JPH0952235A - Boss holding structure for resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a low-cost resin molding of high quality without generating a shrink at the molding to mold the molding. SOLUTION: A resin molding is formed by forming substantially sectional U-shaped molding body 17 by a front wall 14 to be formed in a long length, and sidewalls 15, 16 formed from the pair of side edges of the wall 14 in a rearward direction, and further integrally forming a boss 18 for mounting at the suitable position of the one sidewall 15. The rear surface of the wall 14 is coupled to the end of the boss 18 opposed to the rear surface by the rib 10 of a sectional thin mold having a long side in the direction perpendicular to the lengthwise direction of the wall 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boss holding structure which is integrally molded with a resin molded product mounted on a vehicle body such as an automobile and used as a mounting portion when mounted on the vehicle body.

[0002]

2. Description of the Related Art For example, in a vehicle body such as an automobile, it is a general means to attach a kind of decorative member called a molding to the vehicle body as a means for improving the appearance and appearance of the vehicle body.

The molding materials that are commonly used today are
It is a molded product made of synthetic resin, and its surface is, for example, vapor-deposited with aluminum to give it a metallic appearance, and it is expected that the molding member will be attached to the vehicle body to give it a beautiful and luxurious appearance. ing.

As a conventional example of a structure for attaching to a vehicle body provided in such a synthetic resin molding material, there is one disclosed in Japanese Utility Model Publication No. 5-39528, for example.

The synthetic resin molding material disclosed in this conventional example is used for fixing the molding body 1 to the vehicle body at an appropriate position on the back side of the elongated molding body 1 as shown in FIG. The boss portion 2 is made to project integrally with the molding body 1.

As described above, in the molding means for resin-molding the boss portion 2 integrally with the molding body 1, when the cross-sectional area of the joint portion between the boss portion 2 and the molding body 1 is large, when molding the molding resin, At the surface of the molding corresponding to the projecting position of the boss, a sink mark (a dent) is generated during cooling and hardening of the boss portion, which causes a problem that the molding quality of the molding is deteriorated.

[0007]

Therefore, in the above-mentioned conventional example, there is a boss structure as shown in FIG. 6 in order to suppress the occurrence of sink marks and improve the quality. In other words, this boss structure has a shape such that the area of the joint with the end surface of the boss to be joined, especially on the back side of the molding body, is as small as possible, so that the back side of the molding body 1 and the boss portion 2 A cavity portion 3 is formed between them, and a through hole portion 6 for retaining a bank portion 5 is integrally formed on the top wall surface 4 of the molding body 1.

At the time of resin molding of the molding, in order to mold the cavity portion 3 and the bank portion 4,
In addition to the male and female molds that move in the X1 and X2 directions during mold release,
A first slide die that slides in the Y direction to form the through-hole portion 4 and the cavity portion 3 are formed. Therefore, the first slide die slides in the Z direction, which is an intersecting direction with the slide direction. 2 slide type etc. are required, and of course the mold cost increases due to this, and the male and female X
In addition to the moving operation in the X1 and X2 directions, complicated mold closing for operating a plurality of slide molds in the Y direction and Z direction, or the mold opening process increases, the mold equipment becomes complicated, and the equipment cost increases. There was a problem.

Further, in the conventional molding structure, in order to suppress the occurrence of sink marks, the cavity portion 3 is formed between the end surface of the boss portion 2 and the back surface of the molding body 1, and the boss portion is formed. Since the joint cross-sectional shape of the end face and the back surface of the molding body is set to a small semicircular area surrounded by the boss outer peripheral arc and the chord located as far as possible from the boss center point, There is also a problem that the bonding strength between the back surface of the boss and the end surface of the molding body is weak, and due to this, sufficient bonding strength is not obtained between the molding body and the boss portion.

[0010]

SUMMARY OF THE INVENTION The present invention has been made by paying attention to such a conventional problem, and in molding a resin molded product integrally provided with a mounting boss portion, the boss portion of the resin molded product is formed. The first object of the present invention is to produce a high-quality resin molded product that does not cause a sink portion in the corresponding molding portion.

Further, the number of slide molds used for producing the above-mentioned high-quality resin molded products is reduced, and the mold cost and molding equipment are
Further, the second object is to simplify the molding process and obtain a resin molded product excellent in economic efficiency.

As means for achieving each of the above-mentioned objects, in the present invention, by a front wall which is formed to be long and side walls which are formed rearward from a pair of edges of the front wall, A resin molded product in which a molded product main body having a substantially U-shaped cross section is formed, and a mounting boss portion is integrally molded at an appropriate location on the one side wall, the back surface of the front wall and the back surface of the front wall. It is to provide a boss holding structure for a resin molded product, in which a rib having a thin cross section having a long side in a direction orthogonal to the longitudinal direction of the front wall is connected between the facing end faces of the boss portion.

[0013]

According to the present invention, the rib connecting the back surface of the molded product body and the end surface of the boss has a thin cross section, and the short side is made smaller than the long side of the rib to form the rib. Since the coupling cross-section area with the molded product body is set small,
No sink marks are formed on the surface of the molded product body when the ribs are thermally contracted.

Further, the rib has a thin cross section having a long side in a direction perpendicular to the longitudinal direction of the molded product body, and the rib is a single slide type movable in a direction parallel to the long side. It can be molded.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings.

As shown in FIG. 1, the resin molded product of this embodiment is a rectangular frame type molding 13 which is attached to the peripheral edge of the opening of the license plate mounting recess 12 provided on the rear surface of the trunk finisher 11 of the automobile. The molding 13 is made of synthetic resin, and its surface is generally vapor-deposited with aluminum to enhance the metallic appearance and appearance.

As shown in FIGS. 2 and 4, the cross-sectional structure of the molding 13 taken along the line AA is as shown in FIGS. 2 and 4, and includes a front wall 14 extending in the shape of a long strip, and a pair of edges of the front wall 14. Of the molding main body 17 having a substantially U-shaped cross section, which is composed of a pair of upper and lower side walls 15 and 16 formed in the same direction, and is integrally formed at an appropriate position along the longitudinal direction of the upper side wall 14 of the molding main body 17. It has a boss portion 18. This boss part 1
Reference numeral 8 is used to screw the molding 13 to the trunk finisher 11, and a screw hole 20 for a screw screw is formed on the central axis of the boss portion 18.

As is particularly apparent from FIG. 3, the molding main body 17 has vertical ribs 22 corresponding to each boss 18 for increasing the coupling force between the boss 18 and the molding main body 17.
The vertical ribs 20 are formed integrally across the back surface of the front wall 14 and the back surfaces of the upper side wall 15 and the lower side wall 16, and the front side wall 14 of the vertical ribs 22 is formed. The vertical ribs 22 and the boss portion 18 are integrally coupled so that a part of the edge on the opposite side of the boss portion 18 receives the end surface of the boss portion 18. The vertical ribs 22 suppress the occurrence of sink marks at the joints of the ribs 22 with the molding body 17,
The connecting cross-section of the rib 22 and the front wall 14 is set to a rectangular thin section having long sides (a) and short sides (b).

The longitudinal rib 22 having a rectangular cross section is arranged such that its long side (a) is orthogonal to the longitudinal direction of the front wall 14. Reference numeral 21 denotes a die-cutting hole that is formed through the upper side wall 15 and has an opening edge 23 that is flush with the back surface of the front wall 14. The die-cutting hole 21 defines the vertical rib 22. 3 shows a die-cutting hole formed by die-cutting a slide die (not shown) used for molding.

That is, in order to mold the molding 13 with resin, a pair of molding dies including a male mold and a female mold (not shown) are combined with one slide mold for molding the vertical ribs 22, and the molding is performed. As shown in FIG. 4, in the mold releasing step of the molded product (mole) after the resin molding of 13, as shown in FIG.
The mold 13 is obtained by opening the mold in two directions and further pulling out the slide mold in the Y direction.

As described above, according to the molding structure of this embodiment, the boss portion 18 projecting in the back direction of the upper mold 15 is integrally formed with the side wall 15 at an appropriate position in the longitudinal direction of the upper side wall 15 of the molding body 17. Further, in order to further increase the coupling force between the boss portion 18 and the molding body portion 17, a vertical rib 22 is provided between the end surface diameter position of the boss portion 18 and the front wall and the lower wall rear surface of the molding body portion 17. The vertical ribs 22 for connecting the molding body 17 and the boss portion 18 are configured so that the cross-sectional shape of the connection portion is a thin rectangle, and the area of the connection portion is Is small, it is possible to produce a high-quality molding without sink marks during molding molding cooling at the vertical rib connecting portion of the molding main body.

The vertical rib 22 can be formed by a combination of a male die, a female die, and one slide die that moves in a direction orthogonal to the longitudinal direction of the molding body 17, that is, three die members. Therefore, it is possible to mold a molding which is more economical than resin molding which requires the use of a plurality of slide molds as in the conventional example.

[0023]

As described above, according to the present invention, the vertical cross-section of the vertical ribs for connecting the front wall back surface of the resin molded product main body portion and the boss end surface is set to be thin in cross section. Therefore, a good quality resin molded product can be obtained without sink marks on the front wall of the resin molded product.

Further, the ribs move in a direction orthogonal to the longitudinal direction of the molded product body by setting the side orthogonal to the longitudinal direction of the elongated molded product body as the long side of the thin boss. Since the above ribs can be integrally formed by one slide die, the economical efficiency can be improved by reducing the number of dies, closing the dies, and reducing the number of opening dies.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a mounting mode of a resin molded product according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line AA in FIG.

FIG. 3 is a perspective view of a main part showing a boss holding structure according to an embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB in FIG. 3;

FIG. 5 is a perspective view showing a conventional structure.

FIG. 6 is a perspective view of a main part showing a boss holding structure in a conventional molding structure.

[Explanation of symbols]

11 ... Trunk finisher 12 ... Recessed portion 13 ... Mold 14 ... Front wall 15 ... Upper side wall 16 ... Lower side wall 17 ... Mold body 18 ... Boss 19 ... Screw screw 20 ... Screw hole 21 ... Die-cut hole 22 ... Vertical rib 21
… Die-cutting hole 23… Opening edge

Claims (1)

[Claims] 1. An elongated front wall (14), and upper and lower side walls (15) and (16) formed rearward from a pair of edges of the front wall (14), respectively. Due to
A resin molded product in which a molded product main body (17) having a substantially U-shaped cross section is formed, and a mounting boss (18) is integrally projectingly formed at an appropriate portion of the upper side wall (15). The front wall (14) between the back surface of the front wall (14) and the end surface of the boss portion (18) facing the back surface.
A boss-holding structure for a resin molded product, characterized in that the boss-holding structure for a resin-molded product is characterized in that it is joined by a vertical rib (22) having a thin cross-section having a long side in a direction orthogonal to the longitudinal direction of the.