JPS6154504B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a method for manufacturing large forged wheels for trucks, buses, etc., and particularly tubeless wheels made of aluminum alloy.

This type of large wheel is generally made of steel, and as vehicles become lighter, lightweight wheels made of aluminum alloy are desired.

Based on this request, the present inventor has already established a manufacturing method for a tubed wheel and has also filed an application for the same. However, in the case of tubeless wheels, because the ring part has a complicated shape, it is not possible to obtain a product with a good yield using the above manufacturing method, and from a quality standpoint, some kind of manufacturing method is necessary. It is. Furthermore, if press forging is performed using a split die, the split die will become complicated, making it practically impossible.

The present invention has been proposed in view of the above circumstances, and an object of the present invention is to provide a manufacturing method that can efficiently manufacture a finishing material wheel for a large tubeless wheel.

In the manufacturing method of the present invention, a disc-shaped aluminum material is heated in the same way as in the case of a tubed wheel, and then in a first forging process, the ring part of the disc-shaped aluminum material is inclined at a required angle with respect to the rib part. A roughly dome-shaped rough material is formed, and then, in a second forging process, the rough material is bent and drawn to forge a roughly cup-shaped molded product in which the ring portion is approximately perpendicular to the rim portion. The ring part of the molded product is narrowed inward to match the minimum diameter part of the ring part of the final product, and the open side of the ring part is expanded outward to create a wavy ring that corresponds to the final product. The present invention is to obtain a finishing material wheel having a section.

The present invention will be described below based on an illustrated embodiment. The forging process shown in Figs. 1 and 2 is the same as that for tubed wheels, and the material used is a disc-shaped aluminum material 1 made by cutting a bar-shaped billet to a certain thickness, and this disc-shaped aluminum material 1 is heated. in the furnace
It is heated to 450-600°C and then sent to the first forging process shown in Figure 1. Here, the disc-shaped aluminum material 1 is rough-formed into a dome-shaped rough-ground product 2 in which the ring portion 2a is inclined at a predetermined angle α° with respect to the rim portion 2b. In this process, a concave portion 3a having an inverted trapezoidal shape is formed in the lower die 3, and a convex portion 4a corresponding to the concave portion 3a is formed in the upper die 4, whereby the disc-shaped aluminum material 1 is compressed. As a result, a rough ground product 2 with substantially uniform metal flow and appropriate volume distribution in each part can be obtained. The shapes of the upper mold 3 and the lower mold 4 are determined according to appropriate volume distribution, but the angle of inclination α of the ring portion 2a is preferably about 50° to 60°, and if it is larger than this, it will be uneven. Thickness is generated, and if it is less than this, the forging load will increase and the forging stroke in the next process will increase.

Next, this rough material 2 is sent to a second forging process as shown in FIG. 2, where each part of the rough material 2 is squeezed and bent so that the ring part 5a is approximately perpendicular to the rim part 5b to form a cup shape. A molded article 5 is obtained.
The shapes of the lower die 6 and the upper die 7 are determined in consideration of the machining allowance of the final product W. Furthermore, in this step, the ring portion 5a is drawn high and tends to stick to the mold surface, so the mold surface is chrome-plated and lubricant is also applied. In such a second forging process, the mortar-shaped rough material 2 that has been preformed in the first forging process is used, so the forging load is small and the forging stroke is shorter than when pressing plate materials. Furthermore, uneven thickness and eccentricity will not occur.

Through the above two steps, the molded product 5 is obtained without reheating, and at the end of these two steps, the temperature of the molded product 5 is 200°C to 300°C.
As shown in the figure, holes are punched at predetermined locations using a double action press.

Next, as shown in FIG. 4, the ring portion 5a of the molded product 5 is narrowed inward so that it matches the minimum diameter portion Wa of the ring portion of the final product W (see FIG. 7). In this drawing forging process, the ring portion 5a is drawn from the outer surface using the conical die 8, and the lower die 9 prevents excessive drawing. As a result, the opening side of the ring part of the final product W
Second molded product 1 corresponding to final product W except Wb
0 is obtained.

Subsequently, the ring portion 10a of this second molded product 10
A part of the ring part 10a is expanded outward using the upper and lower molds of the press (see Fig. 5), and then rolled with a Wagner mill, tire mill, etc. to expand the open side part 10b to form a shape corresponding to the final product W. A material wheel 11 for finishing processing is used. As shown in FIG. 6, the outer roll 12 and the inner roll 13 have shapes corresponding to the inner and outer surfaces of the ring portion of the processing material wheel 11, respectively. This rolling process not only forms the opening side portion 10b into a predetermined shape but also roll-forms the inner and outer surfaces, which has the advantage of improving the strength of the material. Note that this step is not limited to the combination of pressing and rolling, and may use only rolling or only pressing.

The finishing material wheel 11 formed through the above steps is finished into a final product W by cutting. Although the above description has been made regarding a large aluminum wheel, the manufacturing method of the present invention is not limited to this, and the manufacturing method of the present invention can be effectively applied to small-sized steel wheels as well.

As described above, according to the present invention, a tubeless wheel material for finishing can be obtained in just a few steps, resulting in good productivity and yield.
Furthermore, it has the advantage that a product with high strength can be obtained without any interruption in grain flow lines in each process.

[Brief explanation of the drawing]

1 to 6 are explanatory views showing the manufacturing process according to the present invention, FIG. 1 is a sectional view showing the first forging process, FIG. 2 is a sectional view showing the second forging process,
Fig. 3 is a sectional view showing the drilling process, Fig. 4 is a sectional view showing the drawing and forging process, Fig. 5 is a sectional view showing the opening side widening process by pressing, and Fig. 6 is a sectional view showing the rolling process. , FIG. 7 is an explanatory diagram showing cross-sectional changes between each process. 1...Disc-shaped aluminum material, 2...Rough ground product, 2a
...Ring part, 2b...Rim part, 3...Lower mold, 3
a...Concavity, 4...Upper mold, 4a...Protrusion, 5...
Molded product, 5a...Ring part, 5b...Rim part, 6
...lower die, 7...upper die, 8...conical die,
9...Lower mold, 10...Second molded product, 10a...Ring part, 10b...Opening side part, 11...Material wheel for finishing processing, W...Final product, Wa...Minimum diameter part, Wb ...Opening side.

Claims (1)

[Claims] 1. After forging a disc-shaped aluminum material into a roughly cone-shaped rough product with a ring part inclined at a predetermined angle to the rib part, this rough product is forged into a roughly cup-shaped raw product with a ring part that is almost perpendicular to the rib part. Forged into a molded product,
Next, the ring part of the molded product is narrowed inward so that it matches the minimum diameter part of the ring part of the final product, and the open side of the ring part is expanded outward to form a shape that corresponds to the final product. A method for manufacturing a forged wheel, the method comprising obtaining a material wheel for finishing processing.