JP4100148B2

JP4100148B2 - Electric power steering device

Info

Publication number: JP4100148B2
Application number: JP2002347883A
Authority: JP
Inventors: 雅史魚田; 博之重村
Original assignee: JTEKT Corp
Current assignee: JTEKT Corp
Priority date: 2002-11-29
Filing date: 2002-11-29
Publication date: 2008-06-11
Anticipated expiration: 2022-11-29
Also published as: JP2004181990A

Description

【０００１】
【発明の属する技術分野】
本発明は操舵補助力の発生源としてモータを用いてなる電動式パワーステアリング装置に関する。
【０００２】
【従来の技術】
車両用の電動式パワーステアリング装置は、操舵補助用のモータ及び該モータの回転力を舵取手段に伝える減速歯車機構を備えており、操舵手段の操舵に応じた舵取手段の動作を前記モータの回転により補助し、舵取りのための運転者の労力負担を軽減するように構成されている。
【０００３】
減速歯車機構はモータの出力軸に軸継手を介して継合され、反モータ側に軸部を有するウォームと、該ウォームに噛合し、前記舵取機構に繋がるウォームホイールと、前記ウォームの他端部をウォーム及びウォームホイールの回転中心間距離が長短となる方向へ移動可能に支持する軸受部材と、該軸受部材を移動操作する操作体と、該操作体及び前記軸受部材の間に介在され、ウォームのウォームホイールとの噛合部に予圧を加えるべく前記軸受部材を径方向へ付勢するコイルバネとを備え、前記噛合部に予圧を加えることによりバックラッシュ量を少なくするように構成されている。（例えば、特許文献１。）
【０００４】
また、ウォームは前記モータの出力軸との継合部に対しモータと反対側へ離隔した部分が転がり軸受を介してハウジング内に回転自在に支持されている。ところが、転がり軸受には複数の転動体を介して嵌合された内輪及び外輪間に軸長方向隙間があるため、この軸長方向隙間をなくする必要がある。つまり、転がり軸受の軸長方向隙間によってウォームが軸長方向へガタつき、このガタつきによって発生する異音が車室の内部に洩れることになり、運転者に不快感を与えることになるため、前記軸長方向隙間をなくする必要がある。
【０００５】
この軸長方向隙間をなくする一手段として、転がり軸受の外輪の一側に当接する調節環を前記ハウジング内に螺着し、該調節環を回転操作することにより転がり軸受の外輪及び内輪を軸長方向へ相対移動させることによりウォームに予圧を加えて軸長方向隙間をなくし、ウォームの軸長方向へのガタつきをなくするようにしてある。
【０００６】
ところで、減速歯車機構のウォーム歯車等は回転中心線に対しその歯すじが回転方向へ捩じれており、ウォームからウォームホイールへ回転トルクが加わるとき、換言すればモータの回転によって操舵補助する場合、ウォームがウォームホイールの歯すじに沿って径方向へ動くように分力（以下噛合反力と云う）が発生し、該噛合反力によりウォームが径方向へ押圧されて揺動し、雄形継手部の周面が雌形継手部に当接して叩き音が発生し易くなるため、雄形継手部及び雌形継手部の間にグリースを塗布により充填し、前記叩き音を低減するようにしてある。
【０００７】
【特許文献１】
特開２００２−２１９４３号公報
【０００８】
【発明が解決しようとする課題】
ところが、従来の電動式パワーステアリング装置にあっては、ウォームの揺動によって雄形継手部及び雌形継手部の間のグリースが雌形継手部の開口端から外部へ流出することになり、グリース量が減少し、叩き音が発生し易くなり、改善策が要望されていた。また、ウォームの軸長方向へのガタつきをなくするための調節環はウォームの周りに配置されているため、ウォームよりも大径寸法の調節環が必要であり、さらに、ウォームの周りが大形となり、改善策が要望されていた。
【０００９】
本発明は斯る事情に鑑みてなされたものであり、主たる目的は雄形継手部及び雌形継手部の間に充填された潤滑剤の流出を防ぐことができ、しかも、付勢手段を小形にできるとともに、駆動歯車の周りを小形にできる電動式パワーステアリング装置を提供することにある。
【００１０】
【課題を解決するための手段】
第１発明に係る電動式パワーステアリング装置は、モータの出力軸に雄形継手部及び雌形継手部を介して継合され、反モータ側に軸部を有する駆動歯車と、該駆動歯車に噛合し、舵取手段に繋がる従動歯車と、前記軸部を支持し駆動歯車及び従動歯車の回転中心間距離が長短となる方向への移動が可能な軸受部材と、該軸受部材を収容する収容孔を有する支持部材と、前記駆動歯車を反モータ側へ付勢する付勢手段とを備え、前記モータの回転によって操舵補助するようにした電動式パワーステアリング装置において、前記雄形継手部及び雌形継手部の少なくとも一方は雄形継手部及び雌形継手部の間に充填される潤滑剤の流出を防ぐための流出止環を備えており、前記雄形継手部は端面から軸長方向へ窪んだ凹所を有し、該凹所に前記付勢手段を収容してあり、前記流出止環はその内周面及び外周面の間に、軸長方向の寸法が径方向の寸法よりも小さい撓み部を有することを特徴とする。
【００１１】
第１発明にあっては、雄形継手部及び雌形継手部の間に充填されている潤滑剤が雌形継手部の開口端から流出するのを防ぐことができるため、雄形継手部及び雌形継手部の叩き音を抑制しつつ経年使用することができる。また、付勢手段は雄形継手部の凹所に収容されているため、付勢手段を小形にでき、さらに、付勢手段の周りを小形にでき、電動式パワーステアリング装置の全体を小形にできる。また、流出止環を内周面及び外周面の間の撓み部で撓ませ易いため、駆動歯車及び従動歯車の噛合部のバックラッシュ量の調整代を充分に確保することができるとともに、流出止環の潤滑剤流出止め機能をより一層高めることができ、噛合部のバックラッシュ量の調整代を充分に確保することができる駆動歯車が前記噛合反力によって頻繁に揺動する場合においても、潤滑剤の流出を防ぐことができ、雄形継手部及び雌形継手部の叩き音を低減できる。
【００１６】
第２発明に係る電動式パワーステアリング装置は、モータの出力軸に雄形継手部及び雌形継手部を介して継合され、反モータ側に軸部を有する駆動歯車と、該駆動歯車に噛合し、舵取手段に繋がる従動歯車と、前記軸部を支持し駆動歯車及び従動歯車の回転中心間距離が長短となる方向への移動が可能な軸受部材と、該軸受部材を収容する収容孔を有する支持部材と、前記駆動歯車を反モータ側へ付勢する付勢手段とを備え、前記モータの回転によって操舵補助するようにした電動式パワーステアリング装置において、前記雄形継手部及び雌形継手部の少なくとも一方は雄形継手部及び雌形継手部の間に充填される潤滑剤の流出を防ぐための流出止環を備えており、前記雄形継手部は端面から軸長方向へ窪んだ凹所を有し、該凹所に前記付勢手段を収容してあり、前記流出止環は複数個が近傍となるように並置されていることを特徴とする。
【００１７】
第２発明にあっては、雄形継手部及び雌形継手部の間に充填されている潤滑剤が雌形継手部の開口端から流出するのを防ぐことができるため、雄形継手部及び雌形継手部の叩き音を抑制しつつ経年使用することができる。また、付勢手段は雄形継手部の凹所に収容されているため、付勢手段を小形にでき、さらに、付勢手段の周りを小形にでき、電動式パワーステアリング装置の全体を小形にできる。しかも、雌形継手部の開口端から潤滑剤が流出するのを２段階で防ぐことができるため、流出止環の潤滑剤流出止め機能をより一層高めることができ、駆動歯車が前記噛合反力によって頻繁に揺動する場合においても、潤滑剤の流出を防ぐことができ、雄形継手部及び雌形継手部の叩き音を低減できる。
【００１８】
【発明の実施の形態】
以下本発明をその実施の形態を示す図面に基づいて詳述する。
実施の形態１
図１は本発明に係る電動式パワーステアリング装置の実施の形態１の構成を示す減速歯車機構部分の拡大断面図、図２は電動式パワーステアリング装置の全体部分の構成を示す断面図、図３は駆動歯車及び従動歯車と支持部材の支持孔との関連を示す説明図である。
【００１９】
電動式パワーステアリング装置は、操舵補助用のモータ１と、該モータ１の出力軸１ａに軸継手２を介して継合される駆動歯車としてのウォーム３及び該ウォーム３に噛合する従動歯車としてのウォームホイール４を有する減速歯車機構Ａと、ウォームホイール４を支持する回転軸（後記する）を有し、ウォームホイール４に繋がる舵取手段５とを備えている。
【００２０】
この舵取手段５は、一端部が舵取りのための操舵輪Ｂに繋がり、他端部に筒部５１ａを有する第１の操舵軸５１と、筒部５１ａ内に挿入されてその一端部が第１の操舵軸５１の筒部５１ａに連結され、操舵輪Ｂに加わる操舵トルクの作用によって捩れるトーションバー５２と、他端部がトーションバー５２の他端部に連結され、減速歯車機構Ａに繋がる回転軸としての第２の操舵軸５３とを備え、該第２の操舵軸５３がユニバーサルジョイントを介して例えばラックピニオン式の舵取機構（不図示）に繋がる。
【００２１】
減速歯車機構Ａのウォーム３は両端に軸部３ａ，３ｂを有しており、一端の軸部３ａが転がり軸受６を介して支持部材７に回転自在に支持された状態でモータ１の出力軸１ａに継合され、他端の軸部３ｂが円柱形の軸受部材８を介して支持部材７に支持されている。なお、軸部３ａは転がり軸受６の内輪６ａに圧入されている。軸部３ａの途中には転がり軸受６の内輪６ａの一端と向き合い、ウォーム３の内輪６ａとの相対移動を規制するフェールセールとしてのＣ形リング等の規制環９が着脱可能に取付けられている。ウォームホイール４は回転軸５の途中に嵌合固定されている。
【００２２】
支持部材７はウォーム３を収容し、該ウォーム３の軸部３ａ，３ｂを、転がり軸受６及び軸受部材８を介して回転自在に支持した第１収容部７ａと、ウォームホイール４を収容し、該ウォームホイール４を第２の操舵軸５３及び該第２の操舵軸５３に嵌合された２つの転がり軸受１０，１１を介して支持した第２収容部７ｂとを有する。
【００２３】
第１収容部７ａはウォーム３の軸長方向に長くなっており、その長手方向一端部には転がり軸受６を嵌合支持する支持孔７１及び該支持孔７１に連なるねじ孔７２及びモータ取付部７３が設けられており、ねじ孔７２に転がり軸受６を固定するためのねじ環１２が螺着されている。また、モータ取付部７３にモータ１が取付けられている。
【００２４】
第２収容部７ｂは転がり軸受１０，１１を嵌合支持する２つの支持孔７４，７５が設けられている。
支持孔７１の中心と支持孔７４，７５の中心との間の中心間距離Ｌは、ウォーム３のピッチ円直径φｄのφｄ／２と、ウォームホイールのピッチ円直径φＤのφＤ／２とを加算した寸法と等しいか、又は、φｄ／２とφＤ／２とを加算した寸法よりも小さくなるように設定してある。
【００２５】
この寸法の設定により、ウォーム３は転がり軸受６への支持部を中心としてウォーム３及びウォームホイール４の回転中心の平行域（図のＣ−Ｃ域）とほぼ平行になるか、又は、回転中心の平行域Ｃ−Ｃに対して軸部３ａ側（モータ側）の回転中心間距離Ｈ１が、軸部３ｂ側（反モータ側）の回転中心間距離Ｈ２よりも短くなるように傾斜する。
【００２６】
モータ１の出力軸１ａとウォーム３の軸部３ａとはセレーションを有する雄形継手部２１及び雌形継手部２２を介して継合されている。雄形継手部２１は軸部３ａの周面にセレーションを設けることにより構成されており、また、雌形継手部２２は出力軸１ａに嵌合固定された筒部材２３の内側にセレーションを設けることにより構成されており、雄形継手部２１と雌形継手部２２との間に径方向隙間Ｓ１ができるように雄形継手部２１及び雌形継手部２２がセレーション嵌合されている。この雄形継手部２１及び雌形継手部２２の間にはグリースからなる潤滑剤が塗布により充填されている。
【００２７】
雄形継手部２１の反モータ側端部には、セレーションの谷部直径以下の寸法の環状溝２１ａが設けられており、また、雌形継手部２２の開口端部には、セレーションの谷部直径以上の寸法の環状凹部２２ａが設けられている。環状溝２１ａにはその外周面が環状凹部２２ａに接触して雄形継手部２１及び雌形継手部２２の間に充填されている潤滑剤の流出を防ぐための流出止環１３が嵌合により保持されている。尚、環状凹部２２ａは雌形継手部２２の開口側の端縁から設けられている。また、環状凹部２２ａは雌形継手部２２の開口側の端縁近傍に溝状に形成してもよい。
【００２８】
雄形継手部２１のモータ側端面、換言すればウォーム３の一端には軸長方向へ窪んだ凹所２１ｂが設けられている。この凹所２１ｂには出力軸１ａの端面にその一端が当接してウォーム３を反モータ側へ付勢する付勢手段としてのコイルバネ１４が収容されている。
【００２９】
このコイルバネ１４は前記回転中心の平行域Ｃ−Ｃと平行的に付勢するようにしてあり、この付勢力がウォーム３の一端で、軸部３ａの転がり軸受６への支持部中心Ｏに対して回転中心間距離Ｈ１が長くなる位置に加わり、ウォーム３が前記したように回転中心の平行域Ｃ−Ｃに対して傾斜している場合、該ウォーム３を傾斜角度が小さくなる方向へ揺動させるようにしてある。また、コイルバネ１４の付勢力は軸部３ａから規制環９を介して内輪６ａに伝動され、転がり軸受６の軸長方向隙間をなくする。
【００３０】
図４は流出止環の構成を示す拡大断面である。
流出止環１３は例えば図４の(a) 〜(e) のように内周面及び外周面の間に、軸長方向の寸法が径方向の寸法よりも小さい撓み部１３ａを有するゴム等の弾性材料からなる。
図４(a) の流出止環１３は断面形状を径方向の寸法が軸長方向の寸法よりも長い略楕円形にしてあり、内周面及び外周面と径方向中央部との間の内側部分及び外側部分を撓み部１３ａとしてある。
図４(b) の流出止環１３は断面形状を内周側及び外周側に２つの接触環部１３ｂ，１３ｂを有する略Ｘ字形にしてあり、内周側及び外周側の各接触環部１３ｂを撓み部１３ａとしてある。
図４(c) の流出止環１３は断面形状を略エ字形にしてあり、内側部分及び外側部分の間の径方向中央部分を撓み部１３ａとしてある。
図４(d) の流出止環１３は断面形状を略コ字形にしてあり、換言すればオイルシールからなり、内側部分及び外側部分の間の径方向中央部分を撓み部１３ａとしてある。
図４(e) の流出止環１３は断面形状を内周側に１つの接触環部１３ｃを有し、外周側に２つの接触環部１３ｃを有する略Ｙ字形にしてあり、内周側及び外周側の各接触環部１３ｃを撓み部１３ａとしてある。
【００３１】
第１収容部７ａの他端部には、ウォーム３の他端の軸部３ｂが挿入される凹孔７６及び該凹孔７６の内面に臨み、軸部３ｂの径方向に向けて穿設、換言すればウォーム３をウォームホイール４に向けて押付ける方向に穿設された円柱形の収容孔７７が設けられている。この収容孔７７には軸部３ｂが回転自在に嵌合される軸受部材８と、該軸受部材８を前記押付ける方向へ付勢するコイルバネからなる弾性体１５と、収容孔７７の外部への開放部を閉じる閉孔部材１５とが収容されている。また、収容孔７７の外部への開放側にはねじ部７８が設けられており、該ねじ部７８に閉孔部材１６が螺着されている。
【００３２】
この閉孔部材１６と軸受部材８との間には径方向隙間Ｓ１よりも大きい隙間Ｓ２が設けられており、噛合反力等によって回転中心間距離Ｈ２が長くなる方向へウォーム３が動く際に、このウォーム３の動きを径方向隙間Ｓ１部分で規制し、軸受部材８が閉孔部材１６に当接しないようにしてある。
【００３３】
軸受部材８はその軸長方向の途中、換言すれば収容孔７７に沿って移動する移動方向の途中に前記移動方向と直交するように穿設された軸受孔８ａが設けられており、該軸受孔８ａに軸部３ｂが回転可能に嵌合されたすべり軸受１７を挿入固定してあり、該すべり軸受１７を介して軸部３ｂを軸受部材８に支持してある。
【００３４】
尚、支持部材７は第２収容部７ｂに連なる第３収容部７ｃを有しており、トーションバー１７の捩れに応じた操舵軸５１，５３の相対回転変位量によって操舵輪Ｂに加わる操舵トルクを検出するトルクセンサ１８が第３収容部７ｃに収容されており、該トルクセンサ１８が検出したトルク等に基づいてモータ１が駆動制御されるように構成されている。
【００３５】
以上のように構成された電動式パワーステアリング装置において、モータ１及び減速歯車機構Ａを組み込む場合、例えば雌形継手部２２内にグリースからなる潤滑剤が塗布により充填された状態で、ウォーム３の雄形継手部２１が出力軸１ａの雌形継手部２２に挿入され、セレーション嵌合される。この場合、雄形継手部２１の反モータ側端部に設けられた流出止環１３が、雌形継手部２２の開口端部に設けられた環状凹部２２ａに接触するため、雌形継手部２２内の潤滑剤が雌形継手部２２の開口端部から外部へ流出するのを防ぐことができる。従って、雄形継手部２１及び雌形継手部２２の叩き音を抑制しつつ経年使用することができる。
【００３６】
また、出力軸１ａの雌形継手部２２とウォーム３の雄形継手部２１とがセレーション嵌合された場合、雄形継手部２１及び雌形継手部２２の間に径方向隙間Ｓ１が生ずる。また、転がり軸受６に支持されたウォーム３は転がり軸受６の内輪６ａと外輪６ｂとの間の隙間によって転がり軸受６への支持部（軸部３ａ）を中心として揺動し、ウォーム３及び雄形継手部２１の回転中心が雌形継手部２２及び出力軸１ａの中心に対して前記径方向隙間Ｓ１の範囲内で傾斜することが可能になる。
【００３７】
そして、支持孔７１及び支持孔７４，７５の中心間距離Ｌと、ウォーム３のピッチ円直径φｄ及びウォームホイール４のピッチ円直径φＤとの関係が、Ｌ＜φｄ／２＋φＤ／２である場合、ウォーム３は転がり軸受６への支持部を中心として前記回転中心の平行域Ｃ−Ｃに対してモータ側の回転中心間距離Ｈ１が、反モータ側の回転中心間距離Ｈ２よりも短くなるように傾斜する。
【００３８】
この傾斜したウォーム３は、転がり軸受６よりもモータ１側でコイルバネ１４により前記回転中心の平行域Ｃ−Ｃと平行的に付勢されるため、ウォーム３は転がり軸受６への支持部を中心として傾斜角度が小さくなる方向へ揺動する。この揺動によりウォーム３及びウォームホイール４の噛合部に予圧を加えることができ、噛合部のバックラッシュ量を少なくすることができる。また、コイルバネ１４は転がり軸受６よりもモータ１側でウォーム３を反モータ側へ付勢するため、転がり軸受６の軸長方向隙間をなくし、ウォーム３の軸長方向へのガタつきをなくすることができる。
【００３９】
支持孔７１及び支持孔７４，７５の中心間距離Ｌと、ウォーム３のピッチ円直径φｄ及びウォームホイール４のピッチ円直径φＤとの関係が、Ｌ＝φｄ／２＋φＤ／２である場合、ウォーム３は前記回転中心の平行域Ｃ−Ｃとほぼ平行になる。この平行な状態のウォーム３は、転がり軸受６よりもモータ１側でコイルバネ１４により前記回転中心の平行域Ｃ−Ｃと平行的に付勢されるため、前記噛合部のバックラッシュ量を少なくすることができる。また、コイルバネ１４は転がり軸受６よりもモータ１側でウォーム３を反モータ側へ付勢するため、転がり軸受６の軸長方向隙間をなくし、ウォーム３の軸長方向へのガタつきをなくすることができる。
【００４０】
また、モータ１の回転によって操舵補助する場合において、噛合反力等によって回転中心間距離Ｈ２が長くなる方向へウォーム３が動く際には雄形継手部２１の周面が雌形継手部２２に当接し、ウォーム３の動きが制限される。この場合、閉孔部材１６と軸受部材８との間の隙間Ｓ２は径方向隙間Ｓ１よりも大きく設定されているため、ウォーム３の軸部３ｂを支持した軸受部材８が閉孔部材１６に当接するのを防ぐことができ、軸受部材８及び閉孔部材１６間での音鳴りをなくすることができる。このように音鳴りをなくすることができるため、前記した特許文献１のように軸受部材８及び閉孔部材１６間に緩衝部材を設ける必要がなく、部品点数を少なくすることができる。また、軸受部材８及び閉孔部材１６間にはコイルバネからなる弾性体１５が介されているため、ウォーム３の前記した動きを抑制することができ、雄形継手部２１の周面が雌形継手部２２に当接するのを防ぐことも可能である。また、弾性体１５に代えて、付勢手段を雌形継手部２２及び規制環９との間に設けることも可能である。
【００４１】
また、流出止環１３は図４に示すように、内周面及び外周面の間に、軸長方向の寸法が径方向の寸法よりも小さい撓み部１３ａを有するため、ウォーム３の揺動量を充分に確保した場合においても、潤滑剤の流出を防ぐことができ、雄形継手部２１及び雌形継手部２２の叩き音を低減できる。
【００４２】
尚、以上説明した実施の形態では閉孔部材１６及び軸受部材８間の隙間Ｓ２を径方向隙間Ｓ１よりも大きく設定したが、その他、径方向隙間Ｓ１及び隙間Ｓ２が等しくなるように設定してもよいし、また、隙間Ｓ２が径方向隙間Ｓ１よりも小さくなるように設定してもよい。この場合、軸受部材８及び閉孔部材１６間に介したコイルバネからなる弾性体１５によって軸受部材８及び閉孔部材１６間での音鳴りを低減できる。
【００４３】
実施の形態２
図５は電動式パワーステアリング装置の実施の形態２の構成を示す要部の拡大断面図である。
この実施の形態２の電動式パワーステアリング装置は、雄形継手部２１の反モータ側端部に図４の流出止環１３を並置したものである。図５の(a) は軸長方向に離隔する２つの環状溝２１ｃ，２１ｃを設け、各環状溝２１ｃに流出止環１３を挿入してある。図５の(b) は２つの流出止環１３を挿入することが可能な幅寸法の環状溝２１ｄを設け、該環状溝２１ｄに２つの流出止環１３を挿入してある。
【００４４】
実施の形態２にあっては、雌形継手部２２の開口端から潤滑剤が流出するのを２段階で防ぐことができるため、流出止環１３の潤滑剤流出止め機能をより一層高めることができる。従って、ウォーム３が前記噛合反力によって頻繁に揺動する場合においても、潤滑剤の流出を防ぐことができ、雄形継手部２１及び雌形継手部２２の叩き音を低減できる。
その他の構成及び作用は実施の形態１と同様であるため、同様の部品については同じ符号を付し、その詳細な説明及び作用効果の説明を省略する。
【００４５】
実施の形態３
図６は電動式パワーステアリング装置の実施の形態３の構成を示す要部の拡大断面図である。
この実施の形態３の電動式パワーステアリング装置は、雄形継手部２１の反モータ側端部に図４の流出止環１３と、該流出止環１３の一側に接触する略皿ばね形状のバックアップ環１９とを並置したものである。
実施の形態３において、流出止環１３及びバックアップ環１９は１つの環状溝２１ｅに挿入されている。
【００４６】
実施の形態３にあっては、ウォーム３の揺動によって流出止環１３が撓む場合、該流出止環１３の撓み力がバックアップ環１９に伝動され、該バックアップ環１９も撓むため、流出止環１３の撓みを抑制できる。
その他の構成及び作用は実施の形態１と同様であるため、同様の部品については同じ符号を付し、その詳細な説明及び作用効果の説明を省略する。
【００４７】
実施の形態４
図７は電動式パワーステアリング装置の実施の形態４の構成を示すもので、(a) は要部の拡大断面図、(b) は(a) のVII −VII 線の断面図である。
この実施の形態４の電動式パワーステアリング装置は、雄形継手部２１及び雌形継手部２２をセレーション嵌合する代わりに、雄形継手部２１及び雌形継手部２２をスプライン嵌合し、雄形継手部２１のモータ側端部と雌形継手部との間に雄形継手部２１の周面が雌形継手部２２に当接するのを抑制する弾性環２０を設けたものである。
【００４８】
実施の形態４において、雄形継手部２１及び雌形継手部２２の周面には断面形状が四角形となるスプラインが設けられている。また、雄形継手部２１のモータ側端部には環状凹部２１ｆが設けられており、該環状凹部２１ｆに弾性環２０が嵌合保持されている。
【００４９】
実施の形態４にあっては、雄形継手部２１及び雌形継手部２２のスプラインの側面同士が出力軸１ａの回転方向と直交的に接触するため、雄形継手部２１及び雌形継手部２２の継合部分の強度をセレーションに比べて高めることができる。
また、ウォーム３が転がり軸受６への支持部を中心として揺動する場合、弾性環２０が撓み、雄形継手部２１の周面が雌形継手部２２に当接するのを防ぐことができ、雄形継手部２１及び雌形継手部２２間での音鳴りを減少させることができる。
その他の構成及び作用は実施の形態１と同様であるため、同様の部品については同じ符号を付し、その詳細な説明及び作用効果の説明を省略する。
【００５０】
実施の形態５
図８は電動式パワーステアリング装置の実施の形態５の構成を示すもので、(a) は要部の拡大断面図、(b) は(a) のVIII−VIII線の断面図である。
この実施の形態５の電動式パワーステアリング装置は、雄形継手部２１及び雌形継手部２２をセレーション嵌合、スプライン嵌合する代わりに、雄形継手部２１及び雌形継手部２２の間にキー３０を設け、雄形継手部２１のモータ側端部と雌形継手部２２との間に雄形継手部２１の周面が雌形継手部２２に当接するのを抑制する弾性環２０を設けたものである。
【００５１】
実施の形態５において、雄形継手部２１及び雌形継手部２２の周面で周方向に離隔した２つの位置にはキー溝が設けられており、各キー溝にキー３０が嵌合されている。また、雄形継手部２１のモータ側端部には環状凹部２１ｆが設けられており、該環状凹部２１ｆに弾性環２０が嵌合保持されている。
【００５２】
実施の形態５にあっては、雄形継手部２１及び雌形継手部２２の相対回転をキー３０によって防ぐことができ、出力軸１ａの回転を雌形継手部２２からキー３０を介して雄形継手部２１に伝動することができるため、雄形継手部２１及び雌形継手部２２の継合部分の強度をセレーションに比べて高めることができる。
また、ウォーム３が転がり軸受６への支持部を中心として揺動する場合、弾性環２０が撓み、雄形継手部２１の周面が雌形継手部２２に当接するのを防ぐことができ、雄形継手部２１及び雌形継手部２２間での音鳴りを減少させることができる。
その他の構成及び作用は実施の形態１と同様であるため、同様の部品については同じ符号を付し、その詳細な説明及び作用効果の説明を省略する。
【００５３】
実施の形態６
図９は電動式パワーステアリング装置の実施の形態６の構成を示す要部の拡大断面図である。
この実施の形態６の電動式パワーステアリング装置は、雄形継手部２１及び雌形継手部２２を可撓性を有する弾性体３１により継合したものである。
【００５４】
実施の形態６において、雄形継手部２１の端面及び雌形継手部２２には断面が四角形の嵌合孔２１ｇ，２２ｂが設けられており、角柱形の弾性体３１の一端部を嵌合孔２１ｇに嵌合し、弾性体３１の他端部を嵌合孔２２ｂに嵌合し、出力軸１ａの回転を雌形継手部２２から弾性体３１を介して雄形継手部２１に伝動するようにしてある。また、雄形継手部２１の端面と雌形継手部２２の開口端との間はウォーム３の揺動を許容する以上の寸法で離隔している。
【００５５】
実施の形態６にあっては、ウォーム３の揺動量を充分に確保することができ、しかも、雄形継手部２１及び雌形継手部２２の継合部分での音鳴りをなくすることができ、さらに、出力軸１ａの回転を伝動する場合に弾性体３１を捩じらせることができるため、操舵感を向上できる。
その他の構成及び作用は実施の形態１と同様であるため、同様の部品については同じ符号を付し、その詳細な説明及び作用効果の説明を省略する。
【００５６】
実施の形態７
図１０は電動式パワーステアリング装置の実施の形態７の構成を示す要部の拡大断面図である。
この実施の形態７の電動式パワーステアリング装置は、雄形継手部２１及び雌形継手部２２を可撓性を有する弾性体３２により継合し、さらに、弾性体３２の撓み量を制限する制限部２１ｈを設けたものである。
【００５７】
実施の形態７において、雄形継手部２１のモータ側の端部には立方体形状の嵌合凸部２１ｊ及び該嵌合凸部２１ｊに連なり、嵌合凸部２１ｊよりも大形で立方体形状の制限部２１ｈが設けられており、また、雌形継手部２２には制限部２１ｈよりも大形で断面が四角形の嵌合孔２２ｃが設けられている。尚、この嵌合孔２２ｃは嵌合凸部２１ｊよりも長い寸法にしてある。
【００５８】
弾性体３２は断面が四角形の環部材からなり、この弾性体３２の内側が嵌合凸部２１ｊに嵌合されている。そして、嵌合孔２２ｃが弾性体３２の外側に嵌合されることにより雄形継手部２１及び雌形継手部２２が弾性体３２により継合される。
【００５９】
実施の形態７にあっては、ウォーム３の揺動量を充分に確保することができ、しかも、雄形継手部２１及び雌形継手部２２の継合部分での音鳴りをなくすることができ、さらに、ウォーム３の揺動により弾性体３２が一定量以上に撓む場合、雌形継手部２２の開口端部が制限部２１ｈに当接し、弾性体３２の撓み量を制限することができるため、弾性体３２の損傷を防ぐことができる。また、出力軸１ａの回転を伝動する場合に弾性体３２を捩じらせることができるため、操舵感を向上できる。
その他の構成及び作用は実施の形態１と同様であるため、同様の部品については同じ符号を付し、その詳細な説明及び作用効果の説明を省略する。
【００６０】
実施の形態８
図１１は電動式パワーステアリング装置の実施の形態８の構成を示す要部の拡大断面図である。
この実施の形態８の電動式パワーステアリング装置は、実施の形態６の弾性体３１によりウォーム３を反モータ側へ付勢するようにしたものである。
【００６１】
実施の形態８において、雄形継手部２１の端面と雌形継手部２２の開口端との間は弾性体３１を軸長方向に撓ませることができる間隔以上の寸法で離隔しており、弾性体３１を介して雄形継手部２１及び雌形継手部２２を継合する場合に弾性体３１を軸長方向へ撓ませるようにしてある。
【００６２】
実施の形態８にあっては、伝動用の弾性体３１が付勢ばねを兼ねるため、部品点数を少なくすることができる。
その他の構成及び作用は実施の形態１、６と同様であるため、同様の部品については同じ符号を付し、その詳細な説明及び作用効果の説明を省略する。
【００６３】
実施の形態９
図１２は電動式パワーステアリング装置の実施の形態９の構成を示す要部の拡大断面図である。
この実施の形態９の電動式パワーステアリング装置は、実施の形態６の弾性体３１の周りで、雄形継手部２１の端面と雌形継手部２２の開口端との間にウォーム３を反モータ側へ付勢するコイルバネ３３を設けたものである。
【００６４】
実施の形態９において、雄形継手部２１の端面と雌形継手部２２の開口端との間はコイルバネ３３を介在することが出来る寸法で離隔している。
その他の構成及び作用は実施の形態１、６と同様であるため、同様の部品については同じ符号を付し、その詳細な説明及び作用効果の説明を省略する。
【００６５】
尚、以上説明した実施の形態ではモータ１の出力軸１ａが雌形継手部２２を有し、ウォーム３の軸部３ａが雄形継手部２１を有する構成としたが、その他、出力軸１ａが雄形継手部２１を有し、軸部３ａが雌形継手部２２を有する構成としてもよい。
また、以上説明した実施の形態の減速歯車機構Ａは、ウォーム３である駆動歯車及びウォームホイール４である従動歯車を備えたウォーム歯車である他、ベベルギヤであってもよい。
【００６６】
【発明の効果】
以上詳述したように第１発明によれば、雄形継手部及び雌形継手部の間に充填されている潤滑剤が雌形継手部の開口端から流出するのを防ぐことができ、雄形継手部及び雌形継手部の叩き音を抑制しつつ経年使用することができる。しかも、噛合部のバックラッシュ量の調整代を充分に確保することができる駆動歯車が前記噛合反力によって頻繁に揺動する場合においても、潤滑剤の流出を防ぐことができ、雄形継手部及び雌形継手部の叩き音を低減できる。また、付勢手段を小形にできるとともに、付勢手段の周りを小形にでき、電動式パワーステアリング装置の全体を小形にできる。
【００６８】
第２発明によれば、雄形継手部及び雌形継手部の間に充填されている潤滑剤が雌形継手部の開口端から流出するのを防ぐことができ、雄形継手部及び雌形継手部の叩き音を抑制しつつ経年使用することができる。しかも、噛合部のバックラッシュ量の調整代を充分に確保することができる駆動歯車が前記噛合反力によって頻繁に揺動する場合においても、潤滑剤の流出を防ぐことができ、雄形継手部及び雌形継手部の叩き音を低減できる。また、付勢手段を小形にできるとともに、付勢手段の周りを小形にでき、電動式パワーステアリング装置の全体を小形にできる。
【図面の簡単な説明】
【図１】本発明に係る電動式パワーステアリング装置の実施の形態１の構成を示す減速歯車機構部分の拡大断面図である。
【図２】本発明に係る電動式パワーステアリング装置の全体部分の構成を示す断面図である。
【図３】本発明に係る電動式パワーステアリング装置の駆動歯車及び従動歯車と支持部材の支持孔との関連を示す説明図である。
【図４】本発明に係る電動式パワーステアリング装置の流出止環の構成を示す拡大断面図である。
【図５】本発明に係る電動式パワーステアリング装置の実施の形態２の構成を示す要部の拡大断面図である。
【図６】本発明に係る電動式パワーステアリング装置の実施の形態３の構成を示す要部の拡大断面図である。
【図７】本発明に係る電動式パワーステアリング装置の実施の形態４の構成を示すもので、(a) は要部の拡大断面図、(b) は(a) のVII −VII 線の断面図である。
【図８】本発明に係る電動式パワーステアリング装置の実施の形態５の構成を示すもので、(a) は要部の拡大断面図、(b) は(a) のVIII−VIII線の断面図である。
【図９】本発明に係る電動式パワーステアリング装置の実施の形態６の構成を示す要部の拡大断面図である。
【図１０】本発明に係る電動式パワーステアリング装置の実施の形態７の構成を示す要部の拡大断面図である。
【図１１】本発明に係る電動式パワーステアリング装置の実施の形態８の構成を示す要部の拡大断面図である。
【図１２】本発明に係る電動式パワーステアリング装置の実施の形態９の構成を示す要部の拡大断面図である。
【符号の説明】
１モータ
１ａ出力軸
３ウォーム（駆動歯車）
３ｂ軸部
４ウォームホイール（従動歯車）
５舵取手段
７支持部材
７７収容孔
８軸受部材
２１雄形継手部
２１ｂ凹所
２２雌形継手部
１３流出止環
１３ａ撓み部
１４コイルバネ（付勢手段）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric power steering apparatus using a motor as a generation source of steering assist force.
[0002]
[Prior art]
An electric power steering apparatus for a vehicle includes a motor for assisting steering and a reduction gear mechanism that transmits a rotational force of the motor to the steering means, and the operation of the steering means according to the steering of the steering means is the motor. It is configured to assist with the rotation of the vehicle and reduce the labor burden on the driver for steering.
[0003]
The reduction gear mechanism is connected to the output shaft of the motor via a shaft coupling, has a shaft portion on the side opposite to the motor, a worm wheel meshed with the worm and connected to the steering mechanism, and the other end of the worm A bearing member that movably supports the portion in a direction in which the distance between the rotation centers of the worm and the worm wheel becomes longer, an operation body that moves the bearing member, and is interposed between the operation body and the bearing member. A coil spring that urges the bearing member in a radial direction to apply a preload to a meshing portion of the worm with the worm wheel is configured to reduce a backlash amount by applying a preload to the meshing portion. (For example, Patent Document 1)
[0004]
In addition, a portion of the worm that is spaced apart from the motor to the joint portion with the output shaft of the motor is rotatably supported in the housing via a rolling bearing. However, since the rolling bearing has a gap in the axial length direction between the inner ring and the outer ring fitted via a plurality of rolling elements, it is necessary to eliminate this axial length gap. In other words, the worm rattles in the axial length direction due to the axial length gap of the rolling bearing, and abnormal noise generated by this rattle leaks into the passenger compartment, giving the driver an unpleasant feeling, It is necessary to eliminate the axial length direction clearance.
[0005]
As a means for eliminating the axial length clearance, an adjustment ring that contacts one side of the outer ring of the rolling bearing is screwed into the housing, and the outer ring and the inner ring of the rolling bearing are pivoted by rotating the adjustment ring. Relative movement in the longitudinal direction applies preload to the worm so as to eliminate the axial length direction clearance, thereby eliminating backlash in the axial direction of the worm.
[0006]
By the way, the worm gear of the reduction gear mechanism has a tooth line twisted in the rotation direction with respect to the center line of rotation, and when rotational torque is applied from the worm to the worm wheel, in other words, when assisting steering by rotating the motor, Generates a component force (hereinafter referred to as a meshing reaction force) so that the worm wheel moves in the radial direction along the worm wheel teeth, and the worm is pressed in the radial direction by the meshing reaction force to oscillate. Since the peripheral surface of the contact portion is in contact with the female joint portion and a hitting sound is easily generated, grease is applied between the male joint portion and the female joint portion to reduce the hitting sound. .
[0007]
[Patent Document 1]
JP 2002-211943 A
[0008]
[Problems to be solved by the invention]
However, in the conventional electric power steering apparatus, the grease between the male joint part and the female joint part flows out from the open end of the female joint part due to the swing of the worm. The amount has decreased and it has become easier to generate a hitting sound, and an improvement measure has been demanded. In addition, since the adjusting ring for eliminating the backlash in the axial direction of the worm is arranged around the worm, an adjusting ring having a larger diameter than that of the worm is required, and further, the area around the worm is larger. As a result, improvement measures were requested.
[0009]
The present invention has been made in view of such circumstances, and a main object of the present invention is to prevent the lubricant filled between the male joint portion and the female joint portion from flowing out. Another object of the present invention is to provide an electric power steering device that can be made compact and can be made compact around the drive gear.
[0010]
[Means for Solving the Problems]
  An electric power steering apparatus according to a first aspect of the present invention is connected to an output shaft of a motor via a male joint and a female joint, and has a drive gear having a shaft on the side opposite to the motor, and meshes with the drive gear. And a driven gear connected to the steering means, a bearing member that supports the shaft portion and is movable in a direction in which the distance between the rotation centers of the drive gear and the driven gear becomes longer and shorter, and a receiving hole for receiving the bearing member In the electric power steering apparatus, the male joint portion and the female shape are provided with a support member having a biasing means, and a biasing means for biasing the drive gear toward the non-motor side. At least one of the joint parts is provided with an outflow stop ring for preventing outflow of lubricant filled between the male joint part and the female joint part.The male joint has a recess recessed in the axial direction from the end surface, and the urging means is accommodated in the recess, and the outflow stop ring is between the inner peripheral surface and the outer peripheral surface. In addition, it has a bending portion whose axial length dimension is smaller than the radial dimension.It is characterized by that.
[0011]
  In the first invention, since the lubricant filled between the male joint portion and the female joint portion can be prevented from flowing out from the opening end of the female joint portion, the male joint portion and It can be used over time while suppressing the beating sound of the female joint.Further, since the urging means is accommodated in the recess of the male joint portion, the urging means can be made smaller, and the area around the urging means can be made smaller, and the entire electric power steering apparatus can be made smaller. it can. In addition, since the outflow stop ring is easily bent at the bent portion between the inner peripheral surface and the outer peripheral surface, a sufficient allowance for adjusting the backlash amount of the meshing portion of the driving gear and the driven gear can be secured, and the outflow stop is ensured. Even when the drive gear that can further enhance the ring lubricant outflow prevention function and sufficiently secure the allowance for adjusting the backlash amount of the meshing portion is frequently swung by the meshing reaction force, lubrication is possible. The outflow of the agent can be prevented, and the beating sound of the male joint and the female joint can be reduced.
[0016]
  First2The electric power steering apparatus according to the invention isA drive gear joined to the output shaft of the motor via a male joint and a female joint, and having a shaft on the side opposite to the motor, a driven gear meshing with the drive gear and connected to the steering means; A bearing member that supports the shaft portion and is movable in a direction in which the distance between the rotation centers of the drive gear and the driven gear becomes longer, a support member having a receiving hole for receiving the bearing member, and the drive gear as an anti-motor. In the electric power steering apparatus provided with urging means for urging to the side and assisting steering by rotation of the motor, at least one of the male joint part and the female joint part is a male joint part and a female joint part. An outflow stop ring is provided to prevent the lubricant filled between the shape joint portions from flowing out, and the male joint portion has a recess recessed in the axial length direction from the end surface, and the recess is provided with the recess. Energizing means is accommodated, and a plurality of the above-mentioned outflow stop rings are in the vicinity. Characterized in that juxtaposed so.
[0017]
  First2In the invention,Since the lubricant filled between the male joint and female joint can be prevented from flowing out from the opening end of the female joint, the tapping noise of the male joint and female joint can be reduced. It can be used over time while suppressing. Further, since the urging means is accommodated in the recess of the male joint portion, the urging means can be made smaller, and the area around the urging means can be made smaller, and the entire electric power steering apparatus can be made smaller. it can. Moreover,Since the lubricant can be prevented from flowing out from the opening end of the female joint part in two stages, the lubricant outflow prevention function of the outflow stop ring can be further enhanced.KiEven when the dynamic gear frequently oscillates due to the meshing reaction force, it is possible to prevent the lubricant from flowing out and to reduce the tapping noise of the male joint portion and the female joint portion.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
Embodiment 1
1 is an enlarged cross-sectional view of a reduction gear mechanism portion showing the configuration of Embodiment 1 of the electric power steering device according to the present invention, FIG. 2 is a cross-sectional view showing the configuration of the entire portion of the electric power steering device, and FIG. These are explanatory drawings which show the relationship between a drive gear and a driven gear, and the support hole of a support member.
[0019]
The electric power steering apparatus includes a steering assist motor 1, a worm 3 as a driving gear connected to the output shaft 1 a of the motor 1 via a shaft coupling 2, and a driven gear meshing with the worm 3. A reduction gear mechanism A having a worm wheel 4 and a steering means 5 having a rotating shaft (described later) for supporting the worm wheel 4 and connected to the worm wheel 4 are provided.
[0020]
The steering means 5 has one end connected to the steering wheel B for steering and a first steering shaft 51 having a cylindrical portion 51a at the other end, and is inserted into the cylindrical portion 51a, and one end thereof is the first. A torsion bar 52 that is connected to a cylindrical portion 51a of one steering shaft 51 and is twisted by the action of a steering torque applied to the steering wheel B, and the other end is connected to the other end of the torsion bar 52. The second steering shaft 53 is connected to a steering mechanism (not shown) of, for example, a rack and pinion type via a universal joint.
[0021]
The worm 3 of the reduction gear mechanism A has shaft portions 3 a and 3 b at both ends, and the output shaft of the motor 1 with the shaft portion 3 a at one end being rotatably supported by the support member 7 via the rolling bearing 6. The shaft portion 3 b at the other end is supported by the support member 7 via a cylindrical bearing member 8. The shaft portion 3 a is press-fitted into the inner ring 6 a of the rolling bearing 6. A regulating ring 9 such as a C-shaped ring as a fail sail that faces the one end of the inner ring 6a of the rolling bearing 6 and regulates the relative movement of the worm 3 with the inner ring 6a is detachably attached to the shaft portion 3a. . The worm wheel 4 is fitted and fixed in the middle of the rotating shaft 5.
[0022]
The support member 7 accommodates the worm 3, the first accommodating portion 7 a that rotatably supports the shaft portions 3 a and 3 b of the worm 3 via the rolling bearing 6 and the bearing member 8, and the worm wheel 4. It has the 2nd accommodating part 7b which supported this worm wheel 4 via the 2nd steering shaft 53 and the two rolling bearings 10 and 11 which were fitted by this 2nd steering shaft 53. As shown in FIG.
[0023]
The first accommodating portion 7a is elongated in the axial length direction of the worm 3, and at one end portion in the longitudinal direction, a support hole 71 that fits and supports the rolling bearing 6, a screw hole 72 that continues to the support hole 71, and a motor mounting portion. 73 is provided, and a screw ring 12 for fixing the rolling bearing 6 to the screw hole 72 is screwed. Further, the motor 1 is attached to the motor attachment portion 73.
[0024]
The second housing portion 7b is provided with two support holes 74 and 75 that fit and support the rolling bearings 10 and 11.
The center-to-center distance L between the center of the support hole 71 and the centers of the support holes 74 and 75 is obtained by adding φd / 2 of the pitch circle diameter φd of the worm 3 and φD / 2 of the pitch circle diameter φD of the worm wheel. It is set so as to be equal to or smaller than the dimension obtained by adding φd / 2 and φD / 2.
[0025]
Depending on the setting of this dimension, the worm 3 is substantially parallel to the parallel region (CC region in the figure) of the rotation center of the worm 3 and the worm wheel 4 with the support to the rolling bearing 6 as the center, or the rotation center. The distance H1 between the rotation centers on the shaft 3a side (motor side) is inclined with respect to the parallel region C-C so as to be shorter than the distance H2 between the rotation centers on the shaft 3b side (counter motor side).
[0026]
The output shaft 1a of the motor 1 and the shaft portion 3a of the worm 3 are joined via a male joint portion 21 and a female joint portion 22 having serrations. The male joint portion 21 is configured by providing serrations on the peripheral surface of the shaft portion 3a, and the female joint portion 22 is provided with serrations inside the cylindrical member 23 fitted and fixed to the output shaft 1a. The male joint portion 21 and the female joint portion 22 are serrated to form a radial clearance S1 between the male joint portion 21 and the female joint portion 22. A lubricant made of grease is filled between the male joint portion 21 and the female joint portion 22 by application.
[0027]
An annular groove 21a having a dimension equal to or smaller than the serration trough diameter is provided at the opposite end of the male joint portion 21 on the motor side, and the serration trough portion is provided at the open end of the female joint portion 22. An annular recess 22a having a dimension larger than the diameter is provided. An outflow stop ring 13 is fitted to the annular groove 21a to prevent the lubricant filled between the male joint portion 21 and the female joint portion 22 from coming into contact with the annular recess 22a. Is retained. The annular recess 22 a is provided from the opening edge of the female joint portion 22. Further, the annular recess 22 a may be formed in a groove shape in the vicinity of the edge of the female joint portion 22 on the opening side.
[0028]
A recess 21b that is recessed in the axial length direction is provided at the motor side end face of the male joint portion 21, in other words, at one end of the worm 3. The recess 21b accommodates a coil spring 14 as an urging means for urging the worm 3 toward the counter-motor side with one end abutting against the end surface of the output shaft 1a.
[0029]
The coil spring 14 is urged in parallel with the parallel region CC of the rotation center, and this urging force is at one end of the worm 3 with respect to the support portion center O of the shaft portion 3a to the rolling bearing 6. When the worm 3 is inclined with respect to the parallel region CC of the rotation center as described above, the worm 3 is swung in the direction in which the inclination angle becomes smaller. I am trying to make it. Further, the urging force of the coil spring 14 is transmitted from the shaft portion 3 a to the inner ring 6 a via the restriction ring 9, and the axial length clearance of the rolling bearing 6 is eliminated.
[0030]
FIG. 4 is an enlarged cross-sectional view showing the configuration of the outflow stop ring.
For example, as shown in FIGS. 4 (a) to 4 (e), the outflow stop ring 13 is made of rubber or the like having a flexible portion 13a whose axial length dimension is smaller than the radial dimension between the inner peripheral surface and the outer peripheral surface. Made of elastic material.
The outflow stop ring 13 of FIG. 4 (a) has a cross-sectional shape that is substantially elliptical in which the radial dimension is longer than the axial length dimension, and the inner periphery between the inner and outer peripheral surfaces and the radial center. The part and the outer part are set as the bending part 13a.
The outflow stop ring 13 in FIG. 4 (b) has a substantially X-shaped cross section having two contact ring portions 13b, 13b on the inner peripheral side and the outer peripheral side, and each contact ring portion 13b on the inner peripheral side and the outer peripheral side. Is the bending portion 13a.
The cross-sectional shape of the outflow stop ring 13 in FIG. 4 (c) is substantially E-shaped, and the central portion in the radial direction between the inner portion and the outer portion is a bending portion 13a.
4 (d) has a substantially U-shaped cross-section, in other words, an oil seal, and a central portion in the radial direction between the inner portion and the outer portion is a bending portion 13a.
4 (e) has a cross-sectional shape that is substantially Y-shaped with one contact ring portion 13c on the inner peripheral side and two contact ring portions 13c on the outer peripheral side. Each contact ring portion 13c on the outer peripheral side is a bending portion 13a.
[0031]
The other end portion of the first housing portion 7a faces the concave hole 76 into which the shaft portion 3b at the other end of the worm 3 is inserted and the inner surface of the concave hole 76, and is drilled toward the radial direction of the shaft portion 3b. In other words, a cylindrical accommodation hole 77 is provided that is drilled in the direction in which the worm 3 is pressed toward the worm wheel 4. A bearing member 8 in which the shaft portion 3 b is rotatably fitted in the accommodation hole 77, an elastic body 15 including a coil spring that urges the bearing member 8 in the pressing direction, and an outside of the accommodation hole 77. A closing member 15 that closes the opening is accommodated. Further, a threaded portion 78 is provided on the open side of the accommodation hole 77 to the outside, and the closed hole member 16 is screwed to the threaded portion 78.
[0032]
A gap S2 larger than the radial gap S1 is provided between the closed hole member 16 and the bearing member 8, and when the worm 3 moves in a direction in which the distance H2 between the rotation centers becomes longer due to a meshing reaction force or the like. The movement of the worm 3 is restricted by the radial gap S1 so that the bearing member 8 does not come into contact with the closed hole member 16.
[0033]
The bearing member 8 is provided with a bearing hole 8a drilled so as to be orthogonal to the moving direction in the middle of the axial direction, in other words, in the middle of the moving direction moving along the housing hole 77. A slide bearing 17 in which the shaft portion 3 b is rotatably fitted is inserted and fixed in the hole 8 a, and the shaft portion 3 b is supported by the bearing member 8 through the slide bearing 17.
[0034]
The support member 7 has a third housing portion 7c connected to the second housing portion 7b, and the steering torque applied to the steered wheels B by the relative rotational displacement amounts of the steering shafts 51 and 53 according to the torsion of the torsion bar 17. The torque sensor 18 is detected in the third storage portion 7c, and the motor 1 is configured to be driven and controlled based on the torque detected by the torque sensor 18.
[0035]
In the electric power steering apparatus configured as described above, when the motor 1 and the reduction gear mechanism A are incorporated, for example, in the state where the lubricant made of grease is filled in the female joint portion 22 by application, The male joint portion 21 is inserted into the female joint portion 22 of the output shaft 1a and is serrated. In this case, the outflow stop ring 13 provided at the end of the male joint 21 opposite to the motor contacts the annular recess 22a provided at the open end of the female joint 22, so the female joint 22 The internal lubricant can be prevented from flowing out from the open end of the female joint portion 22. Therefore, the male joint portion 21 and the female joint portion 22 can be used over time while suppressing the hitting sound.
[0036]
Further, when the female joint portion 22 of the output shaft 1a and the male joint portion 21 of the worm 3 are serrated, a radial clearance S1 is generated between the male joint portion 21 and the female joint portion 22. Further, the worm 3 supported by the rolling bearing 6 swings around the support portion (shaft portion 3a) to the rolling bearing 6 by the gap between the inner ring 6a and the outer ring 6b of the rolling bearing 6, and the worm 3 and the male The rotational center of the joint 21 can be inclined with respect to the center of the female joint 22 and the output shaft 1a within the range of the radial clearance S1.
[0037]
When the relationship between the distance L between the centers of the support hole 71 and the support holes 74 and 75 and the pitch circle diameter φd of the worm 3 and the pitch circle diameter φD of the worm wheel 4 is L <φd / 2 + φD / 2, The worm 3 is such that the distance H1 between the rotation centers on the motor side is shorter than the distance H2 between the rotation centers on the non-motor side with respect to the parallel region CC of the rotation center with the support portion to the rolling bearing 6 as the center. Tilt.
[0038]
The inclined worm 3 is biased in parallel with the parallel region CC of the rotation center by the coil spring 14 on the motor 1 side of the rolling bearing 6, so that the worm 3 is centered on the support portion for the rolling bearing 6. As shown in FIG. By this swinging, a preload can be applied to the meshing portion of the worm 3 and the worm wheel 4, and the backlash amount of the meshing portion can be reduced. Further, since the coil spring 14 biases the worm 3 on the side opposite to the motor 1 from the rolling bearing 6, the clearance in the axial length direction of the rolling bearing 6 is eliminated, and rattling in the axial length direction of the worm 3 is eliminated. be able to.
[0039]
When the relationship between the distance L between the centers of the support hole 71 and the support holes 74 and 75 and the pitch circle diameter φd of the worm 3 and the pitch circle diameter φD of the worm wheel 4 is L = φd / 2 + φD / 2, the worm 3 Is substantially parallel to the parallel region CC of the center of rotation. The worm 3 in the parallel state is biased in parallel with the parallel region CC of the center of rotation by the coil spring 14 on the motor 1 side of the rolling bearing 6, thereby reducing the backlash amount of the meshing portion. be able to. Further, since the coil spring 14 biases the worm 3 on the side opposite to the motor 1 from the rolling bearing 6, the clearance in the axial length direction of the rolling bearing 6 is eliminated, and rattling in the axial length direction of the worm 3 is eliminated. be able to.
[0040]
Further, in the case of assisting the steering by the rotation of the motor 1, when the worm 3 moves in the direction in which the distance H2 between the rotation centers becomes longer due to the meshing reaction force or the like, the peripheral surface of the male joint portion 21 becomes the female joint portion 22. It abuts and the movement of the worm 3 is restricted. In this case, since the gap S2 between the hole closing member 16 and the bearing member 8 is set larger than the radial gap S1, the bearing member 8 supporting the shaft portion 3b of the worm 3 contacts the hole closing member 16. The contact can be prevented, and the noise between the bearing member 8 and the closed hole member 16 can be eliminated. Since noise can be eliminated in this way, it is not necessary to provide a buffer member between the bearing member 8 and the closed hole member 16 as in Patent Document 1, and the number of parts can be reduced. Moreover, since the elastic body 15 which consists of a coil spring is interposed between the bearing member 8 and the closed hole member 16, the above-mentioned movement of the worm 3 can be suppressed, and the peripheral surface of the male joint part 21 is female. It is also possible to prevent contact with the joint portion 22. Further, in place of the elastic body 15, an urging means can be provided between the female joint portion 22 and the restriction ring 9.
[0041]
Further, as shown in FIG. 4, the outflow stop ring 13 has a bending portion 13 a whose axial length dimension is smaller than the radial dimension between the inner peripheral surface and the outer peripheral surface. Even when sufficiently secured, the lubricant can be prevented from flowing out, and the hitting sound of the male joint portion 21 and the female joint portion 22 can be reduced.
[0042]
In the embodiment described above, the gap S2 between the closed member 16 and the bearing member 8 is set to be larger than the radial gap S1, but otherwise, the radial gap S1 and the gap S2 are set to be equal. Alternatively, the gap S2 may be set to be smaller than the radial gap S1. In this case, sound generation between the bearing member 8 and the closed hole member 16 can be reduced by the elastic body 15 formed of a coil spring interposed between the bearing member 8 and the closed hole member 16.
[0043]
Embodiment 2
FIG. 5 is an enlarged cross-sectional view of a main part showing the configuration of the second embodiment of the electric power steering apparatus.
In the electric power steering device according to the second embodiment, the outflow stop ring 13 of FIG. 4 is juxtaposed at the opposite end of the male joint portion 21 on the motor side. In FIG. 5A, two annular grooves 21c and 21c that are separated in the axial length direction are provided, and an outflow stop ring 13 is inserted into each annular groove 21c. In FIG. 5 (b), an annular groove 21d having a width dimension into which two outflow stop rings 13 can be inserted is provided, and the two outflow stop rings 13 are inserted into the annular groove 21d.
[0044]
In the second embodiment, since the lubricant can be prevented from flowing out from the open end of the female joint portion 22 in two stages, the lubricant outflow prevention function of the outflow stop ring 13 can be further enhanced. it can. Therefore, even when the worm 3 frequently swings due to the meshing reaction force, the lubricant can be prevented from flowing out, and the tapping noise of the male joint portion 21 and the female joint portion 22 can be reduced.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.
[0045]
Embodiment 3
FIG. 6 is an enlarged cross-sectional view of a main part showing the configuration of Embodiment 3 of the electric power steering apparatus.
The electric power steering apparatus according to the third embodiment has a substantially disc spring shape that contacts the outflow stop ring 13 in FIG. 4 and one side of the outflow stop ring 13 at the opposite end of the male joint portion 21 on the motor side. The backup ring 19 is juxtaposed.
In the third embodiment, the outflow stop ring 13 and the backup ring 19 are inserted into one annular groove 21e.
[0046]
In the third embodiment, when the outflow stop ring 13 is bent due to the swing of the worm 3, the bending force of the outflow stop ring 13 is transmitted to the backup ring 19 and the backup ring 19 is also bent. The bending of the retaining ring 13 can be suppressed.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.
[0047]
Embodiment 4
FIG. 7 shows a configuration of an electric power steering apparatus according to a fourth embodiment. FIG. 7 (a) is an enlarged sectional view of a main part, and FIG. 7 (b) is a sectional view taken along line VII-VII in FIG.
In the electric power steering apparatus according to the fourth embodiment, instead of serration fitting the male joint portion 21 and the female joint portion 22, the male joint portion 21 and the female joint portion 22 are spline fitted to each other. An elastic ring 20 is provided between the motor-side end portion of the shape joint portion 21 and the female joint portion to suppress the peripheral surface of the male joint portion 21 from coming into contact with the female joint portion 22.
[0048]
In the fourth embodiment, the peripheral surfaces of the male joint portion 21 and the female joint portion 22 are provided with splines having a square cross-sectional shape. An annular recess 21f is provided at the motor side end of the male joint portion 21, and the elastic ring 20 is fitted and held in the annular recess 21f.
[0049]
In the fourth embodiment, since the side surfaces of the splines of the male joint portion 21 and the female joint portion 22 are orthogonal to the rotational direction of the output shaft 1a, the male joint portion 21 and the female joint portion. The strength of the 22 joining portions can be increased compared to serration.
Further, when the worm 3 swings around the support portion for the rolling bearing 6, it is possible to prevent the elastic ring 20 from being bent and the peripheral surface of the male joint portion 21 from coming into contact with the female joint portion 22, The noise generated between the male joint portion 21 and the female joint portion 22 can be reduced.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.
[0050]
Embodiment 5
FIGS. 8A and 8B show the configuration of the fifth embodiment of the electric power steering apparatus. FIG. 8A is an enlarged cross-sectional view of the main part, and FIG. 8B is a cross-sectional view taken along the line VIII-VIII of FIG.
In the electric power steering apparatus according to the fifth embodiment, instead of serration fitting and spline fitting between the male joint portion 21 and the female joint portion 22, the male joint portion 21 and the female joint portion 22 are interposed between them. An elastic ring 20 is provided that suppresses the circumferential surface of the male joint 21 from contacting the female joint 22 between the motor-side end of the male joint 21 and the female joint 22. It is provided.
[0051]
In the fifth embodiment, key grooves are provided at two positions separated in the circumferential direction on the peripheral surfaces of the male joint portion 21 and the female joint portion 22, and the key 30 is fitted in each key groove. Yes. An annular recess 21f is provided at the motor side end of the male joint 21, and the elastic ring 20 is fitted and held in the annular recess 21f.
[0052]
In the fifth embodiment, the relative rotation of the male joint portion 21 and the female joint portion 22 can be prevented by the key 30, and the rotation of the output shaft 1 a can be prevented from the female joint portion 22 via the key 30. Since it can transmit to the shape joint part 21, the intensity | strength of the joint part of the male shape joint part 21 and the female shape joint part 22 can be raised compared with a serration.
Further, when the worm 3 swings around the support portion for the rolling bearing 6, it is possible to prevent the elastic ring 20 from being bent and the peripheral surface of the male joint portion 21 from coming into contact with the female joint portion 22, The noise generated between the male joint portion 21 and the female joint portion 22 can be reduced.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.
[0053]
Embodiment 6
FIG. 9 is an enlarged cross-sectional view of a main part showing the configuration of the electric power steering apparatus according to the sixth embodiment.
In the electric power steering apparatus according to the sixth embodiment, a male joint portion 21 and a female joint portion 22 are joined together by an elastic body 31 having flexibility.
[0054]
In the sixth embodiment, the end face of the male joint portion 21 and the female joint portion 22 are provided with fitting holes 21g and 22b having a square cross section, and one end portion of the prismatic elastic body 31 is fitted to the fitting hole. 21g, the other end portion of the elastic body 31 is fitted into the fitting hole 22b, and the rotation of the output shaft 1a is transmitted from the female joint portion 22 to the male joint portion 21 via the elastic body 31. It is. Further, the end face of the male joint portion 21 and the opening end of the female joint portion 22 are spaced apart from each other by a size that allows the worm 3 to swing.
[0055]
In the sixth embodiment, the swing amount of the worm 3 can be sufficiently ensured, and noise from the joint portion of the male joint portion 21 and the female joint portion 22 can be eliminated. Furthermore, since the elastic body 31 can be twisted when transmitting the rotation of the output shaft 1a, the steering feeling can be improved.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.
[0056]
Embodiment 7
FIG. 10 is an enlarged cross-sectional view of the main part showing the configuration of the seventh embodiment of the electric power steering apparatus.
In the electric power steering apparatus according to the seventh embodiment, the male joint portion 21 and the female joint portion 22 are joined together by the elastic body 32 having flexibility, and further, the restriction for limiting the bending amount of the elastic body 32. A portion 21h is provided.
[0057]
In the seventh embodiment, the end of the male joint portion 21 on the motor side is connected to the cube-shaped fitting convex portion 21j and the fitting convex portion 21j, and is larger than the fitting convex portion 21j and has a cubic shape. The restricting portion 21h is provided, and the female joint portion 22 is provided with a fitting hole 22c that is larger than the restricting portion 21h and has a square cross section. The fitting hole 22c is longer than the fitting projection 21j.
[0058]
The elastic body 32 is formed of a ring member having a square cross section, and the inside of the elastic body 32 is fitted to the fitting convex portion 21j. The male joint portion 21 and the female joint portion 22 are joined by the elastic body 32 by fitting the fitting hole 22 c to the outside of the elastic body 32.
[0059]
In the seventh embodiment, it is possible to ensure a sufficient amount of swing of the worm 3 and to eliminate noise at the joint portion of the male joint portion 21 and the female joint portion 22. Furthermore, when the elastic body 32 bends to a certain amount or more due to the swing of the worm 3, the opening end portion of the female joint portion 22 comes into contact with the limiting portion 21h, and the bending amount of the elastic body 32 can be limited. Therefore, damage to the elastic body 32 can be prevented. Further, since the elastic body 32 can be twisted when transmitting the rotation of the output shaft 1a, the steering feeling can be improved.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.
[0060]
Embodiment 8
FIG. 11 is an enlarged cross-sectional view of a main part showing the configuration of the eighth embodiment of the electric power steering apparatus.
In the electric power steering apparatus according to the eighth embodiment, the elastic body 31 according to the sixth embodiment biases the worm 3 toward the non-motor side.
[0061]
In the eighth embodiment, the end face of the male joint portion 21 and the open end of the female joint portion 22 are separated by a dimension that is larger than the distance at which the elastic body 31 can be bent in the axial length direction. When the male joint portion 21 and the female joint portion 22 are joined via the body 31, the elastic body 31 is bent in the axial length direction.
[0062]
In the eighth embodiment, since the transmission elastic body 31 also serves as an urging spring, the number of parts can be reduced.
Since other configurations and operations are the same as those of the first and sixth embodiments, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.
[0063]
Embodiment 9
FIG. 12 is an enlarged cross-sectional view of a main part showing the configuration of the ninth embodiment of the electric power steering apparatus.
In the electric power steering apparatus according to the ninth embodiment, the worm 3 is moved between the end surface of the male joint portion 21 and the open end of the female joint portion 22 around the elastic body 31 of the sixth embodiment. A coil spring 33 is provided to bias the side.
[0064]
In the ninth embodiment, the end face of the male joint portion 21 and the open end of the female joint portion 22 are separated by a dimension that allows the coil spring 33 to be interposed therebetween.
Since other configurations and operations are the same as those of the first and sixth embodiments, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.
[0065]
In the embodiment described above, the output shaft 1a of the motor 1 has the female joint portion 22 and the shaft portion 3a of the worm 3 has the male joint portion 21. It is good also as a structure which has the male joint part 21 and the shaft part 3a has the female joint part 22. FIG.
Further, the reduction gear mechanism A of the embodiment described above may be a bevel gear in addition to a worm gear provided with a drive gear that is a worm 3 and a driven gear that is a worm wheel 4.
[0066]
【The invention's effect】
  As described above in detail, according to the first invention, it is possible to prevent the lubricant filled between the male joint portion and the female joint portion from flowing out from the open end of the female joint portion. It can be used over time while suppressing the hitting sound of the shape joint portion and the female shape joint portion.Moreover, even when the drive gear capable of sufficiently securing the adjustment amount of the backlash amount of the meshing portion frequently swings due to the meshing reaction force, the lubricant can be prevented from flowing out, and the male joint portion In addition, the hitting sound of the female joint can be reduced. In addition, the urging means can be reduced in size, the area around the urging means can be reduced in size, and the entire electric power steering apparatus can be reduced in size.
[0068]
  First2According to the invention,Lubricant filled between the male joint and female joint can be prevented from flowing out from the open end of the female joint, and the tapping noise of the male joint and female joint can be suppressed. However, it can be used over time. Moreover,Even when the drive gear capable of sufficiently securing the adjustment amount of the backlash amount of the meshing portion frequently swings due to the meshing reaction force, the lubricant can be prevented from flowing out, and the male joint portion and the female joint portion can be prevented. The hitting sound of the joint can be reduced.In addition, the urging means can be reduced in size, the area around the urging means can be reduced in size, and the entire electric power steering apparatus can be reduced in size.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view of a reduction gear mechanism portion showing the configuration of a first embodiment of an electric power steering apparatus according to the present invention.
FIG. 2 is a cross-sectional view showing the configuration of the entire part of the electric power steering apparatus according to the present invention.
FIG. 3 is an explanatory view showing a relationship between a drive gear and a driven gear of the electric power steering apparatus according to the present invention and a support hole of a support member.
FIG. 4 is an enlarged sectional view showing a configuration of an outflow stop ring of the electric power steering apparatus according to the present invention.
FIG. 5 is an enlarged cross-sectional view of a main part showing the configuration of Embodiment 2 of the electric power steering apparatus according to the present invention.
FIG. 6 is an enlarged cross-sectional view of a main part showing the configuration of Embodiment 3 of the electric power steering apparatus according to the present invention.
7 shows the configuration of Embodiment 4 of the electric power steering apparatus according to the present invention, where (a) is an enlarged cross-sectional view of the main part, and (b) is a cross-sectional view taken along line VII-VII of (a) FIG.
8 shows the configuration of Embodiment 5 of the electric power steering apparatus according to the present invention, where (a) is an enlarged cross-sectional view of the main part, and (b) is a cross-sectional view taken along line VIII-VIII of (a). FIG.
FIG. 9 is an enlarged cross-sectional view of a main part showing the configuration of Embodiment 6 of the electric power steering apparatus according to the present invention.
FIG. 10 is an enlarged cross-sectional view of a main part showing the configuration of an electric power steering apparatus according to Embodiment 7 of the present invention.
FIG. 11 is an enlarged cross-sectional view of a main part showing a configuration of an electric power steering apparatus according to an eighth embodiment of the present invention.
FIG. 12 is an enlarged cross-sectional view of a main part showing a configuration of an electric power steering apparatus according to Embodiment 9 of the present invention.
[Explanation of symbols]
1 Motor
1a Output shaft
3 Worm (drive gear)
3b Shaft
4 Worm wheel (driven gear)
5 Steering means
7 Support members
77 receiving hole
8 Bearing members
21 Male fitting
21b recess
22 Female joint
13 Outflow ring
13a flexible part
14 Coil spring (biasing means)

Claims

A drive gear joined to the output shaft of the motor via a male joint and a female joint, and having a shaft on the side opposite to the motor, a driven gear meshing with the drive gear and connected to the steering means; A bearing member that supports the shaft portion and is movable in a direction in which the distance between the rotation centers of the drive gear and the driven gear becomes longer, a support member having a receiving hole for receiving the bearing member, and the drive gear as an anti-motor. In the electric power steering apparatus provided with urging means for urging to the side and assisting steering by rotation of the motor, at least one of the male joint part and the female joint part is a male joint part and a female joint part. An outflow stop ring is provided to prevent the lubricant filled between the shape joint portions from flowing out, and the male joint portion has a recess recessed in the axial length direction from the end surface, and the recess is provided with the recess. Urging means is accommodated, and the outflow stop ring has an inner peripheral surface and Between the outer peripheral surface, an electric power steering apparatus size in the axial direction and having a smaller bending portion than the dimension in the radial direction.

A drive gear joined to the output shaft of the motor via a male joint and a female joint, and having a shaft on the side opposite to the motor, a driven gear meshing with the drive gear and connected to the steering means; A bearing member that supports the shaft portion and is movable in a direction in which the distance between the rotation centers of the drive gear and the driven gear becomes longer, a support member having a receiving hole for receiving the bearing member, and the drive gear as an anti-motor. In the electric power steering apparatus provided with urging means for urging to the side and assisting steering by rotation of the motor, at least one of the male joint part and the female joint part is a male joint part and a female joint part. An outflow stop ring is provided to prevent the lubricant filled between the shape joint portions from flowing out, and the male joint portion has a recess recessed in the axial length direction from the end surface, and the recess is provided with the recess. Energizing means is accommodated, and a plurality of the above-mentioned outflow stop rings are in the vicinity. That are juxtaposed so that the electric power steering apparatus according to claim.