JP4239669B2

JP4239669B2 - Rolling bearing unit for wheel support

Info

Publication number: JP4239669B2
Application number: JP2003129765A
Authority: JP
Inventors: 雄二中村
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 2003-05-08
Filing date: 2003-05-08
Publication date: 2009-03-18
Anticipated expiration: 2023-05-08
Also published as: JP2004332831A

Description

【０００１】
【発明の属する技術分野】
この発明に係る車輪支持用転がり軸受ユニットは、自動車の車輪を、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支持用転がり軸受ユニットが、各種使用されている。図５は、特許文献１に記載された車輪支持用転がり軸受ユニットの１例を示している。懸架装置を構成するナックル１に内嵌固定した状態で使用時に回転しない外輪２の内周面に、複列の外輪軌道３、３を設けている。１対の内輪４ａ、４ｂと組み合わされてハブ５を構成するハブ本体６の外周面の軸方向外端（軸方向に関して外とは、車体への組み付け状態で幅方向外側となる側で、各図の左側。本明細書全体で同じ。）寄り部分には車輪を支持する為の回転フランジ７を形成している。又、上記ハブ本体６の軸方向中間部乃至内端部（軸方向に関して内とは、車体への組み付け状態で幅方向内側となる側で、各図の右側。本明細書全体で同じ。）には、それぞれの外周面に内輪軌道８、８を形成した、上記１対の内輪４ａ、４ｂを外嵌している。これら両内輪４ａ、４ｂは、上記ハブ本体６の軸方向内端部を直径方向外方に折り曲げて成るかしめ部９により、このハブ本体６に支持固定している。又、上記各外輪軌道３、３と上記各内輪軌道８、８との間には、それぞれ複数個ずつの転動体１０、１０を設けて、上記外輪２の内側に上記ハブ５を、回転自在に支持している。
【０００３】
又、このハブ５の中心部には、スプライン孔１１を設けて、このハブ５と等速ジョイント１２とを組み合わせ自在としている。この等速ジョイント１２の一端部には、上記スプライン孔１１と係合するスプライン軸１３を設けている。又、上記等速ジョイント１２の内端部には、等速ジョイント用外輪として機能するハウジング部１４を設けている。このハウジング部１４の内径側には、図示しない等速ジョイント用内輪及び複数のボールを組み付ける。この様な等速ジョイント１２と上記ハブ５とは、上記スプライン孔１１に上記スプライン軸１３を挿入した状態に組み合わせ、上記両部材１２、５と凹凸係合した弾性材製の結合部材１５により、分離防止を図っている。更に、この結合部材１５に、磁性材製或は永久磁石製で円輪状又は円筒状のエンコーダ１６ａ、１６ｂを添設している。車体への組み付け状態では、前記ナックル１等の回転しない部分に支持した、図示しない回転検出センサの検出部を上記各エンコーダ１６ａ、１６ｂに対向させて、上記両部材１２、５の回転速度を検出する。特許文献１には、走行時に車輪が跳ね上げる飛び石等から上記各エンコーダ１６ａ、１６ｂを保護する構造に関しては、特に記載されていない。
【０００４】
これに対して、特許文献２には、図６に示す様に、永久磁石製で円輪状のエンコーダ１６ａの内側面を、シールリップ１７ａ、１７ｂを構成する弾性材により覆う構造が記載されている。この構造では、外輪２と内輪４との間の空間１８の軸方向内端開口部を塞ぐ組み合わせシールリング１９を構成するスリンガ２０を、金属板を曲げ形成する事により、断面略Ｔ字形で全体を円環状に形成している。そして、上記スリンガ２０の軸方向内側面に上記エンコーダ１６ａを、全周に亙って添着している。更にこのエンコーダ１６ａの軸方向内側面を、上記シールリップ１７ａ、１７ｂを構成する弾性材により覆っている。又、これら各シールリップ１７ａ、１７ｂにより、上記エンコーダ１６ａの外径側に存在する径方向隙間、上記内輪４の軸方向内端面と等速ジョイント１２のハウジング部１４の軸方向外端面との間に存在する軸方向隙間を塞いでいる。上記径方向隙間を塞ぐ事は、上記空間１８内への異物進入防止の為に重要であり、上記軸方向隙間を塞ぐ事は、かしめ部９及びこのかしめ部９の加工に伴って負荷された応力が残留している内輪４の一部への異物付着を防止し、このかしめ部９及びこの内輪４の一部に応力腐食割れが発生するのを防止する為に重要である。
【０００５】
又、何れも図示は省略するが、特許文献３〜５には、永久磁石製のエンコーダの軸方向内側面を、非磁性金属等の板材により覆う事で、このエンコーダを保護する構造が記載されている。又、特許文献６、７には、回転しない外輪と回転する等速ジョイントのハウジングとの間にラビリンスシール若しくは接触式のシールを設ける事により、かしめ部を形成した部分への異物進入防止を図る構造が記載されている。更に、特許文献８には、互いに同期して回転するハブと等速ジョイントのハウジングとの間に接触式のシールを設ける事により、かしめ部を形成した部分への異物進入防止を図る構造が記載されている。
【０００６】
【特許文献１】
米国特許５６７４０１１号明細書
【特許文献２】
米国特許出願公開第２００２／０１３１６５９号明細書
【特許文献３】
特開平１１−３０３８７９号公報
【特許文献４】
特開２００１−２４１４３５号公報
【特許文献５】
特開２００２−３３３０３３号公報
【特許文献６】
特開２００２−１７４２５６号公報
【特許文献７】
特開２００２−１９５２８０号公報
【特許文献８】
特開２０００−１４２００９号公報
【０００７】
【発明が解決しようとする課題】
車輪の回転速度検出を行なう為に永久磁石製のエンコーダを使用する事は、回転検出センサの小型、軽量化を図る面から好ましい。又、永久磁石としてゴム磁石を使用する事は、取付作業に伴って上記エンコーダに微小変形が生じてもこのエンコーダに割れ等の損傷が生じない構造を得られ、このエンコーダをハブ等の回転部材に圧入固定する作業の容易化が可能になるだけでなく、上記エンコーダの軽量化及び低廉化を図る面から好ましい。これに対して、特許文献１に記載された構造の場合、エンコーダ１６ａ、１６ｂを飛び石等から保護する構造を設けていない為、これら各エンコーダ１６ａ、１６ｂとして、低コストで造れるゴム磁石製のものを使用すると、信頼性確保の面から問題を生じる。
【０００８】
これに対して特許文献２に記載された構造の場合には、エンコーダ１６ａの表面を弾性材により覆っている為、多少は飛び石からのこのエンコーダ１６ａの保護を図れるが、十分とは言えない。即ち、軟らかい弾性材の薄膜により覆った程度では、上記エンコーダ１６ａの保護を十分に図る事は難しい。又、１個のスリンガ２０に、このエンコーダ１６ａとシールリップ１７ａ、１７ｂとを設けている為、このスリンガ２０の断面形状が複雑になる。この結果、このスリンガ２０のコストが嵩む他、形状精度を確保する事が難しくなる。
【０００９】
又、特許文献３〜５に記載された構造の場合には、ゴム磁石製のエンコーダの保護は図れても、ハブ本体の軸方向内端部に設けたかしめ部及びこのかしめ部の加工に伴って負荷された応力が残留している内輪の一部に、雨水等の異物が付着する事は防止できない。この為、ハブ本体に対し内輪を固定する為、このハブ本体の内端部にかしめ部を設けた構造に適用した場合に、このかしめ部及び上記内輪の一部が腐食する事に伴う、応力腐食割れの防止を図る事はできない。
【００１０】
又、特許文献６に記載された構造の場合には、洗車時に吹き付けられる洗浄水がかしめ部を設けた部分及び内輪の一部にまで入り込む事を十分に防止できないだけでなく、ゴム磁石製のエンコーダを保護する事に就いては考慮していない。更に、特許文献７に記載された構造の場合には、相対回転する外輪と等速ジョイントとの間を密封する構造である為、密封性能を確保する為には各部の形状精度並びに平滑度を高くする等、コストが嵩むだけでなく、シールリップの先端縁と相手面とが摩擦係合する為、回転トルクの増大により車両の性能を悪化させると言った問題もある。ゴム磁石製のエンコーダを保護する事に就いて考慮していない点に関しては、特許文献８に記載された構造も、上記特許文献６〜７に記載された構造と同様である。
本発明の車輪支持用転がり軸受ユニットは、上述の様な事情に鑑みて、ゴム磁石製のエンコーダの保護並びにかしめ部を設置した部分への異物の進入防止を有効に図れる構造を低コストで実現すべく発明したものである。
【００１１】
【課題を解決するための手段】
本発明の車輪支持用転がり軸受ユニットは、外輪と、ハブと、転動体と、組み合わせシールリングと、エンコーダとを備える。
このうちの外輪は、内周面に複列の外輪軌道を有し、使用時にも回転しない。
又、上記ハブは、ハブ本体に少なくとも１個の内輪を外嵌固定すると共に、このうちのハブ本体の軸方向内端部を径方向外方に塑性変形して成るかしめ部により上記内輪の軸方向内端面を抑え付けて、この内輪を上記ハブ本体に固定して成る。そして、外周面の軸方向外端寄り部分に車輪を支持する為の回転フランジを、同じく中間部乃至内端寄り部分に直接又は上記内輪を介して複列の内輪軌道を、それぞれ設けている。
又、上記転動体は、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ている。
又、上記組み合わせシールリングは、上記外輪の軸方向内端部内周面と上記ハブの軸方向内端部外周面との間に設けられたもので、シールリング素子とスリンガとを備える。このうちのシールリング素子は、上記外輪の軸方向内端部に固定した円環状の芯金、及び、この芯金に全周に亙って添設された弾性材製のシール材を備える。又、上記スリンガは、断面略Ｌ字形で全体が円環状の金属板製で、円筒部及びこの円筒部の端縁から径方向外方に折れ曲がった円輪部を備える。そしてこのスリンガは、上記円筒部を上記ハブの軸方向内端寄り部分の外周面で上記シールリングと対向する部分に外嵌固定された状態で、上記シール材に設けたシールリップを全周に亙り摺接させている。
又、前記エンコーダは、軸方向内側面にＳ極とＮ極とを交互に配置した永久磁石製で、上記円輪部の内側面に全周に亙って添着されている。
特に、本発明の車輪支持用転がり軸受ユニットに於いては、上記エンコーダの軸方向内側面に非磁性金属板製のカバーを、全周に亙って添着している。そして、このカバーの内周縁にその端縁を全周に亙って連続させた塞ぎ部材により、上記かしめ部及び内輪の内端部を外部空間から遮断している。
【００１２】
【作用】
上述の様に構成する本発明の車輪支持用転がり軸受ユニットの場合には、永久磁石製のエンコーダの軸方向内側面に非磁性金属板製で板状のカバーを、全周に亙って添着している為、上記エンコーダをゴム磁石により造った場合でも、このエンコーダが飛び石等により損傷を受ける事を有効に防止できる。又、上記カバーの内周縁にその端縁を全周に亙って連続させた塞ぎ部材により、ハブ本体の軸方向内端部に設けたかしめ部及び、このかしめ部の加工に伴って負荷された応力が残留している内輪の内端部で、シールリング素子により密封されていない部分を外部空間から遮断している為、これらかしめ部及び内輪の内端部に水分等の異物が付着してこのかしめ部及び内輪の内端部が腐食する事を防止できる。そして、このかしめ部及び内輪の内端部に応力腐食割れが発生する事を有効に防止できる。
【００１３】
【発明の実施の形態】
図１〜２は、請求項１〜３に対応する、本発明の実施の形態の第１例として、本発明を駆動輪（ＦＲ車及びＲＲ車の後輪、ＦＦ車の前輪、４ＷＤ車の全輪）を懸架装置に支持する為の車輪支持用転がり軸受ユニットに適用した場合に就いて示している。本例の車輪支持用転がり軸受ユニットは、外輪２ａと、ハブ５ａと、複数個の転動体１０、１０と、組み合わせシールリング１９ａと、エンコーダ１６ａとを備える。
このうちの外輪２ａは、外周面に固定フランジ２１を、内周面に複列の外輪軌道３、３を、それぞれ有する。この様な外輪２ａは、自動車への組み付け状態で、上記固定フランジ２１をナックル１（図５参照）に対し、複数本のボルトにより結合固定する。従って上記外輪２ａは、使用時にも回転しない。
【００１４】
又、上記ハブ５ａは、ハブ本体６ａと１個の内輪４とを不離に組み合わせて成る。このうちのハブ本体６ａは、中心部にスプライン孔１１ａを有する中空筒状である。この様なハブ本体６ａの外周面のうち、軸方向外寄り部分には車輪を結合固定する為の回転フランジ７ａを、中間部には内輪軌道８を、軸方向内寄り部分には小径段部２２を、それぞれ形成している。この小径段部２２には、外周面に内輪軌道８を形成した上記内輪４を外嵌している。そして、上記ハブ本体６ａの軸方向内端部でこの内輪４よりも軸方向内方に突出した円筒状部分を径方向外方に塑性変形させて成るかしめ部９ａにより、上記内輪４の軸方向内端面を抑え付けている。この様にして、外周面に複列の内輪軌道８、８を有する、上記ハブ５ａを構成している。前記各転動体１０、１０は、上記各外輪軌道３、３と上記各内輪軌道８、８との間にそれぞれ複数個ずつ、保持器２３、２３に保持された状態で、転動自在に設けられている。
【００１５】
又、前記組み合わせシールリング１９ａは、上記外輪２ａの軸方向内端部内周面と、上記ハブ５ａの軸方向内端部外周面との間に設けられて、上記各転動体１０、１０を設置した空間１８ａの、軸方向内端側開口部を塞いでいる。そして、外部空間（車輪支持用転がり軸受ユニットの周囲に存在し、何ら他の部分と隔てられていない空間）に浮遊する雨水や塵芥等の異物が上記空間１８ａ内に入り込む事を防止すると共に、この空間１８ａ内に存在するグリースが上記外部空間に漏れ出す事を防止する。この様な組み合わせシールリング１９ａは、シールリング素子２４とスリンガ２０ａとを備える。
【００１６】
このうちのシールリング素子２４は、芯金２５によりシール材２６を補強して成る。この芯金２５は、ＳＵＳ３０４の如きステンレス鋼板等の金属板にプレスによる打ち抜き加工及び曲げ加工を施す事により、断面略Ｌ字形で全体を円環状に形成したもので、外径側円筒部２７と、この外径側円筒部２７の軸方向外端縁から径方向内方に折れ曲がった内側円輪部２８とを備える。又、上記シール材２６は、ゴムの如きエラストマー等の弾性材製で、３本のシールリップ２９ａ、２９ｂ、２９ｃを備える。この様なシール材２６の基部は上記芯金２５に、焼き付き、接着等により、全周に亙り結合固定されている。この様なシールリング素子２４は、上記外径側円筒部２７を前記外輪２ａの軸方向内端部内周面に、締り嵌めで内嵌する事により、この外輪２ａに対し固定している。
【００１７】
又、上記スリンガ２０ａは、ＳＵＳ４３０の如きステンレス鋼板等の磁性金属板にプレスによる打ち抜き加工及び曲げ加工を施す事により、断面略Ｌ字形で全体を円環状に形成したもので、内径側円筒部３０と、この内径側円筒部３０の軸方向内端縁から径方向外方に折れ曲がった外側円輪部３１とを備える。この様なスリンガ２０ａは、上記内径側円筒部３０を前記内輪４の軸方向内端部外周面に、締り嵌めで外嵌する事により、この内輪４を含む、前記ハブ５ａに対し固定している。又、この状態で上記スリンガ２０ａを構成する上記内径側円筒部３０の外周面、並びに、上記外側円輪部３１の軸方向外側面に、上記各シールリップ２９ａ、２９ｂ、２９ｃの先端縁を、それぞれ全周に亙り摺接させている。
【００１８】
又、前記エンコーダ１６ａは、ゴム中にフェライト等の磁性粉末を混入したゴム磁石で、全体を円輪状に形成すると共に、軸方向に着磁している。着磁方向は、円周方向に亙って交互に且つ等間隔で変化させており、被検出面である上記エンコーダ１６ａの軸方向内側面にはＳ極とＮ極とを、交互に且つ等間隔で配置している。この様なエンコーダ１６ａは、上記スリンガ２０ａを構成する外側円輪部３１の軸方向内側面に、接着或は焼き付け（加硫固着）により、全周に亙って添着されている。
【００１９】
更に、上記エンコーダ１６ａの軸方向内側面に板状のカバー３２を、全周に亙って、接着、焼き付け等により添着している。このカバー３２は、厚さが０．２〜０．４mm程度である、ＳＵＳ３０４等の非磁性金属薄板にプレスによる打ち抜き加工及び曲げ加工を施す事により、全体を円輪状に形成している。即ち、上記カバー３２は、円輪部３３の外周縁部を軸方向外方に直角に折り曲げて外径側折れ曲がり部３４を、内周縁部を軸方向内方に９０度よりも小さく折り曲げて内径側折れ曲がり部３５を、それぞれ形成している。このうちの外径側折れ曲がり部３４の内径は、上記エンコーダ１６ａの外径とほぼ一致させている。従って上記カバー３２はこのエンコーダ１６ａに、同心に結合されている。又、上記内径側折れ曲がり部３５の基端部の直径（この内径側折れ曲がり部３５の外径）は、前記内輪４の軸方向内端面の外径よりも小さくしている。そして、上記スリンガ２０ａをこの内輪４の内端部に外嵌固定した状態で、上記円輪部３３の軸方向外側面の内径寄り部分を、上記内輪４の軸方向内端面の外径寄り部分に、全周に亙って当接させている。
【００２０】
又、上記内径側折れ曲がり部３５には、第二シール材３６の基端部を、この内径側折れ曲がり部３５の全周に亙って、モールド時のインサート、接着、焼き付け等により結合している。上記第二シール材３６は、ほぼ円筒状に形成されており、自由状態でこの第二シール材３６の先端縁（軸方向内端縁）が、前記かしめ部９ａの軸方向内端面よりも、軸方向内方に突出する様にしている。又、上記第二シール材３６の先端縁部の直径は、上記かしめ部９ａの外径よりも大きく、前記ハブ５ａと組み合わされる等速ジョイント１２ａのハウジング部１４ａの外端面のうちで、上記第二シール材３６の先端縁部が対向する部分の外径よりも小さくしている。
【００２１】
上述の様な本例の車輪支持用転がり軸受ユニットを自動車の懸架装置に組み付けた状態では、前記スプライン孔１１ａに上記等速ジョイント１２ａに付属のスプライン軸１３ａを、軸方向内側から外側に向け挿通する。そして、このスプライン軸１３ａの先端部（軸方向外端部）で上記ハブ５ａの軸方向外端面から突出した部分に形成された雄ねじ部にナット３７を螺合し更に緊締する。この結果、上記ハブ５ａが、このナット３７と上記ハウジング部１４ａとの間で軸方向両側から挟持されて、上記等速ジョイント１２ａと車輪支持用転がり軸受ユニットとが結合固定される。又、この状態では、上記第二シール材３６の先端縁が上記ハウジング部１４ａの軸方向外端面に当接して、この第二シール材３６の軸方向長さが、弾性的に縮められる。この結果第二シール材３６の先端縁が上記ハウジング部１４ａの軸方向外端面に、全周に亙って十分な面圧で押し付けられ、前記かしめ部９ａを外部空間から遮断する。更に、前記エンコーダ１６ａの軸方向内側面には、前記ナックル１等の固定の部分に支持された回転検出センサ３８の検出部を、前記カバー３２を介して対向させる。この結果、上記エンコーダ１６ａを固定したハブ５ａ、延いてはこのハブ５ａに支持固定した車輪の回転速度を検出自在になる。
【００２２】
上述の様に本例の車輪支持用転がり軸受ユニットの場合には、ゴム磁石製のエンコーダ１６ａの軸方向内側面に非磁性金属板製で板状の上記カバー３２を、全周に亙って添着している為、上記エンコーダ１６ａが飛び石等により損傷を受ける事を有効に防止できる。又、上記カバー３２にその基端縁を全周に亙って連続させ、その先端縁を上記ハウジング部１４ａの軸方向外端面に全周に亙って突き当てた第二シール材３６により、前記ハブ本体６ａの軸方向内端部に設けたかしめ部９ａ及び、このかしめ部９ａの加工に伴って負荷された応力が残留している前記内輪４の内端部で、前記シールリング素子２４により密封されていない部分を外部空間から遮断している為、これらかしめ部９ａ及び内輪４の内端部に水分等の異物が付着してこれらかしめ部９ａ及び内輪４の内端部が腐食する事を防止できる。そして、このかしめ部９ａ及び内輪４の内端部に応力腐食割れが発生する事を有効に防止できる。
【００２３】
次に、図３〜４は、請求項１、４〜６に対応する、本発明の実施の形態の第２例として、本発明を従動輪（ＦＲ車及びＲＲ車の前輪、ＦＦ車の後輪）を懸架装置に支持する為の車輪支持用転がり軸受ユニットに適用した場合に就いて示している。従って、本例の車輪支持用転がり軸受ユニットは、等速ジョイントとは組み合わされない。これに伴って本例のハブ５ｂを構成するハブ本体６ｂは、スプライン孔を持たない、中実体としている。１対の内輪軌道８、８はそれぞれ、このハブ本体６ｂの中間部乃至内端寄り部分に外嵌した１対の内輪４ａ、４ｂの外周面に形成している。
【００２４】
又、本例の場合も、外輪２ｂの軸方向内端部内周面と、上記ハブ５ｂの軸方向内端部外周面との間に組み合わせシールリング１９ａを設けて、各転動体１０、１０を設置した空間１８ａの、軸方向内端側開口部を塞いでいる。又、上記組み合わせシールリング１９ａを構成するスリンガ２０ａの外側円輪部３１の軸方向内側面にエンコーダ１６ａを、全周に亙って添設している。上記シールリング１９ａ及びエンコーダ１６ａの基本的な構造に就いては、前述した第１例の場合と同様であるから、重複する説明は省略する。
【００２５】
特に、本例の場合には、上記エンコーダ１６ａの軸方向内側面を覆う円輪状のカバー３２ａと一体に、有底円筒状（シャーレ状）の覆板部３９を設けている。即ち、本例の場合には、ＳＵＳ３０４の如きステンレス鋼板等の非磁性金属板に絞り加工を施す事により、上記カバー３２ａと上記覆板部３９とを一体に形成している。このうちの覆板部３９は、円板状の底板部４０と、この底板部４０の外周縁から軸方向外方に折れ曲がった第二円筒部４１とから成るもので、この第二円筒部４１の軸方向外端縁と上記カバー３２ａの内周縁とが連続している。又、上記第二円筒部４１の内径は、かしめ部９ｂの外径及び次述する段部４２の外径よりも大きくしている。更に、上記第二円筒部４１の深さは、次述する段差面４３から上記かしめ部９ｂの軸方向内端面までの軸方向距離以上としている。
【００２６】
前記１対の内輪４ａ、４ｂのうち、軸方向内側に位置し、上記かしめ部９ｂにより軸方向内端面を抑え付けられた内輪４ｂの軸方向内端部外周面に、スリンガ２０ａの内径側円筒部３０を外嵌する肩部４４よりも小径の段部４２を形成している。上記第二円筒部４１の内径は、この段部４２の外径よりも大きく、且つ、上記肩部４４の外径よりも小さくしている。そして、上記スリンガ２０ａを上記内輪４ｂに組み付けるべく、上記内径側円筒部３０を上記肩部４４に外嵌固定した状態で、上記カバー３２ａの軸方向外側面内径寄り部分を、この肩部４４と上記段部４２とを連続させる段差面４３に当接させている。上記スリンガ２０ａを構成する外側円輪部３１の軸方向内側面に添設した、前記エンコーダ１６ａの軸方向位置は、この状態で適正になる様に、各部の寸法を規制している。尚、上記第二円筒部４１は、必ずしも直径が軸方向に亙って同じである必要はない。軸方向に亙って直径が変化するテーパ状若しくは曲面状のものも、上記第二円筒部４１となり得る。
【００２７】
上述の様に構成する本例の構造の場合、前記覆板部３９が、上記かしめ部９ｂ全体、及び、上記内輪４ｂの内端部で前記シールリング素子２４により密封されていない部分を覆い、外部空間に存在する雨水や塵芥等の異物が、これらかしめ部９ｂ及び内輪４ｂの内端部に付着し、これらかしめ部９ｂ及び内輪４ｂの内端部を腐食させる事を防止する。従って、本例の場合も、これらかしめ部９ｂ及び内輪４ｂの内端部に応力腐食割れが生じ、これらかしめ部９ｂ及び内輪４ｂの内端部の強度が低下する事を防止する。
尚、本例の場合も、上記カバー３２ａがゴム磁石製のエンコーダ１６ａの軸方向内側面を覆う為、このエンコーダ１６ａが飛び石等により損傷を受ける事を有効に防止できる。
【００２８】
更に、本例の場合も、上記エンコーダ１６ａの軸方向内側面には、前記ナックル１等の固定の部分に支持された回転検出センサ３８の検出部を、上記カバー３２ａを介して対向させる。この結果、上記エンコーダ１６ａを固定したハブ５ｂ、延いてはこのハブ５ｂに支持固定した車輪の回転速度を検出自在になる。本例の場合、上記内輪４ｂの軸方向内端部外周面に上記段部４２を形成する事により、車輪支持用転がり軸受ユニットのうちで上記回転検出センサ３８を設置する部分の外径を小さくしている。そして、この回転検出センサ３８の先端面を、前記肩部４４の外周面よりも径方向内方に位置させている。この構成により、上記回転検出センサ３８として、前述した第１例に使用するものと同種のものを使用可能とし、部品の共通化に基づくコスト低減を可能にしている。
【００２９】
【発明の効果】
本発明の車輪支持用転がり軸受ユニットは、以上に述べた通り構成され作用するので、ゴム磁石製のエンコーダの保護並びにかしめ部を設置した部分への異物の進入防止を有効に図れる構造を低コストで実現できる。
【図面の簡単な説明】
【図１】本発明の実施の形態の第１例を示す半部断面図。
【図２】図１のＡ部拡大図。
【図３】本発明の実施の形態の第２例を示す断面図。
【図４】図２のＢ部拡大図。
【図５】従来構造の第１例を示す半部断面図。
【図６】同第２例を示す部分断面図。
【符号の説明】
１ナックル
２、２ａ、２ｂ外輪
３外輪軌道
４、４ａ、４ｂ内輪
５、５ａ、５ｂハブ
６、６ａ、６ｂハブ本体
７、７ａ回転フランジ
８内輪軌道
９、９ａ、９ｂかしめ部
１０転動体
１１、１１ａスプライン孔
１２、１２ａ等速ジョイント
１３、１３ａスプライン軸
１４、１４ａハウジング部
１５結合部材
１６ａ、１６ｂエンコーダ
１７ａ、１７ｂシールリップ
１８、１８ａ空間
１９、１９ａ組み合わせシールリング
２０、２０ａスリンガ
２１固定フランジ
２２小径段部
２３保持器
２４シールリング素子
２５芯金
２６シール材
２７外径側円筒部
２８内側円輪部
２９ａ、２９ｂ、２９ｃシールリップ
３０内径側円筒部
３１外側円輪部
３２、３２ａカバー
３３円輪部
３４外径側折れ曲がり部
３５内径側折れ曲がり部
３６第二シール材
３７ナット
３８回転検出センサ
３９覆板部
４０底板部
４１第二円筒部
４２段部
４３段差面
４４肩部[0001]
BACKGROUND OF THE INVENTION
The wheel-supporting rolling bearing unit according to the present invention is used for rotatably supporting a vehicle wheel with respect to a suspension device.
[0002]
[Prior art]
In order to support the wheel rotatably with respect to the suspension device, various types of wheel bearing rolling bearing units in which an outer ring and an inner ring are rotatably combined via rolling elements are used. FIG. 5 shows an example of a wheel support rolling bearing unit described in Patent Document 1. Double-row outer ring raceways 3 and 3 are provided on the inner peripheral surface of the outer ring 2 that does not rotate in use while being fitted and fixed to the knuckle 1 that constitutes the suspension device. The outer peripheral surface of the hub body 6 constituting the hub 5 in combination with the pair of inner rings 4a and 4b is the outer end in the axial direction (the outer side in the axial direction is the outer side in the width direction when assembled to the vehicle body. The left side of the figure (the same applies to the entire specification)) A rotating flange 7 for supporting the wheel is formed on the side portion. Further, the hub body 6 has an axially intermediate portion or an inner end portion (the inner side in the axial direction is the inner side in the width direction when assembled to the vehicle body, the right side in each drawing. The same applies throughout the present specification). Are fitted with the above-mentioned pair of inner rings 4a, 4b, which have inner ring raceways 8, 8 formed on their outer peripheral surfaces. These inner rings 4a and 4b are supported and fixed to the hub body 6 by caulking portions 9 formed by bending the axially inner end of the hub body 6 outward in the diameter direction. Further, a plurality of rolling elements 10 and 10 are provided between the outer ring raceways 3 and 3 and the inner ring raceways 8 and 8, respectively, and the hub 5 is rotatable inside the outer ring 2. I support it.
[0003]
A spline hole 11 is provided in the center of the hub 5 so that the hub 5 and the constant velocity joint 12 can be combined freely. A spline shaft 13 that engages with the spline hole 11 is provided at one end of the constant velocity joint 12. A housing portion 14 that functions as an outer ring for a constant velocity joint is provided at the inner end of the constant velocity joint 12. A constant velocity joint inner ring and a plurality of balls (not shown) are assembled to the inner diameter side of the housing portion 14. Such a constant velocity joint 12 and the hub 5 are combined in a state where the spline shaft 13 is inserted into the spline hole 11, and by a coupling member 15 made of an elastic material engaged with the both members 12 and 5, We are trying to prevent separation. Further, the coupling member 15 is provided with encoders 16a and 16b made of a magnetic material or a permanent magnet and having an annular shape or a cylindrical shape. In the assembled state to the vehicle body, the rotation speed of the both members 12 and 5 is detected by making a detection unit of a rotation detection sensor (not shown) supported by a non-rotating portion such as the knuckle 1 facing the encoders 16a and 16b. To do. Patent Document 1 does not particularly describe a structure for protecting each of the encoders 16a and 16b from a stepping stone or the like that a wheel jumps during traveling.
[0004]
On the other hand, Patent Document 2 describes a structure in which an inner surface of an annular encoder 16a made of a permanent magnet is covered with an elastic material constituting seal lips 17a and 17b, as shown in FIG. . In this structure, the slinger 20 constituting the combined seal ring 19 that closes the axially inner end opening of the space 18 between the outer ring 2 and the inner ring 4 is bent and formed by bending a metal plate so that the entire sealer 19 has a substantially T-shaped cross section. Is formed in an annular shape. The encoder 16a is attached to the inner side surface in the axial direction of the slinger 20 over the entire circumference. Further, the inner surface of the encoder 16a in the axial direction is covered with an elastic material constituting the seal lips 17a and 17b. Further, by these seal lips 17a and 17b, the radial gap existing on the outer diameter side of the encoder 16a, the space between the inner end surface of the inner ring 4 in the axial direction and the outer end surface of the constant velocity joint 12 in the axial direction. The axial gap that exists in Closing the radial gap is important for preventing foreign matter from entering the space 18, and closing the axial gap was loaded in connection with the caulking portion 9 and the caulking portion 9. This is important in order to prevent foreign matter from adhering to a part of the inner ring 4 where the stress remains, and to prevent the occurrence of stress corrosion cracking in the caulking portion 9 and a part of the inner ring 4.
[0005]
Although not shown in any of the drawings, Patent Documents 3 to 5 describe structures for protecting the encoder by covering the inner surface in the axial direction of the encoder made of a permanent magnet with a plate material such as a non-magnetic metal. ing. In Patent Documents 6 and 7, a labyrinth seal or a contact-type seal is provided between the outer ring that does not rotate and the housing of the rotating constant velocity joint, thereby preventing foreign matter from entering the caulked portion. The structure is described. Furthermore, Patent Document 8 describes a structure that prevents foreign matter from entering a portion where a caulking portion is formed by providing a contact-type seal between a hub that rotates in synchronization with each other and a housing of a constant velocity joint. Has been.
[0006]
[Patent Document 1]
US Pat. No. 5,674,011
[Patent Document 2]
US Patent Application Publication No. 2002/0131659
[Patent Document 3]
Japanese Patent Laid-Open No. 11-303879
[Patent Document 4]
JP 2001-241435 A
[Patent Document 5]
JP 2002-333033 A
[Patent Document 6]
JP 2002-174256 A
[Patent Document 7]
JP 2002-195280 A
[Patent Document 8]
JP 2000-142009
[0007]
[Problems to be solved by the invention]
It is preferable to use an encoder made of a permanent magnet to detect the rotational speed of the wheel from the viewpoint of reducing the size and weight of the rotation detection sensor. In addition, the use of a rubber magnet as a permanent magnet provides a structure that does not cause damage such as cracking of the encoder even if the encoder is slightly deformed during the mounting operation. In addition to facilitating the press-fitting and fixing operation, it is preferable from the viewpoint of reducing the weight and cost of the encoder. On the other hand, since the structure described in Patent Document 1 does not have a structure for protecting the encoders 16a and 16b from a stepping stone or the like, these encoders 16a and 16b are made of rubber magnets that can be manufactured at low cost. Use of this causes a problem in terms of ensuring reliability.
[0008]
On the other hand, in the case of the structure described in Patent Document 2, since the surface of the encoder 16a is covered with an elastic material, the encoder 16a can be somewhat protected from stepping stones, but it is not sufficient. That is, it is difficult to sufficiently protect the encoder 16a as long as it is covered with a soft elastic thin film. Further, since the encoder 16a and the seal lips 17a and 17b are provided in one slinger 20, the cross-sectional shape of the slinger 20 becomes complicated. As a result, the cost of the slinger 20 is increased and it is difficult to ensure the shape accuracy.
[0009]
In the case of the structures described in Patent Documents 3 to 5, even if the rubber magnet encoder can be protected, the caulking portion provided at the axially inner end of the hub main body and the processing of the caulking portion are accompanied. Therefore, it is impossible to prevent foreign matter such as rainwater from adhering to a part of the inner ring where the loaded stress remains. For this reason, in order to fix the inner ring to the hub body, when applied to a structure in which a caulking portion is provided at the inner end of the hub body, the stress caused by corrosion of the caulking portion and a part of the inner ring. It is impossible to prevent corrosion cracking.
[0010]
In addition, in the case of the structure described in Patent Document 6, it is not only possible to sufficiently prevent the washing water sprayed during car washing from entering the caulking portion and part of the inner ring, but also made of a rubber magnet. It doesn't consider protecting the encoder. Furthermore, in the case of the structure described in Patent Document 7, since the structure is such that the space between the outer ring and the constant velocity joint that rotate relative to each other is sealed, in order to ensure the sealing performance, the shape accuracy and smoothness of each part are increased. In addition to increasing the cost, such as increasing the height, there is also a problem that the performance of the vehicle deteriorates due to an increase in rotational torque because the tip edge of the seal lip and the mating surface are frictionally engaged. The structure described in Patent Document 8 is the same as the structures described in Patent Documents 6 to 7 in terms of not considering the protection of the rubber magnet encoder.
The rolling bearing unit for supporting a wheel of the present invention realizes a structure that can effectively prevent foreign magnets from entering a part where a rubber magnet encoder is protected and a caulking part is installed in view of the above-described circumstances. Invented as much as possible.
[0011]
[Means for Solving the Problems]
The wheel bearing rolling bearing unit of the present invention includes an outer ring, a hub, a rolling element, a combination seal ring, and an encoder.
Among these, the outer ring has a double row outer ring raceway on the inner peripheral surface, and does not rotate during use.
In the hub, at least one inner ring is externally fitted and fixed to the hub body, and the inner ring shaft is formed by a caulking portion formed by plastically deforming the axially inner end of the hub body radially outward. The inner ring is fixed to the hub body with the inner end face in the direction held down. A rotating flange for supporting the wheel is provided on the outer peripheral surface near the outer end in the axial direction, and a double row inner ring raceway is provided on the intermediate or inner end portion directly or via the inner ring.
A plurality of rolling elements are provided between the outer ring raceways and the inner ring raceways so as to roll freely.
The combined seal ring is provided between the inner circumferential surface of the inner end portion in the axial direction of the outer ring and the outer circumferential surface of the inner end portion in the axial direction of the hub, and includes a seal ring element and a slinger. Of these, the seal ring element includes an annular metal core fixed to the inner end in the axial direction of the outer ring, and an elastic seal material attached to the metal core over the entire circumference. The slinger is made of a metal plate having an approximately L-shaped cross section and an annular shape as a whole, and includes a cylindrical portion and an annular portion that is bent radially outward from an edge of the cylindrical portion. The slinger has a sealing lip provided on the sealing material on the entire circumference in a state where the cylindrical portion is externally fitted and fixed to a portion facing the seal ring on the outer peripheral surface near the inner end in the axial direction of the hub. It is in contact with slid.
The encoder is made of a permanent magnet having S poles and N poles alternately arranged on the inner side surface in the axial direction, and is attached to the inner side surface of the ring portion over the entire circumference.
In particular, in the rolling bearing unit for supporting a wheel according to the present invention, a cover made of a non-magnetic metal plate is attached to the entire inner circumference of the encoder in the axial direction. And the said caulking part and the inner edge part of an inner ring | wheel are interrupted | blocked from the outer space by the closing member which made the edge to the inner periphery of this cover continue over the perimeter.
[0012]
[Action]
In the case of the rolling bearing unit for supporting a wheel of the present invention configured as described above, a plate-like cover made of a non-magnetic metal plate is attached to the entire inner circumference of the inner surface in the axial direction of the encoder made of a permanent magnet. Therefore, even when the encoder is made of a rubber magnet, the encoder can be effectively prevented from being damaged by a stepping stone or the like. Further, a clogging member provided at the inner end in the axial direction of the hub body and a load applied along with the processing of the caulking portion by the closing member having the edge continuously connected to the inner peripheral edge of the cover over the entire circumference. Since the inner end of the inner ring where the residual stress remains is not sealed off from the external space by the seal ring element, foreign matter such as moisture adheres to these caulked parts and the inner end of the inner ring. It is possible to prevent the caulking portion of the lever and the inner end portion of the inner ring from corroding. And it can prevent effectively that a stress corrosion crack generate | occur | produces in this crimping part and the inner edge part of an inner ring | wheel.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1 to 3, in which the present invention is applied to driving wheels (rear wheels of FR and RR vehicles, front wheels of FF vehicles, 4WD vehicles). This shows a case where the present invention is applied to a wheel bearing rolling bearing unit for supporting all wheels) on a suspension device. The wheel support rolling bearing unit of this example includes an outer ring 2a, a hub 5a, a plurality of rolling elements 10, 10, a combination seal ring 19a, and an encoder 16a.
Of these, the outer ring 2a has a fixed flange 21 on the outer peripheral surface and double row outer ring raceways 3 and 3 on the inner peripheral surface. In such an outer ring 2a, the fixing flange 21 is coupled and fixed to the knuckle 1 (see FIG. 5) with a plurality of bolts in an assembled state to the automobile. Therefore, the outer ring 2a does not rotate during use.
[0014]
The hub 5a is formed by combining the hub body 6a and one inner ring 4 without separation. Of these, the hub body 6a has a hollow cylindrical shape having a spline hole 11a at the center. Of such an outer peripheral surface of the hub main body 6a, a rotating flange 7a for coupling and fixing a wheel is provided at an axially outer portion, an inner ring raceway 8 is provided at an intermediate portion, and a small diameter step portion is provided at an axially inner portion. 22 are formed. The inner ring 4 having the inner ring raceway 8 formed on the outer peripheral surface is externally fitted to the small diameter step portion 22. An axial direction of the inner ring 4 is formed by a caulking portion 9a formed by plastically deforming a cylindrical portion protruding inward in the axial direction from the inner ring 4 at an inner end in the axial direction of the hub body 6a. The inner end face is held down. In this way, the hub 5a having the double-row inner ring raceways 8 and 8 on the outer peripheral surface is constituted. Each of the rolling elements 10 and 10 is provided between the outer ring raceways 3 and 3 and the inner ring raceways 8 and 8 so as to be freely rollable while being held by the cages 23 and 23. It has been.
[0015]
The combined seal ring 19a is provided between the inner peripheral surface of the inner end portion in the axial direction of the outer ring 2a and the outer peripheral surface of the inner end portion in the axial direction of the hub 5a. The opening in the axial direction inner end side of the space 18a is closed. And, while preventing foreign matters such as rainwater and dust floating in the external space (the space around the wheel bearing rolling bearing unit and not separated from any other part) from entering the space 18a, The grease existing in the space 18a is prevented from leaking into the external space. Such a combination seal ring 19a includes a seal ring element 24 and a slinger 20a.
[0016]
Among these, the seal ring element 24 is formed by reinforcing a seal material 26 with a core metal 25. The metal core 25 is formed by punching and bending a metal plate such as a stainless steel plate such as SUS304 with a press to form an overall annular shape with a substantially L-shaped cross section. And an inner ring portion 28 that is bent radially inward from the axial outer end edge of the outer diameter side cylindrical portion 27. The sealing material 26 is made of an elastic material such as an elastomer such as rubber, and includes three sealing lips 29a, 29b, and 29c. The base portion of such a sealing material 26 is coupled and fixed to the core metal 25 over the entire circumference by seizing, bonding or the like. Such a seal ring element 24 is fixed to the outer ring 2a by fitting the outer diameter side cylindrical part 27 to the inner peripheral surface of the inner end of the outer ring 2a in the axial direction by an interference fit.
[0017]
The slinger 20a is formed by punching and bending a magnetic metal plate such as a stainless steel plate such as SUS430 by a press to form an overall annular shape with a substantially L-shaped cross section. And an outer ring portion 31 that is bent radially outward from the inner end edge in the axial direction of the inner diameter side cylindrical portion 30. Such a slinger 20a is fixed to the hub 5a including the inner ring 4 by fitting the inner diameter side cylindrical portion 30 to the outer peripheral surface of the inner ring 4 in the axial direction inner end portion by an interference fit. Yes. Further, in this state, on the outer peripheral surface of the inner diameter side cylindrical portion 30 constituting the slinger 20a and on the outer surface in the axial direction of the outer ring portion 31, the end edges of the seal lips 29a, 29b, 29c are provided. Each is in contact with the entire circumference.
[0018]
The encoder 16a is a rubber magnet in which magnetic powder such as ferrite is mixed in rubber. The encoder 16a is formed in an annular shape and is magnetized in the axial direction. The magnetization direction is changed alternately at equal intervals over the circumferential direction, and S poles and N poles are alternately and equally provided on the inner surface in the axial direction of the encoder 16a, which is the detected surface. Arranged at intervals. Such an encoder 16a is attached to the entire inner circumference of the outer ring portion 31 constituting the slinger 20a over the entire circumference by bonding or baking (vulcanization fixation).
[0019]
Further, a plate-like cover 32 is attached to the inner side surface in the axial direction of the encoder 16a by bonding, baking or the like over the entire circumference. The cover 32 is formed in an annular shape by punching and bending a nonmagnetic metal thin plate such as SUS304 having a thickness of about 0.2 to 0.4 mm by a press. That is, the cover 32 is formed by bending the outer peripheral edge portion of the annular ring portion 33 at right angles outward in the axial direction to bend the outer diameter side bent portion 34 and bending the inner peripheral edge portion axially inward to be smaller than 90 degrees. Side bent portions 35 are respectively formed. Of these, the inner diameter of the outer-diameter-side bent portion 34 is substantially matched with the outer diameter of the encoder 16a. Therefore, the cover 32 is concentrically coupled to the encoder 16a. Further, the diameter of the proximal end portion of the inner diameter side bent portion 35 (the outer diameter of the inner diameter side bent portion 35) is made smaller than the outer diameter of the inner end surface in the axial direction of the inner ring 4. Then, in a state where the slinger 20a is externally fitted and fixed to the inner end portion of the inner ring 4, a portion closer to the inner diameter of the outer circumferential surface of the circular ring portion 33 is a portion closer to the outer diameter of the inner end surface of the inner ring 4 in the axial direction. In addition, they are in contact over the entire circumference.
[0020]
Further, the base end portion of the second seal material 36 is joined to the inner diameter side bent portion 35 over the entire circumference of the inner diameter side bent portion 35 by insert, bonding, baking, or the like at the time of molding. . The second sealing material 36 is formed in a substantially cylindrical shape, and the distal end edge (axial inner end edge) of the second sealing material 36 in a free state is more than the axial inner end face of the caulking portion 9a. It protrudes inward in the axial direction. The diameter of the tip edge portion of the second seal member 36 is larger than the outer diameter of the caulking portion 9a, and among the outer end surfaces of the housing portion 14a of the constant velocity joint 12a combined with the hub 5a, The front end edge of the two sealing material 36 is made smaller than the outer diameter of the facing part.
[0021]
In the state where the wheel support rolling bearing unit of the present example as described above is assembled to the suspension device of the automobile, the spline shaft 13a attached to the constant velocity joint 12a is inserted into the spline hole 11a from the inner side to the outer side in the axial direction. To do. Then, a nut 37 is screwed into a male screw portion formed in a portion protruding from the axially outer end surface of the hub 5a at the tip end portion (axially outer end portion) of the spline shaft 13a, and further tightened. As a result, the hub 5a is sandwiched between the nut 37 and the housing part 14a from both sides in the axial direction, and the constant velocity joint 12a and the wheel support rolling bearing unit are coupled and fixed. In this state, the tip end edge of the second seal member 36 abuts on the axial outer end surface of the housing portion 14a, and the axial length of the second seal member 36 is elastically shortened. As a result, the front end edge of the second seal member 36 is pressed against the outer end surface in the axial direction of the housing portion 14a with a sufficient surface pressure over the entire circumference, thereby blocking the caulking portion 9a from the external space. Further, the detection portion of the rotation detection sensor 38 supported by a fixed portion such as the knuckle 1 is opposed to the inner side surface in the axial direction of the encoder 16 a via the cover 32. As a result, the rotational speed of the hub 5a to which the encoder 16a is fixed, and thus the wheel supported and fixed to the hub 5a can be detected.
[0022]
As described above, in the case of the wheel bearing rolling bearing unit of this example, the plate-like cover 32 made of a nonmagnetic metal plate is provided on the entire inner circumference of the inner side surface in the axial direction of the encoder 16a made of rubber magnet. Since it is attached, it is possible to effectively prevent the encoder 16a from being damaged by a stepping stone or the like. Further, a second seal member 36 is formed by allowing the base edge of the cover 32 to be continuous over the entire circumference, and the tip edge of the cover 32 to abut against the outer circumferential surface of the housing portion 14a over the entire circumference. The seal ring element 24 is formed at a caulking portion 9a provided at an inner end portion in the axial direction of the hub body 6a, and at an inner end portion of the inner ring 4 where a stress applied by the processing of the caulking portion 9a remains. Since the portion that is not sealed by the outer space is blocked from the external space, foreign matters such as moisture adhere to the caulking portion 9a and the inner end of the inner ring 4, and the caulking portion 9a and the inner end of the inner ring 4 are corroded. You can prevent things. And it can prevent effectively that the stress corrosion crack generate | occur | produces in this crimping part 9a and the inner edge part of the inner ring | wheel 4.
[0023]
Next, FIGS. 3 to 4 show the present invention as a second example of the embodiment of the present invention corresponding to claims 1, 4 to 6, and driven wheels (front wheels of FR and RR vehicles, rear of FF vehicles). It shows a case where the present invention is applied to a wheel bearing rolling bearing unit for supporting a wheel) on a suspension device. Therefore, the wheel bearing rolling bearing unit of this example is not combined with the constant velocity joint. Accordingly, the hub body 6b constituting the hub 5b of this example is a solid body having no spline hole. The pair of inner ring raceways 8 and 8 are respectively formed on the outer peripheral surfaces of the pair of inner rings 4a and 4b that are externally fitted to the intermediate portion or the inner end portion of the hub body 6b.
[0024]
Also in the case of this example, a combination seal ring 19a is provided between the inner circumferential surface of the inner end of the outer ring 2b in the axial direction and the outer circumferential surface of the inner end of the hub 5b in the axial direction. The axial direction inner end side opening of the installed space 18a is closed. In addition, an encoder 16a is provided along the entire circumference on the inner surface in the axial direction of the outer ring portion 31 of the slinger 20a constituting the combination seal ring 19a. The basic structure of the seal ring 19a and the encoder 16a is the same as in the case of the first example described above.
[0025]
In particular, in the case of this example, a bottomed cylindrical (petriform) cover plate portion 39 is provided integrally with an annular cover 32a that covers the inner surface in the axial direction of the encoder 16a. That is, in the case of this example, the cover 32a and the cover plate portion 39 are integrally formed by drawing a nonmagnetic metal plate such as a stainless steel plate such as SUS304. The cover plate portion 39 includes a disc-shaped bottom plate portion 40 and a second cylindrical portion 41 bent outward from the outer peripheral edge of the bottom plate portion 40 in the axial direction. The outer edge in the axial direction and the inner peripheral edge of the cover 32a are continuous. The inner diameter of the second cylindrical portion 41 is larger than the outer diameter of the caulking portion 9b and the outer diameter of the step portion 42 described below. Further, the depth of the second cylindrical portion 41 is equal to or greater than the axial distance from the step surface 43 described below to the inner end surface in the axial direction of the caulking portion 9b.
[0026]
Of the pair of inner rings 4a and 4b, the inner diameter side cylinder of the slinger 20a is positioned on the outer peripheral surface of the inner ring 4b which is positioned on the inner side in the axial direction and the inner end surface of the inner ring 4b is suppressed by the caulking portion 9b. A step portion 42 having a smaller diameter than the shoulder portion 44 to which the portion 30 is externally fitted is formed. The inner diameter of the second cylindrical portion 41 is larger than the outer diameter of the step portion 42 and smaller than the outer diameter of the shoulder portion 44. Then, in order to assemble the slinger 20a to the inner ring 4b, a portion of the cover 32a closer to the inner diameter of the outer surface in the axial direction is fitted with the shoulder portion 44 in a state where the inner diameter side cylindrical portion 30 is fitted and fixed to the shoulder portion 44. The stepped portion 42 is in contact with a stepped surface 43 that is continuous with the stepped portion 42. The dimension of each part is regulated so that the axial position of the encoder 16a attached to the inner side surface in the axial direction of the outer ring part 31 constituting the slinger 20a is appropriate in this state. The second cylindrical portion 41 does not necessarily have the same diameter in the axial direction. A tapered or curved surface whose diameter changes in the axial direction can also be the second cylindrical portion 41.
[0027]
In the case of the structure of the present example configured as described above, the cover plate portion 39 covers the entire caulking portion 9b and the portion not sealed by the seal ring element 24 at the inner end portion of the inner ring 4b. Foreign matter such as rain water and dust existing in the external space adheres to the inner end portions of the caulking portion 9b and the inner ring 4b, and prevents the caulking portion 9b and the inner end portion of the inner ring 4b from being corroded. Therefore, also in the case of this example, stress corrosion cracking occurs at the inner end portions of the caulking portion 9b and the inner ring 4b, thereby preventing the strength of the inner end portions of the caulking portion 9b and the inner ring 4b from being lowered.
Also in this example, since the cover 32a covers the inner surface in the axial direction of the encoder 16a made of rubber magnet, it is possible to effectively prevent the encoder 16a from being damaged by a stepping stone or the like.
[0028]
Furthermore, also in this example, the detection part of the rotation detection sensor 38 supported by the fixed part such as the knuckle 1 is opposed to the inner side surface in the axial direction of the encoder 16a via the cover 32a. As a result, the rotational speed of the hub 5b to which the encoder 16a is fixed, and thus the wheel supported and fixed to the hub 5b, can be detected. In the case of this example, the step 42 is formed on the outer peripheral surface of the inner ring 4b in the axial direction, thereby reducing the outer diameter of the portion where the rotation detection sensor 38 is installed in the wheel bearing rolling bearing unit. is doing. The distal end surface of the rotation detection sensor 38 is positioned radially inward from the outer peripheral surface of the shoulder portion 44. With this configuration, the rotation detection sensor 38 can be the same type as that used in the first example described above, and cost reduction based on common parts can be achieved.
[0029]
【The invention's effect】
Since the rolling bearing unit for supporting a wheel of the present invention is configured and operates as described above, it is possible to reduce the cost of a structure capable of effectively protecting a rubber magnet encoder and preventing foreign matters from entering a portion where a caulking portion is installed. Can be realized.
[Brief description of the drawings]
FIG. 1 is a half sectional view showing a first example of an embodiment of the present invention.
FIG. 2 is an enlarged view of a portion A in FIG.
FIG. 3 is a sectional view showing a second example of the embodiment of the present invention.
4 is an enlarged view of a portion B in FIG.
FIG. 5 is a half sectional view showing a first example of a conventional structure.
FIG. 6 is a partial sectional view showing the second example.
[Explanation of symbols]
1 knuckle
2, 2a, 2b Outer ring
3 Outer ring raceway
4, 4a, 4b Inner ring
5, 5a, 5b hub
6, 6a, 6b Hub body
7, 7a Rotating flange
8 Inner ring raceway
9, 9a, 9b Caulking part
10 Rolling elements
11, 11a Spline hole
12, 12a Constant velocity joint
13, 13a Spline shaft
14, 14a Housing part
15 coupling member
16a, 16b encoder
17a, 17b Seal lip
18, 18a space
19, 19a Combination seal ring
20, 20a Slinger
21 Fixed flange
22 Small diameter step
23 Cage
24 Seal ring element
25 cored bar
26 Sealing material
27 Outer diameter side cylindrical part
28 Inner ring part
29a, 29b, 29c Seal lip
30 Inner diameter side cylindrical part
31 Outer ring part
32, 32a cover
33 Annulus
34 Bending part of outer diameter side
35 Inner side bent part
36 Second sealant
37 nuts
38 Rotation detection sensor
39 Cover plate
40 Bottom plate
41 Second cylindrical part
42 steps
43 Stepped surface
44 shoulder

Claims

A double row outer ring raceway on the inner peripheral surface, and an outer ring that does not rotate during use, and at least one inner ring is fitted and fixed to the hub body, and the axially inner end of the hub body is radially An inner end surface in the axial direction of the inner ring is held down by a caulking portion formed by plastic deformation outward, and the inner ring is fixed to the hub body, and the wheel is supported on a portion of the outer peripheral surface near the outer end in the axial direction. A plurality of rotating flanges are also provided between the hub, each outer ring raceway, and each inner ring raceway, each of which has a double row of inner ring raceways directly or via the inner ring at the intermediate portion or inner end portion. A rolling element provided so as to be freely rollable, a combined seal ring provided between an inner circumferential surface of the inner end portion in the axial direction of the outer ring and an outer peripheral surface of the inner end portion in the axial direction of the hub, and an attachment to the combined seal ring. With this encoder. The mating seal ring includes an annular cored bar fixed to the inner end of the outer ring in the axial direction and a seal ring element provided with a sealing material made of an elastic material attached to the cored bar over the entire circumference; A cylindrical part and an annular part bent radially outward from the edge of the cylindrical part made of a metal plate having a substantially L-shaped cross section and entirely annular, and the cylindrical part of which is an inner end in the axial direction of the hub A slinger having a seal lip provided on the seal material in sliding contact with the entire circumference in a state of being fitted and fixed to a portion facing the seal ring on the outer peripheral surface of the side portion, and the encoder is A wheel-supporting rolling bearing unit made of a permanent magnet in which S poles and N poles are alternately arranged on the inner side surface in the axial direction and attached to the inner side surface of the ring portion over the entire circumference. However, a non-magnetic metal plate cassette is provided on the inner surface in the axial direction of the encoder. Is attached over the entire circumference, and the caulking portion is cut off from the external space by a closing member that is connected to the inner peripheral edge of the cover over the entire circumference. Rolling bearing unit for wheel support.

The spline shaft attached to the constant velocity joint is in spline engagement with the spline hole formed in the center of the hub, and the housing portion of the constant velocity joint is in contact with or opposed to the caulking portion. The second seal material made of an elastic material having the base end portion joined to the inner peripheral edge of the ring-shaped cover over the entire circumference, and the leading edge of the second seal material is part of the housing portion, The rolling bearing unit for wheel support according to claim 1, which is in contact with the entire circumference.

A bent portion that is bent inward in the axial direction is formed at the inner peripheral edge of the cover, and the base end portion of the second seal material is coupled to the bent portion over the entire circumference. The rolling bearing unit for supporting a wheel according to claim 2, wherein the front end edge is in contact with the outer end surface in the axial direction of the housing portion.

The wheel support rolling bearing unit is not combined with a constant velocity joint, and the closing member is a cover plate portion that is formed integrally with an annular cover and covers the entire inner diameter side of the cover. The wheel support rolling bearing unit described.

The cover plate portion is composed of a disc-shaped bottom plate portion and a second cylindrical portion bent axially outward from the outer peripheral edge of the bottom plate portion, and the axial outer edge of the second cylindrical portion and The rolling bearing unit for wheel support according to claim 4, wherein the inner peripheral edge of the cover is continuous.

On the outer peripheral surface of the inner ring in the axial direction, the inner end surface of the inner ring being held down by the caulking portion, a step portion having a smaller diameter than the shoulder that fits the cylindrical portion of the slinger is formed. The inner diameter is larger than the outer diameter of the step portion and smaller than the outer diameter of the shoulder portion, and the portion close to the inner diameter in the axial direction outer surface of the cover in a state where the cylindrical portion of the slinger is fitted and fixed to the shoulder portion. The wheel bearing rolling bearing unit according to claim 5, wherein the shoulder portion and the stepped portion are in contact with a stepped surface that is continuous.