JP3233284B2 - Manufacturing method of aluminum alloy vehicle wheel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an aluminum alloy vehicle wheel used for an automobile or the like.

[0002]

[Prior art]

2. Description of the Related Art Conventionally, as a wheel for a vehicle such as an automobile, a wheel made of an aluminum alloy or the like (hereinafter, referred to as an aluminum wheel) has been used in order to reduce the kinetic inertia.

By the way, since this type of vehicle wheel is also a component of the appearance of a vehicle, it is necessary to be able to freely color various colors in order to improve the appearance.

Further, the vehicle wheel is located near the road surface and is exposed to muddy water, salt water, or the like accompanying the traveling of the vehicle. However, the dirt is easily removed and the vehicle wheel has good corrosion resistance. Is important as the appearance performance of

[0005] Some conventional aluminum wheels have an alumite film formed on the surface to improve the corrosion resistance and decorativeness of the surface.

[0006]

[Problems to be solved by the invention]

However, in an aluminum wheel having a conventional alumite coating, the alumite coating may be formed as a colored transparent body depending on the aluminum material used as a base material, giving a transparent feeling without turbidity and various colors. Is limited, and may not be able to satisfy the requirements for appearance.

Further, since various irregularities are formed on the surface of the vehicle wheel, the appearance of dirt such as mud adhering to the surface of the alumite coating on the outside of the vehicle can be easily improved. It is a good thing.

The present invention has been made in view of the above circumstances, and further enhances the appearance of an aluminum wheel having an alumite film on the surface by increasing the degree of transparency and freedom of coloring and improving dirt removal. It is intended to improve.

[0009]

[Means for Solving the Problems]

In order to achieve this object, a first aspect of the present invention is a method for manufacturing an aluminum alloy vehicle wheel in which an alumite coating is formed on the surface of an aluminum wheel having a rim portion and a disk portion, wherein the aluminum wheel is made of a casting. In some cases, the design surface of the disk portion on the outer side of the vehicle body is surface-finished by polishing to a surface roughness of Rmax3 μm or less, and the surface-finished design surface is harder than Vickers hardness Hv250 and has a thickness of 20 μm. After forming the alumite coating with a weak surface roughness Rmax5 μm,
The alumite film is polished to a surface roughness Rmax of 5 μm or less.

[0010]

[Operation]

Cast aluminum wheels have a much rougher surface property than aluminum wheels made of wrought materials or the like, so that even if an alumite film is formed on the surface as it is, only a rough alumite film can be obtained. Therefore, it is necessary to make the alumite coating extremely thin in order to obtain transparency, but the alumite coating has to be made thicker even at the expense of transparency because the alumite coating wears off a lot with aluminum wheels. . However, in the present invention, the aluminum wheel design surface is polished to a surface roughness Rmax3μ.
By performing the surface finishing to a thickness of not more than m, an alumite coating can be formed uniformly. In addition, the design surface of the aluminum wheel is polished to a surface roughness of Rmax3μm or less, and the alumite film is coated
By polishing to an Rmax of 5 μm or less, irregular reflection on the design surface and irregular reflection on the alumite coating surface can be suppressed at the same time. Thus, it became possible to form an alumite film having a thickness of less than 20 μm without losing the transparency.

As described above, since it is possible to form an alumite film having a thickness of less than 20 μm without losing transparency, it is possible to achieve a balance between the two functions of securing transparency and extending the life. By overcoming the weak points of cast aluminum wheels with a rough surface, a smooth design surface almost equivalent to that of wrought aluminum wheels can be obtained. Moreover, by making the surface of the alumite film smooth (preferably a mirror surface), mud and the like adhering to the alumite film are easily removed,
Since the alumite film is hardly stained, the aluminum wheel can maintain a good appearance with little stain for a long time.

Further, the hardness of the alumite film is set to Vickers hardness Hv250.
Since the height is higher, the life of the alumite coating can be further extended.

[0013]

【Example】

Hereinafter, an embodiment shown in the drawings will be described. In the following, for convenience of description, a method of manufacturing an aluminum wheel will be described first with reference to FIGS. 3 and 4 in order, and thereafter, an aluminum wheel as a product will be described. Will be described.

In this embodiment, an aluminum alloy (for example,
A wheel material cast into a predetermined shape using AC4C) is prepared in advance.

Then, the wheel material is formed into a wheel shape by predetermined machining, and thereafter, a surface treatment such as an alumite treatment is performed.

In this machining, mainly, a groove on the outer periphery of a rim of a wheel to which a tire is mounted, and a side surface (hereinafter referred to as a design surface) which is an outer surface of a vehicle body when the wheel is mounted on an automobile. Then, cutting and grinding are performed.

In the case of this embodiment, buffing is particularly performed on the design surface, and a good surface finish is performed so that the surface roughness becomes Rmax 3 μm or less.

The wheel material thus machined and finished is thereafter subjected to surface treatment on the design surface.

This surface treatment is performed in each step shown in FIG.

That is, in this surface treatment, first, the surface of the design surface of the wheel material on which the alumite film is formed is immersed in a commercially available aluminum cleaner to perform degreasing.
Wash with water.

After such pretreatment, the wheel material is subjected to the following anodizing treatment (hereinafter, referred to as alumite treatment).

This alumite treatment is carried out using a known alumite equipment. For example, an aqueous solution of 180 g / liter of sulfuric acid is used as an electrolytic solution, the temperature is kept at + 5 ° C., the current density is 3 A / dm ² ,
The process is carried out until the thickness of the film becomes less than 20 μm.

The alumite coating is a so-called hard alumite coating, and has a hardness higher than Vickers hardness Hv250.

After the alumite treatment, the wheel material having the alumite film (hereinafter simply referred to as a film) formed on the surface of the design surface is washed with water.

The surface roughness of the alumite film formed by the alumite treatment is affected by the aluminum material and the conditions of the alumite treatment, but is generally Rmax5 μm or less.

When the surface roughness of the alumite film exceeds this, the surface of the alumite film is polished by buffing or the like as described later, and the surface roughness is set to Rmax5 μm. The following is assumed.

Since the thickness of the alumite film thus obtained is slightly less than 20 μm as described above, even if the alumite film is a colored transparent body, it remains as a colorless transparent body as it is. When the alumite film is not colored, it can be visually recognized and can give a transparent feeling without turbidity to the design surface. After washing with water, the sealing process described below is performed, and the surface is polished if necessary. The product is obtained.

As described above, since the surface roughness of the base material is made high precision, it becomes easy to uniformly form an alumite film formed on the surface of the aluminum wheel in the alumite treatment.

In addition, since the surface roughness of the alumite film formed on the surface of the high-precision base material does not deteriorate so much and is formed with high precision, the surface formed by the alumite treatment can easily remove dirt, Alternatively, the finishing process for improving the stain removal can be performed with very few simple processes.

The coloring of the alumite film is performed, for example, as follows.

That is, after washing with water after the alumite treatment, 60 to 70
Dry the wheel material with hot air at ℃.

On the surface of this alumite film, several hundreds of pores having openings of 100 to 300 angstroms in diameter per 1 cm ² are formed, and the alumite film having such a surface is subjected to the following coloring treatment. Is performed.

As the coloring treatment, for example, a coloring material obtained by dissolving a black oil-based dye 4 (trade name: Oil Color) manufactured by Orient Co., Ltd. in a volatile solvent such as acetone, cyclohexanone or toluene is filtered, and the above-described alumite coating is applied. The upper portion is applied by brushing or dipping, and after wiping off excess portions, hot air drying is performed.

As described above, the oily dye is dissolved in the solvent in the coloring treatment and used, because the pore diameter of the pore formed in the alumite coating tends to decrease as the hardness increases.

That is, the solvent of the oily dye is compared with the water of the aqueous dye,
Since the surface tension is small, it can be expected that the pores to be filled with the dye are expected to have an advantageous effect in reliably filling the inside of the dye from the small openings of the pores. This is because the dye can be surely contained in many of them.

After this coloring treatment, a sealing treatment of the alumite film is performed.

The sealing treatment in this embodiment is performed by immersing a nickel acetate aqueous solution having a concentration of 7 g / liter at 80 to 95 ° C. for 20 minutes.

[0038] Note that it is also possible to immerse the mixture in distilled water at 90 to 100 ° C for 20 minutes, or to perform pore sealing with steam.

When the surface treatment is completed after the sealing treatment is performed and the surface roughness of the alumite film is not more than Rmax5 μm, a predetermined finishing of a portion other than the design surface on which the alumite film is formed is performed. The result is an aluminum wheel as a product.

On the other hand, the surface roughness of this alumite coating is Rmax5 μm
In the case of exceeding, the surface of the alumite film is polished as mentioned above.

The polishing step in this embodiment is a buffing process, which is performed using a compound containing fine abrasive grains such as alumina, and the surface of the alumite film formed on the design surface has a surface roughness. As described above, it is finished to have Rmax of 5 μm or less.

Then, similar to the above case where the polishing is not performed,
The predetermined finishing of other parts is performed to obtain an aluminum wheel as a product.

Note that the polishing step is not limited to buffing,
Other finishing methods such as super finishing and lap finishing may be used.

As described above, even when the surface of the alumite film is polished, as described above, the design surface of the wheel material on which the alumite film is formed is finished with high precision beforehand. As a result, the alumite coating formed on this design surface is of high precision, and even if its surface roughness exceeds Rmax 5 μm, it will be so large.

For this reason, the surface roughness can be easily and accurately increased in a short time by polishing using free abrasive grains having low processing efficiency such as buffing.

In addition, since the surface of this alumite film is finished by such a processing method having a low processing efficiency, even if the thickness of the alumite film formed on the design surface is formed to be less than 20 μm, it is difficult to process in the manufacturing process. And there is no need to form an unnecessarily thick alumite film at the expense of transparency as in the prior art.

Accordingly, it is possible to reduce the processing time and the consumption of electric power and the like associated with the formation of the alumite film, and even if the alumite film formed as described above is a colored transparent body, To ensure transparency without turbidity,
Free coloring is possible.

The aluminum wheel 1 manufactured as described above is
It is formed as shown in the figure.

That is, the aluminum wheel 1 has the rim 2 and the disk 3.

The aluminum wheel 1 is provided with a locking bolt 6 protruding from a brake drum 5 formed at the tip of an axle 4 of the automobile.
Is inserted into a steel sleeve 7 cast into the disk portion 3 and mounted on the brake drum 5 with a nut 8. A tire (not shown) is mounted on the outer periphery of the rim portion 2 for use.

Therefore, the side surface of the disk portion 3 opposite to the axle 4 and the brake drum 5 is a surface having a side surface appearance of the automobile, and is a design surface 11 in which the appearance is emphasized.

Incidentally, OO in FIG. 1 is a rotation center axis of the aluminum wheel 1.

The alumite film 12 formed as described above exists over the entire outer surface of the disk portion 3 forming the design surface 11 of the aluminum wheel 1.
The details are as shown in FIG. 2, for example, in which part A in FIG. 1 is enlarged.

That is, in FIG. 2, reference numeral 13 denotes a base material made of an aluminum casting, and the alumite film 12 is formed on the surface thereof.

A large number of pores 14 formed on the surface of the alumite film 12 are filled with a dye 15 and colored,
The opening on the surface of 14 is closed by a sealing treatment.

The thickness t of the alumite coating 12 is 20 μm as described above.
m, which is thinner than before.

Therefore, even if the alumite film 12 is formed as a colored transparent body, if the pores 14 are not filled with a dye, the pores 14 are substantially visually recognized as a colorless transparent body, and can give a sense of transparency.

In addition, when the dye 15 is filled in the pores 14 to color the alumite coating 12 as in this embodiment, and particularly when the color of the dye 15 is a light color, Due to the alumite film 12, the color becomes turbid, but as described above, since the alumite film 12 is formed extremely thinly, the dye 15 does not become turbid due to the color of the alumite film 12, so that it can be freely formed. Can be colored.

Further, as described above, the surface of the alumite coating 12
Since the surface roughness of 12a is not more than Rmax5 μm, even if there is adhesion to mud or the like on the design surface 11 due to the running of the vehicle, it is easy to peel off, and a good appearance can be maintained for a long time.

[0060]

【The invention's effect】

As described above, the invention of claim 1 relates to a method of manufacturing an aluminum alloy vehicle wheel for forming an alumite film on the surface of an aluminum wheel having a rim portion and a disk portion, wherein the aluminum wheel is made of a casting. In addition, the design surface of the disk portion on the outer side of the vehicle body is subjected to surface finishing by polishing to a surface roughness Rmax3 μm or less,
On the surface having been subjected to the surface finishing, the Vickers hardness is higher than Hv250, the thickness is slightly less than 20 μm, and the surface roughness is Rmax5.
After forming the alumite film having a thickness of about μm, the alumite film is polished to a surface roughness Rmax of 5 μm or less, so that the following effects are obtained.

A cast aluminum wheel has a significantly rougher surface property than an aluminum wheel made of wrought material or the like, so that even if an alumite film is formed on the surface as it is, only a rough alumite film can be obtained. Therefore, it is necessary to make the alumite coating extremely thin in order to obtain transparency, but the alumite coating has to be made thicker even at the expense of transparency because the alumite coating wears off a lot with aluminum wheels. . However, in the present invention, the aluminum wheel design surface is polished to a surface roughness Rmax3μ.
By performing the surface finishing to a thickness of not more than m, an alumite coating can be formed uniformly. In addition, the design surface of the aluminum wheel is polished to a surface roughness of Rmax3μm or less, and the alumite film is coated
By polishing to an Rmax of 5 μm or less, irregular reflection on the design surface and irregular reflection on the alumite coating surface can be suppressed at the same time. Thus, it became possible to form an alumite film having a thickness of less than 20 μm without losing the transparency.

As described above, it is possible to form an alumite film having a thickness of up to less than 20 μm without losing the transparency, and it is possible to achieve the balance between functions of securing transparency and extending the life. By overcoming the weak points of cast aluminum wheels with a rough surface, a smooth design surface almost equivalent to that of aluminum wheels made of advanced materials can be obtained. Moreover, by making the surface of the alumite film smooth (good mirror surface), the mud and the like adhering to the alumite film fall off well,
Since the alumite film is hardly stained, the aluminum wheel can maintain a good appearance with little stain for a long time.

Further, the hardness of the alumite film is determined by Vickers hardness Hv250.
Since the height is higher, the life of the alumite coating can be further extended.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory sectional view of an aluminum wheel according to an embodiment of the present application.

FIG. 2 is an enlarged sectional view of a portion A in FIG.

FIG. 3 is a manufacturing process diagram of an aluminum wheel.

FIG. 4 is a process chart of a surface treatment.

[Explanation of symbols]

t; Alumite coating thickness 1; Aluminum wheel (aluminum alloy vehicle wheel) 12; Alumite coating 12a; (Alumite coating) surface 13; Aluminum base material (base material)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-190097 (JP, A) JP-A-1-186401 (JP, A) JP-A-61-157694 (JP, A) JP-A-1 119638 (JP, A) JP-A-61-250193 (JP, A) JP-A-64-65294 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60B 3/02

Claims (1)

(57) [Claims] 1. A method for manufacturing an aluminum alloy vehicle wheel, wherein an alumite coating is formed on the surface of an aluminum wheel having a rim portion and a disk portion, the method comprising: The finished design surface is surface-finished by polishing to a surface roughness Rmax3 μm or less, and the surface-finished design surface is harder than Vickers hardness Hv250, the thickness is slightly less than 20 μm, and the surface roughness Rmax5 μm.
A method for manufacturing a vehicle wheel made of an aluminum alloy, comprising: forming the above-described alumite film and polishing the alumite film to a surface roughness Rmax of 5 μm or less.