JPS6372442A - Manufacture of rim stock for automobile - Google Patents
Manufacture of rim stock for automobileInfo
- Publication number
- JPS6372442A JPS6372442A JP21589086A JP21589086A JPS6372442A JP S6372442 A JPS6372442 A JP S6372442A JP 21589086 A JP21589086 A JP 21589086A JP 21589086 A JP21589086 A JP 21589086A JP S6372442 A JPS6372442 A JP S6372442A
- Authority
- JP
- Japan
- Prior art keywords
- rim
- blank
- thickness
- rotary roll
- roll forming
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 238000000034 method Methods 0.000 claims abstract description 19
- 238000005096 rolling process Methods 0.000 claims abstract description 14
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 6
- 238000005452 bending Methods 0.000 claims abstract description 6
- 239000010959 steel Substances 0.000 claims abstract description 6
- 238000003466 welding Methods 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims description 60
- 238000005520 cutting process Methods 0.000 abstract description 2
- 230000008719 thickening Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 7
- 230000001788 irregular Effects 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000011324 bead Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
- B21H1/00—Making articles shaped as bodies of revolution
- B21H1/06—Making articles shaped as bodies of revolution rings of restricted axial length
- B21H1/12—Making articles shaped as bodies of revolution rings of restricted axial length rings for ball or roller bearings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
- B21H1/00—Making articles shaped as bodies of revolution
- B21H1/06—Making articles shaped as bodies of revolution rings of restricted axial length
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Bending Of Plates, Rods, And Pipes (AREA)
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
この発明は、自動車の車輪を構成するリム材の製造方法
に関するものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method of manufacturing a rim material constituting a wheel of an automobile.
〈従来技術とその問題点〉
従来、十分な強度と成形精度が要求される自動車用のリ
ム材の製造に際しては、−ａに第４図に示されるような
工程が採用されている。<Prior Art and its Problems> Conventionally, in the production of automobile rim materials that require sufficient strength and molding precision, a process as shown in FIG. 4 has been adopted in -a.
即ち、まずアンコイラ−にかけて巻き戻された熱延スリ
ットコイルをシャーにより適当な長さに切断し、鼻曲げ
加工を施してからフラッシュバット溶接により肉厚が一
定の環状素材となす。次いで溶接部のトリミングを行い
、冷却した後、これを第５図に例示するような回転ロー
ル成形機にかけ（第５図において符号１，１′は成形ロ
ールであり、２は“成形途中の環状素材を示す）、第６
図に例示する如き多段工程（第６図は各段階における素
材幅方向の断面図であり、複数台の回転ロール成形機に
て第６図の矢印方向へ順次成形度合を大きくして行くが
、通常３〜５の工程数がとられる）を経て最終のリム断
面形状に成形加工され、更にエキスバンドにより真円矯
正がなされる。この後、得られたリム材は別途成形され
たディスクと接合され、ホイールとして組立てられる。That is, first, a hot-rolled slit coil that has been rewound by an uncoiler is cut into a suitable length by a shear, subjected to a nose bending process, and then flash butt welded to form an annular material having a constant wall thickness. Next, the welded part is trimmed, cooled, and then applied to a rotary roll forming machine as shown in Fig. 5 (in Fig. 5, numerals 1 and 1' are forming rolls, and 2 is an annular shape in the middle of forming. ), 6th
A multi-stage process as exemplified in the figure (Figure 6 is a sectional view in the width direction of the material at each stage, and the degree of forming is gradually increased in the direction of the arrow in Figure 6 using multiple rotary roll forming machines, The rim is shaped into the final rim cross-sectional shape through 3 to 5 steps (usually 3 to 5 steps are required), and then rounded using an expanding band. The resulting rim material is then joined to a separately molded disc and assembled into a wheel.
ところが、上記工程における「回転ロール成形の段階」
での環状素材に加わる歪は相当に大きなものであり、こ
のため形成されるリム材の幅方向肉厚に第７図に例示す
るような偏差が生じるのを如何ともし難かった。ここで
、第７図はリム材の幅方向位置に相応する肉厚を表した
グラフであり（肉厚値は白丸で示す）、図中のハンチン
グ付与図形はリム材の幅方向断面の模式図である。However, the "rotary roll forming stage" in the above process
The strain applied to the annular material is quite large, and it is therefore difficult to do anything to prevent deviations in the thickness of the formed rim material in the width direction, as illustrated in FIG. Here, Fig. 7 is a graph showing the wall thickness corresponding to the position in the width direction of the rim material (thickness values are indicated by white circles), and the hunting figure in the figure is a schematic diagram of the cross section of the rim material in the width direction. It is.
つまり、環状フラット素材から回転ロール成形によって
自動車用リム材を製造する場合、第７図に示す如くに幅
端部が減肉すると言う現象を避は得なかったのである。In other words, when manufacturing an automobile rim material from an annular flat material by rotary roll forming, the phenomenon of thinning at the width end portion as shown in FIG. 7 is unavoidable.
そのため、自動車用リム材の製造に当たっては前記肉厚
減少を補償する素材厚設計が行われており、従ってその
分だけリムとしては余分な重量増加を余儀無くされてい
たのみか、材料過使用と言う経済的な不利をも甘受して
いた。For this reason, when manufacturing automobile rim materials, the material thickness is designed to compensate for the decrease in wall thickness, and this results in an increase in the weight of the rim, or overuse of material. They also accepted the economic disadvantages mentioned above.
〈問題点を解決するための手段〉
この発明は、上述のような観点から、格別な製造能率低
下を伴うことのない、肉厚が均等な自動車用リム材の量
産手段を提供し、素材の節約とホイールの軽量化を図る
べく行われた本発明者等の研究によって完成されたもの
であり、
鋼板を環状に曲げ、突合わせ端部を溶接して環状リム素
材とした後、これにリング圧延を施して素材幅方向の中
央部よりも両エツジ部付近の肉厚を厚くし、次いで回転
ロール成形によりリム形状に仕上げることによって、肉
厚偏差が極めて少なく、軽量でしかも十分な強度を備え
た自動車用リム材を能率良く製造し得るようにした点、
に特徴を有するものである。<Means for Solving the Problems> From the above-mentioned viewpoints, the present invention provides a means for mass-producing automobile rim materials with uniform wall thickness without any particular reduction in manufacturing efficiency, and improves the quality of the material. This was completed through research conducted by the inventors to save money and reduce the weight of the wheel. After bending a steel plate into an annular shape and welding the butt ends to create an annular rim material, a ring was attached to this material. By applying rolling to make the wall thickness thicker near both edges than at the center in the width direction of the material, and then finishing it into a rim shape by rotating roll forming, it has extremely little wall thickness deviation, is lightweight, and has sufficient strength. The invention enables efficient production of automotive rim materials,
It has the following characteristics.
第１図は、この発明の自動車用リム材の製造工程例を説
明した概略模式図である。FIG. 1 is a schematic diagram illustrating an example of the manufacturing process of an automobile rim material according to the present invention.
第１図において、まず、例えば熱延スリットコイルを所
定長さに切断する等の手段により得られたフラット鋼板
３ （第１図（ａ））は環状に曲げ加工（鼻曲げ加工）
され、その当接端部が溶接されて環状リム素材４（第１
図（ｂ）） とされる。なお、第１図（ｂ）における符
号５は溶接部を示す。In FIG. 1, first, a flat steel plate 3 (FIG. 1(a)) obtained by, for example, cutting a hot-rolled slit coil into a predetermined length is bent into an annular shape (nose bending).
The contact end is welded to form an annular rim material 4 (first
Figure (b)). Note that the reference numeral 5 in FIG. 1(b) indicates a welded portion.
次いで、上記環状リム素材４にはリング圧延が施され（
第１図（Ｃ１）、回転ロール成形によって減肉する素材
幅方向側エツジ部付近の肉厚が中央部のそれよりも厚い
異形断面に成形される。つまり、次工程である回転ロー
ル成形の際に減肉する部分を、予め増肉させておく訳で
ある。増肉する割合は、素材や製品の肉厚或いは製品形
状等によっても多少異なるが、好ましくは１０〜３０％
程度である。Next, the annular rim material 4 is subjected to ring rolling (
In FIG. 1 (C1), the material is formed into an irregular cross-section in which the wall thickness near the edge portion in the width direction of the material is thicker than that in the center portion, where the thickness is reduced by rotary roll forming. In other words, the thickness of the parts that will be reduced during the next process of rotary roll forming is increased in advance. The rate of increase in thickness varies somewhat depending on the material, product thickness, product shape, etc., but is preferably 10 to 30%.
That's about it.
なお、第２図ｆａ）乃至第２図（ｄ）はリング圧延によ
って成形される環状素材の断面形状例であるが、特にこ
れらの形状に限定されるものではない。そして、このリ
ング圧延は、前記第５図で示したような回転ロール成形
機を利用して実施することができるが、第３図に例示す
る如きリングローリングマシーンを使用すればより良好
な作業性が確保される。In addition, although FIG. 2fa) to FIG. 2(d) are examples of the cross-sectional shape of the annular material formed by ring rolling, the shape is not particularly limited to these shapes. This ring rolling can be carried out using a rotary roll forming machine as shown in FIG. is ensured.
また、前記第１図（Ｃ１における符号６，６′は圧延ロ
ールを、そして７，７′は側面圧下ロールを示しており
、第３図における符号８はガイドロールを示している。Further, reference numerals 6 and 6' in FIG. 1 (C1) indicate rolling rolls, 7 and 7' indicate side reduction rolls, and reference numeral 8 in FIG. 3 indicates a guide roll.
続いて、リング圧延された環状リム素材４には従来通り
の回転ロール成形が施され（第１図（ｄ））、リム形状
に成形される。Subsequently, the ring-rolled annular rim material 4 is subjected to conventional rotary roll forming (FIG. 1(d)) to form a rim shape.
このような本発明の方法によると回転ロール成形による
最減肉部の肉厚が安定して確保されるので、リム材の平
均肉厚を小さくでき、その分だけ素材の節約とホイール
の軽量化を達成することができる。そして、以上の説明
からも明らかなように、この発明の方法は所謂“自動車
のリム材”の製造のみに限らず、回転ロール成形される
ことにより幅方向の厚み偏差を生じる他の類似製品に適
用しても同様の効果が得られるものであり、ここで言う
ところの「自動車のリム材Ｊとはこれら類似品をも含め
て意味するものであることを理解すべきである。According to the method of the present invention, the wall thickness of the part with the least thickness reduction due to rotary roll forming is stably ensured, so the average wall thickness of the rim material can be reduced, and the material can be saved accordingly and the weight of the wheel can be reduced. can be achieved. As is clear from the above explanation, the method of the present invention is not limited to the production of so-called "automobile rim materials", but can also be applied to other similar products that have thickness deviations in the width direction due to rotary roll forming. Similar effects can be obtained by applying the same, and it should be understood that the term ``automobile rim material J'' here includes these similar products.
ところで、前記第２図で示す如き異形断面形状を熱延コ
イルの段階で作成したり、スリットした熱延コイルに加
工を施し異形断面コイルとなしてから第４図で示す工程
でリム材を製造する別法も考えられるが、これらの方法
は圧延歩留が大幅に悪化したり異形断面材のフラッシュ
バット溶接やビード取りが困難であるなど技術的に多（
の問題を抱えていて、工業的に決して好ましい手段とは
言えない。By the way, the irregular cross-sectional shape as shown in FIG. 2 is created at the hot-rolled coil stage, or the slit hot-rolled coil is processed to form an irregular cross-sectional coil, and then the rim material is manufactured in the process shown in FIG. 4. Alternative methods can be considered, but these methods have many technical problems, such as significantly lower rolling yields and difficulties in flash butt welding and bead removal of irregular cross-section materials.
However, it cannot be said to be a desirable method from an industrial perspective.
次いで、この発明を実施例により比較例と対比しながら
具体的に説明する。Next, the present invention will be specifically explained using examples and comparing with comparative examples.
〈実施例〉
まず、厚さが３ｎで、幅が１８０１ｍの熱延スリットコ
イルを１２００１１の長さに切断し、これを用いて第４
図に示す従来注進りにリム材を製造した。<Example> First, a hot-rolled slit coil with a thickness of 3n and a width of 1801m was cut into a length of 120011m, and this was used to
The rim material was manufactured using the conventional method shown in the figure.
一方、厚さが３．１ｆｌで、幅が１６２ｍの熱延スリッ
トコイルを１２００ｍの長さに切断し、これを第１図（
ｂ）の如き環状に曲げてフラッシュバット溶接した後、
これを素材とし本発明の方法に従ってリム材を製造した
。On the other hand, a hot-rolled slit coil with a thickness of 3.1 fl and a width of 162 m was cut into a length of 1200 m, and this was shown in Figure 1 (
After bending into an annular shape as in b) and flash butt welding,
Using this as a raw material, a rim material was manufactured according to the method of the present invention.
即ち、本発明例では、第５図に示す従来の回転ロール成
形機に第１図（Ｃ１Ｏものと類似の圧延ロールを組み込
み、これに上記環状リム素材をセットすると共に、圧延
ロールを回転しながら徐々に該ロール間隔を締め込んで
第２図（Ｃ）に示す異形断面材にリング圧延しく得られ
た圧延材は、リング幅が１８０ｎと拡がり、肉厚は幅中
央部で２．６ｍｍ厚、両端部で３．０ｍｍ厚であった）
、次にこの圧延リングを素材とし従来通りのロール成形
工程にてリム材に仕上げた。That is, in the example of the present invention, a rolling roll similar to the one shown in FIG. 1 (C1O) is incorporated into the conventional rotary roll forming machine shown in FIG. The rolled material was ring-rolled into the irregular cross-sectional material shown in FIG. 2(C) by gradually tightening the distance between the rolls, and the resulting rolled material had a ring width of 180 nm and a wall thickness of 2.6 mm at the center of the width. It was 3.0mm thick at both ends)
Next, this rolled ring was used as a raw material and finished into a rim material using a conventional roll forming process.
このような本発明例と従来例とによって得られた各リム
材について座屈強度や疲労強度等を比較したところ、本
発明例で得られたリム材は全体の肉厚が薄くなっている
（２．６ｍｍ）にも係わらず、リング圧延で材料強度が
高くなると共に成形品の肉厚分布が均一化されているこ
ともあって、座屈強度及び疲労強度とも従来材と大差が
なかった。When comparing the buckling strength, fatigue strength, etc. of each rim material obtained by the example of the present invention and the conventional example, it was found that the rim material obtained by the example of the present invention has a thinner overall wall thickness ( 2.6 mm), there was no significant difference in buckling strength and fatigue strength from the conventional material, partly because the material strength was increased by ring rolling and the thickness distribution of the molded product was made more uniform.
そして、このときの重量比は
３ Ｘ １８０
であり、本発明例で得られたリム材は従来材に比して７
％の軽量化が達成されると共に、７％の素材節減がなさ
れたことは言うまでもない。The weight ratio at this time was 3 x 180, and the rim material obtained in the example of the present invention had a weight ratio of 7 x 180 compared to the conventional material.
Needless to say, a weight reduction of 1.9% was achieved and a material saving of 7% was achieved.
なお、各種テストの結果、本発明の方法を実施する際に
第１図（Ｃ）に示すような［リム側面を圧下成形するロ
ール７．７”Ｊを設けてリング圧延を行い側面形状を調
える方が、座屈に対して有利な製品が得られることも確
認できた。As a result of various tests, it was found that when carrying out the method of the present invention, as shown in FIG. It was also confirmed that a product with better resistance to buckling could be obtained.
以上に説明した如く、この発明によれば、余分な肉厚増
加や重量増加がなく、しかも十分な強度を有するリム材
を高能率で量産することができ、ホイールの軽量化や材
料の節減を簡単・容易に実現することが可能となるなど
、産業上極めて存用な効果がもたらされるのである。As explained above, according to the present invention, it is possible to mass-produce rim materials with sufficient strength without excessive increase in wall thickness or weight, and to reduce the weight of wheels and save materials. It can be realized simply and easily, and it brings about extremely useful effects in industry.
第１図は、本発明に係る一連の自動車用リム材製造工程
例を説明した概略模式図であり、第１図（ａｌ、第１図
（ｂｌ、第１図（Ｃ１及び第１図（ｄｌはその各工程を
模式図化したもの、
第２図は、リング圧延したリム素材の断面形状例、
第３図は、本発明に適用できるリングローリングマシン
の概略斜視図、
第４図は、従来のリム材製造工程を示す工程図、第５図
は、回転ロール成形機でリム材を成形している状態を示
す概略模式図、
第６図は、回転ロール成形機によるリム材の成形段階を
、素材の断面形状で示した工程図、第７図は、従来の方
法で製造されたリム材の幅方向位置による肉厚偏差を示
したグラフである。
図面において、
１．１′・・・成形ロール、
２・・・成形途中の環状素材、
３・・・フラット鋼板、 ４・・・環状リム素材、５
・・・溶接部、 ６，６゛・・・圧延ロール、７
．７′・・・側面圧下ロール、
８・・・ガイドロール。FIG. 1 is a schematic diagram illustrating a series of manufacturing process examples of automobile rim materials according to the present invention, and includes FIGS. 2 is a schematic diagram of each process, FIG. 2 is an example of the cross-sectional shape of a ring-rolled rim material, FIG. 3 is a schematic perspective view of a ring rolling machine that can be applied to the present invention, and FIG. 4 is a conventional Fig. 5 is a schematic diagram showing the state in which the rim material is formed by a rotary roll forming machine, and Fig. 6 is a process diagram showing the rim material manufacturing process by the rotary roll forming machine. , a process diagram showing the cross-sectional shape of the material, and FIG. 7 is a graph showing the wall thickness deviation depending on the position in the width direction of the rim material manufactured by the conventional method. In the drawing, 1.1'... Forming roll, 2... Annular material in the middle of forming, 3... Flat steel plate, 4... Annular rim material, 5
...Welded part, 6,6゛...Roll roll, 7
．． 7'... Side pressure roll, 8... Guide roll.
Claims (1)
材とした後、これにリング圧延を施して素材幅方向の中
央部よりも両エッジ部付近の肉厚を厚くし、次いで回転
ロール成形によりリム形状に仕上げることを特徴とする
、自動車用リム材の製造方法。After bending a steel plate into an annular shape and welding the butt ends to make an annular rim material, it is subjected to ring rolling to make the thickness near both edges thicker than the center in the width direction of the material, and then rolled into a rotating roll. A method for manufacturing an automobile rim material, which is characterized by forming a rim into a rim shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21589086A JPS6372442A (en) | 1986-09-16 | 1986-09-16 | Manufacture of rim stock for automobile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21589086A JPS6372442A (en) | 1986-09-16 | 1986-09-16 | Manufacture of rim stock for automobile |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6372442A true JPS6372442A (en) | 1988-04-02 |
Family
ID=16679954
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21589086A Pending JPS6372442A (en) | 1986-09-16 | 1986-09-16 | Manufacture of rim stock for automobile |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6372442A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100396433C (en) * | 2005-07-22 | 2008-06-25 | 武汉理工大学 | Grooved ball section annular-piece cold-ring-rolling shaping method |
| CN102218490A (en) * | 2010-12-22 | 2011-10-19 | 珍晟T.E.C株式会社 | Method for manufacturing of caterpillar idler rim and mould device |
| CN109396305A (en) * | 2018-12-27 | 2019-03-01 | 山东瑞烨法兰有限公司 | A kind of hubbed flange vertical ring rolling machine processing grinding tool |
| TWI757961B (en) * | 2020-11-09 | 2022-03-11 | 惠亞工程股份有限公司 | Macufacturing method for waffle barrel and shaping device |
-
1986
- 1986-09-16 JP JP21589086A patent/JPS6372442A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100396433C (en) * | 2005-07-22 | 2008-06-25 | 武汉理工大学 | Grooved ball section annular-piece cold-ring-rolling shaping method |
| CN102218490A (en) * | 2010-12-22 | 2011-10-19 | 珍晟T.E.C株式会社 | Method for manufacturing of caterpillar idler rim and mould device |
| CN109396305A (en) * | 2018-12-27 | 2019-03-01 | 山东瑞烨法兰有限公司 | A kind of hubbed flange vertical ring rolling machine processing grinding tool |
| TWI757961B (en) * | 2020-11-09 | 2022-03-11 | 惠亞工程股份有限公司 | Macufacturing method for waffle barrel and shaping device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4185370A (en) | Method of making a wheel rim | |
| US20020003373A1 (en) | Method of manufacturing cold formed light alloy automotive wheel rim | |
| US4266417A (en) | Steel flanged wheel rims for motorized bicycles or two-wheeled vehicles and a process for producing the rims | |
| US6719375B2 (en) | Wheel rim and wheel rim manufacturing method | |
| WO1995011768A1 (en) | Method for producing a rim for a vehicle wheel | |
| JP4053437B2 (en) | Manufacturing method of unequal thickness rim | |
| US6189357B1 (en) | Apparatus and process for forming vehicle wheel rims | |
| JPS6372442A (en) | Manufacture of rim stock for automobile | |
| US4143533A (en) | Method of manufacturing solid wheel rims | |
| US7251890B2 (en) | Method for producing wheel pans | |
| JPS5915733B2 (en) | Method of manufacturing alloy wheels for vehicles | |
| US4080704A (en) | Circular form process for pulleys | |
| JP3807859B2 (en) | Manufacturing method of disc for automobile wheel | |
| US4127022A (en) | Method of manufacturing solid wheel rims | |
| US20040143968A1 (en) | Method of making rim having opposite hollow flanges | |
| JP2596688B2 (en) | Manufacturing method of light alloy wheel | |
| US6026667A (en) | Apparatus for manufacturing a one end flange-less wheel rim | |
| US5832609A (en) | Method for producing a variable thickness rim for a vehicle wheel | |
| JP2003236637A (en) | Two-piece wheel, and method for manufacturing the same | |
| US1623883A (en) | Method of manufacturing seamless rims and wheel disks | |
| US6584824B1 (en) | Apparatus for producing a vehicle wheel rim | |
| US2170617A (en) | Manufacture of disk wheels | |
| JPH10180387A (en) | Production of rim blank for wheel | |
| JPH02307637A (en) | Manufacture of disk stock in wheel for vehicle | |
| JPH0299401A (en) | Manufacturing method of rim for tubeless tire and its form of material |