JP2519517B2 - Molding method for automobile decorative mold - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for molding a decorative molding for automobiles, and more particularly to a method for molding a decorative molding for automobiles having a good design surface.

[Prior Art] As a conventional automobile decoration molding of this type,
There is one shown in FIGS. 3 to 6.

FIG. 3 is a plan view of a conventional automobile decorative molding,
FIG. 4 is a central cross-sectional view of a conventional automobile decorative molding. FIG. 5 is an enlarged cross-sectional view of a main part of a conventional automobile decorative molding, and FIG. 6 is an enlarged cross-sectional view of a main part of another conventional automobile decorative molding.

In the figure, the decorative molding body 1 is usually continuously molded by extrusion molding or the like, and the plane shown in FIG. 3 cut into a predetermined length is the design surface. In addition, the terminal portion 2 is formed by injection molding at the tip of the decorative molding body 1, and one or both ends of the decorative molding body 1 continuously molded by the extrusion molding or the like has a predetermined specification. It was finished.

As shown in the cross-sectional view of FIG. 4, this type of automobile decoration molding is premised on that the front end surface 1a of the decoration molding main body 1 and the joint surface 2a of the terminal portion 2 are joined on a vertical plane. There is. Therefore, the thickness of the decorative molding body 1 and the thickness of the terminal 2 are formed to be substantially uniform.

The automobile decorative molding configured as described above is mounted on the vehicle body by a mounting means such as a double-sided adhesive tape or a clip arranged on the back side of the decorative molding body 1 and the terminal 2.

[Problems to be Solved by the Invention] As described above, the conventional automobile decorative molding shown in FIGS. 3 and 4 has a distal end surface of the decorative molding body 1 as shown in the sectional view of FIG. Although it is assumed that 1a and the joining surface 2a of the terminal portion 2 are joined on a vertical plane,
Due to the injection molding pressure when molding the terminal portion 2, the tip surface 1a of the decorative molding body 1 is curved as shown in FIGS. 5 and 6 of the case where the terminal portion is actually injection molded.

That is, the tip surface 1a of the decorative molding body 1 and the joint surface 2a of the terminal portion 2 are bonded to each other by the elasticity of the synthetic resin forming the decoration molding body 1 and the injection molding pressure for molding the terminal portion 2. The surface 2a side is curved in a convex shape toward the decorative molding body 1.

Further, the decorative molding body 1 and the terminal portion 2 are formed to have a substantially uniform thickness, but the elasticity of the synthetic resin forming the decorative molding body 1, the elasticity of the synthetic resin forming the terminal portion 2, and the like may not always be necessary. In some cases, the marks 3 are not substantially uniformed, and the sink marks 3 shown in the enlarged cross-sectional view of the main part of FIG. In particular, when the decorative molding body 1 and the terminal portion 2 do not look good on the design side, the terminal portion 2 may be colored, a glitter film may be attached, or the like.
This becomes remarkable in the case of the surface treatment having the function of enlarging the sink mark 3 on the joint surface 2a side.

On the other hand, when the injection molding pressure of the terminal portion 2 is reduced, an opening-shaped concave portion 4 as shown in the enlarged cross-sectional view of the main part of FIG. 6 is formed on the joint surface between them, and both the joint force and the appearance are improved. Is reduced.

Therefore, an object of the present invention is to provide a method for molding a decorative molding for automobiles in which a sufficient adhesive force between the decorative molding main body portion and the terminal portion is obtained, and moreover, a sink mark or a recess is not formed on the design surface.

[Means for Solving the Problems] In the method for molding an automobile decorative molding according to the present invention,
The mold forming the terminal portion is composed of a pair of mold members that form a cavity, is continuous from the molding surface of the cavity of at least one mold member, from the tip of the decorative molding body portion to the decorative molding body portion side, and The holding pressure for holding the decoration molding body is maximized at a position close to the tip of the decoration molding body by a predetermined distance, and from the point where the maximum holding pressure is applied to the tip of the decoration molding body. And the decorative molding body is held by a pair of mold members having the projections, and the decorative molding body is held by the pair of mold members having the projections. The terminal part is injection molded.

[Operation] In the present invention, when the terminal portion is formed on the decorative molding body body made of synthetic resin, the holding pressure for holding the decoration molding body portion is maximized at a predetermined distance close to the tip of the decoration molding body portion, By using a mold having a chevron-shaped protrusion that reduces the clamping pressure toward the tip from the predetermined distance, the decorative molding main body is injection-molded while the decorative molding main body is being clamped. It is possible to obtain a decorative molding for an automobile having a preferable finished design surface by obtaining a resistance force against the injection molding pressure at the time of injection molding the terminal portion by the tip of the portion.

[Example] Hereinafter, a method for molding a decorative molding for automobiles according to an example of the present invention will be described.

FIG. 1 is a sectional view showing a molding state of a method for molding a decorative molding for automobiles according to a first embodiment of the present invention.

In the figure, the decorative molding body 1 is continuously formed by extrusion molding or the like similar to the conventional one, and cut into a predetermined length, and the upper portion of FIG. 1 is the design surface.

The mold 10 is composed of a pair of upper and lower mold members of a lower mold 10A and an upper mold 10B. One mold member, the lower mold 10A, has a flat surface on which the decorative molding body 1 is placed and a terminal portion for injection molding. A part of the second cavity 11 is formed. The upper mold part 10B, which is the other mold member, holds and holds the decorative molding body part 1 together with the lower mold part 10A on which the decorative molding body part 1 is placed, and the cavities 11 of the terminal part 2 for injection molding. Part of is formed. The upper mold 10B and the lower mold 10A form the entire cavity 11 of the terminal portion 2.

The upper mold 10B is provided with a mountain-shaped convex portion 10b having a maximum height at a position located a distance L from the tip surface 1a of the decorative molding body portion 1, and the convex portion 10b is the decorative molding body portion. The maximum holding pressure between the upper mold 10B and the lower mold 10A that holds 1 is located at a distance L from the tip surface 1a of the decorative molding body 1. Then, from the distance L to the tip surface
In order to gradually reduce the holding pressure toward 1a, the height up to the tip surface 1a of the decorative molding body 1 is lower than that of the conventional horizontal cavity line shown by the broken line in FIG. Is forming.

In this embodiment, a part of the molding surface of the cavity 11 is thicker than the conventional horizontal cavity line shown by the broken line in FIG. It is formed continuously from the inclined surface.

The position and value of the maximum value of the height of the convex portion 10b are the distance L from the tip surface 1a of the decorative molding body 1, the elasticity of the synthetic resin material forming the decorative molding body 1, the decorative molding body 1 It is determined by the area of the tip surface 1a, the injection molding pressure of the terminal portion 2, and the like. That is, the height of the convex portion 10b of the upper mold 10B is to obtain a resisting force against the injection molding pressure on the tip surface 1a of the decorative molding body 1, to prevent movement of the tip surface 1a of the decoration molding body 1, or It is determined by the degree to which the tip surface 1a of the decorative molding body 1 is bent outward in advance.

The molding method of this type of automobile decorative molding is performed as follows.

The upper mold 10B, which is one of the mold members constituting the mold 10, holds and holds the decorative molding main body 1 together with the lower mold 10A of the other molding member on which the decorative molding main body 1 is placed, and at the same time, the injection is performed. A part of the cavity 11 of the terminal portion 2 to be molded is formed, and together with the lower mold 10A, the entire cavity 11 of the terminal portion 2 is formed.

In this way, the lower mold 10A, the upper mold 10B, and the decorative molding body 1
When the cavity 11 of the terminal portion 2 is formed with the tip surface 1a of the above, the tip surface 1a of the decorative molding main body portion 1 forming the cavity 11 of the terminal portion 2 is, as described above, the mountain-shaped convex portion of the upper mold 10B. In order to obtain a resistance force against the injection molding pressure of the terminal portion 2 by 10b, the tip surface 1a of the decorative molding body portion 1 is in a flat state as a movement stop, or the tip surface 1a of the decoration molding body portion 1 is outwardly moved outward. It is in a state of being bent.

That is, the decoration molding body 1 pressed by the chevron-shaped protrusions 10b of the upper mold 10B has a high density at the pressed portion, and further, the holding pressure of the part of the decoration molding body 1 gradually decreases. Escape in the direction of the tip surface 1a of the decorative molding body 1 that results, the tip surface 1a of the decoration molding body 1 is bent in a convex shape, or the pressed portion of the decoration molding body 1 has a high density. And the elastic hardness increases, and the decorative molding body 1
Even if the tip end surface 1a of the is obtained with a pressure close to the injection molding pressure, it does not change.

Under this condition, a predetermined synthetic resin material is injected at a predetermined injection molding pressure into the cavity 11 for molding the lower mold 10A, the upper mold 10B, and the end portion 2 formed by the tip surface 1a of the decorative molding body 1. The terminal portion 2 is formed on the tip surface 1a of the decorative molding body portion 1.

Therefore, the terminal portion 2 molded on the tip surface 1a of the decorative molding body 1 can be molded without bending the tip surface 1a of the decoration molding body 1 inward of the decoration molding body 1, and the terminal portion 2 can be formed. The joint surface 2a of is a smooth vertical plane without irregularities. Therefore, the volume change at the boundary between the tip surface 1a of the decorative molding body 1 and the joining surface 2a of the terminal portion 2 is made uniform,
As a result, the decorative molding body portion 1 and the terminal portion 2 are joined with a substantially uniform thickness, and the joining surface 2a of the terminal portion 2 is joined.
The volume change in the vicinity is made substantially uniform, and there is no occurrence of sink marks or open concave portions on the design surface side of the terminal portion 2. Moreover, the state of the joint surface 2a of the terminal portion 2 after molding can be set by the injection molding pressure for molding the terminal portion 2, so that the injection molding pressure can be increased, and the sink mark or the concave portion of the terminal portion 2 can be used to decorate the molding. The joining state at the boundary between the front end surface 1a of the main body portion 1 and the joining surface 2a of the terminal portion 2 does not deteriorate.

FIG. 2 is a cross-sectional view showing a molding state of the method for molding a decorative molding for automobiles according to the second embodiment of the present invention. In addition,
In the figure, the same reference numerals and symbols as those of the first embodiment indicate the same or corresponding components as those of the first embodiment, and therefore, duplicated description will be omitted here. In particular, in this embodiment, only differences from the first embodiment will be described.

In this embodiment, the upper mold which is one of the mold members of the first embodiment
What is provided with the chevron-shaped convex portion 10b on the side 10B is provided with the chevron-shaped convex portion 10a on the side of the lower die 10A which is the other die member.
Although the two are not functionally different, when the holding force of the decorative molding body 1 is increased, the pressing force is partially increased on the design surface of the decorative molding body 1 as in the first embodiment. Since it does not come into direct contact with the protruding portion 10b, the finished design surface can be improved.

When implementing the present invention, the functions of the first and second embodiments described above may be combined. That is, it is possible to obtain the mold 10 that simultaneously includes the mountain-shaped convex portion 10b on the upper mold 10B side and the mountain-shaped convex portion 10a on the lower mold 10A side.

As described above, the method of molding a decorative molding for automobiles according to the above-described embodiment is an automobile having the decorative molding main body 1 made of synthetic resin and the terminal portion 2 formed by injection molding at the tip of the decorative molding main body 1. In the method for molding a decorative molding for metal, the mold 10 forming the terminal portion 2 is composed of a pair of mold members (upper mold 10B, lower mold 10A) forming a cavity 11, and the cavity 11 of at least one mold member 10B. From the tip of the decorative molding body 1 on the side of the decorative molding body 1 and at a distance L close to the tip of the decorative molding body 1, The holding pressure for holding is maximized, and a mountain-shaped convex portion 10b for holding the decoration molding body 1 while sequentially reducing the holding pressure from the distance L toward the tip thereof is provided. The convex portion The terminal portion 2 is injection-molded in a state of being held by a pair of mold members 10A and 10B provided with 10b.

Therefore, in the terminal portion 2 formed on the tip surface 1a of the decorative molding body 1, the volume change of the boundary portion between the tip surface 1a of the decoration molding body 1 and the joint surface 2a of the terminal 2 is made uniform, and the decoration Since the molding body 1 and the terminal portion 2 are joined to each other with a substantially uniform thickness, no sink mark or recess is formed on the design surface side of the terminal portion 2. In addition, since the state of the joint surface 2a of the terminal portion 2 after molding can be set by the injection molding pressure for molding the terminal portion 2, it is possible to perform the molding without lowering the injection molding pressure, and by the sink mark or the concave portion of the terminal portion 2. Tip surface of the decorative molding body 1
The bonding state at the boundary between 1a and the bonding surface 2a of the terminal portion 2 does not deteriorate.

By the way, even if the front end surface 1a of the decorative molding body portion 1 is excessively curved outward, the substantial thickness of the synthetic resin material at the boundary portion of the joining surface 2a of the injection-molded terminal portion 2 is thereby increased. However, it becomes thinner than the thickness of the decorative molding body 1, and sink marks do not occur there.

By the way, the mountain-shaped convex portion 10b and / or the lower mold 10 of the upper mold 10B inserted into the back surface side of the decorative molding body 1 of the above-mentioned embodiment.
The mountain-shaped convex portion 10a of A is positioned at a distance L from the tip surface 1a of the decorative molding body 1, but when the present invention is carried out, the tip surface of the decoration molding body 1 of the above embodiment is
To be precise, the position at a distance L from 1a is the elasticity of the synthetic resin material forming the decorative molding body 1, the area of the tip surface 1a of the decorative molding body 1, the chevron-shaped projection 10a of the mold 10, and Although it is determined by the width and height of the mountain-shaped convex portion 10b, the injection molding pressure of the terminal portion 2, the thickness and shape of the convex portion 10a and / or the convex portion 10b, by the way, by the way, the tip surface of the decorative molding body 1 Even if 1a is curved outward in a convex shape, it does not affect the design surface of the molded product, and as a result, the decorative molding body 1
The back side of the decorative molding body 1 may be located near the tip of

Further, in the above-described embodiment, the mold provided with the mountain-shaped convex portion that reduces the holding pressure from the predetermined distance L toward the tip thereof.
Although 10 is used, when carrying out the present invention, the reduction rate of the holding pressure can be arbitrarily selected depending on the property of the decorative molding body 1.

[Effects of the Invention] As described above, the method of molding an automobile decorative molding of the present invention includes a decorative molding main body made of synthetic resin and a terminal portion formed by injection molding at the tip of the decorative molding main body. In the method of molding a decorative molding for automobiles, the mold forming the terminal portion includes a pair of mold members that form a cavity and is continuous from the molding surface of the cavity of at least one mold member, From the tip of the decorative molding body portion side, and at a predetermined distance near the tip of the decoration molding body portion, the holding pressure for holding the decoration molding body portion is maximized, and the maximum holding pressure is applied. From the point where the decorative molding body is gradually reduced toward the distal end of the decorative molding body, the decorative molding body is provided with a mountain-shaped convex portion that holds the decorative molding body. Since the terminal portion is injection-molded in the decorative molding body portion while being sandwiched by the pair of mold members having the convex portion, the terminal portion molded on the tip surface of the decorative molding body portion is The main body portion and the terminal portion are joined with a substantially uniform thickness, and sink marks do not occur on the design surface side of the terminal portion. Also,
By changing the height and position of the convex portion of the chevron, it is possible to set the state of the joint surface of the terminal part after molding according to the injection molding pressure for molding the terminal part, so it is necessary to lower the injection molding pressure. It can be molded without any trouble, and the sinking of the terminal portion does not deteriorate the joining state of the boundary portion between the front end surface of the decorative molding body portion and the joining surface of the terminal portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molding state of a method for molding an automobile decorative molding according to a first embodiment of the present invention, and FIG. 2 shows a molding state of a molding method for an automobile decorative molding according to a second embodiment of the present invention. Sectional drawing shown in FIG. 3, FIG. 3 is a plan view of a conventional automobile decoration molding, FIG. 4 is a central cross-sectional view of a conventional automobile decoration molding, and FIG. 5 is an enlarged cross-sectional view of a main part of a conventional automobile decoration molding. FIG. 6 and FIG. 6 are enlarged cross-sectional views of main parts of another conventional automobile decorative molding. In the figure, 1 is a decorative molding body part, 2 is a terminal part 10A is a lower mold, 10B is an upper mold, 10a is a convex part, and 10b is a convex part. In the drawings, the same reference numerals and symbols indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A method of molding a decorative mall for an automobile, comprising: a decorative molding main body made of synthetic resin; and a terminal formed by injection molding at a tip of the decorative molding main body. The mold is composed of a pair of mold members forming a cavity, is continuous from the molding surface of the cavity of at least one of the mold members, is on the decorative molding main body side from the tip of the decorative molding main body, and the decorative molding main body At a predetermined distance close to the tip of the part, the holding pressure for holding the decorative molding body is maximized, and the holding pressure is applied from the point to which the maximum holding pressure is applied toward the tip of the decorative molding body. The decorative molding body is provided with a mountain-shaped convex portion that holds the decorative molding body portion while being sequentially reduced, and the decorative molding body portion is sandwiched by a pair of mold members having the convex portion. A method of molding a decorative molding for automobiles, characterized in that a terminal portion is injection-molded on a main body of the vehicle.