JP4549033B2

JP4549033B2 - Heat transfer tube with fins

Info

Publication number: JP4549033B2
Application number: JP2003113328A
Authority: JP
Inventors: 正一郎臼井
Original assignee: Usui Co Ltd
Current assignee: Usui Co Ltd
Priority date: 2003-04-17
Filing date: 2003-04-17
Publication date: 2010-09-22
Anticipated expiration: 2023-04-17
Also published as: JP2004317060A

Description

【産業上の利用分野】
【０００１】
本発明は、ＥＧＲガス冷却装置等の多管式熱交換器、ラジエーター組込式オイルクーラーにて、冷却水、冷却風、カーエアコン用冷媒、その他の冷媒液等の冷却媒体と、ＥＧＲガス、煤を含有する燃焼排気ガス等の被冷却高温熱媒体流体との熱交換を行うために用いるもの等、種々の用途の伝熱管に係るものである。
【従来の技術】
【０００２】
【特許文献１】
特開平１１−１０８５７８号公報
【特許文献２】
特開２０００−１７９４１０号公報
【特許文献３】
特開２００１−２２７４１３号公報
【０００３】
従来、自動車のエンジン等では、排気ガスの一部を排気ガス系から取り出して、再びエンジンの吸気系に戻し、混合気や吸入空気に加えるＥＧＲシステムが、ガソリンエンジン、ディーゼルエンジンに用いられていた。ＥＧＲシステム、特にディーゼルエンジンの高ＥＧＲ率のクールドＥＧＲシステムでは、排気ガス中のNOxを低減し、燃費の悪化を防止するとともに、過剰な温度上昇によるＥＧＲバルブの機能低下や耐久性の低下を防止するため、高温化したＥＧＲガスを冷却水、冷却風、カーエアコン用冷媒、その他の冷媒液等の冷却媒体で冷却するＥＧＲガス冷却装置を設けている。
【０００４】
そして、このＥＧＲガス冷却装置として、上記特許文献１〜特許文献３の従来発明等に示す如く、内部をＥＧＲガスが流通可能な複数の細径の伝熱管を配置し、この伝熱管の外側に冷却水や冷却風、冷媒液等の冷却媒体を流通させる事により、伝熱管を介してＥＧＲガスと冷却媒体との熱交換を行うものが存在した。
【０００５】
上述の如きＥＧＲガス冷却装置で使用する伝熱管は、内周面が平滑な金属管が多く用いられているが、このような伝熱管ではＥＧＲガスの殆どが伝熱管の中心付近を高速に流動し、伝熱管の内表面側を通過するＥＧＲガスから熱が伝導されるのみで、冷却媒体との熱交換が良好に行われにくかった。この熱交換性能の向上のため、前記特許文献１、２の従来発明では、内周面に突起を突設した金属製の素管内に、平板を螺旋状に捻って形成したフィン部材を挿入配設して伝熱管を形成している。また、特許文献３では、素管内に平板状のフィン部材を一体に突出して伝熱管を形成している。
【０００６】
このように、素管内に螺旋状に捻ったフィン部材を配設したり平板状のフィン部材を一体に突設する事で、伝熱管の伝熱面積を増大させ、伝熱管の内表面を流動するＥＧＲガスだけでなく、中心付近を流動するＥＧＲガスの熱をフィン部材に伝達させ、ＥＧＲガスからの伝熱管への熱伝導効率を高めようとしていた。更に、フィン部材によって伝熱管内のＥＧＲガスの流れを乱流化して、ＥＧＲガスの伝熱管内の流動距離を長くし、伝熱管とＥＧＲガスとの接触時間を長くするとともに、境界層を剥離して、伝熱管を介したＥＧＲガスと冷却媒体との熱交換効率を高めようとするものであった。
【発明が解決しようとする課題】
【０００７】
しかしながら、上記特許文献１、２の従来技術では、フィン部材と素管との接触は、フィン部材の両側縁と素管の内周面の突起部分との断続した点接触である。そのため、フィン部材と素管との接触面積が少なく、フィン部材がＥＧＲガスの熱を受熱しても、このフィン部材から素管への熱伝達が十分に行われず、ＥＧＲガスと伝熱管の外周を流動する冷却媒体との熱交換効率を高めるには限界があった。
【０００８】
これに対して、特許文献３では、素管と板状フィンとを一体に設けているので、素管と板状フィンとは板状フィンの肉厚分の面接触となり、特許文献１、２の点接触に比べて素管と板状フィンとの熱伝導性は高まる。しかしながら、特許文献３では、フープ材を用いてロール成形によって円筒形に素管を形成する際に、フープ材の一端又は両端を、素管の内方に折り曲げて板状フィンを形成したり、予め所定の直径で形成した素管の外壁を、内方に押圧変形して板状フィンを形成しているので、製作に手数を要するものであった。
【０００９】
そのため、例えば使用目的に応じて熱交換性能の異なる複数種の伝熱管を形成する場合には、素管の成形時に、大小様々なフープ材を使用して形成したり、突設するフィン部材の枚数や大きさに応じて直径の異なる素管を複数形成する必要があり、製作工数が増えてコスト高となる可能性がある。また、特許文献１、２に於いても、上述の如き熱交換性能の異なる複数種の伝熱管を得るには、伝熱管の種類毎に螺旋のピッチ等を変えて、形状の異なる複数の螺旋状フィン部材を形成する必要があり、生産性に影響を及ぼす虞がある。
【００１０】
本発明は上述の如き課題を解決しようとするものであって、フィン部材を内装し熱交換効率に優れた伝熱管を、容易な製造方法で低コストに得る事を可能とするものである。また、使用目的に応じて熱交換性能の異なる複数種の伝熱管を、複数の形状の異なるフィン部材を個別に形成する等の煩雑な手数を必要とせずに、熱交換性能を調整する事を可能として、製品の汎用性や発展性を高めるものである。
【課題を解決するための手段】
【００１１】
本発明は上述の如き課題を解決するため、金属製の基板の一面に直交して、複数の板状フィンを互いに平行に突設し、この板状フィンを内側にして基板を円筒形に湾曲成形する事により形成した円筒形のフィン部材を、金属製の素管内に複数個直列に挿入配設し、フィン部材の円筒形とした基板の外周面を、素管の内周面に密着固定させるとともに板状フィンを素管の内方に、管軸方向放射状に突設し、この板状フィンの突出方向の先端を接触することなく流体の流通間隔を介して配置して成るものである。
【００１２】
また、フィン部材は、素管内に複数個を密着若しくは間隔を介して挿入配設しても良い。
【００１３】
また、板状フィンは、貫通孔又は長尺な凹凸条を設けても良い。
【作用】
【００１４】
本発明は上述の如く構成したものであり、伝熱管を得るには、金属材製の基板の一面に、この面と直交して複数の金属材製の板状フィンを、互いに平行に突設する。次に上記板状フィンを設けた一面を内側にして基板を円筒形に湾曲成形し、円筒形のフィン部材を形成する。この円筒形のフィン部材を、金属製の素管内に複数個、直列に挿入配設し、各フィン部材の基板の外周面を素管の内周面に密着固定させる事により本発明の伝熱管を形成する事ができる。
【００１５】
このように、熱伝導性に優れた金属材製の素管内に、金属材製であるとともに板状フィンを複数突設して伝熱面積を多くしたフィン部材を配設しているので、伝熱管全体の伝熱特性を高める事ができる。また、板状フィンと基板とは、板状フィンの肉厚幅での面接触となっており、この接触面を介して板状フィンと基板との熱伝導を良好に行う事ができる。
【００１６】
更に、フィン部材の基板は、外周面全体を素管の内周面と面接触させているので、素管と基板との熱伝導性も良好であり、基板を介して板状フィンと素管との熱伝導性を高める事ができる。また、板状フィンの存在により、伝熱管の内部を流動する流体に乱流を発生させるものとなり、伝熱管と流体との接触頻度を高めるとともに、素管の内表面付近に発生し易い境界層を剥離して、伝熱管を介した内外流体の熱交換を促進させる事ができ、熱交換性能の高い伝熱管を得る事ができる。
【００１７】
また、この熱交換性能の高い伝熱管を、前述の如く、基板に板状フィンを設けて円筒形に成形したフィン部材を、素管内に複数個を挿入配設するだけで形成する事ができるので、高度な製作技術を用いる事なく容易に形成する事ができ、廉価な製品を得る事ができる。また、伝熱管は、素管内に挿入するフィン部材の挿入個数を調整する事により、熱交換性能を変化させる事ができる。
【００１８】
また、前記フィン部材は、基板と板状フィンとを溶接やろう付け等により互いに接続固定する事で、流体の流動や伝熱管の振動等による板状フィンのブレや変形を防ぐ事ができる。更に、板状フィンや基板、及び基板が接触している素管の壁面のフレッティング等を抑制して、伝熱管の使用性や耐久性を向上させる事が可能となる。また、板状フィンと基板との熱伝導が、板状フィンの肉厚分での接触面だけでなく、ろう材や溶けた金属材のフィレットをも介しても行われ、双方の熱伝導性を高める事ができる。更に、フィン部材の基板の外周面と素管の内周面との間に多少の隙間を生じていても、ろう材や溶けた金属材が入り込んで隙間を閉塞するので、フィン部材と素管との熱伝導をより確実なものとする事ができる。
【００１９】
また、複数のフィン部材を素管に挿入配設する際は、隣接するフィン部材を互いに密着させて配設しても良いし、隣接するフィン部材との間に間隔を設けて配設しても良い。また、間隔を介して又は密着して隣接するフィン部材同士の板状フィンが、軸方向に同一平面上に配置されるように配設すれば、伝熱管の製作が容易となる。また、隣接するフィン部材同士の板状フィンが、同一平面上に配置されないよう、互いの板状フィンの位置を円周方向に適宜ずらしながら各フィン部材を配設しても良く、この場合は流体の流れが蛇行化して、流体から伝熱管への熱伝導性が高まるとともに、煤の付着・堆積を抑えて熱交換性能の低下を抑える事が可能となる。
【００２０】
また、フィン部材は、素管内に複数個を間隔を介して挿入配設した場合は、軽量な製品を得る事ができるし、フィン部材の配設位置では基板の肉厚分、流体の流通経路の断面積が狭くなり、フィン部材の非配設位置では、流通経路の断面積が大面積に復元する。このように、伝熱管内部を流動する流体が狭い流通経路から広い流通経路に流出する事により、流体の流れが乱流化し、流れの渦が多数発生する。そして、この流れの渦が伝熱管の内表面側を流動するので、フィン部材の非配設部に於いても流体の境界層が薄くなり、流体と伝熱管との熱伝達性が向上する。また、流体の乱流化により、伝熱管の内表面に付着した煤の剥離も促進され、熱伝導性の低下を抑える事ができる。
【００２１】
そして、フィン部材を間隔を介して複数個配設しているので、上記流れの絞り作用と流通経路の復元による乱流化を繰り返すものとなり、伝熱管の全長に渡って熱伝達性が向上する。そして、伝熱管の内部を流動する流体と伝熱管外部の流体との熱交換が促進され、温度効率が向上するとともに、伝熱管内表面及び中央を流通する流体の全体がムラ無く均一に冷却又は加熱されるものとなる。また、温度効率が向上するだけでなく、伝熱管内を流動する流体の流動速度が衰えず、伝熱管内を流動する事による流体の圧力損失を良好に防止する事ができる。
【００２２】
また、フィン部材を密着させて複数個配設した場合は、伝熱管の伝熱面積をより多くする事ができる。また、伝熱管内を流動する流体への流動抵抗が大きくなり、伝熱管内を高速で通過しようとする流体の伝熱管内での滞留時間を長くし、流体とフィン部材との接触頻度を高める事ができるので、伝熱管を介した内外流体の熱交換を効率的に行う事ができる。
【００２３】
また、特許文献１〜３等の従来発明の伝熱管では、使用目的や予算に応じた様々な熱交換性能を有する伝熱管を得るのは、伝熱管毎にフィン部材を複数形成したり、複雑な製作技術を必要とする等により、コスト高となっていた。しかし本発明の伝熱管は、前述の如く、素管内に配設するフィン部材の挿入個数を変えるだけで、熱交換性能の異なる複数種の伝熱管を容易に得る事ができる。即ち、素管とフィン部材とは同一のものを使用した場合でも、素管内に密接又は間隔を狭くして多くのフィン部材を挿入配設すれば、伝熱面積を大きく増大させる事ができるとともに、流体の乱流化による境界層の剥離や板状フィンと流体の接触頻度が高まり、熱交換性のより高い伝熱管を得る事ができる。そのため、高温のＥＧＲガスの冷却を行ったり、流動速度の高速な流体の熱交換を行う場合等に好適である。
【００２４】
逆に、素管内に配設するフィン部材の数を少なくすれば、上記に示すフィン部材の密な伝熱管に比べて伝熱面積は少なくなるが、従来の伝熱管に比べた場合では伝熱面積を多くする事ができる。更に、流体の乱流化による境界層の剥離等によって、良好な熱交換性能がえられ、且つ流体の圧力損失をより少なくする事ができるとともに、より軽量で廉価な伝熱管を得る事ができる。そのため、流体の流動圧が低く流動速度が遅い場合や、熱交換量の少ない流体に用いる等に好適なものとなる。
【００２５】
また、フィン部材の複数の板状フィンは、貫通孔又は長尺な凹凸条を設ければ、フィン部材の表面積がより広くなり、伝熱管の伝熱面積を更に増大させる事ができるとともに、伝熱管の内部を流動する流体の乱流化が更に促進されたり、流体の撹拌作用が生じるものとなり、境界層の剥離が促進され、伝熱管を介した内外流体の熱交換効率を高める事ができる。また、金属材に凹凸条や貫通孔を設けるのは、プレス加工等により容易に行う事ができ、伝熱管の生産性に影響を及ぼす事はないものである。
【００２６】
また、上記伝熱管は、自動車のエンジン、その他内燃機関、冷暖房等、熱交換を行う何れの装置にも用いる事ができる。そして、本発明の伝熱管を、エンジンのＥＧＲガス冷却装置、その他の多管式熱交換器に組付ければ、ＥＧＲガスの冷却を効率的に行う事ができる。従って、ＥＧＲシステム、特にディーゼルエンジンの高ＥＧＲ率のクールドＥＧＲシステムに於いて、排気ガス中のNOxを低減できるとともに、燃費の悪化も防止する事ができる。また、過剰な温度上昇を防止して、ＥＧＲバルブの劣化や機能低下も確実に防止する事ができる。
【００２７】
また、高温オイルを内部に流通させて、エンジン冷却水で冷却するラジエーターへの組込式オイルクーラー等に本発明の伝熱管を組付けても良く、優れた熱交換を行って、伝熱特性の高いオイルクーラーを得る事ができる。
【実施例】
【００２８】
以下、本発明の伝熱管を、自動車のクールドＥＧＲシステムに於けるＥＧＲガス冷却装置に使用した実施例を図面に於て詳細に説明する。図１は第１実施例の伝熱管の斜視図で、４枚の板状フィンを内方に突設したフィン部材を、間隔を設けて複数個金属製の素管内に挿入配設したものである。図２は、第１実施例のフィン部材を円筒形とする前の斜視図で、同一形状の４枚の板状フィンを基板に突設している。図３は、第２実施例の伝熱管の斜視図で、形成高さの異なる２種類の板状フィンを交互に突設し、合計８枚の板状フィンを内方に設設したフィン部材を、間隔を設けて複数個、金属製の素管内に配設したものである。図４は第２実施例のフィン部材を円筒形とする前の斜視図で、基板に形成高さの異なる８枚の板状フィンを交互に突設している。
【００２９】
また、図５は第３実施例の円筒形とする前のフィン部材の斜視図で、両表面に波状の凹凸条を設けた４枚の板状フィンを基板に突設している。図６は、第４実施例の円筒とする前のフィン部材の斜視図で、複数の貫通孔を設けた４枚の板状フィンを基板に突設している。また、図７は本発明の伝熱管を用いたＥＧＲガス冷却装置の概略図である。
【００３０】
そして、本発明の第１実施例を図１、図２、図７を用いて詳細に説明すれば、（１）は伝熱管で、内部をＥＧＲガスが流通可能な細径の金属製の素管（２）内に、管軸方向と平行に４枚の板状フィン（３）を内方に突設した金属製のフィン部材（４）を、間隔を介して複数個、直列に挿入配設して形成している。
【００３１】
上記素管（２）及びフィン部材（４）は、銅、アルミニウム、黄銅、又はステンレス等で形成する事により、熱伝導性に優れるとともにＥＧＲガスや凝縮液等に対する耐食性にも優れた伝熱管（１）を得る事ができる。尚、素管（２）とフィン部材（４）とは、同一の金属材で形成しても良いし、後述のろう付けや溶接を行う事が可能であれば、使用目的やコスト等に応じて、双方を異なる金属材で形成しても良い。
【００３２】
また、伝熱管（１）の耐食性の信頼性を更に高めるため、前述の如き金属材に、亜鉛、銅、錫、錫−亜鉛合金、ニッケル、亜鉛−ニッケル合金等から成る１層の犠牲腐食性のメッキ処理を行い、必要に応じクロメート被膜等を施しても良いし、金属材の外表面にニッケルをメッキし、このニッケルの外周面に更に亜鉛−ニッケル合金をメッキする等、２層以上のメッキ処理を行っても良い。また、これらのメッキ処理等が予め施された量産品の素管（２）やフィン部材（４）用の金属板を使用する事もでき、メッキ処理等の製作の手間を省いて、伝熱管の生産性を向上させる事ができる。
【００３３】
上記伝熱管（１）の製造のため、まずフィン部材（４）として、前記金属材製の平板を用いて長方形の基板（５）を形成するが、この基板（５）は、長手方向の形成長さを、素管（２）の内周面の円周長よりもやや短尺に形成している。そして、基板（５）の一面に、図２に示す如く、基板（５）の幅方向の両側辺と平行で、且つ基板（５）の一面と直交する４枚の板状フィン（３）を互いに平行に突設する事により、フィン部材（４）を形成している。この４枚の板状フィン（３）は、後述の如く基板（５）を円筒形とした際に、基板（５）の内周面から内方に略一定間隔で放射状に各板状フィン（３）が突出されるような間隔を設けて基板（５）に設けるとともに、各板状フィン（３）の一側端面全体が基板（５）の表面に面接触させて配設する。
【００３４】
また、板状フィン（３）と基板（５）とをろう付けして、板状フィン（３）の固定性を高めるとともに、前記板状フィン（３）と基板（５）との面接触を確実として、双方の熱伝導性を高めている。更に、このろう付けにより、板状フィン（３）と基板（５）との熱伝導面積が、板状フィン（３）の肉厚分の接触面積に加えて、ろう材のフィレットの肉厚の面積分、増大させる事ができ、板状フィン（３）と基板（５）との熱伝導性をより高める事ができる。また、ろう付けの際は、板状フィン（３）と基板（５）との接触面の一方又は双方にろう材をメッキしても良いし、板状フィン（３）と基板（５）の全体にろう材をメッキして行っても良いし、他の方法で行っても良い。また、ろう付けではなく、溶接により板状フィン（３）と基板（５）とを接続固定するものであっても良く、フィン部材（４）の構造が簡易であるから、ろう付け及び溶接の何れの場合も作業を容易に行う事ができる。
【００３５】
次に、図２に示す如きフィン部材（４）の基板（５）を、板状フィン（３）を突設した一面を内側にして、素管（２）の内径と略同一な外径とする円筒形に成形する。そして、この円筒形としたフィン部材（４）を複数個、素管（２）内に間隔を設けて直列に挿入配設する。ところで、フィン部材（４）は、基板（５）の長手方向の形成長さを素管（２）の内周面の円周長よりもやや短尺としているので、基板（５）の幅方向の一対の両端縁を付合わせて円筒形としたフィン部材（４）の外径は、素管（２）の内径よりもやや小径となる。そのため、この素管（２）よりも小径とした状態でフィン部材（４）を素管（２）内に挿入する事により、前記挿入配設作業を円滑且つ容易に行う事ができる。また、挿入配設後は、基板（５）の復元力が作用し、フィン部材（４）の外径が拡開する事で、フィン部材（４）の外周面を素管（２）の内周面に密着固定させる事ができ、フィン部材（４）の素管（２）内での固定性が得られるものとなる。
【００３６】
そして、この固定性を更に高めるため、素管（２）の内周面とこれに密着するフィン部材（４）の外周面とを溶接又はろう付けにより接続固定する。このフィン部材（４）の素管（２）への固定性の向上により、ＥＧＲガスの流動や伝熱管（１）の振動等による板状フィン（３）のブレや変形、この板状フィン（３）が接触している基板（５）、及び基板（５）が接触している素管（２）の壁面のフレッティング等を抑制して、伝熱管（１）の使用性や耐久性を向上させる事が可能となる。また、フィン部材（４）の基板（５）の外周面と素管（２）の内周面との間に、多少の隙間を生じていた場合でも、ろう材や溶けた金属材が隙間に入り込んで隙間を閉塞するので、板状フィン（３）と素管（２）との熱伝導性及び固定性を高める事ができる。
【００３７】
また、ろう付けによりフィン部材（４）と素管（２）とを接続固定する場合は、素管（２）へのフィン部材（４）の挿入前に、予めフィン部材（４）の基板（５）の少なくとも長尺側の両側縁、或いは基板（５）の外表面全体にろう材をメッキしておく。また、このろう材のメッキは、好ましくは作業が容易な事から、フィン部材（４）の全体、即ち基板（５）及び板状フィン（３）の全表面に施しても良いし、素管（２）の内周面にろう材をメッキしても良い。また、フィン部材（４）の形成素材である金属板にろう材をクラッドし、このクラッド材を加工してフィン部材（４）を形成しても良い。
【００３８】
また、基板（５）の両側縁にろう材付着用のバインダーを塗布したフィン部材（４）を素管（２）に挿入後、該素管（２）内にパウダー状のろう材を供給しても良い。他のろう付け手段として、基板（５）の長手方向の両側縁にろう材ペーストを供給したフィン部材（４）を素管（２）へ挿入しても良いし、素管（２）内にフィン部材（４）を挿入後、該素管（２）内にろう材ペーストを供給しても良い。そして、伝熱管（１）の製作時にろう付けを行っても良いし、或いは伝熱管（１）を後述のＥＧＲガス冷却装置（１０）に組付け後に、ろう付けを行っても良い。
【００３９】
上述の如く形成した伝熱管（１）では、４枚の板状フィン（３）を内方に突設したフィン部材（４）を複数内装する事により伝熱面積が増大し、伝熱管（１）の内部空間（６）を流動するＥＧＲガスの熱を、素管（２）の内表面だけでなく板状フィン（３）に効率的に伝熱する事ができる。また、この板状フィン（３）に伝達された熱は、板状フィン（３）が面接触する基板（５）に伝達された後、この基板（５）と素管（２）との接触面を介して素管（２）の内表面に伝達される。そして、これらのＥＧＲガスからの熱が素管（２）の外表面を介して外部を流動する冷媒液に効率的に放熱されるものとなる。
【００４０】
また、ＥＧＲガスの流通経路である内部空間（６）内に、複数の板状フィン（３）が突出する事により、ＥＧＲガスに乱流を発生させるものとなり、フィン部材（４）の配設位置での境界層を剥離して、伝熱管（１）を介したＥＧＲガスと冷媒液との熱交換を促進させる事ができる。更に、本実施例では、素管（２）内に複数のフィン部材（４）を間隔を設けて配設している。そのため、フィン部材（４）の配設位置では基板（５）の肉厚分、内部空間（６）の断面積が狭くなり、フィン部材（４）の非配設位置では、内部空間（６）の断面積が大面積に復元する。
【００４１】
このように、伝熱管（１）内部を流動するＥＧＲガスが狭い空間から広い空間に流出する事により、ＥＧＲガスの流れの乱流化が促進され、流れの渦が多数発生する。そして、この流れの渦が素管（２）の内表面側を流動するので、フィン部材（４）の非配設部に於いてもＥＧＲガスの境界層が薄くなり、ＥＧＲガスと素管（２）との熱伝導性が向上する。そして、素管（２）内にフィン部材（４）を間隔を介して複数個配設しているので、上記流れの絞り作用と内部空間（６）の大面積への復元による乱流化を繰り返すものとなり、伝熱管（１）の全長に渡って熱伝導性が向上する。
【００４２】
従って、伝熱管（１）の内部空間（６）を流動するＥＧＲガスと伝熱管（１）の外部を流動する冷媒液との熱交換が促進され、温度効率が向上するとともに、伝熱管（１）の内表面側及び中央側を流通するＥＧＲガスの全体がムラ無く均一に冷却又は加熱されるものとなる。また、温度効率が向上するだけでなく、伝熱管（１）内を流動するＥＧＲガスの流動速度が衰えず、伝熱管（１）内を流動する事による流体の圧力損失を良好に防止する事ができる。更に、ＥＧＲガスの乱流化により、素管（２）の内表面に付着した煤の剥離も促進され、熱伝導性の低下を良好に抑える事ができる。
【００４３】
そして、上述の如き伝熱管（１）を組付けたＥＧＲガス冷却装置（１０）は、図７に示す如く、円筒形の胴管（１１）の両端にチューブシート（１２）を一対接続し、内部を密閉可能としている。そして、一対のチューブシート（１２）間に、本実施例の伝熱管（１）を複数本、チューブシート（１２）を貫通して接続配置している。また、胴管（１１）の両端には、一対のボンネット（１６）を接続し、各ボンネット（１６）の中央にＥＧＲガスの流入口（１４）と流出口（１５）とを設けている。
【００４４】
更に、胴管（１１）の外周には、エンジン冷却水や冷却風等の冷却媒体の導入路（１７）と導出路（１８）を設ける事により、一対のチューブシート（１２）で仕切られた気密空間内を、冷却媒体が流通可能な熱交換部（１３）としている。また、この熱交換部（１３）内に、複数の支持板（２０）を接合配置し、この支持板（２０）に設けた挿通孔（２１）に、伝熱管（１）を挿通する事により、バッフルプレートとして伝熱管（１）を安定的に支持するとともに、熱交換部（１３）内を流動する冷却媒体の流れを蛇行化している。
【００４５】
上記ＥＧＲガス冷却装置（１０）に於いて、エギゾーストマニホールド側から流入口（１４）を介して高温化したＥＧＲガスが胴管（１１）内に導入されると、このＥＧＲガスは胴管（１１）内に複数配置した伝熱管（１）内に流入する。この伝熱管（１）を配置した熱交換部（１３）では、予め伝熱管（１）の外部にエンジン冷却水等の冷却媒体を流通しているので、伝熱管（１）の外表面を介してＥＧＲガスと冷却媒体とで熱交換が行われる。
【００４６】
この伝熱管（１）は、前述の如く、フィン部材（４）の配設により伝熱面積を増大させるとともに、ＥＧＲガスの流れの絞り作用と内部空間（６）の大面積への復元によるＥＧＲガスの乱流化を生じさせる事で、フィン部材（４）と素管（２）との熱伝導性を高めている。そのため、素管（２）の内表面側のＥＧＲガスの熱だけでなく、中央付近を流動するＥＧＲガスの熱も、フィン部材（４）を介して素管（２）の内表面に伝熱された後、素管（２）の外表面を介して冷却媒体に放熱され、従来に比べてＥＧＲガスへの優れた冷却効果が得られる。
【００４７】
このように良好に冷却されたＥＧＲガスは、流出口（１５）を介してＥＧＲガス冷却装置（１０）から流出し、インテークマニホールド側に戻される。従って、ＥＧＲバルブの高温化を防止して、ＥＧＲバルブの優れた機能性と耐久性を得る事ができるとともに、吸入空気の温度を低下するのでNOxの低減と良好な燃費が可能となる。また、伝熱管（１）内でのＥＧＲガスの乱流化により、ＥＧＲガスに混入する煤の剥離が促進されて、大きな塊となるのを防ぐ事ができ、目詰まり等に起因する冷却性能の劣化やエンジントラブルを防ぐ事も可能となる。
【００４８】
上述の如く、本発明の同一形状の伝熱管（１）を複数配設したＥＧＲガス冷却装置（１０）では、ＥＧＲガスへの優れた冷却効果が得られる。しかしながら、ＥＧＲガス冷却装置（１０）では、装置内に流入するＥＧＲガスは、流入口（１４）から断面積の大きな胴管（１１）内に導入され、外方向に拡散しながら伝熱管（１）方向に流動する。そのため、胴管（１１）の中央付近ではＥＧＲガスは高圧状態であり、この中央付近の伝熱管（１）内に高速に流入し易いが、流入口（１４）からの距離が大きくなる程、中央付近に比べＥＧＲガスの圧力が低く流動速度も遅くなっていくため、外方に配置した伝熱管（１）ではＥＧＲガスが流入しにくいものとなる。その結果、胴管（１１）内の中央付近の伝熱管（１）では交換熱量が多く効率的な熱交換が行われるが、中央から離れるに従って伝熱管（１）での交換熱量が少なくなり、ＥＧＲガス冷却装置（１０）の優れた熱交換機能を十分に発揮できなくなる場合がある。
【００４９】
この不具合を解消するため、ＥＧＲガスに対する流動抵抗の異なる複数の伝熱管（１）を形成し、図７の如きＥＧＲガス冷却装置（１０）の胴管（１１）内に於いて、ＥＧＲガスの流入の難易に対応して、流動抵抗の異なる伝熱管（１）を配設している。このような伝熱管（１）の配設とする事により、胴管（１１）内の全ての伝熱管（１）に均一にＥＧＲガスを通過させて、ＥＧＲガスの効率的な冷却を可能とするものである。
【００５０】
この、流動抵抗の調整は、フィン部材（４）の板状フィン（３）の枚数を増減しても良いが、本実施例では素管（２）内に挿入配設するフィン部材（４）の個数を増減する事によって伝熱管（１）のＥＧＲガスに対する流動抵抗を調整している。そして、流入口（１４）に近い胴管（１１）の中央付近では、ＥＧＲガスの圧力が高く伝熱管（１）内に流入し易いので、フィン部材（４）の挿入個数を多くして、流体への流動抵抗を大きくした伝熱管（１）を配設している。また、ＥＧＲガスの流入口（１４）から離れる程、ＥＧＲガスの圧力が小さくなって伝熱管（１）内に流入しにくくなるので、流入口（１４）からの距離に応じてフィン部材（４）の挿入個数を少なくして、流動抵抗を小さくした伝熱管（１）を各々配設する。
【００５１】
上述の如く伝熱管（１）を配設したＥＧＲガス冷却装置（１０）では、まず流入口（１４）から、断面積の大きなボンネット（１６）内にＥＧＲガスが導入されると、ＥＧＲガスの殆どは胴管（１１）の中央付近に配設した伝熱管（１）内に流入して高速に通過しようとする。しかし、この中央付近の伝熱管（１）は、多数のフィン部材（４）を内装しているので、ＥＧＲガスへの流動抵抗が大きく、伝熱管（１）へのＥＧＲガスの流入量が制限される。この、中央付近の伝熱管（１）へのＥＧＲガスの流入が制限された分、ＥＧＲガスがボンネット（１６）内を径方向に流動するものとなり、流入口（１４）から離れた外方の伝熱管（１）にもＥＧＲガスが流入し易いものとなる。従って、胴管（１１）内の全ての伝熱管（１）に、より均一にＥＧＲガスを流入させる事ができる。
【００５２】
そして、胴管（１１）の中央付近に配設した伝熱管（１）では、多くのフィン部材（４）を内装しているので伝熱面積を大きく増大させる事ができ、板状フィン（３）によるＥＧＲガスの乱流化によって、ＥＧＲガスと板状フィン（３）との接触頻度を高める事ができる。また、ＥＧＲガスの乱流化による境界層の剥離等により、伝熱管（１）の熱伝導性が向上して、伝熱管（１）を介したＥＧＲガスと冷却媒体との熱交換を効率的に行う事ができる。
【００５３】
一方、胴管（１１）の外方に配設した伝熱管（１）では、フィン部材（４）の挿入個数を少なくして、ＥＧＲガスの流動抵抗を小さくしているから、伝熱管（１）内を流動するＥＧＲガスの圧力損失の少ない流動が可能となる。また、フィン部材（４）の挿入個数が少なくても、フィン部材（４）の存在により従来に比べて伝熱面積を多くする事ができ、フィン部材（４）と素管（２）との熱伝導性にも優れている。更に、フィン部材（４）の配設位置での流れの絞り作用とフィン部材（４）の非配設位置での内部空間（６）の大面積への復元の繰り返しにより、ＥＧＲガスの乱流化も促進され、伝熱管（１）の全長に渡って熱伝達性が向上する。従って、外方に配設した伝熱管（１）に於いても、ＥＧＲガスと冷媒液との交換熱量が多く、伝熱管（１）としての熱交換機能を十分に発揮する事ができる。
【００５４】
このように、胴管（１１）内に配設した何れの伝熱管（１）に於いても、ＥＧＲガスと冷媒液との熱交換が効率的に行われるので、ＥＧＲガス冷却装置（１０）に導入されたＥＧＲガス全体が、ムラ無く均一に冷却されるものとなり、熱交換性能を十分発揮する事が可能な高性能のＥＧＲガス冷却装置（１０）を得る事ができる。
【００５５】
そして、従来技術の伝熱管では、素管の一端から他端までの長尺な螺旋状のフィン部材を配設したり、素管の壁面を折り畳んで平板状のフィン部材を内方に突設している。そのため、上述の如き流体の流動抵抗の異なる複数種の伝熱管を形成する際には、フィン部材の螺旋のピッチを変えて形成したり、素管の折り畳み回数を増やしてフィン部材の数を多くする等の必要があり、製作に手間やコストがかかって実施が困難である。しかし、本発明では前述の如く、素管（２）内に挿入配設するフィン部材（４）の個数を変えるだけで、流動抵抗の異なる伝熱管（１）を容易に形成する事ができ、フィン部材（４）を同一形状で大量生産する事が可能である。しかも素管（２）へのフィン部材（４）の配設作業も、高度な製作技術を必要とする事なく、容易に行う事が可能であるので、本発明の伝熱管（１）は、廉価な実施が可能となる。
【００５６】
また、上記第１実施例の伝熱管（１）では、素管（２）内に配設するフィン部材（４）は、基板（５）の内周面から軸中心方向に同一形状の４枚の板状フィン（３）を突設しているが、他の異なる第２実施例の伝熱管（１）では、図３に示す如く、フィン部材（４）に形成高さの異なる８枚の板状フィン（３）を突設している。このようなフィン部材（４）を形成するには、図４に示す如く、素管（２）の内周面の円周長よりも、長手方向の長さをやや短尺とした基板（５）の一面に、第１実施例と同形の板状フィン（３）を４枚と、これらと形成幅と形成長さは同一であるが形成高さが低い板状フィン（３）を４枚とを、間隔を介して交互に接続固定している。この高低差のある板状フィン（３）を設けた基板（５）を、円筒形に成形して得たフィン部材（４）を、素管（２）内に複数個、間隔を介して挿入配設している。
【００５７】
また、この場合も、フィン部材（４）の外径を縮径して素管（２）の内径よりも小径としながら挿入する事により、作業が容易となる。そして、配設完了後は、基板（５）の復元力によりフィン部材（４）の外周面が素管（２）の内周面に弾性的に密着固定されるので、フィン部材（４）の固定性が得られる。また、各フィン部材（４）の板状フィン（３）と基板（５）、及び基板（５）の外周面と素管（２）の内周面とを、溶接やろう付け等により接続する事により、フィン部材（４）と素管（２）との固定性及び熱伝導性を高める事が可能となる。
【００５８】
上述の如く形成した第２実施例の伝熱管（１）では、高低差のある８枚の板状フィン（３）を突設したフィン部材（４）を内装する事により、伝熱管（１）の伝熱面積を更に増大させる事ができるとともに、ＥＧＲガスの乱流化も更に促進される。そして、フィン部材（４）を介して、素管（２）に効率的にＥＧＲガスの熱を伝達する事ができる。更に、フィン部材（４）の配設位置での流れの絞り作用とフィン部材（４）の非配設位置での内部空間（６）の大面積への復元の繰り返しにより、ＥＧＲガスの乱流化を繰り返すものとなり、伝熱管（１）の全長に渡って熱伝達性が向上する。従って、伝熱管（１）を介してＥＧＲガスと冷却媒体との熱交換を効率的に行う事が可能となる。
【００５９】
また、上記第１、第２実施例では、フィン部材（４）の基板（５）の長手方向の形成長さを、素管（２）の内周面の円周長よりもやや短尺としているので、フィン部材（４）の外周面を弾性復元力により素管（２）の内周面に密着固定させた際に、図１、図３に示す如く、フィン部材（４）の幅方向の互いの両端縁との間に隙間を生じる。このような隙間を生じていても、フィン部材（４）の外周面と素管（２）の内周面とをろう付けや溶接により接続固定しているので、固定性に何等支障はないし、ろう材や金属材の充填により、この隙間を閉塞する事も可能である。
【００６０】
ここで、他の異なる実施例としてフィン部材（４）の基板（５）の長手方向の形成長さを、素管（２）の内周面の円周長と略同一に形成しても良い。このようなフィン部材（４）であっても、基板（５）を円筒形に湾曲成形しただけであるから、基板（５）の幅方向の両側を積層する事でフィン部材（４）の外径を縮径して、素管（２）の内径よりも小径とする事ができ、素管（２）への挿入作業を容易に行う事ができる。この挿入配設完了後は、基板（５）の復元力によりフィン部材（４）の外周面が素管（２）の内周面に密着固定するとともに、フィン部材（４）の幅方向の互いの両端縁が隙間を生じる事なく当接するものとなり、フィン部材（４）の安定した固定性が得られるだけでなく、外観も良好なものとなる。
【００６１】
また、上記第１、第２実施例の伝熱管（１）では、板状フィン（３）の表面に波状等の凹凸や貫通孔等を何等設けていない平滑なものとしているが、他の異なる第３実施例では、図５に示す如く、板状フィン（３）の両表面に、管軸方向に平行な複数の波状の凹凸条（７）を設けている。この凹凸条（７）の形成により、フィン部材（４）の伝熱面積を更に増大させる事ができ、伝熱管（１）の熱伝導性を向上させて、優れた熱交換性能を得る事ができる。また、このような凹凸条（７）は、プレス加工等により金属材でも簡単に設ける事ができ、伝熱管（１）の容易な製作が可能となる。
【００６２】
また、図６に示す他の異なる第４実施例では、板状フィン（３）に複数の円形の貫通孔（８）を開口している。このような貫通孔（８）の開口によっても、フィン部材（４）の伝熱面積をより増大させる事ができるとともに、ＥＧＲガス等の流体が貫通孔（８）を通過する事により、乱流化が生じる。更に、フィン部材（４）にエッヂ部が多くなり、流体の乱流化を更に促進して、境界層の剥離により熱伝導効率を向上させる事ができ、熱交換性能に優れた伝熱管（１）を得る事ができる。また、この貫通孔（８）の開口作業も、プレス加工等により容易に行う事ができる。また、貫通孔（８）は、円形ではなく、楕円形、長円形、三角形、四角形、その他の多角形等の形状で開口するものであっても良い。
【００６３】
また、上記第１〜第４実施例では、基板（５）に突設する複数の板状フィン（３）を、基板（５）の幅方向の両側辺と平行に配設して、板状フィン（３）を流体の流動方向と平行に配置している。しかし、他の異なる実施例として、板状フィン（３）を、基板（５）の幅方向の両側辺に対して斜めに配設する事により、流体の流動方向に対して板状フィン（３）をテーパー状に配設しても良い。また、幅方向に弧状に湾曲形成した板状フィン（３）を基板（５）に設ける事により、流体の流動方向に対して板状フィン（３）を弧状に配設するものであっても良い。また、板状フィン（３）の先端側を基板（５）方向に弧状に湾曲形成したり、斜め方向に捻り形成しても良い。また、第３実施例では、板状フィン（３）の波状の凹凸条（７）は、管軸方向即ち幅方向に平行なものとしているが、板状フィン（３）の高さ方向に平行な波状の凹凸条（７）を設けたものであっても良い。また、矩形、Ｖ字形、その他の凹凸条（７）等を板状フィン（３）に設けるものであっても良い。
【００６４】
また、上記各実施例では、ＥＧＲガス冷却装置（１０）に本発明の伝熱管（１）を組付けたものとして説明しているが、他の異なる多管式熱交換器に本発明の伝熱管（１）を用いても良く、優れた熱交換性能を得る事ができる。また、エンジンオイル、ミッションオイル、ＡＴＦ、パワステオイル等の高温オイルを内部に流通させて、この高温オイルをエンジン冷却水で冷却するラジエーターへの組込式オイルクーラーに、本発明の伝熱管（１）を組付ける事もできる。そして、本発明の伝熱面積が広く且つ熱伝導性の高い伝熱管（１）を介して、伝熱管（１）内を流通するエンジン冷却水と伝熱管（１）外部を流通する被冷却オイルとの熱交換が促進され、被冷却オイルの冷却を均一且つ効率的に行えるものである。
【発明の効果】
【００６５】
本発明は上述の如く構成したもので、熱伝導性に優れる金属製の素管内に、複数の板状フィンを内方に突設した金属製のフィン部材を複数個配設しているので、伝熱管の伝熱面積を増大させる事ができる。また、この板状フィンの突設により、伝熱管内を流動する流体の乱流化を促進して、素管の内表面付近に発生し易い境界層を剥離して、伝熱管を介した内外流体の熱交換を促進させる事ができ、熱交換性能の高い伝熱管を得る事ができる。
【００６６】
また、板状フィンを突設した基板を円筒形に成形して形成したフィン部材を、素管内に複数配設するだけで簡易に製作可能で、熱交換性能に優れる製品を廉価に提供する事が可能となる。更に、素管内へのフィン部材の挿入個数を調整する事により、伝熱管の熱交換性能を調整する事が可能となる。そして、この熱交換性能に優れる伝熱管を、多管式熱交換器や、ラジエーター組込式オイルクーラー等に使用する事により、伝熱特性の高い製品を得る事ができる。
【図面の簡単な説明】
【図１】本発明の第１実施例の伝熱管を示す斜視図。
【図２】第１実施例のフィン部材の斜視図で、４枚の板状フィンを基板に突設した状態を示す。
【図３】本発明の第２実施例の伝熱管を示す斜視図。
【図４】第２実施例のフィン部材の斜視図で、形成高さの異なる８枚の板状フィンを基板に突設した状態を示す。
【図５】第３実施例のフィン部材の斜視図で、両表面に凹凸条を設けた４枚の板状フィンを基板に突設した状態を示す。
【図６】第４実施例のフィン部材の斜視図で、複数の貫通孔を設けた４枚の板状フィンを基板に突設した状態を示す。
【図７】本発明の伝熱管を組付けたＥＧＲガス冷却装置の一部切り欠き平面図。
【符号の説明】
２素管
３板状フィン
４フィン部材
５基板
７凹凸条
８貫通孔[Industrial application fields]
[0001]
The present invention provides a multi-tube heat exchanger such as an EGR gas cooling device, a radiator built-in oil cooler, a cooling medium such as cooling water, cooling air, a refrigerant for a car air conditioner, other refrigerant liquid, EGR gas, The present invention relates to heat transfer tubes for various uses such as those used for heat exchange with a cooled high-temperature heat medium fluid such as combustion exhaust gas containing soot.
[Prior art]
[0002]
[Patent Document 1]
JP-A-11-108578
[Patent Document 2]
JP 2000-179410 A
[Patent Document 3]
JP 2001-227413 A
[0003]
Conventionally, in an automobile engine or the like, an EGR system in which a part of exhaust gas is extracted from the exhaust gas system, returned to the engine intake system, and added to the mixture or intake air has been used for gasoline engines and diesel engines. . EGR systems, especially cooled EGR systems with a high EGR rate for diesel engines, reduce NOx in exhaust gas, prevent fuel consumption deterioration and prevent deterioration of EGR valve function and durability due to excessive temperature rise. Therefore, an EGR gas cooling device that cools the heated EGR gas with a cooling medium such as cooling water, cooling air, a car air conditioner refrigerant, or other refrigerant liquid is provided.
[0004]
And as this EGR gas cooling device, as shown in the conventional invention of the said patent document 1-patent document 3, etc., the several small diameter heat exchanger tube which can distribute | circulate an EGR gas is arrange | positioned inside this heat exchanger tube. There exist some which perform heat exchange with EGR gas and a cooling medium via a heat exchanger tube by circulating cooling media, such as cooling water, cooling air, and a refrigerant liquid.
[0005]
The heat transfer tube used in the EGR gas cooling apparatus as described above is often a metal tube with a smooth inner peripheral surface, but in such a heat transfer tube, most of the EGR gas flows in the vicinity of the center of the heat transfer tube at high speed. However, heat is only conducted from the EGR gas passing through the inner surface side of the heat transfer tube, and heat exchange with the cooling medium is difficult to be performed. In order to improve this heat exchange performance, in the conventional inventions of Patent Documents 1 and 2, a fin member formed by spirally twisting a flat plate is inserted and arranged in a metal element tube having a protrusion protruding on the inner peripheral surface. To form a heat transfer tube. Moreover, in patent document 3, the flat fin member is integrally protruded in the raw tube, and the heat exchanger tube is formed.
[0006]
In this way, by arranging a helically twisted fin member in the element tube or by projecting a flat fin member integrally, the heat transfer area of the heat transfer tube is increased and the inner surface of the heat transfer tube flows. In addition to the EGR gas, the heat of the EGR gas flowing in the vicinity of the center is transmitted to the fin member to increase the efficiency of heat conduction from the EGR gas to the heat transfer tube. Furthermore, the flow of the EGR gas in the heat transfer tube is turbulent by the fin member, the flow distance of the EGR gas in the heat transfer tube is lengthened, the contact time between the heat transfer tube and the EGR gas is lengthened, and the boundary layer is peeled off Thus, the heat exchange efficiency between the EGR gas and the cooling medium via the heat transfer tube is to be increased.
[Problems to be solved by the invention]
[0007]
However, in the prior arts of Patent Documents 1 and 2, the contact between the fin member and the raw pipe is an intermittent point contact between both side edges of the fin member and the protruding portion of the inner peripheral surface of the raw pipe. Therefore, the contact area between the fin member and the raw tube is small, and even if the fin member receives the heat of the EGR gas, the heat transfer from the fin member to the raw tube is not sufficiently performed, and the outer periphery of the EGR gas and the heat transfer tube There was a limit to increasing the efficiency of heat exchange with the flowing cooling medium.
[0008]
On the other hand, in Patent Document 3, since the raw pipe and the plate-like fin are provided integrally, the raw pipe and the plate-like fin are in surface contact with the thickness of the plate-like fin, and Patent Documents 1 and 2 are provided. Compared with the point contact, the thermal conductivity between the raw tube and the plate fin is increased. However, in Patent Document 3, when forming an element pipe into a cylindrical shape by roll forming using a hoop material, one end or both ends of the hoop material are bent inward of the element pipe to form a plate-like fin, Since the plate-like fins are formed by pressing and deforming the outer wall of the raw tube formed in advance with a predetermined diameter inward, it takes time to manufacture.
[0009]
Therefore, for example, when forming a plurality of types of heat transfer tubes having different heat exchange performance depending on the purpose of use, when forming the raw tube, it is formed using a large or small hoop material, or a fin member to be projected. Depending on the number and size, it is necessary to form a plurality of element tubes with different diameters, which may increase the number of manufacturing steps and increase the cost. Also, in Patent Documents 1 and 2, in order to obtain a plurality of types of heat transfer tubes having different heat exchange performance as described above, a plurality of spirals having different shapes can be obtained by changing the spiral pitch or the like for each type of heat transfer tubes. It is necessary to form a fin-like member, which may affect productivity.
[0010]
The present invention is intended to solve the above-described problems, and makes it possible to obtain a heat transfer tube having a fin member therein and excellent in heat exchange efficiency at a low cost by an easy manufacturing method. In addition, it is possible to adjust the heat exchange performance without requiring complicated steps such as individually forming a plurality of types of heat transfer tubes having different heat exchange performance depending on the purpose of use. It is possible to improve the versatility and development of products.
[Means for Solving the Problems]
[0011]
In order to solve the above-described problems, the present invention has a plurality of plate-like fins protruding in parallel with each other perpendicular to one surface of a metal substrate, and the substrate is curved in a cylindrical shape with the plate-like fins inside. A plurality of cylindrical fin members formed by molding are inserted and arranged in series in a metal base tube, and the outer peripheral surface of the fin-shaped substrate is closely fixed to the inner peripheral surface of the base tube Let At the same time, plate fins project radially inward in the axial direction of the pipes, and the fins in the projecting direction of the plate fins are arranged through the fluid flow interval without contact. It is made up of.
[0012]
Further, a plurality of fin members may be inserted and disposed in the raw tube through close contact or intervals.
[0013]
Further, the plate-like fin may be provided with a through hole or a long uneven strip.
[Action]
[0014]
The present invention is configured as described above. In order to obtain a heat transfer tube, a plurality of plate fins made of a metal material are provided in parallel with each other on one surface of a metal substrate perpendicular to this surface. To do. Next, the substrate is curved and formed into a cylindrical shape with the one surface provided with the plate-like fins inside, thereby forming a cylindrical fin member. A plurality of the cylindrical fin members are inserted and arranged in series in a metal base tube, and the outer peripheral surface of the substrate of each fin member is closely fixed to the inner peripheral surface of the base tube, thereby the heat transfer tube of the present invention. Can be formed.
[0015]
As described above, since the fin member made of a metal material and having a plurality of plate-like fins protruding to increase the heat transfer area is disposed in the metal tube having excellent heat conductivity. The heat transfer characteristics of the entire heat pipe can be improved. Further, the plate-like fin and the substrate are in surface contact with the thickness of the plate-like fin, and heat conduction between the plate-like fin and the substrate can be satisfactorily performed via this contact surface.
[0016]
Furthermore, since the board | substrate of a fin member has made the whole outer peripheral surface surface-contact with the inner peripheral surface of a raw material pipe, the thermal conductivity of a raw material pipe and a board | substrate is also favorable, and a plate-like fin and a raw material pipe | tube via a board | substrate The thermal conductivity can be increased. In addition, the presence of plate-like fins generates turbulent flow in the fluid flowing inside the heat transfer tube, increasing the contact frequency between the heat transfer tube and the fluid, and a boundary layer that tends to occur near the inner surface of the elementary tube The heat exchange of the inner and outer fluids via the heat transfer tube can be promoted, and a heat transfer tube with high heat exchange performance can be obtained.
[0017]
Further, as described above, the heat transfer tube having high heat exchange performance can be formed by simply inserting a plurality of fin members formed in a cylindrical shape by providing plate-like fins on the substrate. Therefore, it can be formed easily without using advanced manufacturing techniques, and an inexpensive product can be obtained. Further, the heat transfer tube can change the heat exchange performance by adjusting the number of fin members inserted into the raw tube.
[0018]
Further, the fin member can prevent the plate-like fins from being shaken or deformed due to fluid flow or heat transfer tube vibration by connecting and fixing the substrate and the plate-like fins together by welding or brazing. Furthermore, it is possible to improve the usability and durability of the heat transfer tube by suppressing fretting of the plate-like fins, the substrate, and the wall surface of the raw tube in contact with the substrate. In addition, the heat conduction between the plate fin and the substrate is performed not only through the contact surface at the thickness of the plate fin, but also through a filler or a melted metal fillet. Can be increased. Furthermore, even if there is a slight gap between the outer peripheral surface of the fin member substrate and the inner peripheral surface of the blank tube, brazing material or melted metal material enters and closes the gap. It is possible to ensure more reliable heat conduction.
[0019]
In addition, when inserting and arranging a plurality of fin members in the raw tube, the adjacent fin members may be arranged in close contact with each other, or provided with a gap between the adjacent fin members. Also good. Moreover, if the plate-like fins of the fin members adjacent to each other with an interval or in close contact are arranged on the same plane in the axial direction, the heat transfer tube can be easily manufactured. Further, in order to prevent the plate fins of adjacent fin members from being arranged on the same plane, the fin members may be arranged while appropriately shifting the positions of the plate fins in the circumferential direction. The flow of the fluid meanders to increase the thermal conductivity from the fluid to the heat transfer tube, and it is possible to suppress the adhesion / deposition of soot and the deterioration of the heat exchange performance.
[0020]
In addition, when a plurality of fin members are inserted and arranged in the raw tube at intervals, a lightweight product can be obtained. And the cross-sectional area of the flow path is restored to a large area at the position where the fin member is not disposed. As described above, when the fluid flowing in the heat transfer tube flows out from the narrow flow path to the wide flow path, the flow of the fluid becomes turbulent and many flow vortices are generated. And since the vortex of this flow flows on the inner surface side of the heat transfer tube, the boundary layer of the fluid becomes thin even in the non-arranged portion of the fin member, and the heat transfer property between the fluid and the heat transfer tube is improved. Moreover, the turbulent flow of the fluid promotes the peeling of the soot adhering to the inner surface of the heat transfer tube, and can suppress a decrease in thermal conductivity.
[0021]
Since a plurality of fin members are arranged at intervals, the turbulent flow is repeated by the flow throttling action and the restoration of the flow path, and the heat transfer performance is improved over the entire length of the heat transfer tube. . Then, heat exchange between the fluid flowing inside the heat transfer tube and the fluid outside the heat transfer tube is promoted, temperature efficiency is improved, and the entire fluid flowing through the inner surface and the center of the heat transfer tube is uniformly cooled or uniformly distributed. It will be heated. Further, not only the temperature efficiency is improved, but also the flow rate of the fluid flowing in the heat transfer tube does not decline, and the pressure loss of the fluid due to the flow in the heat transfer tube can be well prevented.
[0022]
In addition, when a plurality of fin members are disposed in close contact, the heat transfer area of the heat transfer tube can be increased. In addition, the flow resistance to the fluid flowing in the heat transfer tube is increased, the residence time of the fluid trying to pass through the heat transfer tube at a high speed is lengthened, and the contact frequency between the fluid and the fin member is increased. Therefore, heat exchange between the internal and external fluids via the heat transfer tube can be performed efficiently.
[0023]
In addition, in the heat transfer tubes of the conventional inventions such as Patent Documents 1 to 3, it is difficult to obtain heat transfer tubes having various heat exchange performances according to the purpose of use or budget by forming a plurality of fin members for each heat transfer tube. The cost was high due to the need for a simple manufacturing technique. However, as described above, the heat transfer tube of the present invention can easily obtain a plurality of types of heat transfer tubes having different heat exchange performances by simply changing the number of fin members inserted in the raw tube. That is, even when the same pipe and fin member are used, the heat transfer area can be greatly increased if a large number of fin members are inserted and arranged closely or narrowly in the pipe. Further, separation of the boundary layer due to fluid turbulence and frequency of contact between the plate fins and the fluid increase, and a heat transfer tube with higher heat exchange can be obtained. Therefore, it is suitable for cooling high-temperature EGR gas or heat exchange of a fluid having a high flow rate.
[0024]
Conversely, if the number of fin members arranged in the raw tube is reduced, the heat transfer area is reduced compared to the dense heat transfer tube of the fin member shown above, but in the case of a conventional heat transfer tube, heat transfer is reduced. The area can be increased. Furthermore, due to separation of the boundary layer due to fluid turbulence, good heat exchange performance can be obtained, and pressure loss of the fluid can be reduced, and a lighter and cheaper heat transfer tube can be obtained. . Therefore, it is suitable for a case where the flow pressure of the fluid is low and the flow rate is low, or for a fluid with a small amount of heat exchange.
[0025]
In addition, if a plurality of plate-like fins of the fin member are provided with through holes or long rugged strips, the surface area of the fin member can be increased, and the heat transfer area of the heat transfer tube can be further increased. Turbulence of the fluid flowing inside the heat pipe is further promoted or a fluid stirring action occurs, separation of the boundary layer is promoted, and heat exchange efficiency of the internal and external fluids through the heat transfer pipe can be increased. . Further, providing the metal material with the ridges and through holes can be easily performed by press working or the like, and does not affect the productivity of the heat transfer tube.
[0026]
Further, the heat transfer tube can be used in any device that exchanges heat, such as an automobile engine, other internal combustion engines, and air conditioning. And if the heat exchanger tube of this invention is assembled | attached to the EGR gas cooling device of an engine, and another multi-tube heat exchanger, cooling of EGR gas can be performed efficiently. Therefore, in an EGR system, particularly a cooled EGR system with a high EGR rate of a diesel engine, NOx in the exhaust gas can be reduced and fuel consumption can also be prevented from deteriorating. In addition, it is possible to prevent an excessive increase in temperature and to surely prevent the EGR valve from deteriorating and functioning.
[0027]
Also, the heat transfer tube of the present invention may be installed in an oil cooler built in a radiator that circulates high-temperature oil inside and cools with engine cooling water, and performs excellent heat exchange and heat transfer characteristics. High oil cooler can be obtained.
【Example】
[0028]
Hereinafter, an embodiment in which the heat transfer tube of the present invention is used in an EGR gas cooling apparatus in a cooled EGR system of an automobile will be described in detail with reference to the drawings. FIG. 1 is a perspective view of the heat transfer tube of the first embodiment, in which fin members each having four plate-like fins projecting inward are inserted into a plurality of metal base tubes at intervals. is there. FIG. 2 is a perspective view before the fin member of the first embodiment is formed into a cylindrical shape, and four plate-like fins having the same shape are projected from the substrate. FIG. 3 is a perspective view of the heat transfer tube of the second embodiment, in which two types of plate-like fins having different formation heights are alternately projected, and a total of eight plate-like fins are provided inward. Are arranged in a metal base tube at intervals. FIG. 4 is a perspective view before the fin member of the second embodiment is formed into a cylindrical shape, and eight plate-like fins having different formation heights are alternately provided on the substrate.
[0029]
FIG. 5 is a perspective view of the fin member of the third embodiment before being formed into a cylindrical shape, and four plate-like fins provided with corrugated ridges on both surfaces are projected from the substrate. FIG. 6 is a perspective view of the fin member before being formed into a cylinder of the fourth embodiment, in which four plate-like fins provided with a plurality of through holes are projected from the substrate. FIG. 7 is a schematic view of an EGR gas cooling device using the heat transfer tube of the present invention.
[0030]
The first embodiment of the present invention will be described in detail with reference to FIGS. 1, 2, and 7. A heat transfer tube (1) is a thin metal element through which EGR gas can flow. In the pipe (2), a plurality of metal fin members (4) with four plate-like fins (3) projecting inward in parallel with the pipe axis direction are inserted and arranged in series at intervals. Is formed.
[0031]
The raw tube (2) and the fin member (4) are made of copper, aluminum, brass, stainless steel or the like, so that they have excellent heat conductivity and corrosion resistance against EGR gas, condensate and the like ( 1) can be obtained. Note that the raw tube (2) and the fin member (4) may be formed of the same metal material, or depending on the purpose of use, cost, etc., as long as brazing or welding described below can be performed. Both may be formed of different metal materials.
[0032]
Further, in order to further enhance the reliability of the corrosion resistance of the heat transfer tube (1), a single layer of sacrificial corrosiveness composed of zinc, copper, tin, tin-zinc alloy, nickel, zinc-nickel alloy, etc., on the metal material as described above. 2 or more layers, such as plating the outer surface of the metal material and plating a zinc-nickel alloy on the outer peripheral surface of the nickel. Plating treatment may be performed. It is also possible to use a mass-produced blank tube (2) or a metal plate for the fin member (4) that has been subjected to these plating treatments in advance, eliminating the need for production such as plating treatment, and heat transfer tubes. Productivity can be improved.
[0033]
In order to manufacture the heat transfer tube (1), first, as the fin member (4), a rectangular substrate (5) is formed using the flat plate made of the metal material. The substrate (5) is formed in the longitudinal direction. The length is formed slightly shorter than the circumferential length of the inner peripheral surface of the element tube (2). Then, as shown in FIG. 2, four plate-like fins (3) that are parallel to both sides in the width direction of the substrate (5) and orthogonal to one surface of the substrate (5) are provided on one surface of the substrate (5). The fin member (4) is formed by protruding in parallel with each other. The four plate-like fins (3) are arranged so that the plate-like fins (3) radiate radially inward from the inner peripheral surface of the substrate (5) when the substrate (5) is cylindrical as described later. 3) is provided on the substrate (5) so as to protrude, and the entire one end surface of each plate-like fin (3) is disposed in surface contact with the surface of the substrate (5).
[0034]
Further, the plate-like fin (3) and the substrate (5) are brazed to improve the fixing property of the plate-like fin (3), and surface contact between the plate-like fin (3) and the substrate (5) is improved. To be sure, the thermal conductivity of both is increased. Further, by this brazing, the heat conduction area between the plate-like fin (3) and the substrate (5) is not only the contact area corresponding to the thickness of the plate-like fin (3) but also the thickness of the fillet of the brazing material. The area can be increased, and the thermal conductivity between the plate-like fin (3) and the substrate (5) can be further increased. In brazing, a brazing material may be plated on one or both of the contact surfaces of the plate-like fin (3) and the substrate (5), or the plate-like fin (3) and the substrate (5) may be plated. It may be performed by plating a brazing material on the whole, or by another method. Further, instead of brazing, the plate-like fins (3) and the substrate (5) may be connected and fixed by welding, and the structure of the fin member (4) is simple. In either case, the work can be easily performed.
[0035]
Next, the substrate (5) of the fin member (4) as shown in FIG. 2 has an outer diameter substantially the same as the inner diameter of the base tube (2), with one surface on which the plate-like fins (3) are projected inward. Mold into a cylindrical shape. A plurality of fin members (4) having a cylindrical shape are inserted and arranged in series at intervals in the raw pipe (2). By the way, since the fin member (4) has a length in the longitudinal direction of the substrate (5) slightly shorter than the circumferential length of the inner peripheral surface of the blank tube (2), The outer diameter of the fin member (4) that is cylindrical by attaching a pair of both end edges is slightly smaller than the inner diameter of the raw tube (2). Therefore, by inserting the fin member (4) into the raw pipe (2) in a state where the diameter is smaller than that of the raw pipe (2), the inserting and arranging operation can be performed smoothly and easily. Further, after the insertion and arrangement, the restoring force of the substrate (5) acts, and the outer diameter of the fin member (4) is expanded, so that the outer peripheral surface of the fin member (4) is moved into the inner tube (2). It can be tightly fixed to the peripheral surface, and the fixing property of the fin member (4) in the raw pipe (2) can be obtained.
[0036]
And in order to improve this fixability further, the inner peripheral surface of an elementary pipe (2) and the outer peripheral surface of the fin member (4) which adhere | attaches this are connected and fixed by welding or brazing. By improving the fixing property of the fin member (4) to the raw tube (2), the plate-like fin (3) is shaken or deformed due to the flow of EGR gas or the vibration of the heat transfer tube (1). 3) Suppress the fretting of the wall surface of the substrate (5) in contact with the substrate (5) and the base tube (2) with which the substrate (5) is in contact, and improve the usability and durability of the heat transfer tube (1). It becomes possible to improve. Further, even when a slight gap is generated between the outer peripheral surface of the substrate (5) of the fin member (4) and the inner peripheral surface of the raw tube (2), the brazing material or the melted metal material is left in the gap. Since it enters and closes the gap, it is possible to improve the thermal conductivity and fixability between the plate-like fin (3) and the raw tube (2).
[0037]
Further, when the fin member (4) and the raw pipe (2) are connected and fixed by brazing, before the fin member (4) is inserted into the raw pipe (2), the substrate of the fin member (4) ( 5) At least the long side edges of 5) or the entire outer surface of the substrate (5) is plated with a brazing material. The plating of the brazing material may be performed on the entire surface of the fin member (4), that is, the entire surface of the substrate (5) and the plate-like fin (3), because the work is preferably easy. A brazing material may be plated on the inner peripheral surface of (2). Further, the fin member (4) may be formed by cladding a brazing material on a metal plate which is a forming material of the fin member (4) and processing the clad material.
[0038]
Further, after inserting the fin member (4) coated with the binder for adhering the brazing material on both side edges of the substrate (5) into the raw tube (2), the powdery brazing material is supplied into the raw tube (2). May be. As another brazing means, the fin member (4) supplied with the brazing paste on both side edges in the longitudinal direction of the substrate (5) may be inserted into the raw tube (2), or in the raw tube (2). After inserting the fin member (4), a brazing paste may be supplied into the raw tube (2). And it may braze at the time of manufacture of a heat exchanger tube (1), or may braze after attaching a heat exchanger tube (1) to the below-mentioned EGR gas cooling device (10).
[0039]
In the heat transfer tube (1) formed as described above, a plurality of fin members (4) having four plate-like fins (3) projecting inward are provided to increase the heat transfer area, thereby increasing the heat transfer tube (1). The heat of the EGR gas flowing through the internal space (6) can be efficiently transferred not only to the inner surface of the base tube (2) but also to the plate fins (3). Further, the heat transferred to the plate-like fin (3) is transferred to the substrate (5) on which the plate-like fin (3) comes into surface contact, and then the contact between the substrate (5) and the raw tube (2). It is transmitted to the inner surface of the elementary tube (2) through the surface. Then, heat from these EGR gases is efficiently radiated to the refrigerant liquid flowing outside through the outer surface of the raw tube (2).
[0040]
In addition, the plurality of plate-like fins (3) project into the internal space (6), which is the EGR gas flow path, to generate turbulent flow in the EGR gas, and the fin member (4) is disposed. The boundary layer at the position can be peeled off to promote heat exchange between the EGR gas and the refrigerant liquid via the heat transfer tube (1). Further, in the present embodiment, a plurality of fin members (4) are arranged in the raw tube (2) with a space therebetween. Therefore, the cross-sectional area of the internal space (6) is reduced by the thickness of the substrate (5) at the position where the fin member (4) is disposed, and the internal space (6) is disposed at the position where the fin member (4) is not disposed. The cross-sectional area of is restored to a large area.
[0041]
Thus, when the EGR gas flowing inside the heat transfer tube (1) flows out from the narrow space to the wide space, the turbulence of the flow of the EGR gas is promoted, and a large number of flow vortices are generated. And since the vortex of this flow flows on the inner surface side of the raw pipe (2), the boundary layer of the EGR gas becomes thin even in the non-arranged portion of the fin member (4), and the EGR gas and the raw pipe ( The thermal conductivity with 2) is improved. Since a plurality of fin members (4) are arranged in the raw pipe (2) with a space therebetween, turbulence can be generated by the above-described flow throttling action and restoration of the internal space (6) to a large area. Repeatedly, the thermal conductivity is improved over the entire length of the heat transfer tube (1).
[0042]
Accordingly, heat exchange between the EGR gas flowing in the internal space (6) of the heat transfer tube (1) and the refrigerant liquid flowing outside the heat transfer tube (1) is promoted, and the temperature efficiency is improved and the heat transfer tube (1 ), The entire EGR gas flowing through the inner surface side and the center side is uniformly cooled or heated without unevenness. In addition to improving the temperature efficiency, the flow rate of the EGR gas flowing in the heat transfer tube (1) does not deteriorate, and the pressure loss of the fluid due to flowing in the heat transfer tube (1) can be prevented well. Can do. Furthermore, by the turbulent flow of EGR gas, the peeling of the soot adhering to the inner surface of the raw tube (2) is also promoted, and the decrease in thermal conductivity can be satisfactorily suppressed.
[0043]
The EGR gas cooling device (10) assembled with the heat transfer tube (1) as described above has a pair of tube sheets (12) connected to both ends of the cylindrical body tube (11) as shown in FIG. The inside can be sealed. And between the pair of tube sheets (12), a plurality of the heat transfer tubes (1) of the present embodiment are connected through the tube sheet (12). A pair of bonnets (16) are connected to both ends of the trunk pipe (11), and an EGR gas inlet (14) and outlet (15) are provided at the center of each bonnet (16).
[0044]
Furthermore, the outer periphery of the trunk tube (11) is partitioned by a pair of tube sheets (12) by providing an introduction passage (17) and an outlet passage (18) for a cooling medium such as engine cooling water and cooling air. A heat exchange section (13) through which a cooling medium can flow is used in the airtight space. Further, a plurality of support plates (20) are joined and arranged in the heat exchange section (13), and the heat transfer tube (1) is inserted into the insertion hole (21) provided in the support plate (20). The heat transfer tube (1) is stably supported as a baffle plate, and the flow of the cooling medium flowing in the heat exchange section (13) is meandered.
[0045]
In the EGR gas cooling device (10), when EGR gas having a high temperature is introduced into the trunk pipe (11) from the exhaust manifold side through the inlet (14), the EGR gas is introduced into the trunk pipe (11). ) Flows into the heat transfer tubes (1) arranged in a plurality. In the heat exchange section (13) in which the heat transfer tube (1) is arranged, a cooling medium such as engine cooling water is circulated in advance outside the heat transfer tube (1). Thus, heat exchange is performed between the EGR gas and the cooling medium.
[0046]
As described above, the heat transfer tube (1) increases the heat transfer area by disposing the fin member (4), and at the same time, reduces the flow of EGR gas and reduces the internal space (6) to a large area. By causing gas turbulence, the thermal conductivity between the fin member (4) and the element pipe (2) is enhanced. Therefore, not only the heat of the EGR gas on the inner surface side of the raw pipe (2) but also the heat of the EGR gas flowing near the center is transferred to the inner surface of the raw pipe (2) via the fin member (4). Then, heat is radiated to the cooling medium through the outer surface of the base tube (2), and an excellent cooling effect on the EGR gas is obtained as compared with the conventional case.
[0047]
The EGR gas thus well cooled flows out of the EGR gas cooling device (10) through the outlet (15) and is returned to the intake manifold side. Accordingly, it is possible to prevent the EGR valve from being heated to high temperature and obtain the excellent functionality and durability of the EGR valve, and to reduce the temperature of the intake air, so that NOx can be reduced and good fuel consumption can be achieved. Moreover, the turbulent flow of the EGR gas in the heat transfer tube (1) promotes the separation of soot mixed in the EGR gas and prevents it from becoming a large lump, and the cooling performance due to clogging etc. It is possible to prevent deterioration and engine trouble.
[0048]
As described above, in the EGR gas cooling device (10) provided with a plurality of heat transfer tubes (1) having the same shape according to the present invention, an excellent cooling effect on the EGR gas can be obtained. However, in the EGR gas cooling device (10), the EGR gas flowing into the device is introduced into the trunk tube (11) having a large cross-sectional area from the inlet (14) and diffused outwardly while the heat transfer tube (1). ) Flow in the direction. Therefore, the EGR gas is in a high pressure state near the center of the trunk tube (11) and easily flows into the heat transfer tube (1) near the center at a high speed, but as the distance from the inlet (14) increases, Since the pressure of the EGR gas is lower and the flow rate is slower than the vicinity of the center, the EGR gas hardly flows into the heat transfer tube (1) arranged outside. As a result, the heat transfer tube (1) near the center in the trunk tube (11) has a large amount of exchange heat and efficient heat exchange is performed, but the amount of exchange heat in the heat transfer tube (1) decreases with increasing distance from the center, In some cases, the excellent heat exchange function of the EGR gas cooling device (10) cannot be fully exhibited.
[0049]
In order to solve this problem, a plurality of heat transfer tubes (1) having different flow resistances to the EGR gas are formed, and the EGR gas in the body tube (11) of the EGR gas cooling device (10) as shown in FIG. Corresponding to the difficulty of inflow, a heat transfer tube (1) having a different flow resistance is provided. By arranging such a heat transfer tube (1), the EGR gas can be uniformly passed through all the heat transfer tubes (1) in the trunk tube (11), and the EGR gas can be efficiently cooled. To do.
[0050]
The adjustment of the flow resistance may be performed by increasing or decreasing the number of plate-like fins (3) of the fin member (4), but in this embodiment, the fin member (4) inserted and disposed in the raw tube (2). The flow resistance to the EGR gas of the heat transfer tube (1) is adjusted by increasing or decreasing the number of the tubes. In the vicinity of the center of the trunk pipe (11) close to the inlet (14), the pressure of the EGR gas is high and easily flows into the heat transfer pipe (1), so the number of fin members (4) inserted is increased, A heat transfer tube (1) having increased flow resistance to the fluid is provided. Further, the further away from the EGR gas inlet (14), the lower the pressure of the EGR gas and the less likely it is to flow into the heat transfer tube (1). ) Are inserted, and the heat transfer tubes (1) each having a reduced flow resistance are disposed.
[0051]
In the EGR gas cooling device (10) in which the heat transfer tube (1) is disposed as described above, when EGR gas is first introduced from the inlet (14) into the bonnet (16) having a large cross-sectional area, Mostly, it flows into the heat transfer tube (1) arranged near the center of the trunk tube (11) and tries to pass at high speed. However, since the heat transfer tube (1) near the center has a large number of fin members (4), the flow resistance to the EGR gas is large, and the inflow amount of EGR gas to the heat transfer tube (1) is limited. Is done. Since the inflow of EGR gas to the heat transfer tube (1) near the center is restricted, the EGR gas flows radially in the bonnet (16), and the outer side away from the inlet (14) The EGR gas easily flows into the heat transfer tube (1). Therefore, EGR gas can be made to flow more uniformly into all the heat transfer tubes (1) in the trunk tube (11).
[0052]
And in the heat exchanger tube (1) arrange | positioned near the center of the trunk tube (11), since many fin members (4) are equipped internally, a heat-transfer area can be increased greatly and plate-shaped fin (3 ), The contact frequency between the EGR gas and the plate fin (3) can be increased. In addition, the thermal conductivity of the heat transfer tube (1) is improved by the separation of the boundary layer due to the turbulent flow of EGR gas, and the heat exchange between the EGR gas and the cooling medium through the heat transfer tube (1) is efficient. Can be done.
[0053]
On the other hand, in the heat transfer tube (1) disposed outside the trunk tube (11), the number of fin members (4) inserted is reduced to reduce the flow resistance of the EGR gas. ) EGR gas flowing in the inside can be flowed with little pressure loss. Even if the number of inserted fin members (4) is small, the presence of the fin member (4) can increase the heat transfer area compared to the conventional case, and the fin member (4) and the raw tube (2) Excellent thermal conductivity. Further, the turbulent flow of EGR gas is caused by the flow throttling effect at the position where the fin member (4) is disposed and the restoration of the internal space (6) to a large area at the position where the fin member (4) is not disposed. The heat transfer is improved over the entire length of the heat transfer tube (1). Therefore, even in the heat transfer tube (1) disposed outside, the amount of heat exchanged between the EGR gas and the refrigerant liquid is large, and the heat exchange function as the heat transfer tube (1) can be sufficiently exhibited.
[0054]
As described above, in any heat transfer tube (1) disposed in the trunk tube (11), the heat exchange between the EGR gas and the refrigerant liquid is performed efficiently, so that the EGR gas cooling device (10). Thus, the entire EGR gas introduced into is cooled evenly, and a high-performance EGR gas cooling device (10) capable of sufficiently exhibiting heat exchange performance can be obtained.
[0055]
In the heat transfer tube of the prior art, a long spiral fin member from one end to the other end of the raw tube is disposed, or a flat fin member is projected inward by folding the wall surface of the raw tube is doing. Therefore, when forming multiple types of heat transfer tubes with different fluid flow resistances as described above, the number of fin members can be increased by changing the helical pitch of the fin members or by increasing the number of times the raw tube is folded. It is necessary to do so, and it is difficult to implement due to labor and cost for production. However, in the present invention, as described above, it is possible to easily form the heat transfer tubes (1) having different flow resistances by simply changing the number of fin members (4) inserted and arranged in the raw tube (2). The fin member (4) can be mass-produced with the same shape. Moreover, since the disposing operation of the fin member (4) to the raw tube (2) can be easily performed without requiring a high-level manufacturing technique, the heat transfer tube (1) of the present invention is Inexpensive implementation becomes possible.
[0056]
Further, in the heat transfer tube (1) of the first embodiment, the fin members (4) disposed in the base tube (2) are four pieces having the same shape in the axial center direction from the inner peripheral surface of the substrate (5). In the heat transfer tube (1) of another different second embodiment, as shown in FIG. 3, eight fins (4) having different formation heights are provided. A plate-like fin (3) is projected. In order to form such a fin member (4), as shown in FIG. 4, the substrate (5) whose length in the longitudinal direction is slightly shorter than the circumferential length of the inner peripheral surface of the raw tube (2). 4 plate fins (3) having the same shape as the first embodiment, and four plate fins (3) having the same formation width and formation length but low formation height Are alternately connected and fixed at intervals. A plurality of fin members (4) obtained by forming the substrate (5) provided with the plate-like fins (3) having a difference in height into a cylindrical shape are inserted into the base tube (2) at intervals. It is arranged.
[0057]
Also in this case, the work is facilitated by inserting the fin member (4) while reducing the outer diameter so as to be smaller than the inner diameter of the element pipe (2). And after arrangement | positioning completion, since the outer peripheral surface of a fin member (4) is elastically contact | adhered and fixed to the inner peripheral surface of a raw tube (2) with the restoring force of a board | substrate (5), Fixability is obtained. Further, the plate-like fins (3) of each fin member (4) and the substrate (5), and the outer peripheral surface of the substrate (5) and the inner peripheral surface of the raw tube (2) are connected by welding, brazing, or the like. By this, it becomes possible to improve the fixing property and thermal conductivity between the fin member (4) and the raw tube (2).
[0058]
In the heat transfer tube (1) of the second embodiment formed as described above, the heat transfer tube (1) is provided by installing a fin member (4) projecting eight plate-like fins (3) having a height difference. The heat transfer area can be further increased, and the turbulent flow of the EGR gas is further promoted. And the heat | fever of EGR gas can be efficiently transmitted to a raw pipe | tube (2) via a fin member (4). Further, the turbulent flow of EGR gas is caused by the flow throttling effect at the position where the fin member (4) is disposed and the restoration of the internal space (6) to a large area at the position where the fin member (4) is not disposed. The heat transfer performance is improved over the entire length of the heat transfer tube (1). Therefore, it is possible to efficiently perform heat exchange between the EGR gas and the cooling medium via the heat transfer tube (1).
[0059]
Moreover, in the said 1st, 2nd Example, the formation length of the longitudinal direction of the board | substrate (5) of a fin member (4) is made slightly short rather than the circumferential length of the internal peripheral surface of a raw tube (2). Therefore, when the outer peripheral surface of the fin member (4) is closely fixed to the inner peripheral surface of the element pipe (2) by elastic restoring force, as shown in FIGS. A gap is created between the both ends of each other. Even if such a gap is generated, since the outer peripheral surface of the fin member (4) and the inner peripheral surface of the raw pipe (2) are connected and fixed by brazing or welding, there is no problem in fixing property, It is also possible to close this gap by filling with a brazing material or a metal material.
[0060]
Here, as another different embodiment, the formation length of the substrate (5) in the longitudinal direction of the fin member (4) may be formed substantially the same as the circumferential length of the inner peripheral surface of the base tube (2). . Even with such a fin member (4), the substrate (5) is only curved and formed into a cylindrical shape, and therefore, by laminating both sides in the width direction of the substrate (5), the fin member (4) The diameter can be reduced to be smaller than the inner diameter of the raw tube (2), and the insertion work into the raw tube (2) can be easily performed. After completion of the insertion and arrangement, the outer peripheral surface of the fin member (4) is firmly fixed to the inner peripheral surface of the raw tube (2) by the restoring force of the substrate (5), and the fin member (4) in the width direction is mutually fixed. Both end edges of the fins come into contact with each other without generating a gap, so that not only a stable fixing property of the fin member (4) is obtained, but also the appearance is good.
[0061]
In the heat transfer tubes (1) of the first and second embodiments, the surface of the plate-like fin (3) is smooth without any irregularities such as corrugations or through-holes, but is different. In the third embodiment, as shown in FIG. 5, a plurality of corrugated ridges (7) parallel to the tube axis direction are provided on both surfaces of the plate fin (3). The formation of the ridges (7) can further increase the heat transfer area of the fin member (4), improve the thermal conductivity of the heat transfer tube (1), and obtain excellent heat exchange performance. it can. Moreover, such an uneven | corrugated strip (7) can be easily provided also with a metal material by press work etc., and manufacture of a heat exchanger tube (1) becomes easy.
[0062]
In another different fourth embodiment shown in FIG. 6, a plurality of circular through holes (8) are opened in the plate-like fin (3). Such an opening of the through hole (8) can further increase the heat transfer area of the fin member (4), and a fluid such as EGR gas passes through the through hole (8), thereby turbulent flow. Will occur. Further, the fin member (4) has more edge portions, further promoting the turbulent flow of the fluid, and can improve the heat conduction efficiency by peeling the boundary layer, and the heat transfer tube (1 ) Can be obtained. Moreover, the opening work of this through-hole (8) can also be easily performed by press work etc. Further, the through hole (8) may be opened in a shape such as an ellipse, an oval, a triangle, a quadrangle, and other polygons, instead of a circle.
[0063]
In the first to fourth embodiments, a plurality of plate-like fins (3) protruding from the substrate (5) are arranged in parallel with both sides in the width direction of the substrate (5) to form a plate-like shape. The fin (3) is arranged in parallel to the fluid flow direction. However, as another different embodiment, the plate-like fins (3) are arranged with respect to the fluid flow direction by arranging the plate-like fins (3) obliquely with respect to the both sides in the width direction of the substrate (5). ) May be tapered. Further, by providing the substrate (5) with the plate-like fins (3) curved in an arc shape in the width direction, the plate-like fins (3) may be arranged in an arc shape with respect to the fluid flow direction. good. Moreover, the front end side of the plate-like fin (3) may be formed in an arc shape in the direction of the substrate (5), or may be twisted in an oblique direction. In the third embodiment, the corrugated ridges (7) of the plate fin (3) are parallel to the tube axis direction, that is, the width direction, but parallel to the height direction of the plate fin (3). A wavy uneven strip (7) may be provided. Moreover, you may provide a rectangular fin, V shape, other uneven | corrugated strips (7), etc. in a plate-shaped fin (3).
[0064]
In each of the above embodiments, the EGR gas cooling device (10) is described as being assembled with the heat transfer tube (1) of the present invention. However, the heat transfer tube of the present invention is applied to another different multi-tube heat exchanger. A heat pipe (1) may be used, and excellent heat exchange performance can be obtained. In addition, the heat transfer tube (1) of the present invention is used in a built-in oil cooler for a radiator that circulates high-temperature oil such as engine oil, mission oil, ATF, power steering oil, etc., and cools this high-temperature oil with engine cooling water. ) Can also be assembled. And the engine cooling water which distribute | circulates the inside of a heat exchanger tube (1), and the to-be-cooled oil which distribute | circulates the exterior of a heat exchanger tube (1) through the heat exchanger tube (1) with a wide heat-transfer area of this invention and high heat conductivity Heat exchange with the oil is promoted, and the oil to be cooled can be cooled uniformly and efficiently.
【The invention's effect】
[0065]
The present invention is configured as described above, and a plurality of metal fin members having a plurality of plate-like fins projecting inward are arranged in a metal base tube excellent in thermal conductivity. The heat transfer area of the heat transfer tube can be increased. In addition, the projection of the plate fins promotes the turbulent flow of the fluid flowing in the heat transfer tube, peels off the boundary layer that is likely to be generated near the inner surface of the elementary tube, and the inner and outer sides through the heat transfer tube. Heat exchange of fluid can be promoted, and a heat transfer tube with high heat exchange performance can be obtained.
[0066]
In addition, it is possible to simply manufacture a plurality of fin members formed by forming a cylindrical board on which a plate-like fin is formed into a cylinder, and to provide a product with excellent heat exchange performance at a low price. Is possible. Furthermore, the heat exchange performance of the heat transfer tube can be adjusted by adjusting the number of fin members inserted into the raw tube. And by using this heat transfer tube excellent in heat exchange performance for a multi-tube heat exchanger, a radiator built-in oil cooler, etc., a product with high heat transfer characteristics can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a heat transfer tube according to a first embodiment of the present invention.
FIG. 2 is a perspective view of the fin member of the first embodiment, showing a state in which four plate-like fins are projected from a substrate.
FIG. 3 is a perspective view showing a heat transfer tube according to a second embodiment of the present invention.
FIG. 4 is a perspective view of a fin member according to a second embodiment, showing a state where eight plate-like fins having different formation heights are projected from a substrate.
FIG. 5 is a perspective view of a fin member according to a third embodiment, showing a state where four plate-like fins provided with concave and convex stripes on both surfaces are projected from a substrate.
FIG. 6 is a perspective view of a fin member according to a fourth embodiment, showing a state in which four plate-like fins provided with a plurality of through holes are projected from a substrate.
FIG. 7 is a partially cutaway plan view of an EGR gas cooling apparatus in which the heat transfer tube of the present invention is assembled.
[Explanation of symbols]
2 Elementary tube
3 plate fins
4 Fin members
5 Substrate
7 Uneven strip
8 Through hole

Claims

A cylindrical fin member formed by projecting a plurality of plate fins in parallel to one surface of a metal substrate and bending the substrate into a cylindrical shape with the plate fins inside. , inserted disposed a plurality series containing tube made of metal, the outer peripheral surface of a substrate on which a cylindrical fin member, the inner and Rutotomoni plate fins blank tube is closely fixed to the inner peripheral surface of the base pipe Further, a heat transfer tube having a fin member, which is provided so as to protrude radially in the tube axis direction and is arranged through a fluid flow interval without contacting the tip in the protruding direction of the plate fin .

2. A heat transfer tube having a fin member as claimed in claim 1, wherein a plurality of fin members are inserted and disposed in the raw tube with close contact or spacing.

The plate-like fin is provided with a through-hole or a long uneven strip, and the heat transfer tube having the fin member according to claim 1 installed therein.