JPH11189106A - Roof mole for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roof mole for a vehicle which does not generate thermal deformation even when it is completely fixed to a connecting part, nor needs a smoothing treatment and a painting finish, because a surface including a strengthening material after molding is smoothed. SOLUTION: A roof mole for a vehicle comprises a core layer composed of a synthetic resin core material including a strengthening material and a skin layer composed of a synthetic remit skin material and forming a surface layer by surrounding the core layer. The coefficinet of linear expansion of the core material is set to be smaller than that of the skin material. The core material and the skin material are injected at the same time, and the same sprue and the same cavity are completely filled with these materials flowing in layers. After that, the materials are molded by cooling and solidifying them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile roof molding for covering a joint between a central roof panel and a side roof panel of an automobile.

[0002]

2. Description of the Related Art For example, as shown in FIG. 1, a joint portion between a center roof panel 1 and a side roof panel 2 of an automobile includes:
The roof molding 3 is fitted. The roof molding 3 is mainly formed of a synthetic resin material in response to demands for weight reduction and cost reduction, and has a function of improving the aesthetic appearance of the automobile and preventing raindrops by covering a welded portion of the joint. . However, these synthetic resin roof moldings 3
However, there is a problem in that the heat expansion and contraction greatly due to a temperature change outside the vehicle (−40 to 100 ° C.) causes easy deformation when the joint is completely fixed using bolts or the like.

In order to avoid such deformation of the roof molding 3, a special structure is adopted in which the roof molding 3 is attached to a joint, instead of being completely fixed by bolts or the like, it can be slightly moved in the longitudinal direction. Structures are often employed. However, such a roof molding has a problem that the number of parts increases and the manufacturing cost increases, and the appearance of the front and rear end portions of the vehicle body deteriorates due to thermal expansion and contraction of the roof molding.

[0004]

Therefore, as means for suppressing the thermal expansion and contraction of the roof molding, it is conceivable to use a metal such as stainless steel as a core, or to mix a reinforcing material such as glass fiber into a synthetic resin. . However, this is contrary to the demands for weight reduction and cost reduction, and the surface of the molded product becomes rough, and a considerable cost is required for smoothing treatment by sanding and the like and painting finish.

[0005] The present invention has been made in view of such a situation, and by devising so that the surface after molding is smooth while containing a reinforcing material in the material, even if it is completely fixed to the joint, thermal deformation is prevented. It is an object of the present invention to provide an automobile roof molding which does not occur and does not require a smoothing process and a paint finish.

[0006]

Means and Action for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result,
A core layer made of a synthetic resin containing a reinforcing material such as glass fiber and having excellent mechanical strength and dimensional stability; and a skin layer made of a synthetic resin not containing the reinforcing material and having excellent appearance and weather resistance. The present inventors have found that a layer structure does not cause deformation even when completely fixed to a vehicle body using stud bolts or the like, and that the smoothing process and the painting finish can be omitted, and the present invention has been completed.

That is, the present invention comprises a core layer made of a synthetic resin core material containing a reinforcing material, and a skin layer made of a synthetic resin skin material and surrounding the core layer to form a surface layer. By setting the coefficient of linear expansion of the core material to be smaller than the coefficient of linear expansion of the skin material, simultaneously injecting the core material and the skin material, flowing the same sprue and the same cavity in a layered manner, and completing cooling and solidifying by cooling. An automobile roof molding characterized by being molded. In such a roof molding, thermal expansion and contraction due to a temperature change outside the vehicle is suppressed and a smooth surface is obtained. Therefore, even if it is completely fixed to the joint between the center roof panel and the side roof panel, it does not deform and keeps excellent weather resistance and beautiful appearance, smoothing treatment and painting finish can be omitted, and the degree of freedom in structural design can be reduced. The manufacturing cost can be greatly reduced as the number increases.

Here, the coefficient of linear expansion of the core layer is 1 to 6 ×
10 ⁻⁵ / ° C., and the coefficient of linear expansion of the skin layer is 3 to 10 ×.
Preferably it is 10 ^-5 / ° C. As a result, the linear expansion coefficient of the entire roof molding can be suppressed to the range of 2 to 7 × 10 ⁻⁵ / ° C., and an automobile roof molding with little thermal expansion and contraction can be obtained.

Further, a blowing agent is added to the core material in an amount of 3 to 10 w
It is preferable that the filling is completed by foaming of the core material by adding t%. In this case, sinking of the thick portion due to cooling is prevented, dimensional stability is improved, and impact resistance and cold resistance of the roof molding are also improved.

[0010] Further, the ratio of the skin material to the whole material is preferably 10 to 90 wt%. As a result, the surface of the roof molding becomes smooth, and the thin portion such as the mounting portion is filled with the material without interruption.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the details of the present invention will be described with reference to the embodiments shown in FIGS. Automotive roof molding 3
As shown in FIG. 2, the decorative head 5 and the reinforcing member 9 each having a substantially C-shaped cross section are main components of the decorative head 5. As shown in FIGS.
And a cylindrical mounting base 12 for mounting the reinforcing member 9 on the lower surface of the decorative head 5 with bolts 11 in the longitudinal direction of the decorative head 5. Are provided at predetermined intervals. To attach the roof molding 5 having the above-described structure, a double-sided tape 13 is attached to the lower surface of the reinforcing member 9, and the stud bolt 7 to be fixed to the attaching member 6 is inserted through the center roof panel 1 and the side roof panel 2. 10 and completely fixed by tightening with a nut 8 from the room.

In this manner, the roof molding 3 is completely fixed to the mounting groove 4 by using the stud bolt 7 and the double-sided tape 13, and as shown in FIG. 9, the vertical section becomes cylindrical,
It has mechanical strength that could not be achieved with conventional complex mounting structures.

As shown in FIGS. 4 to 6, it is preferable to raise the edge of the central roof panel 1 in order to apply the sealing material 15 to the joint between the central roof panel 1 and the side roof panel 2. .

As shown in FIG. 7, the decorative head 5 has a core layer 16 made of a synthetic resin core material containing a reinforcing material.
And a skin layer 17 made of a synthetic resin skin material having excellent weather resistance and a beautiful appearance and surrounding the core layer 16 to form a surface layer. The thickness is 2.0 to 15 mm, preferably 3.0 to 3.0. It has a two-layer structure of 5.0 mm. With this two-layer structure, a foaming core material and a non-foaming skin material are simultaneously injected by one molding machine, and the same sprue and the same cavity are layered and flown. The filling is completed by foaming the core material. Then, it is molded by cooling and solidifying. Since a smooth glossy surface is obtained on the surface of such a molded product, painting finish of the molded product can be omitted by coloring the skin material in advance.

Further, in order to prevent sink marks occurring in the thick portion of the decorative head 5, a foaming agent such as nitrogen gas is added to the core material. Generally, when a synthetic resin material is filled in a cavity while foaming, a rough surface called a swirl mark occurs on the surface of a molded product. In the present invention, since the non-foamed skin material is simultaneously injected to form the surface layer, the occurrence of the swirl mark can be prevented. In addition, since the foaming gas generated inside the decoration head 5 is blocked by the dense skin layer and is not released to the surface, even in the case of finishing the coating, the degassing step by heat treatment or the like can be omitted.
It can be sent to the painting process immediately after molding. If the amount of the foaming agent is 10 wt% or more, the core material exhibits high fluidity, and laminar flow with the skin material becomes impossible.
If it is less than t%, sink marks occur in the thick part of the molded product.
Therefore, the amount of the foaming agent is preferably 3 to 10% by weight.

The thickness of the formed skin layer becomes smaller as the flow resistance in the cavity becomes larger and as the distance from the gate increases. Therefore, if the skin material accounts for less than 10% by weight of the entire material, the molding material is not filled into the details of the mounting member when the mounting member 6 and the like are integrally formed, and the surface of the decorative head 5 is not covered. No longer smooth.
The ratio of the skin material to the entire material is 90 wt%.
If it is above, the linear expansion coefficient of the decoration head 5 whole will increase,
It is easily deformed. Therefore, the ratio of the skin material to the whole material is set to 10 to 90 wt%, but 50 to 70 wt%.
It is more preferable to balance the smoothness of the surface and the coefficient of linear expansion as wt%.

For example, the decorative head 5 is made of a core layer composed of a core material containing short fibers of glass fibers in a mixture of PC (polycarbonate) and PBT (polybutylene terephthalate), and a skin material which is a mixture of PC and PBT. And a core layer having a linear expansion coefficient of 3
× 10 ⁻⁵ / ° C., the coefficient of linear expansion of the skin layer is set to 7 × 10 ⁻⁵ / ° C., and the ratio of the skin material to the whole material is 30.
When it is set to ４０40%, the linear expansion coefficient of the entire decorative head 5 is 5 ×
10-5 / ° C. As described above, when the linear expansion coefficient of the decorative head 5 is reduced, a stable automobile roof molding with less thermal expansion and contraction can be obtained. Therefore, it is not necessary to adopt a complicated mounting structure that can be freely moved by thermal expansion and contraction. The mounting groove 4 is formed by using the stud bolt 7 as in this embodiment.
And the mechanical strength and the mounting strength can be increased by using the reinforcing member 9. In addition, the reinforcing material such as glass fiber contained in the core layer of the decorative head 5 has the effect of suppressing the linear expansion coefficient of the core layer.
Because it has the effect of reinforcing material to increase the rigidity of
There is no need to provide a reinforcing rib or the like on the lower surface of the decorative head 5, so that weight reduction and cost reduction can be achieved.

As the reinforcing material used in the present invention, carbon fibers can be used in addition to glass fibers. In this case, a core layer having higher hardness and higher elasticity can be obtained. It is also possible to reduce the material cost by adding a filler such as wood flour to the core material. Further, it is also effective to add a coloring agent to the skin material to impart coloring and light resistance to the roof molding.

Finally, Table 1 shows combinations of core materials and skin materials suitable for the roof molding for automobiles of the present invention. However, the core material contains glass fiber short fibers as a reinforcing material and contains a foaming agent at 10 wt% or less.

[0020]

[Table 1]

In Table 1, PC is polycarbonate, PBT is polybutylene terephthalate, ABS is A
BS resin, PET is polyethylene terephthalate, AE
S is AES resin, ASA is ASA resin, and PP is polypropylene.

According to the roof molding for an automobile of the present invention as described above, a core layer made of a synthetic resin core material containing a reinforcing material, and a core layer made of a synthetic resin skin material are surrounded by the core layer. It is composed of a skin layer forming a surface layer, and the coefficient of linear expansion of the core material is set to be smaller than the coefficient of linear expansion of the skin material, so that thermal expansion and contraction is suppressed and a smooth surface is obtained. Even if completely fixed, it does not cause deformation, maintains weather resistance and beautiful appearance, can omit smoothing treatment and painting finish, increases the degree of freedom in structural design, and can significantly reduce manufacturing cost. In this case, by setting the linear expansion coefficient of the core layer to 1 to 6 × 10 ⁻⁵ / ° C. and the linear expansion coefficient of the skin layer to 3 to 10 × 10 ⁻⁵ / ° C.,
The linear expansion coefficient of the entire roof molding is 2 to 7 × 10 ⁻⁵ / ° C., and thermal expansion and contraction can be suppressed.

Also, a foaming agent is added to the core material in an amount of 3 to 10% by weight.
By adding the core material, foaming of the core material completes the filling of the core material and the skin material into the cavity, and prevents sinkage of a thick portion due to cooling to improve dimensional stability. Cold resistance can be imparted.

Further, by setting the ratio of the skin material to the entire material to be 10 to 90 wt%, the surface of the roof molding can be kept smooth, and the material can be filled into a thin portion such as a mounting portion without any delay.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a use state of a roof molding for an automobile.

FIG. 2 is an exploded perspective view showing an automobile roof molding according to a typical embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2 in a state where a roof molding for an automobile is assembled.

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

FIG. 5 is a sectional view taken along line CC in FIG. 3;

FIG. 6 is a sectional view taken along line DD in FIG. 3;

FIG. 7 is a sectional view of the decorative head showing a two-layer structure of a core layer and a skin layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Central roof panel 2 Side roof panel 3 Roof molding for automobiles 4 Mounting groove 5 Decorative head 6 Mounting member 7 Stud bolt 8 Fastening nut 9 Reinforcement member 10 Hole 11 Bolt 12 Mounting base 13 Double-sided tape 14 Washer 15 Sealing material 16 Core layer 17 Skin layer

Claims (4)

[Claims] 1. A core layer made of a synthetic resin core material containing a reinforcing material, and a skin layer made of a synthetic resin skin material and surrounding the core layer to form a surface layer. The coefficient of linear expansion is set to be smaller than the coefficient of linear expansion of the skin material, and the core material and the skin material are simultaneously injected,
An automobile roof molding characterized by being formed by laminar flow in the same sprue and the same cavity, and after completion of filling, solidification by cooling. 2. The linear expansion coefficient of the core layer is 1 to 6 × 10 ^−5.
/ ° C, and the coefficient of linear expansion of the skin layer is 3 to 10 × 10 ^−5.
The roof molding for an automobile according to claim 1, wherein the roof molding is set to / ° C. 3. A blowing agent is added to the core material in an amount of 3 to 10% by weight.
The roof molding according to claim 1 or 2, wherein the addition is completed by foaming the core material to complete the filling. 4. The automobile roof molding according to claim 1, wherein a ratio of the skin material to the whole material is set to 10 to 90 wt%.