JP3036328B2 - Mold for airbag cover - Google Patents

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 an airbag cover made of synthetic resin used for an airbag device for a vehicle.

[0002]

2. Description of the Related Art Conventionally, an airbag cover is disposed so as to cover a folded airbag, and when the airbag is inflated, a thin portion, which is to be broken, is broken by the pressing force of the airbag. (See Japanese Utility Model Laid-Open No. 3-16557).

As shown in FIG. 1, this type of airbag cover 1 includes a ceiling wall portion 2 and a side wall portion 4 extending in a substantially rectangular cylindrical shape from the back surface of the ceiling wall portion 2. In a portion surrounded by the side wall portion 4, a thin portion 3 as a portion to be broken is arranged in an "H" shape. Reference numeral 4a denotes mounting holes provided after molding, and these mounting holes 4a are used when the cover 1 is mounted on the body (usually a bag holder) side of the airbag device using rivets or the like.

Mold 10 for manufacturing airbag cover 1
As shown in FIG. 2, a first mold 11 for molding the front side of the ceiling wall 2 and a second mold 12 for molding the back side and the side wall 4 of the ceiling wall 2 are provided. Be composed. Usually, the first split mold 11 is on the fixed side, and the second split mold 12 is on the movable side.

An extruding member for releasing the molded cover 1 from the split mold 12 is disposed. The conventional extruding member includes a large number of extruding pins 13 such as a round pin and a square pin having a small sectional area. Was composed of

[0006]

However, when the extrusion member of the conventional molding die 10 is constituted by the extrusion pins 13 having a small cross-sectional area, the following problems occur.

That is, the extrusion pin 13 is
Since the side wall 4 formed at the deep groove-shaped portion 12a formed at 0a is released from the mold, a large pressing force is required. On the molded cover 1 side, the ceiling wall portion 2 surrounded by the side wall portion 4 is formed with the thin portion 3 and is easily deformed.
Therefore, the shape of the distal end surfaces of the push pins 13 due to the pressing force of the push pins 13 when pushing out the cover 1 is
In some cases, the cover 1 remains on the surface of the ceiling wall 2 serving as a design surface.

Alternatively, the side wall 4 may be broken when the pushing pin 13 is pressed.

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problem, and to provide a mold for an airbag cover which can be released without damaging a ceiling wall or a side wall of the airbag cover. Aim.

[0010]

A mold according to the present invention includes a ceiling wall portion and a side wall portion extending from the back surface of the ceiling wall portion, and the ceiling wall portion surrounded by the side wall portion has a portion to be broken. In order to form an airbag cover made of a synthetic resin in which a thin-walled portion is formed, a first split mold for molding the front side of the ceiling wall, and a back side and the side wall of the ceiling wall are molded. An extruding member for extruding the molded airbag cover from the second mold in a direction parallel to the mold opening direction when the first and second molds are opened. Wherein the extruding member is disposed at a portion of the back surface of the ceiling wall in the second mold where the side wall inner peripheral surface or the outer peripheral surface is formed. The extrusion block is disposed as A mold surface for forming an inner peripheral surface or an outer peripheral surface, a mold surface for an end surface connected to the mold surface for the side surface to form an end surface of the side wall portion, and a ceiling wall portion connected to the mold surface for the side surface. And a back mold surface for molding the back surface.

[0011]

In the molding die according to the present invention, when the extrusion block of the extrusion member at the time of releasing the mold pushes out the airbag cover, the back surface of the ceiling wall is pressed by the back surface and the end surface of the side wall is pressed. It can also be pressed by the end face mold surface, and the molded side wall can be smoothly released from the deep groove-shaped molding portion.

Further, since the molded side wall portion can be smoothly released from the mold surface for the end surface of the extrusion block, the stress for pressing the ceiling wall portion on the mold surface for the back surface of the extrusion block can be reduced. Since the area in which the block presses the ceiling wall portion can be easily made larger than that of the extrusion pin, it is possible to prevent a mark from being left on the surface side of the ceiling wall portion.

Therefore, in the mold according to the present invention,
The mold can be released without damaging the ceiling wall and the side wall of the airbag cover.

[0014]

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 for molding the surface side of the ceiling wall 2. It is provided with a tenth mold 21 and a second mold 22 for molding the back side of the ceiling wall part 2 and the substantially rectangular side wall part 4. Note that the first split mold 21 is the fixed side, and the second split mold 2
2 is the movable side. The molding material M of the cover 1 is S
It is a thermoplastic elastomer such as EBS / TPO / TPEE.

The second mold 22 includes a main body 23 and two extrusion blocks 24. When the first and second molds 21 and 22 are opened, each extrusion block 24 holds the formed airbag cover 1 in parallel with the mold opening direction.
It is for pushing out from 2.

These extrusion blocks 24 are provided on the rear surface of the ceiling wall 2 of the second split mold 22 at symmetrical positions between the "H" -shaped horizontal bars in the thin portion 3 of the ceiling wall 2 to be formed. The side wall 4 is disposed at a position where the inner peripheral surface side is formed (see a two-dot chain line in FIG. 5).

Each of the extrusion blocks 24 is
Side surface mold surface 24 for molding the inner peripheral surface side of side wall portion 4 to be molded
a, an end surface 24b connected to the side surface 24a to form an end surface of the side wall portion 4, and a back surface surface 24c connected to the side surface 24a to form the back surface of the ceiling wall 4.
And The main body 23 is provided with each of the mold surfaces 2 described above.
4a, 24b, and 24c, except that the rear surface of the ceiling wall 2 and the inner and outer peripheral surfaces and end surfaces of the side wall 4 can be formed.
A predetermined cavity mold surface 23a is provided.

Further, each of the extrusion blocks 24 is opened when the second split mold 22 is separated from the first split mold 21 by a rod 24d which is inserted into the main body 23 and connected to an extrusion plate (not shown). , In parallel with the mold opening direction to the first split mold 21 side.

In the molding die 20, the cavity 2
As shown in FIGS. 3 and 5, a gate for injecting a molding material M for molding the cover 1 into the extrusion block 2a is provided in addition to the main gate 20b disposed on the side of the outer peripheral edge of the ceiling wall portion 2.
Auxiliary gates 20c, which are arranged at two locations, are additionally provided on the outer peripheral sides of the two end surfaces of the side wall 4 at the positions where the 4.24 are arranged. Incidentally, in the conventional molding die 10, only the main gate 20b was used.

The operating mode of the embodiment will be described. First, the molding material M is injected into the cavity 20a of the clamped molding die 20 through the gates 20b and 20c, and as shown in FIG. Molded.

Thereafter, when the mold is opened, the second mold 22 separates from the first mold 21 as shown in FIG.
Each extrusion block 24 releases the airbag cover 1 attached to the second mold 22 and separated from the first mold 21.

At this time, each extrusion block 24 can press the back surface of the ceiling wall portion 2 by the back surface mold surface 24c and also press the end surface of the side wall portion 4 by the end surface mold surface 24b. The formed side wall 4 can be released from the deep groove-shaped forming portion 22a.

The mold surface 2 for the end face of each extrusion block 24
4b, the molded side wall portion 4 can be smoothly released from the mold, so that the stress of pressing the ceiling wall portion 2 by the back surface mold surface 24c of each extrusion block 24 can be reduced.
Each extrusion block 24 is moved from the extrusion pin 13 to the ceiling wall 2.
Since the area for pressing is increased, it is possible to prevent traces from being left on the surface side of the ceiling wall portion 2 and achieve the same effects as those described in the section of the operation and effect of the invention described above.

In addition, in the molding die 20 of the embodiment, since the auxiliary gate 20c is provided in addition to the main gate 20b, when the molding material M is injected from the gates 20b and 20c, the molding material M is removed from the cavity 20a. The airbag cover 1 having a good appearance without flowing on the surface of the ceiling wall portion 2 where the side wall portion 4 is formed, smoothly flowing to a portion where the ceiling wall portion 2 and the side wall portion 4 are formed. Can be molded. Incidentally, in the conventional molding die 10, the cavity 10
Since the molding material M flows only from the main gate 20b into the molding portion 12a, the material M first flows into the molding portion of the ceiling wall portion 2 in the cavity 10a, and then flows into the molding portion 12a of the side wall portion 4. Since the molding material M flows and the molding portion 12a of the side wall portion 4 is formed as a deep groove, the pressure of the material M at the molding portion 12a of the side wall portion 4 decreases, and the surface of the ceiling wall portion 2 after molding. In some cases, sink marks and the like are generated on the side, and the appearance is reduced.

In the embodiment, the extrusion blocks 24.2 are used.
4 is arranged at a symmetrical position between the “H” -shaped horizontal bar portions of the thin portion 3 on the back surface side of the ceiling wall portion 2 to be formed, but the “H” shape of the thin portion 3 is shown. You may arrange | position to two vertical rod parts. In this case, in this case, the back mold surface 2 for molding the back surface of the ceiling wall 2 of the extrusion block 24.
4c, a portion for forming the back surface side of the thin portion 3 is disposed, and the extrusion block 2 is formed in order to form the thin portion 3 so as to smoothly continue with the "H" -shaped horizontal bar portion of the thin portion 3.
Strict precision control is required for returning the back mold surface 24c to the main body 23 in 4, for example. In order to solve this point, the extrusion block 24 may be arranged at a portion where the outer peripheral surface side of the side wall portion 4 is formed, as shown by a chain line in FIG. Of course, when the extrusion block 24 is arranged at a position where the outer peripheral surface side of the side wall portion 4 is formed, the position shown by the broken line in FIG. 5 may be used.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing a conventional mold during molding.

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

FIG. 4 is a sectional view showing a state in which the extrusion block of the embodiment is operated.

FIG. 5 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, 4 ... Side wall part, 10/20 ... Molding die, 11/21 ... First split mold, 12/22 ... Second split mold, 13/24 ... extrusion member, (13 ... extrusion pin, 24 ... extrusion block) 24a ... side surface mold surface, 24b ... end surface mold surface, 24c ... back surface mold surface.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Chisato Masutani 1 Ochiai Ogai, Kasuga-cho, Nishikasugai-gun, Aichi Prefecture Inside Toyoda Gosei Co., Ltd. 5-293850 (JP, A) JP-A-4-166314 (JP, A) JP-A-4-126222 (JP, A) JP-A-3-254919 (JP, A) JP-A-5-253964 (JP, A) A) JP-A-4-52117 (JP, A) JP-A-7-125009 (JP, A) JP-A-4-325346 (JP, A) JP-A-4-133706 (JP, A) JP-A-5 −104574 (JP, A) Japanese Utility Model Hei 6-81719 (JP, U) Japanese Utility Model Utility Model 3-16557 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/26- 45/44 B29C 33/00-33/76 B60R 21/20

Claims (1)

(57) [Claims] 1. A synthetic resin material comprising: a ceiling wall portion; and a side wall portion extending from a back surface of the ceiling wall portion, wherein the ceiling wall portion surrounded by the side wall portion has a thin portion formed as a portion to be broken. A first mold for molding the front side of the ceiling wall, and a second mold for molding the rear side of the ceiling wall and the side wall to form the airbag cover; A mold for an airbag cover, in which a pushing member for pushing out the molded airbag cover from the second mold in a direction parallel to the mold opening direction when the first and second molds are opened is provided in the 20% mold. The extrusion member is disposed as an extrusion block disposed at a portion of the second mold that forms the inner peripheral surface side or the outer peripheral surface side of the side wall portion on the back surface of the ceiling wall portion. Molds the inner peripheral surface side or the outer peripheral surface side of the side wall portion A surface mold surface, an end surface mold surface connected to the side surface mold surface to form the side wall end surface, and a back surface mold surface connected to the side surface mold surface and molding the ceiling wall back surface, A molding die for an airbag cover, comprising: