【書類名】 明細書
【発明の名称】 車輪用転がり軸受ユニット
【特許請求の範囲】
【請求項１】 外周面に懸架装置に支持する為の第一の取付フランジを、内周面に複列の外輪軌道を、それぞれ有する外輪と、外周面の一端寄り部分に車輪を支持する為の第二の取付フランジを、同じく他端寄り部分に第一の内輪軌道を、それぞれ設けた筒状の第一の内輪部材と、一端部をこの第一の内輪部材をがたつきなく外嵌固定する為の嵌合支持部とし、中間部外周面に第二の内輪軌道を設け、他端部を等速ジョイントの外輪となるハウジング部とした第二の内輪部材と、上記各外輪軌道と上記各内輪軌道との間にそれぞれ複数個ずつ転動自在に設けられた転動体とを備え、上記第一の内輪部材の中間部内周面に雌スプライン溝を形成した第一の小径部を、同じく他端部内周面にこの第一の小径部よりも大径の円筒面である第二の小径部を、互いに同心に設け、上記嵌合支持部の外周面は、上記第一の小径部に形成した雌スプライン溝と係合する雄スプライン溝を形成した第一の嵌合面部と、上記第二の小径部と嵌合する円筒面とした第二の嵌合面部とを、互いに同心に設けたものである車輪用転がり軸受ユニットに於いて、上記第一の嵌合面部の先端部を直径方向外方に塑性変形させてかしめ部を形成し、このかしめ部と上記第二の内輪部材の中間部外周面に設けた段部とで、上記第一の内輪部材の一部を軸方向両側から挟持する事により、この第一の内輪部材を上記第二の内輪部材に対して固定しており、この第二の内輪部材の径方向中間部に、一端側に開口する凹部を形成し、この凹部の奥面をこの第二の嵌合面部の内径側に存在させると共に、この凹部と上記ハウジング部との間を塞ぐ隔板部の一部を、上記第二の嵌合面部と径方向に関し重畳させており、上記第二の小径部とこの第二の嵌合面部との嵌合を締め代を持った嵌め合いとすると共に、上記第一、第二の内輪部材同士の組み合わせ時に、上記第二の小径部と上記第二の嵌合面部とが嵌合し始めるのに先立って上記雌スプライン溝と上記雄スプライン溝とが係合し始める様にした事を特徴とする車輪用転がり軸受ユニット。
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】
この発明に係る車輪用転がり軸受ユニットは、ＦＦ車（前置エンジン前輪駆動車）又は４ＷＤ車（四輪駆動車）の前輪等の駆動輪を、懸架装置に対して回転自在に支持する為に利用する。
【０００２】
【従来の技術】
車輪を懸架装置に対して回転自在に支持する為に、外輪と内輪とを転動体を介して回転自在に組み合わせた車輪用転がり軸受ユニットが、各種使用されている。又、操舵輪であると同時に駆動輪でもあるＦＦ車或は４ＷＤ車の前輪を支持する為の車輪用転がり軸受ユニットは、等速ジョイントと組み合わせて、車輪に付与された舵角に拘らず、駆動軸の回転を上記車輪に対して円滑に（等速性を確保して）伝達する必要がある。この様な等速ジョイントと組み合わせて、しかも小型且つ軽量に構成できる車輪用転がり軸受ユニットとして従来から、特開平１１−３７１４６号公報に記載されたものが知られている。
【０００３】
図４は、この公報に記載された従来構造を示している。車両への組み付け状態で、懸架装置に支持した状態で回転しない外輪１は、外周面にこの懸架装置に支持する為の第一の取付フランジ２を、内周面に複列の外輪軌道３、３を、それぞれ有する。上記外輪１の内側には、第一、第二の内輪部材４、５を組み合わせて成るハブ６を配置している。このうち第一の内輪部材４は、外周面の一端寄り（図４の左寄り）部分に車輪を支持する為の第二の取付フランジ７を、同じく他端寄り（図４の右寄り）部分に第一の内輪軌道８を、それぞれ設けた筒状に形成している。又、上記第一の内輪部材４の中間部内周面には、雌スプライン溝３２を形成した第一の小径部９を、同じく他端部（図４の右端部）内周面には、この第一の小径部９よりも大径の円筒面である第二の小径部１０を、互いに同心に設けている。
【０００４】
これに対して、第二の内輪部材５は、一端部（図４の左端部）を上記第一の内輪部材４をがたつきなく外嵌固定する為の嵌合支持部１１とし、中間部外周面に第二の内輪軌道１２を設け、他端部を等速ジョイント１３の外輪となるハウジング部１４としている。又、上記嵌合支持部１１の一端部には、この嵌合支持部１１よりも小径の雄ねじ部１５を設けている。又、この嵌合支持部１１の中間部外周面には、上記第一の小径部９に形成した雌スプライン溝３２と係合する雄スプライン溝３３を形成した第一の嵌合面部１６を、同じく他端部外周面には、上記第二の小径部１０と嵌合する円筒面とした第二の嵌合面部１７を、互いに同心に設けている。そして、上記嵌合支持部１１に、上記第一の内輪部材４を外嵌すると共に、上記第一の小径部９の内周面に形成した雌スプライン溝３２と上記第一の嵌合面部１６の外周面に形成した雄スプライン溝３３とをスプライン係合させている。この状態で、上記雄ねじ部１５にナット１８を螺合し、更に緊締して、上記第一、第二の内輪部材４、５同士を結合している。又、上記各外輪軌道３、３と上記第一、第二の内輪軌道８、１２との間にそれぞれ複数個ずつ転動体１９、１９を設ける事により、上記外輪１の内側に上記ハブ６を、回転自在に設けている。
【０００５】
更に、上記外輪１の両端開口部と上記ハブ６の中間部外周面との間には、ステンレス鋼板等の金属製で略円筒状のカバー２０ａ、２０ｂと、ゴムの如きエラストマー等の弾性材製で円環状のシールリング２１ａ、２１ｂとを設けている。これらカバー２０ａ、２０ｂ及びシールリング２１ａ、２１ｂは、上記複数の転動体１９、１９を設置した部分と外部とを遮断し、この部分に存在するグリースが外部に漏出するのを防止すると共に、この部分に雨水、塵芥等の異物が侵入する事を防止する。又、上記第二の内輪部材５の中間部内側には、この第二の内輪部材５の内側を塞ぐ隔板部２２を設けて、この第二の内輪部材５の剛性を確保すると共に、この第二の内輪部材５の先端（図４の左端）開口からこの第二の内輪部材５の内側に入り込んだ異物が、前記ハウジング部１４の内側に設けた等速ジョイント１３部分にまで達する事を防止している。
【０００６】
又、上記等速ジョイント１３は、上記ハウジング部１４と、内輪２３と、保持器２４と、複数個の玉２５とから成る。このうちの内輪２３は、エンジンによりトランスミッション及びデファレンシャルギヤを介して回転駆動される、図示しない駆動軸の先端部に固定される。この内輪２３の外周面には、それぞれが断面円弧形である複数の内側係合溝２６を、円周方向に亙り等間隔に、それぞれ円周方向に対し直角方向に形成している。又、上記ハウジング部１４の内周面で上記内側係合溝２６と対向する位置には、やはり断面円弧形である複数の外側係合溝２７を、円周方向に対し直角方向に形成している。又、上記保持器２４は、断面円弧状で全体を円環状に形成しており、上記内輪２３の外周面とハウジング部１４の内周面との間に挟持している。この保持器２４の円周方向複数個所で、上記内側、外側両係合溝２６、２７に整合する位置には、それぞれポケット２８を形成し、これら各ポケット２８の内側にそれぞれ上記各玉２５を保持している。これら各玉２５は、それぞれ上記各ポケット２８に保持された状態で、上記内側、外側両係合溝２６、２７に沿い転動自在である。又、上記ハウジング部１４の外周面には、このハウジング部１４の端部開口を塞ぐ筒状のブーツ（図示せず）の一端部を係止する為の係止溝２９を、全周に亙り形成している。
【０００７】
上述の様に構成する車輪用転がり軸受ユニットを車両に組み付ける際には、第一の取付フランジ２により外輪１を懸架装置に支持し、第二の取付フランジ７により駆動輪でもある前輪を第一の内輪部材４に固定する。又、エンジンによりトランスミッションを介して回転駆動される、図示しない駆動軸の先端部を、等速ジョイントを構成する内輪２３の内側にスプライン係合させる。自動車の走行時には、上記内輪２３の回転を、複数の玉２５を介してハブ６に伝達し、上記前輪を回転駆動する。
【０００８】
【発明が解決しようとする課題】
図４に示した従来の車輪用転がり軸受ユニットの場合、第一の内輪部材４を第二の内輪部材５の嵌合支持部１１に外嵌固定してハブ６を構成している。その為、ハブ６内に、第一の小径部９と第一の嵌合面部１６とのスプライン嵌合部と、第二の小径部１０と第二の嵌合面部１７との嵌合部とが存在する。ところで、車輪用転がり軸受ユニットの軸に相当するこのハブ６には、自動車への組み付け状態では、このハブ６を折り曲げようとする方向のモ−メントが、第二の取付フランジ７等から加わる荷重により発生する。従って、上記両嵌合部で上記モ−メントに対する曲げ剛性を高くする事は、上記ハブ６の曲がりを抑え、車輪用転がり軸受ユニットの安定性の向上に繋がる。特に、上記第二の小径部１０と第二の嵌合面部１７との嵌合を締め代を持った嵌め合いにする事が、上記曲げ剛性を向上させて、大きなモーメント荷重に対する安定性を確保する上からは好ましい。
【０００９】
ところが、上記第二の小径部１０と第二の嵌合面部１７との嵌合を締め代を持った嵌め合いにすると、上記第一、第二の内輪部材４、５同士の組み合わせ時に新たな問題が生じる。即ち、これら両内輪部材４、５同士を組み合わせるべく、このうちの第一の内輪部材４に第二の内輪部材５の嵌合支持部１１を挿入した際に、締め代を持った嵌め合いである上記第二の小径部１０と上記第二の嵌合面部１７とが先に嵌合し始めると、その後に、上記第一の小径部９の内周面に形成した雌スプライン溝３２と上記第一の嵌合面部１６の外周面に形成した雄スプライン溝３３とをスプライン系合させる為に円周方向の位相を合わせるべく、上記第一の内輪部材４と第二の内輪部材５とを相対回転させる事が難しくなる。この様な不都合を防止する為には、上記第一、第二の内輪部材４、５同士の組み合わせ時に、上記第二の小径部１０と上記第二の嵌合面部１７とが嵌合し始めるのに先立って、上記雌スプライン溝３２と上記雄スプライン溝３３とが係合し始める様に規制する事が好ましい。
本発明の車輪用転がり軸受ユニットは、上述の様な事情に鑑みて、車輪用転がり軸受ユニットの曲げ剛性を高める事ができ、しかも組立作業が容易な構造を実現すべく発明したものである。
【００１０】
【課題を解決するための手段】
本発明の車輪用転がり軸受ユニットは、前述した従来の車輪用転がり軸受ユニットと同様に、外周面に懸架装置に支持する為の第一の取付フランジを、内周面に複列の外輪軌道を、それぞれ有する外輪と、外周面の一端寄り部分に車輪を支持する為の第二の取付フランジを、同じく他端寄り部分に第一の内輪軌道を、それぞれ設けた筒状の第一の内輪部材と、一端部をこの第一の内輪部材をがたつきなく外嵌固定する為の嵌合支持部とし、中間部外周面に第二の内輪軌道を設け、他端部を等速ジョイントの外輪となるハウジング部とした第二の内輪部材と、上記各外輪軌道と上記各内輪軌道との間にそれぞれ複数個ずつ転動自在に設けられた転動体とを備える。このうち、上記第一の内輪部材の中間部内周面に雌スプライン溝を形成した第一の小径部を、同じく他端部内周面にこの第一の小径部よりも大径の円筒面である第二の小径部を、互いに同心に設けている。又、上記嵌合支持部の外周面は、上記第一の小径部に形成した雌スプライン溝と係合する雄スプライン溝を形成した第一の嵌合面部と、上記第二の小径部と嵌合する円筒面とした第二の嵌合面部とを、互いに同心に設けている。
特に、本発明の車輪用転がり軸受ユニットに於いては、上記第一の嵌合面部の先端部を直径方向外方に塑性変形させてかしめ部を形成している。そして、このかしめ部と上記第二の内輪部材の中間部外周面に設けた段部とで、上記第一の内輪部材の一部を軸方向両側から挟持する事により、この第一の内輪部材を上記第二の内輪部材に対して固定している。又、この第二の内輪部材の径方向中間部に、一端側に開口する凹部を形成し、この凹部の奥面をこの第二の嵌合面部の内径側に存在させている。これと共に、この凹部と上記ハウジング部との間を塞ぐ隔板部の一部を、上記第二の嵌合面部と径方向に関し重畳させている。更に、上記第二の小径部とこの第二の嵌合面部との嵌合を締め代を持った嵌め合いとすると共に、上記第一、第二の内輪部材同士の組み合わせ時に、上記第二の小径部と上記第二の嵌合面部とが嵌合し始めるのに先立って上記雌スプライン溝と上記雄スプライン溝とが係合し始める様にしている。
【００１１】
【作用】
上述の様に構成する本発明の車輪用転がり軸受ユニットの場合には、第二の小径部と第二の嵌合面部との嵌合を締め代を持った嵌め合いとしているので、従来構造の場合よりも曲げ剛性を高くして、走行時に加わる大きなモーメント荷重に拘らず、車輪用転がり軸受ユニット変形を抑えて、自動車の走行安定性の向上等を図れる。又、第一、第二の内輪部材同士の組み合わせ時に、上記第二の小径部と上記第二の嵌合面部とが嵌合し始めるのに先立って上記雌スプライン溝と上記雄スプライン溝とが係合し始める様に規制してるので、組立作業の容易化による製造コストの低減を図れる。
【００１２】
【発明の実施の形態】
図１〜２は、本発明に関する参考例の１例を示している。尚、本参考例の特徴は、組立作業を面倒にする事なく、車輪用転がり軸受ユニットのモ−メント荷重に対する曲げ剛性を高めるべく、第一の内輪部材４ａと第二の内輪部材５ａの嵌合支持部１１ａとの嵌合部分の構造を工夫した点にある。その他の部分の構造及び作用は、前述の図４に示した従来構造とほぼ同様であるから、同等部分には同一符号を付して重複する説明を省略若しくは簡略にし、以下、本参考例の特徴部分並びに上記従来構造と異なる部分を中心に説明する。
【００１３】
本参考例の車輪用転がり軸受ユニットのハブ６ａを構成する、筒状の第一の内輪部材４ａの中間部内周面に、雌スプライン溝３２ａを形成した第一の小径部９ａを、同じく他端部（図１〜２の右端部）内周面に、この第一の小径部９ａよりも大径の円筒面である第二の小径部１０ａを、互いに同心に設けている。一方、第一の内輪部材４ａと共にハブ６ａを構成する第二の内輪部材５ａの一端部（図１〜２の左端部）は、上記第一の内輪部材４ａをがたつきなく外嵌固定する為の嵌合支持部１１ａとしている。この嵌合支持部１１ａの中間部外周面には、上記第一の小径部９ａに形成した雌スプライン溝３２ａと係合する雄スプライン溝３３ａを形成した第一の嵌合面部１６ａを、他端部外周面には、上記第二の小径部１０ａと嵌合する円筒面とした第二の嵌合面部１７ａを、互いに同心に設けている。又、上記第二の小径部１０ａと第二の嵌合面部１７ａとの嵌合は、締め代を持った嵌め合いとしている。更に、上記第一の嵌合面部１６ａの軸方向長さＬ16a を、上記第二の小径部１０ａの軸方向長さＬ10a よりも長くしている。
【００１４】
上述の様に構成される第一、第二の内輪部材４ａ、５ａ同士を組み合わせるべく、図２に示す様に、第二の内輪部材５ａの嵌合支持部１１ａを第一の内輪部材４ａに挿入すると、先ず、上記第一の小径部９ａの内周面に形成した雌スプライン溝３２ａと上記第一の嵌合面部１６ａの外周面に形成した雄スプライン溝３３ａとがスプライン係合し始める。この際、これら両スプライン溝３２ａ、３３ａ同士をスプライン係合をさせる為に円周方向の位相を合わせるべく、上記第一の内輪部材４ａと第二の内輪部材５ａとを相対回転させる事は容易に行なえる。この様にして、上記両スプライン溝３２ａ、３３ａの端部同士を係合させた後に、締め代を持った嵌め合いである、上記第二の小径部１０ａと第二の嵌合面部１７ａとが嵌合し始めるので、更に、上記第二の内輪部材５ａを上記第一の内輪部材４ａ内に圧入する。そして、上記第二の内輪部材５ａの一端部に設けた雄ねじ部１５を前記第一の小径部９ａよりも突出させた後、図１に示す様に、この雄ねじ部１５にナット１８を螺合し、更に緊締する事により、上記第一、第二の内輪部材４ａ、５ａ同士を結合する。同時に、外輪１の内周面に設けた複列の外輪軌道３、３と上記第一、第二の内輪部材４ａ、５ａの外周面に設けた第一、第二の内輪軌道８、１２との間にそれぞれ複数個ずつ転動自在に設けた、各転動体１９、１９に、適切な予圧を付与する。
【００１５】
上述の様に構成する本参考例の車輪用転がり軸受ユニットにより、車輪を懸架装置に対して回転自在に支持する作用は、前述した従来の車輪用転がり軸受ユニットの場合と同様である。特に、本参考例の場合には、上記第二の小径部１０ａと第二の嵌合面部１７ａとの嵌合を締め代を持った嵌め合いにして、モ−メント荷重に対する曲げ剛性を高めている。従って、走行時に加わる大きなモーメント荷重に拘らず、ハブ６ａの変形を抑えて、車輪用転がり軸受ユニットを組み付けた自動車の走行安定性の向上等を図れる。又、上記第一の嵌合面部１６ａの軸方向長さＬ16a を上記第二の小径部１０ａの軸方向長さＬ10a よりも長くして、上記第一、第二の内輪部材４ａ、５ａ同士の組み合わせ時に、上記第二の小径部１０ａと上記第二の嵌合面部１７ａとが嵌合し始めるのに先立って上記第一の小径部９ａの内周面に形成した雌スプライン溝３２ａと上記第一の嵌合面部１６ａの外周面に形成した雄スプライン溝３３ａとのスプライン係合が始まる様に規制している。従って、ハブ６ａの組立作業を容易にできて、曲げ剛性が高く優れた性能を有する車輪用転がり軸受ユニットを低コストで実現できる。
【００１６】
尚、図示の例では、第一の嵌合面部１６ａの全長に亙って雄スプライン溝３３ａを形成している。但し、上記第二の小径部１０ａと上記第二の嵌合面部１７ａとが嵌合し始めるのに先立って上記第一の小径部９ａの内周面に形成した雌スプライン溝３２ａと上記第一の嵌合面部１６ａの外周面に形成した雄スプライン溝３３ａとのスプライン係合が始まる様にする為には、必ずしも第一の嵌合面部１６ａの全長に亙って雄スプライン溝３３ａを形成する必要はない。例えば、この第一の嵌合面部１６ａの先半部（図１〜２の左半部）にのみ雄スプライン溝３３ａを形成し、この第一の嵌合面部１６ａの基半部（図１〜２の右半部）は、この雄スプライン溝３３ａを形成した部分よりも小径の円筒面部としても良い。この場合でも、この円筒面部及び上記雄スプライン溝３３ａを形成した部分を含む、上記第一の嵌合面部１６ａの軸方向長さＬ16a は、上記第二の小径部１０ａの軸方向長さＬ10a よりも長くする。
【００１７】
次に、図３は、本発明の実施の形態の１例を示している。本例の車輪用転がり軸受ユニットのハブ６ｂを構成する第二の内輪部材５ｂの一端部（図３の左端部）に設けた嵌合支持部１１ｂの外周面は、一端寄り部分（図３の左寄り部分）に、その先端（図３の左端）まで雄スプライン溝３３ｂを形成した第一の嵌合面部１６ｂを、他端部（図３の右端部）に、円筒面とした第二の嵌合面部１７ｂを、互いに同心に設けている。上記嵌合支持部１１ｂを設けた第二の内輪部材５ｂと第一の内輪部材４ｂを組み合わせるべく、この嵌合支持部１１ｂを上記第一の内輪部材４ｂに挿入すると、先ず、上記第一の小径部９ｂの内周面に形成した雌スプライン溝３２ｂと上記第一の嵌合面部１６ｂの外周面に形成した雄スプライン溝３３ｂとがスプライン係合し始める。尚、この際は、上記第一の嵌合面部１６ｂは、先端までストレート形状である。その後に、締め代を持った嵌め合いである上記第二の小径部１０ｂと第二の嵌合面部１７ｂとが嵌合し始めるので、更に、上記第二の内輪部材５ｂを第一の内輪部材４ｂ内に圧入する。そして、この第一の内輪部材４ｂの軸方向他端面（図３の右端面）を、上記第二の内輪部材５ｂの中間部外周面に設けた段部３０に突き当てたまま、上記第一の嵌合面部１６ｂの先端部を直径方向外方に塑性変形させてかしめ部３１を形成する。この状態で上記第一の内輪部材４ｂは、上記段部３０と上記かしめ部３１とにより、軸方向両側から狭持されて、上記第二の内輪部材５ｂに対して固定される。尚、上記第一の内輪部材４ｂをこの段部３０に突き当てた状態で各転動体１９、１９に適正な予圧が付与される様に、上記段部３０等の位置を規制している。又、上記第二の内輪部材５ｂの径方向中間部に、一端側に開口する凹部３４を形成し、この凹部３４の奥面３５を、上記第二の嵌合面部１７ｂの内径側に存在させている。これと共に、この凹部３４と、等速ジョイント１３の外輪となるハウジング部１４との間を塞ぐ隔板部２２の一部を、上記第二の嵌合面部１７ｂと径方向に関し重畳させている。
【００１８】
上述の様に構成する本例の車輪用転がり軸受ユニットの場合には、前述した参考例の１例に比べて、ナット１８（図１参照）を使わない分、部品点数の削減による重量並びにコストの低減を図る事ができる。又、上記嵌合支持部１１ｂの先端まで雄スプライン溝３３ｂを形成して、上記第一の嵌合面部１６ｂの軸方向長さを長くしている。従って、締め代を持った嵌め合いである上記第二の小径部１０ｂと第二の嵌合面部１７ｂとの嵌合部の軸方向長さを長くでき、よりモ−メント荷重に対する曲げ剛性を高くする事ができる。尚、本発明を実施するに当たり、かしめ部３１となる嵌合支持部１１ｂの先端まで上記雄スプライン溝３３ｂを必ずしも形成する必要はないが、この嵌合支持部１１ｂの先端までスプライン加工をする方が、スプライン加工を途中までとする場合よりもコストがかからない他、雄セレ−ション溝３３ｂを形成した第一の嵌合面部１６ｂの軸方向長さが長くなる事で、第二の小径部１０ｂと第二の嵌合面部１７ｂとの嵌合長さを大きくしても、組立作業が面倒になる事がなく、結果として、よりモ−メント荷重に対する曲げ剛性を高くする事ができる。その他の構造及び作用は、前述した参考例の１例の場合と同様である。
【００１９】
【発明の効果】
本発明は、以上に述べた通り構成され作用するので、製作費の上昇を抑えつつ、車輪用転がり軸受ユニットの性能の向上を図れる。
【図面の簡単な説明】
【図１】
本発明に関する参考例の１例を示す部分断面図。
【図２】
組立工程を示す部分断面図。
【図３】
本発明の実施の形態の１例を示す部分断面図。
【図４】
従来構造の１例を示す部分断面図。
【符号の説明】
１ 外輪
２ 第一の取付フランジ
３ 外輪軌道
４、４ａ、４ｂ 第一の内輪部材
５、５ａ、５ｂ 第二の内輪部材
６、６ａ、６ｂ ハブ
７ 第二の取付フランジ
８ 第一の内輪軌道
９、９ａ、９ｂ 第一の小径部
１０、１０ａ、１０ｂ 第二の小径部
１１、１１ａ、１１ｂ 嵌合支持部
１２ 第二の内輪軌道
１３ 等速ジョイント
１４ ハウジング部
１５ 雄ねじ部
１６、１６ａ、１６ｂ 第一の嵌合面部
１７、１７ａ、１７ｂ 第二の嵌合面部
１８ ナット
１９ 転動体
２０ａ、２０ｂ カバー
２１ａ、２１ｂ シールリング
２２ 隔板部
２３ 内輪
２４ 保持器
２５ 玉
２６ 内側係合溝
２７ 外側係合溝
２８ ポケット
２９ 係止溝
３０ 段部
３１ かしめ部
３２、３２ａ、３２ｂ 雌スプライン溝
３３、３３ａ、３３ｂ 雄スプライン溝
３４ 凹部
３５ 奥面
[Document name] Specification [Title of invention] Rolling bearing unit for wheels [Claims]
1. To support an outer ring having a first mounting flange for supporting the suspension device on the outer peripheral surface, a double-row outer ring track on the inner peripheral surface, and a wheel at a portion closer to one end of the outer peripheral surface. The second mounting flange of the above is also provided with the first inner ring track on the other end side, and the first inner ring member in a tubular shape is provided, and one end of the first inner ring member is fitted without rattling. A second inner ring member having a fitting support portion for fixing, a second inner ring track provided on the outer peripheral surface of the intermediate portion, and a housing portion having the other end as the outer ring of the constant velocity joint, and each outer ring track. A first small-diameter portion having a plurality of rolling elements rotatably provided between the inner ring orbits and having a female spline groove formed on the inner peripheral surface of the intermediate portion of the first inner ring member. Similarly, a second small diameter portion, which is a cylindrical surface having a diameter larger than that of the first small diameter portion, is provided concentrically with each other on the inner peripheral surface of the other end portion, and the outer peripheral surface of the fitting support portion is the first small diameter portion. The first fitting surface portion having a male spline groove that engages with the female spline groove formed in the above and the second fitting surface portion having a cylindrical surface to be fitted with the second small diameter portion are concentric with each other. In the rolling bearing unit for wheels provided, the tip portion of the first fitting surface portion is plastically deformed outward in the radial direction to form a caulking portion, and the caulking portion and the second inner ring member are formed. The first inner ring member is fixed to the second inner ring member by sandwiching a part of the first inner ring member from both sides in the axial direction with the step portion provided on the outer peripheral surface of the intermediate portion of the above. A recess that opens to one end side is formed in the radial middle portion of the second inner ring member, and the inner surface of the recess is made to exist on the inner diameter side of the second fitting surface portion, and the recess and the recess. fitting of a portion of the diaphragm portion which closes between said housing portion and is superposed relates to the aforementioned second mating surface and radially, the second small diameter portion and the second mating surface Is fitted with a tightening allowance, and at the time of combining the first and second inner ring members, the second small diameter portion and the second fitting surface portion start to fit. A rolling bearing unit for wheels , characterized in that the female spline groove and the male spline groove start to engage with each other.
Description: TECHNICAL FIELD [Detailed description of the invention]
[0001]
[Technical field to which the invention belongs]
The rolling bearing unit for wheels according to the present invention is for rotatably supporting drive wheels such as front wheels of an FF vehicle (front engine front wheel drive vehicle) or a 4WD vehicle (four-wheel drive vehicle) with respect to a suspension device. Use.
0002.
[Conventional technology]
In order to rotatably support the wheels with respect to the suspension device, various rolling bearing units for wheels are used in which an outer ring and an inner ring are rotatably combined via a rolling element. In addition, the rolling bearing unit for wheels for supporting the front wheels of an FF vehicle or a 4WD vehicle, which is both a steering wheel and a driving wheel, is combined with a constant velocity joint regardless of the steering angle given to the wheels. It is necessary to smoothly transmit the rotation of the drive shaft to the wheels (ensuring constant velocity). As a rolling bearing unit for wheels that can be constructed in a compact and lightweight manner in combination with such a constant velocity joint, those described in Japanese Patent Application Laid-Open No. 11-37146 have been conventionally known.
0003
FIG. 4 shows the conventional structure described in this publication. The outer ring 1 that does not rotate while being mounted on the vehicle and supported by the suspension device has a first mounting flange 2 for supporting the suspension device on the outer peripheral surface, and a double row outer ring track 3 on the inner peripheral surface. 3 respectively. Inside the outer ring 1, a hub 6 formed by combining the first and second inner ring members 4 and 5 is arranged. Of these, the first inner ring member 4 has a second mounting flange 7 for supporting the wheel at one end (leftward in FIG. 4) of the outer peripheral surface, and a second mounting flange 7 at the other end (rightward in FIG. 4). One inner ring track 8 is formed in a tubular shape provided therein. Further, a first small diameter portion 9 having a female spline groove 32 formed on the inner peripheral surface of the intermediate portion of the first inner ring member 4 is provided on the inner peripheral surface of the other end portion (right end portion in FIG. 4). The second small diameter portion 10, which is a cylindrical surface having a diameter larger than that of the first small diameter portion 9, is provided concentrically with each other.
0004
On the other hand, in the second inner ring member 5, one end portion (left end portion in FIG. 4) is a fitting support portion 11 for externally fitting and fixing the first inner ring member 4 without rattling, and an intermediate portion. A second inner ring track 12 is provided on the outer peripheral surface, and the other end is a housing portion 14 which is an outer ring of the constant velocity joint 13. Further, at one end of the fitting support portion 11, a male screw portion 15 having a diameter smaller than that of the fitting support portion 11 is provided. Further, on the outer peripheral surface of the intermediate portion of the fitting support portion 11, a first fitting surface portion 16 having a male spline groove 33 formed in engagement with the female spline groove 32 formed in the first small diameter portion 9 is provided. Similarly, on the outer peripheral surface of the other end portion, a second fitting surface portion 17 which is a cylindrical surface to be fitted with the second small diameter portion 10 is provided concentrically with each other. Then, the first inner ring member 4 is externally fitted to the fitting support portion 11, and the female spline groove 32 and the first fitting surface portion 16 formed on the inner peripheral surface of the first small diameter portion 9 are formed. The male spline groove 33 formed on the outer peripheral surface of the above is spline-engaged. In this state, the nut 18 is screwed into the male screw portion 15 and further tightened to connect the first and second inner ring members 4 and 5 to each other. Further, by providing a plurality of rolling elements 19 and 19 between the outer ring tracks 3 and 3 and the first and second inner ring tracks 8 and 12, respectively, the hub 6 is provided inside the outer ring 1. , It is provided so that it can rotate.
0005
Further, between the openings at both ends of the outer ring 1 and the outer peripheral surface of the intermediate portion of the hub 6, metal covers 20a and 20b made of metal such as stainless steel plate and elastic materials such as elastomer such as rubber are used. The annular seal rings 21a and 21b are provided. The covers 20a, 20b and the seal rings 21a, 21b block the portion where the plurality of rolling elements 19 and 19 are installed from the outside, prevent the grease existing in this portion from leaking to the outside, and prevent the grease from leaking to the outside. Prevents foreign matter such as rainwater and dust from entering the part. Further, a partition plate portion 22 for closing the inside of the second inner ring member 5 is provided inside the intermediate portion of the second inner ring member 5 to secure the rigidity of the second inner ring member 5 and to secure the rigidity of the second inner ring member 5. Foreign matter that has entered the inside of the second inner ring member 5 through the opening at the tip (left end in FIG. 4) of the second inner ring member 5 reaches the constant velocity joint 13 portion provided inside the housing portion 14. It is preventing.
0006
Further, the constant velocity joint 13 includes the housing portion 14, the inner ring 23, the cage 24, and a plurality of balls 25. The inner ring 23 is fixed to the tip of a drive shaft (not shown), which is rotationally driven by the engine via a transmission and a differential gear. On the outer peripheral surface of the inner ring 23, a plurality of inner engaging grooves 26 each having an arc-shaped cross section are formed at equal intervals in the circumferential direction in a direction perpendicular to the circumferential direction. Further, at a position facing the inner engaging groove 26 on the inner peripheral surface of the housing portion 14, a plurality of outer engaging grooves 27 also having an arc-shaped cross section are formed in a direction perpendicular to the circumferential direction. ing. Further, the cage 24 has an arcuate cross section and is formed in an annular shape as a whole, and is sandwiched between the outer peripheral surface of the inner ring 23 and the inner peripheral surface of the housing portion 14. Pockets 28 are formed at a plurality of locations in the circumferential direction of the cage 24 at positions aligned with the inner and outer engaging grooves 26 and 27, and the balls 25 are placed inside the pockets 28, respectively. keeping. Each of these balls 25 can roll along the inner and outer engaging grooves 26 and 27 while being held in the respective pockets 28. Further, on the outer peripheral surface of the housing portion 14, a locking groove 29 for locking one end of a tubular boot (not shown) that closes the end opening of the housing portion 14 is provided all around. Is forming.
0007
When assembling the rolling bearing unit for wheels configured as described above to the vehicle, the outer ring 1 is supported by the suspension device by the first mounting flange 2, and the front wheel, which is also the driving wheel, is first supported by the second mounting flange 7. It is fixed to the inner ring member 4 of. Further, the tip of a drive shaft (not shown), which is rotationally driven by the engine via a transmission, is spline-engaged with the inside of the inner ring 23 constituting the constant velocity joint. When the automobile is running, the rotation of the inner ring 23 is transmitted to the hub 6 via the plurality of balls 25, and the front wheel is rotationally driven.
0008
[Problems to be Solved by the Invention]
In the case of the conventional rolling bearing unit for wheels shown in FIG. 4, the hub 6 is formed by externally fitting and fixing the first inner ring member 4 to the fitting support portion 11 of the second inner ring member 5. Therefore, in the hub 6, a spline fitting portion between the first small diameter portion 9 and the first fitting surface portion 16 and a fitting portion between the second small diameter portion 10 and the second fitting surface portion 17 are provided. Exists. By the way, in this hub 6 corresponding to the shaft of the rolling bearing unit for wheels, a moment in the direction of bending the hub 6 is applied from a second mounting flange 7 or the like in a state of being assembled to an automobile. Caused by. Therefore, increasing the flexural rigidity of the two fitting portions with respect to the moment suppresses the bending of the hub 6, which leads to the improvement of the stability of the rolling bearing unit for wheels. In particular, fitting the second small diameter portion 10 and the second fitting surface portion 17 with a tightening allowance improves the bending rigidity and secures stability against a large moment load. It is preferable from the viewpoint of
0009
However, if the fitting of the second small diameter portion 10 and the second fitting surface portion 17 is made to fit with a tightening allowance, a new combination of the first and second inner ring members 4 and 5 is performed. Problems arise. That is, when the fitting support portion 11 of the second inner ring member 5 is inserted into the first inner ring member 4 in order to combine these two inner ring members 4 and 5, the fitting with a tightening allowance is obtained. When the second small diameter portion 10 and the second fitting surface portion 17 begin to fit first, then the female spline groove 32 formed on the inner peripheral surface of the first small diameter portion 9 and the above The first inner ring member 4 and the second inner ring member 5 are combined with each other in order to match the phases in the circumferential direction with the male spline groove 33 formed on the outer peripheral surface of the first fitting surface portion 16. It becomes difficult to rotate relative to each other. In order to prevent such inconvenience, when the first and second inner ring members 4 and 5 are combined, the second small diameter portion 10 and the second fitting surface portion 17 start to fit. It is preferable to regulate the female spline groove 32 and the male spline groove 33 so as to start engaging with each other prior to the above.
The rolling bearing unit for wheels of the present invention has been invented in view of the above circumstances in order to realize a structure capable of increasing the bending rigidity of the rolling bearing unit for wheels and facilitating assembly work.
0010
[Means for solving problems]
The rolling bearing unit for wheels of the present invention has a first mounting flange for supporting the suspension device on the outer peripheral surface and a double-row outer ring track on the inner peripheral surface, similarly to the conventional rolling bearing unit for wheels described above. , A tubular first inner ring member provided with an outer ring, a second mounting flange for supporting the wheel at one end of the outer peripheral surface, and a first inner ring track at the other end. One end is used as a fitting support for fixing the first inner ring member to the outer ring without rattling, a second inner ring track is provided on the outer peripheral surface of the middle part, and the other end is the outer ring of the constant velocity joint. It is provided with a second inner ring member serving as a housing portion, and a plurality of rolling elements rotatably provided between the outer ring raceways and the inner ring raceways. Of these, the first small-diameter portion having a female spline groove formed on the inner peripheral surface of the intermediate portion of the first inner ring member is also a cylindrical surface having a larger diameter than the first small-diameter portion on the inner peripheral surface of the other end portion. The second small diameter portions are provided concentrically with each other. Further, the outer peripheral surface of the fitting support portion is fitted with the first fitting surface portion having a male spline groove formed to engage with the female spline groove formed in the first small diameter portion and the second small diameter portion. A second fitting surface portion formed as a matching cylindrical surface is provided concentrically with each other.
In particular, in the rolling bearing unit for wheels of the present invention, the tip portion of the first fitting surface portion is plastically deformed outward in the radial direction to form a crimped portion. Then, by sandwiching a part of the first inner ring member from both sides in the axial direction between the crimped portion and the step portion provided on the outer peripheral surface of the intermediate portion of the second inner ring member, the first inner ring member is formed. Is fixed to the second inner ring member. Further, a concave portion that opens to one end side is formed in the radial intermediate portion of the second inner ring member, and the inner surface of the concave portion is present on the inner diameter side of the second fitting surface portion. At the same time, a part of the partition plate portion that closes the recess and the housing portion is overlapped with the second fitting surface portion in the radial direction. Furthermore, with the fitting having an allowance tighten the fitting of the second small diameter portion and the second mating surface, the first, when the combination between the second inner ring member, the second The female spline groove and the male spline groove start to engage with each other prior to the small diameter portion and the second fitting surface portion starting to fit.
0011
[Action]
In the case of the rolling bearing unit for wheels of the present invention configured as described above, the fitting between the second small diameter portion and the second fitting surface portion is a fitting with a tightening allowance, and thus has a conventional structure. The flexural rigidity can be made higher than in the case, and the deformation of the rolling bearing unit for wheels can be suppressed regardless of the large moment load applied during running, and the running stability of the automobile can be improved. Further, when the first and second inner ring members are combined with each other, the female spline groove and the male spline groove are formed prior to the start of fitting between the second small diameter portion and the second fitting surface portion. Since it is regulated to start engaging, the manufacturing cost can be reduced by facilitating the assembly work.
0012
BEST MODE FOR CARRYING OUT THE INVENTION
FIGS. 1 and 2 show an example of a reference example relating to the present invention. The feature of this reference example is that the first inner ring member 4a and the second inner ring member 5a are fitted in order to increase the flexural rigidity of the rolling bearing unit for wheels with respect to the moment load without making the assembly work troublesome. The point is that the structure of the fitting portion with the joint support portion 11a is devised. The construction and function of other portions are substantially the same as the conventional construction shown in FIG. 4 described above, to omit or simplify the description are indicated by the same reference numerals to like parts, hereinafter the present embodiment The feature portion and the portion different from the conventional structure will be mainly described.
0013
The other end of the first small diameter portion 9a having a female spline groove 32a formed on the inner peripheral surface of the intermediate portion of the first cylindrical inner ring member 4a constituting the hub 6a of the rolling bearing unit for wheels of this reference example. A second small-diameter portion 10a, which is a cylindrical surface having a diameter larger than that of the first small-diameter portion 9a, is provided concentrically with each other on the inner peripheral surface of the portion (right end portion in FIGS. 1 and 2). On the other hand, one end portion (left end portion in FIGS. 1 and 2) of the second inner ring member 5a constituting the hub 6a together with the first inner ring member 4a is externally fitted and fixed to the first inner ring member 4a without rattling. The fitting support portion 11a for this purpose is used. On the outer peripheral surface of the intermediate portion of the fitting support portion 11a, a first fitting surface portion 16a having a male spline groove 33a formed in engagement with the female spline groove 32a formed in the first small diameter portion 9a is formed at the other end. A second fitting surface portion 17a, which is a cylindrical surface to be fitted with the second small diameter portion 10a, is provided concentrically with each other on the outer peripheral surface of the portion. Further, the fitting of the second small diameter portion 10a and the second fitting surface portion 17a is a fitting having a tightening allowance. Further, the axial length L 16a of the first fitting surface portion 16a is made longer than the axial length L 10a of the second small diameter portion 10a.
0014.
As shown in FIG. 2, in order to combine the first and second inner ring members 4a and 5a configured as described above, the fitting support portion 11a of the second inner ring member 5a is used as the first inner ring member 4a. Upon insertion, first, the female spline groove 32a formed on the inner peripheral surface of the first small diameter portion 9a and the male spline groove 33a formed on the outer peripheral surface of the first fitting surface portion 16a begin to spline engage. At this time, it is easy to relatively rotate the first inner ring member 4a and the second inner ring member 5a in order to match the phases in the circumferential direction in order to engage the spline grooves 32a and 33a with each other. You can go to. In this way, after the ends of both spline grooves 32a and 33a are engaged with each other, the second small diameter portion 10a and the second fitting surface portion 17a, which are fitted with a tightening allowance, are formed. Since the fitting starts, the second inner ring member 5a is further press-fitted into the first inner ring member 4a. Then, after the male screw portion 15 provided at one end of the second inner ring member 5a is projected from the first small diameter portion 9a, the nut 18 is screwed into the male screw portion 15 as shown in FIG. Then, by further tightening, the first and second inner ring members 4a and 5a are connected to each other. At the same time, the double-row outer ring tracks 3 and 3 provided on the inner peripheral surface of the outer ring 1 and the first and second inner ring tracks 8 and 12 provided on the outer peripheral surfaces of the first and second inner ring members 4a and 5a. Appropriate preload is applied to each of the rolling elements 19 and 19, which are provided between the rolling elements 19 and 19 so as to be rollable.
0015.
The action of rotatably supporting the wheel with respect to the suspension device by the rolling bearing unit for wheels of this reference example configured as described above is the same as that of the conventional rolling bearing unit for wheels described above. In particular, in the case of this reference example , the fitting of the second small diameter portion 10a and the second fitting surface portion 17a is fitted with a tightening allowance to increase the bending rigidity with respect to the moment load. There is. Therefore, regardless of the large moment load applied during traveling, the deformation of the hub 6a can be suppressed, and the traveling stability of the automobile to which the rolling bearing unit for wheels is assembled can be improved. Further, the axial length L 16a of the first fitting surface portion 16a is made longer than the axial length L 10a of the second small diameter portion 10a so that the first and second inner ring members 4a and 5a are formed. At the time of combination with each other, the female spline groove 32a formed on the inner peripheral surface of the first small diameter portion 9a prior to the start of fitting between the second small diameter portion 10a and the second fitting surface portion 17a. The spline engagement with the male spline groove 33a formed on the outer peripheral surface of the first fitting surface portion 16a is regulated so as to start. Therefore, the assembly work of the hub 6a can be easily performed, and a rolling bearing unit for wheels having high bending rigidity and excellent performance can be realized at low cost.
0016.
In the illustrated example, the male spline groove 33a is formed over the entire length of the first fitting surface portion 16a. However, the female spline groove 32a and the first one formed on the inner peripheral surface of the first small diameter portion 9a prior to the start of fitting between the second small diameter portion 10a and the second fitting surface portion 17a. In order to start spline engagement with the male spline groove 33a formed on the outer peripheral surface of the fitting surface portion 16a, the male spline groove 33a is not necessarily formed over the entire length of the first fitting surface portion 16a. No need. For example, a male spline groove 33a is formed only in the front half portion (left half portion in FIGS. 1 and 2) of the first fitting surface portion 16a, and the base half portion (FIGS. 1 to 2) of the first fitting surface portion 16a. The right half portion of 2) may be a cylindrical surface portion having a diameter smaller than the portion where the male spline groove 33a is formed. Even in this case, the axial length L 16a of the first fitting surface portion 16a including the cylindrical surface portion and the portion forming the male spline groove 33a is the axial length L of the second small diameter portion 10a. Make it longer than 10a.
[0017]
Next, FIG. 3 shows an example of an embodiment of the present invention. The outer peripheral surface of the fitting support portion 11b provided at one end (left end in FIG. 3) of the second inner ring member 5b constituting the hub 6b of the rolling bearing unit for wheels of this example is a portion closer to one end (FIG. 3). A first fitting surface portion 16b having a male spline groove 33b formed up to its tip (left end in FIG. 3) at the left end portion) is provided as a cylindrical surface at the other end (right end portion in FIG. 3). The mating portions 17b are provided concentrically with each other. When the fitting support portion 11b is inserted into the first inner ring member 4b in order to combine the second inner ring member 5b provided with the fitting support portion 11b and the first inner ring member 4b, first, the first inner ring member 4b The female spline groove 32b formed on the inner peripheral surface of the small diameter portion 9b and the male spline groove 33b formed on the outer peripheral surface of the first fitting surface portion 16b begin to spline engage. At this time, the first fitting surface portion 16b has a straight shape up to the tip. After that, the second small diameter portion 10b and the second fitting surface portion 17b, which are fitted with a tightening allowance, begin to fit, so that the second inner ring member 5b is further combined with the first inner ring member. Press-fit into 4b. Then, while the other end surface (right end surface in FIG. 3) of the first inner ring member 4b in the axial direction is abutted against the step portion 30 provided on the outer peripheral surface of the intermediate portion of the second inner ring member 5b, the first The tip of the fitting surface portion 16b of the above is plastically deformed outward in the radial direction to form the crimped portion 31. In this state, the first inner ring member 4b is sandwiched from both sides in the axial direction by the step portion 30 and the caulking portion 31, and is fixed to the second inner ring member 5b. The position of the step portion 30 and the like is regulated so that an appropriate preload is applied to the rolling elements 19 and 19 in a state where the first inner ring member 4b is abutted against the step portion 30. Further, a recess 34 that opens to one end side is formed in the radial intermediate portion of the second inner ring member 5b, and the inner surface 35 of the recess 34 is present on the inner diameter side of the second fitting surface portion 17b. ing. At the same time, a part of the partition plate portion 22 that closes between the recess 34 and the housing portion 14 that is the outer ring of the constant velocity joint 13 is superposed on the second fitting surface portion 17b in the radial direction.
0018
In the case of the rolling bearing unit for wheels of this example configured as described above, the weight and cost due to the reduction in the number of parts are reduced because the nut 18 (see FIG. 1) is not used as compared with the example of the reference example described above. Can be reduced. Further, a male spline groove 33b is formed up to the tip of the fitting support portion 11b to increase the axial length of the first fitting surface portion 16b. Therefore, the axial length of the fitting portion between the second small diameter portion 10b and the second fitting surface portion 17b, which are fitted with a tightening allowance, can be increased, and the bending rigidity with respect to the moment load can be further increased. Can be done. In carrying out the present invention, it is not always necessary to form the male spline groove 33b up to the tip of the fitting support portion 11b serving as the caulking portion 31, but a person who performs spline processing to the tip of the fitting support portion 11b. However, it costs less than the case where the spline processing is halfway, and the axial length of the first fitting surface portion 16b forming the male selection groove 33b becomes longer, so that the second small diameter portion 10b Even if the fitting length between the and the second fitting surface portion 17b is increased, the assembly work is not troublesome, and as a result, the bending rigidity with respect to the moment load can be further increased. Other structures and operations are the same as in the case of one of the above-mentioned reference examples.
0019
【Effect of the invention】
Since the present invention is configured and operates as described above, it is possible to improve the performance of the rolling bearing unit for wheels while suppressing an increase in manufacturing cost.
[Simple explanation of drawings]
FIG. 1
FIG. 3 is a partial cross-sectional view showing an example of a reference example relating to the present invention.
FIG. 2
Partial sectional view showing an assembly process.
FIG. 3
FIG. 3 is a partial cross-sectional view showing an example of an embodiment of the present invention.
FIG. 4
A partial cross-sectional view showing an example of a conventional structure.
[Explanation of symbols]
1 Outer ring 2 First mounting flange 3 Outer ring track 4, 4a, 4b First inner ring member 5, 5a, 5b Second inner ring member 6, 6a, 6b Hub 7 Second mounting flange 8 First inner ring track 9 , 9a, 9b 1st small diameter part 10, 10a, 10b 2nd small diameter part 11, 11a, 11b Fitting support part 12 2nd inner ring track 13 Constant velocity joint 14 Housing part 15 Male thread part 16, 16a, 16b No. One fitting surface part 17, 17a, 17b Second fitting surface part 18 Nut 19 Rolling body 20a, 20b Cover 21a, 21b Seal ring 22 Separation plate part 23 Inner ring 24 Cage 25 Ball 26 Inner engagement groove 27 Outer engagement Groove 28 Pocket 29 Locking groove 30 Steps 31 Crimping part 32, 32a, 32b Female spline groove 33, 33a, 33b Male spline groove
34 recess
35 back
