JP4075676B2

JP4075676B2 - Telescopic shaft and manufacturing method thereof

Info

Publication number: JP4075676B2
Application number: JP2003124326A
Authority: JP
Inventors: 周三平櫛
Original assignee: JTEKT Corp
Current assignee: JTEKT Corp
Priority date: 2003-04-28
Filing date: 2003-04-28
Publication date: 2008-04-16
Anticipated expiration: 2023-04-28
Also published as: JP2004324863A

Description

【０００１】
【発明の属する技術分野】
本発明は、車両用操舵装置等に用いられる伸縮自在シャフトおよびその製造方法に関する。
【０００２】
【従来の技術】
伸縮自在シャフトとしては、インターミディエイトシャフト、テレスコピック調節可能なステアリングシャフト等があり、中空の外軸部と、これに嵌合される内軸部とを有し、両軸部をスプライン嵌合することにより軸方向に摺動自在としている。この種の伸縮自在シャフトでは、回転時や摺動時の両軸部のがたつきを抑えるために多くの提案がなされている。
【０００３】
例えば、外軸部の雌スプラインの全ての歯の圧力角を、標準的な値と異ならせたものがある（例えば、特許文献１参照）。
また、外軸部の雌スプラインの一部の歯の歯厚を、他の歯の歯厚と異ならせたものがある（例えば、特許文献２参照）。
【０００４】
【特許文献１】
特開平１１−２８０７７８号公報
【特許文献２】
特開平５−１４１４３２号公報
【０００５】
【発明が解決しようとする課題】
しかし、特許文献１および特許文献２の伸縮自在シャフトでは、スプラインの歯の加工が特殊になるので、加工コストが高い。
また、伸縮自在シャフトにがたつきが生じると、異音や振動が生じる。
そこで、本発明の目的は、上述の技術的課題を解決し、異音や振動の発生を抑制できて安価な伸縮自在シャフトおよびその製造方法を提供することである。
【０００６】
【課題を解決するための手段および発明の効果】
第１の発明の伸縮自在シャフトは、雌スプラインを軸方向に形成した外軸部の嵌合孔に、上記雌スプラインに係合する雄スプラインを軸方向に形成した内軸部を挿入してなる伸縮自在シャフトにおいて、上記外軸部は、中空部材からなり、上記中空部材の外周には、縮径部と、この縮径部を中空部材の軸方向の両側に挟む一対の太径部とが設けられ、上記中空部材の内周の部分であって縮径部と一対の太径部とに対応する部分に、上記雌スプラインが形成され、上記縮径部は周方向に連続しており、上記中空部材の肉厚に関して、縮径部と内周との間は相対的に薄肉に形成され、各太径部と内周との間は相対的に厚肉に形成されており、上記雌スプラインは、縮径部に対応する部分を含み、雌スプラインは、その縮径部に対応する部分における軸方向中央部において、中空部材の径方向内方に最も突出していることを特徴とする。この発明によれば、外周に縮径部が形成された中空部材では、縮径部に対応する薄肉部が形成されている。このような中空部材の内周に工具を通して雌スプラインを加工するときに、工具による加工圧力で上記薄肉部が拡径された状態で雌スプラインが形成され、加工後に、スプリングバックにより薄肉部が元の状態に収縮する。このため、縮径部に対応する雌スプラインの領域は残りの領域よりも径方向内方へ突出するので、両軸部の嵌合のがたを格段に少なくすることができる結果、振動や騒音を低減することができる。また、がたを少なくできる雌スプラインを、通常の加工方法で安価に形成できる。
【０００７】
第２の発明の伸縮自在シャフトは、雌スプラインを軸方向に形成した外軸部の嵌合孔に、上記雌スプラインに係合する雄スプラインを軸方向に形成した内軸部を挿入してなる伸縮自在シャフトにおいて、上記内軸部は、中空部材からなり、上記中空部材の内周には、拡径部と、この拡径部を中空部材の軸方向の両側に挟む一対の細径部とが設けられ、上記中空部材の外周の部分であって拡径部と一対の細径部とに対応する部分に、上記雄スプラインが形成され、上記拡径部は周方向に連続しており、上記中空部材の肉厚に関して、拡径部と外周との間は相対的に薄肉に形成され、各細径部と外周との間は相対的に厚肉に形成されており、上記雄スプラインは、拡径部に対応する部分を含み、雄スプラインは、その拡径部に対応する部分における軸方向中央部において、中空部材の径方向外方に最も突出していることを特徴とする。この発明によれば、内周に拡径部が形成された中空部材では、拡径部に対応する薄肉部が形成されている。このような中空部材の外周に雄スプラインを加工するときに、工具による加工圧力で薄肉部が縮径された状態で雄スプラインが形成され、加工後に、スプリングバックにより薄肉部が元の状態に拡径する。このため、拡径部に対応する雄スプラインの領域は残りの領域よりも径方向外方へ突出するので、両軸部の嵌合のがたを格段に少なくすることができる結果、振動や騒音を低減することができる。また、がたを少なくできる雄スプラインを、通常の加工方法で安価に形成できる。
【０００８】
第３の発明の伸縮自在シャフトは、雌スプラインを軸方向に形成した外軸部の嵌合孔に、上記雌スプラインに係合する雄スプラインを軸方向に形成した内軸部を挿入してなる伸縮自在シャフトにおいて、上記外軸部は、第１の中空部材からなり、上記第１の中空部材の外周には、縮径部と、この縮径部を第１の中空部材の軸方向の両側に挟む一対の太径部とが設けられ、上記第１の中空部材の内周の部分であって縮径部と一対の太径部とに対応する部分に、上記雌スプラインが形成され、上記縮径部は周方向に連続しており、上記第１の中空部材の肉厚に関して、縮径部と内周との間は相対的に薄肉に形成され、各太径部と内周との間は相対的に厚肉に形成されており、上記内軸部は、第２の中空部材からなり、上記第２の中空部材の内周には、拡径部と、この拡径部を第２の中空部材の軸方向の両側に挟む一対の細径部とが設けられ、上記第２の中空部材の外周の部分であって拡径部と一対の細径部とに対応する部分に、上記雄スプラインが形成され、上記拡径部は周方向に連続しており、上記第２の中空部材の肉厚に関して、拡径部と外周との間は相対的に薄肉に形成され、各細径部と外周との間は相対的に厚肉に形成されており、上記雌スプラインは、縮径部に対応する部分を含み、雌スプラインは、その縮径部に対応する部分における軸方向中央部において、第１の中空部材の径方向内方に最も突出しており、上記雄スプラインは、拡径部に対応する部分を含み、雄スプラインは、その拡径部に対応する部分における軸方向中央部において、第２の中空部材の径方向外方に最も突出していることを特徴とする。この発明によれば、第１および第２の発明の組合せにより、両軸部の嵌合のがたをより少なくでき、振動や騒音をより低減することができ、しかも、がたを少なくできて安価な伸縮自在シャフトを実現できる。
第４の発明の伸縮自在シャフトの製造方法は、雌スプラインを軸方向に形成した外軸部の嵌合孔に、上記雌スプラインに係合する雄スプラインを軸方向に形成した内軸部を挿入してなる伸縮自在シャフトにおいて、上記外軸部は、中空部材からなり、上記中空部材の外周には、縮径部と、この縮径部を中空部材の軸方向の両側に挟む一対の太径部とが設けられ、上記中空部材の内周の部分であって縮径部と一対の太径部とに対応する部分に、上記雌スプラインが形成され、上記縮径部は周方向に連続しており、上記中空部材の肉厚に関して、縮径部と内周との間は相対的に薄肉に形成され、各太径部と内周との間は相対的に厚肉に形成されている伸縮自在シャフトを製造する伸縮自在シャフトの製造方法であって、上記外軸部には、中空部材の外周に縮径部および一対の太径部が形成された後に、中空部材の内周に雌スプラインが形成されることを特徴とする。
第５の発明の伸縮自在シャフトの製造方法は、雌スプラインを軸方向に形成した外軸部の嵌合孔に、上記雌スプラインに係合する雄スプラインを軸方向に形成した内軸部を挿入してなる伸縮自在シャフトにおいて、上記内軸部は、中空部材からなり、上記中空部材の内周には、拡径部と、この拡径部を中空部材の軸方向の両側に挟む一対の細径部とが設けられ、上記中空部材の外周の部分であって拡径部と一対の細径部とに対応する部分に、上記雄スプラインが形成され、上記拡径部は周方向に連続しており、上記中空部材の肉厚に関して、拡径部と外周との間は相対的に薄肉に形成され、各細径部と外周との間は相対的に厚肉に形成されている伸縮自在シャフトを製造する伸縮自在シャフトの製造方法であって、上記内軸部には、中空部材の内周に拡径部および一対の細径部が形成された後に、中空部材の外周に雄スプラインが形成されることを特徴とする。
第６の発明の伸縮自在シャフトの製造方法は、雌スプラインを軸方向に形成した外軸部の嵌合孔に、上記雌スプラインに係合する雄スプラインを軸方向に形成した内軸部を挿入してなる伸縮自在シャフトにおいて、上記外軸部は、第１の中空部材からなり、上記第１の中空部材の外周には、縮径部と、この縮径部を第１の中空部材の軸方向の両側に挟む一対の太径部とが設けられ、上記第１の中空部材の内周の部分であって縮径部と一対の太径部とに対応する部分に、上記雌スプラインが形成され、上記縮径部は周方向に連続しており、上記第１の中空部材の肉厚に関して、縮径部と内周との間は相対的に薄肉に形成され、各太径部と内周との間は相対的に厚肉に形成されており、上記内軸部は、第２の中空部材からなり、上記第２の中空部材の内周には、拡径部と、この拡径部を第２の中空部材の軸方向の両側に挟む一対の細径部とが設けられ、上記第２の中空部材の外周の部分であって拡径部と一対の細径部とに対応する部分に、上記雄スプラインが形成され、上記拡径部は周方向に連続しており、上記第２の中空部材の肉厚に関して、拡径部と外周との間は相対的に薄肉に形成され、各細径部と外周との間は相対的に厚肉に形成されている伸縮自在シャフトを製造する伸縮自在シャフトの製造方法であって、上記外軸部には、第１の中空部材の外周に縮径部および一対の太径部が形成された後に、第１の中空部材の内周に雌スプラインが形成され、上記内軸部には、第２の中空部材の内周に拡径部および一対の細径部が形成された後に、第２の中空部材の外周に雄スプラインが形成されることを特徴とする。
第７の発明の伸縮自在シャフトの製造方法は、第１の発明の伸縮自在シャフトの製造方法であって、上記外軸部には、中空部材の外周に縮径部および一対の太径部が形成された後に、中空部材の内周に雌スプラインが形成されることを特徴とする。
第８の発明の伸縮自在シャフトの製造方法は、第２の発明の伸縮自在シャフトの製造方法であって、上記内軸部には、中空部材の内周に拡径部および一対の細径部が形成された後に、中空部材の外周に雄スプラインが形成されることを特徴とする。
第９の発明の伸縮自在シャフトの製造方法は、第３の発明の伸縮自在シャフトの製造方法であって、上記外軸部には、第１の中空部材の外周に縮径部および一対の太径部が形成された後に、第１の中空部材の内周に雌スプラインが形成され、上記内軸部には、第２の中空部材の内周に拡径部および一対の細径部が形成された後に、第２の中空部材の外周に雄スプラインが形成されることを特徴とする。
【０００９】
【発明の実施の形態】
本発明の第１の実施形態の伸縮自在シャフトとしての中間軸を説明する。図１は、上述の中間軸を設けた車両用操舵装置の概略構成を示す模式図である。
図１を参照して、車両用操舵装置１は中間軸２を有する。中間軸２は、インターミディエイトシャフトとも呼ばれて、車輪（図示せず）を操向するためにステアリングホイール３に加えられる操舵トルクを、一方の端部４ａにステアリングホイール３を連結されるステアリングシャフト４から、車輪を操向するための舵取り機構５へ伝達する。
【００１０】
車両用操舵装置１は、上述の操舵トルクを伝達するステアリングシャフト４と、このステアリングシャフト４を内部に通して回転自在に支持するステアリングコラム６とを有する。ステアリングシャフト４の他方の端部４ｂに、自在継手７、本中間軸２、自在継手８等を介して上述の舵取り機構５の回転軸９が連結される。ステアリングホイール３が操舵されると、その操舵トルクがステアリングシャフト４等を介して舵取り機構５に伝達され、これにより車輪を操向することができる。
【００１１】
ステアリングシャフト４は、一端にステアリングホイール３を連結する外軸部としてのアッパシャフト１０と、内軸部としてのロアシャフト１１とを有する。アッパシャフト１０とロアシャフト１１とは、ステアリングシャフト４の軸方向に沿って互いに相対移動自在に、且つ一体回転するように、スプライン嵌合構造により互いに連結されている。ステアリングシャフト４は、ステアリングホイール３の位置を調節するために、また、自動車の衝突時の衝撃を吸収するために、伸縮可能な伸縮自在シャフトとして機能する。
【００１２】
車両用操舵装置１では、ステアリングコラム６を位置調節可能に車体１２（一部のみ図示）に支持して、ステアリングホイール３の位置を調節できるようにされている。位置調節に伴いステアリングシャフト４の他方の端部４ｂの位置が変化することがある。また、走行時に舵取り機構５の位置が変化することがある。このような位置の変化を吸収できるように、中間軸２は伸縮自在とされる。
中間軸２は、中空の外軸部１３と、内軸部１４とを有し、外軸部１３の端部１３ａの嵌合孔１３ｂに、内軸部１４の端部１４ａを挿入してなる。両軸部１３，１４の軸線はともに中間軸２の軸線と一致する。両軸部１３，１４の対応する端部１３ａ，１４ａは、中間軸２の軸方向Ｓに相対摺動自在に互いにスプライン嵌合される。両軸部１３，１４は、鋼等の金属部材からなる。
【００１３】
図２および図３を参照する。外軸部１３の端部１３ａの嵌合孔１３ｂの内周１３ｃには、雌スプライン１５がその軸方向Ｓに延びて形成される。雌スプライン１５は、その軸方向Ｓに所定長さで延びる多数のスプライン歯を有する。外軸部１３の端部１３ａの外周１３ｄには、所定の幅を持つ小径の縮径部１３ｅと、この縮径部１３ｅをその軸方向Ｓに挟む一対の太径部１３ｆとを有する。縮径部１３ｅの径方向内方に薄肉部１３ｇが形成される。
【００１４】
内軸部１４は例えば、中空形状に形成される。内軸部１４の端部１４ａの外周１４ｂには、雌スプライン１５と係合する雄スプライン１６がその軸方向Ｓに延びて形成される。雄スプライン１６は、その軸方向Ｓに所定長さで延びる多数のスプライン歯を有する。雌スプライン１５の歯と雄スプライン１６の歯とは互いに噛み合わされる。両スプライン１５，１６の歯が縮径部１３ｅの径方向内方において常に噛み合うように、縮径部１３ｅは配置される。
【００１５】
本実施形態では、図４Ｂ，図４Ｅを参照して、外軸部１３は、外周１７ｄに縮径部１７ｅを設けた製造用中間体としての中空部材１７の内周１７ｃに雌スプライン１５を形成してなる。図４Ａを参照して、例えば、所定長のパイプ材１７ａに、内周１７ｃおよび外周１７ｄを加工し、この外周加工と同時に縮径部１７ｅを加工して、図４Ｂに示す上述の中空部材１７を得る。中空部材１７には、縮径部１７ｅに対応して薄肉部１７ｇが形成される。その後、中空部材１７の内周１７ｃに雌スプライン１５が例えばブローチ加工により形成されて、図４Ｅに示す外軸部１３を得る。図４Ｂおよび図４Ｅを参照して、中空部材１７の内周１７ｃ、外周１７ｄ、縮径部１７ｅおよび薄肉部１７ｇが、外軸部１３の対応する内周１３ｃ、外周１３ｄ、縮径部１３ｅおよび薄肉部１３ｇとなる。次に、外軸部１３に、予め形成された内軸部１４を嵌合して、中間軸２を得る。
【００１６】
このように本実施形態によれば、図４Ｂを参照して、外周１７ｄに縮径部１７ｅが形成された中空部材１７では、縮径部１７ｅに対応する薄肉部１７ｇが形成されている。このような中空部材１７の内周１７ｃに工具１８を通して雌スプライン１５を加工するときに、図４Ｃを参照して、工具１８による加工圧力で上記薄肉部１７ｇが径方向外方Ｒ１へ付勢されて拡径された状態で雌スプライン１５が形成され、加工後に、図４Ｄを参照して、スプリングバックにより薄肉部１７ｇが元の状態に収縮する。このため、軸方向Ｓについて、縮径部１７ｅに対応する雌スプライン１５の領域１５ａは残りの領域１５ｂよりも径方向内方Ｒ２へ突出する。例えば、領域１５ａの内周は、領域１５ｂの内周に比べて数μｍ小さく仕上がる。その結果、図４Ｅに示すように、両軸部１３，１４を組み合わせたときに、両軸部１３，１４のスプライン嵌合のがたを格段に少なくすることができる。従って、振動や騒音を低減することができる。
【００１７】
また、がたを少なくできる雌スプライン１５を、通常の加工方法で安価に形成できる。
また、図４Ｂを参照して、本中間軸２では、外軸部１３の製造用中間体としての中空部材１７に縮径部１７ｅを設けるようにした。これにより、がたつきを防止するための設計変更が僅かで済み、がたつきの防止をコスト上昇なしに実現できる。また、がたつきを防止するための従来のばね部材等を用いずに済ますこともできる。
【００１８】
また、図２を参照して、縮径部１３ｅに対応する薄肉部１３ｇは、中間軸２の径方向Ｒ１，Ｒ２に弾性変形して、内軸部１４を弾力的に付勢でき、吸振作用を発揮し、振動および異音の低減に効果的に寄与する。
本発明の第２の実施形態を説明する。以下では、上述の実施形態と異なる点を中心に説明し、同様の構成については説明を省略して同じ符号を付しておく。また、後述する他の実施形態や変形例についても同様にして説明する。
【００１９】
図５および図６を参照する。第２実施形態の中間軸２０１は、第１実施形態の外軸部１３に代えて外軸部１３１を有し、第１実施形態の内軸部１４に代えて内軸部１４１を有する。
外軸部１３１の端部１３ａは、外周１３ｄを軸方向について断面形状一定とし、外周１３ｄは上述の縮径部１３ｅを省略されている。雌スプライン１５は軸方向Ｓについて同等に形成される。
【００２０】
内軸部１４１は、その内周１４ｃに拡径部１４ｄと、拡径部１４ｄを軸方向に挟む一対の細径部１４ｆを設けられる。拡径部１４ｄに対応して、その径方向外方に、薄肉部１４ｅが形成される。
図７Ｂ，図７Ｅを参照して、内軸部１４１は、内周１９ｃに拡径部１９ｄを設けた製造用中間体としての中空部材１９の外周１９ｂに雄スプライン１６を形成してなる。図７Ａを参照して、例えば、所定長のパイプ材１９ａに、外周１９ｂおよび内周１９ｃを加工し、この内周加工と同時に拡径部１９ｄを加工して、図７Ｂに示す上述の中空部材１９を得る。中空部材１９には、拡径部１９ｄに対応して薄肉部１９ｅが形成される。その後、中空部材１９の外周１９ｂに雄スプライン１６が例えば歯切り切削加工により形成されて、図７Ｅに示す内軸部１４１を得る。図７Ｂ，図７Ｅを参照して、中空部材１９の外周１９ｂ、内周１９ｃ、拡径部１９ｄおよび薄肉部１９ｅが、内軸部１４１の対応する外周１４ｂ、内周１４ｃ、拡径部１４ｄおよび薄肉部１４ｅとなる。次に、予め形成された外軸部１３１に、上述のようにして形成された内軸部１４１を嵌合して、中間軸２０１を得る。
【００２１】
このように本発明の第２実施形態によれば、図７Ｂを参照して、内周１９ｃに拡径部１９ｄが形成された中空部材１９では、拡径部１９ｄに対応する薄肉部１９ｅが形成されている。このような中空部材１９の外周１９ｂに雄スプライン１６を加工するときに、図７Ｃを参照して、工具２０による加工圧力で薄肉部１９ｅが径方向内方Ｒ２へ付勢されて縮径された状態で雄スプライン１６が形成され、加工後に、図７Ｄを参照して、スプリングバックにより薄肉部１９ｅが元の状態に拡径する。このため、軸方向Ｓについて拡径部１９ｄに対応する雄スプライン１６の領域１６ａは、残りの領域１６ｂよりも径方向外方Ｒ１へ突出する。例えば、領域１６ａの外周は、領域１６ｂの外周に比べて数μｍ大きく仕上がる。その結果、両軸部１３１，１４１の嵌合のがたを格段に少なくすることができる結果、振動や騒音を低減することができる。
【００２２】
また、がたを少なくできる雄スプライン１６を、通常の加工方法で安価に形成できる。また、内軸部１４１は、第１の実施形態と同様に僅かの変更で、がたつきの防止をコスト上昇なしに実現できる。
また、図５を参照して、内軸部１４１の拡径部１４ｄに対応する薄肉部１４ｅは、内軸部１４１の径方向Ｒ１，Ｒ２に弾性変形して、外軸部１３１を弾力的に付勢でき、吸振作用を発揮し、振動および異音の低減に効果的に寄与する。
【００２３】
図８を参照する。第３実施形態の中間軸２０２は、第１実施形態の縮径部１３ｅを有する外軸部１３と、第２実施形態の拡径部１４ｄを有する内軸部１４１とを組み合わせてなる。内軸部１４１の拡径部１４ｄと、外軸部１３の縮径部１３ｅとは、軸方向Ｓについての位置をほぼ一致して配置され、両軸部１３，１４１の軸方向Ｓの相対移動を考慮しても、内軸部１４１の拡径部１４ｄと外軸部１３の縮径部１３ｅとの少なくとも一部同士が、径方向から見たときに常に重なりあうように配置される。
【００２４】
第３実施形態によれば、第１および第２実施形態の効果を同様に得られる。特に、第１および第２実施形態の組合せにより、両軸部１３，１４１の嵌合のがたをより少なくでき、振動や騒音をより低減することができる。しかも、がたを少なくできて安価な伸縮自在シャフトとしての中間軸２０２を実現できる。
図９Ａ，図９Ｂ，図９Ｃを参照する。第４実施形態では、第３実施形態において、内軸部１４１に代えて、外周１９ｂの一部に樹脂コーティング膜２１を形成した中空部材１９１の外周１９ｂに雄スプライン１６を形成してなる内軸部１４２を用いる。中空部材１９１は、外周１９ｂに樹脂コーティング膜２１を形成されている点で、中空部材１９と異なる。樹脂コーティング膜２１は、周方向に延びる帯状に形成され、軸方向位置が拡径部１９ｄとほぼ一致する。
【００２５】
スプライン加工時に、樹脂コーティング膜２１を介在させることにより、工具２０から中空部材１９１が受ける加工圧力が高まり、中空部材１９１の薄肉部１９ｅの縮径量が大きくなる。スプライン加工後に、スプリングバックにより薄肉部１９ｅが元の状態に収縮した状態では、樹脂コーティング膜２１および拡径部１４ｄに対応する雄スプライン１６の領域１６ｃは残りの領域１６ｂよりも径方向外方Ｒ１へ突出し、この突出量が、中空部材１９を用いる場合に比べて大きくなる。樹脂コーティング膜２１は、スプライン加工時に除去されてもよいが、スプライン加工後に樹脂コーティング膜２１の一部が残る場合には、残ることになる樹脂コーティング膜２１の一部が、加工時に工具２０と中空部材１９１の表面との間で圧縮され、加工後に元に戻り、径方向外方Ｒ１へ突出する。
【００２６】
本実施の形態では、第３実施形態の効果に加えて、樹脂コーティング膜２１を設けることによるがた取り効果を得られ、両軸部１３，１４２のスプライン嵌合のがたを格段に少なくできる結果、振動や騒音を低減することができる。
また、本発明の各実施形態について、以下の変形例を考えることができる。
例えば、図２に示す内軸部１４は中実形状をなしてもよい。図８を参照して、拡径部１４ｄと縮径部１３ｅとを、軸方向Ｓについて常に互いに離間して配置してもよい。複数の縮径部１３ｅを軸方向Ｓに離間して設けても良い。複数の拡径部１４ｄを軸方向に離間して設けても良い。縮径部１３ｅを軸方向Ｓに開放するように軸端に配置してもよい。拡径部１４ｄを軸方向Ｓに開放するように軸端に配置してもよい。
【００２７】
図９Ｂ、図９Ｃを参照して、内軸部１４２の変形例として、中間部材１９１の拡径部１９ｄを省略したものも考えられる。この場合にも、樹脂コーティング膜２１によるがた取り効果を得ることができる。また、内軸部１４２やその変形例を、第２の実施形態において内軸部１４１に代えて用いても良い。
また、第１、第３および第４の実施形態の外軸部１３に、上述の樹脂コーティング膜２１によるがたどり方法を適用し、図４Ｂを参照して、外軸部１３が、内周１７ｃに樹脂コーティング膜２１（図９Ａ参照）を形成した中空部材１７の内周１７ｃに雌スプライン１５を形成してなる、ようにしてもよい。この場合にも、上述したようにがたどりの効果を得ることができる。樹脂コーティング膜２１は、縮径部１７ｅと軸方向位置を一致させるのが、がた取り効果を得るためには好ましいが、縮径部１７ｅを省略することも考えられる。
【００２８】
雌スプラインの加工方法としては、転造加工、歯切り切削加工、ブローチ加工等を利用できる。雄スプラインの加工方法としては、転造加工、歯切り切削加工等を利用できる。また、樹脂コーティング膜２１を形成する場合のスプラインの加工方法には、歯切り切削加工、ブローチ加工等の切削による形成方法が好ましい。
また、本発明の各実施形態を、図１を参照して、伸縮自在シャフトとしてのステアリングシャフト４に適用し、ステアリングシャフト４を上述の各実施形態の中間軸２，２０１，２０２と同様に構成してもよく、この場合、アッパシャフト１０を内軸部とし、ロアシャフト１１を外軸部としてもよい。その他、本発明の特許請求の範囲で種々の変更を施すことが可能である。
【図面の簡単な説明】
【図１】本発明の第１実施形態の伸縮自在シャフトとしての中間軸を含む車両用操舵装置の概略構成を示す模式図である。
【図２】図１の中間軸の要部の断面図である。
【図３】図２に示す中間軸の要部の分解斜視図である。
【図４】図２に示す中間軸の外軸部の加工手順を示す模式図であり、加工順序に従って図４Ａ，図４Ｂ，図４Ｃ，図４Ｄおよび図４Ｅの順に示し、図４Ｃ，図４Ｄはスプラインの形成途中の状態を拡大して示している。
【図５】本発明の第２実施形態の中間軸の要部の断面図である。
【図６】図５に示す中間軸の要部の分解斜視図である。
【図７】図５に示す中間軸の内軸部の加工手順を示す模式図であり、加工順序に従って、図７Ａ，図７Ｂ，図７Ｃ，図７Ｄおよび図７Ｅの順に示し、図７Ｃ，図７Ｄはスプラインの形成途中の状態を拡大して示している。
【図８】本発明の第３実施形態の中間軸の要部の断面図である。
【図９】本発明の第４実施形態の内軸部の加工手順を示す模式図であり、加工順序に従って、図９Ａ，図９Ｂおよび図９Ｃの順に示す。
【符号の説明】
２，２０１，２０２中間軸（伸縮自在シャフト）
４ステアリングシャフト（伸縮自在シャフト）
１０アッパシャフト（外軸部）
１１ロアシャフト（内軸部）
１３，１３１外軸部
１３ｂ外軸部の嵌合孔
１３ｅ縮径部
１４，１４１，１４２内軸部
１４ｄ拡径部
１５雌スプライン
１６雄スプライン
１７，１９，１９１中空部材
１７ｃ，１９ｃ中空部材の内周
１７ｄ，１９ｂ中空部材の外周
１７ｅ中空部材の縮径部
１９ｄ中空部材の拡径部
Ｓ軸方向[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a telescopic shaft used for a vehicle steering device and the like, and a method for manufacturing the same .
[0002]
[Prior art]
The telescopic shaft includes an intermediate shaft, a telescopic adjustable steering shaft, etc., and has a hollow outer shaft portion and an inner shaft portion fitted to the hollow shaft portion, and both shaft portions are spline-fitted. This makes it slidable in the axial direction. In this type of telescopic shaft, many proposals have been made in order to suppress rattling of both shafts during rotation and sliding.
[0003]
For example, there is one in which the pressure angles of all teeth of the female spline of the outer shaft portion are different from standard values (for example, see Patent Document 1).
In addition, there is one in which the tooth thickness of some teeth of the female spline of the outer shaft portion is different from the tooth thickness of other teeth (for example, see Patent Document 2).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-280778 [Patent Document 2]
Japanese Patent Laid-Open No. 5-141432
[Problems to be solved by the invention]
However, in the telescopic shafts of Patent Document 1 and Patent Document 2, since the processing of spline teeth is special, the processing cost is high.
Further, when rattling occurs on the telescopic shaft, abnormal noise and vibration are generated.
Accordingly, an object of the present invention is to solve the above-described technical problems, and to provide an inexpensive telescopic shaft that can suppress the occurrence of abnormal noise and vibration and a method for manufacturing the same.
[0006]
[Means for Solving the Problems and Effects of the Invention]
The telescopic shaft of the first invention is formed by inserting an inner shaft portion in which a male spline that engages with the female spline is formed in the axial direction into a fitting hole of an outer shaft portion in which the female spline is formed in the axial direction. In the telescopic shaft, the outer shaft portion is made of a hollow member, and on the outer periphery of the hollow member, there is a reduced diameter portion and a pair of large diameter portions sandwiching the reduced diameter portion on both sides in the axial direction of the hollow member. The female spline is formed in a portion corresponding to the reduced diameter portion and the pair of large diameter portions, the inner peripheral portion of the hollow member, and the reduced diameter portion is continuous in the circumferential direction, regard the wall thickness of the hollow member, it is between the inner periphery and the reduced diameter portion is formed in a relatively thin, between the inner and KakuFutoshi diameter is formed in a relatively thick, the female The spline includes a portion corresponding to the reduced diameter portion, and the female spline is disposed in the portion corresponding to the reduced diameter portion. In the axial center portion, characterized in that the most projecting radially inwardly of the hollow member. According to this invention, in the hollow member in which the reduced diameter portion is formed on the outer periphery, the thin portion corresponding to the reduced diameter portion is formed. When processing a female spline through a tool on the inner periphery of such a hollow member, the female spline is formed in a state in which the thin-walled portion is expanded by the processing pressure of the tool, and after processing, the thin-walled portion is restored by a springback. Shrink to the state. For this reason, the region of the female spline corresponding to the reduced diameter portion protrudes inward in the radial direction as compared with the remaining region, so that the backlash of both shaft portions can be remarkably reduced, resulting in vibration and noise. Can be reduced. Moreover, the female spline which can reduce rattle can be formed at a low cost by a normal processing method.
[0007]
The telescopic shaft of the second invention is formed by inserting an inner shaft portion in which a male spline engaging with the female spline is formed in the axial direction into a fitting hole of an outer shaft portion in which the female spline is formed in the axial direction. In the telescopic shaft, the inner shaft portion is made of a hollow member, and on the inner periphery of the hollow member, there is an enlarged diameter portion, and a pair of small diameter portions sandwiching the enlarged diameter portion on both sides in the axial direction of the hollow member. The male spline is formed on the outer peripheral portion of the hollow member corresponding to the enlarged diameter portion and the pair of narrow diameter portions, and the enlarged diameter portion is continuous in the circumferential direction, regard the wall thickness of the hollow member, it is between the enlarged diameter portion and the outer peripheral formed relatively thin, between each small diameter portion and the outer circumference is formed relatively thick, the male spline Including a portion corresponding to the enlarged diameter portion, and the male spline is located in the portion corresponding to the enlarged diameter portion. In the axial center portion, characterized in that the most projecting radially outwardly of the hollow member. According to this invention, in the hollow member in which the enlarged diameter portion is formed on the inner periphery, the thin portion corresponding to the enlarged diameter portion is formed. When processing the male spline on the outer periphery of such a hollow member, the male spline is formed in a state where the thin-walled portion is reduced in diameter by the processing pressure of the tool, and after processing, the thin-walled portion is expanded to the original state by the spring back. Diameter. For this reason, the male spline region corresponding to the enlarged diameter portion protrudes radially outward from the remaining region, so that the backlash of both shaft portions can be remarkably reduced, resulting in vibration and noise. Can be reduced. Further, a male spline capable of reducing rattling can be formed at a low cost by a normal processing method.
[0008]
The telescopic shaft of the third invention is formed by inserting an inner shaft portion in which a male spline that engages with the female spline is formed in the axial direction into a fitting hole of an outer shaft portion in which the female spline is formed in the axial direction. In the telescopic shaft, the outer shaft portion is composed of a first hollow member, and a reduced diameter portion is provided on the outer periphery of the first hollow member, and the reduced diameter portion is disposed on both sides in the axial direction of the first hollow member. A pair of large-diameter portions sandwiched between the female splines, the inner hollow portion of the first hollow member corresponding to the reduced-diameter portion and the pair of large-diameter portions, The reduced diameter portion is continuous in the circumferential direction, and the thickness of the first hollow member is formed relatively thin between the reduced diameter portion and the inner periphery. The inner space is formed with a relatively thick wall, and the inner shaft portion is composed of a second hollow member, and is formed on the inner periphery of the second hollow member. An enlarged diameter portion and a pair of narrow diameter portions sandwiching the enlarged diameter portion on both sides in the axial direction of the second hollow member, the outer diameter portion of the second hollow member, The male spline is formed in a portion corresponding to the pair of small diameter portions, the large diameter portion is continuous in the circumferential direction, and the thickness of the second hollow member is between the large diameter portion and the outer periphery. The space between each thin diameter portion and the outer periphery is formed relatively thick, and the female spline includes a portion corresponding to the reduced diameter portion. In the central portion in the axial direction in the portion corresponding to the reduced diameter portion, it protrudes most inward in the radial direction of the first hollow member, and the male spline includes a portion corresponding to the enlarged diameter portion, In the axially central portion of the portion corresponding to the enlarged diameter portion, radially outward of the second hollow member Wherein the even projects. According to this invention, the combination of the first and second inventions can reduce the fit between both shaft portions, reduce vibration and noise, and reduce rattling. An inexpensive telescopic shaft can be realized.
According to a fourth aspect of the present invention, there is provided a method for manufacturing a telescopic shaft , wherein an inner shaft portion in which a male spline engaging with the female spline is formed in an axial direction is inserted into a fitting hole of an outer shaft portion in which a female spline is formed in an axial direction. In the retractable shaft, the outer shaft portion is made of a hollow member, and on the outer periphery of the hollow member, a reduced diameter portion and a pair of large diameters sandwiching the reduced diameter portion on both sides in the axial direction of the hollow member. The female spline is formed in a portion corresponding to the reduced diameter portion and the pair of large diameter portions, and the reduced diameter portion is continuous in the circumferential direction. The thickness of the hollow member is relatively thin between the reduced diameter portion and the inner periphery, and relatively thick between each large diameter portion and the inner periphery. A telescopic shaft manufacturing method for manufacturing a telescopic shaft, wherein the outer shaft portion includes a hollow member. After the reduced diameter portion and a pair of large-diameter portion is formed on the outer circumference, wherein the female spline on the inner periphery of the hollow member is formed.
According to a fifth aspect of the present invention, there is provided a method for manufacturing a telescopic shaft , wherein an inner shaft portion in which a male spline engaging with the female spline is formed in an axial direction is inserted into a fitting hole of an outer shaft portion in which a female spline is formed in an axial direction. In the retractable shaft, the inner shaft portion is made of a hollow member, and on the inner periphery of the hollow member, there is a diameter-enlarged portion and a pair of thin portions sandwiching the diameter-enlarged portion on both sides in the axial direction of the hollow member. The male spline is formed in a portion corresponding to the enlarged diameter portion and the pair of narrow diameter portions, and the enlarged diameter portion is continuous in the circumferential direction. The thickness of the hollow member is relatively thin between the enlarged diameter portion and the outer periphery, and is relatively stretchable between each small diameter portion and the outer periphery. A method of manufacturing a telescopic shaft for manufacturing a shaft, wherein the inner shaft portion includes a hollow member After the enlarged diameter portion and a pair of small diameter portions on the inner periphery are formed, characterized in that the male spline on the outer periphery of the hollow member is formed.
According to a sixth aspect of the present invention, there is provided a method for manufacturing the telescopic shaft , wherein an inner shaft portion in which a male spline that engages with the female spline is formed in an axial direction is inserted into a fitting hole in an outer shaft portion in which the female spline is formed in an axial direction. In the retractable shaft, the outer shaft portion is formed of a first hollow member, and a reduced diameter portion is provided on the outer periphery of the first hollow member, and the reduced diameter portion is provided on the shaft of the first hollow member. A pair of large diameter portions sandwiched between both sides in the direction, and the female spline is formed in a portion corresponding to the reduced diameter portion and the pair of large diameter portions on the inner periphery of the first hollow member The reduced diameter portion is continuous in the circumferential direction, and the thickness of the first hollow member is relatively thin between the reduced diameter portion and the inner periphery, and The inner shaft portion is formed of a second hollow member, and the second hollow portion is formed relatively thick between the circumference and the circumference. The inner periphery is of a diameter portion, and a pair of small diameter portions sandwiching the enlarged diameter portion on both sides in the axial direction of the second hollow member is provided, there in the outer peripheral portion of the second hollow member The male spline is formed in a portion corresponding to the enlarged diameter portion and the pair of narrow diameter portions, the enlarged diameter portion is continuous in the circumferential direction, and the diameter of the second hollow member is increased in diameter. A telescopic shaft manufacturing method for manufacturing a telescopic shaft that is formed relatively thin between a portion and an outer periphery, and is formed relatively thick between each small-diameter portion and the outer periphery. The outer shaft portion is formed with a reduced diameter portion and a pair of large diameter portions on the outer periphery of the first hollow member, and then a female spline is formed on the inner periphery of the first hollow member. The male spline is formed on the outer periphery of the second hollow member after the enlarged diameter portion and the pair of small diameter portions are formed on the inner periphery of the second hollow member. Characterized in that it is formed.
A method for manufacturing a telescopic shaft according to a seventh aspect is the method for manufacturing a telescopic shaft according to the first aspect, wherein the outer shaft portion has a reduced diameter portion and a pair of large diameter portions on the outer periphery of the hollow member. A female spline is formed on the inner periphery of the hollow member after being formed.
A method for manufacturing a telescopic shaft according to an eighth aspect of the present invention is the method for manufacturing a telescopic shaft according to the second aspect, wherein the inner shaft portion has an enlarged diameter portion and a pair of small diameter portions on the inner periphery of the hollow member. After the formation, the male spline is formed on the outer periphery of the hollow member.
A method for manufacturing a telescopic shaft according to a ninth aspect is the method for manufacturing a telescopic shaft according to the third aspect, wherein the outer shaft portion includes a reduced diameter portion and a pair of thicker portions on the outer periphery of the first hollow member. After the diameter portion is formed, a female spline is formed on the inner periphery of the first hollow member, and the inner shaft portion is formed with an enlarged diameter portion and a pair of small diameter portions on the inner periphery of the second hollow member. Then, a male spline is formed on the outer periphery of the second hollow member.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An intermediate shaft as a telescopic shaft according to the first embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle steering apparatus provided with the above-described intermediate shaft.
Referring to FIG. 1, a vehicle steering apparatus 1 has an intermediate shaft 2. The intermediate shaft 2 is also called an intermediate shaft, and a steering torque applied to the steering wheel 3 to steer a wheel (not shown), and a steering shaft connected to the steering wheel 3 at one end 4a. 4 to the steering mechanism 5 for steering the wheels.
[0010]
The vehicle steering apparatus 1 includes a steering shaft 4 that transmits the above-described steering torque, and a steering column 6 that rotatably supports the steering shaft 4 through the inside. The rotating shaft 9 of the steering mechanism 5 described above is connected to the other end 4b of the steering shaft 4 via the universal joint 7, the intermediate shaft 2, the universal joint 8, and the like. When the steering wheel 3 is steered, the steering torque is transmitted to the steering mechanism 5 via the steering shaft 4 or the like, and thereby the wheel can be steered.
[0011]
The steering shaft 4 has an upper shaft 10 as an outer shaft portion connecting the steering wheel 3 at one end, and a lower shaft 11 as an inner shaft portion. The upper shaft 10 and the lower shaft 11 are connected to each other by a spline fitting structure so that they can move relative to each other along the axial direction of the steering shaft 4 and rotate together. The steering shaft 4 functions as a telescopic shaft that can be expanded and contracted in order to adjust the position of the steering wheel 3 and to absorb an impact at the time of a car collision.
[0012]
In the vehicle steering apparatus 1, the steering column 6 is supported on a vehicle body 12 (only a part of which is shown) so that the position of the steering column 6 can be adjusted, and the position of the steering wheel 3 can be adjusted. As the position is adjusted, the position of the other end 4b of the steering shaft 4 may change. Further, the position of the steering mechanism 5 may change during traveling. The intermediate shaft 2 can be expanded and contracted so as to absorb such a change in position.
The intermediate shaft 2 has a hollow outer shaft portion 13 and an inner shaft portion 14, and the end portion 14 a of the inner shaft portion 14 is inserted into the fitting hole 13 b of the end portion 13 a of the outer shaft portion 13. . The axes of both the shaft portions 13 and 14 coincide with the axis of the intermediate shaft 2. The corresponding end portions 13a and 14a of the shaft portions 13 and 14 are spline-fitted to each other so as to be relatively slidable in the axial direction S of the intermediate shaft 2. Both shaft parts 13 and 14 consist of metal members, such as steel.
[0013]
Please refer to FIG. 2 and FIG. A female spline 15 is formed to extend in the axial direction S on the inner periphery 13 c of the fitting hole 13 b of the end 13 a of the outer shaft portion 13. The female spline 15 has a large number of spline teeth extending in a predetermined length in the axial direction S thereof. The outer periphery 13d of the end portion 13a of the outer shaft portion 13 has a small-diameter reduced diameter portion 13e having a predetermined width and a pair of large-diameter portions 13f sandwiching the reduced diameter portion 13e in the axial direction S. A thin portion 13g is formed on the radially inner side of the reduced diameter portion 13e.
[0014]
The inner shaft portion 14 is formed in a hollow shape, for example. On the outer periphery 14b of the end portion 14a of the inner shaft portion 14, a male spline 16 that engages with the female spline 15 is formed extending in the axial direction S. The male spline 16 has a large number of spline teeth extending in a predetermined length in the axial direction S thereof. The teeth of the female spline 15 and the teeth of the male spline 16 are meshed with each other. The reduced diameter portion 13e is arranged so that the teeth of both the splines 15 and 16 always mesh with each other inward in the radial direction of the reduced diameter portion 13e.
[0015]
In this embodiment, with reference to FIG. 4B and FIG. 4E, the outer shaft part 13 forms the female spline 15 in the inner periphery 17c of the hollow member 17 as a manufacturing intermediate body which provided the reduced diameter part 17e in the outer periphery 17d. Do it. Referring to FIG. 4A, for example, an inner periphery 17c and an outer periphery 17d are processed into a pipe material 17a having a predetermined length, and the reduced diameter portion 17e is processed simultaneously with the outer periphery processing. Get. The hollow member 17 has a thin portion 17g corresponding to the reduced diameter portion 17e. Thereafter, the female spline 15 is formed on the inner periphery 17c of the hollow member 17 by broaching, for example, to obtain the outer shaft portion 13 shown in FIG. 4E. 4B and 4E, the inner periphery 17c, outer periphery 17d, reduced diameter portion 17e and thinned portion 17g of the hollow member 17 correspond to the corresponding inner periphery 13c, outer periphery 13d, reduced diameter portion 13e and the outer shaft portion 13. The thin portion is 13 g. Next, the inner shaft 14 formed in advance is fitted to the outer shaft 13 to obtain the intermediate shaft 2.
[0016]
Thus, according to this embodiment, with reference to FIG. 4B, in the hollow member 17 in which the reduced diameter part 17e was formed in the outer periphery 17d, the thin part 17g corresponding to the reduced diameter part 17e is formed. When the female spline 15 is processed through the inner periphery 17c of the hollow member 17 through the tool 18, the thin-walled portion 17g is urged radially outward R1 by the processing pressure of the tool 18 with reference to FIG. 4C. The female spline 15 is formed in a state of being expanded in diameter, and after processing, with reference to FIG. 4D, the thin portion 17g is contracted to the original state by the spring back. For this reason, in the axial direction S, the region 15a of the female spline 15 corresponding to the reduced diameter portion 17e protrudes radially inward R2 from the remaining region 15b. For example, the inner periphery of the region 15a is finished several μm smaller than the inner periphery of the region 15b. As a result, as shown in FIG. 4E, when the shaft portions 13 and 14 are combined, the play of the spline fitting between the shaft portions 13 and 14 can be remarkably reduced. Therefore, vibration and noise can be reduced.
[0017]
Moreover, the female spline 15 that can reduce rattling can be formed at a low cost by a normal processing method.
4B, in the present intermediate shaft 2, the reduced diameter portion 17e is provided in the hollow member 17 as an intermediate for manufacturing the outer shaft portion 13. Thereby, the design change for preventing rattling is slight, and rattling can be prevented without increasing the cost. Further, it is possible to dispense with the use of a conventional spring member or the like for preventing rattling.
[0018]
Further, referring to FIG. 2, the thin wall portion 13g corresponding to the reduced diameter portion 13e is elastically deformed in the radial directions R1 and R2 of the intermediate shaft 2 and can elastically urge the inner shaft portion 14 to absorb vibration. To effectively reduce vibration and noise.
A second embodiment of the present invention will be described. Below, it demonstrates centering around a different point from the above-mentioned embodiment, description is abbreviate | omitted about the same structure, and the same code | symbol is attached | subjected. Also, other embodiments and modifications described later will be described in the same manner.
[0019]
Please refer to FIG. 5 and FIG. The intermediate shaft 201 of the second embodiment has an outer shaft portion 131 instead of the outer shaft portion 13 of the first embodiment, and has an inner shaft portion 141 instead of the inner shaft portion 14 of the first embodiment.
The end portion 13a of the outer shaft portion 131 has an outer periphery 13d having a constant cross-sectional shape in the axial direction, and the outer diameter 13d is omitted from the reduced diameter portion 13e. The female splines 15 are equally formed in the axial direction S.
[0020]
The inner shaft portion 141 is provided with an enlarged diameter portion 14d and a pair of small diameter portions 14f sandwiching the enlarged diameter portion 14d in the axial direction on the inner periphery 14c. Corresponding to the enlarged diameter portion 14d, a thin portion 14e is formed outward in the radial direction.
With reference to FIGS. 7B and 7E, the inner shaft portion 141 is formed by forming a male spline 16 on the outer periphery 19b of the hollow member 19 as a manufacturing intermediate body provided with the enlarged diameter portion 19d on the inner periphery 19c. Referring to FIG. 7A, for example, an outer periphery 19b and an inner periphery 19c are processed into a pipe material 19a having a predetermined length, and the enlarged diameter portion 19d is processed at the same time as the inner periphery processing. Get 19. A thin portion 19e is formed in the hollow member 19 corresponding to the enlarged diameter portion 19d. Thereafter, the male spline 16 is formed on the outer periphery 19b of the hollow member 19 by gear cutting, for example, to obtain an inner shaft portion 141 shown in FIG. 7E. 7B and 7E, the outer periphery 19b, the inner periphery 19c, the enlarged diameter portion 19d and the thinned portion 19e of the hollow member 19 correspond to the outer periphery 14b, the inner periphery 14c, the enlarged diameter portion 14d and the corresponding inner shaft portion 141, respectively. The thin portion 14e is formed. Next, the intermediate shaft 201 is obtained by fitting the inner shaft portion 141 formed as described above to the outer shaft portion 131 formed in advance.
[0021]
As described above, according to the second embodiment of the present invention, with reference to FIG. 7B, in the hollow member 19 in which the enlarged diameter portion 19d is formed on the inner periphery 19c, the thin portion 19e corresponding to the enlarged diameter portion 19d is formed. Has been. When processing the male spline 16 on the outer periphery 19b of such a hollow member 19, with reference to FIG. 7C, the thin wall portion 19e was urged radially inward R2 by the processing pressure by the tool 20 to reduce the diameter. The male spline 16 is formed in the state, and after processing, with reference to FIG. 7D, the thin wall portion 19e is expanded to the original state by the spring back. For this reason, the region 16a of the male spline 16 corresponding to the enlarged diameter portion 19d in the axial direction S protrudes radially outward R1 from the remaining region 16b. For example, the outer periphery of the region 16a is finished several μm larger than the outer periphery of the region 16b. As a result, the backlash of both shaft portions 131 and 141 can be remarkably reduced, so that vibration and noise can be reduced.
[0022]
Further, the male spline 16 that can reduce backlash can be formed at a low cost by a normal processing method. In addition, the inner shaft portion 141 can be prevented from rattling without a cost increase with a slight change as in the first embodiment.
Referring to FIG. 5, the thin portion 14e corresponding to the enlarged diameter portion 14d of the inner shaft portion 141 is elastically deformed in the radial directions R1 and R2 of the inner shaft portion 141, and the outer shaft portion 131 is elastically deformed. It can be energized, exhibits a vibration absorbing effect, and contributes effectively to the reduction of vibration and noise.
[0023]
Please refer to FIG. The intermediate shaft 202 of the third embodiment is a combination of the outer shaft portion 13 having the reduced diameter portion 13e of the first embodiment and the inner shaft portion 141 having the enlarged diameter portion 14d of the second embodiment. The enlarged diameter portion 14d of the inner shaft portion 141 and the reduced diameter portion 13e of the outer shaft portion 13 are arranged so that the positions in the axial direction S substantially coincide with each other, and the relative movement in the axial direction S of both the shaft portions 13 and 141 is performed. In consideration of this, at least a part of the enlarged diameter portion 14d of the inner shaft portion 141 and the reduced diameter portion 13e of the outer shaft portion 13 are arranged so as to always overlap each other when viewed from the radial direction.
[0024]
According to the third embodiment, the effects of the first and second embodiments can be obtained similarly. In particular, the combination of the first and second embodiments can reduce the amount of fitting between the shaft portions 13 and 141, and can further reduce vibration and noise. In addition, the intermediate shaft 202 can be realized as an inexpensive telescopic shaft with less backlash.
Reference is made to FIGS. 9A, 9B, and 9C. In the fourth embodiment, in place of the inner shaft portion 141 in the third embodiment, an inner shaft formed by forming the male spline 16 on the outer periphery 19b of the hollow member 191 in which the resin coating film 21 is formed on a part of the outer periphery 19b. Part 142 is used. The hollow member 191 is different from the hollow member 19 in that a resin coating film 21 is formed on the outer periphery 19b. The resin coating film 21 is formed in a belt shape extending in the circumferential direction, and its axial position substantially coincides with the enlarged diameter portion 19d.
[0025]
By interposing the resin coating film 21 at the time of spline processing, the processing pressure received by the hollow member 191 from the tool 20 increases, and the diameter reduction amount of the thin portion 19e of the hollow member 191 increases. After the spline processing, in a state where the thin portion 19e is contracted to the original state by the spring back, the region 16c of the male spline 16 corresponding to the resin coating film 21 and the enlarged diameter portion 14d is radially outward R1 from the remaining region 16b. The amount of protrusion is larger than when the hollow member 19 is used. The resin coating film 21 may be removed at the time of spline processing. However, when a part of the resin coating film 21 remains after the spline processing, a part of the resin coating film 21 that remains will be removed from the tool 20 at the time of processing. Compressed between the surfaces of the hollow member 191, returns to the original after processing, and protrudes radially outward R <b> 1.
[0026]
In the present embodiment, in addition to the effects of the third embodiment, a shading effect by providing the resin coating film 21 can be obtained, and the spline fitting of both shaft portions 13 and 142 can be remarkably reduced. As a result, vibration and noise can be reduced.
Moreover, the following modifications can be considered about each embodiment of this invention.
For example, the inner shaft portion 14 shown in FIG. 2 may have a solid shape. With reference to FIG. 8, the enlarged diameter portion 14 d and the reduced diameter portion 13 e may always be arranged apart from each other in the axial direction S. A plurality of reduced diameter portions 13e may be provided apart in the axial direction S. A plurality of enlarged diameter portions 14d may be provided apart in the axial direction. The reduced diameter portion 13e may be disposed at the shaft end so as to open in the axial direction S. The enlarged diameter portion 14d may be disposed at the shaft end so as to open in the axial direction S.
[0027]
With reference to FIG. 9B and FIG. 9C, as a modified example of the inner shaft portion 142, a configuration in which the enlarged diameter portion 19d of the intermediate member 191 is omitted can be considered. Also in this case, the effect of removing the resin coating film 21 can be obtained. Further, the inner shaft portion 142 and its modification may be used in place of the inner shaft portion 141 in the second embodiment.
Further, the above-described resin coating film 21 tracing method is applied to the outer shaft portion 13 of the first, third, and fourth embodiments, and referring to FIG. 4B, the outer shaft portion 13 has an inner circumference 17c. A female spline 15 may be formed on the inner periphery 17c of the hollow member 17 on which the resin coating film 21 (see FIG. 9A) is formed. Also in this case, the effect of tracing can be obtained as described above. Although it is preferable for the resin coating film 21 to have the same position in the axial direction as that of the reduced diameter portion 17e in order to obtain a shading effect, it is also conceivable to omit the reduced diameter portion 17e.
[0028]
As a method for processing the female spline, rolling, gear cutting, broaching, or the like can be used. As a male spline processing method, rolling, gear cutting, or the like can be used. In addition, the spline processing method for forming the resin coating film 21 is preferably a forming method by cutting such as gear cutting or broaching.
Further, each embodiment of the present invention is applied to a steering shaft 4 as a telescopic shaft with reference to FIG. 1, and the steering shaft 4 is configured in the same manner as the intermediate shafts 2, 201, 202 of the above-described embodiments. In this case, the upper shaft 10 may be an inner shaft portion and the lower shaft 11 may be an outer shaft portion. In addition, various modifications can be made within the scope of the claims of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle steering apparatus including an intermediate shaft as a telescopic shaft according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part of the intermediate shaft in FIG.
3 is an exploded perspective view of a main part of the intermediate shaft shown in FIG. 2. FIG.
4 is a schematic diagram showing a processing procedure of the outer shaft portion of the intermediate shaft shown in FIG. 2, and is shown in the order of FIGS. 4A, 4B, 4C, 4D, and 4E according to the processing order, and FIG. 4C and FIG. Shows an enlarged state during the formation of the spline.
FIG. 5 is a cross-sectional view of a main part of an intermediate shaft according to a second embodiment of the present invention.
6 is an exploded perspective view of a main part of the intermediate shaft shown in FIG.
7 is a schematic diagram showing a processing procedure of the inner shaft portion of the intermediate shaft shown in FIG. 5, and is shown in the order of FIG. 7A, FIG. 7B, FIG. 7C, FIG. 7D and FIG. 7D shows an enlarged state in the middle of spline formation.
FIG. 8 is a cross-sectional view of a main part of an intermediate shaft according to a third embodiment of the present invention.
FIG. 9 is a schematic diagram showing a processing procedure of an inner shaft portion according to a fourth embodiment of the present invention, which is shown in the order of FIGS. 9A, 9B, and 9C according to the processing order.
[Explanation of symbols]
2,201,202 Intermediate shaft (expandable shaft)
4 Steering shaft (expandable shaft)
10 Upper shaft (outer shaft)
11 Lower shaft (inner shaft)
13, 131 Outer shaft portion 13b Fitting hole 13e of outer shaft portion Reduced diameter portion 14, 141, 142 Inner shaft portion 14d Expanded portion 15 Female spline 16 Male spline 17, 19, 191 Hollow member 17c, 19c Inside of hollow member Peripherals 17d, 19b Hollow member outer periphery 17e Hollow member reduced diameter portion 19d Hollow member diameter expanded portion S Axial direction

Claims

In a telescopic shaft formed by inserting an inner shaft portion in which a male spline engaged with the female spline is formed in an axial direction into a fitting hole of an outer shaft portion in which a female spline is formed in an axial direction,
The outer shaft portion is made of a hollow member,
The outer periphery of the hollow member is provided with a reduced diameter portion and a pair of large diameter portions sandwiching the reduced diameter portion on both sides in the axial direction of the hollow member,
The female spline is formed in a portion corresponding to the reduced diameter portion and the pair of large diameter portions on the inner peripheral portion of the hollow member,
The reduced diameter part is continuous in the circumferential direction,
With respect to the thickness of the hollow member, it is formed relatively thin between the reduced diameter portion and the inner periphery, and is formed relatively thick between each large diameter portion and the inner periphery ,
The female spline includes a portion corresponding to the reduced diameter portion, and the female spline protrudes most radially inward of the hollow member at a central portion in the axial direction of the portion corresponding to the reduced diameter portion. Telescopic shaft to do.

In a telescopic shaft formed by inserting an inner shaft portion in which a male spline engaged with the female spline is formed in an axial direction into a fitting hole of an outer shaft portion in which a female spline is formed in an axial direction,
The inner shaft portion is made of a hollow member,
The inner periphery of the hollow member is provided with an enlarged diameter portion and a pair of small diameter portions sandwiching the enlarged diameter portion on both sides in the axial direction of the hollow member,
The male spline is formed on the outer peripheral part of the hollow member and corresponding to the enlarged diameter part and the pair of small diameter parts,
The enlarged diameter part is continuous in the circumferential direction,
With respect to the thickness of the hollow member, it is formed relatively thin between the enlarged diameter portion and the outer periphery, and is formed relatively thick between each small diameter portion and the outer periphery ,
The male spline includes a portion corresponding to the enlarged diameter portion, and the male spline protrudes most outward in the radial direction of the hollow member at the axial central portion in the portion corresponding to the enlarged diameter portion. Telescopic shaft to do.

In a telescopic shaft formed by inserting an inner shaft portion in which a male spline engaged with the female spline is formed in an axial direction into a fitting hole of an outer shaft portion in which a female spline is formed in an axial direction,
The outer shaft portion is composed of a first hollow member,
The outer periphery of the first hollow member is provided with a reduced diameter portion and a pair of large diameter portions sandwiching the reduced diameter portion on both sides in the axial direction of the first hollow member,
The female spline is formed in a portion corresponding to the reduced diameter portion and the pair of large diameter portions on the inner peripheral portion of the first hollow member,
The reduced diameter part is continuous in the circumferential direction,
Regarding the wall thickness of the first hollow member, a portion between the reduced diameter portion and the inner periphery is formed relatively thin, and a portion between each large diameter portion and the inner periphery is formed relatively thick. ,
The inner shaft portion is composed of a second hollow member,
The inner periphery of the second hollow member is provided with an enlarged diameter portion and a pair of small diameter portions sandwiching the enlarged diameter portion on both sides in the axial direction of the second hollow member,
The male spline is formed on a portion of the outer periphery of the second hollow member and corresponding to the enlarged diameter portion and the pair of narrow diameter portions,
The enlarged diameter part is continuous in the circumferential direction,
Regarding the thickness of the second hollow member, a portion between the enlarged diameter portion and the outer periphery is formed relatively thin, and a portion between each small diameter portion and the outer periphery is formed relatively thick,
The female spline includes a portion corresponding to the reduced diameter portion, and the female spline protrudes most radially inward of the first hollow member at a central portion in the axial direction of the portion corresponding to the reduced diameter portion ,
The male spline includes a portion corresponding to the enlarged diameter portion, and the male spline protrudes most outward in the radial direction of the second hollow member at the axial central portion in the portion corresponding to the enlarged diameter portion . Stretchable shaft characterized by

In a telescopic shaft formed by inserting an inner shaft portion in which a male spline engaged with the female spline is formed in an axial direction into a fitting hole of an outer shaft portion in which a female spline is formed in an axial direction, the outer shaft portion is The hollow member is provided with a reduced diameter portion and a pair of large diameter portions sandwiching the reduced diameter portion on both sides in the axial direction of the hollow member. The female spline is formed in a portion corresponding to the reduced diameter portion and the pair of large diameter portions, the reduced diameter portion is continuous in the circumferential direction, and the diameter of the hollow member is reduced. A telescopic shaft that is formed relatively thin between the portion and the inner periphery, and relatively thick between each large diameter portion and the inner periphery.
A method of manufacturing a telescopic shaft,
A method for producing a telescopic shaft, wherein the outer shaft portion is formed with a reduced diameter portion and a pair of large diameter portions on the outer periphery of the hollow member, and then a female spline is formed on the inner periphery of the hollow member. .

In a telescopic shaft formed by inserting an inner shaft portion in which a male spline engaged with the female spline is axially inserted into a fitting hole of an outer shaft portion in which a female spline is formed in the axial direction, the inner shaft portion is The hollow member is provided with an enlarged diameter portion and a pair of small diameter portions sandwiching the enlarged diameter portion on both sides in the axial direction of the hollow member. The male spline is formed in a portion corresponding to the enlarged diameter portion and the pair of narrow diameter portions, the enlarged diameter portion is continuous in the circumferential direction, and the diameter of the hollow member is increased in diameter. Stretchable shaft is formed with a relatively thin wall between the portion and the outer periphery, and is formed with a relatively thick wall between each small-diameter portion and the outer periphery.
A method of manufacturing a telescopic shaft,
A method of manufacturing a telescopic shaft, wherein the inner shaft portion is formed with a male spline on the outer periphery of the hollow member after an enlarged diameter portion and a pair of small diameter portions are formed on the inner periphery of the hollow member. .

In a telescopic shaft formed by inserting an inner shaft portion in which a male spline engaged with the female spline is formed in an axial direction into a fitting hole of an outer shaft portion in which a female spline is formed in an axial direction, the outer shaft portion is The first hollow member is provided with a reduced diameter portion and a pair of large diameter portions sandwiching the reduced diameter portion on both sides in the axial direction of the first hollow member. The female spline is formed in the inner peripheral portion of the first hollow member and corresponding to the reduced diameter portion and the pair of large diameter portions, and the reduced diameter portion is continuous in the circumferential direction. The thickness of the first hollow member is relatively thin between the reduced diameter portion and the inner periphery, and relatively thick between each large diameter portion and the inner periphery. The inner shaft portion is formed of a second hollow member, and an inner diameter of the second hollow member is provided with an enlarged diameter portion, and the enlarged diameter portion is provided with the second enlarged diameter portion. A pair of small-diameter portions sandwiched on both sides in the axial direction of the empty member, and a portion corresponding to the enlarged-diameter portion and the pair of small-diameter portions on the outer periphery of the second hollow member. A spline is formed, the enlarged diameter portion is continuous in the circumferential direction, and the thickness of the second hollow member is relatively thin between the enlarged diameter portion and the outer periphery. Stretchable shaft formed relatively thick between the outer circumference and the outer periphery
A method of manufacturing a telescopic shaft,
The outer shaft portion is formed with a reduced diameter portion and a pair of large diameter portions on the outer periphery of the first hollow member, and then a female spline is formed on the inner periphery of the first hollow member. The manufacture of a telescopic shaft, wherein a male spline is formed on the outer periphery of the second hollow member after an enlarged diameter portion and a pair of small diameter portions are formed on the inner periphery of the second hollow member Method.

2. The method for manufacturing a telescopic shaft according to claim 1 , wherein the outer shaft portion is formed with a reduced diameter portion and a pair of large diameter portions on the outer periphery of the hollow member, and then on the inner periphery of the hollow member. A method of manufacturing a telescopic shaft, wherein a spline is formed.

3. The method of manufacturing a telescopic shaft according to claim 2 , wherein the inner shaft portion is formed with an enlarged diameter portion and a pair of narrow diameter portions on the inner circumference of the hollow member, and then on the outer circumference of the hollow member. A method of manufacturing a telescopic shaft, wherein a spline is formed.

4. The method for manufacturing a telescopic shaft according to claim 3 , wherein the outer shaft portion is formed with a reduced diameter portion and a pair of large diameter portions on the outer periphery of the first hollow member, and then the first hollow portion is formed. A female spline is formed on the inner periphery of the member, and the inner shaft portion is formed with an enlarged diameter portion and a pair of narrow diameter portions on the inner periphery of the second hollow member, and then on the outer periphery of the second hollow member. A method of manufacturing a telescopic shaft, wherein a male spline is formed.