JPH11320595A - Bead molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a beads molding die which is free from the possibilities that burrs would be generated on beads foam moldings and can prevent defective molding due to heating irregularities from being generated and further can be fabricated simply, in the beads molding die to be used for molding beads foam moldings. SOLUTION: Templates 54, 64 for cavity formation which make up the mold surface of a cavity C in the split halves 50, 60 of a die which can be opened and clamped to each other, are formed of an air-permeable metallic material. Consequently, a vent piece is no longer required and it is possible to heat a resin uniformly through the mold surface of the cavity C and obtain smooth- surface beads moldings without the formation of burrs such as slit marks. Further, discontinuing the use of the vent piece contributes to the simplification of an operation to fabricate the die.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bead molding die used for a foamed bead such as a sun visor core, and more particularly, to a trace of a slit hole for steam or the like remaining on the surface of the foamed bead. The present invention relates to a bead molding die that has a good appearance when a skin material is adhered and that can significantly reduce the processing cost of the die.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, an automobile sun visor 1 having a sunshade function is installed diagonally above occupants in a driver's seat and an auxiliary seat. The sun visor body 2 having the light shielding area is rotatably supported by the rotation shaft 1a,
The sun visor body 2 can be rotated in the vertical and horizontal directions by fixing the bracket 1b to which the rotation shaft 1a is attached to the ceiling side and rotating the rotation shaft 1a around the axis with respect to the bracket 1b. It is supported to be.

The sun visor body 2 is formed by enclosing an outer surface of a sun visor core 3 with a sun visor skin 4. In particular, as a material used for the sun visor core 3, light-weight beads having excellent impact resistance are used. There is a tendency for foamed molded articles to be frequently used.

FIG. 6 shows a bead molding die 5 used for molding the sun visor core 3 using polypropylene beads as a material. The bead molding die 5 is a divided part which can be opened and clamped mutually. The cavities C defined by the molds 5a and 5b are filled with the expandable bead material P from the bead supply feeder 6, and after the filling, steam is supplied to the molds 5a and 5b. Steam is supplied from the pipe 7, and steam heated to a predetermined temperature is supplied into the cavity C through the slit holes 8a of the vent pieces 8 embedded in the molds 5a and 5b. The foaming reaction is induced, and the sun visor core 3 along the shape of the cavity C is formed.

[0005]

However, in the conventional bead molding die 5, the front end surface of the vent piece 8 embedded in the split die 5a, 5b and the split die 5a, 5b are not required.
As shown in FIG. 7, the surface of the sun visor core 3 formed using the bead forming die 5 has the vent piece 8 The burrs corresponding to the slit holes 8a remain as the convex portions 3a, and as shown in FIG. 8, when the sun visor skin 4 is adhered to the surface of the sun visor core 3, the set portion of the vent piece 8 becomes the convex portion a. There is a drawback that it protrudes and lowers the external appearance and feel.

Further, due to the configuration of the bead molding die 5, a hole for accommodating the vent piece 8 is opened in each of the divided die 5a and 5b.
The installation work of the vent piece 8 is complicated, for example, the vent piece 8 is buried and fixed by driving into each accommodation hole, which leads to an increase in the number of processing steps of the mold, and a skin material is attached to the curved surface of the sun visor core 3. In this case, the skin material is stretched, and the unevenness of the surface of the sun visor core 3 appears humblely on the surface, so that the installation location of the vent piece 8 is restricted. Had become.

The present invention has been made in view of the above circumstances, and has a bead forming metal capable of forming a foamed bead formed by a skin material into a required shape like a sun visor core of an automobile sun visor. In the mold, we provide a bead molding die that has good appearance and feel to the touch of the product, shortens the processing time of the die, and can increase the efficiency of steam supply during bead foam molding. It is intended to be.

[0008]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a split mold capable of forming a cavity having a desired shape and capable of being opened and closed by a mold, and a foamable bead material in the cavity. In order to perform a foaming reaction of the bead material supply feeder and the foamable bead material to be supplied,
In a bead molding die provided with steam supply means for supplying steam into a cavity, the mold plate for forming a cavity of the split die is formed of a gas-permeable metal.

Here, the bead molding dies are constituted by divided dies which can be opened and clamped to each other, and each of the divided dies has an air chamber in which steam from the outside is supplied. Each split mold is provided with a cavity forming template so that a cavity having a desired shape can be formed, and a bead supply feeder capable of supplying an expandable bead material into the cavity is provided with one of the split molds. It is installed on the side. Here, the foamable bead material may be appropriately selected from a polypropylene (PP) bead material, a polyethylene (PE) bead material, a polystyrene (PS) bead material, and the like. ) Beads are preferred.

Further, as a gas permeable metal material used for the cavity forming template, a stainless steel plate having a hole diameter of 20 is used.
In addition to a material having a plurality of holes of about 100 μm, a sintered metal material or the like can be used.

As is apparent from the above configuration, claim 1
According to the described invention, since the mold plate constituting the cavity mold surface of the split mold for bead molding is made of a breathable metal, the steam hole trace of the steam supplied at the time of bead foam molding is very small. Due to the fineness, burrs do not occur on the surface of the bead foam molded article.

Further, after forming a mold plate for forming a cavity by molding a gas-permeable metal to have a desired curved surface shape,
The man-hour can be attached to the split mold body, and the total man-hour can be reduced as compared with the man-hour for driving and fixing a plurality of vent pieces to the conventional split mold.

Further, unlike the conventional mold structure, heating unevenness does not occur between the place where the vent piece is provided and the place where the vent piece is not provided, and the steam is uniformly supplied into the cavity through the entire surface of the cavity mold. Thus, unevenness in heating does not occur, and in particular, excellent moldability can be ensured even in a curved portion.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a bead molding die according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a front view showing an automobile sun visor using a sun visor core formed by using the bead molding die according to the present invention, FIG. 2 is a cross-sectional view showing the configuration of the automobile sun visor, and FIG. Is an explanatory view showing a schematic configuration of an embodiment of a bead molding die according to the present invention, and FIG. 4 is a partial cross-sectional view showing a sun visor core formed by using the bead molding die shown in FIG.

In FIG. 1 and FIG. 2, a sun visor 10 for an automobile is installed diagonally above a driver's seat, and a sun visor body 11 having a sunshade function is rotatably supported by a rotation shaft 12. A bracket 13 for inserting and holding the shaft 12 is fixed to the ceiling surface 14. Further, an auxiliary knob 1 provided at the other end opposite to the rotating shaft 12
5 is attached to a holder 16 attached to the ceiling surface 14, and the sun visor body 11 is composed of a rotating shaft 12 and an auxiliary knob 15.
Are supported by the following two points.

Furthermore, since the sun visor body 11 desirably has a light weight and an appropriate shape retention property and an excellent shock absorbing function when an occupant's head collides with the vehicle at the time of a collision, the sun visor body 11 is lightweight and shock resistant. The outer surface of a sun visor core 20 made of a foamed bead having excellent properties is covered with a sun visor skin 30 made of a PVC sheet.

In the present embodiment, a 20-fold expanded PP bead foam is used as the bead foam, but it is possible to adjust the expansion ratio variably or to substitute a polyethylene bead foam. Further, as the sun visor skin 30, besides a PVC sheet, a laminate of a PVC sheet on the back surface of a nonwoven fabric or a cloth can be used.

The present invention is characterized by the structure of a bead molding die used in molding the sun visor core 20 in the sun visor 10 for an automobile. The product surface of the sun visor 10 is smooth and excellent in appearance and touch. When the sun visor skin 30 is applied to the surface of the sun visor core 20 with an appropriate tension, the operation of attaching the sun visor skin 30 can be performed smoothly.

FIG. 3 shows a schematic configuration of the bead forming die 40. The bead forming die 40 is divided by a bead forming split die (a lower die 50 and an upper die 60, which will be described below). The lower die 50 has a lower die wall 52 attached to an upper surface of a fixed plate 51, and extends along the inner periphery of the lower die wall 52. A cavity forming mold plate 54 constituting a cavity mold surface is fitted and fixed to the provided step portion 53.

On the other hand, the upper die 60 is connected to an elevating cylinder (not shown), and an upper die wall 62 is attached to the lower surface of a movable plate 61 which can move up and down. A cavity forming mold plate 64 constituting a cavity mold surface is fitted and fixed to the stepped portion 63 provided.

The upper and lower dies 50 and 60 are provided with air chambers 55 and 65 therein. Each of the upper and lower dies 50 and 60 is provided with a steam pipe 70 so that high-temperature steam can be supplied from the outside. The mold 60 is provided with a bead supply feeder 80 for supplying bead material.

The bead forming die 40 according to the present invention is characterized in that the conventional vent pieces are eliminated and the cavity forming plates 54 and 64 are made of a breathable metal material.

That is, in the present embodiment, the mold plates 54 and 64 for cavity formation have an infinite number of vent holes having a hole diameter of 20 to 100 μm, and the thickness of each of the mold plates 54 and 64 is about 4 to 10 mm. Is set.

Therefore, if the split molds 50 and 60 are clamped, the cavity C is formed between the cavity forming mold plates 54 and 64.
After filling the cavity C with the expandable PP bead material P through the bead supply feeder 80 and then supplying steam into the air chambers 55 and 65 of the upper and lower dies 50 and 60 from the steam pipe 70, Since the cavity forming templates 54 and 64 are made of a breathable metal material, steam is supplied into the cavity C, and foaming of the foamable PP bead material is performed.

At this time, there is no problem such as uneven heating between the part where the vent piece is installed and the part where the vent piece is not installed, and there is no problem as compared with the mold structure using the conventional vent piece. And uniform heating can be reliably performed to prevent molding unevenness. Further, unlike the related art, the vent holes are not left as traces, and the vent holes are very fine. ,
The molding of the sun visor core 20 having an excellent smooth surface without generation of burrs is completed.

As described above, in addition to the function and effect that the moldability of the sun visor core 20 is excellent, the bead molding die 40
With regard to the structure (1), the conventional operation of driving and fixing the vent piece can be eliminated, which is advantageous also in terms of mold processing.

In this embodiment, the hole diameter is 20 to 1
Although a stainless steel plate having an infinite number of air holes of about 00 μm was used, other materials such as sintered metal may be used as long as they are air permeable metals having excellent heat resistance, water resistance, and mold release properties.

[0029]

As described above, the bead molding die according to the present invention has the following special effects.

(1) According to the present invention, since the cavity forming mold plate constituting the cavity mold surface is made of a gas permeable metal, the molded bead foam molded article has:
No traces of conventional steam holes etc. remain, the surface of the bead foam molded body can emphasize the smoothness, and the product composed of the bead foam molded body surface covered with skin material ensures beautiful appearance design It has the effect of being able to.

(2) According to the bead-forming mold according to the present invention, the cavity-forming mold plate constituting the cavity mold surface is made of a gas-permeable metal. There is no heating unevenness between the mold and the non-installed portion, and uniform heating can be performed along the mold surface of the cavity, so that molding unevenness due to heating unevenness does not occur on the surface of the bead foam molded body, and (1) Similarly, a product formed by enclosing the surface of a bead foam molded product with a skin material has an effect that a beautiful appearance design can be secured.

(3) According to the bead molding die according to the present invention, since the cavity forming plate constituting the cavity die surface is made of a gas-permeable metal, the cavity die surface is formed on the divided die body. It is only necessary to attach the cavity forming mold plates constituting each, and the complicated work of arranging multiple vent pieces in the mold in consideration of the steam supply efficiency as in the past can be eliminated, and the mold This has the effect of greatly simplifying the number of processing steps and leading to significant cost reduction.

[Brief description of the drawings]

FIG. 1 is a front view showing an automotive sun visor using a sun visor core molded using a bead molding die according to the present invention.

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

FIG. 3 is a schematic diagram showing a configuration of an embodiment of a bead molding die according to the present invention.

FIG. 4 is a partial cross-sectional view showing a sun visor core formed by using the bead forming die shown in FIG. 3;

FIG. 5 is a partially broken front view showing a conventional automobile sun visor.

FIG. 6 is a schematic view showing a bead molding die used for molding a conventional sun visor core.

7 is a partial cross-sectional view showing a sun visor core formed by using the conventional bead forming die shown in FIG.

FIG. 8 is an explanatory view showing a conventional work of attaching a sun visor epidermis to a sun visor core.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sun visor for vehicles 11 Sun visor main body 12 Rotating shaft 20 Sun visor core 30 Sun visor skin 40 Bead forming die 50 Lower die 51 Fixed plate 52 Lower die wall 54 Cavity forming die plate 55 Air chamber 60 Upper die 61 Movable plate 62 Upper mold wall 64 Cavity forming mold plate 65 Air chamber 70 Steam piping 80 Bead supply feeder P Foamable PP bead material C Cavity

Claims (2)

[Claims] A split mold (50, 6) capable of forming a cavity (C) having a desired shape and capable of opening and closing each other.
0) and a foamable bead material (P) in the cavity (C)
Bead forming apparatus comprising: a bead material supply feeder (80) for supplying steam; and steam supply means (70) for supplying steam into the cavity (C) in order to cause a foaming reaction of the expandable bead material (P). In the mold for beads, the mold plate (54, 64) for forming the cavity (C) of the split mold (50, 60) is formed of a gas-permeable metal. 2. The air-permeable metal has a pore size of 20 to 100.
2. The bead-forming mold according to claim 1, wherein the mold is formed from a stainless steel plate having an infinite number of μm holes.