JPH04167943A - Manufacture of integral type rim for light alloy-made wheel - Google Patents

Abstract

PURPOSE:To accurately manufacture an integral type rim for light alloy-made wheel for short time by forming a flange part in outside rim with forging, executing roll forming with a spinning machine after gradually forming to inside rim into thin thickness toward outer part to axial direction and finishing. CONSTITUTION:By using the light alloy of Al alloy, etc., the forging is executed and the unnecessary burr is removed to manufacture the integral type rim raw material 1 composed of a part 2 to be the inside rim, a part 3 to be the outside rim, the flange part 4 and thick part 5 and thin part 6 at center and gradually thinning toward outer part of the axial direction of the inside rim part 2. This forged stock 1 is rotated while insertion-pressing the thick part 5 and the thin part 6 with mandrels 13, 14 in the spinning machine, and the spinning is executed with the forming roller 15 to finish this to the prescribed work shape having well part 9, inclined part 10, beat sheet part 11 and flange part 12 in the inside rim. By this method, the integral type rim 8 is efficiently manufactured with the minimum material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method of manufacturing an integral rim for a light alloy wheel.

(Conventional technology and its problems) Conventionally, the method of manufacturing an integrated aluminum alloy rim for wheels was to first cut a rolled aluminum alloy plate to a certain size, then roll the plate into a ring shape and form the ends. After that, we did flash butt welding, finished the palli cant, planisosher and side burr cuts, and then
There is a method of finishing it into a predetermined shape by roll forming. However, according to this method, defects tend to occur in the welded parts, which requires air leak testing on all parts.Furthermore, the strength of the welded parts is lower than other parts, so the quality of the welded parts cannot be guaranteed. There were other problems, such as the welded part having a different specific gravity than the other rim parts, making it difficult to achieve rotational balance, and the molding process requiring multiple steps, resulting in low production efficiency.

On the other hand, as a conventional method of manufacturing an integral rim that eliminates the problematic welding process, there is a forging-roll forming method shown in FIGS. 9 to 12. The conventional method will be explained based on illustrations. First, a forged material 51 having a substantially H-shaped cross section as shown in FIG. 9 is obtained by forging. 52 is a portion that will become the outer rim in subsequent steps, 53 is a portion that will be the inner rim, and 54 is a portion that will be assembled with the disk after machining. FIG. 10 shows a process of stretching the forged material 51 in the axial direction by spinning to form an outer rim and an inner rim. 55 is the workpiece being spun, 56 is the mandrel for the outer rim, 5
7 is a mandrel for the inner rim, 58 is an outer rim portion, 59 is an inner rim portion, 6o is a central portion that is pinched by the mandrels 56 and 57 and given rotational force, and 61 is a spinning roller. FIG. 11 shows a process in which the rim portion is roll-formed into the final shape using a roll-forming machine. 62 is a roll-formed rim material, 63 is a mandrel, 64 is a roller that acts on the entire outer width of the rim, 65 is a roller that acts on the inside of the outer rim, 66 is an outer rim, and 67 is an inner rim.

FIG. 12 shows an integral sumo 8 in which the center portion of a rim material 62 (the center portion 60 shown in FIG. 10) is punched out using a press or the like. As mentioned above, the conventional manufacturing method of one-piece rims, which does not require a welding process, is effective if the wheel diameter is up to 14' and the width is up to 6'; Due to this demand, wheels have rapidly become larger in diameter and wider, and wheels with an 18' diameter and 9' width are now being manufactured.

As a result, in the conventional method, in the case of a wide rim, it is necessary to press the roller 61 against the work many times in order to obtain the appropriate rim material size in the rim during the spinning process shown in FIG. In the case of a 9' width, the time spans 10 minutes. Therefore, work hardening of the work progresses, and in order to eliminate this work hardening before the roll forming process shown in Fig. 11,
A so-called softening annealing process is required, in which the material is placed in a furnace and heated to 350'C, and maintained for approximately 1 hour. Further, even in the roll forming shown in FIG. 11, the finished diameter is unstable because the diameter is large, and in the case of an 18' diameter, the distortion can reach as much as 3 mm in diameter. Furthermore, although the outer rim portion is pressed between forming rollers 64 and 65 and gradually formed into a predetermined shape, it is impossible to provide roller 65 with the rigidity to withstand the pressure warping of roller 64 due to its cantilevered structure. Therefore, it is necessary to reduce the pressing force and take time to mold. For 18′ diameter and 9″ width,
The molding time is approximately 8 minutes, and the distortion of the outer rim is greater than that of the inner rim. For this purpose, it is necessary to make the material thick and provide sufficient cutting allowance to avoid leaving any black crust during machining in the subsequent process. Furthermore, the forming roller 64
．． 65 must be prepared according to the change in rim width and depth D of the outer rim shown in FIG.

In this way, the conventional method of obtaining an integral rim from a forged material has problems such as requiring a large amount of material weight, long processing time, and increased tool costs. The manufacturing method is based on forged materials that do not require a welding process, and aims to solve the above-mentioned problems and efficiently obtain a high-precision integrated rim in a short period of time using the minimum amount of material. .

(Means for Solving the Problems) The present invention provides a method for manufacturing an integral rim for a light alloy wheel through a hot forging process and a spinning process using a light alloy such as an aluminum alloy or a magnesium alloy. , the flange part of the outer rim is formed by forging, and the inner rim is gradually made thinner in the axially outward direction,
After that, it is finished by roll forming using a spinning machine.

Additionally, in the case of wheel specifications in which the angle of inclination of the inclined part between the well part and the beat seat part is increased to increase the amount of air inside the tire, when forming the inner rim,
Furthermore, a locally widened notch is provided inside the distal end portion for molding.

(Function) In the method for manufacturing an integrated rim of the present invention, only the inner rim part of the rim material formed by forging as described above is finished into a predetermined size and shape by spinning, and the outer rim is left as it is formed by forging. In this state, spinning is not necessary, and the spinning roller can be used for rims of any size, regardless of rim diameter or rim width. If the slope between the well part and the beat seat part has a steep angle of inclination, the tip of the inner rim is expanded locally so that the inner rim can fully follow the mandrel during spinning. Since it has a section, spinning processing can be carried out smoothly in a short time.

(Example) Embodiments of the present invention will be described based on FIGS. 1 to 8.

1 in FIG. 1 shows a one-piece rim material that has been forged and has had unnecessary edges removed. 2 is the part that will become the inner rim in the next spinning process, 3 is the outer rim, and 4 is the outer rim 3.
The flange section is shown. Reference numeral 5 indicates a thick wall portion that is assembled with the disk after machining, and 6 indicates a thin wall portion at the center, which is a so-called scrap portion that is punched out using a press or the like after the spinning process. FIG. 2 is an enlarged view of part A of the forged material 1, that is, a cross-sectional view of the forged material 1 in the axial direction. The outer rim 3 and the flange 4 are completely formed by forging, and the inner rim portion 2 is given an angle of α° on the outside and β° on the inside so that it becomes gradually thinner toward the outside in the axial direction. . These angles vary slightly depending on the rim width, but α° is approximately 2° and β° is approximately 5°.The I11 forged and spinning upper base were good.

FIG. 3 shows a spin-molded one-piece rim 8. The forged material 1 is rotated with its central thick part 5 and thin part 6 pressed together by mandrels 13 and 14 of a spinning machine. The forming roller 15 performs spinning forming by moving as shown by the arrow on the portion that will become the inner rim portion of the forged material 1 shown by the two-dot chain line. The movement of the roller 15 is controlled by a hydraulic/electrical servo mechanism (not shown) or the like to finish the work into a predetermined shape. 9 is a well portion, 10 is an inclined portion where the well portion 9 transitions to the beat seat portion 11, 12 is a flange portion of the inner rim formed by spinning, and t2 is the thickness thereof. FIG. 4 shows an example of an assembly type wheel using an integral rim manufactured according to the present invention. After the integral rim 8 has been subjected to spinning processing, the thin-walled central portion 6 is removed by a press or the like, and then heat treated and machined. Completed through processes such as processing and painting, 19 is the outer rim part of the same rim, 20 is the inner rim part, 21 is the disc, and 22 is the fixing bolt etc. that fastens the integrated rim 8 and the disc 21. It is a child. The differences between the conventional method and the method of the present invention in manufacturing an integral rim for sizes 18' and 91 in this embodiment are as follows.

Next, the invention shown in claim (2) will be explained.

What is shown in FIG. 5 is a forged material for a wheel with a steep angle of inclination between the well part and the beat seat part. Part 2
A notch 7 that is locally enlarged at an angle θ° is formed on the inside of a. θ° is determined by the thickness tl of the tip, the degree of inclination σ° of the inclined part 10 from the well part to the beat seat part 11 in FIG. If ° is 75°, then θ.

The best molding conditions were 30'' to 45°, and 9mm for 1.

In FIG. 6, the tip 2a of the inner rim 2 is connected to the mandrel 1.
3 shows the state immediately before climbing over the slope 10a. Unlike conventional roll forming methods that use forming rollers that act on the entire rim, the present invention uses one or more forming rollers to spin only the inner rim portion to obtain a predetermined inner rim shape. It is necessary to devise a way for the well portion 9 to overcome the slope portion 10a in front of the portion 11a where the beat sheet portion 11 is formed. This problem was solved by forming a local notch inside the tip of the inner rim portion 2. This is because the cutout part 7 comes into contact with the inclined part 10a and the roller 15 moves along the trajectory shown by the arrow, so that the tip part 2a of the inner rim material is lifted up to the beat sheet part forming part 11a of the mandrel 13, and then Roller 1 on page
A flange of the inner rim portion is formed by the action of step 5. FIG. 7 shows an assembled wheel using the above-mentioned partial type rim. If the notch 7 at the tip of the inner rim part does not exist, as shown in Fig. 8, the position shown in Fig. 1 should be reversed by 180 degrees and turned upside down, that is, with the outer rim part 3 facing down. A process called flaring is required, in which the mold 17 is inserted into the inner diameter side of the inner rim 2 and applied in the direction of the arrow to widen the tip of the inner rim 2. This requires a hydraulic press weighing more than 100 tons, and it also takes time to process the flaring. In FIG. 6, the movement of the roller 15 is shown to be completed in one movement along the trajectory of the arrow, but in reality, the movement of the roller 15 is
Since the wall thickness of the material is nearly 2.5 times the thickness at the end of the spinning process, the roller 1 must be repeated 3 to 4 times before the inner rim 20 is formed into the shape shown in FIG.
5 on the inner rim. However, at this time, it is important that the rollers 15 do not act on the tip end 2a, but act only once from the state shown in FIG. 6 to get over the slope 10a at once. Of course, this spinning process can be performed using multiple rollers at the same time, and in the example, three rollers were used at the same time, so even a partial rim with a diameter of 18' and a width of 9' can be completed in just 3 minutes. This spinning process was completed.

In the manufacturing method of the present invention as described above, the precision of the part-type rim after spinning is good, and the distortion is 0.7 mm in the inner rim part and 0.7 mm in the outer rim part with the same 18' diameter and 9' width. It was 0.5■. Therefore, significant material savings were achieved compared to conventional methods.

(Effects of the Invention) According to the manufacturing method of some types of rims of the present invention, the forging time is increased by about 25% compared to the conventional method, but the effect of reducing material weight, machining, etc. is large, and overall cost is reduced. This is an advantageous manufacturing method that can reduce the cost by about 25% compared to conventional methods.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the cut end of a quarter of a part-type rim material that has undergone the forging process, and Fig. 2 is an enlarged cross-sectional view of part A in Fig. 1. Fig. 3 is a side view, partially in section, showing a spun part-formed forged rim, and Fig. 4 is a side view, partially in section, showing an example of a completed assembled wheel. 5 is an enlarged view of another example specification wheel of a portion corresponding to the cross section of part A in FIG. 1, and FIG. 6 is a sectional view showing the spinning state of the tip of the inner rim. Fig. 7 is a side view partially showing a completed prefabricated wheel separately, Fig. 8 is a longitudinal sectional view showing the flaring process of the integral rim material, Fig. 9 10 is a cutaway perspective view showing a part-type rim material in a conventional method, FIG. 10 is a partially cross-sectional side view showing the spinning process, and FIG. 11 is a roll forming process. FIG. 12 is a side view partially in cross section showing the completed rim. FIG. Explanation of symbols 1...Integrated rim material 2...Part that becomes the inner rim

Claims (2)

[Claims] (1) In a method of manufacturing an integral rim for a light alloy wheel using a light alloy such as an aluminum alloy or a magnesium alloy through a hot forging process and a spinning process, the flange portion of the outer rim is formed by forging. A method of manufacturing an integrated rim for a light alloy wheel, which is characterized in that the inner rim is gradually thinned axially outward, and then finished by roll forming using a spinning machine. (2) When forming the inner rim, further inside the tip,
2. The method of manufacturing an integral rim for a light alloy wheel according to claim 1, wherein the molding is performed by providing a locally widened notch.