JPS6150697B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rim made of aluminum alloy (hereinafter referred to as Al alloy) used for bicycles, motorcycles, etc.
In particular, it relates to a method suitable for manufacturing seamless rims with no seams.

More specifically, a ring-shaped Al alloy material is interposed between a rotatable mold set to the external shape of the rim and a rotatable reduction roll provided inside the mold, and the mold or One side of the reduction roll is driven to rotate and the reduction roll is moved toward the mold, and the above material is rolled and formed while the outside diameter is constrained by the mold, creating a seamless Al alloy rim without any subsequent straightening. The present invention relates to a method of manufacturing a seamless rim that can be molded while maintaining a predetermined outer diameter dimension and a predetermined cross-sectional shape with high precision so that the seamless rim is not required.

Seamless in vehicles such as bicycles and motorcycles
The method for manufacturing Al alloy rims is disclosed in Japanese Patent Application Laid-Open No. 49-43868.
This is already known from Japanese Patent Application Laid-Open No. 51-42065.

The manufacturing method for this type of seamless Al alloy rim is as follows:
In each case, a ring-shaped material is interposed between a pair of rolls facing each other at the outer diameter, and one roll is moved toward the other roll to gradually reduce the distance between the rolls and rotate, thereby rolling the material between the rolls. The material is formed into a predetermined cross section, and the diameter of the material is thereby expanded, and expansion restraint during molding of the material is performed by guide rolls placed on the circumference of the material to be formed.

The conventional seamless rim manufacturing method described above has the following problems.

In other words, since the ring-shaped material is rolled between the rolls as described above, the plastic deformation of the material is overwhelmingly high in the direction of diameter expansion, and as a result, the diameter may exceed a predetermined size while the cross-sectional shape of the rim is incomplete. Resulting in.
Therefore, it is necessary to adjust the above-mentioned rolling so that the diameter of the rim is formed to a predetermined size at the same time that the cross-sectional shape of the rim is completed, but it is extremely difficult to adjust the timing of this process, and it is difficult to adjust the timing of this process. Since the guide rolls for restricting the outer diameter provided on the rim are only partially provided on the circumference, it is difficult to obtain accurate outer diameter dimensions and roundness of the molded rim, and moreover, it is prone to twisting, etc. Occur. For this reason, a straightening process is required after the rim is formed, and this work is troublesome and complicated, and when combined with the above-mentioned forming, the number of man-hours inevitably increases, and additional equipment and equipment are required.
Mass production of seamless rims requires extra labor,
Unfavorable in terms of cost. Although it is conceivable to increase the number of guide rolls in the conventional means described above, it is difficult to expect a fundamental solution to the above problem even if the number of guide rolls is increased, and the structure of the forming apparatus will only become unnecessarily complicated.

In particular, in view of the above-mentioned problems in the conventional manufacturing method of seamless rims, the present inventor has effectively solved the problem by
The present invention has been made in order to fundamentally solve the problem and provide a truly useful method of manufacturing a seamless rim.

The object of the present invention is to form a ring-shaped mold between a rotatable mold set in the shape of the outer diameter of the rim and a rotatable reduction roll provided inside the mold.
An Al alloy material is interposed, one of the mold or the reduction roll is rotationally driven, and the reduction roll is moved toward the mold, and the material is rolled between the mold and the roll to form a predetermined cross-sectional shape. In addition, manufacturing a rim in which deformation in the direction of expanding the diameter of the material to be molded is restrained by a mold set to the final shape and dimensions of the product, and the outside diameter of the material is restrained by the mold while being rolled. provide a method.

Therefore, the object of the present invention is to mold the material while constraining the outer diameter of the material to the shape and dimensions of the final product using a mold, so that the precision of the outer diameter and shape of the obtained product can be extremely high. To provide a rim manufacturing method capable of forming a seamless rim while accurately maintaining predetermined outer diameter dimensions, cross-sectional shape, and roundness with high precision.

Further, the object of the present invention is that since the product obtained as described above can maintain high precision, there is no need for any subsequent straightening processes such as outer diameter straightening, roundness straightening, and twist straightening. It is possible to obtain a truly useful manufacturing method that can be used as a product immediately after only one step and can provide a high-precision rim with only one step.

Furthermore, the present invention allows the final product to be molded in one step as described above and does not require a straightening process, so the rim can be obtained with a reasonably minimum number of man-hours while maintaining high precision and improving quality. This reduces man-hours and simplifies manufacturing when manufacturing seamless rims.
The purpose is to provide a truly useful and novel method for manufacturing seamless rims that facilitates production, improves mass production, and reduces costs, and that completely and completely solves the problems of conventional methods. .

Furthermore, the object of the present invention is to interpose the material between the mold and the roll-down roll provided in the mold as described above, and simply drive the mold to rotate and roll down the roll. The molding process is easy, and since the outer diameter is constrained during molding, there is no need for any adjustment during processing, and a seamless rim can be molded as described above by simply adding and setting the materials. Therefore, work management etc. are also simplified and facilitated, and a method is also provided in which the above-mentioned high-precision seamless rim can be manufactured with simple work.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 are explanatory diagrams of the manufacturing method according to the present invention, where FIG. 1 is a diagram showing the relationship between the mold and the reduction roll and the set state of the material, and FIG.
The enlarged sectional view taken along two lines in FIG. 3 is a view similar to FIG. 2 after completion of molding.

In the above figure, 1 is a mold, and the mold 1 has a perfectly circular molded part 3 on its inner diameter part 2.
The perfectly circular shaped part 3 is set to match the shape and outer diameter of the final product of the rim, and the shape of the shaped part 3 is configured to match the outer diameter side of the cross-sectional shape of the rim to be molded. There is. That is, for example, a protrusion 4 that forms a central drop part, a flat part 5 that forms a bead receiving part on both sides of the protrusion 4, and a flat part 5 that falls radially outward from both sides of the flat part 5 to form ears on both sides. A wall 6 is provided, which constitutes a male mold provided over the entire circumference of the inner diameter part of the molded part 3.

A roll-down roll 11 is disposed within the inner diameter portion 2 of the mold 1, which is the outer mold, and the roll-down roll 11 is freely rotatable, and the axis of rotation is parallel to the rotation center line of the mold 1. It is configured to be movable in the direction of the inner diameter of the mold 1 as shown by arrow A. The outer diameter portion 1 of the reduction roll 11 is opposite to the inner diameter portion of the mold.
2 has a female molding part 13 corresponding to the molding part 3 described above.
is provided. This molded portion 13 is configured to fit the inner diameter side of the cross-sectional shape of the rim to be molded. That is, a recess 14 corresponding to the protrusion 4 is provided in the center, flat parts 15 are provided on both sides of the recess 14, and flat parts 1
Raised wall portions 16 are provided on both sides of the recess 14 , and a recess 17 is provided in the center of the recess 14 , and this molded portion 13 is provided over the entire circumference of the outer diameter portion 12 .

In the above, the reduction roll 11 is separated from the mold 1, the thick material W is put between the reduction roll 11 and the mold 1, and the material W is placed between the flat part 15 of the molding part 13 of the reduction roll 11. Set it so that it is partially supported. The material W was set, the reduction roll 11 was moved in the direction of the mold 1, and the state immediately before molding is shown in FIGS. 1 and 2.

As shown in FIGS. 2 and 3, the material W has a ring shape with a considerable thickness considering the volume of the completed rim after plastic deformation, and is smaller in diameter than the mold 1 and sufficiently thicker than the reduction roll 11. It has a large diameter and is made of Al alloy. The ring-shaped material may be cast, or it may be a material drawn into a cylindrical shape, extruded, etc., and then cut into a predetermined width.It shall be obtained by an appropriate method, and a seamless ring-shaped material may already be formed at the material stage. are doing.

The material W is loaded and set as described above, and the mold 1 is rotated counterclockwise as shown by the arrow B from the state shown in FIGS. 1 and 2. As a result, the roll 11, which is rotatably supported and in contact with the mold 1 via the material W, rotates counterclockwise, and the material W between the mold 1 and the reduction roll 11 is fed in the same direction. The reduction roll 11 is moved in the direction of the inner diameter of the mold 1 as indicated by arrow A, and the distance between the molded parts 3 and 13 is gradually reduced. As a result, the cross-section of the material W is gradually rolled into a predetermined cross-sectional shape between the molding parts 3 and 13. In addition to this, the material W expands its diameter due to rolling plastic deformation between the molded parts 3 and 13 of the material W, and the degree of expansion deformation of this diameter is extremely high. This expansion deformation of the diameter is regulated and restrained by the inner diameter part 2 of the rotatably driven mold 1, and since this inner diameter part 2 is set in advance to the final dimension outer diameter of the material W as described above,
The expansion deformation of the outer diameter due to rolling plastic deformation is maintained at the final dimension outer diameter. Therefore, as shown in FIG. 3, the material _W1 formed into the cross-sectional shape of the final product between the molding parts 3 and 13 has an outer diameter determined in advance as shown by the imaginary line _W1 in FIG. It is then molded to the final dimensions.

In this way, the ring-shaped material is rolled into a predetermined cross-sectional shape and the outer diameter of the final product using the mold 1 and the reduction roll 11. In the above-mentioned molding, no adjustment of the cross-sectional shape and the rim outer diameter is required at the time of molding because the molding is performed while constraining the outer diameter.

The product W ₁ thus obtained has a predetermined cross section,
The outer diameter dimension is maintained with high accuracy, and the roundness is also high.
There is no twisting, and therefore, there is no need for any process of correcting the outer diameter or roundness as in the past.

The seamless rim 30 obtained in the above manner is as shown in FIG.
A completely seamless rim 30 is obtained, which has a drop part 35 in the central part, and a foot part 36 projecting radially inward at the center of the drop part 35 and in the middle of the rim width. The entire longitudinal section and side surface of this are shown in Figs. 5 and 6. In the figures, 37 is the air valve mounting part when the rim is made into a tubeless wheel, and a part of the foot part 36 is removed. can be easily obtained by

Although the illustrated embodiment describes the manufacture of a rim having a foot portion 36, it is of course possible to mold a rim 30a having a normal cross-sectional shape as shown in FIG. By changing the cross-sectional shapes of the molded parts 3 and 13, a rim with an arbitrary cross-sectional shape can be obtained.

FIG. 8 shows a specific embodiment of the molding machine used for the above molding, in which the mold 1 consists of a plurality of divided pieces that expand outward in the radial direction, and enables the material to be discharged after molding. Drum-shaped die spindle 4
0, the die spindle 40 is supported by the motor 4
1. It is driven by a reduction gear 42, a pinion 43, and a gear 44 provided on the spindle side. The roll-down roll 11 is supported by a roll spindle 45, and the spindle 45 is rotatably supported by a drum-shaped spindle case 46 with a bearing 47. The case is configured to be able to move forward and backward with a slider 48, and can be raised and lowered with a roll-down cylinder 49. ing.

In the embodiment shown above, the mold 1 is rotationally driven and the reduction roll 11 is freely rotatable, but this relationship may be reversed.

In this example, an example applied to a seamless rim has been described, but it is of course possible to join the missing circular materials of Al alloy by welding or the like and form the material into a ring shape, and then roll the material into a rim shape.

As is clear from the above, according to the present invention, the inner diameter of the mold is set to the final outer diameter of the rim, a reduction roll is disposed inside the roll, and the roll is movable.
Both are configured to be rotatable, with a ring-shaped structure between them.
By interposing an Al alloy material, one side is rotated and the other is moved in a direction that gradually narrows the distance between the two, and the material is rolled and formed, so the material is formed into a predetermined cross-sectional shape between the die and the reduction roll. This diameter expansion is constrained by the dimensions of the final product due to the inner diameter of the mold. Therefore, the outer diameter of the product after molding is maintained with extremely high accuracy, and the cross section is free from twisting. It is possible to obtain an Al alloy seamless rim with extremely high precision in outer diameter and roundness.

Therefore, it is possible to create a seamless rim with excellent precision in a predetermined cross section and outer diameter in a single process without going through the troublesome and complicated straightening process of correcting outer diameter dimensions, roundness, torsion, etc. as in the past after molding. It is possible to easily and reliably manufacture seamless rims with a minimum of man-hours, and this is a major contribution to mass production of this type of rims and cost reduction.

Furthermore, since the above-mentioned rim is formed while the outer diameter is constrained by a mold, there is no need to adjust the timing of shaping the cross-sectional shape of the rim or expanding the diameter, and adjustments can be made automatically by setting the materials. This allows for easier molding work, easier work management, and automation of the molding work.

Furthermore, in the present invention, the mold and the reduction roll provided in the mold are operated as described above to obtain the rim, so that the molding machine itself can have a relatively simple structure, and no straightening equipment is required. Together with this, it is possible to manufacture truly useful and economical rims.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and Figures 1 to 3 explain the manufacturing method according to the present invention. Figure 1 shows the relationship between the mold and the reduction roll and the set state of the material. The figure shown in Figure 2 is Figure 1 2-2.
Line sectional view, Figure 3 is a view similar to Figure 2 when molding is completed, Figure 4 is an enlarged sectional view of the molded rim, Figure 5
The figure is a vertical sectional view of the whole, Figure 6 is a side view of the same, and Figure 7 is a longitudinal sectional view of the same.
The figure is a diagram showing a modified embodiment of a rim manufactured by the present invention, and FIG. 8 is a diagram showing a specific embodiment of a molding machine used in the present invention. In the drawings, 1 is a mold, 10 is a reduction roll, W is a raw material, and 30 is a rim.

Claims (1)

[Scope of Claims] 1. In a rotatable mold having a male molding part shaped to follow the outer peripheral shape of the rim to be formed on the inner peripheral surface,
A rotatable rolling down roll having a female molding part formed on the outer periphery that follows the inner peripheral shape of the rim is positioned, and a central part is placed in the female molding part of the rolling roll so as to correspond to the male molding part of the mold. A recessed portion and two flat portions extending from both ends of the recessed portion to both raised walls outward thereof are formed, and a female molding portion of the reduction roll is formed between the reduction roll and the die and has a diameter smaller than that of the die. A ring material made of aluminum alloy with a diameter larger than the diameter of the rim and having a considerable thickness considering the volume of the completed rim after plastic deformation is provided, and the end portion of the ring-shaped material is molded into the female mold of the reduction roll. The material is supported and set on a part of the inner side of each of the two flat parts of the section, and either the mold or the reduction roll is rotated, and the reduction roll is moved while rotating the material. A method for manufacturing an aluminum alloy rim, in which the diameter of the material is gradually expanded by rolling and forming the material by the pressure action of the material, and the material is rolled and formed while restraining expansion deformation of the material using the mold.