JP3231845B2 - Automotive panels - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle panel suitable for a panel for an outer wall of an engine room.

[0002]

2. Description of the Related Art Panels for automobiles have been successively replaced with iron-based materials such as high-strength steel or non-ferrous materials such as aluminum or plastics. In general, plastics are made by injection molding thermoplastic resin, but due to insufficient rigidity, a method of separately forming a skin located on the outside of the vehicle body and a stiffener located on the inside, and then bonding these. Is adopted. Alternatively, a method of setting a stiffener formed in advance with a stampable sheet in a mold and injecting a thermoplastic resin into the stiffener to form a skin is employed. In any case, since the stiffener projects in the direction perpendicular to the plane of the skin, the bending rigidity and the torsional rigidity are dramatically increased.

[0003]

However, each of the above-mentioned methods relating to plastics requires two molding steps, so that the production cycle time becomes longer, and there is a problem in terms of mass production and cost.

Further, rigidity can be increased by separating the stiffener from the skin to some extent. For example, when the stiffener is exposed to the outside air and the stiffener is exposed to a high-temperature engine room, the stiffener side undergoes a large thermal expansion, so that the entire body is expanded. As a concave surface.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automobile panel that can withstand a temperature difference between the outer and inner surfaces despite the shortening of the molding process.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a vehicle panel having a hollow double-walled structure formed by a synthetic resin blow molding method, wherein one wall of the panel is connected to the other wall. Wall is filled with synthetic resin in fiber or flake form
By mixing more material, a small thermal expansion coefficient is obtained.

This automobile panel is suitable for an engine room outer wall panel in which a wall having a large coefficient of thermal expansion faces the outside air and a wall having a small coefficient of thermal expansion faces the engine room.

[0008]

For example, even if the temperature of the engine room rises, the amount of expansion of the inner side wall is small, so that there is no possibility that the entire surface becomes concave.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals.
FIG. 1 is a plan view of an automobile panel according to the present invention, and FIG. 2 is a sectional view taken along line 2-2 of FIG. If the automobile panel 1 is described using a bonnet as an example, the automobile panel 1 is characterized by having a hollow double-walled structure formed by a synthetic resin blow molding method, and corresponds to one wall as shown in FIG. This is a structure in which a skin 2 on the outside of the vehicle body and a stiffener 3 on the inside of the vehicle body corresponding to the other wall are integrally formed.

More specifically, the five projecting ribs 4 to 4 shown in FIG.
8 and a plurality of conical ribs 9 project from the stiffener 3, and their tips are fused to the slightly curved planar skin 2. The five ridge ribs 4 to 8 form a box together with the skin 2 and the stiffener 3 to increase rigidity, and the conical ribs 9... Serve as resistance members against a compressive load in a direction perpendicular to the plane of the skin 2. Are hollow members with high rigidity. In the present embodiment, the ridge ribs 4 to 8
Is a U cross section, but is not limited to this, and may be a V cross section, for example.

The skin 2 is made of ABS, PPO (polyphenylene oxide), PC (polycarbonate), PB
T (polybutylene terephthalate), PA (polyamide) or the like, or a synthetic resin material such as a polymer alloy obtained by compounding them, while the stiffener 3 is a fiber or flake-like filler in the same synthetic resin as the skin. It is characterized in that it is mixed in a larger amount than the skin 2 and has a lower linear expansion coefficient than the skin 2. Filler is whisker such as glass fiber, alanide fiber, carbon fiber, potassium titanate, etc.
Glass flakes and mica are preferred. However, talc or the like having a spherical shape or a shape close to a sphere is not preferable because the effect of lowering the linear expansion coefficient is small. Also, by reducing the amount of filler such as glass fiber on the skin side compared to the stiffener, the appearance of the skin can be kept good.

A method of manufacturing the vehicle body panel having the above-described structure will be described below. FIG. 3 is a sectional view of a main part of a blow molding apparatus according to the present invention. The apparatus has a first mold 12 in which a recess 11 for a skin 2 is cut and a recess 13 for a stiffener 3. A second mold 14 provided, rams 15 and 16 for bringing the molds 12 and 14 into and out of contact with each other, and a first nozzle 17 and a second nozzle 18 provided downward at predetermined and isolated positions. Consists of The first and second nozzles 17,
Reference numeral 18 denotes an elongated slit nozzle extending in the front and back directions of the drawing.

The second mold 14 has projections 14a, 14b, 1 for forming the protruding ribs 4, 5, 6 shown in FIG.
4c is engraved, and although not shown, a convex portion corresponding to the conical rib 9 is also engraved. The first nozzle 17 is a nozzle for extruding a synthetic resin for the skin 2, and the second nozzle 18 is an extruder for a synthetic resin in which a filler such as glass fiber is mixed in a larger amount than the skin 2 for the stiffener 3. Nozzle.

Each synthetic resin is extruded downward from the first nozzle 17 and the second nozzle 18.
Since 18 communicates only at the front and rear ends in FIG. 3, the extruded synthetic resin has a very flat cylindrical shape in plan view. Such a bag of synthetic resin before blow molding is called parison B.

FIGS. 4 (a) to 4 (f) are flow charts of blow molding according to the present invention, and FIG. 4 (a) shows a state in which preparation is completed and parison extrusion is started. In FIG. 4B, a parison B formed by extruding each synthetic resin from the first and second nozzles 17 and 18 has a lower end sandwiched by a lower pre-pinch 19. FIG. 4C shows a step (pre-blow) of slightly expanding the parison B in preparation for the next mold clamping, in which a needle-shaped blow pin (not shown) is inserted into the parison B,
An appropriate amount of high-pressure air or high-pressure inert gas is sealed. Next, the mold is lightly clamped in FIG.
In FIG. 4E, the mold is sufficiently clamped, high-pressure air or high-pressure inert gas is blown, and the parison B is pressed against the concave portions of the first and second molds 12 and 14 with this pressure to form the skin and the stiffener. . 4F, the pressurization is completed, the first and second molds 12, 14 are opened, and the molded product is taken out. Thus, the vehicle body panel 1 shown in FIGS. 1 and 2 is obtained.

If the car panel 1 shown in FIG. 2 has the large thermal expansion coefficient side wall or skin 2 facing the outside air, and the small thermal expansion coefficient side wall or stiffener 3 faces the engine room, the engine room can be obtained. Stiffener 3 even when the temperature rises
Since the amount of thermal expansion is small, there is no need to worry about a concave surface as a whole. Therefore, the vehicle panel 1 is suitable for an engine room outer wall panel.

[0017]

FIG. 5 is a view showing another embodiment of FIG. 3. This device has almost the same configuration as the device described in FIG. 3, and has a first mold 22 in which a concave portion 21 for the skin 2 is formed. And a second mold 2 in which a concave portion 23 for the stiffener 3 is engraved.
4 and a ram 2 for bringing the molds 22 and 24 into and out of contact.
5 and 26, and a first nozzle 27 and a second nozzle 28 provided downward at a position separated by a certain distance. First
The second nozzles 27 and 28 are both elongated slit nozzles extending in the front and back directions of the drawing, but eject the sheets S1 and S2 unlike FIG. Reference numerals 24a to 24c are the same convex portions as those of the aforementioned 14a to 14c.

In the apparatus shown in FIG. 5, the sheet S1 is ejected downward from the first nozzle 27 and the sheet S2 is ejected downward from the second nozzle 28. Next, the molds 22 and 24 are put together and the sheets S1, S2
Are partially joined, and then a high-pressure gas is sealed in the sheets S1 and S2, and the sheets are inflated to obtain a blow molded body. According to such a sheet forming method, a flat formed body such as an engine room outer wall panel can be easily obtained, and the thermal expansion coefficients of the skin and the stiffener can be easily changed.

That is, the automobile panel 1 of the present invention can be manufactured by any of the parison blow molding method described in FIG. 3 and the sheet blow molding method described in FIG.

The vehicle body panel 1 of the present invention may be used for a trunk lid or a roof in addition to a panel for an engine room outer wall.

[0022]

As described above, according to the present invention, since the automobile panel has a hollow double-walled structure by a blow molding method of a synthetic resin, only one process is required, so that the mass production effect is enhanced and the cost can be reduced.

Since one wall of the panel has a different coefficient of thermal expansion with respect to the other wall, for example, even if the temperature of the engine room rises, the amount of expansion of the inner wall is small. There is no danger of becoming concave.

[Brief description of the drawings]

FIG. 1 is a plan view of an automotive panel according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view of a main part of the blow molding apparatus according to the present invention.

FIG. 4 is a process chart of blow molding according to the present invention.

FIG. 5 is a view showing another embodiment of FIG. 3 according to the present invention;

[Explanation of symbols]

1 ... car panel, 2 ... skin (one wall), 3 ... stiffener (the other wall).

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 49/00-49/80 B62D 25/00-25/22

Claims (2)

(57) [Claims] An automotive panel having a hollow double-walled structure formed by a synthetic resin blow molding method, wherein the panel has one wall and the other wall made of synthetic resin such as fibers or flakes.
An automotive panel characterized by having a small coefficient of thermal expansion by incorporating more filler in the shape of a metal . 2. The vehicle panel according to claim 1, wherein the automobile panel is a panel for an outer wall of an engine room in which a wall having a large coefficient of thermal expansion faces the outside air and a wall having a small coefficient of thermal expansion faces the engine room. The automotive panel according to claim 1.