plurality of split molds having a central mold on the central side of the module cover and a lateral mold for forming an undercut portion, and the central mold and the side mold. The module cover of the airbag device is characterized in that the mating surface with the rectangular shape is an inclined surface that is closer to the side of the module cover toward the base end side, and the side mold is decentered toward the center to enable demolding. Molding method.