JPH10129357A - Integrated roof rail for vehicle and molding method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish an economical simple manufacturing process and production of a coupling part by molding a leg part and a rail part integrally of thermoplastic resin by means of injection molding. SOLUTION: A thermoplastic resin composed of a polyamide resin composition, in which a blend or a copolymer of polyamide such as aide resin consisting of a hexamethylenediadipamide unit prepared from adipic acid and hexamethylenediamine and a hexamethyleneisophthalamide unit prepared from isophtalic acid and hexamethylenediaimne is filled with inorganic filler such as glass fiber so as to be reinforced, is molded into a leg part 1 and a rail part 2, in which a hollow part 3 is formed, integrally by means of injection molding. As a result, production is facilitated and reduction of weight and improvement in dimension stability and in an appearance can be accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vehicle roof rail mounted for loading on a vehicle roof.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a roof rail has a leg 1 and a rail 2 as separate parts, and the leg 1 and the rail 2 are separately manufactured and assembled.
It is also common to mount it on the roof of a vehicle. Further, in the conventional roof rail, the rail portion 2 is a deformed tubular body made of metal, and the leg portion 1 attached to the rail portion 2 is provided.
Is generally a metal die-cast product. It is also known that the roof rail leg 1 is made of a synthetic resin (Japanese Patent Laid-Open No. 8-2336). However, since the load is applied and a large dynamic load is applied during traveling of the vehicle, at least The rail portion 2 is mostly made of metal in order to obtain sufficient strength.

[0003]

However, it is necessary to reduce the weight of the vehicle in order to meet the demands for energy saving and improved fuel efficiency. In order to provide a lightweight roof rail corresponding to this, a metal rail portion must be provided. Not preferred. Also, with conventional roof rails that are assembled after the legs and rails are separately manufactured, special attention is needed for the strength of the connection between the legs and rails, which requires complicated manufacturing processes and connection and assembly. Therefore, there is also a demand for a manufacturing method that requires a large production burden, and is economical and simple.

[0004]

SUMMARY OF THE INVENTION The present invention satisfies the demands for improvement such as reduction in weight of a roof rail and simplification of production.
The present invention has been completed by the present inventors finding out that this can be achieved by forming the leg portion and the rail portion into an integral injection-molded product of a thermoplastic resin.

That is, the invention according to claim 1 is an integrated roof rail for a vehicle, which is an injection-molded product of a thermoplastic synthetic resin in which a foot portion and a rail portion for attachment to a roof of a vehicle are integrated. It is. Further, the invention of claim 1 is intended to obtain good strength, appearance, dimensional accuracy and the like of a product.
It is preferable to be composed of a specific thermoplastic resin,
Further, it is preferable to have a specific hollow structure.

The invention according to claims 4 and 5 is a method for manufacturing an integrated roof rail for a vehicle having the above specific hollow structure. The invention according to claim 4 is directed to a subcavity having a volume corresponding to 15 to 75% of the total volume of the rail portion. After using a mold connected to a cavity for molding the legs and rails through a passage, and injecting and filling a thermoplastic resin into the cavity, pressurized gas is injected into the main cavity, A method for forming a roof roof rail for a vehicle, wherein the molding is performed by hollow injection molding for extruding a thermoplastic resin in a cavity into a sub-cavity. The volume of the cavity for molding the rail is 15 to 75% of the total volume of the rail.
Injecting and filling thermoplastic resin into the cavity before expanding the volume using a mold that can be expanded by the amount corresponding to the volume, and then molding by hollow injection molding to pressurize the pressurized gas into the cavity and expand the cavity volume A method for forming an integrated roof rail for a vehicle, characterized by the following features.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an integrated roof rail for a vehicle according to the present invention comprises a leg portion 1 and a rail portion 2 integrally formed by injection molding of a thermoplastic resin. It is.

In the example shown in FIG. 1, three legs 1 are provided at both ends and a center portion of one rail portion 2, but the number of legs 1 in the present invention is It is determined from the safety factor based on the load weight required for the integrated roof rail for vehicles and the permissible limit of the assumed dynamic load. The number is not particularly petitioned, and the shapes of the leg 1 and the rail 2 are not limited to the present invention. There is no limitation unless it deviates from the purpose.

The thermoplastic resin constituting the integrated roof rail for vehicles of the present invention includes, for example, polyamide resin, polypropylene resin, ABS resin, AS resin, AES resin, and the like.
Polycarbonate resin, PBT resin, PET resin, PP
An S resin, a PPE resin, a blend thereof, a mixture of these with an additive, a filler, and the like can be used.

Among the above thermoplastic resins, lactam polyamides, aliphatic polyamides comprising diamines and dibasic acids, aromatic polyamides starting from isophthalic acid, terephthalic acid, meta-xylylenediamine and the like, and furthermore, these polyamides Blends and copolymers with at least one inorganic filler selected from glass fiber, carbon fiber, milled fiber, mica, talc, kaolin, wollastonite, calcium carbonate, magnesium oxide, potassium titanate, etc. Is used. A polyamide resin composition reinforced with 25% by weight or more is used, and is preferably 35% by weight or more from the viewpoint of moldability and strength and dimensional stability which are one of the objects of the present invention.

In general, even among inorganic fillers, the appearance of a product made of a resin composition filled with a large amount of a fibrous filler such as glass fiber is such that the filler easily emerges on the product surface.
Deterioration in appearance such as gloss is likely to occur. From such a problem, in order to achieve the same appearance requirement as a conventional metal roof rail, among the polyamide resins, Japanese Unexamined Patent Publication No.
No. 8, using a polyamide resin comprising a hexamethylene diadipamide unit obtained from adipic acid and hexamethylene diamine and a hexamethylene isophthalamide unit obtained from isophthalic acid and hexamethylene diamine. It is most preferable to use a polyamide resin containing 5 to 30% by weight of hexamethylene isophthalamide unit.

In the integrated roof rail for a vehicle according to the present invention, even if the rail portion 2 is in a so-called solid state, a reduction in weight and improvement in manufacturing can be achieved as compared with a conventional roof rail in which the leg portion 1 and the rail portion 2 are assembled. However, in order to further improve the economical efficiency such as weight reduction and molding in a short time, and to improve the dimensional stability of the molded product, the total volume of the rail portion 2 of the integrated roof rail for a vehicle of the present invention is 15 to 15 or less. It is desirable to form 75%, preferably 15 to 50%, of the hollow portion 3. 15%
In the following, the effect of improving economical efficiency such as weight reduction and molding in a short time is small, and if it is 75% or more, the rail portion 2 is easily bent when loaded, or the rail portion 2 is easily damaged by a dynamic load during running of the vehicle. Cheap.

The hollow portion 3 of the integrated roof rail for a vehicle according to the present invention is formed in the rail portion 2. However, as long as the performance of the integrated roof rail for a vehicle is not impaired, a part of the leg portion 1, for example, the appearance of the leg portion 1 is improved. The hollow portion 3 can be formed for the purpose.

The formation of the hollow portion 3 can be exemplified by, for example, Japanese Patent Publication No. 57-14968.
It can be performed by so-called hollow injection molding. That is, a thermoplastic resin melt-plasticized by an injection molding machine is injection-filled into a cavity of a mold, and is manufactured by an apparatus for manufacturing a high-pressure gas, and is generally inert gas such as high-pressure nitrogen gas of 50 kg / cm ² or more. Injecting gas into the molten resin in the cavity while controlling the gas with an injection device, holding pressure, cooling, releasing the gas injected into the resin, opening the mold, and taking out the product. it can.

What is important in forming the hollow portion 3 is to form the hollow portion 3 as uniform as possible from the viewpoint of strength and dimensional stability. The hollow portion 3 can be formed simply by injecting an inert gas such as high-pressure nitrogen into the molten resin injected and filled in the cavity of the mold. However, when the amount of the molten resin to be filled in the cavity is large, Is the hollow part 3
Is partially formed, and a difference in the amount of shrinkage between the portion where the hollow portion 3 is formed and the solid portion may cause a problem in appearance such as a difference in size and sink marks. Further, when the amount of the molten resin to be filled in the cavity is small, the hollow portion 3 is formed almost entirely, but depending on the reinforced resin used, the reinforced material may float on the product surface, resulting in deterioration of the appearance. is there.

A method for forming a uniform hollow portion 3 having a good appearance and a stable strength and dimensions will be described below.

In the first method, as shown in FIG. 2A, a sub-cavity 4 having a volume corresponding to 15 to 75% of the total volume of the rail portion 2 is formed, and the leg portion 1 and the rail portion 2 are formed. This is a method using a mold provided to be connected to the main cavity 5 through the passage 6.

First, as shown in FIG. 2B, the cavity 5 is filled with a molten thermoplastic resin by injection. Injection of the molten resin is preferably performed until the cavity 5 is filled in order to obtain a good product appearance. At this time, in order to prevent a large amount of molten thermoplastic resin from entering the sub-cavity 4,
It is also possible to provide a pin or a valve (not shown) for opening and closing the passage 6, and close this.

Next, as shown in FIG. 2 (c), the gas was produced by an apparatus for producing a high-pressure pressurized gas.
An inert gas such as a nitrogen gas of not less than kg / cm ² is injected into the molten resin in the main cavity 5 from a gas injection position while controlling with an injection device. At this time, if the above pins and valves are provided in the passage 6, they are kept open. As the pressurized gas is injected, a part of the molten resin in the cavity 5 is extruded into the sub-cavity 4 through the passage 6, and a substantially uniform hollow portion 3 is formed in the resin in the cavity 5. Become. In addition, the volume of the sub cavity 4 is
The volume of the hollow portion 3 to be formed can be set to 15 to 75% of the total volume of the rail portion 2 by setting the volume corresponding to 15 to 75% of the total volume of the rail portion 2.

The connection position of the sub-cavity 4 and the press-fitting position of the pressurized gas are determined by connecting the sub-cavity 4 to one end of the cavity portion of the main cavity 5 where the rail portion 2 is formed, and pressurizing the other end. It may be the gas injection position,
In forming the hollow portion 3 as uniformly as possible in the rail portion 2, sub-cavities 4 are connected to both ends of the cavity portion for forming the rail portion 2, and the center of the cavity portion for forming the rail portion 2 is pressurized gas. It is preferable to set the press-fitting position. In this case, the hollow portion 3 can be formed only in the rail portion 2. However, if the sub-cavity 4 is connected to the cavity portions for molding the leg portions 1 at both ends, the hollow portion 3 is formed in a part of the leg portion 1.
Can be formed.

When a pin or valve capable of opening and closing the passage 6 is provided, the molten plasticized resin is injected and filled into the cavity in a state where the pin or valve closes the passage 6, and simultaneously with or after the completion thereof. Before, simultaneously with, or after the start of the injection of the high-pressure gas, the pin or the valve is opened, and a part of the molten resin in the cavity 6 is guided to the sub-cavity 7. Here, the opening / closing operation of the pin or the valve is operated by a drive source such as a hydraulic or pneumatic cylinder based on an electric signal or the like from the injection molding machine and a pressurized gas injection device, but the method is not particularly limited. Not something.

In the second method, as shown in FIG. 3A, a cavity 5 for molding the leg 1 and the rail 2 is provided.
This is a method using a mold that can increase the volume of the cavity for molding the rail 2 by an amount corresponding to 15 to 75% of the total volume of the rail 2. In the illustrated mold, the movable section 7 is retracted so that the cavity volume can be increased.

First, as shown in FIG. 3B, a molten thermoplastic resin is injected and filled into the cavity 5 before the expansion of the volume. Injection of the molten resin is preferably performed until the cavity 5 is filled in order to obtain a good product appearance.

Next, as shown in FIG. 3 (c), the pressure was generally increased by 50% using an apparatus for producing a high-pressure pressurized gas.
An inert gas such as a nitrogen gas of not less than kg / cm ² is injected into the molten resin in the main cavity 5 from a gas injection position while controlling with an injection device. Before or simultaneously with the press-in of the pressurized gas, or simultaneously with the start of the press-in, when the movable portion 7 is retracted to increase the cavity volume, the pressurized gas is press-fitted along with the expansion, and the volume corresponding to the expanded volume is increased. Is formed in the rail portion 2.

The movable section 7 is driven by a hydraulic or mechanical operation mechanism or the like based on an electric signal or the like from an injection molding machine and a pressurized gas injection device, but the method is not particularly limited. .

[0026]

EXAMPLES The present invention will be described below with reference to examples, but the examples are illustrative of the present invention and do not limit the present invention.

Example 1 Using a mold having the structure shown in FIG. 2A, the vehicle integrated roof rail shown in FIG. 1 was mixed with 55% glass fiber and had a flexural modulus of 160,000 kg / cm ² and hexamethylene.ヘ キ サ 10% by weight of hexamethylene isophthalamide unit composed of adipamide unit and hexamethylene isophthalamide unit
Was molded with a 650-ton injection molding machine equipped with a pressurized gas injection device for hollow injection molding manufactured by Asahi Engineering Co., Ltd. using the above polyamide resin. The resin melt-plasticized at 295 ° C.
After filling the mold in an amount that fills the cavity of the mold whose temperature has been adjusted to 0 ° C., after 0.5 seconds, the opening / closing pin installed in the passage leading to the sub-cavity having a volume of 45% of the volume of the cavity for molding the rail portion is mounted on the hydraulic mechanism. , The passage was opened, and nitrogen gas of 120 kg / cm ² was injected from the pressurized gas injection device into the molten resin in the cavity for 10 seconds. Thereafter, the temperature was held for 30 seconds to complete the cooling, and after the injected gas was released to the atmosphere, the mold was opened and the molded product was taken out. The hollow state of the rail part of the molded roof rail for vehicles is
45% of the rail volume, good appearance, strength,
The object of the present invention was satisfied in terms of weight.

Embodiment 2 Using a mold having the structure shown in FIG. 3A, filling the molten resin in the cavity state before the volume expansion as shown in FIG. ), The same vehicle integrated roof rail was formed under the same conditions as in Example 1 except that the volume corresponding to 30% of the volume of the cavity portion for forming the rail portion was expanded. The hollow state of the rail portion of the molded integral roof rail for a vehicle is 30% of the volume of the rail portion.
%, The appearance was good, and the strength and weight satisfied the object of the present invention.

[0029]

According to the present invention, the integrated roof rail for a vehicle made of a thermoplastic resin in which the rail portion and the leg portion are integrated is compared with a conventional roof rail in which the leg portion and the rail portion are individually formed of metal or resin. It is easy to manufacture and lightweight, and meets the social demands for energy saving and improved fuel efficiency. Further, when the rail portion is hollowed, weight reduction, dimensional stability, improvement of appearance, and the like can be further promoted, and a more excellent vehicle roof rail can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view showing an example of an integrated roof rail for a vehicle according to the present invention.

FIG. 2 is an explanatory view schematically showing one example of a method for manufacturing an integrated roof rail for a vehicle according to the present invention.

FIG. 3 is an explanatory view schematically showing another example of the method for manufacturing the integrated roof rail for a vehicle according to the present invention.

FIG. 4 is a diagram showing an example of a conventional roof rail.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Leg part 2 Rail part 3 Hollow part 4 Subcavity 5 Cavity 6 Passage 7 Movable part

Claims (5)

[Claims] 1. An integrated roof rail for a vehicle, which is an injection-molded product of a thermoplastic synthetic resin in which a leg portion and a rail portion for attachment to a roof of a vehicle are integrated. 2. The integrated roof rail for vehicles according to claim 1, wherein the thermoplastic resin is a polyamide resin composed of hexamethylene diadipamide units and hexamethylene isophthalamide units. 3. The integrated roof rail for a vehicle according to claim 1, wherein 15 to 75% of the total volume of the rail portion is made hollow by hollow injection molding. 4. A subcavity having a volume corresponding to 15 to 75% of the total volume of the rail portion is connected to a cavity for molding the leg portion and the rail portion via a passage, and a mold is provided in the cavity. A method of molding an integrated roof rail for a vehicle, wherein the injection molding is performed by hollow injection molding in which a pressurized gas is press-fitted into a cavity after the thermoplastic resin is injected and filled, and the thermoplastic resin in the cavity is extruded into a sub-cavity. . 5. A mold for increasing a volume of a cavity portion for molding a rail portion of a cavity for molding a leg portion and a rail portion by a volume corresponding to 15 to 75% of a total volume of the rail portion. A molding method for a vehicle integrated roof rail, comprising: injecting a thermoplastic resin into a cavity before expansion, filling the cavity with a pressurized gas, and expanding the cavity volume by hollow injection molding.