JPH07178500A - Manufacture of disk for road wheel - Google Patents

Abstract

PURPOSE:To improve the design by forging a disk stock, and manufacturing the disk stock using the same die more than the prescribed time in a disk for a road wheel to be obtained in the processes of forging and casting. CONSTITUTION:When the disc stock M of aluminum alloy, for example, is placed in a furnace and heated at about 450 deg.c, the first forging of the disk stock is executed by a forging die 3 provided with an upper die 1 and a lower die 2. The disc stock M is formed to the shape of the disk D of the final shape, but the inner material flows on the surface side to form the new surface, and the porosity in the stock which is generated in the casting appears on this surface. Thus, the second forging is executed by the same forging die 3 for the disk stock M. The finish forming of the whole disk stock is executed, and at the same time, the porosity is crushed by the pressure applied on the surface, and the disk D which is surface finished to the excellent condition without porosity is formed.

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 a road wheel disc, in which a material formed by casting is forged into a final shape.

[0002]

2. Description of the Related Art As a method of manufacturing a disk for a road wheel of this type, there is one disclosed in, for example, Japanese Patent Laid-Open No. 1432031/1992.

In the manufacturing method disclosed in the above publication, first, a disk portion material is manufactured by casting, and at this time, the disk portion material is formed into a shape similar to the final product (disk member). After that, the disc member of the vehicle wheel is obtained by forging the disc portion material.

[0004]

However, in the method of forging a cast material as in the above-mentioned conventional manufacturing method, for example, when a cast material having a surface roughness Ra of 12 μm is forged, the surface of the molded product is The roughness can only be about Ra 4 μm, and there has been a demand for improvement in improving the design.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and in a road wheel disk obtained by the steps of casting and forging, it is possible to improve the design of the road wheel. It is an object of the present invention to provide a method for manufacturing a disc for use in a computer.

[0006]

According to a first aspect of the present invention, there is provided a method of manufacturing a disc for a road wheel according to claim 1, wherein the disc material is formed by casting, and then the disc material is heated, and then the same die is used two or more times. A disk material is formed by forging, and the disk material is molded by casting according to claim 2, and then the disk material is heated to a recrystallization temperature or higher, and then forged with the same die twice or more to form the disk. It is configured to be molded, and also
In Claim 3, a disk material is formed by casting,
After this, the disc material is heated at a temperature higher than the recrystallization temperature for the first time and then forged for the first time. Then, the disc material is heated again at the same temperature as the first heating temperature, and then the same die is used. The disk is formed by performing the forging for the second time, and the above-mentioned structure is used as a means for solving the problem.

[0007]

In the method for manufacturing a road wheel disc according to claim 1 of the present invention, in the first forging,
The cast disc material is formed into a disc shape.
At this time, a new surface is formed on the disk material due to the flow of the material, and on this surface, cavities inside the material generated during casting appear. Therefore, by performing forging two or more times with the same die, the entire surface of the disk material is finish-formed and the surface thereof is pressed to crush the cavities. This allows
A disc that is surface-finished in the absence of cavities will be obtained.

In the method for manufacturing a road wheel disk according to claims 2 and 3 of the present invention, the deformation resistance during forging is reduced by heating the disk material to a temperature higher than the recrystallization temperature, and the method according to claim 1 is manufactured. Similar to the method, a disk is formed, and in particular, the cavities of the rounded corners (R portion) where a forging defect is likely to occur due to the cavities appearing on the surface are sufficiently crushed.

[0009]

EXAMPLE FIG. 1 (a) is a view for explaining a disk material after casting as an example of the present invention. Disc material M
Is made of, for example, an aluminum alloy (6061),
At the center, a hub mounting portion H that is recessed on the back side (lower side in FIG. 1) is provided, and at the outer circumference of the hub mounting portion H, there is a spoke portion S composed of a recess A and a protrusion B. The outer periphery of S has an annular inner rim joint J that projects to the back side, and the outer periphery of the inner rim joint J has a rim m that becomes the outer rim R after forging, so that the final shape as a whole is obtained. It is formed into a shape corresponding to a certain disk D. In addition, a hole C is provided in the center of the hub mounting portion H for obtaining the flow of material during forging.

In the method for manufacturing a disk for a road wheel according to the present invention, the disk material M is placed in a furnace at about 450 ° C. (the recrystallization temperature in the case of aluminum alloy (6061) is about 200 ° C., In this embodiment, the deformation resistance is lowered by heating at a temperature twice or more that of the above), and then forged with an upper die 1 and a lower die 2 as shown in FIG. 1 (b). The disk material M is subjected to the first forging by the mold 3.

As a result, the disk material M is formed into the shape of the disk D which is the final shape. At this time, a material flow naturally occurs in the disk material M, and the internal material is on the surface side. A new surface is formed by flowing to the inside, and the cavities inside the material generated during casting appear on this surface.

Therefore, in the manufacturing method, the disk material M is forged a second time by the same forging die 3, or the disk material M is heated again to about 450 ° C. and then the same forging die 3 is used for 2 times. Perform the second forging. As a result, the entire disc material M is finish-molded, and the cavities are crushed by the pressure applied to the surface. As shown in FIG. 1C, the disc material M is surface-finished in a good state without cavities. Molded as D. A surface roughness Ra of 2 μm could be obtained by the manufacturing method.

By the way, the cavities appearing on the surface during the first forging cause a forging defect such as insufficient meat tension, particularly in the rounded portion (R portion) provided at the corner of the uneven shape of the disk material M. There is.

On the other hand, in the manufacturing method, the disk material M is heated to reduce the deformation resistance at the time of forging, the workability is increased, and the cavities of the rounded corners are also sufficiently crushed. Further, the temperature decrease of the disk material M immediately after the first forging is about 30 ° C., and a good surface can be obtained even when the forging is performed twice continuously after heating, but the second forging is performed. Better molding can be achieved by heating again before.

Of course, it is possible to perform the forging more than twice by using the same forging die 3, and it is possible to perform better forming than the case of the forging of two times, but the forging of the fourth time is performed. Even if it is carried out, there is very little change in the workability and the improvement of the surface quality, and the number of steps may be unnecessarily increased.

Further, the disk D after forging is later subjected to processing such as cutting on the back surface, and the concave portion A becomes an air hole by removing the bottom portion thereof. Further, the road wheel including the disc D of the present embodiment is called a two-piece type including a disc D integrally having an outer rim R and a separately manufactured inner rim (not shown),
This is completed by joining the inner rim to the inner rim joint J of the disc D by welding.

[0017]

As described above, according to the method for manufacturing a road wheel disk according to the first aspect of the present invention, the road wheel disk obtained by the steps of casting and forging is forged twice or more. By finishing molding and crushing the cavities on the surface, it is possible to improve the workability and improve the designability (black skin surface property). In addition, since the same die is used for forging, It can contribute to the saving of mold costs and the associated cost reduction.

Further, according to the method for manufacturing a road wheel disk according to claims 2 and 3 of the present invention, the deformation resistance at the time of forging is reduced by heating above the recrystallization temperature, so that the workability and the design are improved. It is possible to further improve the property, and it is possible to extremely excellently shape the corner portion where a forging defect is likely to occur.

[Brief description of drawings]

FIG. 1 is a view for explaining an embodiment of a method for manufacturing a road wheel disc according to the present invention, which is a disc material (a) formed by casting, a forging die and a disc material (b) in the first forging. ), And a forging die and a disk (c) after the second forging, respectively.

[Explanation of symbols]

 D disc M disc material 3 Forging die

Claims (3)

[Claims] 1. A method of manufacturing a disk for a road wheel, comprising molding a disk material by casting, and then forging the disk material with the same die twice or more to mold the disk. 2. A disk for a road wheel, comprising molding a disk material by casting, heating the disk material to a recrystallization temperature or higher, and then forging the disk material twice or more with the same die to mold the disk. Manufacturing method. 3. A disk material is formed by casting, after which the disk material is first heated to a recrystallization temperature or higher and then forged for the first time, and then the disk material is again heated at the first heating temperature. A method for manufacturing a disk for a road wheel, which comprises heating the disk at the same temperature as above and then forging the disk for the second time using the same mold.