JP3593381B2 - Pipe flattening method and die used for it - Google Patents
Pipe flattening method and die used for it Download PDFInfo
- Publication number
- JP3593381B2 JP3593381B2 JP08788695A JP8788695A JP3593381B2 JP 3593381 B2 JP3593381 B2 JP 3593381B2 JP 08788695 A JP08788695 A JP 08788695A JP 8788695 A JP8788695 A JP 8788695A JP 3593381 B2 JP3593381 B2 JP 3593381B2
- Authority
- JP
- Japan
- Prior art keywords
- pipe
- mold
- flattening
- curvature
- shape
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- 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.)
- Expired - Lifetime
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Description
【0001】
【産業上の利用分野】
本発明は、円形断面のパイプ(鋼管)から断面が卵状あるいはトラック状のような偏平断面のパイプを製作するための偏平加工法とそれに用いる金型に関する。
【0002】
【従来の技術】
自動車部品の排気系に用いられるパイプにおいては、軽量、高剛性、コストダウンを目的として、従来板金を金型で成形し、それを合わせて最中(もなか)形状にして、その合わせ部を溶接して扁平な形状のパイプを製作していた。
【0003】
【発明が解決しようとする課題】
パイプはその径が大きいほど剛性が高くなるため、極力径を大きくする傾向にある。車体内で干渉物があるとパイプを曲げ、曲げだけで干渉を避けられない場合はパイプを潰(つぶ)して対応する。潰し代が小さい場合は問題ないが、従来のほぼ平坦な潰し部のある金型を用いて、大きく一部が平面状になるように潰した場合は、平面を形成すべき部分が凹んで瓢箪形になってしまう結果となる。
【0004】
本発明はこのような従来のパイプの偏平加工における難点を、円形断面かそれに近い鋼管を用い、直接プレス加工を行うことによって解決しようとするものである。
【0005】
【課題を解決するための手段】
本発明は真円かそれに近い円形断面のパイプから偏平な断面パイプへと加工する偏平加工において、金型のパイプ潰し部の形状を円弧形状とし、その曲率(1/R)を下記(I)式とした金型を用いて押圧加工することを特徴とするパイプの偏平加工法である。
但し、tは肉厚(mm),R0は円形断面パイプの外半径(mm)である。
【0006】
また、本発明のパイプ偏平加工用金型はパイプ潰し部の形状が上記(I)式を満足する曲率を有する。
【0007】
即ち、曲率(1/R)がパイプの肉厚tと外径R0に対して、
であると、パイプの一部が座屈して内面側に凸になり、所定の形状および剛性が得られない。
一方、曲率が、
であると、パイプが充分に潰されず、他の部品のスペースを充分に確保することができない。ここで、パイプの剛性は肉厚が大きいほど大きく、外径が大きいほど偏平しやすい。従って、パイプの肉厚と外径に応じて、最適な金型曲率を選択する必要がある。
【0008】
さらに、パイプを安定して偏平加工するためには、曲率はより好ましくは下記を満足することが好ましい。
【0009】
本発明において、鋼管を偏平加工するに際しては、プレス油、パイプの潤滑処理等を適用すると、さらに優れた偏平形状を安定して得ることが可能であり、生産性を考慮して適宜選択することができるが、いずれも本願発明の対象とするところである。
【0010】
【作用】
金型のパイプ潰し部の形状を前記曲率を有した構造としたことにより、パイプの中へ中子をいれなくても押圧(プレス)によって、パイプの所定必要部分を凹ませることなくほぼ平面に近い状態に潰すことが可能となる。これによって板金の最中合わせによらなくとも、円形断面かそれに近い鋼管を用いて直接プレス加工で扁平なパイプを製作できる。
【0011】
【実施例】
図1は本実施例で用いた金型の形状を示す図であり、偏平加工部の曲率を(a)〜(d)のごとく、次第に変化させた金型を用いた。図2(a)は本発明の金型1a,1bを用いてプレスしたときの断面図であり、図2(b)は偏平加工後のパイプ表面の曲率を測定する要領を示す図である。
【0012】
これらの金型を用いて、図2に示す要領で電縫鋼管3をプレス加工した。ここで3aは電縫溶接部である。電縫鋼管の外径は70.0mmとし、肉厚は2.6および4.0mmとした。金型の曲率は表1に示す5種類とした。
【0013】
【表1】
【0014】
上記の電縫鋼管と金型を用いて、プレス加工した結果を表2に示す。表2のプレス結果において、●は偏平部の形状がほぼ直線に近く、結果が良好であったことを示し、○は結果が比較的良好であったことを示す。×はパイプが周方向に座屈したか、偏平後の形状が不充分であって、いずれも偏平加工が不良であったことを示す。
【0015】
【表2】
【0016】
表2から明らかなように、金型の曲率が本発明条件を満足するNo.3,4,8,9では満足すべき偏平結果が得られている。図3(a)にはNo.3を例として、偏平加工後のパイプ4の断面形状を示す。これに対して、金型の曲率が小さすぎたNo.1,2,6,7ではパイプの一部が重度あるいは軽度に周方向に座屈しており、金型の曲率が大きすぎたNo.10では偏平が不足していて目的とする形状が得られておらず、いずれも本発明の目的を満足していない。図3(b)には不良の場合の例として、No.1の偏平加工後の断面形状を示す。鋼管が周方向に座屈していることがわかる。
【0017】
【発明の効果】
本発明によれば、パイプに中子を入れなくても偏平断面を有するパイプを加工することが可能であり、安価かつ短工程で偏平加工することを可能としたものであり、かつ中子を使わないことから曲がり管の一部を偏平加工することも容易とした。これらは産業の発展に寄与するところ大である。
【図面の簡単な説明】
【図1】金型の形状を示す図である。
【図2】(a)は本発明の金型を用いたプレス時の断面図である。(b)はパイプ表面の曲率測定時の様子を示す図である。
【図3】(a)は表2中No.3のパイプのプレス加工後の端面図であり、(b)はNo.1のパイプのプレス加工後の端面図である。
【符号の説明】
1a 上型
1b 下型
3 電縫パイプ
4 プレス加工後のパイプ[0001]
[Industrial applications]
The present invention relates to a flattening method for manufacturing a pipe having a flat cross section such as an oval or a track from a pipe (steel pipe) having a circular cross section, and a mold used therefor.
[0002]
[Prior art]
For pipes used in the exhaust system of automobile parts, in order to reduce weight, increase rigidity, and reduce costs, conventional sheet metal is molded using a metal mold, and the metal sheet is formed into a middle shape and the joint is welded. To produce a flat pipe.
[0003]
[Problems to be solved by the invention]
Since the rigidity of a pipe increases as its diameter increases, the diameter tends to be as large as possible. If there is an obstacle in the vehicle body, the pipe is bent. If the interference cannot be avoided only by bending, the pipe is crushed. There is no problem when the crushing margin is small, but when using a conventional mold with a substantially flat crushed part and crushing so that a large part becomes flat, the part that should form the plane is concave and the gourd The result is that it takes shape.
[0004]
The present invention is intended to solve such a difficulty in flattening of a conventional pipe by directly pressing a steel pipe having a circular cross section or a steel pipe having a circular cross section.
[0005]
[Means for Solving the Problems]
According to the present invention, in flattening processing for processing a pipe having a circular cross-section close to a perfect circle into a flat cross-section pipe, the shape of the crushed pipe portion of the mold is an arc shape, and its curvature (1 / R) is defined by the following (I). This is a flattening method for a pipe, characterized in that pressing is performed using a mold having a formula.
Here, t is the wall thickness (mm), and R0 is the outer radius (mm) of the circular pipe.
[0006]
Further, in the mold for flattening a pipe of the present invention, the shape of the crushed portion of the pipe has a curvature satisfying the above formula (I).
[0007]
That is, the curvature (1 / R) is determined by the thickness t of the pipe and the outer diameter R0 .
In this case, a part of the pipe buckles and becomes convex on the inner surface side, and a predetermined shape and rigidity cannot be obtained.
On the other hand, the curvature is
In this case, the pipe is not sufficiently crushed, and a space for other parts cannot be sufficiently secured. Here, the rigidity of the pipe increases as the wall thickness increases, and the pipe tends to flatten as the outer diameter increases. Therefore, it is necessary to select an optimum mold curvature according to the wall thickness and the outer diameter of the pipe.
[0008]
Furthermore, in order to stably flatten the pipe, the curvature more preferably satisfies the following.
[0009]
In the present invention, when flattening a steel pipe, it is possible to obtain a more excellent flat shape stably by applying a press oil, lubrication treatment of the pipe, etc., and appropriately select it in consideration of productivity. However, all of them are objects of the present invention.
[0010]
[Action]
By making the shape of the crushed portion of the mold into a structure having the above-described curvature, even if the core is not inserted into the pipe, the pipe is pressed (pressed) into a substantially flat surface without depressing a predetermined necessary portion of the pipe. It becomes possible to crush it in a close state. Thus, a flat pipe can be manufactured by direct press working using a steel pipe having a circular cross section or a steel pipe having a circular cross section, without using the middle of sheet metal.
[0011]
【Example】
FIG. 1 is a view showing the shape of the mold used in the present embodiment. A mold in which the curvature of the flattened portion is gradually changed as shown in FIGS. FIG. 2A is a cross-sectional view when the molds 1a and 1b of the present invention are pressed, and FIG. 2B is a view showing a procedure for measuring the curvature of the pipe surface after flattening.
[0012]
Using these dies, the
[0013]
[Table 1]
[0014]
Table 2 shows the results of press working using the above-described ERW steel pipe and mold. In the press results in Table 2, the open circles indicate that the flat portion was almost linear and the results were good, and the open circles indicate that the results were relatively good. × indicates that the pipe buckled in the circumferential direction or the shape after flattening was insufficient, and that the flattening process was poor in each case.
[0015]
[Table 2]
[0016]
As is clear from Table 2, the curvature of the mold satisfies the conditions of the present invention. In 3, 4, 8, and 9, satisfactory flattening results were obtained. FIG. 3 shows an example of a cross-sectional shape of the pipe 4 after flattening. On the other hand, No. 3 where the curvature of the mold was too small. In Nos. 1, 2, 6, and 7, a part of the pipe was severely or slightly buckled in the circumferential direction, and the curvature of the mold was too large. In No. 10, the flatness was insufficient and the desired shape was not obtained, and none of them satisfied the object of the present invention. FIG. 3B shows No. 3 as an example of a failure. 1 shows a cross-sectional shape after flattening. It can be seen that the steel pipe is buckling in the circumferential direction.
[0017]
【The invention's effect】
According to the present invention, it is possible to process a pipe having a flat cross section without inserting a core into the pipe, and it is possible to perform flat processing at a low cost and in a short process. Because it is not used, it is easy to flatten a part of the bent pipe. These are the major contributors to industrial development.
[Brief description of the drawings]
FIG. 1 is a view showing the shape of a mold.
FIG. 2A is a cross-sectional view at the time of pressing using the mold of the present invention. (B) is a figure which shows a mode at the time of the curvature measurement of the pipe surface.
FIG. 3 (a) shows No. 2 in Table 2. 3B is an end view of the pipe after press working, and FIG. FIG. 2 is an end view of the pipe 1 after press working.
[Explanation of symbols]
1a Upper die 1b Lower die 3 ERW pipe 4 Pipe after pressing
Claims (2)
但し、tは肉厚(mm),R0は円形断面パイプの外半径(mm)In flattening a pipe from a substantially circular cross-section pipe to a flat cross-section pipe, the shape of the crushed pipe portion is an arc shape having a radius R, and the curvature (1 / R) is a mold having the following formula (I). A flattening method for a pipe, characterized in that a predetermined required portion of the pipe is crushed into a substantially flat state without being depressed by pressing using a pipe .
Here, t is the thickness (mm), and R 0 is the outer radius (mm) of the circular pipe.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP08788695A JP3593381B2 (en) | 1995-04-13 | 1995-04-13 | Pipe flattening method and die used for it |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP08788695A JP3593381B2 (en) | 1995-04-13 | 1995-04-13 | Pipe flattening method and die used for it |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH08281334A JPH08281334A (en) | 1996-10-29 |
JP3593381B2 true JP3593381B2 (en) | 2004-11-24 |
Family
ID=13927364
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Application Number | Title | Priority Date | Filing Date |
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JP08788695A Expired - Lifetime JP3593381B2 (en) | 1995-04-13 | 1995-04-13 | Pipe flattening method and die used for it |
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Country | Link |
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JP (1) | JP3593381B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8087277B2 (en) | 2005-10-28 | 2012-01-03 | Toyota Jidosha Kabushiki Kaisha | Method for correcting metal tube and corrective press die |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6016841B2 (en) * | 2014-03-31 | 2016-10-26 | 本田技研工業株式会社 | Manufacturing method of body frame |
-
1995
- 1995-04-13 JP JP08788695A patent/JP3593381B2/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8087277B2 (en) | 2005-10-28 | 2012-01-03 | Toyota Jidosha Kabushiki Kaisha | Method for correcting metal tube and corrective press die |
Also Published As
Publication number | Publication date |
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JPH08281334A (en) | 1996-10-29 |
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