JPH04365652A - Pad of air bag equipment - Google Patents

Abstract

PURPOSE:To provide the pad of an air bag equipment, the freedom of whose design is increased and the structure of whose molding die becomes simple, as the result of such design that the groove for forming a thin section part is not formed outside. CONSTITUTION:The special feature of this pad is that a soft polyurethane material is prescribed so as not to foam, as well as the groove 11b for forming a thin section part is formed only inside, regarding the pads 1, 1A which are equipped to an air bag equipment and molded of the soft polyurethane material and provide the groove for forming the thin section part.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is mounted on an airbag device and is molded from semi-rigid polyurethane (PUR) material.
The present invention relates to a pad having a groove for forming a broken portion.

[0002] In this specification, the compounding unit is a weight unit unless otherwise specified.

0003

2. Description of the Related Art FIGS. 2 and 3 show an example of a pad for a conventional air bag device.

The pad 1 of the airbag device is a box-like body with a downward opening and consisting of a rectangular upper wall portion 2 and a peripheral wall portion 3, and a holder 4 is integrated at the lower end of the box-like body. Note that the upper wall portion 2 is formed to be slightly curved upward.

This pad 1 is attached to an inflator 7 to which an airbag 6 disposed above a boss 5 is assembled.
It is fixed and assembled by bolting or the like via the holder 4.

[0006] The upper wall portion 2 is provided with a substantially H-shaped thinned portion 11 so that it can be easily broken when the airbag is expanded.
are formed, and expanded portions 12 are formed at the upper and lower portions of the H-shape. Note that in the illustrated example, 8 is a lower cover.

[0007] The pads are then reaction injection molded (RIM), typically using a semi-rigid PUR material with a Freon foam formulation.
Shape. At this time, a PUR molded product with a Freon foaming formulation has a large molded product shrinkage rate, and shrinkage easily occurs on the surface. In order to hide this shrinkage, it is necessary to provide the broken bottom wall forming grooves 11a and 11b, which form the broken bottom wall portion 11, on the front side as well as on the back side.

[0008]

[Problems to be Solved by the Invention] However, providing a groove for forming a broken portion on the front side as well as the back side for concealing shrinkage limits the degree of freedom in the design of the pad and requires a complicated mold. This is undesirable.

[0009] In view of the above, an object of the present invention is to provide an airbag device in which the degree of freedom in the design of the pad is increased and the mold structure is simplified as a result of not forming grooves for forming the thin part on the surface side. Our goal is to provide you with pads.

0010

[Means for Solving the Problems] A pad for an airbag device according to the present invention solves the above problems by the following structure.

[0011] Semi-rigid PUR is attached to the airbag device.
The pad is molded from a material and has a groove for forming a broken bottom part, characterized in that the semi-rigid PUR material has a non-foaming formulation, and the groove for forming a broken bottom part is formed only on the back side. do.

0012

Embodiments Next, embodiments of the present invention will be explained based on the drawings. The same parts as those in the conventional example are given the same reference numerals and their explanation will be omitted.

(i) The basic configuration is the same as the conventional example. That is, the pad 1A of the airbag device is a box-like body with a downward opening, consisting of a rectangular upper wall part 2 and a peripheral wall part 3, and a holder 4 is integrated at the lower end of the box-like body. Note that the upper wall portion 2 is formed to be slightly curved upward.

(ii) This pad 1A has a conventional structure, and is molded from a semi-rigid PUR material with a non-foaming formulation, and the fractured wall portion forming groove 11b is formed only on the back side.

(2) By making the semi-rigid PUR material into a non-foaming formulation, the shrinkage rate is significantly lower, as shown in the test examples described below. Therefore, there is no possibility that "shrinkage" will occur on the pad surface. Note that even non-foaming formulations can be made into foam by blowing air.

The semi-rigid PUR material used here is assumed to have a hardness of Shore A of 50 to 90. Specifically, it is possible to use a general-purpose material in which the polyol component is a polyether type, and the polyisocyanate component is an MDI type. The specific formulation and molding conditions are shown below.

[0017] PUR material formulation (non-foaming formulation)
<First liquid> Mixed polyether polyol

(OH value: 150) Polyamine Ethylene glycol (crosslinking agent) Dibutyltin diurarate (catalyst) Total of the above 10
0 parts brown pigment
3
Part <Second liquid> MDI polymer (NCO content: 24%)
49 parts RIM molding conditions PUR material temperature (first liquid/second liquid): 35°C, injection pressure: 150 kgf/cm2 (15 MPa), mold temperature:
60℃, injection amount: 220g/s.

[0018]

[Operations and Effects of the Invention] The pad of the airbag device of the present invention is injection molded from a semi-rigid PUR material with a non-foaming formulation, so that no shrinkage appears on the surface side of the portion where the broken wall portion is formed. Therefore, it is not necessary to form a groove for forming a thin portion on the surface side to conceal the shrinkage of the surface of the molded product. Therefore, as a result of not forming a groove for forming a thin portion on the surface side, the degree of freedom in designing the pad is increased, and the mold structure is also simplified.

[0019]

[Test Example] Tests conducted to prove the action and effects of the present invention will be explained.

(i) Examples are PUR of the above-mentioned formulation.
A test piece (400×400×
3mmt) was subjected to RIM molding. In addition, the comparative example was molded under the following conditions using a PUR material with the following formulation. In addition, the test piece had a fracture bottom wall forming groove (width 2 x depth 2 mm) formed on the back side.

The test results are shown in Table 1. In the comparative example, the shrinkage rate was large and noticeable shrinkage occurred, whereas in the example,
Table 1 shows that the shrinkage rate was small and almost no visible shrinkage occurred.

Foaming recipe PUR material formulation <First liquid> Polyether polyol
50 parts (Number of functional groups: 2, molecular weight: 4000) Polyether polyol
50 parts (average number of functional groups: 3, molecular weight: 5100) Triethylenediamine
0.7 parts
diethylene glycol
17.5 parts anti-aging agent
Part 3 Freon 1
1
16 parts Brown pigment

6 parts <Second liquid> MDI polymer (NCO content: 28%)
49 parts RIM molding conditions PUR material temperature (first liquid/second liquid): 30±2°C, injection pressure: 130 kgf/cm2 (12.7 MPa), mold temperature: 50°C, injection amount: 150 g/s. (ii) Each of the test pieces described above was tested for each of the following items.

[0023] Density: Density was carried out by the underwater displacement method specified in JIS K 6301.

■Hardness: Measured according to ASTM K 6301.

■Tensile strength: Tested according to JIS K 6301.

[0026]Shrinkage: The state of shrinkage at the area where the fractured wall was formed was visually determined.

The test results shown in Table 1 show that the test piece of the comparative example had a large shrinkage rate and noticeable shrinkage, whereas the test piece of the example had a small shrinkage rate and no visible shrinkage. This indicates that it almost never occurred.

[0028]

[Table 1]

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of an airbag device pad of the present invention.

FIG. 2 is a perspective view showing an example of a conventional airbag device pad.

FIG. 3 is a sectional view showing an example of the airbag device pad.

[Explanation of symbols]

1. Pad of air bag device, 2 Upper wall part, ３　　　　periphery part, 11 Broken book meat part, 11a Broken portion forming groove, 11b Broken wall portion forming groove.

Claims (1)

[Claims] 1. A pad that is attached to an airbag device, is molded from a semi-rigid urethane material, and has a groove for forming a broken bottom part, wherein the semi-hard polyurethane material is a non-foaming formulation, and the pad for forming a broken bottom part is provided. A pad for an airbag device characterized by grooves being formed only on the back side.