JP3408644B2 - Parts press-fit camshaft - Google Patents
Parts press-fit camshaftInfo
- Publication number
- JP3408644B2 JP3408644B2 JP27032494A JP27032494A JP3408644B2 JP 3408644 B2 JP3408644 B2 JP 3408644B2 JP 27032494 A JP27032494 A JP 27032494A JP 27032494 A JP27032494 A JP 27032494A JP 3408644 B2 JP3408644 B2 JP 3408644B2
- Authority
- JP
- Japan
- Prior art keywords
- cam
- camshaft
- press
- gear
- shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000000463 material Substances 0.000 claims description 22
- 229910000831 Steel Inorganic materials 0.000 claims description 9
- 239000010959 steel Substances 0.000 claims description 9
- 239000000956 alloy Substances 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 4
- 230000006698 induction Effects 0.000 claims description 3
- 238000005255 carburizing Methods 0.000 claims description 2
- 238000010791 quenching Methods 0.000 claims description 2
- 230000000171 quenching effect Effects 0.000 claims description 2
- 238000010008 shearing Methods 0.000 claims description 2
- 238000005096 rolling process Methods 0.000 description 14
- 238000004519 manufacturing process Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 6
- 238000005219 brazing Methods 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 5
- 238000009661 fatigue test Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 238000003466 welding Methods 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000003252 repetitive effect Effects 0.000 description 3
- 102200082816 rs34868397 Human genes 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
Landscapes
- Valve-Gear Or Valve Arrangements (AREA)
- Gears, Cams (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、エンジンのカム軸に複
数の部品を圧入しながら周方向にかみ合い歯を創製し、
該部品より軸に必要なトルクを伝えるに十分な結合力を
付与できるように材料の硬度範囲を選定したカムシャフ
トに関するものである。
【０００２】
【従来の技術】カム軸に、別体のカムピース、あるいは
歯車を嵌合して製造されるカムシャフトについては、従
来よりカム軸の一部を太くし軸線方向に単数または複数
のキー溝を設け、カムピースあるいは歯車の嵌合孔内面
に単数または複数のキー突条を形成し、これらのキー溝
とキー突条をかみ合わせて圧入またはロウ剤充填により
固定する方法が公知である。
【０００３】しかしこのような製造方法では、カム軸と
カムピース及び歯車の嵌合部や組合わせ位置決めに高い
寸法精度が要求されるため、これらの部品の製造に多く
の手間がかかり、生産性が低下し、コスト高の要因にな
っていた。これらの問題に対し、カム軸にカムピースを
圧入しながら軸の周方向にかみ合い歯を創製する方法
が、特開平２−１５０５４４号に紹介されているので、
これについて図６〜図８に基づいて説明する。
【０００４】図中符号１は中空金属製シャフトで、この
シャフト１の各カム固定箇所１Ａには、焼結合金製カム
２（１つのみ図示）が互いに離間して所定角度で固定さ
れている。前記カム固定箇所１Ａには、図８に示すよう
に、カムピース固定に先立って多数の溝３が螺旋状また
は同心円状に周方向に転造され、これにより溝３同士の
中間部が盛り上がり、突条４となっている。これら突条
４の外径Ｄ２は、シャフト本体部１Ｂの外径Ｄ１の１０
１〜１１０％程度とされることが望ましい。この範囲よ
り小さいと十分なカムピースの固定強度が得られず、ま
たこれより大きいと円滑な圧入が困難になりカム位置精
度が低下する。
【０００５】一方、カムピース２には、シャフト本体部
１Ｂの外径Ｄ１よりも大きく、突条４の外径Ｄ２より小
さい内径Ｄ３を有する円柱形のシャフト孔５が軸線方向
に形成されている。このシャフト孔５の内面には、軸線
方向に延びるキー突条６が周方向等間隔に（図６の場合
は８つ）形成され、各キー突条６の断面はエッジを有す
る矩形状とされている。これらのキー突条６の突出量
は、その頂点面６Ａでの内径Ｄ４が次式の関係を満たす
ようになっている。
Ｄ１≦Ｄ４＜Ｄ３＜Ｄ２
一方、円周方向の突条４の幅や断面形状は、カムピース
２をシャフト１に圧入する際に、該突条４がキー状の突
条６により良好に切削されるように考慮すべきである。
【０００６】カムピース２をシャフト１に固定するに
は、シャフト１の一端側のカム固定部１Ａから順に、溝
３及び突条４の転造と、キー突条を有するカム２の圧入
とを交互に繰り返していく。すると、図８に示すよう
に、各キー突条６が先端エッジ６Ａで円周方向の突条４
を順に切り欠いてキー溝７を形成すると同時に、キー突
条６を除くシャフト孔５の前端エッジ５Ａが各突条４の
頭頂部を全長に亙って僅かに切り欠いていく。
【０００７】したがって圧入後は、キー突条６は自ら形
成したキー溝７に隙間なく嵌合するうえ、各突条４の頭
頂部がシャフト孔５の内面に圧着され、カムピースが強
固に固定される。なお、圧入が完了したままの状態でも
このカムシャフトは使用可能であるが、強度および信頼
性をさらに高めるために、カムピース２とシャフト１と
の空隙にロウ剤を充填したり、カムピース２とシャフト
１をスポット溶接してもよい。
【０００８】上記構成からなるカムシャフトでは、シャ
フト１にカムピース２を圧入するだけでカム２を任意の
角度位置に固定できるため、組み立て作業が極めて容易
で手間がかからず生産性を高め、その分製造コスト低下
が図れる。また、カムピース２のキー突条６は自らが切
り開いたキー溝７に密着状態で嵌合するから、固定力が
極めて大きい上がたつきが全くなく、高い位置精度が容
易に実現できる。さらに圧入後のカムピース２には、従
来の圧入型シャフトほどの大応力が加わらないため、低
コストで寸法精度の高い焼結体製のカムピース２を使用
することができ、この点からも低コスト化および高精度
化が図られる。
【０００９】
【発明が解決しようとする課題】従来の技術では組立後
の結合強度に対する部品の仕様（部品サイズに対応する
材質、シャフト転造部とこれに結合するカムピース内径
部スプラインの硬度等）が示されてないため、カムピー
スの材質は必要以上の高級材料（超硬合金等）が使用さ
れていた。また、従来例においては、カムピースがシャ
フトに圧入されるとき、カムピース内径部スプラインが
シャフト転造部の膨出部を剪断して嵌合するため、結合
部に歪みに対応する弾性が殆ど残らず、繰り返し荷重が
懸かるとシャフト側が直ぐにへたり、隙間が生じる可能
性がある。
【００１０】これの防止策として、さらにカムピース２
とシャフト１との空隙に金属ロウ剤を充填したり、カム
ピース２とシャフト１をスポット溶接で結合を高めた
り、カムピース内径部スプラインに僅かなテーパーを設
けたりする手法が必要であった。低コスト化のために一
般焼結材（ＪＩＳ ＳＭＦ５種あるいは８種等）でも、
ロウ剤やスポット溶接等の補助手段を使用せずに、高い
結合強度が得られる材質のスペックが課題であった。
【００１１】本発明の目的は、台形溝を転造したカム軸
に、内筒面に軸方向のスプラインを設けたカムピース及
び歯車を圧入結合して製造されるカムシャフトにおい
て、各部品の仕様（カム軸製造部とこれに結合するカム
ピース及び歯車の内径部スプライン硬度等）を限定する
ことにより通常入手可能でじん性があり取扱容易なＳ４
５Ｃ材の使用を可能とすると共に、歯車及びカムピース
に焼結合金材料をも使用可能とし加工工数の減少を実現
でき生産性が高く製造コストも低く、しかも耐久性の大
きい部品圧入カムシャフトを提供するにある。
【００１２】
【課題を解決するための手段】本発明の部品圧入カムシ
ャフトは、カムピース及び歯車の取付け位置に圧入幅に
亙って多数の円周方向の台形溝を転造した鋼材製のカム
軸に、内筒面に軸方向のスプラインを設けた前記カムピ
ース及び歯車を圧入結合して製造されるカムシャフトに
おいて、転造部硬度（Ｈｓ）がＨＲＣ11〜20の鋼材製カ
ム軸と、これに圧入される前記カムピース及び歯車は焼
結合金材料とし、 前記圧入されるカムピース及び歯車を
高周波焼入若しくは浸炭焼き入れにより表面硬化を行
い、表面硬化させた内周面表面硬度（Ｈｋ）がカム軸の
材料の硬度よりＨＲＣ10〜40大きい範囲の〔Ｈｋ＝Ｈｓ
＋ＨＲＣ（10〜40）〕とし、前記カムピース及び歯車の
前記スプラインに施された面取り部側からのカム軸への
圧入結合により、前記カムピース及び歯車のスプライン
端がカム軸の転造膨出部を塑性変形及び剪断せしめてか
み合い歯を創製するように構成されたことを特徴とす
る。特に本発明は転造部硬度（Ｈｓ）がＨＲＣ11〜20の
鋼材製カム軸圧入されるカムピース及び歯車を焼結合金
材料とすることにより課題の加工工数減少がより一層図
られる。
【００１３】
【作用】上記のように、転造部硬度（Ｈｓ）がＨＲＣ11
〜20以下の鋼材製カム軸に、同カム軸の材料の硬度より
ＨＲＣ10〜40大きい範囲の〔Ｈｋ＝Ｈｓ＋ＨＲＣ（10〜
40）〕内周面硬度（Ｈｋ）を有するカムピース及び歯車
を、スプラインの面取り側よりカム軸に圧入すれば、カ
ムピース及び歯車のスプライン端がカム軸の転造膨出部
を塑性変形及び剪断しながらかみ合い歯を創製し圧入結
合される。各スプラインの歯の結合部全部に塑性変形に
伴う弾性歪みと応力が残り、これがシャフトとカムピー
ス及び歯車のスプライン部の結合を強固とし、シャフト
に対する繰り返しトルク荷重を分散して受け持つことが
できる。
【００１４】
【実施例】以下図１〜５を参照し本発明の一実施例につ
いて説明する。本発明は、産業用エンジンにおけるギヤ
駆動方式のカムシャフトに適用した第１実施例である。
図１〜図４は、カム軸の所定位置に、転造により元径よ
り膨出した多数の環状部を形成し、これにカム部品を圧
入しながら軸の周方向にかみ合い歯を創製する方法によ
り製造された、歯車付きカムシャフト１０の側面図（図
１）、正面図（図３）及びかみ合い歯創製部の詳細図
（図２、図４）を示す。鋼材カム軸１１の転造部硬度
（Ｈｓ）をＨＲＣ11〜20とし、これに圧入される前記カ
ムピース１２，１３及び歯車１４は、その内周面硬度
（Ｈｋ）がカム軸１１の材料の硬度よりＨＲＣ10〜40
（硬度バランスΔＨと称す。）大きい範囲の〔Ｈｋ＝Ｈ
ｓ＋ＨＲＣ（10〜40）〕材料とする。
【００１５】カム軸１１のカムピース１２，１３及び歯
車１４の固定箇所には、図１に示すように、これらの部
品の圧入固定に先立って、多数の溝が螺旋状または同心
円状に周方向に転造される。上記の硬度の鋼材であれ
ば、この転造加工は容易である。この転造加工により、
溝同士の間が盛り上がり、台形の突出部１１ａとなる。
この突出部１１ａの外径は当然カム軸１１の外径より大
きくなる。
【００１６】一方、カムピース１２，１３及び歯車１４
には、カム軸１１の外径Ｄ1 よりも大きく、突出部１１
ａの外径Ｄ2 より小さい内径を有する軸孔が明けられ、
この軸孔には、軸線方向のスプライン１２ａが形成され
ている。この軸孔のスプライン１２ａの溝底径Ｄ3 は、
カム軸の転造突出部１１ａの径Ｄ4 より大きく形成され
ている。（このカム軸１１の径Ｄ1 、カム軸の転造突出
部１１ａの径Ｄ2 、スプライン１２ａの溝底径Ｄ3 及び
内径Ｄ4 の関係は、従来例において説明した関係寸法、
Ｄ１≦Ｄ４＜Ｄ３＜Ｄ２と同様である。）
【００１７】カムピース１２，１３及び歯車１４のスプ
ライン部は、図２で示したように、片側に面取り部１２
ｂが形成されている。カムピース１２，１３及び歯車１
４を、スプラインの面取り１２ｂ側よりカム軸１１の転
造突出部１１ａに圧入すれば、カムピース及び歯車のス
プライン端の面取り部１２ｂが、カム軸の転造突出部１
１ａを塑性変形及び剪断しながら、かみ合い歯を創製し
（図２及び図４のように）、圧入結合される。上記で示
したカムピース１２，１３及び歯車１４の鋼材硬度であ
れば、カム軸１１材料との硬度差が十分であり、この圧
入かみ合い歯創製の工程において、スプライン１２ａが
変形したり、欠けたりする虞れは無い。
【００１８】そして上記の鋼材を使用し、指定された範
囲の硬度差に処理されてあれば、各スプラインの歯の結
合部全体に塑性変形に伴う弾性歪みと応力が残り、カム
シャフト１０に対してトルク荷重がかかっても、スプラ
イン１２ａの各かも合い歯がこの荷重を分散して受け持
ち、カム軸１１とカムピース１２，１３及び歯車１４の
スプライン部に空隙を生じることを防止し、カムシャフ
ト１０に対する繰り返しトルク荷重に対して、がたつき
のない結合を維持することができる。そしてこのカムシ
ャフト１０は、圧入を完了したままの状態で使用可能で
ある（ロー接着やスポット溶接は不要）。
【００１９】カムピース１２，１３及び歯車１４をカム
軸１１に固定する工程順は、カム軸１１の一端側から順
に、歯車１４の圧入位置の転造突出部１１ａの転造と、
歯車１４の圧入、カムピース１３の位置の転造、カムピ
ース１３の圧入、カムピース１２の位置の転造、カムピ
ース１２の圧入の順に作業を交互に繰り返し、図１に示
すようなカムシャフト１０が完成する。
【００２０】上記構成からなるカムシャフト１０では、
カム軸１１にカムピース１２，１３及び歯車１４を圧入
するだけで、カム軸１１の任意の角度位置に固定できる
ため、組み立て作業が極めて容易で手間がかからず、生
産性を高め、製造コストも低下し、高い位置精度が容易
に実現できる。さらに、上述のようにトルク荷重を分散
して受け持つので、従来の圧入型カムシャフトほどに円
周方向の締付応力が加わらないため、低コストで寸法精
度の高い焼結合金製のカムピースを使用することがで
き、この点からも低コスト化および高精度化が図られ
る。
【００２１】上述の如く、カムピース、ギヤ共に、焼結
成形部品の内径スプラインの硬度（Ｈｋ）とシャフト転
造部の硬度（Ｈｓ）との差（硬度パランスΔＨ）により
結合強度は左右され、この硬度バランスの最適値は、Ｈ
ｋ＝Ｈｓ＋ＨＲＣ（10〜40）であり、参考に以下本発明
において指定した材料硬度のテストピースによる圧入繰
り返し荷重試験の成績を述べる。
【００２２】テストピースの材質、熱処理、硬度、軸径
等、及び組合せ
（１）カム軸：Ｓ４５Ｃ 標準熱処理 硬度：ＨＲＢ
90〜98（ＨＲＣ11〜20）
軸径：１５ｍｍ 歯車：ＪＩＳ ＳＭＦ５種高周波焼
入 硬度：ＨＲＣ39〜42 結合部幅：８ｍｍ 歯
車内径とカム軸転造部外形の差（圧入代）：０．３４〜
０．４２
（２）カム軸：Ｓ４５Ｃ 標準熱処理 硬度：ＨＲＢ
90〜98（ＨＲＣ11〜20）
軸径：１５ｍｍ カムピース：ＪＩＳ ＳＭＦ８種浸
炭 硬度：ＨＲＣ41〜46 結合部幅：８ｍｍ カ
ムピースとカム軸転造部外形の差（圧入代）：０．３４
〜０．４２
【００２３】テストピース（１）の組合わせにおいて、
繰り返しトルク荷重１０ｋｇ−ｍを負荷し、繰り返し回
数１×１０7 の疲労試験を行った結果は、疲労試験を行
ったテストピースと疲労試験を行わなかった同じテスト
ピースとの比較において、歯車をカム軸から抜き取る抜
出荷重の差がなく、上記の圧入組合わせカムシャフトは
緩みを生じない堅固な結合をしているものと判定され
た。テストピース（２）の組合わせにおいては、圧入組
合わせの結合強度は（１）の場合と同等であるが、カム
形状には比較的薄肉の環状部があるので、焼結合金製の
部品としては、圧入のときにカムピースの環状部に働く
張力による破断が気になるところである。
【００２４】しかし上記のようにカムピースと歯車の材
料の硬度はＨＲＣ45付近に抑えてあるので、伸びに余裕
があり、エンジンの実機耐久テストの結果からも十分に
張力に耐える余裕のあることが検証できた。図５に疲労
試験の結果を示す。図より硬度バランスΔＨがΔＨ＝Ｈ
ＲＣ10〜40の範囲では限界繰り返し数１０7 の繰り返し
荷重テストでも損傷がないのがわかる。
【００２５】
【発明の効果】カム軸にカム部品を圧入しながら軸の周
方向にかみ合い歯を創製する従来工法と、上記に示した
材質の熱処理硬度の適用によりＪＩＳ ＳＭＦ５種ある
いは８種の焼結材料使用が可能となり、圧入の結合強度
は十分であり、カムピースとカム軸との空隙に金属ロウ
剤を充填したり、カムピースとカム軸とをスポット溶接
で結合を高めたり、カムピース内径部スプラインに僅か
なテーパーを設けたりする手法は必要なく、さらにカム
及びギヤを高精度の焼結成形体とすることにより、組立
後の機械加工を省けるため大幅にコストを低減できるカ
ムシャフトの製作が可能となる。
【００２６】又カム軸の材料として、通常入手可能でじ
ん性がよくしかも取扱容易な機械構造用炭素鋼ＪＩＳ
Ｇ ４０５１のＳ４５Ｃ材も使用可能でありさらにコス
トの低減をはかることができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the creation of a meshing tooth in the circumferential direction while press-fitting a plurality of parts into a camshaft of an engine.
The present invention relates to a camshaft whose hardness range is selected so that a sufficient coupling force can be imparted from the component to a shaft to transmit necessary torque. 2. Description of the Related Art For a camshaft manufactured by fitting a separate cam piece or a gear to a camshaft, a part of the camshaft is conventionally made thicker and one or more keys are provided in the axial direction. A method is known in which a groove is provided, one or a plurality of key ridges are formed on the inner surface of a fitting hole of a cam piece or a gear, and these key grooves and the key ridge are engaged with each other and fixed by press-fitting or filling with a brazing agent. However, in such a manufacturing method, high dimensional accuracy is required for the positioning of the cam shaft, the cam piece, and the fitting portion and the combination of the gears. Therefore, manufacturing of these parts requires a lot of labor and productivity. It has been a factor of high cost. To solve these problems, Japanese Patent Application Laid-Open No. 2-150544 discloses a method for creating meshing teeth in the circumferential direction of a cam shaft while press-fitting a cam piece into the cam shaft.
This will be described with reference to FIGS. In FIG. 1, reference numeral 1 denotes a hollow metal shaft, and a sintered alloy cam 2 (only one is shown) is fixed to each cam fixing portion 1A of the shaft 1 at a predetermined angle apart from each other. . As shown in FIG. 8, a large number of grooves 3 are spirally or concentrically rolled in the circumferential direction at the cam fixing portion 1A prior to fixing the cam piece. Article 4. The outer diameter D2 of these ridges 4 is 10 times the outer diameter D1 of the shaft body 1B.
It is desirable to set it to about 1 to 110%. If it is smaller than this range, sufficient fixing strength of the cam piece cannot be obtained, and if it is larger than this, smooth press-fitting becomes difficult and the cam position accuracy decreases. On the other hand, a cylindrical shaft hole 5 having an inner diameter D3 larger than the outer diameter D1 of the shaft body 1B and smaller than the outer diameter D2 of the ridge 4 is formed in the cam piece 2 in the axial direction. On the inner surface of the shaft hole 5, key projections 6 extending in the axial direction are formed at equal intervals in the circumferential direction (eight in the case of FIG. 6), and the cross section of each key projection 6 is a rectangular shape having an edge. ing. The protrusion amount of the key ridges 6 is such that the inner diameter D4 at the vertex surface 6A satisfies the following relationship. D1 ≦ D4 <D3 <D2 On the other hand, when the cam piece 2 is press-fitted into the shaft 1, the width and the cross-sectional shape of the ridge 4 are favorably cut by the key-shaped ridge 6. Should be taken into account. In order to fix the cam piece 2 to the shaft 1, the rolling of the groove 3 and the ridge 4 and the press-fitting of the cam 2 having the key ridge are alternately performed in order from the cam fixing portion 1A at one end of the shaft 1. Repeat. Then, as shown in FIG. 8, each key ridge 6 is provided with a circumferential ridge 4 at the leading edge 6A.
Are cut in order to form the key groove 7, and at the same time, the front end edge 5A of the shaft hole 5 excluding the key ridge 6 slightly cuts the top of each ridge 4 over its entire length. Therefore, after press-fitting, the key ridges 6 fit into the key grooves 7 formed by themselves without any gap, and the top of each ridge 4 is pressed against the inner surface of the shaft hole 5 to firmly fix the cam piece. You. The camshaft can be used even when the press-fitting is completed. However, in order to further increase the strength and reliability, the gap between the campiece 2 and the shaft 1 is filled with a brazing agent, 1 may be spot-welded. In the camshaft having the above structure, the cam 2 can be fixed at an arbitrary angular position only by press-fitting the cam piece 2 into the shaft 1, so that the assembling work is extremely easy, the labor is reduced, and the productivity is improved. The manufacturing cost can be reduced. In addition, since the key ridges 6 of the cam piece 2 are fitted in the key groove 7 opened by itself in a close contact state, the fixing force is extremely large, there is no rattling, and high positional accuracy can be easily realized. Further, since a large stress is not applied to the cam piece 2 after the press-fitting as compared with the conventional press-fit type shaft, the cam piece 2 made of a sintered body having low cost and high dimensional accuracy can be used. And higher precision are achieved. In the prior art, the specifications of parts with respect to the bonding strength after assembly (materials corresponding to the part size, hardness of the shaft rolled portion and the spline hardness of the cam piece inner diameter portion connected thereto, etc.) Is not shown, so that a higher quality material than necessary (such as a cemented carbide) was used as the material of the cam piece. Further, in the conventional example, when the cam piece is press-fitted into the shaft, the spline of the inner diameter portion of the cam piece shears the bulged portion of the rolled portion of the shaft and fits the spline portion. However, if a repeated load is applied, the shaft side may be bent immediately or a gap may be generated. As a measure to prevent this, the cam piece 2
It is necessary to fill the gap between the shaft and the shaft 1 with a metal brazing agent, to enhance the connection between the cam piece 2 and the shaft 1 by spot welding, and to provide a slight taper in the spline of the inner diameter of the cam piece. In order to reduce the cost, general sintered materials (JIS SMF 5 or 8 etc.)
There has been a problem in the specification of a material capable of obtaining high bonding strength without using an auxiliary means such as a brazing agent or spot welding. An object of the present invention is to provide a camshaft manufactured by press-fitting a cam piece and a gear provided with an axial spline on an inner cylindrical surface to a camshaft having a trapezoidal groove formed therein, and to specify the specifications of each part ( S4 which is usually available, has toughness and is easy to handle, by limiting the camshaft manufacturing part and the spline hardness of the inner diameter part of the cam piece and the gear connected thereto.
The use of 5C material and the use of a sintered alloy material for gears and cam pieces can reduce the number of processing steps, providing a high-productivity, low-cost, and highly durable component press-fit camshaft. To be. The component press-fitting camshaft of the present invention is a steel cam having a number of circumferential trapezoidal grooves rolled over the press-fitting width at the mounting positions of the cam piece and the gear. In a camshaft manufactured by press-fitting the cam piece and the gear in which an axial spline is provided on an inner cylindrical surface on a shaft, a rolled portion hardness (Hs) of a steel material having an HRC of 11 to 20 is used.
The cam shaft and the cam piece and gear pressed into it are
The cam piece and the gear to be press-fitted are made of a bonding metal material.
Surface hardening by induction hardening or carburizing quenching
[Hk = Hs], where the surface hardness (Hk) of the hardened inner peripheral surface is HRC10 to 40 larger than the hardness of the material of the camshaft.
+ HRC (10-40)] and the cam piece and the gear
Configuration by press-fitting coupling to the cam shaft from the chamfered portion which has been subjected to the spline, as splined end of the cam piece and the gear to create a tooth meshing with plastically deformed and shear the rolling bulging portion of the cam shaft It is characterized by having been done. In particular, the present invention can further reduce the number of processing steps by using a sintered alloy material for a cam piece and a gear to be press-fitted into a steel camshaft having a rolled portion hardness (Hs) of HRC 11 to 20. As described above, the hardness of the rolled portion (Hs) is HRC11.
[Hk = Hs + HRC (10 to 10) in a range of HRC10 to 40 larger than the hardness of the material of the camshaft.
40)] If a cam piece and a gear having an inner peripheral surface hardness (Hk) are pressed into a cam shaft from a chamfered side of a spline, the spline ends of the cam piece and the gear plastically deform and shear the rolled bulging portion of the cam shaft. A meshing tooth is created and press-fitted. Elastic strain and stress due to plastic deformation remain at all the joints of the teeth of each spline, which strengthens the connection between the shaft, the cam piece and the spline of the gear, and can distribute and bear the repetitive torque load on the shaft. An embodiment of the present invention will be described below with reference to FIGS. The present invention is a first embodiment applied to a gear drive type camshaft in an industrial engine.
FIGS. 1 to 4 show a method of forming a large number of annular portions swelling from the original diameter by rolling at predetermined positions of a camshaft, and forming a meshing tooth in a circumferential direction of the shaft while press-fitting a cam part into the annular portion. 1 shows a side view (FIG. 1), a front view (FIG. 3), and a detailed view (FIGS. 2 and 4) of a meshing tooth forming portion of the camshaft 10 with gears manufactured by the method of the present invention. The hardness of the rolled portion (Hs) of the steel camshaft 11 is HRC11-20, and the cam pieces 12, 13 and the gear 14, which are press-fitted therein, have inner peripheral surface hardness (Hk) which is smaller than the hardness of the material of the camshaft 11. HRC10-40
(Referred to as hardness balance ΔH). [Hk = H
s + HRC (10 to 40)]. As shown in FIG. 1, a number of grooves are spirally or concentrically formed in the circumferential direction of the cam shaft 11, at the positions where the cam pieces 12, 13 and the gear 14 are fixed. Rolled. With a steel material having the above hardness, this rolling process is easy. By this rolling process,
The space between the grooves rises to form a trapezoidal projection 11a.
The outer diameter of the projection 11a is naturally larger than the outer diameter of the camshaft 11. On the other hand, the cam pieces 12, 13 and the gear 14
The larger than the outer diameter D 1 of the cam shaft 11, the protruding portion 11
a shaft hole having an inner diameter smaller than the outer diameter D 2 of
An axial spline 12a is formed in the shaft hole. The groove bottom diameter D 3 of the spline 12a of this shaft hole is
It is formed larger than the diameter D 4 of the rolling protrusion 11a of the cam shaft. (The diameter D 1 of the cam shaft 11, rolling relationship protrusion diameter D 2 of 11a, the groove bottom diameter D 3 and the inner diameter D 4 of the spline 12a of the cam shaft, the relationship dimensions described in the prior art,
It is the same as D1 ≦ D4 <D3 <D2. As shown in FIG. 2, the splines of the cam pieces 12, 13 and the gear 14 have chamfers 12 on one side.
b is formed. Cam pieces 12, 13 and gear 1
4 is pressed into the rolling projection 11a of the cam shaft 11 from the spline chamfering 12b side, the cam piece and the spline end chamfering portion 12b of the gear become the rolling projection 1 of the cam shaft.
While plastically deforming and shearing 1a, a meshing tooth is created (as in FIGS. 2 and 4) and press-fitted. If the hardness of the steel material of the cam pieces 12, 13 and the gear 14 described above is sufficient, the hardness difference from the material of the camshaft 11 is sufficient, and the spline 12a is deformed or chipped in the press-fit meshing process. There is no fear. If the above-mentioned steel material is used and processed to a hardness difference within a specified range, elastic distortion and stress due to plastic deformation remain in the entire joint portion of the teeth of each spline, and the camshaft 10 Even if a torque load is applied, the spur teeth of the spline 12a disperse and bear this load to prevent a gap from being formed in the spline portions of the camshaft 11, the cam pieces 12, 13 and the gear 14, thereby preventing the camshaft 10 Can be maintained without any backlash against the repeated torque load on. The camshaft 10 can be used in a state where the press-fitting is completed (low bonding and spot welding are unnecessary). The order of fixing the cam pieces 12, 13 and the gear 14 to the cam shaft 11 is, in order from one end of the cam shaft 11, the rolling of the rolling projection 11a at the press-fitting position of the gear 14,
The operations of press-fitting the gear 14, rolling the position of the cam piece 13, pressing the cam piece 13, rolling the position of the cam piece 12, and press-fitting the cam piece 12 are alternately repeated in this order, and the camshaft 10 as shown in FIG. 1 is completed. . In the camshaft 10 having the above structure,
Since the cam pieces 11 and 12 and the gear 14 can be fixed to an arbitrary angular position of the camshaft 11 only by press-fitting the camshaft 11 into the camshaft 11, the assembling work is extremely easy and time-consuming, productivity is increased, and manufacturing cost is increased. The position is reduced, and high positional accuracy can be easily realized. Furthermore, since the torque load is distributed and handled as described above, the tightening force in the circumferential direction is not applied as much as the conventional press-fit camshaft, so a low cost and high dimensional accuracy sintered alloy cam piece is used. From this point, cost reduction and high accuracy can be achieved. As described above, for both the cam piece and the gear, the bonding strength is determined by the difference (hardness balance ΔH) between the hardness (Hk) of the inner diameter spline of the sintered molded part and the hardness (Hs) of the rolled portion of the shaft. The optimal value of the hardness balance is H
k = Hs + HRC (10 to 40), and the results of a press-fit repetitive load test using a test piece having a material hardness specified in the present invention are described below for reference. Test Piece Material, Heat Treatment, Hardness, Shaft Diameter, and Combination (1) Cam Shaft: S45C Standard Heat Treatment Hardness: HRB
90-98 (HRC11-20) Shaft diameter: 15mm Gear: JIS SMF 5 type induction hardening Hardness: HRC39-42 Joint width: 8mm Difference between gear inner diameter and camshaft rolled part outer shape (press-fitting allowance): 0.34 ~
0.42 (2) Cam shaft: S45C Standard heat treatment Hardness: HRB
90-98 (HRC11-20) Shaft diameter: 15mm Cam piece: JIS SMF type 8 carburized Hardness: HRC41-46 Joint width: 8mm Difference between cam piece and camshaft rolled part outer shape (press-fitting allowance): 0.34
~ 0.42 In the combination of the test piece (1),
The results of the fatigue test with a repeated torque load of 10 kg-m and the number of repetitions of 1 × 10 7 showed that the gear was cammed in a comparison between the test piece subjected to the fatigue test and the same test piece not subjected to the fatigue test. There was no difference in extraction load from the shaft, and it was determined that the press-fit combination camshaft had a firm connection with no loosening. In the combination of the test pieces (2), the bonding strength of the press-fit combination is the same as that of the case (1), but since the cam shape has a relatively thin annular portion, it is used as a sintered alloy part. Is a point at which the breakage due to the tension acting on the annular portion of the cam piece at the time of press fitting is a concern. However, as described above, since the hardness of the cam piece and gear material is kept close to HRC45, there is room for elongation, and the results of the actual machine durability test show that there is room for sufficient tension. did it. FIG. 5 shows the results of the fatigue test. From the figure, the hardness balance ΔH is ΔH = H
In the range of RC10 to RC40, it can be seen that there is no damage even in the repetitive load test at the limit number of repetitions of 10 < 7 >. According to the conventional method of creating meshing teeth in the circumferential direction of the shaft while press-fitting the cam part into the cam shaft, and applying the heat treatment hardness of the above-mentioned materials, the JIS SMF 5 or 8 sintering method can be used. Binder material can be used, and the press-fit connection strength is sufficient.The gap between the cam piece and the cam shaft is filled with a metal brazing agent, the connection between the cam piece and the cam shaft is increased by spot welding, It is not necessary to provide a slight taper, and by using a high-precision sintered body for the cam and gear, it is possible to manufacture a camshaft that can greatly reduce costs by eliminating machining after assembly. Become. As a material for the camshaft, carbon steel for machine structural use which is usually available, has good toughness, and is easy to handle.
G4051 S45C material can also be used, and the cost can be further reduced.
【図面の簡単な説明】
【図１】本発明の実施例のカムシャフトの側面断面図
【図２】図１のＡ部詳細図
【図３】図１のカムシャフトを右側から見た図
【図４】図３のＢ部詳細図
【図５】疲労試験の結果を示すグラフ。
【図６】従来のカムシャフトを示す断面図
【図７】図６のII−II断面図
【図８】従来のカムシャフトの製造工程を示す図２応当
図
【符号の説明】
１０…カムシャフト、１１…カム軸、１１ａ…転造突出
部、１２，１３…カムピース、１２ａ…スプライン、１
２ｂ…面取り部、１４…歯車。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of a camshaft according to an embodiment of the present invention. FIG. 2 is a detailed view of a portion A in FIG. 1. FIG. 3 is a view of the camshaft in FIG. FIG. 4 is a detailed view of a portion B in FIG. 3; FIG. 5 is a graph showing results of a fatigue test. 6 is a sectional view showing a conventional camshaft. FIG. 7 is a sectional view taken along the line II-II of FIG. 6. FIG. 8 is an equivalent view of FIG. 2 showing a manufacturing process of the conventional camshaft. , 11: cam shaft, 11a: rolling projection, 12, 13: cam piece, 12a: spline, 1
2b: chamfer, 14: gear.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 中村 彰吾 愛知県名古屋市中村区岩塚町字高道１番 地 三菱重工業株式会社名古屋機器製作 所内 (56)参考文献 特開 平６−264990（ＪＰ，Ａ) 特開 平５−187520（ＪＰ，Ａ) 特開 昭51−34318（ＪＰ，Ａ) 特開 平２−150544（ＪＰ，Ａ) 特開 平４−308305（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) F01L 1/04 F16H 53/02 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Shogo Nakamura Inventor, Nagoya Kiki Seisakusho, Mitsubishi Heavy Industries, Ltd. Nagoya Kiki Co., Ltd. A) JP-A-5-187520 (JP, A) JP-A-51-34318 (JP, A) JP-A-2-150544 (JP, A) JP-A-4-308305 (JP, A) (58) Survey Field (Int.Cl. 7 , DB name) F01L 1/04 F16H 53/02
Claims (1)
幅に亙って多数の円周方向の台形溝を転造した鋼材製の
カム軸に、内筒面に軸方向のスプラインを設けた前記カ
ムピース及び歯車を圧入結合して製造されるカムシャフ
トにおいて、転造部硬度（Ｈｓ）がＨＲＣ11〜20の鋼材製カム軸と、
これに圧入される前記カムピース及び歯車は焼結合金材
料とし、 前記圧入されるカムピース及び歯車を高周波焼入若しく
は浸炭焼き入れにより表面硬化を行い、表面硬化させた
内周面表面硬度（Ｈｋ）が カム軸の材料の硬度よりＨＲ
Ｃ10〜40大きい範囲の〔Ｈｋ＝Ｈｓ＋ＨＲＣ（10〜4
0）〕とし、前記カムピース及び歯車の前記スプライン
に施された面取り部側からのカム軸への圧入結合によ
り、前記カムピース及び歯車のスプライン端がカム軸の
転造膨出部を塑性変形及び剪断せしめてかみ合い歯を創
製するように構成されたことを特徴とする部品圧入カム
シャフト。(57) [Claims] 1. Press-fit into the mounting position of cam piece and gear
Rolled steel with a number of circumferential trapezoidal grooves over the width
The camshaft provided with an axial spline on the inner cylinder surface.
Cam shuffs manufactured by press-fitting an internal part and a gear
AtA steel camshaft having a rolled portion hardness (Hs) of HRC 11 to 20,
The cam piece and the gear to be pressed into this are made of a sintered alloy material.
Charge The cam pieces and gears to be press-fitted are induction hardened.
Was surface hardened by carburizing and quenching
Inner peripheral surface hardness (Hk) HR from camshaft material hardness
[Hk = Hs + HRC (10-4
0)] and the cam piece and the gearSaidspline
Press-fit connection to the camshaft from the chamfered side
The spline ends of the cam piece and the gear
The meshing teeth are created by plastically deforming and shearing the rolled bulge.
Parts press-fit cam characterized in that it is configured to be manufactured
shaft.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27032494A JP3408644B2 (en) | 1994-10-07 | 1994-10-07 | Parts press-fit camshaft |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27032494A JP3408644B2 (en) | 1994-10-07 | 1994-10-07 | Parts press-fit camshaft |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08105307A JPH08105307A (en) | 1996-04-23 |
| JP3408644B2 true JP3408644B2 (en) | 2003-05-19 |
Family
ID=17484685
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27032494A Expired - Fee Related JP3408644B2 (en) | 1994-10-07 | 1994-10-07 | Parts press-fit camshaft |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3408644B2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006169960A (en) * | 2003-12-12 | 2006-06-29 | Honda Motor Co Ltd | Camshaft |
| DE502004002527D1 (en) * | 2004-01-12 | 2007-02-15 | Robert Buergler | Arrangement and method for producing a camshaft |
| DE102004009074B3 (en) * | 2004-02-23 | 2005-07-07 | Thyssenkrupp Automotive Ag | Compound cam for camshaft for automobile engine assembled from 2 individual cam parts coupled together via intermediate ring |
| DE112006000244B4 (en) | 2005-01-19 | 2021-01-14 | Mitsuba Corp. | Gear wheel of a transmission and rolling molds for its manufacture |
| KR100682999B1 (en) * | 2005-07-08 | 2007-02-15 | 주식회사 에스 피 지 | Coupling structure of gear and spindle and coupling method |
| DE102009057633B3 (en) * | 2009-12-09 | 2011-03-31 | Thyssenkrupp Presta Teccenter Ag | Method of making a built camshaft, camshaft body and camshaft |
| DE102013005713A1 (en) | 2013-03-30 | 2014-10-02 | Thyssenkrupp Presta Teccenter Ag | Spannnest with fixing elements |
| DE102014106924A1 (en) * | 2014-05-16 | 2015-11-19 | Thyssenkrupp Presta Teccenter Ag | Method of making a built camshaft |
| CN108442990B (en) * | 2018-06-14 | 2024-02-13 | 成都金顶精密铸造有限公司 | Combined cam shaft |
-
1994
- 1994-10-07 JP JP27032494A patent/JP3408644B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08105307A (en) | 1996-04-23 |
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