JP3886340B2

JP3886340B2 - Inner and outer double pipe type exhaust pipe

Info

Publication number: JP3886340B2
Application number: JP2001126483A
Authority: JP
Inventors: 智之武若; 勝則船橋; 尚史車古
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2001-04-24
Filing date: 2001-04-24
Publication date: 2007-02-28
Anticipated expiration: 2021-04-24
Also published as: CN1382900A; JP2002317630A; CN1270059C; KR100453874B1; KR20020082746A

Description

【０００１】
【発明の属する技術分野】
本願発明は自動２輪車等に使用される内外二重管式排気管に係り、特に長期間使用してもビビリ音を発生させないようにしたものに関する。
【０００２】
【従来の技術】
エンジンからマフラーの間を接続する排気管を内外二重管構造とし、その後端部にて外管に半径方向内側へ向かって突出するセパレート突起を形成し、このセパレート突起を内管に当接させて内管を外管と所定間隔を保つように支持するとともに、熱膨張による伸び（以下、熱伸びという）で外管に対する内管の相対的な移動を許容するため内管を摺動自在に当接支持するようにしたものが公知である（特開平１１−３０３６３２号参照）。
【０００３】
【発明が解決しようとする課題】
ところで、上記構造においても長期間使用することによりセパレート突起と内管の間に摩耗による微少な摩耗間隙が生じ、この摩耗間隙により内管が自励振動してビビリ音を発生することがある。そこで、本願発明は係るビビリ音の発生を有効に防止することを目的とする。
【０００４】
【課題を解決するための手段】
上記課題を解決するため本願発明に係る内外二重管式排気管は、外管又は内管のいずれか一方側から他方側へ突出して当接するセパレート突起を周方向へ所定間隔で複数設け、このセパレート突起により内管を外管の内側へ所定間隔に保持するとともに、前記セパレート突起の当接部にて当接相手側を摺動可能に支持した内外二重管式排気管において、
前記内外管に形成される間隙内に、前記内管を前記セパレート突起へ密接させるための抑え部材を圧入したことを特徴とする。
【０００５】
このとき、前記セパレート突起を外管から内管へ向かって形成し、かつ前記抑え部材を外管へ溶接により固定するようにしてもよい。
【０００６】
【発明の効果】
外管と内管との間隙に抑え部材を圧入すると、この抑え部材により内管をセパレート突起へ強く押し当てる。この状態で長期間使用すると、セパレート突起と当接相手との間に摩耗が生じても、抑え部材の押圧により内管とセパレート突起の密着を保つので、内管が自励振動を生じず、その結果ビビリ音の発生を防止できる。
【０００７】
このとき、抑え部材を外管へ溶接すれば抑え部材を確実に位置決めでき、抑え部材の圧入を簡単にできる。しかも、摺動面に溶接痕が残らないので、内管の摺動を確保するために抑え部材の摺動面に対して特別な仕上げ加工を施す必要もない。
【０００８】
【発明の実施の形態】
以下、図面に基づいて第１実施例を説明する。図１は本実施例の内外二重管式排気管を適用した自動２輪車の側面図、図２は本実施例の内外二重管式排気管を含む排気系装置の側面図、図３は図２の３−３線断面図、図４は図３の４−４線に沿う断面図、図５は抑え部材の溶接部を示す図、図６は同溶接構造示す拡大断面図である。
【０００９】
図１に示すように、排気管１は排気上流側端部（以下、前端部という）をエンジン２の排気口へ接続し、ここから延出した部分はエンジン２の前方から下方へ回り込んで車体後方へ伸び、排気下流側端部（以下、後端部という）をマフラー３へ接続し、エンジン２の排気ガスをマフラー３へを導き、さらにここから車体後方空間へ排出するようになっている。
【００１０】
図中の符号４はヘッドパイプ、５は車体フレーム、６はピボット軸、７は前端部をピボット軸６により車体へ揺動自在に支持され後端部にて図示省略の後輪を支持するリヤスイングアーム、８は車体フレームとリヤスイングアームの間に設けられるリヤクッションユニットである。
【００１１】
図２において、排気管１は外管１０と内管１１との内外二重管構造をなす。排気管１の前端にはフランジ１２が設けられ、ここでエンジン２の排気口へ取付けられる。排気管１の後端はジョイントパイプ１３に嵌合接続する。
【００１２】
ジョイントパイプ１３はマフラー３の内部を排気下流側へ延出し、排気ガスをマフラー３の本体部内へ導く。排気管１とジョイントパイプ１３の接続部の上にはマフラー３の前端部側に形成された細径部１４が被さって、ジョイントパイプ１３と共に外管１０の外表面へ溶接される。
【００１３】
図３及び図４に示すように、外管１０及び内管１１はそれぞれ鉄等の適宜金属からなる丸パイプ状であり、外管１０に対して内管１１はその内側へ所定間隙Ｄを保つように略同心配置され、この同心的に保持するためのセパレート突起１５が排気管１の後端部に外管１０から内管１１へ向かって突出形成されている。
【００１４】
セパレート突起１５は外管１０の後端部をプレス成形により半径方向内側へ一体に突出形成して内管１１の外周へ当接支持させたものであり、本実施例の場合、外管１０の周方向へ等間隔で４個形成され、その突出高さはほぼ外管１０と内管１１の間隙Ｄと同程度である。また、セパレート突起１５の内管１１に対する当接部は、内管１１の熱伸びによる伸縮を可能にするため摺動自在になっている。
【００１５】
図４に明らかなように、外管１０と内管１１は後端部にてセパレート突起１５部分で一体化されるが、それより前方では内管１１が外管１０の内側へ同心配置されて所定間隔Ｄを維持している。
【００１６】
図３に明らかなように、隣り合うセパレート突起１５、１５の間は内管１１側から半径方向外方へ突出する外方突部１６をなし、その内側に間隙１７が形成される。外方突部１６は内管１１側から外管１０を見たときの表現であり、外管１０の後端部のうちセパレート突起１５を形成したとき非成形部として残った部分である。したがって外方突部１６の外周部は外管１０における本来の外径部分であり、間隙１７の半径方向における幅は所定間隔Ｄとなる。
【００１７】
この間隙１７のうちの一つに抑え部材１８が圧入され、プラグ１９により外方突部１６へプラグ溶接されている。抑え部材１８は鉄等の適宜金属材料からなり、その肉厚Ｔは間隙１７の半径方向幅すなわち外管１０と内管１１の所定間隔Ｄよりも若干大きくなるように設定され、ハンマーで叩くことにより押し込まれる程度の軽圧入にて圧入される。
【００１８】
図４及び図６に明らかなように、抑え部材１８の先に圧入される端部はアール状もしくはテーパー状等、圧入を容易にするため薄形に形成され、かつ図５に示すようセパレート突起１５の長さより若干短い程度の長さを有し、また、図３に示すように、内管１１の外周へ摺接するように円弧状に曲げられている。
【００１９】
図５は図４のＹ矢示方向から外管１０のセパレート突起１５及び抑え部材１８を示す図であり、抑え部材１８は外管１０の後端部である外方突部１６に形成された貫通穴２０へ挿入されたプラグ１９を介して外管１０とプラグ溶接される。図６のＡはこの溶接構造を模式的に示す図５の６−６線断面である。
【００２０】
なお、抑え部材１８の固定はプラグ溶接に限らず、他の適宜溶接方法が可能である。図６のＢは抑え部材１８と外管１０の端面相互を隅肉溶接している。このようにしても、溶接ビードが内管１１まで達しない限り問題はなく、抑え部材１８と内管１１の摺動を可能にしている。
【００２１】
次に本実施例の作用を説明する。図３に示すように、間隙１７へ抑え部材１８を圧入することにより、内管１１は若干の弾性変形を伴って反対側のセパレート突起１５へ押しつけられる。この状態で内管１１が熱伸びにより外管１０に対して相対的に伸びると、セパレート突起１５及び抑え部材１８に対して摺動し、冷却すると収縮してやはり摺動する。
【００２２】
したがって長期間使用すると、内管１１のセパレート突起１５及び抑え部材１８との当接部が摩耗するが、このような摩耗が生じても、予め間隙１７へ圧入されて内管１１を押圧する抑え部材１８により、内管１１はセパレート突起１５へ押しつけられて接触を維持する。このため、内管１１とセパレート突起１５の間に摩耗間隙が生じず、内管１１の自励的振動を生じさせないので、長期間使用によって生じる可能性があったビビリ音の発生を防止できる。
【００２３】
しかも、セパレート突起１５を外管１０と一体に形成することにより、セパレート突起１５を簡単に形成できる。また、セパレート突起１５の形成により生じた間隙１７へ１個の抑え部材１８を圧入するだけの簡単な構造でビビリ音の防止が可能になる。
【００２４】
そのうえ、抑え部材１８をプラグ溶接で外管１０へ固定するため、抑え部材１８は軽圧入で足りることになり、組立作業が容易になる。しかも、抑え部材１８を外管１０側へプラグ溶接することにより確実に位置決めでき、特別な後加工をしなくても、外管１０をジョイントパイプ１３の内側へ嵌合でき、かつ内管１１との摺動面に溶接痕が残らないので、内管１１の摺動を確保するために抑え部材１８の摺動面に対して特別な仕上げ加工を施す必要もない。
【００２５】
図７は第２実施例に係る図３と同様部位を示す図である。この例では、セパレート突起１５を周方向へ等間隔で３個形成してあり、その結果、同様に３個形成された間隙１７・・のうちの一つに抑え部材１８を圧入してある。抑え部材１８の構造及び固定構造は前実施例と同様である（溶接部の図示を省略）。なお、前実施例と共通部分は共通符号を用いる。以下の実施例も同様である。
【００２６】
図８は第３実施例に係り、外管１０及び内管１１は第１実施例（図３）と同じであるが、この例では隣り合う２つの間隙１７、１７に抑え部材１８、１８を圧入してある。このようにすれば、内管１１をその中心を挟んで抑え部材１８、１８の反対側に位置するセパレート突起１５、１５へより強く押しつけることができる。
【００２７】
図９は第４実施例であり、この例では外管１０の中心を挟んだ対向位置へ１８０°間隔で２個のセパレート突起１５を形成してある。但し、このセパレート突起１５は半径方向内方へ突出するよう湾曲して内管１１の内径Ｒ１１よりも内方へ突出し、かつこれに対応する内管１１の部分もその内径Ｒ１１よりも内方へ凹入する湾曲部２１として形成され、セパレート突起１５と湾曲部２１が密着している。
【００２８】
外方突部１６及び間隙１７はセパレート突起１５と９０°違う位置にやはり１８０°間隔で一対をなして対向配置され、それぞれの間隙１７、１７に抑え部材１８、１８が圧入されている。Ｒ１０は外管１０の外径であり、セパレート突起１５を形成した後端部以外ではこれまでの例と同様に内管１１が外管１０の内側へ所定間隔で同心配置されている。
【００２９】
このようにすると、セパレート突起１５と湾曲部２１において、外管１０と内管１１の密着を良好にできるとともに、長期間の使用によっても、対向配置された抑え部材１８、１８により、対向配置されたセパレート突起１５、１５と湾曲部２１、２１はそれぞれ密着を保たれるため、前各実施例同様にビビリ音を防止できる。
【００３０】
なお、本願発明は上記実施例に限定されず、同一の発明原理内において種々に変形や応用が可能である。例えば、排気管の用途は自動２輪車に限らず、自動車やその他のエンジンに適用できる。抑え部材１８の使用個数は１以上であれば制限されず、上記各実施例に示したように間隙１７の全部又はその一部へ圧入できる。また、その材質は金属に限らずある程度の硬さと耐久性及び耐熱性を備えるものであれば使用可能である。圧入の程度は、直接手で押し込む場合やハンマーのような手動工具による軽圧入から動力装置による大きな圧力による圧入まで種々のものを含む。さらに、抑え部材１８を内管１１に対して固定してもよく、固定方法も溶接に限定されない。
【００３１】
また、セパレート突起１５の形成は外管１０側に限定されず、内管１１側に設けてもよい。またセパレート突起１５を外管１０及び内管１１と別体に形成してもよい。この場合は外管１０又は内管１１のいずれか側へセパレート突起を固着することが好ましい。
【図面の簡単な説明】
【図１】本願発明の内外二重管式排気管を適用した自動２輪車の側面図
【図２】内外二重管式排気管の側面図
【図３】図２の３−３線断面図
【図４】図３の４−４線に沿う断面図
【図５】抑え部材の溶接部を示す図
【図６】同溶接構造示す拡大断面図
【図７】第２実施例に係る図
【図８】第３実施例に係る図
【図９】第４実施例に係る図
【符号の説明】
１：排気管、２：エンジン、３：マフラー、１０：外管、１１：内管１５：、セパレート突起、１６：外方突部、１７：間隙、１８：抑え部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal / external double-pipe exhaust pipe used for a motorcycle or the like, and more particularly to one that does not generate chatter noise even when used for a long period of time.
[0002]
[Prior art]
The exhaust pipe connecting the engine to the muffler has an inner / outer double pipe structure, and at the rear end, a separate protrusion is formed on the outer pipe to protrude radially inward, and this separate protrusion is brought into contact with the inner pipe. The inner tube is supported so as to maintain a predetermined distance from the outer tube, and the inner tube is slidable to allow relative movement of the inner tube with respect to the outer tube due to elongation due to thermal expansion (hereinafter referred to as thermal elongation). An abutting and supporting device is known (see JP-A-11-303632).
[0003]
[Problems to be solved by the invention]
By the way, even in the above structure, when used for a long time, a minute wear gap due to wear occurs between the separation protrusion and the inner tube, and the inner tube may vibrate due to self-excited vibration due to this wear gap. Accordingly, an object of the present invention is to effectively prevent the occurrence of chatter noise.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, an inner / outer double pipe type exhaust pipe according to the present invention is provided with a plurality of separate projections protruding from one side of the outer pipe or the inner pipe to the other side at a predetermined interval in the circumferential direction. In the inner and outer double-pipe type exhaust pipe that holds the inner pipe at a predetermined interval to the inner side of the outer pipe by the separate protrusion and slidably supports the contact partner side at the contact portion of the separate protrusion,
In the gap formed in the inner and outer pipes, a pressing member for pressing the inner pipe to the separate protrusion is press-fitted.
[0005]
At this time, the separation protrusion may be formed from the outer tube toward the inner tube, and the holding member may be fixed to the outer tube by welding.
[0006]
【The invention's effect】
When a restraining member is press-fitted into the gap between the outer tube and the inner tube, the inner tube is strongly pressed against the separation protrusion by the restraining member. When used in this state for a long time, even if wear occurs between the separation protrusion and the contact partner, the inner tube and the separation protrusion are kept in close contact by pressing the holding member, so the inner pipe does not generate self-excited vibration, As a result, generation of chatter noise can be prevented.
[0007]
At this time, if the restraining member is welded to the outer tube, the restraining member can be reliably positioned and the press fitting of the restraining member can be simplified. In addition, since no welding marks remain on the sliding surface, it is not necessary to perform special finishing on the sliding surface of the restraining member in order to ensure the sliding of the inner tube.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The first embodiment will be described below with reference to the drawings. 1 is a side view of a motorcycle to which an internal / external double pipe type exhaust pipe of this embodiment is applied, FIG. 2 is a side view of an exhaust system apparatus including the internal / external double pipe type exhaust pipe of this embodiment, FIG. 2 is a sectional view taken along line 3-3 in FIG. 2, FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, FIG. 5 is a diagram showing a welded portion of the restraining member, and FIG. .
[0009]
As shown in FIG. 1, the exhaust pipe 1 has an exhaust upstream end (hereinafter referred to as a front end) connected to an exhaust port of the engine 2, and a portion extending from the exhaust pipe 1 extends downward from the front of the engine 2. It extends to the rear of the vehicle body, connects the exhaust downstream end (hereinafter referred to as the rear end) to the muffler 3, leads the exhaust gas of the engine 2 to the muffler 3, and discharges it from here to the rear space of the vehicle Yes.
[0010]
In the figure, reference numeral 4 is a head pipe, 5 is a vehicle body frame, 6 is a pivot shaft, 7 is a rear end that supports a rear wheel (not shown) at the rear end, and is supported at the rear end by a pivot shaft 6 so as to be swingable. A swing arm 8 is a rear cushion unit provided between the vehicle body frame and the rear swing arm.
[0011]
In FIG. 2, the exhaust pipe 1 has an inner / outer double pipe structure of an outer pipe 10 and an inner pipe 11. A flange 12 is provided at the front end of the exhaust pipe 1 and is attached to the exhaust port of the engine 2 here. The rear end of the exhaust pipe 1 is fitted and connected to the joint pipe 13.
[0012]
The joint pipe 13 extends the inside of the muffler 3 to the exhaust downstream side, and guides the exhaust gas into the main body of the muffler 3. A small diameter portion 14 formed on the front end side of the muffler 3 is covered on the connection portion between the exhaust pipe 1 and the joint pipe 13 and is welded to the outer surface of the outer pipe 10 together with the joint pipe 13.
[0013]
As shown in FIGS. 3 and 4, the outer tube 10 and the inner tube 11 each have a round pipe shape made of an appropriate metal such as iron, and the inner tube 11 keeps a predetermined gap D on the inner side of the outer tube 10. In this way, a separate projection 15 for concentrically holding the projection is formed at the rear end of the exhaust pipe 1 so as to project from the outer pipe 10 toward the inner pipe 11.
[0014]
The separation protrusion 15 is formed by integrally forming the rear end portion of the outer tube 10 in the radial direction by press molding so as to be in contact with and supported by the outer periphery of the inner tube 11. Four pieces are formed at equal intervals in the circumferential direction, and the protruding height is substantially the same as the gap D between the outer tube 10 and the inner tube 11. Further, the contact portion of the separate protrusion 15 with respect to the inner tube 11 is slidable in order to enable expansion and contraction due to thermal expansion of the inner tube 11.
[0015]
As is clear from FIG. 4, the outer tube 10 and the inner tube 11 are integrated at the rear end portion with a separate projection 15 portion, but the inner tube 11 is concentrically arranged on the inner side of the outer tube 10 in front of it. The predetermined interval D is maintained.
[0016]
As is apparent from FIG. 3, an outer protrusion 16 that protrudes radially outward from the inner tube 11 side is formed between the adjacent separate protrusions 15 and 15, and a gap 17 is formed inside thereof. The outer protrusion 16 is an expression when the outer tube 10 is viewed from the inner tube 11 side, and is a portion that remains as a non-molded portion when the separation protrusion 15 is formed in the rear end portion of the outer tube 10. Therefore, the outer peripheral portion of the outer protrusion 16 is an original outer diameter portion of the outer tube 10, and the width of the gap 17 in the radial direction is a predetermined distance D.
[0017]
A holding member 18 is press-fitted into one of the gaps 17 and is plug welded to the outward projection 16 by a plug 19. The holding member 18 is made of an appropriate metal material such as iron, and the thickness T thereof is set to be slightly larger than the radial width of the gap 17, that is, a predetermined distance D between the outer tube 10 and the inner tube 11, and is struck with a hammer. It is press-fitted with a light press-fitting to the extent that it is pushed by.
[0018]
As apparent from FIGS. 4 and 6, the end of the holding member 18 that is press-fitted is formed into a thin shape to facilitate press-fitting, such as a round shape or a tapered shape, and a separate protrusion as shown in FIG. 15 has a length slightly shorter than 15 and is bent in an arc shape so as to be in sliding contact with the outer periphery of the inner tube 11 as shown in FIG.
[0019]
FIG. 5 is a view showing the separation protrusion 15 and the holding member 18 of the outer tube 10 from the direction indicated by the arrow Y in FIG. 4, and the holding member 18 is formed on the outer protrusion 16 which is the rear end portion of the outer tube 10. It is plug welded to the outer tube 10 through the plug 19 inserted into the through hole 20. 6A is a cross-sectional view taken along line 6-6 in FIG. 5 schematically showing the welded structure.
[0020]
Note that the fixing of the holding member 18 is not limited to plug welding, and other appropriate welding methods are possible. In FIG. 6B, fillets are welded between the end faces of the holding member 18 and the outer tube 10. Even in this case, there is no problem as long as the weld bead does not reach the inner tube 11, and the holding member 18 and the inner tube 11 can slide.
[0021]
Next, the operation of this embodiment will be described. As shown in FIG. 3, by pressing the holding member 18 into the gap 17, the inner tube 11 is pressed against the separate projection 15 on the opposite side with some elastic deformation. In this state, when the inner tube 11 extends relative to the outer tube 10 due to thermal expansion, the inner tube 11 slides with respect to the separation protrusion 15 and the holding member 18, and when cooled, the inner tube 11 contracts and slides.
[0022]
Accordingly, when used for a long period of time, the contact portion of the inner tube 11 with the separation protrusion 15 and the restraining member 18 wears out. Even if such wear occurs, the inner tube 11 is pressed into the gap 17 and pressed against the inner tube 11 in advance. The inner tube 11 is pressed against the separation protrusion 15 by the member 18 to maintain contact. For this reason, no wear gap is generated between the inner tube 11 and the separation protrusion 15, and self-excited vibration of the inner tube 11 is not generated, so that it is possible to prevent the occurrence of chatter noise that may occur due to long-term use.
[0023]
In addition, by forming the separation protrusion 15 integrally with the outer tube 10, the separation protrusion 15 can be easily formed. In addition, chattering noise can be prevented with a simple structure in which one holding member 18 is press-fitted into the gap 17 generated by the formation of the separation protrusion 15.
[0024]
In addition, since the holding member 18 is fixed to the outer tube 10 by plug welding, the holding member 18 needs only to be lightly press-fitted, and the assembling work is facilitated. Moreover, the holding member 18 can be reliably positioned by plug welding to the outer tube 10 side, the outer tube 10 can be fitted inside the joint pipe 13 without any special post-processing, and the inner tube 11 Therefore, it is not necessary to perform a special finishing process on the sliding surface of the holding member 18 in order to ensure the sliding of the inner tube 11.
[0025]
FIG. 7 is a view showing the same parts as FIG. 3 according to the second embodiment. In this example, three separate projections 15 are formed at equal intervals in the circumferential direction, and as a result, the restraining member 18 is press-fitted into one of the three gaps 17. The structure and fixing structure of the holding member 18 are the same as in the previous embodiment (the illustration of the welded portion is omitted). In addition, a common code | symbol is used for a common part with a previous Example. The same applies to the following embodiments.
[0026]
FIG. 8 relates to the third embodiment, and the outer tube 10 and the inner tube 11 are the same as in the first embodiment (FIG. 3), but in this example, the holding members 18, 18 are provided in the two adjacent gaps 17, 17. It is press-fitted. In this way, the inner tube 11 can be pressed more strongly against the separate protrusions 15 and 15 located on the opposite side of the holding members 18 and 18 with the center therebetween.
[0027]
FIG. 9 shows a fourth embodiment. In this example, two separate projections 15 are formed at 180 ° intervals at opposing positions sandwiching the center of the outer tube 10. However, the separate protrusion 15 is curved so as to protrude inward in the radial direction and protrudes inward from the inner diameter R11 of the inner tube 11, and the corresponding portion of the inner tube 11 is also inward from the inner diameter R11. It is formed as a concave curved portion 21, and the separation protrusion 15 and the curved portion 21 are in close contact with each other.
[0028]
The outer protrusion 16 and the gap 17 are arranged opposite to each other at a position different by 90 ° from the separate protrusion 15 at an interval of 180 °, and holding members 18 and 18 are press-fitted into the gaps 17 and 17, respectively. R10 is the outer diameter of the outer tube 10, and the inner tube 11 is concentrically arranged inside the outer tube 10 at a predetermined interval in the same manner as in the previous examples except for the rear end portion where the separation protrusion 15 is formed.
[0029]
In this way, the separation protrusion 15 and the bending portion 21 can be made to adhere well between the outer tube 10 and the inner tube 11 and are opposed to each other by the restraining members 18 and 18 that are opposed to each other even after long-term use. Since the separate protrusions 15 and 15 and the curved portions 21 and 21 are kept in close contact with each other, chatter noise can be prevented as in the previous embodiments.
[0030]
The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the same inventive principle. For example, the use of the exhaust pipe is not limited to motorcycles but can be applied to automobiles and other engines. The number of use of the restraining member 18 is not limited as long as it is 1 or more, and can be press-fitted into all or a part of the gap 17 as shown in the above embodiments. The material is not limited to metal, and any material having a certain degree of hardness, durability, and heat resistance can be used. The degree of press-fitting includes various cases from direct press-in by hand or light press-fitting with a manual tool such as a hammer to press-fitting with a large pressure by a power unit. Further, the holding member 18 may be fixed to the inner tube 11, and the fixing method is not limited to welding.
[0031]
Further, the formation of the separation protrusion 15 is not limited to the outer tube 10 side, and may be provided on the inner tube 11 side. Further, the separation protrusion 15 may be formed separately from the outer tube 10 and the inner tube 11. In this case, it is preferable that the separation protrusion is fixed to either the outer tube 10 or the inner tube 11.
[Brief description of the drawings]
FIG. 1 is a side view of a motorcycle to which an inner and outer double pipe exhaust pipe of the present invention is applied. FIG. 2 is a side view of an inner and outer double pipe exhaust pipe. 4 is a cross-sectional view taken along line 4-4 in FIG. 3. FIG. 5 is a view showing a welded portion of a restraining member. FIG. 6 is an enlarged cross-sectional view showing the weld structure. FIG. 8 is a diagram according to a third embodiment. FIG. 9 is a diagram according to a fourth embodiment.
1: exhaust pipe, 2: engine, 3: muffler, 10: outer pipe, 11: inner pipe 15: separate projection, 16: outward projection, 17: gap, 18: restraining member

Claims

It has an inner / outer double pipe structure, and a plurality of separate projections projecting from one side of the outer tube or the inner tube to contact the other are provided at predetermined intervals in the circumferential direction, and the inner tube is brought into the inner side of the outer tube by the separate projections In the inner and outer double-pipe type exhaust pipe that is held at a predetermined interval and that slidably supports the abutting counterpart side at the abutting portion of the separate protrusion,
An internal / external double-pipe type exhaust pipe, wherein a pressing member for pressing the inner pipe into the separation protrusion is press-fitted into a gap formed in the inner / outer pipe.

The inner / outer double pipe exhaust pipe according to claim 1, wherein the separation protrusion is formed from the outer pipe toward the inner pipe, and the holding member is fixed to the outer pipe by welding.