JP2004084763A

JP2004084763A - Bearing for drive wheel

Info

Publication number: JP2004084763A
Application number: JP2002245488A
Authority: JP
Inventors: Hideji Tajima; 田島　英児; Hitohiro Ozawa; 小澤　仁博
Original assignee: NTN Corp; NTN Toyo Bearing Co Ltd
Current assignee: NTN Corp
Priority date: 2002-08-26
Filing date: 2002-08-26
Publication date: 2004-03-18

Abstract

<P>PROBLEM TO BE SOLVED: To prolong the service life of a bearing for a drive wheel by preventing ingress of foreign matters in the bearing. <P>SOLUTION: A bearing for a drive wheel comprises: an outer member 1 having double raceway surfaces 1a on an inner circumference; a hub wheel 2 having a raceway surface 2a facing on one raceway surface 1a of the outer member 1 and a wheel fitting flange 2b; an outside joint member 3b of a constant velocity universal joint 3 having a raceway surface 3a facing the other raceway surface 1a of the outer member 1 on the outer circumferential surface thereof; and double rolling elements 4 interposed between the raceway surface 1a of the outer member 1, the hub wheel 2, and the raceway surface 3a of the outside joint member 3b. Foreign matters intrusion preventive means 11, 12, 13, 14 and 15 are provided on the outer circumferential side of a butted part of the hub wheel and the equal velocity universal joint. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車等において車輪を車体に対して回転自在に支持するための車輪用軸受に関するもので、より詳しくはハブ輪と複列の軸受及び等速自在継手とをユニット化した駆動車輪用軸受に関するものである。
【０００２】
【従来の技術】
自動車の駆動車輪用軸受のうちハブ輪と複列の軸受及び等速自在継手とをユニット化した形式は、図４に示すように内周に複列の軌道面１ａを有する外方部材１と、アウトボード側の軌道面１ａに対向する軌道面２ａを有するハブ輪２と、インボート側の軌道面１ａに対向する軌道面３ａを有する等速自在継手３と、軌道面１ａと軌道面２ａ、３ａとの間に介在する複列の転動体４とを有している。
ここで、車両に組付けた状態で車両の外側寄りとなる側をアウトボード側といい（各図において図面左側）、車両の中央寄りになる側をインボード側という（各図において図面右側）。
ハブ輪２には車輪取付フランジ２ｂが設けられ、この車輪取付フランジ２ｂに車輪ホイール固定用のハブボルト６を用いて図示しない車輪が取付けられている。一方、外方部材１の外周１ｂには図示されない車体側の固定部（ナックルなど）に取付けるための取付フランジ１ｄが設けられている。この取付フランジ１ｄには取付け孔１ｅが設けられ、図示しないボルトにより固定部に固定され、車輪用軸受が車体に取付けられる。
【０００３】
駆動車輪用軸受においては、ハブ輪２が等速自在継手３の外側継手部材３ｂに結合される。外側継手部材３ｂは、椀状のマウス部３ｂｌと中実のステム部３ｂ２とからなり、ステム部３ｂ２にてハブ輪３とセレーション嵌合している。ステム部３ｂ２の軸端をかしめ固定することにより、ハブ輪２の端面２ｃが外側継手部材３ｂの肩部３ｂ４端面に押付けられ、ハブ輪２が軸方向で位置決めされると共に、転動体４に予圧が付与される。複列の転動体４はそれぞれ接触角を有しており、前述の予圧によって軸受剛性を高めるとともに、モーメント荷重を受けられる構造になっている。
【０００４】
【特許文献１】
特開平１１−７８４０８号公報
【特許文献２】
特開平１１−６２９５１号公報
【特許文献３】
特開２００１−１８６０５号公報
【特許文献４】
特開２００１−２３３００５号公報
【０００５】
【発明が解決しようとする課題】
上述のように、複列の転動体４には予圧が付与されていて車輪からの曲げモーメント荷重を受けられるようになっているが、自動車の速度及び旋回角度などによっては通常より大きな曲げモーメントが発生した場合、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４との突き合わせ面が微小変位することがある。このような微小変位があると、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４にフレッティングが発生する。フレッティングは摩耗粉を発生させ、この摩耗粉が軸受内部に入り込むと軸受寿命低下の原因となる。
【０００６】
また、ステム部３ｂ２の軸端をかしめ固定することにより、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４端面との間に軸力を発生させて、トルク負荷時においても両者間が相対回転しないようになっているが、自動車の急発進時などの急激に大きなトルクが発生した場合は、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４との突き合わせ面が微小変位（相対回転）し、フレッティングが発生させるとともに摩耗粉を発生させ、軸受寿命低下の原因となる。
【０００７】
そこで、本願の目的は、自動車の急旋回時などに発生する大きな曲げモーメントや急発進時などの大きなトルクが発生した場合、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４との突き合わせ面から摩耗粉が発生しても軸受内部にこの摩耗粉が入り込まず、長寿命な駆動車輪用軸受を提供することである。
【０００８】
【課題を解決するための手段】
この発明の請求項１記載の駆動車輪用軸受は、内周に複列の軌道面を有する外方部材と、外方部材の一方の軌道面に対向する軌道面と車輪取付フランジとを有するハブ輪と、外方部材の他方の軌道面に対向する軌道面を外周面に有する等速自在継手の外側継手部材と、外方部材の軌道面とハブ輪及び外側継手部材の各軌道面との間に介在する複列の転動体とで構成され、ハブ輪と等速自在継手の突き合わせ部の外周側に、突き合せ部から軸受内部空間（両端のシールで密封された空間）への異物侵入を防止する異物侵入防止手段を設けたものである。
これにより、ハブ輪の端面と外側継手部材の肩部との突き合わせ面から摩耗粉が発生しても軸受内部にこの摩耗粉が入り込まないので、軸受寿命低下せず長寿命になる。
【０００９】
この発明の請求項２記載の駆動車輪用軸受は、上記等速自在継手外輪がマウス部とステム部を有し、ステム部外周にハブ輪を嵌合したものである。
【００１０】
この発明の請求項３記載の駆動車輪用軸受は、上記等速自在継手外輪がマウス部とステム部を有し、ハブ輪のインボード側外周に前記ステム部を嵌合したものである。
【００１１】
この発明の請求項４記載の駆動車輪用軸受は、上記異物侵入防止手段がＯリングであるものである。
【００１２】
この発明の請求項５記載の駆動車輪用軸受は、上記異物侵入防止手段をグリースの塗布により形成したものである。グリースを塗布した場合、突き合せ部から発生する摩耗分をグリースが保持することにより、軸受内部に侵入することが防止できる。
【００１３】
この発明の請求項６記載の駆動車輪用軸受は、上記異物侵入防止手段が嫌気性接着剤である。接着剤であるため、突き合せ部外周に塗布しておくだけで硬化してシールとなるので、取り扱いに有利である。
【００１４】
この発明の請求項７記載の駆動車輪用軸受は、上記ハブ輪および等速自在継手外輪のうち、内径側の部材を拡径方向に塑性変形させたものである。このため、軽量化、コンパクト化が図れる。
【００１５】
【発明の実施の形態】
以下、図面に例示した本発明の実施形態を説明する。まず、図１は駆動車輪用軸受の第一の実施形態を示すもので、内周に複列の軌道面１ａを有する外方部材１と、アウトボード側の軌道面１ａに対向する軌道面２ａを有するハブ輪２と、インボート側の軌道面１ａに対向する軌道面３ａを有する等速自在継手３と、軌道面１ａと軌道面２ａ、３ａとの間に介在する複列の転動体４と、転動体４を円周方向等間隔に保持する保持器５とを有している。
ハブ輪２には車輪取付フランジ２ｂが設けられ、この車輪取付フランジ２ｂに車輪ホイール固定用のハブボルト６を用いて図示しない車輪が取付けられている。一方、外方部材１の外周１ｂには図示されない車体側の固定部（ナックルなど）に取付けるための取付フランジ１ｄが設けられている。この取付フランジ１ｄには取付け孔１ｅが設けられ、図示しないボルトにより固定部に固定され、車輪用軸受が車体に取付けられる。
【００１６】
駆動車輪用軸受においては、ハブ輪２が等速自在継手３の外側継手部材３ｂに結合される。外側継手部材３ｂは、椀状のマウス部３ｂｌと中空のステム部３ｂ２とからなり、ステム部３ｂ２の外周にハブ輪２を嵌合し、中空のステム部３ｂ２の内径側からステム部３ｂ２を拡径してかしめ結合（以下、拡径かしめと言う）されている。これにより、ハブ輪２の端面２ｃが外側継手部材３ｂの肩部３ｂ４端面に押付けられ、ハブ輪２が軸方向で位置決めされると共に、転動体４に予圧が付与される。複列の転動体４はそれぞれ接触角を有しており、前述の予圧によって軸受剛性を高めるとともに、モーメント荷重を受けられる構造になっている。
【００１７】
等速自在継手３は、図示しないドライブシャフトからのトルクを内側継手部材３ｃ及びトルク伝達ボール３ｄを介して外側継手部材３ｂへ伝達する。外側継手部材３ｂのステム部３ｂ２からハブ輪２との拡径かしめによって結合された部分を介してハブ輪２へ、さらに車輪取付フランジ２ｂ、ハブボルト６を介して図示しない車輪へトルクを伝達している。
【００１８】
等速自在継手３の外側継手部材３ｂは、鍛造による成形後、部分的に熱処理が施される。熱処理により硬化される部分は、図１に散点模様を付して表すように、肩部３ｂ４からインボード側の軌道面３ａを経てシール７Ｂのシールリップとの摺接面（シールランド）に至る領域と、マウス部３ｂ１内周のトルク伝達ボール３ｄが転動するトラック溝３ｂ３の領域とであり、何れもＨＲＣ５８以上となるまで硬化される。熱処理としては、局部加熱ができ、硬化層深さの選定が自由であり、かつ硬化層以外への熱影響が少なく母材の性能を保持できる高周波焼入れが適当である。
【００１９】
これ以外の部分、特にステム部３ｂ２のうち、後述する拡径かしめに際して外径側に塑性変形する部分（以下、被かしめ部３ｅと言う）には、鍛造後も熱処理が施されない。これら未熱処理部のうち、被かしめ部３ｅの硬度は拡径かしめ時の加工性を考えると低いほど好ましいが、低すぎる場合は疲労耐久性の低下を招く。したがって、被かしめ部３ｅはＨＲＣ１３以上２８以下、好ましくはＨＲＣ１８以上２５以下の硬度とするのが好ましい。
【００２０】
ハブ輪２内周の嵌合面のうち、外側継手部材３ｂの被かしめ部３ｅとの対向部分には凹凸部２ｄが形成される。嵌合面の凹凸部２ｄ以外の部分は、ステム部の円筒状外周面と密着嵌合する円筒状に形成されている。凹凸部２ｄの凹凸形状は任意であり、例えばねじ形状やセレーション（スプラインも含む）形状、あるいは互いに平行な複数列の溝同士を交差させたアヤメローレット形状に形成される。このようにして形成された凹凸部２ｄは、熱処理によってＨＲＣ５８以上まで硬化される。
【００２１】
熱処理による硬化層は、図１に散点模様で示すように、ハブ輪２内周の凹凸部２ｄの領域のみならず、ハブ輪２外周のシール７Ａのシールランドから軌道面２ａを経てインボード側の端面に至る領域にも形成される。これらの熱処理は、上記と同様の理由から高周波焼入れにより行うのが望ましい。なお、図示のようにハブ輪２の内径部と外径部の双方の硬化層を非連続とすることにより、ハブ輪２の焼き割れを生じにくくすることができる。
【００２２】
ハブ輪２と外側継手部材３ｂとは、拡径かしめにより一体に塑性結合される。すなわち、ハブ輪２の内周に外側継手部材３ｂのステム部３ｂ２を嵌合した状態で、ステム部３ｂ２の被かしめ部３ｅを内径側から外径側に塑性変形させ、被かしめ部３ｅの外周を凹凸部２ｄに食い込ませてハブ輪２と外側継手部３ｂとを塑性的に結合する。これにより、インナレース２ａ、３ａ間の寸法が規定されて軸受内部に所定の予圧が付与される。
【００２３】
かしめに際しては、上述のように凹凸部２ｄは高い硬度を備えるために潰れ難く、また、拡径側の被かしめ部３ｅは凹凸部２ｄに比べて低硬度で延性に富むために拡径代を大きくとってもステム部にかしめ割れが生じ難い。従って、凹凸部２ｄを被かしめ部３ｅに深く食い込ませることができ、これによりハブ輪２と外側継手部材３ｂとの間で高い結合強度が確保される。
【００２４】
かしめ加工は、例えば外側継手部材３ｂのステム部内周の貫通孔にかしめ治具（ポンチ）を挿入することによって行うことができる。つまり、外側継手部材３ｂのステム部をハブ輪２の内周に嵌合した後、ステム部の貫通孔の内径よりも大きな外径を備えたかしめ治具を貫通孔に押し込むことにより、ステム部の被かしめ部３ｅを内径側から外径側に拡径させる。
【００２５】
外側継手部材３ｂは、例えば合金元素として重量％でＣを０．５〜０．７％、Ｓｉを０．１〜１．５％、Ｍｎを０．６〜１．０％含有し、残部をＦｅおよび不可避的不純物とする鋼材で形成することができる。この中でもＳｉを０．６〜１．２％含有するものが好ましい。この他、ＪＩＳに規定する機械構造用炭素鋼のうち中炭素鋼、例えばＣを０．５〜０．６％、Ｓｉを０．１〜０．４％、Ｍｎを０．６〜１．０％を含むＳ５３Ｃ、あるいはＣを０．５〜０．６％、Ｓｉを０．７〜０．９％、Ｍｎを０．６〜１．０％を含む炭素鋼を使用することもできる。後者の鋼材は、Ｓｉの含有量が多い分、前者に比べて未熱処理部における疲労強度を高めることができる。
【００２６】
図２（ａ）〜（ｆ）は、図１のＡ部を拡大したもので、本件発明に係る異物侵入防止手段を示す。異物侵入防止手段は突き合せ部から軸受内部側へ異物の侵入を防止するもので、これは例えば、突き合せ部の隙間を外周側から密封することにより構成することができる。この密封手段としては、例えば突き合せ部の端面間の外周部近傍に介在物を介在させるもの（図２（ａ）、（ｄ）〜（ｆ）参照）、あるいは突き合せ部の外周を両部材に跨る形で被覆するもの（同図（ｂ）、（ｃ）参照）などが考えられる。具体的には以下の通りである。
【００２７】
図２（ａ）は本発明の第一の実施形態であり、ハブ輪２の端面２ｃが外側継手部材３ｂの肩部３ｂ４端面の突き合わせ部の外周側に、すなわちハブ輪２の端面２ｃ外周角部および外側継手部材３ｂの肩部３ｂ４外周角部にそれぞれ円周溝２ｃ１、３ｂ５を形成し、その突き合わせ部にＯリング１１を介在したものである。これにより自動車の急旋回時に発生する大きな曲げモーメントや急発進時の大きなトルクが発生した場合、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４との突き合わせ面から摩耗粉が発生しても、Ｏリング１１により軸受内部に摩耗粉の侵入を防止することができる。Ｏリング１１としては、例えば、ニトリルブタジエンゴム（ＮＢＲ）、シリコーンゴム、フッ素ゴム等を使用することができる。
【００２８】
図２（ｂ）は本発明の第二の実施形態であり、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４端面との突き合わせ部の外周側に、シール材１２を塗布したものである。シール材１２としては、例えば、スリーボンド１１０５、ロックタイト５９１０、信越化学ＦＥ１２３等を使用することができる。
【００２９】
図２（ｃ）は本発明の第三の実施形態であり、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４端面との突き合わせ部の外周側に、接着剤１３を塗布したものである。接着剤１３としては、種々の接着剤を使用することができ、例えば、合成ゴム系接着剤（スリーボンド１５２１等）を使用することができる。また、ハブ輪の端面２ｃと外側継手部材３ｂの肩部端面との間の外周部に嫌気性接着剤を介在させることもできる。
【００３０】
図２（ｄ）は本発明の第四の実施形態であり、ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４端面との突き合わせ部の外周側に、すなわちハブ輪２の端面２ｃ外周角部および外側継手部材３ｂの肩部３ｂ４外周角部にそれぞれ円周溝２ｃ１、３ｂ５を形成し、その突き合わせ部にグリース１４を介在したものである。グリース１４は軸受内部に封入するグリースと同じものが良い。同じグリースであれば軸受内部のグリースを劣化させることがない。したがって、軸受内部のグリースを劣化させるものでなければ良い。
【００３１】
図２（ｅ）は本発明の第五の実施形態であり、第四の実施例の変形例である。ハブ輪２の端面２ｃと外側継手部材３ｂの肩部３ｂ４端面との突き合わせ部の外周側に、すなわちハブ輪２の端面２ｃ外周角部および外側継手部材３ｂの肩部３ｂ４外周角部にそれぞれ円周溝２ｃ１、３ｂ５を形成し、その突き合わせ部にグリース１４を介在し、さらにグリース１４を軸受内部へ飛散しないように円筒部の板部材１５により突き合わせ部を塞いだものである。板部材１５はハブ輪２の外周面に圧入しており外側継手部材３ｂの外周面との間には隙間がある。次の図２（ｆ）は本発明の第六の実施形態であり、第五の実施形態の変形例である。図２（ｅ）に対し、板部材１５はハブ輪２の外周面に圧入するとともに、外側継手部材３ｂの外周面にも圧入している。板部材１５としては、例えばＳＰＣ、樹脂ＰＰ、ＰＡ６、ＰＡ６６等を使用することができる。
【００３２】
次に図３は、駆動車輪用軸受の他の実施形態を示すもので、内周に複列の軌道面１ａを有する外方部材１と、アウトボード側の軌道面１ａに対向する軌道面２ａを有するハブ輪２と、インボート側の軌道面１ａに対向する軌道面３ａを有する等速自在継手３と、軌道面１ａと軌道面２ａ、３ａとの間に介在する複列の転動体４と、転動体４を円周方向等間隔に保持する保持器５とを有している。
ハブ輪２には車輪取付フランジ２ｂが設けられ、この車輪取付フランジ２ｂに車輪ホイール固定用のハブボルト６を用いて図示しない車輪が取付けられている。一方、外方部材１の外周１ｂには図示されない車体側の固定部（ナックルなど）に取付けるための取付フランジ１ｄが設けられている。この取付フランジ１ｄには取付け孔１ｅが設けられ、図示しないボルトにより固定部に固定され、車輪用軸受が車体に取付けられる。
【００３３】
駆動車輪用軸受においては、ハブ輪２が等速自在継手３の外側継手部材３ｂに結合される。外側継手部材３ｂは、椀状のマウス部３ｂｌと中空のステム部３ｂ２とからなる。図１の実施形態と異なるのは、ステム部３ｂ２をハブ輪２の外周に嵌合し、中空のハブ輪２を内径側から拡径してかしめ結合（以下、拡径かしめと言う）している。これにより、外側継手部材３ｂの端面２ｃがハブ輪２の肩部３ｂ４端面に押付けられ、外側継手部材３ｂが軸方向で位置決めされると共に、転動体４に予圧が付与される。複列の転動体４はそれぞれ接触角を有しており、前述の予圧によって軸受剛性を高めるとともに、モーメント荷重を受けられる構造になっている。
【００３４】
この場合、かしめ加工の際に、軌道面３ａに影響を及ぼさないように軌道面３ａの軸方向においてインボード側の位置に該かしめ部３ｅを形成する必要がある。
【００３５】
図３に示す駆動車輪用軸受においても、第一の実施形態と同様に外側継手部材３ｂの端面２ｃとハブ輪２の肩部３ｂ４端面との突き合わせ部の外周に、図２（ａ）〜（ｆ）に示す異物侵入防止手段を設けている。
なお、図１、図３に示す８はキャップ部材である。ステム部３ｂ２（図１参照）及びハブ輪２（図２参照）が中空形状のため、等速自在継手の内部と外部が連通することになるので、異物侵入防止及びグリース漏れ防止のためにキャップ部材が必要となるものである。
【００３６】
【発明の効果】
以上のように本発明によれば、内周に複列の軌道面を有する外方部材と、外方部材の一方の軌道面に対向する軌道面と車輪取付フランジとを有するハブ輪と、外方部材の他方の軌道面に対向する軌道面を外周面に有する等速自在継手外輪と、外方部材の軌道面とハブ輪及び等速自在継手外輪の軌道面との間に介在する複列の転動体とで構成され、ハブ輪と等速自在継手の突き合わせ部の外周側に異物侵入防止手段を設けたものである。
これにより、ハブ輪と外側継手部材との突き合わせ面から摩耗粉が発生しても軸受内部にこの摩耗粉が入り込まないので、駆動車輪用軸受の長寿命化が図られることになる。
【図面の簡単な説明】
【図１】本発明に係る駆動車輪用軸受の一実施形態を示す縦断面図である。
【図２】（ａ）は図１のＡ部を拡大したもので、異物侵入防止手段の一例を示す縦断面図である、
（ｂ）は図１のＡ部を拡大したもので、異物侵入防止手段の他の例を示す縦断面図である、
（ｃ）は図１のＡ部を拡大したもので、異物侵入防止手段の他の例を示す縦断面図である、
（ｄ）は図１のＡ部を拡大したもので、異物侵入防止手段の他の例を示す縦断面図である、
（ｅ）は図１のＡ部を拡大したもので、異物侵入防止手段の他の例を示す縦断面図である、
（ｆ）は図１のＡ部を拡大したもので、異物侵入防止手段の他の例を示す縦断面図である。
【図３】本発明にかかる駆動車輪用軸受の他の実施形態を示す縦断面図である。
【図４】従来の駆動車輪用軸受の縦断面図である。
【符号の説明】
１　　　　　外方部材
１ａ　　　軌道面
２　　　　　　ハブ輪
３　　　　　　等速自在継手
３ｂ　　外側継手部材
３ｂ１　マウス部
４　　　　　　転動体
５　　　　　保持器
６　　　　　ハブボルト
７Ａ、７Ｂ　シール
８　　　キャップ部材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wheel bearing for rotatably supporting a wheel with respect to a vehicle body in an automobile or the like, and more particularly to a drive wheel in which a hub wheel, a double-row bearing and a constant velocity universal joint are unitized. It relates to bearings.
[0002]
[Prior art]
Among the bearings for driving wheels of an automobile, a type in which a hub wheel, a double-row bearing, and a constant velocity universal joint are unitized includes an outer member 1 having a double-row raceway surface 1a on an inner periphery as shown in FIG. A hub wheel 2 having a raceway surface 2a facing the outboard side raceway surface 1a, a constant velocity universal joint 3 having a raceway surface 3a facing the inboard side raceway surface 1a, the raceway surface 1a and the raceway surface 2a. , 3a and a double row of rolling elements 4 interposed therebetween.
Here, a side that is closer to the outside of the vehicle when assembled to the vehicle is called an outboard side (left side in each drawing), and a side closer to the center of the vehicle is called an inboard side (right side in each drawing). .
The hub wheel 2 is provided with a wheel mounting flange 2b, and a wheel (not shown) is mounted on the wheel mounting flange 2b using a hub bolt 6 for fixing a wheel. On the other hand, an outer periphery 1b of the outer member 1 is provided with a mounting flange 1d for mounting to a fixing portion (knuckle or the like) on the vehicle body (not shown). The mounting flange 1d is provided with a mounting hole 1e, which is fixed to a fixing portion by a bolt (not shown), and a wheel bearing is mounted on the vehicle body.
[0003]
In the drive wheel bearing, the hub wheel 2 is connected to the outer joint member 3 b of the constant velocity universal joint 3. The outer joint member 3b includes a bowl-shaped mouth portion 3bl and a solid stem portion 3b2, and the stem portion 3b2 is serrated with the hub wheel 3. By caulking and fixing the shaft end of the stem portion 3b2, the end surface 2c of the hub wheel 2 is pressed against the shoulder 3b4 end surface of the outer joint member 3b, whereby the hub wheel 2 is positioned in the axial direction and the rolling element 4 is preloaded. Is given. Each of the rolling elements 4 in the double row has a contact angle, and has a structure in which bearing rigidity is increased by the above-described preload and a moment load can be received.
[0004]
[Patent Document 1]
JP-A-11-78408 [Patent Document 2]
JP-A-11-62951 [Patent Document 3]
JP 2001-18605 A [Patent Document 4]
Japanese Patent Application Laid-Open No. 2001-233005
[Problems to be solved by the invention]
As described above, the pre-load is applied to the double row rolling elements 4 so that the bending moment load from the wheels can be received. If this occurs, the abutting surface between the end surface 2c of the hub wheel 2 and the shoulder 3b4 of the outer joint member 3b may be slightly displaced. If there is such a minute displacement, fretting occurs on the end face 2c of the hub wheel 2 and the shoulder 3b4 of the outer joint member 3b. Fretting generates abrasion powder, and if the abrasion powder enters the inside of the bearing, it causes a reduction in the life of the bearing.
[0006]
In addition, by caulking and fixing the shaft end of the stem portion 3b2, an axial force is generated between the end surface 2c of the hub wheel 2 and the end surface of the shoulder portion 3b4 of the outer joint member 3b, so that even when a torque is applied, the two members are in contact with each other. Although the relative rotation does not occur, when a sudden large torque is generated at the time of a sudden start of the vehicle or the like, the butt surface between the end surface 2c of the hub wheel 2 and the shoulder 3b4 of the outer joint member 3b has a small displacement ( (Relative rotation), fretting occurs, and wear powder is generated, which causes a reduction in bearing life.
[0007]
Accordingly, an object of the present application is to abut the end face 2c of the hub wheel 2 and the shoulder 3b4 of the outer joint member 3b when a large bending moment or a large torque is generated at the time of a sharp turn of the vehicle or at the time of a sudden start. An object of the present invention is to provide a long-life bearing for a drive wheel, in which even if wear powder is generated from the surface, the wear powder does not enter the inside of the bearing.
[0008]
[Means for Solving the Problems]
A drive wheel bearing according to claim 1 of the present invention is a hub having an outer member having a double-row raceway surface on an inner periphery, a raceway surface facing one raceway surface of the outer member, and a wheel mounting flange. A ring, an outer joint member of a constant velocity universal joint having an outer peripheral surface having a raceway surface facing the other raceway surface of the outer member, and a raceway surface of the outer member and each raceway surface of the hub wheel and the outer joint member. It is composed of a double row of rolling elements interposed therebetween, and foreign matter intrudes into the bearing internal space (space sealed by seals at both ends) from the butt portion to the outer peripheral side of the butt portion of the hub wheel and the constant velocity universal joint. Is provided with a foreign matter intrusion prevention means for preventing the intrusion.
As a result, even if abrasion powder is generated from the abutting surface of the end face of the hub wheel and the shoulder of the outer joint member, the abrasion powder does not enter the inside of the bearing.
[0009]
According to a second aspect of the present invention, in the bearing for a drive wheel, the outer race of the constant velocity universal joint has a mouth portion and a stem portion, and a hub wheel is fitted around the outer periphery of the stem portion.
[0010]
According to a third aspect of the present invention, in the bearing for a driving wheel, the outer race of the constant velocity universal joint has a mouth portion and a stem portion, and the stem portion is fitted to the outer periphery of the hub wheel on the inboard side.
[0011]
In the drive wheel bearing according to a fourth aspect of the present invention, the foreign matter intrusion prevention means is an O-ring.
[0012]
In the driving wheel bearing according to a fifth aspect of the present invention, the foreign matter intrusion preventing means is formed by applying grease. When grease is applied, the grease retains the abrasion generated from the butted portion, thereby preventing the grease from entering the bearing.
[0013]
In the drive wheel bearing according to claim 6 of the present invention, the foreign matter intrusion prevention means is an anaerobic adhesive. Since it is an adhesive, it is hardened to form a seal only by being applied to the outer periphery of the butted portion, which is advantageous in handling.
[0014]
A drive wheel bearing according to a seventh aspect of the present invention is one in which, of the hub wheel and the constant velocity universal joint outer ring, a member on the inner diameter side is plastically deformed in a diameter increasing direction. Therefore, the weight and the size can be reduced.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention illustrated in the drawings will be described. First, FIG. 1 shows a first embodiment of a drive wheel bearing, in which an outer member 1 having a double-row raceway surface 1a on an inner periphery and a raceway surface 2a facing the outboard raceway surface 1a. , A constant velocity universal joint 3 having a raceway surface 3a opposed to the raceway surface 1a on the inboard side, and a double row rolling element 4 interposed between the raceway surface 1a and the raceway surfaces 2a, 3a And a retainer 5 for holding the rolling elements 4 at equal intervals in the circumferential direction.
The hub wheel 2 is provided with a wheel mounting flange 2b, and a wheel (not shown) is mounted on the wheel mounting flange 2b using a hub bolt 6 for fixing a wheel. On the other hand, an outer periphery 1b of the outer member 1 is provided with a mounting flange 1d for mounting to a fixing portion (knuckle or the like) on the vehicle body (not shown). The mounting flange 1d is provided with a mounting hole 1e, which is fixed to a fixing portion by a bolt (not shown), and a wheel bearing is mounted on the vehicle body.
[0016]
In the drive wheel bearing, the hub wheel 2 is connected to the outer joint member 3 b of the constant velocity universal joint 3. The outer joint member 3b includes a bowl-shaped mouth portion 3bl and a hollow stem portion 3b2. The hub wheel 2 is fitted to the outer periphery of the stem portion 3b2, and the stem portion 3b2 is expanded from the inner diameter side of the hollow stem portion 3b2. The diameter is caulked and joined (hereinafter, referred to as diameter caulking). Thereby, the end face 2c of the hub wheel 2 is pressed against the end face of the shoulder 3b4 of the outer joint member 3b, whereby the hub wheel 2 is positioned in the axial direction, and a preload is applied to the rolling elements 4. Each of the rolling elements 4 in the double row has a contact angle, and has a structure in which bearing rigidity is increased by the above-described preload and a moment load can be received.
[0017]
The constant velocity universal joint 3 transmits torque from a drive shaft (not shown) to the outer joint member 3b via the inner joint member 3c and the torque transmitting ball 3d. Torque is transmitted from the stem portion 3b2 of the outer joint member 3b to the hub wheel 2 via a portion connected to the hub wheel 2 by expanding and caulking, and further to a wheel (not shown) via the wheel mounting flange 2b and the hub bolt 6. I have.
[0018]
The outer joint member 3b of the constant velocity universal joint 3 is partially heat-treated after being formed by forging. As shown in FIG. 1 by a dotted pattern, the part cured by the heat treatment is formed on the sliding contact surface (seal land) of the seal 7B with the seal lip through the inboard side raceway surface 3a from the shoulder 3b4. And the area of the track groove 3b3 where the torque transmitting ball 3d on the inner circumference of the mouth portion 3b1 rolls, and both are hardened until the HRC becomes 58 or more. As the heat treatment, induction hardening, which can perform local heating, can freely select the depth of the hardened layer, and has little heat influence on portions other than the hardened layer and can maintain the performance of the base material, is suitable.
[0019]
The other portions, especially the portion of the stem portion 3b2, which is plastically deformed to the outer diameter side at the time of the later-described radially expanded swaging (hereinafter, referred to as a swaged portion 3e), is not subjected to heat treatment even after forging. Among the unheated portions, the hardness of the portion to be caulked 3e is preferably as low as possible in view of the workability at the time of expanding and caulking. However, if it is too low, the fatigue durability is reduced. Therefore, the crimped portion 3e preferably has a hardness of HRC 13 or more and 28 or less, preferably HRC 18 or more and 25 or less.
[0020]
On the inner peripheral surface of the hub wheel 2, an uneven portion 2 d is formed at a portion of the outer joint member 3 b facing the swaged portion 3 e. The portion other than the concave-convex portion 2d of the fitting surface is formed in a cylindrical shape that is tightly fitted to the cylindrical outer peripheral surface of the stem portion. The concavo-convex shape of the concavo-convex portion 2d is arbitrary, and is formed, for example, in a screw shape, a serration (including spline) shape, or an iris knurled shape in which a plurality of parallel rows of grooves intersect. The uneven portion 2d thus formed is hardened to HRC 58 or more by heat treatment.
[0021]
As shown by the dotted pattern in FIG. 1, the hardened layer formed by the heat treatment is not limited to the area of the uneven portion 2d on the inner circumference of the hub wheel 2 but also from the seal land of the seal 7A on the outer circumference of the hub wheel 2 via the raceway surface 2a. It is also formed in a region reaching the side end surface. These heat treatments are desirably performed by induction hardening for the same reason as described above. By making the hardened layers of both the inner diameter portion and the outer diameter portion of the hub wheel 2 discontinuous as shown in the drawing, the hub wheel 2 can be hardly cracked.
[0022]
The hub wheel 2 and the outer joint member 3b are integrally plastically coupled by expanding and caulking. That is, with the stem portion 3b2 of the outer joint member 3b fitted to the inner periphery of the hub wheel 2, the swaged portion 3e of the stem portion 3b2 is plastically deformed from the inner diameter side to the outer diameter side, and the outer periphery of the swaged portion 3e Are cut into the uneven portion 2d to plastically couple the hub wheel 2 and the outer joint portion 3b. Thereby, the dimension between the inner races 2a, 3a is defined, and a predetermined preload is applied inside the bearing.
[0023]
At the time of caulking, as described above, the uneven portion 2d has a high hardness so that it is hard to be crushed, and the swaged portion 3e on the enlarged diameter side has a lower hardness and is more ductile than the uneven portion 2d, so that the diameter enlargement margin is increased. It is very unlikely that the stem will be caulked. Therefore, the uneven portion 2d can be deeply digged into the swaged portion 3e, whereby a high coupling strength is secured between the hub wheel 2 and the outer joint member 3b.
[0024]
The caulking can be performed, for example, by inserting a caulking jig (punch) into a through hole in the inner periphery of the stem portion of the outer joint member 3b. That is, after the stem portion of the outer joint member 3b is fitted to the inner periphery of the hub wheel 2, a caulking jig having an outer diameter larger than the inner diameter of the through hole of the stem portion is pushed into the through hole, whereby the stem portion is formed. The diameter of the swaged portion 3e is increased from the inner diameter side to the outer diameter side.
[0025]
The outer joint member 3b contains, for example, 0.5 to 0.7% of C, 0.1 to 1.5% of Si, and 0.6 to 1.0% of Mn by weight% as an alloy element, with the balance being the balance. It can be formed of Fe and a steel material as an unavoidable impurity. Among them, those containing 0.6 to 1.2% of Si are preferable. In addition, among the carbon steels for machine structures specified in JIS, medium carbon steels, for example, C is 0.5 to 0.6%, Si is 0.1 to 0.4%, and Mn is 0.6 to 1.0%. %, Or carbon steel containing 0.5 to 0.6% of C, 0.7 to 0.9% of Si, and 0.6 to 1.0% of Mn. The latter steel material can increase the fatigue strength in the unheat-treated portion as compared with the former steel material because of the large content of Si.
[0026]
2A to 2F are enlarged views of a portion A in FIG. 1 and show a foreign matter intrusion prevention means according to the present invention. The foreign matter intrusion prevention means prevents foreign matter from entering the inside of the bearing from the butted portion, and can be configured by, for example, sealing a gap between the butted portions from the outer peripheral side. As the sealing means, for example, an intervening body is interposed near the outer peripheral portion between the end faces of the butted portion (see FIGS. 2A and 2D to 2F), or the outer periphery of the butted portion is formed by both members. (See FIGS. (B) and (c) in the same figure). Specifically, it is as follows.
[0027]
FIG. 2A shows a first embodiment of the present invention, in which the end surface 2c of the hub wheel 2 is on the outer peripheral side of the butted portion of the shoulder 3b4 of the outer joint member 3b, that is, the outer peripheral angle of the end surface 2c of the hub wheel 2. Circumferential grooves 2c1 and 3b5 are formed at the outer peripheral corners of the outer joint member 3b and the shoulder 3b4, respectively, and the O-ring 11 is interposed between the butted portions. As a result, when a large bending moment generated at the time of a sharp turn of the vehicle or a large torque generated at the time of a sudden start is generated, abrasion powder is generated from an abutting surface between the end face 2c of the hub wheel 2 and the shoulder 3b4 of the outer joint member 3b. Also, the O-ring 11 can prevent intrusion of wear powder into the bearing. As the O-ring 11, for example, nitrile butadiene rubber (NBR), silicone rubber, fluorine rubber, or the like can be used.
[0028]
FIG. 2B shows a second embodiment of the present invention, in which a sealing material 12 is applied to an outer peripheral side of a butt portion between an end face 2c of a hub wheel 2 and an end face of a shoulder 3b4 of an outer joint member 3b. is there. As the sealant 12, for example, Three Bond 1105, Loctite 5910, Shin-Etsu Chemical FE123, or the like can be used.
[0029]
FIG. 2C shows a third embodiment of the present invention, in which an adhesive 13 is applied to an outer peripheral side of a butt portion between an end face 2c of a hub wheel 2 and an end face of a shoulder 3b4 of an outer joint member 3b. is there. Various adhesives can be used as the adhesive 13, for example, a synthetic rubber-based adhesive (three bond 1521 or the like) can be used. Further, an anaerobic adhesive can be interposed in the outer peripheral portion between the end face 2c of the hub wheel and the end face of the shoulder of the outer joint member 3b.
[0030]
FIG. 2D shows a fourth embodiment of the present invention, which is on the outer peripheral side of the abutting portion between the end face 2c of the hub wheel 2 and the end face of the shoulder 3b4 of the outer joint member 3b, that is, the outer circumference of the end face 2c of the hub wheel 2. Circumferential grooves 2c1 and 3b5 are formed in the corners and the outer peripheral corners of the shoulder 3b4 of the outer joint member 3b, respectively, and the grease 14 is interposed in the butted portions. The grease 14 is preferably the same as the grease sealed inside the bearing. The same grease does not deteriorate the grease inside the bearing. Therefore, it is sufficient that the grease inside the bearing does not deteriorate.
[0031]
FIG. 2E shows a fifth embodiment of the present invention, which is a modification of the fourth embodiment. A circle is formed on the outer peripheral side of the abutting portion between the end face 2c of the hub wheel 2 and the shoulder 3b4 of the outer joint member 3b, that is, the outer peripheral corner of the end face 2c of the hub wheel 2 and the outer peripheral corner of the shoulder 3b4 of the outer joint member 3b. The circumferential grooves 2c1 and 3b5 are formed, the grease 14 is interposed in the butted portion, and the butted portion is closed by a cylindrical plate member 15 so that the grease 14 is not scattered inside the bearing. The plate member 15 is press-fitted into the outer peripheral surface of the hub wheel 2, and there is a gap between the plate member 15 and the outer peripheral surface of the outer joint member 3b. FIG. 2F shows a sixth embodiment of the present invention, which is a modification of the fifth embodiment. 2 (e), the plate member 15 is pressed into the outer peripheral surface of the hub wheel 2 and also into the outer peripheral surface of the outer joint member 3b. As the plate member 15, for example, SPC, resin PP, PA6, PA66, or the like can be used.
[0032]
Next, FIG. 3 shows another embodiment of the drive wheel bearing, in which an outer member 1 having a double-row raceway surface 1a on the inner periphery and a raceway surface 2a opposed to the raceway surface 1a on the outboard side. , A constant velocity universal joint 3 having a raceway surface 3a opposed to the raceway surface 1a on the inboard side, and a double row rolling element 4 interposed between the raceway surface 1a and the raceway surfaces 2a, 3a And a retainer 5 for holding the rolling elements 4 at equal intervals in the circumferential direction.
The hub wheel 2 is provided with a wheel mounting flange 2b, and a wheel (not shown) is mounted on the wheel mounting flange 2b using a hub bolt 6 for fixing a wheel. On the other hand, an outer periphery 1b of the outer member 1 is provided with a mounting flange 1d for mounting to a fixing portion (knuckle or the like) on the vehicle body (not shown). The mounting flange 1d is provided with a mounting hole 1e, which is fixed to a fixing portion by a bolt (not shown), and a wheel bearing is mounted on the vehicle body.
[0033]
In the drive wheel bearing, the hub wheel 2 is connected to the outer joint member 3 b of the constant velocity universal joint 3. The outer joint member 3b includes a bowl-shaped mouth portion 3bl and a hollow stem portion 3b2. The difference from the embodiment of FIG. 1 is that the stem portion 3b2 is fitted to the outer periphery of the hub wheel 2, and the hollow hub wheel 2 is expanded from the inner diameter side and caulked (hereinafter, referred to as expanded diameter caulking). I have. As a result, the end face 2c of the outer joint member 3b is pressed against the end face of the shoulder 3b4 of the hub wheel 2, the outer joint member 3b is positioned in the axial direction, and a preload is applied to the rolling elements 4. Each of the rolling elements 4 in the double row has a contact angle, and has a structure in which bearing rigidity is increased by the above-described preload and a moment load can be received.
[0034]
In this case, at the time of caulking, it is necessary to form the caulked portion 3e at a position on the inboard side in the axial direction of the raceway surface 3a so as not to affect the raceway surface 3a.
[0035]
Also in the drive wheel bearing shown in FIG. 3, similarly to the first embodiment, the outer periphery of the abutting portion between the end face 2 c of the outer joint member 3 b and the end face of the shoulder 3 b 4 of the hub wheel 2 is shown in FIGS. A foreign substance intrusion prevention means shown in f) is provided.
In addition, 8 shown in FIGS. 1 and 3 is a cap member. Since the stem portion 3b2 (see FIG. 1) and the hub wheel 2 (see FIG. 2) are hollow, the inside and outside of the constant velocity universal joint communicate with each other. A member is required.
[0036]
【The invention's effect】
As described above, according to the present invention, an outer member having a double-row raceway surface on the inner periphery, a hub wheel having a raceway surface facing one raceway surface of the outer member, and a wheel mounting flange, Constant velocity universal joint outer ring having a raceway surface facing the other raceway surface of the outer member on the outer peripheral surface, and a double row interposed between the raceway surface of the outer member and the raceway surface of the hub wheel and the constant velocity universal joint outer ring And a foreign body intrusion prevention means is provided on the outer peripheral side of the butted portion of the hub wheel and the constant velocity universal joint.
As a result, even if abrasion powder is generated from the abutting surface between the hub wheel and the outer joint member, the abrasion powder does not enter the inside of the bearing, thereby extending the life of the drive wheel bearing.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing one embodiment of a driving wheel bearing according to the present invention.
2 (a) is an enlarged view of a portion A in FIG. 1 and is a longitudinal sectional view showing an example of foreign matter intrusion prevention means.
(B) is an enlarged view of a portion A in FIG. 1 and is a longitudinal sectional view showing another example of the foreign matter intrusion prevention means.
(C) is an enlarged view of a portion A in FIG. 1 and is a longitudinal sectional view showing another example of the foreign matter intrusion prevention means.
(D) is an enlarged view of part A of FIG. 1 and is a longitudinal sectional view showing another example of the foreign matter intrusion prevention means.
(E) is an enlarged view of a portion A in FIG. 1 and is a longitudinal sectional view showing another example of the foreign matter intrusion prevention means.
(F) is an enlarged view of a portion A in FIG. 1 and is a longitudinal sectional view showing another example of the foreign matter intrusion prevention means.
FIG. 3 is a longitudinal sectional view showing another embodiment of the drive wheel bearing according to the present invention.
FIG. 4 is a longitudinal sectional view of a conventional driving wheel bearing.
[Explanation of symbols]
Reference Signs List 1 outer member 1a raceway surface 2 hub wheel 3 constant velocity universal joint 3b outer joint member 3b1 mouth part 4 rolling element 5 retainer 6 hub bolts 7A, 7B seal 8 cap member

Claims

An outer member having a double row of raceway surfaces on the inner periphery,
A hub wheel having a raceway surface facing one raceway surface of the outer member and a wheel mounting flange,
An outer joint member of a constant velocity universal joint having an outer peripheral surface having a raceway surface facing the other raceway surface of the outer member,
In a drive wheel bearing constituted by a double row rolling element interposed between the raceway surface of the outer member and each raceway surface of the hub wheel and the outer joint member,
A bearing for a drive wheel, comprising a foreign matter intrusion preventing means for preventing foreign matter from entering the inner space of the bearing from the butted portion on the outer peripheral side of the butted portion between the hub wheel and the constant velocity universal joint.

2. The drive wheel bearing according to claim 1, wherein the outer joint member has a mouth portion and a stem portion, and a hub wheel is fitted around the outer periphery of the stem portion.

The drive wheel bearing according to claim 1, wherein the outer joint member has a mouth portion and a stem portion, and the stem portion is fitted to an outer periphery of the hub wheel on the inboard side.

4. The drive wheel bearing according to claim 1, wherein said foreign matter intrusion prevention means is an O-ring.

4. The drive wheel bearing according to claim 1, wherein said foreign matter intrusion prevention means is formed by applying grease.

The drive wheel bearing according to any one of claims 1 to 3, wherein the foreign matter intrusion prevention means is an adhesive.

The drive wheel bearing according to any one of claims 1 to 6, wherein a member on the inner diameter side of the hub wheel and the outer race of the constant velocity universal joint is plastically deformed in a radially expanding direction.