JP2004277820A

JP2004277820A - High frequency induction heating method for crankshaft and its apparatus

Info

Publication number: JP2004277820A
Application number: JP2003071225A
Authority: JP
Inventors: Seiichi Sawatsubashi; 精一沢津橋; Keiichi Kubo; 啓一久保
Original assignee: Denki Kogyo Co Ltd
Current assignee: DKK Co Ltd
Priority date: 2003-03-17
Filing date: 2003-03-17
Publication date: 2004-10-07
Anticipated expiration: 2023-03-17
Also published as: JP4209227B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency induction heating method for crankshaft and its apparatus with which the outer peripheral surface of a pin part or a journal part in the crankshaft can uniformly be heated over the entire periphery in a short period of time and therefor, a good (uniform) hardened layer pattern can be obtained by eliminating the inequality of the hardened layer depth. <P>SOLUTION: Heating coil portions 14a, 14b or 29 of the plurality of high frequency induction heating coils 11a, 11b or 30a, 30b oppositely disposed so as to separate a few gap to the outer peripheral surfaces S or H of the pin part 3 or the journal part 2 of the crankshaft 1 are disposed to mutually offsetting positions in the directions to the center axes Y or X of the pin part 3 or the journal part 2 of the crankshaft 1 to perform the high frequency induction heating. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、クランクシャフトのピン部又はジャーナル部の外周面（円筒状外周面及びその両側の湾曲状隅部を含む）を焼入処理や焼戻処理などのために高周波誘導加熱する高周波誘導加熱方法及び装置に関するものである。
【０００２】
【従来の技術】
図５は、４気筒エンジン用クランクシャフト１を示すものであって、このクランクシャフト１は、中心軸Ｘ（ジャーナル部の軸線と同じ）を軸心とするジャーナル部２ａ，２ｂ，２ｃ，２ｄ，２ｅと、中心軸Ｘに対して偏心した位置にあるピン部３ａ，３ｂ，３ｃ，３ｄと、カウンターウエイト部４ａ，４ｂ，４ｃ，４ｄ，４ｅ，４ｆ，４ｇ，４ｈと、フランジ部５とを鍛造加工により一体に成形して成るものである。複数気筒エンジン用クランクシャフトであればピン部３は複数設けられ、図５に示す４気筒エンジン用クランクシャフト１の場合には、４つのピン部３ａ〜３ｄが設けられる。そして、これらのピン部３ａ〜３ｄは、中心軸Ｘの軸線方向に沿って所定の間隔を隔てた箇所において、互いに隣接するカウンターウエイト部４の間にそれぞれ配置される。また、中心軸Ｘの軸線方向において互いに隣接する各ピン部３ａ〜３ｄは、エンジンの形式に応じて、中心軸Ｘの回りに所定の位相角度だけ異なる角度位置に配設される。なお、図５に示す４気筒エンジン用クランクシャフト１の場合には、左右両端側のピン部３ａ，３ｄ（中心軸Ｙ_１を有する）が互いに同じ位相角度の箇所に配設されると共に、これらのピン部３ａ，３ｄ間のピン部３ｂ，３ｃ（中心軸Ｙ_２を有する）が互いに同じ位相角度の箇所に配設され、左右両端側のピン部３ａ，３ｄと中間位置のピン部３ｂ，３ｃとが互いに１８０度の位相角度をもって配設される。
【０００３】
この種のクランクシャフト１にあっては、従来より、クランクシャフト１のジャーナル部２ａ〜２ｅ及びピン部３ａ〜３ｄの外周面にそれぞれ高周波誘導加熱による焼入を施すことにより、耐摩耗性並びに疲労強度の向上を図るようにしている。ここで、クランクシャフト１のピン部３ａ〜３ｄ（以下においては、統括的にピン部３と記載する）を高周波誘導加熱する場合を例にとって説明すると、次の通りである。
【０００４】
図６は、ピン部３の外周面Ｓを焼入処理に際して高周波誘導加熱するために従来より用いられている高周波誘導加熱装置８を示すものである。この高周波焼入装置８は、図６に明示するように、真鍮製又は樹脂製の一対の側板１０ａ，１０ｂ間に挟持状態で保持され、かつ、クランクシャフト１の中心軸Ｘを中心に回転駆動されるピン部３の外周面Ｓの上半分部分に対向配置される半開放鞍型の高周波誘導加熱コイル（半開放鞍型コイル）１１と、この高周波誘導加熱コイル１１に高周波電流を供給する高周波電源１２と、前記一対の側板１０ａ，１０に固定された例えば３つのセラミック製又は超硬合金製のガイド部材（チップ部材）１３ａ，１３ｂ，１３ｃとを備えている。
【０００５】
上述の高周波誘導加熱コイル１１は、図６及び図７に示すように、コイル頭部を構成する左右一対の第１及び第２の加熱コイル部分１４ａ，１４ｂと、これらの一対の加熱コイル部分１４ａ，１４ｂとを互いに接続する接続導体部１５ａ，１５ｂ，１５ｃと、一対の接続導体部１５ａ，１５ｂにそれぞれ接続された給電リード部１６ａ，１６ｂとから成り、上述の給電リード部１６ａ，１６ｂが高周波電源１２に接続されている。なお、このような構造のコイル体としては、例えば特開２００１−１８１７３９号に開示されているものがある。ここで、高周波誘導加熱コイル１１の第１の加熱コイル部分１４ａについて詳述すると、この第１の加熱コイル部分１４ａは、図７に明示するように、互いに平行な一対の円弧状加熱導体部１７ａ，１８ａと、円弧状加熱導体部１７ａの一端と円弧状加熱導体部１８ａの一端とを互いに接続する直線状加熱導体部１９ａと、円弧状加熱導体部１７ａ，１８ａの他端と接続導体部１５ａ，１５ｃの一端とをそれぞれ接続する直線状加熱導体部２０ａ，２１ａとから構成され、全体として湾曲したほぼ矩形形状となされている。また、第２の加熱コイル部分１４ｂも上述の第１の加熱コイル部分１４ａと同様に構成され、一対の加熱コイル部分１４ａ，１４ｂが左右対称の配置関係をもって対応配置されている。なお、図７においては、第２の加熱コイル部分１４ｂの一対の円弧状加熱導体部１７ｂ，１８ｂ、直線状加熱導体部１９ｂ、接続導体部１５ａ，１５ｃ、及び給電リード部１６ｂが図示されているが、既述の直線状加熱導体部２０ａ，２１ａに相当する部分の直線状加熱導体部２０ｂ，２１ｂは、隠れた位置にあるため、図示されていない。
【０００６】
また、給電リード部１６ａ，１６ｂは、高周波電流供給用のトランス（図示せず）に接続され、このトランスには高周波電源２０から所定の高周波電流が供給されるように構成されている。
【０００７】
上述の高周波誘導加熱装置８によりクランクシャフト１のピン部３の外周面Ｓを焼入処理或いは焼戻処理などのために高周波誘導加熱するに際しては、図外の昇降機構により高周波誘導加熱装置８を所定の待機位置から下降移動させてガイド部材１３ｂを介してピン部３の外周面Ｓ上に載置し、ガイド部材１３ａ〜１３ｃをピン部３の外周面Ｓに当接せしめることにより高周波誘導加熱コイル１１をピン部３の外周面Ｓの上半分部分に対して僅かな間隔を隔てて対向配置する。この状態の下で、クランクシャフト１を図外の回転駆動機構によりクランクシャフト１の中心軸Ｘを中心に回転駆動する。これに伴い、ピン部３が前記中心軸Ｘを中心として公転運動する。この際、高周波誘導加熱装置８が図外の追従機構によりピン部３に追従すると共に、高周波誘導加熱コイル１１の第１及び第２の加熱コイル部分１４ａ，１４ｂが左右対称位置においてピン部３の外周面Ｓの上半分部分に対して常に対向配置された状態を維持する。
【０００８】
このような状態の下で、高周波電源１２から図外のトランス並びに給電リード部１６ａ，１６ｂ、接続導体部１５ａ，１５ｂを順次に介して高周波誘導加熱コイル１１の第１及び第２の加熱コイル部分１４ａ，１４ｂに高周波電流を供給し、これによりピン部３の外周面Ｓを誘導加熱する。次いで、ピン部３の外周面Ｓが所要の焼入温度に誘導加熱された時点で、高周波電源１２から高周波誘導加熱コイル１１への高周波電流の供給を遮断すると共に、ピン部３の外周面Ｓに焼入冷却水噴射手段（図示せず）により焼入冷却水を噴射する。これにより、ピン部３の外周面Ｓが急速冷却されてその表面に焼入硬化層が形成される。
【０００９】
また、図８は、別の形状の半開放鞍型の高周波誘導加熱コイル（半開放鞍型コイル）３０を備える従来の高周波誘導加熱装置３１を示すものである。この高周波誘導加熱装置３１は、図８に示すように、真鍮製又は樹脂製の一対の側板１０ａ，１０ｂ間に挟持状態で保持され、かつ、クランクシャフト１の中心軸Ｘを中心に回転駆動されるピン部３（ピン部３ａ〜３ｄ）の外周面Ｓの上半分部分に対向配置される１つの加熱コイル部分２９を有する高周波誘導加熱コイル３０を備えている。なお、その他の構成は、図６の高周波誘導加熱装置８と同様である。
【００１０】
上述の高周波誘導加熱コイル３０は、図８及び図９に示すように、コイル頭部）を構成する１つの加熱コイル部分２９と、この加熱コイル部分２９に接続された一対の給電リード部３２ａ，３２ｂとから成り、上述の給電リード部３２ａ，３２ｂが高周波電源１２に接続されている。なお、このような構造のコイル体の類似物としては、例えば特開平３−１８３７２４号に開示されているものがある。ここで、高周波誘導加熱コイル３０の加熱コイル部分２９の構成について詳述すると、この加熱コイル部分２９は、図９に明示するように、互いに平行な一対の円弧状加熱導体部３３ａ，３３ｂと、円弧状加熱導体部３３ａの一端と円弧状加熱導体部３３ｂの一端とを互いに接続する直線状加熱導体部３４と、円孤状導体部３３ａ，３３ｂの他端と給電リード部３２ａ，３２ｂの一端とをそれぞれ接続する直線状加熱導体部３５ａ，３５ｂとから構成されている。
【００１１】
そして、給電リード部３２ａ，３２ｂは、高周波電流供給用のトランス（図示せず）を介して高周波電源１２に接続されており、この高周波電源１２から所定の高周波電流が高周波誘導加熱コイル３０の加熱コイル部分２９に供給されるように構成されている。
【００１２】
なお、上述の高周波誘導加熱装置３１は、特に、ピン部３或いはジャーナル部２の直径が小さい小型のクランクシャフトを高周波誘導加熱するのに有効である。その理由を述べると、次の通りである。すなわち、図６の高周波誘導加熱装置８にあっては高周波誘導加熱コイル１１の頭部が２つの加熱コイル部分１４ａ，１４ｂに２分割されており、円弧状加熱導体部１７ａと１７ｂとが周方向で２つに分割されると共に円弧状加熱導体部１８ａと１８ｂとが周方向で２つに分割されているため、ピン部３ａ〜３ｄ或いはジャーナル部２ａ〜２ｅの直径が小さい場合には、円弧状加熱導体部１５ａ，１５ｂ及び１６ａ，１６ｂの弧長が相対的に短くなり加熱効率が悪くなるが、図８の高周波誘導加熱装置３１にあっては、高周波誘導加熱コイル３０の加熱コイル部分２９の円弧状加熱導体部３３ａ，３３ｂが２つに分割されていないので、ピン部３の外周面Ｓ（又はジャーナル部２の外周面Ｈ）に対向する円弧状加熱導体部３３ａ，３３ｂの弧長が上記の場合よりも相対的に長くなり、これに起因して加熱効率が向上するためである。
【００１３】
図８の高周波誘導加熱装置３１により、例えばクランクシャフト１のピン部３の外周面Ｓを焼入処理などのために高周波誘導加熱するに際しては、図外の昇降機構により高周波誘導加熱装置３１を所定の待機位置から下降移動させてガイド部材１３ａ〜１３ｃを介してピン部３の外周面Ｓ上に載置し、ガイド部材１５ｂをピン部３の外周面Ｓに当接せしめることにより高周波誘導加熱コイル３０をピン部３の外周面Ｓの上半分部分に対して僅かな間隔を隔てて対向配置する。この状態の下で、クランクシャフト１を図外の回転駆動機構によりクランクシャフト１の中心軸Ｘを中心に回転駆動する。これに伴い、ピン部３が前記中心軸Ｘを中心として公転運動する。この際、高周波誘導加熱装置３１が図外の追従機構によりピン部３に追従すると共に、高周波誘導加熱コイル３０の加熱コイル部分２９がピン部３の外周面Ｓの上半分部分に対して常に対向配置された状態を維持する。
【００１４】
このような状態の下で、高周波電源１２から図外のトランス並びに給電リード部３２ａ，３２ｂを順次に介して高周波誘導加熱コイル３０の加熱コイル部分２９に高周波電流を供給し、これによりピン部３の外周面Ｓを誘導加熱する。次いで、ピン部３の外周面Ｓが所要の焼入温度に誘導加熱された時点で、高周波電源１２から高周波誘導加熱コイル３０への高周波電流の供給を遮断すると共に、ピン部３の外周面Ｓに焼入冷却水噴射手段（図示せず）により焼入冷却水を噴射する。これにより、ピン部３の外周面Ｓが急速冷却されてその表面に焼入硬化層が形成される。
【００１５】
図１０（ａ）〜（ｃ）は、高周波誘導加熱コイル１１又は３０の断面形状の代表的な例、並びに、上述の如き焼入工程によりピン部３の外周面Ｓに得られる望ましい（理想的な）硬化層パターンＰ_１，Ｐ_２，Ｐ_３をそれぞれ示している。なお、図６（ａ）のようにピン部３の外周面（円筒状外周面）Ｓのみに焼入硬化層パターンＰ_１を形成する焼入は平焼入と称され、図６（ｂ）のようにピン部３の外周面Ｓからその両側のＲ部（円弧状隅部）Ｍに連なる焼入硬化層パターンＰ_２を形成する焼入はフィレットＲ焼入と称され、図６（ｃ）のようにピン部３の外周面Ｓから片側のＲ部Ｍ及びスラスト部（平面部）Ｎに連なる焼入硬化層パターンＰ_３を形成する焼入は片Ｒ焼入と通常呼ばれている。
【００１６】
【特許文献１】
特開２００１−１８１７３９号公報
【特許文献２】
特開平３−１８３７２４号公報
【００１７】
【発明が解決しようとする課題】
しかしながら、従来の高周波誘導加熱装置８（又は３１）により形成される焼入硬化層Ｐ_１，Ｐ_２，Ｐ_３は、図１１〜図１３に示すように焼入硬化層深さが不均一になる傾向がある。この理由を、以下に述べる。
【００１８】
まず、図１１（ａ）は、従来の高周波誘導加熱装置８の平焼入用の高周波誘導加熱コイル１１の断面（図６においてＤ−Ｄ線で破断した断面）を示す図である。図１１（ａ）に示すように、高周波誘導加熱コイル８の第１及び第２の加熱コイル部分１４ａ，１４ｂを構成する円弧状加熱導体部１７ａ，１８ａ，１７ｂ，１８ｂのうちの円弧状加熱導体部１７ａ及び１７ｂは、クランクシャフト１の中心軸Ｘに沿う方向において互いに同位置に配置されて前記ピン部３の外周面Ｓに対向されると共に、円弧状加熱導体部１８ａ及び１８ｂは、前記中心軸Ｘに沿う方向において互いに同位置に配置されてピン部３の外周面Ｓに対向されるため、前記中心軸Ｘを中心とするピン部３の公転運動中は、円孤状加熱導体部１７ａ及び１７ｂがピン部３の外周面Ｓに対応する位置であってかつピン部３の円周方向において同一の領域α_１を通過すると共に、円弧状加熱導体部１８ａ及び１８ｂがピン部３の外周面Ｓに対応する位置であってかつピン部３の円周方向において同一の領域α_２を通過することになる。
【００１９】
従って、ピン部３の外周面Ｓは、ピン部３の円周方向においてそれぞれ同一の領域である領域α_１及びα_２が集中的に加熱される一方、嶺域α_１，α_２間の領域βは、主に熱伝導に依って昇温されることとなる。このような不均一な加熱の結果として得られる焼入硬化層パターンＰは、図１１（ｂ）に示すように、前記加熱導体部１７ａ，１７ｂ及び１８ａ，１８ｂにそれぞれ対向する前記領域α_１及びα_２の部分における焼入硬化層深さが相対的に深く、円弧状加熱導体部１７ａと１８ａとの間、並びに、円弧状加熱導体部１７ｂと１８ｂとの間に対向する領域βの焼入硬化層深さが相対的に浅くなるような傾向が現れる。特に、焼入硬化層深さを浅くした場合や、加熱時間が短い場合には、そのような傾向が非常に顕著に現れる。
【００２０】
また、ピン部３の幅が広い場合には、第１及び第２の加熱コイル部分１４ａ，１４ｂの直線状加熱導体部１９ａ，１９ｂ，２０ａ，２０ａ，２１ｂ，２１ｂの長さが長くなり、加熱導体としてピン部３の外周面Ｓの中央近傍部分（幅方向中央箇所）の加熱に寄与するため、焼入硬化層深さの不均一は発生しにくい。しかし、幅狭のピン部３を加熱する場合には、前記直線状加熱導体部の長さが短くなり、一対の円弧状加熱導体部１７ａと１８ａ、１７ｂと１８ｂにより誘導加熱が行われるため、ピン部３の幅方向の中央近傍部分は誘導加熱されにくくなり、その結果、上述した短時間加熱による焼入硬化層パターンＰと同様の傾向が現れる。
【００２１】
なお、フィレットＲ焼入の場合（図１２（ａ），（ｂ）参照）、及び、片Ｒ焼入の場合（図１３（ａ），（ｂ）参照）に関しても、上記の理由により、同様の傾向が生じる。
【００２２】
さらに、高周波誘導加熱装置８の高周波誘導加熱コイル１１は、ピン部３の外周面Ｓの上側の略１／２周にのみ対向しているため、誘導加熱完了直後にピン部３の外周面Ｓのうち高周波誘導加熱コイル１１の第１及び第２の加熱コイル部分１４ａ，１４ｂが対向している上面側と開放側に位置する下面側とでは、焼入硬化層深さが異なってしまうといった問題もある。なお、このような現象は、上述の如き傾向と同様に、特に短時間加熱の場合に発生し易い。
【００２３】
なお、以上のような問題は、高周波誘導加熱装置３１についても同様な理由で発生するため、その説明を省略する。
【００２４】
本発明は、このような問題を解決するべくなされたものであって、その目的はクランクシャフトのピン部又はジャーナル部の外周面をその全周にわたり短時間で均一加熱することができ、従って焼入硬化層深さの不均一を解消し得て良好な（均一な）焼入硬化層パターンを得ることのできるクランクシャフトの高周波誘導加熱方法及び装置を提供することにある。
【００２５】
【課題を解決するための手段】
上述の目的を達成するために、本発明では、複数の高周波誘導加熱コイルをクランクシャフトのピン部又はジャーナル部の外周面上に設置する際に、前記ピン部又はジャーナル部の外周面に僅かな隙間を隔てて対向配置される前記複数の高周波誘導加熱コイルの加熱コイル部分を前記クランクシャフトのピン部又はジャーナル部の中心軸に沿う方向において互いにオフセットした位置に配置し、この状態の下で、前記クランクシャフトを前記クランクシャフトの中心軸を中心に回転させると共に前記複数の高周波誘導加熱コイルを前記クランクシャフトのピン部又はジャーナル部の外周面に追従させながら、前記複数の高周波誘導加熱コイルにそれぞれ高周波電流を供給することにより、前記ピン部又はジャーナル部の外周面を高周波誘導加熱するようにしている。
また、本発明では、前記複数の高周波誘導加熱コイルにそれぞれ同時に或いは時間差をもって高周波電流を供給するようにしている。
また、本発明では、前記複数の高周波誘導加熱コイルに供給する高周波電流の大きさをそれぞれ任意に調整可能にしている。
また、本発明では、クランクシャフトのピン部又はジャーナル部の外周面上にガイド部材を介して高周波誘導加熱コイルを載置し、前記クランクシャフトを前記クランクシャフトの中心軸を中心に回転させて前記高周波誘導加熱コイルを前記ピン部又はジャーナル部の外周面に追従させながら前記ピン部又はジャーナル部の外周面を高周波誘導加熱するようにしている。
また、本発明では、前記クランクシャフトのピン部又はジャーナル部の中心軸に沿う方向において互いに異なる外周面上の領域にそれぞれ対向配置される加熱コイル部分を有する複数の高周波誘導加熱コイルを備え、前記複数の高周波誘導加熱コイルの加熱コイル部分を前記クランクシャフトのピン部又はジャーナル部の中心軸に沿う方向において互いにオフセットした位置に配置して、前記ピン部又はジャーナル部の外周面を前記複数の高周波誘導加熱コイルの加熱コイル部分にて取り囲み、この状態の下で、前記ピン部又はジャーナル部の外周面を高周波誘導加熱するようにしている。
また、本発明では、前記クランクシャフトのピン部又はジャーナル部の外周面に対向配置される前記複数の高周波誘導加熱コイルの加熱コイル部分を互いに同一の形状に構成すると共に、前記複数の高周波誘導加熱コイルの加熱コイル部分は、前記クランクシャフトのピン部又はジャーナル部の中心線に対して直交し、かつ、前記ピン部又はジャーナル部の幅方向の２等分箇所において前記中心軸に直交する軸線に対して回転対称の位置関係を持って配置するようにしている。
【００２６】
【発明の実施の形態】
以下、本発明の一実施形態について図１〜図４並びに図５及び図９を参照して説明する。なお、図１〜図４において、図５〜図１３と同様の部分には同一の符号を付して重複する説明を省略する。
【００２７】
図１は、本発明の一実施形態に係る高周波誘導加熱装置４０を示すものであって、この高周波誘導加熱装置４０は、真鍮製又は樹脂製の一対の側板４１ａ，４１ｂ間に挟持状態で保持された第１の高周波誘導加熱コイル３０ａと、真鍮製又は樹脂製の一対の側板４２ａ，４２ｂ間に挟持状態で保持された第２の高周波誘導加熱コイル３０ｂとを備えている。
【００２８】
高周波誘導加熱装置４０に備えられる２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂは、それぞれ、図９の高周波誘導加熱コイル３０と同様に構成されたコイル体、すなわち高周波誘導加熱コイル３０と同様に構成された加熱コイル部分２９を有するコイル体であり、互いに同一の形状に構成されている。
【００２９】
また、互いに同一の形状を有する上述の２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂは、左右位置において互いに反対向きとなされて互いに対向配置されており、一対の円弧状加熱導体部３３ａ，３３ｂと、直線状加熱導体部３４と、一対の直線状加熱導体部３５ａ，３５ｂとから成る第１の高周波誘導加熱コイル３０ａの加熱コイル部分２９が、クランクシャフト１の中心軸Ｘを中心に回転駆動されるクランクシャフト１のピン部３の外周面Ｓの一方側の側面半分部分に対向配置されるように構成されると共に、第２の高周波誘導加熱コイル３０ｂの加熱コイル部分２９が、クランクシャフト１の中心軸Ｘを中心に回転駆動されるクランクシャフト１のピン部３の外周面Ｓの他方側の側面半分部分に対向配置されるように構成されている。かくして、第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂの各々の加熱コイル部分２９の円弧状加熱導体部３３ａ，３３ｂが、ピン部３の中心軸Ｙに沿う方向において互いにオフセットした配置関係をもって互いに対向するような状態で、ピン部３の直径に対応する直径の円周上に沿って配置されるようになっている。
【００３０】
また、図１に示すように、第１の高周波誘導加熱コイル３０ａの給電リード部３２ａ，３２ｂは、高周波電流供給用のトランス（図示せず）を介して第１の高周波電源１２ａに接続されると共に、第２の高周波誘導加熱コイル３０ｂの給電リード部３２ａ，３２ｂは、高周波電流供給用のトランス（図示せず）を介して第２の高周波電源１２ｂに接続されている。かくして、第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂには、上述の第１及び第２の高周波電源１２ａ，１２から図外のトランスをそれぞれ介して所定の高周波電流が供給されるように構成されている。
【００３１】
さらに、第１の高周波誘導加熱コイル３０ａが取付けられている一対の側板４１ａ，４１ｂ間には、第１の高周波誘導加熱コイル３０ａに対応する箇所に一対のガイド部材４３ａ，４３ｂが取付けられており、第２の高周波誘導加熱コイル３０ｂが取付けられている一対の側板４２ａ，４２ｂ間には、前記第２の高周波誘導加熱コイル３０ｂに対応する箇所に一対のガイド部材４４ａ，４４ｂが取付けられている。かくして、前記２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂは、これらのガイド部材４３ａ，４３ｂ及び４４ａ，４４ｂを介して、加熱対象であるピン部３の中心軸Ｙを挟む左右２方向からこのピン部３の外周面Ｓに対して僅かな隙間を隔てて対向配置され、これによりピン部３の外周面Ｓのほぼ全周が第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂの加熱コイル部分２９にて取り囲まれた状態となるように構成されている。
【００３２】
図２（ａ）及び（ｂ）は、上述の高周波誘導加熱装置４０の図１中のＡ−Ａ線断面の例を示すものであって、図２（ａ）は、平焼入用高周波誘導加熱装置としての高周波誘導加熱コイル３０ａ，３０ｂを備えた高周波誘導加熱蓑置４０のＡ−Ａ線断面図であり、図２（ｂ）は、フィレットＲ焼入用高周波誘導加熱装置としての高周波誘導加熱コイル３０ａ，３０ｂを備えた高周波誘導加熱装置４０のＡ−Ａ線断面図である。
【００３３】
図２（ａ），（ｂ）中において、加熱対象であるピン３に対する２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂの位置関係に関して共通している点は、２台の高周波誘導加熱コイル３０ａ，３０ｂの加熱コイル部分２９が、ピン部３の中心軸Ｙと直交しかつピン部３の幅方向を２等分する箇所（ピン部３の幅方向の２等分箇所）においてピン部３の中心軸Ｙに直交する軸線Ｚを中心とした回転対称な位置関係をもって配置され、第１の高周波誘導加熱コイル３０ａの円弧状加熱導体部３３ａ，３３ｂと第２の高周波誘導加熱コイル３０ｂの円弧状加熱導体部３３ａ，３３ｂとがピン部３の中心軸Ｙに沿う方向において全て異なる位置に配置されるように設定されていることである。更に詳しく述べると、第１の高周波誘導加熱コイル３０ａの構成要素である一対の円弧状加熱導体部３３ａ，３３ｂが挟む領域（一対の円弧状加熱導体部３３ａ，３３ｂ間の領域）、すなわち第１の高周波誘導加熱コイル３０ａのみでは誘導加熱されにくい領域β_１には、もう一方の第２の高周波誘導加熱コイル３０ｂの円弧状加熱導体部３３ａが対向するように配置されると共に、もう一方の第２の高周波誘導加熱コイル３０ｂの構成要素である一対の円弧状加熱導体部３３ａ，３３ｂが挟む領域（一対の円弧状加熱導体部３３ａ，３３ｂ間の領域）、すなわち第２の高周波誘導加熱コイル３０ｂの加熱コイル部分２９のみでは誘導加熱されにくい領域β_２には、第１の高周波誘導加熱コイル３０ａの円弧状加熱導体部３３ｂが対向するように２台の第１及び第２の高周波誘導加熱コイルが対向配置される構成されている。そのため、ピン部３の外周面Ｓは、中心軸Ｙに沿う方向（ピン幅方向）のほぼ全域が第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂのそれぞれの円弧状加熱導体部３３ａ，３３ｂと対向する状態になる。なお、図２中のα_１〜α_４は、各加熱導体部３３ａ，３３ｂによる加熱領域である）。
【００３４】
このような状態で、中心軸Ｘを中心にクランクシャフトを回転駆動させて、図外の追従機構により前記中心軸Ｘを中心として公転運動するピン部３に第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂを追従させながら、これらの第２及び第２の高周波誘導加熱コイル３０ａ，３０ｂに第１及び第２の高周波電源１２ａ，１２ｂからそれぞれ高周波電流を供給することにより、加熱対象であるピン部３の外周面Ｓに対して既述のような配置関係をもって配置された２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂによってピン部３の外周面Ｓで各々の誘導加熱されにくい領域β_１、β_２を互いに補完するように均一に誘導加熱することが可能となる。
【００３５】
なお、上述した誘導加熱の態様は、クランクシャフト１のジャーナル部２の誘導加熱においても同様である。
【００３６】
また、図２（ｃ）は、上述の高周波誘導加熱装置４０の図１中のＡ−Ａ線断面図の他の例を示すものであり、クランクシャフト１のジャーナル部２ａの外周面Ｈ，片側のＲ部Ｍ，及びスラスト部Ｎに連続する焼入硬化層を形成させる片Ｒ焼入用高周波誘導加熱装置としての高周波誘導加熱コイル３０ａ，３０ｂを備えた高周波誘導加熱装置４０のＡ−Ａ線断面図であり、特に片側にカウンターウエイト部が隣接しないジャーナル部２ａ（図５参照）に高周波焼入を施行する場合において有効である。
【００３７】
ジャーナル部２ａにはその一方側（図５では右側）にカウンターウエイト部４ａが隣接しているが、このカウンターウエイト４ａ側のＲ部Ｍと外周面Ｈに連続した焼入硬化層を形成する場合には、図１に示すように２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂをジャーナル部２ａの中心軸Ｘを挟む左右２方向から対向配置した状態の下で高周波誘導加熱が行なわれる。すなわち、図２（ｃ）に示すように、第１の高周波誘導加熱コイル３０ａの円弧状加熱導体部３３ａがジャーナル部２ａの外周面Ｈに対して僅かな隙間を隔てて対向配置され、第１の高周波誘導加熱コイル３０ａの円弧状加熱導体部３３ｂがジャーナル部２のＲ部Ｍの近傍に配置される。そして、第２の高周波誘導加熱コイル３０ｂの一対の円弧状加熱導体部３３ａ，３３ｂは、図２（ｃ）に示すように、第１の高周波誘導加熱コイル３０ａの円弧状加熱導体部３３ａの加熱領域を挟み込むように配置され、第２の高周波誘導加熱コイル３０ｂの円弧状加熱導体部３３ｂが第１の高周波誘導加熱コイル３０ａの円弧状加熱導体部３３ａ，３３ｂ間の領域に対応する位置に配置される。
【００３８】
なお、第１の高周波誘導加熱コイル３０ａの円弧状加熱導体部３３ａ，３３ｂの断面形状は、フィレットＲ焼入用高周波誘導加熱装置を構成する高周波誘導加熱コイルと類似形状をとり、第２の高周波誘導加熱コイル３０ｂの円弧状加熱導体部３３ａ，３３ｂの断面形状は、平焼入用高周波誘導加熱装置を構成する半開放鞍型加熱コイルと類似形状である（図２（ｃ）参照）。
【００３９】
上述したように、ジャーナル部２ａの高周波誘導加熱に際しても、図２（ａ），（ｂ）に示すピン部３の高周波誘導加熱の場合と同様に、２台の第１及び第２の高周波誘導加熱コイル３０ａ及び３０ｂの円弧状加熱導体部３３ａ，３３ｂがジャーナル部２の中心軸Ｘに沿う方向において全て異なる位置に配置するようにしている。更に詳しくは、第１の高周波誘導加熱コイル３０ａの構成要素である一対の円弧状加熱導体部３３ａ，３３ｂが挟む領域、すなわち第１の高周波誘導加熱コイル３０ａのみでは誘導加熱されにくい領域γ_１，γ_２に第２の高周波誘導加熱コイル３０ｂの円弧状加熱導体部３３ａ，３３ｂをそれぞれ対向配置すると共に、第２の高周波誘導加熱コイル３０ｂの構成要素である一対の円弧状加熱導体部３３ａ、３３ｂが挟む、誘導加熱されにくい領域γ_３に第１の高周波誘導加熱コイル３０ａの円弧状加熱導体部３３ａを対向配置するように、２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂを配置するようにしている。これにより、ジャーナル部２ａの外周面Ｈは、中心軸Ｘに沿う方向においてほぼ全域が第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂのそれぞれの円弧状加熱導体部３３ａ，３３ｂに対向配置された状態になるように構成されている。
【００４０】
従って、このような状態で、中心軸Ｘを中心として回転駆動されたクランクシャフト１の回転運動に伴って公転運動を行うピン部に高周波誘導加熱装置４０を追従させて高周波誘導加熱を行なうと、既述の如く平焼入及びフィレットＲ焼入の場合と同様に配置された２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂによってジャーナル部２ａの外周面Ｈにおいてそれぞれ誘導加熱されにくい領域γ_１，γ_２，及びγ_３を互いに補完するように均一に誘導加熱することが可能となる。
【００４１】
さらに、上述した片側のＲ部Ｍとスラスト部Ｎに硬化層を形成させる片Ｒ焼入用高周波誘導加熱装置としての２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂを備えた高周波誘導加熱装置４０によれば、これらの高周波誘導加熱コイル３０ａ，３０ｂに高周波電流を供給するに際し、同時に或いは時間差をもって高周波電流を供給可能なようにしているため、ジャーナル部２ａの外周面Ｈ及びＲ部Ｍ形成される焼入硬化層深さを調整することが可能である。
【００４２】
前述したようにジャーナル部２ａには片側にカウンターウエイト部４ａがあ
り、もう一方の側にはカウンターウエイト部がないため、ヒートマス（熱質量）に極端な差があり、ヒートマスの大きいカウンターウエイト４ａ側のＲ部Ｍにおける焼入硬化層深さは、熱伝導により熱が奪われるため焼入硬化層深さが浅くなり易く、反対側（カウンターウエイトが無い側）はヒートマスが小さいので加熱され易く、焼入硬化層深さが深くなる傾向がみられる。
【００４３】
そこで、カウンターウエイト部４ａ側のＲ部Ｍの焼入硬化層深さを深くし、反対側の焼入硬化層深さを浅くするためには、まず、第１の高周波誘導加熱コイル３０ａに第１の高周波電源１２ａより高周波電流を供給し、次いで所要時間経過後に第２の高周波誘導加熱コイル３０ｂに第２の高周波電源１２ｂより高周波電流を供給することにより、Ｒ部Ｍの近傍部分が先に昇温を開始してこれに続いて外周面Ｈが昇温するため、Ｒ部Ｍには深い焼入硬化層を、そして外周面Ｈは浅い焼入硬化層をそれぞれ得ることができる。
【００４４】
また、片側のＲ部Ｍとスラスト部Ｎに硬化層を形成させる片Ｒ焼入用高周波誘導加熱装置としての２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂを備えた高周波誘導加熱装置４０は、これらの高周波誘導加熱コイル３０ａ、３０ｂに供給する高周波電流の大きさは各々任意に選択調整可能であるため、ジャーナル部２ａの外周面とＲ部の硬化層深さを調整することが可能である。
【００４５】
例えば、ジャーナル部２ａのＲ部Ｍには深い焼入硬化層を形成すると共に外周面Ｈには浅い焼入硬化層を形成する場合には、第１の高周波誘導加熱コイル３０ａに供給する高周波電流を、第２の高周波誘導加熱コイル３０ｂに供給する高周波電流の大きさによりも相対的に小さくすればよい。この場合には、Ｒ部Ｍの近傍箇所に流れる誘導電流の値は外周面Ｈに流れる誘導電流の値よりも大きくなるため、Ｒ部Ｍには外周面Ｈよりも深い焼入硬化層を形成することができる。
【００４６】
図３は本発明の別の実施形態に係る高周波誘導加熱装置５０を示すものであって、この高周波誘導加熱装置５０は、真鍮製又は樹脂製の一対の側板４１ａ，４１ｂ間に挟持状態で保持された第１の高周波誘導加熱コイル１１ａと、真鍮製又は樹脂製の一対の側板４２ａ，４２ｂ間に挟持状態で保持された第２の高周波誘導加熱コイル１１ｂとを備えている。
【００４７】
高周波誘導加熱装置５０に備えられる２台の第１及び第２の高周波誘導加熱コイル１１ａ，１１ｂは、それぞれ、図７の高周波誘導加熱コイル１１と同様に構成されたコイル体、すなわち高周波誘導加熱コイル１１と同様に構成された第１及び第２の加熱コイル部分１４ａ，１４ｂを有するコイル体であり、互いに同一の形状に構成されている。
【００４８】
また、互いに同一の形状を有する上述の２台の第１及び第２の高周波誘導加熱コイル１１ａ，１１ｂは、左右位置において互いに反対向きとなされて互いに対向配置されており、第１の高周波誘導加熱コイル１１ａの加熱コイル部分１４ａ，１４ｂが、クランクシャフト１の中心軸Ｘを中心に回転駆動されるクランクシャフト１のピン部３の外周面Ｓの一方側の側面半分部分に対向配置されるように構成されると共に、第２の高周波誘導加熱コイル１１ｂの加熱コイル部分１４ａ，１４ｂが、クランクシャフト１の中心軸Ｘを中心に回転駆動されるクランクシャフト１のピン部３の外周面Ｓの他方側の側面半分部分に対向配置されるように構成されている。かくして、第１及び第２の高周波誘導加熱コイル１１ａ，１１ｂの各々の加熱コイル部分１４ａ，１４ｂが、ピン部３の中心軸Ｙに沿う方向において互いにオフセットした配置関係をもって互いに対向した状態で、ピン部３の直径に対応する直径の円周上に沿って配置されている。
【００４９】
また、図７に示すように、第１の高周波誘導加熱コイル１１ａの給電リード部１６ａ，１６ｂは、高周波電流供給用のトランス（図示せず）を介して第１の高周波電源１２ａに接続されると共に、第２の高周波誘導加熱コイル１１ｂの給電リード部１６ａ，１６ｂは、高周波電流供給用のトランス（図示せず）を介して第２の高周波電源１２ｂに接続されている。かくして、第１及び第２の高周波誘導加熱コイル１１ａ，１１ｂには、上述の第１及び第２の高周波電源１２ａ，１２から図外のトランスをそれぞれ介して所定の高周波電流が供給されるように構成されている。
【００５０】
さらに、本実施形態の高周波誘導加熱装置５０にあっては、第１の高周波誘導加熱コイル１１ａが取付けられる一対の側板４１ａ，４１ｂには例えば３つのセラミック製又は超硬合金製のガイド部材５１ａ，５１ｂ，５１ｃが固定されており、第２の高周波誘導加熱コイル１１ｂが取付けられる一対の側板４２ａ，４２ｂには第２の高周波誘導加熱コイル１１ｂの加熱コイル部分１４ａ，１４ｂ間の１箇所にのみガイド部材５１ｄが固定されている。
【００５１】
図４（ａ）は、図３におけるＢ−Ｂ線断面を示すものであり、第１の高周波誘導加熱コイル１１ａの加熱コイル部分１４ａ，１４ｂの一対の円弧状加熱導体部１７ａ，１８ａと１７ｂ，１８ｂとがピン部３のＲ部Ｍの近傍にそれぞれ配置され、これらの円弧状加熱導体部１７ａ，１７ｂが同一円周上に配置されると共に円弧状加熱導体部１８ａ，１８ｂが同一円周上に配置される。
【００５２】
図４（ｂ）は、図３におけるＣ−Ｃ線断面を示すものであり、第２の高周波誘導加熱コイル１１ｂの第１の加熱コイル部分１４ａの一対の円弧状加熱導体部１７ａ，１８ａと、第２の加熱コイル部分１４ｂの一対の円弧状加熱導体部１７ｂ，１８ｂとは、ピン部３の外周面Ｓ上にそれぞれの加熱領域が重複しないように互いにオフセットされた位置に配置される。そして、第２の高周波誘導加熱コイル１１ｂによる加熱領域は、第１の高周波誘導加熱コイル１１ａの円弧状加熱導体部１７ａ，１７ｂと１８ａ，１８ｂとによる加熱領域の間に位置するように配置される。
【００５３】
従って、ピン部３の外周面Ｓ及びＲ部Ｍの近傍領域の全てが前記２台の第１及び第２の高周波誘導加熱コイル１１ａ，１１ｂの円弧状加熱導体部１７ａ，１７ｂ，１８ａ，１８ｂに対向するため、外周面Ｓの全周面にわたって均一に誘導加熱を行うことができる。
【００５４】
また、前述した片Ｒ焼入の場合と同様に、２台の高周波誘導加熱コイル１１ａ，１１ｂに高周波電流を時間差を以て供給することにより、或いはそれぞれに供給する高周波電流の大きさを各々適宜選択することにより、Ｒ部Ｍ及び外周面Ｓの昇温速度を調整することにより硬化層全体の深さを任意に調整可能である。
【００５５】
以上、本発明の一実施形態について述べたが、本発明はこの実施形態に限定されるものではなく、本発明の技術的思想に基づいて各種の変形及び変更が可能である。例えば、本発明の別の実施形態における高周波誘導加熱装置５０の第１及び第２の高周波誘導加熱コイル１１ａ，１１ｂの形状は、２台とも従来の高周波誘導加熱装置の高周波誘導加熱コイル１１と同等の構成のものとしたが、一方を高周波誘導加熱コイル３０と同等形状のものとしても良く、さらに、既述の実施形態では両方のＲ部Ｍの近傍に配置された第１の高周波誘導加熱コイル１１ａと外周面Ｓに対向配置された第２の高周波誘導加熱コイル１１ｂに供給する高周波電流の大きさを調節することにより焼入硬化層各部の深さを調整するようにしているが、この２台の第１及び第２の高周波誘導加熱コイル１１ａ，１１ｂに異なる周波数の高周波電流を供給することにより焼入硬化層各部の深さを調整するようにしてもよい。また、既述の実施形態では、全て、２台の第１及び第２の高周波誘導加熱コイル３０ａ，３０ｂ、或いは、１１ａ，１１ｂとしたが、３台以上の高周波誘導加熱コイルをピン部３或いはジャーナル部２に対応配置して高周波誘導加熱を行なうことも可能である。また、既述の実施形態では、高周波誘導加熱による高周波焼入について述べたが、高周波焼戻にも適用可能である。
【００５６】
【発明の効果】
請求項１に記載の本発明は、クランクシャフトのピン部又はジャーナル部の外周面に僅かな隙間を隔てて対向配置される複数の高周波誘導加熱コイルの加熱コイル部分をクランクシャフトのピン部又はジャーナル部の中心軸に沿う方向において互いにオフセットした位置に配置して高周波誘導加熱するようにしたものであるから、加熱対象であるピン部又はジャーナル部の外周面の幅方向（ピン部又はジャーナル部の中心軸に沿う方向）において前記外周面のほぼ全域に複数の高周波誘導加熱コイルの加熱コイル部分を対向配置することが可能となり、ピン部或いはジャーナル部の外周面を全周面にわたり熱伝導に依存することなく均一に高周波誘導加熱することができる。従って、熱伝導のために加熱時間を延長することなく、短時間で深さのバラツキの少ない良好な焼入硬化層を形成させることが可能であり、クランクシャフトの熱処理時間を短縮し得て生産性を向上させることができる。
【００５７】
また、請求項２に記載の本発明は、複数の高周波誘導加熱コイルにそれぞれ同時に或いは時間差をもって高周波電流を供給するようにしたものであるから、各高周波誘導加熱コイルの高周波電流を供給するタイミングを変化させることにより、焼入硬化層の各部の硬化層深さを任意に調整することが可能であり、高周波誘導加熱コイルの調整、交換を伴うことなく、多種多様な焼入仕様に対応することができる。
【００５８】
また、請求項３に記載の本発明は、前記複数の高周波誘導加熱コイルに供給する高周波電流の大きさをそれぞれ任意に調整可能にしたものであるから、各高周波誘導加熱コイルヘ供給する高周波電流の大きさを変化させることにより、焼入硬化層の各部の硬化層深さを任意に調整することができるため、高周波誘導加熱ニイルの調整、交換を伴うことなく、多種多様な焼入仕様に対応することができる。
【００５９】
また、請求項４に記載の本発明は、クランクシャフトのピン部又はジャーナル部の中心軸に沿う方向において互いに異なる外周面上の領域にそれぞれ対向配置される加熱コイル部分を有する複数の高周波誘導加熱コイルを備え、複数の高周波誘導加熱コイルの加熱コイル部分をクランクシャフトのピン部又はジャーナル部の中心軸に沿う方向において互いにオフセットした位置に配置して高周波誘導加熱するようにしたものであるから、クランクシャフトのピン部或いはジャーナル部の全周面にわたり熱伝導に依存することなく均一に加熱することができる。そのため、熱伝導のために加熱時間を延長することなく、短時間で深さのバラツキの少ない良好な焼入硬化層を形成させることが可能であり、クランクシャフトの熱処理時間を短縮し得て生産性を向上させることができる。
【００６０】
また、請求項５に記載の本発明は、クランクシャフトのピン部又はジャーナル部の外周面に対向配置される複数の高周波誘導加熱コイルの加熱コイル部分を互いに同一の形状に構成すると共に、複数の高周波誘導加熱コイルの加熱コイル部分は、クランクシャフトのピン部又はジャーナル部の中心線に対して直交し、かつ、ピン部又はジャーナル部の幅方向の２等分箇所において前記中心軸に直交する軸線に対して回転対称の位置関係を持って配置するようにしたものであるから、一方の高周波誘導加熱コイルの加熱コイル部分にて加熱しにくい領域を他方の高周波誘導加熱コイルの加熱コイル部分により補完的に高周波誘導加熱することができ、均一な加熱処理を行なうことができる。
【図面の簡単な説明】
【図１】本発明に係るクランクシャフトの高周波誘導加熱方法を実施するために用いられる高周波誘導加熱装置の側面図である。
【図２】図２（ａ）及び（ｂ）は図１におけるＡ−Ａ線拡大断面図、図２（ｃ）はジャーナル部を高周波誘導加熱する場合を示す図２（ａ），（ｂ）と同様の断面図である。
【図３】本発明に係るクランクシャフトの高周波誘導加熱方法を実施するための別の実施形態の高周波焼入装置の側面図である。
【図４】図４（ａ）は図３におけるＢ−Ｂ線拡大断面図、図４（ｂ）は図３におけるＣ−Ｃ線拡大断面図である。
【図５】４気筒エンジン用クランクシャフトの斜視図である。
【図６】従来のクランクシャフトの高周波誘導加熱装置の側面図である。。
【図７】図６の高周波誘導加熱装置の構成要素である高周波誘導加熱コイルの概斜視図である。
【図８】従来の別のクランクシャフトの高周波誘導加熱装置の側面図である。
【図９】図８の高周波誘導加熱装置の構成要素である別の高周波誘導加熱コイルの斜視図である。
【図１０】ピン部及びジャーナル部の外周面に形成される好ましい焼入硬化層を示す断面図である。
【図１１】図１１（ａ）は従来のクランクシャフトの高周波誘導加熱装置を用いてピン部の外周面を平焼入のために高周波誘導加熱する場合の高周波誘導加熱コイルの配置関係を示す図６におけるＤ−Ｄ線拡大断面図、図１１（ｂ）はピン部の外周面に形成される焼入硬化層パターンを示す断面図である。
【図１２】図１２（ａ）は従来のクランクシャフトの高周波誘導加熱装置を用いてピン部の外周面をフィレットＲ焼入のために高周波誘導加熱する場合の高周波誘導加熱コイルの配置関係を示す断面図、図１２（ｂ）はピン部の外周面に形成される焼入硬化層パターンを示す断面図である。
【図１３】図１３（ａ）は従来のクランクシャフトの高周波誘導加熱装置を用いてピン部の外周面を片Ｒ焼入のために高周波誘導加熱する場合の高周波誘導加熱コイルの配置関係を示す断面図、図１３（ｂ）はピン部の外周面に形成される焼入硬化層パターンを示す断面図である。
【符号の説明】
１４気筒エンジン用クランクシャフト
２（２ａ〜２ｅ）ジャーナル部
３（３ａ〜３ｄ）ピン部
１１ａ第１の高周波誘導加熱コイル
１１ｂ第２の高周波誘導加熱コイル
１２ａ第１の高周波電源
１２ｂ第２の高周波電源
１４ａ第１の加熱コイル部分
１４ｂ第２の加熱コイル部分
１７ａ，１７ｂ，１８ａ，１８ｂ円弧状加熱導体部
２９加熱コイル部分
３０ａ第１の高周波誘導加熱コイル
３０ｂ第２の高周波誘導加熱コイル
４３ａ，４３ｂ，４４ａ，４４ｂガイド部材
５１ａ〜５１ｄガイド部材
Ｈジャーナル部の外周面
Ｓピン部の外周面
Ｘクランクシャフトの中心軸
Ｙピン部の中心軸[0001]
BACKGROUND OF THE INVENTION
The present invention provides high-frequency induction heating that performs high-frequency induction heating on the outer peripheral surface (including the cylindrical outer peripheral surface and curved corners on both sides thereof) of a crankshaft pin or journal for quenching or tempering. It relates to a method and a device.
[0002]
[Prior art]
FIG. 5 shows a crankshaft 1 for a four-cylinder engine. The crankshaft 1 has journal portions 2a, 2b, 2c, 2d, centered on a central axis X (same as the axis of the journal portion). 2e, pin portions 3a, 3b, 3c, 3d that are eccentric with respect to the central axis X, counterweight portions 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, and flange portion 5 It is formed integrally by forging. In the case of a crankshaft for a multiple cylinder engine, a plurality of pin portions 3 are provided. In the case of the crankshaft 1 for a four cylinder engine shown in FIG. 5, four pin portions 3a to 3d are provided. And these pin parts 3a-3d are each arrange | positioned between the counterweight parts 4 which adjoin each other in the location spaced apart by predetermined intervals along the axial direction of the central axis X. Further, the pin portions 3a to 3d that are adjacent to each other in the axial direction of the central axis X are disposed at angular positions that differ by a predetermined phase angle around the central axis X according to the type of the engine. In the case of the crankshaft 1 for a four-cylinder engine shown in FIG. 5, the pin portions 3a, 3d (center axis Y ₁ Are disposed at locations having the same phase angle, and pin portions 3b and 3c (center axis Y) between these pin portions 3a and 3d. ₂ The pin portions 3a, 3d on the left and right ends and the pin portions 3b, 3c at the intermediate positions are disposed at a phase angle of 180 degrees with respect to each other.
[0003]
In the crankshaft 1 of this type, conventionally, the outer peripheral surfaces of the journal portions 2a to 2e and the pin portions 3a to 3d of the crankshaft 1 are hardened by high-frequency induction heating, respectively, thereby improving wear resistance and fatigue. The strength is improved. Here, the case where the pin portions 3a to 3d of the crankshaft 1 (hereinafter collectively referred to as the pin portion 3) are subjected to high-frequency induction heating will be described as an example.
[0004]
FIG. 6 shows a high-frequency induction heating device 8 conventionally used for high-frequency induction heating of the outer peripheral surface S of the pin portion 3 during the quenching process. As shown in FIG. 6, the induction hardening device 8 is held in a state of being sandwiched between a pair of side plates 10 a and 10 b made of brass or resin, and is driven to rotate around the central axis X of the crankshaft 1. A semi-open saddle type high frequency induction heating coil (semi-open saddle type coil) 11 disposed opposite to the upper half portion of the outer peripheral surface S of the pin portion 3 to be applied, and a high frequency for supplying a high frequency current to the high frequency induction heating coil 11 A power source 12 and, for example, three ceramic or cemented carbide guide members (chip members) 13a, 13b, and 13c fixed to the pair of side plates 10a and 10 are provided.
[0005]
As shown in FIGS. 6 and 7, the above-described high-frequency induction heating coil 11 includes a pair of left and right first and second heating coil portions 14a and 14b constituting a coil head, and a pair of these heating coil portions 14a. , 14b are connected to each other, and feeding lead portions 16a, 16b connected to the pair of connecting conductor portions 15a, 15b, respectively. The above-described feeding lead portions 16a, 16b are high frequency. Connected to a power supply 12. An example of a coil body having such a structure is disclosed in Japanese Patent Application Laid-Open No. 2001-181739. Here, the first heating coil portion 14a of the high frequency induction heating coil 11 will be described in detail. As shown in FIG. 7, the first heating coil portion 14a is a pair of arc-shaped heating conductor portions 17a parallel to each other. , 18a, one end of the arc-shaped heating conductor portion 17a and one end of the arc-shaped heating conductor portion 18a, and the other end of the arc-shaped heating conductor portions 17a, 18a and the connecting conductor portion 15a. , 15c and linear heating conductors 20a, 21a respectively connecting one end of each of them, and having a generally rectangular shape that is curved as a whole. The second heating coil portion 14b is also configured in the same manner as the first heating coil portion 14a described above, and the pair of heating coil portions 14a and 14b are arranged correspondingly with a symmetrical arrangement relationship. In FIG. 7, a pair of arc-shaped heating conductor portions 17 b and 18 b, a linear heating conductor portion 19 b, connection conductor portions 15 a and 15 c, and a feed lead portion 16 b of the second heating coil portion 14 b are illustrated. However, the linear heating conductor portions 20b and 21b corresponding to the linear heating conductor portions 20a and 21a described above are not illustrated because they are in a hidden position.
[0006]
The power feed leads 16a and 16b are connected to a transformer (not shown) for supplying high-frequency current, and a predetermined high-frequency current is supplied from the high-frequency power source 20 to the transformer.
[0007]
When the high-frequency induction heating device 8 performs high-frequency induction heating of the outer peripheral surface S of the pin portion 3 of the crankshaft 1 for quenching or tempering, the high-frequency induction heating device 8 is moved by a lifting mechanism (not shown). It is moved down from a predetermined standby position, placed on the outer peripheral surface S of the pin portion 3 via the guide member 13b, and brought into contact with the outer peripheral surface S of the pin portion 3 by high frequency induction heating. The coil 11 is disposed to face the upper half portion of the outer peripheral surface S of the pin portion 3 with a slight gap. Under this state, the crankshaft 1 is rotationally driven around the central axis X of the crankshaft 1 by a rotational drive mechanism (not shown). Along with this, the pin portion 3 revolves around the central axis X. At this time, the high-frequency induction heating device 8 follows the pin portion 3 by a tracking mechanism (not shown), and the first and second heating coil portions 14a and 14b of the high-frequency induction heating coil 11 The state of being always opposed to the upper half portion of the outer peripheral surface S is maintained.
[0008]
Under such a state, the first and second heating coil portions of the high-frequency induction heating coil 11 are sequentially passed from the high-frequency power source 12 through a transformer (not shown), power supply lead portions 16a and 16b, and connecting conductor portions 15a and 15b. A high frequency current is supplied to 14a and 14b, and the outer peripheral surface S of the pin part 3 is induction-heated by this. Next, when the outer peripheral surface S of the pin portion 3 is induction-heated to a required quenching temperature, the supply of the high-frequency current from the high-frequency power source 12 to the high-frequency induction heating coil 11 is interrupted, and the outer peripheral surface S of the pin portion 3 is stopped. The quenching cooling water is jetted by quenching cooling water jetting means (not shown). Thereby, the outer peripheral surface S of the pin part 3 is rapidly cooled, and a hardening hardening layer is formed on the surface.
[0009]
FIG. 8 shows a conventional high-frequency induction heating apparatus 31 including a semi-open saddle type high-frequency induction heating coil (half-open saddle type coil) 30 having another shape. As shown in FIG. 8, the high-frequency induction heating device 31 is held in a state of being sandwiched between a pair of side plates 10 a and 10 b made of brass or resin, and is driven to rotate around the central axis X of the crankshaft 1. A high frequency induction heating coil 30 having one heating coil portion 29 disposed opposite to the upper half portion of the outer peripheral surface S of the pin portion 3 (pin portions 3a to 3d). The other configuration is the same as that of the high-frequency induction heating device 8 of FIG.
[0010]
As shown in FIGS. 8 and 9, the high-frequency induction heating coil 30 includes one heating coil portion 29 constituting a coil head) and a pair of power supply lead portions 32 a connected to the heating coil portion 29. 32b, and the power feed leads 32a and 32b described above are connected to the high frequency power supply 12. An example of a similar coil body having such a structure is disclosed in JP-A-3-183724. Here, the configuration of the heating coil portion 29 of the high frequency induction heating coil 30 will be described in detail. As shown in FIG. 9, the heating coil portion 29 includes a pair of arc-shaped heating conductor portions 33a and 33b parallel to each other, A linear heating conductor 34 that connects one end of the arc-shaped heating conductor 33a and one end of the arc-shaped heating conductor 33b, the other end of the arcuate conductors 33a and 33b, and one end of the power feed leads 32a and 32b Are respectively formed of linear heating conductor portions 35a and 35b.
[0011]
The power feed leads 32 a and 32 b are connected to a high frequency power supply 12 via a high frequency current supply transformer (not shown), and a predetermined high frequency current is heated from the high frequency power supply 12 to the high frequency induction heating coil 30. The coil portion 29 is configured to be supplied.
[0012]
The above-described high-frequency induction heating device 31 is particularly effective for high-frequency induction heating of a small crankshaft in which the diameter of the pin portion 3 or the journal portion 2 is small. The reason for this is as follows. That is, in the high frequency induction heating device 8 of FIG. 6, the head of the high frequency induction heating coil 11 is divided into two heating coil portions 14a and 14b, and the arc-shaped heating conductor portions 17a and 17b are circumferentially arranged. And the arc-shaped heating conductor portions 18a and 18b are divided into two in the circumferential direction, so that when the diameter of the pin portions 3a to 3d or the journal portions 2a to 2e is small, Although the arc lengths of the arc-shaped heating conductor portions 15a and 15b and 16a and 16b are relatively short and the heating efficiency is deteriorated, the heating coil portion 29 of the high-frequency induction heating coil 30 is used in the high-frequency induction heating device 31 of FIG. Since the arc-shaped heating conductor portions 33a and 33b are not divided into two, the arc-shaped heating conductor portions 33a and 33b facing the outer circumferential surface S of the pin portion 3 (or the outer circumferential surface H of the journal portion 2) There is for relatively longer than the above case, the heating efficiency is improved due to this.
[0013]
When the high-frequency induction heating device 31 of FIG. 8 performs high-frequency induction heating of the outer peripheral surface S of the pin portion 3 of the crankshaft 1 for quenching, for example, the high-frequency induction heating device 31 is predetermined by an elevating mechanism (not shown). The high-frequency induction heating coil is moved downward from the standby position and placed on the outer peripheral surface S of the pin portion 3 via the guide members 13a to 13c, and the guide member 15b is brought into contact with the outer peripheral surface S of the pin portion 3. 30 is arranged opposite to the upper half portion of the outer peripheral surface S of the pin portion 3 with a slight gap. Under this state, the crankshaft 1 is rotationally driven around the central axis X of the crankshaft 1 by a rotational drive mechanism (not shown). Along with this, the pin portion 3 revolves around the central axis X. At this time, the high frequency induction heating device 31 follows the pin portion 3 by a tracking mechanism (not shown), and the heating coil portion 29 of the high frequency induction heating coil 30 always faces the upper half portion of the outer peripheral surface S of the pin portion 3. Keep it in place.
[0014]
Under such a state, a high frequency current is supplied from the high frequency power source 12 to the heating coil portion 29 of the high frequency induction heating coil 30 through the transformer and the feed lead portions 32a and 32b (not shown) in sequence, thereby the pin portion 3 The outer peripheral surface S is induction-heated. Next, when the outer peripheral surface S of the pin portion 3 is induction-heated to a required quenching temperature, the supply of the high-frequency current from the high-frequency power source 12 to the high-frequency induction heating coil 30 is interrupted, and the outer peripheral surface S of the pin portion 3 is stopped. The quenching cooling water is jetted by quenching cooling water jetting means (not shown). Thereby, the outer peripheral surface S of the pin part 3 is rapidly cooled, and a hardening hardening layer is formed on the surface.
[0015]
FIGS. 10A to 10C are typical examples of the cross-sectional shape of the high-frequency induction heating coil 11 or 30, and are desirably obtained on the outer peripheral surface S of the pin portion 3 by the quenching process as described above (ideal N) Hardened layer pattern P ₁ , P ₂ , P ₃ Respectively. As shown in FIG. 6A, the hardened and hardened layer pattern P is formed only on the outer peripheral surface (cylindrical outer peripheral surface) S of the pin portion 3. ₁ The quenching forming pattern is referred to as flat quenching, and as shown in FIG. 6 (b), the hardened hardened layer pattern P connected from the outer peripheral surface S of the pin portion 3 to the R portions (arc-shaped corners) M on both sides thereof. ₂ A quench hardening layer pattern which is called fillet R quenching and is connected to the R portion M and the thrust portion (planar portion) N on one side from the outer peripheral surface S of the pin portion 3 as shown in FIG. P ₃ The quenching that forms is usually referred to as piece R quenching.
[0016]
[Patent Document 1]
JP 2001-181739 A
[Patent Document 2]
Japanese Patent Laid-Open No. 3-183724
[0017]
[Problems to be solved by the invention]
However, the hardened and hardened layer P formed by the conventional high frequency induction heating device 8 (or 31). ₁ , P ₂ , P ₃ As shown in FIGS. 11 to 13, the hardened hardening layer depth tends to be non-uniform. The reason for this will be described below.
[0018]
First, FIG. 11A is a view showing a cross section (cross section taken along line DD in FIG. 6) of a flat quenching high frequency induction heating coil 11 of a conventional high frequency induction heating apparatus 8. FIG. As shown in FIG. 11A, the arc-shaped heating conductor of the arc-shaped heating conductor portions 17a, 18a, 17b, and 18b constituting the first and second heating coil portions 14a and 14b of the high-frequency induction heating coil 8 is used. The portions 17a and 17b are arranged at the same position in the direction along the center axis X of the crankshaft 1 and are opposed to the outer peripheral surface S of the pin portion 3, and the arc-shaped heating conductor portions 18a and 18b are Since they are arranged at the same position in the direction along the axis X and are opposed to the outer peripheral surface S of the pin portion 3, during the revolving motion of the pin portion 3 around the central axis X, an arcuate heating conductor portion 17 a. And 17b are positions corresponding to the outer peripheral surface S of the pin portion 3 and the same region α in the circumferential direction of the pin portion 3 ₁ And the arcuate heating conductor portions 18a and 18b are at positions corresponding to the outer peripheral surface S of the pin portion 3 and the same region α in the circumferential direction of the pin portion 3. ₂ Will pass.
[0019]
Therefore, the outer peripheral surface S of the pin portion 3 is a region α that is the same region in the circumferential direction of the pin portion 3. ₁ And α ₂ Is heated intensively while ₁ , Α ₂ The intermediate region β is heated mainly by heat conduction. As shown in FIG. 11 (b), the hardened and hardened layer pattern P obtained as a result of such non-uniform heating has the regions α facing the heating conductor portions 17a and 17b and 18a and 18b, respectively. ₁ And α ₂ The hardened and hardened layer in the region β facing the arcuate heating conductors 17a and 18a and between the arcuate heating conductors 17b and 18b is relatively deep. A tendency for the depth to become relatively shallow appears. In particular, when the quench hardened layer depth is shallow or when the heating time is short, such a tendency appears very remarkably.
[0020]
Further, when the width of the pin portion 3 is wide, the lengths of the linear heating conductor portions 19a, 19b, 20a, 20a, 21b, 21b of the first and second heating coil portions 14a, 14b are increased, and the heating is performed. Since it contributes to the heating of the portion near the center of the outer peripheral surface S of the pin portion 3 (the central portion in the width direction) as a conductor, non-uniformity of the hardened and hardened layer depth hardly occurs. However, when heating the narrow pin portion 3, the length of the linear heating conductor portion is shortened, and induction heating is performed by the pair of arc-shaped heating conductor portions 17a and 18a, 17b and 18b. A portion near the center of the pin portion 3 in the width direction is not easily induction-heated, and as a result, the same tendency as the quench-hardened layer pattern P by the short-time heating described above appears.
[0021]
The same applies to the case of fillet R quenching (see FIGS. 12A and 12B) and the case of piece R quenching (see FIGS. 13A and 13B) for the above reasons. The tendency of
[0022]
Furthermore, since the high frequency induction heating coil 11 of the high frequency induction heating device 8 faces only approximately half of the upper circumference of the outer peripheral surface S of the pin portion 3, the outer peripheral surface S of the pin portion 3 immediately after induction heating is completed. Among these, there is a problem that the hardened and hardened layer depth differs between the upper surface side where the first and second heating coil portions 14a and 14b of the high-frequency induction heating coil 11 face each other and the lower surface side located on the open side. There is also. Such a phenomenon is likely to occur particularly in the case of heating for a short time, like the above-described tendency.
[0023]
In addition, since the above problems generate | occur | produce also for the same reason also about the high frequency induction heating apparatus 31, the description is abbreviate | omitted.
[0024]
The present invention has been made to solve such problems, and its purpose is to uniformly heat the outer peripheral surface of the pin portion or journal portion of the crankshaft over its entire circumference in a short time. An object of the present invention is to provide a high-frequency induction heating method and apparatus for a crankshaft that can eliminate unevenness in the depth of the hardened layer and obtain a good (uniform) hardened layer pattern.
[0025]
[Means for Solving the Problems]
In order to achieve the above-described object, in the present invention, when a plurality of high-frequency induction heating coils are installed on the outer peripheral surface of the pin portion or the journal portion of the crankshaft, a slight amount is provided on the outer peripheral surface of the pin portion or the journal portion. The heating coil portions of the plurality of high-frequency induction heating coils that are opposed to each other with a gap are arranged at positions offset from each other in the direction along the center axis of the pin portion or journal portion of the crankshaft, and under this state, While rotating the crankshaft around the center axis of the crankshaft and causing the plurality of high frequency induction heating coils to follow the outer peripheral surface of the pin portion or journal portion of the crankshaft, each of the plurality of high frequency induction heating coils By supplying a high frequency current, the outer peripheral surface of the pin portion or journal portion is subjected to high frequency induction. It is way.
In the present invention, a high-frequency current is supplied to each of the plurality of high-frequency induction heating coils simultaneously or with a time difference.
In the present invention, the magnitude of the high-frequency current supplied to the plurality of high-frequency induction heating coils can be arbitrarily adjusted.
Further, in the present invention, a high frequency induction heating coil is placed on the outer peripheral surface of the pin portion or the journal portion of the crankshaft via a guide member, and the crankshaft is rotated around the central axis of the crankshaft. While the high frequency induction heating coil is made to follow the outer peripheral surface of the pin portion or the journal portion, the outer peripheral surface of the pin portion or the journal portion is subjected to high frequency induction heating.
Further, the present invention comprises a plurality of high-frequency induction heating coils each having a heating coil portion disposed opposite to each other on different outer peripheral surfaces in the direction along the central axis of the pin portion or journal portion of the crankshaft, The heating coil portions of the plurality of high-frequency induction heating coils are arranged at positions offset from each other in the direction along the central axis of the pin portion or journal portion of the crankshaft, and the outer peripheral surfaces of the pin portion or journal portion are arranged on the plurality of high frequency portions. It is surrounded by the heating coil portion of the induction heating coil, and under this state, the outer peripheral surface of the pin portion or the journal portion is subjected to high frequency induction heating.
In the present invention, the heating coil portions of the plurality of high-frequency induction heating coils arranged opposite to the outer peripheral surface of the pin portion or journal portion of the crankshaft are configured in the same shape, and the plurality of high-frequency induction heatings are configured. The heating coil portion of the coil is perpendicular to the center line of the pin portion or journal portion of the crankshaft, and to an axis line perpendicular to the central axis at a bisection portion in the width direction of the pin portion or journal portion. On the other hand, they are arranged with a rotationally symmetric positional relationship.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4 and FIGS. 5 and 9. In FIG. 1 to FIG. 4, the same parts as those in FIG. 5 to FIG.
[0027]
FIG. 1 shows a high-frequency induction heating device 40 according to an embodiment of the present invention, and this high-frequency induction heating device 40 is held between a pair of side plates 41a and 41b made of brass or resin. The first high-frequency induction heating coil 30a, and the second high-frequency induction heating coil 30b held between the pair of side plates 42a and 42b made of brass or resin are provided.
[0028]
The two first and second high-frequency induction heating coils 30a and 30b provided in the high-frequency induction heating device 40 are coil bodies configured similarly to the high-frequency induction heating coil 30 of FIG. 9, that is, high-frequency induction heating coils. 30 is a coil body having a heating coil portion 29 configured in the same manner as 30 and is configured in the same shape.
[0029]
The two first and second high-frequency induction heating coils 30a and 30b having the same shape are arranged opposite to each other in the left and right positions, and a pair of arc-shaped heating conductors. The heating coil portion 29 of the first high-frequency induction heating coil 30a including the portions 33a and 33b, the linear heating conductor portion 34, and the pair of linear heating conductor portions 35a and 35b is connected to the central axis X of the crankshaft 1. The second high-frequency induction heating coil 30b has a heating coil portion 29, which is arranged to be opposed to a half portion on one side of the outer peripheral surface S of the pin portion 3 of the crankshaft 1 that is rotationally driven at the center. The crankshaft 1 is arranged so as to face the other half of the side surface of the outer peripheral surface S of the pin portion 3 of the crankshaft 1 that is driven to rotate about the central axis X of the crankshaft 1. It is. Thus, the arc-shaped heating conductor portions 33a and 33b of the heating coil portion 29 of each of the first and second high-frequency induction heating coils 30a and 30b are offset from each other in the direction along the central axis Y of the pin portion 3. In a state where they face each other, they are arranged along a circumference of a diameter corresponding to the diameter of the pin portion 3.
[0030]
Further, as shown in FIG. 1, the power supply leads 32a and 32b of the first high-frequency induction heating coil 30a are connected to the first high-frequency power source 12a via a high-frequency current supply transformer (not shown). At the same time, the power supply leads 32a and 32b of the second high-frequency induction heating coil 30b are connected to the second high-frequency power source 12b via a high-frequency current supply transformer (not shown). Thus, a predetermined high-frequency current is supplied to the first and second high-frequency induction heating coils 30a and 30b from the first and second high-frequency power supplies 12a and 12 via the transformers not shown in the drawing. It is configured.
[0031]
Further, between the pair of side plates 41a and 41b to which the first high-frequency induction heating coil 30a is attached, a pair of guide members 43a and 43b are attached at locations corresponding to the first high-frequency induction heating coil 30a. Between the pair of side plates 42a, 42b to which the second high-frequency induction heating coil 30b is attached, a pair of guide members 44a, 44b are attached at locations corresponding to the second high-frequency induction heating coil 30b. . Thus, the two first and second high-frequency induction heating coils 30a and 30b sandwich the central axis Y of the pin portion 3 to be heated via the guide members 43a, 43b and 44a, 44b. The outer circumferential surface S of the pin portion 3 is opposed to the outer circumferential surface S of the pin portion 3 with a slight gap therebetween, so that almost the entire circumference of the outer circumferential surface S of the pin portion 3 is the first and second high frequency induction heating coils 30a It is comprised so that it may be in the state surrounded by the heating coil part 29 of 30b.
[0032]
FIGS. 2A and 2B show an example of a cross section taken along line AA in FIG. 1 of the above-described high-frequency induction heating apparatus 40, and FIG. 2A shows high-frequency induction for flat quenching. FIG. 2B is a cross-sectional view taken along line AA of a high-frequency induction heating apparatus 40 including high-frequency induction heating coils 30a and 30b as a heating device, and FIG. 2B is a high-frequency induction as a high-frequency induction heating device for fillet R quenching. It is an AA line sectional view of high frequency induction heating device 40 provided with heating coils 30a and 30b.
[0033]
2 (a) and 2 (b), the common point regarding the positional relationship between the two first and second high-frequency induction heating coils 30a and 30b with respect to the pin 3 to be heated is that two high-frequency waves are used. At a location where the heating coil portion 29 of the induction heating coils 30a, 30b is orthogonal to the central axis Y of the pin portion 3 and bisects the width direction of the pin portion 3 (a bisected location in the width direction of the pin portion 3). The arc-shaped heating conductors 33a and 33b of the first high-frequency induction heating coil 30a and the second high-frequency induction heating coil are arranged with a rotationally symmetrical positional relationship around an axis Z orthogonal to the central axis Y of the pin portion 3. That is, the arc-shaped heating conductor portions 33a and 33b of 30b are set to be arranged at different positions in the direction along the central axis Y of the pin portion 3. More specifically, a region (a region between the pair of arc-shaped heating conductor portions 33a and 33b) sandwiched between the pair of arc-shaped heating conductor portions 33a and 33b, which is a component of the first high-frequency induction heating coil 30a, that is, the first Region β in which induction heating is difficult with only the high-frequency induction heating coil 30a ₁ Are arranged so that the arc-shaped heating conductor portion 33a of the other second high-frequency induction heating coil 30b faces each other, and a pair of circles that are components of the other second high-frequency induction heating coil 30b. A region sandwiched between the arc-shaped heating conductor portions 33a and 33b (a region between the pair of arc-shaped heating conductor portions 33a and 33b), that is, a region that is difficult to be induction-heated only by the heating coil portion 29 of the second high-frequency induction heating coil 30b. ₂ The two high frequency induction heating coils are arranged to face each other so that the arc-shaped heating conductor portion 33b of the first high frequency induction heating coil 30a faces each other. Therefore, the outer peripheral surface S of the pin portion 3 is almost entirely in the direction along the central axis Y (pin width direction), and the arc-shaped heating conductor portions 33a and 33b of the first and second high-frequency induction heating coils 30a and 30b. It will be in the state of facing. Note that α in FIG. ₁ ~ Α ₄ Is a heating area by each heating conductor part 33a, 33b).
[0034]
In this state, the crankshaft is driven to rotate about the central axis X, and the first and second high-frequency induction heating coils are applied to the pin portion 3 that revolves around the central axis X by a tracking mechanism (not shown). By supplying a high-frequency current to the second and second high-frequency induction heating coils 30a and 30b from the first and second high-frequency power supplies 12a and 12b, respectively, while following the 30a and 30b, the pins to be heated Each of the first and second high frequency induction heating coils 30a and 30b arranged with the arrangement relationship as described above with respect to the outer circumferential surface S of the portion 3 is induction-heated on the outer circumferential surface S of the pin portion 3. Difficult region β ₁ , Β ₂ Can be uniformly induction-heated so as to complement each other.
[0035]
In addition, the aspect of the induction heating mentioned above is the same also in the induction heating of the journal part 2 of the crankshaft 1. FIG.
[0036]
2 (c) shows another example of a cross-sectional view taken along the line AA in FIG. 1 of the above-described high-frequency induction heating device 40. The outer peripheral surface H of the journal portion 2a of the crankshaft 1 is shown on one side. A line of a high-frequency induction heating apparatus 40 including high-frequency induction heating coils 30a and 30b as a high-frequency induction heating apparatus for piece R quenching that forms a hardened and hardened layer continuous to the R part M and the thrust part N FIG. 5 is a cross-sectional view, and is particularly effective when induction hardening is performed on a journal portion 2a (see FIG. 5) where the counterweight portion is not adjacent to one side.
[0037]
The counterweight portion 4a is adjacent to the journal portion 2a on one side (right side in FIG. 5). When a hardened and hardened layer is formed continuously on the R portion M and the outer peripheral surface H on the counterweight 4a side. As shown in FIG. 1, high-frequency induction heating is performed in a state in which two first and second high-frequency induction heating coils 30a and 30b are opposed to each other from the left and right directions sandwiching the central axis X of the journal portion 2a. Done. That is, as shown in FIG. 2 (c), the arc-shaped heating conductor portion 33a of the first high-frequency induction heating coil 30a is disposed to face the outer peripheral surface H of the journal portion 2a with a slight gap therebetween. The arc-shaped heating conductor portion 33b of the high frequency induction heating coil 30a is disposed in the vicinity of the R portion M of the journal portion 2. The pair of arc-shaped heating conductor portions 33a and 33b of the second high-frequency induction heating coil 30b is used to heat the arc-shaped heating conductor portion 33a of the first high-frequency induction heating coil 30a as shown in FIG. It arrange | positions so that an area | region may be inserted | pinched, and it arrange | positions in the position corresponding to the area | region between the arc-shaped heating conductor parts 33a and 33b of the 1st high frequency induction heating coil 30a for the arc-shaped heating conductor part 33b of the 2nd high frequency induction heating coil 30b. Is done.
[0038]
The cross-sectional shape of the arc-shaped heating conductor portions 33a and 33b of the first high-frequency induction heating coil 30a is similar to that of the high-frequency induction heating coil constituting the high-frequency induction heating device for fillet R quenching, and the second high-frequency induction heating coil 30a The cross-sectional shape of the arc-shaped heating conductor portions 33a and 33b of the induction heating coil 30b is similar to that of the semi-open saddle type heating coil constituting the flat quenching high-frequency induction heating device (see FIG. 2C).
[0039]
As described above, when the high frequency induction heating of the journal portion 2a is performed, as in the case of the high frequency induction heating of the pin portion 3 shown in FIGS. 2 (a) and 2 (b), the two first and second high frequency inductions are performed. The arc-shaped heating conductor portions 33a and 33b of the heating coils 30a and 30b are all arranged at different positions in the direction along the central axis X of the journal portion 2. More specifically, a region sandwiched between a pair of arc-shaped heating conductors 33a and 33b that are constituent elements of the first high-frequency induction heating coil 30a, that is, a region γ that is difficult to be induction-heated only by the first high-frequency induction heating coil 30a. ₁ , Γ ₂ The arc-shaped heating conductor portions 33a and 33b of the second high-frequency induction heating coil 30b are disposed opposite to each other, and a pair of arc-shaped heating conductor portions 33a and 33b, which are constituent elements of the second high-frequency induction heating coil 30b, are sandwiched between them. Area γ that is difficult to be heated by induction ₃ Two first and second high-frequency induction heating coils 30a and 30b are arranged so that the arc-shaped heating conductor portion 33a of the first high-frequency induction heating coil 30a is opposed to the other. As a result, the outer peripheral surface H of the journal portion 2a is disposed substantially opposite to the respective arc-shaped heating conductor portions 33a and 33b of the first and second high-frequency induction heating coils 30a and 30b in the direction along the central axis X. It is configured to be in the state.
[0040]
Therefore, in this state, when the high frequency induction heating device 40 is made to follow the pin portion that performs the revolving motion in accordance with the rotational motion of the crankshaft 1 that is rotationally driven about the central axis X, the high frequency induction heating is performed. As described above, the outer peripheral surface H of the journal portion 2a is not easily induction-heated by the two first and second high-frequency induction heating coils 30a and 30b arranged in the same manner as in the case of flat quenching and fillet R quenching. Region γ ₁ , Γ ₂ , And γ ₃ Can be uniformly induction-heated so as to complement each other.
[0041]
Further, the above-described high-frequency device including two first and second high-frequency induction heating coils 30a and 30b as a high-frequency induction heating apparatus for piece R quenching that forms a hardened layer on the R portion M and the thrust portion N on one side described above. According to the induction heating device 40, when supplying a high-frequency current to these high-frequency induction heating coils 30a and 30b, the high-frequency current can be supplied simultaneously or with a time difference. Therefore, the outer peripheral surfaces H and R of the journal portion 2a. It is possible to adjust the depth of the hardened hardening layer formed in the part M.
[0042]
As described above, the journal portion 2a has a counterweight portion 4a on one side.
Since there is no counterweight portion on the other side, there is an extreme difference in heat mass (thermal mass), and the quench hardened layer depth in the R portion M on the counterweight 4a side where the heat mass is large is due to heat conduction. Since the heat is taken away, the hardened and hardened layer depth tends to be shallow, and the opposite side (the side without the counterweight) tends to be heated because the heat mass is small, and the hardened and hardened layer depth tends to increase.
[0043]
Therefore, in order to increase the quench hardened layer depth of the R portion M on the counterweight portion 4a side and reduce the quench hardened layer depth on the opposite side, first, the first high frequency induction heating coil 30a is provided with a second The high frequency current is supplied from the first high frequency power supply 12a, and then the high frequency current is supplied from the second high frequency power supply 12b to the second high frequency induction heating coil 30b after the required time has elapsed, so that the portion near the R portion M is first Since the temperature rise is started and the outer peripheral surface H is subsequently heated, a deep quench hardened layer can be obtained in the R portion M, and a shallow hardened layer can be obtained in the outer peripheral surface H.
[0044]
Also, high-frequency induction heating provided with two first and second high-frequency induction heating coils 30a and 30b as a high-frequency induction heating device for piece R quenching that forms a hardened layer on the R part M and the thrust part N on one side. The apparatus 40 can arbitrarily select and adjust the magnitude of the high-frequency current supplied to the high-frequency induction heating coils 30a and 30b, and therefore adjusts the outer peripheral surface of the journal portion 2a and the hardened layer depth of the R portion. Is possible.
[0045]
For example, when a deep quench hardened layer is formed on the R portion M of the journal portion 2a and a shallow hardened hard layer is formed on the outer peripheral surface H, the high frequency current supplied to the first high frequency induction heating coil 30a is used. May be relatively reduced depending on the magnitude of the high-frequency current supplied to the second high-frequency induction heating coil 30b. In this case, since the value of the induced current flowing in the vicinity of the R portion M is larger than the value of the induced current flowing in the outer peripheral surface H, a hardened and hardened layer deeper than the outer peripheral surface H is formed in the R portion M. can do.
[0046]
FIG. 3 shows a high-frequency induction heating device 50 according to another embodiment of the present invention, which is held between a pair of side plates 41a and 41b made of brass or resin. The first high-frequency induction heating coil 11a, and the second high-frequency induction heating coil 11b held between the pair of side plates 42a and 42b made of brass or resin are provided.
[0047]
The two first and second high-frequency induction heating coils 11a and 11b provided in the high-frequency induction heating device 50 are coil bodies configured similarly to the high-frequency induction heating coil 11 of FIG. 11 is a coil body having first and second heating coil portions 14a and 14b configured in the same manner as in FIG.
[0048]
The two first and second high-frequency induction heating coils 11a and 11b having the same shape are opposed to each other in the left and right positions, and are disposed opposite to each other. The heating coil portions 14a and 14b of the coil 11a are disposed so as to be opposed to the side half portion on one side of the outer peripheral surface S of the pin portion 3 of the crankshaft 1 that is driven to rotate about the central axis X of the crankshaft 1. The other side of the outer peripheral surface S of the pin portion 3 of the crankshaft 1 is configured and the heating coil portions 14a and 14b of the second high-frequency induction heating coil 11b are driven to rotate about the central axis X of the crankshaft 1. It is comprised so that it may oppose and arrange | position to the side half part. Thus, the heating coil portions 14a and 14b of the first and second high-frequency induction heating coils 11a and 11b are opposed to each other with an arrangement relationship offset from each other in the direction along the central axis Y of the pin portion 3. It is arranged along the circumference of the diameter corresponding to the diameter of the part 3.
[0049]
Further, as shown in FIG. 7, the power feed leads 16a and 16b of the first high-frequency induction heating coil 11a are connected to the first high-frequency power source 12a via a high-frequency current supply transformer (not shown). At the same time, the power supply leads 16a and 16b of the second high-frequency induction heating coil 11b are connected to a second high-frequency power source 12b via a high-frequency current supply transformer (not shown). Thus, a predetermined high-frequency current is supplied to the first and second high-frequency induction heating coils 11a and 11b from the first and second high-frequency power supplies 12a and 12 through the transformers (not shown). It is configured.
[0050]
Furthermore, in the high frequency induction heating device 50 of the present embodiment, the pair of side plates 41a and 41b to which the first high frequency induction heating coil 11a is attached include, for example, three ceramic or cemented carbide guide members 51a, The pair of side plates 42a and 42b to which the second high-frequency induction heating coil 11b is attached are fixed only at one place between the heating coil portions 14a and 14b of the second high-frequency induction heating coil 11b. The member 51d is fixed.
[0051]
4A shows a cross section taken along the line BB in FIG. 3, and a pair of arc-shaped heating conductor portions 17a, 18a and 17b of the heating coil portions 14a and 14b of the first high-frequency induction heating coil 11a, 18b are arranged in the vicinity of the R portion M of the pin portion 3, the arcuate heating conductor portions 17a and 17b are arranged on the same circumference, and the arcuate heating conductor portions 18a and 18b are arranged on the same circumference. Placed in.
[0052]
FIG. 4B shows a cross section taken along the line CC in FIG. 3, and a pair of arc-shaped heating conductor portions 17a and 18a of the first heating coil portion 14a of the second high-frequency induction heating coil 11b, The pair of arc-shaped heating conductor portions 17b and 18b of the second heating coil portion 14b are arranged at positions offset from each other on the outer peripheral surface S of the pin portion 3 so that the heating regions do not overlap each other. And the heating area | region by the 2nd high frequency induction heating coil 11b is arrange | positioned so that it may be located between the heating area | regions by the arc-shaped heating conductor parts 17a, 17b and 18a, 18b of the 1st high frequency induction heating coil 11a. .
[0053]
Therefore, the outer peripheral surface S of the pin part 3 and the vicinity of the R part M are all connected to the arc-shaped heating conductor parts 17a, 17b, 18a, 18b of the two first and second high-frequency induction heating coils 11a, 11b. Since it opposes, induction heating can be performed uniformly over the entire peripheral surface of the outer peripheral surface S.
[0054]
Further, as in the case of the piece R quenching described above, the high frequency current is supplied to the two high frequency induction heating coils 11a and 11b with a time difference, or the magnitude of the high frequency current supplied to each is appropriately selected. Thereby, the depth of the whole hardened layer can be arbitrarily adjusted by adjusting the temperature rising rate of the R part M and the outer peripheral surface S.
[0055]
Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications and changes can be made based on the technical idea of the present invention. For example, the shape of the first and second high-frequency induction heating coils 11a and 11b of the high-frequency induction heating device 50 according to another embodiment of the present invention is the same as that of the high-frequency induction heating coil 11 of the conventional high-frequency induction heating device. However, one of them may have the same shape as the high-frequency induction heating coil 30, and in the above-described embodiment, the first high-frequency induction heating coil disposed in the vicinity of both R parts M The depth of each part of the hardened and hardened layer is adjusted by adjusting the magnitude of the high-frequency current supplied to the second high-frequency induction heating coil 11b arranged opposite to the outer peripheral surface 11a. You may make it adjust the depth of each part of a hardening hardening layer by supplying the high frequency current of a different frequency to the 1st and 2nd high frequency induction heating coils 11a and 11b of a stand. In the above-described embodiments, all of the first and second high-frequency induction heating coils 30a, 30b, or 11a, 11b are used. However, three or more high-frequency induction heating coils are connected to the pin portion 3 or It is also possible to perform high-frequency induction heating in correspondence with the journal portion 2. In the above-described embodiment, induction hardening by high frequency induction heating has been described, but it can also be applied to induction tempering.
[0056]
【The invention's effect】
According to the present invention, the heating coil portions of a plurality of high-frequency induction heating coils that are opposed to the outer peripheral surface of the pin portion or journal portion of the crankshaft with a slight gap are provided as the pin portion or journal of the crankshaft. Since it is arranged to be offset from each other in the direction along the central axis of the part and is subjected to high-frequency induction heating, the width direction of the outer peripheral surface of the pin part or journal part to be heated (the pin part or journal part In the direction along the central axis), the heating coil portions of a plurality of high-frequency induction heating coils can be arranged to oppose almost the entire area of the outer peripheral surface, and the outer peripheral surface of the pin portion or journal portion depends on heat conduction over the entire peripheral surface. High-frequency induction heating can be performed uniformly without performing. Therefore, it is possible to form a good hardened and hardened layer with little variation in depth in a short time without extending the heating time for heat conduction, and the heat treatment time of the crankshaft can be shortened and produced. Can be improved.
[0057]
In the present invention according to claim 2, since the high frequency current is supplied to each of the plurality of high frequency induction heating coils simultaneously or with a time difference, the timing of supplying the high frequency current of each high frequency induction heating coil is set. By changing it, it is possible to arbitrarily adjust the hardened layer depth of each part of the hardened hardened layer, and to support a wide variety of quenching specifications without adjusting and replacing the high frequency induction heating coil Can do.
[0058]
Moreover, since the magnitude | size of the high frequency current supplied to these several high frequency induction heating coils can be adjusted arbitrarily, respectively, this invention of Claim 3 can adjust the high frequency current supplied to each high frequency induction heating coil. By changing the size, the hardened layer depth of each part of the hardened hardened layer can be adjusted arbitrarily, so it can be used for a variety of quenching specifications without the need for adjustment and replacement of high-frequency induction heating niils. can do.
[0059]
According to a fourth aspect of the present invention, there is provided a plurality of high-frequency induction heating having heating coil portions arranged to face each other on different outer peripheral surfaces in a direction along the central axis of the pin portion or journal portion of the crankshaft. Since the coil is provided, the heating coil portions of the plurality of high-frequency induction heating coils are arranged at positions offset from each other in the direction along the center axis of the pin portion of the crankshaft or the journal portion. The crankshaft pin portion or the entire peripheral surface of the journal portion can be heated uniformly without depending on heat conduction. Therefore, it is possible to form a good hardened and hardened layer with less variation in depth in a short time without extending the heating time for heat conduction, and the heat treatment time of the crankshaft can be shortened and produced. Can be improved.
[0060]
Further, according to the fifth aspect of the present invention, the heating coil portions of the plurality of high frequency induction heating coils disposed opposite to the outer peripheral surface of the pin portion or the journal portion of the crankshaft are configured in the same shape, and The heating coil portion of the high-frequency induction heating coil is perpendicular to the center line of the pin portion or journal portion of the crankshaft and is perpendicular to the central axis at a bisection portion in the width direction of the pin portion or journal portion. Because it is arranged so as to have a rotationally symmetric positional relationship with respect to the heating coil part of one high-frequency induction heating coil, the area that is difficult to heat is supplemented by the heating coil part of the other high-frequency induction heating coil. Therefore, high frequency induction heating can be performed and uniform heat treatment can be performed.
[Brief description of the drawings]
FIG. 1 is a side view of a high-frequency induction heating device used for implementing a high-frequency induction heating method for a crankshaft according to the present invention.
2 (a) and 2 (b) are enlarged cross-sectional views taken along line AA in FIG. 1, and FIG. 2 (c) is a diagram illustrating the case where the journal portion is subjected to high frequency induction heating. FIG.
FIG. 3 is a side view of an induction hardening apparatus according to another embodiment for carrying out the induction heating method for a crankshaft according to the present invention.
4A is an enlarged sectional view taken along line BB in FIG. 3, and FIG. 4B is an enlarged sectional view taken along line CC in FIG.
FIG. 5 is a perspective view of a crankshaft for a four-cylinder engine.
FIG. 6 is a side view of a conventional crankshaft high-frequency induction heating apparatus. .
7 is a schematic perspective view of a high-frequency induction heating coil that is a component of the high-frequency induction heating device of FIG. 6. FIG.
FIG. 8 is a side view of another conventional crankshaft high-frequency induction heating apparatus.
9 is a perspective view of another high-frequency induction heating coil that is a component of the high-frequency induction heating device of FIG. 8. FIG.
FIG. 10 is a cross-sectional view showing a preferable hardened and hardened layer formed on the outer peripheral surfaces of the pin part and the journal part.
FIG. 11 (a) is a diagram showing the arrangement relationship of high frequency induction heating coils when the outer peripheral surface of a pin portion is subjected to high frequency induction heating for flat quenching using a conventional high frequency induction heating device for a crankshaft. 6 is an enlarged cross-sectional view taken along the line DD in FIG. 6, and FIG. 11B is a cross-sectional view showing a hardened hardened layer pattern formed on the outer peripheral surface of the pin portion.
FIG. 12 (a) shows the arrangement relationship of high-frequency induction heating coils when the outer peripheral surface of the pin portion is subjected to high-frequency induction heating for fillet R quenching using a conventional crankshaft high-frequency induction heating device. Sectional drawing and FIG.12 (b) are sectional drawings which show the hardening hardening layer pattern formed in the outer peripheral surface of a pin part.
FIG. 13 (a) shows the arrangement relationship of the high-frequency induction heating coil when the outer peripheral surface of the pin portion is subjected to high-frequency induction heating for piece R quenching using a conventional crankshaft high-frequency induction heating device. Sectional drawing and FIG.13 (b) are sectional drawings which show the hardening hardening layer pattern formed in the outer peripheral surface of a pin part.
[Explanation of symbols]
1 Crankshaft for 4-cylinder engine
2 (2a-2e) Journal part
3 (3a-3d) Pin part
11a First high frequency induction heating coil
11b Second high frequency induction heating coil
12a First high frequency power supply
12b Second high frequency power supply
14a First heating coil portion
14b Second heating coil portion
17a, 17b, 18a, 18b Arc-shaped heating conductor
29 Heating coil part
30a First high frequency induction heating coil
30b Second high frequency induction heating coil
43a, 43b, 44a, 44b Guide member
51a-51d guide member
H Outer surface of journal
S Pin outer peripheral surface
X Center axis of crankshaft
Y pin center axis

Claims

When installing a plurality of high frequency induction heating coils on the outer peripheral surface of the pin portion or the journal portion of the crankshaft, the plurality of high frequency inductions arranged to face the outer peripheral surface of the pin portion or the journal portion with a slight gap therebetween. The heating coil portion of the heating coil is arranged at a position offset from each other in the direction along the central axis of the pin portion or journal portion of the crankshaft,
Under this state, the crankshaft is rotated about the center axis of the crankshaft and the plurality of high frequency induction heating coils are made to follow the outer peripheral surface of the pin portion or journal portion of the crankshaft, High frequency induction heating is performed on the outer peripheral surface of the pin portion or the journal portion by supplying a high frequency current to each of the high frequency induction heating coils.
A method for induction heating of a crankshaft characterized by

The high frequency induction heating method for a crankshaft according to claim 1, wherein a high frequency current is supplied to each of the plurality of high frequency induction heating coils simultaneously or with a time difference.

The high frequency induction heating method for a crankshaft according to claim 1, wherein the magnitude of the high frequency current supplied to the plurality of high frequency induction heating coils can be arbitrarily adjusted.

A high frequency induction heating coil is placed on the outer peripheral surface of the pin portion or journal portion of the crankshaft via a guide member, and the crankshaft is rotated about the central axis of the crankshaft so that the high frequency induction heating coil is In the high-frequency heating device for the crankshaft, the outer peripheral surface of the pin portion or the journal portion is heated by high-frequency induction while following the outer peripheral surface of the pin portion or the journal portion.
A plurality of high-frequency induction heating coils each having a heating coil portion disposed opposite to each other on different outer peripheral surfaces in the direction along the central axis of the pin portion or journal portion of the crankshaft;
The heating coil portions of the plurality of high frequency induction heating coils are arranged at positions offset from each other in a direction along the center axis of the pin portion or journal portion of the crankshaft, and the outer peripheral surfaces of the pin portion or journal portion are arranged in the plurality of the plurality of high frequency induction heating coils. Surrounded by the heating coil portion of the high-frequency induction heating coil, and under this state, the outer peripheral surface of the pin portion or journal portion was subjected to high-frequency induction heating,
A high-frequency induction heating device for crankshafts.

The heating coil portions of the plurality of high frequency induction heating coils disposed opposite to the outer peripheral surface of the pin portion or journal portion of the crankshaft are configured in the same shape, and the heating coil portions of the plurality of high frequency induction heating coils are , A position that is orthogonal to the center line of the pin portion or journal portion of the crankshaft and rotationally symmetric with respect to an axis line that is orthogonal to the central axis at a bisection portion in the width direction of the pin portion or journal portion 5. The high frequency induction heating device for a crankshaft according to claim 4, wherein the high frequency induction heating device is arranged in a relationship.