JP4511744B2 - Exhaust pipe and method of manufacturing exhaust pipe - Google Patents

Exhaust pipe and method of manufacturing exhaust pipe Download PDF

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JP4511744B2
JP4511744B2 JP2001023074A JP2001023074A JP4511744B2 JP 4511744 B2 JP4511744 B2 JP 4511744B2 JP 2001023074 A JP2001023074 A JP 2001023074A JP 2001023074 A JP2001023074 A JP 2001023074A JP 4511744 B2 JP4511744 B2 JP 4511744B2
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雅也 高村
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Sango Co Ltd
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Description

【０００１】
【発明の属する技術分野】
本発明は排気管および排気管の製造方法に関する。
【０００２】
【従来の技術】
従来、内燃機関用の排気管として、遮音性の向上や排気ガスを保温して触媒浄化性能を向上させる目的から、図８に示すように、内管１０１と、その外周に空間１０２を設けて配設した外管１０３とからなる二重管が採用されている。
【０００３】
このような二重管は、その両端部において相互に連結されるが、その内管１０１と外管１０３との熱膨脹差による相対移動を可能にするために、内外管１０１，１０３の他端側Ｂを相互にスポット溶接などで固着し、一端側Ａを、内管１０１と外管１０３との間に編組したステンレス細線をリング状にプレス成形した保持部材（スペーサ）１０４を摺動可能に配置して構成している。
【０００４】
そして、このような保持部材１０４の配置方法としては、図８において、先ず、内管１０１の一端側Ａに外方へ突出する第１膨出部１０５を形成した後、リング状の保持部材１０４を内管１０１の外周部に外嵌し、次で、第２膨出部１０６を形成する方法が、例えば特開平８−４５２４号公報に示されている。
【０００５】
【発明が解決しようとする課題】
前記従来のように、リング状の保持部材１０４を配置するものにおいては、その保持部材１０４の組付け作業を考慮して、保持部材１０４の内径を内管１０１の外径よりも若干大きくするか、或いは保持部材１０４の外径を外管１０３の内径よりも若干小さくして、保持部材１０４と内管１０１または外管１０３との間に隙間（クリアランス）１０７を設ける必要がある。
【０００６】
しかし、前記従来の二重管の製造方法においては、保持部材１０４を挿入した後においても前記の隙間１０７が形成されたまま存在するため、この二重管を内燃機関の排気管として車両に搭載した場合、エンジンの振動により排気管が振動しやすく、その振動により保持部材１０４が内管１０１または外管１０３によって叩かれ、前記の隙間１０７が当初の大きさよりも拡大し、異音が発生するおそれがあった。
【０００７】
そこで本発明は、前記保持部材の組付け作業性の悪化を伴うことなく、前記のような異音の発生を防止できる排気管と排気管の製造方法を提供することを目的とするものである。
【０００８】
【課題を解決するための手段】
前記の課題を解決するために、請求項１記載の第１の発明は、内管と、該内管の外周に空間を設けて配置した外管と、前記空間部の一部に配置されたリング状の保持部材と、該保持部材の前後において内管に形成した凸部を有する排気管であって、前記両凸部間の内管の外径が前記凸部の外側の内管の外径よりも大きく、かつ、前記両凸部の間の内管と前記保持部材とが接触していることを特徴とする排気管である。
【０００９】
請求項２記載の第２の発明は、内管と、該内管の外周に空間を設けて配置した外管と、前記空間部の一部に配置されたリング状の保持部材とを備えた排気管の製造方法であって、
前記内管の外周に前記保持部材を、内管との間に隙間を設けて嵌合した後に、前記保持部材の前後の内管に凸部を設けるとともに、前記保持部材と前記内管とが少なくとも接触するように前記両凸部間の内管を拡径することを特徴とする排気管の製造方法である。
【００１１】
請求項３記載の第３の発明は、前記第２の発明において、前記保持部材が配置された部分における内管の内部に、内管の前記両凸部を形成する突起と、前記両凸部間の内管を拡径する拡径面を形成した型を配置し、該型を径方向の外側へ移動して、前記両凸部の形成と、該両凸部間の拡径を同時に行うようにしたことを特徴とする排気管の製造方法である。
【００１２】
【発明の実施の形態】
図１乃至図７に示す本発明の実施例について説明する。
【００１３】
図１及び図２は第１参考例を示す。
【００１４】
該参考例の製造方法は、先ず、排気管を構成する直管状の金属製の内管１における一端部Ａの外周に、メリヤス状に編組した金属細線をリング状にプレス成形した保持部材２を図１（ａ）に示すように嵌める。
【００１５】
この保持部材２の内径は、図１（ａ）に示すように、内管１の外径よりも若干大きく設定され、内管１と保持部材２との間に所定の隙間（クリアランス）ｔが形成されるようになっている。この隙間ｔの大きさは、保持部材２を内管１に容易に挿入できる程度に設定されるが、内管１の外径および保持部材２の内径のバラツキや組付け作業性を考慮して設定され、通常０．２ｍｍ程度に設定される。
【００１６】
このような隙間ｔを有することにより、保持部材２の内管１に対する組付け作業が容易に行える。
【００１７】
次に、前記保持部材２が挿入配置された近傍の内管１を図１（ｂ）に示すように拡径する。この拡径方法としては、例えば図１（ａ）に示すような、前記内管１の素管より少なくとも前記隙間ｔ分大径の円筒状型面部３ａと、先部に先細状テーパ面３ｂを有する型３を使用し、該型３を図示しない駆動手段により前記内管１の一端部Ａの開口部より圧入し、図１（ｂ）に示すように内管１における前記保持部材２が配置された近傍の一端部Ａを拡径する。１ｄは拡径された拡径部を示す。
【００１８】
前記のように内管１を拡径する方法は、前記参考例の型によるものの他に、周知の拡径方法を採用することができる。
【００１９】
更に、前記内管１の拡径量は、少なくとも前記の隙間ｔがゼロになり、内管１と保持部材２が接触する拡径量にするものであるが、保持部材２が多少圧縮されるように拡径してもよい。
【００２０】
なお、前記の内管１の拡径工程の前後のいずれかにおいて、前記保持部材２と内管１を相互にスポット溶接などで固着して保持部材２の軸方向移動を防止するようにするとよい。
【００２１】
次に、前記の型３を抜いた後、図１（ｃ）に示すように、前記保持部材２の外周に嵌合する径で、かつ、他端部Ｂに前記内管１の外周に嵌合する縮径部４ａを形成した金属製の外管４に、その大径側開口部から前記内管１および保持部２を挿入し、内管１の他端部Ｂ側と外管４の縮径部４ａをスポット溶接などで固着する。なお、外管４は、その肉厚が内管１の肉厚よりも厚いものが使用される。
【００２２】
以上により、図１（ｃ）に示すような、保持部材２の内周面が内管１の拡径部１ｄにおいて接触し、保持部材２の外周面が外管４に接触し、かつ、内管１と外管４との間に空間５を有する二重管からなる排気管が製造される。
【００２３】
図３は第２参考例を示す。
【００２４】
本第２参考例は、先に二重管を構成して、この二重管に、前記第１参考例と同様な内管加工によって保持部材を配置する製造方法を示すものである。
【００２５】
先ず、図３（ａ）に示すような他端部Ｂに縮径部４ａを形成した直管状の金属製の外管４内に、該外管４より薄肉の金属製の内管１を、その他端部Ｂを前記外管４の縮径部４ａに圧入するとともに該部をスポット溶接などで固着して図３（ａ）に示すような内管１と外管４との間に空間５を有する二重管を形成する。
【００２６】
次に、前記空間５の開口部から前記と同様の保持部材２を図３（ｂ）に示すように空間５内へ挿入し、保持部材２を内管１の一端部Ａ側の外周に配置する。このとき、保持部材２と内管１との間には前記のような隙間ｔを有するため、保持部材２の内管１に対する組付け作業が容易に行える。
【００２７】
次に、前記第１参考例と同様の型３により、前記保持部材２が配置された近傍の内管１を図３（ｃ）に示すように前記第１参考例と同様に拡径し、その拡径部１ｄの内管１を保持部材２に接触させる。なお、この内管１の拡径量は、保持部材２が若干圧縮されるようにして、保持部材２の軸方向移動を阻止するようにするとよい。
【００２８】
そして、前記の型３を抜くことにより、前記第１参考例の図１（ｃ）に示すような二重管が製造される。
【００２９】
なお、本第２参考例は、保持部材２の内管側にのみ隙間ｔを設けたものであるが、保持部材２の外管側にも隙間を設けて、保持部材２の外周面が外管４の内周面に接触する程度に内管１と保持部材２を同時に拡径するようにしてもよい。
【００３０】
図４乃至図６は第１実施例を示す。
【００３１】
本第１実施例は、前記参考例における嵌合された保持部材２の前後における内管に突起を形成する例である。
【００３２】
先ず、図４（ａ）に示すような他端部Ｂに縮径部４ａを形成した直管状の金属製の外管４内に、該外管４より薄肉の金属製の内管１を、その他端部Ｂを前記外管４の縮径部４ａに圧入するとともに該部をスポット溶接などで固着して図４（ａ）に示すような内管１と外管４との間に空間５を有する二重管を形成する。
【００３３】
次に、前記空間５内に、その開口部５ａから粒状物などを充填した後に前記開口部５ａを閉塞し、この状態で適宜な曲げ加工手段によって前記の二重管を所定の形状、例えば、図４（ｂ）に示すような形状に曲げ加工する。
【００３４】
次に、前記の開口部５ａを開き、前記の粒状物を排出除去した後、二重管の一端部Ａ側である前記開口部５ａから前記参考例と同様の保持部材２を図３（ｃ）に示すように挿入し、その保持部材２を所定位置に配置する。この保持部材２の内径は、前記参考例と同様に、内管１の外径より若干大きく形成され、保持部材２と内管１との間に前記と同様な隙間ｔが形成されるようになっている。また、保持部材２の外径は、その保持部材２の外周面が外管４に接触する程度に設定されている。
【００３５】
次に、前記保持部材２が挿入配置された近傍の内管１内に図４（ｃ）に示すように分割型６と中心型７を挿入する。
【００３６】
この分割型６は、円筒状の型を周方向に複数に分割、図の実施例では図５及び図６に示すように８分割したもので、その分割片６ａが径方向に移動可能に備えられ、また、中心部は、軸方向の内側が縮径するテーパ面６ｂに形成されている。更に、該分割型６、すなわち各分割片６ａの外周には軸方向に所定の間隔Ｌ１ 離れて２個の突起６ｃ，６ｄが設けられている。この間隔Ｌ１ は、前記保持部材２の軸方向長Ｌ２よりも長く設定されているが、略同長でもよい。更に、各突起６ｃ，６ｄは、図５及び図６に示すように、各分割片６ａ毎の全周にわたって形成されている。
【００３７】
また、前記分割型６、すなわち各分割片６ａにおける両突起６ｃ，６ｄの間の外面は、該外面を除く一般面、すなわち両端部の外面６ｆ，６ｇに対して、前記間隔ｔと少なくとも同じ大きさ分だけ大径に設定した拡径面６ｅに形成されている。なお、前記両端部の外面６ｆ，６ｇは無くてもよい。
【００３８】
前記分割型６の各分割片６ａは、図示しない縮径手段により縮径方向に付勢されている。更に、分割型６は、その軸方向に移動可能に備えられ、図示しない駆動手段によって内管１に対して挿入したり外脱できるようになっている。
【００３９】
また、前記中心型７は、先細状のテーパ面７ａで形成され、そのテーパ面７ａは前記分割型６のテーパ面６ａと合致するように形成されており、図示しない油圧装置などの駆動手段により軸方向に進退移動できるようになっている。
【００４０】
そして、図４（ｃ）に示すように、前記分割型６を縮径状態において、その両突起６ｃ，６ｄ間の拡径面６ｅが前記挿入された保持部材２の部分に位置するように内管１内へ挿入し、次で、中心型７を図４（ｃ）の矢印方向へ移動して、分割型６の各分割片６ａを径方向に押し広げる。これにより、図４（ｄ）に示すように分割型６に設けた両突起６ｃ，６ｄによって該部の内管が外方へ押し曲げられて塑性変形し、内管１に、保持部材２の前後に位置して凸部１ａ，１ｂが形成される。また、同時に、分割型６における両突起６ｃ，６ｄ間の拡径面６ｅによって、内管１における前記両凸部１ａ，１ｂ間の部分１ｃが図４（ｄ）に示すように拡径され、該部分１ｃの外周面と保持部材２の内周面が相互に接触する。
【００４１】
次に、前記の中心型７を後退させて分割型６の各分割片６ａを縮径移動させた後、分割型６と中心型７を内管１より抜き外す。
【００４２】
以上により、内管と外管４の一端部Ａにおいて、これらの間に保持部材２が、両管１，４に接触して配置され、他端部Ｂ側の内管１と外管４が固着され、更に、中間部が屈曲した二重管よりなる排気管が製造される。
【００４３】
なお、本第１実施例は、保持部材２の内管側にのみ隙間ｔを設けたものであるが、保持部材２の外管側にも隙間を設けて、保持部材２の外周面が外管４の内周面に接触する程度に内管１と保持部材２を同時に拡径するようにしてもよい。
【００４４】
図７は第２実施例を示す。
【００４５】
本第２実施例は、直管状の内外管において、先に内管に前記第１実施例と同様の拡径加工を行って保持部材を備え、その後に外管を嵌合する方式の例である。
【００４６】
先ず、図７（ａ）に示すように、直管状の金属製の内管１における一端部Ａの外周に、前記第１参考例と同様の保持部材２を、前記と同様に隙間ｔを有して嵌合する。
【００４７】
次に、前記第１実施例と同様の分割型６と中心型７を、図７（ａ）に示すように、内管１の一端部Ａ側に前記第１実施例と同様に挿入する。
【００４８】
次に、中心型７を図７（ａ）から図７（ｂ）に示すように挿入して分割型６の各分割片６ａを拡径し、前記第１実施例と同様に、内管１に両凸部１ａ，１ｂを形成すると同時に両凸部１ａ，１ｂ間の部分１ｃを拡径して、該部分１ｃの外周面と保持部材２の内周面を相互に接触させる。
【００４９】
次に、前記の中心型７を後退させて分割型６の各分割片６ａを縮径移動させた後、分割型６と中心型７を内管１より抜き外す。
【００５０】
次に、図７（ｃ）に示すように、前記保持部材２の外周に嵌合する径で、かつ、他端部Ｂに前記内管１の外周に嵌合する縮径部４ａを形成した外管４に、その大径側開口部から前記内管１および保持部材２を挿入し、内管１の他端部Ｂ側と外管４の縮径部４ａをスポット溶接などで固着する。なお、外管４は、その肉厚が、内管１の肉厚よりも厚いものが使用される。
【００５１】
以上により、図７（ｃ）に示すような、保持部材２の内周面が内管１に接触し、保持部材２の外周面が外管４に接触し、かつ、内管１と外管４との間に空間５を有する二重管からなる排気管が製造される。
【００５２】
前記各参考例及び実施例は、保持部材２を管の端部に設けた例であるが、前記第１及び第２実施例においては、保持部材２を管の中央部に配置するとともに該中央部に分割型６と中心型７を配置して内管１を拡径加工してもよい。また、第１及び第２参考例においては、保持部材２を管の中央部に配置するとともに型３を周方向に複数分割された分割型にして第１実施例のような中心型で分割片を拡径する構造とし、この型を保持部材２が配置された管の中央部に配置して内管１を拡径加工してもよい。
【００５３】
更に、前記各実施例においては、内管１における保持部材２と接触する部分を、内管１の全周にわたって均一に拡径したが、内管１と保持部材２が周方向において部分的に接触するように内管１を拡径してもよい。また、前記凸部１ａ，１ｂを、内管１の周方向において部分的に設けてもよい。
【００５４】
また、前記各実施例のように、内管を拡径するようにしたことにより、次のような効果がある。排気管を構成する二重管は、熱容量の観点から内管が外管よりも薄肉に形成されることが多いため、前記各実施例のように内管側を拡径加工することにより、その拡径加工が容易になり、保持部材への管の接触加工が容易になる。
【００５５】
【発明の効果】
以上のようであるから、請求項１記載の発明によれば、保持部材と内管とが相互に接触しているため、エンジンの振動による排気管の振動を抑制でき、振動によって保持部材が内管によって叩かれることがなく、前記従来のような異音の発生を防止できる。
【００５６】
請求項２記載の発明によれば、内管の外周に保持部材を嵌合する際に、保持部材と内管との間に隙間を有するため、その保持部材の嵌合組付け作業が容易になる。しかも、このように隙間を形成しても、保持部材の嵌合後に内管を拡径して該保持部材と内管とを接触させるため、前記のような組付け後の異音の発生を防止することができる。
【００５７】
また、凸部によって保持部材の移動を抑制できる排気管を製造できる。
【００５８】
請求項３記載の発明によれば、前記の保持部材と内管とを接触させる工程と凸部を形成する工程が同時に行え、作業時間やコストの面で有効である。
【図面の簡単な説明】
【図１】 本発明の第１参考例を示す断面図で、（ａ）乃至（ｃ）はその製造工程を示す。
【図２】 図１（ａ）におけるＣ−Ｃ線断面図。
【図３】 本発明の第２参考例を示す断面図で、（ａ）乃至（ｃ）はその製造工程を示す。
【図４】 本発明の第１実施例を示す断面図で、（ａ）乃至（ｄ）はその製造工程を示す。
【図５】 図４の実施例に使用する分割型と中心型を示すもので、図４（ｃ）の状態を示す断面図。
【図６】 図４の実施例に使用する分割型と中心型を示すもので、図４（ｄ）の状態を示す断面図。
【図７】 本発明の第２実施例を示す断面図で、（ａ）乃至（ｃ）はその製造工程を示す。
【図８】 従来の排気管を示す断面図。
【符号の説明】
１ 内管
１ａ，１ｂ 凸部
１ｃ，１ｄ 内管の拡径部
２ 保持部材
３ 型
４ 外管
５ 空間
６ 分割型
６ｃ，６ｄ 突起
６ｅ 拡径面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust pipe and a method for manufacturing the exhaust pipe.
[0002]
[Prior art]
Conventionally, as an exhaust pipe for an internal combustion engine, an inner pipe 101 and a space 102 are provided on the outer periphery thereof as shown in FIG. 8 in order to improve sound insulation and to keep exhaust gas warm and improve catalyst purification performance. A double pipe composed of the arranged outer pipe 103 is employed.
[0003]
Such double tubes are connected to each other at both ends thereof, but in order to enable relative movement due to a difference in thermal expansion between the inner tube 101 and the outer tube 103, the other end sides of the inner and outer tubes 101, 103 are used. B is fixed to each other by spot welding or the like, and one end A is slidably disposed on a holding member (spacer) 104 formed by pressing a stainless steel wire braided between the inner tube 101 and the outer tube 103 into a ring shape. Configured.
[0004]
As an arrangement method of the holding member 104, in FIG. 8, first, a first bulging portion 105 protruding outward is formed on one end side A of the inner tube 101, and then the ring-shaped holding member 104 is formed. For example, Japanese Patent Laid-Open No. 8-4524 discloses a method in which the second bulging portion 106 is formed.
[0005]
[Problems to be solved by the invention]
In the case where the ring-shaped holding member 104 is disposed as in the conventional case, the inner diameter of the holding member 104 is slightly larger than the outer diameter of the inner tube 101 in consideration of the assembly work of the holding member 104. Alternatively, it is necessary to make the outer diameter of the holding member 104 slightly smaller than the inner diameter of the outer tube 103 and provide a gap 107 between the holding member 104 and the inner tube 101 or the outer tube 103.
[0006]
However, in the conventional method for manufacturing a double pipe, since the gap 107 is formed even after the holding member 104 is inserted, the double pipe is mounted on a vehicle as an exhaust pipe of an internal combustion engine. In this case, the exhaust pipe is likely to vibrate due to the vibration of the engine, and the holding member 104 is hit by the inner pipe 101 or the outer pipe 103 due to the vibration, and the gap 107 is enlarged from the initial size, and noise is generated. There was a fear.
[0007]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an exhaust pipe and a method for manufacturing the exhaust pipe that can prevent the generation of abnormal noise as described above without deteriorating the assembly workability of the holding member. .
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a first invention according to claim 1 is arranged in an inner tube, an outer tube arranged with a space around the inner tube, and a part of the space portion. An exhaust pipe having a ring-shaped holding member and a convex portion formed on the inner pipe before and after the holding member, wherein the outer diameter of the inner pipe between the two convex portions is outside the inner pipe outside the convex portion. The exhaust pipe is characterized in that it is larger than the diameter and the inner pipe between the two convex portions and the holding member are in contact with each other.
[0009]
A second aspect of the invention includes an inner tube, an outer tube disposed with a space around the inner tube, and a ring-shaped holding member disposed in a part of the space portion. An exhaust pipe manufacturing method comprising:
After fitting the holding member on the outer periphery of the inner tube with a gap between the inner tube and the inner tube before and after the holding member, a convex portion is provided, and the holding member and the inner tube are The exhaust pipe manufacturing method is characterized in that the diameter of the inner pipe between the two convex portions is expanded so as to contact at least.
[0011]
A third invention of claim 3, wherein, in the second invention, in the interior of the inner tube at a portion where the holding member is disposed, a projection to form the two projecting portions of the inner tube, the double convex portion A mold having an enlarged surface for enlarging the inner tube between them is arranged, and the mold is moved outward in the radial direction to simultaneously form both the convex portions and increase the diameter between the two convex portions. The exhaust pipe manufacturing method is characterized in that it is configured as described above.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention shown in FIGS. 1 to 7 will be described.
[0013]
1 and 2 show a first reference example.
[0014]
Manufacturing method of the reference example, first, the outer periphery of the end portion A of the inner tube 1 of the straight pipe metal constituting the exhaust pipe, the holding member 2 by press molding a metal thin wire was braided in hosiery shape like a ring Fit as shown in FIG.
[0015]
As shown in FIG. 1A, the inner diameter of the holding member 2 is set slightly larger than the outer diameter of the inner tube 1, and a predetermined gap (clearance) t is provided between the inner tube 1 and the holding member 2. It is supposed to be formed. The size of the gap t is set to such an extent that the holding member 2 can be easily inserted into the inner tube 1, but taking into account variations in the outer diameter of the inner tube 1 and the inner diameter of the holding member 2 and assembly workability. It is usually set to about 0.2 mm.
[0016]
By having such a gap t, the assembly work of the holding member 2 to the inner tube 1 can be easily performed.
[0017]
Next, the diameter of the inner tube 1 in the vicinity where the holding member 2 is inserted and arranged is expanded as shown in FIG. As this diameter expansion method, for example, as shown in FIG. 1A, a cylindrical mold surface portion 3a having a diameter at least larger than the raw tube of the inner tube 1 by the gap t, and a tapered tapered surface 3b at the tip portion. The mold 3 is used, and the mold 3 is press-fitted from the opening at one end A of the inner tube 1 by a driving means (not shown), and the holding member 2 in the inner tube 1 is disposed as shown in FIG. The one end portion A in the vicinity is expanded. 1d shows the diameter-expanded part expanded.
[0018]
As described above, a method for expanding the diameter of the inner tube 1 may employ a known diameter expanding method in addition to the method of the reference example.
[0019]
Further, the diameter expansion amount of the inner tube 1 is such that at least the gap t becomes zero and the inner tube 1 and the holding member 2 come into contact with each other, but the holding member 2 is somewhat compressed. The diameter may be increased as described above.
[0020]
In addition, before or after the diameter expansion process of the inner tube 1, the holding member 2 and the inner tube 1 may be fixed to each other by spot welding or the like to prevent the holding member 2 from moving in the axial direction. .
[0021]
Next, after the mold 3 is removed, as shown in FIG. 1 (c), the diameter is fitted to the outer periphery of the holding member 2 and the other end B is fitted to the outer periphery of the inner tube 1. The inner tube 1 and the holding portion 2 are inserted into the metal outer tube 4 formed with the reduced diameter portion 4a to be joined from the large-diameter side opening, and the other end B side of the inner tube 1 and the outer tube 4 The reduced diameter portion 4a is fixed by spot welding or the like. Note that the outer tube 4 having a wall thickness greater than that of the inner tube 1 is used.
[0022]
As described above, as shown in FIG. 1C, the inner peripheral surface of the holding member 2 is in contact with the enlarged diameter portion 1d of the inner tube 1, the outer peripheral surface of the holding member 2 is in contact with the outer tube 4, and the inner An exhaust pipe composed of a double pipe having a space 5 between the pipe 1 and the outer pipe 4 is manufactured.
[0023]
FIG. 3 shows a second reference example.
[0024]
The second reference example shows a manufacturing method in which a double pipe is formed first, and a holding member is arranged on the double pipe by inner pipe processing similar to the first reference example.
[0025]
First, in the straight tubular metal outer tube 4 in which the reduced diameter portion 4a is formed at the other end B as shown in FIG. 3A, the metal inner tube 1 thinner than the outer tube 4, The other end B is press-fitted into the reduced diameter portion 4a of the outer tube 4 and the portion is fixed by spot welding or the like, and a space 5 is formed between the inner tube 1 and the outer tube 4 as shown in FIG. To form a double tube.
[0026]
Next, the holding member 2 similar to the above is inserted into the space 5 from the opening of the space 5 as shown in FIG. 3B, and the holding member 2 is arranged on the outer periphery on the one end A side of the inner tube 1. To do. At this time, since the gap t as described above is provided between the holding member 2 and the inner tube 1, the assembling work of the holding member 2 with respect to the inner tube 1 can be easily performed.
[0027]
Then, by the first reference example and a similar type 3, the inner tube 1 in the vicinity of the holding member 2 is disposed to the first reference example as well as expanded as shown in FIG. 3 (c), The inner tube 1 of the enlarged diameter portion 1d is brought into contact with the holding member 2. The diameter of the inner tube 1 may be increased so that the holding member 2 is slightly compressed to prevent the holding member 2 from moving in the axial direction.
[0028]
And the double pipe as shown in FIG.1 (c) of the said 1st reference example is manufactured by extracting the said type | mold 3. FIG.
[0029]
In the second reference example, the gap t is provided only on the inner tube side of the holding member 2, but a gap is also provided on the outer tube side of the holding member 2 so that the outer peripheral surface of the holding member 2 is outside. The inner tube 1 and the holding member 2 may be increased in diameter to the extent that they contact the inner peripheral surface of the tube 4.
[0030]
4 to 6 show the first embodiment.
[0031]
The first embodiment is an example in which protrusions are formed on the inner tube before and after the fitted holding member 2 in the reference example.
[0032]
First, in the straight tubular metal outer tube 4 formed with a reduced diameter portion 4a at the other end B as shown in FIG. 4 (a), the metal inner tube 1 thinner than the outer tube 4, The other end B is press-fitted into the reduced diameter portion 4a of the outer tube 4 and the portion is fixed by spot welding or the like, and a space 5 is formed between the inner tube 1 and the outer tube 4 as shown in FIG. To form a double tube.
[0033]
Next, after filling the space 5 with a granular material or the like from the opening 5a, the opening 5a is closed, and in this state, the double pipe is formed into a predetermined shape by an appropriate bending means, for example, Bending is performed into a shape as shown in FIG.
[0034]
Next, after opening the opening 5a and discharging and removing the particulate matter, the holding member 2 similar to the reference example is removed from the opening 5a on the one end A side of the double pipe as shown in FIG. ), And the holding member 2 is arranged at a predetermined position. The inner diameter of the holding member 2, as in the reference example, as slightly is larger than the outer diameter of the inner tube 1, the same gap t is formed between the holding member 2 and the inner tube 1 It has become. Further, the outer diameter of the holding member 2 is set such that the outer peripheral surface of the holding member 2 comes into contact with the outer tube 4.
[0035]
Next, as shown in FIG. 4C, the split mold 6 and the central mold 7 are inserted into the inner tube 1 in the vicinity where the holding member 2 is inserted and arranged.
[0036]
The split mold 6 is formed by dividing a cylindrical mold into a plurality of parts in the circumferential direction. In the illustrated embodiment, the split mold 6 is divided into eight as shown in FIGS. 5 and 6, and the split piece 6a is provided so as to be movable in the radial direction. In addition, the central portion is formed on a tapered surface 6b whose inner diameter in the axial direction is reduced in diameter. Further, a predetermined interval L 1 in the axial direction is provided on the outer periphery of the split mold 6, that is, each split piece 6a. Two protrusions 6c and 6d are provided apart from each other. This interval L 1 , The the holding is set longer than the member axially length L 2 of 2, it may be substantially the same length. Furthermore, each protrusion 6c, 6d is formed over the entire circumference of each divided piece 6a as shown in FIGS.
[0037]
Further, the outer surface between the projections 6c and 6d in the split mold 6, that is, each split piece 6a, is at least as large as the interval t with respect to the general surface excluding the outer surface, that is, the outer surfaces 6f and 6g at both ends. It is formed on the enlarged-diameter surface 6e set to a large diameter. In addition, the outer surfaces 6f and 6g of the both end portions may be omitted.
[0038]
Each divided piece 6a of the split mold 6 is urged in the diameter reducing direction by a diameter reducing means (not shown). Further, the split mold 6 is provided so as to be movable in its axial direction, and can be inserted into and removed from the inner tube 1 by a driving means (not shown).
[0039]
Further, the central die 7 is formed by a tapered taper surface 7a, and the taper surface 7a is formed so as to coincide with the taper surface 6a of the split die 6, and is driven by driving means such as a hydraulic device (not shown). It can move forward and backward in the axial direction.
[0040]
Then, as shown in FIG. 4 (c), when the split mold 6 is in a reduced diameter state, the inner diameter surface 6e between the protrusions 6c, 6d is positioned at the portion of the inserted holding member 2. It inserts in the pipe | tube 1, Next, the center type | mold 7 is moved to the arrow direction of FIG.4 (c), and each division piece 6a of the division | segmentation type | mold 6 is expanded in a radial direction. As a result, as shown in FIG. 4 (d), the inner tube of the portion is pushed and bent outwardly by both projections 6c and 6d provided on the split mold 6, and the inner tube 1 has the holding member 2 deformed. Convex portions 1a and 1b are formed at the front and rear. At the same time, the diameter 1e between the protrusions 6c, 6d in the split mold 6 is expanded in diameter as shown in FIG. The outer peripheral surface of the portion 1c and the inner peripheral surface of the holding member 2 are in contact with each other.
[0041]
Next, after the central die 7 is retracted and the divided pieces 6 a of the split die 6 are reduced in diameter, the split die 6 and the central die 7 are removed from the inner tube 1.
[0042]
As described above, in the one end portion A of the inner tube and the outer tube 4, the holding member 2 is disposed between them in contact with both the tubes 1 and 4, and the inner tube 1 and the outer tube 4 on the other end B side are connected. An exhaust pipe made of a double pipe which is fixed and has a bent middle part is manufactured.
[0043]
In the first embodiment, the gap t is provided only on the inner tube side of the holding member 2, but a gap is also provided on the outer tube side of the holding member 2 so that the outer peripheral surface of the holding member 2 is outside. The inner tube 1 and the holding member 2 may be increased in diameter to the extent that they contact the inner peripheral surface of the tube 4.
[0044]
FIG. 7 shows a second embodiment.
[0045]
The second embodiment is an example of a straight tubular inner / outer pipe, in which the inner pipe is first subjected to the same diameter expansion processing as in the first embodiment to have a holding member, and then the outer pipe is fitted. is there.
[0046]
First, as shown in FIG. 7A, the holding member 2 similar to that of the first reference example is provided on the outer periphery of the one end A of the straight tubular metal inner tube 1, and the gap t is provided as described above. And fit.
[0047]
Next, the first embodiment and the same split 6 and the center mold 7, as shown in FIG. 7 (a), inserted as in the first embodiment to the one end A side of the inner tube 1.
[0048]
Next, the central die 7 is inserted as shown in FIGS. 7 (a) to 7 (b) to increase the diameter of each divided piece 6a of the divided die 6, and the inner tube 1 is the same as in the first embodiment. At the same time as forming both convex portions 1a and 1b, the diameter of the portion 1c between the convex portions 1a and 1b is increased, and the outer peripheral surface of the portion 1c and the inner peripheral surface of the holding member 2 are brought into contact with each other.
[0049]
Next, after the central die 7 is retracted and the divided pieces 6 a of the split die 6 are reduced in diameter, the split die 6 and the central die 7 are removed from the inner tube 1.
[0050]
Next, as shown in FIG. 7 (c), a diameter-reduced portion 4 a that fits on the outer periphery of the holding member 2 and that fits on the outer periphery of the inner tube 1 is formed at the other end B. The inner tube 1 and the holding member 2 are inserted into the outer tube 4 from the large-diameter side opening, and the other end B side of the inner tube 1 and the reduced diameter portion 4a of the outer tube 4 are fixed by spot welding or the like. In addition, the outer tube 4 is thicker than the inner tube 1.
[0051]
7C, the inner peripheral surface of the holding member 2 contacts the inner tube 1, the outer peripheral surface of the holding member 2 contacts the outer tube 4, and the inner tube 1 and the outer tube Thus, an exhaust pipe composed of a double pipe having a space 5 between them is manufactured.
[0052]
Each reference examples and examples are examples in which a holding member 2 to the end of the tube, the in the first and second embodiment, the central as well as arranging the holding member 2 in the central portion of the tube The inner pipe 1 may be subjected to diameter expansion processing by arranging the split mold 6 and the center mold 7 in the part. In the first and second reference example, the split pieces in centric as in the first embodiment with a plurality divided split mold 3 in the circumferential direction together with arranging the holding member 2 in the central portion of the tube The diameter of the inner tube 1 may be increased by arranging the mold at the center of the tube on which the holding member 2 is disposed.
[0053]
Furthermore, in each said Example, although the part which contacts the holding member 2 in the inner tube 1 was expanded uniformly over the perimeter of the inner tube 1, the inner tube 1 and the holding member 2 are partially in the circumferential direction. The inner tube 1 may be expanded in diameter so as to come into contact. Further, the convex portions 1 a and 1 b may be partially provided in the circumferential direction of the inner tube 1.
[0054]
In addition, as described in each of the above embodiments, the diameter of the inner tube is increased, thereby providing the following effects. The double pipe constituting the exhaust pipe is often formed with a thinner inner pipe than the outer pipe from the viewpoint of heat capacity. The diameter expansion process is facilitated, and the contact process of the tube to the holding member is facilitated.
[0055]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the holding member and the inner pipe are in contact with each other, the vibration of the exhaust pipe due to the vibration of the engine can be suppressed. The occurrence of abnormal noise as in the conventional case can be prevented without being hit by the tube.
[0056]
According to the second aspect of the present invention, when the holding member is fitted to the outer periphery of the inner tube, there is a gap between the holding member and the inner tube, so that the fitting operation of the holding member is easy. Become. Moreover, even if the gap is formed in this way, the inner tube is expanded after fitting the holding member, and the holding member and the inner tube are brought into contact with each other. Can be prevented.
[0057]
Moreover , the exhaust pipe which can suppress a movement of a holding member with a convex part can be manufactured.
[0058]
According to the third aspect of the invention, the step of bringing the holding member into contact with the inner tube and the step of forming the convex portion can be performed simultaneously, which is effective in terms of working time and cost.
[Brief description of the drawings]
FIGS. 1A to 1C are cross-sectional views showing a first reference example of the present invention, wherein FIGS.
FIG. 2 is a cross-sectional view taken along line CC in FIG.
FIGS. 3A to 3C are cross-sectional views showing a second reference example of the present invention, wherein FIGS.
FIGS. 4A to 4D are cross-sectional views showing a first embodiment of the present invention, wherein FIGS.
FIG. 5 is a sectional view showing a state of FIG. 4C, showing a split mold and a center mold used in the embodiment of FIG. 4;
6 is a cross-sectional view showing the divided type and the central type used in the embodiment of FIG. 4 and showing the state of FIG. 4 (d).
FIGS. 7A to 7C are cross-sectional views showing a second embodiment of the present invention, wherein FIGS.
FIG. 8 is a cross-sectional view showing a conventional exhaust pipe.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner pipe 1a, 1b Convex part 1c, 1d Diameter expansion part 2 Inner pipe 2 Holding member 3 Type | mold 4 Outer pipe 5 Space 6 Divided type 6c, 6d Protrusion 6e Diameter expansion surface

Claims (3)

内管と、該内管の外周に空間を設けて配置した外管と、前記空間部の一部に配置されたリング状の保持部材と、該保持部材の前後において内管に形成した凸部を有する排気管であって、前記両凸部間の内管の外径が前記凸部の外側の内管の外径よりも大きく、かつ、前記両凸部の間の内管と前記保持部材とが接触していることを特徴とする排気管。An inner tube, an outer tube disposed with a space around the inner tube, a ring-shaped holding member disposed in a part of the space, and a convex portion formed on the inner tube before and after the holding member An outer diameter of the inner pipe between the two convex portions is larger than an outer diameter of the inner pipe outside the convex portion, and the inner pipe and the holding member between the two convex portions. An exhaust pipe characterized by being in contact with. 内管と、該内管の外周に空間を設けて配置した外管と、前記空間部の一部に配置されたリング状の保持部材とを備えた排気管の製造方法であって、
前記内管の外周に前記保持部材を、内管との間に隙間を設けて嵌合した後に、前記保持部材の前後の内管に凸部を設けるとともに、前記保持部材と前記内管とが少なくとも接触するように前記両凸部間の内管を拡径することを特徴とする排気管の製造方法。An exhaust pipe manufacturing method comprising an inner pipe, an outer pipe arranged with a space around the inner pipe, and a ring-shaped holding member arranged in a part of the space part,
After fitting the holding member on the outer periphery of the inner tube with a gap between the inner tube and the inner tube before and after the holding member, a convex portion is provided, and the holding member and the inner tube are A method of manufacturing an exhaust pipe, wherein the inner pipe between both convex portions is expanded so as to make at least contact. 前記保持部材が配置された部分における内管の内部に、内管の前記両凸部を形成する突起と、前記両凸部間の内管を拡径する拡径面を形成した型を配置し、該型を径方向の外側へ移動して、前記両凸部の形成と、該両凸部間の拡径を同時に行うようにしたことを特徴とする請求項２記載の排気管の製造方法。Inside the inner tube at the portion where the holding member is disposed, a mold is formed in which a projection forming the both convex portions of the inner tube and a diameter-expanding surface for expanding the inner tube between the both convex portions are formed. 3. The method of manufacturing an exhaust pipe according to claim 2 , wherein the mold is moved outward in the radial direction so that the formation of the two convex portions and the diameter expansion between the two convex portions are simultaneously performed. .
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DE102018205909A1 (en) * 2018-04-18 2019-10-24 Ford Global Technologies, Llc Exhaust manifold with air gap insulation
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JPH06299848A (en) * 1993-04-12 1994-10-25 Toyota Motor Corp Exhaust pipe structure for internal combustion engine
JPH084524A (en) * 1994-06-20 1996-01-09 Calsonic Corp Bent double exhausting device and its manufacture
JPH0828257A (en) * 1994-07-11 1996-01-30 Toyota Motor Corp Double exhaust pipe
JPH1061424A (en) * 1996-08-19 1998-03-03 Sango Co Ltd Noise eliminator and its manufacture
JPH10266844A (en) * 1997-03-25 1998-10-06 Calsonic Corp Double pipe type exhaust manifold

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58162394U (en) * 1982-04-23 1983-10-28 新日本製鐵株式会社 Insulated multi-layer pipe with pipe end processing
JPH06106672A (en) * 1992-09-25 1994-04-19 Toyota Motor Corp Damping metal pipe
JPH06299848A (en) * 1993-04-12 1994-10-25 Toyota Motor Corp Exhaust pipe structure for internal combustion engine
JPH084524A (en) * 1994-06-20 1996-01-09 Calsonic Corp Bent double exhausting device and its manufacture
JPH0828257A (en) * 1994-07-11 1996-01-30 Toyota Motor Corp Double exhaust pipe
JPH1061424A (en) * 1996-08-19 1998-03-03 Sango Co Ltd Noise eliminator and its manufacture
JPH10266844A (en) * 1997-03-25 1998-10-06 Calsonic Corp Double pipe type exhaust manifold

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