JPH0698417B2 - Method for producing cast light alloy wheel - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a cast light alloy wheel for a motorcycle.

[Prior art]

Conventionally, the rim and the hub were connected by a disc-shaped disc portion,
In a so-called disc wheel, the rim, the hub and the disc portion are integrally cast-molded with a light alloy material, and thereafter,
It is known that the whole wheel is cut.

By the way, in this type of disc wheel, a plurality of openings are often formed in the disc part in consideration of not only the appearance but also the influence of cross wind during traveling. It is formed by integrally casting the opening.

[Problems to be solved by the invention]

However, when forming the opening by casting,
Since the flow path of the molten metal in the casting die becomes complicated, casting defects may occur unless the die is designed with due consideration of the molten metal surroundings.

In addition, when the opening is cast, the inner surface of the opening needs to be coated in order to make the casting surface inconspicuous, which increases the man-hours and costs.

In addition, when it was necessary to change the shape and position of the opening due to the change of the wheel design, it was necessary to remake the entire expensive casting mold, which was very troublesome. [Means for Solving the Problems] Therefore, in the method of the present invention, when forming a plurality of openings in the disc-shaped disk portion, the openings were punched by pressing after the disk portion was cast. It is characterized by

[Action]

According to such a method of the present invention, since there is no opening in the disc portion at the stage of casting and the disc portion has a continuous disc-like shape, the melt flow is good and the casting It is possible to manufacture a good quality wheel with few defects.

Moreover, unlike the case of conventional casting, the inner peripheral surface of the opening does not have a rough casting surface, so a beautiful appearance can be obtained without special painting, which reduces the number of work steps. And cost can be reduced.

In addition, the shape and position of the opening can be changed simply by changing the punching die of the press. Therefore, changes in the wheel design can be easily dealt with, and expensive casting dies can be repeated as they are. Since it can be used, it is also advantageous in terms of cost.

Example of Invention

An embodiment of the method of the present invention will be described below with reference to the drawings applied to a wheel for a motorcycle.

The wheel made of an aluminum alloy indicated by reference numeral 1 in the drawing has a rim 2,
A hub 3 and a disc-shaped disc portion 4 connecting the rim 2 and the hub 3 are integrally cast, and a plurality of openings 5 ... Are formed in the disc portion 4 at intervals in the circumferential direction. Has been done.

Then, such a wheel 1 is manufactured by the procedure described below.

That is, by assembling a casting mold having a molding space corresponding to the rim 2, the hub 3 and the disc portion 4 and injecting molten metal into the mold, the rim 2, the hub 3 and the disc portion 4 are integrally cast. Mold.

After the molten metal is solidified, the mold is opened, the product is taken out, the rim 2 and the hub 3 are cut to finish to a regular size, and the surface 4a on one side of the disk portion 4 is also cut.

Next, the opening 5 is punched and formed in the disk portion 4 by press working. In this embodiment, the opening 5 is punched from the side 4a subjected to the cutting work, and this punching occurs. The flash 6, which is called a drain,
As shown in FIG. 3, the disk portion 4 is projected on the surface 4b on the opposite side which is not cut.

Thereafter, the surface 4b on the opposite side of the disk portion 4 on which the flash 6 is present is also cut to remove the flash 6 and at the same time finish the disk portion 4 to a regular size.

According to such an embodiment of the method of the present invention, at the stage of injecting the molten metal into the casting mold, the disc portion 4 has no openings 5 ... Since it has a disc shape, the flow path of the molten metal in the disk portion 4 does not become complicated. For this reason, the bathing area becomes good, and it is possible to manufacture the wheel 1 with good quality and less complicated defects.

In addition, since the inner peripheral surface of the opening 5 ... does not have a rough casting surface unlike the conventional casting, a beautiful appearance can be obtained without special painting, and therefore, the number of working steps can be reduced. Therefore, the cost can be reduced.

Further, by changing the punching die of the press, the shape and position of the openings 5 can be arbitrarily changed as shown by the imaginary line in FIG. 1, so that the wheel design can be easily changed. In addition to this, an expensive casting mold can be repeatedly used as it is, which is advantageous in terms of cost.

Further, in this embodiment, after the surface 4a on one side of the disk portion 4 is cut, the opening 5 is formed from the side of the processed surface 4a.
.. is punched and then the surface 4b on the opposite side of the disk portion 4 is cut, so that the flash 6 generated during the punching can be removed simultaneously with the cutting processing of the disk portion 4. For this reason, a dedicated work process for removing the flash is unnecessary, which also contributes to cost reduction.

It should be noted that the present invention is not limited to the above-described embodiment, and, for example, after the surfaces 4a and 4b on both sides of the disk portion 4 are cut, the openings 5 are punched and formed, and the openings 5 are formed. The flash 6 may be incorporated as one of the appearance elements of the wheel 1 by positively leaving the flash 6 referred to as a weep in 5 ...

In this case, since the direction of the flash 6 is aligned with one surface side of the wheel 1, if the brake disk is attached to the end surface of the hub 3 which is directed to the side opposite to the flash 6,
The brake disc and the flash 6 are weight-balanced, and the weight balance of the entire wheel 1 can be maintained well.

Further, when the openings 5 are punched and formed, the burrs 6 are alternately arranged on both sides of the disk portion 4 if the punching directions are alternately reversed along the arrangement direction of the openings 5. Therefore, the left and right of the disk portion 4 can be balanced, which is convenient in terms of appearance.

〔The invention's effect〕

According to the present invention described in detail above, since the casting can be performed in the state where the disk portion has no holes, a wheel with good quality and less casting defects and good quality can be obtained. In addition, since the inner peripheral surface of the opening does not have a rough casting surface, a beautiful appearance can be obtained without special coating, and therefore, the number of working steps can be reduced and the cost can be reduced.

In addition, the shape and position of the opening can be changed just by changing the punching die of the press, which makes it possible to easily deal with changes in the wheel design.
An expensive casting mold can be repeatedly used, which is advantageous in terms of cost.

[Brief description of drawings]

The drawings show one embodiment of the method of the present invention. Fig. 1 is a side view of a wheel, Fig. 2 is a sectional view, and Fig. 3 is a sectional view around an opening. 1 ... wheel, 2 ... rim, 3 ... hub, 4 ... disk part, 5 ... opening part.

Claims (4)

[Claims] 1. A method of manufacturing a wheel in which a plurality of openings are formed in a disc-shaped disc portion connecting a rim and a hub, wherein the rim, the hub and the disc portion are integrally cast from a light alloy material. After that, a method for manufacturing a cast light alloy wheel is characterized in that a plurality of openings are punched by press working in the disk portion. 2. A surface of one side of the disk portion is subjected to a cutting process, the opening is punched from the surface side subjected to the cutting process, and then a surface of the opposite side of the disk portion is cut. A method for producing a cast light alloy wheel according to claim (1), characterized by being processed. 3. A cast light alloy wheel as set forth in claim 1, wherein the openings are punched after cutting both sides of the disk portion. Method. 4. When punching the openings after cutting both sides of the disk portion, the punching directions of the openings are alternately reversed along the arrangement direction of the openings. The method for producing a cast light alloy wheel according to claim (3), characterized in that.