JP3608918B2

JP3608918B2 - Rack and pinion steering system

Info

Publication number: JP3608918B2
Application number: JP27203797A
Authority: JP
Inventors: 崇田代
Original assignee: Koyo Seiko Co Ltd
Current assignee: Koyo Seiko Co Ltd
Priority date: 1997-09-17
Filing date: 1997-09-17
Publication date: 2005-01-12
Anticipated expiration: 2017-09-17
Also published as: JPH1191593A

Description

【０００１】
【発明の属する技術分野】
本発明は、ラックピニオン式ステアリング装置におけるラックの支持構造の改良に関する。
【０００２】
【従来の技術】
操舵により回転するピニオンと、このピニオンに噛み合うラックを覆うハウジングと、このハウジングに設けられた保持孔に挿入されるラック支持部材を備えるラックピニオン式ステアリング装置が従来から用いられている。
【０００３】
そのラック支持部材は、そのラックに近接する方向と離反する方向とに往復移動可能に保持孔に挿入される。その保持孔の開口は、そのラック支持部材の往復移動方向に沿う軸回りの回転によりハウジングにねじ合わされる閉鎖部材により閉鎖される。そのラック支持部材と閉鎖部材とで挟み込まれる圧縮コイルバネにより、そのラック支持部材にラックの背面に向かう弾力が付与されている。
【０００４】
そのラック支持部材の往復移動によりラックの曲がり等が吸収され、ピニオンとラックの円滑な噛み合いが確保されている。また、そのラック支持部材のラックから離反する方向への移動は閉鎖部材により阻止可能とされ、これにより、そのラック支持部材の往復移動のストロークは、そのラック支持部材と閉鎖部材との間隔に対応するものとされている。そのラック支持部材の往復移動のストロークの調節は、そのラック支持部材のハウジングへのねじ込み量を調節することで行われている。
【０００５】
【発明が解決しようとする課題】
従来の構成では、そのハウジングにねじ合わされる閉鎖部材の緩みを防止するため、その閉鎖部材の外周にロックナットをねじ合わせている。そのため部品点数が増大するという問題がある。
【０００６】
また、そのラック支持部材と閉鎖部材との間隔調節に際しては、ラックとピニオンの噛み合い部におけるバックラッシ量に対応するラックの回転量を測定し、そのバックラッシ量が公差範囲に納まるように閉鎖部材のハウジングへのねじ込み量を決定していた。そのようなバックラッシ量の測定は組み立てを非常に面倒なものにしていた。
【０００７】
本発明は、上記従来技術の問題を解決することのできるラックピニオン式ステアリング装置を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明のラックピニオン式ステアリング装置は、操舵により回転するピニオンと、そのピニオンに噛み合うラックと、そのラックを覆うハウジングと、そのハウジングに設けられた保持孔に、そのラックに近接する方向と離反する方向とに往復移動可能に挿入されるラック支持部材と、その保持孔の一端側の開口を閉鎖するように、そのラック支持部材の往復移動方向に沿う軸回りの回転によりハウジングにねじ合わされる閉鎖部材と、そのラック支持部材と閉鎖部材とで挟み込まれる圧縮コイルバネとを備える。そのコイルバネによりラック支持部材にラックの背面に向かう弾力が付与される。そのラック支持部材は、前記ラックに対してラック支持部材の往復移動方向に沿う軸まわりの回転が規制され、そのラックは、前記ハウジングに対してラック支持部材の往復移動方向に沿う軸まわりの回転が規制されている。そのコイルバネは、そのラック支持部材の往復移動方向に沿う軸回りの回転が規制されるように、その一端が前記ラック支持部材に接続される。その閉鎖部材と同行回転する回転許容面と回転阻止面とが設けられ、その閉鎖部材の前記ハウジングへのねじ込み方向の回転が許容されるように、その回転許容面は閉鎖部材のハウジングへのねじ込み時にコイルバネの他端に対し相対滑り可能に接し、その閉鎖部材の前記ハウジングへのねじ込み解除方向への回転が規制されるように、その回転阻止面は閉鎖部材のハウジングへのねじ込み解除時にコイルバネの他端に相対変位不能に接する。
本発明の構成によれば、閉鎖部材は、ハウジングへのねじ込み解除方向への回転が規制されるようにコイルバネの他端にかみ合わされ、そのコイルバネは、一端がラック支持部材の往復移動方向に沿う軸まわりの回転が規制されるようにラック支持部材に接続され、そのラック支持部材は、自身の往復移動方向に沿う軸まわりのラックに対する回転が規制され、そのラックは、ラック支持部材の往復移動方向に沿う軸まわりのハウジングに対する回転が規制されている。これにより、その閉鎖部材のハウジングへのねじ込み解除方向への回転を、ロックナット等の専用部材を用いることなく規制できる。
【０００９】
そのコイルバネは、前記閉鎖部材のハウジングへのねじ込み解除方向への回転阻止力により径方向外方へ弾性変形することで、前記保持孔の内周に押し付けられるのが好ましい。
そのコイルバネが保持孔の内周に押し付けられることで、閉鎖部材のハウジングへのねじ込み解除方向への回転を阻止する摩擦力が、そのコイルバネと保持孔との間に生じる。
【００１０】
その閉鎖部材の内端から前記保持孔内に突出する複数の突起が設けられ、それら突起は、そのハウジングに対して閉鎖部材と共に前記ねじ込み方向に同行回転することでコイルバネの他端に順次接することができるように、そのラック支持部材の往復移動方向に沿う軸中心の円に沿って並列され、各突起が前記回転許容面と前記回転阻止面とを有するのが好ましい。
これにより、簡単な構成で、閉鎖部材のハウジングへのねじ込み方向の回転を許容すると共にねじ込み解除方向への回転を規制できる。
【００１１】
さらに、そのラック支持部材の前記往復移動のストロークは、そのラック支持部材と閉鎖部材との間隔に対応し、そのラック支持部材側に前記コイルバネの一端が移動可能に挿入される溝が円弧に沿い形成され、その溝の一端側の内面にコイルバネの一端が接することで、そのコイルバネはラック支持部材に対して閉鎖部材のハウジングへのねじ込み方向の回転が阻止され、その溝の他端側の内面にコイルバネの一端が接することで、そのコイルバネはラック支持部材に対して閉鎖部材のハウジングへのねじ込み解除方向の回転が阻止され、そのコイルバネが、支持部材に押し付けられるまでハウジングにねじ込まれた閉鎖部材と共に、そのねじ込み解除方向に設定量だけ回転できるように、その溝の円弧に沿う寸法が設定されているのが好ましい。
この構成によれば、閉鎖部材をハウジングにねじ込むと、閉鎖部材とコイルバネとの間の摩擦によりコイルバネが閉鎖部材と共にラック支持部材に対して回転し、コイルバネの一端は円弧に沿う溝の他端側から一端側に移動する。その溝の一端側の内面に接することで、それ以上のコイルバネのラック支持部材に対する回転は阻止される。その閉鎖部材を、ラック支持部材に押し付けられるまでハウジングにねじ込んだ後に、そのねじ込み解除方向に回転させると、そのコイルバネが閉鎖部材と共に回転することで、そのコイルバネの一端は円弧に沿う溝の一端側から他端側の内面に接するまで移動する。その溝の他端側においてコイルバネの一端が溝の内面に接することで、そのコイルバネを介して閉鎖部材のねじ込み解除方向への回転を阻止できる。その溝は設定寸法の長さの円弧に沿い形成されているので、ラック支持部材に押し付けられるまでねじ込まれた閉鎖部材のねじ込み解除方向への回転量は設定量になる。これにより、その設定量に応じてラック支持部材と閉鎖部材との間隔、すなわち、ラック支持部材の往復移動のストロークを設定できる。
【００１２】
【発明の実施の形態】
以下、図面を参照して本発明の実施形態を説明する。
【００１３】
図１および図２に示す車両用ラックピニオン式ステアリング装置１は、ステアリングホイールに連結される入力軸２と、この入力軸２に一体化されるヘリカルピニオン６と、このピニオン６に噛み合うヘリカルラック７と、このラック７を覆うアルミダイカスト製のハウジング５とを備えている。その入力軸２はベアリング３、４を介しハウジング５に支持される。その入力軸２とハウジング５との間に筒状のネジ部材１０がねじ込まれ、このネジ部材１０により入力軸２とベアリング３、４とピニオン６の軸方向移動が防止され、そのネジ部材１０と入力軸２との間にオイルシール１１が介在されている。
【００１４】
図２に示すように、そのハウジング５の一方から突出するラック７はシリンダチューブ８により覆われ、そのシリンダチューブ８はハウジング５の一端に形成された円筒部５ａに圧入されている。そのラック７は、そのハウジング５とシリンダチューブ８とにより図外ブッシュを介して車両幅方向に往復移動可能に支持され、これにより、ハウジング５に対して後述のサポートヨーク１６の往復移動方向に沿う軸まわりの回転が規制されている。そのラック７の両端にタイロッドとナックルアームを介して操舵用車輪が連結される。これにより、ステアリングホイールの操作により入力軸２が回転すると、その回転によりピニオン６が回転し、このピニオン６の回転がラック７に伝達されることでラック７は車両幅方向に移動する。このラック７の車両幅方向移動が操舵用車輪に伝達されることで車両の操舵がなされる。
【００１５】
そのハウジング５に、円筒面に沿う保持孔１５が形成され、この保持孔１５に外周面が円柱面である焼結金属製サポートヨーク（ラック支持部材）１６が、ラックに近接する方向と離反する方向（図１において左右方向）に往復移動可能に挿入されている。そのサポートヨーク１６におけるラック７との対向端側（図１において右方側）に、ラック支持用凹部１６ｂが形成されている。その凹部１６ｂに合成樹脂製のシート１７を介してラック７の背面側が支持され、これにより、サポートヨーク１６はラック７に対する上記往復移動方向に沿う軸まわりの回転が規制されている。
【００１６】
その保持孔１５の一端側（図１において左方側）の開口は金属製プラグ（閉鎖部材）１８により閉鎖されている。すなわち、そのプラグ１８の外周に雄ねじ１８′が形成され、その保持孔１５の内周に雌ねじ１５′が形成されることで、そのプラグ１８は上記サポートヨーク１６の往復移動方向に沿う軸回りの回転により保持孔１５にねじ合わされる。本実施形態では、その雄ねじ１８′と雌ねじ１５′は右ネジとされている。また、そのねじ合わせ前にプラグ１８の外周に液体パッキンが塗布され、そのねじ合わせ後にプラグ１８と保持孔１５との間に介在する液体パッキンが固化することで、そのプラグ１８のハウジング５へのねじ込み方向の回転が規制される。なお、その液体パッキンの固化に要する時間は、後述のプラグ１８とサポートヨーク１６との間隔δの設定を阻害することがないように十分な時間とされる。そのプラグ１８と上記ラック７との間にサポートヨーク１６が配置される。そのプラグ１８の外端側には工具係合用６角孔１８ａが形成されている。
【００１７】
そのサポートヨーク１６に、プラグ１８との対向端側において開口するバネ挿入孔１６ａが形成されている。そのバネ挿入孔１６ａに圧縮コイルバネ２４が挿入されている。そのコイルバネ２４がプラグ１８とサポートヨーク１６とに挟み込まれて圧縮されることで、サポートヨーク１６にラック７の背面に向かう弾力が付与される。そのサポートヨーク１６の往復移動により、ピニオン６及びラック７の歯の加工誤差やラック７の曲がりが吸収され、ラック７とピニオン６との噛み合いの円滑化が図られる。そのサポートヨーク１６の往復移動のストロークは、そのサポートヨーク１６とプラグ１８との間隔δに対応する。図３に示すように、そのコイルバネ２４を構成する素線は、その一端２４ａが後述の溝３０に挿入可能なようにコイルバネ２４の軸方向に沿うように屈曲され、他端２４ｂが後述のように突起４０と噛み合い可能とされている。
【００１８】
そのコイルバネ２４は、そのサポートヨーク１６の往復移動方向に沿う軸回りの回転が規制されるように、その一端２４ａがサポートヨーク１６に接続されている。すなわち、図１、図４に示すように、そのサポートヨーク１６のバネ挿入孔１６ａの底部に、上記コイルバネ２４の一端が移動可能に挿入される溝３０が円弧に沿い形成されている。図４に示すように、その溝３０の一端側にコイルバネ２４の一端２４ａが接することで、コイルバネ２４はサポートヨーク１６に対してプラグ１８のハウジング５へのねじ込み方向（図４において矢印Ａ方向）の回転が阻止される。その溝３０の他端側の内面にコイルバネ２４の一端２４ａが接することで、そのコイルバネ２４はサポートヨーク１６に対してプラグ１８のハウジング５へのねじ込み解除方向（図４において矢印Ｂ方向）の回転が阻止される。
【００１９】
そのプラグ１８は、ハウジング５へのねじ込み方向の回転が許容されると共にねじ込み解除方向への回転が規制されるように、そのコイルバネ２４の他端２４ｂにかみ合わされる。すなわち、図５、図６に示すように、そのプラグ１８の内端から保持孔１５内に突出する複数の突起４０が設けられている。それら突起４０は、そのプラグ１８と共にハウジング５に対して前記ねじ込み方向に同行回転することでコイルバネ２４の他端２４ｂに順次接することができるように、そのサポートヨーク１６の往復移動方向に沿う軸中心の円に沿って並列する。各突起４０は、プラグ１８のハウジング５へのねじ込み時にコイルバネ２４の他端２４ｂに相対滑り可能に接する回転許容面４０ａと、ねじ込み解除時にコイルバネ２４の他端２４ｂに相対変位不能に接する回転阻止面４０ｂとを有する。本実施形態では、その回転許容面４０ａは、プラグ１８からサポートヨーク１６に向かうに従い、プラグ１８のハウジング５へのねじ込み解除方向に向かうように、サポートヨーク１６の往復移動方向に対して傾斜し、その回転阻止面４０ｂはサポートヨーク１６の往復移動方向に沿う。
【００２０】
そのプラグ１８は、ハウジング５へのねじ込み解除方向への回転が規制されるようにコイルバネ２４の他端２４ｂにかみ合わされ、そのコイルバネ２４は、一端２４ａがサポートヨーク１６の往復移動方向に沿う軸まわりの回転が規制されるようにサポートヨーク１６に接続され、そのサポートヨーク１６は、自身の往復移動方向に沿う軸まわりのラック７に対する回転が規制され、そのラック７は、サポートヨーク１６の往復移動方向に沿う軸まわりのハウジング５に対する回転が規制されている。これにより、そのプラグ１８のハウジング５へのねじ込み解除方向への回転を、ロックナット等の専用部材を用いることなく規制できる。上記実施形態では、プラグ１８に突起４０を形成する簡単な構成でプラグ１８のハウジング５へのねじ込み方向の回転を許容すると共にねじ込み解除方向への回転を規制できる。
【００２１】
そのコイルバネ２４は、そのプラグ１８のハウジング５へのねじ込み解除方向への回転の阻止力の作用を受け、その力により径方向外方へ弾性変形する。この弾性変形によりコイルバネ２４が保持孔１５の内周に押し付けられるように、コイルバネ２４と保持孔１５の寸法が定められている。そのコイルバネ２４が保持孔１５の内周に押し付けられることで、プラグ１８のハウジング５へのねじ込み解除方向への回転を阻止する摩擦力が、そのコイルバネ２４と保持孔１５との間に生じる。これにより、より確実にプラグ１８のねじ込み解除方向への回転を規制できる。
【００２２】
上記構成において、プラグ１８をハウジング５にねじ込むと、プラグ１８の突起４０の回転許容面４０ａとコイルバネ２４の他端２４ｂとの間の摩擦によりコイルバネ２４がプラグ１８と共にサポートヨーク１６に対して回転し、コイルバネ２４の一端２４ａは円弧に沿う溝３０の他端側から一端側に移動する。その溝３０の一端側の内面に接することで、それ以上のコイルバネ２４のサポートヨーク１６に対する回転は阻止される。この後、さらにプラグ１８を、サポートヨーク１６に押し付けられるまでハウジング５にねじ込んだ後に、ねじ込み解除方向に回転させると、プラグ１８の突起４０の回転阻止面４０ｂとコイルバネ２４の他端２４ｂとが接することで、そのコイルバネ２４はプラグ１８と共に回転する。この回転により、コイルバネ２４の一端２４ａは円弧に沿う溝３０の一端側から他端側に移動する。その溝３０の他端側においてコイルバネ２４の一端２４ａが溝３０の内面に接することで、そのコイルバネ２４を介してプラグ１８のねじ込み解除方向への回転を阻止できる。
【００２３】
そのサポートヨーク１６に押し付けられるまでねじ込まれたプラグ１８と共にねじ込み解除方向へ回転するコイルバネ２４の回転量が設定量になるように、その溝３０の円弧方向に沿う寸法が設定されている。よって、その設定量に応じてサポートヨーク１６とプラグ１８との間隔δ、すなわち、サポートヨーク１６の往復移動のストロークを設定できる。これにより、組み立てに際してラック７とピニオン６の噛み合い部におけるバックラッシ量を測定することなく、そのバックラッシ量を公差範囲に納めることができ、組み立ての容易化を図ることができる。なお、そのプラグ１８と共にねじ込み解除方向へ回転するコイルバネ２４の回転量は、突起４０の間隔に応じて変動することから、そのバックラッシを公差範囲に納めることができるように、その突起４０の間隔を定める。
【００２４】
なお、本発明は上記各実施形態に限定されるものではない。例えば、突起４０の回転許容面４０ａと回転阻止面４０ｂの形状は上記実施形態に限定されず、回転許容面４０ａは、プラグ１８のハウジング５へのねじ込み時にコイルバネ２４の他端２４ｂに対して相対滑り可能であればよく、また、回転阻止面４０ｂはねじ込み解除時にコイルバネ２４の他端２４ｂに相対変位不能に接するものであればよい。
【００２５】
【発明の効果】
本発明によれば、部品点数の低減と組み立ての容易化を図ることのできるラックピニオン式ステアリング装置を提供でくる。
【図面の簡単な説明】
【図１】本発明の実施形態のラックピニオン式ステアリング装置の断面図
【図２】本発明の実施形態のラックピニオン式ステアリング装置の正面図
【図３】本発明の実施形態のコイルバネの側面図
【図４】図１のＩＶ‐ＩＶ線断面図
【図５】本発明の実施形態のプラグの側面図
【図６】図１のＶＩ‐ＶＩ線断面図
【符号の説明】
５ハウジング
６ピニオン
７ラック
１５保持孔
１６サポートヨーク（ラック支持部材）
１８プラグ（閉鎖部材）
２４コイルバネ
３０溝
４０突起
４０ａ回転許容面
４０ｂ回転阻止面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a rack support structure in a rack and pinion type steering apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a rack and pinion type steering apparatus including a pinion that rotates by steering, a housing that covers a rack that meshes with the pinion, and a rack support member that is inserted into a holding hole provided in the housing has been used.
[0003]
The rack support member is inserted into the holding hole so as to be able to reciprocate in a direction close to and away from the rack. The opening of the holding hole is closed by a closing member screwed to the housing by rotation around the axis along the reciprocating direction of the rack support member. The compression coil spring sandwiched between the rack support member and the closing member imparts elasticity to the rack support member toward the back surface of the rack.
[0004]
Due to the reciprocating movement of the rack support member, bending of the rack and the like are absorbed, and a smooth engagement between the pinion and the rack is ensured. Further, the movement of the rack support member in the direction away from the rack can be prevented by the closing member, and the stroke of the reciprocating movement of the rack support member corresponds to the interval between the rack support member and the closing member. It is supposed to be. The reciprocating stroke of the rack support member is adjusted by adjusting the screwing amount of the rack support member into the housing.
[0005]
[Problems to be solved by the invention]
In the conventional configuration, a lock nut is screwed to the outer periphery of the closing member in order to prevent loosening of the closing member screwed to the housing. Therefore, there is a problem that the number of parts increases.
[0006]
Further, when adjusting the distance between the rack support member and the closing member, the amount of rotation of the rack corresponding to the backlash amount at the meshing portion of the rack and pinion is measured, and the housing of the closing member is adjusted so that the backlash amount falls within the tolerance range. The amount of screwing was determined. Such measurement of the amount of backlash has made the assembly very cumbersome.
[0007]
It is an object of the present invention to provide a rack and pinion type steering device that can solve the above-described problems of the prior art.
[0008]
[Means for Solving the Problems]
The rack and pinion type steering device of the present invention is separated from the direction close to the rack by a pinion that rotates by steering, a rack that meshes with the pinion, a housing that covers the rack, and a holding hole provided in the housing. And a rack support member inserted so as to be reciprocally movable in a direction, and a closure screwed to the housing by rotation about the axis along the reciprocating direction of the rack support member so as to close the opening on one end side of the holding hole A member and a compression coil spring sandwiched between the rack support member and the closing member. The coil spring imparts elasticity to the rack support member toward the back surface of the rack. The rack support member is restricted from rotating about the axis along the reciprocating direction of the rack support member with respect to the rack, and the rack rotates about the axis along the reciprocating direction of the rack support member with respect to the housing. Is regulated. One end of the coil spring is connected to the rack support member so that rotation around the axis along the reciprocating direction of the rack support member is restricted. Its closure member and the rotation permitting surface and the rotation blocking surface which rotates together is provided, screwing of the rotation of the screwing direction to the housing of the closure member is allowed, to the housing of the rotation permitting surface closure member The rotation preventing surface of the coil spring is released when the closure member is unscrewed into the housing so that the other end of the coil spring is sometimes slidably in contact with the other end of the coil spring and the rotation of the closure member in the unscrewing direction to the housing is restricted . Contact the other end so that it cannot be displaced relatively .
According to the configuration of the present invention, the closing member is engaged with the other end of the coil spring so that the rotation in the screwing release direction to the housing is restricted, and the coil spring has one end along the reciprocating direction of the rack support member. The rack support member is connected to the rack support member so that the rotation around the axis is restricted. The rack support member is restricted from rotating relative to the rack around the axis along the reciprocal movement direction of the rack support member. Rotation relative to the housing about the axis along the direction is restricted. Thereby, rotation to the screwing release direction to the housing of the closure member can be controlled without using exclusive members, such as a lock nut.
[0009]
As the coil spring, by elastic deformation by rotation inhibiting force in the screwing direction of releasing the housing of the closure member radially outward, preferably is the inner Installing push the perimeter of the holding hole.
By the coil spring is Installing pushed to the inner circumference of the holding hole, the frictional forces preventing rotation of the screw-releasing direction to the housing of the closure member occurs between the coil spring and the holding hole.
[0010]
A plurality of protrusions projecting from the inner end of the closing member into the holding hole are provided, and these protrusions sequentially contact the other end of the coil spring by rotating together with the closing member in the screwing direction with respect to the housing. as can, in parallel along a circle of axial center along the reciprocating direction of the rack support member, preferably each projection has said rotation preventing surface and the rotation permitting surface.
Thus, with a simple configuration, it can restrict the rotation of the screw-releasing direction while permitting rotation of the screwing direction of the housings of the closure member.
[0011]
Further, the stroke of the reciprocating movement of the rack support member corresponds to the interval between the rack support member and the closing member, and a groove in which one end of the coil spring is movably inserted on the rack support member side is along an arc. The one end of the coil spring is in contact with the inner surface on one end side of the groove so that the coil spring is prevented from rotating in the screwing direction of the closing member into the housing with respect to the rack support member, and the inner surface on the other end side of the groove When the coil spring is in contact with one end of the coil spring, the coil spring is prevented from rotating in the unscrewing direction of the closing member into the housing with respect to the rack support member, and the closing member is screwed into the housing until the coil spring is pressed against the support member. At the same time, it is preferable that the dimension along the arc of the groove is set so that it can be rotated by a set amount in the unscrewing direction. Arbitrariness.
According to this configuration, when the closing member is screwed into the housing, the coil spring rotates with the closing member together with the closing member due to friction between the closing member and the coil spring, and one end of the coil spring is the other end side of the groove along the arc. To one end. By contacting the inner surface of one end of the groove, further rotation of the coil spring relative to the rack support member is prevented. When the closure member is screwed into the housing until it is pressed against the rack support member and then rotated in the unscrewing direction, the coil spring rotates together with the closure member, so that one end of the coil spring is one end side of the groove along the arc. Until it touches the inner surface of the other end. Since one end of the coil spring is in contact with the inner surface of the groove on the other end side of the groove, the closing member can be prevented from rotating in the unscrewing direction via the coil spring. Since the groove is formed along an arc having a set length, the amount of rotation of the closing member screwed in until it is pressed against the rack support member in the unscrewing direction becomes the set amount. Thereby, the interval between the rack support member and the closing member, that is, the stroke of the reciprocation of the rack support member can be set according to the set amount.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
A vehicle rack and pinion type steering device 1 shown in FIGS. 1 and 2 includes an input shaft 2 coupled to a steering wheel, a helical pinion 6 integrated with the input shaft 2, and a helical rack 7 meshing with the pinion 6. And an aluminum die-cast housing 5 that covers the rack 7. The input shaft 2 is supported by the housing 5 via bearings 3 and 4. A cylindrical screw member 10 is screwed between the input shaft 2 and the housing 5. The screw member 10 prevents the input shaft 2, the bearings 3, 4 and the pinion 6 from moving in the axial direction. An oil seal 11 is interposed between the input shaft 2 and the input shaft 2.
[0014]
As shown in FIG. 2, the rack 7 protruding from one side of the housing 5 is covered with a cylinder tube 8, and the cylinder tube 8 is press-fitted into a cylindrical portion 5 a formed at one end of the housing 5. The rack 7 is supported by the housing 5 and the cylinder tube 8 so as to be reciprocally movable in the vehicle width direction via a bush (not shown), and thereby, along the reciprocating direction of a support yoke 16 described later with respect to the housing 5. The rotation around the axis is restricted. Steering wheels are connected to both ends of the rack 7 via tie rods and knuckle arms. Thus, when the input shaft 2 is rotated by the operation of the steering wheel, the pinion 6 is rotated by the rotation, and the rotation of the pinion 6 is transmitted to the rack 7 so that the rack 7 moves in the vehicle width direction. The movement of the rack 7 in the vehicle width direction is transmitted to the steering wheel, whereby the vehicle is steered.
[0015]
A holding hole 15 is formed in the housing 5 along the cylindrical surface, and a sintered metal support yoke (rack support member) 16 whose outer peripheral surface is a cylindrical surface is separated from the holding hole 15 in a direction close to the rack. It is inserted so as to be able to reciprocate in the direction (left-right direction in FIG. 1). A rack supporting recess 16b is formed on the side of the support yoke 16 facing the rack 7 (on the right side in FIG. 1). The back side of the rack 7 is supported by the concave portion 16b via a synthetic resin sheet 17, whereby the support yoke 16 is restricted from rotating about the axis along the reciprocating direction relative to the rack 7.
[0016]
An opening on one end side (left side in FIG. 1) of the holding hole 15 is closed by a metal plug (closing member) 18. That is, a male screw 18 ′ is formed on the outer periphery of the plug 18, and a female screw 15 ′ is formed on the inner periphery of the holding hole 15, so that the plug 18 is rotated around the axis along the reciprocating direction of the support yoke 16. It is screwed into the holding hole 15 by rotation. In the present embodiment, the male screw 18 'and the female screw 15' are right-handed screws. Further, liquid packing is applied to the outer periphery of the plug 18 before the screw alignment, and the liquid packing interposed between the plug 18 and the holding hole 15 is solidified after the screw alignment, so that the plug 18 is attached to the housing 5. The rotation in the screwing direction is restricted. It should be noted that the time required for solidifying the liquid packing is sufficient so as not to hinder the setting of the interval δ between the plug 18 and the support yoke 16 described later. A support yoke 16 is disposed between the plug 18 and the rack 7. A tool engaging hexagonal hole 18 a is formed on the outer end side of the plug 18.
[0017]
A spring insertion hole 16 a is formed in the support yoke 16 so as to open on the side facing the plug 18. A compression coil spring 24 is inserted into the spring insertion hole 16a. The coil spring 24 is sandwiched and compressed between the plug 18 and the support yoke 16, so that the support yoke 16 is given elasticity toward the back surface of the rack 7. By the reciprocating movement of the support yoke 16, processing errors of the teeth of the pinion 6 and the rack 7 and the bending of the rack 7 are absorbed, and the meshing between the rack 7 and the pinion 6 is facilitated. The reciprocating stroke of the support yoke 16 corresponds to the distance δ between the support yoke 16 and the plug 18. As shown in FIG. 3, the wire constituting the coil spring 24 is bent along the axial direction of the coil spring 24 so that one end 24a thereof can be inserted into a groove 30 described later, and the other end 24b is described later. It is possible to engage with the protrusion 40.
[0018]
One end 24a of the coil spring 24 is connected to the support yoke 16 so that rotation around the axis along the reciprocating direction of the support yoke 16 is restricted. That is, as shown in FIGS. 1 and 4, a groove 30 into which one end of the coil spring 24 is movably inserted is formed along an arc at the bottom of the spring insertion hole 16 a of the support yoke 16. As shown in FIG. 4, one end 24 a of the coil spring 24 is in contact with one end side of the groove 30, so that the coil spring 24 is screwed into the housing 5 of the plug 18 with respect to the support yoke 16 (direction of arrow A in FIG. 4). Is prevented from rotating. When one end 24a of the coil spring 24 is in contact with the inner surface on the other end side of the groove 30, the coil spring 24 rotates in the direction in which the plug 18 is screwed into the housing 5 with respect to the support yoke 16 (in the direction of arrow B in FIG. 4). Is blocked.
[0019]
The plug 18 is engaged with the other end 24b of the coil spring 24 so that rotation in the screwing direction to the housing 5 is allowed and rotation in the screwing release direction is restricted. That is, as shown in FIGS. 5 and 6, a plurality of protrusions 40 that protrude from the inner end of the plug 18 into the holding hole 15 are provided. The protrusions 40 are rotated together with the plug 18 in the screwing direction with respect to the housing 5 so that the protrusions 40 can be sequentially brought into contact with the other end 24b of the coil spring 24, so that the axial center of the support yoke 16 along the reciprocating movement direction can be obtained. Parallel along the circle. Each protrusion 40 has a rotation allowing surface 40a that comes into contact with the other end 24b of the coil spring 24 so as to be relatively slidable when the plug 18 is screwed into the housing 5, and a rotation prevention surface that comes into contact with the other end 24b of the coil spring 24 so as not to be relatively displaced when the screw 18 is released. 40b. In the present embodiment, the rotation allowing surface 40a is inclined with respect to the reciprocating movement direction of the support yoke 16 so as to go to the screw release direction of the plug 18 into the housing 5 as it goes from the plug 18 to the support yoke 16. The rotation preventing surface 40 b is along the reciprocating direction of the support yoke 16.
[0020]
The plug 18 is engaged with the other end 24b of the coil spring 24 so that the rotation in the screwing release direction to the housing 5 is restricted. The coil spring 24 has an end 24a around an axis along the reciprocating direction of the support yoke 16. The support yoke 16 is connected to the support yoke 16 so that the rotation of the support yoke 16 is restricted, and the rotation of the support yoke 16 around the axis along the reciprocating direction of the support yoke 16 is restricted. The rotation with respect to the housing 5 around the axis along the direction is restricted. Thereby, the rotation of the plug 18 in the screwing release direction to the housing 5 can be restricted without using a dedicated member such as a lock nut. In the above-described embodiment, rotation of the plug 18 in the screwing direction to the housing 5 can be allowed and the rotation in the screwing releasing direction can be restricted with a simple configuration in which the protrusions 40 are formed on the plug 18.
[0021]
The coil spring 24 is subjected to the action of a rotation blocking force in the screw release direction of the plug 18 into the housing 5 and is elastically deformed radially outward by the force. The dimensions of the coil spring 24 and the holding hole 15 are determined so that the coil spring 24 is pressed against the inner periphery of the holding hole 15 by this elastic deformation. By the coil spring 24 is Installing pushed to the inner circumference of the holding hole 15, the frictional force preventing rotation of the screw-releasing direction to the housing 5 of the plug 18, occurs between the holding hole 15 and the coil spring 24 . Thereby, the rotation of the plug 18 in the screwing release direction can be regulated more reliably.
[0022]
In the above configuration, when the plug 18 is screwed into the housing 5, the coil spring 24 rotates together with the plug 18 with respect to the support yoke 16 due to friction between the rotation allowable surface 40 a of the protrusion 40 of the plug 18 and the other end 24 b of the coil spring 24. The one end 24a of the coil spring 24 moves from the other end side of the groove 30 along the arc to one end side. By contacting the inner surface of one end of the groove 30, further rotation of the coil spring 24 relative to the support yoke 16 is prevented. Thereafter, when the plug 18 is further screwed into the housing 5 until it is pressed against the support yoke 16 and then rotated in the screwing release direction, the rotation preventing surface 40b of the protrusion 40 of the plug 18 and the other end 24b of the coil spring 24 come into contact with each other. Thus, the coil spring 24 rotates together with the plug 18. By this rotation, one end 24a of the coil spring 24 moves from one end side of the groove 30 along the arc to the other end side. Since one end 24 a of the coil spring 24 is in contact with the inner surface of the groove 30 on the other end side of the groove 30, the plug 18 can be prevented from rotating in the unscrewing direction via the coil spring 24.
[0023]
The dimension along the arc direction of the groove 30 is set so that the amount of rotation of the coil spring 24 that rotates in the screwing release direction together with the plug 18 screwed in until it is pressed against the support yoke 16 becomes a set amount. Therefore, the interval δ between the support yoke 16 and the plug 18, that is, the stroke of the reciprocating movement of the support yoke 16 can be set according to the set amount. As a result, the backlash amount can be kept within the tolerance range without measuring the backlash amount at the meshing portion of the rack 7 and the pinion 6 during assembly, and the assembly can be facilitated. Since the amount of rotation of the coil spring 24 that rotates in the screw release direction together with the plug 18 varies depending on the interval between the projections 40, the interval between the projections 40 is set so that the backlash can be within the tolerance range. Determine.
[0024]
The present invention is not limited to the above embodiments. For example, the shape of the rotation allowance surface 40 a and the rotation prevention surface 40 b of the protrusion 40 is not limited to the above embodiment, and the rotation allowance surface 40 a is relative to the other end 24 b of the coil spring 24 when the plug 18 is screwed into the housing 5. The rotation preventing surface 40b only needs to be able to slide and to be in contact with the other end 24b of the coil spring 24 so as not to be relatively displaced when the screw is released.
[0025]
【The invention's effect】
According to the present invention, it is possible to provide a rack and pinion type steering device capable of reducing the number of parts and facilitating assembly.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a rack and pinion type steering apparatus according to an embodiment of the present invention. FIG. 2 is a front view of a rack and pinion type steering apparatus according to an embodiment of the present invention. 4 is a sectional view taken along the line IV-IV in FIG. 1. FIG. 5 is a side view of the plug according to the embodiment of the present invention. FIG. 6 is a sectional view taken along the line VI-VI in FIG.
5 Housing 6 Pinion 7 Rack 15 Holding Hole 16 Support Yoke (Rack Support Member)
18 Plug (closing member)
24 Coil spring 30 Groove 40 Projection 40a Rotation allowance surface 40b Rotation prevention surface

Claims

A pinion rotating by steering,
A rack meshing with the pinion,
A housing covering the rack;
A rack support member inserted into a holding hole provided in the housing so as to be reciprocally movable in a direction close to and away from the rack;
A closing member screwed onto the housing by rotation about an axis along the reciprocating direction of the rack support member so as to close the opening on one end side of the holding hole;
A compression coil spring sandwiched between the rack support member and the closing member;
The coil spring gives the rack support member elasticity toward the back of the rack,
The rack support member is restricted from rotating about the axis along the reciprocation direction of the rack support member relative to the rack, and the rack is rotated about the axis along the reciprocation direction of the rack support member relative to the housing. In the rack and pinion type steering device in which
One end of the coil spring is connected to the rack support member so that rotation around the axis along the reciprocating direction of the rack support member is restricted,
A rotation-accepting surface and a rotation-preventing surface that rotate with the closing member;
The rotation allowing surface is slidably contacted with the other end of the coil spring when the closing member is screwed into the housing so that rotation of the closing member into the housing is allowed.
The rotation prevention surface is in contact with the other end of the coil spring so as not to be relatively displaceable when the closing member is released from being screwed into the housing so that the rotation of the closing member into the housing is restricted. Rack and pinion type steering device.

As the coil spring, said the rotation inhibiting force in the screwing direction of releasing the housing closure member radially outward by elastic deformation, rack and pinion according to claim 1 is Installing pushed to the inner circumference of the holding hole Steering device.

A plurality of protrusions protruding into the holding hole from the inner end of the closing member are provided,
The protrusions follow a circle at the center of the axis along the reciprocating direction of the rack support member so that the protrusions can be sequentially brought into contact with the other end of the coil spring by rotating together with the closing member in the screwing direction with respect to the housing. Parallel,
Each projection rack-pinion type steering apparatus according to claim 1 or 2 having said rotation preventing surface and the rotation permitting surface.

The stroke of the reciprocating movement of the rack support member corresponds to the interval between the rack support member and the closing member,
A groove into which one end of the coil spring is movably inserted is formed along the arc on the rack support member side, and one end of the coil spring contacts the inner surface on one end side of the groove, so that the coil spring is in contact with the rack support member. The rotation of the closing member into the housing is prevented, and one end of the coil spring is in contact with the inner surface of the other end of the groove so that the coil spring is in the direction of releasing the screw of the closing member into the housing with respect to the rack support member. The rotation is blocked,
The dimension along the arc of the groove is set so that the coil spring can be rotated by a set amount in the unscrewing direction together with the closing member screwed into the housing until pressed against the support member. The rack and pinion type steering device according to any one of the preceding claims.