JP4289810B2

JP4289810B2 - Drive wheel bearing device

Info

Publication number: JP4289810B2
Application number: JP2001380537A
Authority: JP
Inventors: 英児田島; 博幸小倉
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2001-12-13
Filing date: 2001-12-13
Publication date: 2009-07-01
Anticipated expiration: 2021-12-13
Also published as: JP2003175702A

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車等の駆動側車輪を支持する駆動車輪用軸受装置に関するもので、特に、ハブ輪と等速自在継手と軸受部とをユニット化すると共に、車輪取付フランジの面振れ精度を高めてブレーキジャダーの発生を抑制し得る駆動車輪用軸受装置に関する。
【０００２】
【従来の技術】
一般に制動力が優れたディスクブレーキが普及してきた反面、このディスクブレーキのロータをブレーキパッドにて挟持して制動を行う場合、特に車両低速走行時に振動が発生し、低周波の不快な騒音を誘発することがある。こうした現象はブレーキジャダーと呼ばれ、車両の高性能化、静寂化に伴って、近年、この分析および改善が新しい技術課題として着目されている。
【０００３】
ブレーキジャダーの明確なメカニズムはまだ詳細には解明されてはいないが、その一要因としてブレーキロータのパッド摺接面の振れ精度が挙げられている。この振れ精度は、ブレーキロータ単体の振れ精度だけでなく、ブレーキロータを取り付ける車輪取付フランジの面振れ精度、転がり軸受のアキシアル振れ等、転走面の精度、および転がり軸受の組立精度等々が累積して最終的にブレーキロータ側面の面振れ精度となって現れてくる。
【０００４】
また、近年、低コスト化は言うに及ばず、燃費向上のために軽量化・コンパクト化を狙って等速自在継手とハブ輪と軸受部とをユニット化する傾向にある。これにより、駆動車輪用軸受装置は可及的に余肉が排除されスリム化している。一方、車両の操縦安定性のためには、装置の剛性アップが必要不可欠である。こうした相矛盾する要求を満足しつつ、前述したブレーキロータ側面の面振れ精度対策が講じられている。
【０００５】
図１３は従来の駆動車輪用軸受装置を示し、（ｂ）は縦断面図で、（ａ）はその側面図である。なお、以下の説明では、車両に組み付けた状態で、車両の外側寄りとなる側をアウトボード側（図面左側）、中央寄り側をインボード側（図面右側）という。
【０００６】
この駆動車輪用軸受装置は、内方部材５０と外方部材６０と複列の転動体７０、７０とを備えている。内方部材５０は、ハブ輪５１と別体の内輪５２とからなり、ハブ輪５１のインボード側端部に形成した小径段部５３に内輪５２を圧入している。また、ハブ輪５１の外周にアウトボード側の転走面５１ａ、内輪５２の外周にインボード側の転走面５２ａをそれぞれ形成している。さらにハブ輪５１は車輪（図示せず）を取り付けるための車輪取付フランジ５４をアウトボード側端部に一体に有し、この車輪取付フランジ５４の円周等配位置には車輪を固定するためのハブボルト５５を植設している。
【０００７】
一方、外方部材６０は、外周に車体（図示せず）を取り付けるための車体取付フランジ６１を一体に有し、内周に複列の転走面６０ａ、６０ｂを一体に形成している。これら転走面６０ａ、６０ｂと前述した転走面５１ａ、５２ａ間には保持器７１、７１で円周等配した複列の転動体（ボール）７０、７０をそれぞれ転動自在に収容している。
【０００８】
外方部材６０の両端にシール６２、６３を装着し、外方部材６０と内方部材５０との環状空間を密封し、軸受内部に封入した潤滑グリースの漏洩を防止すると共に、外部からの雨水やダスト等の侵入を防止している。ここでは内方部材５０は、ハブ輪５１と内輪５２を指す。
【０００９】
車輪取付フランジ５４の側面５４ａに環状溝５６を形成し、この環状溝５６内にボルト穴５７を円周方向等配に穿設している。このボルト穴５７にハブボルト５５の外径に形成したナール５５ａ部を圧入固定し、ナット（図示せず）を螺合してブレーキロータ（図示せず）を介して車輪を締結している。
【００１０】
環状溝５６内にボルト穴５７を穿設しているため、ハブボルト５５の圧入によってボルト穴５７周縁の変形や車輪取付フランジ５４の側面５４ａに発生するうねりをこの環状溝５６内にとどめることができ、環状溝５６外の側面５４ａへの影響を抑制している（特開平７−１６４８０９号公報参照）。
【００１１】
また、図１４に示す駆動車輪用軸受装置では、ハブ輪８０と、軸受部９０と、等速自在継手１００とをユニット化して構成している。ハブ輪８０は車輪（図示せず）を取り付けるための車輪取付フランジ８１を一体に有し、この車輪取付フランジ８１の円周等配位置には車輪を固定するためのハブボルト８２を植設している。
【００１２】
軸受部９０は外方部材９１と内方部材９２と複列の転動体９３、９３を備え、外方部材９１には外周に車体（図示せず）に取り付けるための車体取付フランジ９４を一体に有し、内周には複列の転走面９１ａ、９１ａを形成している。一方、内方部材９２には、前記した外方部材９１の転走面９１ａ、９１ａに対向する複列の転走面８０ａ、１０１ａを形成している。これら複列の転走面８０ａ、１０１ａのうち、アウトボード側の転走面８０ａはハブ輪８０の外周に、インボード側の転走面１０１ａは等速自在継手１００の外側継手部材１０１の外周にそれぞれ一体に形成している。複列の転動体９３、９３はこれら転走面９１ａ、８０ａと９１ａ、１０１ａ間に収容し、保持器９５、９５で転動自在に保持している。この場合、内方部材９２はハブ輪８０と外側継手部材１０１を指す。軸受部９０の端部にはシール９６、９７を装着し、軸受内部に封入した潤滑グリースの漏洩と、外部からの雨水やダスト等の侵入を防止している。
【００１３】
等速自在継手１００は外側継手部材１０１と図示しない継手内輪、ケージ、およびトルク伝達ボールとを備え、外側継手部材１０１はカップ状のマウス部１０２と、このマウス部１０２から軸方向に延びる軸部１０３を有し、マウス部１０２の内周には軸方向に延びる曲線状のトラック溝１０２ａを形成している。
【００１４】
ここで、中空に形成した外側継手部材１０１の軸部１０３をハブ輪８０に内嵌すると共に、ハブ輪８０の内周面に凹凸８３を形成し、軸部１０３を拡径してこの凹凸部８３に食い込ませ、その嵌合部を加締めてハブ輪８０と外側継手部材１０１とを塑性結合させている（特開２００１−１８６０５号公報参照）。
【００１５】
こうした駆動車輪用軸受装置では、従来のセレーション等のトルク伝達手段に比べ嵌合部の緩みと摩耗を抑制することができ、この結合部はトルク伝達手段と、ハブ輪と外側継手部材の結合手段とを併せ持つため、一層の軽量・コンパクト化が達成できる。
【００１６】
【発明が解決しようとする課題】
しかしながら、前述した駆動車輪用軸受装置のうち前者において、車輪取付フランジ５４の側面５４ａに環状溝５６を形成し、その後にハブボルト５５を圧入しているため、圧入による変形等を皆無にすることは困難で、側面５４ａの面振れ精度向上には限界があった。また、特に、プレス加工によって形成した鋼製ホイールの場合は、削り加工によって形成したアルミ合金製ホイールに比べ取付面の精度が悪く、環状溝５６の深さや幅寸法によっては、ナット締結によって車輪取付フランジ５４が傾き、かえってブレーキロータ側面（パッド摺接面）の面振れ精度を悪化させることがあった。
【００１７】
したがって、単に車輪取付フランジ５４の側面５４ａに環状溝５６を形成し、ボルト穴５７をその環状溝５６内に穿設するだけでは、ハブボルト５５の圧入による側面５４ａへの影響を完全に防止することは難しく、ブレーキロータ側面の面振れ精度向上に対してまだ幾つかの改善の余地があった。
【００１８】
また、後者の駆動車輪用軸受装置では、軸部１０３を拡径加締することによって、ブレーキロータ（図示せず）を案内するパイロット部８４が拡径してブレーキロータの装着が難しくなるだけでなく、軸部１０３がアウトボード側に延び、車輪取付フランジ８１がインボード側に傾倒することが判った。これらの変形量は加締条件等によってばらつき、予め変形量を予測して設定することは難しく、結果、車輪取付フランジ８１側面の面振れを劣化させることが判った。
【００１９】
本発明は、このような事情に鑑みてなされたもので、装置のユニット化を図り軽量・コンパクト化を達成すると共に、ブレーキロータ側面の面振れ精度向上を図った駆動車輪用軸受装置を提供することを目的としている。
【００２０】
【課題を解決するための手段】
係る目的を達成すべく、本発明のうち請求項１記載の発明は、ブレーキロータを介して車輪を締結する車輪取付フランジを形成し、この車輪取付フランジの周方向に沿って複数のハブボルトを植設するハブ輪と、等速自在継手と、車体に対して車輪を回転自在に支承する複列の転がり軸受とをユニット化し、ハブ輪と等速自在継手の外側継手部材とを嵌合させ、等速自在継手の回転を前記ハブ輪に伝達するようにした駆動車輪用軸受装置において、前記車輪取付フランジに前記ハブボルトを包含する所定の幅を有する環状溝を形成し、前記車輪取付フランジの外径側の接触面を、前記車輪取付フランジの内径側の接触面に対して、車輪側に僅かに突出させて設け、前記ハブ輪の車輪取付フランジが設けられた部位の内径に複数列の溝を直交させた形状をし、硬化させた凹凸部を形成すると共に、この凹凸部に前記外側継手部材の軸部を拡径させて食い込ませることにより、前記ハブ輪と前記外側継手部材とを一体に塑性結合し、前記車輪取付フランジの側面を、前記ハブボルトを圧入および、前記ハブ輪と前記外側継手部材とを一体に塑性結合後に切削加工する切削面とした構成を採用した。
【００２１】
このように、ハブ輪と前記外側継手部材とを一体に塑性結合し、さらには、ハブボルト圧入および前記塑性結合後、すなわち、アッシー後に車輪取付フランジの側面を旋削等によって仕上げ加工するようにしたので、従来のセレーション等のトルク伝達手段に比べ嵌合部の緩みと摩耗を抑制することができ、軽量・コンパクト化が達成できると同時に、塑性結合によって生じる車輪取付フランジの変形やハブボルト圧入によるフランジ側面の面振れ精度への影響を実質的にゼロに抑制することができる。また、車輪取付フランジの外径側を、車輪側に僅かに突出させることにより、ブレーキロータと車輪取付フランジを外径側で密着させ、ブレーキロータの変形の自由度を拘束して、ブレーキロータの面振れを抑制することができる。

【００２２】
また、請求項２に記載の発明は、ハブ輪に形成するブレーキロータのパイロット部を、塑性結合後に切削加工する切削面としたので、塑性結合によってパイロット部が拡径しても容易にブレーキロータを装着することができる。
【００２３】
さらに、請求項３に記載の発明のように、車輪取付フランジにハブボルトを包含する所定の幅を有する環状溝を形成すると共に、この環状溝以外の車輪取付フランジの側面を、ハブボルト圧入後に切削加工した切削面（仕上げ切削面）とすれば、簡便な旋削加工でも仕上げ加工ができ、作業工数削減による低コスト化を図ることができる。
【００２４】
また、請求項４に記載の発明のように、車輪のホイールを鋼製とした時、このホイールとブレーキロータとの接触部のうち、ハブボルトのピッチ円直径に対して外径側の接触部よりも小径に、かつハブボルトのピッチ円直径に対して内径側の接触部よりも大径になるように、環状溝の幅寸法を設定したので、比較的取付部の精度が悪いとされているプレス成形してなる鋼鈑製のホイールであっても、ブレーキロータ側面の面振れ精度を所望の規定値に抑制することができる。
【００２５】
好ましくは、請求項５に記載の発明のように、ハブボルトを環状溝内に植設すると共に、ハブボルトの外径から環状溝の縁部までの距離を１ｍｍ以上とすることによって、ハブボルト周縁部の変形を許容すると共に、フランジ側面の仕上げ加工の作業性を向上することができる。
【００２６】
さらに好ましくは、請求項６に記載の発明のように、環状溝の深さを、少なくとも０．３ｍｍとすれば、環状溝の加工バラツキ、およびハブボルト圧入後の切削バラツキを充分に許容することができる。
【００２８】
また、請求項７に記載の発明のように、車輪取付フランジの側面のうち、ブレーキロータが接触する側の面振れを２０μｍ以下に規制すれば、ブレーキロータ側面の面振れ精度を所望の規定値に抑制することができる。
【００２９】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて詳細に説明する。図１は、本発明に係る駆動車輪用軸受装置の実施形態を示す縦断面図である。この駆動車輪用軸受装置は、ハブ輪１と、複列の転がり軸受２と、等速自在継手３とをユニット化して構成している。なお、以下の説明では、車両に組み付けた状態で、車両の外側寄りとなる側をアウトボード側（図面左側）、中央寄り側をインボード側（図面右側）という。
【００３０】
ハブ輪１は、アウトボード側の端部に車輪（図示せず）を取り付けるための車輪取付フランジ４を一体に有し、この車輪取付フランジ４の円周等配位置には車輪を固定するためのハブボルト１８を植設している。ハブ輪１の内周面には凹凸部５を形成し、熱処理によって表面硬さを５４〜６４ＨＲＣの範囲に硬化層１０を形成する（図中散点模様にて示す）。熱処理としては、局部加熱ができ、硬化層深さの設定が比較的容易にできる高周波誘導加熱による焼入れが好適である。なお、凹凸部５は、図２に示すような複数列の溝を直交させた形状を例示することができる。（ａ）は互いに傾斜した螺旋溝６で、（ｂ）は軸方向、および独立した環状溝６’でアヤメローレット状を形成することができる。また、凹凸部５の凸部は良好な食い込み性を確保するために、三角形状等の尖端形状に形成する。
【００３１】
複列の転がり軸受２は、外方部材７と内方部材８と複列の転動体９、９とからなり、外方部材７は外周に車体（図示せず）に取り付けるための車体取付フランジ７ａを一体に有し、内周には複列の外側転走面７ｂ、７ｂを形成している。一方、内方部材８は、ハブ輪１と後述する外側継手部材１４を指し、外方部材７の外側転走面７ｂ、７ｂに対向するアウトボード側の内側転走面１ａをハブ輪１の外周に、またインボード側の内側転走面１４ａを外側継手部材１４の外周にそれぞれ形成している。複列の転動体９、９をこれら転走面７ｂ、１ａと７ｂ、１４ａ間にそれぞれ収容し、保持器１１、１１で転動自在に保持している。複列の転がり軸受２の端部にはシール１２、１３を装着し、軸受内部に封入した潤滑グリースの漏洩と、外部からの雨水やダスト等の侵入を防止している。
【００３２】
ハブ輪１の外周において、シール１２のシールリップが摺接するシールランド部、内側転走面１ａ、および外側継手部材１４の肩部１６と当接するインロウ部１ｂの表面に高周波焼入れによって硬化層１０’を形成している（図中散点模様にて示す）。ここで複列の転がり軸受２は転動体９、９をボールとした複列アンギュラ玉軸受を例示したが、これに限らず転動体に円すいころを使用した複列円すいころ軸受であっても良い。
【００３３】
等速自在継手３は外側継手部材１４と図示しない継手内輪、ケージ、およびトルク伝達ボールとからなる。外側継手部材１４はカップ状のマウス部１５と、このマウス部１５の底部をなす肩部１６と、この肩部１６から軸方向に延びる軸部１７を有し、マウス部１５の内周には軸方向に延びる曲線状のトラック溝１５ａを形成している。
【００３４】
中空に形成した外側継手部材１４の肩部１６外周には前記した内側転走面１４ａを形成している。また、この軸部１７はハブ輪１のインロウ部１ｂを圧入する小径段部１７ａと、ハブ輪１と嵌合する嵌合部１７ｂを有している。小径段部１７ａに圧入したハブ輪１のインロウ部１ｂを肩部１６によって突合せ状態で、嵌合部１７ｂをハブ輪１に内嵌すると共に、この嵌合部１７ｂの内径にマンドレルを挿入・抜脱させる等、嵌合部１７ｂを適宜な手段で拡径してハブ輪１の凹凸部５に食い込ませ、この嵌合部１７ｂを加締めてハブ輪１と外側継手部材１４とを塑性結合させる。これにより、この結合部はトルク伝達手段と、ハブ輪１と外側継手部材１４の結合手段とを併せ持つため、従来のセレーション等のトルク伝達手段をハブ輪１や外側継手部材１４に形成する必要はなく、また、締結ナット等の固定手段が不要となり、一層装置の軽量・コンパクト化を実現することができる。
【００３５】
外側継手部材１４において、マウス部１５の内周に形成したトラック溝１５ａとシール１３が摺接するシールランド部から転走面１４ａ、および小径段部１７ａに亙って表面硬化処理を施す。硬化処理として高周波誘導加熱による焼入れが好適である。また、拡径する嵌合部１７ｂは、鍛造後の素材表面硬さ２４ＨＲＣ以下の未焼入れ部とし、前記したハブ輪１の凹凸部５の表面硬さ５４〜６４ＨＲＣとの硬度差を３０ＨＲＣ以上に設定するのが好ましい。これにより、嵌合部１７ｂが凹凸部５に容易に、かつ深く食い込み、凹凸部５の先端が潰れることなく強固に両者を塑性結合することができる。
【００３６】
図示はしていないが、中空の外側継手部材１４の内径にエンドキャップを装着して、マウス部１５に封入された潤滑グリースの外部への漏洩と外部からのダスト侵入を防止している。
【００３７】
本実施形態では、車輪取付フランジ４の側面４ａを旋盤等により一次切削し、環状溝１９を形成している。この環状溝１９の溝幅中央部にはボルト穴２０を円周方向等配に穿設している。さらにハブボルト１８の外径に形成したナール１８ａ部をこのボルト穴２０に圧入固定した後、側面４ａおよびパイロット部４ｂを旋盤により二次切削（仕上げ切削）している。二次切削は旋盤に限らず、フライス盤や研削盤による切削であっても良い。なお、ボルト穴２０は溝幅中央部に必ずしも穿設する必要はない。ここで、ハブボルト１８を車輪取付フランジ４に圧入するのは、ハブ輪１と外側継手部材１４とを塑性結合する前であっても、また後であっても良いが、車輪取付フランジ４の側面４ａの二次切削は最終的に装置をアッシーした後にするものとする。
【００３８】
図３は、車輪取付フランジ４の側面４ａに形成した環状溝１９部の要部拡大断面図である。この環状溝１９の溝幅寸法が大きければ、ハブボルト１８の圧入後の側面４ａにおける二次切削の作業性が向上するが、後述するブレーキロータ取付面との接触面積が減少し、ナット締結によって車輪取付フランジ４の側面４ａの変形が拡大して好ましくない。したがって、ハブボルト１８の外径から少なくとも環状溝１９までの寸法を１ｍｍとすれば、ブレーキロータ取付面との接触面積が大きく減少することはなく、車輪をナットで締結した時の側面４ａの変形を抑制し、ブレーキロータ側面の面振れ精度の悪化を最小限に抑制できることが判った。また、ハブボルト１８の外径から１ｍｍ以上の間隙があれば、旋削バイト等の加工治具Ｚが切削時に干渉して作業性を低下させることもない。
【００３９】
環状溝１９を側面４ａに形成することにより、ハブボルト１８の圧入による側面４ａへの変形等の影響を最小限に抑制できると共に、ハブボルト１８の圧入後、さらに側面４ａを二次切削すれば、ハブボルト１８の圧入によって増加した側面４ａの面振れを可及的に抑制することができる。
【００４０】
また、環状溝１９を側面４ａに形成せずに、ハブボルト１８の圧入後、側面４ａ、およびパイロット部４ｂをフライス盤、あるいは研削盤によって二次切削（仕上げ切削）すれば、ハブボルト１８の圧入によって増加した側面４ａの面振れを可及的に抑制すると共に、塑性結合によって拡径したパイロット部４ｂを修正することができる。
【００４１】
図４は、車輪取付フランジ４にブレーキロータ３０を取付けた状態を示す要部拡大断面図である。取付け部３１が車輪取付フランジ４の側面４ａと接触する接触面３１ａ、３１ｂを、ハブボルト１８のそれぞれ内外径側に両方に設けることにより、ナット（図示せず）締結による車輪取付フランジ４の変形を最小限に抑制できることが判った。
【００４２】
図５は、車輪取付フランジ４にブレーキロータ３０を取付けた状態を示す要部拡大断面図で、側面４ａにパイロット部４ｂまで続く環状溝１９’を形成している。この場合、取付け部３１が車輪取付フランジ４の側面４ａと外径側の接触面３１ｂのみで接触し、内径側の接触面３１ａとは接触しない。こうした状態で、ナットを締め付けると、ブレーキロータ３０における側面３２の面振れの変化は、図６に示すように、車輪取付フランジ４の傾きにより大きく変位し、さらに側面３２の面振れが悪化することが判った。
【００４３】
また、図４に示した状態から、車輪取付フランジ４の外径側を図示しない車輪側に僅かに傾斜等をさせて突出させ、ブレーキロータ３０の取付け部３１と車輪取付フランジ４の側面４ａを外径側で密着するようにすれば、ブレーキロータ３０の変形の自由度を拘束して、ブレーキロータ３０の面振れを抑制することができることも判った。段差は０．１ｍｍ以下（傾斜角度で最大１０’）で、これ以上突出させた場合は、前述したように、車輪取付フランジ４が傾き、ブレーキロータ３０の側面３２の面振れは悪化する。
【００４４】
次に、ブレーキロータ３０の側面３２の面振れ測定方法について説明する。図７は、車輪取付フランジ４にブレーキロータ３０を載置し、ナットを締結する前の状態、図８はナット締結後の状態を示す。
【００４５】
図７において、外方部材７の車体取付フランジ７ａを基台Ｂ上に載置し、内方部材８を回転自在に保持した上に、ブレーキロータ３０の取付け部３１を車輪取付フランジ４の側面４ａに密着させ、ブレーキロータ３０の側面３２にダイヤルゲージＧの触針を当接させる。ここで、内方部材８を回転させることにより、ブレーキロータ３０の側面３２の面振れを測定することができる。
【００４６】
図８において、ブレーキロータ３０の取付け部３１に、ホイールＷを密着させ、ハブボルト１８にナットＮを締結し、同様に、ブレーキロータ３０の側面３２にダイヤルゲージＧの触針を当接させた状態で内方部材１を回転させることにより、ブレーキロータ３０の側面３２の面振れを測定することができる。このように、本出願人は、ナットＮの締結前後において、ブレーキロータ３０の側面３２の面振れに及ぼす影響と要因を種々の条件で検証した。
【００４７】
図９は、車輪取付フランジ４にブレーキロータ３０とホイールＷを取付け、ナット（図示せず）を締結した状態を示す要部拡大断面図である。ここでホイールＷはプレス成形してなる鋼鈑製で、一般的にホイールの剛性アップのため、ハブボルト（図示せず）のピッチ円上に凹みＷａを設けている。これらの凹みＷａによって、ホイールＷとブレーキロータ３０とは全面接触するのではなく、円周上に部分接触することになる。一般的にアルミ合金等からなるホイールは、ブレーキロータとの接触部を切削面とし面精度は良いが、鋼鈑製ホイールＷはブレーキロータとの接触部の面精度が劣り、またナット締結によってさらにブレーキロータの側面における面振れを増加させる。
【００４８】
こうした鋼鈑製のホイールＷにおいても、このホイールＷのブレーキロータ３０との接触部のうち、ハブボルトのピッチ円直径に対して外径側の接触部３３ａよりも小径に、また、ハブボルトのピッチ円直径に対して内径側の接触部３３ｂよりも大径になるように、すなわち、両接触部３３ａ、３３ｂ間に環状溝１９が位置するように環状溝１９の幅寸法を設定すれば、ブレーキロータ３０の側面３２の面振れを抑制できることが判った。
【００４９】
しかし、図１０に示すように、環状溝１９”が両接触部３３ａ、３３ｂ到達するまで幅広になった場合、側面４ａの接触面積が不足して、ナット締結時に車輪取付フランジ４の変形を招来させ、ブレーキロータ３０の側面３２の面振れを悪化させることが判った。図１１、図１２はこうした環状溝の溝幅の違いによるブレーキロータ３０の側面３２の面振れへの影響を検証した結果を示すグラフで、図１１は、図９で説明したように、両接触部３３ａ、３３ｂ間に環状溝７が位置するように環状溝１９の幅寸法を設定した場合、図１２は、図１０で説明したように、環状溝１９”が両接触部３３ａ、３３ｂ到達するまで幅広になった場合、それぞれナット締結前後におけるブレーキロータ３０の側面３２の面振れを示している。
【００５０】
図１１で判るように、車輪リムＷの両接触部３３ａ、３３ｂ間に車輪取付フランジ４の環状溝１９が位置するように環状溝１９の幅寸法を設定した場合は、ナット締結により接触部３３ａ、３３ｂの密着度が向上して面振れが悪化しないが、図１２でも判るように、環状溝１９”が両接触部３３ａ、３３ｂに到達するまで幅広になった場合は、ブレーキロータ３０の側面３２の面振れは悪化する傾向が見られる。
【００５１】
前述した環状溝１９の深さは０．３ｍｍ以上、好ましくは０．４〜０．６ｍｍに設定すれば、環状溝１９の加工バラツキ、およびハブボルト１８の圧入後の切削加工バラツキを充分に許容することができる。
【００５２】
車輪取付フランジ４の側面４ａのうち、ブレーキロータ３０が接触する側の面振れを２０μｍ以下に規制すれば、ブレーキロータ３０取付後の側面３２の面振れ精度を５０μｍ以下に抑制することができることが判った。この側面３２の面振れが５０μｍを超えると操安性、すなわち、ブレーキジャダーが顕著になり、通常の運転者に不快感を生じさせて好ましくない。
【００５３】
以上本発明を、ハブ輪と複列の転がり軸受と等速自在継手とをユニット化し、複列の内側転走面のうち、アウトボード側の内側転走面をハブ輪の外周面に、また、インボード側の内側転走面を、等速自在継手の外側継手部材の外周面にそれぞれ直接形成した、所謂第４世代構造に適用した実施形態について説明したが、本発明はこの構造に限らず、ハブ輪に別体の内輪を圧入し、アウトボード側の軸受転走面をハブ輪に、また別体の内輪にインボード側の軸受転走面をそれぞれ形成した構造、所謂第３世代構造や、その他第１、第２世代構造の駆動車輪用軸受装置にも適用できる。
【００５４】
なお、車輪取付フランジ４の側面４ａを、予めハブボルト１８の圧入前に一次切削し、圧入後に二次切削をする実施形態について説明したが、本発明はこうした実施形態に限定されるものではなく、例えば、ハブボルト１８を圧入する前に、側面４ａを粗旋削と中仕上げ旋削からなる一次切削を行い、ハブボルト１８の圧入後に、二次切削（仕上げ切削）を行っても良い。また、ハブボルト１８の圧入前に切削を行わず、鍛造肌のままとし、ハブボルト１８の圧入後に二次切削（仕上げ切削）を行っても良い。
【００５５】
本発明は、こうした第１世代乃至第４世代構造の駆動車輪用軸受装置において適用が可能であると共に、それぞれの構造の特徴を失うことなく、車輪取付フランジの面振れ精度を高めてブレーキジャダーの発生を抑制し得る有効な手段と言える。
【００５６】
以上、本発明の実施の形態について説明を行ったが、本発明はこうした実施の形態に何等限定されるものではなく、あくまで例示であって、本発明の要旨を逸脱しない範囲内において、さらに種々なる形態で実施し得ることは勿論のことであり、本発明の範囲は、特許請求の範囲の記載によって示され、さらに特許請求の範囲に記載の均等の意味、および範囲内のすべての変更を含む。
【００５７】
【発明の効果】
以上詳述したように、本発明に係る駆動車輪用軸受装置は、塑性結合によりハブ輪と外側継手部材とを一体化したので、軽量・コンパクト化といった所期の技術課題を解決し、結合部の緩みや摩耗を防止することができる。これに加え、さらにハブボルトの圧入、およびハブ輪と外側継手部材の塑性結合後、すなわち、装置のアッシー後に切削加工する切削面（仕上げ切削面）としたことによって、塑性結合による車輪取付フランジの変形を修正し、さらにはハブボルト圧入等によるフランジ側面の面振れへの影響を抑制し、車輪取付フランジの側面の面振れ精度を高めてブレーキジャダーの発生を抑制することができる。また、第１世代乃至第４世代の駆動車輪用軸受装置において、それぞれの構造が有する特徴を失うことなく、簡単な構成で車輪取付フランジの側面の面振れ精度を高めることができる。
【図面の簡単な説明】
【図１】本発明に係る駆動車輪用軸受装置の実施形態を示す縦断面図である。
【図２】（ａ）は本発明に係るハブ輪の凹凸部形状を示す縦断面図で、互いに傾斜した螺旋溝で構成したアヤメローレット形状を示す。
（ｂ）は同上、軸方向、および独立した環状溝で構成したアヤメローレット形状を示す。
【図３】本発明に係る駆動車輪用軸受装置の要部拡大断面図である。
【図４】同上
【図５】本発明に係る駆動車輪用軸受装置と比較するための説明用要部拡大断面図である。
【図６】本発明に係る駆動車輪用軸受装置と比較するための説明用グラフである。
【図７】本発明に係る駆動車輪用軸受装置の面振れ測定方法を示す縦断面図である。
【図８】同上、ナット締結後の面振れ測定方法を示す縦断面図である。
【図９】本発明に係る駆動車輪用軸受装置の他の実施形態における要部拡大断面図である。
【図１０】同上と比較するための説明用要部拡大断面図である。
【図１１】本発明に係る駆動車輪用軸受装置の面振れ測定結果を示すグラフである。
【図１２】同上と比較するための説明用グラフである。
【図１３】（ａ）従来の駆動車輪用軸受装置を示す側面図である。
（ｂ）同上縦断面図である。
【図１４】従来の他の駆動車輪用軸受装置を示す縦断面図である。
【符号の説明】
１・・・・・・・・・・・・ハブ輪
１ａ・・・・・・・・・・・内側転走面
２・・・・・・・・・・・・複列の転がり軸受
３・・・・・・・・・・・・等速自在継手
４・・・・・・・・・・・・車輪取付フランジ
４ａ・・・・・・・・・・・側面
４ｂ・・・・・・・・・・・パイロット部
５・・・・・・・・・・・・凹凸部
６、６’・・・・・・・・・溝
７・・・・・・・・・・・・外方部材
７ａ・・・・・・・・・・・車体取付フランジ
７ｂ・・・・・・・・・・・外側転走面
８・・・・・・・・・・・・内方部材
９・・・・・・・・・・・・転動体
１０、１０’・・・・・・・硬化層
１１・・・・・・・・・・・保持器
１２、１３・・・・・・・・シール
１４・・・・・・・・・・・外側継手部材
１４ａ・・・・・・・・・・内側転走面
１５・・・・・・・・・・・マウス部
１５ａ・・・・・・・・・・トラック溝
１６・・・・・・・・・・・肩部
１７・・・・・・・・・・・軸部
１７ａ・・・・・・・・・・小径段部
１７ｂ・・・・・・・・・・嵌合部
１８・・・・・・・・・・・ハブボルト
１８ａ・・・・・・・・・・ナール
１９、１９’、１９”・・・環状溝
２０・・・・・・・・・・・ボルト穴
３０・・・・・・・・・・・ブレーキロータ
３１・・・・・・・・・・・取付け部
３１ａ、３１ｂ・・・・・・接触面
３２・・・・・・・・・・・側面
３３ａ、３３ｂ・・・・・・接触部
５０、９２・・・・・・・・内方部材
５１、８０・・・・・・・・ハブ輪
５１ａ、８０ａ・・・・・・転走面
５２・・・・・・・・・・・内輪
５２ａ・・・・・・・・・・転走面
５３・・・・・・・・・・・小径段部
５４、８１・・・・・・・・車輪取付フランジ
５４ａ・・・・・・・・・・側面
５５・・・・・・・・・・・ハブボルト
５５ａ・・・・・・・・・・ナール
５６・・・・・・・・・・・環状溝
５７・・・・・・・・・・・ボルト穴
６０、９１・・・・・・・・外方部材
６０ａ、６０ｂ、９１ａ・・転走面
６１、９４・・・・・・・・車体取付フランジ
６２、６３、９６、９７・・シール
７０、９３・・・・・・・・転動体
７１、９５・・・・・・・・保持器
Ｂ・・・・・・・・・・・・基台
Ｇ・・・・・・・・・・・・ダイヤルゲージ
Ｎ・・・・・・・・・・・・ナット
Ｗ・・・・・・・・・・・・ホイール
Ｗａ・・・・・・・・・・・凹み
Ｚ・・・・・・・・・・・・加工治具[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bearing device for a driving wheel that supports a driving wheel of an automobile or the like, and in particular, unitizes a hub wheel, a constant velocity universal joint, and a bearing portion, and improves surface runout accuracy of a wheel mounting flange. The present invention relates to a bearing device for a drive wheel that can suppress the occurrence of brake judder.
[0002]
[Prior art]
In general, disc brakes with excellent braking power have become widespread, but when braking with the disc brake rotor held between brake pads, vibration occurs especially when the vehicle is running at low speed, causing unpleasant noise at low frequencies. There are things to do. Such a phenomenon is called a brake judder, and in recent years, this analysis and improvement has attracted attention as a new technical problem as the performance and quietness of the vehicle are improved.
[0003]
The exact mechanism of the brake judder has not yet been elucidated in detail, but one factor is the accuracy of the pad sliding contact surface of the brake rotor. This runout accuracy includes not only the runout accuracy of the brake rotor itself, but also the runout accuracy of the wheel mounting flange to which the brake rotor is mounted, the axial runout of the rolling bearing, and the assembly accuracy of the rolling bearing. Finally, the surface runout accuracy of the brake rotor side surface appears.
[0004]
In recent years, not only cost reduction, but also a constant velocity universal joint, a hub wheel, and a bearing portion tend to be unitized for the purpose of weight reduction and compactness in order to improve fuel consumption. As a result, the drive wheel bearing device is slimmed down as much as possible by eliminating surplus. On the other hand, it is indispensable to increase the rigidity of the device for the steering stability of the vehicle. While satisfying such contradictory requirements, the above-described countermeasures for surface runout accuracy of the brake rotor side surface are taken.
[0005]
FIG. 13 shows a conventional drive wheel bearing device, in which (b) is a longitudinal sectional view and (a) is a side view thereof. In the following description, the side closer to the outside of the vehicle in the state assembled to the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing).
[0006]
This drive wheel bearing device includes an inner member 50, an outer member 60, and double row rolling elements 70, 70. The inner member 50 includes a hub ring 51 and a separate inner ring 52, and the inner ring 52 is press-fitted into a small diameter step portion 53 formed at the inboard side end of the hub ring 51. An outboard-side rolling surface 51 a is formed on the outer periphery of the hub wheel 51, and an inboard-side rolling surface 52 a is formed on the outer periphery of the inner ring 52. Further, the hub wheel 51 integrally has a wheel mounting flange 54 for mounting a wheel (not shown) at an end portion on the outboard side, and the wheel mounting flange 54 is for fixing the wheel at a circumferentially equidistant position. Hub bolts 55 are planted.
[0007]
On the other hand, the outer member 60 integrally has a vehicle body mounting flange 61 for mounting a vehicle body (not shown) on the outer periphery, and integrally forms double-row rolling surfaces 60a and 60b on the inner periphery. Between these rolling surfaces 60a, 60b and the above-described rolling surfaces 51a, 52a, double-row rolling elements (balls) 70, 70, which are circumferentially arranged by cages 71, 71, are respectively accommodated so as to freely roll. Yes.
[0008]
Seals 62 and 63 are attached to both ends of the outer member 60, the annular space between the outer member 60 and the inner member 50 is sealed, and leakage of the lubricating grease enclosed in the bearing is prevented, and rainwater from the outside And intrusion of dust and the like. Here, the inner member 50 refers to the hub wheel 51 and the inner ring 52.
[0009]
An annular groove 56 is formed in the side surface 54 a of the wheel mounting flange 54, and bolt holes 57 are bored in the annular groove 56 at equal intervals in the circumferential direction. A knurl 55a formed on the outer diameter of the hub bolt 55 is press-fitted and fixed in the bolt hole 57, and a nut (not shown) is screwed to fasten a wheel via a brake rotor (not shown).
[0010]
Since the bolt hole 57 is formed in the annular groove 56, deformation of the periphery of the bolt hole 57 and undulation generated on the side surface 54a of the wheel mounting flange 54 due to the press-fitting of the hub bolt 55 can be kept in the annular groove 56. The influence on the side surface 54a outside the annular groove 56 is suppressed (see Japanese Patent Laid-Open No. 7-164809).
[0011]
In the drive wheel bearing device shown in FIG. 14, the hub wheel 80, the bearing portion 90, and the constant velocity universal joint 100 are configured as a unit. The hub wheel 80 integrally has a wheel mounting flange 81 for mounting a wheel (not shown), and a hub bolt 82 for fixing the wheel is implanted at a circumferentially equidistant position of the wheel mounting flange 81. Yes.
[0012]
The bearing portion 90 includes an outer member 91, an inner member 92, and double-row rolling elements 93, 93. The outer member 91 is integrally provided with a vehicle body mounting flange 94 for mounting to a vehicle body (not shown) on the outer periphery. And has double rows of rolling surfaces 91a, 91a on the inner periphery. On the other hand, the inner member 92 is formed with double-row rolling surfaces 80a and 101a facing the rolling surfaces 91a and 91a of the outer member 91 described above. Of these double-row rolling surfaces 80a and 101a, the rolling surface 80a on the outboard side is the outer periphery of the hub wheel 80, and the rolling surface 101a on the inboard side is the outer periphery of the outer joint member 101 of the constant velocity universal joint 100. Are integrally formed. Double-row rolling elements 93 and 93 are accommodated between these rolling surfaces 91a and 80a and 91a and 101a, and are held by rollers 95 and 95 so that they can roll freely. In this case, the inner member 92 refers to the hub wheel 80 and the outer joint member 101. Seals 96 and 97 are attached to the end portion of the bearing portion 90 to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater and dust from the outside.
[0013]
The constant velocity universal joint 100 includes an outer joint member 101, a joint inner ring, a cage, and a torque transmission ball (not shown). The outer joint member 101 includes a cup-shaped mouth portion 102 and a shaft portion extending in the axial direction from the mouth portion 102. 103, and a curved track groove 102a extending in the axial direction is formed on the inner periphery of the mouse portion 102.
[0014]
Here, the shaft portion 103 of the outer joint member 101 formed in a hollow shape is fitted into the hub wheel 80, and an unevenness 83 is formed on the inner peripheral surface of the hub wheel 80. The hub wheel 80 and the outer joint member 101 are plastically coupled by biting into the 83 and the fitting portion thereof is swaged (see JP-A-2001-18605).
[0015]
In such a drive wheel bearing device, the loosening and wear of the fitting portion can be suppressed as compared with the conventional torque transmission means such as serrations, and the coupling portion includes the torque transmission means, the hub wheel and the outer joint member coupling means. Can be further reduced in weight and size.
[0016]
[Problems to be solved by the invention]
However, in the former drive wheel bearing device described above, the annular groove 56 is formed in the side surface 54a of the wheel mounting flange 54, and the hub bolt 55 is press-fitted after that. It was difficult and there was a limit to improving the surface runout accuracy of the side surface 54a. In particular, in the case of a steel wheel formed by press working, the accuracy of the mounting surface is worse than that of an aluminum alloy wheel formed by cutting, and depending on the depth and width dimension of the annular groove 56, the wheel is attached by tightening a nut. In some cases, the flange 54 is inclined, and the surface runout accuracy of the side surface (pad sliding contact surface) of the brake rotor is deteriorated.
[0017]
Therefore, by simply forming the annular groove 56 on the side surface 54a of the wheel mounting flange 54 and drilling the bolt hole 57 into the annular groove 56, the influence on the side surface 54a due to the press-fitting of the hub bolt 55 can be completely prevented. It was difficult, and there was still some room for improvement to improve the surface runout accuracy on the side of the brake rotor.
[0018]
Further, in the latter bearing device for a drive wheel, the diameter of the shaft portion 103 is increased and the pilot portion 84 that guides the brake rotor (not shown) is increased in diameter so that it is difficult to mount the brake rotor. However, it was found that the shaft portion 103 extended to the outboard side and the wheel mounting flange 81 tilted to the inboard side. These deformation amounts vary depending on the caulking conditions and the like, and it is difficult to predict and set the deformation amounts in advance. As a result, it has been found that the surface runout of the side surface of the wheel mounting flange 81 is deteriorated.
[0019]
The present invention has been made in view of such circumstances, and provides a drive wheel bearing device that achieves lightening and compactness by unitizing the device and improving the surface runout accuracy of the side surface of the brake rotor. The purpose is that.
[0020]
[Means for Solving the Problems]
  In order to achieve such an object, the invention according to claim 1 of the present invention forms a wheel mounting flange for fastening a wheel via a brake rotor, and a plurality of hub bolts are implanted along the circumferential direction of the wheel mounting flange. The hub wheel to be installed, the constant velocity universal joint, and the double row rolling bearing that rotatably supports the wheel with respect to the vehicle body are unitized, and the hub wheel and the outer joint member of the constant velocity universal joint are fitted, In the drive wheel bearing device configured to transmit the rotation of the constant velocity universal joint to the hub wheel,An annular groove having a predetermined width including the hub bolt is formed on the wheel mounting flange, and the contact surface on the outer diameter side of the wheel mounting flange is set on the wheel side with respect to the contact surface on the inner diameter side of the wheel mounting flange. To slightly projectOf the hub wheelOf the part where the wheel mounting flange is providedThe outer joint member has a shape in which a plurality of rows of grooves are orthogonal to the inner diameter, and a cured uneven portion is formed.Shaft partThe hub wheel and the outer joint member are integrally plastically joined by enlarging the diameter of the wheel, and the hub bolt is press-fitted into the side surface of the wheel mounting flange.The hub wheel and the outer joint member are integrated.A configuration was adopted in which the cutting surface was cut after plastic bonding.
[0021]
  In this way, the hub wheel and the outer joint member are integrally plastically bonded, and further, after the hub bolt press-fitting and the plastic coupling, that is, after assembly, the side surface of the wheel mounting flange is finished by turning or the like. Compared with conventional torque transmission means such as serrations, loosening and wear of the fitting part can be suppressed, and light weight and compactness can be achieved. At the same time, deformation of the wheel mounting flange caused by plastic coupling and flange side face by hub bolt press-fitting The influence on the surface runout accuracy can be substantially reduced to zero.Further, by slightly projecting the outer diameter side of the wheel mounting flange toward the wheel side, the brake rotor and the wheel mounting flange are brought into close contact with each other on the outer diameter side, and the degree of freedom of deformation of the brake rotor is constrained. Surface deflection can be suppressed.

[0022]
In the invention according to claim 2, since the pilot portion of the brake rotor formed on the hub wheel is a cutting surface that is cut after plastic coupling, the brake rotor can be easily formed even if the pilot portion is expanded in diameter by plastic coupling. Can be worn.
[0023]
Further, as in the invention described in claim 3, the wheel mounting flange is formed with an annular groove having a predetermined width including the hub bolt, and the side surface of the wheel mounting flange other than the annular groove is cut after the hub bolt press-fitting. If the cut surface (finished cut surface) is used, finishing can be performed by simple turning, and the cost can be reduced by reducing the number of work steps.
[0024]
When the wheel of the wheel is made of steel as in the invention described in claim 4, the contact portion between the wheel and the brake rotor is more than the contact portion on the outer diameter side with respect to the pitch circle diameter of the hub bolt. Since the width of the annular groove is set so that it has a smaller diameter and a larger diameter than the contact part on the inner diameter side with respect to the pitch circle diameter of the hub bolt, the press is said to have relatively poor accuracy of the mounting part. Even with a steel-steel wheel formed by molding, the surface runout accuracy of the brake rotor side surface can be suppressed to a desired specified value.
[0025]
Preferably, as in the invention described in claim 5, the hub bolt is implanted in the annular groove, and the distance from the outer diameter of the hub bolt to the edge of the annular groove is set to 1 mm or more. While allowing a deformation | transformation, the workability | operativity of the finishing process of a flange side surface can be improved.
[0026]
More preferably, when the depth of the annular groove is at least 0.3 mm as in the invention described in claim 6, it is possible to sufficiently allow the machining variation of the annular groove and the cutting variation after the hub bolt press-fitting. it can.
[0028]
  Claims7If the surface runout on the side contacting the brake rotor is restricted to 20 μm or less among the side surfaces of the wheel mounting flange as in the invention described in 1), the surface runout accuracy on the side surface of the brake rotor can be suppressed to a desired specified value. it can.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a drive wheel bearing device according to the present invention. This drive wheel bearing device comprises a hub wheel 1, a double row rolling bearing 2 and a constant velocity universal joint 3 as a unit. In the following description, the side closer to the outside of the vehicle in the state assembled to the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing).
[0030]
The hub wheel 1 integrally has a wheel mounting flange 4 for mounting a wheel (not shown) at an end portion on the outboard side, and the wheel is fixed at a circumferentially equidistant position of the wheel mounting flange 4. The hub bolt 18 is planted. Concave and convex portions 5 are formed on the inner peripheral surface of the hub wheel 1, and the hardened layer 10 is formed with a surface hardness in the range of 54 to 64 HRC by heat treatment (indicated by a dotted pattern in the figure). As the heat treatment, local heating is preferable, and quenching by high-frequency induction heating that can set the hardened layer depth relatively easily is preferable. In addition, the uneven | corrugated | grooved part 5 can illustrate the shape which orthogonally crossed the groove | channel of several rows as shown in FIG. (A) is a spiral groove 6 inclined with respect to each other, and (b) can be formed in an iris knurl shape in the axial direction and with an independent annular groove 6 ′. Further, the convex portion of the concave and convex portion 5 is formed in a pointed shape such as a triangular shape in order to ensure good biting property.
[0031]
The double-row rolling bearing 2 includes an outer member 7, an inner member 8, and double-row rolling elements 9, 9. The outer member 7 is a vehicle body mounting flange for mounting to the vehicle body (not shown) on the outer periphery. 7a is integrally formed, and double row outer rolling surfaces 7b and 7b are formed on the inner periphery. On the other hand, the inner member 8 refers to the hub wheel 1 and an outer joint member 14 to be described later. The inner rolling surface 1a on the outboard side facing the outer rolling surfaces 7b and 7b of the outer member 7 is connected to the hub wheel 1. An inner rolling surface 14a on the inboard side is formed on the outer periphery and on the outer periphery of the outer joint member 14, respectively. Double row rolling elements 9, 9 are accommodated between the rolling surfaces 7b, 1a and 7b, 14a, respectively, and are held by the retainers 11, 11 so as to be freely rollable. Seals 12 and 13 are attached to the ends of the double-row rolling bearing 2 to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater and dust from the outside.
[0032]
On the outer periphery of the hub wheel 1, the hardened layer 10 ′ is induction-hardened on the surfaces of the seal land portion in which the seal lip of the seal 12 is in sliding contact, the inner rolling surface 1 a, and the inrow portion 1 b in contact with the shoulder 16 of the outer joint member 14. (Indicated by a dotted pattern in the figure). Here, the double-row rolling bearing 2 is exemplified as a double-row angular ball bearing in which the rolling elements 9 and 9 are balls. However, the double-row rolling bearing 2 is not limited to this and may be a double-row tapered roller bearing using a tapered roller as the rolling element. .
[0033]
The constant velocity universal joint 3 includes an outer joint member 14, a joint inner ring (not shown), a cage, and a torque transmission ball. The outer joint member 14 has a cup-shaped mouth portion 15, a shoulder portion 16 that forms the bottom portion of the mouth portion 15, and a shaft portion 17 that extends from the shoulder portion 16 in the axial direction. A curved track groove 15a extending in the axial direction is formed.
[0034]
The inner rolling surface 14a is formed on the outer periphery of the shoulder 16 of the outer joint member 14 formed in a hollow shape. The shaft portion 17 has a small-diameter step portion 17 a for press-fitting the in-row portion 1 b of the hub wheel 1 and a fitting portion 17 b for fitting with the hub wheel 1. The inrow portion 1b of the hub wheel 1 press-fitted into the small-diameter step portion 17a is abutted by the shoulder portion 16, the fitting portion 17b is fitted into the hub wheel 1, and a mandrel is inserted into and removed from the inner diameter of the fitting portion 17b. For example, the fitting portion 17b is expanded in diameter by an appropriate means so as to bite into the uneven portion 5 of the hub wheel 1, and the fitting portion 17b is crimped to plastically connect the hub wheel 1 and the outer joint member 14. . As a result, since this coupling portion has both the torque transmission means and the coupling means for the hub wheel 1 and the outer joint member 14, it is necessary to form a conventional torque transmission means such as serration on the hub wheel 1 or the outer joint member 14. In addition, a fixing means such as a fastening nut is not necessary, and the apparatus can be further reduced in weight and size.
[0035]
In the outer joint member 14, the surface hardening treatment is performed over the rolling surface 14 a and the small diameter step portion 17 a from the seal land portion in which the track groove 15 a formed on the inner periphery of the mouth portion 15 and the seal 13 are in sliding contact. Quenching by high frequency induction heating is suitable as the curing treatment. Moreover, the fitting part 17b whose diameter is expanded is an unquenched part with a material surface hardness of 24 HRC or less after forging, and the hardness difference between the surface hardness 54 to 64 HRC of the uneven part 5 of the hub wheel 1 is 30 HRC or more. It is preferable to set. Thereby, the fitting part 17b can bite into the uneven | corrugated | grooved part 5 easily and deeply, and both can be firmly plastic-bonded without the front-end | tip of the uneven | corrugated | grooved part 5 being crushed.
[0036]
Although not shown, an end cap is attached to the inner diameter of the hollow outer joint member 14 to prevent leakage of the lubricating grease sealed in the mouth portion 15 to the outside and intrusion of dust from the outside.
[0037]
In the present embodiment, the side surface 4a of the wheel mounting flange 4 is primarily cut by a lathe or the like to form the annular groove 19. Bolt holes 20 are formed in the center of the groove width of the annular groove 19 at equal intervals in the circumferential direction. Further, after a knurl 18a portion formed on the outer diameter of the hub bolt 18 is press-fitted and fixed in the bolt hole 20, the side surface 4a and the pilot portion 4b are subjected to secondary cutting (finish cutting) with a lathe. Secondary cutting is not limited to a lathe, and may be cutting with a milling machine or a grinding machine. The bolt hole 20 does not necessarily need to be drilled in the central portion of the groove width. Here, the hub bolt 18 may be press-fitted into the wheel mounting flange 4 before or after the hub wheel 1 and the outer joint member 14 are plastically coupled. The secondary cutting of 4a shall be performed after the apparatus is finally assembled.
[0038]
FIG. 3 is an enlarged cross-sectional view of the main part of the annular groove 19 formed on the side surface 4 a of the wheel mounting flange 4. If the groove width dimension of the annular groove 19 is large, the workability of secondary cutting on the side surface 4a after the press-fitting of the hub bolt 18 is improved, but the contact area with the brake rotor mounting surface, which will be described later, is reduced. The deformation of the side surface 4a of the mounting flange 4 is not preferable because it expands. Therefore, if the dimension from the outer diameter of the hub bolt 18 to at least the annular groove 19 is 1 mm, the contact area with the brake rotor mounting surface will not be greatly reduced, and the deformation of the side surface 4a when the wheel is fastened with a nut will be prevented. It was found that the deterioration of the runout accuracy on the side surface of the brake rotor can be minimized. Further, if there is a gap of 1 mm or more from the outer diameter of the hub bolt 18, the work jig Z such as a turning tool will not interfere with the cutting and the workability will not be lowered.
[0039]
By forming the annular groove 19 on the side surface 4a, the influence of the deformation of the hub bolt 18 on the side surface 4a due to the press-fitting of the hub bolt 18 can be suppressed to the minimum. The surface runout of the side surface 4a increased by the 18 press-fitting can be suppressed as much as possible.
[0040]
Further, if the side surface 4a and the pilot portion 4b are subjected to secondary cutting (finish cutting) with a milling machine or a grinding machine after the hub bolt 18 is press-fitted without forming the annular groove 19 on the side face 4a, the increase is caused by press-fitting of the hub bolt 18. It is possible to suppress the runout of the side surface 4a as much as possible, and to correct the pilot portion 4b whose diameter has been expanded by plastic coupling.
[0041]
FIG. 4 is an enlarged cross-sectional view of a main part showing a state where the brake rotor 30 is attached to the wheel attachment flange 4. By providing contact surfaces 31a and 31b on the inner and outer diameter sides of the hub bolt 18 so that the mounting portion 31 contacts the side surface 4a of the wheel mounting flange 4, the deformation of the wheel mounting flange 4 by tightening a nut (not shown) can be achieved. It was found that it can be minimized.
[0042]
FIG. 5 is an enlarged cross-sectional view of a main part showing a state in which the brake rotor 30 is attached to the wheel attachment flange 4, and an annular groove 19 'extending to the pilot part 4b is formed on the side face 4a. In this case, the attachment portion 31 is in contact with only the side surface 4a of the wheel attachment flange 4 and the contact surface 31b on the outer diameter side, and is not in contact with the contact surface 31a on the inner diameter side. When the nut is tightened in such a state, the change in the surface runout of the side surface 32 in the brake rotor 30 is largely displaced by the inclination of the wheel mounting flange 4 as shown in FIG. I understood.
[0043]
Further, from the state shown in FIG. 4, the outer diameter side of the wheel mounting flange 4 is protruded by slightly inclining or the like to the wheel side (not shown), and the mounting portion 31 of the brake rotor 30 and the side surface 4a of the wheel mounting flange 4 are It has also been found that if close contact is made on the outer diameter side, the degree of freedom of deformation of the brake rotor 30 can be constrained, and surface deflection of the brake rotor 30 can be suppressed. The step is 0.1 mm or less (maximum 10 'in inclination angle), and if it is projected beyond this, as described above, the wheel mounting flange 4 is inclined and the surface runout of the side surface 32 of the brake rotor 30 is deteriorated.
[0044]
Next, a method for measuring the surface runout of the side surface 32 of the brake rotor 30 will be described. FIG. 7 shows a state before the brake rotor 30 is mounted on the wheel mounting flange 4 and the nut is fastened, and FIG. 8 shows a state after the nut is fastened.
[0045]
In FIG. 7, the vehicle body mounting flange 7 a of the outer member 7 is placed on the base B, the inner member 8 is rotatably held, and the mounting portion 31 of the brake rotor 30 is attached to the side surface of the wheel mounting flange 4. The stylus of the dial gauge G is brought into contact with the side surface 32 of the brake rotor 30. Here, the surface runout of the side surface 32 of the brake rotor 30 can be measured by rotating the inner member 8.
[0046]
In FIG. 8, the wheel W is brought into close contact with the mounting portion 31 of the brake rotor 30, the nut N is fastened to the hub bolt 18, and the dial gauge G stylus is in contact with the side surface 32 of the brake rotor 30. By rotating the inner member 1, the runout of the side surface 32 of the brake rotor 30 can be measured. As described above, the present applicant verified the influence and factors on the runout of the side surface 32 of the brake rotor 30 under various conditions before and after the nut N was fastened.
[0047]
FIG. 9 is an enlarged cross-sectional view of a main part showing a state where the brake rotor 30 and the wheel W are attached to the wheel attachment flange 4 and a nut (not shown) is fastened. Here, the wheel W is made of a steel plate formed by press molding, and generally, a recess Wa is provided on a pitch circle of a hub bolt (not shown) in order to increase the rigidity of the wheel. Due to these recesses Wa, the wheel W and the brake rotor 30 do not make full contact, but make partial contact on the circumference. In general, a wheel made of an aluminum alloy or the like has a good surface accuracy with the contact portion with the brake rotor as a cutting surface, but the steel-steel wheel W has a poor surface accuracy with the contact portion with the brake rotor, and is further increased by tightening a nut. Increases runout on the side of the brake rotor.
[0048]
Also in such a steel-steel wheel W, the contact portion of the wheel W with the brake rotor 30 has a smaller diameter than the contact portion 33a on the outer diameter side with respect to the pitch circle diameter of the hub bolt, and the pitch circle of the hub bolt. If the width dimension of the annular groove 19 is set so that the diameter is larger than the diameter of the contact portion 33b on the inner diameter side, that is, the annular groove 19 is positioned between the contact portions 33a and 33b, the brake rotor It was found that the surface runout of the side surface 32 of 30 can be suppressed.
[0049]
However, as shown in FIG. 10, when the annular groove 19 ″ becomes wide until it reaches both contact portions 33a and 33b, the contact area of the side surface 4a is insufficient, and the wheel mounting flange 4 is deformed when the nut is fastened. As a result, it was found that the surface runout of the side surface 32 of the brake rotor 30 deteriorated, and FIGS.11 and 12 show the results of verifying the influence on the surface runout of the side surface 32 of the brake rotor 30 due to the difference in the groove width of the annular groove. FIG. 11 is a graph showing the case where the width of the annular groove 19 is set so that the annular groove 7 is positioned between the contact portions 33a and 33b, as described in FIG. As described above, when the annular groove 19 ″ becomes wider until it reaches both contact portions 33a and 33b, the runout of the side surface 32 of the brake rotor 30 before and after the nut fastening is shown.
[0050]
As can be seen from FIG. 11, when the width dimension of the annular groove 19 is set so that the annular groove 19 of the wheel mounting flange 4 is positioned between both contact parts 33a and 33b of the wheel rim W, the contact part 33a is fastened with a nut. 33b is improved, and the runout does not deteriorate. However, as can be seen in FIG. 12, when the annular groove 19 ″ becomes wide until it reaches both contact portions 33a and 33b, the side surface of the brake rotor 30 is increased. There is a tendency for the surface runout of 32 to get worse.
[0051]
If the depth of the annular groove 19 described above is set to 0.3 mm or more, preferably 0.4 to 0.6 mm, the machining variation of the annular groove 19 and the machining variation after press-fitting of the hub bolt 18 are sufficiently allowed. be able to.
[0052]
If the surface runout of the side surface 4a of the wheel mounting flange 4 that contacts the brake rotor 30 is restricted to 20 μm or less, the surface runout accuracy of the side surface 32 after the brake rotor 30 is mounted can be suppressed to 50 μm or less. understood. When the surface runout of the side surface 32 exceeds 50 μm, the operability, that is, the brake judder becomes conspicuous, which causes an uncomfortable feeling to a normal driver.
[0053]
As described above, the present invention unitizes the hub wheel, the double row rolling bearing, and the constant velocity universal joint, and of the double row inner rolling surface, the inner rolling surface on the outboard side is the outer peripheral surface of the hub wheel. The embodiment applied to the so-called fourth generation structure in which the inner rolling surface on the inboard side is directly formed on the outer peripheral surface of the outer joint member of the constant velocity universal joint has been described, but the present invention is not limited to this structure. First, a separate inner ring is press-fitted into the hub wheel, the bearing rolling surface on the outboard side is formed on the hub ring, and the bearing rolling surface on the inboard side is formed on the separate inner ring, so-called third generation. The present invention can also be applied to structures and other first and second generation drive wheel bearing devices.
[0054]
In addition, although embodiment which cuts the side surface 4a of the wheel mounting flange 4 in advance before press-fitting the hub bolt 18 and performs secondary cut after press-fitting has been described, the present invention is not limited to such an embodiment, For example, the primary cutting including rough turning and intermediate finishing turning may be performed on the side surface 4a before press-fitting the hub bolt 18, and the secondary cutting (finish cutting) may be performed after press-fitting the hub bolt 18. Further, the cutting may not be performed before press-fitting the hub bolt 18, and the forged skin may be left as it is, and the secondary cutting (finish cutting) may be performed after the press-fitting of the hub bolt 18.
[0055]
The present invention can be applied to the drive wheel bearing device of the first generation to the fourth generation structure, and the surface runout accuracy of the wheel mounting flange can be improved without losing the characteristics of each structure, so that the brake judder can be used. It can be said that it is an effective means that can suppress the occurrence.
[0056]
The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.
[0057]
【The invention's effect】
As described above in detail, the drive wheel bearing device according to the present invention integrates the hub wheel and the outer joint member by plastic coupling, thereby solving the expected technical problem such as light weight and compactness. Can be prevented from loosening and wearing. In addition to this, deformation of the wheel mounting flange due to plastic connection is achieved by further pressing the hub bolt and plastic cutting between the hub wheel and the outer joint member, that is, the cutting surface (finish cutting surface) to be cut after assembly of the device. Further, it is possible to suppress the influence of the hub bolt press-fitting etc. on the surface runout of the flange side surface, and to improve the surface runout accuracy of the side surface of the wheel mounting flange, thereby suppressing the occurrence of brake judder. Further, in the first to fourth generation drive wheel bearing devices, the surface runout accuracy of the side surface of the wheel mounting flange can be increased with a simple configuration without losing the characteristics of each structure.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a bearing device for a drive wheel according to the present invention.
FIG. 2 (a) is a longitudinal sectional view showing the shape of an uneven portion of a hub wheel according to the present invention, showing an iris knurl shape formed by spiral grooves inclined with respect to each other.
(B) shows the same shape as above, the axial direction, and the iris knurl shape formed by independent annular grooves.
FIG. 3 is an enlarged cross-sectional view of a main part of a drive wheel bearing device according to the present invention.
[Fig. 4] Same as above
FIG. 5 is an enlarged cross-sectional view of a main part for explanation for comparison with a drive wheel bearing device according to the present invention.
FIG. 6 is an explanatory graph for comparison with a drive wheel bearing device according to the present invention.
FIG. 7 is a longitudinal sectional view showing a method of measuring surface runout of a drive wheel bearing device according to the present invention.
FIG. 8 is a longitudinal sectional view showing a method of measuring surface runout after nut fastening.
FIG. 9 is an enlarged cross-sectional view of a main part in another embodiment of the drive wheel bearing device according to the present invention.
FIG. 10 is an enlarged cross-sectional view of a main part for explanation for comparison with the above.
FIG. 11 is a graph showing the results of surface runout measurement of the drive wheel bearing device according to the present invention.
FIG. 12 is an explanatory graph for comparison with the above.
FIG. 13 (a) is a side view showing a conventional drive wheel bearing device.
(B) It is a longitudinal cross-sectional view same as the above.
FIG. 14 is a longitudinal sectional view showing another conventional drive wheel bearing device.
[Explanation of symbols]
1 ・・・・・・・・・・・ Hub wheel
1a ・・・・・・・・・・・ Inner rolling surface
2 ..... Double row rolling bearing
3 ・・・・・・・・・・・ Constant velocity universal joint
4 ..... Wheel mounting flange
4a ・・・・・・・・・・・ Side
4b ... Pilot part
5 ・・・・・・・・・・・・ Unevenness
6, 6 '... groove
7 ······ Outer member
7a ... Body mounting flange
7b ............ Outer rolling surface
8 ..... Inner member
9 ..... rolling element
10, 10 '.... Hardened layer
11 ・・・・・・・・・・・ Retainer
12, 13, ... Seal
14 ・・・・・・・・・・・ Outer joint member
14a ... Inward rolling surface
15 ..... Mouse part
15a: Track groove
16 ... shoulder
17 ・・・・・・・・・・・ Shaft
17a ... Small diameter step
17b ..... fitting part
18 ・・・・・・・・・・・ Hub Bolt
18a …… Nar
19, 19 ', 19 "... annular groove
20 ・・・・・・・・・・・ Bolt hole
30 ・・・・・・・・・・・ Brake rotor
31 ・・・・・・・・・・・ Mounting part
31a, 31b ... Contact surface
32 ・・・・・・・・ Side
33a, 33b ・・・・・・ Contact part
50, 92 ..... Inner member
51, 80 ... hub wheel
51a, 80a ... Rolling surface
52 ..... Inner ring
52a ... Rolling surface
53 ・・・・・・・・・・・ Small diameter step
54, 81... Wheel mounting flange
54a side
55 ..... Hub bolt
55a …… Nar
56 ・・・・・・・・・・・ annular groove
57 ・・・・・・・・・・・ Bolt hole
60, 91... Outer member
60a, 60b, 91a ... rolling surface
61, 94 ..... Body mounting flange
62, 63, 96, 97 .. seal
70, 93 ... Rolling elements
71, 95 ... ・・・・・ Retainer
B ・・・・・・・・・・・ Base
G ... Dial Gauge
N ......... Nut
W ......... Wheel
Wa ····················
Z ... Processing jig

Claims

A wheel mounting flange that fastens the wheel via the brake rotor is formed, and a hub wheel in which a plurality of hub bolts are installed along the circumferential direction of the wheel mounting flange, a constant velocity universal joint, and the wheel is rotated with respect to the vehicle body. A double-row rolling bearing that is freely supported is unitized, and the hub wheel and the outer joint member of the constant velocity universal joint are fitted together to transmit the rotation of the constant velocity universal joint to the hub wheel. In the drive wheel bearing device,
An annular groove having a predetermined width including the hub bolt is formed on the wheel mounting flange, and the contact surface on the outer diameter side of the wheel mounting flange is set on the wheel side with respect to the contact surface on the inner diameter side of the wheel mounting flange. A plurality of grooves are orthogonal to the inner diameter of the portion of the hub wheel where the wheel mounting flange is provided to form a hardened concave and convex portion. The hub wheel and the outer joint member are integrally plastically joined by enlarging the shaft portion of the outer joint member, and the side surface of the wheel mounting flange is press-fitted with the hub bolt and the hub wheel. A bearing device for a drive wheel, wherein the outer joint member is a cutting surface that is cut after plastic bonding.

The bearing device for a drive wheel according to claim 1, wherein a pilot portion of a brake rotor formed on the hub wheel is a cutting surface that is cut after the plastic coupling.

An annular groove having a predetermined width including the hub bolt is formed in the wheel mounting flange, and a side surface of the wheel mounting flange other than the annular groove is a cutting surface cut after the hub bolt press-fitting. 3. A drive wheel bearing device according to 2.

When the wheel of the wheel is made of steel, the contact diameter between the wheel and the brake rotor is smaller than the contact diameter on the outer diameter side with respect to the pitch diameter of the hub bolt, and the pitch circle of the hub bolt. The bearing device for a drive wheel according to claim 3, wherein a width dimension of the annular groove is set so as to be larger than a contact portion on an inner diameter side with respect to a diameter.

The drive wheel bearing device according to claim 3 or 4, wherein the hub bolt is implanted in the annular groove, and a distance from an outer diameter of the hub bolt to an edge of the annular groove is 1 mm or more.

The drive wheel bearing device according to any one of claims 3 to 5, wherein a depth of the annular groove is at least 0.3 mm.

The bearing apparatus for drive wheels of any one of Claims 1 thru | or 6 which controlled the surface runout of the side which the said brake rotor contacts among the side surfaces of the said wheel mounting flange to 20 micrometers or less.