JP4303807B2

JP4303807B2 - Steering column bearing and bearing device using this bearing

Info

Publication number: JP4303807B2
Application number: JP21657998A
Authority: JP
Inventors: 良和坂入
Original assignee: Oiles Corp
Current assignee: Oiles Corp
Priority date: 1998-05-19
Filing date: 1998-07-31
Publication date: 2009-07-29
Anticipated expiration: 2018-07-31
Also published as: JP2000039021A

Description

【０００１】
【発明が属する技術分野】
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に関するものである。
【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、ボールベアリングまたは合成樹脂からなるすべ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。ボールベアリングは、その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が固定されるハウジングおよび該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】
合成樹脂からなるすべり軸受は、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、すべ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を生じる。
【０００４】
また、ハウジング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の外周面に取付ける場合、該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（真円度）に悪影響をもたらし、ハウジングに固定される軸受の内径寸法精度（真円度）を一層悪化させるという問題もある。
【０００５】
上記に鑑み本出願人は、先に特願平６−３４０６１１号（特開平８−１８４３１５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とともに、ハウジングの内径寸法精度（真円度）に影響を及ぼされないステアリングコラム用軸受装置を提案した。
【０００６】
この先行技術を図１０によって説明する。ステアリングコラム用軸受装置１は、ゴム弾性体あるい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２およびアウターブッシュ２内に挿入保持されるインナーブッシュ３からなる軸受４と軸受４が圧入固定されるパイプ状のハウジング５とインナーブッシュ３に支承されるコラムシャフト６とから構成されている。アウターブッシュ２は、円筒内周面７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のリップ部８およびリップ部８と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８と円筒内周面７と協同して円筒凹部９を画定する複数個の係止突条部１０を具備した内輪１１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凸条部１２および一方の端部に径方向外方に延設された環状鍔部１３を具備した外輪１４と、内輪１１の円筒凹部９に対応しない外周面と該外周面に対応する外輪１４の内周面とをその円周方向において一体的に連結する支持脚１５と、内輪１１のリップ部８に対応する外周面から支持脚１５まで延び、内輪１１の外周面と外輪１４の内周面と支持脚１５とに一体的に連結された３本の補強リブ１６とからなっている。インナーブッシュ３は、アウターブッシュ２の内輪１１のリップ部８と係止突条部１０との間の円筒凹部９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１４の外周面の凸条部１２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１１のリップ部８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軸受隙間を保持して支承されている。
【０００７】
【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、アイドリング時等のコラムシャフト６に負荷が作用しない状態では、コラムシャフト６はリップ部８に弾性支持されるので、コラムシャフト６に作用する振動は吸収され、コラムシャフト６とインナーブッシュ３との間の衝突音の発生は防止され、またステアリング操作時にコラムシャフト６に作用する負荷はインナーブッシュ３に適切なクリアランス（軸受隙間）をもって円滑に支承される、という前述した従来技術の問題点を解決するものであり、また、先行技術からなるステアリングコラム用軸受装置１は、内輪１１の円筒凹部９に対応しない外周面と該外周面に対応する外輪１４の内周面とがその円周方向において支持脚１５によって一体的に連結されているため、内輪１１の円筒凹部９には軸受４をハウジング５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９に挿入保持されるインナーブッシュ３の内径寸法精度（真円度）に影響が及ぼされない、という前述した問題点を解決するものであった。
【０００８】
しかしながら、上述した軸受が組込まれるステアリングコラムにおいては、コラム自体の剛性の向上化や車輌衝突時のハンドル収縮機構の追加等に伴い、コラムシャフトの大径化、ハウジングの小径化が進んでおり、当該軸受が組込まれる部位、すなわちコラムシャフトの外周面とハウジングの内周面との隙間が自ずから狭められ、上述した従来技術に対して数多くの利点を備えた先行技術の軸受をそのまま使用することはできないという問題点が新たに見出された。とくに、アウターブッシュの弾性力およびインナーブッシュの強度だけではハウジングの寸法精度の悪影響を吸収できないという問題である。
【０００９】
本発明は、先行技術の改良に係わり、先行技術における利点をそのまま生かすとともに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内径寸法精度（真円度）に影響を及ぼさないステアリングコラム用軸受およびこの軸受を用いた軸受装置を提供することにある。
【００１０】
本発明のステアリングコラム用軸受は、弾性を有するアウターブッシュとインナーブッシュとからなり、アウターブッシュは、内面に円筒内周面部と該円筒内周面部と環状段部を介して連続する拡径円筒面部と該円筒内周面部の一方の端部近傍に円周方向に沿いかつ径方向に突出したリップ部と該円筒内周面部の他方の端部に円周方向に沿いかつ径方向に突出するとともに該リップ部と円筒内周面部と協同して円筒凹部を画定する係止突部を具備した内輪と、外周面に軸方向に沿う凸条部を円周方向に複数個具備した外輪と、該内輪の外周面と外輪の内周面との間に環状凹部を形成して該内輪の一方の端部と該端部に対応する外輪の一方の端部とを一体に連結する連接部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連接部まで延び、内輪外周面と外輪内周面と連接部とを一体に連結する少なくとも３本の補強リブと、該補強リブに対応する内輪の円筒内周面部およびあるいは外輪の外周面にその軸方向にわたって形成された凹条溝を具備しており、該凹条溝は、該各々の凹条溝の開口部の円周方向幅が該各々の凹条溝に対応する補強リブの円周方向幅よりも大となるような大きさに形成されており、インナーブッシュは内輪の円筒凹部に保持されて構成されている。
【００１１】
また、上記の軸受を用いた軸受装置は、上記軸受が外輪外周面の凸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、アウターブッシュの内輪のリップ部に締代をもって摺接しているとともにインナーブッシュの内周面と所定の軸受隙間を保持して支承されている。
【００１２】
本発明のステアリングコラム用軸受およびこの軸受を用いた軸受装置において、アウターブッシュの内輪のリップ部および係止突部はそれぞれ、内輪の内周面に円周方向に沿って連続的に延設された環状のリップ部および係止突部であってもよく、あるいは内輪の内周面に円周方向に沿ってとびとびに配された複数個のものからなるものであってもよい。一つの好ましいリップ部は、当該リップ部の先端で形成される仮想円の直径（本発明でいうリップ部の内径）がインナーブッシュの内径より０．０２ｍｍ〜０．２０ｍｍ程度小さく形成されている。
【００１３】
弾性を有するアウターブッシュの材料としては、ゴム弾性体、弾性を有する合成樹脂を例示することができ、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）が４０〜６０、反発弾性値（ＪＩＳ−Ｋ６３０１）が５０〜８０を有していてゴム状の弾性挙動を呈するもので、例えばポリエステル・エーテル共重合体あるいはポリウレタン等を好ましい例として挙げることができる。
【００１４】
インナーブッシュとしては、薄鋼板とこの薄鋼板の表面に一体に接合された多孔質金属焼結層とこの多孔質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条片を、合成樹脂層を内側にして円筒状に捲回した巻きブッシュからなるものを、一つの好ましい例として提示し得る。
【００１５】
【発明の実施の形態】
つぎに本発明の実施の形態を、図に示す好ましい実施例に基づいて更に詳細に説明する。なお、本発明は実施例に何等限定されないのである。
【００１６】
【実施例】
図１乃至図５において、本例のステアリングコラム用軸受装置２０は、ゴム弾性体あるい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およびアウターブッシュ２１内に挿入保持されるインナーブッシュ２２からなる軸受２３と、軸受２３が圧入固定されるパイプ状のハウジング２４と、インナーブッシュ２２に支承されるコラムシャフト２５とから構成されている。
【００１７】
アウターブッシュ２１は、内面に円筒内周面部２６と該円筒内周面部２６と環状段部２７を介して連続する拡径円筒面部２８と該円筒内周面部２６の一方の端部近傍に円周方向に沿いかつ径方向に突出した複数個（本例では６個）のリップ部２９と該円筒内周面部２６の他方の端部に円周方向に沿いかつ径方向に突出するとともに該リップ部２９と円筒内周面部２６と協同して円筒凹部３０を画定する複数個（本例では６個）の係止突部３１を具備した内輪３２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凸条部３４と一方の端部に径方向外方に延設された環状鍔部３５を具備した外輪３６と、該内輪３２の外周面と外輪３６の内周面との間に環状凹部３３を形成して該内輪３２の一方の端部と該端部に対応する外輪３６の一方の端部とを一体に連結する連接部３７と、該内輪３２のリップ部２９に対応する外周面から軸方向に沿って連接部３７まで延び、内輪３２の外周面と外輪３６の内周面と連接部３７とを一体的に連結する少なくとも３本の補強リブ３８と、該補強リブ３８に対応する内輪３２の円筒内周面部２６にその軸方向にわたって形成された少なくとも３本の凹条溝３９を備えている。該凹条溝３９は、該各々の凹条溝３９の開口部の円周方向幅が該各々の凹条溝３９に対応する補強リブ３８の円周方向幅よりも大となるような大きさに形成されている。
【００１８】
アウターブッシュ２１において、外輪３６の端部に径方向外方に延設された環状鍔部３５は、軸受２３を後述するハウジング２４へ圧入するさい、ハウジング２４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２３をハウジング２４内の任意の位置に圧入固定する場合には必要としない。また、円筒内周面部２６と環状段部２７をもって連続する拡径円筒面部２８は、後述するインナーブッシュ２２を円筒凹部３０に挿入保持するさい、該インナーブッシュ２２の円筒凹部３０への挿入を容易に行わせるためのものである。
【００１９】
補強リブ３８は、円筒凹部３０が形成された部分の内輪３２を補強するものであり、本例では円周方向に均等にかつ径方向に相対応しないように３本配置されており、また、円筒内周面部２６の該補強リブ３８に対応する部位には凹条溝３９が形成されている。該凹条溝３９は、該各々の凹条溝３９の開口部の円周方向幅が該各々の凹条溝３９に対応する補強リブ３８の円周方向幅よりも大となるような大きさに形成されている。円筒内周面部２６に凹条溝３９を形成したのは、円筒凹部３０に挿入保持される後述のインナーブッシュ２２の内径寸法精度（真円度）に、軸受２３をハウジング２４に圧入固定するさいの圧入力の影響を及ぼさないためである。すなわち、本例のように、軸受２３が組込まれる部位、すなわちコラムシャフト２５の外周面とハウジング２４の内周面との隙間が狭められた場合、軸受２３を当該部位に圧入すると、圧入力が補強リブ３８を介してインナーブッシュ２２に作用することになるが、該補強リブ３８に対応する円筒内周面部２６、換言すればインナーブッシュ２２が挿入保持される円筒凹部３０に凹条溝３９が形成されているので、該圧入力は当該凹条溝３９を含む円筒内周面部２６の弾性変形により吸収されるので、圧入力が補強リブ３８を介してインナーブッシュ２２に作用することはなく、インナーブッシュ２２の真円度に影響を及ぼすことはない。
【００２０】
インナーブッシュ２２は、薄鋼板とこの薄鋼板の表面に一体に接合された多孔質金属焼結層とこの多孔質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条片を、合成樹脂層を内側にして円筒状に捲回した、所謂巻きブッシュからなる。図１中、符号４０は当該巻きブッシュの突き合わせ部である。
【００２１】
インナーブッシュ２２がアウターブッシュ２１の内輪３２の円筒凹部３０に挿入保持されて、軸受２３が構成される。この構成において、内輪３２の円筒内周面部２６の一方の端部近傍に円周方向に沿いかつ径方向に突出して形成された複数個のリップ部２９は、インナーブッシュ２２の内径ｄより僅かに小さい内径Ｄ（当該リップ部２９の先端で形成される仮想円の直径をいう）をもって径方向内側に突出して形成されているが、具体的には当該リップ部２９の内径がインナーブッシュ２２の内径より、当該インナーブッシュ２２とインナーブッシュ２２に支承されるコラムシャフト２５との間のクリアランス（軸受隙間）に相当する量、例えば、０．０２ｍｍ〜０．２０ｍｍだけ小さくなるように形成されている。また、係止突部３１の内径はインナーブッシュ２２の内径より大きく外径より小さく形成されている。したがって、インナーブッシュ２２は、内輪３２の円筒凹部３０内に挿入保持されることにより、インナーブッシュ２２の内輪３２からの抜け出しは防止される。
【００２２】
図６及び図７は、上述したステアリングコラム用軸受装置２０におけるアウターブッシュ２１の他の実施例を示す。すなわち、この実施例におけるアウターブッシュ２１０は、内面に円筒内周面部２６と該円筒内周面部２６と環状段部２７を介して連続する拡径円筒面部２８と該円筒内周面部２６の一方の端部近傍に円周方向に沿いかつ径方向に突出した複数個（本例では６個）のリップ部２９と該円筒内周面部２６の他方の端部に円周方向に沿いかつ径方向に突出するとともに該リップ部２９と円筒内周面部２６と協同して円筒凹部３０を画定する複数個（本例では６個）の係止突部３１を具備した内輪３２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凸条部３４と一方の端部に径方向外方に延設された環状鍔部３５を具備した外輪３６と、該内輪３２の外周面と外輪３６の内周面との間に環状凹部３３を形成して該内輪３２の一方の端部と該端部に対応する外輪３６の一方の端部とを一体に連結する連接部３７と、該内輪３２のリップ部２９に対応する外周面から軸方向に沿って連接部３７まで延び、内輪３２の外周面と外輪３６の内周面と連接部３７とを一体的に連結する少なくとも３本の補強リブ３８と、該補強リブ３８に対応する外輪３６の外周面にその軸方向にわたって形成された少なくとも３本の凹条溝４１を備えている。該凹条溝４１は、該各々の凹条溝４１の開口部の円周方向幅が該各々の凹条溝４１に対応する補強リブ３８の円周方向幅よりも大となるような大きさに形成されている。
【００２３】
図８及び図９は、上述したステアリングコラム用軸受装置２０におけるアウターブッシュ２１のさらに他の実施例を示す。すなわち、この実施例におけるアウターブッシュ２１１は、内面に円筒内周面部２６と該円筒内周面部２６と環状段部２７を介して連続する拡径円筒面部２８と該円筒内周面部２６の一方の端部近傍に円周方向に沿いかつ径方向に突出した複数個（本例では６個）のリップ部２９と該円筒内周面部２６の他方の端部に円周方向に沿いかつ径方向に突出するとともに該リップ部２９と円筒内周面部２６と協同して円筒凹部３０を画定する複数個（本例では６個）の係止突部３１を具備した内輪３２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凸条部３４と一方の端部に径方向外方に延設された環状鍔部３５を具備した外輪３６と、該内輪３２の外周面と外輪３６の内周面との間に環状凹部３３を形成して該内輪３２の一方の端部と該端部に対応する外輪３６の一方の端部とを一体に連結する連接部３７と、該内輪３２のリップ部２９に対応する外周面から軸方向に沿って連接部３７まで延び、内輪３２の外周面と外輪３６の内周面と連接部３７とを一体的に連結する少なくとも３本の補強リブ３８と、該補強リブ３８に対応する内輪３２の円筒内周面部２６にその軸方向にわたって形成された少なくとも３本の凹条溝３９及び該補強リブ３８に対応する外輪３６の外周面にその軸方向にわたって形成された少なくとも３本の凹条溝４１を備えている。該凹条溝３９及び凹条溝４１は、該各々の凹条溝３９及び凹条溝４１の開口部の円周方向幅が該各々の凹条溝３９及び凹条溝４１に対応する補強リブ３８の円周方向幅よりも大となるような大きさに形成されている。
【００２４】
以上のように構成されたステアリングコラム用軸受装置２０では、内輪３２の外周面と外輪３６の内周面と連接部３７とを一体に連結する補強リブ３８に対応する内輪３２の円筒内周面部２６およびあるいは補強リブ３８に対応する外輪３６の外周面にはその軸方向にわたって凹条溝３９およびあるいは凹条溝４１が形成されており、該凹条溝３９およびあるいは凹条溝４１は、該各々の凹条溝３９およびあるいは凹条溝４１の開口部の円周方向幅が該各々の凹条溝３９およびあるいは凹条溝４１に対応する補強リブ３８の円周方向幅よりも大となるような大きさに形成されているため、換言すれば、当該部位の肉厚が薄肉に形成されているため、軸受２３をハウジング２４に圧入固定するさいの圧入力は当該薄肉部の弾性変形によって吸収され、該内輪３２の円筒凹部３０には直接作用しないので、該円筒凹部３０に挿入保持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。したがって、インナーブッシュ２２とインナーブッシュ２２に支承されるコラムシャフト２５との間には適切なクリアランス（摺動隙間）が維持され、片当たり等の不具合を生じることなく円滑な摺動が行われる。
【００２５】
また、圧入力の影響はインナ−ブッシュ２２の内径寸法精度ばかりでなく、内輪３２のリップ部２９にも及ばず、而してリップ部２９のコラムシャフト２５に対する締代もまた、当該圧入力によっては影響されないので、コラムシャフト２５はリップ部２９に所定の締代をもって摺動自在にかつ弾性的に支承される。したがって、アイドリング時等のコラムシャフト２５に負荷が作用しない状態では、コラムシャフト２５はリップ部２９に弾性支持されるので、コラムシャフト２５に作用する振動は吸収され、コラムシャフト２５とインナ−ブッシュ２２との間の衝突音の発生は防止され、また、ステアリング操作時にコラムシャフト２５に作用する負荷はインナ−ブッシュ２２に上述した適切なクリアランスをもって円滑に支承される。
【００２６】
以上のように本発明によれば、内輪の外周面と外輪の内周面と連接部とを一体に連結する補強リブに対応する内輪の円筒内周面部およびあるいは外輪の外周面にその軸方向にわたって凹条溝が形成されており、該凹条溝は、該各々の凹条溝の開口部の円周方向幅が該各々の凹条溝に対応する補強リブの円周方向幅よりも大となるような大きさに形成されているため、換言すれば、当該部位の肉厚が薄肉に形成されているため、軸受をハウジングに圧入固定するさいの圧入力は当該薄肉部の弾性変形によって吸収され、該内輪の円筒凹部には直接作用しないので、該円筒凹部に挿入保持されるインナーブッシュの内径寸法精度（真円度）に影響が及ぼされず、インナーブッシュと該インナーブッシュに支承されるコラムシャフトとの間には適切なクリアランス（摺動隙間）が維持され、円滑な摺動が行われ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。
【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】本発明のアウタ−ブッシュを示す断面図である。
【図３】図２の右側面図である。
【図４】図２の左側面図である。
【図５】図１の要部拡大断面図である。
【図６】アウターブッシュの他の実施例を示す断面図である。
【図７】図６のＡ−Ａ線断面図である。
【図８】アウターブッシュのさらに他の実施例を示す断面図である。
【図９】図８のＢ−Ｂ線断面図である。
【図１０】先行技術を示す断面図である。
【符号の説明】
２０ステアリングコラム用軸受装置
２１、２１０、２１１アウタ−ブッシュ
２２インナ−ブッシュ
２３軸受
２４ハウジング
２５コラムシャフト
２６円筒内周面部
２９リップ部
３０円筒凹部
３１係止突部
３２内輪
３４凸条部
３６外輪
３７連接部
３８補強リブ
３９凹条溝
４１凹条溝[0001]
[Technical field to which the invention belongs]
The present invention relates to a steering column bearing for supporting a steering column shaft of an automobile.
[0002]
[Prior art]
Conventionally, a ball bearing or a plain bearing made of 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. Although the ball bearing has a stable friction torque, it is inferior in vibration absorption, and it is necessary to finish the dimensional accuracy of the housing to which the ball bearing is fixed and the column shaft supported by the ball bearing with high accuracy. In addition to the expensive point of the bearing itself, there is a problem that the processing cost is increased.
[0003]
A plain 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 slide 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 generation of the collision noise, a stick-slip phenomenon occurs, which causes a problem that the stability of the friction torque is hindered.
[0004]
In addition, when a member (bracket) for fixing the housing to the vehicle body is attached to the outer peripheral surface of the housing by welding, the influence of welding distortion caused by the welding has an adverse effect on the inner diameter dimensional accuracy (roundness) of the housing. There is also a problem that the inner diameter dimensional accuracy (roundness) of the bearing fixed to the housing is further deteriorated.
[0005]
In view of the above, the present applicant previously described in Japanese Patent Application No. 6-340611 (Japanese Patent Laid-Open No. Hei 8-184315: hereinafter referred to as “prior art”), the load acting on the column shaft during steering operation (when the steering wheel is rotated). Is smoothly supported by the bearing, and when the load is not applied to the column shaft, such as when idling, the vibration acting on the shaft can be absorbed and the inner diameter dimensional accuracy (roundness) of the housing is affected. A steering column bearing device was proposed.
[0006]
This prior art will be described with reference to FIG. A steering column bearing device 1 includes a rubber elastic body or an outer bush 2 formed of an elastic synthetic resin and a bearing 4 including an inner bush 3 inserted and held in the outer bush 2 and a pipe into which the bearing 4 is press-fitted and fixed. And a column shaft 6 supported by the inner bush 3. The outer bush 2 is circular with a predetermined distance in the axial direction from a plurality of lip portions 8 and a plurality of lip portions 8 extending in the circumferential direction in the vicinity of one end of the cylindrical inner peripheral surface 7 and projecting in the radial direction. An inner ring 11 provided with a plurality of locking ridges 10 projecting along the circumferential direction and defining a cylindrical recess 9 in cooperation with the lip portion 8 and the cylindrical inner peripheral surface 7, and axially on the outer peripheral surface Corresponding to a plurality of ridges 12 formed along the circumference and in the circumferential direction and an outer ring 14 having an annular flange 13 extending radially outward at one end, and a cylindrical recess 9 of the inner ring 11 A support leg 15 that integrally connects the outer peripheral surface of the outer ring 14 corresponding to the outer peripheral surface and the inner peripheral surface of the outer ring 14 in the circumferential direction, and extends from the outer peripheral surface corresponding to the lip portion 8 of the inner ring 11 to the support leg 15. , Integrally connected to the outer peripheral surface of the inner ring 11, the inner peripheral surface of the outer ring 14 and the support leg 15. Is made up of three of the reinforcing ribs 16 for it was. The inner bush 3 is inserted and held in a cylindrical recess 9 between the lip portion 8 and the locking protrusion 10 of the inner ring 11 of the outer bush 2, and the outer bush 2 holding the inner bush 3 is connected to the outer ring 14. The column shaft 6 is slidably brought into sliding contact with the lip portion 8 of the inner ring 11 of the outer bush 2 with a margin, and is fixed to the inner peripheral surface of the inner bush 3 in a predetermined manner. It is supported while maintaining the bearing clearance.
[0007]
[Problems to be solved by the invention]
In the steering column bearing device 1 according to the above-described prior art, the column shaft 6 is elastically supported by the lip portion 8 when no load is applied to the column shaft 6 during idling or the like. Is absorbed, and the generation of collision noise between the column shaft 6 and the inner bush 3 is prevented, and the load acting on the column shaft 6 during steering operation is smoothly supported by the inner bush 3 with an appropriate clearance (bearing clearance). The steering column bearing device 1 according to the prior art corresponds to the outer peripheral surface not corresponding to the cylindrical recess 9 of the inner ring 11 and the outer peripheral surface. Since the inner peripheral surface of the outer ring 14 is integrally connected by the support leg 15 in the circumferential direction, Since the pressure input when the bearing 4 is press-fitted and fixed to the housing 5 is not directly applied to the cylindrical concave portion 9, the inner diameter dimensional accuracy (roundness) of the inner bush 3 inserted and held in the cylindrical concave portion 9 is affected. It was to solve the above-mentioned problem of not being performed.
[0008]
However, in the steering column in which the above-described bearing is incorporated, the column shaft is increased in diameter and the housing is reduced in diameter due to the improvement of the rigidity of the column itself and the addition of a handle contraction mechanism at the time of a vehicle collision. The part where the bearing is incorporated, that is, the gap between the outer peripheral surface of the column shaft and the inner peripheral surface of the housing is naturally narrowed, and the prior art bearing having many advantages over the above-described prior art is used as it is. A new problem was found that could not be done. In particular, there is a problem that the dimensional accuracy of the housing cannot be absorbed by only the elastic force of the outer bush and the strength of the inner bush.
[0009]
The present invention relates to improvements in the prior art, and has been made in order to take advantage of the prior art as it is and to solve the above problems. The object of the present invention is to improve the inner bushing inner diameter dimensional accuracy (roundness). An object of the present invention is to provide a steering column bearing that does not affect the bearing and a bearing device using the bearing.
[0010]
A bearing for a steering column according to the present invention comprises an elastic outer bush and an inner bush, and the outer bush has a cylindrical inner peripheral surface portion which is continuous with an inner surface via a cylindrical inner peripheral surface portion and the cylindrical inner peripheral surface portion and an annular step portion. And a lip portion protruding in the circumferential direction and radially in the vicinity of one end portion of the cylindrical inner peripheral surface portion, and protruding in the circumferential direction and radial direction at the other end portion of the cylindrical inner peripheral surface portion. An inner ring provided with a locking projection for defining a cylindrical recess in cooperation with the lip part and the cylindrical inner peripheral surface part, an outer ring provided with a plurality of protrusions along the axial direction on the outer peripheral surface in the circumferential direction, A connecting portion for forming an annular recess between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, and integrally connecting one end of the inner ring and one end of the outer ring corresponding to the end; Extends from the outer peripheral surface corresponding to the lip portion of the inner ring to the connecting portion along the axial direction The inner ring outer peripheral surface, the outer ring inner peripheral surface and the connecting portion are integrally connected to each other, and the cylindrical inner peripheral surface portion of the inner ring corresponding to the reinforcing rib and / or the outer peripheral surface of the outer ring are formed in the axial direction. and it comprises a concave groove that is, recessed grooves, rather than circumferential width of the reinforcing ribs circumferential width of the opening of the respective concave groove corresponds to the concave groove of the respective are formed in such a size becomes larger, the inner bushing is constructed is held in the inner ring of the cylindrical recess.
[0011]
Further, in the bearing device using the above-described bearing, the bearing is press-fitted into the housing at the protruding portion of the outer peripheral surface of the outer ring, and the column shaft is slidably contacted with the lip portion of the inner ring of the outer bush with an inner margin. The bearing is supported while maintaining a predetermined bearing gap with the inner peripheral surface of the bush.
[0012]
In the steering column bearing of the present invention and the bearing device using this bearing, the lip portion and the locking projection of the inner ring of the outer bush are each continuously extended along the circumferential direction on the inner peripheral surface of the inner ring. Alternatively, it may be an annular lip portion and a locking projection, or may be composed of a plurality of items that are arranged on the inner peripheral surface of the inner ring in a circumferential direction. One preferable lip portion is formed such that the diameter of the virtual circle formed at the tip of the lip portion (the inner diameter of the lip portion in the present invention) is smaller by 0.02 mm to 0.20 mm than the inner diameter of the inner bush.
[0013]
Examples of the material of the outer bush having elasticity include rubber elastic bodies and synthetic resins having elasticity. Examples of the synthetic resin having elasticity are flexible and strong, and generally have a Shore hardness (D-type). ) Has a resilience value (JIS-K6301) of 50 to 80 and exhibits a rubber-like elastic behavior. For example, a polyester-ether copolymer or polyurethane may be mentioned as a preferable example. it can.
[0014]
As the inner bush, a strip having a three-layer structure of a thin steel plate, a porous metal sintered layer integrally bonded to the surface of the thin steel plate, and a synthetic resin layer impregnated and coated on the porous metal sintered layer As a preferred example, a material comprising a wound bush wound in a cylindrical shape with a synthetic resin layer inside may be presented.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in more detail based on preferred examples shown in the drawings. In addition, this invention is not limited to an Example at all.
[0016]
【Example】
1 to 5, a steering column bearing device 20 according to this embodiment includes an outer bush 21 formed of a rubber elastic body or a synthetic resin having elasticity, and an inner bush 22 inserted and held in the outer bush 21. 23, a pipe-like housing 24 into which the bearing 23 is press-fitted and fixed, and a column shaft 25 supported by the inner bush 22.
[0017]
The outer bush 21 has a cylindrical inner peripheral surface portion 26 on its inner surface, a diameter-enlarging cylindrical surface portion 28 continuous via the cylindrical inner peripheral surface portion 26 and an annular step portion 27, and a circumference in the vicinity of one end of the cylindrical inner peripheral surface portion 26. A plurality of (six in this example) lip portions 29 projecting in the radial direction along the direction and the other end portion of the cylindrical inner peripheral surface portion 26 along the circumferential direction and projecting in the radial direction and the lip portion an inner ring 32 provided with the locking projection 31 of the (six in this example) a plurality defining a 29 and the cylindrical inner peripheral surface portion 26 and the cylindrical recess 30 cooperate, and circumferentially along the outer peripheral surface in the axial direction An outer ring 36 having a plurality of ridges 34 formed in the direction and an annular flange 35 extending radially outward at one end, an outer peripheral surface of the inner ring 32 and an inner periphery of the outer ring 36 An annular recess 33 is formed between the inner ring 32 and an outer surface corresponding to the end. A connecting portion 37 that integrally connects one end of the inner ring 36 and an outer peripheral surface corresponding to the lip portion 29 of the inner ring 32 extend from the outer peripheral surface of the inner ring 32 to the connecting portion 37 along the axial direction. At least three reinforcing ribs 38 integrally connecting the inner peripheral surface and the connecting portion 37, and at least three reinforcing ribs 38 formed on the cylindrical inner peripheral surface portion 26 of the inner ring 32 corresponding to the reinforcing rib 38 over the axial direction. A concave groove 39 is provided. The concave groove 39 has a size such that the circumferential width of the opening of each concave groove 39 is larger than the circumferential width of the reinforcing rib 38 corresponding to each concave groove 39. Is formed.
[0018]
In the outer bush 21, the annular flange 35 extending radially outward at the end of the outer ring 36 is necessary when the bearing 23 is fixed to the end of the housing 24 when the bearing 23 is press-fitted into the housing 24 described later. Therefore, it is not necessary when the bearing 23 is press-fitted and fixed at an arbitrary position in the housing 24. Further, the enlarged diameter cylindrical surface portion 28 which is continuous with the cylindrical inner peripheral surface portion 26 and the annular step portion 27 facilitates the insertion of the inner bush 22 into the cylindrical recess 30 when the inner bush 22 described later is inserted and held in the cylindrical recess 30. It is for letting you do it.
[0019]
The reinforcing ribs 38 reinforce the portion of the inner ring 32 in which the cylindrical recess 30 is formed, and in this example, three reinforcing ribs 38 are arranged so as to be even in the circumferential direction and not correspond to the radial direction. A concave groove 39 is formed in a portion corresponding to the reinforcing rib 38 of the cylindrical inner peripheral surface portion 26. The concave groove 39 has a size such that the circumferential width of the opening of each concave groove 39 is larger than the circumferential width of the reinforcing rib 38 corresponding to each concave groove 39. Is formed. The concave groove 39 is formed in the cylindrical inner peripheral surface portion 26 when the bearing 23 is press-fitted and fixed to the housing 24 in accordance with the inner diameter dimensional accuracy (roundness) of an inner bush 22 to be inserted and held in the cylindrical concave portion 30. This is because there is no influence of the pressure input. That is, as in this example, when the part into which the bearing 23 is assembled, that is, the gap between the outer peripheral surface of the column shaft 25 and the inner peripheral surface of the housing 24 is narrowed, when the bearing 23 is press-fitted into the part, The inner rib 22 acts on the inner rib 22 via the reinforcing rib 38, and the concave groove 39 is formed in the cylindrical inner peripheral surface portion 26 corresponding to the reinforcing rib 38, in other words, in the cylindrical concave portion 30 in which the inner bush 22 is inserted and held. Since the pressure input is absorbed by the elastic deformation of the cylindrical inner peripheral surface portion 26 including the concave groove 39, the pressure input does not act on the inner bush 22 via the reinforcing rib 38. The roundness of the inner bush 22 is not affected.
[0020]
The inner bush 22 is a strip having a three-layer structure of a thin steel plate, a porous metal sintered layer integrally bonded to the surface of the thin steel plate, and a synthetic resin layer impregnated with the porous metal sintered layer. Is a so-called wound bush wound in a cylindrical shape with the synthetic resin layer inside. In FIG. 1, the code | symbol 40 is the butt | matching part of the said winding bush.
[0021]
The inner bush 22 is inserted and held in the cylindrical recess 30 of the inner ring 32 of the outer bush 21 to constitute the bearing 23. In this configuration, the plurality of lip portions 29 formed in the vicinity of one end of the cylindrical inner peripheral surface portion 26 of the inner ring 32 along the circumferential direction and projecting in the radial direction are slightly larger than the inner diameter d of the inner bush 22. Although it has a small inner diameter D (referred to as the diameter of a virtual circle formed at the tip of the lip portion 29), it protrudes radially inward. Specifically, the inner diameter of the lip portion 29 is the inner diameter of the inner bush 22. Thus, the inner bush 22 and the column shaft 25 supported by the inner bush 22 are formed so as to be smaller by an amount corresponding to a clearance (bearing gap), for example, 0.02 mm to 0.20 mm. The inner diameter of the locking projection 31 is larger than the inner diameter of the inner bush 22 and smaller than the outer diameter. Accordingly, the inner bush 22 is inserted and held in the cylindrical recess 30 of the inner ring 32, so that the inner bush 22 is prevented from coming out of the inner ring 32.
[0022]
6 and 7 show another embodiment of the outer bush 21 in the steering column bearing device 20 described above. That is, the outer bush 210 in this embodiment has one of the cylindrical inner peripheral surface portion 26, the cylindrical inner peripheral surface portion 26, and the cylindrical inner peripheral surface portion 26 that continues through the annular step portion 27. A plurality of (six in this example) lip portions 29 projecting radially in the circumferential direction in the vicinity of the end portion and the other end portion of the cylindrical inner peripheral surface portion 26 along the circumferential direction and in the radial direction. An inner ring 32 having a plurality of (six in this example) locking protrusions 31 that project and define the cylindrical recess 30 in cooperation with the lip portion 29 and the cylindrical inner peripheral surface portion 26 and an axial direction on the outer peripheral surface A plurality of ridges 34 formed along the circumferential direction and an outer ring 36 having an annular flange 35 extending radially outward at one end, and an outer peripheral surface of the inner ring 32; An annular recess 33 is formed between the inner ring 32 and the inner peripheral surface of the outer ring 36. A connecting portion 37 that integrally connects one end of the outer ring 36 and one end of the outer ring 36 corresponding to the end, and a connecting portion 37 along the axial direction from the outer peripheral surface corresponding to the lip portion 29 of the inner ring 32. At least three reinforcing ribs 38 that integrally connect the outer peripheral surface of the inner ring 32, the inner peripheral surface of the outer ring 36, and the connecting portion 37, and the axis of the outer peripheral surface of the outer ring 36 corresponding to the reinforcing rib 38. At least three concave grooves 41 formed in the direction are provided. The concave groove 41 is sized so that the circumferential width of the opening of each concave groove 41 is larger than the circumferential width of the reinforcing rib 38 corresponding to each concave groove 41. Is formed.
[0023]
8 and 9 show still another embodiment of the outer bush 21 in the steering column bearing device 20 described above. That is, the outer bush 211 in this embodiment has one of the cylindrical inner peripheral surface portion 26, the cylindrical inner peripheral surface portion 26, and the cylindrical inner peripheral surface portion 26 continuous through the annular stepped portion 27. A plurality of (six in this example) lip portions 29 projecting radially in the circumferential direction in the vicinity of the end portion and the other end portion of the cylindrical inner peripheral surface portion 26 along the circumferential direction and in the radial direction. an inner ring 32 provided with the locking projection 31 of the plurality (six in this embodiment) which defines a cylindrical recess 30 in cooperation with the lip portion 29 and the cylindrical inner peripheral surface portion 26 with protruding, axial to the outer peripheral surface An outer ring 36 having a plurality of ridges 34 formed along the direction and in the circumferential direction, an annular flange 35 extending radially outward at one end, and an outer peripheral surface of the inner ring 32 An annular recess 33 is formed between the inner ring 32 and the inner peripheral surface of the outer ring 36. A connecting portion 37 that integrally connects one end of the outer ring 36 and one end of the outer ring 36 corresponding to the end, and a connecting portion 37 along the axial direction from the outer peripheral surface corresponding to the lip portion 29 of the inner ring 32. And at least three reinforcing ribs 38 integrally connecting the outer peripheral surface of the inner ring 32, the inner peripheral surface of the outer ring 36 and the connecting portion 37, and the cylindrical inner peripheral surface portion 26 of the inner ring 32 corresponding to the reinforcing rib 38. Are provided with at least three concave grooves 39 formed along the axial direction on the outer peripheral surface of the outer ring 36 corresponding to the reinforcing ribs 38. The groove groove 39 and the groove groove 41 are reinforcing ribs whose circumferential width of the opening of each groove groove 39 and groove groove 41 corresponds to each groove groove 39 and groove groove 41. It is formed in a size that is larger than the circumferential width of 38.
[0024]
In the steering column bearing device 20 configured as described above, the cylindrical inner peripheral surface portion of the inner ring 32 corresponding to the reinforcing rib 38 integrally connecting the outer peripheral surface of the inner ring 32, the inner peripheral surface of the outer ring 36, and the connecting portion 37. 26 and / or an outer peripheral surface of the outer ring 36 corresponding to the reinforcing rib 38 is formed with a groove groove 39 and / or a groove groove 41 in the axial direction thereof. The circumferential width of the opening of each groove groove 39 and / or groove groove 41 is larger than the circumferential width of the reinforcing rib 38 corresponding to each groove groove 39 and / or groove groove 41. In other words, since the thickness of the portion is thin, the pressure input when the bearing 23 is press-fitted and fixed to the housing 24 is caused by elastic deformation of the thin portion. absorption Is, since the cylindrical recess 30 of the inner race 32 does not act directly, it is not adversely affect the inside diameter dimensional accuracy of the inner bush 22 which is inserted and held in the cylindrical recess 30 (roundness). Therefore, an appropriate clearance (sliding gap) is maintained between the inner bush 22 and the column shaft 25 supported by the inner bush 22, and smooth sliding is performed without causing a problem such as one-side contact.
[0025]
In addition, the influence of the pressure input is not limited to the accuracy of the inner diameter of the inner bush 22 but also the lip portion 29 of the inner ring 32, and the tightening allowance of the lip portion 29 with respect to the column shaft 25 is also affected by the pressure input. Therefore, the column shaft 25 is slidably and elastically supported by the lip 29 with a predetermined allowance. Therefore, in a state where no load is applied to the column shaft 25 during idling or the like, the column shaft 25 is elastically supported by the lip portion 29, so that vibrations acting on the column shaft 25 are absorbed, and the column shaft 25 and the inner bushing 22 are absorbed. And the load acting on the column shaft 25 during the steering operation is smoothly supported by the inner bush 22 with the above-described appropriate clearance.
[0026]
As described above, according to the present invention, the cylindrical inner peripheral surface portion of the inner ring corresponding to the reinforcing rib for integrally connecting the outer peripheral surface of the inner ring, the inner peripheral surface of the outer ring, and the connecting portion, and / or the outer peripheral surface of the outer ring in the axial direction. A groove is formed over the groove, and the circumferential width of the opening of each groove is larger than the circumferential width of the reinforcing rib corresponding to each groove. In other words, since the thickness of the part is thin, the pressure input when the bearing is press-fitted and fixed to the housing is caused by elastic deformation of the thin part. Since it is absorbed and does not directly act on the cylindrical recess of the inner ring, it does not affect the inner dimensional accuracy (roundness) of the inner bush inserted and held in the cylindrical recess, and is supported by the inner bush and the inner bush. Suitable for the column shaft Clearance (sliding gap) is maintained, smooth sliding can be provided a bearing device for a steering column to be performed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a preferred embodiment of the present invention.
FIG. 2 is a cross-sectional view showing an outer bush of the present invention.
FIG. 3 is a right side view of FIG. 2;
4 is a left side view of FIG. 2;
5 is an enlarged cross-sectional view of a main part of FIG.
FIG. 6 is a cross-sectional view showing another embodiment of the outer bush.
7 is a cross-sectional view taken along line AA in FIG.
FIG. 8 is a cross-sectional view showing still another embodiment of the outer bush.
9 is a cross-sectional view taken along line BB in FIG.
FIG. 10 is a cross-sectional view showing the prior art.
[Explanation of symbols]
20 Bearing device for steering column 21, 210, 211 Outer bush 22 Inner bush 23 Bearing 24 Housing 25 Column shaft 26 Cylindrical inner peripheral surface portion 29 Lip portion 30 Cylindrical recess 31 Locking protrusion 32 Inner ring 34 Protruding portion 36 Outer ring 37 Connecting portion 38 Reinforcing rib 39 Concave groove 41 Concave groove

Claims

The outer bush comprises an elastic outer bush and an inner bush, and the outer bush has one of an inner circumferential surface portion of the cylinder, an enlarged cylindrical surface portion continuous with the inner circumferential surface portion of the cylinder and an annular step portion, and one of the inner circumferential surface portion of the cylinder. A lip portion projecting in the circumferential direction and in the radial direction in the vicinity of the end portion, and a lip portion projecting in the circumferential direction and in the radial direction at the other end portion of the cylindrical inner peripheral surface portion, and the lip portion and the cylindrical inner peripheral surface portion An inner ring having a locking projection that cooperates to define a cylindrical recess, an outer ring having a plurality of ridges along the axial direction on the outer circumferential surface, and an outer circumferential surface of the inner ring and an inner circumference of the outer ring. An outer peripheral surface corresponding to a connecting portion for integrally connecting one end portion of the inner ring and one end portion of the outer ring corresponding to the end portion, and an inner ring lip portion. Extending along the axial direction from the inner ring to the connecting portion, the inner ring outer peripheral surface, the outer ring inner peripheral surface and the connecting portion At least three reinforcing ribs that are integrally connected to each other, and a cylindrical inner peripheral surface portion of the inner ring corresponding to the reinforcing rib and / or an outer peripheral surface of the outer ring, and a groove groove formed in the axial direction. The groove is formed in a size such that the circumferential width of the opening of each groove is larger than the circumferential width of the reinforcing rib corresponding to each groove. A bearing for a steering column, wherein the bush is held in a cylindrical recess of the inner ring.

The bearing for a steering column according to claim 1, wherein the inner diameter of the lip portion of the inner ring of the outer bush is slightly smaller than the inner diameter of the inner bush.

The inner bush has a three-layer structure of a thin steel plate, a porous metal sintered layer integrally formed on the surface of the thin steel plate, and a synthetic resin layer impregnated and coated on the porous metal sintered layer. The bearing for a steering column according to claim 1 or 2, comprising a wound bush formed by winding in a cylindrical shape with the resin layer inside.

A bearing comprising an elastic outer bush and an inner bush is provided. The outer bush has a cylindrical inner peripheral surface portion, an enlarged cylindrical surface portion continuous with the inner peripheral surface portion of the cylinder and an annular step portion, and the cylinder. A lip portion extending in the circumferential direction and radially in the vicinity of one end portion of the inner peripheral surface portion, and a lip portion protruding in the circumferential direction and in the radial direction at the other end portion of the cylindrical inner peripheral surface portion And an inner ring provided with a locking projection for defining a cylindrical recess in cooperation with the cylindrical inner peripheral surface part, an outer ring provided with a plurality of protruding ridges along the axial direction on the outer peripheral surface, and an outer periphery of the inner ring A connecting portion that integrally connects one end of the inner ring and one end of the outer ring corresponding to the end by forming an annular recess between the surface and the inner peripheral surface of the outer ring, and a lip of the inner ring It extends from the outer peripheral surface corresponding to the part to the connecting part along the axial direction, and At least three reinforcing ribs for integrally connecting the inner peripheral surface and the connecting portion, and a cylindrical groove formed on the inner peripheral surface of the inner ring corresponding to the reinforcing rib and / or the outer peripheral surface of the outer ring over the axial direction. The groove groove is provided with a size such that the circumferential width of the opening of each groove groove is larger than the circumferential width of the reinforcing rib corresponding to each groove groove. The inner bush is held in a cylindrical recess of the outer bush, the bearing is press-fitted into the housing at the convex portion of the outer peripheral surface of the outer ring, and the column shaft is a lip of the inner ring of the outer bush. A bearing device for a steering column, wherein the bearing device is slidably contacted with a tightening margin and is supported while maintaining a predetermined bearing gap with an inner peripheral surface of the inner bush.

The bearing device for a steering column according to claim 4, wherein the inner diameter of the lip portion of the inner ring of the outer bush is slightly smaller than the inner diameter of the inner bush.

The inner bush has a three-layer structure of a thin steel plate, a porous metal sintered layer integrally formed on the surface of the thin steel plate, and a synthetic resin layer impregnated and coated on the porous metal sintered layer. The bearing device for a steering column according to claim 4 or 5, comprising a wound bush formed by winding in a cylindrical shape with the resin layer inside.