JP3829926B2 - Brake control device for vehicle - Google Patents

Brake control device for vehicle Download PDF

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JP3829926B2
JP3829926B2 JP2001360517A JP2001360517A JP3829926B2 JP 3829926 B2 JP3829926 B2 JP 3829926B2 JP 2001360517 A JP2001360517 A JP 2001360517A JP 2001360517 A JP2001360517 A JP 2001360517A JP 3829926 B2 JP3829926 B2 JP 3829926B2
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braking force
vehicle
braking
pressure
amount
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JP2003160040A (en
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恭司 水谷
千章 濱田
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Toyota Motor Corp
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Toyota Motor Corp
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Description

【０００１】
【発明の属する技術分野】
本発明は、自動車等の車輌の制動制御装置に係り、更に詳細には前後輪の制動力配分制御を行う車輌の制動制御装置に係る。
【０００２】
【従来の技術】
自動車等の車輌の制動制御装置の一つとして、例えば本願出願人の出願にかかる特開平１０−３３８１１５号公報に記載されている如く、車輌の制動時に後輪がロックすることを防止して車輌の走行安定性を向上させるべく、車輌の運転状態が所定の状態になると後輪の制動圧を保持又は減圧し或いはパルス増圧して後輪の制動力の上昇を抑制する前後輪制動力配分制御を行うよう構成された制動制御装置が従来より知られている。
【０００３】
この種の制動制御装置によれば、前後輪制動力配分制御が行われない場合に比して、後輪が前輪よりも先行してロック状態になること及びこれに起因して車輌の安定性が悪化する虞れを低減することができるので、車輌の走行安定性を向上させることができる。
【０００４】
【発明が解決しようとする課題】
しかし上記公開公報に記載されている如き前後輪制動力配分制御を行う制動制御装置に於いては、前後輪制動力配分制御が実行されると後輪の制動力の上昇が抑制されるため、運転者が制動力を高くしようとして制動操作量を増大させても車輌全体としての制動力が十分に上昇せず、そのため制動操作フィーリングが悪いという問題がある。
【０００５】
本発明は、車輌の運転状態が所定の状態になると後輪の制動力の上昇を抑制する前後輪制動力配分制御を行うよう構成された従来の制動制御装置に於ける上述の問題に鑑みてなされたものであり、本発明の主要な課題は、前後輪制動力配分制御が行われる制動操作領域よりも低い制動操作領域に於いて前輪の制動力を後輪の制動力よりも相対的に高くすることにより、後輪が前輪よりも先行してロック状態になること及びこれに起因して車輌の安定性が悪化することを防止しつつ前後輪制動力配分制御に起因して制動操作フィーリングが悪化する虞れを低減することである。
【０００６】
【課題を解決するための手段】
上述の主要な課題は、本発明によれば、請求項１の構成、即ちマスタシリンダの作動液圧を各車輪に対応して設けられた制動力発生装置のホイールシリンダへ供給することにより制動力を発生し、車輌の運転状態が所定の状態になると後輪の制動力の上昇を抑制する前後輪制動力配分制御を行う車輌の制動制御装置にして、運転者の制動操作量について見て前記前後輪制動力配分制御が行われる領域以下の領域に於いて前輪の制動力を運転者の制動操作量に対応する制動力よりも高くする前輪制動力付加手段を有し、前記前輪制動力付加手段は運転者の制動操作量が基準値以上であるときに前輪の制動力を運転者の制動操作量に対応する制動力よりも高くし、前記基準値を車輌の状態に応じて変更することを特徴とする車輌の制動制御装置によって達成される。
【０００９】
また本発明によれば、上述の主要な課題を効果的に達成すべく、上記請求項１の構成に於いて、前記前輪制動力付加手段は前輪の制動力を高くする量を車輌の状態に応じて変更するよう構成される（請求項２の構成）。
また本発明によれば、上述の主要な課題を効果的に達成すべく、上記請求項２の構成に於いて、前記前輪制動力付加手段は車速が高いほど前輪の制動力を高くする量が大きくなるよう車速に応じて前輪の制動力を高くする量を可変設定するよう構成される（請求項３の構成）。
また本発明によれば、上述の主要な課題を効果的に達成すべく、上記請求項２又は３の構成に於いて、前記前輪制動力付加手段は車輌の減速度が低いほど前輪の制動力を高くする量が大きくなるよう車輌の減速度に応じて前輪の制動力を高くする量を可変設定するよう構成される（請求項４の構成）。
また本発明によれば、上述の主要な課題を効果的に達成すべく、上記請求項２乃至４の何れかの構成に於いて、前記前輪制動力付加手段は車輌の横加速度の大きさが大きいほど前輪の制動力を高くする量が大きくなるよう車輌の横加速度に応じて前輪の制動力を高くする量を可変設定するよう構成される（請求項５の構成）。
【００１０】
また本発明によれば、上述の主要な課題を効果的に達成すべく、上記請求項１乃至５の何れかの構成に於いて、前記前輪制動力付加手段は運転者の制動操作量が高くなるにつれて前輪の制動力を高くする量を大きくするよう構成される（請求項６の構成）。
また本発明によれば、上述の主要な課題を効果的に達成すべく、上記請求項１乃至６の何れかの構成に於いて、前記前輪制動力付加手段は車速が高いほど前記基準値が小さくなるよう車速に応じて前記基準値を可変設定するよう構成される（請求項７の構成）。
また本発明によれば、上述の主要な課題を効果的に達成すべく、上記請求項１乃至７の何れかの構成に於いて、前記前輪制動力付加手段は車輌の減速度が低いほど前記基準値が大きくなるよう車輌の減速度に応じて前記基準値を可変設定する量を可変設定するよう構成される（請求項８の構成）。
また本発明によれば、上述の主要な課題を効果的に達成すべく、上記請求項１乃至８の何れかの構成に於いて、前記前輪制動力付加手段は車輌の横加速度の大きさが大きいほど前記基準値が小さくなるよう車輌の横加速度に応じて前記基準値を可変設定するよう構成される（請求項９の構成）。
【００１１】
【発明の作用及び効果】
上記請求項１の構成によれば、運転者の制動操作量について見て前後輪制動力配分制御が行われる領域以下の領域に於いて前輪の制動力が付加され運転者の制動操作量に対応する制動力よりも高くされ、これにより前後輪制動力配分制御に先立って制動力の前後輪配分が予め前輪寄りに制御されるので、前輪の制動力が高くされない場合に比して、運転者の制動操作量が比較的高い領域に於いても後輪が前輪よりも先行してロック状態になること及びこれに起因して車輌の安定性が悪化する虞れを低減することができ、また前輪の制動力が高くされない場合に比して、前後輪制動力配分制御が行われるべき領域を運転者の制動操作量が高い領域にすることができ、従って前後輪制動力配分制御が行われない制動操作領域を広くし、これにより前後輪制動力配分制御に起因して制動操作フィーリングが悪化する虞れを低減することができる。
また上記請求項１の構成によれば、運転者の制動操作量が基準値以上であるときに前輪の制動力が運転者の制動操作量に対応する制動力よりも高くされるので、運転者の制動操作量が基準値以上である状況に於いて確実に前輪の制動力を運転者の制動操作量に対応する制動力よりも高くすることができると共に、前輪の制動力の付加が必要ではない状況に於いて前輪の制動力が不必要に運転者の制動操作量に対応する制動力よりも高くされることを確実に防止することができる。
更に上記請求項１の構成によれば、基準値は車輌の状態に応じて変更されるので、運転者の制動操作量が増大する際に於ける前輪の制動力の付加の開始を車輌の状態に応じて的確に制御することができる。
【００１４】
また上記請求項２の構成によれば、前輪の制動力を高くする量が車輌の状態に応じて変更されるので、前輪の制動力の付加量を車輌の状態に応じて的確に制御することができ、これにより車輌の状態に応じた適正な付加量にて前輪の制動力を高くすることができる。
また上記請求項３の構成によれば、車速が高いほど前輪の制動力を高くする量が大きくなるよう車速に応じて前輪の制動力を高くする量が可変設定されるので、車速が高いほど前輪の制動力の付加量を大きくして車輌が不安定になることを効果的に防止することができる。
また上記請求項４の構成によれば、車輌の減速度が低いほど前輪の制動力を高くする量が大きくなるよう車輌の減速度に応じて前輪の制動力を高くする量が可変設定されるので、車輌の積載荷重が高いことに起因して車輌の減速度が低い状況に於いて車輌全体の制動力が不足することに起因して車輌の減速度が不足することを確実に防止することができる。
また上記請求項５の構成によれば、車輌の横加速度の大きさが大きいほど前輪の制動力を高くする量が大きくなるよう車輌の横加速度に応じて前輪の制動力を高くする量が可変設定されるので、車輌の横加速度の大きさが大きいほど前輪の制動力の付加量を大きくして車輌が不安定似ることを効果的に防止することができる。
【００１５】
また上記請求項６の構成によれば、運転者の制動操作量が高くなるにつれて前輪の制動力を高くする量が大きくされるので、例えば前輪の制動力の付加量が一定である場合に比して前輪の制動力の付加が開始される際の制動力の急変を確実に防止することができ、また運転者の制動操作量が高くなるにつれて、即ち後輪が前輪よりも先行してロック状態になる虞れが高くなるにつれて制動力の前後配分を漸次前輪寄りに制御することができる。
また上記請求項７の構成によれば、車速が高いほど基準値が小さくなるよう車速に応じて基準値が可変設定されるので、車速が高いほど前輪の制動力の付加を早く開始して車輌が不安定になることを早期に防止することができる。
また上記請求項８の構成によれば、車輌の減速度が低いほど基準値が大きくなるよう車輌の減速度に応じて基準値が可変設定されるので、車輌の積載荷重が高く車輌の減速度が低い状況に於いて前輪の制動力が早期に過剰に増大することを確実に防止することができる。
また上記請求項９の構成によれば、車輌の横加速度の大きさが大きいほど基準値が小さくなるよう車輌の横加速度に応じて基準値が可変設定されるので、車輌の横加速度の大きさが大きいほど輪の制動力の付加を早く開始して車輌が不安定になることを早期に防止することができる。
【００１６】
【課題解決手段の好ましい態様】
本発明の一つの好ましい態様によれば、上記請求項１の構成に於いて、前輪制動力付加手段は前後輪制動力配分制御が行われる領域よりも運転者の制動操作量が小さい領域及び前後輪制動力配分制御が行われる領域に於いて前輪の制動力を運転者の制動操作量に対応する制動力よりも高くするよう構成される（好ましい態様１）。
【００２１】
本発明の他の一つの好ましい態様によれば、上記請求項１乃至９の何れかの構成に於いて、前後輪制動力配分制御が行われているときには後輪の制動力の上昇抑制量に応じて前輪の制動力が増加されるよう構成される（好ましい態様２）。
【００２２】
【発明の実施の形態】
以下に添付の図面を参照して本発明を幾つかの好ましい実施形態について詳細に説明する。
【００２３】
第一の実施形態
図１は本発明による制動制御装置の第一の実施形態の油圧回路及び電子制御装置を示す概略構成図、図２は図１に示された前輪用の連通制御弁を示す解図的断面図である。尚図１に於いては、電磁的に駆動される各弁のソレノイドの図示は省略されている。
【００２４】
図１に於て、１０は油圧式の制動装置を示しており、制動装置１０は運転者によるブレーキペダル１２の踏み込み操作に応答してブレーキオイルを圧送するマスタシリンダ１４を有している。マスタシリンダ１４はその両側の圧縮コイルばねにより所定の位置に付勢されたフリーピストン１６により画成された第一のマスタシリンダ室１４Ａと第二のマスタシリンダ室１４Ｂとを有している。
【００２５】
第一のマスタシリンダ室１４Ａには前輪用のブレーキ油圧制御導管１８Ｆの一端が接続され、ブレーキ油圧制御導管１８Ｆの他端には左前輪用のブレーキ油圧制御導管２０FL及び右前輪用のブレーキ油圧制御導管２０FRの一端が接続されている。ブレーキ油圧制御導管１８Ｆの途中には前輪用の連通制御弁２２Ｆが設けられており、連通制御弁２２Ｆは図示の実施形態に於いては常開型のリニアソレノイド弁である。連通制御弁２２Ｆの両側のブレーキ油圧制御導管１８Ｆには第一のマスタシリンダ室１４Ａよりブレーキ油圧制御導管２０FL又はブレーキ油圧制御導管２０FRへ向かうオイルの流れのみを許す逆止バイパス導管２４Ｆが接続されている。
【００２６】
図２に解図的に図示されている如く、連通制御弁２２Ｆは内部に弁室７０を郭定するハウジング７２を有し、弁室７０には弁要素７４が往復動可能に配置されている。弁室７０にはブレーキ油圧制御導管１８Ｆのマスタシリンダ１４の側の部分１８ＦＡが内部通路７６を介して常時連通接続され、またブレーキ油圧制御導管１８Ｆのマスタシリンダ１４とは反対側の部分１８ＦＢが内部通路７８及びポート８０を介して連通接続されている。
【００２７】
図示の如く、弁要素７４の周りにはソレノイド８２が配設されており、弁要素７４は圧縮コイルばね８４により図２に示された開弁位置へ付勢されている。弁要素７４はソレノイド８２に駆動電圧が印加されると、圧縮コイルばね８４のばね力に抗してポート８０に対し付勢され、これによりポート８０を閉ざすことによって閉弁する。
【００２８】
また連通制御弁２２Ｆが閉弁位置にある状況に於いて、ブレーキ油圧制御導管１８Ｆのマスタシリンダ１４とは反対側の部分１８ＦＢ内の圧力による力と圧縮コイルばね８４のばね力との合計がソレノイド８２による電磁力よりも高くなると、弁要素７４はポート８０より離れて該ポートを開き、部分１８ＦＢ内のオイルが内部通路７８、ポート８０、弁室７０、内部通路７６を経てブレーキ油圧制御導管１８Ｆの部分１８ＦＡへ流れる。そしてこのオイルの流動により部分１８ＦＢ内のオイルの圧力が低下すると、その圧力による力と圧縮コイルばね８４のばね力との合計がソレノイド８２による電磁力よりも低くなり、弁要素７４はポート８０を再度閉ざす。
【００２９】
かくして連通制御弁２２Ｆはそのソレノイド８２に対する印加電圧に応じてブレーキ油圧制御導管１８Ｆの部分１８ＦＢ内の圧力を制御するので、ソレノイド８２に対する駆動電圧を制御することによって連通制御弁２２Ｆにより部分１８ＦＢ内の圧力（本明細書に於いては「上流圧」という）を所望の圧力に制御することができる。
【００３０】
尚図示の実施形態に於いては、図１に示された逆止バイパス導管２４Ｆは連通制御弁２２Ｆに内蔵されており、内部通路８６と、該内部通路の途中に設けられ弁室７０より部分１８ＦＢへ向かうオイルの流れのみを許す逆止弁８８とよりなっている。
【００３１】
左前輪用のブレーキ油圧制御導管２０FL及び右前輪用のブレーキ油圧制御導管２０FRの他端にはそれぞれ左前輪及び右前輪の制動力を発生する図１には示されていない制動力発生装置のホイールシリンダ２６FL及び２６FRが接続されており、左前輪用のブレーキ油圧制御導管２０FL及び右前輪用のブレーキ油圧制御導管２０FRの途中にはそれぞれ常開型の電磁開閉弁２８FL及び２８FRが設けられている。電磁開閉弁２８FL及び２８FRの両側のブレーキ油圧制御導管２０FL及び２０FRにはそれぞれホイールシリンダ２６FL及び２６FRよりブレーキ油圧制御導管１８Ｆへ向かうオイルの流れのみを許す逆止バイパス導管３０FL及び３０FRが接続されている。
【００３２】
電磁開閉弁２８FLとホイールシリンダ２６FLとの間のブレーキ油圧制御導管２０FLにはオイル排出導管３２FLの一端が接続され、電磁開閉弁２８FRとホイールシリンダ２６FRとの間のブレーキ油圧制御導管２０FRにはオイル排出導管３２FRの一端が接続されている。オイル排出導管３２FL及び３２FRの途中にはそれぞれ常閉型の電磁開閉弁３４FL及び３４FRが設けられており、オイル排出導管３２FL及び３２FRの他端は接続導管３６Ｆにより前輪用のバッファリザーバ３８Ｆに接続されている。
【００３３】
以上の説明より解る如く、電磁開閉弁２８FL及び２８FRはそれぞれホイールシリンダ２６FL及び２６FR内の圧力を増圧又は保持するための増圧弁であり、電磁開閉弁３４FL及び３４FRはそれぞれホイールシリンダ２６FL及び２６FR内の圧力を減圧するための減圧弁であり、従って電磁開閉弁２８FL及び３４FLは互いに共働して左前輪のホイールシリンダ２６FL内の圧力を増減し保持するための増減圧弁を郭定しており、電磁開閉弁２８FR及び３４FRは互いに共働して右前輪のホイールシリンダ２６FR内の圧力を増減し保持するための増減圧弁を郭定している。
【００３４】
接続導管３６Ｆは接続導管４０Ｆによりポンプ４２Ｆの吸入側に接続されており、接続導管４０Ｆの途中には接続導管３６Ｆよりポンプ４２Ｆへ向かうオイルの流れのみを許す二つの逆止弁４４Ｆ及び４６Ｆが設けられている。ポンプ４２Ｆの吐出側は途中にダンパ４８Ｆを有する接続導管５０Ｆによりブレーキ油圧制御導管１８Ｆに接続されている。ポンプ４２Ｆとダンパ４８Ｆとの間の接続導管５０Ｆにはポンプ４２Ｆよりダンパ４８Ｆへ向かうオイルの流れのみを許す逆止弁５２Ｆが設けられている。
【００３５】
二つの逆止弁４４Ｆ及び４６Ｆの間の接続導管４０Ｆには接続導管５４Ｆの一端が接続されており、接続導管５４Ｆの他端は第一のマスタシリンダ室１４Ａと制御弁２２Ｆとの間のブレーキ油圧制御導管１８Ｆに接続されている。接続導管５４Ｆの途中には常閉型の電磁開閉弁６０Ｆが設けられている。この電磁開閉弁６０Ｆはマスタシリンダ１４と制御弁２２Ｆとの間のブレーキ油圧制御導管１８Ｆとポンプ４２Ｆの吸入側との連通を制御する吸入制御弁として機能する。
【００３６】
同様に、第二のマスタシリンダ室１４Ｂには後輪用のブレーキ油圧制御導管１８Ｒの一端が接続され、ブレーキ油圧制御導管１８Ｒの他端には左後輪用のブレーキ油圧制御導管２０RL及び右後輪用のブレーキ油圧制御導管２０RRの一端が接続されている。ブレーキ油圧制御導管１８Ｒの途中には常開型のリニアソレノイド弁である後輪用の連通制御弁２２Ｒが設けられている。
【００３７】
連通制御弁２２Ｒは前輪用の連通制御弁２２Ｆについて図２に示された構造と同一の構造を有しており、従って図には示されていないソレノイドに対する駆動電圧を制御することにより、連通制御弁２２Ｒより下流側のブレーキ油圧制御導管１８Ｒ内の圧力（上流圧）を所望の圧力に制御することができる。更に連通制御弁２２Ｒの両側のブレーキ油圧制御導管１８Ｒには第二のマスタシリンダ室１４Ｂよりブレーキ油圧制御導管２０RL又はブレーキ油圧制御導管２０RRへ向かうオイルの流れのみを許す逆止バイパス導管２４Ｒが接続されている。
【００３８】
左後輪用のブレーキ油圧制御導管２０RL及び右後輪用のブレーキ油圧制御導管２０RRの他端にはそれぞれ左後輪及び右後輪の制動力を発生する図１には示されていない制動力発生装置のホイールシリンダ２６RL及び２６RRが接続されており、左後輪用のブレーキ油圧制御導管２０RL及び右後輪用のブレーキ油圧制御導管２０RRの途中にはそれぞれ常開型の電磁開閉弁２８RL及び２８RRが設けられている。電磁開閉弁２８RL及び２８RRの両側のブレーキ油圧制御導管２０RL及び２０RRにはそれぞれホイールシリンダ２６RL及び２６RRよりブレーキ油圧制御導管１８Ｒへ向かうオイルの流れのみを許す逆止バイパス導管３０RL及び３０RRが接続されている。
【００３９】
電磁開閉弁２８RLとホイールシリンダ２６RLとの間のブレーキ油圧制御導管２０RLにはオイル排出導管３２RLの一端が接続され、電磁開閉弁２８RRとホイールシリンダ２６RRとの間のブレーキ油圧制御導管２０RRにはオイル排出導管３２RRの一端が接続されている。オイル排出導管３２RL及び３２RRの途中にはそれぞれ常閉型の電磁開閉弁３４RL及び３４RRが設けられており、オイル排出導管３２RL及び３２RRの他端は接続導管３６Ｒにより後輪用のバッファリザーバ３８Ｒに接続されている。
【００４０】
前輪側の場合と同様、電磁開閉弁２８RL及び２８RRはそれぞれホイールシリンダ２６RL及び２６RR内の圧力を増圧又は保持するための増圧弁であり、電磁開閉弁３４RL及び３４RRはそれぞれホイールシリンダ２６RL及び２６RR内の圧力を減圧するための減圧弁であり、従って電磁開閉弁２８RL及び３４RLは互いに共働して左後輪のホイールシリンダ２６RL内の圧力を増減し保持するための増減圧弁を郭定しており、電磁開閉弁２８RR及び３４RRは互いに共働して右後輪のホイールシリンダ２６RR内の圧力を増減し保持するための増減圧弁を郭定している。
【００４１】
接続導管３６Ｒは接続導管４０Ｒによりポンプ４２Ｒの吸入側に接続されており、接続導管４０Ｒの途中には接続導管３６Ｒよりポンプ４２Ｒへ向かうオイルの流れのみを許す二つの逆止弁４４Ｒ及び４６Ｒが設けられている。ポンプ４２Ｒの吐出側は途中にダンパ４８Ｒを有する接続導管５０Ｒによりブレーキ油圧制御導管１８Ｒに接続されている。ポンプ４２Ｒとダンパ４８Ｒとの間の接続導管５０Ｒにはポンプ４２Ｒよりダンパ４８Ｒへ向かうオイルの流れのみを許す逆止弁５２Ｒが設けられている。尚ポンプ４２Ｆ及び４２Ｒは図１には示されていない共通の電動機により駆動される。
【００４２】
二つの逆止弁４４Ｒ及び４６Ｒの間の接続導管４０Ｒには接続導管５４Ｒの一端が接続されており、接続導管５４Ｒの他端は第二のマスタシリンダ室１４Ｂと制御弁２２Ｒとの間のブレーキ油圧制御導管１８Ｒに接続されている。接続導管５４Ｒの途中には常閉型の電磁開閉弁６０Ｒが設けられている。この電磁開閉弁６０Ｒもマスタシリンダ１４と制御弁２２Ｒとの間のブレーキ油圧制御導管１８Ｒとポンプ４２Ｒの吸入側との連通を制御する吸入制御弁として機能する。
【００４３】
図示の実施形態に於いては、各制御弁及び各開閉弁は対応するソレノイドに駆動電流が通電されていないときには図１に示された非制御位置に設定され、これによりホイールシリンダ２６FL及び２６FRには第一のマスタシリンダ室１４Ａ内の圧力が供給され、ホイールシリンダ２６RL及び２６RRには第二のマスタシリンダ室１４Ｂ内の圧力が供給される。従って通常時には各車輪のホイールシリンダ内の圧力、即ち制動力はブレーキペダル１２の踏力に応じて増減される。
【００４４】
これに対し連通制御弁２２Ｆ、２２Ｒが閉弁位置に切り換えられ、開閉弁６０Ｆ、６０Ｒが開弁され、各車輪の開閉弁が図１に示された位置にある状態にてポンプ４２Ｆ、４２Ｒが駆動されると、マスタシリンダ１４内のオイルがポンプによって汲み上げられ、ホイールシリンダ２６FL、２６FRにはポンプ４２Ｆによりポンプアップされた圧力が供給され、ホイールシリンダ２６RL、２６RRにはポンプ４２Ｒによりポンプアップされた圧力が供給されるようになるので、各車輪の制動圧はブレーキペダル１２の踏力に関係なく連通制御弁２２Ｆ、２２Ｒ及び各車輪の開閉弁（増減圧弁）の開閉により増減される。
【００４５】
この場合、ホイールシリンダ内の圧力は、開閉弁２８FL〜２８RR及び開閉弁３４FL〜３４RRが図１に示された非制御位置にあるときには増圧され（増圧モード）、開閉弁２８FL〜２８RRが閉弁位置に切り換えられ且つ開閉弁３４FL〜３４RRが図１に示された非制御位置にあるときには保持され（保持モード）、開閉弁２８FL〜２８RR及び開閉弁３４FL〜３４RRが開弁位置に切り換えられると減圧される（減圧モード）。
【００４６】
連通制御弁２２Ｆ及び２２Ｒ、開閉弁２８FL〜２８RR、開閉弁３４FL〜３４RR、開閉弁６０Ｆ及び６０Ｒは、後に説明する如く電子制御装置９０により制御される。電子制御装置９０はマイクロコンピュータ９２と駆動回路９４とよりなっており、マイクロコンピュータ９２は当技術分野に於いて周知の一般的な構成のものであってよい。
【００４７】
マイクロコンピュータ９２には圧力センサ９６よりマスタシリンダ圧力Ｐmを示す信号、車速センサ９８より車速Ｖを示す信号、前後加速度センサ１００より車輌の前後加速度Ｇx、横加速度センサ１０２より車輌の横加速度Ｇyを示す信号が入力されるようになっている。またマイクロコンピュータ９２は後述の制動制御フローを記憶しており、制動制御フローに従って各車輪の制動圧Ｐi（ｉ＝fl、fr、rl、rr）を制御する。
【００４８】
特に図示の実施形態に於いては、運転者による制動操作量が小さく制動力の前後配分制御が不要であるときには、連通制御弁２２Ｆ等は図示の標準位置に維持されポンプ４２Ｆ及び４２Ｒは駆動されず、これにより各車輪の制動圧、即ちホイールシリンダ２６FL〜２６RR内の圧力はマスタシリンダ圧力Ｐmにより制御される。
【００４９】
これに対し運転者による制動操作量が大きく制動力の前後配分制御により後輪の制動力の上昇を抑制する必要があるときには、左右後輪の開閉弁２８RL及び２８RRが閉弁されることにより左右後輪の制動圧が一定の値に保持され、これと同時に連通制御弁２２Ｆが閉弁され、吸入制御弁６０Ｆが開弁され、ポンプ４２Ｆが駆動され、連通制御弁２２Ｆが制御されることにより左右前輪の制動圧が増加され、これにより後輪の制動圧が一定の値に保持されることによる制動力の不足分が前輪の制動力の増大により補足される。
【００５０】
更に図示の実施形態に於いては、制動力の前後配分制御が実行される制動操作領域よりも低い制動操作領域に於いて連通制御弁２２Ｆが閉弁され、吸入制御弁６０Ｆが開弁され、ポンプ４２Ｆが駆動され、連通制御弁２２Ｆが制御されることにより、後に詳細に説明する如く左右前輪の制動圧がマスタシリンダ圧力Ｐmよりも高い値に増圧され、これにより制動力の前後配分制御の実行に先立って制動力の前後輪配分が予め前輪寄りに制御される。
【００５１】
尚図には示されていないが、電磁開閉弁２８FL〜２８RR及び開閉弁３４FL〜３４RRは例えば各車輪の制動力を個別に制御することにより車輌の挙動を安定化させる場合に制御される。特にこの場合左右の車輪の高い方の目標制動圧が目標上流圧Ｐtf、Ｐtrに設定され、左右の車輪の目標制動圧Ｐtiが高い方の車輪の制動圧Ｐiは連通制御弁２２Ｆ又は２２Ｒにより上流圧が目標上流圧Ｐtf又はＰtrに制御されることによって制御され、左右反対側の車輪の制動圧は対応する増圧弁及び減圧弁により対応する目標制動圧に制御される。
【００５２】
次に図３に示されたフローチャートを参照して図示の第一の実施形態に於ける制動制御ルーチンについて説明する。尚図３に示されたフローチャートによる制御は図には示されていないイグニッションスイッチの閉成により開始され、所定の時間毎に繰り返し実行される。
【００５３】
まずステップ１０に於いては圧力センサ９６により検出されたマスタシリンダ圧力Ｐmを示す信号等の読み込みが行われ、ステップ２０に於いては車速Ｖ、車輌の減速度Ｇxb（＝−Ｇx）、車輌の横加速度Ｇyを変数とする関数Ｆp（Ｖ，Ｇxb，Ｇy）により下記の式１に従って基準値Ｐmoが演算される。尚この場合、基準値Ｐmoは後述の後輪の制動力の抑制による前後輪制動力配分制御が行われる領域のマスタシリンダ圧力Ｐmよりも小さい正の値であり、車速Ｖが高いほど小さく、車輌の減速度Ｇxbが小さいほど大きく、車輌の横加速度Ｇyの大きさが大きいほど小さくなるよう演算される。
Ｐmo＝Ｆp（Ｖ，Ｇxb，Ｇy） ……（１）
【００５４】
ステップ３０に於いてはマスタシリンダ圧力Ｐmが基準値Ｐmo以上であるか否かの判別、即ち前輪の制動力を付加して制動力の前後輪配分比を予め前輪寄りに制御するが必要があるか否かの判別が行われ、否定判別が行われたときにはそのまま図３に示されたルーチンによる制御を一旦終了し、肯定判別が行われたときにはステップ４０へ進む。
【００５５】
ステップ４０に於いてはマスタシリンダ圧力Ｐm、車速Ｖ、車輌の減速度Ｇxb、車輌の横加速度Ｇyを変数とする関数Ｆf（Ｐm，Ｖ，Ｇxb，Ｇy）により下記の式２に従って前輪の目標制動圧Ｐtfが演算されると共に、マスタシリンダ圧力Ｐmを変数とする関数Ｆr（Ｐm）により下記の式３に従って後輪の目標制動圧Ｐtrが演算される。
Ｐtf＝Ｆf（Ｐm，Ｖ，Ｇxb，Ｇy） ……（２）
Ｐtr＝Ｆr（Ｐm） ……（３）
【００５６】
例えば図４に示されている如く、前輪の目標制動圧Ｐtfはマスタシリンダ圧力Ｐmが基準値Ｐmo未満の範囲に於いてはマスタシリンダ圧力Ｐmと同一の値に演算され、マスタシリンダ圧力Ｐmが基準値Ｐmo以上の範囲に於いてはマスタシリンダ圧力Ｐmに対し１よりも大きい係数Ｋが乗算された値に演算される。また後輪の目標制動圧Ｐtrはマスタシリンダ圧力Ｐmの値に拘わらずマスタシリンダ圧力Ｐmと同一の値に演算される。またこの場合、係数Ｋは車速Ｖが高いほど大きく、車輌の減速度Ｇxbが小さいほど大きく、車輌の横加速度Ｇyの大きさが大きいほど大きくなるよう、車速Ｖ、車輌の減速度Ｇxb、車輌の横加速度Ｇyに応じて可変設定される。
【００５７】
ステップ５０に於いては後輪の制動力を抑制することによる前後輪の制動力配分制御中であるか否かの判別、即ち後述のステップ６０又は７０に於いて肯定判別が行われた後であってステップ９０に於いて肯定判別が行われていない状況であるか否かの判別が行われ、肯定判別が行われたときにはステップ９０へ進み、否定判別が行われたときにはステップ６０へ進む。
【００５８】
ステップ６０に於いてはマスタシリンダ圧力Ｐmが後輪の保持圧力Ｐc（Ｐmoよりも大きい正の定数）を越えているか否かの判別、即ち後輪の制動圧を保持すると共に前輪の制動圧を補填増加する必要があるか否かの判別が行われ、肯定判別が行われたときにはステップ１１０へ進み、否定判別が行われたときにはステップ７０へ進む。
【００５９】
ステップ７０に於いては当技術分野に於いて公知の任意の要領にて前後輪の制動力配分制御の他の開始条件が成立したか否かの判別が行われ、否定判別が行われたときにはステップ１００へ進み、肯定判別が行われたときにはステップ８０に於いて後輪の保持圧力Ｐcがその時のマスタシリンダ圧力Ｐmに設定され、しかる後ステップ１１０へ進む。
【００６０】
尚前後輪の制動力配分制御の他の開始条件が成立したか否かの判別は、例えば（Ａ）左右前輪の車輪速度の平均値Ｖwfに対する左右後輪の車輪速度の平均値Ｖwrの偏差ΔＶwが制御開始基準値Ｖws（正の定数）以上になったか否かの判別、又は（Ｂ）車輌の減速度Ｇxbが制御開始基準値Ｇxs（正の定数）以上になったか否かの判別により行われてよく、また上記（Ａ）及び（Ｂ）の組合せにより行われてもよい。
【００６１】
ステップ９０に於いては例えばマスタシリンダ圧力Ｐmが制御終了の基準値Ｐme（Ｐmoよりも大きくＰcよりも小さい正の定数）以下になったか否かの判別により、前後輪の制動力配分制御の終了条件が成立したか否かの判別が行われ、肯定判別が行われたときにはステップ１００に於いて前輪の制動圧の増加圧力ΔＰfが０に設定されると共に、後輪の目標制動圧Ｐtrがマスタシリンダ圧力Ｐmに設定された後ステップ１３０へ進み、否定判別が行われたときにはステップ１１０へ進む。
【００６２】
尚前後輪の制動力配分制御の終了条件が成立したか否かの判別も当技術分野に於いて公知の任意の要領にて行われてよく、例えば制御開始条件の成立判定が車輪速度の偏差ΔＶwに基づいて行われた場合には、車輪速度の偏差ΔＶwが制御終了基準値Ｖwe（Ｖwsよりも小さい正の定数）以下になったか否かの判別により行われてよく、また制御開始条件の成立判定が車輌の減速度Ｇxbに基づいて行われた場合には車輌の減速度Ｇxbが制御終了基準値Ｇxe（Ｇxsよりも小さい正の定数）以下になったか否かの判別により行われてよい。
【００６３】
ステップ１１０に於いては後輪の目標制動圧Ｐtrと保持圧力Ｐcとの偏差Ｐtr−Ｐc及び車速Ｖを変数とする関数Ｆfa（Ｐtr−Ｐc，Ｖ）により下記の式４に従って前輪の制動圧の増加圧力ΔＰfが演算され、ステップ１２０に於いては後輪の目標制動圧Ｐtrがその保持圧力Ｐcに設定される。
ΔＰf＝Ｆfa（Ｐtr−Ｐc，Ｖ） ……（４）
【００６４】
例えば前輪及び後輪のホイールシリンダ断面積をそれぞれＳf、Ｓr（正の定数）とし、前輪及び後輪の制動有効半径をそれぞれＲf、Ｒr（正の定数）とし、前輪及び後輪のブレーキ効き係数をそれぞれＢＥＦf、ＢＥＦr（正の定数）とし、標準のブレーキ効き係数をＢＥＦoとして、車速Ｖに基づき図５に示されたグラフに対応するマップより現在の車速に対応するブレーキ効き係数ＢＥＦvが演算され、下記の式５に従って前輪の制動圧の増加圧力ΔＰfが演算される。尚ホイールシリンダ断面積Ｓf、Ｓr及び制動有効半径Ｒf、Ｒrは制動力発生装置の仕様により定まる値であり、ブレーキ効き係数ＢＥＦf、ＢＥＦrは例えば実験的に予め求められる。

Figure 0003829926
【００６５】
ステップ１３０に於いては前輪の目標増圧量ΔＰtf（前輪の最終目標制動圧Ｐttf（＝Ｐtf＋ΔＰf）とマスタシリンダ圧Ｐmとの偏差）が下記の式６に従って演算され、また後輪の目標増圧量ΔＰtr（後輪の最終目標制動圧Ｐttr（＝Ｐtr）とマスタシリンダ圧力Ｐmとの偏差）が下記の式７に従って演算される。
ΔＰtf＝Ｐtf−Ｐm＋ΔＰf ……（６）
ΔＰtr＝Ｐtr−Ｐm ……（７）
【００６６】
ステップ１４０に於いては前輪の目標増圧量ΔＰtfに対応する連通制御弁２２Ｆの目標電流が演算され、連通制御弁２２Ｆが対応する目標電流にて制御され、これにより左右前輪の制動圧が最終目標制動圧Ｐttfになるよう制動装置１０の前輪系統が制御される。また後輪の目標増圧量ΔＰtrが負の値であるときには、左右後輪の開閉弁２８RL及び２８RRが閉弁されることにより左右後輪の制動圧が保持圧力Ｐcに保持され、後輪の目標増圧量ΔＰtrが０であるときには、左右後輪の開閉弁２８RL及び２８RRが開弁され、これにより左右後輪の制動圧が最終目標制動圧Ｐttr（＝Ｐtr）になるよう制動装置１０の後輪系統が制御される。
【００６７】
尚図３には示されていないが、上述のステップ３０に於いて否定判別が行われた場合には、連通制御弁２２Ｆ等が図１に示された標準位置に設定され、これにより各車輪のホイールシリンダ２６FR〜２６RRにはマスタシリンダ１４の圧力Ｐmが直接供給され、これにより各車輪の制動圧が運転者の制動操作量に応じて増減される。
【００６８】
かくして図示の第一の実施形態によれば、運転者により制動操作量が増大され、マスタシリンダ圧力Ｐmが基準値Ｐmo以上になると、ステップ３０に於いて肯定判別が行われ、ステップ４０に於いて前輪の目標制動圧Ｐtfがマスタシリンダ圧力Ｐmよりも高い値に演算されると共に、後輪の目標制動圧Ｐtrが演算され、これにより前後輪の制動力配分制御の開始に先立って前輪の制動力が付加されることにより制動力の前後輪配分比が予め前輪寄りに制御され、前輪に先行して後輪がロックする虞れが低減される。
【００６９】
従って図６に示されている如く、前後輪の制動力配分制御の開始に先立って前輪の制動力が付加されない従来の制動制御装置の場合に比して、後輪の保持圧力を高くすることができ、前後輪の制動力配分制御が行われない制動操作範囲を広くすることができるので、後輪の制動力を有効に利用して車輌を制動することができると共に、前後輪の制動力配分制御が実行され後輪の制動力が抑制されることに起因して運転者の制動操作量に対し車輌の制動力が不足する状況になる虞れ及びこれに起因して運転者が違和感を感じる虞れを低減することができる。
【００７０】
特に図示の第一の実施形態によれば、運転者による制動操作量が更に増大され、マスタシリンダ圧力Ｐmが後輪の保持圧力Ｐcよりも高くなると、ステップ６０に於いて肯定判別が行われ、また前後輪の制動力配分制御の他の開始条件が成立すると、ステップ７０に於いて肯定判別が行われ、ステップ１１０に於いて前後輪の制動力配分制御により後輪の制動圧が保持圧力Ｐcに保持されることによる制動力の不足分を補填するための前輪の制動圧の増加圧力ΔＰfが演算され、ステップ１２０〜１４０に於いて左右前輪の制動圧が最終目標制動圧Ｐttf（＝Ｐtf＋ΔＰf）になるよう制御されると共に、左右後輪の制動圧が保持圧力Ｐcに保持され、これにより前後輪の制動力配分制御が実行される。
【００７１】
従って運転者の制動操作量が高い領域に於いて後輪の制動圧を保持圧力Ｐcに保持することにより、前輪に先行して後輪がロックすることを効果的に防止することができると共に、後輪の制動圧が保持圧力Ｐcに保持されることによる制動力の不足分が前輪の制動圧の増加によって補填されるので、前後輪の制動力配分制御が行われる比較的高い制動操作範囲に於いて後輪の制動圧が保持圧力Ｐcに保持されることに起因して運転者の制動操作量に対し車輌の制動力が不足すること及びこれに起因して運転者が違和感を感じることを効果的に防止することができる。
【００７２】
また図示の第一の実施形態によれば、マスタシリンダ圧力Ｐmが基準値Ｐmo以上になると前輪の制動力が付加されることにより、マスタシリンダ圧力Ｐmが従来の後輪保持圧力よりも高い圧力Ｐcにならなければ前後輪の制動力配分制御が開始されないので、図７に示されている如く、前後輪の制動力の関係が破線にて示された従来の場合に比して理想前後配分線に近くなり、これにより従来の場合に比して制動力の前後配分比を適正に制御することができる。
【００７３】
また図示の第一の実施形態によれば、前輪の制動圧の増加量ΔＰfは単純に後輪の制動圧の抑制量ΔＰr（＝Ｐtr−Ｐttr）に設定される訳ではなく、後輪の制動圧の抑制による後輪の制動力の不足分に対応する制動力を前輪の制動力に加算するための値として演算されるので、前輪の制動圧がマスタシリンダ圧力Ｐma＋後輪の制動圧の抑制量ΔＰrに設定される場合に比して、後輪の制動圧の抑制に起因して車輌全体の制動力が運転者の制動操作量に対し不足する虞れを確実に低減することができる。
【００７４】
また図示の第一の実施形態によれば、ステップ１１０に於いて車速Ｖが高いほどブレーキ効き係数ＢＥＦが低下することを考慮して前輪の制動圧の増加圧力ΔＰfが演算されるので、ブレーキ効き係数ＢＥＦの変動が考慮されない場合に比して前輪の制動圧の増加圧力ΔＰfを後輪の制動力の不足分に正確に対応する値に演算することができ、これにより前輪の制動圧を過不足なく適正に制御することができる。
【００７５】
第二の実施形態
図８は本発明による制動制御装置の第二の実施形態に於ける制動制御ルーチンを示すフローチャートである。尚図８に於いて、図３に示されたステップに対応するステップには図３に於いて付されたステップ番号と同一のステップ番号が付されている。
【００７６】
この第二の実施形態に於いては、ステップ１０〜９０及びステップ１２０、１４０は上述の第一の実施形態の場合と同様に実行され、上述の第一の実施形態に於けるステップ１１０に対応するステップは実行されない。またステップ７０に於いて否定判別が行われたとき及びステップ９０に於いて肯定判別が行われたときにはステップ１００へ進み、ステップ１００に於いては後輪の目標制動圧Ｐtrがマスタシリンダ圧Ｐmに設定され、ステップ１３０に於いては前輪の目標増圧量ΔＰtf（前輪の最終目標制動圧Ｐttf（＝Ｐtf）とマスタシリンダ圧Ｐmとの偏差）が下記の式８に従って演算される。
ΔＰtf＝Ｐtf−Ｐm ……（８）
【００７７】
かくして図示の第二の実施形態によれば、上述の第一の実施形態の場合と同様、運転者によって制動操作量が増大されることによりマスタシリンダ圧力Ｐmが基準値Ｐmo以上になると、図９に示されている如く、前輪の目標制動圧Ｐtfがマスタシリンダ圧力Ｐmよりも高い値に演算され、前後輪の制動力配分制御の開始に先立って前輪の制動力が付加され制動力の前後輪配分比が予め前輪寄りに制御される。
【００７８】
従って前後輪の制動力配分制御が行われない制動操作範囲を広くし後輪の制動力を有効に利用して車輌を制動することができると共に、前後輪の制動力配分制御が実行され後輪の制動力が抑制されることに起因して運転者の制動操作量に対し車輌の制動力が不足する状況になる虞れ及びこれに起因して運転者が違和感を感じる虞れを低減することができる。
【００７９】
また図示の第二の実施形態によれば、前後輪の制動力配分制御の実行中にも前輪の制動力の補填増加は行われないが、上述の第一の実施形態の場合と同様、前後輪の制動力の関係は図７に於いて実線にて示された関係になり、従来の場合に比して理想前後配分線に近くなるので、従来の場合に比して制動力の前後配分比を適正に制御することができる。
【００８０】
また一般に、車速Ｖが高くなるにつれて後輪に比して前輪のブレーキの効きが低下し、結果的に制動力の前後配分が後輪寄りになるので、車速Ｖが高いほど前輪の制動力の付加が早く開始され、車速Ｖが高いほど前輪の制動力の付加量が大きいことが好ましい。また一般に、車輌の積載荷重が高いほど制動力の理想前後配分線は後輪寄りになり、車輌の積載荷重が高いほど車輌の減速度が低くなるので、車輌の減速度が低いほど前輪の制動力の付加が遅く開始され、車輌の減速度が低いほど前輪の制動力の付加量が大きいことが好ましい。更に車輌の横加速度の大きさが大きいほど車輌が不安定になり易いので、車輌の横加速度の大きさが大きいほど前輪の制動力の付加が早く開始され、車輌の横加速度の大きさが大きいほど前輪の制動力の付加量が大きいことが好ましい。
【００８１】
上述の第一及び第二の実施形態によれば、前輪の制動力の付加を開始すべきか否かの判定の基準値Ｐmoはステップ２０に於いて車速Ｖ、車輌の減速度Ｇxb、車輌の横加速度Ｇyを変数とする関数Ｆp（Ｖ，Ｇxb，Ｇy）により、車速Ｖが高く車輌の横加速度Ｇyの大きさが大きいほど小さく、車輌の減速度Ｇxbが小さいほど大きく演算されるので、車速Ｖが高く車輌の横加速度Ｇyの大きさが大きいほど前輪の制動力の付加を早く開始して車輌が不安定になることを早期に防止し、車輌の積載荷重が高いことに起因して車輌の減速度が低い状況に於いて前輪の制動力が早期に過剰に増大することを確実に防止することができる。
【００８２】
上述の第一及び第二の実施形態によれば、前輪の目標制動圧Ｐtfはステップ４０に於いてマスタシリンダ圧力Ｐm、車速Ｖ、車輌の減速度Ｇxb、車輌の横加速度Ｇyを変数とする関数Ｆf（Ｐm，Ｖ，Ｇxb，Ｇy）により演算され、前輪の制動力の付加量を決定する係数Ｋは車速Ｖが高いほど大きく、車輌の減速度Ｇxbが小さいほど大きく、車輌の横加速度Ｇyの大きさが大きいほど大きくなるよう可変設定されるので、車速Ｖが高く車輌の横加速度Ｇyの大きさが大きいほど前輪の制動力の付加量を大きくして車輌が不安定になることを効果的に防止し、車輌の積載荷重が高いことに起因して車輌の減速度が低い状況に於いて前輪の負担が過剰に大きくなることを防止しつつ車輌全体の制動力が不足することに起因して車輌の減速度が不足することを確実に防止することができる。
【００８３】
また上述の第一及び第二の実施形態によれば、マスタシリンダ圧力Ｐmが基準値Ｐmo以上になると、マスタシリンダ圧力Ｐmの上昇につれて前輪の目標制動圧Ｐtfが漸次増大されることにより、運転者の制動操作量の増大につれて前輪の制動力の付加量が漸次増大されるので、例えば前輪の制動力の付加量が一定である場合に比して前輪の制動力の付加が開始される際の制動力の急変を確実に防止することができると共に、また運転者の制動操作量が高くなり後輪が前輪よりも先行してロック状態になる虞れが高くなるにつれて制動力の前後配分を漸次前輪寄りに制御することができる。
【００８４】
以上に於いては本発明を特定の実施形態について詳細に説明したが、本発明は上述の実施形態に限定されるものではなく、本発明の範囲内にて他の種々の実施形態が可能であることは当業者にとって明らかであろう。
【００８５】
例えば図示の各実施形態に於いては、前輪の制動力の付加を開始すべきか否かの判定の基準値Ｐmoは車速Ｖが高く車輌の横加速度Ｇyの大きさが大きいほど小さく、車輌の減速度Ｇxbが小さいほど大きく演算されるようになっているが、車速Ｖ、車輌の横加速度Ｇy、車輌の減速度Ｇxbの何れかが省略されてもよく、また基準値Ｐmoが一定の値に設定されるよう修正されてもよい。
【００８６】
また図示の各実施形態に於いては、前輪の制動力の付加量を決定する係数Ｋは車速Ｖが高いほど大きく、車輌の減速度Ｇxbが小さいほど大きく、車輌の横加速度Ｇyの大きさが大きいほど大きくなるよう可変設定されるようになっているが、この場合にも車速Ｖ、車輌の横加速度Ｇy、車輌の減速度Ｇxbの何れかが省略されてもよく、また係数Ｋが一定の値に設定されるよう修正されてもよい。
【００８７】
また図示の各実施形態に於いては、マスタシリンダ圧力Ｐmが基準値Ｐmo以上になると、前輪の目標制動圧Ｐtfがマスタシリンダ圧力Ｐmに対しＫ倍に増圧されることにより、マスタシリンダ圧力Ｐmの上昇に伴って前輪の制動力が線形的に増大するようになっているが、例えばマスタシリンダ圧力Ｐmが高くなるほど前輪の制動力の付加量が増大するよう、マスタシリンダ圧力Ｐmの上昇に伴って前輪の制動力が非線形的に増大するよう修正されてもよく、マスタシリンダ圧力Ｐmが後輪の保持圧力Ｐc以上の範囲に於いてはマスタシリンダ圧力Ｐmが上昇しても前輪の制動力が増大しないよう修正されてもよい。
【００８８】
また図示の各実施形態に於いては、マスタシリンダ圧力Ｐmが基準値Ｐmo以上の領域に於いては、マスタシリンダ圧力Ｐmが基準値Ｐmo未満の領域に比してマスタシリンダ圧力Ｐm、即ち運転者の制動操作量に対する車輌全体の制動力の比が高くなるので、例えばマスタシリンダ圧力Ｐmが基準値Ｐmo以上の領域に於いてペダルストロークに対するマスタシリンダ圧力Ｐmの上昇の比が小さくなるペダル比可変のブレーキペダルが採用され、これにより運転者の制動操作量に拘わらずペダルストロークに対する車輌全体の制動力の比を一定にして制動時のフィーリングが更に一層向上するよう構成されてもよい。
【００８９】
また図示の各実施形態に於いては、後輪の目標制動圧Ｐtrはマスタシリンダ圧力Ｐmのみに基づいて演算されるようになっているが、例えば車輌の横加速度Ｇyの大きさが大きいほど、即ち車輌が不安定になり易いほど小さくなるよう、マスタシリンダ圧力Ｐm及び車輌の横加速度Ｇyに基づいて演算されるよう修正されてもよい。
【００９０】
また図示の各実施形態に於いては、後輪の保持圧力Ｐcは予め設定された定数であるが、例えば車速Ｖが高いほど大きくなり、車輌の減速度Ｇxbが小さいほど大きくなるよう、車速Ｖ若しくは車輌の減速度Ｇxbに応じて可変設定されるよう修正されてもよい。
【００９１】
また図示の各実施形態に於いては、制動力の前後輪配分制御中には後輪の制動圧がその保持圧力Ｐcの一定の値に保持されるようになっているが、例えば前後輪のスリップ状態に応じて後輪の保持圧力Ｐcが漸減又は漸増されることにより後輪の制動圧が漸減又はパルス増圧により漸増されてもよい。
【００９２】
また上述の各実施形態に於いては、前輪制動力の付加中及び制動力の前後輪配分制御中には左右前輪及び左右後輪はそれぞれ互いに同一の圧力に制御されるようになっているが、例えば車輌の旋回状況や車輌の挙動に応じて左右前輪の制動圧若しくは左右後輪の制動圧が相互に異なる値に制御されるよう修正されてもよい。
【００９３】
更に上述の各実施形態に於いては、左右前輪及び左右後輪がそれぞれ１系統をなし各系統の制動圧が主として連通制御弁２２Ｆ、２２Ｒにより制御される制動装置であるが、本発明の制動制御装置が適用される制動装置は前輪の制動圧をマスタシリンダ圧力よりも高い値に制御することができ、後輪の制動圧をマスタシリンダ圧力よりも低い値に制御することができるものである限り、当技術分野に於いて公知の任意の構成のものであってよい。
【図面の簡単な説明】
【図１】本発明による制動制御装置の第一の実施形態の油圧回路及び電子制御装置を示す概略構成図である。
【図２】図１に示された前輪用の連通制御弁を示す解図的断面図である。
【図３】第一の実施形態に於ける前後輪の制動力配分制御ルーチンを示すフローチャートである。
【図４】第一の実施形態に於けるマスタシリンダ圧力Ｐmと前輪の目標制動圧Ｐtf及び後輪の目標制動圧Ｐtrとの間の関係を示すグラフである。
【図５】車速Ｖとブレーキ効き係数ＢＥＦとの間の関係を示すグラフである。
【図６】第一の実施形態に於けるマスタシリンダ圧力Ｐmと前輪の最終目標制動圧Ｐttf及び後輪の最終目標制動圧Ｐttrとの間の関係を示すグラフである。
【図７】理想前後配分線及び第一の実施形態に於ける前輪の制動圧Ｐfと後輪の制動圧Ｐrとの関係（実線）を従来技術の場合（破線）と対比して示すグラフである。
【図８】第二の実施形態に於ける前後輪の制動力配分制御ルーチンを示すフローチャートである。
【図９】第二の実施形態に於けるマスタシリンダ圧力Ｐmと前輪の最終目標制動圧Ｐttf及び後輪の最終目標制動圧Ｐttrとの間の関係を示すグラフである。
【符号の説明】
１０…制動装置
１４…マスタシリンダ
２２Ｆ、２２Ｒ…連通制御弁
２６FL、２６FR、２６RL、２６RR…ホイールシリンダ
４２Ｆ、４２Ｒ…オイルポンプ
２８FL〜２８RR、３４FL〜３４RR…開閉弁
４２Ｆ、４２Ｒ…ポンプ
６０Ｆ、６０Ｒ…吸入制御弁
７０…弁室
７４…弁要素
８４…圧縮コイルばね
８８…逆止弁
９０…電子制御装置
９６…圧力センサ
９８…車速センサ
１００…前後加速度センサ
１０２…横加速度センサ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a braking control device for a vehicle such as an automobile, and more particularly to a braking control device for a vehicle that performs braking force distribution control of front and rear wheels.
[0002]
[Prior art]
As one of braking control devices for vehicles such as automobiles, for example, as described in Japanese Patent Application Laid-Open No. 10-338115 filed by the applicant of the present application, the vehicle prevents the rear wheels from locking when braking the vehicle. In order to improve the running stability of the vehicle, the front / rear wheel braking force distribution control that suppresses the increase in the braking force of the rear wheel by holding or reducing the braking pressure of the rear wheel or increasing the pulse when the driving state of the vehicle reaches a predetermined state 2. Description of the Related Art A braking control device configured to perform the above is conventionally known.
[0003]
According to this type of braking control device, the rear wheels are locked before the front wheels and the stability of the vehicle due to this compared to the case where front and rear wheel braking force distribution control is not performed. Since the possibility of deterioration of the vehicle can be reduced, the running stability of the vehicle can be improved.
[0004]
[Problems to be solved by the invention]
However, in the braking control device that performs front and rear wheel braking force distribution control as described in the above publication, when the front and rear wheel braking force distribution control is executed, an increase in the braking force of the rear wheels is suppressed. Even if the driver increases the amount of braking operation in order to increase the braking force, the braking force of the vehicle as a whole does not increase sufficiently, and there is a problem that the braking operation feeling is poor.
[0005]
The present invention has been made in view of the above-described problems in the conventional braking control device configured to perform front and rear wheel braking force distribution control that suppresses an increase in the braking force of the rear wheels when the driving state of the vehicle becomes a predetermined state. The main object of the present invention is to make the braking force of the front wheels relatively lower than the braking force of the rear wheels in the braking operation region lower than the braking operation region where the front and rear wheel braking force distribution control is performed. By increasing the height, it is possible to prevent the rear wheel from being locked prior to the front wheel and to prevent the deterioration of the vehicle stability due to this, while maintaining the braking operation fee due to the front and rear wheel braking force distribution control. This is to reduce the possibility of deterioration of the ring.
[0006]
[Means for Solving the Problems]
  According to the present invention, the above-mentioned main problem is that the braking force is generated by supplying the hydraulic fluid pressure of the master cylinder to the wheel cylinder of the braking force generator provided corresponding to each wheel. When the vehicle driving state reaches a predetermined state, the vehicle braking control device performs the front-rear wheel braking force distribution control that suppresses the increase in the braking force of the rear wheels. Front wheel braking force adding means for making the braking force of the front wheels higher than the braking force corresponding to the amount of braking operation by the driver in the area below the area where the front and rear wheel braking force distribution control is performed.The front wheel braking force adding means makes the front wheel braking force higher than the braking force corresponding to the driver's braking operation amount when the driver's braking operation amount is greater than or equal to the reference value, and sets the reference value to the vehicle's braking operation amount. Change according to stateThis is achieved by a vehicle brake control device.
[0009]
  According to the present invention, in order to effectively achieve the main problem described above, in the configuration of claim 1, the front wheel braking force adding means sets the amount of increasing the braking force of the front wheel to the state of the vehicle. Configured to change accordingly (claims)2Configuration).
  According to the present invention, in order to effectively achieve the main problem described above, in the configuration of claim 2, the front wheel braking force adding means increases the braking force of the front wheel as the vehicle speed increases. The amount of increase in the braking force of the front wheels is variably set according to the vehicle speed so as to increase (configuration of claim 3).
  According to the present invention, in order to effectively achieve the above main problems, in the configuration of claim 2 or 3, the front wheel braking force adding means is configured such that the lower the vehicle deceleration, the lower the braking force of the front wheels. The amount of increasing the braking force of the front wheels is variably set according to the deceleration of the vehicle so that the amount of increasing the amount increases.
  According to the present invention, in order to effectively achieve the main problem described above, in the structure according to any one of claims 2 to 4, the front wheel braking force adding means has a lateral acceleration magnitude of the vehicle. The amount of increase in the braking force of the front wheels is variably set according to the lateral acceleration of the vehicle so that the amount of increase in the braking force of the front wheels increases as the value increases.
[0010]
  According to the present invention, in order to effectively achieve the main problems described above,Any one of 1 to 5The front wheel braking force adding means is configured to increase the amount by which the braking force of the front wheels is increased as the amount of braking operation by the driver increases.6Configuration).
  According to the present invention, in order to effectively achieve the above-mentioned main problems, in the configuration according to any one of the above claims 1 to 6, the front wheel braking force adding means has the reference value that increases as the vehicle speed increases. The reference value is variably set in accordance with the vehicle speed so as to be reduced (configuration of claim 7).
  Further, according to the present invention, in order to effectively achieve the main problem described above, in the configuration according to any one of claims 1 to 7, the front wheel braking force adding means has a lower vehicle deceleration. An amount for variably setting the reference value according to the deceleration of the vehicle is variably set so that the reference value is increased (configuration of claim 8).
  Further, according to the present invention, in order to effectively achieve the main problem described above, in the configuration according to any one of claims 1 to 8, the front wheel braking force adding means has a lateral acceleration magnitude of the vehicle. The reference value is variably set according to the lateral acceleration of the vehicle so that the reference value decreases as the value increases.
[0011]
[Action and effect of the invention]
  According to the first aspect of the present invention, the braking force of the front wheels is added to the area below the area where the front / rear wheel braking force distribution control is performed in view of the amount of braking operation of the driver. Therefore, the front / rear wheel distribution of the braking force is controlled to be closer to the front wheels in advance than the front / rear wheel braking force distribution control, so that the driver is compared with the case where the front wheel braking force is not increased. Even in a region where the amount of braking operation of the vehicle is relatively high, it is possible to reduce the possibility that the rear wheel is locked before the front wheel and the stability of the vehicle is deteriorated due to this, Compared with the case where the braking force of the front wheels is not increased, the region where the front and rear wheel braking force distribution control should be performed can be made a region where the driver's braking operation amount is high, and therefore the front and rear wheel braking force distribution control is performed. No braking operation area widened, thereby Rear wheel braking force braking operation feeling due to the distribution control can be reduced possibility to deteriorate.
  Further, according to the configuration of the first aspect, the braking force of the front wheels is made higher than the braking force corresponding to the amount of braking operation of the driver when the amount of braking operation of the driver is greater than or equal to the reference value. In a situation where the amount of braking operation is equal to or greater than the reference value, the braking force of the front wheels can be reliably made higher than the braking force corresponding to the amount of braking operation of the driver, and the addition of the braking force of the front wheels is not necessary. In the situation, it is possible to reliably prevent the braking force of the front wheels from being unnecessarily higher than the braking force corresponding to the braking operation amount of the driver.
  Further, according to the first aspect of the present invention, since the reference value is changed according to the state of the vehicle, the start of the application of the braking force of the front wheels when the amount of braking operation by the driver increases is determined by the state of the vehicle. It is possible to control accurately according to.
[0014]
  And the above claims2With this configuration, the amount of increase in the braking force of the front wheels is changed according to the state of the vehicle, so that the additional amount of the braking force of the front wheels can be accurately controlled according to the state of the vehicle. The braking force of the front wheels can be increased with an appropriate additional amount according to the state of the vehicle.
  According to the configuration of the third aspect, the amount of increasing the braking force of the front wheels is variably set according to the vehicle speed so that the amount of increasing the braking force of the front wheels increases as the vehicle speed increases. It is possible to effectively prevent the vehicle from becoming unstable by increasing the amount of braking force applied to the front wheels.
  According to the fourth aspect of the present invention, the amount of increase in the braking force of the front wheels is variably set in accordance with the deceleration of the vehicle so that the amount of increase in the braking force of the front wheels increases as the vehicle deceleration decreases. Therefore, in a situation where the deceleration of the vehicle is low due to a high vehicle load, it is possible to reliably prevent the vehicle deceleration from being insufficient due to insufficient braking force of the entire vehicle. Can do.
  According to the fifth aspect of the present invention, the amount by which the braking force of the front wheels is increased according to the lateral acceleration of the vehicle is variable so that the amount of increase of the braking force of the front wheels increases as the lateral acceleration of the vehicle increases. Therefore, the larger the lateral acceleration of the vehicle is, the larger the amount of braking force applied to the front wheels can be increased to effectively prevent the vehicle from becoming unstable.
[0015]
  And the above claims6With this configuration, as the amount of braking operation by the driver increases, the amount of increase in the braking force of the front wheels is increased. For example, compared with the case where the amount of addition of the braking force of the front wheels is constant, Sudden changes in braking force at the start of power addition can be reliably prevented, and as the amount of braking operation by the driver increases, that is, the rear wheels may become locked before the front wheels. As the engine speed increases, the front-rear distribution of the braking force can be gradually controlled closer to the front wheels.
  According to the configuration of the seventh aspect, since the reference value is variably set according to the vehicle speed so that the reference value decreases as the vehicle speed increases, the braking force of the front wheels is started earlier as the vehicle speed increases. Can be prevented at an early stage.
  According to the eighth aspect of the invention, since the reference value is variably set according to the deceleration of the vehicle so that the reference value increases as the vehicle deceleration decreases, the vehicle load is high and the vehicle deceleration is increased. It is possible to reliably prevent the braking force of the front wheels from increasing excessively at an early stage in a situation where the engine speed is low.
  According to the ninth aspect of the present invention, the reference value is variably set according to the lateral acceleration of the vehicle so that the reference value decreases as the lateral acceleration of the vehicle increases. It is possible to prevent the vehicle from becoming unstable at an early stage by increasing the braking force of the wheel as the value of is larger.
[0016]
[Preferred embodiment of the problem solving means]
According to one preferred aspect of the present invention, in the configuration of claim 1, the front wheel braking force adding means includes a region where the braking operation amount of the driver is smaller than a region where the front and rear wheel braking force distribution control is performed, and the front and rear In a region where the wheel braking force distribution control is performed, the front wheel braking force is configured to be higher than the braking force corresponding to the braking operation amount of the driver (preferred aspect 1).
[0021]
  According to another preferred embodiment of the present invention, the above claims 1 toAny of 9In this configuration, when the front-rear wheel braking force distribution control is being performed, the front wheel braking force is increased in accordance with the increase suppression amount of the rear wheel braking force (preferred embodiment).2).
[0022]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described in detail with reference to a few preferred embodiments with reference to the accompanying drawings.
[0023]
First embodiment
FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electronic control device of a first embodiment of a braking control device according to the present invention, and FIG. 2 is an illustrative sectional view showing a front wheel communication control valve shown in FIG. It is. In FIG. 1, the solenoid of each valve that is electromagnetically driven is not shown.
[0024]
In FIG. 1, reference numeral 10 denotes a hydraulic braking device, and the braking device 10 has a master cylinder 14 that pumps brake oil in response to a depression operation of a brake pedal 12 by a driver. The master cylinder 14 has a first master cylinder chamber 14A and a second master cylinder chamber 14B defined by free pistons 16 biased to predetermined positions by compression coil springs on both sides thereof.
[0025]
One end of a front wheel brake hydraulic control conduit 18F is connected to the first master cylinder chamber 14A, and the other brake brake control conduit 18F is connected to the left front wheel brake hydraulic control conduit 20FL and the right front wheel brake hydraulic control. One end of the conduit 20FR is connected. A communication control valve 22F for the front wheels is provided in the middle of the brake hydraulic control conduit 18F, and the communication control valve 22F is a normally open linear solenoid valve in the illustrated embodiment. Connected to the brake hydraulic control conduits 18F on both sides of the communication control valve 22F are check bypass conduits 24F that permit only the flow of oil from the first master cylinder chamber 14A toward the brake hydraulic control conduit 20FL or the brake hydraulic control conduit 20FR. Yes.
[0026]
As shown schematically in FIG. 2, the communication control valve 22F has a housing 72 that defines a valve chamber 70 therein, and a valve element 74 is disposed in the valve chamber 70 so as to be capable of reciprocating. . A portion 18FA of the brake hydraulic pressure control conduit 18F on the master cylinder 14 side is always connected to the valve chamber 70 via an internal passage 76, and a portion 18FB of the brake hydraulic pressure control conduit 18F opposite to the master cylinder 14 is internally connected. A communication connection is established via a passage 78 and a port 80.
[0027]
As shown in the figure, a solenoid 82 is disposed around the valve element 74, and the valve element 74 is urged to a valve opening position shown in FIG. 2 by a compression coil spring 84. When a drive voltage is applied to the solenoid 82, the valve element 74 is urged against the port 80 against the spring force of the compression coil spring 84, thereby closing the port 80.
[0028]
In the situation where the communication control valve 22F is in the closed position, the sum of the force of the pressure in the portion 18FB on the opposite side of the master cylinder 14 of the brake hydraulic control conduit 18F and the spring force of the compression coil spring 84 is the solenoid. When the electromagnetic force is increased by the pressure 82, the valve element 74 opens away from the port 80, and the oil in the portion 18FB passes through the internal passage 78, the port 80, the valve chamber 70, the internal passage 76, and the brake hydraulic control conduit 18F. To the part 18FA. When the oil pressure in the portion 18FB decreases due to this oil flow, the sum of the force by the pressure and the spring force of the compression coil spring 84 becomes lower than the electromagnetic force by the solenoid 82, and the valve element 74 causes the port 80 to Close again.
[0029]
Thus, since the communication control valve 22F controls the pressure in the portion 18FB of the brake hydraulic pressure control conduit 18F according to the voltage applied to the solenoid 82, the communication control valve 22F controls the pressure in the portion 18FB by controlling the driving voltage for the solenoid 82. The pressure (referred to herein as “upstream pressure”) can be controlled to a desired pressure.
[0030]
In the illustrated embodiment, the check bypass conduit 24F shown in FIG. 1 is built in the communication control valve 22F, and is provided with an internal passage 86 and a part from the valve chamber 70 provided in the middle of the internal passage. It consists of a check valve 88 that allows only the flow of oil toward 18FB.
[0031]
A brake force generator wheel not shown in FIG. 1 generates braking force for the left front wheel and right front wheel at the other ends of the brake hydraulic control conduit 20FL for the left front wheel and the brake hydraulic control conduit 20FR for the right front wheel, respectively. Cylinders 26FL and 26FR are connected, and normally open electromagnetic on-off valves 28FL and 28FR are provided in the middle of the brake hydraulic control conduit 20FL for the left front wheel and the brake hydraulic control conduit 20FR for the right front wheel, respectively. Connected to the brake hydraulic control conduits 20FL and 20FR on both sides of the electromagnetic on-off valves 28FL and 28FR are check bypass conduits 30FL and 30FR that permit only the flow of oil from the wheel cylinders 26FL and 26FR toward the brake hydraulic control conduit 18F, respectively. .
[0032]
One end of an oil discharge conduit 32FL is connected to the brake hydraulic control conduit 20FL between the electromagnetic on-off valve 28FL and the wheel cylinder 26FL, and oil is discharged to the brake hydraulic control conduit 20FR between the electromagnetic on-off valve 28FR and the wheel cylinder 26FR. One end of the conduit 32FR is connected. Normally closed solenoid valves 34FL and 34FR are provided in the middle of the oil discharge conduits 32FL and 32FR, respectively, and the other ends of the oil discharge conduits 32FL and 32FR are connected to a front wheel buffer reservoir 38F by a connection conduit 36F. ing.
[0033]
As understood from the above description, the electromagnetic on-off valves 28FL and 28FR are pressure-increasing valves for increasing or maintaining the pressure in the wheel cylinders 26FL and 26FR, respectively, and the electromagnetic on-off valves 34FL and 34FR are in the wheel cylinders 26FL and 26FR, respectively. Therefore, the electromagnetic on-off valves 28FL and 34FL cooperate with each other to define an increasing / decreasing valve for increasing and decreasing the pressure in the wheel cylinder 26FL of the left front wheel, The electromagnetic open / close valves 28FR and 34FR cooperate with each other to define a pressure increasing / reducing valve for increasing and decreasing the pressure in the wheel cylinder 26FR of the right front wheel.
[0034]
The connection conduit 36F is connected to the suction side of the pump 42F by the connection conduit 40F, and two check valves 44F and 46F that allow only the flow of oil from the connection conduit 36F to the pump 42F are provided in the connection conduit 40F. It has been. The discharge side of the pump 42F is connected to the brake hydraulic control conduit 18F by a connection conduit 50F having a damper 48F on the way. A connection conduit 50F between the pump 42F and the damper 48F is provided with a check valve 52F that allows only the flow of oil from the pump 42F toward the damper 48F.
[0035]
One end of a connection conduit 54F is connected to the connection conduit 40F between the two check valves 44F and 46F, and the other end of the connection conduit 54F is a brake between the first master cylinder chamber 14A and the control valve 22F. It is connected to the hydraulic control conduit 18F. A normally closed electromagnetic on-off valve 60F is provided in the middle of the connecting conduit 54F. The electromagnetic on-off valve 60F functions as a suction control valve that controls communication between the brake hydraulic pressure control conduit 18F between the master cylinder 14 and the control valve 22F and the suction side of the pump 42F.
[0036]
Similarly, one end of a brake oil pressure control conduit 18R for the rear wheel is connected to the second master cylinder chamber 14B, and the brake oil pressure control conduit 20RL for the left rear wheel and the right rear wheel are connected to the other end of the brake oil pressure control conduit 18R. One end of a brake hydraulic control conduit 20RR for the wheel is connected. A rear wheel communication control valve 22R, which is a normally open linear solenoid valve, is provided in the middle of the brake hydraulic control conduit 18R.
[0037]
The communication control valve 22R has the same structure as that shown in FIG. 2 with respect to the front wheel communication control valve 22F. Therefore, the communication control valve 22R is controlled by controlling the drive voltage for the solenoid not shown in the figure. The pressure (upstream pressure) in the brake hydraulic pressure control conduit 18R downstream of the valve 22R can be controlled to a desired pressure. Further, a check bypass conduit 24R allowing only the flow of oil from the second master cylinder chamber 14B to the brake hydraulic control conduit 20RL or the brake hydraulic control conduit 20RR is connected to the brake hydraulic control conduit 18R on both sides of the communication control valve 22R. ing.
[0038]
A braking force not shown in FIG. 1 is generated at the other ends of the brake hydraulic control conduit 20RL for the left rear wheel and the brake hydraulic control conduit 20RR for the right rear wheel, respectively. The wheel cylinders 26RL and 26RR of the generator are connected, and normally open type electromagnetic on-off valves 28RL and 28RR are provided in the middle of the brake hydraulic control conduit 20RL for the left rear wheel and the brake hydraulic control conduit 20RR for the right rear wheel, respectively. Is provided. Connected to the brake hydraulic control conduits 20RL and 20RR on both sides of the electromagnetic on-off valves 28RL and 28RR are check bypass conduits 30RL and 30RR that permit only the flow of oil from the wheel cylinders 26RL and 26RR toward the brake hydraulic control conduit 18R, respectively. .
[0039]
One end of an oil discharge conduit 32RL is connected to the brake hydraulic control conduit 20RL between the electromagnetic on-off valve 28RL and the wheel cylinder 26RL, and oil is discharged to the brake hydraulic control conduit 20RR between the electromagnetic on-off valve 28RR and the wheel cylinder 26RR. One end of the conduit 32RR is connected. In the middle of the oil discharge conduits 32RL and 32RR, normally closed electromagnetic on-off valves 34RL and 34RR are provided, respectively, and the other ends of the oil discharge conduits 32RL and 32RR are connected to a rear wheel buffer reservoir 38R by a connection conduit 36R. Has been.
[0040]
As in the case of the front wheel side, the electromagnetic on-off valves 28RL and 28RR are pressure-increasing valves for increasing or maintaining the pressure in the wheel cylinders 26RL and 26RR, respectively. The electromagnetic on-off valves 34RL and 34RR are in the wheel cylinders 26RL and 26RR, respectively. Therefore, the electromagnetic on-off valves 28RL and 34RL cooperate with each other to define an increase / decrease valve for increasing and decreasing the pressure in the wheel cylinder 26RL of the left rear wheel. The electromagnetic on-off valves 28RR and 34RR cooperate with each other to define an increasing / decreasing valve for increasing and decreasing the pressure in the wheel cylinder 26RR of the right rear wheel.
[0041]
The connecting conduit 36R is connected to the suction side of the pump 42R by a connecting conduit 40R, and two check valves 44R and 46R that allow only the flow of oil from the connecting conduit 36R to the pump 42R are provided in the connecting conduit 40R. It has been. The discharge side of the pump 42R is connected to the brake hydraulic control conduit 18R by a connection conduit 50R having a damper 48R on the way. A connection conduit 50R between the pump 42R and the damper 48R is provided with a check valve 52R that allows only an oil flow from the pump 42R to the damper 48R. The pumps 42F and 42R are driven by a common electric motor not shown in FIG.
[0042]
One end of a connection conduit 54R is connected to the connection conduit 40R between the two check valves 44R and 46R, and the other end of the connection conduit 54R is a brake between the second master cylinder chamber 14B and the control valve 22R. It is connected to the hydraulic control conduit 18R. A normally closed electromagnetic on-off valve 60R is provided in the middle of the connecting conduit 54R. This electromagnetic on-off valve 60R also functions as a suction control valve that controls communication between the brake hydraulic pressure control conduit 18R between the master cylinder 14 and the control valve 22R and the suction side of the pump 42R.
[0043]
In the illustrated embodiment, each control valve and each on-off valve is set to the non-control position shown in FIG. 1 when the drive current is not applied to the corresponding solenoid, whereby the wheel cylinders 26FL and 26FR are set. The pressure in the first master cylinder chamber 14A is supplied, and the pressure in the second master cylinder chamber 14B is supplied to the wheel cylinders 26RL and 26RR. Therefore, at normal times, the pressure in the wheel cylinder of each wheel, that is, the braking force is increased or decreased according to the depression force of the brake pedal 12.
[0044]
On the other hand, the communication control valves 22F and 22R are switched to the closed position, the on-off valves 60F and 60R are opened, and the pumps 42F and 42R are operated in a state where the on-off valves of the wheels are at the positions shown in FIG. When driven, the oil in the master cylinder 14 is pumped up by the pump, the pressure pumped up by the pump 42F is supplied to the wheel cylinders 26FL, 26FR, and the pumping up by the pump 42R is supplied to the wheel cylinders 26RL, 26RR. Since the pressure is supplied, the braking pressure of each wheel is increased / decreased by opening / closing the communication control valves 22F, 22R and the opening / closing valves (increasing / reducing valves) of each wheel regardless of the depression force of the brake pedal 12.
[0045]
In this case, the pressure in the wheel cylinder is increased when the on-off valves 28FL to 28RR and the on-off valves 34FL to 34RR are in the non-control position shown in FIG. 1 (pressure increasing mode), and the on-off valves 28FL to 28RR are closed. When it is switched to the valve position and the on-off valves 34FL to 34RR are in the non-control position shown in FIG. 1, it is held (holding mode), and the on-off valves 28FL to 28RR and the on-off valves 34FL to 34RR are switched to the open position. The pressure is reduced (pressure reduction mode).
[0046]
The communication control valves 22F and 22R, the open / close valves 28FL to 28RR, the open / close valves 34FL to 34RR, and the open / close valves 60F and 60R are controlled by the electronic control unit 90 as described later. The electronic control unit 90 includes a microcomputer 92 and a drive circuit 94, and the microcomputer 92 may have a general configuration well known in the art.
[0047]
The microcomputer 92 indicates a signal indicating the master cylinder pressure Pm from the pressure sensor 96, a signal indicating the vehicle speed V from the vehicle speed sensor 98, a longitudinal acceleration Gx of the vehicle from the longitudinal acceleration sensor 100, and a lateral acceleration Gy of the vehicle from the lateral acceleration sensor 102. A signal is input. The microcomputer 92 stores a braking control flow, which will be described later, and controls the braking pressure Pi (i = fl, fr, rl, rr) of each wheel according to the braking control flow.
[0048]
In particular, in the illustrated embodiment, when the amount of braking operation by the driver is small and the front / rear distribution control of the braking force is unnecessary, the communication control valve 22F and the like are maintained in the illustrated standard position and the pumps 42F and 42R are driven. Accordingly, the braking pressure of each wheel, that is, the pressure in the wheel cylinders 26FL to 26RR is controlled by the master cylinder pressure Pm.
[0049]
On the other hand, when the amount of braking operation by the driver is large and it is necessary to suppress the increase in the braking force of the rear wheels by the braking force front-rear distribution control, the left and right rear wheel on-off valves 28RL and 28RR are closed to The rear wheel braking pressure is maintained at a constant value. Simultaneously, the communication control valve 22F is closed, the suction control valve 60F is opened, the pump 42F is driven, and the communication control valve 22F is controlled. The braking pressure of the left and right front wheels is increased, and thereby the braking force deficiency due to the braking pressure of the rear wheels being held at a constant value is supplemented by the increase of the braking force of the front wheels.
[0050]
Further, in the illustrated embodiment, the communication control valve 22F is closed and the intake control valve 60F is opened in the braking operation region lower than the braking operation region in which the braking force front-rear distribution control is executed. As the pump 42F is driven and the communication control valve 22F is controlled, the braking pressure of the left and right front wheels is increased to a value higher than the master cylinder pressure Pm, as will be described in detail later. Prior to execution, the front and rear wheel distribution of the braking force is controlled in advance toward the front wheels.
[0051]
Although not shown in the figure, the electromagnetic on-off valves 28FL to 28RR and the on-off valves 34FL to 34RR are controlled, for example, when the behavior of the vehicle is stabilized by individually controlling the braking force of each wheel. Particularly in this case, the higher target braking pressure of the left and right wheels is set to the target upstream pressure Ptf, Ptr, and the braking pressure Pi of the wheel having the higher target braking pressure Pti of the left and right wheels is upstream by the communication control valve 22F or 22R. The pressure is controlled by controlling to the target upstream pressure Ptf or Ptr, and the braking pressure of the left and right wheels is controlled to the corresponding target braking pressure by the corresponding pressure increasing valve and the pressure reducing valve.
[0052]
Next, the braking control routine in the illustrated first embodiment will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 3 is started by closing an ignition switch not shown in the figure, and is repeatedly executed at predetermined time intervals.
[0053]
First, in step 10, a signal indicating the master cylinder pressure Pm detected by the pressure sensor 96 is read. In step 20, the vehicle speed V, the vehicle deceleration Gxb (= -Gx), the vehicle The reference value Pmo is calculated according to the following equation 1 using the function Fp (V, Gxb, Gy) with the lateral acceleration Gy as a variable. In this case, the reference value Pmo is a positive value that is smaller than the master cylinder pressure Pm in a region where the front and rear wheel braking force distribution control is performed by suppressing the braking force of the rear wheel, which will be described later, and is smaller as the vehicle speed V is higher. The smaller the deceleration Gxb is, the larger the calculation is, and the larger the lateral acceleration Gy of the vehicle is, the smaller the calculation is.
Pmo = Fp (V, Gxb, Gy) (1)
[0054]
In step 30, it is necessary to determine whether or not the master cylinder pressure Pm is equal to or higher than the reference value Pmo, that is, to add the braking force of the front wheels to control the front / rear wheel distribution ratio of the braking force closer to the front wheels in advance. When the negative determination is made, the control by the routine shown in FIG. 3 is once ended, and when the positive determination is made, the process proceeds to Step 40.
[0055]
In step 40, the target braking of the front wheels is performed according to the following equation 2 by the function Ff (Pm, V, Gxb, Gy) having the master cylinder pressure Pm, the vehicle speed V, the vehicle deceleration Gxb, and the vehicle lateral acceleration Gy as variables. The pressure Ptf is calculated, and the target braking pressure Ptr for the rear wheels is calculated according to the following equation 3 using a function Fr (Pm) with the master cylinder pressure Pm as a variable.
Ptf = Ff (Pm, V, Gxb, Gy) (2)
Ptr = Fr (Pm) (3)
[0056]
  For example, as shown in FIG. 4, the target braking pressure Ptf for the front wheels is calculated to the same value as the master cylinder pressure Pm when the master cylinder pressure Pm is less than the reference value Pmo. In the range above the value Pmo, the value is calculated by multiplying the master cylinder pressure Pm by a coefficient K greater than 1. The rear wheel target braking pressure Ptr is calculated to the same value as the master cylinder pressure Pm regardless of the value of the master cylinder pressure Pm. In this case, the coefficient K increases as the vehicle speed V increases.bigThe vehicle speed V, the vehicle deceleration Gxb, and the vehicle lateral acceleration Gy are variably set so as to increase as the vehicle deceleration Gxb decreases and increase as the vehicle lateral acceleration Gy increases.
[0057]
In step 50, it is determined whether or not the braking force distribution control of the front and rear wheels is being controlled by suppressing the braking force of the rear wheels, that is, after an affirmative determination is made in step 60 or 70 described later. In step 90, it is determined whether an affirmative determination is not made. If an affirmative determination is made, the process proceeds to step 90. If a negative determination is made, the process proceeds to step 60.
[0058]
In step 60, it is determined whether or not the master cylinder pressure Pm exceeds the rear wheel holding pressure Pc (a positive constant larger than Pmo), that is, the rear wheel braking pressure is held and the front wheel braking pressure is set. It is determined whether or not it is necessary to increase the compensation. If an affirmative determination is made, the process proceeds to step 110. If a negative determination is made, the process proceeds to step 70.
[0059]
In step 70, it is determined whether or not other starting conditions for the braking force distribution control for the front and rear wheels are established in any manner known in the art, and when a negative determination is made. In step 100, if an affirmative determination is made, in step 80, the holding pressure Pc of the rear wheel is set to the master cylinder pressure Pm at that time, and then the process proceeds to step 110.
[0060]
Whether or not other starting conditions for the braking force distribution control for the front and rear wheels are satisfied is determined by, for example, (A) Deviation ΔVw of the average wheel speed Vwr of the left and right rear wheels with respect to the average wheel speed Vwf of the left and right front wheels. Or (B) by determining whether the vehicle deceleration Gxb is equal to or greater than the control start reference value Gxs (positive constant). Or may be performed by a combination of the above (A) and (B).
[0061]
In step 90, for example, by determining whether or not the master cylinder pressure Pm has become equal to or less than the control end reference value Pme (a positive constant larger than Pmo and smaller than Pc), the braking force distribution control for the front and rear wheels is terminated. It is determined whether or not the condition is satisfied, and when an affirmative determination is made, in step 100, the front wheel braking pressure increase pressure ΔPf is set to 0, and the rear wheel target braking pressure Ptr is set to the master wheel. After the cylinder pressure Pm is set, the routine proceeds to step 130. When a negative determination is made, the routine proceeds to step 110.
[0062]
It should be noted that whether or not the condition for terminating the braking force distribution control for the front and rear wheels has been satisfied may be determined in any manner known in the art. When it is performed based on ΔVw, it may be performed by determining whether or not the wheel speed deviation ΔVw is equal to or less than the control end reference value Vwe (a positive constant smaller than Vws). When the establishment determination is made based on the vehicle deceleration Gxb, it may be performed by determining whether or not the vehicle deceleration Gxb is equal to or less than a control end reference value Gxe (a positive constant smaller than Gxs). .
[0063]
In step 110, the front wheel braking pressure is calculated according to the following equation (4) using the function Ffa (Ptr-Pc, V) with the deviation Ptr-Pc between the target braking pressure Ptr and the holding pressure Pc of the rear wheel and the vehicle speed V as variables. The increase pressure ΔPf is calculated, and in step 120, the target braking pressure Ptr for the rear wheels is set to the holding pressure Pc.
ΔPf = Ffa (Ptr−Pc, V) (4)
[0064]
For example, the front and rear wheel cylinder cross-sectional areas are Sf and Sr (positive constants), the front and rear wheel braking effective radii are Rf and Rr (positive constants), respectively, and the front and rear wheel braking effectiveness coefficients. BEFf and BEFr (positive constants) and BEFo as the standard braking effectiveness coefficient, the braking effectiveness coefficient BEFv corresponding to the current vehicle speed is calculated from the map corresponding to the graph shown in FIG. The increase pressure ΔPf of the braking pressure of the front wheels is calculated according to the following formula 5. The wheel cylinder cross-sectional areas Sf and Sr and the effective braking radii Rf and Rr are values determined by the specifications of the braking force generator, and the braking effectiveness coefficients BEFf and BEFr are obtained in advance experimentally, for example.
Figure 0003829926
[0065]
In step 130, the front wheel target pressure increase amount ΔPtf (the difference between the front wheel final target brake pressure Pttf (= Ptf + ΔPf) and the master cylinder pressure Pm) is calculated according to the following equation 6, and the rear wheel target pressure increase: The amount ΔPtr (deviation between the rear wheel final target braking pressure Pttr (= Ptr) and the master cylinder pressure Pm) is calculated according to the following equation (7).
ΔPtf = Ptf−Pm + ΔPf (6)
ΔPtr = Ptr−Pm (7)
[0066]
In step 140, the target current of the communication control valve 22F corresponding to the target pressure increase amount ΔPtf of the front wheels is calculated, and the communication control valve 22F is controlled by the corresponding target current, so that the braking pressures of the left and right front wheels are final. The front wheel system of the braking device 10 is controlled so that the target braking pressure Pttf is obtained. When the target pressure increase amount ΔPtr for the rear wheels is a negative value, the left and right rear wheel on-off valves 28RL and 28RR are closed, whereby the braking pressure for the left and right rear wheels is held at the holding pressure Pc. When the target pressure increase amount ΔPtr is 0, the left and right rear wheel on-off valves 28RL and 28RR are opened, whereby the braking device 10 is configured so that the braking pressure on the left and right rear wheels becomes the final target braking pressure Pttr (= Ptr). The rear wheel system is controlled.
[0067]
Although not shown in FIG. 3, if a negative determination is made in step 30 described above, the communication control valve 22F and the like are set to the standard positions shown in FIG. The wheel cylinders 26FR to 26RR are directly supplied with the pressure Pm of the master cylinder 14, whereby the braking pressure of each wheel is increased or decreased in accordance with the braking operation amount of the driver.
[0068]
Thus, according to the illustrated first embodiment, when the amount of braking operation is increased by the driver and the master cylinder pressure Pm becomes equal to or higher than the reference value Pmo, an affirmative determination is made in step 30, and in step 40. The target braking pressure Ptf for the front wheels is calculated to be higher than the master cylinder pressure Pm, and the target braking pressure Ptr for the rear wheels is calculated, so that the braking force for the front wheels is calculated prior to the start of the braking force distribution control for the front and rear wheels. Is added to control the front-rear wheel distribution ratio of the braking force closer to the front wheels in advance, and the possibility of the rear wheels locking prior to the front wheels is reduced.
[0069]
Therefore, as shown in FIG. 6, the holding pressure of the rear wheels is increased as compared with the conventional braking control device in which the braking force of the front wheels is not applied prior to the start of the braking force distribution control of the front and rear wheels. The braking operation range in which the braking force distribution control of the front and rear wheels is not performed can be widened, so that the vehicle can be braked by effectively using the braking force of the rear wheels, and the braking force of the front and rear wheels There is a risk that the braking force of the vehicle will be insufficient with respect to the amount of braking operation of the driver due to the distribution control being performed and the braking force of the rear wheel being suppressed, and this causes the driver to feel uncomfortable. The fear of feeling can be reduced.
[0070]
In particular, according to the illustrated first embodiment, when the amount of braking operation by the driver is further increased and the master cylinder pressure Pm becomes higher than the rear wheel holding pressure Pc, an affirmative determination is made in step 60, When another start condition of the braking force distribution control for the front and rear wheels is satisfied, an affirmative determination is made in step 70, and the braking pressure for the rear wheels is changed to the holding pressure Pc by the braking force distribution control for the front and rear wheels in step 110. An increase pressure ΔPf of the front wheel braking pressure for compensating for the shortage of the braking force due to being held in is calculated, and in steps 120 to 140, the braking pressure of the left and right front wheels is set to the final target braking pressure Pttf (= Ptf + ΔPf). And the braking pressure of the left and right rear wheels is held at the holding pressure Pc, whereby the braking force distribution control of the front and rear wheels is executed.
[0071]
Accordingly, by maintaining the braking pressure of the rear wheels at the holding pressure Pc in the region where the amount of braking operation by the driver is high, it is possible to effectively prevent the rear wheels from locking prior to the front wheels, Since the braking force deficiency due to the rear wheel braking pressure being held at the holding pressure Pc is compensated by the increase in the front wheel braking pressure, the braking force distribution range of the front and rear wheels is controlled to be relatively high. In this case, the braking force of the vehicle is insufficient with respect to the amount of braking operation of the driver due to the braking pressure of the rear wheel being held at the holding pressure Pc, and the driver feels uncomfortable due to this. It can be effectively prevented.
[0072]
Further, according to the first embodiment shown in the figure, when the master cylinder pressure Pm becomes equal to or higher than the reference value Pmo, the braking force of the front wheels is applied, so that the master cylinder pressure Pm is higher than the conventional rear wheel holding pressure Pc. Since the braking force distribution control of the front and rear wheels will not be started unless this is true, as shown in FIG. 7, the ideal front / rear distribution line compared to the conventional case where the relationship between the braking forces of the front and rear wheels is indicated by broken lines. This makes it possible to appropriately control the front / rear distribution ratio of the braking force as compared with the conventional case.
[0073]
Further, according to the first embodiment shown in the figure, the increase amount ΔPf of the braking pressure of the front wheels is not simply set to the suppression amount ΔPr (= Ptr−Pttr) of the braking pressure of the rear wheels. Since the braking force corresponding to the shortage of the rear wheel braking force due to pressure suppression is calculated as a value for adding to the front wheel braking force, the front wheel braking pressure is the master cylinder pressure Pma + rear wheel braking pressure suppression. Compared to the case where the amount is set to the amount ΔPr, it is possible to reliably reduce the possibility that the braking force of the entire vehicle is insufficient with respect to the braking operation amount of the driver due to the suppression of the braking pressure of the rear wheels.
[0074]
Further, according to the first embodiment shown in the drawing, the brake effect increasing pressure ΔPf is calculated in consideration of the fact that the braking effect coefficient BEF decreases as the vehicle speed V increases in step 110. Compared to the case where the variation of the coefficient BEF is not taken into account, the increase pressure ΔPf of the front wheel braking pressure can be calculated to a value that accurately corresponds to the shortage of the rear wheel braking force. It can be properly controlled without any shortage.
[0075]
Second embodiment
FIG. 8 is a flowchart showing a braking control routine in the second embodiment of the braking control apparatus according to the present invention. In FIG. 8, steps corresponding to the steps shown in FIG. 3 are given the same step numbers as those shown in FIG.
[0076]
In the second embodiment, steps 10 to 90 and steps 120 and 140 are executed in the same manner as in the first embodiment, and correspond to step 110 in the first embodiment. The step to do is not executed. When a negative determination is made at step 70 and when an affirmative determination is made at step 90, the routine proceeds to step 100, where the target braking pressure Ptr of the rear wheel is changed to the master cylinder pressure Pm. In step 130, the front wheel target pressure increase amount ΔPtf (the difference between the front wheel final target braking pressure Pttf (= Ptf) and the master cylinder pressure Pm) is calculated according to the following equation (8).
ΔPtf = Ptf−Pm (8)
[0077]
Thus, according to the second embodiment shown in the figure, as in the case of the first embodiment described above, when the master cylinder pressure Pm becomes equal to or higher than the reference value Pmo due to the increase of the braking operation amount by the driver, FIG. As shown in FIG. 2, the front wheel target braking pressure Ptf is calculated to be higher than the master cylinder pressure Pm, and the front wheel braking force is added prior to the start of front and rear wheel braking force distribution control. The distribution ratio is controlled in advance toward the front wheels.
[0078]
Accordingly, the braking operation range in which the braking force distribution control of the front and rear wheels is not performed can be widened to brake the vehicle effectively using the braking force of the rear wheels, and the braking force distribution control of the front and rear wheels is executed. This reduces the possibility that the braking force of the vehicle will be insufficient with respect to the amount of braking operation of the driver due to the suppression of the braking force of the driver, and that the driver may feel uncomfortable due to this. Can do.
[0079]
Further, according to the illustrated second embodiment, the front wheel braking force is not increased during the execution of the braking force distribution control for the front and rear wheels, but as in the case of the first embodiment described above, The relationship between the braking force of the wheels is the relationship indicated by the solid line in FIG. 7, and is closer to the ideal front-rear distribution line compared to the conventional case, so the front-rear distribution of braking force is compared to the conventional case. The ratio can be controlled appropriately.
[0080]
  In general, as the vehicle speed V increases, the braking effectiveness of the front wheels decreases as compared with the rear wheels. As a result, the front-rear distribution of the braking force becomes closer to the rear wheels. It is preferable that the addition is started earlier and the amount of addition of the braking force of the front wheels is larger as the vehicle speed V is higher. In general, the higher the vehicle load, the closer the ideal front-rear distribution line of braking force is to the rear wheels, and the higher the vehicle load, the lower the vehicle deceleration.RuThe lower the vehicle deceleration, the slower the front wheel braking force starts to be applied, and the lower the vehicle deceleration, the more the front wheel braking force applied.bigIt is preferable. Furthermore, the greater the lateral acceleration of the vehicle, the more likely the vehicle becomes unstable. Therefore, the greater the lateral acceleration of the vehicle, the faster the front wheel braking force is applied, and the greater the lateral acceleration of the vehicle. It is preferable that the amount of braking force applied to the front wheels is large.
[0081]
  According to the first and second embodiments described above, the reference value Pmo for determining whether or not to start applying the braking force of the front wheels is determined in step 20 as the vehicle speed V, the vehicle deceleration Gxb, the vehicle sideways. The function Fp (V, Gxb, Gy) with the acceleration Gy as a variable is calculated so that the smaller the vehicle speed Vy is, the smaller the vehicle lateral acceleration Gy is, and the smaller the vehicle deceleration Gxb is. The higher the vehicle's lateral acceleration Gy, the sooner the front wheel braking force is applied to prevent the vehicle from becoming unstable and the higher the vehicle load.Due to this, the vehicle deceleration is lowIn the situation of the front wheelsBraking forceButEarlyAn excessive increase can be surely prevented.
[0082]
  According to the first and second embodiments described above, the target braking pressure Ptf of the front wheels is a function in which the master cylinder pressure Pm, the vehicle speed V, the vehicle deceleration Gxb, and the vehicle lateral acceleration Gy are variables in step 40. The coefficient K that is calculated by Ff (Pm, V, Gxb, Gy) and determines the amount of braking force applied to the front wheels increases as the vehicle speed V increases.bigIn addition, since the vehicle deceleration Gxb is small and is set so as to increase as the vehicle lateral acceleration Gy increases, the front wheel control increases as the vehicle speed V increases and the vehicle lateral acceleration Gy increases. Effectively preventing the vehicle from becoming unstable by increasing the amount of power added, and the load capacity of the vehicle is highDue to this, the vehicle deceleration is lowThat the burden on the front wheels becomes excessive in the situation.Prevent the vehicle from slowing down due to insufficient braking force of the entire vehicle.It can be surely prevented.
[0083]
Further, according to the first and second embodiments described above, when the master cylinder pressure Pm becomes equal to or higher than the reference value Pmo, the target braking pressure Ptf of the front wheels is gradually increased as the master cylinder pressure Pm increases, thereby As the amount of braking operation increases, the amount of braking force applied to the front wheels gradually increases. For example, compared to when the amount of braking force applied to the front wheels is constant, the amount of braking force applied to the front wheels is started. Abrupt changes in braking force can be reliably prevented, and the distribution of braking force is gradually distributed as the amount of braking operation by the driver increases and the possibility that the rear wheels will be locked before the front wheels increases. It can be controlled closer to the front wheels.
[0084]
Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.
[0085]
For example, in each of the illustrated embodiments, the reference value Pmo for determining whether or not to start applying the braking force of the front wheels is smaller as the vehicle speed V is higher and the lateral acceleration Gy of the vehicle is larger. The smaller the speed Gxb is, the larger the calculation is. However, any of the vehicle speed V, the lateral acceleration Gy of the vehicle, and the deceleration Gxb of the vehicle may be omitted, and the reference value Pmo is set to a constant value. May be modified.
[0086]
  In the illustrated embodiments, the coefficient K that determines the amount of braking force applied to the front wheels increases as the vehicle speed V increases.bigIn addition, the vehicle speed V, the vehicle lateral acceleration Gy, and the vehicle acceleration Vy are set to be larger as the vehicle deceleration Gxb is smaller and larger as the vehicle lateral acceleration Gy is larger. Any of the vehicle deceleration Gxb may be omitted, and the coefficient K may be modified to be set to a constant value.
[0087]
In each of the illustrated embodiments, when the master cylinder pressure Pm exceeds the reference value Pmo, the target braking pressure Ptf for the front wheels is increased K times the master cylinder pressure Pm, so that the master cylinder pressure Pm As the master cylinder pressure Pm increases, for example, as the master cylinder pressure Pm increases, the additional amount of the braking force of the front wheels increases so that the braking force of the front wheels increases linearly. Thus, the braking force of the front wheels may be corrected so as to increase nonlinearly, and when the master cylinder pressure Pm is higher than the holding pressure Pc of the rear wheels, the braking force of the front wheels is increased even if the master cylinder pressure Pm increases. It may be modified so as not to increase.
[0088]
Further, in each of the illustrated embodiments, in the region where the master cylinder pressure Pm is greater than or equal to the reference value Pmo, the master cylinder pressure Pm, that is, the driver, is greater than the region where the master cylinder pressure Pm is less than the reference value Pmo. Since the ratio of the braking force of the entire vehicle to the amount of braking operation increases, for example, the ratio of the increase in the master cylinder pressure Pm to the pedal stroke becomes small in the region where the master cylinder pressure Pm is greater than or equal to the reference value Pmo. A brake pedal may be employed, so that the ratio of the braking force of the entire vehicle to the pedal stroke is constant regardless of the amount of braking operation by the driver, and the feeling during braking may be further improved.
[0089]
In the illustrated embodiments, the target braking pressure Ptr for the rear wheels is calculated based only on the master cylinder pressure Pm. For example, the larger the lateral acceleration Gy of the vehicle, In other words, it may be corrected so as to be calculated based on the master cylinder pressure Pm and the lateral acceleration Gy of the vehicle so that the vehicle is likely to become unstable.
[0090]
In each of the illustrated embodiments, the rear wheel holding pressure Pc is a predetermined constant. For example, the vehicle speed Vc increases so that the vehicle speed V increases and the vehicle deceleration Vxb decreases. Or you may correct | amend so that it may variably set according to the deceleration Gxb of a vehicle.
[0091]
In the illustrated embodiments, the braking pressure of the rear wheels is maintained at a constant value of the holding pressure Pc during the front-rear wheel distribution control of the braking force. The rear wheel holding pressure Pc may be gradually decreased or gradually increased in accordance with the slip state, so that the rear wheel braking pressure may be gradually decreased or gradually increased by pulse increase.
[0092]
In each of the above-described embodiments, the left and right front wheels and the left and right rear wheels are controlled to the same pressure while the front wheel braking force is being applied and during the front and rear wheel distribution control of the braking force. For example, the braking pressure of the left and right front wheels or the braking pressure of the left and right rear wheels may be corrected to be different from each other according to the turning situation of the vehicle and the behavior of the vehicle.
[0093]
Further, in each of the above-described embodiments, the left and right front wheels and the left and right rear wheels form one system, and the braking pressure of each system is controlled mainly by the communication control valves 22F and 22R. The braking device to which the control device is applied can control the braking pressure of the front wheels to a value higher than the master cylinder pressure, and can control the braking pressure of the rear wheels to a value lower than the master cylinder pressure. As long as it is an arbitrary configuration known in the art.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electronic control device of a first embodiment of a braking control device according to the present invention.
FIG. 2 is an illustrative sectional view showing a front wheel communication control valve shown in FIG. 1;
FIG. 3 is a flowchart showing a braking force distribution control routine for front and rear wheels in the first embodiment.
FIG. 4 is a graph showing a relationship between a master cylinder pressure Pm, a front wheel target braking pressure Ptf, and a rear wheel target braking pressure Ptr in the first embodiment.
FIG. 5 is a graph showing a relationship between a vehicle speed V and a braking effectiveness coefficient BEF.
FIG. 6 is a graph showing a relationship between a master cylinder pressure Pm, a front target final brake pressure Pttf, and a rear target final brake pressure Pttr in the first embodiment.
FIG. 7 is a graph showing the relationship (solid line) between the ideal front / rear distribution line and the front wheel braking pressure Pf and the rear wheel braking pressure Pr in the first embodiment in comparison with the case of the prior art (broken line). is there.
FIG. 8 is a flowchart showing a braking force distribution control routine for front and rear wheels in the second embodiment.
FIG. 9 is a graph showing the relationship between a master cylinder pressure Pm, a final target braking pressure Pttf for the front wheels, and a final target braking pressure Pttr for the rear wheels in the second embodiment.
[Explanation of symbols]
10 ... Brake device
14 ... Master cylinder
22F, 22R ... Communication control valve
26FL, 26FR, 26RL, 26RR ... Wheel cylinder
42F, 42R ... Oil pump
28FL-28RR, 34FL-34RR ... Open / close valve
42F, 42R ... Pump
60F, 60R ... Suction control valve
70 ... Valve
74 ... Valve element
84 ... Compression coil spring
88 ... Check valve
90 ... Electronic control unit
96 ... Pressure sensor
98 ... Vehicle speed sensor
100: longitudinal acceleration sensor
102 ... Lateral acceleration sensor

Claims (9)

マスタシリンダの作動液圧を各車輪に対応して設けられた制動力発生装置のホイールシリンダへ供給することにより制動力を発生し、車輌の運転状態が所定の状態になると後輪の制動力の上昇を抑制する前後輪制動力配分制御を行う車輌の制動制御装置にして、運転者の制動操作量について見て前記前後輪制動力配分制御が行われる領域以下の領域に於いて前輪の制動力を運転者の制動操作量に対応する制動力よりも高くする前輪制動力付加手段を有し、前記前輪制動力付加手段は運転者の制動操作量が基準値以上であるときに前輪の制動力を運転者の制動操作量に対応する制動力よりも高くし、前記基準値を車輌の状態に応じて変更することを特徴とする車輌の制動制御装置。A braking force is generated by supplying the hydraulic pressure of the master cylinder to a wheel cylinder of a braking force generator provided corresponding to each wheel, and when the driving state of the vehicle reaches a predetermined state, the braking force of the rear wheel is reduced. In a vehicle braking control device that performs front / rear wheel braking force distribution control that suppresses the increase, the braking force of the front wheels is determined in a region below the region where the front / rear wheel braking force distribution control is performed in view of the amount of braking operation performed by the driver. have a front wheel braking force applying means to be higher than the braking force corresponding to the braking operation by a driver and the front wheel braking force when the said front wheel braking force adding means braking operation by a driver is equal to or larger than the reference value Is made higher than the braking force corresponding to the braking operation amount of the driver, and the reference value is changed according to the state of the vehicle. 前記前輪制動力付加手段は前輪の制動力を高くする量を車輌の状態に応じて変更することを特徴とする請求項１に記載の車輌の制動制御装置。  2. The vehicle braking control device according to claim 1, wherein the front wheel braking force adding means changes an amount of increasing the braking force of the front wheel in accordance with the state of the vehicle. 前記前輪制動力付加手段は車速が高いほど前輪の制動力を高くする量が大きくなるよう車速に応じて前輪の制動力を高くする量を可変設定することを特徴とする請求項２に記載の車輌の制動制御装置。The said front wheel braking force addition means variably sets the amount which raises the braking force of a front wheel according to a vehicle speed so that the amount which makes the braking force of a front wheel high becomes large, so that a vehicle speed is high. A braking control device for a vehicle. 前記前輪制動力付加手段は車輌の減速度が低いほど前輪の制動力を高くする量が大きくなるよう車輌の減速度に応じて前輪の制動力を高くする量を可変設定することを特徴とする請求項２又は３に記載の車輌の制動制御装置。The front wheel braking force adding means variably sets the amount of increasing the braking force of the front wheels according to the deceleration of the vehicle so that the amount of increasing the braking force of the front wheels increases as the deceleration of the vehicle decreases. The vehicle braking control device according to claim 2 or 3. 前記前輪制動力付加手段は車輌の横加速度の大きさが大きいほど前輪の制動力を高くする量が大きくなるよう車輌の横加速度に応じて前輪の制動力を高くする量を可変設定することを特徴とする請求項２乃至４の何れかに記載の車輌の制動制御装置。The front wheel braking force adding means variably sets the amount of increasing the braking force of the front wheels according to the lateral acceleration of the vehicle so that the amount of increasing the braking force of the front wheels increases as the lateral acceleration of the vehicle increases. The vehicle braking control device according to any one of claims 2 to 4, 前記前輪制動力付加手段は運転者の制動操作量が高くなるにつれて前輪の制動力を高くする量を大きくすることを特徴とする請求項１乃至５の何れかに記載の車輌の制動制御装置。Vehicle brake control device according to any one of claims 1 to 5 wherein the front wheel braking force applying means, characterized in that to increase the amount of higher braking force of the front wheel as the brake operation amount of the driver is high. 前記前輪制動力付加手段は車速が高いほど前記基準値が小さくなるよう車速に応じて前記基準値を可変設定することを特徴とする請求項１乃至６の何れかに記載の車輌の制動制御装置。7. The vehicle braking control device according to claim 1, wherein the front wheel braking force adding means variably sets the reference value according to the vehicle speed so that the reference value decreases as the vehicle speed increases. . 前記前輪制動力付加手段は車輌の減速度が低いほど前記基準値が大きくなるよう車輌の減速度に応じて前記基準値を可変設定することを特徴とする請求項１乃至７の何れかに記載の車輌の制動制御装置。The said front wheel braking force addition means variably sets the said reference value according to the deceleration of a vehicle so that the said reference value becomes large, so that the deceleration of a vehicle is low. Vehicle brake control device. 前記前輪制動力付加手段は車輌の横加速度の大きさが大きいほど前記基準値が小さくなるよう車輌の横加速度に応じて前記基準値を可変設定することを特徴とする請求項１乃至８の何れかに記載の車輌の制動制御装置。9. The front wheel braking force adding means variably sets the reference value according to the lateral acceleration of the vehicle so that the reference value decreases as the lateral acceleration of the vehicle increases. A vehicle braking control device according to claim 1.
JP2001360517A 2001-11-27 2001-11-27 Brake control device for vehicle Expired - Fee Related JP3829926B2 (en)

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