JP3036341B2 - Manufacturing method of road wheel disc - 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 a disk for a road wheel, in which a material formed by casting is formed into a final shape by forging.

[0002]

2. Description of the Related Art A method of manufacturing a road wheel disk of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 3-14031.

In the manufacturing method disclosed in the above publication, first, a disk part material is manufactured by casting, and at this time, the disk part material is formed into a shape approximate to a final product (disk member). Thereafter, the disk member is formed by forging to obtain a disk member for a vehicle wheel.

[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 forged. Roughness can be reduced to only about Ra 4 μm, and improvement in improving design properties has been demanded.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a road wheel disc obtained by casting and forging processes, which can achieve an improved design and the like. It is an object of the present invention to provide a method of manufacturing a disc for use.

[0006]

According to a first aspect of the present invention, there is provided a method of manufacturing a disk for a road wheel , comprising the steps of: forming a disk material by casting ;
Process of forging a material with a forging die and forming it into a disk shape
And the same as the forging die used in the previous process
Forging at least once in a mold, complete finish forming and table
Claim 2 is a configuration comprising a step of pressing the surface.
Te, by forging, a step of molding a disc material, wherein
Heat the disc material above the recrystallization temperature and use a forging die
Forging and forming into a disk shape;
At least 1 in the same mold as the forging mold used in the previous process
Round forging, complete finish forming and surface pressing
The extent, a configuration which includes, as claimed in claim 3, by forging,
Forming the disc material and re-using the disc material.
After heating above the crystallization temperature, forging with a forging die
Forming the disk material into the shape,
Heating at the same temperature as the heating temperature of
Forging at least once with the same die as the forged die
And a step of pressurizing the surface and pressurizing the surface . The above-mentioned configuration is used as a means for solving the problem.

[0007]

According to the method for manufacturing a disk for a road wheel according to the first aspect 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 by the flow of the material, and nests inside the material generated during casting appear on this surface. Therefore, by forging at least once a disk material in the forging die of the same type used in the previous step <br/>, the surface pressurizes the molding finishing the entire disk material and <br/> also Crush the nest. As a result, a disk whose surface is finished without nests can be obtained.

In the method for manufacturing a disk for a road wheel according to claims 2 and 3 of the present invention, the first forging is performed.
Before forging or before each forging, the disk material is heated to a temperature higher than the recrystallization temperature to reduce the deformation resistance during forging. The nest at the rounded corner (R portion) where forging defects are likely to occur due to the nest that has appeared is finished in a sufficiently crushed state.

[0009]

FIG. 1A is a view for explaining a disc material after casting as an embodiment of the present invention. Disc material M
Is made of, for example, an aluminum alloy (6061),
In the center, the back and has a hub mounting portion H of the slightly concaved (lower side in FIG. 1), the outer periphery of the hub mounting portion H, has a spoke portion S of a convex portion A and a concave portion B, further, the spokes The outer periphery of the portion S has an annular inner rim joint J protruding to the rear side, and the outer periphery of the inner rim joint J has a rim m that becomes an outer rim R after forging, so that the overall final shape Is formed in a shape corresponding to the disk D. In addition, a hole C for obtaining a material flow at the time of forging is provided at the center of the hub mounting portion H.

In the method of 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 an aluminum alloy (6061) is about 200 ° C. In this embodiment, the deformation resistance is reduced by heating to twice or more the temperature.) Then, as shown in FIG. 1B, the forging provided with the upper mold 1 and the lower mold 2 is performed. The first forging is performed on the disk material M 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, the material of the disk material M naturally flows, and the material inside the disk material M Flow forms a new surface on which the nests inside the material generated during casting appear.

Therefore, in this manufacturing method, the disk material M is subjected to a second forging with the same forging die 3, or the disk material M is heated again to about 450 ° C. Perform the second forging. As a result, the entire disc material M is finish-molded, and the nest is crushed by pressurization of the surface. As shown in FIG. 1C, the disc is finished in a good state without nests. Shaped as D. Note that a surface roughness Ra of 2 μm could be obtained by the manufacturing method.

By the way, nests appearing on the surface during the first forging may cause forging defects such as insufficient thickness of the meat, particularly at the rounded portions (R portions) provided at the corners of the irregular 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, to increase the degree of working, and to finish the nest of the rounded corner portion sufficiently. Further, the temperature drop of the disk material M immediately after the first forging is about 30 ° C., and a good surface can be obtained even if the forging is performed twice continuously after heating, but the second forging is performed. If heating is performed again before then, better molding is achieved.

Incidentally, it is naturally possible to perform forging two or more times by using the same forging die 3, and it is possible to perform better forming than in the case of two forgings. However, the change in the degree of processing and the improvement in surface quality are extremely small even if the above process is performed, and the number of processes may be unnecessarily increased. Therefore, forging three times is sufficient.

Further, the disk D after forging is subjected to processing such as cutting of the back surface later, and the concave portion B becomes an air hole by removing the bottom. Further, the road wheel provided with the disk D of the present embodiment is a so-called two-piece type including a disk D integrally having an outer rim R and an inner rim (not shown) manufactured separately.
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 disk for a road wheel according to the first aspect of the present invention, a disk for a road wheel obtained by a casting and forging process is subjected to two or more forgings. By performing finish molding and crushing the nest on the surface, it is possible to increase the degree of processing and not to leave nests on the surface.
A good finished disk can be obtained, and the design (black scale surface properties) can be improved. In addition, since the same die is used for forging, the cost of the die is reduced and the cost is reduced accordingly. It can contribute to such things.

Further, according to the method for manufacturing a road wheel disc according to claims 2 and 3 of the present invention,
In addition to obtaining the same effects as in Example 1 , heating at a temperature higher than the recrystallization temperature reduces the deformation resistance at the time of forging, so that the workability and design can be further improved, and especially, the forging defect is improved. A corner portion where the occurrence of cracks can easily be formed very well.

[Brief description of the drawings]

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

[Explanation of symbols]

 D disk M disk material 3 Forging die

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-127040 (JP, A) JP-A-2-179336 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21J 1/00-13/14 B21K 1/32 B21D 53/30

Claims (3)

(57) [Claims] 1. A process for forming a disk material by casting.
And forging the disk material with a forging die to form a disk shape.
Forming step, the same as the forging die used in the previous step of the disk material
Forging at least once, complete finishing and surface
A step of pressurization, the manufacturing method of the disc for road wheel, characterized in that it includes. 2. A process for forming a disk material by forging.
And forging after heating the disc material above the recrystallization temperature
Forging with a die, forming into a disk shape, and using the same die as the forging die used in the previous process for the disk material
Forging at least once, complete finishing and surface
A step of pressurization, the manufacturing method of the disc for road wheel, characterized in that it includes. 3. A process for forming a disk material by forging.
And forging after heating the disc material above the recrystallization temperature
Forging in a mold and forming into a disk shape; and forming the disk material at the same temperature as the first heating temperature.
After heating, use the same mold as the forging mold used in the previous process.
Forging at least once, finishing and pressing the entire surface
Step a method for manufacturing a disc for road wheel, characterized in that it comprises for a.