JPS6186037A - Manufacture of hollow section rim - Google Patents

Abstract

PURPOSE:To form a hollow aluminum alloy rim of a light weight to a prescribed annular shape by forming a part or the whole of a section hollow part so that it becomes a little larger than a prescribed finish size by means of extrusion forming of an aluminum alloy, pressing and deforming it by roll-forming, and setting the hollow part to a prescribed shape size. CONSTITUTION:A hollow part 11 can be formed easily by extruding a part or the whole of a hollow rim section hollow part 11 so that it becomes a little larger than a prescribed size by extrusion forming of an aluminum alloy. It is pressed and deformed by roll-forming, and the hollow part 11 is formed to a prescribed shape size, also curved to an annular shape and formed to a butt ring shape. In case of only a conventional extrusion forming, a size section of the hollow part 11 cannot be made so small, the rib becomes large and its conversion to a light weight is insufficient, but according to this method, it is converted to a light weight easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to a method for manufacturing a hollow cross-section rim, in particular a type of rim with a small gap in the hollow portion.

(Prior art and its problems) Normally, the rim is made by forming a 7-gage material with a constant width into a predetermined cross section, then bending the whole into an annular shape and joining the joint ends together by means such as welding, or Alternatively, a method is adopted in which a long material formed into a predetermined cross section by extrusion molding is bent into an annular shape as it is, and the joint ends are joined to each other.

In the rims specified in JIS-D-9421, quizzes of WO-1 to 4 process steel plates using the former method to create rims.

In order to reduce the weight, it is conceivable to change the material to aluminum or aluminum alloy and adopt the latter manufacturing method.

However, with this method, sufficient weight reduction cannot be achieved.

The reason for this will be explained by taking the cross-sectional shape of WO-2 and WO-4 (FIG. 4) as an example.

When forming a predetermined hollow cross section by compression molding, the minimum gap between the hollow parts must be set to at least about 2.5M. On the other hand, when changing the material from a steel plate to an aluminum alloy, the thickness of the plate may be set larger than that of the steel plate for reasons of strength.

Therefore, we bent an extruded aluminum material into a ring shape to form a rim (
! - When adopting the manufacturing method, the outer shape must be set while maintaining the dimensions in relation to the tire, resulting in a cross section as shown in FIG. 7.

In this case, due to constraints from the above-mentioned gap, plate thickness, and securing internal dimensions, the external width becomes larger than that of conventional steam rims, and the riding distance increases accordingly.

Therefore, despite using light materials.

As a result, sufficient weight reduction cannot be achieved.

(Technical Problem) The present invention aims to further reduce the weight of the entire rim with a hollow cross section by bending an extrusion molded material as a starting material. The task is to apply pressure so that the minimum gap in the hollow part can be set smaller.

(Means) The technical means of the present invention for solving the above problem is to set in advance the dimension of a part or all of the hollow part of the cross section of the extrusion molding material to be larger than the finished dimension, and to A part or all of the hollow part is reduced to the finished size by pressure deformation by roll forming.

(Function) The above-mentioned technical means of the present invention works as follows.In the extrusion molding mold material, the minimum gap of the hollow part is set to be large due to the above-mentioned constraint force, but in the annular roll forming process, The hollow part is reduced and the finished cross-sectional shape Kt1. Shaped.

Therefore, in extrusion molding. Regardless of the constraints from the mold structure, the minimum gap in the hollow portion can be set small, and in extreme cases, partial KIMl gaps can be eliminated.

(Effects) Since the present invention has the above configuration, it has first-order unique effects.

Since the minimum gap in the hollow part can be set small, it is possible to arrange a predetermined wall thickness of light alloy within the cross-sectional outline (cross-sectional outline) of a conventional steel kilim. Further progress has been made in reducing the amount of material used for the Pil and VIr rims, as well as the weight of the rims. Unlike steam-made rims, they do not use plate material with uniform thickness, so the hollow part is Since the surrounding wall thickness can be made uneven according to the required SK, it is also possible to make the part where one strength is required thicker than the other parts, and there is an advantage that the strength paranos of the rim cross section can be set arbitrarily.

(Embodiment) An embodiment of j'l will be described based on the drawings shown in FIGS. 1 to 6.

In this example, similar to the steel WO type rim made by Lt. America, the rim has a cross section in which the ears ill and fi+ are hollow parts (11), and the starting materials are shown in Figure 1. ■ As a material, knead it and form it into the shape shown in Fig. 3 by knead and roll forming.

In the cross section of the profile of the starting material 1, the abdominal capital (
2), step part (3) that becomes the receiver pressure contact part, and further KVi
The shape between the stepped portions 131 and 131 is determined by the final finished dimension KR at the time of extrusion molding.

On the other hand, in the ear part (1) outside the step part (31 and abdomen (2)), the gap between the opposing inner walls of the hollow part (I] is set larger than the finished dimension, and the rising edge The angle is set to be small (the angle between the abdomen (2) and the ears (1) is large).

The starting material with this cross section is roll-formed in multiple steps, and in this example, six steps are performed.In each roll, the ears il+ and +11 are pressed inward from the outside (to form the ears). It is processed so that it gradually rises.

The above-mentioned rolling process is illustrated as follows: from a bed as shown in FIG. 1, through a plurality of steps, to an intermediate step as shown in FIG. 2, and further through a plurality of steps to a finished state (FIG. 3). In this processing process, no abnormal deformation stress is applied to the meat F1 that forms the ear part m, and only bending force acts on this thick part, resulting in the final finish! It is molded into 7 shapes.

Therefore, there is no fear that wrinkles will occur in the cross section of the mold material during this roll forming process.

In this embodiment, points (A1 at both ends of the abdomen (21), point (B) at the tip of the stepped portion (3), and +C at the outer end of the tip arc-shaped portion
The J point portion becomes the bending portion, and the roll shape in each step is set to a predetermined shape so that these portions are bent and deformed to a predetermined degree.

The molded material formed into a predetermined finished cross section through the above steps is bent into an annular shape as shown in FIG. 4, and then the joined ends are joined by appropriate means as shown in FIG. 5 to complete the rim.

Alternatively, the cross-section of the starting material may have an external shape as shown in FIG. In this case, either the portion corresponding to the curved part such as the ear (1) in the cross section of the finished product is set to an angular shape, or if this corner is press-formed to the curve of the cross-sectional shape of the finished product at the time of roll forming. In this case, there is an advantage that the cross-sectional shape of the die for extrusion 6y and carving can be simplified.

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory diagrams showing changes in the cross section of the mold material when the method of the embodiment of the present invention is adopted, and FIG. FIG. 5 is an explanatory view of the process of forming this into a rim, FIG. 6 is an explanatory view showing another cross section of the mold material as a starting material, and FIG. 7 is a cross-sectional view of a conventional steel rim. Figure 8 is an explanatory view of the cross section of the rim when this is made into one piece using extrusion molding material as it is, and in the figure (1)...
...Ear part (Il+...Hollow part (2)
...Abdomen (3) ...Danbe's agent Patent attorney Yoshihiro Sakaue 〒94 O41Z1O1 Figure 2 Abdominal rest

Claims (1)

[Claims] In a method of manufacturing a rim with a hollow cross section by using an extrusion molding material as a starting material and bending it, the dimensions of part or all of the hollow part of the cross section of the extrusion molding material are set in advance to be larger than the finished dimension, A method for producing a hollow cross-section rim, in which the extrusion molding material is pressurized and deformed by roll forming to reduce part or all of the hollow portion to the finished size.