JPS6146217B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a rim made of aluminum alloy (hereinafter referred to as Al alloy) used for bicycles, motorcycles, etc.

More specifically, a ring-shaped material made of Al alloy 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 above-mentioned mold , while gradually reducing the distance between the rolls and rotating the mold and rolls, rolling and forming the material while restricting the outer diameter dimension,
The volume of the above-mentioned material is set to be more than the predetermined volume at the time of completion, and the excess material during molding is made to protrude to the sides of the molding groove between the mold and the rolls and becomes fluff (excess material) to prevent variations in the volume of the material. without being influenced
The present invention relates to a method for manufacturing an Al alloy rim that enables highly accurate rolling forming of the Al alloy rim.

Seamless in vehicles such as bicycles and motorcycles
A method for manufacturing an Al alloy rim is already known from Japanese Patent Application Laid-open Nos. 49-43868 and 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 forming rolls facing each other at the outer diameter, and one roll is moved in the direction of the other roll to gradually reduce the distance between the rolls and rotate. The material is rolled to form a predetermined cross section, and the diameter of the material is thereby expanded, and expansion restraint during molding is performed by guide rolls placed on the circumference of the material to be formed.

The conventional seamless rim manufacturing method as 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, and there are Since the guide rolls provided to restrict the outer diameter are only partially provided on the circumference, it is difficult to obtain accurate outer diameter dimensions and roundness of the molded rim, and twisting may occur. do. For this reason, after forming the rim, it is necessary to correct the above-mentioned outer diameter dimension, roundness, and even torsion, which increases the number of man-hours, makes the work troublesome and complicated, and requires extra equipment and effort. Mass production of rims without rims is not desirable in terms of cost.

In addition, as mentioned above, plastic deformation in the direction of diameter expansion is overwhelmingly high during molding, so if there is variation (non-uniformity) in the volume of the ring-shaped material,
This variation occurs as a variation in the diameter when the molding is completed, and the above-mentioned correction process is required. Especially when the volume is somewhat small, it is difficult to obtain a desired cross section with high precision, and there are parts with small thickness. This results in molding defects such as shrinkage. Therefore, it is necessary to strictly control the cross-section, volume, etc. of the material, but it is difficult to do so in practice, and since the molding is also as described above, there is no correction process, and there is no need for a correction process, and it is difficult to carry out this in practice. It is not possible to immediately and easily obtain a seamless Al alloy rim with no seams using conventional means.

In particular, the present inventor has effectively and fundamentally solved the above-mentioned problems in the conventional manufacturing method of seamless rims, especially the problems of outer diameter dimension, roundness, etc., and the problem of poor molding, and has achieved truly useful results. The present invention has been made to provide a method for manufacturing an Al alloy rim.

The object of the present invention is to interpose a ring-shaped material made of Al alloy between a rotatable mold set to the external shape of a rim and a rotatable reduction roll provided inside the mold. , the distance between the mold and rolls is gradually reduced, and the mold and rolls are rotated to perform rolling forming while constraining the outer diameter of the material, and the volume of the material is increased to a point where the volume of the material is sufficiently larger than the predetermined volume at the time of completion. To provide a method for manufacturing an Al alloy rim, in which the extra material is set to be extra, and the excess material at the time of completion of forming is made to protrude to the side of the forming groove between the mold and the rolls to form a flash (excess material).

Therefore, an object of the present invention is to obtain an Al alloy rim having a predetermined cross section with high precision, which is not affected by variations in the volume of the material and which does not cause molding defects such as sink metal. We provide a manufacturing method that can

Further, the object of the present invention is to maintain the predetermined cross section with high precision as described above, maintain the outer diameter dimension and roundness by restricting the outer diameter with the mold, and produce aluminum without twisting.
Alloy rims can be formed, and only the above-mentioned flash removal process eliminates the need for subsequent troublesome and complicated straightening processes. This dramatically simplifies the production of this type of rim, and reduces costs for mass production. To provide a manufacturing method for obtaining an alloy rim which is extremely favorable in terms of aspects as well.

Furthermore, it is an object of the present invention that by setting an extra volume of the space material, management of the cross section, volume, etc. of the material is unnecessary or simplified, which is also advantageous in this respect, and the above-mentioned method reduces the problem of minced meat, etc. To provide a method for manufacturing the above-mentioned rim, which eliminates the occurrence of defective molded products and has an extremely high product yield.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

1 to 4 are explanatory diagrams of the manufacturing method according to the present invention, FIG. 1 is a diagram showing the relationship between the mold and the reduction roll and the set state, and FIG. An enlarged sectional view, FIG. 3 is a view similar to FIG. 2 with the mold and reduction roll closed, and FIG. 4 is a view similar to FIG. 2 when molding is completed.

In the above figure, 1 is a male mold, and the inner diameter part 2 of the mold 1 is provided with a perfectly circular molded part 3. This molded portion 3 is designed to match the shape and outer diameter of the final product of the rim.

The shape of the molded portion 3 is configured to match the outer diameter side of the cross-sectional shape of the rim to be molded.

That is, a protrusion 4 forming a drop part in the center,
A flat part 5 forming a bead receiving part on both sides of the flat part 5, a rising wall 6 falling radially outward from both sides of the flat part 5 and forming an ear part on both sides, and a recess 7 at the base of the rising wall 6. It consists of guide walls 8 formed on both sides of the mold and facing outward, forming a male mold.

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 its axis of rotation is parallel to the center line of rotation 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.

And the inner diameter part 2 of the mold 1 of the reduction roll 11
A female molded part 13 corresponding to the molded part 3 is provided on the outer diameter part 12 facing the molded part 3 .

That is, 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, the reduction roll outer diameter forming part 13 has a female mold with a concave intermediate part in the width direction, and has a chevron-shaped guide part 18 corresponding to the guide wall 8 on the outermost side, and a taper facing the above-mentioned recess 7 on the inside thereof. part 17, a raised wall 16 that is continuous with this on the inside, and a flat part 1 that is continuous with this on the inside
5. It has a recess 14 facing the projection 4 in the center. In the illustrated embodiment, a concave strip 19 is provided in the center of the concave portion 14 to form a foot portion of the inner diameter portion of the rim.

In the above, when the inner and outer reduction rolls 11 and the mold 1 are in the final closed state, that is, when the distance between them is the smallest at the time of completion of molding, they are surrounded by the molding parts 3 and 13 as shown in FIG. The setting is such that an escape space S is formed by side guide portions 8 and 18 on the sides of the molding space, which opens outward and communicates with the above space.

A thick material W is placed between the reduction roll 11 and the mold 1, and the material W is separated from the raised wall 16 of the molding part 12 of the reduction roll 11 and the flat part. It is set so that a part of it is supported by a part of the recess surrounded by 15.

The material W has a substantially thick ring shape that allows for shearing deformation, has a smaller diameter than the mold 1, and is rolled by the reduction roll 1.
It has a sufficiently larger diameter than No. 1 and is molded from an Al alloy material. The ring-shaped material W may be cast, or may be a material drawn into a cylindrical shape, extruded, etc., and cut into a predetermined width. has been completed.

The most important thing about the material W is that the volume of the material W should be set to be sufficiently larger than the predetermined volume at the time of completion when the material is formed into a predetermined cross section.

The material W is placed between the reduction roll 11 and the mold 1 as described above, and the reduction roll 11 is moved in the direction of the mold 1. Figures 1 and 2 show the state just before the start of molding. showed that. Then, the mold 1 is driven to rotate in the counterclockwise direction in the drawing shown by the arrow B, and the reduction roll 11 is moved in the direction of the mold 1 to gradually narrow the gap between them. The reduction roll 11 rotates counterclockwise through the material W, and the material W between the die 1 and the reduction roll 11 is fed in the same direction. Thus, the cross section of the material W has the molded parts 3 and 13.
It is gradually rolled and formed into a predetermined cross section between the steps. In combination with this, the diameter of the material W is expanded, and the degree of expansion deformation of this diameter is extremely high. This diameter expansion deformation 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 size outer diameter of the material W as described above, rolling plastic deformation The expansion deformation of the outer diameter caused by this is maintained at the final outer diameter dimension.

In this way, a molded article _W1 is obtained.

In the above, since the volume of the material W is set to be sufficiently extra than the predetermined formed cross section at the completion of forming, even though the plastic deformation in the direction of diameter expansion is overwhelmingly high as described above, When a predetermined cross section is completed, excess meat is actively generated, and this extra meat protrudes laterally from the relief space S at the side formed when the molding parts 3 and 13 are closed, resulting in a flat surface W _{2 .} will be formed.

In this way, since the flash W ₂ is actively molded to protrude from the sides of the molded parts 3 and 13,
When molding is completed, molding defects such as sink metal do not occur. Since the setting is made to actively form the flash W ₂ , even if there is variation in the material within the above range, it can be formed with high precision into a predetermined cross section without being affected by this. Since flashing occurs when molding is completed, this can be visually checked from the outside to confirm that molding is complete. Furthermore, since molding is carried out while restricting the outer diameter with the mold 1, the outer diameter dimension and roundness are maintained at extremely high precision, there is no twisting, and only the removal of flashing is required afterward, and straightening is required. No process required.

The seamless rim 30 obtained in the above manner is as shown in FIG. 5, with left and right ear pieces 31 and 32 raised on both sides, tire bead receiving parts 33 and 34 inside these, and a drop part 35 in the center. , and the drop part 35
A completely seamless rim 30 is obtained with a foot 36 projecting radially inwardly at the center of the rim width. The overall longitudinal section and side surface of this are shown in FIGS. 6 and 7. In the figures, 37 is the air valve attachment 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

The illustrated embodiment has been described above with respect to manufacturing a rim having a foot portion 36, but it goes without saying that a rim 30a having a normal cross-sectional shape as shown in FIG. 8 can also be molded. By changing the cross-sectional shapes of the parts 3 and 13, a rim with an arbitrary cross-sectional shape can be obtained.

FIG. 9 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 46 is configured to be movable forward and backward by a slider 48, and can be raised and lowered by a roll-down cylinder 49. has been done.

In this embodiment, as described above, the embodiment is applied to a seamless rim, but it goes without saying that the aluminum alloy missing circular material can be joined by welding or the like, and the material formed into a ring shape can be rolled into a rim shape.

According to the present invention as described above, a ring-shaped material made of Al alloy is interposed between a mold set to the external shape of the rim and a reduction roll provided inside the mold, and the mold and the roll are rotated. The rolls are moved to form the material into a predetermined cross section in the molding section between the two, and the outer diameter of the material is constrained while being rolled and formed, and the volume of the material is set to be sufficiently larger than the predetermined volume at the time of completion. Since excess material at the time of completion of molding is allowed to protrude to the side of the molding section between the mold and the rolls to form a flash, molding can be performed without molding defects such as shrinkage.

In particular, as mentioned above, the volume of the material is set to be excessive, and flashing is actively caused, so even if there is variation in the material within the above range, the occurrence of molding defects such as shrinkage can be eradicated. In rolling forming a rim that undergoes extremely high plastic deformation in the direction of diameter expansion, a rim having a highly accurate cross-sectional shape can be reliably obtained, and the product yield in this respect can be significantly improved.

In addition, the present invention achieves the above and performs rolling forming while restricting the outside diameter to the final product size using a mold, thereby maintaining high accuracy of the outside diameter and roundness, and producing a highly accurate rim without twisting. Therefore, it is possible to form the rim with a simple and easy operation, and then the product can be obtained immediately without going through the troublesome and complicated straightening process, which only requires the removal of the flash, making it possible to manufacture seamless rims. It is possible to manufacture high-precision Al alloy rims while making it dramatically simpler and easier.

Furthermore, in the present invention, since the flash is actively molded as described above, the flash can be visually checked from the outside during molding to confirm the completion of molding, which is also advantageous for work management, etc., and facilitates rim molding. In combination with the above, this will greatly contribute to the mass production and cost reduction of this type of rim.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS. 1 to 4 are explanatory diagrams of the manufacturing method of the present invention.
The figure shows the relationship between the mold and the reduction roll and the set state, Figure 2 is a sectional view taken along the line 2-2 in Figure 1, Figure 3 shows the mold and the reduction roll in a closed state, and Figure 4 is a view similar to FIG. 2 when molding is completed, FIG. 5 is an enlarged sectional view of the obtained rim, FIG. 6 is a longitudinal sectional view of the entire rim, FIG. 7 is a side view of the same, and FIG. FIG. 9 is a diagram showing an example of a modified rim, and FIG. 9 is a diagram showing an example of a specific molding machine. In addition, in the drawing, 1 is a mold, 11 is a reduction roll, W is a raw material, W ₁ is a molded product, W ₂ is a flash, 30, 3
0a is the rim.

Claims (1)

[Claims] 1. The above rim is placed in a rotatable mold provided with a molded part that follows the outer peripheral shape of the rim, which has ears extending radially outward and feet projecting radially inward. A rotatable rolling down roll is positioned which has an outer circumferential surface that follows the inner peripheral shape and communicates the molding space with the excess thickness relief space at a narrow portion together with the mold when the mold is closed, and the rolling down roll and the mold are connected to each other. In between, a ring-shaped material made of aluminum alloy with a relatively thick wall, which has a diameter smaller than the inner diameter of the mold, a diameter sufficiently larger than the reduction roll, and a volume sufficiently larger than the volume of the completed rim, is set, and Either the mold or the reduction roll is rotated, the reduction roll is moved, and the material is rotated, and the material is rolled and formed by the pressure action of the reduction roll, so that the diameter of the material is gradually expanded. The aluminum flows into the inside of the molding space to form the foot part, and furthermore, the squeezing action in the narrow part actively provides resistance to the flow of the material to fill the missing thickness of the ear piece and make it protrude as a flat. Method of manufacturing alloy rims.