JP4207244B2

JP4207244B2 - Rolling bearing unit with rotational speed detection device and method of processing outer ring for rolling bearing unit with rotational speed detection device

Info

Publication number: JP4207244B2
Application number: JP12772598A
Authority: JP
Inventors: 雄二中村; 裕也宮崎; 修一石川
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 1998-03-09
Filing date: 1998-05-11
Publication date: 2009-01-14
Anticipated expiration: 2018-05-11
Also published as: JPH11325058A

Description

【０００１】
【発明の属する技術分野】
この発明は、自動車の車輪を懸架装置に対して回転自在に支持すると共に、この車輪の回転速度を検出する為に利用する回転速度検出装置付転がり軸受ユニット、並びにこの回転速度検出装置付転がり軸受ユニットを構成する外輪の改良に関する。
【０００２】
【従来の技術】
自動車の車輪を懸架装置に対して回転自在に支持するのに、転がり軸受ユニットを使用する。又、アンチロックブレーキシステム（ＡＢＳ）やトラクションコントロールシステム（ＴＣＳ）を制御する為には、上記車輪の回転速度を検出する必要がある。この為、上記転がり軸受ユニットに回転速度検出装置を組み込んだ、回転速度検出装置付転がり軸受ユニットにより、上記車輪を懸架装置に対して回転自在に支持すると共に、この車輪の回転速度を検出する事が、近年広く行なわれる様になっている。
【０００３】
この様な回転速度検出装置付転がり軸受ユニットは、外輪の内径側にハブを、複数の転動体を介して回転自在に支持している。これと共に、上記ハブの一部に固定した、円周方向に亙って特性を交互に且つ等間隔に変化させたエンコーダの回転速度を、上記外輪の一部に支持したセンサにより検出自在としている。又、このセンサを、上記外輪の軸方向中間部に、この外輪の直径方向に亙り形成した取付孔内に支持した状態で、このセンサの検出部を上記エンコーダの大径円筒部の外周面に対向させる事も、例えば特開昭６３−５９７６９号公報、特開平６−１０９０２７号公報、同８−２７０６５９号公報等、多くの刊行物に記載されている様に、従来から広く知られている。
【０００４】
上述の様な回転速度検出装置付転がり軸受ユニットの使用時には、上記外輪を懸架装置に支持すると共に、上記ハブの一端部で上記外輪から外れた部分に車輪を固定し、この車輪を上記懸架装置に対して回転自在に支持する。車輪の回転に伴って上記エンコーダが回転すると、検出部をこのエンコーダに対向させたセンサの出力が変化する。このセンサの出力が変化する周波数は、上記車輪の回転速度に比例する。従って、このセンサの出力信号を上記車輪の回転速度を求める制御器に送れば、ＡＢＳやＴＣＳを適切に制御できる。
【０００５】
【発明が解決しようとする課題】
上述の様な各公報に記載された回転速度検出装置付転がり軸受ユニットの場合、外輪の耐久性確保と取付孔の加工容易性との両立を考慮していなかった。即ち、外輪の内周面に形成した複列の外輪軌道の表面及びこの表面近傍部分には、これら各外輪軌道の転がり疲れ寿命確保を目的として、硬度が例えばHv５００以上である焼き入れ硬化層を形成する必要がある。又、上記外輪の一部内周面部分で複列の外輪軌道の間部分にも焼き入れ硬化層を形成し、この間部分を塑性変形しにくくする事も、例えば実用新案登録第２５２９５９７号公報等にも記載されている様に、従来から知られている。この様に、上記間部分を塑性変形しにくくすると、車輪が縁石にぶつかる等により、上記外輪に衝撃荷重が加わった場合でも、この外輪が塑性変形する事を防止して、この外輪を含む回転速度検出装置付転がり軸受ユニットの耐久性向上を図れる。尚、この様な場合でも、上記外輪の外周寄り部分には、焼き入れ硬化されていない生の部分を残して、上記外輪の靱性を確保し、この外輪に上記衝撃荷重に基づいて亀裂等の損傷が生じる事を防止する。
【０００６】
ところが、上述の様に、外輪の一部内周面で複列の外輪軌道の間部分にも焼き入れ硬化層を形成した場合には、センサを支持固定する為に外輪に形成する取付孔の加工が難しくなる。
又、上記外輪の靱性を確保し、自動車の走行時に加わる可能性のある衝撃荷重に拘らず、この外輪に亀裂等の損傷が発生する事を防止すべく、この外輪の一部で上記間部分の外径寄り部分に、焼き入れ硬化されていない生の部分を残す為には、上記外輪の内周面に焼き入れ硬化層を、この外輪の外周面を冷媒により冷却しつつ形成する必要がある。この様な場合に、この外輪の内周面に冷媒が入り込み、焼き入れ硬化層にむらが生じる事を防止する必要があるが、従来は、この様な事を考慮する発明は知られていなかった。
本発明の回転速度検出装置付転がり軸受ユニットと回転速度検出装置付転がり軸受ユニット用外輪の加工方法は、この様な事情に鑑みて、焼き入れ硬化層により変形防止を図った外輪にも、センサを支持固定する為の取付孔を形成可能にすると共に、必要に応じて焼き入れ硬化層にむらが生じるのを防止すべく発明したものである。
【０００７】
【課題を解決するための手段】
本発明の対象となる回転速度検出装置付転がり軸受ユニットは、従来から知られている回転速度検出装置付転がり軸受ユニットと同様に、外周面に複列の内輪軌道を有し、使用時に車輪と共に回転するハブと、内周面で上記複列の内輪軌道と対向する位置に複列の外輪軌道を有し、使用時に懸架装置に支持されて回転しない外輪と、上記各内輪軌道と上記各外輪軌道との間にそれぞれ複数個ずつ転動自在に設けた転動体と、上記ハブの中間部外周面で上記複列の内輪軌道の間部分に外嵌固定した、円周方向に亙って特性を交互に且つ等間隔に変化させたエンコーダと、検出部を有し、この検出部を上記エンコーダに対向させた状態で上記外輪の軸方向中間部に設けた取付孔内に支持され、上記エンコーダの特性の変化に対応して出力信号を変化させるセンサとを備える。そして、上記外輪の内周面で上記各外輪軌道部分及びこれら両外輪軌道の間部分に焼き入れ硬化層を形成している。
【０００８】
特に、本発明の回転速度検出装置付転がり軸受ユニットのうち、請求項１に記載した回転速度検出装置付転がり軸受ユニットに於いては、上記焼き入れ硬化層は、上記取付孔を上記外輪の外周面側から直径方向に関して途中まで形成した状態で、この外輪を外周面側から冷媒により冷却しつつこの外輪の内周面を加熱して形成したものであり、上記取付孔は、上記焼き入れ硬化層を形成した後、上記外輪の内周面側にまで貫通させたものである。
【０００９】
そして、請求項２に記載した回転速度検出装置付転がり軸受ユニットを構成する外輪の加工方法は、取付孔を外輪の外周面側から直径方向に関して途中まで形成してから、上記外輪を外周面側から冷媒により冷却しつつこの外輪を内周面側から加熱して焼き入れ硬化層を形成した後、上記取付孔をこの外輪の内周面側にまで貫通させる。
【００１０】
又、請求項３に記載した回転速度検出装置付転がり軸受ユニットに於いては、上記焼き入れ硬化層は、上記取付孔を形成した後、上記外輪を回転させながらこの外輪の外周面部分を、下方から上方に向けて吹き上げる冷媒により冷却しつつ、この外輪の内周面を加熱して形成したものである。
【００１１】
そして、請求項４に記載した回転速度検出装置付転がり軸受ユニットを構成する外輪の加工方法は、外輪の軸方向中間部で複列の外輪軌道の間部分に取付孔を形成した後、この外輪を回転させながら、この外輪の外周面部分を下方から上方に向けて吹き上げる冷媒により冷却しつつ、この外輪の内周面を加熱して、焼き入れ硬化層を形成する。
【００１２】
更に、請求項５に記載した回転速度検出装置付転がり軸受ユニットに於いては、上記焼き入れ硬化層は、上記取付孔を形成した後、この外輪の外周面部分を気体冷媒により冷却しつつ、この外輪の内周面を加熱して形成したものである。
そして、請求項６に記載した回転速度検出装置付転がり軸受ユニットを構成する外輪の加工方法は、外輪の軸方向中間部で複列の外輪軌道の間部分に取付孔を形成した後、この外輪の外周面部分を気体冷媒により冷却しつつ、この外輪の内周面を加熱して、焼き入れ硬化層を形成する。
【００１３】
【作用】
上述の様に造る外輪を含んで構成する本発明の回転速度検出装置付転がり軸受ユニットにより、車輪を懸架装置に対して回転自在に支持すると共に、この車輪の回転速度を検出する際の作用は、従来から一般的に知られている回転速度検出装置付転がり軸受ユニットの場合と同様である。
【００１４】
特に、本発明の回転速度検出装置付転がり軸受ユニットと回転速度検出装置付転がり軸受ユニット用外輪の加工方法によれば、焼き入れ硬化層により変形防止を図った外輪にも、センサを支持固定する為の取付孔を形成できる。この為、衝撃により変形しにくい外輪を備え、しかもこの外輪の軸方向中間部に形成した取付孔にセンサを支持固定した回転速度検出装置付転がり軸受ユニットを実現できる。
【００１５】
【発明の実施の形態】
図１〜２は、本発明に関連する参考例の第１例を示している。本参考例の回転速度検出装置付転がり軸受ユニットを構成する転がり軸受ユニットは、ハブ本体１と内輪２とを組み合わせて成るハブ３と、外輪４と、複数個の転動体５、５とを備える。このうちのハブ本体１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、図１〜２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、図１〜２の右側となる。）には、車輪を支持する為のフランジ６を設けている。又、上記ハブ本体１の中間部外周面には内輪軌道７を形成している。尚、この内輪軌道７は、上記ハブ本体１の中間部外周面に直接形成する他、このハブ本体１の中間部外周面に外嵌した別体の内輪の外周面に形成する場合もある。
【００１６】
又、上記ハブ本体１の内端部には、このハブ本体１の外周面から直径方向内方に凹入する段部８を、全周に亙りこのハブ本体１と同心に設けている。そして、この段部８に、外周面に別の内輪軌道７を形成した上記内輪２を、締り嵌めにより外嵌固定している。又、この様に外嵌固定した状態で上記内輪２の内端部は、上記ハブ本体１の内端面から軸方向内方に突出する。この内輪２の内端面は、車両への組み付け状態で、図示しない等速ジョイントの段差面に当接する。又、やはり車両への組み付け状態で、上記ハブ本体１の中心部に設けたスプライン孔９には、上記等速ジョイントに付属したスプライン軸を挿通する。そして、このスプライン軸の先端部で上記ハブ本体１の外端面よりも外方に突出した部分に設けた雄ねじ部に、やはり図示しないナットを螺合し、更に緊締する。このナットの緊締に基づいて、等速ジョイントの段差面が上記内輪２の内端面を強く押圧し、この内輪２が上記段部８から抜け出るのを防止する。又、上記段部８よりも大径に形成した上記ハブ本体１の中間部のうち、上記段部８側の端部には、このハブ本体１の中間部よりも少しだけ小径の嵌着部１０を設けている。この嵌着部１０の外径は、後述するエンコーダ１１の自由状態での内径よりも僅かに大きくして、このエンコーダ１１を締り嵌めにより外嵌固定自在としている。又、このエンコーダ１１の外径は、上記嵌着部１０に外嵌固定した状態で、ハブ本体１の中間部でこの嵌着部１０よりも外寄り部分の外径以下としている。
【００１７】
又、上記外輪４の内周面には、それぞれ上記各内輪軌道７、７と対向する、複列の外輪軌道１２、１２を形成している。そして、これら各内輪軌道７、７と各外輪軌道１２、１２との間にそれぞれ複数個ずつの転動体５、５を、それぞれ保持器１３、１３により保持した状態で転動自在に設ける事により、上記外輪４の内側に上記ハブ本体１及び内輪２を回転自在に支持している。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。又、上記外輪４の内端寄り部分の外周面には、この外輪４を懸架装置に取り付ける為の外向フランジ状の取付部１４を設けている。又、上記外輪４の両端開口部と上記ハブ本体１の中間部外周面及び上記内輪２の内端部外周面との間の隙間は、それぞれシールリング１５、１５により塞いでいる。
【００１８】
又、上記ハブ本体１の中間部外周面の一部で上記嵌着部１０に、エンコーダ１１を、このハブ本体１と同心に外嵌固定している。このエンコーダ１１は、鋼板等の磁性金属板により、全体を円筒状に形成したもので、上記嵌着部１０に締り嵌めで外嵌固定する事により、上記複列に設けた転動体５、５の列の間部分に配置している。又、このエンコーダ１１の軸方向中間部には複数の透孔１６、１６を、円周方向に亙って等間隔に形成する事により、上記エンコーダ１１の外周面の磁気特性を、円周方向に亙って交互に且つ等間隔に変化させている。
【００１９】
一方、上記外輪４の軸方向中間部で上記エンコーダ１１の直径方向外方位置には、取付孔１７を、上記外輪４の内周面と外周面とを互いに連通させる状態で形成している。そして、この取付孔１７内に、検出素子を合成樹脂中に包埋しているセンサ１８を挿入固定し、このセンサ１８の先端面（図１の下端面）に設けた検出部を、上記エンコーダ１１の外周面に、微小隙間を介して対向させている。この様に取付孔１７にセンサ１８を挿入固定した状態で、このセンサ１８は、上記エンコーダ１１の回転速度を検出自在である。
【００２０】
又、上記外輪４の外周面で上記取付孔１７の外端開口の周囲部分には、この取付孔１７の中心軸に対して直交する方向に存在する、平坦な取付面１９を形成している。そして、この取付面１９と上記取付孔１７の内周面との連続部に、円錐凹面状の面取り部２０と受面２１とを、上記取付面１９の側から順番に形成している。一方、上記センサ１８の基端部（図１の上端部）には取付部２２を固設し、この取付部２２の端部に挿通した図示しないねじにより、この取付部２２を上記外輪４に結合固定している。この状態で、上記センサ１８の基端部に外嵌したＯリング２３を、この基端部の外周面と上記受面２１の内周面との間で弾性的に圧縮する事により上記センサ１８を装着した部分を密封し、上記取付孔１７を通じて、雨水等の異物が上記外輪４内に侵入する事を防止している。
【００２１】
更に、上記外輪４の内周面で前記各外輪軌道１２、１２部分及びこれら両外輪軌道１２、１２の間部分に、例えば硬度がHv５００以上である焼き入れ硬化層２４を形成している。この焼き入れ硬化層２４の一部で上記各外輪軌道１２、１２に存在する部分は、前記各転動体５、５の転動面から繰り返し加えられる荷重に拘らず、上記各外輪軌道１２、１２部分の転がり疲れ寿命を確保する。これに対して、上記焼き入れ硬化層２４の残部で両外輪軌道１２、１２の間部分に存在する中間部分は、この間部分を塑性変形しにくくする事により、車輪が縁石に乗り上げる等により上記各転動体５、５から加わる衝撃荷重に拘らず、上記外輪４のうちで上記間部分が塑性変形する事を防止する。尚、上記焼き入れ硬化層２４は、外輪４の外周面部分を、冷却水、冷却油等の冷媒により冷却しつつ、この外輪４を内周面側から加熱して形成する（後述する本発明の実施の形態の第１例以下も同様）。この様に、外輪４の外周面部分を冷却しつつ、上記焼き入れ硬化層２４を形成する理由は、この焼き入れ硬化層２４の外径が過度に大きくなる事を防止して、上記外輪４の外周面側までもが硬くなる事を防止し、この外輪４の靱性を確保して、自動車の運行時に加わる可能性のある衝撃荷重に拘らず、この外輪４に割れ等の損傷が発生する事を防止する為である。合わせて、上記取付孔１７の加工を行ないにくい上記焼き入れ硬化層２４の厚さを薄くして、この取付孔１７の加工の容易化を図っている。
【００２２】
内周面に上述の様な焼き入れ硬化層２４を形成した外輪４の軸方向中間部で、上記両外輪軌道１２、１２の間部分に上記取付孔１７を、上記焼き入れ硬化層２４を形成した後、超硬ドリル又はセラミックチップを備えたドリルにより形成している。上記間部分のうち、内周面寄りに存在する上記焼き入れ硬化層２４部分は、例えば硬度がHv５００以上と硬いが、超硬ドリル又はセラミックチップを備えたドリルによれば、十分に上記取付孔１７を加工できる。従って、上記焼き入れ硬化層２４により変形防止を図った外輪４にも、前記センサ１８を支持固定する為の取付孔１７を形成できる。尚、上記取付孔１７を上記超硬ドリル又はセラミックチップを備えたドリルにより切削加工する際には、少なくとも切削部に切削油を注いで、切削部の冷却及び潤滑を行なう。この際に使用する潤滑油としては、非水溶性のものが好ましい。又、焼き入れ硬化層２４部分に孔あけ加工をする際に発生する発熱は大きい為、上述の様に切削油を注ぐだけでなく、加工速度（上記ドリルの回転速度）を、鋼の生の部分に孔あけ加工をする場合に比べて遅くする事が好ましい。即ち、上記ドリルによる取付孔１７の切削速度は、この取付孔１７の内径（＝ドリルの外径）が１１〜１３mm程度とした場合で、上記ドリルの外周面の速度で表して、２０m/min 以下、更に好ましくは１０m/min 以下にする。尚、焼き入れ硬化層でない、生の部分に上記取付孔１７をあける場合の切削速度は、３５〜４１m/min 程度である。
【００２３】
上述の様な本参考例の回転速度検出装置付転がり軸受ユニットの場合、ハブ本体１の外端部に設けたフランジ６に固定した車輪を、外輪４を支持した懸架装置に対し、回転自在に支持できる。又、車輪の回転に伴って上記ハブ本体１に外嵌固定したエンコーダ１１が回転すると、上記センサ１８の先端面に設けた検出部の近傍を、上記エンコーダ１１の軸方向中間部に設けた透孔１６、１６と円周方向に隣り合う透孔１６、１６同士の間に存在する柱部とが交互に通過する。この結果、上記センサ１８内を流れる磁束の量（密度）が変化し、このセンサ１８の出力が変化する。この様にしてセンサ１８の出力が変化する周波数は、車輪の回転速度に比例する。従って、センサ１８の出力を図示しない制御器に送れば、ＡＢＳやＴＣＳを適切に制御できる。
【００２４】
次に、図３〜５は、請求項１〜２に対応する、本発明の実施の形態の第１例を示している。本例の場合には、回転速度検出装置付転がり軸受ユニットを構成する外輪４の内周面の外輪軌道１２、１２及びこれら両外輪軌道１２、１２の間部分の焼き入れ硬化層２４は、この間部分に取付孔１７の元となる、有底の凹孔２７を、この間部分の外周面側から形成した状態で形成したものである。又、上記取付孔１７は、上記焼き入れ硬化層２４を形成した後、上記外輪４の内周面側にまで貫通させたものである。
【００２５】
即ち、図３に示す様に、上記取付孔１７の元となる上記有底の凹孔２７を、上記外輪４の外周面側から直径方向に関して途中まで形成してから、図４に示す様に、この外輪４の外周面部分を、冷却水、冷却油等の冷媒により冷却しつつ、この外輪４を内周面側から加熱して、図４に示す様に、中間部分の外径が小さくなった焼き入れ硬化層２４を形成する。その後、超硬ドリル又はセラミックチップを備えたドリルにより上記凹孔２７の底部を削り取って、図５に示す様に、上記外輪４の外周面側から内周面側にまで貫通した、上記取付孔１７を形成する。上記凹孔２７の底部を加工するのは、上述の様に超硬ドリル又はセラミックチップを備えたドリルの様な、硬い工具により行なう必要がある。但し、本例の場合には、加工代が少ないので、加工作業は容易である。又、同一の工具で生の部分と硬い部分との両方を加工する必要性も少ないので、工具の目づまり等を防止しつつ、能率の良い加工を行なえる。
【００２６】
この様に、同一の工具で生の部分と硬い部分との両方を加工する事を極力避ける為に、上記焼き入れ硬化層２４が上記凹孔２７の底部にまで達する様に、これら焼き入れ硬化層２４の厚さと凹孔２７の深さとの関係を規制する事が好ましい。又、焼き入れ硬化層２４を形成する為の熱処理時に於ける、上記凹孔２７の底部近傍の変形を極力抑える為に、この底部の厚さ（凹孔２７の底面から外輪４の内周面までの距離）は、１mm以上確保する事が好ましい。尚、本例の場合、上述の様に、上記焼き入れ硬化層２４を形成する際に、上記外輪４の外周面を冷媒により冷却するが、この冷媒が上記取付孔１７を通って、この外輪４の内周面に達する事はない。この為、上記外輪４の内周面で上記焼き入れ硬化層２４を形成すべき部分に冷媒が付着する事により、この焼き入れ硬化層２４に焼きむらが生じる事をなくせる。
【００２７】
次に、図６は、やはり請求項１〜２に対応する、本発明の実施の形態の第２例を示している。本例の場合には、外輪４の軸方向中間部で複列の外輪軌道１２、１２（図１〜５）の間部分に形成する凹孔２７ａを、内周面寄り部分が深くなった形状としている。本例の場合には、この様な凹孔２７ａを形成した状態で、上記外輪４の外周面部分を、冷却水、冷却油等の冷媒により冷却しつつ、この外輪４の内周面の所定部位に焼き入れ硬化層を形成した後、この外輪４の内周面を図示しない受型に当接させた状態で、やはり図示しないパンチにより、上記凹孔２７ａの底部２８を打ち抜いて、上記外輪４の外周面側から内周面側にまで貫通した取付孔を形成する。尚、取付孔の内端部で上記パンチにより打ち抜く部分の内径を、この取付孔内に挿入するセンサの先端部の外径に合わせて極力小さくする事により、打ち抜き加工の容易化を図る事も可能である。
【００２８】
次に、図７〜１０は、本発明に関連する参考例の第２例を示している。本参考例の場合には、回転速度検出装置付転がり軸受ユニットを構成する外輪４の内周面の外輪軌道１２、１２及びこれら両外輪軌道１２、１２の間部分の焼き入れ硬化層２４は、この間部分に取付孔１７を形成した後、この取付孔１７の外端開口（外輪４の外周面側開口）を栓２５により密閉した状態で、上記外輪４の外周面部分を、冷却水、冷却油等の冷媒により冷却しつつ形成したものである。
【００２９】
即ち、上記外輪４に上記焼き入れ硬化層２４及び取付孔１７を形成するのに、先ず、図７に示す様に、上記外輪４に焼き入れ硬化層を形成しない、この外輪４が未だ生の状態で、この外輪４の軸方向中間部で上記複列の外輪軌道１２、１２の間部分に、上記取付孔１７を形成する。その後、図８に示す様に、この取付孔１７を、金属、セラミック等の耐熱材料製の栓２５により密閉した状態で、上記外輪４の外周面で上記取付孔１７の近傍を含む軸方向中間部分を冷媒により冷却しつつ、この外輪４の内側に配置した図示しない加熱コイルに通電する等により、この外輪４の内周面を加熱して、上記焼き入れ硬化層２４を形成する。その後、上記栓２５を取り外して、図９に示す様な外輪４とする。本例の場合、上記栓２５の基部と上記取付孔１７に形成した受面２１との間にＯリング２６を設けて、これら栓２５の外周面と取付孔１７の内周面との間に、上記冷媒が入り込まない様にしている。
【００３０】
尚、上記栓２５自体を、ゴム等のエラストマー、或は合成樹脂等の弾性材により造れば、この栓２５自体の弾性に基づき、上記取付孔１７を密閉できる。この様な場合には、図１０に示す様に、栓２５の軸方向寸法を小さくしても良い。更には、栓を、金属又は合成樹脂により、上記取付孔１７内には入り込まない（この取付孔１７よりも大きな）板状に、又は一部が緩く入り込む形状に形成し、別途設けたばね或はバンド等によりこの板状等の栓を、上記外輪４の外周面で上記取付孔１７部分に抑え付け、この取付孔１７を塞いでも良い。この様に、栓２５の軸方向寸法を小さくすれば、上記加熱コイルへの通電時に、上記取付孔１７の内周面で上記栓２５の一部が接触している部分が高温にならずに済む。従って、この栓２５が耐熱材料製でなくても、上記外輪４の内周面の加熱時に、この栓２５が損傷を受ける事はない。
【００３１】
又、上記Ｏリング２６は、上記栓２５を上記取付孔１７内に仮止め可能にしつつ、この栓２５をこの取付孔１７内に容易に着脱自在とする機能も有する。又、上記加熱の際、上記外輪４の両端開口部も、図示しない塞ぎ板等により塞ぎ、この外輪４の内側に上記冷媒が入り込まない様にする事もできる。この為、上記外輪４の内周面で上記焼き入れ硬化層２４を形成すべき部分に冷媒が付着する事により、この焼き入れ硬化層２４に焼きむらが生じる事をなくせる。この様な本例の場合には、上記焼き入れ硬化層２４を形成する以前の、上記間部分が外周面から内周面まで総て生のままの状態で、この間部分に上記取付孔１７を形成する為、この取付孔１７の加工を容易に行なえる。
【００３２】
又、図１１は、請求項３〜４に対応する、本発明の実施の形態の第３例を示している。本例の場合には、外輪４の軸方向中間部で複列の外輪軌道１２、１２の間部分に取付孔１７を、この外輪４の内周面に焼き入れ硬化層を形成する以前に形成する。その後、この外輪４を回転させながら、この外輪４の外周面部分を、図１１に矢印で示す様に、下方から上方に向けて吹き上げる液状の冷媒により冷却しつつ、上記外輪４の内周面を加熱して、上記焼き入れ硬化層を形成する。図１１に矢印で示す、上記液状の冷媒の吹き上げ強さは、上記取付孔１７が図１１に示す様に下方に向いた状態でも、この冷媒がこの取付孔１７を通じて上記外輪４の内側にまで入り込まない程度にする。即ち、上記冷媒がこの外輪４の外周面（下面）にまでは達するが、この外輪４の内周面にまでは達しない程度の強さとする。この様な本例の場合も、上記焼き入れ硬化層を形成する以前の、上記間部分が外周面から内周面まで総て生のままの状態で、この間部分に上記取付孔１７を形成する為、この取付孔１７の加工を容易に行なえる。
【００３３】
更に、図示は省略するが、請求項５〜６に記載した様に、焼き入れ硬化層の形成作業を、外輪に取付孔を形成した後、この外輪の外周面部分を気体冷媒により冷却しつつ行なえば、形成後の取付孔を栓により塞いだり、或は冷媒の吹き付け強さを規制したりする事なく行なえる。この場合に使用する気体冷媒としては、液体窒素を蒸発させて得た低温窒素ガス等が使用可能である。この様な気体冷媒を使用する場合には、上記外輪を回転させる必要はないが、回転させない場合には、気体冷媒をこの外輪の外周面にまんべんなく吹き付けられる様に、外輪の周囲に複数の吹き付けノズルを配置する。
【００３４】
尚、図示の例は、駆動輪（ＦＲ車及びＲＲ車の後輪、ＦＦ車の前輪、４ＷＤ車の全輪）支持用の転がり軸受ユニットに本発明を適用した場合に就いて述べたが、本発明は、従動輪（ＦＲ車及びＲＲ車の前輪、ＦＦ車の後輪）支持用の転がり軸受ユニットにも適用できる。又、本発明の特徴は、外輪の中間部に形成するセンサ支持固定用の取付孔の形成作業を容易に行なえる様にする点にある。回転速度検出装置の種類は、センサ及びエンコーダを含めて、特に限定するものではない。従って、回転速度検出装置は、図示の各例の様な磁気検知式のものに限らず、渦電流式、光電式等、他の構造のものを採用する事もできる。
【００３５】
【発明の効果】
本発明は、以上に述べた通り構成され作用するので、回転速度検出装置付転がり軸受ユニットを構成する外輪の加工作業の容易化により、この回転速度検出装置付転がり軸受ユニットのコスト低減を図れる。
【図面の簡単な説明】
【図１】本発明に関する参考例の第１例を示す断面図。
【図２】外輪のみを取り出して示す断面図。
【図３】本発明の実施の形態の第１例を示す、焼き入れ硬化層を形成する以前の外輪の断面図。
【図４】同じく外輪に焼き入れ硬化層を形成した状態を示す断面図。
【図５】焼き入れ硬化層及び取付孔を形成した外輪の断面図。
【図６】本発明の実施の形態の第２例を示す、図４のＡ部に相当する断面図。
【図７】本発明に関する参考例の第２例を示す、焼き入れ硬化層を形成する以前の外輪の断面図。
【図８】同じく外輪に焼き入れ硬化層を形成する状態を示す断面図。
【図９】焼き入れ硬化層を形成した外輪の断面図。
【図１０】栓の別例を示す、図８と同様の図。
【図１１】本発明の実施の形態の第３例を示す、外輪の断面図。
【符号の説明】
１ハブ本体
２内輪
３ハブ
４外輪
５転動体
６フランジ
７内輪軌道
８段部
９スプライン孔
１０嵌着部
１１エンコーダ
１２外輪軌道
１３保持器
１４取付部
１５シールリング
１６透孔
１７取付孔
１８センサ
１９取付面
２０面取り部
２１受面
２２取付部
２３Ｏリング
２４焼き入れ硬化層
２５栓
２６Ｏリング
２７、２７ａ凹孔
２８底部[0001]
BACKGROUND OF THE INVENTION
  The present invention provides a rolling bearing unit with a rotational speed detection device and a rolling bearing with a rotational speed detection device, which are used for rotatably supporting a vehicle wheel relative to a suspension device and detecting the rotational speed of the wheel. It relates to the improvement of the outer ring constituting the unit.
[0002]
[Prior art]
  A rolling bearing unit is used to rotatably support the wheels of the automobile with respect to the suspension system. Further, in order to control the anti-lock brake system (ABS) and the traction control system (TCS), it is necessary to detect the rotational speed of the wheel. For this reason, the rolling bearing unit with a rotational speed detection device incorporating a rotational speed detection device in the rolling bearing unit supports the wheel rotatably with respect to the suspension device, and detects the rotational speed of the wheel. However, in recent years it has become widely practiced.
[0003]
  In such a rolling bearing unit with a rotational speed detection device, a hub is rotatably supported via a plurality of rolling elements on the inner diameter side of the outer ring. At the same time, fixed in a part of the hub, in the circumferential directionCrawlingThe rotation speed of the encoder whose characteristics are alternately changed at equal intervals can be detected by a sensor supported on a part of the outer ring. Also, with this sensor supported in a mounting hole formed in the axial direction intermediate portion of the outer ring and extending in the diameter direction of the outer ring, the detection portion of the sensor is placed on the outer peripheral surface of the large-diameter cylindrical portion of the encoder. The facing is also widely known in the past, as described in many publications such as JP-A-63-59769, JP-A-6-109027, and JP-A-8-270659. .
[0004]
  When the rolling bearing unit with a rotational speed detection device as described above is used, the outer ring is supported by the suspension device, and a wheel is fixed to a portion of the hub that is detached from the outer ring, and the wheel is fixed to the suspension device. It is supported so that it can rotate freely. When the encoder rotates with the rotation of the wheel, the output of the sensor having the detection unit opposed to the encoder changes. The frequency at which the output of this sensor changes is proportional to the rotational speed of the wheel. Therefore, if the output signal of this sensor is sent to the controller for determining the rotational speed of the wheel, ABS and TCS can be controlled appropriately.
[0005]
[Problems to be solved by the invention]
  In the case of the rolling bearing unit with a rotational speed detection device described in each of the above-mentioned publications, the balance between ensuring the durability of the outer ring and the processability of the mounting hole has not been considered. That is, on the surface of the double row outer ring raceway formed on the inner peripheral surface of the outer ring and a portion in the vicinity of the surface, a hardened hardened layer having a hardness of, for example, Hv 500 or more is provided for the purpose of ensuring the rolling fatigue life of each outer ring raceway. Need to form. In addition, a hardened hardened layer is also formed in a portion between the outer ring raceways of the double row at a part of the inner peripheral surface portion of the outer ring, and it is difficult to plastically deform the portion between these, for example in Utility Model Registration No. 2529597 As is also described, it is conventionally known. In this way, if the intermediate portion is difficult to be plastically deformed, even if an impact load is applied to the outer ring due to the wheel hitting the curbstone, etc., the outer ring is prevented from being plastically deformed, and the rotation including the outer ring is prevented. The durability of the rolling bearing unit with speed detecting device can be improved. Even in such a case, the outer ring has a raw portion that is not quenched and hardened in the vicinity of the outer periphery to ensure the toughness of the outer ring, and the outer ring is cracked based on the impact load. Prevent damage.
[0006]
  However, as described above, when a hardened hardened layer is also formed on the part of the inner ring between the outer ring raceways on a part of the inner ring surface, the mounting holes formed in the outer ring to support and fix the sensor are processed. Becomes difficult.
  In addition, in order to ensure the toughness of the outer ring and to prevent the outer ring from being damaged such as cracks regardless of the impact load that may be applied when the vehicle is running, a part of the outer ring may In order to leave a raw part that has not been hardened by quenching at a portion near the outer diameter of the outer ring, it is necessary to form a hardened hardened layer on the inner peripheral surface of the outer ring while cooling the outer peripheral surface of the outer ring with a refrigerant. is there. In such a case, it is necessary to prevent the refrigerant from entering the inner peripheral surface of the outer ring and causing unevenness in the hardened and hardened layer. However, conventionally, no invention that takes this into account has been known. It was.
  In view of such circumstances, the rolling bearing unit with a rotational speed detection device and the method for processing the outer ring for a rolling bearing unit with a rotational speed detection device according to the present invention include a sensor for an outer ring that is prevented from being deformed by a hardened hardened layer. It was invented to make it possible to form a mounting hole for supporting and fixing the film and to prevent unevenness in the hardened and hardened layer if necessary.
[0007]
[Means for Solving the Problems]
  The rolling bearing unit with a rotational speed detection device, which is the subject of the present invention, has a double-row inner ring raceway on the outer peripheral surface, like the conventionally known rolling bearing unit with a rotational speed detection device. A rotating hub; an outer ring having a double-row outer ring raceway at a position facing the double-row inner ring raceway on an inner peripheral surface; and being supported by a suspension device during use; the inner ring raceway and the outer ring A plurality of rolling elements provided between the raceway and a plurality of rolling elements, and an outer peripheral surface of the intermediate portion of the hub, and fitted and fixed to a portion between the double row inner ring raceways in a circumferential direction.CrawlingAn encoder having characteristics alternately changed at equal intervals and a detector, and supported in a mounting hole provided in an axially intermediate portion of the outer ring in a state where the detector is opposed to the encoder, A sensor that changes the output signal in response to a change in the characteristics of the encoder. A hardened hardened layer is formed on the inner peripheral surface of the outer ring at each outer ring raceway portion and between the outer ring raceways.
[0008]
  In particular, in the rolling bearing unit with a rotational speed detection device of the present invention, in the rolling bearing unit with a rotational speed detection device according to claim 1,The quench hardened layer heats the inner peripheral surface of the outer ring while cooling the outer ring from the outer peripheral surface side with a refrigerant in a state where the mounting hole is formed from the outer peripheral surface side to the middle in the diameter direction. The mounting hole is formed by penetrating to the inner peripheral surface side of the outer ring after forming the quenched and hardened layer. .
[0009]
  And in claim 2The processing method of the outer ring constituting the rolling bearing unit with the rotational speed detection device described is that the mounting hole is formed from the outer peripheral surface side of the outer ring to the middle in the diametrical direction, and then the outer ring is cooled by the refrigerant from the outer peripheral surface side. After this outer ring is heated from the inner peripheral surface side to form a hardened hardened layer, the mounting hole is penetrated to the inner peripheral surface side of the outer ring.
[0010]
  In the rolling bearing unit with a rotational speed detection device according to claim 3,The hardened hardened layer, after forming the mounting hole, heats the inner peripheral surface of the outer ring while cooling the outer peripheral surface portion of the outer ring with a coolant blowing upward from below while rotating the outer ring. Formed.
[0011]
  And claim 4The processing method of the outer ring that constitutes the rolling bearing unit with a rotational speed detection device described in 1), after forming the mounting hole in the portion between the double row outer ring raceways in the axial direction intermediate part of the outer ring, while rotating the outer ring, While cooling the outer peripheral surface portion of the outer ring with the refrigerant blown upward from below, the inner peripheral surface of the outer ring is heated to form a hardened hardening layer.
[0012]
  Furthermore,Claim 5In the rolling bearing unit with a rotational speed detection device described in 1), after the hardened hardened layer has formed the mounting hole, the outer peripheral surface portion of the outer ring is cooled with a gaseous refrigerant while the inner periphery of the outer ring is cooled. The surface is formed by heating.
  AndClaim 6The processing method of the outer ring constituting the rolling bearing unit with the rotational speed detection device described in 1) is to form the mounting hole in the portion between the double row outer ring raceways in the axial direction intermediate portion of the outer ring, and then to change the outer peripheral surface portion of the outer ring. While cooling with a gaseous refrigerant, the inner peripheral surface of the outer ring is heated to form a hardened and hardened layer.
[0013]
[Action]
  The rolling bearing unit with a rotational speed detection device of the present invention configured to include the outer ring constructed as described above supports the wheel rotatably with respect to the suspension device, and the operation when detecting the rotational speed of the wheel is as follows. This is the same as the case of a rolling bearing unit with a rotational speed detection device that has been generally known.
[0014]
  Particularly, according to the rolling bearing unit with a rotational speed detection device and the processing method of the outer ring for the rolling bearing unit with a rotational speed detection device of the present invention, the sensor is supported and fixed to the outer ring which is prevented from being deformed by a hardened hardened layer. Mounting holes can be formed. For this reason, it is possible to realize a rolling bearing unit with a rotational speed detection device that includes an outer ring that is not easily deformed by an impact, and that supports and fixes a sensor in a mounting hole formed in an axially intermediate portion of the outer ring.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
  1 and 2 show reference examples related to the present invention.First exampleIs shown. The rolling bearing unit constituting the rolling bearing unit with a rotational speed detecting device of this reference example includes a hub 3 formed by combining the hub main body 1 and the inner ring 2, an outer ring 4, and a plurality of rolling elements 5, 5. . Out of these, the outer end of the outer peripheral surface of the hub main body 1 (outside means the side that is outward in the width direction when assembled to the automobile, and is the left side of FIGS. 1 and 2. The flange 6 for supporting the wheel is provided on the right side of FIGS. An inner ring raceway 7 is formed on the outer peripheral surface of the intermediate portion of the hub body 1. The inner ring raceway 7 may be formed directly on the outer peripheral surface of the intermediate portion of the hub body 1 or may be formed on the outer peripheral surface of a separate inner ring that is externally fitted on the outer peripheral surface of the hub body 1.
[0016]
  Further, a step portion 8 that is recessed inward in the diameter direction from the outer peripheral surface of the hub body 1 is provided at the inner end portion of the hub body 1 concentrically with the hub body 1 over the entire circumference. Then, the inner ring 2 in which another inner ring raceway 7 is formed on the outer peripheral surface is externally fixed to the step portion 8 by an interference fit. Further, the inner end portion of the inner ring 2 protrudes inward in the axial direction from the inner end surface of the hub body 1 in the state of being fitted and fixed in this manner. The inner end surface of the inner ring 2 is in contact with a stepped surface of a constant velocity joint (not shown) in an assembled state to the vehicle. Further, the spline shaft attached to the constant velocity joint is inserted into the spline hole 9 provided at the center of the hub body 1 in the assembled state to the vehicle. Then, a nut (not shown) is also screwed into a male thread portion provided at a portion protruding outward from the outer end surface of the hub body 1 at the tip end portion of the spline shaft, and further tightened. Based on the tightening of the nut, the step surface of the constant velocity joint strongly presses the inner end surface of the inner ring 2 and prevents the inner ring 2 from coming out of the step portion 8. Of the intermediate portion of the hub body 1 formed to have a diameter larger than that of the step portion 8, the end portion on the step portion 8 side has a fitting portion slightly smaller in diameter than the intermediate portion of the hub body 1. 10 is provided. The outer diameter of the fitting portion 10 is slightly larger than the inner diameter of the encoder 11 to be described later in a free state so that the encoder 11 can be fitted and fixed by interference fitting. Further, the outer diameter of the encoder 11 is set to be equal to or smaller than the outer diameter of the outer portion of the hub body 1 than the fitting portion 10 in a state where the outer diameter is fixed to the fitting portion 10.
[0017]
  Further, double-row outer ring raceways 12 and 12 are formed on the inner peripheral surface of the outer ring 4 so as to face the inner ring raceways 7 and 7, respectively. A plurality of rolling elements 5 and 5 are provided between the inner ring raceways 7 and 7 and the outer ring raceways 12 and 12, respectively, so as to be freely rollable while being held by the cages 13 and 13, respectively. The hub body 1 and the inner ring 2 are rotatably supported inside the outer ring 4. In the illustrated example, balls are used as the rolling elements 5 and 5. However, in the case of a rolling bearing unit for automobiles that is heavy in weight, tapered rollers may be used as these rolling elements. Further, on the outer peripheral surface near the inner end of the outer ring 4, an outward flange-like attachment portion 14 for attaching the outer ring 4 to a suspension device is provided. Further, gaps between the opening portions at both ends of the outer ring 4 and the outer peripheral surface of the intermediate portion of the hub body 1 and the outer peripheral surface of the inner end portion of the inner ring 2 are closed by seal rings 15 and 15, respectively.
[0018]
  An encoder 11 is externally fitted and fixed concentrically to the fitting portion 10 at a part of the outer peripheral surface of the intermediate portion of the hub body 1. The encoder 11 is formed in a cylindrical shape as a whole by a magnetic metal plate such as a steel plate, and the rolling elements 5 and 5 provided in the double row by being fitted and fixed to the fitting portion 10 by interference fitting. It is arranged in the part between the columns. In addition, by forming a plurality of through holes 16, 16 at equal intervals in the circumferential direction in the intermediate portion in the axial direction of the encoder 11, the magnetic characteristics of the outer peripheral surface of the encoder 11 can be changed in the circumferential direction. In the meantime, it is changed alternately and at equal intervals.
[0019]
  On the other hand, a mounting hole 17 is formed in the axially intermediate portion of the outer ring 4 at a position radially outward of the encoder 11 so that the inner peripheral surface and the outer peripheral surface of the outer ring 4 communicate with each other. A sensor 18 in which a detection element is embedded in a synthetic resin is inserted and fixed in the mounting hole 17, and the detection unit provided on the front end surface (lower end surface in FIG. 1) of the sensor 18 is connected to the encoder. It is made to oppose the outer peripheral surface of 11 through the micro clearance gap. With the sensor 18 inserted and fixed in the mounting hole 17 in this manner, the sensor 18 can detect the rotational speed of the encoder 11.
[0020]
  A flat mounting surface 19 is formed on the outer peripheral surface of the outer ring 4 and around the outer end opening of the mounting hole 17. The flat mounting surface 19 exists in a direction perpendicular to the central axis of the mounting hole 17. . A conical concave chamfered portion 20 and a receiving surface 21 are formed in this order from the mounting surface 19 side in a continuous portion between the mounting surface 19 and the inner peripheral surface of the mounting hole 17. On the other hand, a mounting portion 22 is fixed to the base end portion (upper end portion in FIG. 1) of the sensor 18, and the mounting portion 22 is attached to the outer ring 4 by a screw (not shown) inserted through the end portion of the mounting portion 22. Bonded and fixed. In this state, the O-ring 23 externally fitted to the base end portion of the sensor 18 is elastically compressed between the outer peripheral surface of the base end portion and the inner peripheral surface of the receiving surface 21, thereby the sensor 18. The part to which is attached is sealed, and foreign matter such as rainwater is prevented from entering the outer ring 4 through the mounting hole 17.
[0021]
  Further, a hardened hardened layer 24 having a hardness of, for example, Hv 500 or more is formed on the inner peripheral surface of the outer ring 4 on each of the outer ring raceways 12, 12 and between the outer ring raceways 12, 12. A portion of the hardened and hardened layer 24 that is present on the outer ring raceways 12 and 12 is independent of the load repeatedly applied from the rolling surfaces of the rolling elements 5 and 5. Securing the rolling fatigue life of the part. On the other hand, the intermediate part existing in the part between the outer ring raceways 12 and 12 in the remaining part of the hardened and hardened layer 24 makes the part difficult to plastically deform, so that the wheel rides on the curb, etc. Regardless of the impact load applied from the rolling elements 5 and 5, it is possible to prevent the intermediate portion of the outer ring 4 from being plastically deformed. The quench hardened layer 24 is formed by heating the outer ring 4 from the inner peripheral surface side while cooling the outer peripheral surface portion of the outer ring 4 with a coolant such as cooling water or cooling oil (described later).Of the present inventionOf the embodimentFirst exampleThe same applies to the following). Thus, the reason why the quench hardened layer 24 is formed while cooling the outer peripheral surface portion of the outer ring 4 is to prevent the outer diameter of the outer ring 4 from being excessively increased. The outer ring surface side is prevented from becoming hard, the toughness of the outer ring 4 is secured, and the outer ring 4 is damaged such as cracks regardless of the impact load that may be applied during the operation of the automobile. This is to prevent things. At the same time, the thickness of the hardened hardened layer 24 that is difficult to process the mounting hole 17 is reduced to facilitate the processing of the mounting hole 17.
[0022]
  At the intermediate portion in the axial direction of the outer ring 4 having the hardened hardened layer 24 as described above formed on the inner peripheral surface, the mounting hole 17 is formed between the outer ring raceways 12 and 12, and the hardened hardened layer 24 is formed. After that, it is formed by a carbide drill or a drill having a ceramic tip. Among the above-mentioned portions, the hardened hardened layer 24 portion present near the inner peripheral surface is hard, for example, having a hardness of Hv 500 or more, but according to a drill equipped with a carbide drill or a ceramic tip, the mounting hole is sufficiently formed. 17 can be processed. Therefore, the mounting hole 17 for supporting and fixing the sensor 18 can also be formed in the outer ring 4 which is prevented from being deformed by the quench hardened layer 24. When the mounting hole 17 is cut by the carbide drill or the drill provided with the ceramic tip, the cutting oil is poured into at least the cutting portion to cool and lubricate the cutting portion. The lubricating oil used at this time is preferably water-insoluble. In addition, since the heat generated when drilling the hardened hardened layer 24 is large, not only the cutting oil is poured as described above, but also the processing speed (rotation speed of the drill) is increased. It is preferable to slow down compared with the case of drilling a part. That is, the aboveBy drillThe cutting speed of the mounting hole 17 is 20 m / min or less, more preferably when the inner diameter of the mounting hole 17 (= the outer diameter of the drill) is about 11 to 13 mm, expressed as the speed of the outer peripheral surface of the drill. 10 m / min or less. In addition, the cutting speed in the case of making the said attachment hole 17 in the raw part which is not a hardening hardening layer is about 35-41 m / min.
[0023]
  As mentioned aboveThis reference exampleIn the case of the rolling bearing unit with the rotational speed detection device, the wheel fixed to the flange 6 provided at the outer end of the hub body 1 can be rotatably supported with respect to the suspension device supporting the outer ring 4. Further, when the encoder 11 that is externally fitted and fixed to the hub body 1 rotates with the rotation of the wheel, the vicinity of the detection portion provided on the front end surface of the sensor 18 is penetrated in the intermediate portion in the axial direction of the encoder 11. The holes 16, 16 and the pillars existing between the through holes 16, 16 adjacent in the circumferential direction pass alternately. As a result, the amount (density) of the magnetic flux flowing through the sensor 18 changes, and the output of the sensor 18 changes. The frequency at which the output of the sensor 18 changes in this way is proportional to the rotational speed of the wheel. Therefore, if the output of the sensor 18 is sent to a controller (not shown), the ABS and TCS can be appropriately controlled.
[0024]
  Next, FIGS. 3 to 5 show a first example of an embodiment of the present invention corresponding to claims 1 and 2. In the case of this example, the outer ring raceways 12 and 12 on the inner peripheral surface of the outer ring 4 constituting the rolling bearing unit with the rotational speed detection device, and bothOuter ring racewayThe quench hardening layer 24 between the portions 12 and 12 is formed in a state in which a bottomed concave hole 27 serving as a base of the attachment hole 17 is formed from the outer peripheral surface side of the portion between these portions. The mounting hole 17 is formed by penetrating to the inner peripheral surface side of the outer ring 4 after forming the hardened hardening layer 24.
[0025]
  That is, as shown in FIG. 3, after forming the bottomed concave hole 27 that becomes the base of the mounting hole 17 from the outer peripheral surface side of the outer ring 4 to the middle in the diametrical direction, as shown in FIG. While cooling the outer peripheral surface portion of the outer ring 4 with a coolant such as cooling water and cooling oil, the outer ring 4 is heated from the inner peripheral surface side, so that the outer diameter of the intermediate portion is small as shown in FIG. The quench hardening layer 24 thus formed is formed. Thereafter, the bottom of the concave hole 27 is scraped off with a carbide drill or a drill having a ceramic chip, and the mounting hole penetrates from the outer peripheral surface side to the inner peripheral surface side of the outer ring 4 as shown in FIG. 17 is formed. The bottom of the concave hole 27 needs to be processed with a hard tool such as a carbide drill or a drill with a ceramic tip as described above. However, in this example, the machining work is easy because the machining cost is small. Further, since there is little need to process both the raw part and the hard part with the same tool, efficient machining can be performed while preventing clogging of the tool.
[0026]
  In this way, in order to avoid processing the raw part and the hard part with the same tool as much as possible, the quench hardening layer 24 reaches the bottom of the concave hole 27 so that the quench hardening is performed. It is preferable to regulate the relationship between the thickness of the layer 24 and the depth of the concave hole 27. Further, in order to suppress deformation near the bottom of the concave hole 27 as much as possible during the heat treatment for forming the quench hardening layer 24, the thickness of the bottom (from the bottom surface of the concave hole 27 to the inner peripheral surface of the outer ring 4). Is preferably 1 mm or more. In the case of this example, as described above, the outer peripheral surface of the outer ring 4 is cooled by a refrigerant when the quench hardened layer 24 is formed. This refrigerant passes through the mounting hole 17 and passes through the outer ring 4. The inner peripheral surface of 4 is never reached. For this reason, it is possible to eliminate the occurrence of uneven burning in the quenched and hardened layer 24 when the refrigerant adheres to the portion of the inner peripheral surface of the outer ring 4 where the hardened and hardened layer 24 is to be formed.
[0027]
  Next, FIG.Claims 1-2Corresponding to the embodiment of the present inventionSecond exampleIs shown. In the case of this example, the concave hole 27a formed in the portion between the double-row outer ring raceways 12 and 12 (FIGS. 1 to 5) at the intermediate portion in the axial direction of the outer ring 4 has a shape in which the portion closer to the inner peripheral surface becomes deeper. It is said. In the case of this example, the outer peripheral surface portion of the outer ring 4 is cooled by a coolant such as cooling water or cooling oil in a state where such a concave hole 27a is formed, and the predetermined inner peripheral surface of the outer ring 4 is predetermined. After forming a hardened and hardened layer at the site, the bottom portion 28 of the concave hole 27a is punched out with a punch (not shown) in a state where the inner peripheral surface of the outer ring 4 is in contact with a receiving die (not shown). A mounting hole penetrating from the outer peripheral surface side to the inner peripheral surface side is formed. Note that the punching process can be facilitated by making the inner diameter of the punched hole at the inner end of the mounting hole as small as possible in accordance with the outer diameter of the tip of the sensor inserted into the mounting hole. Is possible.
[0028]
  Next, FIGS.Second example of reference example related to the present inventionIs shown.This reference exampleIn this case, the outer ring raceways 12 and 12 on the inner peripheral surface of the outer ring 4 constituting the rolling bearing unit with a rotational speed detection device and the hardened hardened layer 24 between these outer ring raceways 12 and 12 are located between these two portions. After the mounting hole 17 is formed, the outer peripheral surface portion of the outer ring 4 is made of cooling water, cooling oil or the like with the outer end opening (opening on the outer peripheral surface side of the outer ring 4) of the mounting hole 17 sealed with the plug 25. It is formed while cooling with a refrigerant.
[0029]
  That is, in order to form the quenched and hardened layer 24 and the mounting hole 17 in the outer ring 4, first, as shown in FIG. 7, no hardened and hardened layer is formed in the outer ring 4. In this state, the mounting hole 17 is formed in a portion between the double-row outer ring raceways 12 and 12 at an intermediate portion in the axial direction of the outer ring 4. Thereafter, as shown in FIG. 8, the mounting hole 17 is formed by a plug 25 made of a heat-resistant material such as metal or ceramic.SealedIn this state, the outer ring 4 is energized by, for example, energizing a heating coil (not shown) disposed inside the outer ring 4 while cooling an axial intermediate portion including the vicinity of the mounting hole 17 on the outer peripheral surface of the outer ring 4 with a refrigerant. The inner peripheral surface is heated to form the quenched and hardened layer 24. Thereafter, the stopper 25 is removed to obtain an outer ring 4 as shown in FIG.In this example,An O-ring 26 is provided between the base of the plug 25 and the receiving surface 21 formed in the mounting hole 17, and the refrigerant enters between the outer peripheral surface of the plug 25 and the inner peripheral surface of the mounting hole 17. As if notis doing.
[0030]
  still,If the plug 25 itself is made of an elastomer such as rubber or an elastic material such as synthetic resin, the mounting hole 17 can be sealed based on the elasticity of the plug 25 itself. In such a case, the axial dimension of the plug 25 may be reduced as shown in FIG. Further, the plug is formed of a metal or synthetic resin into a plate shape that does not enter the mounting hole 17 (larger than the mounting hole 17) or a part of the plug that enters loosely, or a separately provided spring or The plate-like stopper may be pressed against the mounting hole 17 portion on the outer peripheral surface of the outer ring 4 by a band or the like, and the mounting hole 17 may be closed. In this way, if the axial dimension of the plug 25 is reduced, the portion of the plug 25 that is in contact with the inner peripheral surface of the mounting hole 17 does not become hot when the heating coil is energized. That's it. Therefore, even if the plug 25 is not made of a heat-resistant material, the plug 25 is not damaged when the inner peripheral surface of the outer ring 4 is heated.
[0031]
  or,The O-ring 26 also has a function of making the plug 25 easily detachable in the mounting hole 17 while allowing the plug 25 to be temporarily fixed in the mounting hole 17. Further, at the time of the heating, both end openings of the outer ring 4 can be closed by a not-shown closing plate or the like so that the refrigerant does not enter the outer ring 4. For this reason, it is possible to eliminate the occurrence of uneven burning in the quenched and hardened layer 24 when the refrigerant adheres to the portion of the inner peripheral surface of the outer ring 4 where the hardened and hardened layer 24 is to be formed. In the case of this example, the mounting hole 17 is formed in the intermediate portion with the intermediate portion remaining from the outer peripheral surface to the inner peripheral surface before the quench-hardened layer 24 is formed. Since it is formed, the mounting hole 17 can be easily processed.
[0032]
  Also, FIG.Claims 3-4Corresponding to the embodiment of the present inventionThird exampleIs shown. In the case of this example, the mounting hole 17 is formed in the middle portion of the outer ring 4 between the double row outer ring raceways 12 and 12 before the hardened layer is formed on the inner peripheral surface of the outer ring 4. To do. Thereafter, while rotating the outer ring 4, the outer peripheral surface portion of the outer ring 4 is cooled by a liquid refrigerant blown upward from below as indicated by arrows in FIG. Is heated to form the quenched and hardened layer. The blowing strength of the liquid refrigerant indicated by an arrow in FIG. 11 is such that the refrigerant reaches the inside of the outer ring 4 through the mounting hole 17 even when the mounting hole 17 faces downward as shown in FIG. Do not enter. That is, the refrigerant has such strength that it reaches the outer peripheral surface (lower surface) of the outer ring 4 but does not reach the inner peripheral surface of the outer ring 4. In the case of this example as well, the mounting hole 17 is formed in the intermediate portion in a state where the intermediate portion before the quenching hardened layer is formed is entirely raw from the outer peripheral surface to the inner peripheral surface. Therefore, the mounting hole 17 can be easily processed.
[0033]
  Furthermore, although illustration is omitted,Claims 5-6As described above, if the hardening hardened layer is formed by forming a mounting hole in the outer ring and then cooling the outer peripheral surface portion of the outer ring with a gas refrigerant, the formed mounting hole is closed with a plug. Or it can be done without regulating the spraying strength of the refrigerant. As the gaseous refrigerant used in this case, low-temperature nitrogen gas obtained by evaporating liquid nitrogen or the like can be used. When such a gas refrigerant is used, it is not necessary to rotate the outer ring. However, if the outer ring is not rotated, a plurality of sprays can be applied around the outer ring so that the gas refrigerant can be sprayed evenly on the outer peripheral surface of the outer ring. Place the nozzle.
[0034]
  In the illustrated example, the present invention is applied to a rolling bearing unit for supporting driving wheels (rear wheels of FR and RR vehicles, front wheels of FF vehicles, all wheels of 4WD vehicles). The present invention can also be applied to a rolling bearing unit for supporting driven wheels (front wheels of FR vehicles and RR vehicles, rear wheels of FF vehicles). Further, the present invention is characterized in that it is possible to easily perform a work for forming a mounting hole for fixing and supporting a sensor formed in an intermediate portion of the outer ring. There are no particular limitations on the type of rotational speed detection device, including sensors and encoders. Therefore, the rotational speed detection device is not limited to the magnetic detection type as shown in the illustrated examples, but may be of another structure such as an eddy current type or a photoelectric type.
[0035]
【The invention's effect】
  Since the present invention is configured and operates as described above, the cost of the rolling bearing unit with a rotational speed detecting device can be reduced by facilitating the processing work of the outer ring constituting the rolling bearing unit with the rotational speed detecting device.
[Brief description of the drawings]
FIG. 1 is a reference example of the present invention.First exampleFIG.
FIG. 2 is a sectional view showing only an outer ring.
FIG. 3 shows an embodiment of the present invention.First exampleSectional drawing of the outer ring | wheel before forming a hardening hardening layer which shows these.
FIG. 4 is a cross-sectional view showing a state where a hardened hardening layer is similarly formed on the outer ring.
FIG. 5 is a cross-sectional view of an outer ring in which a hardened hardening layer and a mounting hole are formed.
FIG. 6 shows an embodiment of the present invention.Second exampleSectional drawing equivalent to the A section of FIG.
FIG. 7Second example of reference exampleSectional drawing of the outer ring | wheel before forming a hardening hardening layer which shows these.
FIG. 8 is a cross-sectional view showing a state where a hardened hardening layer is similarly formed on the outer ring.
FIG. 9 is a cross-sectional view of an outer ring on which a hardened hardening layer is formed.
FIG. 10 is a view similar to FIG. 8, showing another example of the stopper.
FIG. 11 shows an embodiment of the present invention.Third exampleSectional drawing of an outer ring | wheel which shows.
[Explanation of symbols]
    1 Hub body
    2 inner ring
    3 Hub
    4 outer ring
    5 Rolling elements
    6 Flange
    7 Inner ring raceway
    8 steps
    9 Spline hole
  10 fitting part
  11 Encoder
  12 Outer ring raceway
  13 Cage
  14 Mounting part
  15 Seal ring
  16 Through hole
  17 Mounting hole
  18 sensors
  19 Mounting surface
  20 Chamfer
  21 Reception surface
  22 Mounting part
  23 O-ring
  24 Hardened and hardened layer
  25 stoppers
  26 O-ring
  27, 27a concave hole
  28 Bottom

Claims

It has a double-row inner ring track on the outer peripheral surface and rotates with the wheel when in use, and a double-row outer ring track at a position facing the double-row inner ring track on the inner peripheral surface. An outer ring that is supported and does not rotate; a plurality of rolling elements provided between the inner ring raceways and the outer ring raceways; and a plurality of inner ring raceways on the outer peripheral surface of the intermediate portion of the hub. An encoder that is externally fitted and fixed to the intermediate portion, has an encoder whose characteristics are changed alternately and at equal intervals in the circumferential direction, and a detector, and the outer ring of the outer ring is in a state of being opposed to the encoder. A sensor that is supported in a mounting hole provided in an intermediate portion in the axial direction and changes an output signal in response to a change in the characteristics of the encoder, and the outer ring raceway portions and the two outer rings are arranged on the inner peripheral surface of the outer ring. Rotational speed detection with hardened hardened layer formed between the tracks In the rolling bearing unit with a device, the hardened hardened layer is formed by cooling the outer ring from the outer peripheral surface side with a refrigerant while the mounting hole is formed from the outer peripheral surface side of the outer ring to the middle in the diameter direction. It is formed by heating the inner peripheral surface of the outer ring, and the mounting hole is formed by penetrating to the inner peripheral surface side of the outer ring after forming the quenched and hardened layer. Rolling bearing unit with rotation speed detector.

A method for processing an outer ring constituting the rolling bearing unit with a rotational speed detection device according to claim 1, wherein the mounting hole is formed from the outer peripheral surface side of the outer ring to the middle in the diametrical direction, and then the outer ring is formed on the outer peripheral surface side. A rolling bearing unit with a rotational speed detection device that heats the outer ring from the inner peripheral surface side while cooling with a refrigerant to form a hardened hardened layer and then penetrates the mounting hole to the inner peripheral surface side of the outer ring. Processing method for outer ring.

It has a double-row inner ring track on the outer peripheral surface and rotates with the wheel when in use, and a double-row outer ring track at a position facing the double-row inner ring track on the inner peripheral surface. An outer ring that is supported and does not rotate; a plurality of rolling elements provided between the inner ring raceways and the outer ring raceways; and a plurality of inner ring raceways on the outer peripheral surface of the intermediate portion of the hub. An encoder that is externally fitted and fixed to the intermediate portion, has an encoder whose characteristics are changed alternately and at equal intervals in the circumferential direction, and a detector, and the outer ring of the outer ring is in a state of being opposed to the encoder. A sensor that is supported in a mounting hole provided in an intermediate portion in the axial direction and changes an output signal in response to a change in the characteristics of the encoder, and the outer ring raceway portions and the two outer rings are arranged on the inner peripheral surface of the outer ring. Rotational speed detection with hardened hardened layer formed between the tracks In the rolling bearing unit with a device, after the formation of the mounting hole, the hardened hardened layer is cooled by a coolant blowing up the outer peripheral surface portion of the outer ring while rotating the outer ring. A rolling bearing unit with a rotational speed detecting device, wherein the inner peripheral surface of the outer ring is formed by heating.

A method for processing an outer ring constituting a rolling bearing unit with a rotational speed detecting device according to claim 3 , wherein an attachment hole is formed in a portion between the double row outer ring raceways at an axially intermediate portion of the outer ring, and then the outer ring is formed. A rolling bearing with a rotational speed detecting device that forms a hardened hardened layer by heating the inner peripheral surface of the outer ring while cooling the outer peripheral surface portion of the outer ring with a refrigerant blown upward from below while rotating the outer ring. Processing method for outer ring for unit.

It has a double-row inner ring raceway on the outer peripheral surface, and a hub that rotates together with the wheels during use, and a double-row outer ring raceway at a position facing the double-row inner ring raceway on the inner peripheral surface. A non-rotating outer ring supported, a plurality of rolling elements provided in a freely rotatable manner between each of the inner ring raceways and the outer ring raceways, and the double row inner ring raceways on the outer peripheral surface of the intermediate portion of the hub. An encoder that is externally fitted and fixed to the intermediate portion, has an encoder whose characteristics are changed alternately and at equal intervals in the circumferential direction, and a detector, and the outer ring of the outer ring is in a state of being opposed to the encoder. A sensor that is supported in a mounting hole provided in an intermediate portion in the axial direction and changes an output signal in response to a change in the characteristics of the encoder, and the outer ring raceway portions and the two outer rings are arranged on the inner peripheral surface of the outer ring. Rotational speed detection with hardened hardened layer formed between the tracks In the rolling bearing unit with a device, the hardened hardening layer is formed by forming the mounting hole and then heating the inner peripheral surface of the outer ring while cooling the outer peripheral surface portion of the outer ring with a gas refrigerant. A rolling bearing unit with a rotational speed detector characterized by

6. A method of processing an outer ring constituting a rolling bearing unit with a rotational speed detection device according to claim 5 , wherein after forming a mounting hole in a portion between the double row outer ring raceways at an axially intermediate portion of the outer ring, the outer ring A method of processing an outer ring for a rolling bearing unit with a rotational speed detection device, wherein the outer peripheral surface portion of the outer ring is cooled with a gaseous refrigerant and the inner peripheral surface of the outer ring is heated to form a hardened hardened layer.