JPH0544507Y2 - - Google Patents
Info
- Publication number
- JPH0544507Y2 JPH0544507Y2 JP14175788U JP14175788U JPH0544507Y2 JP H0544507 Y2 JPH0544507 Y2 JP H0544507Y2 JP 14175788 U JP14175788 U JP 14175788U JP 14175788 U JP14175788 U JP 14175788U JP H0544507 Y2 JPH0544507 Y2 JP H0544507Y2
- Authority
- JP
- Japan
- Prior art keywords
- branch pipe
- pipe
- exhaust port
- exhaust
- bending direction
- 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.)
- Expired - Lifetime
Links
- 238000005452 bending Methods 0.000 claims description 36
- 238000011144 upstream manufacturing Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229910001018 Cast iron Inorganic materials 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Landscapes
- Exhaust Silencers (AREA)
Description
【考案の詳細な説明】
（産業上の利用分野）
本考案は、エンジンの排気マニホールドに関
し、特に、エンジン外への開口が断面楕円状に形
成された排気ポートに接続されるものに関する。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an exhaust manifold for an engine, and particularly to one in which an opening to the outside of the engine is connected to an exhaust port having an elliptical cross section.
（従来の技術）
一般に、エンジンの排気マニホールドは鋳鉄等
により形成されているが、この鋳鉄は重く、エン
ジンの軽量化の点で難がある。(Prior Art) Generally, the exhaust manifold of an engine is made of cast iron or the like, but cast iron is heavy and there are difficulties in reducing the weight of the engine.
このことから、従来、例えば実開昭60−3226号
公報に開示されるものには、排気マニホールドを
ステンレス鋼等の耐熱性、耐蝕性を有するパイプ
部材を折曲げ加工して製作することが提案されて
いる。 For this reason, it has been proposed in the past, for example, in what is disclosed in Japanese Utility Model Application Publication No. 60-3226, to manufacture the exhaust manifold by bending a pipe member having heat resistance and corrosion resistance such as stainless steel. has been done.
（考案が解決しようとする課題）
ところで、例えば各気筒に複数の排気弁を有す
る多気筒エンジンでは、排気抵抗を小さくする等
の目的から、上流端が各排気弁に連通する排気ポ
ートを途中で合流させ、その合流した排気ポート
の下流端開口部（エンジン外への開口部）を楕円
状に形成することが行われる。(Problem to be solved by the invention) By the way, for example, in a multi-cylinder engine in which each cylinder has a plurality of exhaust valves, for the purpose of reducing exhaust resistance, the exhaust port whose upstream end communicates with each exhaust valve is connected midway. The downstream end openings (openings to the outside of the engine) of the merged exhaust ports are formed into an elliptical shape.
このため、この排気ポートの楕円状開口に、上
記従来の如くパイプからなる排気マニホールドの
分岐管を接続する場合、該分岐管の接続端部は排
気ポート形状に対応して断面楕円状に拡管加工す
る必要がある。 Therefore, when connecting a branch pipe of an exhaust manifold consisting of a pipe as in the above-mentioned conventional pipe to the elliptical opening of this exhaust port, the connecting end of the branch pipe is expanded to an elliptical cross-section to correspond to the shape of the exhaust port. There is a need to.
しかし、その場合、多気筒エンジンでは、複数
の分岐管がまとめられて１本の排気管に集合され
る関係上、各分岐管は彎曲しており、特にエンジ
ンの気筒列方向端部の気筒に対応する分岐管の曲
率半径は小さい。このため、分岐管の排気ポート
への接続端部は、彎曲のための折曲げ加工に加
え、楕円状開口部のために拡管加工されることと
なり、その曲り方向外側の肉厚が内側よりも薄く
なる。しかも、この曲り方向外側部分は排気ポー
トから吐出される高温の排気ガスが直接当たり易
い部分であり、その熱負荷は大きい。その結果、
その薄くなつた分岐管の外側部にクラツクが発生
する虞れがある。 However, in this case, in a multi-cylinder engine, each branch pipe is curved because the multiple branch pipes are gathered together into one exhaust pipe, and the cylinders at the end of the engine cylinder row are particularly The radius of curvature of the corresponding branch pipe is small. For this reason, the connecting end of the branch pipe to the exhaust port is not only bent for curving, but also expanded for the elliptical opening, and the wall thickness on the outside in the bending direction is thicker than on the inside. Become thin. Furthermore, this outer portion in the bending direction is a portion that is likely to be directly hit by high-temperature exhaust gas discharged from the exhaust port, and the heat load thereon is large. the result,
There is a risk that cracks may occur on the outer side of the thinned branch pipe.
また、分岐管の接続端部は拡管加工によつて断
面形状が略段差状に大きく変化することから、そ
の段差部が分岐管の曲り方向外側にあると、その
段差部に排気ポートから出た排気ガスが直接当た
つて、その流れが活流により阻害されることとな
り、排気抵抗が増大するという問題も生じる。 In addition, because the cross-sectional shape of the connecting end of the branch pipe changes significantly due to pipe expansion into an almost step-like shape, if the step is on the outside in the bending direction of the branch pipe, the exhaust port exits from the step. When the exhaust gas hits directly, its flow is obstructed by the active current, which also causes the problem of increased exhaust resistance.
本考案は斯かる諸点に鑑みてなされたものであ
り、その目的は、上記の如くパイプからなる排気
マニホールドの分岐管の排気ポートへの接続端部
の構造を特定することにより、分岐管接続端部の
拡管加工に伴う曲り方向外側の薄肉化を防いで、
その曲り方向内外の肉厚を同等にするとともに、
その曲り方向外側での段差部をなくして排気抵抗
を低減することにある。 The present invention has been made in view of the above points, and its purpose is to identify the structure of the connection end of the branch pipe of the exhaust manifold made of pipes to the exhaust port, and to improve the connection end of the branch pipe to the exhaust port. This prevents the thinning of the outer wall in the bending direction due to the tube expansion process.
In addition to making the wall thickness on the inside and outside in the bending direction the same,
The objective is to reduce exhaust resistance by eliminating the stepped portion on the outside in the bending direction.
（課題を解決するための手段）
上記目的を達成するために、本考案の解決手段
は、エンジン外への開口が楕円状に形成された排
気ポートに接続される排気マニホールドを、折曲
げ加工された彎曲状のパイプからなる分岐管を有
するものとし、この分岐管の排気ポートへの接続
端部を排気ポートの開口形状に対応して断面楕円
状に形成する。(Means for Solving the Problem) In order to achieve the above object, the solution of the present invention is to bend an exhaust manifold connected to an exhaust port having an elliptical opening to the outside of the engine. The branch pipe is made of a curved pipe, and the connecting end of the branch pipe to the exhaust port is formed to have an elliptical cross section corresponding to the opening shape of the exhaust port.
そして、その場合、上記分岐管の接続端部の楕
円状開口部の中心を分岐管本来の中心線よりも分
岐管の曲り方向内側にオフセツトさせて、その接
続端部に分岐管の曲り方向内側に膨出する膨出部
を形成する。 In that case, the center of the elliptical opening at the connecting end of the branch pipe is offset inward in the bending direction of the branch pipe from the original center line of the branch pipe, so that the connecting end is placed inward in the bending direction of the branch pipe. Forms a bulge that bulges out.
（作用）
上記の構成により、本考案では、排気マニホー
ルドのパイプからなる分岐管の排気ポートへの接
続端部の楕円状開口部中心が分岐管の中心線より
も分岐管の曲り方向内側にオフセツトされて、そ
の接続端部が分岐管の曲り方向内側に膨出してい
る構造であるので、パイプの曲げ加工後にその接
続端部を拡管加工するのに伴い、その接続端部の
曲り方向内側部のみが変形して肉厚が小さくなる
が、外側部は全く変形せずに曲げ加工後と同じ肉
厚に保たれる。このことにより、分岐管端部の曲
り方向外側の肉厚が極度に薄くなるのが抑えら
れ、熱負荷に対しても十分耐え得る厚さとなり、
よつてその外側部のクラツクの発生等を有効に防
止できる。(Function) With the above configuration, in the present invention, the center of the elliptical opening at the connection end to the exhaust port of the branch pipe consisting of the pipe of the exhaust manifold is offset inward in the bending direction of the branch pipe from the center line of the branch pipe. Since the connecting end bulges inward in the bending direction of the branch pipe, when the connecting end is expanded after bending the pipe, the inner part of the connecting end in the bending direction Only the outer part is deformed and the thickness becomes smaller, but the outer part is not deformed at all and remains the same thickness as after bending. This prevents the wall thickness on the outside in the bending direction of the end of the branch pipe from becoming extremely thin, making it thick enough to withstand thermal loads.
Therefore, the occurrence of cracks on the outer side can be effectively prevented.
また、分岐管の接続端部が分岐管の曲り方向内
側に膨出していることから、外側には段差部がな
くなり、排気ポートから出た排気ガスの流れが段
差部によつて阻害されることはなく、よつて排気
抵抗を低減することができる。 In addition, since the connecting end of the branch pipe bulges inward in the bending direction of the branch pipe, there is no step on the outside, and the flow of exhaust gas coming out of the exhaust port is obstructed by the step. Therefore, the exhaust resistance can be reduced.
（実施例）
以下、本考案の実施例を図面に基づいて説明す
る。(Example) Hereinafter, an example of the present invention will be described based on the drawings.
第２図及び第３図において、１は直列に配置さ
れた第１〜第４の４つの気筒（図示せず）を有す
る４バルブ式の４気筒エンジンであつて、このエ
ンジン１のシリンダヘツド２には吸気ポート（図
示せず）及び排気ポート３が形成され、上記吸気
ポートは二股状に分岐されてその下流端が各気筒
内燃焼室に開口している。一方、排気ポート３の
上流端は二股状に分岐されて各気筒に連通し、そ
の下流端はシリンダヘツド２の一側面に水平左右
方向を長径方向とする断面楕円状となつて開口し
ている。 In FIGS. 2 and 3, reference numeral 1 denotes a 4-valve type 4-cylinder engine having four cylinders (not shown) arranged in series, cylinder head 2. An intake port (not shown) and an exhaust port 3 are formed in the cylinder, and the intake port is bifurcated, with its downstream end opening into the combustion chamber in each cylinder. On the other hand, the upstream end of the exhaust port 3 is bifurcated and communicates with each cylinder, and the downstream end thereof is opened on one side of the cylinder head 2 with an elliptical cross-section whose major diameter is in the horizontal left-right direction. .
４は本考案の実施例に係る排気マニホールドで
あつて、この排気マニホールド４は、上記シリン
ダヘツド２の一側面にガスケツト（図示せず）を
介して気密状に取り付けられるフランジ５と、
各々上端（上流端）が該フランジ５に接合固定さ
れた鋼製のパイプからなる第１〜第４の４つの分
岐管６〜９と、該分岐管６〜９の下端（下流端）
に接合されて固定された集合部材１３とを備えて
なる。上記集合部材１３は、上方に向けてテーパ
状に拡がつた集合管部１３ａと、該集合管部１３
ａの下端小径部に一体形成され、締結ボルト１３
ｃ，１３ｃ，…を有する締結フランジ部１３ｂと
からなる。上記各分岐管６〜９は第４図〜第６図
に示すようにその下端が断面円形状から円の四半
部を占める断面扇形状に徐々に変形しており、そ
の端部は束状に重合されて上記集合部材１３の集
合管部１３ａ内に嵌合されかつ溶接により気密状
に固定されている。 4 is an exhaust manifold according to an embodiment of the present invention, and this exhaust manifold 4 includes a flange 5 airtightly attached to one side of the cylinder head 2 via a gasket (not shown);
Four first to fourth branch pipes 6 to 9 made of steel pipes whose upper ends (upstream ends) are fixed to the flange 5, and lower ends (downstream ends) of the branch pipes 6 to 9.
and an assembly member 13 joined and fixed to the assembly member 13. The collecting member 13 includes a collecting pipe portion 13a that tapers upwardly, and a collecting pipe portion 13a that tapers upwardly.
The fastening bolt 13 is integrally formed on the small diameter portion of the lower end of
c, 13c, . . . As shown in FIGS. 4 to 6, each of the branch pipes 6 to 9 has its lower end gradually deformed from a circular cross-section to a fan-shaped cross-section occupying a quarter of a circle, and the end thereof is shaped like a bundle. They are superimposed and fitted into the collecting pipe portion 13a of the collecting member 13, and are fixed in an airtight manner by welding.
また、上記フランジ５には上記各排気ポート３
の開口３ａと同じ楕円状の開口５ａが排気ポート
３位置に対応して形成され、この開口５ａに上記
各分岐管６〜９の一端が嵌合されて溶接により気
密状に固定されている。よつて、上記各分岐管６
〜９は上記集合部材１３への集合のために折曲げ
加工されて彎曲しており、特に、エンジン１の第
１及び第４気筒に対応する第１及び第４分岐管
６，９はその上端つまり排気ポート３への接続端
部の近傍で小さな曲率半径で折り曲げられてい
る。また、各分岐管６〜９の排気ポート３への接
続端部は上記フランジ５の開口５ａに嵌合可能に
排気ポート３の開口３ａの形状に対応して断面楕
円状に形成されている。 In addition, each of the exhaust ports 3 is attached to the flange 5.
An elliptical opening 5a, which is the same as the opening 3a, is formed corresponding to the position of the exhaust port 3, and one end of each of the branch pipes 6 to 9 is fitted into this opening 5a and fixed in an airtight manner by welding. Therefore, each of the above branch pipes 6
9 are bent and curved in order to assemble into the aggregation member 13, and in particular, the first and fourth branch pipes 6 and 9 corresponding to the first and fourth cylinders of the engine 1 are at their upper ends. That is, it is bent with a small radius of curvature near the end connected to the exhaust port 3. Further, the connecting end of each of the branch pipes 6 to 9 to the exhaust port 3 is formed to have an elliptical cross section corresponding to the shape of the opening 3a of the exhaust port 3 so as to be able to fit into the opening 5a of the flange 5.
そして、本考案の特徴として、上記第１分岐管
６のシリンダヘツド２への接続端部は、第１図に
示すように、その楕円状開口部の中心O2が分岐
管６本来の中心線O1に対し分岐管６の曲り方向
内側（第４分岐管９側）にオフセツトされてい
て、該接続端部には分岐管６の曲り方向内側に膨
出する膨出部６ａが形成されている。また、上記
と同様に、第４分岐管９のシリンダヘツド２への
接続端部もその楕円状開口部の中心が分岐管９の
中心線よりも分岐管９の曲り方向内側（第１分岐
管６側）にオフセツトされていて、該接続端部に
は同様に膨出する膨出部９ａが形成されている。 As a feature of the present invention, as shown in FIG . O 1 is offset to the inside in the bending direction of the branch pipe 6 (on the fourth branch pipe 9 side), and a bulging part 6a that bulges inward in the bending direction of the branch pipe 6 is formed at the connecting end. There is. Similarly to the above, the center of the elliptical opening of the connecting end of the fourth branch pipe 9 to the cylinder head 2 is located inside the center line of the branch pipe 9 in the bending direction of the branch pipe 9 (the first branch pipe 6 side), and a similarly bulging bulge 9a is formed at the connecting end.
尚、第２及び第３分岐管７，８のシリンダヘツ
ド２への接続端部は楕円状開口部の中心が分岐管
７，８の中心線と略一致していて、該分岐管７，
８の左右両側に略同じ寸法だけ膨出している。 Note that the centers of the elliptical openings of the connecting ends of the second and third branch pipes 7 and 8 to the cylinder head 2 substantially coincide with the center lines of the branch pipes 7 and 8.
It protrudes by approximately the same size on both the left and right sides of 8.
ここで、上記第１又は第４分岐管６，９を製造
する場合、例えば第７図に示すように、先ず、図
ａに示す如き直線状のパイプ１４を所定の曲率半
径で折曲げ加工して、図ｂに示す如く曲管とす
る。次いで、図ｃに示す如く、そのパイプ１４の
エンジン１への接続端部となる一端に、断面楕円
状の先細りテーパ状の拡管用治具１５をその中心
O3がパイプ１４の中心O1からその曲り方向内側
にオフセツトさせた状態で嵌入してそれを加圧す
ることにより、バイプ１４の接続端部を拡管して
膨出させればよい。 Here, when manufacturing the first or fourth branch pipes 6, 9, as shown in FIG. 7, first, a straight pipe 14 as shown in FIG. a is bent at a predetermined radius of curvature. Then, form a curved pipe as shown in Figure b. Next, as shown in FIG.
The connecting end of the pipe 14 may be expanded and bulged by inserting O 3 into the pipe 14 while being offset inward in the bending direction from the center O 1 and pressurizing it.
したがつて、上記実施例においては、排気マニ
ホールド４の第１及び第４分岐管６，９の対応す
る排気ポート３への接続端部の楕円状開口部の中
心O2が分岐管６，９の中心線O1よりも分岐管６，
９の曲り方向内側にオフセツトされて、その接続
端部が分岐管６，９の曲り方向内側に膨出してい
るので、分岐管６，９となるパイプ１４の接続端
部を曲げ加工後に拡管加工する際（第７図ｃ参
照）、その接続端部の曲り方向内側部（同図で右
側）のみが変形して肉厚が小さくなるが、外側部
（同左側）は全く変形せずに曲げ加工後と同じ肉
厚に保たれることとなる。このことにより、分岐
管６，９端部の曲り方向外側の肉厚が極度に薄く
なるのを抑えることができ、排気ガスによる熱負
荷に対しても十分耐え得るようにすることがで
き、よつてその外側部のクラツクの発生等を有効
に防止することができる。 Therefore, in the above embodiment, the center O 2 of the elliptical opening of the connecting end of the first and fourth branch pipes 6 and 9 of the exhaust manifold 4 to the corresponding exhaust port 3 is located at the center O 2 of the elliptical opening of the first and fourth branch pipes 6 and 9 of the exhaust manifold 4. Branch pipe 6, than the center line O 1 of
9 is offset inward in the bending direction of the pipe 14, and its connecting end bulges inward in the bending direction of the branch pipes 6 and 9. Therefore, the connecting end of the pipe 14, which will become the branch pipe 6 and 9, is bent and then expanded. When bending (see Figure 7c), only the inner part (on the right side in the figure) of the connecting end in the bending direction deforms and the wall thickness becomes smaller, but the outer part (on the left side in the same figure) does not deform at all and bends. The wall thickness will remain the same as after processing. By doing this, it is possible to prevent the wall thickness of the ends of the branch pipes 6 and 9 on the outside in the bending direction from becoming extremely thin, and it is possible to sufficiently withstand the heat load caused by the exhaust gas. This makes it possible to effectively prevent the occurrence of cracks on the outer side.
また、これら分岐管６，９の接続端部は分岐管
６，９の曲り方向内側に膨出していて、外側には
段差部がなくなる。このため、排気ポート３から
出た排気ガスの流れが段差部により阻害されて活
流が生じることはなく、よつて排気抵抗を低減す
ることができる。 Further, the connection ends of these branch pipes 6 and 9 bulge inward in the bending direction of the branch pipes 6 and 9, and there is no stepped portion on the outside. Therefore, the flow of exhaust gas exiting from the exhaust port 3 is not obstructed by the stepped portion and active flow is not generated, thereby reducing exhaust resistance.
しかも、上記各分岐管６〜９はその下流側で
徐々に断面円形状から断面扇形状に変形し、その
端部は束状に重合されて集合部材１３の集合管部
１３ａ内に嵌合固定されているので、各分岐管６
〜９の下流端部における断面形状が滑らかに変化
し、集合部材１３における排気ガスの活流の発生
を抑制して排気抵抗を低減することができる。よ
つて、このような排気抵抗の低減によりエンジン
出力を向上させることができる。 Furthermore, each of the branch pipes 6 to 9 gradually deforms from a circular cross-section to a fan-shaped cross-section on the downstream side thereof, and the ends thereof are overlapped into a bundle and fixedly fitted into the collecting pipe portion 13a of the collecting member 13. Since each branch pipe 6
The cross-sectional shape at the downstream end of the points 1 to 9 changes smoothly, suppressing the generation of active flow of exhaust gas in the gathering member 13, and reducing exhaust resistance. Therefore, engine output can be improved by reducing exhaust resistance in this manner.
また、各分岐管６〜９の下流端部は断面扇形状
とされて集合部材１３の集合管部１３ａ内に嵌合
固定されているので、該集合管部１３ａを断面円
形状として、その加工を容易化することができる
とともに、信頼性を向上させることができる。 Further, since the downstream end of each of the branch pipes 6 to 9 has a fan-shaped cross section and is fitted and fixed in the collecting pipe part 13a of the collecting member 13, the collecting pipe part 13a has a circular cross section and its processing It is possible to facilitate the process and improve reliability.
第８図〜第１０図は本考案をＶ型６気筒エンジ
ン用の排気マニホールドに適用した実施例を示
す。尚、この実施例では第１図、第２図及び第６
図と同じ部分については同じ符号を付してその詳
細な説明は省略する。 8 to 10 show an embodiment in which the present invention is applied to an exhaust manifold for a V-type six-cylinder engine. In addition, in this embodiment, FIGS. 1, 2, and 6
The same parts as those in the figures are given the same reference numerals, and detailed explanation thereof will be omitted.
すなわち、この実施例では、第１〜第６の６つ
の気筒（図示せず）を有するＶ型６気筒エンジン
１′において、その各バンクにおけるシリンダヘ
ツド２′には排気ポート３が形成され、該排気ポ
ート３の上流端は２つに分岐されて各気筒に連通
され、下流端は各シリンダヘツド２′の相対する
バンクと反対側側面に断面楕円状となつて開口さ
れている。尚、図では第１気筒、第３気筒及び第
５気筒が形成された一方のバンクを示す。 That is, in this embodiment, in a V-type six-cylinder engine 1' having six first to sixth cylinders (not shown), an exhaust port 3 is formed in the cylinder head 2' of each bank. The upstream end of the exhaust port 3 is branched into two and communicates with each cylinder, and the downstream end has an elliptical cross-section and is opened on the opposite side of the opposite bank of each cylinder head 2'. In addition, the figure shows one bank in which the first cylinder, the third cylinder, and the fifth cylinder are formed.
上記各バンクの各排気ポート３には排気マニホ
ールド４′が連通され、このマニホールド４′はパ
イプからなる３つの分岐管１０〜１２を有し、該
分岐管１０〜１２は排気ポート３への接続端部が
断面楕円状に形成されている。そして、そのう
ち、第１気筒及び第５気筒に対応する分岐管１
０，１２は、その接続端部近傍で折曲げ加工され
ており、かつ該排気ポート３への接続端部は、そ
の楕円状開口部の中心が分岐管１０，１２の中心
線よりも分岐管１０，１２の曲り方向内側にオフ
セツトされていて、接続端部には分岐管１０，１
２の曲り方向内側に膨出する膨出部１０ａ，１２
ａが形成されている。尚、３つの分岐管１０〜１
２の下流端は円の三半部を占める断面楕円状に形
成されて集合部材１３′の集合管部１３a′に嵌合
固定されている。したがつて、この実施例でも上
記実施例と同様の作用効果を奏することができ
る。 An exhaust manifold 4' is connected to each exhaust port 3 of each bank, and this manifold 4' has three branch pipes 10 to 12 made of pipes, and the branch pipes 10 to 12 are connected to the exhaust port 3. The end portion is formed into an elliptical cross section. Among them, branch pipe 1 corresponding to the first cylinder and the fifth cylinder
0 and 12 are bent near their connecting ends, and at the connecting ends to the exhaust port 3, the center of the elliptical opening is closer to the branch pipe than the center line of the branch pipes 10 and 12. The branch pipes 10 and 12 are offset inward in the bending direction, and the branch pipes 10 and 12 are connected at the connecting end.
The bulging portions 10a and 12 bulge inward in the bending direction of 2.
a is formed. In addition, three branch pipes 10 to 1
The downstream end of the tube 2 is formed into an elliptical cross section occupying three halves of a circle, and is fitted and fixed to the collecting pipe portion 13a' of the collecting member 13'. Therefore, this embodiment can also provide the same effects as those of the above embodiment.
（考案の効果）
以上の如く、本考案の排気マニホールドによる
と、折曲げ加工された彎曲状のパイプからなる分
岐管の排気ポートへの接続端部が排気ポートの開
口形状に対応して断面楕円状に形成され、その接
続端部はその楕円状開口部の中心が分岐管本来の
中心線よりも分岐管の曲り方向内側にオフセツト
されて、分岐管の曲り方向内側に膨出されている
ものであるので、パイプの曲げ加工後にその接続
端部を断面楕円状に拡管加工する際に、接続端部
の曲り方向外側部を変形させずとも済み、分岐管
端部の曲り方向側の肉厚が内側に比べて極度に薄
くなるのを抑えて、その外側部のクラツクの発生
等を有効に防止できるとともに、分岐管の接続端
部における曲り方向外側の段差部をなくし、排気
抵抗を低減してエンジン出力の向上を図ることが
できるという実用上優れた効果を有する。(Effect of the invention) As described above, according to the exhaust manifold of the invention, the connecting end of the branch pipe made of a bent curved pipe to the exhaust port has an elliptical cross section corresponding to the opening shape of the exhaust port. The connection end is bulged inward in the bending direction of the branch pipe, with the center of the elliptical opening offset inward in the bending direction of the branch pipe from the original center line of the branch pipe. Therefore, when expanding the connecting end into an elliptical cross-section after bending the pipe, there is no need to deform the outer part of the connecting end in the bending direction, and the wall thickness of the branch pipe end on the bending direction side can be reduced. This prevents the pipe from becoming extremely thin compared to the inside, effectively preventing the occurrence of cracks on the outside, and also eliminates the step on the outside in the bending direction at the connecting end of the branch pipe, reducing exhaust resistance. This has an excellent practical effect in that it is possible to improve the engine output.
第１図〜第７図は本考案の一実施例を示し、第
１図は第３図の−線断面図、第２図は排気マ
ニホールドの平面図、第３図は同正面図、第４図
は第３図の−線断面図、第５図は同−線
断面図、第６図は同−線断面図、第７図は分
岐管の製造工程を概略的に示す工程図である。第
８図〜第１０図は他の実施例を示し、第８図は第
３図相当図、第９図は側面図、第１０図は第９図
の−線断面図である。
１，１′……エンジン、３……排気ポート、３
ａ……開口、４，４′……排気マニホールド、６
〜１２……分岐管、６ａ，９ａ，１０ａ，１２ａ
……膨出部、O1……分岐管中心線、O2……分岐
管の楕円開口の中心。
1 to 7 show one embodiment of the present invention, in which FIG. 1 is a sectional view taken along the line - - in FIG. 3, FIG. 2 is a plan view of the exhaust manifold, FIG. 3 is a front view of the same, and FIG. The drawings are a cross-sectional view taken along the line -- in FIG. 3, FIG. 5 is a cross-sectional view taken along the same line, FIG. 6 is a cross-sectional view taken along the same line, and FIG. 7 is a process diagram schematically showing the manufacturing process of the branch pipe. 8 to 10 show other embodiments, where FIG. 8 is a view corresponding to FIG. 3, FIG. 9 is a side view, and FIG. 10 is a sectional view taken along the line -- in FIG. 9. 1,1'...Engine, 3...Exhaust port, 3
a...Opening, 4, 4'...Exhaust manifold, 6
~12...Branch pipe, 6a, 9a, 10a, 12a
...Bulge, O 1 ... Branch pipe center line, O 2 ... Center of the elliptical opening of the branch pipe.
Claims (1)
た排気ポートに接続される排気マニホールドであ
つて、折曲げ加工された彎曲状のパイプからなる
分岐管を有し、該分岐管の排気ポートへの接続端
部が排気ポートの開口形状に対応して断面楕円状
に形成されており、かつ該分岐管の接続端部はそ
の楕円状開口部の中心が分岐管の中心線に対し分
岐管の曲り方向内側にオフセツトされていて、分
岐管の曲り方向内側に膨出する膨出部を有してい
ることを特徴とするエンジンの排気マニホール
ド。 The exhaust manifold is connected to an exhaust port whose opening to the outside of the engine is formed into an elliptical cross section, and has a branch pipe made of a bent curved pipe, and the branch pipe is connected to the exhaust port of the branch pipe. The connecting end is formed to have an elliptical cross section corresponding to the opening shape of the exhaust port, and the connecting end of the branch pipe is such that the center of the elliptical opening corresponds to the bend of the branch pipe with respect to the center line of the branch pipe. An exhaust manifold for an engine, characterized in that it has a bulging portion that is offset inward in the bending direction of a branch pipe and bulges inward in the bending direction of a branch pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14175788U JPH0544507Y2 (en) | 1988-10-27 | 1988-10-27 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14175788U JPH0544507Y2 (en) | 1988-10-27 | 1988-10-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0261123U JPH0261123U (en) | 1990-05-07 |
| JPH0544507Y2 true JPH0544507Y2 (en) | 1993-11-11 |
Family
ID=31407107
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14175788U Expired - Lifetime JPH0544507Y2 (en) | 1988-10-27 | 1988-10-27 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0544507Y2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5727386A (en) * | 1995-04-03 | 1998-03-17 | Toyota Jidosha Kabushiki Kaisha | Structure of an exhaust manifold branch collecting portion |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2822170B2 (en) * | 1996-01-08 | 1998-11-11 | 川崎重工業株式会社 | Exhaust system for personal watercraft |
| JP5162419B2 (en) * | 2008-11-19 | 2013-03-13 | 株式会社ユタカ技研 | Manufacturing method of exhaust manifold |
-
1988
- 1988-10-27 JP JP14175788U patent/JPH0544507Y2/ja not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5727386A (en) * | 1995-04-03 | 1998-03-17 | Toyota Jidosha Kabushiki Kaisha | Structure of an exhaust manifold branch collecting portion |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0261123U (en) | 1990-05-07 |
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