JPH07125009A - Mold for air bag cover - Google Patents

Abstract

PURPOSE:To mold a surface side of a thin part with excellent appearance even when the thin part is formed on a ceiling wall of an air bag cover and reduce incidence of defective articles. CONSTITUTION:A forming mold 20 comprises a first split mold 21 for molding a top face side of a ceiling wall 2 in an air bag cover 1 and a second split mold 22 for molding the rear face side of the ceiling wall 2. The second split mold 22 is formed by connecting cores 24, 25 having a rear face side of a thin part 3 as a planned cutaway part in the ceiling wall 2 to be molded as a connecting line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die for molding a synthetic resin airbag cover used in a vehicle airbag device.

[0002]

2. Description of the Related Art Conventionally, an air bag cover is arranged so as to cover a folded air bag, and when the air bag is inflated, a thin wall portion, which is a portion to be broken, is broken by a pressing force of the air bag, Function to greatly inflate (see Japanese Utility Model Laid-Open No. 3-16557).

As shown in FIG. 1, an airbag cover 1 of this type includes a ceiling wall portion 2 and a side wall portion 4 extending from the back surface of the ceiling wall portion 2 into a substantially rectangular tube shape. In a portion surrounded by the side wall portion 4 in, a thin portion 3 as a scheduled break portion is arranged in an “H” shape. In addition, 4a is
Mounting holes provided after molding, and these mounting holes 4a are
It is used when the cover 1 is attached to the body (usually a bag holder) side of the airbag device by using a rivet or the like.

Mold 10 for manufacturing the airbag cover 1.
2 includes a first split mold 11 for molding the front surface side of the ceiling wall portion 2 and a second split mold 12 for molding the back surface side of the ceiling wall portion 2 and the side wall portion 4, as shown in FIG. Composed. Usually, the first split mold 11 is the fixed side, and the second split mold 12 is the movable side. In addition, 13 is an extrusion pin for releasing the molded cover 1.

Further, as shown in FIG. 1, the gate 10b for injecting the molding material M into the cavity 10a of the molding die 10 is arranged at the side surface portion of the outer peripheral edge of the ceiling wall 2 to be molded.

[0006]

In the conventional molding die 10, when the molding material M is injected from the gate 10b into the cavity 10a that has been clamped, the final fusion portion of the molding material M becomes the portion of the thin portion 3 to be molded. Was becoming. By the way,
Even if the location of the gate 10b was changed, since the thin portion 3 to be molded was narrow, the final fusion portion remained the molding portion of the thin portion 3. The thin portion 3
By arranging the gate 10b at the molding portion of, the final fusion portion of the molding material can be removed from the portion of the thin portion 3. However, with such a configuration, the thin portion 3 is formed in relation to the gate mark.
It cannot be done because the thickness of the fluctuates greatly.

Therefore, in the cover 1 molded by using the molding die 10, weld marks and air pockets may be generated at the thin wall portion 3 on the surface side of the ceiling wall portion 2, resulting in a defective product. there were.

The present invention solves the above-mentioned problems. Even if a thin wall portion is formed on the ceiling wall portion of the airbag cover, the appearance of the surface side of the thin wall portion can be satisfactorily molded, resulting in a defective product. An object of the present invention is to provide a molding die for an airbag cover, which can suppress the occurrence rate.

[0009]

A mold according to the present invention is for molding an airbag cover made of synthetic resin, in which a thin wall portion as a breakable portion is formed in a ceiling wall portion,
A first split mold for molding the front surface side of the ceiling wall portion, and a second split mold for molding the back surface side of the ceiling wall portion, the airbag cover molding die comprising: It is characterized in that the half mold is constructed by joining cores having a joining line on the back surface side of the thin portion to be formed.

[0010]

In the molding die according to the present invention, even if the molding material is injected into the cavity after the mold is clamped and the final fusion site of the molding material becomes the molding portion of the thin portion, the second split mold is used. Since the core in which the joining line is arranged in the molding portion of the thin portion is arranged in the, the air or the like enters the second split mold through the joining line of the core. Therefore, on the surface side of the thin portion, the occurrence of weld marks and air pools that deteriorate the appearance of the airbag cover can be suppressed.

Therefore, in the molding die according to the present invention,
Even if the thin wall portion is formed on the ceiling wall portion of the airbag cover, the appearance of the front surface side of the thin wall portion can be favorably molded, and the incidence of defective products can be suppressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The molding die 20 of the embodiment shown in FIGS. 3 and 4 is for molding the synthetic resin airbag cover 1 shown in FIG. 1 by injection molding, and molding the surface side of the ceiling wall portion 2. It is configured to include a 10-die 21 and a second die 22 for forming the back surface side of the ceiling wall portion 2 and the side wall portion 4 having a substantially rectangular tube shape. The first split mold 21 is the fixed side, and the second split mold 2 is
2 is the movable side. The molding material M for the cover 1 is S
It is a thermoplastic elastomer such as EBS / TPO / TPEE.

The second split mold 22 comprises a main body 23, two cores 24 and 25, and two extruding blocks 26 and 26.

Each extruding block 26 is a first / second half mold 21.
When the mold 22 is opened, the molded airbag cover 1 is pushed out from the second split mold 22 in parallel with the mold opening direction, and "H" in the thin portion 3 of the ceiling wall 2 to be molded.
It is arranged in a symmetrical position with the horizontal bar portion in between, at a portion for forming the inner peripheral surface side of the side wall portion 4 on the back surface of the ceiling wall portion 2 in the second split mold 22 (see the chain double-dashed line in FIG. 6). ).

Further, each extruding block 26,
Side surface mold surface 26 for molding the inner peripheral surface side of the side wall portion 4 for molding
a, an end surface mold surface 26b that is connected to the side surface mold surface 26a to form the end surface of the side wall portion 4, and a back surface mold surface 26c that is connected to the side surface mold surface 26a and forms the back surface of the ceiling wall portion 4.
And are equipped with.

Each of these extrusion blocks 26 is
The second split mold 22 is connected to the first split mold 21 by a rod 26d that is inserted through the main body 23 and connected to an extrusion plate (not shown).
When opening the mold away from, parallel to the mold opening direction,
It will be moved to the first split mold 21 side.

The cores 24 and 25 are arranged at symmetrical positions with the horizontal bar portion of the "H" shape in the thin wall portion 3 of the ceiling wall portion 2 to be formed therebetween, and are fastened to the main body 23 by bolts 27, respectively. The core 24 includes a back front mold surface 24a for molding the front side of the back surface of the ceiling wall 2, and the core 25 includes a back rear mold surface 25a for molding the rear side of the ceiling wall 2. I have it. Further, the cores 24 and 25 are flush with the side surface molding surface 26a of each extruding block 26, and the side surface molding surface 24b for molding the inner peripheral surface side of the front wall portion 4F and the rear wall portion 4B of the side wall portion 4. 25b (see the chain double-dashed line in FIG. 6).

The main body 23 is composed of the above-mentioned mold surfaces 24a and 24b.
-A predetermined cavity mold surface 23a so that the rear surface side of the ceiling wall portion 2 and the inner and outer peripheral surfaces and the end surfaces of the side wall portion 4 can be molded in a portion excluding 25a, 25b, 26a, 26b, 26c.
It is configured with.

As shown in FIGS. 4 and 6, the joining line between the back surface mold surface 24a of the core 24 and the back surface mold surface 25a of the core 25 and the cavity mold surface 23a of the main body 23 is formed as shown in FIGS. The thin wall portion 3 is arranged along the back surface side of the "H" vertical bar portion. The joining line between the back surface mold surface 24a of the core 24 and the back surface mold surface 25a of the core 25 is "H" of the thin portion 3 to be molded, as shown in FIGS.
It is arranged along the back side of the horizontal bar portion of the character.

A gate 20b for injecting a molding material M for molding the cover 1 into the cavity 20a at the time of mold clamping.
As in the conventional case, as shown in FIGS. 4 and 6, the ceiling wall portion 2
Is arranged on the side surface portion of the outer peripheral edge of.

The operation mode of the mold 20 of the embodiment will be described. First, the cavity 20 of the mold 20 which has been clamped.
The molding material M is injected into the inside a through the gate 20b, as shown in FIG.
As shown in 4, the airbag cover 1 is molded.

At this time, even if the final fusion portion of the molding material M becomes the molding portion of the thin portion 3, the plurality of cores 24 having the joining lines arranged in the molding portion of the thin portion 3 on the second split mold 22.
Since 25 is arranged, air or the like is applied to the core 24.2.
It will enter into the second split mold 22 through the joining line of No. 5. Therefore, on the front surface side of the thin portion 3, the occurrence of weld marks and air pools that deteriorate the appearance of the airbag cover 1 is suppressed.

Thereafter, when the mold is opened, the second split mold 22 separates from the first split mold 21 as shown in FIG.
Each extruding block 26 adheres to the second split mold 22 to release the airbag cover 1 separated from the first split mold 21.

Therefore, in the molding die 20 of the embodiment, even if the final fusion site of the molding material M becomes the molding site of the thin portion 3, air or the like passes through the joining line of the cores 24 and 25 and inside the second mold 22. Since it will enter the thin portion 3 that has been molded
The appearance on the surface side of can be improved, and the incidence of defective products can be suppressed.

In the molding die 20 of the embodiment, the cover 1
At the time of mold release, each extruding block 26 can push the back surface of the ceiling wall portion 2 by the back surface mold surface 26c and also push the end surface of the side wall portion 4 by the end surface mold surface 26b. Compared with the above, the formed side wall portion 4 can be smoothly released from the deep groove-shaped forming portion. Further, since the molded side wall portion 4 can be smoothly released from the mold surface 26b for the end surface of each extrusion block 26,
The back surface die surface 26c of each extrusion block 26 can reduce the stress that pushes the ceiling wall portion 2, and it is also possible to prevent the extrusion block 26 from leaving a mark on the front surface side of the ceiling wall portion 2.

[Brief description of drawings]

FIG. 1 is a perspective view showing an airbag cover to be molded.

FIG. 2 is a sectional view showing a conventional molding die at the time of molding.

FIG. 3 is a cross-sectional view showing a molding die according to an embodiment of the present invention during molding.

FIG. 4 is a cross-sectional view showing a molding die of the same example at the time of molding, which corresponds to a portion IV-IV in FIG.

FIG. 5 is a cross-sectional view showing a state where the extrusion block of the embodiment is activated.

FIG. 6 is a bottom view of the molded airbag cover.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Airbag cover, 2 ... Ceiling wall part, 3 ... Thin part, 10/20 ... Mold, 11/21 ... 10% mold, 12/22 ... 20% mold, 24/25 ... Core.

Front page continuation (72) Takanobu Ikeda Inventor Takanobu Nishi Kasuga-cho, Aichi Ochiai 1 Nagachihata, Toyoda Gosei Co., Ltd. In the company

Claims (1)

[Claims] 1. A first split mold for molding a front surface side of the ceiling wall portion in order to mold an airbag cover made of a synthetic resin in which a thin portion as a breakable portion is formed in the ceiling wall portion, A second split mold for molding the back surface side of the ceiling wall portion, wherein the second split mold is a joining line for bonding the back surface side of the thin wall portion to be molded. A mold for an air bag cover, which is configured by joining the cores described above.