JP4411778B2

JP4411778B2 - Steering column bearing and bearing device using this bearing

Info

Publication number: JP4411778B2
Application number: JP2000367613A
Authority: JP
Inventors: 高志堀口
Original assignee: Oiles Corp
Current assignee: Oiles Corp
Priority date: 2000-12-01
Filing date: 2000-12-01
Publication date: 2010-02-10
Anticipated expiration: 2020-12-01
Also published as: JP2002168251A

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車のステアリングコラムシャフトを支承するステアリングコラム用軸受及びこの軸受を用いた軸受装置に関する。
【０００２】
【従来の技術】
従来から自動車のステアリングコラムシャフトを支承するステアリングコラム用軸受としては、ボールベアリング又は合成樹脂からなる滑り軸受が使用されている。一般に、自動車のステアリングコラムシャフトを支承する軸受に対しては、荷重や速度などの回転条件はさほど厳しくないが、アイドリング時等にコラムシャフトに作用する振動を吸収する振動吸収性や摩擦トルクの安定性が要求される。ボールベアリングでは、摩擦トルクは安定しているものの振動吸収性に劣り、またボールベアリングを固定するハウジング及びボールベアリングに支承されるコラムシャフトの寸法精度を高精度に仕上げる必要があるため、ベアリング自体の高価な点に加えて加工コストも高くなるという問題がある。
【０００３】
合成樹脂からなる滑り軸受は、上記ボールベアリングに比べ、価格が安く、振動吸収性に優れるという利点を有するものの、滑り軸受とコラムシャフトとの間に適度のクリアランス（軸受隙間）を必要とするため、コラムシャフトに生じる振動により該シャフトと軸受との間に衝突音を発生し、自動車を運転する者に不快音として伝達されるという問題がある。この衝突音の発生を抑制するべくクリアランスを小さくするとスティッククスリップ現象を生じ、摩擦トルクの安定性を阻害するという問題が生じる。
【０００４】
上記に鑑み本出願人は、先に実願平４−５４４１１号（登録第２５７６８２０号：以下「先行技術」という）において、ステアリング操作時（ハンドル回転時）にはコラムシャフトに作用する負荷を軸受により円滑に支承し、アイドリング時等コラムシャフトに負荷が加わらない状態においては、該シャフトに作用する振動を吸収することができるステアリングコラム用軸受装置を提案した。
【０００５】
この先行技術を図７及び図８によって説明する。ステアリングコラム用軸受装置１は、ゴム弾性体又は弾性を有する合成樹脂からなるアウターブッシュ２及びアウターブッシュ２の内面に挿入されるインナーブッシュ３から構成された軸受４と、軸受４を圧入固定するハウジング５と、軸受４に支承されるコラムシャフト６とから成っている。アウターブッシュ２は、その外周面にブッシュの軸線方向に沿いかつ円周方向全周にわたって形成された複数個の凸条部１１を備えた外輪１２と、外輪１２の内面において外輪１２の軸方向に延設された複数個の支持脚１３によって一体的に連結された内輪１４とを具備している。内輪１４は、内面１５の一方の端部に径方向内側にインナーブッシュ３の内径より僅かに小さい内径をもって突出して円周方向にわたって形成された環状リップ部１６と、該環状リップ部１６と連続する拡径円筒部１７と、該環状リップ部１６と軸線方向に所定間隔隔てた拡径円筒部１７の円周方向の一部もしくは全周にインナーブッシュ３の内径より大きく外径より小さい内径の係止突条部１８とを具備している。インナーブッシュ３は、アウターブッシュ２の内輪１４の内面の環状リップ部１６と係止突条部１８との間の拡径円筒部１７内に挿入保持されており、インナーブッシュ３を保持したアウターブッシュ２は、その外輪１２の外周面の凸条部１１においてハウジング５内に圧入固定され、コラムシャフト６は、アウターブッシュ２の内輪１４の内面の環状リップ部１６に締代をもって摺接し、インナーブッシュ３の内周面とは所定のクリアランス（軸受隙間）を保持して支承されている。
【０００６】
【発明が解決しようとする課題】
上述した先行技術からなるステアリングコラム用軸受装置１は、前述した従来技術からなる問題点を解決し、ステアリング操作時にはコラムシャフト６に作用する負荷を軸受４により円滑に支承し、アイドリング時等コラムシャフト６に負荷が加わらない状態においてはコラムシャフト６に作用する振動を吸収することができるものである。しかしながら、軸受４をハウジング５に対し軸方向の抜け止め及び円周方向の回り止めを目的として、強固に圧入する場合、軸受４は、その外輪１２の外周面において圧入されることになるが、外輪１２と内輪１４とは、その軸方向に延設された複数個の支持脚１３によって連結されているので、圧入力が支持脚１３部分の対応する外輪１２の外周面と支持脚１３間の部分に対応する外輪１２の外周面とでは異なり、コラムシャフト６を支持する内輪１４の拡径円筒部１７に保持されたインナーブッシュ３に当該圧入力が均等に作用せず、インナーブッシュ３の内径寸法精度（真円度）に悪影響を及ぼすという問題がある。
【０００７】
また、ハウジング５を車体側に固定するための部材（ブラケット）を溶接加工によりハウジング５の外周面に取付ける場合、該溶接加工による溶接ひずみがハウジング５の内径寸法精度（真円度）に悪影響をもたらし、ハウジング５に固定される軸受４のインナーブッシュ３の内径寸法精度（真円度）はさらに悪化することになる。軸受４のインナーブッシュ３の内径寸法精度（真円度）の良否は、インナーブッシュ３とインナーブッシュ３に支承されるコラムシャフト６との円滑な摺動に影響を与え、これの悪化は当該円滑な摺動を妨げる結果となり、極力避けなければならない問題である。
【０００８】
本発明は、上記問題点を解決するべくなされたもので、その目的とするところは、インナーブッシュの摺動部位の内径寸法精度に影響を及ぼすことがなく、コラムシャフトを円滑に支承し、ステアリング操作をよりスムースに行わせることができるステアリングコラム用軸受及びこの軸受を用いた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】
本発明の第一の態様のステアリングコラム用軸受は、弾性を有する合成樹脂製のアウターブッシュとインナーブッシュと合成樹脂製スリーブとからなり、ここで、アウターブッシュは、円筒内周面の一方の端部近傍に円周方向に沿い、かつ径方向に突設されたリップ部及び該リップ部と軸方向に所定間隔隔てて円周方向に沿って突設され、該リップ部及び円筒内周面と協同して円筒凹部を画定する係止突条部を具備した内輪と、外周面に軸方向に沿う突条部を円周方向に複数個具備した外輪と、円周方向に伸びる外縁では内輪の円筒凹部に対応しない外周面に、円周方向に伸びる内縁では当該外周面に対応する外輪の内周面に夫々一体的に連結された支持脚と、該内輪のリップ部に対応する外周面から軸方向に沿って支持脚まで延び、内輪の外周面、外輪の内周面及び支持脚の夫々に一体的に連結された少なくとも三本の補強リブとを具備しており、インナーブッシュは、内輪の円筒凹部に挿入保持され、少なくとも内周面が合成樹脂で形成された円筒ブッシュからなり、合成樹脂製スリーブは、円筒部と、該円筒部の一方の端部に設けられた環状鍔部と、該円筒部の内周面に設けられていると共に、該内周面の内径よりも小さい内径の縮径部とを具備しており、該合成樹脂製スリーブは、該円筒部の外周面を該円筒ブッシュの内周面に摺動自在に接触させて、該環状鍔部を前記内輪のリップ部と該円筒凹部に挿入保持された円筒ブッシュの端面との間に挿入させて内輪内に配されていることを特徴とする。
【００１０】
アウターブッシュを形成する弾性を有する合成樹脂としては、柔軟であってかつ強靭であり、概ねショア硬さ（Ｄ型）４０〜６０、反発弾性値（ＪＩＳ−Ｋ６３０１）５０〜８０を有していてゴム状の弾性挙動を残存しているもので、例えばポリエステル・エーテル共重合体又はポリウレタン等を好ましいものとして提示し得る。また、スリーブを形成する合成樹脂としては、ポリアセタール樹脂、ポリアミド樹脂、ポリオレフィン樹脂等を好ましいものとして提示し得る。
【００１１】
第一の態様のステアリングコラム用軸受によれば、コラムシャフトは、合成樹脂製スリーブの円筒部の内周面に形成された縮径部に締代をもって挿入されることになり、該コラムシャフトは、内輪の円筒凹部に嵌合固定された円筒ブッシュの内周面と、合成樹脂製スリーブの円筒部外周面とで形成される合成樹脂同士の摩擦係数の低い摺動面を介して支承されるため、低摩擦での円滑なステアリング操作を可能とする。また、支持脚が内輪の円筒凹部に対応しない外周面と該外周面に対応する外輪の内周面とに一体的に連結されているため、内輪の円筒凹部には軸受をハウジングに圧入固定する際の圧入力が直接作用しないので、該円筒凹部に嵌合固定される円筒ブッシュの内径寸法精度（真円度）に影響が及ぼされない。さらに、溶接加工による溶接ひずみがハウジングの内径寸法精度（真円度）に悪影響をもたらした場合でも、ハウジングの内径寸法精度（真円度）の狂いは、内輪の円筒凹部に直接作用しないので、該円筒凹部に嵌合固定される円筒ブッシュの内径寸法に影響が及ぼされない。
【００１２】
本発明の第二の態様のステアリングコラム用軸受では、第一の態様のステアリングコラム用軸受において、円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に形成された金属焼結層と該金属焼結層に含浸被覆された合成樹脂層との三層構造からなり、該合成樹脂層を内側にして円筒状に捲回して形成される巻きブッシュからなる。金属焼結層に含浸被覆される合成樹脂としては、鉛などの金属粉を充填したポリテトラフルオロエチレン樹脂、潤滑油剤を含有したポリアセタール樹脂などを好ましいものとして提示し得る。
【００１３】
第二の態様のステアリングコラム用軸受によれば、円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に形成された金属焼結層と該金属焼結層に含浸被覆された合成樹脂層との三層構造からなるため、耐圧強度が高められており、予め内径を寸法精度良く形成しておくことにより、軸受をハウジングに圧入固定する際の圧入力が直接作用しないようにする上記の構成に加えて、円筒ブッシュの内径寸法を精度良く保つことができる。
【００１４】
本発明の第三の態様のステアリングコラム用軸受では、第一の態様のステアリングコラム用軸受において、円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に被着形成された合成樹脂滑り層とからなり、該合成樹脂滑り層を内側にして円筒状に捲回して形成される巻きブッシュからなる。
【００１５】
第三の態様のステアリングコラム用軸受によれば、円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に被着形成された合成樹脂滑り層とからなるため、第二の態様のステアリングコラム用軸受のそれと同様に、耐圧強度が高められており、予め内径を寸法精度良く形成しておくことにより、軸受をハウジングに圧入固定する際の圧入力が直接作用しないようにする上記の構成に加えて、円筒ブッシュの内径寸法を精度良く保つことができる。尚、斯かる円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に被着形成された合成樹脂滑り層とからなる条片を、該合成樹脂滑り層を内側にして円筒状に捲回して形成される巻きブッシュからなっていてもよい。合成樹脂滑り層の合成樹脂としては、第二の態様のステアリングコラム用軸受における合成樹脂層に用いられるものと同様の合成樹脂を好ましいものとして提示し得る。
【００１６】
本発明の第四の態様のステアリングコラム用軸受では、第一から第三のいずれかの態様のステアリングコラム用軸受において、合成樹脂製スリーブの縮径部は、円筒部の内周面に軸方向に互いに所定間隔隔てて形成された少なくとも二つの環状突条部からなり、本発明の第五の態様のステアリングコラム用軸受では、第一から第三の態様のステアリングコラム用軸受において、合成樹脂製スリーブの縮径部は、円筒部の内周面に軸方向に沿いかつ円周方向に複数個形成された突条部からなる。第四及び第五の態様における縮径部の内径は、好ましくは、円筒部の内周面の内径よりも０．５〜１．０ｍｍ程度小さく形成される。
【００１７】
第四及び第五の態様のステアリングコラム用軸受の夫々によれば、縮径部が二つの環状突条部又は軸方向の複数個の突条部からなるために、コラムシャフトの把持を更に良好に行い得、而して、低摩擦での円滑なステアリング操作を可能とする上記の効果をより確実に得ることができる。
【００１８】
本発明の第六の態様のステアリングコラム用軸受では、第一から第五のいずれかの態様のステアリングコラム用軸受において、合成樹脂製スリーブには、円筒部の端部から環状鍔部にかけてスリットが形成されており、本発明の第七の態様のステアリングコラム用軸受では、第一から第五のいずれかの態様のステアリングコラム用軸受において、合成樹脂製スリーブには、円筒部の端部から環状鍔部の近傍にかけて延びる少なくとも三つの切割り溝が円周方向に等間隔に形成されている。
【００１９】
第六及び第七の態様のステアリングコラム用軸受によれば、スリット又は切割り溝により合成樹脂製スリーブを縮径できるため、合成樹脂製スリーブの円筒部の外周面を、該円筒凹部に嵌合固定された円筒ブッシュの内周面に摺動自在に接触させ、該環状鍔部を内輪のリップ部と該円筒凹部に嵌合固定された円筒ブッシュの端面との間に挿入することからなる合成樹脂製スリーブの内輪内への装着を容易に行うことができる。
【００２０】
本発明の第八の態様のステアリングコラム用軸受では、第一から第七のいずれかの態様のステアリングコラム用軸受において、合成樹脂製スリーブの円筒部の外周面には、軸方向に互いに所定間隔隔てて少なくとも二つの環状溝が形成されている。
【００２１】
第八の態様のステアリングコラム用軸受によれば、二つの環状溝をグリースなどの潤滑剤の溜り部とできる結果、摺動面となる合成樹脂製スリーブの円筒部の外周面と円筒ブッシュの内周面とで形成される合成樹脂同士の摺動面には、常に潤滑剤による湿潤性が与えられるので、ステアリング操作をより円滑に行わせることができる。
【００２２】
本発明の第九の態様のステアリングコラム用軸受装置は、弾性を有する合成樹脂製のアウターブッシュとインナーブッシュと合成樹脂製スリーブとからなる軸受を具備しており、ここで、アウターブッシュは、円筒内周面の一方の端部近傍に円周方向に沿い、かつ径方向に突設されたリップ部及び該リップ部と軸方向に所定間隔隔てて円周方向に沿って突設され、該リップ部及び円筒内周面と協同して円筒凹部を画定する係止突条部を具備した内輪と、外周面に軸方向に沿う突条部を円周方向に複数個具備した外輪と、円周方向に延びる外縁では内輪の円筒凹部に対応しない外周面に、円周方向に延びる内縁では当該外周面に対応する外輪の内周面に夫々一体的に連結された支持脚と、該内輪のリップ部に対応する外周面から軸方向に沿って支持脚まで延び、内輪の外周面、外輪の内周面及び支持脚の夫々に一体的に連結された少なくとも三本の補強リブとを具備し、インナーブッシュは、内輪の円筒凹部に挿入保持され、少なくとも内周面が合成樹脂で形成された円筒ブッシュからなり、合成樹脂製スリーブは、円筒部と、該円筒部の一方の端部に設けられた環状鍔部と、該円筒部の内周面に設けられていると共に、該内周面の内径よりも小さい内径の縮径部とを具備しており、該合成樹脂製スリーブは、該円筒部の外周面を該円筒ブッシュの内周面に摺動自在に接触させて、該環状鍔部を前記内輪のリップ部と該円筒凹部に挿入保持された円筒ブッシュの端面との間に挿入させて内輪内に配されており、該軸受は、外輪の外周面の突条部においてハウジング内に圧入され、コラムシャフトは、インナーブッシュの合成樹脂製スリーブの縮径部に締代をもって挿入されていると共に、円筒ブッシュの内周面と合成樹脂製スリーブの円筒部の外周面とで形成される合成樹脂同士の摺動面を介して支承されていることを特徴とする。
【００２３】
第九の態様のステアリングコラム用軸受装置によれば、外径が該合成樹脂製スリーブの縮径部の内径よりも大きく形成されたコラムシャフトが該合成樹脂製スリーブの縮径部に締代をもって把持されているので、該コラムシャフトと合成樹脂製スリーブとは、ステアリング操作時に共に回転することになり、而して、該コラムシャフトは、内輪の円筒凹部に嵌合固定される円筒ブッシュの内周面と合成樹脂製スリーブの該円筒部外周面とで形成される合成樹脂同士の摩擦係数の低い摺動面を介して支承される結果、低摩擦での円滑なステアリング操作が可能となる。また、支持脚が内輪の円筒凹部に対応しない外周面と該外周面に対応する外輪の内周面とに一体的に連結されているため、内輪の円筒凹部には軸受をハウジングに圧入固定する際の圧入力が直接作用しないので、該円筒凹部に嵌合固定される円筒ブッシュの内径寸法精度（真円度）に影響が及ぼされない。さらに、溶接加工による溶接ひずみの影響がハウジングの内径寸法精度に悪影響をもたらした場合でも、ハウジングの内径寸法精度の狂いは内輪の円筒凹部に直接作用しないので、該円筒凹部に嵌合固定される円筒ブッシュの内径寸法精度に影響が及ぼされない。
【００２４】
本発明の第十の態様のステアリングコラム用軸受装置では、第九の態様のステアリングコラム用軸受装置において、円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に形成された金属焼結層と該金属焼結層に含浸被覆された合成樹脂層との三層構造からなり、該合成樹脂層を内側にして円筒状に捲回して形成される巻きブッシュからなる。
【００２５】
第十の態様のステアリングコラム用軸受装置によれば、円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に形成された金属焼結層と該金属焼結層に含浸被覆された合成樹脂層との三層構造からなるため、耐圧強度が高められており、予め内径寸法精度を精度良く形成しておくことにより、軸受をハウジングに圧入固定する際の圧入力が直接作用しないようにする上記構成に加えて、円筒ブッシュの内径寸法精度を精度良く保つことができる。
【００２６】
本発明の第十一の態様のステアリングコラム用軸受装置では、第九の態様のステアリングコラム用軸受装置において、円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に被着形成された合成樹脂滑り層とからなり、該合成樹脂滑り層を内側にして円筒状に捲回して形成される巻きブッシュからなる。
【００２７】
第十一の態様のステアリングコラム用軸受装置によれば、円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に被着形成された合成樹脂滑り層とからなるため、第十の態様のステアリングコラム用軸受装置のそれと同様に、耐圧強度が高められており、予め内径を寸法精度良く形成しておくことにより、軸受をハウジングに圧入固定する際の圧入力が直接作用しないようにする上記の構成に加えて、円筒ブッシュの内径寸法を精度良く保つことができる。尚、斯かる円筒ブッシュは、薄鋼鈑と該薄鋼鈑の表面に一体に被着形成された合成樹脂滑り層とからなる条片を、該合成樹脂滑り層を内側にして円筒状に捲回して形成される巻きブッシュからなっていてもよい。
【００２８】
本発明の第十二の態様のステアリングコラム用軸受装置では、第九から第十一のいずれかの態様のステアリングコラム用軸受装置において、合成樹脂製スリーブの縮径部は、円筒部の内周面に軸方向に互いに所定間隔隔てて形成された少なくとも二つの環状突条部からなり、また本発明の第十三の態様のステアリングコラム用軸受装置では、第九から第十一のいずれかの態様のステアリングコラム用軸受装置において、合成樹脂製スリーブの縮径部は、円筒部の内周面に軸方向に沿いかつ円周方向に複数個形成された突条部からなる。
【００２９】
第十二び第十三の態様のステアリングコラム用軸受装置の夫々によれば、縮径部が二つの環状突条部又は軸方向の複数個の突条部からなるために、コラムシャフトの把持を更に良好に行い得、而して、低摩擦での円滑なステアリング操作を可能とする上記の効果をより確実に得ることができる
【００３０】
本発明の第十四の態様のステアリングコラム用軸受装置では、第九から第十三のいずれかの態様のステアリングコラム用軸受装置において、合成樹脂製スリーブには、円筒部の端部から環状鍔部にかけてスリットが形成されており、また本発明の第十五の態様のステアリングコラム用軸受装置では、第九から第十三のいずれかの態様のステアリングコラム用軸受装置において、合成樹脂製スリーブには、円筒部の端部から環状鍔部近傍にかけて延びる少なくとも三つの切割り溝が円周方向に等間隔に形成されている。
【００３１】
第十四及び第十五の態様のステアリングコラム用軸受装置の夫々によれば、スリット又は切割り溝により合成樹脂製スリーブを縮径できるため、合成樹脂製スリーブの円筒部の外周面を、該円筒凹部に嵌合固定された円筒ブッシュの内周面に摺動自在に接触させ、該環状鍔部を内輪のリップ部と該円筒凹部に嵌合固定された円筒ブッシュの端面との間に挿入することからなる合成樹脂製スリーブの内輪内への装着を容易に行うことができる。
【００３２】
本発明の第十六の態様のステアリングコラム用軸受装置では、第九から第十五のいずれかの態様のステアリングコラム用軸受装置において、合成樹脂製スリーブの円筒部の外周面には、軸方向に互いに所定間隔隔てて少なくとも二つの環状溝が形成されている。
【００３３】
第十六の態様のステアリングコラム用軸受装置によれば、円筒部の外周面に軸方向に所定間隔隔てて形成された少なくとも二つの環状溝は、グリースなどの潤滑剤の溜り部となり、摺動面となる合成樹脂製スリーブの円筒部外周面と円筒ブッシュの内周面とで形成される合成樹脂同士の摺動面は、常に潤滑剤による湿潤性が与えられるので、ステアリング操作をより円滑に行わせることができる。
【００３４】
以下、本発明及びその実施の形態を、図面に示す好ましい例に基づいて説明する。なお、本発明はこれらの例に何等限定されないのである。
【００３５】
【発明の実施の形態】
図１から図４において、本例のステアリングコラム用軸受装置２０は、弾性を有する合成樹脂で形成されたアウターブッシュ２１、アウターブッシュ２１内に挿入保持されるインナーブッシュ２２及び合成樹脂製スリーブ２３からなる軸受２４と、軸受２４が圧入固定されるパイプ状のハウジング２５と、円筒ブッシュからなるインナーブッシュ２２に支承されるコラムシャフト２６とを具備している。
【００３６】
アウターブッシュ２１は、円筒内周面２７の一方の端部近傍に円周方向に沿い、かつ径方向に突設された複数個（本例では６個）のリップ部２８及びリップ部２８から軸方向に所定間隔隔てて円周方向に沿って突設され、リップ部２８及び円筒内周面２７と協同して円筒凹部２９を画定する複数個（本例では６個）の係止突条部３０を具備した内輪３１と、外周面に軸方向に沿いかつ円周方向にわたって形成された複数個の突条部３２及び一方の端部に径方向外方に延設された環状鍔部３３を具備した外輪３４と、円周方向に伸びる外縁では内輪３１の円筒凹部２９に対応しない外周面に、円周方向に伸びる内縁では該外周面に対応する外輪３４の内周面に夫々一体的に連結された環状の支持脚３５と、内輪３１のリップ部２８に対応する外周面から支持脚３５まで延び、内輪３１の外周面、外輪３４の内周面及び支持脚３５の夫々に一体的に連結された三本の補強リブ３６とからなっている。
【００３７】
アウターブッシュ２１において、外輪３４の一方の端部に一体に形成された環状鍔部３３は、軸受２４を後述するハウジング２５へ圧入固定する際に、当該軸受２４をハウジング２５の端部に固定する場合において必要とされるもので、軸受２４をハウジング２５内の任意の位置に圧入固定する場合には必要としない。
【００３８】
補強リブ３６は、円筒凹部２９を補強するものであり、本例では円周方向に均等に配置、好ましくは径方向において相対応しないように配置できれば必ずしも三本に限定されない。補強リブ３６を円周方向に均等に配置、好ましくは径方向に相対応しないように配置するのは、軸受２４をハウジング２５に圧入固定する際の圧入力の影響を、円筒凹部２９に挿入保持されるインナーブッシュ２２の内径寸法精度に及ぼさないようにするためである。
【００３９】
円筒ブッシュからなるインナーブッシュ２２は、薄鋼鈑と、この薄鋼鈑の表面に一体に接合された焼結金属層と、この焼結金属層に含浸被覆された合成樹脂層との三層構造からなる条片を、合成樹脂層を内側にして円筒状に捲回して形成した、所謂巻きブッシュからなる。インナーブッシュ２２は、アウターブッシュ２１の内輪３１の円筒凹部２９に挿入保持される。尚、インナーブッシュ２２は、三層構造からなるものに代えて、薄鋼鈑と該薄鋼鈑の表面に一体に被着形成された合成樹脂滑り層とからなる条片を、該合成樹脂滑り層を内側にして円筒状に捲回して形成される巻きブッシュからなっていてもよい。
【００４０】
合成樹脂製スリーブ２３は、円筒部３８と、円筒部３８の一方の端部に一体的に形成された環状凸部３９と、円筒部３８の他方の端部に一体的に形成された環状鍔部４０とを具備しており、該円筒部３８の外周面には、環状凸部３９と環状鍔部４０と円筒部３８の外周面とで環状凹部４１が形成されている。円筒部３８の内周面４２には、軸方向に所定の間隔を隔てて該内周面４２の内径よりも小さい内径を有する二つの環状凸条部４３、４３が一体的に形成されており、これら環状凸条部４３、４３によって円筒部３８の内周面４２に縮径部４４が形成されている。合成樹脂製スリーブ２３には、円筒部３８の一方の端部の環状凸部３９から他方の環状鍔部４０まで伸びた一つのスリット４５が形成されている。
【００４１】
合成樹脂製スリーブ２３の円筒部３８の外周面には、軸方向に所定の間隔を隔てて二つの環状凹部４６、４６が形成されており、該環状凹部４６はグリースなどの潤滑油剤の溜り部となる。円筒部３８の内周面４２に形成された縮径部４４の環状凸条部４３、４３と対応する円筒部３８の外周面に環状凹部４６を形成することにより、合成樹脂製スリーブ２３の肉厚をほぼ均一とすることができ、肉厚不同に起因するひけや変形の発生を防止することができる。
【００４２】
合成樹脂製スリーブ２３は、円筒部３８の外周面の環状凹部４１の底面、すなわち円筒部３８の外周面を、アウターブッシュ２１の内輪３１の円筒凹部２９に挿入保持されたインナーブッシュ２２の内周面に摺動自在に接触させ、環状鍔部４０を、内輪３１のリップ部２８と円筒凹部２９に挿入保持されたインナーブッシュ２２の端面との間に摺動自在に挿入し、環状凸部３９を内輪３１の係止突条部３０に摺動自在に接触させて、内輪３１内に配されている。尚、内輪３１の係止突条部３０の位置に、係止突条部３０に代えてリップ部２８を設け、内輪３１のリップ部２８の位置に、リップ部２８に代えて係止突条部３０を設けてもよく、環状鍔部４０を、斯かる内輪３１のリップ部２８と円筒凹部２９に挿入保持されたインナーブッシュ２２の端面との間に摺動自在に挿入して、合成樹脂製スリーブ２３を内輪３１内に配してもよく、更に、環状凸部３９を省いて合成樹脂製スリーブ２３を形成してもよい。
【００４３】
以上のステアリングコラム装置２０では、コラムシャフト２６は、合成樹脂製スリーブ２３の円筒部３８の内周面４２に形成された縮径部４４に締代をもって挿入されることになり、コラムシャフト２６は、内輪３１の円筒凹部２９に挿入保持されたインナーブッシュ２２の内周面と合成樹脂製スリーブ２３の円筒部３８の外周面とで形成される合成樹脂同士の摩擦係数の低い摺動面を介して支承されるため、低摩擦での円滑なステアリング操作を可能とする。
【００４４】
また、内輪３１の円筒凹部２９に対応しない外周面と該外周面に対応する外輪３４の内周面とがその円周方向において支持脚３５によって一体的に連結されているため、内輪３１の円筒凹部２９には、軸受２４をハウジング２５に圧入固定する際の圧入力が直接作用しないので、円筒凹部２９に嵌合固定されるインナーブッシュ２２の内径寸法精度（真円度）に影響が及ぼされない。さらに、溶接加工による溶接ひずみの影響がハウジング２５の内径寸法精度に悪影響をもたらした場合でも、ハウジング２５の内径寸法精度の狂いは、内輪３１の円筒凹部２９に直接作用しないので、円筒凹部２９に挿入保持されるインナーブッシュ２２の内径寸法精度に影響が及ぼされない。
【００４５】
図４及び図５に示す他の態様の合成樹脂製スリーブ２３は、円筒部３８と、円筒部３８の一方の端部に形成された環状鍔部４０とを具備しており、円筒部３８の内周面４２には、軸方向に沿いかつ円周方向に複数個形成された突条部４７からなる縮径部４４が形成されている。突条部４７で形成される内径は、内周面４２の内径よりも小さい内径を有している。また、図４及び図５に示す合成樹脂製スリーブ２３には、円筒部３８の一方の端部に形成された環状鍔部４０と反対側の端部から該環状鍔部４０の近傍にかけて延びる少なくとも三つの切割り溝４８が円周方向に等間隔に形成されている。
【００４６】
更に図４及び図５に示す合成樹脂製スリーブ２３の円筒部３８の外周面には、軸方向に所定の間隔を隔てて二つの環状凹部４６、４６が形成されており、環状凹部４６はグリースなどの潤滑油剤の溜り部となる。
【００４７】
図４及び図５に示す合成樹脂製スリーブ２３は、図１から図４に示す合成樹脂製スリーブ２３と同様、円筒部３８の外周面をインナーブッシュ２２の内周面に摺動自在に接触させ、環状鍔部４０を内輪３１のリップ部２８と該円筒凹部２９に挿入保持されたインナーブッシュ２２の端面との間に挿入して配される。
【００４８】
斯かる図４及び図５の合成樹脂製スリーブ２３でも、前記と同様の効果を得ることができる。
【００４９】
尚、前記の例では、リップ部２８及び係止突条部３０を円周方向に分割して内輪３１に設けたが、円周方向に分割にすることなしに、リップ部２８及び係止突条部３０のうちの少なくとも一方を円周方向に連続して全周に亘って内輪３１に設けてもよい。
【００５０】
【発明の効果】
本発明によれば、合成樹脂製スリーブの円筒部の内周面に形成された縮径部に締代をもって挿入されるコラムシャフトは、内輪の円筒凹部に挿入保持された円筒ブッシュの内周面と合成樹脂製スリーブの円筒部外周面とで形成される合成樹脂同士の摩擦係数の低い摺動面を介して支承されるため、低摩擦での円滑なステアリング操作を可能とするステアリングコラム用軸受装置を提供することができる。
【００５１】
また、本発明によれば、インナーブッシュの摺動部位の内径寸法精度に影響を及ぼすことがなく、コラムシャフトを円滑に支承し、ステアリング操作をよりスムースに行わせることができるステアリングコラム用軸受及びこの軸受を用いた軸受装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の好ましい一実施例の断面図である。
【図２】図１に示す実施例の左側面図である。
【図３】図１に示す実施例の右側面図である。
【図４】合成樹脂製スリーブの正面図である。
【図５】合成樹脂製スリーブの他の態様の断面図である。
【図６】図５に示す他の態様の左側面図である。
【図７】先行技術を示す断面図である。
【図８】図７のＶＩＩＩ−ＶＩＩＩ線断面図である。
【符号の説明】
２０ステアリングコラム用軸受装置
２１アウターブッシュ
２２インナーブッシュ
２３合成樹脂製スリーブ
２４軸受
２５ハウジング
２６コラムシャフト
３１内輪
３４外輪
３５支持脚
３６補強リブ
４４縮径部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steering column bearing for supporting a steering column shaft of an automobile and a bearing device using the bearing.
[0002]
[Prior art]
Conventionally, a sliding bearing made of a ball bearing or a synthetic resin has been used as a steering column bearing for supporting a steering column shaft of an automobile. Generally, for bearings that support automobile steering column shafts, rotation conditions such as load and speed are not so severe, but vibration absorption and friction torque stability that absorbs vibrations acting on the column shaft during idling and the like are stable. Sex is required. In ball bearings, although the friction torque is stable, it is inferior in vibration absorption, and it is necessary to finish the dimensional accuracy of the housing that fixes the ball bearing and the column shaft supported by the ball bearing with high accuracy. In addition to being expensive, there is a problem that the processing cost is increased.
[0003]
The sliding bearing made of synthetic resin has the advantages of lower cost and better vibration absorption than the above ball bearings, but requires an appropriate clearance (bearing gap) between the sliding bearing and the column shaft. Further, there is a problem that a collision sound is generated between the shaft and the bearing due to the vibration generated in the column shaft, and is transmitted as an unpleasant sound to a person driving the automobile. If the clearance is reduced to suppress the occurrence of the collision noise, a stick crus phenomenon occurs, which causes a problem that the stability of the friction torque is hindered.
[0004]
In view of the above, the applicant of the present application previously described in Japanese Patent Application No. 4-54411 (Registration No. 2576820: hereinafter referred to as “prior art”) bearings acting on the column shaft during steering operation (when the steering wheel is rotated). A steering column bearing device has been proposed which can be smoothly supported and can absorb vibrations acting on the shaft when no load is applied to the column shaft, such as when idling.
[0005]
This prior art will be described with reference to FIGS. A steering column bearing device 1 includes a bearing 4 including an outer bush 2 made of a rubber elastic body or an elastic synthetic resin, and an inner bush 3 inserted into the inner surface of the outer bush 2, and a housing for press-fitting and fixing the bearing 4. 5 and a column shaft 6 supported by the bearing 4. The outer bush 2 has an outer ring 12 provided with a plurality of ridges 11 formed on the outer peripheral surface along the axial direction of the bush and over the entire circumference, and an inner surface of the outer ring 12 in the axial direction of the outer ring 12. And an inner ring 14 integrally connected by a plurality of extended support legs 13. The inner ring 14 protrudes from one end portion of the inner surface 15 radially inward with an inner diameter slightly smaller than the inner diameter of the inner bush 3 and is formed over the circumferential direction, and is continuous with the annular lip portion 16. The diameter-enlarging cylindrical portion 17 and the annular lip portion 16 and the diameter-enlarging cylindrical portion 17 that is spaced apart from the annular lip portion 16 in the circumferential direction by a part or the entire circumference have an inner diameter larger than the inner diameter of the inner bush 3 and smaller than the outer diameter. And a stop ridge portion 18. The inner bush 3 is inserted and held in the enlarged diameter cylindrical portion 17 between the annular lip portion 16 and the locking protrusion 18 on the inner surface of the inner ring 14 of the outer bush 2, and the outer bush holding the inner bush 3. 2 is press-fitted and fixed in the housing 5 at the ridge portion 11 on the outer peripheral surface of the outer ring 12, and the column shaft 6 is in sliding contact with the annular lip portion 16 on the inner surface of the inner ring 14 of the outer bush 2 with a tightening margin. The inner circumferential surface 3 is supported with a predetermined clearance (bearing gap).
[0006]
[Problems to be solved by the invention]
The above-described steering column bearing device 1 of the prior art solves the problems of the prior art described above, and smoothly supports the load acting on the column shaft 6 by the bearing 4 during steering operation. In a state where no load is applied to 6, vibration acting on the column shaft 6 can be absorbed. However, when the bearing 4 is firmly press-fitted with respect to the housing 5 for the purpose of preventing the shaft 5 from coming off and rotating in the circumferential direction, the bearing 4 is press-fitted on the outer peripheral surface of the outer ring 12. Since the outer ring 12 and the inner ring 14 are connected by a plurality of support legs 13 extending in the axial direction, the pressure input is between the outer peripheral surface of the corresponding outer ring 12 of the support leg 13 and the support leg 13. Unlike the outer peripheral surface of the outer ring 12 corresponding to the portion, the pressure input does not act evenly on the inner bush 3 held by the enlarged diameter cylindrical portion 17 of the inner ring 14 that supports the column shaft 6, and the inner diameter of the inner bush 3 There is a problem of adversely affecting the dimensional accuracy (roundness).
[0007]
In addition, when a member (bracket) for fixing the housing 5 to the vehicle body side is attached to the outer peripheral surface of the housing 5 by welding, the welding distortion caused by the welding adversely affects the inner diameter dimensional accuracy (roundness) of the housing 5. As a result, the dimensional accuracy (roundness) of the inner bush 3 of the bearing 4 fixed to the housing 5 is further deteriorated. The quality of the inner dimensional accuracy (roundness) of the inner bush 3 of the bearing 4 affects the smooth sliding between the inner bush 3 and the column shaft 6 supported by the inner bush 3, and the deterioration thereof is affected by the smoothness. This is a problem that must be avoided as much as possible.
[0008]
The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to smoothly support the column shaft without affecting the accuracy of the inner diameter of the sliding portion of the inner bush, and to steer. An object of the present invention is to provide a steering column bearing that can be operated more smoothly and a bearing device using the bearing.
[0009]
[Means for Solving the Problems]
The steering column bearing according to the first aspect of the present invention comprises an elastic synthetic resin outer bush, an inner bush, and a synthetic resin sleeve, wherein the outer bush is one end of a cylindrical inner peripheral surface. A lip portion extending in the circumferential direction in the vicinity of the portion and projecting in the radial direction, and projecting along the circumferential direction at a predetermined interval in the axial direction from the lip portion, the lip portion and the cylindrical inner peripheral surface; An inner ring having a locking ridge that cooperates to define a cylindrical recess, an outer ring having a plurality of ridges in the circumferential direction along the axial direction on the outer circumferential surface, and an inner ring at the outer edge extending in the circumferential direction. From the outer peripheral surface corresponding to the outer peripheral surface corresponding to the outer peripheral surface of the outer ring corresponding to the outer peripheral surface corresponding to the outer peripheral surface and the outer peripheral surface corresponding to the outer peripheral surface corresponding to the outer peripheral surface to the outer peripheral surface corresponding to the outer peripheral surface. Along the axial direction to the support leg, At least three reinforcing ribs integrally connected to the peripheral surface, the inner peripheral surface of the outer ring and the support leg, and the inner bush is inserted and held in the cylindrical recess of the inner ring, and at least the inner peripheral surface Consists of a cylindrical bush formed of synthetic resin, and the synthetic resin sleeve is provided on the cylindrical portion, an annular flange provided at one end of the cylindrical portion, and an inner peripheral surface of the cylindrical portion. The synthetic resin sleeve is slidable on the inner peripheral surface of the cylindrical bushing with the outer peripheral surface of the cylindrical portion. The annular flange is placed between the lip portion of the inner ring and the end face of the cylindrical bush inserted and held in the cylindrical recess, and is arranged in the inner ring.
[0010]
As the synthetic resin having elasticity that forms the outer bush, it is flexible and tough, and generally has a Shore hardness (D type) of 40 to 60 and a rebound resilience value (JIS-K6301) of 50 to 80. The rubber-like elastic behavior remains, and for example, a polyester / ether copolymer or polyurethane can be presented as a preferable one. Moreover, as a synthetic resin which forms a sleeve, a polyacetal resin, a polyamide resin, a polyolefin resin, etc. can be shown as a preferable thing.
[0011]
According to the steering column bearing of the first aspect, the column shaft is inserted into the reduced diameter portion formed on the inner peripheral surface of the cylindrical portion of the synthetic resin sleeve with a tightening margin. And is supported via a sliding surface having a low friction coefficient between synthetic resins formed by the inner peripheral surface of the cylindrical bush fitted and fixed to the cylindrical recess of the inner ring and the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve. Therefore, a smooth steering operation with low friction is possible. Further, since the support leg is integrally connected to the outer peripheral surface not corresponding to the cylindrical recess of the inner ring and the inner peripheral surface of the outer ring corresponding to the outer peripheral surface, the bearing is press-fitted and fixed to the cylindrical recess of the inner ring. Since the pressure input at the time does not act directly, the inner diameter dimensional accuracy (roundness) of the cylindrical bush fitted and fixed to the cylindrical recess is not affected. Furthermore, even if the welding distortion caused by welding has an adverse effect on the inner diameter dimensional accuracy (roundness) of the housing, the deviation in the inner diameter dimensional accuracy (roundness) of the housing does not directly affect the cylindrical recess of the inner ring. The inner diameter of the cylindrical bush fitted and fixed to the cylindrical recess is not affected.
[0012]
In the steering column bearing of the second aspect of the present invention, in the steering column bearing of the first aspect, the cylindrical bush includes a thin steel plate and a sintered metal layer integrally formed on the surface of the thin steel plate. It consists of a three-layer structure with a synthetic resin layer impregnated and coated on the sintered metal layer, and a wound bush formed by winding the synthetic resin layer in a cylindrical shape. As the synthetic resin impregnated and coated on the metal sintered layer, a polytetrafluoroethylene resin filled with metal powder such as lead, a polyacetal resin containing a lubricant, and the like can be presented as preferable ones.
[0013]
According to the steering column bearing of the second aspect, the cylindrical bush includes a thin steel plate, a metal sintered layer integrally formed on the surface of the thin steel plate, and a synthetic resin impregnated and coated on the metal sintered layer. Since it has a three-layer structure with layers, the pressure resistance is increased, and the pressure input when the bearing is press-fitted and fixed to the housing is prevented from acting directly by forming the inner diameter in advance with dimensional accuracy. In addition to the configuration described above, the inner diameter of the cylindrical bush can be accurately maintained.
[0014]
In the steering column bearing according to the third aspect of the present invention, in the steering column bearing according to the first aspect, the cylindrical bush is formed of a thin steel plate and a synthetic resin slide integrally formed on the surface of the thin steel plate. And a wound bush formed by winding in a cylindrical shape with the synthetic resin sliding layer inside.
[0015]
According to the steering column bearing of the third aspect, the cylindrical bush is composed of the thin steel plate and the synthetic resin sliding layer integrally formed on the surface of the thin steel plate. Similar to that of column bearings, the pressure resistance is increased, and the above configuration prevents the pressure input when the bearing is press-fitted and fixed directly into the housing by forming the inner diameter with high dimensional accuracy in advance. In addition, the inner diameter of the cylindrical bush can be maintained with high accuracy. In addition, such a cylindrical bush has a strip formed of a thin steel plate and a synthetic resin sliding layer integrally formed on the surface of the thin steel plate, and is formed into a cylindrical shape with the synthetic resin sliding layer inside. You may consist of the winding bush formed by rotation. As the synthetic resin of the synthetic resin sliding layer, the same synthetic resin as that used for the synthetic resin layer in the steering column bearing of the second aspect can be presented as a preferable one.
[0016]
In the steering column bearing according to the fourth aspect of the present invention, in the steering column bearing according to any one of the first to third aspects, the reduced diameter portion of the synthetic resin sleeve is axially formed on the inner peripheral surface of the cylindrical portion. In the steering column bearing according to the fifth aspect of the present invention, the steering column bearing according to the first to third aspects is made of a synthetic resin. The reduced diameter portion of the sleeve is composed of a plurality of protrusions formed along the axial direction and in the circumferential direction on the inner peripheral surface of the cylindrical portion. The inner diameter of the reduced diameter portion in the fourth and fifth aspects is preferably smaller by about 0.5 to 1.0 mm than the inner diameter of the inner peripheral surface of the cylindrical portion.
[0017]
According to each of the steering column bearings of the fourth and fifth aspects, the reduced diameter portion is composed of two annular ridge portions or a plurality of axial ridge portions, so that the column shaft can be gripped better. Thus, the above-described effect that enables a smooth steering operation with low friction can be obtained more reliably.
[0018]
In the steering column bearing according to the sixth aspect of the present invention, in the steering column bearing according to any one of the first to fifth aspects, the synthetic resin sleeve has a slit from the end of the cylindrical portion to the annular flange. In the steering column bearing according to the seventh aspect of the present invention, in the steering column bearing according to any one of the first to fifth aspects, the synthetic resin sleeve has an annular shape from the end of the cylindrical portion. At least three slits extending in the vicinity of the flange are formed at equal intervals in the circumferential direction.
[0019]
According to the steering column bearings of the sixth and seventh aspects, the diameter of the synthetic resin sleeve can be reduced by the slit or the slit groove, so the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve is fitted into the cylindrical recess. Combining the inner peripheral surface of the fixed cylindrical bush slidably, and inserting the annular flange between the lip portion of the inner ring and the end surface of the cylindrical bush fitted and fixed to the cylindrical recess. The resin sleeve can be easily mounted in the inner ring.
[0020]
In the steering column bearing according to the eighth aspect of the present invention, in the steering column bearing according to any one of the first to seventh aspects, the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve is axially spaced by a predetermined distance from each other. At least two annular grooves are formed apart from each other.
[0021]
According to the steering column bearing of the eighth aspect, the two annular grooves can be used as a reservoir for a lubricant such as grease. As a result, the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve, which becomes the sliding surface, and the cylindrical bush Since the sliding surface between the synthetic resins formed with the peripheral surface is always given wettability by the lubricant, the steering operation can be performed more smoothly.
[0022]
A steering column bearing device according to a ninth aspect of the present invention includes a bearing comprising an elastic synthetic resin outer bush, an inner bush, and a synthetic resin sleeve, wherein the outer bush is a cylinder. A lip portion extending in the circumferential direction in the vicinity of one end of the inner peripheral surface and projecting in the radial direction, and projecting along the circumferential direction at a predetermined interval in the axial direction from the lip portion. An inner ring provided with a locking ridge part that defines a cylindrical recess in cooperation with the inner part and the cylindrical inner peripheral surface, an outer ring provided with a plurality of ridge parts along the axial direction on the outer peripheral surface, and a circumference A support leg integrally connected to the outer peripheral surface that does not correspond to the cylindrical recess of the inner ring at the outer edge extending in the direction and the inner peripheral surface of the outer ring corresponding to the outer peripheral surface at the inner edge extending in the circumferential direction, and a lip of the inner ring Along the axial direction from the outer peripheral surface corresponding to the part The inner bush is inserted and held in the cylindrical recess of the inner ring, extending to the holding leg and having at least three reinforcing ribs integrally connected to the outer peripheral surface of the inner ring, the inner peripheral surface of the outer ring and the support leg. The synthetic resin sleeve comprises a cylindrical bush, an annular flange provided at one end of the cylindrical portion, and an inner periphery of the cylindrical portion. And the synthetic resin sleeve has an outer peripheral surface of the cylindrical portion that is an inner peripheral surface of the cylindrical bush. The annular flange is inserted between the lip portion of the inner ring and the end face of the cylindrical bush inserted and held in the cylindrical recess, and is disposed in the inner ring. The outer ring is press-fitted into the housing at the protrusion on the outer peripheral surface, The shaft is inserted into the reduced diameter portion of the synthetic resin sleeve of the inner bush with a tightening margin, and between the synthetic resins formed by the inner peripheral surface of the cylindrical bush and the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve. It is supported through a sliding surface.
[0023]
According to the steering column bearing device of the ninth aspect, the column shaft having an outer diameter larger than the inner diameter of the reduced diameter portion of the synthetic resin sleeve has a margin for the reduced diameter portion of the synthetic resin sleeve. Since this is held, the column shaft and the synthetic resin sleeve rotate together during the steering operation. Therefore, the column shaft is fitted inside the cylindrical recess of the inner ring and fixed inside the cylindrical bush. As a result of being supported through a sliding surface having a low coefficient of friction between the synthetic resins formed by the peripheral surface and the cylindrical portion outer peripheral surface of the synthetic resin sleeve, a smooth steering operation with low friction becomes possible. Further, since the support leg is integrally connected to the outer peripheral surface not corresponding to the cylindrical recess of the inner ring and the inner peripheral surface of the outer ring corresponding to the outer peripheral surface, the bearing is press-fitted and fixed to the cylindrical recess of the inner ring. Since the pressure input at the time does not act directly, the inner diameter dimensional accuracy (roundness) of the cylindrical bush fitted and fixed to the cylindrical recess is not affected. Further, even when the influence of welding distortion caused by welding processing adversely affects the inner diameter dimensional accuracy of the housing, the deviation in the inner diameter dimensional accuracy of the housing does not act directly on the cylindrical recess of the inner ring, so that it is fitted and fixed to the cylindrical recess. The internal diameter accuracy of the cylindrical bush is not affected.
[0024]
In the steering column bearing device according to the tenth aspect of the present invention, in the steering column bearing device according to the ninth aspect, the cylindrical bush is formed of a thin steel plate and sintered metal integrally formed on the surface of the thin steel plate. It consists of a three-layer structure of a layer and a synthetic resin layer impregnated and coated on the sintered metal layer, and a wound bush formed by winding the synthetic resin layer in a cylindrical shape.
[0025]
According to the steering column bearing device of the tenth aspect, the cylindrical bush is composed of a thin steel plate, a metal sintered layer integrally formed on the surface of the thin steel plate, and a composite impregnated and coated with the metal sintered layer. Since it has a three-layer structure with a resin layer, the pressure resistance strength is increased, and by accurately forming the inner diameter dimensional accuracy in advance, the pressure input when press-fitting and fixing the bearing to the housing does not act directly In addition to the above configuration, the accuracy of the inner diameter of the cylindrical bush can be maintained with high accuracy.
[0026]
In the steering column bearing device according to the eleventh aspect of the present invention, in the steering column bearing device according to the ninth aspect, the cylindrical bush is integrally formed on the surface of the thin steel plate and the thin steel plate. It consists of a synthetic resin sliding layer, and consists of a wound bush formed by winding the synthetic resin sliding layer inside in a cylindrical shape.
[0027]
According to the steering column bearing device of the eleventh aspect, the cylindrical bush comprises the thin steel plate and the synthetic resin sliding layer integrally formed on the surface of the thin steel plate. As with the steering column bearing device, the pressure resistance is increased, and the inner diameter is previously formed with high dimensional accuracy so that the pressure input when the bearing is press-fitted and fixed to the housing does not act directly. In addition to the above configuration, the inner diameter of the cylindrical bush can be maintained with high accuracy. In addition, such a cylindrical bush has a strip formed of a thin steel plate and a synthetic resin sliding layer integrally formed on the surface of the thin steel plate, and is formed into a cylindrical shape with the synthetic resin sliding layer inside. You may consist of the winding bush formed by rotation.
[0028]
In a steering column bearing device according to a twelfth aspect of the present invention, in the steering column bearing device according to any one of the ninth to eleventh aspects, the reduced diameter portion of the synthetic resin sleeve has an inner periphery of the cylindrical portion. The steering column bearing device according to the thirteenth aspect of the present invention includes any one of the ninth to eleventh aspects. In the steering column bearing device according to the aspect, the reduced diameter portion of the synthetic resin sleeve includes a plurality of protrusions formed along the axial direction and in the circumferential direction on the inner peripheral surface of the cylindrical portion.
[0029]
According to each of the steering column bearing devices of the twelfth and thirteenth aspects, the reduced diameter portion is composed of two annular ridge portions or a plurality of axial ridge portions. Thus, the above-mentioned effect that enables smooth steering operation with low friction can be obtained more reliably.
[0030]
In the steering column bearing device according to the fourteenth aspect of the present invention, in the steering column bearing device according to any one of the ninth to thirteenth aspects, the synthetic resin sleeve has an annular flange from the end of the cylindrical portion. In the steering column bearing device according to the fifteenth aspect of the present invention, in the steering column bearing device according to any one of the ninth to thirteenth aspects, a synthetic resin sleeve is provided. Are formed at equal intervals in the circumferential direction with at least three slits extending from the end of the cylindrical portion to the vicinity of the annular flange.
[0031]
According to each of the steering column bearing devices of the fourteenth and fifteenth aspects, the diameter of the synthetic resin sleeve can be reduced by the slit or the slit groove, so that the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve is The annular bushing is slidably brought into contact with the inner peripheral surface of the cylindrical bush fitted and fixed to the cylindrical recess, and the annular flange is inserted between the lip portion of the inner ring and the end surface of the cylindrical bush fitted and fixed to the cylindrical recess. It is possible to easily mount the synthetic resin sleeve in the inner ring.
[0032]
In the steering column bearing device according to the sixteenth aspect of the present invention, in the steering column bearing device according to any of the ninth to fifteenth aspects, the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve has an axial direction. At least two annular grooves are formed at predetermined intervals.
[0033]
According to the steering column bearing device of the sixteenth aspect, at least two annular grooves formed at predetermined intervals in the axial direction on the outer peripheral surface of the cylindrical portion serve as a reservoir for a lubricant such as grease and slide. The sliding surface of the synthetic resin formed by the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve and the inner peripheral surface of the cylindrical bush is always given wettability by the lubricant, so that the steering operation is smoother Can be done.
[0034]
Hereinafter, the present invention and its embodiments will be described based on preferred examples shown in the drawings. The present invention is not limited to these examples.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
1 to 4, the steering column bearing device 20 of this example includes an outer bush 21 formed of an elastic synthetic resin, an inner bush 22 inserted and held in the outer bush 21, and a synthetic resin sleeve 23. A bearing 24, a pipe-like housing 25 into which the bearing 24 is press-fitted and fixed, and a column shaft 26 supported by an inner bush 22 made of a cylindrical bush.
[0036]
The outer bush 21 is provided with a plurality of (six in this example) lip portions 28 projecting in the radial direction in the vicinity of one end portion of the cylindrical inner peripheral surface 27 and a lip portion 28 from the lip portion 28. A plurality (six in this example) of locking protrusions projecting along the circumferential direction at predetermined intervals in the direction and defining the cylindrical recess 29 in cooperation with the lip portion 28 and the cylindrical inner peripheral surface 27 An inner ring 31 provided with 30, a plurality of protrusions 32 formed on the outer peripheral surface along the axial direction and in the circumferential direction, and an annular flange 33 extending radially outward at one end. The outer ring 34 and the outer edge that extends in the circumferential direction are integrated with the outer peripheral surface that does not correspond to the cylindrical recess 29 of the inner ring 31, and the inner edge that extends in the circumferential direction is integrated with the inner peripheral surface of the outer ring 34 that corresponds to the outer peripheral surface. The connected annular support leg 35 and the outer side corresponding to the lip portion 28 of the inner ring 31 Extending from the surface to the support leg 35, the outer peripheral surface of the inner ring 31, made up of three reinforcing ribs 36. integrally connected to the people each of the inner peripheral surface and the support legs 35 of the outer ring 34.
[0037]
In the outer bush 21, an annular flange 33 formed integrally with one end of the outer ring 34 fixes the bearing 24 to the end of the housing 25 when the bearing 24 is press-fitted and fixed to a housing 25 described later. This is necessary in some cases, and is not necessary when the bearing 24 is press-fitted and fixed at an arbitrary position in the housing 25.
[0038]
The reinforcing ribs 36 reinforce the cylindrical recesses 29, and in this example, the reinforcing ribs 36 are not necessarily limited to three as long as they can be arranged uniformly in the circumferential direction, and preferably arranged so as not to correspond to each other in the radial direction. The reinforcing ribs 36 are arranged evenly in the circumferential direction, preferably arranged so as not to correspond to the radial direction, because the influence of the pressure input when the bearing 24 is press-fitted and fixed to the housing 25 is inserted and held in the cylindrical recess 29. This is to prevent the inner dimensional accuracy of the inner bush 22 from being affected.
[0039]
The inner bush 22 formed of a cylindrical bush has a three-layer structure of a thin steel plate, a sintered metal layer integrally joined to the surface of the thin steel plate, and a synthetic resin layer impregnated and coated on the sintered metal layer. The strip is made of a so-called wound bush formed by winding in a cylindrical shape with the synthetic resin layer inside. The inner bush 22 is inserted and held in the cylindrical recess 29 of the inner ring 31 of the outer bush 21. Note that the inner bush 22 is not made of a three-layer structure, and a strip made of a thin steel plate and a synthetic resin sliding layer integrally formed on the surface of the thin steel plate is replaced with the synthetic resin slide. You may consist of the wound bush formed by winding in a cylinder shape with a layer inside.
[0040]
The synthetic resin sleeve 23 includes a cylindrical portion 38, an annular convex portion 39 integrally formed at one end of the cylindrical portion 38, and an annular flange integrally formed at the other end of the cylindrical portion 38. An annular recess 41 is formed on the outer peripheral surface of the cylindrical portion 38 by the annular convex portion 39, the annular flange 40, and the outer peripheral surface of the cylindrical portion 38. On the inner peripheral surface 42 of the cylindrical portion 38, two annular ridges 43, 43 having an inner diameter smaller than the inner diameter of the inner peripheral surface 42 are integrally formed at a predetermined interval in the axial direction. The reduced diameter portion 44 is formed on the inner peripheral surface 42 of the cylindrical portion 38 by the annular ridge portions 43, 43. The synthetic resin sleeve 23 is formed with one slit 45 extending from the annular convex portion 39 at one end of the cylindrical portion 38 to the other annular flange 40.
[0041]
Two annular recesses 46 are formed on the outer peripheral surface of the cylindrical portion 38 of the synthetic resin sleeve 23 at a predetermined interval in the axial direction. The annular recess 46 is a reservoir for a lubricant such as grease. It becomes. By forming an annular recess 46 on the outer peripheral surface of the cylindrical portion 38 corresponding to the annular ridges 43, 43 of the reduced diameter portion 44 formed on the inner peripheral surface 42 of the cylindrical portion 38, the thickness of the synthetic resin sleeve 23 is increased. The thickness can be made almost uniform, and the occurrence of sink marks and deformation due to uneven thickness can be prevented.
[0042]
The synthetic resin sleeve 23 has an inner periphery of the inner bush 22 in which the bottom surface of the annular recess 41 on the outer peripheral surface of the cylindrical portion 38, that is, the outer peripheral surface of the cylindrical portion 38 is inserted and held in the cylindrical recess 29 of the inner ring 31 of the outer bush 21. The annular flange 40 is slidably brought into contact with the surface, and the annular flange 40 is slidably inserted between the lip portion 28 of the inner ring 31 and the end face of the inner bush 22 inserted and held in the cylindrical recess 29, and the annular protrusion 39 Is arranged in the inner ring 31 so as to be slidably brought into contact with the locking protrusion 30 of the inner ring 31. A lip portion 28 is provided instead of the locking ridge portion 30 at the position of the locking ridge portion 30 of the inner ring 31, and a locking ridge is provided at the position of the lip portion 28 of the inner ring 31 instead of the lip portion 28. The annular flange 40 may be slidably inserted between the lip portion 28 of the inner ring 31 and the end face of the inner bush 22 inserted and held in the cylindrical recess 29, and the synthetic resin may be provided. The sleeve 23 may be arranged in the inner ring 31, and the synthetic resin sleeve 23 may be formed by omitting the annular protrusion 39.
[0043]
In the steering column device 20 described above, the column shaft 26 is inserted into the reduced diameter portion 44 formed on the inner peripheral surface 42 of the cylindrical portion 38 of the synthetic resin sleeve 23 with a tightening margin. The synthetic resin is formed between the inner peripheral surface of the inner bush 22 inserted and held in the cylindrical recess 29 of the inner ring 31 and the outer peripheral surface of the cylindrical portion 38 of the synthetic resin sleeve 23 through a sliding surface having a low friction coefficient. Therefore, smooth steering operation with low friction is possible.
[0044]
Further, since the outer peripheral surface not corresponding to the cylindrical recess 29 of the inner ring 31 and the inner peripheral surface of the outer ring 34 corresponding to the outer peripheral surface are integrally connected by the support legs 35 in the circumferential direction, the cylinder of the inner ring 31 Since the pressure input when the bearing 24 is press-fitted and fixed to the housing 25 is not directly applied to the concave portion 29, the inner diameter dimensional accuracy (roundness) of the inner bush 22 fitted and fixed to the cylindrical concave portion 29 is not affected. . Furthermore, even when the influence of the welding distortion due to the welding process adversely affects the inner diameter dimensional accuracy of the housing 25, the deviation in the inner diameter dimensional accuracy of the housing 25 does not directly affect the cylindrical recess 29 of the inner ring 31. The inner dimensional accuracy of the inner bush 22 to be inserted and held is not affected.
[0045]
The synthetic resin sleeve 23 shown in FIGS. 4 and 5 includes a cylindrical portion 38 and an annular flange 40 formed at one end of the cylindrical portion 38. The inner peripheral surface 42 is formed with a reduced diameter portion 44 including a plurality of protrusions 47 formed along the axial direction and in the circumferential direction. The inner diameter formed by the protrusion 47 has an inner diameter smaller than the inner diameter of the inner peripheral surface 42. The synthetic resin sleeve 23 shown in FIGS. 4 and 5 extends at least from the end opposite to the annular flange 40 formed at one end of the cylindrical portion 38 to the vicinity of the annular flange 40. Three slit grooves 48 are formed at equal intervals in the circumferential direction.
[0046]
Further, two annular recesses 46 are formed on the outer peripheral surface of the cylindrical portion 38 of the synthetic resin sleeve 23 shown in FIGS. 4 and 5 at a predetermined interval in the axial direction. It becomes a reservoir for lubricating oil.
[0047]
The synthetic resin sleeve 23 shown in FIGS. 4 and 5 is configured such that the outer peripheral surface of the cylindrical portion 38 is slidably brought into contact with the inner peripheral surface of the inner bush 22 in the same manner as the synthetic resin sleeve 23 shown in FIGS. The annular flange 40 is inserted between the lip portion 28 of the inner ring 31 and the end face of the inner bush 22 inserted and held in the cylindrical recess 29.
[0048]
The synthetic resin sleeve 23 shown in FIGS. 4 and 5 can provide the same effects as described above.
[0049]
In the above example, the lip portion 28 and the locking protrusion 30 are divided in the circumferential direction and provided on the inner ring 31. However, the lip portion 28 and the locking protrusion 30 are not divided in the circumferential direction. At least one of the strips 30 may be provided on the inner ring 31 over the entire circumference continuously in the circumferential direction.
[0050]
【The invention's effect】
According to the present invention, the column shaft that is inserted into the reduced diameter portion formed on the inner peripheral surface of the cylindrical portion of the synthetic resin sleeve with a tightening margin is the inner peripheral surface of the cylindrical bush that is inserted and held in the cylindrical concave portion of the inner ring. The bearing for the steering column enables smooth steering operation with low friction because it is supported through a sliding surface with a low coefficient of friction between the synthetic resins formed by the cylindrical portion outer surface of the sleeve made of synthetic resin An apparatus can be provided.
[0051]
In addition, according to the present invention, there is provided a steering column bearing capable of smoothly supporting the column shaft and performing a steering operation more smoothly without affecting the accuracy of the inner diameter of the sliding portion of the inner bush. A bearing device using this bearing can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a preferred embodiment of the present invention.
FIG. 2 is a left side view of the embodiment shown in FIG.
FIG. 3 is a right side view of the embodiment shown in FIG.
FIG. 4 is a front view of a synthetic resin sleeve.
FIG. 5 is a cross-sectional view of another embodiment of a synthetic resin sleeve.
6 is a left side view of the other mode shown in FIG. 5. FIG.
FIG. 7 is a cross-sectional view showing the prior art.
8 is a cross-sectional view taken along line VIII-VIII in FIG.
[Explanation of symbols]
20 Bearing device for steering column
21 Outer bush
22 Inner bush
23 Synthetic resin sleeve
24 Bearing
25 Housing
26 Column shaft
31 inner ring
34 Outer ring
35 Support legs
36 Reinforcement ribs
44 Reduced diameter section

Claims

It consists of a synthetic resin outer bush, an inner bush, and a synthetic resin sleeve. The outer bush is provided in the vicinity of one end of the cylindrical inner peripheral surface along the circumferential direction and projecting radially. An inner ring provided with a lip portion and a locking ridge portion that protrudes along the circumferential direction at a predetermined interval in the axial direction from the lip portion and cooperates with the lip portion and the cylindrical inner peripheral surface to define a cylindrical recess. And an outer ring having a plurality of protrusions along the axial direction on the outer peripheral surface, and an outer edge extending in the circumferential direction on the outer peripheral surface not corresponding to the cylindrical recess of the inner ring, and an inner edge extending in the circumferential direction. A support leg integrally connected to the inner peripheral surface of the outer ring corresponding to the outer peripheral surface, and extends from the outer peripheral surface corresponding to the lip portion of the inner ring to the support leg along the axial direction. Integrally connected to each of the inner peripheral surface and the support legs At least three reinforcing ribs, the inner bush is inserted and held in the cylindrical recess of the inner ring, and at least the inner peripheral surface is made of a synthetic bush, and the synthetic resin sleeve is a cylinder. And an annular flange provided at one end of the cylindrical portion, and a reduced diameter portion having an inner diameter smaller than the inner diameter of the inner peripheral surface, provided on the inner peripheral surface of the cylindrical portion. The synthetic resin sleeve is configured such that the outer peripheral surface of the cylindrical portion is slidably brought into contact with the inner peripheral surface of the cylindrical bush, and the annular flange portion is connected to the lip portion of the inner ring and the cylindrical concave portion. A steering column bearing, wherein the bearing is inserted between an end face of a cylindrical bush that is inserted and held and disposed in an inner ring.

The cylindrical bush has a three-layer structure comprising a thin steel plate, a metal sintered layer integrally formed on the surface of the thin steel plate, and a synthetic resin layer impregnated with the metal sintered layer. The steering column bearing according to claim 1, comprising a wound bush formed by winding in a cylindrical shape.

The cylindrical bush is composed of a thin steel plate and a synthetic resin sliding layer integrally formed on the surface of the thin steel plate, and the wound bush is formed by winding in a cylindrical shape with the synthetic resin sliding layer inside. The steering column bearing according to claim 1, comprising:

4. The reduced diameter portion of the synthetic resin sleeve comprises at least two annular ridges formed at predetermined intervals in the axial direction on the inner peripheral surface of the cylindrical portion. Steering column bearing.

The steering portion according to any one of claims 1 to 3, wherein the reduced diameter portion of the synthetic resin sleeve comprises a plurality of protrusions formed along the axial direction and in the circumferential direction on the inner peripheral surface of the cylindrical portion. Column bearing.

The bearing for a steering column according to any one of claims 1 to 5, wherein a slit is formed in the synthetic resin sleeve from an end portion of the cylindrical portion to the annular flange portion.

The synthetic resin sleeve has at least three slits extending from the end portion of the cylindrical portion to the vicinity of the annular flange portion, and is formed at equal intervals in the circumferential direction. Steering column bearing.

The steering column bearing according to any one of claims 1 to 7, wherein at least two annular grooves are formed on the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve at predetermined intervals in the axial direction.

It has a bearing made of an elastic synthetic resin outer bush, an inner bush, and a synthetic resin sleeve, and the outer bush is located in the circumferential direction near one end of the cylindrical inner peripheral surface and has a diameter. Lip projecting in the direction and a projecting projection projecting along the circumferential direction at a predetermined interval in the axial direction from the lip section and defining a cylindrical recess in cooperation with the lip section and the inner circumferential surface of the cylinder An inner ring having a ridge, an outer ring having a plurality of protrusions along the axial direction on the outer peripheral surface in the circumferential direction, and an outer periphery extending in the circumferential direction on the outer peripheral surface not corresponding to the cylindrical recess of the inner ring. A support leg integrally connected to the inner peripheral surface of the outer ring corresponding to the outer peripheral surface at the inner edge extending in the direction, and extending from the outer peripheral surface corresponding to the lip portion of the inner ring to the support leg along the axial direction. On the outer circumferential surface of the outer ring, the inner circumferential surface of the outer ring, and the support legs. A synthetic resin sleeve comprising at least three reinforcing ribs physically connected, and an inner bush comprising a cylindrical bush inserted and held in a cylindrical recess of an inner ring and having at least an inner peripheral surface formed of a synthetic resin Is a cylindrical portion, an annular flange provided at one end of the cylindrical portion, an inner peripheral surface of the cylindrical portion, and a reduced diameter having an inner diameter smaller than the inner diameter of the inner peripheral surface. The synthetic resin sleeve is configured such that the outer peripheral surface of the cylindrical portion is slidably brought into contact with the inner peripheral surface of the cylindrical bush, and the annular flange is connected to the lip portion of the inner ring. The bearing is inserted into the inner ring between the end face of the cylindrical bush inserted and held in the cylindrical recess, and the bearing is press-fitted into the housing at the protrusion on the outer peripheral surface of the outer ring. To the reduced diameter part of the bush made of synthetic resin The steering is characterized in that it is inserted with a margin and is supported via a sliding surface between synthetic resins formed by the inner peripheral surface of the cylindrical bush and the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve. Column bearing device.

The cylindrical bush has a three-layer structure comprising a thin steel plate, a metal sintered layer integrally formed on the surface of the thin steel plate, and a synthetic resin layer impregnated with the metal sintered layer. The bearing device for a steering column according to claim 9, comprising a wound bush formed by winding in a cylindrical shape with the inner side facing inward.

The cylindrical bush is composed of a thin steel plate and a synthetic resin sliding layer integrally formed on the surface of the thin steel plate, and the wound bush is formed by winding in a cylindrical shape with the synthetic resin sliding layer inside. The bearing device for a steering column according to claim 9, comprising:

12. The reduced diameter portion of the synthetic resin sleeve includes at least two annular protrusions formed on the inner peripheral surface of the cylindrical portion at predetermined intervals in the axial direction. Bearing device for steering column.

The steering portion according to any one of claims 9 to 11, wherein the diameter-reduced portion of the synthetic resin sleeve includes a plurality of protrusions formed along the axial direction and in the circumferential direction on the inner peripheral surface of the cylindrical portion. Column bearing device.

The bearing device for a steering column according to any one of claims 9 to 13, wherein a slit is formed in the synthetic resin sleeve from an end portion of the cylindrical portion to the annular flange portion.

The synthetic resin sleeve is formed with at least three slits extending from the end of the cylindrical portion to the vicinity of the annular flange at equal intervals in the circumferential direction. Bearing device for steering column.

The bearing device for a steering column according to any one of claims 9 to 15, wherein at least two annular grooves are formed on the outer peripheral surface of the cylindrical portion of the synthetic resin sleeve at predetermined intervals in the axial direction.