JP3226408B2 - Automobile molding and manufacturing method thereof - 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 represented by an automobile side protector molding which is mounted on the outermost side such as a side door of an automobile.

[0002]

2. Description of the Related Art Conventionally, among side protector moldings for automobiles (hereinafter abbreviated as "side moldings"), a reinforcing core is closely fixed to an inner peripheral surface thereof as shown in FIG.
11 is known. The side molding is usually formed by injecting a resin into a mold provided with a cored bar.
Although an extrusion molding method or a blow molding method can also produce a side molding, it is disadvantageous in terms of man-hours and production costs, and the injection molding method is exclusively used.

A side molding m1 shown in FIG. 10 is manufactured by arranging an arc-shaped core metal 21 in a mold and injecting a resin. The core metal 21 is tightly fixed inside the molding body 22. This configuration has a disadvantage that it is easily bent to the side of the vehicle, that is, to an external force F in the direction shown.

On the other hand, a side molding m shown in FIG.
2 are bent portions 32 facing each other inside the both ends in the width direction.
The C-shaped core metal 31 on which a and 32a are respectively formed is arranged in a mold, and is manufactured by injecting a resin. Mall body 3
The core metal 31 is closely fixed to the inside of 2. This configuration increases the rigidity to the side of the vehicle, that is, the external force F in the direction shown, but has a disadvantage in molding to realize this configuration. That is, a slide die for punching out the bent portion of the core metal 31 which is tightly fixed inside the molding body 32 is indispensable, and the structure of the die becomes complicated, and the manufacturing cost is increased.

[0005]

When the structure of the mold becomes complicated, the production efficiency decreases. Manufacturing of a molding using a mold having a simple structure such as opening up and down has priority. Therefore, it is preferable to manufacture a molding capable of withstanding an external force by making the cross-sectional shape of the cored bar corrugated or the like.

However, if the cross section of the core is corrugated or the like, the contact area between the resin and the core increases, and the fluidity of the resin deteriorates. In particular, in a relatively thin part such as a side molding, the resin pressure increases, a wavy pattern remains on the outer surface of the side molding, and burrs occur near the injection port. In addition, when the side molding becomes longer, for example, when it becomes 60 cm or more, the resin cannot reach the tip due to the increased flow resistance.

An object of the present invention is to provide a resin having strength capable of withstanding an external force, a beautiful outer surface (decorative surface), a simple mold structure, and a low flow resistance of a resin at the time of injection. It is to provide a mall that satisfies all of the requirements.

[0008]

According to the present invention, there is provided a metal core having a concave portion extending longitudinally on the surface side, a convex portion adjacent to the concave portion , and a molding body tightly fixed to the metal core. The molding body is formed by a hollow injection molding method.
The core metal of the molding body is closely fixed to the core metal.
The hollow thick part is located at the part corresponding to the concave part,
The above problem has been solved by an automobile molding in which a solid thin portion is formed in a corresponding portion .

In this type of automobile molding, a metal core having a concave portion extending in the longitudinal direction on the surface side and a convex portion adjacent to the concave portion is arranged in a mold, and is positioned at one end of the concave portion of the metal core. From the injection port, the molten resin less than the volume in the mold formed by the core metal surface and the mold molding surface is injected into the mold, at the time of injection of the molten resin or after injection of the molten resin, injecting a gas into the filled molten resin in the recess, a hollow thick-walled portion of the automobile molding in correspondence to the recess
Therefore, the solid thin portion is formed corresponding to the convex portion.
Therefore, it is manufactured.

[0010]

By providing a concave portion and a convex portion adjacent to the concave portion on the metal core to form a shape having a large cross section modulus, rigidity against an external force is increased. In addition, the mold may have a simple structure that opens up and down. The flow resistance of the molten resin is increased by adopting the core metal having such a shape, but the inside of the concave portion is formed by forming the molding body tightly fixed to the concave portion as a hollow thick portion by a hollow injection molding method. The flow resistance of the flowing molten resin can be reduced. Molten resin, by injection pressure, and gas pressure injected into it,
It flows exclusively in the recess and spreads in the mold. Since the gas pressure acts uniformly on the molten resin, the outer surface of the molding body corresponding to the recess is pressed into the mold. On the outer surface of the mall body, generation of sink marks, warpage, and the like can be prevented, and a mall having a beautiful appearance can be obtained.

[0011]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. FIG. 1 shows an automobile to which a side molding M1 according to an embodiment of the present invention is attached. 2 to 8 are cross-sectional views including a method of manufacturing the side molding M1 according to the embodiment of the present invention.
FIG. 9 is a sectional view showing a side molding M2 according to another embodiment of the present invention.

FIG. 2 shows a metal core 1 used in the present invention. At the center of the core 1 when viewed from the front side
Is provided with a concave portion 1b, and has two convex portions 1 adjacent to the concave portion.
c, 1c are formed. The core 1 has a concave portion 1b and a convex portion.
By 1c, 1c , the cross section has a shape having a large section modulus. The concave portion 1b and the convex portions 1c, 1c extend in the longitudinal direction of the cored bar. The metal core 1 is bent and formed by a roll forming method or a press forming method. An adhesive N is applied to the upper surface of the cored bar 1.

Next, the core metal 1 is fitted and held in the lower mold 4 in the cavity C of the molds 3 and 4 which are paired up and down as shown in FIG. The core metal 1 is a mold 3 or 4
The shape of the mold is simple because the shape of the mold can be opened up and down. The molding surface 4a of the lower mold 4 is formed so as to be closely fitted to the back surface of the cored bar 1, and the molding surface 3a of the upper mold 3 is formed on the outer surface (decorative surface) of the molding body to be molded. It is formed in a curved shape together.

In FIG. 4, a molten resin P, which is a raw material for molding a molding body, is injected into the surface of the cored bar 1. The molten resin P is filled into the cavity C through an injection port 5 (see FIG. 7) located at one end of the concave portion 1b of the cored bar 1. The injection amount of the molten resin P depends on the surface of the core 1 and the molds 3 and 4.
Is smaller than the volume defined by the molding surfaces 3a and 4a. That is, the molten resin P is not completely filled in the cavity C. As shown in FIG. 4, the molten resin P does not reach both ends in the width direction of the cavity C, and a gap E is left in this portion. Further, the molten resin P has not reached the other end of the concave portion 1b. In this state, an inert gas at an appropriate pressure is injected into the molten resin P injected into the recess 1b. The inert gas is injected in the vertical direction in FIG.

As shown in FIGS. 5 to 7, the inert gas exclusively enters the molten resin P corresponding to the concave portion 1b. The inert gas causes the incompletely filled molten resin P to flow toward the other end of the concave portion 1b, and causes the molten resin P to flow toward the gap E. Recess 1 for improving strength
By flowing the molten resin P using b, the flow resistance of the molten resin P can be significantly reduced.

The pressure of the inert gas acts until the molten resin P is cured. This pressure applies the molten resin P to the core 1
And it acts so as to press against the molding surfaces 3a and 4a. The molten resin P filled in the concave portion 1b becomes relatively thick, and its curing is delayed as compared with other portions. In the concave portion 1b, the shearing force of the molten resin P is small, and the pressure of the inert gas is large in pressing the molten resin P filled in the concave portion 1b against the mold forming surface 3a. In the concave portion 1b, the molten resin P is strongly pressed against the mold molding surface 3a, and the occurrence of defects such as sink marks and warpage on the outer surface of the molding body 2 is prevented.

Then, when the molds 3 and 4 are opened after the molten resin P is cured, as shown in FIGS. 6 and 7, the hollow thick portion 2a corresponding to the elongated concave portion 1b is formed . To the convex part 1c
Correspondingly, a side molding M1 having a solid thin portion 2b is obtained. The side molding M1 is, as shown in FIG.
Double-sided tape T against the door panel D of the car indicated by
Mounted by

In the side molding M1 according to the embodiment of the present invention, a concave portion 1b for improving the strength is provided in the metal core 1, and the concave portion 1b is used as a gas passage in the hollow injection molding method. Since the flow resistance of the molten resin is significantly reduced, long side moldings can also be integrally formed seamlessly, and
Various symptoms such as sink marks and warpage can be eliminated from the outer surface (decorative surface) of the mall body 2.

Next, another embodiment of the present invention will be described with reference to FIG. In this figure, the molding method of the side molding M2 is omitted because it is the same as the above embodiment,
The core metal 11 tightly fixed to the inner peripheral surface of 2 is formed by bending the whole into a hat shape, and is formed at a central portion when viewed from the surface side.
A convex portion 11c is provided, and two concave portions adjacent to the convex portion 11c are provided.
Parts 11b, 11b are formed. Recesses 11b, 11
b and the protruding portion 11c extend in the longitudinal direction of the metal core 11.

In the side molding M2, the concave portions 11b,
The molten resin injected from one end of 11b is mainly injected into the recesses 11b, 11b, and the recessed resin 1b is inert gas.
1b, 11b and to the ends of the recesses 11b, 11b. By the hollow injection molding method described above, the molding body 12
The hollow thick portions 12a, 12a,
12a are formed. In the position corresponding to the convex portion 11c,
The actual thin portion 12b is formed. The bent metal core 11 is
The side molding M2 is given strength to reduce the flow resistance of the molten resin. The pressure of the inert gas is mainly
Since they act on b and 11b, the outer surfaces of the thick portions 12a and 12a are strongly pressed against the molding surface.

Accordingly, the molding body 12 has hollow thick portions 12a formed at both ends in the width direction. However, since the entire thickness is substantially uniform, the width of the molding body 12 is reduced. No sink marks or the like occur on the outer surfaces (decorative surfaces) at both ends in the direction, and the outer surfaces have beautiful outer surfaces (decorative surfaces). Further , a concave portion 11b and a convex portion 11c are provided on the core metal 11.
Because it is, the rigidity of the side molding M2 is increased against an external force. The side molding M2 is attached to the door panel D of the automobile using the double-sided tape T by using the flat portions at both ends in the width direction.
Is fixed by

[0022]

Since the automobile molding according to the present invention has the above structure, it has the following excellent effects. (1) By adopting the core metal having the concave portion extending in the longitudinal direction and the convex portion adjacent to the concave portion , the cross-sectional modulus of the cross section was increased, and the rigidity of the molding was able to be greatly improved. (2) Since the shape of the metal core is such that the metal die can be opened up and down, there is no need to use a complicated and expensive slide die for die-cutting the molding body including the metal core. Is cheaper. (3) Then, this concave portion is hollowed out in the hollow injection molding method.
By using as a thick portion, the flow resistance of the molten resin can be significantly reduced. A long mall or thin
Even a molding having a meat portion can be molded with a lower injection pressure than before. (4) In addition, due to the existence of the hollow portion, the thickness of each part of the molding body does not vary greatly, and the cooling rate of the molten resin is substantially uniform, so that the hollow thick wall on the outer surface (decoration surface) of the molding body. No sink marks, warpage, etc. occur in the portion where the section is provided, and a mall with an elegant appearance can be provided.

According to the second aspect of the present invention, the flow resistance of the molten resin can be reduced by using the concave portion of the core metal as the flow path of the molten resin, and the sink and warp on the outer surface of the molding can be reduced. it can.

[Brief description of the drawings]

FIG. 1 is a perspective view of an automobile to which a side molding M1 according to the present invention is attached.

FIG. 2 is a cross-sectional view of the cored bar 1 used for the side molding M1 of the present invention.

FIG. 3 is a cross-sectional view of a state where the cored bar 1 is fitted into upper and lower dies 3 and 4;

FIG. 4 is a cross-sectional view showing a state in which a cored bar 1 is fitted into upper and lower dies 3 and 4, and a molten resin P is injected and filled while leaving a cavity E in a cavity C.

FIG. 5 is a cross-sectional view of a state in which an inert gas is injected into a molten resin P injected and filled into cavities C of dies 3 and 4, and a hollow portion is formed in a thickest portion.

FIG. 6 is a perspective view of a side molding M1 according to the present invention.

FIG. 7 is a longitudinal sectional view after completion of mold opening of the side molding M1 according to the present invention.

FIG. 8 is a sectional view showing an attached state of the side molding M1 according to the present invention.

FIG. 9 is a sectional view showing an attached state of the side molding M2 according to the present invention.

FIG. 10 is a perspective view of a conventional side molding m1.

FIG. 11 is a perspective view of a conventional side molding m2.

[Explanation of symbols]

M1, M2 Side protector molding (side molding) 1, 11 core metal 1b, 11b concave part 1c of core metal , 12c convex part of core metal 2, 12 molding body 2a, 12a hollow thick wall part 2b, 12b molding body of molding body Solid thin part 3, 4 Mold 5 Injection port

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60R 13/04 B29C 45/00-45/24

Claims (2)

(57) [Claims] A concave portion extending in a longitudinal direction on a front surface side ;
And a core metal provided with a convex portion adjacent to the recess, it and a molding body which is fixed in close contact core metal, the mall present
The body is tightly fixed to the core by a hollow injection molding method,
Hollow in the part of the molding body corresponding to the recess of the cored bar
The thick part has a solid thin part in a part corresponding to the convex part of the cored bar.
An automobile molding, characterized in that a molding is formed. 2. A recess extending in the longitudinal direction on the front side ,
And a metal core having a convex portion adjacent to the concave portion is disposed in a mold, and an injection port located at one end of the concave portion of the metal core is formed by the core metal surface and the mold forming surface. A molten resin smaller than the volume in the mold is injected into the mold. At the time of injection of the molten resin or after the injection of the molten resin, a gas is injected into the molten resin filled in the concave portion, and the thickness of the hollow of the automobile molding is reduced. The meat portion corresponds to the recess,
The actual thin part is formed corresponding to the convex part.
The method of manufacturing the automotive mall.