JP4432152B2

JP4432152B2 - Rolling bearing unit for wheels

Info

Publication number: JP4432152B2
Application number: JP21482799A
Authority: JP
Inventors: 英男大内
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 1999-07-29
Filing date: 1999-07-29
Publication date: 2010-03-17
Anticipated expiration: 2019-07-29
Also published as: JP2001039103A

Description

【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、外周面の軸方向一端寄り（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、同じく軸方向他端寄り（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の軸方向中間部内周面には、雌スプライン溝３２を形成した第一の小径部９を、同じく軸方向他端部（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。尚、本明細書中で、「軸方向」とは各図面の左右方向を、「径方向」とは各図面の上下方向をそれぞれ指す。
【０００４】
これに対して、第二の内輪部材５は、軸方向一端部（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、軸方向中間部外周面に第二の内輪軌道１２を設け、軸方向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の軸方向一端部には、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の軸方向中間部外周面には、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、同じく軸方向他端部外周面には、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の軸方向両端開口部と上記ハブ６の軸方向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の軸方向中間部内側には、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の軸方向端部開口を塞ぐ筒状のブーツ（図示せず）の軸方向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、外周面の軸方向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、同じく軸方向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、軸方向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、軸方向中間部外周面に第二の内輪軌道を設け、軸方向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軸方向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、同じく軸方向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軸方向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軸方向中間部乃至一端部でこの第二の内輪部材の径方向中央部に、軸方向一端側に開口する凹部を形成し、この凹部の奥面を上記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。又、上記嵌合支持部の先端まで上記雄スプライン溝を形成している。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の変形を抑えて、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いるので、組立作業の容易化による製造コストの低減を図れる。
又、嵌合支持部の先端まで雄スプライン溝を形成して、第一の嵌合面部の軸方向長さを長くしている為、締め代を持った嵌め合いである上記第二の小径部と第二の嵌合面部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。
【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の軸方向中間部内周面に、雌スプライン溝３２ａを形成した第一の小径部９ａを、同じく軸方向他端部（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の軸方向一端部（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の軸方向中間部外周面には、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、軸方向他端部外周面には、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Ｌ_16aを、上記第二の小径部１０ａの軸方向長さＬ_10a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の軸方向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Ｌ_16aを上記第二の小径部１０ａの軸方向長さＬ_10a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Ｌ_16aは、上記第二の小径部１０ａの軸方向長さＬ_10a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の軸方向一端部（図３の左端部）に設けた嵌合支持部１１ｂの外周面は、軸方向一端寄り部分（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、軸方向他端部（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の軸方向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の軸方向中間部乃至一端部で、この第二の内輪部材５ｂの径方向中央部に、軸方向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。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[0001]
BACKGROUND OF THE INVENTION
The wheel rolling bearing unit according to the present invention is configured to rotatably support a drive wheel such as a front wheel 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]
[Prior art]
In order to rotatably support a wheel with respect to a suspension device, various types of wheel rolling bearing units are used in which an outer ring and an inner ring are rotatably combined via rolling elements. In addition, the wheel rolling bearing unit for supporting the front wheel of the FF vehicle or 4WD vehicle which is the steering wheel as well as the drive wheel is combined with the constant velocity joint, regardless of the steering angle given to the wheel. It is necessary to transmit the rotation of the drive shaft to the wheel smoothly (with a constant speed). 2. Description of the Related Art Conventionally, a rolling bearing unit for a wheel that can be configured in a small size and light weight in combination with such a constant velocity joint is disclosed in Japanese Patent Application Laid-Open No. 11-37146.
[0003]
FIG. 4 shows a conventional structure described in this publication. The outer ring 1 that does not rotate in a state of being mounted on a vehicle while being supported by a 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. A hub 6 formed by combining the first and second inner ring members 4 and 5 is disposed inside the outer ring 1. Of these, the first inner ring member 4 has a second mounting flange 7 for supporting the wheel at a portion near the axial end of the outer peripheral surface (leftward in FIG. 4), and also close to the other axial end (rightward in FIG. 4). The first inner ring raceway 8 is formed in a cylindrical shape provided in each part. Further, the first small-diameter portion 9 formed with the female spline groove 32 is formed on the inner peripheral surface of the first inner ring member 4 in the axial direction, and the inner peripheral surface of the other axial end portion (the right end portion in FIG. 4). The second small-diameter portion 10 that is a cylindrical surface having a diameter larger than that of the first small-diameter portion 9 is provided concentrically with each other. In this specification, “axial direction” refers to the horizontal direction of each drawing, and “radial direction” refers to the vertical direction of each drawing.
[0004]
On the other hand, the second inner ring member 5 serves as a fitting support part 11 for externally fixing and fixing the first inner ring member 4 without rattling at one axial end part (left end part in FIG. 4). A second inner ring raceway 12 is provided on the outer peripheral surface in the axial direction intermediate portion, and the other end portion in the axial direction serves as a housing portion 14 serving as an outer ring of the constant velocity joint 13. Further, a male screw portion 15 having a smaller diameter than the fitting support portion 11 is provided at one end portion in the axial direction of the fitting support portion 11. Further, a first fitting surface portion 16 in which a male spline groove 33 that engages with the female spline groove 32 formed in the first small diameter portion 9 is formed on the outer peripheral surface in the axial direction intermediate portion of the fitting support portion 11. Similarly, on the outer peripheral surface of the other end in the axial direction , a second fitting surface portion 17 that is a cylindrical surface that fits the second small diameter portion 10 is provided concentrically with each other. Then, the first inner ring member 4 is fitted on the fitting support portion 11, and the female spline groove 32 formed on the inner peripheral surface of the first small diameter portion 9 and the first fitting surface portion 16. The male spline groove 33 formed on the outer peripheral surface of the first spline is engaged with the spline. In this state, the nut 18 is screwed into the male screw portion 15 and further tightened to join the first and second inner ring members 4 and 5 together. Further, by providing a plurality of rolling elements 19, 19 between the outer ring raceways 3, 3 and the first and second inner ring raceways 8, 12, the hub 6 is placed inside the outer ring 1. , Is provided rotatably.
[0005]
Furthermore, between the axially intermediate portion outer peripheral surface of the axial end opening and the hub 6 of the outer ring 1, a stainless steel plate of metal with a substantially cylindrical cover 20a, 20b and, a rubber such as elastomer or the like The ring-shaped seal rings 21a and 21b are provided. The covers 20a and 20b and the seal rings 21a and 21b block the portion where the plurality of rolling elements 19 and 19 are installed from the outside, and prevent the grease existing in this portion from leaking outside. Prevents foreign matter such as rainwater and dust from entering the area. In addition, a partition 22 that closes the inside of the second inner ring member 5 is provided on the inner side in the axial direction of the second inner ring member 5 to ensure the rigidity of the second inner ring member 5. The foreign matter that has entered the inside of the second inner ring member 5 through the opening (left end in FIG. 4) of the second inner ring member 5 reaches the constant velocity joint 13 provided inside the housing portion 14. To prevent things.
[0006]
The constant velocity joint 13 includes the housing portion 14, an inner ring 23, a cage 24, and a plurality of balls 25. Of these, the inner ring 23 is fixed to the tip of a drive shaft (not shown) that 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 engagement grooves 26, each having an arc shape in cross section, are formed at equal intervals in the circumferential direction and perpendicular to the circumferential direction. Further, a plurality of outer engagement grooves 27 having an arcuate cross section are formed in a direction perpendicular to the circumferential direction at a position facing the inner engagement groove 26 on the inner peripheral surface of the housing portion 14. ing. The cage 24 has an arc shape in cross section and is formed in an annular shape as a whole, and is held between the outer peripheral surface of the inner ring 23 and the inner peripheral surface of the housing portion 14. A plurality of pockets 28 are formed at positions corresponding to the inner and outer engaging grooves 26 and 27 at a plurality of locations in the circumferential direction of the cage 24, and the balls 25 are respectively placed inside the pockets 28. keeping. These balls 25 can roll along the inner and outer engaging grooves 26 and 27 while being held in the pockets 28, respectively. Further, a locking groove 29 for locking one axial end of a cylindrical boot (not shown) that closes the axial end opening of the housing 14 is formed on the outer peripheral surface of the housing 14. It is formed over the entire circumference.
[0007]
When the rolling bearing unit for a wheel configured as described above is assembled to a vehicle, the outer ring 1 is supported on 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. The inner ring member 4 is fixed. Further, the tip of a drive shaft (not shown) that is rotationally driven by the engine via the transmission is spline-engaged with the inner side of the inner ring 23 that constitutes the constant velocity joint. When the automobile is running, the rotation of the inner ring 23 is transmitted to the hub 6 via a 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 wheel rolling bearing unit shown in FIG. 4, the first inner ring member 4 is externally fitted and fixed to the fitting support portion 11 of the second inner ring member 5 to constitute the hub 6. 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. Exists. By the way, the load applied to the hub 6 corresponding to the shaft of the rolling bearing unit for the wheel from the second mounting flange 7 or the like is a moment in a direction in which the hub 6 is bent when the hub 6 is assembled to the automobile. Caused by. Therefore, increasing the bending rigidity with respect to the moment at both the fitting portions suppresses the bending of the hub 6 and leads to an improvement in the stability of the wheel rolling bearing unit. In particular, the fitting between the second small diameter portion 10 and the second fitting surface portion 17 is a fitting with a tightening margin, thereby improving the bending rigidity and ensuring stability against a large moment load. From the top, it is preferable.
[0009]
However, if the fitting of the second small diameter portion 10 and the second fitting surface portion 17 is a fitting with a tightening margin, a new one is added when the first and second inner ring members 4 and 5 are combined. 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 the inner ring members 4 and 5 with each other, When the certain second small-diameter portion 10 and the second fitting surface portion 17 start to be fitted first, then the female spline groove 32 formed on the inner peripheral surface of the first small-diameter portion 9 and the above-mentioned The first inner ring member 4 and the second inner ring member 5 are connected to each other in order to match the phases in the circumferential direction so that the male spline groove 33 formed on the outer peripheral surface of the first fitting surface portion 16 is splined. It becomes difficult to make relative rotation. In order to prevent such inconvenience, the second small diameter portion 10 and the second fitting surface portion 17 start to be fitted when the first and second inner ring members 4 and 5 are combined. Prior to this, it is preferable to restrict the female spline groove 32 and the male spline groove 33 so as to start to engage with each other.
The wheel rolling bearing unit of the present invention has been invented to realize a structure that can increase the bending rigidity of the wheel rolling bearing unit and can be easily assembled in view of the above-described circumstances.
[0010]
[Means for Solving the Problems]
The wheel rolling bearing unit of the present invention has a first mounting flange for supporting the suspension device on the outer circumferential surface and a double row outer ring raceway on the inner circumferential surface, as in the conventional wheel rolling bearing unit described above. Each of the outer ring, a second mounting flange for supporting the wheel on one end portion of the outer peripheral surface in the axial direction , and a first inner ring raceway on the other end portion in the axial direction . and one inner ring member, an axial end portion and the fitting support portion for externally secured without play the first inner ring member, a second inner ring raceway in an axially intermediate portion outer peripheral surface is provided, the shaft A second inner ring member having the other end in the direction as a housing part serving as an outer ring of a constant velocity joint, and a plurality of rolling elements provided in a freely rotatable manner between each outer ring raceway and each inner ring raceway. Is provided. Among these, the first small-diameter portion in which the female spline groove is formed on the inner peripheral surface in the axial direction of the first inner ring member has the same diameter as that of the first small-diameter portion on the inner peripheral surface in the other axial end portion. The second small diameter portions which are cylindrical surfaces are provided concentrically with each other. Further, the outer peripheral surface of the fitting support portion is fitted with a first fitting surface portion having a male spline groove that engages with the female spline groove formed in the first small diameter portion, and the second small diameter portion. A second fitting surface portion that is a cylindrical surface to be joined is provided concentrically with each other.
In particular, in the rolling bearing unit for a wheel of the present invention, the end portion of the first fitting surface portion is plastically deformed radially outward to form a caulking portion. The first inner ring member is clamped from both sides in the axial direction by the caulking portion and a step portion provided on the outer peripheral surface of the second intermediate inner ring member in the axial direction . An inner ring member is fixed to the second inner ring member. Also, the radial center portion of the second inner ring member in the axial direction intermediate portion to one end of the second inner ring member, a recess that opens in the axial direction one end side, said first and inner surface of the recess It exists on the inner diameter side of the second fitting surface portion. At the same time, a part of the partition plate portion closing the space between the concave portion and the housing portion is overlapped with the second fitting surface portion in the radial direction. The male spline groove is formed up to the tip of the fitting support portion. Further, the fitting between the second small diameter portion and the second fitting surface portion is a fitting with a tightening margin, and when the first and second inner ring members are combined, the second The female spline groove and the male spline groove start to be engaged before the small diameter portion and the second fitting surface portion start to be engaged.
[0011]
[Action]
In the case of the rolling bearing unit for a wheel 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 margin. The bending rigidity can be made higher than the case, and the deformation of the wheel rolling bearing unit can be suppressed and the running stability of the automobile can be improved regardless of the large moment load applied during traveling. In addition, when the first and second inner ring members are combined, the female spline groove and the male spline groove are formed before the second small diameter portion and the second fitting surface portion start to be fitted. Since the restriction is made so as to start the engagement, the manufacturing cost can be reduced by facilitating the assembly work.
In addition, since the male spline groove is formed up to the tip of the fitting support portion and the axial length of the first fitting surface portion is increased, the second small diameter portion is a fitting with a tightening margin. The axial length of the fitting portion between the first fitting surface portion and the second fitting surface portion can be increased, and the bending rigidity with respect to the moment load can be further increased.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an example of a reference example related 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 to increase the bending rigidity with respect to the moment load of the rolling bearing unit for the wheel without complicating the assembling work. It is in the point which devised the structure of the fitting part with the joint support part 11a. Since the structure and operation of the other parts are almost the same as those of the conventional structure shown in FIG. 4 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted or simplified. The description will focus on the characteristic part and the part different from the conventional structure.
[0013]
A first small-diameter portion 9a in which a female spline groove 32a is formed on the inner peripheral surface in the axial direction of the cylindrical first inner ring member 4a constituting the hub 6a of the wheel rolling bearing unit of the present reference example, the other axial end portion in the peripheral surface (the right end in FIG. 1-2), is provided with a second small diameter portion 10a is a cylindrical surface of large diameter, concentric to each other than the first small-diameter portion 9a. On the other hand, one axial end portion (the left end portion in FIGS. 1 and 2) of the second inner ring member 5a that constitutes the hub 6a together with the first inner ring member 4a fits the first inner ring member 4a without rattling. It is set as the fitting support part 11a for fixing. A first fitting surface portion 16a having a male spline groove 33a that engages with the female spline groove 32a formed in the first small-diameter portion 9a is formed on the outer peripheral surface of the axially intermediate portion of the fitting support portion 11a. On the outer peripheral surface of the other axial end portion, a second fitting surface portion 17a that is a cylindrical surface that fits with the second small diameter portion 10a is provided concentrically with each other. Further, the fitting between the second small diameter portion 10a and the second fitting surface portion 17a is a fitting with a tightening margin. Further, the axial length L _16a of the first fitting surface portion 16a is longer than the axial length L _{10a of} the second small diameter portion 10a.
[0014]
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 as shown in FIG. When inserted, 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 start to be spline engaged. 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 so that the spline grooves 32a and 33a are engaged with each other. It can be done. In this way, after the end portions of both the 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 fittings having a tightening margin, are formed. Since the fitting starts, the second inner ring member 5a is further press-fitted into the first inner ring member 4a. And after making the external thread part 15 provided in the axial direction one end part of the said 2nd inner ring member 5a protrude from said 1st small diameter part 9a, as shown in FIG. The first and second inner ring members 4a and 5a are coupled to each other by screwing and further tightening. At the same time, the double-row outer ring raceways 3 and 3 provided on the inner peripheral surface of the outer ring 1 and the first and second inner ring raceways 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, 19, which are provided so as to be capable of rolling each in between.
[0015]
The operation of rotatably supporting the wheel with respect to the suspension device by the wheel rolling bearing unit of the present reference example configured as described above is the same as that of the conventional wheel rolling bearing unit described above. In particular, in the case of the present reference example, the fitting between the second small diameter portion 10a and the second fitting surface portion 17a is fitted with a tightening margin to increase the bending rigidity with respect to the moment load. Yes. 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 assembled with the wheel rolling bearing unit can be improved. Further, the axial length L _16a of the first mating surface 16a is made longer than the axial length L _10a of the second small-diameter portion 10a, the first, second inner ring member 4a, 5a A female spline groove 32a formed on the inner peripheral surface of the first small-diameter portion 9a prior to the second small-diameter portion 10a and the second fitting surface portion 17a starting to be fitted together. The spline engagement with the male spline groove 33a formed on the outer peripheral surface of the first fitting surface portion 16a is restricted so as to start. Therefore, the assembly operation of the hub 6a can be facilitated, and a rolling bearing unit for a wheel having high bending rigidity and excellent performance can be realized at low cost.
[0016]
In the illustrated example, a male spline groove 33a is formed over the entire length of the first fitting surface portion 16a. However, the female spline groove 32a formed on the inner peripheral surface of the first small-diameter portion 9a and the first first-portion before the second small-diameter portion 10a and the second fitting surface portion 17a start to be engaged. 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. There is no need. For example, the male spline groove 33a is formed only in the first half (the left half in FIGS. 1 and 2) of the first fitting surface 16a, and the base half (see FIGS. 1 and 2) of the first fitting surface 16a. The right half of 2) may be a cylindrical surface portion having a smaller diameter 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 portion where the cylindrical surface portion and the male spline groove 33a are formed is equal to 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 axial end portion (left end portion in FIG. 3) of the second inner ring member 5b constituting the hub 6b of the wheel rolling bearing unit of this example is a portion closer to one axial end portion. (the left side portion of FIG. 3), the first mating surface 16b formed with a male spline groove 33b to the tip (left end in FIG. 3), the other axial end portion (right end portion in FIG. 3), the cylindrical surface The second fitting surface portions 17b are provided concentrically with each other. When the fitting support portion 11b is inserted into the first inner ring member 4b 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 is inserted. 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 start to engage in spline. In this case, the first fitting surface portion 16b has a straight shape up to the tip. After that, since the second small diameter portion 10b and the second fitting surface portion 17b, which are fittings having a tightening margin, start to be fitted, the second inner ring member 5b is further connected to the first inner ring member. Press fit into 4b. Then, with the other end surface in the axial direction of the first inner ring member 4b (the right end surface in FIG. 3) abutting against the stepped portion 30 provided on the outer peripheral surface in the axial direction intermediate portion of the second inner ring member 5b, The front end portion of the first fitting surface portion 16b is plastically deformed outward in the diameter direction to form the caulking portion 31. In this state, the first inner ring member 4b is clamped 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. Note that the position of the stepped portion 30 and the like is regulated so that an appropriate preload is applied to the rolling elements 19 and 19 with the first inner ring member 4b abutting against the stepped portion 30. Further, a recess 34 that opens to one end side in the axial direction is formed in the axially middle portion or one end portion of the second inner ring member 5b at the radial center portion of the second inner ring member 5b . The back surface 35 is present on the inner diameter side of the second fitting surface portion 17b. At the same time, a part of the partition plate portion 22 that closes the space between the concave portion 34 and the housing portion 14 that is the outer ring of the constant velocity joint 13 is overlapped with the second fitting surface portion 17b in the radial direction.
[0018]
In the case of the wheel rolling bearing unit of the present example configured as described above, the weight and cost due to the reduction in the number of parts, as compared with the example of the reference example described above, because the nut 18 (see FIG. 1) is not used. Can be reduced. Further, a male spline groove 33b is formed up to the tip of the fitting support portion 11b, and the axial length of the first fitting surface portion 16b is increased. Accordingly, the axial length of the fitting portion between the second small diameter portion 10b and the second fitting surface portion 17b, which is a fitting with a tightening margin, can be increased, and the bending rigidity with respect to the moment load can be further increased. I can do it. Other structures and operations are the same as those in the case of the reference example described above.
[0019]
【The invention's effect】
Since the present invention is configured and operates as described above, it is possible to improve the performance of the wheel rolling bearing unit while suppressing an increase in manufacturing cost.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing an example of a reference example related to the present invention.
FIG. 2 is a partial cross-sectional view showing an assembly process.
FIG. 3 is a partial cross-sectional view showing an example of an embodiment of the present invention.
FIG. 4 is a partial sectional view showing an example of a conventional structure.
[Explanation of symbols]
Reference Signs List 1 outer ring 2 first mounting flange 3 outer ring raceway 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 raceway 9 , 9a, 9b First small diameter portion 10, 10a, 10b Second small diameter portion 11, 11a, 11b Fitting support portion 12 Second inner ring raceway 13 Constant velocity joint 14 Housing portion 15 Male thread portion 16, 16a, 16b First One fitting surface portion 17, 17a, 17b Second fitting surface portion 18 Nut 19 Rolling element 20a, 20b Cover 21a, 21b Seal ring 22 Separating plate portion 23 Inner ring 24 Cage 25 Ball 26 Inner engagement groove 27 Outer engagement Groove 28 Pocket 29 Locking groove 30 Step part 31 Caulking part 32, 32a, 32b Female spline groove 33, 33a, 33b Male spline groove 34 Recessed part 35 Back face

Claims

A first mounting flange for supporting the suspension system on an outer peripheral surface, the outer ring raceway of the double row inner circumferential surface, an outer ring having, respectively, a second for supporting a wheel in the axial direction near one end portion of the outer peripheral surface The cylindrical inner ring member provided with the first inner ring raceway on the other end portion in the axial direction and the cylindrical inner ring member respectively provided on the other end in the axial direction, and the first inner ring member on the one end in the axial direction are removed without rattling. and fitting support portion for fixedly fitted, and a second inner ring member having an axially intermediate portion provided a second inner ring raceway on an outer peripheral surface, a housing portion serving as the other axial end portion constant velocity joint outer ring, and A plurality of rolling elements provided between each of the outer ring raceways and each of the inner ring raceways, and a female spline groove is formed on the inner circumferential surface of the intermediate portion in the axial direction of the first inner ring member. a first small-diameter portion, similarly than the small diameter portion the first to the other axial end portion inner peripheral surface A second small diameter portion that is a cylindrical surface of a diameter is provided concentrically with each other, and an outer peripheral surface of the fitting support portion is formed with a male spline groove that engages with a female spline groove formed in the first small diameter portion. In the rolling bearing unit for a wheel, in which the first fitting surface portion and the second fitting surface portion that is a cylindrical surface that is fitted to the second small diameter portion are provided concentrically with each other, The tip portion of one fitting surface portion is plastically deformed radially outward to form a caulking portion, and the caulking portion and the step portion provided on the outer peripheral surface in the axial direction intermediate portion of the second inner ring member, The first inner ring member is fixed to the second inner ring member by clamping a part of the first inner ring member from both sides in the axial direction, and the axially intermediate portion of the second inner ring member. to the radial center portion of the second inner ring member at one end, a recess that opens in the axial direction one end side The inner surface of the recess with the presence on the inner diameter side of the second mating surface, a portion of the diaphragm portion which closes the space between the recess and the housing portion, the second mating surface and radially The male spline groove is formed up to the tip of the fitting support portion, and the fitting between the second small diameter portion and the second fitting surface portion is tightly fitted. And, when the first and second inner ring members are combined, the female spline groove and the male spline before the second small diameter portion and the second fitting surface portion start to be fitted together. Rolling bearing unit for wheels, characterized by starting to engage with the groove.