JP3748700B2

JP3748700B2 - Rack and pinion type steering device and boot used therefor

Info

Publication number: JP3748700B2
Application number: JP02626298A
Authority: JP
Inventors: 昇源
Original assignee: Koyo Seiko Co Ltd
Current assignee: Koyo Seiko Co Ltd
Priority date: 1998-02-06
Filing date: 1998-02-06
Publication date: 2006-02-22
Anticipated expiration: 2018-02-06
Also published as: JPH11222145A

Description

【０００１】
【発明の属する技術分野】
本発明は、舵取り操作に応じて回転するピニオン軸のピニオンと噛合するラック歯が設けられ、車体の左右方向へ移動するラック軸の中途部にタイロッド取付体を取付けてなるラックピニオン式舵取装置及びこれに用いるブーツに関する。
【０００２】
【従来の技術】
自動車用の舵取装置の一形式として、舵輪（ステアリングホイール）に連動連結されたピニオン軸のピニオンを車体の左右方向に延設されたラック軸のラック歯に噛合させてなり、舵取りのための舵輪の回転操作をラック軸の軸長方向の移動に変換し、この移動を一対のタイロッドから左右の操向車輪（一般的には前輪）に伝えて舵取りを行わせる構成としたラックピニオン式舵取装置がある。
【０００３】
このようなラックピニオン式舵取装置は、更に、左右の操向車輪との連結のための前記タイロッドをラック軸の両端部に各別に取付けてなるエンドテイクオフ形と、前記タイロッドをラック軸の中途部に一つのタイロッド取付体を介して取付けてなるセンタテイクオフ形とに大別される。
【０００４】
センタテイクオフ形のラックピニオン式舵取装置は、左右の操向車輪に至るタイロッドが長寸となる反面、これらと操向車輪との相対的な位置関係の設定に自由度が大きいという利点を有しており、一部の車種において採用されている。
【０００５】
ブーツは、前記ラック軸の周りに両端部が封止されるように配置され、伸縮が可能なブーツ本体の中間部に、前記ラック軸の軸長方向と交叉する突起を有する前記タイロッド取付体の前記突起が嵌合される嵌合部を設けてなり、ラック軸周りにゴミ、水などの異物が入るのを防ぐものである。
【０００６】
タイロッド取付体のラック軸への取付けは、実開昭５７−１７４２７５号公報、米国特許第４，６０１，６０２号等に開示されている如く、タイロッド取付体の突起をブーツの嵌合部に嵌合し、前記突起を貫通するねじ体を、ラック軸に設けられた取付孔に緊締することにより取付け、タイロッド取付体をブーツの外側に配置することにより実現されている。
【０００７】
前記突起の外周面は、上記米国特許第４，６０１，６０２号に記載されているものを図１０に示すように、基端から先端に向かって小径となるテーパ面に形成され、この突起Ａのテーパ面の中途に環状溝Ｂが設けられている。そして、ブーツＣの嵌合部は貫通している。この貫通孔Ｄは、前記突起Ａの外形よりも小径に形成され、該貫通孔Ｄを突起Ａの先端から環状溝Ｂへと無理やり押し込むことにより、該貫通孔Ｄを環状溝Ｂに嵌合し、ブーツＣの突起Ａが嵌合される嵌合部の封止性を高め、該嵌合部からブーツＣ内にゴミ、水などの異物が入るのを防ぐようにしている。
【０００８】
【発明が解決しようとする課題】
ところが、上述のラックピニオン式舵取装置にあっては、ブーツＣの貫通孔Ｄを突起Ａの先端から環状溝Ｂへと無理やり押し込み、該貫通孔Ｄを環状溝Ｂに嵌合することにより、ブーツＣの嵌合部の封止性を高め、タイロッド取付体Ｅをラック軸Ｆに取付けるように構成されているから、ブーツＣの突起Ａへの嵌め込みが非常に困難である。従って、タイロッド取付体Ｅの取付け作業性が悪く、コスト高になるという問題があった。
【０００９】
このような問題点に対し本発明出願人は、前記突起が嵌合されるブーツの嵌合部を、前記突起の外形に対応する嵌合内面が設けられた筒状に形成して、ブーツの嵌合部の突起への嵌め込みを容易に行うことができ、しかも、この嵌め込みにより嵌合部の封止性を高めることができるようにしたラックピニオン式舵取装置を先に出願した。
【００１０】
ところが、このラックピニオン式舵取装置によると、ラック軸の往復移動に追従してブーツの前記嵌合部に対する長手方向一方側及び他方側が縮小／伸長するときの前記嵌合部の封止性に改善の余地があった。
【００１１】
本発明は斯かる事情に鑑みてなされたものであり、ブーツの前記嵌合内面に周方向に延びる突条を設けることにより、ラック軸の移動に追従してブーツが伸縮する場合の嵌合部の封止性を高めることができて、しかも、タイロッド取付体の取付作業性を高めることができるラックピニオン式舵取装置及びこれに用いるブーツを構成することを目的とする。
【００１２】
【課題を解決するための手段】
第１発明に係るラックピニオン式舵取装置は、舵取り操作に応じて回転するピニオン軸のピニオンと噛合するラック歯が設けられ、車体の左右方向へ移動するラック軸に、該ラック軸の軸長方向と交叉する突起を有するタイロッド取付体が前記突起を貫通して前記ラック軸に緊締されるねじ体により取付けられており、前記ラック軸の周りに両端部が封止されるように配置され、前記突起が嵌合される嵌合部を有する伸縮が可能なブーツを設けてなるラックピニオン式舵取装置において、前記突起は、基端から先端に向かって小径となるテーパ状に形成されており、前記嵌合部は、前記突起の外形に対応させて基端から先端に向かって小径となるテーパ状に形成された嵌合内面を有し、且つ弾性変形が可能な筒状であり、該嵌合内面に周方向に延び、且つ前記突起の外面と接触する突条が設けられており、前記突起が前記嵌合部に嵌合するとき該嵌合部が弾性変形し、該嵌合部の弾性復元力により前記嵌合内面が前記突起の外面に接触するように構成してあることを特徴とする。
【００１３】
第４発明に係るブーツは、舵取り操作に応じて移動するラック軸の周りに両端部が封止されるように配置され、伸縮が可能なブーツ本体の中間部に、前記ラック軸の軸長方向と交叉する方向に突設され、且つ基端から先端に向かって小径となるテーパ状に形成された突起を有するタイロッド取付体の前記突起が嵌合される嵌合部を設けてなるブーツにおいて、前記嵌合部は、基端から先端に向かって小径となるテーパ状に形成された嵌合内面を有し、且つ弾性変形が可能な筒状であり、該嵌合内面に周方向に延び、且つ前記突起の外面と接触すべき突条が設けられており、前記突起が前記嵌合部に嵌合するとき該嵌合部が弾性変形し、該嵌合部の弾性復元力により前記嵌合内面が前記突起の外面に接触するように構成してあることを特徴とする。
【００１４】
第１発明及び第４発明にあっては、ブーツの嵌合部を突起に嵌め込むことにより、突起の外形に対応する嵌合内面、及び該嵌合内面に設けた突条が突起の外面と接触し、これら嵌合内面及び突条により封止することができるから、ラック軸の移動に追従してブーツが伸縮する場合の嵌合部の封止性を高めることができる。また、嵌合部は、嵌合内面が設けられた筒状に形成しているから、嵌合部の突起への嵌め込みを容易に行うことができ、タイロッド取付体の取付作業を簡易に行うことができる。
【００１５】
第２発明に係るラックピニオン式舵取装置は、前記突条が、前記突起との接触により撓むようにしてあることを特徴とする。
第３発明に係るラックピニオン式舵取装置は、前記突起及び嵌合部は前記ラック軸の軸長方向に離隔した二箇所に設けてあり、前記突条は各嵌合部の嵌合内面の周方向位置で、且つ前記ラック軸の移動時に前記ブーツが伸長する側に設けてあることを特徴とする。
【００１６】
第２発明にあっては、ブーツの嵌合部を突起に嵌め込むことにより、突条が突起の外面と接触して撓むとともに、嵌合内面が突起の外面と接触することになるから、ラック軸の移動に追従して移動するブーツの嵌合部に対する長手方向一方側及び他方側の伸縮量が所定量以上になって、嵌合内面の一部が突起と接触しない状態となる場合、嵌合内面に設けた突条が弾性復帰して突起との接触状態を良好に保つことができ、嵌合部の封止性をより一層高めることができる。
【００１７】
【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。図１は本発明に係るラックピニオン式舵取装置の要部の構成を示す縦断正面図、図２は要部の構成をさらに拡大した断面図、図３は要部の構成を分解した縦断面図、図４はブーツを示すもので、(a) は一部を省略した断面図、(b) は底面図、(c) は縦断側面図、図５はラック軸の底面図、図６はラックピニオン式舵取装置全体の断面図である。
【００１８】
図６に示したラックピニオン式舵取装置は、一端部が舵輪（ステアリングホイール）に連動連結され、他端部にピニオン（図示せず）が設けられたピニオン軸１と、前記ピニオンに噛合するラック歯（図示せず）が設けられ、車体の左右方向に延設されたラック軸２と、該ラック軸２の周りに配置される円筒状の伸縮が可能なブーツ３と、これらラック軸２及びブーツ３間に介在されてラック軸２及びブーツ３を支持するラックハウジング４と、一対のタイロッド５，５の基端部を保持する一つのタイロッド取付体６と、該タイロッド取付体６を、前記ブーツ３及びラックハウジング４を貫通してラック軸２の中途部に取付けるねじ体７，７とを備えたセンタテイクオフ形のラックピニオン式舵取装置である。
【００１９】
ラック軸２は、図６に示すように、一端部が閉止された円筒形をなす前記ラックハウジング４の内部に軸長方向への摺動が自在に支承されている。また、ラック軸２の一端部には、前記タイロッド取付体６を取付けるための一対の取付孔２１，２１が軸長方向に所定間隔を隔てて穿設されている。これら取付孔２１，２１は、図１に示すように、ラック軸２の軸長方向と交叉するように傾斜しており、その開口部に、平坦状の受座２２，２２が設けられている。
【００２０】
ラックハウジング４は、図６に示すように、一端が閉止され、他端が開放された有底筒状に形成され、その閉止側の中途部には、これと交叉する態様にピニオンハウジング８が連設してあり、該ピニオンハウジング８の内部には、軸心回りでの回転自在に前記ピニオン軸１が支承され、該ピニオン軸１の回転がラック軸２の軸長方向の摺動に変換されるようになしてある。
【００２１】
ラックハウジング４の開放側の中途部には、図６に示すように、前記タイロッド取付体６をラックハウジング４に対し移動させるための窓孔４１を設け、該窓孔４１の形成域周りを前記ブーツ３により覆い、ゴミ、水などの異物が窓孔４１からラックハウジング４内に侵入するのを防止するようにしている。
【００２２】
タイロッド取付体６は、図１に示すように、タイロッド５の基端部を挾持する一対の挾持片６１，６２と、これら挾持片６１，６２の一端を連結する連結片６３と、一方の挾持片６１に所定間隔を隔てて固着され、ラック軸の軸長方向と交叉する一対の筒状の突起６４，６４とを備え、これら突起６４，６４の中心部孔に対応する貫通孔６５が各挾持片６１，６２に穿設されている。そして、これら貫通孔６５及び突起６４の中心部孔に前記ねじ体７を挿通して、該ねじ体を前記ラック軸の取付孔に緊締することにより、突起をラック軸の受座２２，２２に当接させ、タイロッド取付体をブーツの外側に配置している。
【００２３】
ブーツ３は、可撓性を有する合成樹脂、ゴムなどにより筒状に形成されるもので、図４に示すように、両端部を蛇腹形状とした伸縮部３１，３１、及びこれら伸縮部３１，３１を連結する連結筒部３２を有するブーツ本体３０を備え、前記連結筒部３２に、前記タイロッド取付体６と対向する扁平部３３を設けている。また、伸縮部３１，３１の両端は、取付環９，９によりラックハウジング４に着脱可能に取付けられている。
【００２４】
扁平部３３には、図４（ａ）に示すように、前記突起６４，６４が嵌合される嵌合部３４，３４が設けられている。この嵌合部３４，３４は、前記突起６４，６４の外形に対応する嵌合内面３４ａ，３４ａが設けられており、弾性変形が可能な筒状に形成している。即ち、突起６４，６４と同様、基端から先端に向かって小径となるテーパ状に形成して、嵌合内面３４ａ，３４ａを突起６４，６４の外面に密着状に接触させて、嵌合部３４，３４の封止性を高めることができるようにしている。そして、該嵌合部３４，３４及び前記突起６４，６４を、図１に示すように、基端から先端に向かって離反するように傾斜させている。
【００２５】
実施の形態１の前記嵌合部３４，３４の嵌合内面３４ａ，３４ａには、周方向に連続しており、前記突起６４，６４の外面と接触する突条３５，３５を設けて、これら嵌合内面３４ａ，３４ａ及び突条３５，３５の突起６４，６４との接触により封止するようにしている。
【００２６】
この場合、図２に示す如く突条３５，３５が突起６４，６４の外面と接触して嵌合部３４，３４が押し広げられるように弾性変形するとともに、この嵌合部３４，３４の弾性復元力により嵌合内面３５ａ，３５ａが突起６４，６４の外面と接触することになる。このように突条３５，３５を設けた場合、嵌合部３４，３４の弾性復元力を、突条３５，３５を設けない場合に比べて大きくすることができる。
【００２７】
突条３５，３５は、図３、図４に示す如く嵌合部３４，３４の長手方向に所定間隔を隔てて複数個設けるのであるが、一個でもよい。また、周方向に連続して設ける他、ラック軸２の移動時に伸長する側、即ち、図１においては左側の嵌合部３４に対し左側部分、右側の嵌合部３４に対し右側部分にのみ設けてもよい。この場合の突条３５，３５は、両端に向かって漸次突出高さが低くなり、嵌合内面３４ａ，３４ａとの間に段差が生じないようにするのが好ましい。
【００２８】
図１〜図４に示した前記嵌合部３４，３４は、先端部から径方向内側へ突出する鍔３６，３６を突設して、ブーツ３の嵌合部３４，３４を突起６４，６４に嵌合した状態でねじ体７，７を緊締することにより、鍔３６，３６を、前記突起６４，６４の先端面とラック軸２の受座２２，２２との間で挾圧し、該鍔３６，３６を弾性変形させ、嵌合部３４，３４の封止性をより一層高めることができるようにしている。
【００２９】
また、前記ラック軸２の受座２２，２２に、前記鍔３６，３６の厚さよりも若干短い突部２３，２３を設けて、ねじ体７，７を取付孔２１，２１に緊締した場合、突起６４，６４を突部２３，２３で受止め、前記鍔３６，３６に過大の挾圧力が作用するのを回避し、鍔３６，３６の挾圧力による破損を防止するようにしている。
【００３０】
尚、図において１０はラック軸２の取付孔２１，２１間の外周面に嵌合され、ラックハウジング４の内周面に接触する略Ｃ字形の滑り軸受、１１は該滑り軸受１０を固定するピン、１２は滑り軸受１０の内側のラック軸２に設けるシールリングである。
【００３１】
また、図６に示した実施の形態のラックピニオン式舵取装置は、ラック軸２の摺動を油圧により補助する動力舵取装置として構成されており、ラック軸２に補助力を加える油圧シリンダ１３は、ラック軸２の一端に同軸をなして連結されたピストンロッド１４を、ラックハウジング４の開放端部に連設されたシリンダチューブ１５内に延設し、この延設端に取付けたピストン１６を、その外周に巻装されたシールリング１７を介してシリンダチューブ１５摺動自在に内嵌せしめて構成されている。
【００３２】
シリンダチューブ１５は、ラックハウジング４との連結端の逆側を閉止してなる有底円筒形の部材であり、ラックハウジング４との連結側には、その内側にシール部材１８を保持するシールホルダ１９が取付けてある。ピストンロッド１４は、前記シール部材１８によりその中途部を液密に封止してシリンダチューブ１５の内部に延設してある。
【００３３】
以上の如く油圧シリンダ１３は、ピストン１６の両側にて液密に封止された一対の油室をシリンダチューブ１５の内側に形成してなり、これらの油室への外部からの油圧送給に応じてピストン１６の両側に発生する圧力差により前記ピストンロッド１４を軸長方向に押し引きし、該ピストンロッド１４の基端に連結された前記ラック軸２に軸長方向の移動力を加える構成となっている。
【００３４】
ピストン１６両側の油室は、シリンダチューブ１５の外側の該当位置に夫々接続された各別の送油管２０，２０により、前記ピニオンハウジング８の外側に設けられた一対の送油ポート８１，８２に接続されている。該ピニオンハウジング８には、舵取りのための舵輪操作に伴って前記ピニオン軸１に加わる操舵トルクに応じて油圧の給排動作を行い、前記送油ポート８１，８２のいずれかに送出する公知の油圧制御弁が内蔵されており、送油ポート８１，８２への送出油圧が送油管２０，２０を経て油圧シリンダ１３に送給され、この送給に応じて発生する油圧力がラック軸２に加えられ、前述の如く生じる舵取りが補助される構成となっている。
【００３５】
以上の如く構成されたセンタテイクオフ形のラックピニオン式舵取装置のタイロッド５，５をラック軸２に取付ける場合、タイロッド５，５の基端部をタイロッド取付体６の挾持片６１，６２間に介在させ、これら挾持片６１，６２の貫通孔６５、タイロッド５の基端部の貫通孔５１及び突起６４，６４の中心部孔にねじ体７，７を挿通した状態で、突起６４，６４をブーツ３の嵌合部３４，３４に嵌合し、この状態でねじ体７，７をラック軸２の取付孔２１，２１に緊締することにより、嵌合部３４，３４を押し広げるように弾性変形させることができ、この嵌合部３４，３４の弾性復元力により嵌合内面３４ａ，３４ａ及び突条３５，３５を突起６４，６４の外面に接触させることができる。
【００３６】
また、舵輪の回転操作によりピニオン軸１を介してラック軸２が軸長方向へ往復移動した場合、該ラック軸２に取付けられたタイロッド取付体６を介してブーツ３がラック軸２の移動に追従して往復移動する。
【００３７】
このラック軸２の往移動により、例えばブーツ３の嵌合部３４，３４に対する長手方向一方側（図１の左側）の伸縮部３１が縮小し、他方側（図１の右側）が伸長することになり、また、ラック軸２の復移動により、ブーツ３の嵌合部３４，３４に対する長手方向他方側（図１の右側）の伸縮部３１が縮小し、一方側（図１の左側）が伸長することになる。
【００３８】
このようにブーツ３の嵌合部３４，３４に対する長手方向一方側又は他方側が伸長する場合、伸長側の嵌合部３４に伸縮部３１の伸長力が作用して嵌合内面３４ａの一部が突起６４と接触しない状態となる。
【００３９】
しかし、実施の形態１では、嵌合部３４，３４の嵌合内面３４ａ，３４ａに突条３５，３５を設けて、これら嵌合内面３４ａ，３４ａ及び突条３５，３５を突起６４，６４の外面に接触させるようにしており、また、突条３５，３５を設けた場合、嵌合部３４，３４の弾性復元力を、突条３５，３５を設けない場合に比べて大きくすることができるから、ラック軸２の移動に追従してブーツ３が移動することにより、嵌合内面３４ａの一部が突起６４と接触しない状態となるものの、嵌合部３４の弾性復元力により突条３５の突起との接触状態を良好に保つことができる。従って、嵌合部３４，３４の封止性を良好に高めることができる。
【００４０】
しかも、前記した従来例のように、予めタイロッド取付体６をブーツ３に取付けることなく、換言すると、突起６４，６４の外面に環状溝を設け、該環状溝にブーツ３の嵌合部を無理やり押し込んで取付ける必要がなく、単に嵌合部３４，３４を突起６４，６４に嵌合してねじ体７，７を緊締するだけの簡単な作業により、タイロッド取付体６の固定に影響を及ぼすことなくブーツ３の嵌合部３４，３４の封止性を高めることができる。
【００４１】
そして、前記タイロッド５，５は、タイロッド取付体６を介してブーツ３と共にラック軸２に取付けられることになり、前記窓孔４１の形成範囲内にて生じるラック軸２の両方向の摺動は、前記連結筒部３２の両側の伸縮部３１，３１の伸縮によって許容される。
【００４２】
以上説明した実施の形態１の突条３５は、嵌合部３４，３４を突起６４，６４に嵌め込み、ねじ体７，７を緊締したとき、弾性変形により撓んで嵌合内面と重なるように形成してもよい。この実施の形態の場合、その他の構成は実施の形態１と同様であるため、詳細な説明を省略する。斯く構成することにより、ラック軸２の移動に追従して移動するブーツ３の嵌合部３４，３４に対する長手方向一方側及び他方側の伸縮量が所定量以上になって、嵌合内面３４ａ，３４ａの一部が突起６４，６４と接触しない状態となる場合、突条３５，３５が弾性復帰して突起６４，６４との接触状態を良好に保つことができるから、ブーツ３の前記伸縮量が所定量以上になった場合の封止性をより一層高めることができる。
【００４３】
また、実施の形態１の嵌合部３４，３４は、先端部の鍔３６，３６をなくして、図７に示す如く少なくとも先端部分を前記突起６４，６４の外形よりも小径に形成し、前記突起６４，６４に嵌合により先端部分を押し広げるように弾性変形させるときの弾性復元力を大きくするように構成してもよい。この実施の形態の場合、その他の構成は実施の形態１と同様であるため、詳細な説明を省略する。斯く構成することにより、実施の形態１と同様、嵌合部３４，３４の封止性を良好に高めることができる。尚、この実施の形態においても突条３５を、前記したように弾性変形により撓んで嵌合内面と重なるように形成してもよい。
【００４４】
尚、以上説明した実施の形態では、２本のねじ体７，７を用いてタイロッド取付体６をラック軸２に取付ける構造のものについて説明したが、その他、タイロッド取付体６のラック軸２への取付けは、図８に示すように１本のねじ体７を用いて行ってもよい。
【００４５】
またタイロッド取付体６をラック軸２に取付けるためのねじ体７，７は、図１及び図６に示すように、ラック軸２の軸長方向と交差するように傾斜させた構成とする他、図９に示すようにラック軸２の軸長方向とほゞ直交する構成としてもよいのである。これら図８及び図９の実施の形態は、基本的に図１〜図７に示す実施の形態と同様であるため、共通の符号を用い、詳細な説明を省略する。
【００４６】
【発明の効果】
以上詳述した如く第１発明及び第４発明によれば、突起の外形に対応する嵌合内面、及び該嵌合内面に設けた突条を突起の外面と接触させて、これら嵌合内面及び突条により封止することができるから、ラック軸の移動に追従してブーツが伸縮する場合の嵌合部の封止性を良好に高めることができる。しかも、筒状の嵌合内面を突起に嵌め込むことにより封止することができるから、タイロッド取付体の取付作業を簡易に行うことができ、コストを低減できる。
【００４７】
第２発明によれば、ラック軸の移動に追従して移動するブーツの嵌合部に対する長手方向一方側及び他方側の伸縮量が所定量以上になって、嵌合内面の一部が突起と接触しない状態となる場合、嵌合内面に設けた突条が弾性復帰して突起との接触状態を良好に保つことができるから、嵌合部の封止性をより一層高めることができる。
【図面の簡単な説明】
【図１】本発明に係るラックピニオン式舵取装置の要部の構成を示す縦断正面図である。
【図２】本発明に係るラックピニオン式舵取装置の要部の構成をさらに拡大した断面図である。
【図３】本発明に係るラックピニオン式舵取装置の要部の構成を分解した縦断面図である。
【図４】本発明に係るブーツを示すもので、(a) は一部を省略した断面図、(b) は底面図、(c) は縦断側面図である。
【図５】本発明に係るラックピニオン式舵取装置のラック軸の底面図である。
【図６】本発明に係るラックピニオン式舵取装置の全体の断面図である。
【図７】本発明に係るラックピニオン式舵取装置の別の実施の形態を拡大した断面図である。
【図８】本発明に係るラックピニオン式舵取装置の別の実施の形態を示す要部の断面図である。
【図９】本発明に係るラックピニオン式舵取装置の別の実施の形態を示す要部の断面図である。
【図１０】従来例を示すラックピニオン式舵取装置の断面図である。
【符号の説明】
２ラック軸
３ブーツ
３４嵌合部
３４ａ嵌合内面
３５突条
６タイロッド取付体
６４突起
７ねじ体[0001]
BACKGROUND OF THE INVENTION
The present invention provides a rack and pinion type steering device in which rack teeth that mesh with a pinion of a pinion shaft that rotates in response to a steering operation are provided, and a tie rod mounting body is attached to a middle portion of the rack shaft that moves in the left-right direction of the vehicle body And a boot used therefor.
[0002]
[Prior art]
As one type of steering device for automobiles, the pinion of the pinion shaft linked to the steering wheel (steering wheel) is meshed with the rack teeth of the rack shaft extending in the left-right direction of the vehicle body, for steering A rack and pinion type rudder that converts steering operation of the steering wheel into movement in the axial direction of the rack shaft and transmits this movement from the pair of tie rods to the left and right steering wheels (generally the front wheels) to steer. There is a take-out device.
[0003]
Such a rack and pinion type steering device further includes an end take-off type in which the tie rods for connection to the left and right steering wheels are separately attached to both ends of the rack shaft, and the tie rods are disposed in the middle of the rack shaft. It is roughly divided into a center take-off type that is attached to the part via one tie rod attachment body.
[0004]
The center take-off type rack and pinion type steering device has the advantage that the tie rods leading to the left and right steered wheels are long, but has a high degree of freedom in setting the relative positional relationship between these and the steered wheels. It is used in some car models.
[0005]
The boot is arranged so that both ends thereof are sealed around the rack shaft, and the tie rod attachment body has a protrusion intersecting with the axial direction of the rack shaft at an intermediate portion of the boot body capable of expansion and contraction. A fitting portion to which the projection is fitted is provided to prevent foreign matters such as dust and water from entering around the rack shaft.
[0006]
As shown in Japanese Utility Model Laid-Open No. 57-174275, US Pat. No. 4,601,602, etc., the tie rod mounting body is mounted on the rack shaft. In addition, the screw body penetrating the protrusion is attached by tightening it in an attachment hole provided in the rack shaft, and the tie rod attachment body is disposed outside the boot.
[0007]
As shown in FIG. 10, the outer peripheral surface of the projection is formed in a tapered surface having a diameter that decreases from the base end to the tip, as shown in FIG. An annular groove B is provided in the middle of the tapered surface. And the fitting part of boot C has penetrated. The through hole D is formed to have a smaller diameter than the outer shape of the protrusion A. By forcibly pushing the through hole D from the tip of the protrusion A into the annular groove B, the through hole D is fitted into the annular groove B. Further, the sealing performance of the fitting portion into which the protrusion A of the boot C is fitted is improved, and foreign matters such as dust and water are prevented from entering the boot C from the fitting portion.
[0008]
[Problems to be solved by the invention]
However, in the rack and pinion type steering device described above, by forcibly pushing the through hole D of the boot C from the tip of the projection A into the annular groove B, and fitting the through hole D into the annular groove B, Since the sealing performance of the fitting portion of the boot C is improved and the tie rod mounting body E is attached to the rack shaft F, it is very difficult to fit the boot C into the protrusion A. Therefore, there is a problem that the mounting workability of the tie rod mounting body E is poor and the cost is increased.
[0009]
In order to solve this problem, the applicant of the present invention forms the fitting portion of the boot into which the protrusion is fitted into a cylindrical shape provided with a fitting inner surface corresponding to the outer shape of the protrusion. A rack-and-pinion type steering device that can be easily fitted into the protrusion of the fitting portion and that can improve the sealing performance of the fitting portion by this fitting has been filed earlier.
[0010]
However, according to this rack and pinion type steering apparatus, the sealing performance of the fitting portion when the longitudinal side one side and the other side of the boot with respect to the fitting portion contracts / extends following the reciprocation of the rack shaft. There was room for improvement.
[0011]
The present invention has been made in view of such circumstances, and by providing a protrusion extending in the circumferential direction on the fitting inner surface of the boot, the fitting portion when the boot expands and contracts following the movement of the rack shaft. It is an object of the present invention to provide a rack and pinion type steering device and a boot used therefor that can improve the sealing performance of the tie rod and improve the mounting workability of the tie rod mounting body.
[0012]
[Means for Solving the Problems]
The rack and pinion type steering device according to the first aspect of the present invention is provided with rack teeth that mesh with a pinion of a pinion shaft that rotates in accordance with a steering operation, and the rack shaft that moves in the left-right direction of the vehicle body has an axial length of the rack shaft. A tie rod mounting body having a protrusion crossing the direction is attached by a screw body that penetrates the protrusion and is fastened to the rack shaft, and is arranged so that both ends are sealed around the rack shaft, In a rack and pinion type steering apparatus provided with a boot capable of extending and contracting having a fitting portion into which the protrusion is fitted, the protrusion is formed in a tapered shape having a small diameter from the proximal end toward the distal end. The fitting portion has a fitting inner surface formed in a tapered shape having a small diameter from the base end to the tip corresponding to the outer shape of the protrusion , and is a cylindrical shape capable of elastic deformation , Circumferential direction on mating inner surface Extending, and the have protrusions that contact is provided with an outer surface of the projection, the projection is elastically deformed fitting portion when fitted to the fitting portion, fitted the by the elastic restoring force of the fitting portion The joint inner surface is configured to contact the outer surface of the protrusion .
[0013]
A boot according to a fourth aspect of the present invention is arranged so that both ends are sealed around a rack shaft that moves in response to a steering operation, and an axial direction of the rack shaft is provided at an intermediate portion of the boot body that can be expanded and contracted. In a boot provided with a fitting portion to which the projection of the tie rod mounting body is provided, which has a projection formed in a taper shape with a small diameter from the proximal end toward the distal end, which is provided in a direction intersecting with The fitting portion has a fitting inner surface formed in a tapered shape having a small diameter from the base end toward the tip , and is a cylindrical shape that can be elastically deformed, and extends in a circumferential direction on the fitting inner surface , And the protrusion which should contact the outer surface of the said protrusion is provided, and when the said protrusion fits into the said fitting part, this fitting part elastically deforms and the said fitting is carried out by the elastic restoring force of this fitting part It is characterized in that the inner surface is arranged to contact the outer surface of the projection .
[0014]
In the first invention and the fourth invention, by fitting the fitting portion of the boot into the protrusion, the fitting inner surface corresponding to the outer shape of the protrusion and the protrusion provided on the fitting inner surface are the outer surface of the protrusion. Since it can contact and can be sealed by these fitting inner surfaces and protrusions, it is possible to improve the sealing performance of the fitting portion when the boot expands and contracts following the movement of the rack shaft. Moreover, since the fitting part is formed in the cylindrical shape provided with the fitting inner surface, the fitting part can be easily fitted into the protrusion, and the attachment work of the tie rod attachment body can be easily performed. Can do.
[0015]
The rack and pinion steering device according to the second aspect of the invention is characterized in that the protrusion is bent by contact with the protrusion.
In the rack and pinion type steering apparatus according to a third aspect of the present invention, the protrusion and the fitting portion are provided at two positions separated in the axial direction of the rack shaft, and the protrusion is formed on the fitting inner surface of each fitting portion. The boot is provided at a circumferential position and on the side where the boot extends when the rack shaft moves.
[0016]
In the second invention, by fitting the fitting portion of the boot into the protrusion, the protrusion is in contact with the outer surface of the protrusion and is bent, and the inner surface of the fitting is in contact with the outer surface of the protrusion. When the amount of expansion / contraction on the one side and the other side in the longitudinal direction with respect to the fitting portion of the boot that moves following the movement of the shaft exceeds a predetermined amount, a part of the fitting inner surface is not in contact with the protrusion. The protrusion provided on the inner surface can be elastically restored to maintain a good contact state with the protrusion, and the sealing performance of the fitting portion can be further enhanced.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof. FIG. 1 is a longitudinal front view showing the configuration of the main part of a rack and pinion type steering apparatus according to the present invention, FIG. 2 is a cross-sectional view further expanding the configuration of the main part, and FIG. 4 and 4 show a boot, in which (a) is a cross-sectional view with a part omitted, (b) is a bottom view, (c) is a longitudinal side view, FIG. 5 is a bottom view of the rack shaft, and FIG. It is sectional drawing of the whole rack and pinion type steering device.
[0018]
The rack and pinion type steering apparatus shown in FIG. 6 meshes with the pinion, with a pinion shaft 1 having one end connected to a steering wheel (steering wheel) and a pinion (not shown) at the other end. A rack shaft 2 provided with rack teeth (not shown) and extending in the left-right direction of the vehicle body, a cylindrically extendable boot 3 disposed around the rack shaft 2, and the rack shaft 2 A rack housing 4 interposed between the boot 3 and supporting the rack shaft 2 and the boot 3, a tie rod mounting body 6 holding the base ends of the pair of tie rods 5 and 5, and the tie rod mounting body 6. A center take-off type rack and pinion type steering device including screw bodies 7 and 7 that pass through the boot 3 and the rack housing 4 and are attached to the middle portion of the rack shaft 2.
[0019]
As shown in FIG. 6, the rack shaft 2 is slidably supported in the axial direction in the rack housing 4 having a cylindrical shape with one end closed. A pair of mounting holes 21 and 21 for mounting the tie rod mounting body 6 are formed at one end of the rack shaft 2 at a predetermined interval in the axial direction. As shown in FIG. 1, these mounting holes 21 and 21 are inclined so as to intersect with the axial direction of the rack shaft 2, and flat receiving seats 22 and 22 are provided in the openings. .
[0020]
As shown in FIG. 6, the rack housing 4 is formed in a bottomed cylindrical shape with one end closed and the other end opened, and a pinion housing 8 is formed in a manner of crossing the rack housing 4 in the middle of the closed side. The pinion shaft 1 is supported inside the pinion housing 8 so as to be rotatable around the axis, and the rotation of the pinion shaft 1 is converted into sliding in the axial direction of the rack shaft 2. It is supposed to be done.
[0021]
As shown in FIG. 6, a window hole 41 for moving the tie rod mounting body 6 with respect to the rack housing 4 is provided in the middle of the open side of the rack housing 4, and the area around the formation area of the window hole 41 is Covered by the boot 3, foreign matter such as dust and water is prevented from entering the rack housing 4 from the window hole 41.
[0022]
As shown in FIG. 1, the tie rod mounting body 6 includes a pair of gripping pieces 61 and 62 that grip the base end portion of the tie rod 5, a connecting piece 63 that connects one end of the gripping pieces 61 and 62, and one gripping A pair of cylindrical projections 64, 64 fixed to the piece 61 at a predetermined interval and intersecting with the axial direction of the rack shaft are provided, and through-holes 65 corresponding to the central holes of the projections 64, 64 are respectively provided. The holding pieces 61 and 62 are drilled. Then, the screw body 7 is inserted into the center hole of the through hole 65 and the protrusion 64 and the screw body is fastened to the mounting hole of the rack shaft, whereby the protrusion is attached to the rack shaft seats 22 and 22. The tie rod mounting body is disposed outside the boot.
[0023]
The boot 3 is formed in a cylindrical shape from a flexible synthetic resin, rubber, or the like, and as shown in FIG. 4, stretchable portions 31, 31 having both ends accordion-shaped, and the stretchable portions 31, 31, A boot body 30 having a connecting cylinder part 32 for connecting 31 is provided, and a flat part 33 facing the tie rod mounting body 6 is provided in the connecting cylinder part 32. Further, both ends of the telescopic parts 31, 31 are detachably attached to the rack housing 4 by attachment rings 9, 9.
[0024]
As shown in FIG. 4A, the flat portion 33 is provided with fitting portions 34 and 34 into which the protrusions 64 and 64 are fitted. The fitting portions 34 and 34 are provided with fitting inner surfaces 34a and 34a corresponding to the outer shapes of the protrusions 64 and 64, and are formed in a cylindrical shape capable of elastic deformation. That is, like the projections 64 and 64, the fitting inner surface 34a and 34a are formed in a tapered shape with a small diameter from the base end toward the tip, and the fitting inner surfaces 34a and 34a are brought into close contact with the outer surfaces of the projections 64 and 64, thereby fitting portions. 34 and 34 can be improved in sealing performance. The fitting portions 34 and 34 and the protrusions 64 and 64 are inclined so as to be separated from the proximal end toward the distal end, as shown in FIG.
[0025]
The fitting inner surfaces 34a, 34a of the fitting portions 34, 34 of the first embodiment are provided with protrusions 35, 35 which are continuous in the circumferential direction and come into contact with the outer surfaces of the protrusions 64, 64. The fitting inner surfaces 34a, 34a and the protrusions 35, 35 are sealed by contact with the protrusions 64, 64.
[0026]
In this case, as shown in FIG. 2, the protrusions 35 and 35 are elastically deformed so that the fitting portions 34 and 34 are expanded by contacting the outer surfaces of the protrusions 64 and 64, and the elasticity of the fitting portions 34 and 34 is also shown. The fitting inner surfaces 35a and 35a come into contact with the outer surfaces of the protrusions 64 and 64 by the restoring force. Thus, when the protrusions 35 and 35 are provided, the elastic restoring force of the fitting parts 34 and 34 can be enlarged compared with the case where the protrusions 35 and 35 are not provided.
[0027]
As shown in FIGS. 3 and 4, a plurality of protrusions 35, 35 are provided at predetermined intervals in the longitudinal direction of the fitting portions 34, 34, but may be one. In addition to being provided continuously in the circumferential direction, the side that extends when the rack shaft 2 is moved, that is, only the left side with respect to the left fitting part 34 and the right side with respect to the right fitting part 34 in FIG. It may be provided. In this case, it is preferable that the protrusions 35 and 35 have a gradually lowering height toward both ends so that no step is generated between the fitting inner surfaces 34a and 34a.
[0028]
1-4, the fitting portions 34, 34 shown in FIGS. 1 to 4 project flanges 36, 36 projecting radially inward from the distal end portion, and the fitting portions 34, 34 of the boot 3 are projected 64, 64. By tightening the screw bodies 7 and 7 in a state of being fitted to each other, the flanges 36 and 36 are pressed between the tip surfaces of the protrusions 64 and 64 and the seats 22 and 22 of the rack shaft 2, and the flanges 36 and 36 are elastically deformed so that the sealing performance of the fitting portions 34 and 34 can be further enhanced.
[0029]
In addition, when the projections 23 and 23 are provided on the receiving seats 22 and 22 of the rack shaft 2 slightly shorter than the thickness of the flanges 36 and 36 and the screw bodies 7 and 7 are fastened to the mounting holes 21 and 21, The protrusions 64 and 64 are received by the protrusions 23 and 23 to prevent an excessive soot pressure from acting on the scissors 36 and 36 and to prevent the scissors 36 and 36 from being damaged by the soot pressure.
[0030]
In the figure, reference numeral 10 denotes a substantially C-shaped slide bearing which is fitted to the outer peripheral surface between the mounting holes 21 and 21 of the rack shaft 2 and contacts the inner peripheral surface of the rack housing 4, and 11 fixes the slide bearing 10. Pins 12 are seal rings provided on the rack shaft 2 inside the sliding bearing 10.
[0031]
Further, the rack and pinion type steering device of the embodiment shown in FIG. 6 is configured as a power steering device that assists sliding of the rack shaft 2 by hydraulic pressure, and a hydraulic cylinder that applies auxiliary force to the rack shaft 2. A piston rod 14 connected coaxially to one end of the rack shaft 2 extends into a cylinder tube 15 connected to the open end of the rack housing 4, and a piston attached to the extended end. 16 is slidably fitted into the cylinder tube 15 via a seal ring 17 wound around the outer periphery thereof.
[0032]
The cylinder tube 15 is a bottomed cylindrical member formed by closing the opposite side of the connection end with the rack housing 4, and on the connection side with the rack housing 4, a seal holder that holds a seal member 18 inside thereof. 19 is attached. The piston rod 14 is liquid-tightly sealed by the seal member 18 and extends into the cylinder tube 15.
[0033]
As described above, the hydraulic cylinder 13 is formed with a pair of oil chambers that are liquid-tightly sealed on both sides of the piston 16 inside the cylinder tube 15, so that hydraulic pressure can be supplied to these oil chambers from the outside. Accordingly, the piston rod 14 is pushed and pulled in the axial length direction by a pressure difference generated on both sides of the piston 16, and a moving force in the axial length direction is applied to the rack shaft 2 connected to the base end of the piston rod 14. It has become.
[0034]
The oil chambers on both sides of the piston 16 are connected to a pair of oil feed ports 81 and 82 provided on the outside of the pinion housing 8 by separate oil feed pipes 20 and 20 respectively connected to corresponding positions outside the cylinder tube 15. It is connected. In the pinion housing 8, a hydraulic pressure supply / discharge operation is performed according to a steering torque applied to the pinion shaft 1 in accordance with a steering wheel operation for steering, and the pinion housing 8 is sent to one of the oil supply ports 81 and 82. A hydraulic control valve is built in, and the hydraulic pressure supplied to the oil supply ports 81 and 82 is supplied to the hydraulic cylinder 13 through the oil supply pipes 20 and 20, and the oil pressure generated in response to this supply is applied to the rack shaft 2. In addition, steering is assisted as described above.
[0035]
When the tie rods 5, 5 of the center take-off type rack and pinion type steering device constructed as described above are attached to the rack shaft 2, the base ends of the tie rods 5, 5 are placed between the holding pieces 61, 62 of the tie rod attachment body 6. The protrusions 64, 64 are inserted in a state where the screw bodies 7, 7 are inserted through the through holes 65 of the holding pieces 61, 62, the through holes 51 at the proximal end of the tie rod 5 and the central holes of the protrusions 64, 64. By fitting into the fitting portions 34 and 34 of the boot 3 and tightening the screw bodies 7 and 7 to the mounting holes 21 and 21 of the rack shaft 2 in this state, the fitting portions 34 and 34 are elastically expanded. The fitting inner surfaces 34a and 34a and the protrusions 35 and 35 can be brought into contact with the outer surfaces of the protrusions 64 and 64 by the elastic restoring force of the fitting portions 34 and 34.
[0036]
Further, when the rack shaft 2 reciprocates in the axial direction through the pinion shaft 1 by rotating the steering wheel, the boot 3 moves to the rack shaft 2 through the tie rod mounting body 6 attached to the rack shaft 2. Follow and reciprocate.
[0037]
Due to the forward movement of the rack shaft 2, for example, the expansion / contraction part 31 on one side in the longitudinal direction (left side in FIG. 1) with respect to the fitting parts 34, 34 of the boot 3 is contracted, and the other side (right side in FIG. Further, due to the backward movement of the rack shaft 2, the stretchable portion 31 on the other side in the longitudinal direction (the right side in FIG. 1) with respect to the fitting portions 34, 34 of the boot 3 is reduced, and the one side (the left side in FIG. 1) is reduced. Will stretch.
[0038]
When one side or the other side in the longitudinal direction with respect to the fitting portions 34, 34 of the boot 3 is thus extended, the extension force of the expansion / contraction portion 31 acts on the extension-side fitting portion 34 so that a part of the fitting inner surface 34a is formed. It will be in the state which does not contact the protrusion 64. FIG.
[0039]
However, in Embodiment 1, the protrusions 35 and 35 are provided on the fitting inner surfaces 34 a and 34 a of the fitting portions 34 and 34, and the fitting inner surfaces 34 a and 34 a and the protrusions 35 and 35 are connected to the protrusions 64 and 64. When the protrusions 35 and 35 are provided, the elastic restoring force of the fitting portions 34 and 34 can be increased as compared with the case where the protrusions 35 and 35 are not provided. Then, the boot 3 moves following the movement of the rack shaft 2, so that a part of the fitting inner surface 34 a is not in contact with the projection 64, but the elastic restoring force of the fitting portion 34 causes the protrusion 35 to move. The contact state with the protrusion can be kept good. Therefore, the sealing performance of the fitting portions 34 and 34 can be improved satisfactorily.
[0040]
Moreover, unlike the conventional example described above, the tie rod attachment body 6 is not attached to the boot 3 in advance. In other words, an annular groove is provided on the outer surface of the protrusions 64, 64, and the fitting portion of the boot 3 is forcibly provided in the annular groove. There is no need to push it in and it will affect the fixation of the tie rod mounting body 6 by a simple operation of simply fitting the fitting portions 34 and 34 to the protrusions 64 and 64 and tightening the screw bodies 7 and 7. Therefore, the sealing performance of the fitting portions 34 and 34 of the boot 3 can be improved.
[0041]
The tie rods 5 and 5 are attached to the rack shaft 2 together with the boot 3 via the tie rod attachment body 6, and sliding in both directions of the rack shaft 2 occurring within the window hole 41 formation range is as follows. It is allowed by the expansion and contraction of the expansion and contraction parts 31 on both sides of the connecting cylinder part 32.
[0042]
The protrusion 35 of the first embodiment described above is formed so that when the fitting portions 34, 34 are fitted into the protrusions 64, 64 and the screw bodies 7, 7 are tightened, they are bent by elastic deformation and overlap the fitting inner surface. May be. In the case of this embodiment, since the other configuration is the same as that of the first embodiment, detailed description is omitted. With this configuration, the amount of expansion / contraction on the one side and the other side in the longitudinal direction with respect to the fitting portions 34, 34 of the boot 3 that moves following the movement of the rack shaft 2 becomes a predetermined amount or more, and the fitting inner surfaces 34a, When a part of 34 a is not in contact with the protrusions 64, 64, the protrusions 35, 35 can be elastically restored to maintain a good contact state with the protrusions 64, 64, so When the amount exceeds a predetermined amount, the sealing property can be further enhanced.
[0043]
Further, the fitting parts 34, 34 of the first embodiment eliminate the flanges 36, 36 at the tip part, and form at least the tip part with a smaller diameter than the outer shape of the projections 64, 64 as shown in FIG. You may comprise so that the elastic restoring force at the time of making it elastically deform so that a front-end | tip part may be expanded by fitting to protrusion 64,64 may be enlarged. In the case of this embodiment, since the other configuration is the same as that of the first embodiment, detailed description is omitted. With this configuration, the sealing performance of the fitting portions 34 and 34 can be improved satisfactorily as in the first embodiment. Also in this embodiment, the protrusion 35 may be formed so as to be bent by elastic deformation and overlap with the fitting inner surface as described above.
[0044]
In the embodiment described above, the structure in which the tie rod attachment body 6 is attached to the rack shaft 2 using the two screw bodies 7 and 7 has been described, but in addition, to the rack shaft 2 of the tie rod attachment body 6. As shown in FIG. 8, one screw body 7 may be used for attachment.
[0045]
Further, the screw bodies 7, 7 for attaching the tie rod attachment body 6 to the rack shaft 2 are configured to be inclined so as to intersect the axial length direction of the rack shaft 2, as shown in FIGS. As shown in FIG. 9, the rack shaft 2 may be configured to be substantially orthogonal to the axial length direction. These embodiments of FIGS. 8 and 9 are basically the same as the embodiments shown in FIGS. 1 to 7, and therefore, common reference numerals are used and detailed description thereof is omitted.
[0046]
【The invention's effect】
As described above in detail, according to the first invention and the fourth invention, the fitting inner surface corresponding to the outer shape of the protrusion and the protrusion provided on the fitting inner surface are brought into contact with the outer surface of the protrusion, Since it can seal with a protrusion, the sealing performance of the fitting part when a boot expands and contracts following the movement of a rack shaft can be improved satisfactorily. Moreover, since it can be sealed by fitting the cylindrical fitting inner surface into the protrusion, the attaching operation of the tie rod attaching body can be easily performed, and the cost can be reduced.
[0047]
According to the second invention, the amount of expansion / contraction on the one side and the other side in the longitudinal direction with respect to the fitting portion of the boot that moves following the movement of the rack shaft is not less than a predetermined amount, and a part of the fitting inner surface is a protrusion. In the case of no contact, the protrusion provided on the inner surface of the fitting can be elastically restored and the contact state with the protrusion can be maintained well, so that the sealing performance of the fitting portion can be further enhanced.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view showing a configuration of a main part of a rack and pinion type steering apparatus according to the present invention.
FIG. 2 is a cross-sectional view further enlarging the configuration of the main part of the rack and pinion type steering apparatus according to the present invention.
FIG. 3 is an exploded longitudinal sectional view of a configuration of a main part of a rack and pinion type steering apparatus according to the present invention.
4A and 4B show a boot according to the present invention, in which FIG. 4A is a cross-sectional view with a part omitted, FIG. 4B is a bottom view, and FIG. 4C is a longitudinal side view.
FIG. 5 is a bottom view of the rack shaft of the rack and pinion type steering apparatus according to the present invention.
FIG. 6 is an overall cross-sectional view of a rack and pinion type steering apparatus according to the present invention.
FIG. 7 is an enlarged cross-sectional view of another embodiment of the rack and pinion steering device according to the present invention.
FIG. 8 is a cross-sectional view of a main part showing another embodiment of the rack and pinion steering device according to the present invention.
FIG. 9 is a cross-sectional view of a main part showing another embodiment of a rack and pinion type steering apparatus according to the present invention.
FIG. 10 is a cross-sectional view of a rack and pinion type steering apparatus showing a conventional example.
[Explanation of symbols]
2 Rack shaft 3 Boot 34 Fitting part 34a Fitting inner surface 35 Projection 6 Tie rod mounting body 64 Projection 7 Screw body

Claims

A rack tooth that meshes with a pinion of a pinion shaft that rotates in response to a steering operation is provided, and a tie rod mounting body that has a protrusion that intersects the axial length direction of the rack shaft is provided on the rack shaft that moves in the left-right direction of the vehicle body. Is attached by a screw body that penetrates the rack shaft and is fastened to the rack shaft, and is arranged so that both end portions are sealed around the rack shaft, and has a fitting portion to which the protrusion is fitted. In the rack-and-pinion type steering device provided with a boot capable of supporting, the protrusion is formed in a tapered shape having a small diameter from the proximal end to the distal end, and the fitting portion corresponds to the outer shape of the protrusion And a fitting inner surface formed in a tapered shape having a small diameter from the proximal end toward the distal end , is a cylindrical shape that can be elastically deformed , extends circumferentially on the fitting inner surface , and the projection the ridges in contact with the outer surface Configured vignetting and, fitting portion when the projection is fitted into the fitting portion is elastically deformed, the fitting inner surface by elastic restoring force of the fitting portion contacts the outer surface of the projection A rack and pinion type steering device characterized by that .

The rack-and-pinion steering device according to claim 1, wherein the protrusion is bent by contact with the protrusion.

The protrusion and the fitting portion are provided at two locations separated in the axial direction of the rack shaft, and the protrusion is a circumferential position on the fitting inner surface of each fitting portion, and the rack shaft moves when the rack shaft moves. The rack-and-pinion type steering device according to claim 1 or 2, wherein the boot-and-steering device is provided on a side where the boot extends.

It is arranged so that both ends are sealed around the rack shaft that moves according to the steering operation, and protrudes in a direction intersecting with the axial direction of the rack shaft at the intermediate portion of the boot body that can be expanded and contracted. and the boot formed by providing the fitting portion projections are fitted in the tie rod mounting member having a proximal projection that is tapered to a smaller diameter toward the tip from the fitting portion, the proximal end It has a fitting inner surface formed in a tapered shape with a small diameter from the tip to the tip, is a cylindrical shape that can be elastically deformed , extends circumferentially on the fitting inner surface, and contacts the outer surface of the protrusion When the protrusion is fitted to the fitting portion, the fitting portion is elastically deformed, and the fitting inner surface contacts the outer surface of the protrusion by the elastic restoring force of the fitting portion. A boot characterized by being configured to do so .