JP3815376B2

JP3815376B2 - Rolling bearing unit for wheel support

Info

Publication number: JP3815376B2
Application number: JP2002148895A
Authority: JP
Inventors: 善久大貫; 裕也宮崎
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 2002-05-23
Filing date: 2002-05-23
Publication date: 2006-08-30
Anticipated expiration: 2016-09-25
Also published as: JP2003042173A

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】
自動車の車輪は、車輪支持用転がり軸受ユニットにより懸架装置に支持する。この様な場合に使用する車輪支持用転がり軸受ユニットとして、従来から例えば、特開昭６３−１０６４２６号公報、同６３−１８４５０１号公報、同６２−２１４８８９号公報、特開平３−３１００１号公報、米国特許第４５３７２７０号明細書、同４９５８９４４号明細書、同５２２６７３８号明細書、同５４９０７３２号明細書等に記載されたものが知られている。又、図８は、従来から広く実施されている車輪支持用転がり軸受ユニットの１例を示している。この車輪支持用転がり軸受ユニット１は、シャフト部材２と、内輪３と、外輪４と、複数個の転動体５、５とを備える。このうちのシャフト部材２の外周面の外端部（外とは、自動車への組み付け状態で幅方向外寄りとなる側を言い、各図の左側となる。反対に幅方向中央寄りとなる側を内と言い、各図の右側となる。）で上記外輪４から突出した部分には、車輪を支持する為の第二のフランジ６を形成している。又、このシャフト部材２の中間部には第一の内輪軌道７を、同じく内端部には外径寸法が小さくなった段部８を、それぞれ形成している。
【０００３】
そして、この段部８に、その外周面に第二の内輪軌道９を形成した上記内輪３を外嵌している。上記シャフト部材２の内端部には雄ねじ部１０を形成し、この雄ねじ部１０の先端部を、上記内輪３の内端面よりも内方に突出させている。そして、この雄ねじ部１０に螺合したナット１１と上記段部８の段差面１２との間で上記内輪３を挟持する事により、この内輪３を上記シャフト部材２の所定位置に結合固定している。上記雄ねじ部１０の先端部外周面には係止凹部１７を形成している。そして、上記ナット１１を所定のトルクで緊締した後、このナット１１の一部で上記係止凹部１７に整合する部分を直径方向内方にかしめ付ける事により、このナット１１の緩み止めを図っている。尚、上記シャフト部材２に１対の内輪を外嵌し、これら１対の内輪の外周面に、第一、第二の内輪軌道７、９を設ける構造も、従来から知られている。
【０００４】
又、上記外輪４の内周面には、上記第一の内輪軌道７と対向する第一の外輪軌道１３及び上記第二の内輪軌道９に対向する第二の外輪軌道１４を形成している。そして、これら第一、第二の内輪軌道７、９と第一、第二の外輪軌道１３、１４との間に上記転動体５、５を、それぞれ複数個ずつ設けている。これら各転動体５、５の設置空間の外端開口はシールリング２２により、内端開口は蓋体２９により、それぞれ塞いでいる。尚、図示の例では、転動体５、５として玉を使用しているが、重量の嵩む自動車用の車輪支持用転がり軸受ユニットの場合には、これら転動体としてテーパころを使用する場合もある。
【０００５】
上述の様な車輪支持用転がり軸受ユニット１を自動車に組み付けるには、上記外輪４を、その外周面の一部に形成した第一のフランジ１５により懸架装置に固定し、上記第二のフランジ６に車輪を固定する。この結果、この車輪が懸架装置に対して回転自在に支持される。
【０００６】
又、前記米国特許第５２２６７３８号明細書には、図９に示す様な構造の車輪支持用転がり軸受ユニット１が記載されている。この従来構造の第２例の場合には、シャフト部材２の内端部に形成した円筒部の一部で内輪３の内端面よりも内方に突出した部分を直径方向外方に折り曲げる事により、かしめ部１６を形成している。そして、このかしめ部１６と段部８の段差面１２との間で、上記内輪３を挟持している。
【０００７】
【発明が解決しようとする課題】
図８に示した従来構造の第１例の場合には、雄ねじ部１０の先端部に係止凹部１７を形成する作業、及びナット１１の一部を直径方向内方にかしめ付ける作業が必要になる。この為、車輪支持用転がり軸受ユニット１の部品製造作業及び組立作業が面倒になり、コストが嵩む。
【０００８】
又、図９に示した第２例の構造の場合、シャフト部材２に対して内輪３を結合固定する為のかしめ部１６の形成時に、このかしめ部１６が隣接する内輪３の内周面に、直径方向外方に向いた力が加わる。この為、この内輪３の直径が僅かとは言え変化する。そして、この変化量が大きくなると、この内輪３に亀裂等の損傷が発生する可能性が生じるだけでなく、転動体５、５に付与した予圧を適正値に維持する作業が面倒になり、上記内輪３を含む車輪支持用転がり軸受ユニット１の耐久性を確保する事が難しくなる可能性がある。特に、上記シャフト部材２に対して上記内輪３が回転する事を防止すべく、上記かしめ部１６のかしめ強度を十分に確保しようとした場合には、上記変形量が大きくなり易く、上記内輪３の耐久性確保が難しくなる。
【０００９】
この様な事情に鑑みて特願平８−３６８００号には、内輪の端面とかしめ部との間にスペーサリングを設け、かしめ部の形成作業に伴う、直径方向外方に向いた力をこのスペーサリングにより受ける構造が開示されている。この先発明に係る構造によれば、かしめ部の形成作業に伴って発生する、直径方向外方に向いた力の大部分を上記スペーサリングが受ける。従って、上記内輪にはこの直径方向外方に向いた力が殆ど伝わらず、この内輪の損傷防止を図れる。但し、この様なスペーサリングを設けた構造の場合でも、上記かしめ部自体、円筒部からの加工量が多く、かしめ作業に伴う変形に基づいて亀裂等が発生し易く、耐久性の確保が難しい。
【００１０】
本発明の車輪支持用転がり軸受ユニットは、この様な事情に鑑みて、かしめ部に亀裂等の損傷が発生しにくくすると共に、シャフト部材に対し内輪を固定するナットの緩み止めを図る為の係止凹部の形成作業やナットのかしめ付け作業を省略する事により、コスト低減を図る事を目的に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何れも、従来の、或は先発明の車輪支持用転がり軸受ユニットと同様に、外周面に第一のフランジを、内周面に複列の外輪軌道を、それぞれ設けた外輪と、端部外周面に第二のフランジを設けたシャフト部材と、外周面に内輪軌道を有し上記シャフト部材に外嵌した、少なくとも１個の内輪と、この内輪を含んで上記シャフト部材と共に回転する部分の外周面に設けた第一、第二の内輪軌道と上記複列の外輪軌道との間に、それぞれ複数個ずつ設けた転動体とを備える。そして、上記シャフト部材の端部に形成した円筒部の一部で上記内輪よりも突出した部分を直径方向外方にかしめ広げ、このかしめ広げた部分により上記内輪を抑え付ける事により、上記内輪を上記シャフト部材に固定している。
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、このシャフト部材の端部に段差部を、上記円筒部の基端側の外径よりも先端側の外径が小さくなる状態で形成している。そして、この円筒部のうちの外径の小さくなった部分を直径方向外方にかしめ広げている。
尚、好ましくは、上記内輪の開口周縁部で上記円筒部をかしめ広げた部分の外周面が押し付けられる部分を、開口端に向う程径が大きくなる、円錐凹面状の傾斜面とする。
【００１２】
更に好ましくは、次の▲１▼〜▲５▼の構成要件を、それぞれ単独で、或は▲１▼〜▲５▼のうちから選択される複数の構成要件を、上記必須要件に組み合わせて実施する。
▲１▼ 上記円筒部を構成すべく、上記シャフト部材の端部に形成する円形の凹部の先端の、このシャフト部材の軸方向に関する位置は、上記円筒部寄りに存在する第二の内輪軌道に当接する転動体の中心の上記シャフト部材の軸方向に関する位置よりも、上記シャフト部材の端部側に位置する。
▲２▼ 上記第二の内輪軌道に当接する転動体の中心と、上記内輪の端面若しくはこの内輪の肩部の端面との、上記シャフト部材の軸方向に関する距離は、上記転動体の外径の０．７５倍以上である。
▲３▼ 上記内輪の端部で上記傾斜面を形成した部分の外径を、この内輪の肩部の外径よりも小さくする。
▲４▼ 上記シャフト部材の先端部外周面の一部で、上記傾斜面の小径側端部に対向する部分に凹溝を、上記外周面の全周に亙って形成し、上記シャフト部材の端部に形成した円筒部のうちの凹溝よりも先端寄り部分を、直径方向外方にかしめ広げる。
▲５▼ 転動体から内輪に加わる荷重の作用線の延長位置を、上記傾斜面よりもシャフト部材の軸方向中央寄りで、このシャフト部材の外径が変化しない部分に存在させる。
【００１３】
【作用】
上述の様に構成される本発明の車輪支持用転がり軸受ユニットにより、懸架装置に対して車輪を回転自在に支持する作用は、従来の車輪支持用転がり軸受ユニットと同様である。
特に、本発明の車輪支持用転がり軸受ユニットの場合には、シャフト部材の端部に形成した円筒部をかしめ広げる部分を、段差部を介して外径が小さくなった部分としている為、かしめ広げ作業に伴って円筒部に無理な力が加わりにくくなって、かしめ広げ部分に亀裂等の損傷が発生しにくくなる。
【００１４】
【発明の実施の形態】
図１〜２は、前記▲１▼▲２▼の構成要件を組み込んだ、本発明を適用可能な構造の第１例を示している。尚、本例の特徴は、シャフト部材２に対して内輪３を固定する部分の構造にある。その他の部分の構造及び作用に就いては、前述の図８に示した従来構造と同様であるから、重複する説明を省略若しくは簡略にし、以下、本発明の特徴部分を中心に説明する。
【００１５】
シャフト部材２の内端部に形成した段部８の中間部内端寄り部分で、この段部８に外嵌した内輪３の内端部内周面に、内端開口に向かう程内径が大きくなる、円錐凹面状の傾斜面１９を形成している。この傾斜面１９が上記シャフト部材２の中心軸に対し傾斜している傾斜角度θは、２０〜６０度程度とする。又、上記シャフト部材２の内端面には円形の凹部２０を形成する事により、このシャフト部材２の内端部に円筒部２１を形成している。本例の場合にこの円筒部２１は、上記シャフト部材２の内端部で、ほぼ上記内輪３の肩部２３の内側部分に存在する。
【００１６】
上述の様な傾斜面１９を形成した内輪３を、上記シャフト部材２の内端部に設けた円筒部２１をかしめ広げる事によりこのシャフト部材２に固定し、本発明を適用可能な構造である、車輪支持用転がり軸受ユニットとする際には、前記図９に示した従来構造の場合に比べて、かしめ部分の変形量が少なくて済む。即ち、上記従来構造の場合にはかしめ部１６を形成する為、シャフト部材２の内端部に形成した円筒部を直径方向外方に向け、９０度折り曲げるのに対して、本発明の車輪支持用転がり軸受ユニットを構成すべく、上記円筒部２１をかしめ広げる際には、この円筒部２１を上記傾斜角度θ（＝２０〜６０度）だけ変形させれば良い。この為、このかしめ部分に発生する歪みを小さく抑えて、このかしめ部に割れ等の損傷が発生するのを抑える事ができる。又、上記変形量を少なく抑える為、このかしめ部を形成する事に基づき、上記円筒部２１の周囲に存在する部材である上記内輪３に、この内輪３の直径方向外方に加わる力を低減できて、この内輪３の損傷防止を図れる。
【００１７】
尚、上記円筒部２１を直径方向外方にかしめ広げる作業は、鍛造加工、或は揺動プレス加工により行なう。何れの加工法を採用する場合でも、図２に示す様に、上記円筒部２１の内径側にプレス型２５を押し込み、上記円筒部２１を直径方向外方にかしめ広げる。特に、かしめ作業に揺動プレス加工を採用すれば、成形時の荷重を小さくして、軸受内部への影響をなくし、成形後の予圧管理を適正にできると言った利点がある。又、上記円筒部２１の奥端縁（この円筒部２１の内径が変化しない部分の奥端）と上記内輪３の端面２４との距離Ｌは、車輪支持用転がり軸受ユニットの大きさ等の応じて設計的に定めるが、一般的な乗用車用の車輪支持用転がり軸受ユニットの場合で、５〜１５mm程度とするのが好ましい。
【００１８】
又、上記円筒部２１を構成すべく、上記シャフト部材２の端部に形成する円形の凹部２０の先端位置は、複列に配置した転動体５、５のうち、内側の列を構成する転動体５の中心よりも内側に位置させている。即ち、図１に点Ｘで示した、上記凹部２０の先端の、上記シャフト部材２の軸方向に関する位置は、第二の内輪軌道である、上記内輪３の外周面に設けた第二の内輪軌道９に当接する転動体５の中心の、上記シャフト部材２の軸方向に関する位置よりも、上記シャフト部材２の内端部側に位置させている。従って、車輪支持用転がり軸受ユニットを構成するシャフト部材２と外輪４との間にラジアル荷重が加わり、上記転動体５から上記第二の内輪軌道９にラジアル荷重が加わった場合でも、上記シャフト部材２の一部でこのラジアル荷重を受ける部分が充実体である為、このシャフト部材２の耐久性を十分に確保できる。
【００１９】
更に、上記第二の内輪軌道９に当接する転動体５の中心と、上記内輪３の端面２４との、上記シャフト部材２の軸方向に関する距離Ｍを、上記各転動体５、５の外径Ｄの０．７５倍以上（Ｍ≧０．７５Ｄ）としている。この様に、転動体５の中心と端面２４との距離Ｍを確保している為、上記内輪３の肩部２３や第二の内輪軌道９部分の寸法精度や形状精度が悪化する事を防止して、車輪支持用転がり軸受ユニットの機能を確保できる。即ち、これら各部分の寸法精度や形状精度を良好に確保できるので、車輪支持用転がり軸受ユニットの運転時に振動等が発生するのを防止すると共に、転動体５の転動面や第二の内輪軌道９の転がり疲れ寿命等を確保できる。尚、図示の例では、第一の内輪軌道７をシャフト部材２の中間部外周面に直接形成しているが、この第一の内輪軌道７は、シャフト部材２と別体の内輪に形成し、この内輪をこのシャフト部材２に外嵌固定しても良い。
【００２０】
次に、図３は、前記▲１▼▲２▼▲５▼の構成要件を組み込んだ、本発明を適用可能な構造の第２例を示している。本例の場合には、シャフト部材２の内端部で、このシャフト部材２に外嵌した内輪３の端面２４よりも内方に突出した部分に、スペーサリング１８を外嵌している。このスペーサリング１８の内半部内周面には、内端開口に向かう程内径が大きくなる、円錐凹面状の傾斜面１９を形成している。そして、上記シャフト部材２の内端部で上記スペーサリング１８の内側に存在する円筒部２１を直径方向外方にかしめ広げる事により、上記スペーサリング１８を上記内輪３の端面２４に向け抑え付けて、この内輪３を上記シャフト部材２に結合固定している。又、第二の内輪軌道９と第二の外輪軌道１４との間に設けた転動体５から内輪３に加わる荷重の作用線（接触角を表す鎖線αと一致する）の延長位置は、上記傾斜面１９よりも段部８の軸方向中央寄りで、外径が変化しない部分に存在する。
【００２１】
本例の場合、この様なスペーサリング１８を設ける事により、上記円筒部２１をかしめ広げる際のかしめ強度を十分に大きくした場合でも、上記内輪３が直径方向に弾性変形する事を確実に防止できる。即ち、本例の場合には、上記円筒部２１をかしめ広げる際に加わる、直径方向外方に向いた力は、シャフト部材２に外嵌したスペーサリング１８が受ける。従って、上記円筒部２１をかしめ広げる作業に伴って、上記内輪３の直径が変化する事が、前述した第１例の場合よりも少なくなる（殆ど変化しなくなる）。尚、仮にスペーサリング１８の寸法精度、及び形状精度が悪化しても、車輪支持用転がり軸受ユニットの性能には何らの悪影響も及ぼさない。又、本例の場合には、上記荷重の作用線の延長位置を規制している為、この荷重が上記円筒部２１をかしめ広げた部分に作用する事を防止して、かしめ固定部分の耐久性を確保できる。スペーサリング１８を設けた点、並びに作用線の延長位置を規制した点以外の構成及び作用は、前述した第１例の場合と同様である。
【００２２】
次に、図４は、前記▲１▼▲２▼▲３▼▲５▼の構成要件を組み込んだ、本発明を適用可能な構造の第３例を示している。本例の場合には、シャフト部材２の内端部に外嵌した内輪３ａの内端部で傾斜面１９を形成した部分の外径を、この内輪３ａの肩部２３の外径よりも小さくして、内輪円筒部２６としている。この様な本例の場合、上記シャフト部材２の内端部に形成した円筒部２１を、上記傾斜面１９に向けて直径方向外方にかしめ広げ、上記内輪３をシャフト部材２に固定する際には、上記内輪円筒部２６が、かしめ広げに伴う応力の大部分を受ける。従って、肩部２３に比較して薄肉の内輪円筒部２６の変形量は多くなるが、上記内輪３ａの肩部２３及び第二の内輪軌道９の変形量を小さくできる。この結果、車輪支持用転がり軸受ユニットの回転精度を十分良好な状態に維持できる。尚、本例の場合には、上記第二の内輪軌道９に当接する転動体５の中心と、上記内輪３ａの肩部２３の端面２４ａとの、上記シャフト部材２の軸方向に関する距離Ｍを、上記各転動体５、５の外径Ｄの０．７５倍以上（Ｍ≧０．７５Ｄ）としている。又、本例の場合も、荷重の作用線の延長位置を規制して、かしめ固定部分の耐久性確保を図っている。その他の構成及び作用は、前述した第１例の場合と同様である。
【００２３】
次に、図５は、前記▲１▼▲２▼の構成要件を組み込んだ、本発明を適用可能な構造の第４例を示している。上述した第１〜３例の場合には、外輪４を回転しない静止輪とし、シャフト部材２を回転させる構造であったのに対して、本例の場合には、シャフト部材２を懸架装置に支持して回転させず、外輪４を車輪と共に回転する回転輪としている。回転側と静止側とが逆になった以外の構成及び作用は、前述した第１例の場合と同様である。
【００２４】
次に、図６は、前記▲１▼▲２▼の構成要件を組み込んだ、本発明の実施の形態の１例を示している。本例の場合、シャフト部材２の内端部で内輪３の嵌合部よりも突出した部分の外径を、この嵌合部の外径よりも小さくしている。即ち、上記シャフト部材２の内端部に形成した円筒部２１の基端部外周面で、この内輪３の内端開口部に形成した傾斜面１９よりも少しだけ第二の内輪軌道９に寄った部分に、０．０２〜１mm程度の僅かな段差Ｈを有する段差部２７を形成している。そして、上記円筒部２１のうちの外径の小さくなった部分を、直径方向外方にかしめ広げ、上記傾斜面１９を抑え付ける様にしている。この様に円筒部２１を直径方向外方にかしめ広げる際には、上記段差部２７がかしめ広げ作業に伴って折れ曲がる部分の起点となる。この為、かしめ広げ作業に伴って上記円筒部２１に無理な力が加わりにくくなって、かしめ広げ部分に亀裂等の損傷が発生しにくくなる。その他の構成及び作用は、前述した第１例の場合と同様である。尚、本例の構造を上述した、本発明を適用可能な構造の第４例に適用する場合には、軸方向に関する内外方向が逆になる。
【００２５】
次に、図７は、前記▲１▼▲２▼▲４▼の構成要件を組み込んだ、本発明を適用可能な構造の第５例を示している。本例の場合、シャフト部材２の内端部外周面の一部で、内輪３の内端部に形成した傾斜面１９の小径側端部に対向する部分に、０．１〜２mm程度の深さＫを有する凹溝２８を、上記外周面の全周に亙って形成している。そして、上記シャフト部材２の内端部に形成した円筒部２１のうちの上記凹溝２８よりも内端寄り部分を、直径方向外方にかしめ広げ、上記傾斜面１９を抑え付ける様にしている。この様に円筒部２１を直径方向外方にかしめ広げる際には、上記凹溝２８がかしめ広げ作業に伴って折れ曲がる部分の起点となる。この為、かしめ広げ作業に伴って上記円筒部２１に無理な力が加わりにくくなって、かしめ広げ部分に亀裂等の損傷が発生しにくくなる。その他の構成及び作用は、前述した第１例の場合と同様である。尚、本例の構造を上述した、本発明を適用可能な構造の第４例に適用する場合にも、軸方向に関する内外方向が逆になる。
【００２６】
【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、内輪の直径が変化する事を防止して、この内輪及びこの内輪を固定する為のかしめ広げ部分が、上記内輪の固定作業に基づいて損傷する可能性を低くできる。
【図面の簡単な説明】
【図１】本発明を適用可能な構造の第１例を示す半部断面図。
【図２】シャフト部材の内端部に形成した円筒部をかしめ広げる状態を示す、要部拡大断面図。
【図３】本発明を適用可能な構造の第２例を示す半部断面図。
【図４】同第３例を示す半部断面図。
【図５】同第４例を示す半部断面図。
【図６】本発明の実施の形態の１例を示す要部拡大断面図。
【図７】本発明を適用可能な構造の第５例を示す要部拡大断面図。
【図８】従来構造の第１例を示す半部断面図。
【図９】同第２例を示す半部断面図。
【符号の説明】
１車輪支持用転がり軸受ユニット
２シャフト部材
３、３ａ内輪
４外輪
５転動体
６第二のフランジ
７第一の内輪軌道
８段部
９第二の内輪軌道
１０雄ねじ部
１１ナット
１２段差面
１３第一の外輪軌道
１４第二の外輪軌道
１５第一のフランジ
１６かしめ部
１７係止凹部
１８スぺーサリング
１９傾斜面
２０凹部
２１円筒部
２２シールリング
２３肩部
２４、２４ａ端面
２５プレス型
２６内輪円筒部
２７段差部
２８凹溝
２９蓋体[0001]
BACKGROUND OF THE INVENTION
The wheel support rolling bearing unit according to the present invention is used for rotatably supporting the wheel of an automobile with respect to a suspension device.
[0002]
[Prior art]
The wheels of the automobile are supported on the suspension device by a rolling bearing unit for supporting the wheels. Conventionally, as a wheel bearing rolling bearing unit used in such a case, for example, JP-A-63-106426, JP-A-63-184501, JP-A-62-214889, JP-A-3-31001, U.S. Pat. Nos. 4,537,270, 4,958,944, 5,226,738, 5,490,732 and the like are known. FIG. 8 shows an example of a wheel bearing rolling bearing unit that has been widely used in the past. The wheel support rolling bearing unit 1 includes a shaft member 2, an inner ring 3, an outer ring 4, and a plurality of rolling elements 5 and 5. Outer end of the outer peripheral surface of the shaft member 2 (outside means the side that is outward in the width direction when assembled to the automobile, and is the left side of each figure. On the contrary, the side that is closer to the center in the width direction Is the right side of each figure), and a second flange 6 for supporting the wheel is formed in a portion protruding from the outer ring 4 in FIG. Further, a first inner ring raceway 7 is formed at an intermediate portion of the shaft member 2, and a step portion 8 having a smaller outer diameter is formed at the inner end portion.
[0003]
And the said inner ring | wheel 3 which formed the 2nd inner ring raceway 9 in the outer peripheral surface at this step part 8 is externally fitted. A male screw portion 10 is formed at the inner end portion of the shaft member 2, and the tip end portion of the male screw portion 10 protrudes inward from the inner end surface of the inner ring 3. Then, the inner ring 3 is clamped and fixed to a predetermined position of the shaft member 2 by sandwiching the inner ring 3 between the nut 11 screwed into the male threaded portion 10 and the stepped surface 12 of the stepped portion 8. Yes. A locking recess 17 is formed on the outer peripheral surface of the distal end portion of the male screw portion 10. Then, after tightening the nut 11 with a predetermined torque, a portion of the nut 11 that is aligned with the locking recess 17 is caulked inward in the diametrical direction to prevent the nut 11 from loosening. Yes. A structure in which a pair of inner rings are externally fitted to the shaft member 2 and first and second inner ring raceways 7 and 9 are provided on the outer peripheral surfaces of the pair of inner rings has been conventionally known.
[0004]
A first outer ring raceway 13 facing the first inner ring raceway 7 and a second outer ring raceway 14 facing the second inner ring raceway 9 are formed on the inner peripheral surface of the outer ring 4. . A plurality of rolling elements 5 and 5 are provided between the first and second inner ring raceways 7 and 9 and the first and second outer ring raceways 13 and 14, respectively. The outer end openings of the installation spaces of the rolling elements 5 and 5 are closed by the seal ring 22, and the inner end openings are closed by the lid 29. In the illustrated example, balls are used as the rolling elements 5 and 5. However, in the case of a rolling bearing unit for supporting a wheel for an automobile having a heavy weight, tapered rollers may be used as these rolling elements. .
[0005]
In order to assemble the wheel-supporting rolling bearing unit 1 as described above to an automobile, the outer ring 4 is fixed to a suspension device by a first flange 15 formed on a part of the outer peripheral surface thereof, and the second flange 6 is Secure the wheels to the As a result, this wheel is rotatably supported with respect to the suspension device.
[0006]
Further, in the specification of US Pat. No. 5,226,738, a wheel support rolling bearing unit 1 having a structure as shown in FIG. 9 is described. In the case of the second example of this conventional structure, a portion of the cylindrical portion formed at the inner end of the shaft member 2 that protrudes inward from the inner end surface of the inner ring 3 is bent radially outward. The caulking portion 16 is formed. The inner ring 3 is sandwiched between the caulking portion 16 and the step surface 12 of the step portion 8.
[0007]
[Problems to be solved by the invention]
In the case of the first example of the conventional structure shown in FIG. 8, it is necessary to perform an operation of forming the locking recess 17 at the tip of the male screw portion 10 and an operation of caulking a part of the nut 11 inward in the diameter direction. Become. For this reason, the parts manufacturing work and assembling work of the wheel bearing rolling bearing unit 1 become troublesome, and the cost increases.
[0008]
Further, in the case of the structure of the second example shown in FIG. 9, when the caulking portion 16 for fixing the inner ring 3 to the shaft member 2 is formed, the caulking portion 16 is formed on the inner peripheral surface of the adjacent inner ring 3. A force directed outward in the diameter direction is applied. For this reason, the diameter of the inner ring 3 changes although it is slight. And when this amount of change becomes large, not only the possibility of occurrence of damage such as cracks in the inner ring 3 arises, but the work of maintaining the preload applied to the rolling elements 5, 5 at an appropriate value becomes troublesome. It may be difficult to ensure the durability of the wheel bearing rolling bearing unit 1 including the inner ring 3. In particular, in order to prevent the inner ring 3 from rotating with respect to the shaft member 2 in order to sufficiently secure the caulking strength of the caulking portion 16, the amount of deformation tends to increase, and the inner ring 3 It becomes difficult to ensure durability.
[0009]
In view of such circumstances, in Japanese Patent Application No. 8-36800, a spacer ring is provided between the end face of the inner ring and the caulking portion, and the force directed outward in the diameter direction due to the caulking portion forming operation is A structure received by a spacer ring is disclosed. According to the structure according to the present invention, the spacer ring receives most of the force directed outward in the diametrical direction that is generated along with the forming operation of the caulking portion. Therefore, almost no force directed outward in the diameter direction is transmitted to the inner ring, and damage to the inner ring can be prevented. However, even in the case of such a structure provided with a spacer ring, the amount of processing from the caulking portion itself and the cylindrical portion is large, and cracks are likely to occur due to deformation accompanying caulking work, and it is difficult to ensure durability. .
[0010]
In view of such circumstances, the wheel bearing rolling bearing unit according to the present invention is less susceptible to damage such as cracks in the caulking portion, and is also intended to prevent loosening of the nut that fixes the inner ring to the shaft member. The invention has been invented for the purpose of reducing the cost by omitting the work of forming the recessed portion and the operation of caulking the nut.
[0011]
[Means for Solving the Problems]
Each of the wheel support rolling bearing units of the present invention has a first flange on the outer peripheral surface and a double-row outer ring raceway on the inner peripheral surface, as in the conventional or the wheel support rolling bearing unit of the previous invention. Each including an outer ring, a shaft member provided with a second flange on the outer peripheral surface of the end, at least one inner ring having an inner ring raceway on the outer peripheral surface and externally fitted to the shaft member, and the inner ring And a plurality of rolling elements provided between the first and second inner ring raceways provided on the outer peripheral surface of the portion rotating together with the shaft member, and the double row outer ring raceways. Then, a part of the cylindrical portion formed at the end of the shaft member is caulked outward in the diametrical direction, and the inner ring is restrained by the caulked part, thereby suppressing the inner ring. It is fixed to the shaft member .
In particular, in the rolling bearing unit for supporting a wheel of the present invention , the stepped portion is formed at the end of the shaft member in a state where the outer diameter on the distal end side is smaller than the outer diameter on the proximal end side of the cylindrical portion. is doing. And the part where the outer diameter became small among these cylindrical parts is caulked and spread outward in the diameter direction .
Preferably, a portion where the outer peripheral surface of the portion where the cylindrical portion is caulked and widened at the peripheral edge of the opening of the inner ring is pressed is an inclined surface having a conical concave shape whose diameter increases toward the opening end .
[0012]
More preferably, the following constituents (1) to ( 5) are implemented individually, or a plurality of constituents selected from (1) to ( 5) are combined with the above essential requirements. To do.
(1) In order to constitute the cylindrical portion, the position of the tip of the circular recess formed at the end of the shaft member in the axial direction of the shaft member is the second inner ring raceway located near the cylindrical portion. It is located on the end side of the shaft member with respect to the axial direction of the shaft member at the center of the rolling element in contact.
(2) The distance in the axial direction of the shaft member between the center of the rolling element in contact with the second inner ring raceway and the end face of the inner ring or the end face of the shoulder of the inner ring is the outer diameter of the rolling element. It is 0.75 times or more.
(3) The outer diameter of the portion where the inclined surface is formed at the end of the inner ring is made smaller than the outer diameter of the shoulder of the inner ring.
(4) A concave groove is formed on a part of the outer peripheral surface of the tip end portion of the shaft member, facing the small-diameter side end of the inclined surface, over the entire circumference of the outer peripheral surface. A portion closer to the tip than the concave groove in the cylindrical portion formed at the end is caulked and spread outward in the diameter direction.
(5) The extended position of the line of action of the load applied to the inner ring from the rolling element is located closer to the center of the shaft member in the axial direction than the inclined surface, and the outer diameter of the shaft member does not change.
[0013]
[Action]
The operation of rotatably supporting the wheel with respect to the suspension device by the wheel supporting rolling bearing unit of the present invention configured as described above is the same as that of the conventional wheel supporting rolling bearing unit.
In particular, in the case of the rolling bearing unit for supporting a wheel according to the present invention, the portion where the cylindrical portion formed on the end portion of the shaft member is caulked is a portion where the outer diameter is reduced via the stepped portion, so that the caulking is expanded. It becomes difficult to apply an excessive force to the cylindrical portion with the work, and damage such as a crack is hardly generated in the caulking and spreading portion.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 show a first example of a structure to which the present invention can be applied , which incorporates the constitutional requirements (1) and (2). The feature of this example is the structure of the portion for fixing the inner ring 3 to the shaft member 2. Since the structure and operation of other parts are the same as those of the conventional structure shown in FIG. 8 described above, the overlapping description will be omitted or simplified, and the following description will focus on the characteristic parts of the present invention.
[0015]
The inner diameter increases toward the inner end opening on the inner peripheral surface of the inner ring 3 of the inner ring 3 that is externally fitted to the step portion 8 at a portion near the inner end of the step portion 8 formed at the inner end portion of the shaft member 2. A conical concave surface 19 is formed. The inclination angle θ at which the inclined surface 19 is inclined with respect to the central axis of the shaft member 2 is about 20 to 60 degrees. Further, a cylindrical recess 21 is formed at the inner end of the shaft member 2 by forming a circular recess 20 on the inner end surface of the shaft member 2. In the case of this example, the cylindrical portion 21 is present at the inner end portion of the shaft member 2 and substantially at the inner portion of the shoulder portion 23 of the inner ring 3.
[0016]
The inner ring 3 having the inclined surface 19 as described above is fixed to the shaft member 2 by caulking and expanding the cylindrical portion 21 provided at the inner end portion of the shaft member 2, and the present invention can be applied. When the wheel bearing rolling bearing unit is used, the amount of deformation of the caulking portion can be reduced as compared with the conventional structure shown in FIG. That is, in the case of the above-described conventional structure, in order to form the caulking portion 16, the cylindrical portion formed at the inner end portion of the shaft member 2 is bent 90 degrees outward in the diameter direction, whereas the wheel support of the present invention is When the cylindrical portion 21 is caulked and spread to form a rolling bearing unit, the cylindrical portion 21 may be deformed by the inclination angle θ (= 20 to 60 degrees). For this reason, distortion generated in the caulking portion can be suppressed to be small, and damage such as cracking can be suppressed in the caulking portion. Further, in order to suppress the deformation amount, the force applied to the inner ring 3 that is a member around the cylindrical portion 21 in the outer diameter direction of the inner ring 3 is reduced based on the formation of the caulking portion. Thus, damage to the inner ring 3 can be prevented.
[0017]
The operation of caulking the cylindrical portion 21 outward in the diametrical direction is performed by forging or swing pressing. Regardless of which processing method is employed, as shown in FIG. 2, a press die 25 is pushed into the inner diameter side of the cylindrical portion 21, and the cylindrical portion 21 is caulked outward in the diameter direction. In particular, the use of oscillating press working in the caulking work has the advantage that the load during molding can be reduced, the influence on the inside of the bearing can be eliminated, and the preload management after molding can be properly performed. Further, the distance L between the rear end edge of the cylindrical portion 21 (the rear end of the portion where the inner diameter of the cylindrical portion 21 does not change) and the end surface 24 of the inner ring 3 depends on the size of the wheel bearing rolling bearing unit. However, it is preferably about 5 to 15 mm in the case of a general rolling bearing unit for supporting a wheel for passenger cars.
[0018]
Further, in order to form the cylindrical portion 21, the tip position of the circular recess 20 formed at the end of the shaft member 2 is the rolling element constituting the inner row of the rolling elements 5 and 5 arranged in double rows. It is located inside the center of the moving body 5. That is, the position of the tip of the recess 20 in the axial direction of the shaft member 2 indicated by the point X in FIG. 1 is the second inner ring provided on the outer peripheral surface of the inner ring 3 which is the second inner ring raceway. The center of the rolling element 5 in contact with the track 9 is positioned closer to the inner end of the shaft member 2 than the position in the axial direction of the shaft member 2. Therefore, even when a radial load is applied between the shaft member 2 constituting the wheel supporting rolling bearing unit and the outer ring 4 and a radial load is applied from the rolling element 5 to the second inner ring raceway 9, the shaft member Since the part which receives this radial load in a part of 2 is a solid body, the durability of the shaft member 2 can be sufficiently secured.
[0019]
Further, the distance M in the axial direction of the shaft member 2 between the center of the rolling element 5 contacting the second inner ring raceway 9 and the end surface 24 of the inner ring 3 is defined as the outer diameter of each rolling element 5, 5. 0.75 times or more of D (M ≧ 0.75D). As described above, since the distance M between the center of the rolling element 5 and the end face 24 is secured, it is possible to prevent deterioration of the dimensional accuracy and shape accuracy of the shoulder portion 23 of the inner ring 3 and the second inner ring raceway 9 portion. Thus, the function of the wheel bearing rolling bearing unit can be secured. That is, since the dimensional accuracy and shape accuracy of each of these portions can be ensured satisfactorily, vibration and the like are prevented during operation of the wheel support rolling bearing unit, and the rolling surface of the rolling element 5 and the second inner ring are prevented. The rolling fatigue life of the track 9 can be secured. In the illustrated example, the first inner ring raceway 7 is formed directly on the outer peripheral surface of the intermediate portion of the shaft member 2, but the first inner ring raceway 7 is formed on the inner ring separate from the shaft member 2. The inner ring may be externally fitted and fixed to the shaft member 2.
[0020]
Next, FIG. 3 shows a second example of a structure to which the present invention can be applied , which incorporates the constitutional requirements (1), (2), and ( 5 ). In the case of this example, the spacer ring 18 is externally fitted to the inner end portion of the shaft member 2 that protrudes inward from the end face 24 of the inner ring 3 that is externally fitted to the shaft member 2. On the inner peripheral surface of the inner half of the spacer ring 18, an inclined surface 19 having a conical concave shape is formed, the inner diameter of which increases toward the inner end opening. Then, the cylindrical portion 21 existing inside the spacer ring 18 is caulked and spread outward in the diametrical direction at the inner end portion of the shaft member 2, thereby pressing the spacer ring 18 toward the end surface 24 of the inner ring 3. The inner ring 3 is coupled and fixed to the shaft member 2. Further, the extension position of the line of action of the load applied to the inner ring 3 from the rolling elements 5 provided between the second inner ring raceway 9 and the second outer ring raceway 14 (corresponding to the chain line α representing the contact angle) is as described above. It exists in the part where an outer diameter does not change near the axial center of the step part 8 rather than the inclined surface 19.
[0021]
In the case of this example, by providing such a spacer ring 18, even when the caulking strength when caulking and expanding the cylindrical portion 21 is sufficiently increased, the inner ring 3 is reliably prevented from elastically deforming in the diameter direction. it can. That is, in the case of this example, the force directed outward in the diameter direction applied when the cylindrical portion 21 is caulked and spread is received by the spacer ring 18 that is externally fitted to the shaft member 2. Therefore, the diameter of the inner ring 3 changes with the work of caulking the cylindrical portion 21 less than in the case of the first example described above (almost no change). Even if the dimensional accuracy and shape accuracy of the spacer ring 18 are deteriorated, the performance of the wheel bearing rolling bearing unit is not adversely affected. In the case of this example, since the extension position of the line of action of the load is restricted, this load is prevented from acting on the part where the cylindrical part 21 is caulked and the caulking fixed part is durable. Can be secured. The configuration and operation other than the point of providing the spacer ring 18 and the point of restricting the extended position of the action line are the same as in the case of the first example described above.
[0022]
Next, FIG. 4 shows a third example of a structure to which the present invention can be applied , which incorporates the structural requirements of (1), (2), (3), and ( 5 ). In the case of this example, the outer diameter of the portion where the inclined surface 19 is formed at the inner end portion of the inner ring 3a fitted on the inner end portion of the shaft member 2 is smaller than the outer diameter of the shoulder portion 23 of the inner ring 3a. Thus, the inner ring cylindrical portion 26 is provided. In the case of this example, when the cylindrical portion 21 formed at the inner end portion of the shaft member 2 is caulked outwardly in the diametrical direction toward the inclined surface 19, the inner ring 3 is fixed to the shaft member 2. The inner ring cylindrical portion 26 receives most of the stress accompanying caulking and spreading. Accordingly, although the deformation amount of the thin inner ring cylindrical portion 26 is larger than that of the shoulder portion 23, the deformation amount of the shoulder portion 23 of the inner ring 3a and the second inner ring raceway 9 can be reduced. As a result, the rotational accuracy of the wheel supporting rolling bearing unit can be maintained in a sufficiently good state. In the case of this example, the distance M in the axial direction of the shaft member 2 between the center of the rolling element 5 contacting the second inner ring raceway 9 and the end surface 24a of the shoulder portion 23 of the inner ring 3a is defined. , 0.75 times the outer diameter D of each of the rolling elements 5 and 5 (M ≧ 0.75D). Also in this example, the extension position of the load acting line is regulated to ensure the durability of the caulking fixed portion. Other configurations and operations are the same as those of the first example described above.
[0023]
Next, FIG. 5 shows a fourth example of a structure to which the present invention can be applied , which incorporates the constitutional requirements (1) and (2). In the case of the first to third examples described above, the outer ring 4 is a stationary wheel that does not rotate and the shaft member 2 is rotated. In the present example, the shaft member 2 is used as a suspension device. The outer ring 4 is a rotating wheel that rotates together with the wheels without being supported and rotated. The configuration and operation other than the rotation side and the stationary side being reversed are the same as in the case of the first example described above.
[0024]
Next, FIG. 6 shows an example of an embodiment of the present invention in which the constituent requirements of (1) and ( 2) are incorporated. In the case of this example, the outer diameter of the portion protruding from the fitting portion of the inner ring 3 at the inner end portion of the shaft member 2 is made smaller than the outer diameter of the fitting portion. That is, the outer peripheral surface of the base end portion of the cylindrical portion 21 formed at the inner end portion of the shaft member 2 is slightly closer to the second inner ring raceway 9 than the inclined surface 19 formed at the inner end opening portion of the inner ring 3. A stepped portion 27 having a slight step H of about 0.02 to 1 mm is formed in the portion. And the part where the outer diameter became small among the said cylindrical parts 21 is caulked and spread outward in the diameter direction, and the said inclined surface 19 is suppressed. In this way, when the cylindrical portion 21 is caulked and spread outward in the diameter direction, the stepped portion 27 becomes a starting point of a portion that is bent along with caulking and spreading work. For this reason, it becomes difficult to apply an excessive force to the cylindrical portion 21 with the caulking and spreading work, and damage such as cracks is less likely to occur in the caulking and spreading portion. Other configurations and operations are the same as those of the first example described above. When the structure of this example is applied to the fourth example of the structure to which the present invention can be applied, the inner and outer directions with respect to the axial direction are reversed.
[0025]
Next, FIG. 7 shows a fifth example of a structure to which the present invention can be applied , which incorporates the constitutional requirements (1), (2), and ( 4 ). In the case of this example, a part of the outer peripheral surface of the inner end portion of the shaft member 2 has a depth of about 0.1 to 2 mm at a portion facing the small diameter side end portion of the inclined surface 19 formed at the inner end portion of the inner ring 3. A concave groove 28 having a length K is formed over the entire circumference of the outer peripheral surface. A portion closer to the inner end than the concave groove 28 in the cylindrical portion 21 formed at the inner end portion of the shaft member 2 is caulked outward in the diametrical direction to suppress the inclined surface 19. . Thus, when the cylindrical portion 21 is caulked outward in the diametrical direction, the concave groove 28 becomes a starting point of a portion that is bent along with caulking and spreading work. For this reason, it becomes difficult to apply an excessive force to the cylindrical portion 21 with the caulking and spreading work, and damage such as cracks is less likely to occur in the caulking and spreading portion. Other configurations and operations are the same as those of the first example described above. Even when the structure of this example is applied to the fourth example of the structure to which the present invention can be applied, the inner and outer directions with respect to the axial direction are reversed.
[0026]
【The invention's effect】
Since the wheel bearing rolling bearing unit of the present invention is configured and operates as described above, the diameter of the inner ring is prevented from changing, and the inner ring and the caulking and expanding portion for fixing the inner ring are The possibility of damage based on the fixing work of the inner ring can be reduced .
[Brief description of the drawings]
FIG. 1 is a half sectional view showing a first example of a structure to which the present invention can be applied .
FIG. 2 is an enlarged cross-sectional view of a main part showing a state in which a cylindrical portion formed on an inner end portion of a shaft member is caulked and expanded.
FIG. 3 is a half sectional view showing a second example of a structure to which the present invention can be applied .
FIG. 4 is a half sectional view showing the third example.
FIG. 5 is a half sectional view showing the fourth example.
FIG. 6 is an enlarged cross-sectional view of a main part showing an example of an embodiment of the present invention .
FIG. 7 is an enlarged cross-sectional view of a main part showing a fifth example of a structure to which the present invention can be applied .
FIG. 8 is a half sectional view showing a first example of a conventional structure.
FIG. 9 is a half sectional view showing the second example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wheel support rolling bearing unit 2 Shaft member 3, 3a Inner ring 4 Outer ring 5 Rolling body 6 Second flange 7 First inner ring track 8 Step part 9 Second inner ring track 10 Male thread part 11 Nut 12 Step surface 13 First Outer ring raceway 14 second outer ring raceway 15 first flange 16 caulking portion 17 locking recess 18 spacer ring 19 inclined surface 20 recess 21 cylindrical portion 22 seal ring 23 shoulder portions 24, 24a end face 25 press die 26 inner ring cylindrical portion 27 Stepped portion 28 Concave groove 29 Lid

Claims

A first flange on the outer peripheral surface, a double row outer ring raceway on the inner peripheral surface, an outer ring provided with each, a shaft member provided with a second flange on the outer peripheral surface of the end, and an inner ring raceway on the outer peripheral surface At least one inner ring externally fitted to the shaft member, and first and second inner ring raceways provided on an outer peripheral surface of a portion including the inner ring and rotating together with the shaft member, and the double row outer ring raceway A plurality of rolling elements provided between each of them, and a portion of the cylindrical portion formed at the end of the shaft member that is protruded from the inner ring is caulked outward in the diameter direction, and the caulking is widened. In the wheel bearing rolling bearing unit for fixing the inner ring to the shaft member by restraining the inner ring at a portion, a step portion is provided at the end of the shaft member, and an outer diameter on the base end side of the cylindrical portion. The outer diameter on the tip side is smaller than Was formed in a state, the wheel support rolling bearing unit, characterized in that spread caulking reduced since part of the outside diameter of the cylindrical portion in the diameter direction outwardly.

The wheel support rolling bearing unit according to claim 1, wherein the stepped portion exists in a portion near the second inner ring raceway that is closer to the cylindrical portion than the inclined surface formed in the inner end opening of the inner ring.

The wheel support rolling bearing unit according to any one of claims 1 to 2, wherein the step portion has a step of 0.02 to 1 mm.