JP3962187B2

JP3962187B2 - Wheel bearing device

Info

Publication number: JP3962187B2
Application number: JP26903799A
Authority: JP
Inventors: 基晴仁木; 英児田島
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 1999-09-22
Filing date: 1999-09-22
Publication date: 2007-08-22
Anticipated expiration: 2019-09-22
Also published as: JP2001088510A

Description

【０００１】
【発明の属する技術分野】
本発明は車輪軸受装置に関し、詳しくは、自動車に用いられ、軸受剛性の向上を図り得る車輪軸受装置に関する。
【０００２】
【従来の技術】
図４は自動車に用いられる車輪軸受装置の一例で、従動輪用として用いた場合の構造を示す。この軸受装置は、ハブ輪１を車軸軸受２によって回転自在に支持した構造を有し、そのハブ輪１に車輪ホイールが固定され、車軸軸受２をナックル３を介して車体の懸架装置によって支持する。
【０００３】
車軸軸受２は、複列転がり軸受であって、内径面に複列の軌道面４，５が形成された外輪６と、外径面に軌道面７，８が形成された内輪９，１０と、外輪６と内輪９，１０との間に介在させた複列の転動体１１と、各列の転動体１１を円周方向等間隔に支持する保持器１２とで構成される。
【０００４】
外輪６はナックル３に圧入されて止め輪１３で固定されている。車軸軸受２に対して外部からの異物の侵入や内部に充填したグリースの漏出を防止するため、シール１４，１５が設けられている。図示の例では、車軸軸受２として複列アンギュラ玉軸受が使用されている。
【０００５】
ハブ輪１はフランジ１６を備え、このフランジ１６の円周方向等間隔位置に車輪ホイールを固定するためのハブボルト１７が取り付けられている。また、ハブ輪１のフランジ１６には、ブレーキロータ１８がハブボルト１７により固定されている。このハブ輪１の端部外径に前記車軸軸受２の内輪９，１０を圧入し、そのハブ輪１の突出する端部をナット１９で固定することにより組み付けられている。
【０００６】
【発明が解決しようとする課題】
ところで、前述した従来の車輪軸受装置では、車軸軸受２の外輪６を、外径が異形のナックル３に強タイトで圧入するため、外輪６の軌道面４，５が変形してしまうことがある。このような変形により、軸受のアキシャル振れ等が悪化し、ナックル３への圧入後、ハブ輪１のフランジ１６に取り付けられたブレーキロータ１８に軸方向振れ（又は面振れ）が生じて、自動車の高速走行からのブレーキ時の振動の原因となったり、ブレーキの偏摩耗の原因になったりする。
【０００７】
また、高い予圧を付与して軸受剛性を高めることも考えられるが、ハブ輪１と一対の内輪９，１０間、外輪６とナックル３間といった嵌め合い部分があるため、嵌め合い公差の集積上、予圧のためのすきま減少量のばらつき範囲が大きくならざるを得ず、必ずしも十分な予圧を付与し得る構造ではなかった。
【０００８】
そこで、本発明は前記問題点に鑑みて提案されたもので、その目的とするところは、軸受剛性を向上させることにより、ブレーキロータの軸方向振れを抑制し得る車輪軸受装置を提供することにある。
【０００９】
【課題を解決するための手段】
前記目的を達成するための技術的手段として、本発明は、内周に複列の軌道面２１，２２を一体に設けた外方部材２４と、一端に車輪取付け用フランジ２５、他端に円筒状小径段部２６を設け、その小径段部２６に内輪２８を圧入して前記外方部材２４の軌道面２１，２２に対向する複列の軌道面２９，３０のうち、車輪取付け用フランジ側の軌道面２９を外周に直接形成した内方部材３１と、前記外方部材２４と内方部材３１の両軌道面２１，２２と２９，３０間に介在する複列の転動体３２，３３とを備え、前記内方部材３１の小径段部２６の端部を径方向外方に加締めることにより圧入した内輪２８を内方部材３１に固定したものにおいて、前記外方部材２４及び内方部材３１の軌道面２１，２２及び２９，３０と転動体３２，３３とが接触角を有し、かつ、外方部材２４の複列の軌道面２１，２２のピッチＰ ₀ と溝径、内方部材３１の軌道面２９の肩部からの軸方向寸法Ｐ ₁ と溝径、内輪２８の軌道面３０の小径端面からの軸方向寸法Ｐ ₂ と溝径、及び転動体径をそれぞれ管理して選択組み合わせ、軸受すきまが正の状態で内輪２８の圧入を一旦止めた状態で外方部材の軸方向移動量から測定された軸受すきまの測定値と、圧入を一旦止めた状態から内輪２８を内方部材３１の肩部３７に当接するまで圧入して内方部材３１の小径段部２６の端部を加締めた状態に至るまでの内輪２８の軸方向移動量の測定値との差が負の軸受すきまに設定されていることを特徴とする。
【００１１】
本発明では、▲１▼同一空間内で軸受のスパンを広く採る設計が可能となり、軸受剛性を大きく向上させることが可能となる。▲２▼同一空間内で内部諸元を変更し、転動体個数を増加させて軸受剛性を向上させたり、外方部材の肉厚やフランジの肉厚を最適化して外方部材の変形を抑え、軸受剛性を向上させることが可能となる。▲３▼組み込み後の予圧量のばらつき範囲を狭く抑えることができる。予圧が高い方が軸受剛性は高くなる。本発明の車輪軸受装置では、嵌め合いが少なくなるので、嵌め合い公差によるすきま減少量のばらつき成分がゼロになり、従って公差集積上発生していた低予圧領域がなくなる。
【００１２】
本発明に係る車輪軸受装置では、前記転動体がボールである構造のものが可能である。また、前記外方部材の外周に車体取付け用フランジが一体に形成された構造、前記内方部材が中空に形成された構造、前記内方部材にトルク伝達用の凹凸噛合構造、例えばセレーション、スプライン又はキーのうちから選択されるいずれかを一体に設けた構造とすることが可能である。
【００１３】
【発明の実施の形態】
本発明に係る車輪軸受装置の実施形態を以下に詳述する。
【００１４】
図１に示す実施形態の車輪軸受装置は、内周に複列の軌道面２１，２２を一体に設け、外周に車体取付け用フランジ２３を一体に有する外方部材２４と、一端に車輪取付け用フランジ２５、他端に円筒状小径段部２６を設け、その小径段部２６の外径に内輪２７，２８を圧入して前記外方部材２４の軌道面２１，２２に対向する複列の軌道面２９，３０を形成した内方部材３１と、前記外方部材２４と内方部材３１のそれぞれの軌道面間に介在する複列の転動体３２と、内方部材３１と外方部材２４との間に介在し、複列の転動体３２を各列ごとに円周方向等間隔に支持する保持器３３とを具備する。
【００１５】
内輪２７，２８と外方部材２４の両端には、外部からの異物の侵入や内部に充填したグリースの漏出を防止するためにシール３４を装着している。内方部材３１の車輪取付け用フランジ２５の円周方向等間隔位置に車輪ホイールを固定するためのハブボルト３５が取り付けられている。また、内方部材３１のフランジ２５には、ブレーキロータ３６がハブボルト３５により固定されている。さらに、外方部材２４の車体取付け用フランジ２３には、ナックル（図示せず）を介して車体の懸架装置が取り付けられている。
【００１６】
本発明は、前記実施形態以外にも、図２に示すような構造を有する実施形態も可能である。この実施形態の車輪軸受装置は、前記内方部材３１の軌道面２９，３０のうち、車輪取付け用フランジ側（アウトボード側）の軌道面２９を内方部材３１の外径に直接形成した構造を有する。その他の構造については、図１の実施形態と同様であるため、同一部分には同一参照符号を付して重複説明は省略する。
【００１７】
これらの実施形態では、軸受構造が、外方部材２４の軌道面２１，２２及び内方部材３１の軌道面２９，３０と転動体３２とが接触角を有する複列アンギュラ玉軸受構造であるために軸受負荷容量が大きい。他の軸受構造として、転動体に円すいころを使用した複列円すいころ軸受構造を採用することも可能である。
【００１８】
前記内方部材３１の小径段部２６の端部を径方向外方に加締めることにより、その小径段部２６の外径に圧入された内輪２７，２８を内方部材３１に固定する。この内方部材３１の一端を加締めることにより、内輪２７，２８が内方部材３１の肩部３７との間に挟持されて軸方向で位置決めされ、軸受すきまが負に設定されて転動体３２に定められた予圧が付与された状態で内方部材３１に固定される。
【００１９】
この加締めは、内輪２７，２８の内径に内方部材３１の小径段部２６を挿入し、インナー側に突出した内方部材３１の小径段部２６の端部外径を円筒状のポンチ等で加圧し、径方向外側に塑性変形させることにより行われる。この塑性変形によって形成された加締め部分３８は、図３に示すように内輪２８の内周面よりも外径側に突出し、かつ、円周方向の一部領域で連続した複数、例えば四つの第一領域３９と、隣接する第一領域３９間に形成され、第一領域３９よりも外径側に突出してその肉厚が第一領域３９よりも薄い第二領域４０とで構成される。
【００２０】
この第一領域３９及び第二領域４０は、加圧面の四箇所に半径方向の突出部を設けた押し型を用いることによって一工程で同時成形することができる。この場合、突出部で第二領域４０が、突出部間の平面部分で第一領域３９がそれぞれ成形される。両領域３９，４０を同時に成形する他、両領域３９，４０を別工程で、例えば第一領域３９の成形後に第二領域４０を成形するようにしてもよい。
【００２１】
前記加締め部分３８のうち、主に第一領域３９は、内輪２８との間の隙間を充足して内輪２８のがたつきを防止し、第二領域４０は第一領域３９よりも大きな拘束力で内輪２８の抜けを防止する機能を発揮する。この場合、第一領域３９の変形量は第二領域４０に比べて小さく、その一方で第二領域４０によって内輪２８に対する拘束力が十分に確保されているため、加締め部分３８全体で見れば、少ない変形量でもって十分な拘束力を得られ、加締め時の予肉量の不足が発生することなく、加締め部分３８での耐久性の向上を図ることが可能である。加締めはこれ以外にも、内方部材３１の端部に凹みを形成し、直径方向外方に広げる通常の加締めでもよい。
【００２２】
この実施形態では、前記加締めにより軸受すきまが負に設定されて予圧が付与された構造を具備している。軸受すきまは、軸受加工工程において、外方部材２４の複列の軌道面２１，２２のピッチＰ₀と溝径、内輪２７の軌道面２９の小径端面（又は内方部材３１の軌道面２９の肩部３７）からの軸方向寸法Ｐ₁と溝径、内輪２８の軌道面３０の小径端面からの軸方向寸法Ｐ₂と溝径、及びボール径をそれぞれ管理して選択組み合わせすることにより所望の負の軸受すきまに設定することができる。
【００２３】
負の軸受すきまは、以下の要領で測定することができる。例えば、図２に示す実施形態の場合、内輪２８を内方部材３１に圧入するに際して、軸受すきまが正の状態で内輪２８の圧入を一旦止め、この状態で軸受すきまを例えば外方部材２４の軸方向移動量から測定し、その後、内輪２８を内方部材３１の肩部３７に当接するまで圧入してその圧入を完了し、圧入を一旦止めた状態から圧入を完了した状態に至るまでの内輪２８の軸方向移動量を測定し、その内輪２８の軸方向移動量の測定値と軸受すきまの測定値との差を組み立て完了後の負の軸受すきまとして求めればよい。
【００２４】
本発明の実施形態では、負の軸受すきまで予圧を付与したことにより、同一空間内で軸受のスパン〔Ｓ₀（図４の従来例）＜Ｓ₁（図１の実施形態）＜Ｓ₂（図２の実施形態）〕を広く採る設計が可能となり、軸受剛性を大きく向上させることが可能となる。また、同一空間内で内部諸元を変更し、転動体個数を増加させて軸受剛性を向上させたり、外方部材２４の肉厚やフランジ２３の肉厚を最適化して外方部材２４の変形を抑え、軸受剛性を向上させることが可能となる。さらに、組み込み後の予圧量のばらつき範囲を狭く抑えて高い予圧を維持させることができる。すなわち、図４の従来例に比べて図１の実施形態、さらには図２の実施形態の方が嵌め合いが少なくなるので、嵌め合い公差によるすきま減少量のばらつき成分がゼロになり、従って、公差集積上発生していた低予圧領域がなくなり、軸受剛性も高まる。
【００２５】
図１及び図２に示す実施形態は、自動車の従動輪用としての構造例であるが、本発明はこれに限定されることなく、自動車の駆動輪用としても適用可能である。その場合、内方部材は、その中心部に軸方向に貫通孔が形成された中空形状をなし、その貫通孔の内径面にスプライン又はセレーション等が形成される。その内方部材の貫通孔に等速自在継手の軸部を挿通し、その軸部の外径面に形成されたスプライン又はセレーション等との結合により両者間でトルク伝達が可能となる。また、従動輪用においても、内方部材を中空構造とし、放熱効果を向上して、軸受の昇温の抑制や軽量化を図ることもできる。
【００２６】
【発明の効果】
本発明によれば、内周に複列の軌道面を一体に設けた外方部材と、一端に車輪取付け用フランジ、他端に円筒状小径段部を設け、その小径段部に内輪を圧入して前記外方部材の軌道面に対向する複列の軌道面を形成した内方部材と、前記外方部材と内方部材の両軌道面間に介在する複列の転動体とを備えた構造、或いは、前記内方部材の軌道面のうち、車輪取付け用フランジ側の軌道面を内方部材の外周に直接形成した構造において、前記外方部材及び内方部材の軌道面と転動体とが接触角を有し、かつ、軸受すきまが負に設定されていることから、軸受剛性の向上が容易に図れ、内方部材の車輪取付け用フランジにブレーキロータを装着した場合、そのブレーキロータの軸方向振れを抑制することができる。また、前記軸受構造において、前記内方部材の小径段部の端部を径方向外方に加締めることにより圧入した内輪を内方部材に固定したことにより、装置全体の軽量、コンパクト化を実現することが容易になる。
【００２７】
また、内方部材が中空に形成された構造、前記内方部材にトルク伝達用の凹凸噛合構造、例えばセレーション、スプライン又はキーのうちから選択されるいずれかを一体に設けた構造とすれば、本発明の車輪軸受装置を従動車輪用だけでなく、駆動車輪用としても兼用することができる。駆動輪側において、等速自在継手の組立時に、ナットの締付けトルクの管理による軸受すきまの調整が不要となる。
【図面の簡単な説明】
【図１】本発明に係る車輪軸受装置の実施形態を示す断面図
【図２】本発明の他の実施形態を示す断面図
【図３】図１又は図２の内方部材の加締め部分を示す側面図
【図４】車輪軸受装置の従来例を示す断面図
【符号の説明】
２１，２２軌道面
２３車体取付け用フランジ
２４外方部材
２５車輪取付け用フランジ
２６小径段部
２７，２８内輪
２９，３０軌道面
３１内方部材
３２転動体
３８加締め部分[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wheel bearing device, and more particularly to a wheel bearing device that is used in an automobile and can improve bearing rigidity.
[0002]
[Prior art]
FIG. 4 shows an example of a wheel bearing device used in an automobile, and shows a structure when used for a driven wheel. This bearing device has a structure in which a hub wheel 1 is rotatably supported by an axle bearing 2, a wheel wheel is fixed to the hub wheel 1, and the axle bearing 2 is supported by a vehicle body suspension device via a knuckle 3. .
[0003]
The axle bearing 2 is a double-row rolling bearing, and includes an outer ring 6 in which double-row raceway surfaces 4 and 5 are formed on the inner diameter surface, and inner rings 9 and 10 in which raceway surfaces 7 and 8 are formed on the outer diameter surface. The double-row rolling elements 11 interposed between the outer ring 6 and the inner rings 9 and 10 and the cage 12 that supports the rolling elements 11 in each row at equal intervals in the circumferential direction.
[0004]
The outer ring 6 is press-fitted into the knuckle 3 and fixed with a retaining ring 13. Seals 14 and 15 are provided to prevent intrusion of foreign matter from the outside and leakage of grease filled inside the axle bearing 2. In the illustrated example, a double-row angular ball bearing is used as the axle bearing 2.
[0005]
The hub wheel 1 includes a flange 16, and hub bolts 17 for fixing the wheel wheels are attached to the flange 16 at equal circumferential positions. A brake rotor 18 is fixed to the flange 16 of the hub wheel 1 by a hub bolt 17. The hub ring 1 is assembled by press-fitting the inner rings 9 and 10 of the axle bearing 2 into the outer diameter of the end of the hub wheel 1 and fixing the protruding end of the hub wheel 1 with a nut 19.
[0006]
[Problems to be solved by the invention]
By the way, in the above-described conventional wheel bearing device, the outer ring 6 of the axle bearing 2 is pressed tightly into the knuckle 3 having a different outer diameter, so that the raceway surfaces 4 and 5 of the outer ring 6 may be deformed. . Such deformation deteriorates axial runout of the bearing, and after press-fitting into the knuckle 3, axial runout (or runout) occurs in the brake rotor 18 attached to the flange 16 of the hub wheel 1. This may cause vibration during braking from high speed running or cause uneven wear of the brake.
[0007]
It is also conceivable to increase the bearing rigidity by applying a high preload. However, since there are fitting parts such as between the hub wheel 1 and the pair of inner rings 9 and 10 and between the outer ring 6 and the knuckle 3, the fitting tolerances are accumulated. However, the variation range of the clearance reduction amount for the preload has to be large, and the structure is not necessarily capable of providing a sufficient preload.
[0008]
Therefore, the present invention has been proposed in view of the above problems, and an object of the present invention is to provide a wheel bearing device that can suppress axial deflection of the brake rotor by improving bearing rigidity. is there.
[0009]
[Means for Solving the Problems]
As technical means for achieving the above object, the present invention includes an outer member 24 integrally provided with double-row track surfaces 21 and 22 on the inner periphery, a wheel mounting flange 25 at one end, and a cylinder at the other end. Of the double row raceway surfaces 29 and 30 facing the raceway surfaces 21 and 22 of the outer member 24 by press-fitting an inner ring 28 into the small diameter step portion 26. An inner member 31 formed directly on the outer periphery of the raceway surface 29, and double row rolling elements 32, 33 interposed between the raceway surfaces 21, 22 and 29, 30 of the outer member 24 and the inner member 31, And fixing the inner ring 28 press-fitted by crimping the end of the small-diameter step portion 26 of the inner member 31 radially outward to the inner member 31, the outer member 24 and the inner member 31 raceway surfaces 21, 22 and 29, 30 and rolling elements 32, 33; It has a contact angle, and the pitch P ₀ and the groove diameter of the double row raceway surfaces 21, 22 of the outer member 24, the axial dimension P ₁ from the shoulder of the raceway surface 29 of the inner member 31 groove diameter The axial dimension P ₂ from the small diameter end face of the raceway surface 30 of the inner ring 28, the groove diameter, and the rolling element diameter are respectively managed and selected and combined, and the press-fit of the inner ring 28 is temporarily stopped while the bearing clearance is positive. The measured value of the bearing clearance measured from the axial movement amount of the outer member and the small diameter of the inner member 31 by press-fitting the inner ring 28 from the state where the press-fitting is temporarily stopped until the inner ring 28 comes into contact with the shoulder portion 37 of the inner member 31. A difference from the measured value of the axial movement amount of the inner ring 28 until the end portion of the step portion 26 is crimped is set to a negative bearing clearance.
[0011]
In the present invention, (1) it is possible to design the bearing span widely in the same space, and the bearing rigidity can be greatly improved. (2) Change the internal specifications within the same space, increase the number of rolling elements to improve bearing rigidity, and optimize the outer member thickness and flange thickness to suppress deformation of the outer member. The bearing rigidity can be improved. (3) The range of variation in the preload amount after incorporation can be kept narrow. The higher the preload, the higher the bearing rigidity. In the wheel bearing device of the present invention, since the fitting is reduced, the variation component of the clearance reduction amount due to the fitting tolerance becomes zero, and accordingly, the low preload region generated due to the tolerance accumulation is eliminated.
[0012]
In the wheel bearing device according to the present invention, a structure in which the rolling element is a ball is possible. Also, a structure in which a body mounting flange is integrally formed on the outer periphery of the outer member, a structure in which the inner member is formed in a hollow shape, and a concave-convex meshing structure for torque transmission to the inner member, such as serrations and splines Alternatively, a structure in which any one selected from the keys is integrally provided can be used.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a wheel bearing device according to the present invention will be described in detail below.
[0014]
The wheel bearing device of the embodiment shown in FIG. 1 has an outer member 24 integrally provided with double-row raceway surfaces 21 and 22 on the inner periphery and a body mounting flange 23 on the outer periphery, and a wheel attachment on one end. A cylindrical small diameter step portion 26 is provided at the flange 25 and the other end, and inner rings 27 and 28 are press-fitted into the outer diameter of the small diameter step portion 26 so as to face the raceway surfaces 21 and 22 of the outer member 24. An inner member 31 having surfaces 29 and 30; a double row rolling element 32 interposed between the raceway surfaces of the outer member 24 and the inner member 31; the inner member 31 and the outer member 24; And a retainer 33 that supports the double-row rolling elements 32 at equal intervals in the circumferential direction.
[0015]
Seals 34 are attached to both ends of the inner rings 27, 28 and the outer member 24 in order to prevent entry of foreign matter from the outside and leakage of grease filled in the inside. Hub bolts 35 for fixing the wheel wheels are attached to the circumferentially equidistant positions in the circumferential direction of the wheel mounting flange 25 of the inner member 31. A brake rotor 36 is fixed to the flange 25 of the inner member 31 with a hub bolt 35. Furthermore, a vehicle body suspension device is attached to the vehicle body attachment flange 23 of the outer member 24 via a knuckle (not shown).
[0016]
In addition to the above-described embodiment, the present invention may have an embodiment having a structure as shown in FIG. The wheel bearing device according to this embodiment has a structure in which, of the raceway surfaces 29 and 30 of the inner member 31, the raceway surface 29 on the wheel mounting flange side (outboard side) is directly formed on the outer diameter of the inner member 31. Have Since the other structure is the same as that of the embodiment of FIG. 1, the same reference numerals are given to the same parts, and the duplicate description is omitted.
[0017]
In these embodiments, the bearing structure is a double-row angular contact ball bearing structure in which the raceway surfaces 21 and 22 of the outer member 24 and the raceway surfaces 29 and 30 of the inner member 31 and the rolling elements 32 have contact angles. The bearing load capacity is large. As another bearing structure, it is also possible to adopt a double row tapered roller bearing structure in which tapered rollers are used as rolling elements.
[0018]
The inner rings 27 and 28 press-fitted into the outer diameter of the small-diameter step portion 26 are fixed to the inner member 31 by crimping the end of the small-diameter step portion 26 of the inner member 31 radially outward. By crimping one end of the inner member 31, the inner rings 27, 28 are sandwiched between the inner member 31 and the shoulder portion 37 and positioned in the axial direction, the bearing clearance is set negative, and the rolling element 32. And fixed to the inner member 31 in a state where the preload determined in (1) is applied.
[0019]
This caulking is performed by inserting the small-diameter step portion 26 of the inner member 31 into the inner diameter of the inner rings 27 and 28, and setting the outer diameter of the end portion of the small-diameter step portion 26 of the inner member 31 protruding to the inner side to a cylindrical punch or the like. By applying pressure and plastically deforming radially outward. As shown in FIG. 3, the caulking portion 38 formed by this plastic deformation protrudes to the outer diameter side from the inner peripheral surface of the inner ring 28 and is continuous in a partial region in the circumferential direction, for example, four A first region 39 and a second region 40 that is formed between adjacent first regions 39, protrudes to the outer diameter side from the first region 39, and is thinner than the first region 39.
[0020]
The first region 39 and the second region 40 can be simultaneously molded in one step by using a pressing die provided with radial protrusions at four locations on the pressing surface. In this case, the 2nd area | region 40 is shape | molded by the protrusion part, and the 1st area | region 39 is shape | molded by the plane part between protrusion parts, respectively. In addition to forming both regions 39 and 40 simultaneously, both regions 39 and 40 may be formed in separate steps, for example, after forming the first region 39, the second region 40 may be formed.
[0021]
Of the caulking portion 38, the first area 39 mainly satisfies the gap between the inner ring 28 and prevents the inner ring 28 from rattling, and the second area 40 is more restrained than the first area 39. The function of preventing the inner ring 28 from coming off with force is exhibited. In this case, the deformation amount of the first region 39 is smaller than that of the second region 40, and on the other hand, the second region 40 sufficiently secures the restraining force against the inner ring 28. It is possible to obtain a sufficient restraining force with a small amount of deformation, and to improve the durability at the caulking portion 38 without causing a shortage of the pre-mesh amount at the time of caulking. In addition to this, the normal caulking may be performed by forming a dent at the end of the inner member 31 and spreading it outward in the diameter direction.
[0022]
In this embodiment, the bearing clearance is set to be negative by the caulking, and a preload is applied. In the bearing machining process, the bearing clearance is determined by the pitch P ₀ and groove diameter of the double-row raceway surfaces 21 and 22 of the outer member 24, the small-diameter end face of the raceway surface 29 of the inner ring 27 (or the raceway surface 29 of the inner member 31). The axial dimension P ₁ and the groove diameter from the shoulder 37), the axial dimension P ₂ from the small-diameter end face of the raceway surface 30 of the inner ring 28, the groove diameter, and the ball diameter are respectively managed and selectively combined. Negative bearing clearance can be set.
[0023]
Negative bearing clearance can be measured as follows. For example, in the embodiment shown in FIG. 2, when the inner ring 28 is press-fitted into the inner member 31, the press-fitting of the inner ring 28 is temporarily stopped in a state where the bearing clearance is positive. Measured from the amount of movement in the axial direction, and then press-fit until the inner ring 28 comes into contact with the shoulder portion 37 of the inner member 31 to complete the press-fitting. The axial movement amount of the inner ring 28 is measured, and the difference between the measured value of the axial movement amount of the inner ring 28 and the measured value of the bearing clearance may be obtained as the negative bearing clearance after assembly is completed.
[0024]
In the embodiment of the present invention, since the preload is applied up to the negative bearing clearance, the bearing span [S ₀ (conventional example of FIG. 4) <S ₁ (embodiment of FIG. 1) <S ₂ ( The embodiment of FIG. 2)] can be widely adopted, and the bearing rigidity can be greatly improved. Further, by changing the internal specifications in the same space and increasing the number of rolling elements to improve the bearing rigidity, the thickness of the outer member 24 and the thickness of the flange 23 are optimized, and the outer member 24 is deformed. As a result, the bearing rigidity can be improved. Furthermore, a high preload can be maintained by narrowing the variation range of the preload amount after incorporation. That is, since the fitting of the embodiment of FIG. 1 and the embodiment of FIG. 2 is less than the conventional example of FIG. 4, the variation component of the clearance reduction amount due to the fitting tolerance becomes zero. The low preload region that occurs due to tolerance accumulation is eliminated, and the bearing rigidity is increased.
[0025]
The embodiment shown in FIGS. 1 and 2 is an example of a structure for a driven wheel of an automobile, but the present invention is not limited to this and can also be applied to a driving wheel of an automobile. In that case, the inner member has a hollow shape in which a through hole is formed in the axial direction at the center thereof, and a spline or a serration is formed on the inner diameter surface of the through hole. The shaft portion of the constant velocity universal joint is inserted into the through-hole of the inner member, and torque can be transmitted between the two by coupling with a spline or serration formed on the outer diameter surface of the shaft portion. Also for the driven wheel, the inner member can have a hollow structure to improve the heat dissipation effect, thereby suppressing the temperature rise of the bearing and reducing the weight.
[0026]
【The invention's effect】
According to the present invention, an outer member integrally provided with a double row raceway surface on the inner periphery, a wheel mounting flange at one end, a cylindrical small diameter stepped portion at the other end, and an inner ring pressed into the small diameter stepped portion. An inner member having a double row raceway surface facing the raceway surface of the outer member, and a double row rolling element interposed between both raceway surfaces of the outer member and the inner member. In the structure or the structure in which the raceway surface on the wheel mounting flange side is directly formed on the outer periphery of the inner member among the raceway surfaces of the inner member, the raceway surfaces of the outer member and the inner member, and rolling elements Since the bearing has a contact angle and the bearing clearance is set to a negative value, the bearing rigidity can be easily improved. When the brake rotor is mounted on the wheel mounting flange of the inner member, the brake rotor Axial runout can be suppressed. In the bearing structure, the inner ring that has been press-fitted by crimping the end of the small-diameter stepped portion of the inner member radially outwards is fixed to the inner member, thereby reducing the overall weight and size of the device. Easy to do.
[0027]
Further, if the inner member is formed in a hollow structure, the inner member has a concave-convex meshing structure for torque transmission, for example, any one selected from serrations, splines, or keys. The wheel bearing device of the present invention can be used not only for a driven wheel but also for a driving wheel. On the drive wheel side, adjustment of the bearing clearance by managing the tightening torque of the nut becomes unnecessary when assembling the constant velocity universal joint.
[Brief description of the drawings]
1 is a cross-sectional view showing an embodiment of a wheel bearing device according to the present invention. FIG. 2 is a cross-sectional view showing another embodiment of the present invention. FIG. 3 is a caulking portion of the inner member of FIG. FIG. 4 is a sectional view showing a conventional example of a wheel bearing device.
21, 22 Track surface 23 Car body mounting flange 24 Outer member 25 Wheel mounting flange 26 Small-diameter stepped portions 27, 28 Inner rings 29, 30 Track surface 31 Inner member 32 Rolling element 38 Clamping portion

Claims

An outer member 24 integrally provided with double-row raceway surfaces 21 and 22 on the inner periphery, a wheel mounting flange 25 at one end, and a cylindrical small diameter step portion 26 at the other end, an inner ring 28 at the small diameter step portion 26. The inner member 31 formed by directly forming the raceway surface 29 on the wheel mounting flange side among the double row raceway surfaces 29 and 30 facing the raceway surfaces 21 and 22 of the outer member 24 by press-fitting A plurality of rolling elements 32 and 33 interposed between the raceway surfaces 21 and 22 and 29 and 30 of the outer member 24 and the inner member 31, respectively, and an end portion of the small-diameter step portion 26 of the inner member 31; In which the inner ring 28 press-fitted by crimping radially outward is fixed to the inner member 31, the raceway surfaces 21, 22 and 29, 30 of the outer member 24 and the inner member 31 and the rolling elements 32, 33 has a contact angle, and the double-row raceway surface 21 of the outer member 24 22 of pitch P ₀ and groove diameter, axial dimension P ₁ and the groove diameter of the shoulder of the raceway surface 29 of the inner member 31, the axial dimension P ₂ from the small-diameter end face of the raceway surface 30 of the inner ring 28 groove diameter , And the rolling element diameters are selected and combined, and the bearing clearance measurement value measured from the amount of axial movement of the outer member with the bearing clearance being positive and the inner ring 28 once stopped, and the press fit The axial direction of the inner ring 28 until the inner ring 28 is press-fitted until the inner ring 28 comes into contact with the shoulder 37 of the inner member 31 and the end of the small diameter step portion 26 of the inner member 31 is crimped. A wheel bearing device, characterized in that a difference from a measured value of a moving amount is set to a negative bearing clearance.

The wheel bearing device according to claim 1 , wherein the rolling elements (32, 33) are balls.

The wheel bearing device according to claim 1 or 2 , wherein a body mounting flange (23) is integrally formed on an outer periphery of the outer member (24).

The wheel bearing device according to any one of claims 1 to 3 , wherein the inner member (31) is hollow.

The wheel bearing device according to claim 4 , wherein the inner member 31 is integrally provided with a concave-convex meshing structure for torque transmission.

6. The wheel bearing device according to claim 5 , wherein the concave-convex engagement structure is any one selected from serrations, splines, and keys.