JP4161724B2

JP4161724B2 - Vehicle steering system

Info

Publication number: JP4161724B2
Application number: JP2003020053A
Authority: JP
Inventors: 良平葉山; 武夫飯野; 尚武神田
Original assignee: JTEKT Corp
Current assignee: JTEKT Corp
Priority date: 2003-01-29
Filing date: 2003-01-29
Publication date: 2008-10-08
Anticipated expiration: 2023-01-29
Also published as: JP2004230975A

Description

【０００１】
【発明の属する技術分野】
本発明は、操作部材を車輪に機械的に連結することなく、操作部材の操作に応じて舵角を変化させることができる所謂ステアバイワイヤシステムを採用した車両用操舵装置に関する。
【０００２】
【従来の技術】
ステアバイワイヤシステムを採用した操舵装置においては、ステアリングホイールを模した操作部材を車輪に機械的に連結することなく、操舵用アクチュエータの動きを舵角変化が生じるように車輪に伝達している。そのように操作部材を車輪に機械的に連結しない場合、セルフアライニングトルクにより操作部材を直進操舵位置に復帰させることができない。そのため、操作用アクチュエータを用いて操作部材を直進操舵位置に復帰させている。
【０００３】
そのような操作用アクチュエータが故障した時の操作部材の異常な動きを防止するため、操作用アクチュエータの異常検知手段を設け、異常検知時に操作用アクチュエータの発生力の操作部材への作用を解除するフェールセーフ手段が必要になる。しかし、操作用アクチュエータの発生力の操作部材への作用を解除すると、操作部材を自動的に直進操舵位置に復帰させることができなくなる。そこで、操作部材を直進操舵位置に復帰させる弾力を発生する弾性部材を備えた弾力付与機構を設けることが考えられる（特許文献１参照）。
【０００４】
【特許文献１】
特開２０００−５３００８号公報
【０００５】
【発明が解決しようとする課題】
しかし、従来の弾力付与機構は操作部材に弾力を常時作用させる構造であった。すなわち、操作用アクチュエータの異常時だけでなく正常時にも弾力が操作部材に作用する。そのため、車速等の車両走行条件に応じた力が操作部材に作用するように操作用アクチュエータを制御する際に、操作用アクチュエータの応答性が弾力の影響により低下し、操舵フィーリングが低下するという問題がある。
本発明は上記問題を解決することのできる車両用操舵装置を提供することを目的とする。
【０００６】
【課題を解決するための手段】
本発明の車両用操舵装置は、操作部材と、前記操作部材に作用する力を発生する操作用アクチュエータと、操舵用アクチュエータと、前記操舵用アクチュエータの動きを、前記操作部材を車輪に機械的に連結することなく、舵角変化が生じるように前記車輪に伝達する機構と、前記操作部材の操作に応じて前記操作用アクチュエータと前記操舵用アクチュエータを制御する制御装置と、前記操作用アクチュエータの異常検知手段と、その異常検知時に前記操作用アクチュエータの発生力の操作部材への作用を解除する手段と、前記操作部材を直進操舵位置に復帰させる弾力を発生する弾力付与機構と、前記操作部材への前記弾力の作用を、前記異常検知までは阻止すると共に前記異常検知時に阻止解除する弾力制御機構とを備える。
本発明によれば、操作用アクチュエータの異常時に操作部材を弾力により直進操舵位置に復帰させることができ、しかも、その弾力は操作用アクチュエータの正常時には操作部材に作用することがない。これにより、正常時における操作用アクチュエータの応答性が弾力の影響を受けることはない。
【０００７】
前記弾力制御機構は、流体を封入する封入室と、前記流体を前記異常検知までは封入状態に保持すると共に前記異常検知時に封入解除する封入解除機構と、前記封入室における流体容積の変化に応じて変位する弾力規制部材とを有し、前記弾力規制部材は、前記流体の封入状態では前記操作部材への前記弾力の作用の阻止位置に位置され、前記封入状態からの流体の封入解除により、前記操作部材への前記弾力の作用の阻止位置から阻止解除位置に変位されるのが好ましい。
これにより、操作用アクチュエータの異常がない時は、弾力規制部材が弾力の作用の阻止位置から阻止解除位置に変位するのを、流体を封入しておくだけで阻止できる。そして、操作用アクチュエータの異常検知時に、封入室における流体の封入を解除するだけで、操作部材への弾力の作用阻止を解除できる。すなわち、操作部材への弾力の作用阻止と、作用阻止状態から作用状態への変位を、その弾力の大きさに影響されることなく、流体の封入と封入解除だけで行うことができる。よって、その弾力の作用の阻止と阻止解除のための構造をコンパクト化でき、また、大きなエネルギー消費を必要としない。
【０００８】
前記流体は、前記封入室に圧縮状態で封入されると共に前記封入解除により膨張するのが好ましい。
これにより、弾力規制部材が弾力の作用の阻止位置から阻止解除位置に変位するのを、弾力だけでなく流体圧力も利用して行うことができ、円滑な変位が可能になる。しかも、その流体圧力の設定に応じて弾力規制部材の変位速度を任意に設定することが可能になる。
この場合、前記圧縮状態の流体は前記封入室から絞り通路を介して排出されることで膨張するのが好ましい。
これにより、操作部材への弾力の作用阻止状態から作用状態への移行時に、圧縮状態の流体の急激な膨張を抑制し、衝撃が作用するのを防止できる。
【０００９】
【発明の実施の形態】
図１に示す車両用操舵装置は、ステアリングホイールを模した操作部材１と、操舵用アクチュエータ２と、操舵用アクチュエータ２の動きを、操作部材１を車輪４に機械的に連結することなく舵角変化が生じるように車輪４に伝達するステアリングギヤ機構３とを備える。
【００１０】
操舵用アクチュエータ２はブラシレスモータ等の電動モータにより構成できる。ステアリングギヤ機構３は、操舵用アクチュエータ２の回転運動をステアリングロッド７の直線運動に変換する運動変換機構を有し、その運動変換機構は例えば操舵用アクチュエータ２により回転駆動されるボールナットにねじ合わされるボールスクリューをステアリングロッド７と一体的に設けることで構成される。ステアリングロッド７の動きがタイロッド８とナックルアーム９を介して車輪４に伝達されることで車輪４のトー角が変化する。ステアリングギヤ機構３は公知のものを用いることができ、操舵用アクチュエータ２の動きを舵角が変化するように車輪４に伝達できれば構成は限定されない。操舵用アクチュエータ２が駆動されていない状態では、車輪４はセルフアライニングトルクにより直進位置に復帰できるようにホイールアラインメントが設定されている。
【００１１】
操作部材１は、車体側により回転可能に支持される入力側回転シャフト１０に同行回転するように連結されている。入力側回転シャフト１０に操作用アクチュエータ１９の出力シャフトが一体化されている。操作用アクチュエータ１９は操作部材１に作用する力を発生し、ブラシレスモータ等の電動モータにより構成される。
【００１２】
操作部材１の操作角δｈを検出する角度センサ１１、操作トルクＴｈとして入力側回転シャフト１０により伝達されるトルクを検出するトルクセンサ１２、車速Ｖを検出する速度センサ１３、舵角δとしてステアリングロッド７の移動量を検出する舵角センサ１４が、コンピュータにより構成される制御装置２０に接続されている。その制御装置２０は操作部材１の操作に応じて操舵用アクチュエータ２と操作用アクチュエータ１９を制御する。
【００１３】
操作用アクチュエータ１９の異常検知手段が設けられている。本実施形態では、制御装置２０が目標操作トルクＴｈ^* と検出操作トルクＴｈとの偏差をモニターし、その偏差が設定値以上であれば操作用アクチュエータ１９が異常であると判断する。その異常検知時に制御装置２０は操作用アクチュエータ１９への電力供給を遮断し、操作用アクチュエータ１９の発生力の操作部材１への作用を解除する。
【００１４】
操作部材１を直進操舵位置に復帰させる弾力を発生する弾力付与機構３０が設けられている。図２に示すように、弾力付与機構３０は、操作用アクチュエータ１９のケーシングに一体化されるハウジング３２により、回転シャフト１０に一体化されるボールスクリューシャフト３１を覆う。ハウジング３２の一端側に筒状の第１ストッパー３３が圧入固定され、他端側に筒状の第２ストッパー３４が圧入固定される。スクリューシャフト３１にボール３８を介してボールナット３９がねじ合わされ、ボールナット３９は筒状ガイド部材４０に圧入固定される。第１ストッパー３３の内周３３ａ、第２ストッパー３４の内周３４ａおよびガイド部材４０の両端外周４０ａ、４０ｂは多角形あるいは非円形とされ、ガイド部材４０は第１ストッパー３３および第２ストッパー３４に軸方向移動可能かつ相対回転不能に嵌め合わされる。これにより、操作部材１の操作によるボールスクリューシャフト３１の回転により、ボールナット３９と共にガイド部材４０は軸方向移動する。ガイド部材４０の外周に筒状の第１、第２スライダー４１、４２が軸方向相対移動可能に嵌め合わされ、両スライダー４１、４２の間において弾性部材である圧縮コイルバネ４３がガイド部材４０に嵌め合わされている。ガイド部材４０の外周に両スライダー４１、４２の抜け止め用段差４０ｃ、４０ｄが設けられている。第１スライダー４１は一端外周から外方に伸びる受け部４１ａを有し、受け部４１ａは第１ストッパー３３の第１ストッパー面３３ｃに対向する。第２スライダー４２は他端外周から外方に伸びる受け部４２ａを有し、受け部４２ａは第２ストッパー３４の第２ストッパー面３４ｃに対向する。
【００１５】
図２は、操作部材１が直進操舵位置にある時の状態を示す。この時、バネ４３の弾力により第１スライダー４１は第１ストッパー面３３ｃに押し付けられ、第２スライダー４２は第２ストッパー面３４ｃに押し付けられる。
【００１６】
左操舵によるボールスクリューシャフト３１の回転により、ボールナット３９と共にガイド部材４０は図において下方に向かい軸方向移動する。すると、図３に示すように、ガイド部材４０と同行して第１スライダー４１は軸方向移動し、第２スライダー４２は第２ストッパー面３４ｃにより軸方向移動を阻止される。これにより、バネ４３は圧縮されるので、ガイド部材４０を図において上方に向かい軸方向移動させようとする弾力が作用する。すなわち、操作部材１を直進操舵位置に復帰させる弾力が付与される。
また、右操舵によるボールスクリューシャフト３１の回転により、ボールナット３９と共にガイド部材４０は図において上方に向かい軸方向移動する。すると、図４に示すように、ガイド部材４０と同行して第２スライダー４２は軸方向移動し、第１スライダー４１は第１ストッパー面３３ｃにより軸方向移動を阻止される。これにより、バネ４３は圧縮されるので、ガイド部材４０を図において下方に向かい軸方向移動させようとする弾力が作用する。すなわち、操作部材１を直進操舵位置に復帰させる弾力が付与される。
【００１７】
図５に示すように、操作部材１への上記弾力の作用を、操作用アクチュエータ１９の異常検知までは阻止すると共に異常検知時に阻止解除する弾力制御機構５０が設けられている。図６に示すように、本実施形態の弾力制御機構５０は車体側に取り付けられた一対のガスシリンダ５０ａと、制御装置２０に接続された一対の電磁開閉バルブ５９により構成される封入解除機構とを有する。各ガスシリンダ５０ａにおいては、シリンダチューブ５１内にピストン５２により区画される一対の封入室５３、５４が設けられ、両封入室５３、５４はバイパス通路５５により連絡される。バイパス通路５５は絞り通路とされている。ピストン５２に一体化されたピストンロッド５６がシリンダチューブ５１の外部に突出する。ピストン５２の受圧面積は一方の封入室５３では他方の封入室５４におけるよりも大きくされている。バイパス通路５５が電磁開閉バルブ５９により開閉される。両封入室５３、５４に流体としてガスが封入される。ガスの種類は限定されず、本実施形態では空気が封入される。一方のガスシリンダ５０ａのピストンロッド５６に取り付けられた第１規制部材５７ａが、ハウジング３２内に開口３２ａから挿入され、バネ４３の一端と第１スライダー４１の受け部４１ａとの間に配置された第１弾力規制部材５８ａに連結されている。他方のガスシリンダ５０ａのピストンロッド５６に取り付けられた第２規制部材５７ｂが、ハウジング３２内に開口３２ｂから挿入され、バネ４３の他端と第２スライダー４２の受け部４２ａとの間に配置された第２弾力規制部材５８ｂに連結されている。
【００１８】
操作用アクチュエータ１９の異常検知までは、各ピストンロッド５６は縮小状態とされ、他方の封入室５４にガスは圧縮状態で封入されている。この状態では、図５に示すように両弾力規制部材５８ａ、５８ｂは操作部材１への弾力の作用の阻止位置に位置され、バネ４３は両弾力規制部材５８ａ、５８ｂにより圧縮され、弾力は各スライダー４１、４２に作用されない。制御装置２０は操作用アクチュエータ１９の異常検知時に電磁開閉バルブ５９に開信号を送る。これにより、他方の封入室５４のガスは膨張してバイパス通路５５を介して一方の封入室５３に流動する。すなわち、封入解除機構は異常検知までは他方の封入室５４におけるガスを封入状態に保持すると共に異常検知時に封入解除させる。このガスの封入解除により、バネ４３の弾力と、一方の封入室５３と他方の封入室５４とで受圧面積に差があるピストン５２に作用するガス圧力とにより、各ピストンロッド５６は伸長する。すなわち、封入室５３におけるガス容積の変化に応じて弾力規制部材５８ａ、５８ｂは変位し、ガスの封入状態では操作部材１への弾力の作用の阻止位置に位置され、封入状態からのガスの封入解除により、操作部材１への弾力の作用の阻止位置から阻止解除位置に変位される。本実施形態では、その封入解除により図２〜図４に示すように両弾力規制部材５８ａ、５８ｂはスライダー４１、４２に押し付けられ、操作部材１への弾力の作用の阻止位置から阻止解除位置に変位され、バイパス通路５５により構成される絞り通路を介して圧縮状態のガスは他方の封入室５４から排出されることで膨張する。
【００１９】
図７のフローチャートは制御装置２０による両アクチュエータ２、１９の制御手順を示す。まず、例えばイグニッションスイッチのオンによる制御装置２０への電力供給により制御が開始されると、各センサによる検出データを読み込み（ステップＳ１）、操作部材１の検出操作角θｈと検出車速Ｖに応じた目標舵角θ^* を記憶した関係θ^* ＝Ｇ１（θｈ、Ｖ）から求め（ステップＳ２）、目標舵角θ^* と実舵角θとの偏差が低減されるように操舵用アクチュエータ２をフィードバック制御する（ステップＳ３）。その記憶される関係θ^* ＝Ｇ１（θｈ、Ｖ）は、例えば操作角θｈが大きく車速Ｖが小さい程に目標舵角θ^* が大きくなるように予め定められる。次に、異常フラグがオンか否かを判断し（ステップＳ４）、オンでなければ操作用アクチュエータ１９の異常が検知されたか否かを判断する（ステップＳ５）。ステップＳ５において異常が検知されていれば、異常フラグをオンし（ステップＳ６）、操作用アクチュエータ１９への電力供給を遮断して操作用アクチュエータ１９の発生力の操作部材１への作用を解除し、また、電磁開閉バルブ５９に開信号を送ることでフェールセーフ処理を行う（ステップＳ７）。次に、制御を終了するか否かを例えば車両のイグニッションスイッチがオンか否かにより判断し（ステップＳ８）、終了する場合は異常フラグをオフし（ステップＳ９）、しかる後に終了し、終了しない場合はステップＳ１に戻る。ステップＳ５において異常が検知されていなければ、操作部材１の検出操作角θｈと検出車速Ｖに応じた目標操作トルクＴｈ^* を記憶した関係Ｔｈ^* ＝Ｇ２（θｈ、Ｖ）から求め（ステップＳ１０）、目標操作トルクＴｈ^* と検出操作トルクＴｈとの偏差を低減するように操作用アクチュエータ１９をフィードバック制御する（ステップＳ１１）。その記憶される関係Ｔｈ^* ＝Ｇ２（θｈ、Ｖ）は、例えば操作角θｈが大きく車速Ｖが小さい程に目標操作トルクＴｈ^* が小さくなるように予め定められる。しかる後に制御を終了するか否かを判断する。
【００２０】
上記実施形態によれば、操作用アクチュエータ１９の異常時に操作部材１をバネ４３の弾力により直進操舵位置に復帰させることができ、しかも、その弾力は操作用アクチュエータ１９の正常時には操作部材１に作用することがない。これにより、正常時における操作用アクチュエータ１９の応答性が弾力の影響を受けることはない。また、操作用アクチュエータ１９の異常がない時は、弾力規制部材５８ａ、５８ｂが弾力の作用の阻止位置から阻止解除位置に変位するのを、流体を封入しておくだけで阻止できる。そして、操作用アクチュエータ１９の異常検知時に、封入室５４におけるガスの封入を解除するだけで、操作部材１への弾力の作用阻止を解除できる。すなわち、操作部材１への弾力の作用阻止と、作用阻止状態から作用状態への変位を、その弾力の大きさに影響されることなく、流体の封入と封入解除だけで行うことができる。よって、その弾力の作用の阻止と阻止解除を、例えば大容量の電磁クラッチ等を要することなく行うことができるので構造をコンパクト化でき、また、大きなエネルギー消費を必要としない。また、封入室５４においてガスは圧縮状態で封入されるので、弾力規制部材５８ａ、５８ｂが弾力の作用の阻止位置から阻止解除位置に変位するのを、弾力だけでなくガス圧力も利用して行うことができ、円滑な変位が可能になる。しかも、そのガス圧力の設定に応じて弾力規制部材５８ａ、５８ｂの変位速度を任意に設定することが可能になる。さらに、圧縮状態のガスはバイパス通路５５により構成される絞り通路を介して封入室５４から排出されるので、操作部材１への弾力の作用阻止状態から作用状態への移行時に、圧縮状態のガスの急激な膨張を抑制し、衝撃が作用するのを防止できる。
【００２１】
図８、図９は本発明の第１変形例を示し、上記実施形態と異なる弾力付与機構１３０と弾力制御機構１５０を備える。
弾力付与機構１３０は、車体に支持された第２回転シャフト７０と、第２回転シャフト７０に嵌め合わされた一対のつるまきバネ７１ａ、７１ｂと、回転シャフト１０と第２回転シャフト７０との間で回転を伝達するギヤ機構７２を備える。各バネ７１ａ、７１ｂの一端は車体側に設けられた受け部７２ａ、７２ｂに押し付けられる。各バネ７１ａ、７１ｂの他端側は、弾力制御機構１５０により操作部材１への弾力の作用を阻止されていない時、図９において破線で示すように第２回転シャフト７０に設けられた押し付け部７０ａに接する。これにより、左右一方への操舵による操作部材１の回転により第２回転シャフト７０が一方向に回転すると、一方のバネ７１ａが押し付け部７０ａに押し付けられることで弾性変形し、操作部材１を直進操舵位置に復帰させる弾力を発生する。また、左右他方への操舵による操作部材１の回転により第２回転シャフト７０が他方向に回転すると、他方のバネ７１ｂが押し付け部７０ａに押し付けられることで弾性変形し、操作部材１を直進操舵位置に復帰させる弾力を発生する。
弾力制御機構１５０は、上記実施形態のガスシリンダ５０ａと同様の車体側に取り付けられたガスシリンダ（図示省略）と、上記実施形態の電磁開閉バルブ５９と同様の制御装置に接続された電磁開閉バルブにより構成される封入解除機構とを有する。ガスシリンダのピストンロッド５６はワイヤ等の可撓性索体により構成される弾力規制部材１５８ａ、１５８ｂを介して両バネ７１ａ、７１ｂの他端側に連結され、弾力規制部材１５８ａ、１５８ｂは車体側に取り付けられたプーリ７４ａ、７４ｂに引っ掛けられている。
操作用アクチュエータ１９の異常検知までは、ピストンロッド５６は縮小状態とされ、図９において１点鎖線で示すように弾力規制部材１５８ａ、１５８ｂは操作部材１への弾力の作用の阻止位置に位置され、両バネ７１ａ、７１ｂの他端側は実線で示すように押し付け部７０ａと接することのない位置に配置される。制御装置２０が操作用アクチュエータ１９の異常検知時に電磁開閉バルブに開信号を送ることでピストンロッド５６が伸長し、弾力規制部材１５８ａは図において破線で示す操作部材１への弾力の作用の阻止解除位置に変位され、各バネ７１ａ、７１ｂの他端側は押し付け部７０ａに接する。他は上記実施形態と同様で、同様部分は同一符号で示す。
【００２２】
図１０は本発明の第２変形例を示し、第１変形例と同様の弾力付与機構１３０と、上記実施形態および第１変形例と異なる弾力制御機構２５０を備える。
弾力制御機構２５０は、車体側に取り付けられた一対のガスシリンダ２５０ａと、制御装置２０に接続された一対の電磁開閉バルブ２６０により構成される封入解除機構とを有する。両ガスシリンダ２５０ａの間に両バネ７１ａ、７１ｂが配置される。各ガスシリンダ２５０ａにおいては、シリンダチューブ２５１の内面とピストン２５２の受圧面により囲まれる封入室２５３が設けられ、ピストン２５２に一体化されたピストンロッド２５６の先端に弾力規制部材２５８が取り付けられている。封入室２５３は電磁開閉バルブ２６０を介して大気開放口２５５に通じる。
操作用アクチュエータ１９の異常検知までは、封入室２５３に圧縮状態に保持された高圧ガスが封入され、各ピストンロッド２５６は伸長状態とされる。この状態では、両弾力規制部材２５８は操作部材１への弾力の作用の阻止位置に位置され、図において実線で示すように両バネ７１ａ、７１ｂの他端に取り付けられたプーリ２５９に接し、これにより、両バネ７１ａ、７１ｂの他端側は押し付け部７０ａと接することのない位置に配置される。制御装置２０が操作用アクチュエータ１９の異常検知時に電磁開閉バルブ２６０に開信号を送ることで、封入室２５３に封入されたガスが大気中に放出されることで膨張し、これによりバネ７１ａ、７１ｂの弾力により各ピストンロッド２５６は縮小し、弾力規制部材２５８が操作部材１への弾力の作用の阻止解除位置に変位され、各バネ７１ａ、７１ｂの他端側は図１０において破線で示すように押し付け部７０ａに接することで操作部材１を直進操舵位置に復帰させる弾力を発生する。他は上記実施形態および第１変形例と同様で同様部分は同一符号で示す。
【００２３】
図１１は本発明の第３変形例を示し、第１変形例と同様の弾力付与機構１３０と、上記実施形態および第１、第２変形例と異なる弾力制御機構３５０を備える。弾力制御機構３５０は、上記実施形態と同様の車体側に取り付けられた一対のガスシリンダ５０ａと、各ガスシリンダ５０ａそれぞれの両封入室を連絡するバイパス通路を開閉する上記実施形態と同様の一対の電磁開閉バルブ５９を有し、両ガスシリンダ５０ａは両バネ７１ａ、７１ｂの他端間に配置される。各ガスシリンダ５０ａのピストンロッド５６の先端はフック状に曲げられ、その先端に第２変形例と同様の弾力規制部材２５８が取り付けられている。
操作用アクチュエータ１９の異常検知までは、両ピストンロッド５６は縮小状態とされる。この状態では、両弾力規制部材２５８は操作部材１への弾力の作用の阻止位置に位置され、図において実線で示すように両バネ７１ａ、７１ｂの他端に取り付けられたプーリ２５９に接し、これにより、両バネ７１ａ、７１ｂの他端側は押し付け部７０ａと接することのない位置に配置される。制御装置２０が操作用アクチュエータ１９の異常検知時に各電磁開閉バルブ５９に開信号を送ることで各ピストンロッド５６は伸長し、これにより弾力規制部材２５８は操作部材１への弾力の作用の阻止解除位置に変位され、各バネ７１ａ、７１ｂの他端側は図１１において破線で示すように押し付け部７０ａに接することで操作部材１を直進操舵位置に復帰させる弾力を発生する。他は上記実施形態および第１、第２変形例と同様で同様部分は同一符号で示す。
【００２４】
上記実施形態や変形例においては封入室に流体としてガスを封入したが、これに代えて液体を封入してもよく、また、封入室に封入される流体は圧縮しなくてもよい。例えば第４変形例として、上記実施形態における各封入室５３、５４にガスに代えて油を圧縮することなく封入し、他は上記実施形態と同様に構成してもよい。
【００２５】
本発明は上記実施形態や変形例に限定されない。例えば、操作部材を直進操舵位置に復帰させる弾力を、異なるタイプのバネやゴム等により発生させてもよい。
【００２６】
【発明の効果】
本発明によれば、ステアバイワイヤシステムを採用した車両用操舵装置において、フィーリングを低下させることなく、コンパクトな構造で、大きなエネルギーを消費することなく、さらに衝撃を与えることなく、操作用アクチュエータの異常時に、操作部材を直進操舵位置に復帰させる弾力を作用させることでフェールセーフ機能を奏することができる。
【図面の簡単な説明】
【図１】本発明の実施形態の車両用操舵装置の構成説明図
【図２】本発明の実施形態の車両用操舵装置における操作用アクチュエータの異常検知時の直進操舵状態での弾力付与機構の断面図
【図３】本発明の実施形態の車両用操舵装置における操作用アクチュエータの異常検知時の左操舵状態での弾力付与機構の断面図
【図４】本発明の実施形態の車両用操舵装置における操作用アクチュエータの異常検知時の右操舵状態での弾力付与機構の断面図
【図５】本発明の実施形態の車両用操舵装置における弾力制御機構の構成説明図
【図６】本発明の実施形態の車両用操舵装置における弾力制御機構の要部の構成説明図
【図７】本発明の実施形態の車両用操舵装置における操作用アクチュエータと操舵用アクチュエータの制御手順を示すフローチャート
【図８】本発明の第１変形例の車両用操舵装置における弾力付与機構の配置説明図
【図９】本発明の第１変形例の車両用操舵装置における弾力付与機構と弾力制御機構の構成説明図
【図１０】本発明の第２変形例の車両用操舵装置における弾力付与機構と弾力制御機構の構成説明図
【図１１】本発明の第３変形例の車両用操舵装置における弾力付与機構と弾力制御機構の構成説明図
【符号の説明】
１操作部材
２操舵用アクチュエータ
３ステアリングギヤ機構
４車輪
１９操作用アクチュエータ
２０制御装置
３０、１３０弾力付与機構
５０、１５０、２５０、３５０弾力制御機構
５０ａガスシリンダ（封入解除機構）
５３、５４封入室
５５バイパス通路（絞り通路）
５８ａ第１弾力規制部材
５８ｂ第２弾力規制部材
５９電磁開閉バルブ（封入解除機構）
１５８ａ、２５８弾力規制部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle steering apparatus that employs a so-called steer-by-wire system that can change a rudder angle according to an operation of an operation member without mechanically connecting the operation member to a wheel.
[0002]
[Prior art]
In a steering device that employs a steer-by-wire system, an operation member that imitates a steering wheel is mechanically connected to the wheel, and the movement of the steering actuator is transmitted to the wheel so that the steering angle changes. When the operating member is not mechanically connected to the wheel as described above, the operating member cannot be returned to the straight steering position by the self-aligning torque. Therefore, the operating member is returned to the straight steering position using the operating actuator.
[0003]
In order to prevent an abnormal movement of the operation member when such an operation actuator fails, an abnormality detection means for the operation actuator is provided, and the action of the generated force of the operation actuator on the operation member is canceled when an abnormality is detected. Fail-safe measures are needed. However, if the action of the generated force of the operating actuator on the operating member is released, the operating member cannot be automatically returned to the straight steering position. In view of this, it is conceivable to provide an elastic force applying mechanism including an elastic member that generates an elastic force for returning the operation member to the straight steering position (see Patent Document 1).
[0004]
[Patent Document 1]
JP 2000-53008 A
[0005]
[Problems to be solved by the invention]
However, the conventional elasticity applying mechanism has a structure in which elasticity is always applied to the operation member. That is, the elasticity acts on the operation member not only when the operation actuator is abnormal but also when it is normal. Therefore, when the operation actuator is controlled so that a force according to the vehicle traveling condition such as the vehicle speed acts on the operation member, the responsiveness of the operation actuator is reduced due to the influence of elasticity, and the steering feeling is reduced. There's a problem.
It is an object of the present invention to provide a vehicle steering apparatus that can solve the above problems.
[0006]
[Means for Solving the Problems]
The vehicle steering apparatus according to the present invention includes an operation member, an operation actuator that generates a force acting on the operation member, a steering actuator, and a movement of the steering actuator, mechanically using the operation member as a wheel. A mechanism for transmitting to the wheel so that a steering angle change occurs without being connected, a control device for controlling the operating actuator and the steering actuator according to an operation of the operating member, and an abnormality in the operating actuator Detecting means, means for releasing the action of the generated force of the operating actuator on the operating member when the abnormality is detected, an elasticity applying mechanism for generating elasticity for returning the operating member to the straight steering position, and the operating member An elastic force control mechanism that blocks the action of the elastic force until the abnormality is detected and releases the blocking when the abnormality is detected.
According to the present invention, when the operating actuator is abnormal, the operating member can be returned to the straight-ahead steering position by elasticity, and the elasticity does not act on the operating member when the operating actuator is normal. As a result, the response of the operating actuator during normal operation is not affected by elasticity.
[0007]
The elasticity control mechanism includes a sealing chamber that encloses a fluid, a sealing release mechanism that holds the fluid in a sealed state until the abnormality is detected and releases the sealing when the abnormality is detected, and a change in fluid volume in the sealing chamber. The elastic force restricting member is located at a position where the elastic member is prevented from acting on the operation member when the fluid is sealed, and by releasing the fluid from the sealed state, It is preferable that the elastic member is displaced from a blocking position of the elastic force to the operating member to a blocking release position.
As a result, when there is no abnormality in the operating actuator, it is possible to prevent the elasticity regulating member from being displaced from the position where the elasticity is prevented to the position where the elasticity is released by simply sealing the fluid. Then, when an abnormality is detected in the operation actuator, it is possible to cancel the blocking of the action of the elastic force on the operation member only by releasing the fluid from the enclosure chamber. That is, it is possible to prevent the action of the elastic force on the operation member and to change the action from the action-prevented state to the action state by only enclosing and releasing the fluid without being influenced by the magnitude of the elastic force. Therefore, the structure for preventing and releasing the elastic action can be made compact, and no large energy consumption is required.
[0008]
It is preferable that the fluid is sealed in the sealed chamber in a compressed state and expands when the sealed state is released.
As a result, the elasticity regulating member can be displaced from the elasticity inhibiting position to the inhibition releasing position by utilizing not only the elasticity but also the fluid pressure, thereby enabling smooth displacement. Moreover, it is possible to arbitrarily set the displacement speed of the elastic force regulating member according to the setting of the fluid pressure.
In this case, it is preferable that the compressed fluid expands by being discharged from the sealing chamber through the throttle passage.
Thereby, at the time of the transition from the action inhibition state of the elastic force to the operation member to the action state, it is possible to suppress rapid expansion of the fluid in the compressed state and to prevent an impact from acting.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The vehicle steering apparatus shown in FIG. 1 operates the operation member 1 simulating a steering wheel, the steering actuator 2, and the movements of the steering actuator 2 without mechanically connecting the operation member 1 to the wheels 4. And a steering gear mechanism 3 that transmits to the wheels 4 so that a change occurs.
[0010]
The steering actuator 2 can be constituted by an electric motor such as a brushless motor. The steering gear mechanism 3 has a motion conversion mechanism that converts the rotational motion of the steering actuator 2 into the linear motion of the steering rod 7, and the motion conversion mechanism is screwed onto a ball nut that is rotationally driven by the steering actuator 2, for example. The ball screw is provided integrally with the steering rod 7. The movement of the steering rod 7 is transmitted to the wheel 4 through the tie rod 8 and the knuckle arm 9 so that the toe angle of the wheel 4 changes. As the steering gear mechanism 3, a known one can be used, and the configuration is not limited as long as the movement of the steering actuator 2 can be transmitted to the wheels 4 so that the steering angle changes. In a state where the steering actuator 2 is not driven, the wheel alignment is set so that the wheel 4 can return to the straight position by the self-aligning torque.
[0011]
The operation member 1 is connected to an input side rotation shaft 10 rotatably supported by the vehicle body side so as to rotate together. An output shaft of the operation actuator 19 is integrated with the input side rotating shaft 10. The operation actuator 19 generates a force acting on the operation member 1 and is constituted by an electric motor such as a brushless motor.
[0012]
An angle sensor 11 for detecting the operation angle δh of the operation member 1, a torque sensor 12 for detecting the torque transmitted by the input side rotary shaft 10 as the operation torque Th, a speed sensor 13 for detecting the vehicle speed V, and a steering rod as the steering angle δ 7 is connected to a control device 20 configured by a computer. The control device 20 controls the steering actuator 2 and the operation actuator 19 in accordance with the operation of the operation member 1.
[0013]
An abnormality detection means for the operation actuator 19 is provided. In the present embodiment, the control device 20 performs the target operation torque Th ^* And the detected operation torque Th are monitored, and if the deviation is equal to or greater than a set value, it is determined that the operation actuator 19 is abnormal. When the abnormality is detected, the control device 20 cuts off the power supply to the operation actuator 19 and cancels the action of the generated force of the operation actuator 19 on the operation member 1.
[0014]
A resilience applying mechanism 30 that generates resilience for returning the operation member 1 to the straight steering position is provided. As shown in FIG. 2, the elasticity applying mechanism 30 covers a ball screw shaft 31 integrated with the rotary shaft 10 by a housing 32 integrated with the casing of the operating actuator 19. A cylindrical first stopper 33 is press-fitted and fixed to one end side of the housing 32, and a cylindrical second stopper 34 is press-fitted and fixed to the other end side. A ball nut 39 is screwed onto the screw shaft 31 via a ball 38, and the ball nut 39 is press-fitted and fixed to the cylindrical guide member 40. The inner periphery 33 a of the first stopper 33, the inner periphery 34 a of the second stopper 34, and the outer ends 40 a and 40 b of both ends of the guide member 40 are polygonal or non-circular, and the guide member 40 is connected to the first stopper 33 and the second stopper 34. They are fitted so that they can move in the axial direction but cannot rotate relative to each other. Thereby, the guide member 40 moves in the axial direction together with the ball nut 39 by the rotation of the ball screw shaft 31 by the operation of the operation member 1. The cylindrical first and second sliders 41 and 42 are fitted to the outer periphery of the guide member 40 so as to be axially movable relative to each other, and a compression coil spring 43 that is an elastic member is fitted between the sliders 41 and 42 to the guide member 40. ing. On the outer periphery of the guide member 40, steps 40c and 40d for preventing the sliders 41 and 42 from coming off are provided. The first slider 41 has a receiving portion 41 a that extends outward from the outer periphery of one end, and the receiving portion 41 a faces the first stopper surface 33 c of the first stopper 33. The second slider 42 has a receiving portion 42 a extending outward from the outer periphery of the other end, and the receiving portion 42 a faces the second stopper surface 34 c of the second stopper 34.
[0015]
FIG. 2 shows a state when the operation member 1 is in the straight steering position. At this time, the first slider 41 is pressed against the first stopper surface 33c by the elasticity of the spring 43, and the second slider 42 is pressed against the second stopper surface 34c.
[0016]
By rotation of the ball screw shaft 31 by left steering, the guide member 40 together with the ball nut 39 moves downward in the drawing in the axial direction. Then, as shown in FIG. 3, the first slider 41 moves in the axial direction along with the guide member 40, and the second slider 42 is prevented from moving in the axial direction by the second stopper surface 34c. As a result, the spring 43 is compressed, and an elastic force is applied to move the guide member 40 upward in the drawing in the axial direction. That is, the elasticity which returns the operation member 1 to a straight steering position is given.
Further, the guide member 40 together with the ball nut 39 moves upward in the drawing in the axial direction by the rotation of the ball screw shaft 31 by the right steering. Then, as shown in FIG. 4, the second slider 42 moves in the axial direction along with the guide member 40, and the first slider 41 is prevented from moving in the axial direction by the first stopper surface 33c. As a result, the spring 43 is compressed, and an elastic force is applied to move the guide member 40 downward in the drawing in the axial direction. That is, the elasticity which returns the operation member 1 to a straight steering position is given.
[0017]
As shown in FIG. 5, an elastic force control mechanism 50 is provided that prevents the operation of the elastic force on the operating member 1 until the abnormality of the operating actuator 19 is detected and releases the blocking when the abnormality is detected. As shown in FIG. 6, the elasticity control mechanism 50 of the present embodiment includes an enclosing release mechanism configured by a pair of gas cylinders 50 a attached to the vehicle body side and a pair of electromagnetic on-off valves 59 connected to the control device 20. Have Each gas cylinder 50 a is provided with a pair of enclosure chambers 53, 54 defined by a piston 52 in the cylinder tube 51, and both enclosure chambers 53, 54 are connected by a bypass passage 55. The bypass passage 55 is a throttle passage. A piston rod 56 integrated with the piston 52 projects outside the cylinder tube 51. The pressure receiving area of the piston 52 is made larger in one sealing chamber 53 than in the other sealing chamber 54. The bypass passage 55 is opened and closed by an electromagnetic opening / closing valve 59. Gas is sealed in both the sealing chambers 53 and 54 as a fluid. The type of gas is not limited, and air is enclosed in this embodiment. A first restricting member 57 a attached to the piston rod 56 of one gas cylinder 50 a is inserted into the housing 32 from the opening 32 a and is disposed between one end of the spring 43 and the receiving portion 41 a of the first slider 41. It is connected to the first elasticity regulating member 58a. A second regulating member 57b attached to the piston rod 56 of the other gas cylinder 50a is inserted into the housing 32 from the opening 32b and is disposed between the other end of the spring 43 and the receiving portion 42a of the second slider 42. The second elasticity regulating member 58b is connected.
[0018]
Until the abnormality of the operating actuator 19 is detected, each piston rod 56 is in a contracted state, and gas is sealed in the other sealed chamber 54 in a compressed state. In this state, as shown in FIG. 5, the both elastic restriction members 58a and 58b are positioned at the position where the elastic force acting on the operation member 1 is prevented, and the spring 43 is compressed by the both elastic restriction members 58a and 58b. The sliders 41 and 42 are not affected. The control device 20 sends an open signal to the electromagnetic opening / closing valve 59 when the abnormality of the operation actuator 19 is detected. As a result, the gas in the other enclosure chamber 54 expands and flows to the one enclosure chamber 53 via the bypass passage 55. That is, the enclosure release mechanism holds the gas in the other enclosure chamber 54 in an enclosed state until abnormality is detected, and releases the enclosure when abnormality is detected. By releasing the sealing of the gas, each piston rod 56 extends due to the elasticity of the spring 43 and the gas pressure acting on the piston 52 having a difference in pressure receiving area between the one sealing chamber 53 and the other sealing chamber 54. That is, the elasticity regulating members 58a and 58b are displaced according to the change in the gas volume in the sealing chamber 53, and are positioned at a position where the elastic force is applied to the operation member 1 when the gas is sealed, and the gas is sealed from the sealed state. Due to the release, the operation member 1 is displaced from the blocking position of the action of elasticity to the blocking release position. In the present embodiment, as shown in FIGS. 2 to 4, the both elastic force restricting members 58 a and 58 b are pressed against the sliders 41 and 42 by the release of the encapsulation, and the elastic force acting on the operation member 1 is changed from the blocking position to the blocking release position. The gas in the compressed state is displaced through the throttle passage constituted by the bypass passage 55 and is expanded by being discharged from the other enclosure chamber 54.
[0019]
The flowchart of FIG. 7 shows the control procedure of the actuators 2 and 19 by the control device 20. First, for example, when control is started by supplying power to the control device 20 when the ignition switch is turned on, detection data from each sensor is read (step S1), and the detection operation angle θh of the operation member 1 and the detected vehicle speed V are determined. Target rudder angle θ ^* The relationship θ memorized ^* = Calculated from G1 (θh, V) (step S2), target steering angle θ ^* The steering actuator 2 is feedback-controlled so that the deviation between the actual steering angle θ and the actual steering angle θ is reduced (step S3). The memorized relationship θ ^* = G1 (θh, V) is, for example, the target steering angle θ as the operation angle θh increases and the vehicle speed V decreases. ^* Is predetermined in advance. Next, it is determined whether or not the abnormality flag is on (step S4). If it is not on, it is determined whether or not an abnormality of the operating actuator 19 has been detected (step S5). If an abnormality is detected in step S5, the abnormality flag is turned on (step S6), the power supply to the operation actuator 19 is cut off, and the action of the generated force of the operation actuator 19 on the operation member 1 is released. Further, a fail-safe process is performed by sending an open signal to the electromagnetic open / close valve 59 (step S7). Next, whether or not to end the control is determined, for example, based on whether or not the ignition switch of the vehicle is on (step S8). If the control is to be ended, the abnormality flag is turned off (step S9). If so, the process returns to step S1. If no abnormality is detected in step S5, the target operation torque Th according to the detected operation angle θh of the operation member 1 and the detected vehicle speed V is determined. ^* Relationship Th remembered ^* = Calculated from G2 (θh, V) (step S10), target operation torque Th ^* And the operation actuator 19 are feedback-controlled so as to reduce the deviation between the detected operation torque Th (step S11). The stored relationship Th ^* = G2 (θh, V) is, for example, the target operation torque Th as the operation angle θh increases and the vehicle speed V decreases. ^* Is predetermined so as to be small. Thereafter, it is determined whether or not to end the control.
[0020]
According to the above embodiment, when the operating actuator 19 is abnormal, the operating member 1 can be returned to the straight steering position by the elasticity of the spring 43, and the elasticity acts on the operating member 1 when the operating actuator 19 is normal. There is nothing to do. As a result, the response of the operating actuator 19 during normal operation is not affected by elasticity. Further, when there is no abnormality in the operation actuator 19, it is possible to prevent the elasticity regulating members 58a and 58b from being displaced from the position where the elasticity is prevented to the position where the elasticity is released by simply enclosing the fluid. Then, when the abnormality of the operation actuator 19 is detected, it is possible to cancel the inhibition of the elastic action on the operation member 1 only by releasing the sealing of the gas in the sealing chamber 54. That is, the action of the elastic force on the operation member 1 and the displacement from the action-blocked state to the action state can be performed only by enclosing and releasing the fluid without being influenced by the magnitude of the elastic force. Therefore, the elastic action can be blocked and released without requiring a large-capacity electromagnetic clutch or the like, so that the structure can be made compact and no large energy consumption is required. In addition, since the gas is sealed in the sealed chamber 54 in a compressed state, the elastic force regulating members 58a and 58b are displaced from the elastic action blocking position to the blocking release position using not only the elasticity but also the gas pressure. And smooth displacement is possible. In addition, it is possible to arbitrarily set the displacement speeds of the elasticity regulating members 58a and 58b according to the setting of the gas pressure. Further, since the compressed gas is discharged from the enclosing chamber 54 through the throttle passage constituted by the bypass passage 55, the compressed gas is transferred at the time of transition from the action preventing state of the elasticity to the operation member 1 to the action state. It is possible to suppress the rapid expansion of the resin and prevent the impact from acting.
[0021]
8 and 9 show a first modification of the present invention, which is provided with an elasticity applying mechanism 130 and an elasticity control mechanism 150 which are different from those of the above embodiment.
The elasticity applying mechanism 130 includes a second rotating shaft 70 supported by the vehicle body, a pair of helical springs 71a and 71b fitted to the second rotating shaft 70, and the rotating shaft 10 and the second rotating shaft 70. A gear mechanism 72 for transmitting rotation is provided. One end of each spring 71a, 71b is pressed against receiving portions 72a, 72b provided on the vehicle body side. When the other end side of each spring 71a, 71b is not blocked by the elasticity control mechanism 150 from the action of the elasticity to the operation member 1, as shown by the broken line in FIG. 70a is touched. Accordingly, when the second rotary shaft 70 rotates in one direction due to the rotation of the operation member 1 by steering to the left or right, one spring 71a is elastically deformed by being pressed against the pressing portion 70a, and the operation member 1 is steered straight. Generate elasticity to return to position. Further, when the second rotating shaft 70 rotates in the other direction due to the rotation of the operating member 1 by steering to the left and right other side, the other spring 71b is elastically deformed by being pressed against the pressing portion 70a, thereby moving the operating member 1 to the straight steering position. Generates elasticity to return to.
The elastic force control mechanism 150 includes a gas cylinder (not shown) attached to the vehicle body similar to the gas cylinder 50a of the above embodiment, and an electromagnetic open / close valve connected to a control device similar to the electromagnetic open / close valve 59 of the above embodiment. And an encapsulating release mechanism. The piston rod 56 of the gas cylinder is connected to the other ends of the springs 71a and 71b via elastic restriction members 158a and 158b formed of flexible cords such as wires, and the elastic restriction members 158a and 158b are connected to the vehicle body side. Are hooked on pulleys 74a and 74b attached to the belt.
Until the abnormality of the operating actuator 19 is detected, the piston rod 56 is in a contracted state, and the elastic force restricting members 158a and 158b are positioned at the position where the elastic force acting on the operating member 1 is prevented as shown by the one-dot chain line in FIG. The other ends of the springs 71a and 71b are arranged at positions where they do not come into contact with the pressing portion 70a as indicated by solid lines. When the control device 20 detects an abnormality of the operating actuator 19, the piston rod 56 is extended by sending an open signal to the electromagnetic opening / closing valve, and the elasticity regulating member 158a cancels the inhibition of the action of elasticity on the operating member 1 indicated by a broken line in the figure. The other ends of the springs 71a and 71b are in contact with the pressing portion 70a. Others are the same as the above embodiment, and the same parts are denoted by the same reference numerals.
[0022]
FIG. 10 shows a second modification of the present invention, which includes the elasticity applying mechanism 130 similar to the first modification, and an elasticity control mechanism 250 different from the above embodiment and the first modification.
The elasticity control mechanism 250 includes a pair of gas cylinders 250 a attached to the vehicle body side and a sealing release mechanism configured by a pair of electromagnetic on-off valves 260 connected to the control device 20. Both springs 71a and 71b are arranged between both gas cylinders 250a. Each gas cylinder 250 a is provided with a sealing chamber 253 surrounded by the inner surface of the cylinder tube 251 and the pressure receiving surface of the piston 252, and an elasticity regulating member 258 is attached to the tip of a piston rod 256 integrated with the piston 252. . The enclosing chamber 253 communicates with the atmosphere opening 255 via the electromagnetic opening / closing valve 260.
Until the abnormality of the operating actuator 19 is detected, the high-pressure gas held in the compressed state is sealed in the sealing chamber 253, and each piston rod 256 is extended. In this state, the both elastic force restricting members 258 are positioned at the position where the elastic force is not applied to the operating member 1, and contact the pulley 259 attached to the other ends of the two springs 71a and 71b as shown by solid lines in the figure. Thus, the other ends of the springs 71a and 71b are arranged at positions where they do not contact the pressing portion 70a. When the controller 20 sends an open signal to the electromagnetic opening / closing valve 260 when an abnormality of the operation actuator 19 is detected, the gas sealed in the sealing chamber 253 is discharged into the atmosphere, thereby expanding, and the springs 71a and 71b. As a result, the piston rods 256 are contracted by the elastic force, the elastic force restricting member 258 is displaced to the position where the elastic member is prevented from acting, and the other ends of the springs 71a and 71b are indicated by broken lines in FIG. By contacting the pressing portion 70a, elasticity is generated that returns the operating member 1 to the straight steering position. Others are the same as those in the above embodiment and the first modification, and the same parts are denoted by the same reference numerals.
[0023]
FIG. 11 shows a third modification of the present invention, which includes the elasticity applying mechanism 130 similar to the first modification, and the elasticity control mechanism 350 different from the above-described embodiment and the first and second modifications. The elasticity control mechanism 350 includes a pair of gas cylinders 50a mounted on the vehicle body side similar to the above-described embodiment and a pair of gas cylinders 50a similar to the above-described embodiment that opens and closes bypass passages that connect both the enclosed chambers of each gas cylinder 50a. An electromagnetic opening / closing valve 59 is provided, and both gas cylinders 50a are disposed between the other ends of both springs 71a, 71b. The tip of the piston rod 56 of each gas cylinder 50a is bent into a hook shape, and the same elasticity regulating member 258 as that of the second modification is attached to the tip.
Until the abnormality of the operating actuator 19 is detected, both piston rods 56 are in the contracted state. In this state, the both elastic force restricting members 258 are positioned at the position where the elastic force is not applied to the operating member 1, and contact the pulley 259 attached to the other ends of the two springs 71a and 71b as shown by solid lines in the figure. Thus, the other ends of the springs 71a and 71b are arranged at positions where they do not contact the pressing portion 70a. When the control device 20 detects an abnormality of the operation actuator 19, each piston rod 56 is extended by sending an open signal to each electromagnetic open / close valve 59, whereby the elastic force restricting member 258 cancels the blocking of the action of the elastic force on the operating member 1. The other ends of the springs 71a and 71b are brought into contact with the pressing portion 70a as shown by broken lines in FIG. 11 to generate elasticity that returns the operating member 1 to the straight steering position. Others are the same as those in the above embodiment and the first and second modifications, and the same parts are denoted by the same reference numerals.
[0024]
In the above-described embodiment and modification, gas is sealed as a fluid in the sealing chamber, but instead of this, a liquid may be sealed, and the fluid sealed in the sealing chamber may not be compressed. For example, as a fourth modification, each of the sealing chambers 53 and 54 in the above embodiment may be sealed without compressing oil instead of gas, and the others may be configured in the same manner as in the above embodiment.
[0025]
The present invention is not limited to the above embodiments and modifications. For example, the elasticity for returning the operation member to the straight steering position may be generated by a different type of spring, rubber, or the like.
[0026]
【The invention's effect】
According to the present invention, in a steering apparatus for a vehicle that employs a steer-by-wire system, an operation actuator can be manufactured without a feeling of deterioration, with a compact structure, without consuming a large amount of energy, and without giving an impact. When an abnormality occurs, a fail-safe function can be achieved by applying an elastic force that returns the operating member to the straight-ahead steering position.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the configuration of a vehicle steering system according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an elasticity applying mechanism in a straight-ahead steering state when an abnormality of an operation actuator is detected in the vehicle steering apparatus according to the embodiment of the present invention.
FIG. 3 is a cross-sectional view of an elasticity applying mechanism in a left steering state when an abnormality is detected in an operation actuator in a vehicle steering apparatus according to an embodiment of the present invention.
FIG. 4 is a cross-sectional view of an elastic force applying mechanism in a right steering state when an abnormality of an operation actuator is detected in a vehicle steering apparatus according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating the configuration of an elasticity control mechanism in the vehicle steering apparatus according to the embodiment of the present invention.
FIG. 6 is a configuration explanatory diagram of a main part of the elasticity control mechanism in the vehicle steering system according to the embodiment of the present invention.
FIG. 7 is a flowchart showing a control procedure of the operation actuator and the steering actuator in the vehicle steering apparatus according to the embodiment of the present invention.
FIG. 8 is an explanatory view of the arrangement of the elasticity applying mechanism in the vehicle steering system according to the first modified example of the present invention.
FIG. 9 is a diagram illustrating the configuration of the elasticity applying mechanism and the elasticity control mechanism in the vehicle steering system according to the first modification of the present invention.
FIG. 10 is a diagram illustrating the configuration of an elasticity applying mechanism and an elasticity control mechanism in a vehicle steering apparatus according to a second modification of the present invention.
FIG. 11 is a diagram illustrating the configuration of an elasticity applying mechanism and an elasticity control mechanism in a vehicle steering apparatus according to a third modification of the present invention.
[Explanation of symbols]
1 Operation member
2 Steering actuator
3 Steering gear mechanism
4 wheels
19 Actuator for operation
20 Control device
30, 130 Elasticity imparting mechanism
50, 150, 250, 350 Elasticity control mechanism
50a Gas cylinder (encapsulation release mechanism)
53, 54 Enclosure chamber
55 Bypass passage (throttle passage)
58a First elasticity regulating member
58b Second elasticity regulating member
59 Electromagnetic on-off valve (encapsulation release mechanism)
158a, 258 Elasticity restricting member

Claims

An operation member;
An operating actuator for generating a force acting on the operating member;
A steering actuator;
A mechanism for transmitting the movement of the steering actuator to the wheel so that a steering angle change occurs without mechanically connecting the operation member to the wheel;
A control device for controlling the operating actuator and the steering actuator in accordance with an operation of the operating member;
An abnormality detection means of the operating actuator;
Means for releasing the action of the generated force of the operating actuator on the operating member when the abnormality is detected;
A resilience providing mechanism for generating resilience for returning the operation member to the straight steering position;
A vehicle steering apparatus comprising: an elastic force control mechanism that blocks the operation of the elastic force on the operation member until the abnormality is detected and releases the blocking when the abnormality is detected.

The elasticity control mechanism includes a sealing chamber that encloses a fluid, a sealing release mechanism that holds the fluid in a sealed state until the abnormality is detected and releases the sealing when the abnormality is detected, and a change in fluid volume in the sealing chamber. An elastic restriction member that displaces
The elastic force restricting member is positioned at a position where the elastic member is prevented from acting on the operating member in the fluid sealed state, and the elastic member is released from the sealed state to prevent the elastic member from acting on the operating member. The vehicle steering apparatus according to claim 1, wherein the vehicle steering apparatus is displaced from a position to a blocking release position.

The vehicle steering apparatus according to claim 2, wherein the fluid is sealed in the sealed chamber in a compressed state and expands when the sealed state is released.

The vehicle steering apparatus according to claim 3, wherein the fluid in the compressed state expands by being discharged from the sealing chamber through a throttle passage.