JP4134682B2 - Slip detection device for power transmission mechanism - Google Patents

Description

【００４２】
上記ステップＳ２についで、ベルト式無段変速機４に入力されるトルクの向きが、逆入力である場合に、ベルト２８の滑りを想定したときのしきい値kslp１（ｉ）を算出する（ステップＳ３）。このステップＳ３についで、前記相関係数ｋ（ｉ）が、しきい値kslp１（ｉ）以下であるか否かが判断される（ステップＳ４）。このステップＳ４で否定的に判断された場合は、リターンされる。これに対して、ステップＳ４で肯定判断された場合は、「ベルト式無段変速機４に対するトルクの入力の向きがいずれであるかを判別する制御」が実施されているか否かが判断される（ステップＳ５）。
【００４３】
このステップＳ５で否定的に判断された場合は、「ベルト式無段変速機４に対するトルクの入力の向きがいずれであるかを判別する制御」を実行し（ステップＳ６）、ステップＳ７に進む。なお、ステップＳ６の処理例は後述する。これに対して、ステップＳ５で肯定判断された場合は、そのままステップＳ７に進む。
【００４４】
このステップＳ７では、「ベルト式無段変速機４に対するトルクの入力の向きがいずれであるかを判別する制御」の結果に基づき、逆入力による滑りか否かが判断される（ステップＳ７）。このステップＳ７で肯定的に判断された場合は、“ベルト２８の滑り量が、しきい値以下である。”と判定する（ステップＳ８）。このステップＳ８についで、ベルト２８の滑り量を減少させる制御を実行し（ステップＳ９）、リターンする。このステップＳ９では、例えば、ベルト２８に加えられる挟圧力を高める制御が実行される。
【００４５】
前記ステップＳ７で否定的に判断された場合は、正入力によるベルト２８の滑りを想定したときのしきい値kslp２（ｉ）を算出する（ステップＳ１０）。このステップＳ１０についで、前記相関係数ｋ（ｉ）が、しきい値kslp２（ｉ）以下であるか否かが判断される（ステップＳ１１）。このステップＳ１１で肯定判断された場合はステップＳ８に進み、ステップＳ１１で否定的に判断された場合は、リターンされる。
【００４６】
上記の制御において、前記しきい値kslp１（ｉ）およびしきい値kslp２（ｉ）は、各種のパラメータ基づいて設定することができる。前記各種のパラメータとしては、例えば、車速、ベルト式無段変速機４の変速比、ベルト式無段変速機４の実際の変速速度、車両の加減速度、変速指令値などが挙げられる。また、しきい値kslp１（ｉ）としきい値kslp２（ｉ）とは大小関係が異なる。具体的には、しきい値kslp１（ｉ）の方が、しきい値kslp２（ｉ）よりも大きく設定される。その理由は、正入力によるベルト２８の滑りが、“急激なダウンシフトに起因するベルト２８の滑りである。”と誤判定されることを回避するためである。
【００４７】
つぎに、図１のステップＳ６の第１の処理例を、図３のフローチャートに基づいて説明する。まず、相関係数ｋ（ｉ）の算出に用いたセカンダリシャフト５５の回転速度Ｎout （ｉ）よりも、ｎ回前に計測されたセカンダリシャフト５５の回転速度Ｎout （ｉ−ｎ）と、このセカンダリシャフト５５の回転速度Ｎout （ｉ−ｎ）よりも１回前に計測されたセカンダリシャフト５５の回転速度Ｎout （ｉ−ｎ−１）とに基づいて、セカンダリシャフト５５の回転速度の時間変化量ΔＮout （ｉ）を算出する（ステップＳ２１）。
【００４８】
このステップＳ２１についで、車両Ｖｅの運転条件に応じたしきい値ΔＮout slp を算出する（ステップＳ２２）。上記車両Ｖｅの運転条件としては、例えば、車速、ベルト式無段変速機４の変速比、ベルト式無段変速機４の実際の変速速度、車両の加減速度、変速指令値などが挙げられる。そして、セカンダリシャフト５５の回転速度の時間変化量ΔＮout （ｉ）が、しきい値ΔＮout slp 以下であるか否かが判断される（ステップＳ２３）。このステップＳ２３で肯定的に判断された場合は、逆入力による滑りと判定され、図１のステップＳ７に進む。これに対して、ステップＳ２３で否定的に判断された場合は。正入力による滑りであると判定され、図１のステップＳ７に進む。
【００４９】
このように、図３のフローチャートでは、セカンダリシャフト５５の回転速度の時間変化量ΔＮout に基づいて、逆入力であるか否かを判断している。その理由は、逆入力によりベルト２８の滑りが発生する場合は、セカンダリシャフト５５の回転速度Ｎout が急激に低下して、そのセカンダリシャフト５５の回転速度の時間変化量ΔＮout が、車両の減速時（アクセル開度の全閉時など）におけるセカンダリシャフト５５の回転速度の時間変化量ΔＮout よりも、非常に小さい値となるからである。
【００５０】
つぎに、図３のフローチャートに対応するタイムチャートの一例を、図４および図５に示す。図４および図５のタイムチャートでは、相関係数ｋ（ｉ）の時間変化が示され、出力軸回転数の時間変化が示され、出力軸回転加速度の時間変化が示されている。なお、しきい値の変化量Δkslp１およびしきい値の変化量Δkslp２は、便宜上、略一定に示されている。まず、正入力に相当する図４のタイムチャートについて説明する。時刻ｔ１以前においては、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp１を越えており、時刻ｔ１で、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp１以下となっている。つまり、時刻ｔ１において、図１のステップＳ３で肯定判断される。
【００５１】
一方、時刻ｔ１以前および時刻ｔ１以後のいずれにおいても、出力軸回転加速度、すなわち、セカンダリシャフト５５の回転速度の時間変化量ΔＮout （ｉ）は、しきい値ΔＮout slp を越えている。つまり、時刻ｔ１において、図１のステップＳ４で肯定判断され、かつ、図３のステップＳ２５に進むことを意味する。ついで、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp２以下になる時刻ｔ２において、図１のステップＳ１１で肯定判断される。
【００５２】
さらに、逆入力に相当する図５のタイムチャートについて説明する。時刻ｔ１以前では、セカンダリシャフト５５の回転速度の時間変化量ΔＮout （ｉ）は、しきい値ΔＮout slp を越えている。時刻ｔ１以後は、セカンダリシャフト５５の回転速度の時間変化量ΔＮout （ｉ−ｎ）が、しきい値ΔＮout slp 未満となっている。すなわち、図３のフローチャートでステップＳ２４に進む。さらに、時刻ｔ２において、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp１以下となり、図１のステップＳ１１で肯定判断される。
【００５３】
さらに、図１のステップＳ６の第２の処理例を、図６のフローチャートに基づいて説明する。まず、ベルト２８の滑りが発生する直前における、ベルト式無段変速機４の変速比γ preを算出する（ステップＳ３１）。ここで、
γ pre＝γ（ｉ−ｍ）
として算出する。なお、上記数式において“ｉ−ｍ”はベルト２８の滑りが発生する直前を意味している。
【００５４】
このステップＳ３１についで、ベルト式無段変速機４の変速比γ preと、プライマリシャフト５１の回転速度Ｎin（ｉ）と、セカンダリシャフト５５の回転速度Ｎout （ｉ）とに基づいて、ベルト２８の相対滑り速度Ｎslp を算出する（ステップＳ３２）。
【００５５】
具体的には、
ベルト２８の相対滑り速度Ｎslp ＝Ｎin（ｉ）／γ pre−Ｎout （ｉ）
として算出される。
【００５６】
前記ステップＳ３２についで、車両Ｖｅの運転条件に応じたしきい値Ｎslp max が算出される（ステップＳ３３）。上記車両Ｖｅの運転条件としては、例えば、車速、ベルト式無段変速機４の変速比、ベルト式無段変速機４の実際の変速速度、車両の加減速度、変速指令値などが挙げられる。さらに、ステップＳ３３についで、ベルト２８の相対滑り速度Ｎslp が、しきい値Ｎslp max 以下であるか否かが判断される（ステップＳ３４）。このステップＳ３４で肯定的に判断された場合は、ステップＳ２４を経由して、図１のステップＳ７に進む。これに対して、ステップＳ３４で否定的に判断された場合は、ステップＳ２５を経由して、図１のステップＳ７に進む。図６のステップＳ２４の処理は、図３のステップＳ２４の処理と同じであり、図６のステップＳ２５の処理は、図３のステップＳ２５の処理と同じである。
【００５７】
以上のように、図６のフローチャートにおいては、プライマリプーリ２４およびセカンダリプーリ２５に対するベルト２８の掛かり径に基づいてベルト式無段変速機４の変速比を算出し、ベルト式無段変速機４の変速比と、プライマリシャフト５１の回転速度Ｎinおよびセカンダリシャフト５５の回転速度Ｎout とに基づいて、逆入力であるか否かを判断している。このように、図６のフローチャートにおいては、ベルトの滑りが発生する直前における変速比（プーリに対するベルトの巻き掛かり径）に基づいて相対滑り速度を算出し、その相対滑り速度に基づいて、正入力または逆入力を判別する処理がおこなわれる。
【００５８】
つぎに、図６のフローチャートに対応するタイムチャートの一例を、図７および図８に示す。図７および図８のタイムチャートでは、相関係数ｋ（ｉ）の時間変化が示され、ベルト式無段変速機４の変速比の時間変化が示され、出力回速度の時間変化および入力回転速度の時間変化が示されている。なお、図７，図８のタイムチャートでは、しきい値の変化量Δkslp１およびしきい値の変化量Δkslp２は、便宜上、略一定に示されている。また、ベルトに滑りが発生していない状態では、変速比に関わりなく入力回転速度と出力回転速度とを同じ回転速度として示すために、入力回転速度として、Ｎin（ｉ）／γ preを用いている。
【００５９】
まず、正入力に相当する図７のタイムチャートについて説明する。時刻ｔ１以前においては、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp１を越えているとともに、入力回転速度（破線）と出力回転速度（実線）とが一致している。そして、時刻ｔ１において、変速比が大きくなり始めるとともに、入力回転速度と出力回転速度とに差が生じている。具体的には、入力回転速度の方が出力回転速度よりも高速となっている。
【００６０】
このように、時刻ｔ１でベルトの滑りが開始されると、ベルトが滑る直前におけるベルト式無段変速機の変速比が算出される。さらに、時刻ｔ２において、変速比が小さくなり始めるとともに、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp１以下となり、その後、時刻ｔ３において、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp２以下となっている。すなわち、図１のステップＳ１１で肯定判断される。
【００６１】
つぎに、逆入力に相当する図８のタイムチャートについて説明する。時刻ｔ１以前においては、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp１を越えているとともに、入力回転速度と出力回転速度とが一致している。そして、時刻ｔ１において、変速比が大きくなり始めるとともに、入力回転速度と出力回転速度とに差が生じている。具体的には、入力回転速度よりも出力回転速度の方が高速となっている。
【００６２】
このように、時刻ｔ１でベルトの滑りが開始されると、ベルトが滑る直前におけるベルト式無段変速機の変速比が算出される。さらに、時刻ｔ２において、変速比が小さくなり始めるとともに、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp１以下となり、逆入力による滑りと判定される。その後、相関係数ｋ（ｉ）が、しきい値の変化量Δkslp１よりも大きくなっている。なお、図４、図５、図７、図８において、異なる図に示されている時刻同士には対応関係はない。
【００６３】
このように、図１の制御例によれば、同じ相関係数ｋ（ｉ）と、ベルト２８の滑り判定に用いるしきい値kslpとの対応関係に基づいて、ベルト２８の滑り状態を検出する場合に、ベルト式無段変速機４に入力されるトルクの向きが、正方向であるか逆方向であるかを判断し、その判断結果に基づいて、しきい値kslpを設定している。したがって、ベルト式無段変速機４のベルト２８の滑り検出精度を向上することができる。また、セカンダリシャフト５５の回転速度の時間変化量に基づいて、逆入力であるか否かを判断しているため、ベルト式無段変速機４に入力されるトルクの向きを高精度に検出できる。
【００６４】
なお、図１の制御例は、相関係数ｋ（ｉ）と比較するしきい値を、逆入力か否かにより変更する制御例であるが、ベルト２８の滑りの有無を判断するしきい値、または、ベルト２８の滑りの程度（滑り量、滑り速度、滑りの発生回数など）を判断するしきい値を、逆入力か否かにより変更する制御も、各請求項の発明に含まれる。
【００６５】
ここで、図１、図３、図６に示された機能的手段と、この発明の構成との対応関係を説明すれば、図１に示されたステップＳ１ないしステップＳ８、ステップＳ１０およびステップＳ１１、図３に示されたステップＳ２１ないしステップＳ２５、図６に示されたステップＳ３１ないしステップＳ３４、ステップＳ２４、ステップＳ２５が、この発明の滑り判断手段に相当する。また、ベルト２８の滑りの有無や、ベルト２８の滑りの程度、ベルト２８の相対滑り速度などが、この発明の第１の回転部材と第２の回転部材との間で発生する滑り状態に相当し、相関係数ｋ（ｉ）が、この発明の“第１回転部材と第２の回転部材とに基づく物理量”に相当し、しきい値kslpが、この発明の基準値に相当し、しきい値kslp１（ｉ）が、この発明の“第２の回転部材から第１の回転部材にトルクが伝達される場合に選択する基準値”に相当し、しきい値kslp２（ｉ）が、この発明の“第１の回転部材から第２の回転部材にトルクが伝達される場合に選択する基準値”に相当し、しきい値ΔＮout slpが、この発明の所定量に相当する。
【００６６】
また、図２に示された構成と、この発明の構成との対応関係を説明すれば、プライマリシャフト５１およびプライマリプーリ２４が、この発明の第１の回転部材に相当し、セカンダリプーリ２５およびセカンダリシャフト５５が、この発明の第２の回転部材に相当し、ベルト式無段変速機４が、この発明の動力伝達機構に相当し、エンジンおよび電動機が、この発明の駆動力源に相当する。
【００６７】
なお、図１のパワートレーンでは、変速比を連続的に制御することのできる無段変速機として、ベルト式無段変速機４が用いられているが、他の無段変速機、例えば、トロイダル式無段変速機を有する車両に対しても、この発明を適用可能である。トロイダル式無段変速機は、トロイダル面を有する入力ディスクおよび出力ディスクと、各ディスクに対して接触するパワーローラとを有する変速機である。各ディスクとパワーローラとの接触面には潤滑油が存在する。そして、パワーローラを、各ディスクの軸線に直交する平面内で直線状に移動させて、パワーローラと各ディスクとの接触半径を調整することにより、入力ディスクと出力ディスクとの間の変速比が制御される。また、各ディスクとパワーローラとの接触面圧を調整することにより、入力ディスクと出力ディスクとの間で伝達されるトルクの容量が制御される。
【００６８】
すなわち、各ディスクとパワーローラとの接触面圧を高圧にすると、潤滑油がガラス状になり、いわゆるトラクション伝動（せん断力）により、入力ディスクと出力ディスクとの間で動力の伝達がおこなわれる。このように、各ディスクとパワーローラとの接触面圧を調整するための油圧サーボ機構が設けられている。油圧サーボ機構は、ピストンと、各ピストンを動作させる第１の油圧室とを有している。また、パワーローラを各ディスクの軸線に直交する平面内で直線状に移動させる油圧サーボ機構が設けられている。この油圧サーボ機構は、第２の油圧室を有している。このトロイダル式無段変速機においては、駆動力源のトルクが、入力ディスクからパワーローラを経由して出力ディスクに伝達される正入力と、車輪の運動エネルギによるトルクは、出力ディスクからパワーローラを経由して入力ディスクに伝達される逆入力とが発生する。このトロイダル式無段変速機におけるトルク容量は、第１の油圧室の油圧に応じて、各ディスクに加えられる軸線方向の挟圧力により制御される。
【００６９】
このようなトロイダル式無段変速機に対して、請求項１ないし７の発明を適用することができる。この場合、入力ディスクがこの発明の第１の回転部材に相当し、出力ディスクがこの発明の第２の回転部材に相当し、パワーローラの滑り状態が、この発明の“第１の回転部材と第２の回転部材との間で生じる滑り状態”に相当する。そして、そのパワーローラの滑り状態の検出に用いるしきい値が、トロイダル式無段変速機に対するトルクの入力方向に応じて変更される。
【００７０】
さらに、駆動力源と車輪との間に、摩擦式のクラッチなどの動力伝達機構が設けられている車両に対しても、請求項１ないし７の発明を適用することができる。摩擦式のクラッチの配置位置は、駆動力源と変速機との間の動力伝達経路、または、変速機と車輪との間の動力伝達経路、または有段変速機の一部のいずれであってもよい。この摩擦式のクラッチは、例えば、第１の回転部材に設けられた摩擦材と、第２の回転部材に設けられた摩擦材とにより構成される。そして、油圧制御装置（図示せず）などにより、クラッチの係合圧が制御される。
【００７１】
さらに、駆動力源のトルクが第１の回転部材を経由して第２の回転部材に伝達される正入力と、車輪の運動エネルギに相当するトルクが、第２の回転部材を経由して第１の回転部材に伝達される逆入力とが生じる。このクラッチを有する車両においては、摩擦材同士の間で生じる滑り状態が、この発明の滑り状態に相当する。そして、クラッチの滑り状態の検出に用いるしきい値が、クラッチに対するトルクの入力方向に応じて変更される。
【００７２】
以上のように、この発明は、第１の回転部材と第２の回転部材とが、介在物（例えば、ベルト、パワーローラ、潤滑油）を介して、間接的に動力伝達可能に連結される構成の第１の動力伝達機構（例えば、ベルト式無段変速機、トロイダル式無段変速機）、または、第１の回転部材と第２の回転部材とが直接接触する構成の第２の動力伝達機構（摩擦式クラッチ）のいずれにも適用可能である。
【００７３】
そして、
▲１▼第１の動力伝達機構においては、第１の回転部材または第２の回転部材と、介在物との接触部分における滑り状態が検出される。
なお、
▲２▼トロイダル式無段変速機においては、パワーローラおよび潤滑油を、共に介在物であると把握することができ、この場合は、介在物同士の接触部分（境界面）における滑り状態を検出することもできる。
【００７４】
これに対して、
▲３▼第２の動力伝達機構においては、第１の回転部材と第２の回転部材との接触部分における滑り状態が検出される。
【００７５】
したがって、請求項１ないし７の発明において、“第１の回転部材と第２の回転部材との間で生じる滑り状態”には、上記▲１▼なし▲３▼で述べた滑り状態が含まれる。
【００７６】
ここで、この実施例に開示された特徴的な構成を記載すれば、以下のとおりである。すなわち、第１の回転部材と第２の回転部材との間でトルクが伝達される場合に、前記第１の回転部材と第２の回転部材との間における滑り状態を検出する変速機の滑り検出装置において、前記第１の回転部材から前記第２の回転部材にトルクが伝達される場合と、前記第２の回転部材から前記第１の回転部材にトルクが伝達される場合とで、前記第１の回転部材と第２の回転部材との間で発生する滑り状態を検出する基準値を変更する滑り判断手段を備えていることを特徴とする変速機の滑り検出装置である。
【００７７】
ところで、この明細書の「特許請求の範囲」の各請求項に記載されている「滑り判断手段」を、「滑り判断器」または「滑り判断コントローラ」と読み替えることもできる。この場合、実施例で説明した電子制御装置３４が、「滑り判断器」および「滑り判断コントローラ」に相当する。また、各請求項に記載されている「動力伝達機構」を「作動機」または「バリエータ」と読み替えることもできる。さらにまた、各請求項に記載されている「滑り判断手段」を、「滑り判断ステップ」と読み替え、「動力伝達機構の滑り検出装置」を、「動力伝達機構の滑り検出方法」と読み替えることもできる。
【００７８】
【発明の効果】
以上説明したように、請求項１の発明によれば、第１の回転部材と第２の回転部材とに基づいて求めた相関係数と、基準値とを比較して滑り状態を検出する場合に、相関係数が基準値以下である場合に、第１の回転部材と第２の回転部材との間における相対滑り速度が、所定量以上であると判定する。また、動力伝達機構に入力されるトルクの向きに基づいて、基準値の大小を設定するため、動力伝達機構の滑り状態の検出精度が向上する。
【００８１】
請求項２の発明によれば、請求項１の発明と同様の効果を得ることができる他に、駆動力源のトルクが、第１の回転部材を経由して第２の回転部材に伝達される場合と、車輪のトルクが、第２の回転部材を経由して第１の回転部材に伝達される場合とで基準値を変更でき、滑り状態の検出精度が一層向上する。
【００８２】
請求項３の発明によれば、請求項２の発明と同様の効果を得ることができる他に、駆動力源のトルクが第１の回転部材から第２の回転部材に伝達される場合の滑りと、車輪のトルクが第２の回転部材から第１の回転部材に伝達される場合の滑りとを、第２の回転部材の回転速度の時間変化量に基づいて識別することができる。
【００８３】
請求項４の発明によれば、請求項３の発明と同様の効果を得ることができる他に、第２の回転部材の回転速度の時間変化量が所定量以下の場合は、車輪のトルクが第２の回転部材から第１の回転部材に伝達される場合の滑りであると判断する。これに対して、第２の回転部材の回転速度の時間変化量が、所定量を越えている場合は、駆動力源のトルクが第１の回転部材から第２の回転部材に伝達される場合の滑りであると判断する。したがって、滑りの検出精度を一層向上することができる。
【００８４】
請求項５の発明によれば、請求項１ないし４のいずれかの発明と同様の効果を得ることができる他に、ベルト式無段変速機のベルトの滑り検出精度を向上することができる。
【図面の簡単な説明】
【図１】 この発明の動力伝達機構の検出装置の一例を示すフローチャートである。
【図２】 この発明の動力伝達機構の検出装置を適用可能な車両のパワートレーンおよびその制御系統を示す概念図である。
【図３】 図１に示すフローチャートの処理の一部の具体例を示すフローチャートである。
【図４】 図１および図３に示すフローチャートに対応するタイムチャートの一例である。
【図５】 図１および図３に示すフローチャートに対応するタイムチャートの一例である。
【図６】 図１に示すフローチャートの処理の一部の具体例を示すフローチャートである。
【図７】 図１および図６に示すフローチャートに対応するタイムチャートの一例である。
【図８】 図１および図６に示すフローチャートに対応するタイムチャートの一例である。
【符号の説明】
１…エンジン（駆動力源）、 ２…車輪、 ４…ベルト式無段変速機、 ２４…プライマリプーリ、 ２５…セカンダリプーリ、 ２８…ベルト、 ３４…電子制御装置、 ５１…プライマリシャフト、 ５５…セカンダリシャフト、 Ｖｅ…車両。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power transmission mechanism that transmits torque between a first rotating member and a second rotating member, and for detecting a slipping state between the first rotating member and the second rotating member. It relates to the device.
[0002]
[Prior art]
As this type of power transmission mechanism, a torque is transmitted between the first rotating member and the second rotating member using a power transmission mechanism that transmits torque using frictional force and a shearing force of oil. A power transmission mechanism for transmission is known. In these power transmission mechanisms, torque is transmitted without depending on the meshing force. Therefore, when torque exceeding the torque capacity of the power transmission mechanism is input to the first rotating member or the second rotating member, Slip may occur between the first rotating member and the second rotating member. When such slipping occurs, there arises a problem that the power transmission efficiency of the power transmission mechanism is lowered and a problem that the durability of the parts constituting the power transmission mechanism is impaired. For example, in a belt type continuously variable transmission, wear of a belt and a pulley occurs, and in a toroidal type continuously variable transmission, wear of a power roller and a disk occurs.
[0003]
On the other hand, conventionally, a detection device capable of performing control corresponding to the slip of the power transmission mechanism is known, and an example of the detection device is disclosed in Japanese Patent Laid-Open No. 4-285361 (Patent Document 1). Are listed. In the vehicle described in this publication, engine torque is transmitted to drive wheels via a torque converter with a lock-up clutch, a forward / reverse switching device, a belt-type continuously variable transmission, a reduction gear device, and a differential gear device. It is configured as follows. The belt type continuously variable transmission includes an input shaft and an output shaft, variable pulleys respectively provided on the input shaft and the output shaft, and a belt wound around these variable pulleys.
[0004]
Further, the operation of the variable pulley is controlled by the hydraulic actuator, the belt winding diameter is adjusted, the gear ratio of the belt-type continuously variable transmission is controlled, and the clamping pressure on the belt is adjusted. Specifically, when the change width of the rotational acceleration of the drive wheel exceeds a predetermined criterion, the belt clamping pressure is temporarily increased. By such control, slipping and gripping of the driving wheels are repeated, and slipping of the belt is suppressed during a rough road traveling where a relatively large torque is transmitted from the driving wheel to the belt.
[0005]
[Patent Document 1]
JP-A-4-285361 (paragraph number 0004, paragraph number 0008, paragraph number 0011, paragraph number 0031, FIGS. 1 and 7)
[0006]
[Problems to be solved by the invention]
By the way, as described in the above publication, the case where the belt slips is caused by the case where the torque of the driving wheel is transmitted to the belt type continuously variable transmission and the belt slips (first case). In addition, the case where the engine torque is transmitted to the belt-type continuously variable transmission and the belt slips is considered (second case). However, in the above publication, there is no description about the second case, and how is the belt slip of the belt-type continuously variable transmission under the condition that both the first case and the second case occur? It is unclear whether it should be detected, and there is a possibility that the belt slip detection accuracy is lowered.
[0007]
The present invention has been made against the background of the above circumstances, and the detection accuracy of the slipping state can be improved regardless of whether the torque is input from the first rotating member or the second rotating member to the power transmission mechanism. An object of the present invention is to provide a slip detection device for a power transmission mechanism that can be improved.
[0008]
[Means for Solving the Problem and Action]
  In order to achieve the above object, the invention according to claim 1 is directed to the first rotation member and the second rotation member when torque is transmitted between the first rotation member and the second rotation member. In the slip detection device of the power transmission mechanism that detects the slip state between,The slip determining means is configured to determine whether the slippage between the first rotating member and the second rotating member is based on a comparison result between a physical quantity based on the first rotating member and the second rotating member and the reference value. A function for detecting a slipping state in the case, a function for obtaining a correlation coefficient based on the first rotating member and the second rotating member as the physical quantity, and when the correlation coefficient is equal to or less than a reference value A function of determining that a relative slip speed between the first rotating member and the second rotating member is equal to or greater than a predetermined amount; and torque is transmitted from the first rotating member to the second rotating member. A function of setting a value to be selected as the reference value when the torque is transmitted from the second rotating member to the first rotating member to be smaller than a value to be selected as the reference value. HaveIt is characterized by this.
[0009]
  According to invention of Claim 1, 1st rotation partThe relative slip speed between the first rotating member and the second rotating member is equal to or greater than a predetermined amount when the correlation coefficient obtained based on the material and the second rotating member is equal to or less than a reference value. It is judged. The reference value selected when torque is transmitted from the first rotating member to the second rotating member is the reference value selected when torque is transmitted from the second rotating member to the first rotating member. Is set smaller.
[0014]
  ClaimThe invention of claim 2 is the invention of claim 1.In addition to the configuration, the torque of the driving force source of the vehicle is transmitted to the second rotating member via the first rotating member, and the torque of the wheel transmits the second rotating member to the second rotating member. The configuration is such that the first rotation member is transmitted via the first rotation member.
[0015]
  ClaimAccording to invention of Claim 2, of Claim 1In addition to the effects similar to those of the invention, when the torque of the driving force source of the vehicle is transmitted to the second rotating member via the first rotating member, or the torque of the wheel is the second rotating In any case of being transmitted to the first rotating member via the member, a slipping state is detected.
[0016]
  ClaimThe invention of claim 3 is the invention of claim 2.In addition to the configuration, the slip determining means may be a slip generated when the torque of the driving force source is transmitted from the first rotating member to the second rotating member, or the torque of the wheel is the second torque. And a function of determining whether or not the slip occurs when the rotation member is transmitted from the first rotation member to the first rotation member based on a temporal change amount of the rotation speed of the second rotation member. Is.
[0017]
  ClaimAccording to invention of Claim 3, of Claim 2In addition to the effects similar to the invention, when the torque of the driving force source is transmitted from the first rotating member to the second rotating member, or the torque of the wheel is transmitted from the second rotating member to the first rotating member. It is determined based on the amount of change over time in the rotational speed of the second rotating member whether the slip has occurred when transmitted to the rotating member.
[0018]
  ClaimThe invention of claim 4 is the invention of claim 3.Previous in addition to the configurationWriting slipThe disconnecting means is generated when the torque of the wheel is transmitted from the second rotating member to the first rotating member when the temporal change amount of the rotational speed of the second rotating member is equal to or less than a predetermined amount. When the function of determining the slip and the amount of time change of the rotation speed of the second rotating member exceed a predetermined amount, the torque of the driving force source is rotated from the first rotating member to the second rotation. And a function of determining that the slip is generated when transmitted to the member.
[0019]
  ClaimAccording to the invention of claim 4 of claim 3,In addition to the same effect as the invention, when the time change amount of the rotation speed of the second rotating member is not more than a predetermined amount, the torque of the wheel is transmitted from the second rotating member to the first rotating member. It is judged that this is a slip. On the other hand, when the time change amount of the rotation speed of the second rotating member exceeds a predetermined amount, the torque of the driving force source is transmitted from the first rotating member to the second rotating member. It is judged that this is a slip.
[0020]
  ClaimThe invention of claim 5 is the invention of claims 1 to 4.In addition to any of the configurations, a belt-type continuously variable transmission is provided in which an endless belt is wound around the first rotating member and the second rotating member, and the first rotating member and Torque is transmitted to and from the second rotating member via the belt.
[0021]
  ClaimAccording to invention of Claim 5, Claims 1 thru | or 4 ofIn addition to the effects similar to any of the inventions, the belt slip state of the belt type continuously variable transmission is detected.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described based on specific examples. FIG. 2 schematically shows an example of a power train and a control system of a vehicle Ve to which the detection device of the present invention can be applied. The power train shown here is configured such that the torque of the driving force source 1 is transmitted to a belt-type continuously variable transmission 4 as a power transmission mechanism via a torque converter 9 and a forward / reverse switching mechanism 8. Yes. As the driving force source 1, at least one of an engine or an electric motor can be used. As this engine, for example, an internal combustion engine, specifically, a gasoline engine, a diesel engine, an LPG engine, or the like can be used. Hereinafter, a case where a gasoline engine is used as the driving force source 1 will be described, and the driving force source 1 will be referred to as “engine 1” for convenience.
[0023]
The torque converter 9 connected to the output shaft of the engine 1 has the same structure as that of a torque converter employed in a conventional vehicle, and the pump impeller 11 is connected to the front cover 10 to which the output shaft of the engine 1 is connected. Are integrated, and a turbine runner 12 facing the pump impeller 11 is provided. The turbine runner 12 is connected to the shaft 50 so as to rotate integrally. . The pump impeller 11 and the turbine runner 12 are provided with a large number of blades (not shown), and power is transmitted between the pump impeller 11 and the turbine runner 12 by the kinetic energy of the fluid.
[0024]
In addition, a stator 13 that selectively changes the flow direction of the fluid sent from the turbine runner 12 and flows into the pump impeller 11 is disposed in the inner peripheral portion of the pump impeller 11 and the turbine runner 12. . The stator 13 is connected to a predetermined fixing portion 15 via a one-way clutch 14.
[0025]
The torque converter 9 includes a lockup clutch 16. The lockup clutch 16 is arranged in parallel with the power transmission path from the front cover 10 to the shaft 50. The lockup clutch 16 is attached so as to rotate integrally with the shaft 50, and the engagement / release of the lockup clutch 16 and the front cover 10 is controlled by the hydraulic control device 59.
[0026]
The forward / reverse switching mechanism 8 is a mechanism that is employed when the rotational direction of the engine 1 is limited to one direction, and switches the power transmission state between the shaft 50 and the primary shaft 51. is there. Specifically, a function of switching the rotation direction of the primary shaft 51 with respect to the rotation direction of the shaft 50 is provided.
[0027]
In the example shown in FIG. 2, a double pinion type planetary gear mechanism is employed as the forward / reverse switching mechanism 8. That is, a sun gear 17 that rotates integrally with the shaft 50 and a ring gear 18 that is arranged concentrically with the sun gear 17 are provided, and a pinion gear 19 that meshes with the sun gear 17 and a pinion gear between the sun gear 17 and the ring gear 18. 19 and another pinion gear 20 meshed with the ring gear 18 are arranged, and the pinion gears 19 and 20 are held by a carrier 21 so as to rotate and revolve freely.
[0028]
Further, a forward clutch 22 that connects the sun gear 17 and the shaft 50 and the carrier 21 so as to be integrally rotatable is provided. A reverse brake 23 that reverses the rotation direction of the primary shaft 51 with respect to the rotation direction of the shaft 50 by selectively fixing the ring gear 18 is provided. Engagement / release of the forward clutch 22 and the reverse brake 23 is controlled by a hydraulic control device 59. The primary shaft 51 and the carrier 21 are connected so as to rotate integrally.
[0029]
The belt type continuously variable transmission 4 includes a primary pulley 24 and a secondary pulley 25 that are arranged in parallel to each other. First, the primary pulley 24 is configured to rotate integrally with the primary shaft 51. The primary pulley 24 is a movable sheave that is operated in the axial direction of the primary shaft 51 by a fixed sheave 52 and a hydraulic actuator 26. 53.
[0030]
On the other hand, the secondary pulley 25 is configured to rotate integrally with the secondary shaft 55. The secondary pulley 25 is operated in the axial direction of the secondary shaft 55 by the fixed sheave 54 and the hydraulic actuator 27. Movable sheave 56. Further, an annular belt 28 is wound around the primary pulley 24 and the secondary pulley 25. Further, the actuators 26 and 27 are controlled by a hydraulic control device 59. The differential 6 is connected to the secondary shaft 55 via the gear transmission 29, and the wheel 2 is connected to the differential 6.
[0031]
Next, a control system for the vehicle Ve shown in FIG. 2 will be described. First, an electronic control unit (ECU) 34 is provided. The electronic control unit 34 is a microcomputer having an arithmetic processing unit (CPU or MPU), a storage unit (RAM and ROM), and an input / output interface. It is configured. The electronic control unit 34 includes a signal from the engine rotational speed sensor 30, a signal from the turbine rotational speed sensor 31 that detects the rotational speed of the shaft 50, a signal from the input rotational speed sensor 32 that detects the rotational speed of the primary shaft 51, a secondary A signal of the output rotation speed sensor 33 that detects the rotation speed of the shaft 55, a signal of the acceleration request detection sensor 57, a signal of the braking request detection sensor 58, a signal of the shift position sensor 60, and the like are input. The electronic control device 34 outputs a signal for controlling the engine 1, a signal for controlling the hydraulic control device 59, and the like.
[0032]
In the vehicle Ve configured as described above, the torque output from the engine 1 is transmitted to the forward / reverse switching mechanism 8 via the torque converter 9 or the lockup clutch 16. Torque output from the forward / reverse switching mechanism 8 is transmitted to the wheels 2 via the belt-type continuously variable transmission 4 and the gear transmission 29 to generate driving force. When the lockup clutch 16 is released during the torque transmission, power is transmitted between the pump impeller 11 and the turbine runner 12 by the kinetic energy of the fluid. On the other hand, when the lockup clutch 16 is engaged, power is transmitted between the front cover 10 and the shaft 50 by the frictional force of the lockup clutch 16.
[0033]
On the other hand, when the forward position is detected by the shift position sensor 60, the forward clutch 22 of the forward / reverse switching mechanism 8 is engaged and the reverse brake 23 is released. Then, the shaft 50 and the carrier 21 rotate integrally, and the torque of the shaft 50 is transmitted to the primary shaft 51. At this time, the shaft 50 and the primary shaft 51 rotate in the same direction.
[0034]
On the other hand, when the reverse position is detected by the shift position sensor 60, the forward clutch 22 is released and the reverse brake 23 is engaged. Then, when the engine torque is transmitted to the sun gear 17, the ring gear 18 serves as a reaction force element, and the torque of the sun gear 17 is transmitted to the primary shaft 51 via the carrier 21. In this case, the shaft 50 and the primary shaft 51 rotate in opposite directions.
[0035]
As described above, the engine torque is transmitted to the primary shaft 51, and on the basis of various signals input to the electronic control unit 34 and data stored in advance in the electronic control unit 34, the belt type continuously variable Control of the transmission 4 is executed. That is, the position of the movable sheave 53 in the axial direction of the primary shaft 51 is controlled, and the groove width of the primary pulley 24 is adjusted. Then, the winding radius of the belt 28 with respect to the primary pulley 24 continuously changes, and the gear ratio changes steplessly. Further, the position of the movable sheave 56 in the axial direction of the secondary shaft 55 is controlled, and the clamping pressure of the secondary pulley 25 with respect to the belt 28 is adjusted. In this manner, the capacity of the torque transmitted via the belt 28 between the primary pulley 24 and the secondary pulley 25 is controlled.
[0036]
In the belt-type continuously variable transmission 4 described above, power is transmitted between the primary pulley 24 and the secondary pulley 25 by a frictional force generated at a contact portion between the belt 28, the primary pulley 24, and the secondary pulley 25. For this reason, if the belt 28 slips, the power transmission efficiency of the belt-type continuously variable transmission 4 may be reduced, and the belt-type continuously variable transmission 4 is a component that is involved in torque transmission. Parts such as the belt 28, the primary pulley 24, and the secondary pulley 25 may be worn or seized, and the durability of these parts may be impaired. In order to avoid this problem, the clamping pressure applied to the belt 28 is determined based on the torque input to the belt-type continuously variable transmission 4, specifically, the slip amount of the belt 28 is less than a predetermined amount. The clamping pressure can be controlled to a low level.
[0037]
The “slip of the belt 28” means “torque input to the belt-type continuously variable transmission 4 rather than the torque capacity of the belt-type continuously variable transmission 4 determined based on the clamping pressure applied to the belt 28”. Means that the belt 28 and at least one of the primary pulley 24 or the secondary pulley 25 move relative to each other within a predetermined amount or more in the rotational direction at the contact portion.
[0038]
By the way, in the vehicle Ve shown in FIG. 2, the belt type continuously variable transmission 4 is disposed in the power transmission path between the engine 1 and the wheels 2. For this reason, when the engine torque is input to the belt-type continuously variable transmission 4 via the primary shaft 51 (hereinafter referred to as a positive input), the torque corresponding to the kinetic energy of the wheels 2 is applied to the secondary shaft 55. A case where the signal is input to the belt-type continuously variable transmission 4 via the route (hereinafter referred to as reverse input) can be considered. This reverse input occurs, for example, when the vehicle Ve travels on a rough road with a rough road surface or a road with steps. Therefore, prior to controlling the clamping pressure applied to the belt 28 as described above, depending on whether the direction of the torque input to the belt-type continuously variable transmission 4 is a reversible input that is a positive input, the belt 28. It is preferable to improve the accuracy of slip detection.
[0039]
A control example in the case where the content of the slip detection of the belt 28 is changed in accordance with the direction of torque input to the belt type continuously variable transmission 4 will be described based on the flowchart of FIG. First, the rotational speed Nin (i) of the primary shaft 51 and the rotational speed Nout (i) of the secondary shaft 55 are measured, and the gear ratio γ (i) of the belt type continuously variable transmission 4 is measured based on the measurement result. Is calculated (step S1).
[0040]
Following this step S1, the correlation coefficient k (i) is calculated using the latest measured data of the rotational speed Nin of the primary shaft 51 and Nout of the secondary shaft 55, respectively (step S2). The correlation coefficient k (i) is a coefficient obtained based on the input rotation speed and the output rotation speed in the belt type continuously variable transmission 4. The correlation coefficient k (i) can be expressed by a general formula as follows, and details thereof are described in, for example, the specification attached to the application of Japanese Patent Application No. 2001-302181.
[0041]
[Formula 1]

[0042]
Subsequent to step S2, when the direction of the torque input to the belt type continuously variable transmission 4 is a reverse input, a threshold kslp1 (i) when the belt 28 is assumed to slip is calculated (step S2). S3). Following this step S3, it is determined whether or not the correlation coefficient k (i) is less than or equal to a threshold value kslp1 (i) (step S4). If a negative determination is made in step S4, the process returns. On the other hand, when an affirmative determination is made in step S4, it is determined whether or not “control for determining which direction of torque input to the belt type continuously variable transmission 4 is performed” is performed. (Step S5).
[0043]
If the determination in step S5 is negative, "control for determining which direction of torque input to the belt type continuously variable transmission 4 is" is executed (step S6), and the process proceeds to step S7. A processing example of step S6 will be described later. On the other hand, if an affirmative determination is made in step S5, the process directly proceeds to step S7.
[0044]
In step S7, based on the result of “control for determining which direction of torque input to the belt type continuously variable transmission 4 is”, it is determined whether or not the slip is caused by reverse input (step S7). If the determination in step S7 is affirmative, it is determined that “the slip amount of the belt 28 is equal to or less than a threshold value” (step S8). Subsequent to step S8, control for reducing the amount of slip of the belt 28 is executed (step S9), and the process returns. In this step S9, for example, control for increasing the clamping pressure applied to the belt 28 is executed.
[0045]
If a negative determination is made in step S7, a threshold value kslp2 (i) when slippage of the belt 28 due to a positive input is assumed is calculated (step S10). Following this step S10, it is determined whether or not the correlation coefficient k (i) is less than or equal to a threshold value kslp2 (i) (step S11). If a positive determination is made in step S11, the process proceeds to step S8. If a negative determination is made in step S11, the process returns.
[0046]
In the above control, the threshold value kslp1 (i) and the threshold value kslp2 (i) can be set based on various parameters. Examples of the various parameters include a vehicle speed, a gear ratio of the belt-type continuously variable transmission 4, an actual speed of the belt-type continuously variable transmission 4, a vehicle acceleration / deceleration, a shift command value, and the like. Further, the threshold value kslp1 (i) and the threshold value kslp2 (i) are different in magnitude. Specifically, the threshold value kslp1 (i) is set larger than the threshold value kslp2 (i). The reason for this is to avoid erroneously determining that the slip of the belt 28 due to the positive input is “the slip of the belt 28 due to a sudden downshift”.
[0047]
Next, a first processing example of step S6 in FIG. 1 will be described based on the flowchart in FIG. First, the rotational speed Nout (i−n) of the secondary shaft 55 measured n times before the rotational speed Nout (i) of the secondary shaft 55 used for calculating the correlation coefficient k (i), and the secondary shaft 55 Based on the rotational speed Nout (in-1) of the secondary shaft 55 measured one time before the rotational speed Nout (in) of the shaft 55, the amount of change ΔNout in the rotational speed of the secondary shaft 55 over time. (I) is calculated (step S21).
[0048]
Following this step S21, the threshold value ΔNout corresponding to the driving condition of the vehicle Ve slp is calculated (step S22). Examples of the driving conditions of the vehicle Ve include a vehicle speed, a gear ratio of the belt-type continuously variable transmission 4, an actual speed of the belt-type continuously variable transmission 4, a vehicle acceleration / deceleration, a shift command value, and the like. Then, the time variation ΔNout (i) of the rotation speed of the secondary shaft 55 is the threshold value ΔNout. It is determined whether or not it is slp or less (step S23). If an affirmative determination is made in step S23, it is determined that the slip is caused by reverse input, and the process proceeds to step S7 in FIG. On the other hand, if a negative determination is made in step S23. It is determined that the slip is caused by positive input, and the process proceeds to step S7 in FIG.
[0049]
As described above, in the flowchart of FIG. 3, it is determined whether or not the input is reverse based on the time variation ΔNout of the rotational speed of the secondary shaft 55. The reason for this is that when the belt 28 slips due to reverse input, the rotational speed Nout of the secondary shaft 55 rapidly decreases, and the time variation ΔNout of the rotational speed of the secondary shaft 55 is reduced when the vehicle is decelerating ( This is because the rotational speed of the secondary shaft 55 at the time when the accelerator opening is fully closed is much smaller than the time variation ΔNout of the secondary shaft 55.
[0050]
Next, an example of a time chart corresponding to the flowchart of FIG. 3 is shown in FIGS. In the time charts of FIG. 4 and FIG. 5, the time change of the correlation coefficient k (i) is shown, the time change of the output shaft rotational speed is shown, and the time change of the output shaft rotational acceleration is shown. Note that the threshold change amount Δkslp1 and the threshold change amount Δkslp2 are shown to be substantially constant for convenience. First, the time chart of FIG. 4 corresponding to positive input will be described. Before time t1, correlation coefficient k (i) exceeds threshold change amount Δkslp1, and at time t1, correlation coefficient k (i) becomes equal to or less than threshold change amount Δkslp1. ing. That is, at time t1, an affirmative determination is made in step S3 in FIG.
[0051]
On the other hand, the output shaft rotational acceleration, that is, the temporal change amount ΔNout (i) of the rotational speed of the secondary shaft 55 is the threshold value ΔNout before and after time t1. slp is exceeded. That is, at time t1, an affirmative determination is made in step S4 in FIG. 1, and the process proceeds to step S25 in FIG. Next, at time t2 when the correlation coefficient k (i) becomes equal to or smaller than the threshold change amount Δkslp2, an affirmative determination is made in step S11 of FIG.
[0052]
Further, the time chart of FIG. 5 corresponding to reverse input will be described. Prior to time t1, the amount of change ΔNout (i) in the rotational speed of the secondary shaft 55 is equal to the threshold value ΔNou.tslp is exceeded. After time t1, the time variation ΔNout (i−n) of the rotational speed of the secondary shaft 55 is equal to the threshold value ΔNout. It is less than slp. That is, the process proceeds to step S24 in the flowchart of FIG. Further, at time t2, the correlation coefficient k (i) becomes equal to or smaller than the threshold change amount Δkslp1, and an affirmative determination is made in step S11 of FIG.
[0053]
Further, a second processing example of step S6 of FIG. 1 will be described based on the flowchart of FIG. First, the gear ratio γ of the belt type continuously variable transmission 4 immediately before the belt 28 slips. pre is calculated (step S31). here,
γ pre = γ (im)
Calculate as In the above formula, “i−m” means immediately before the belt 28 slips.
[0054]
Following this step S31, the gear ratio γ of the belt type continuously variable transmission 4 Based on pre, the rotational speed Nin (i) of the primary shaft 51, and the rotational speed Nout (i) of the secondary shaft 55, the relative slip speed Nslp of the belt 28 is calculated (step S32).
[0055]
In particular,
The relative slip speed of the belt 28 Nslp = Nin (i) / γ pre-Nout (i)
Is calculated as
[0056]
After step S32, the threshold value Nslp corresponding to the driving condition of the vehicle Ve max is calculated (step S33). Examples of the driving conditions of the vehicle Ve include a vehicle speed, a gear ratio of the belt-type continuously variable transmission 4, an actual speed of the belt-type continuously variable transmission 4, a vehicle acceleration / deceleration, a shift command value, and the like. Further, after step S33, the relative slip speed Nslp of the belt 28 is set to a threshold value Nslp. It is determined whether or not it is not more than max (step S34). When an affirmative determination is made in step S34, the process proceeds to step S7 in FIG. 1 via step S24. On the other hand, if a negative determination is made in step S34, the process proceeds to step S7 in FIG. 1 via step S25. The process in step S24 in FIG. 6 is the same as the process in step S24 in FIG. 3, and the process in step S25 in FIG. 6 is the same as the process in step S25 in FIG.
[0057]
As described above, in the flowchart of FIG. 6, the gear ratio of the belt type continuously variable transmission 4 is calculated based on the contact diameter of the belt 28 with respect to the primary pulley 24 and the secondary pulley 25, and the belt type continuously variable transmission 4. Based on the gear ratio and the rotational speed Nin of the primary shaft 51 and the rotational speed Nout of the secondary shaft 55, it is determined whether or not the input is reverse. As described above, in the flowchart of FIG. 6, the relative slip speed is calculated based on the gear ratio (belt wrapping diameter with respect to the pulley) immediately before the belt slip occurs, and the positive input is based on the relative slip speed. Or the process which discriminate | determines reverse input is performed.
[0058]
Next, an example of a time chart corresponding to the flowchart of FIG. 6 is shown in FIGS. 7 and FIG. 8, the time change of the correlation coefficient k (i) is shown, the time change of the gear ratio of the belt type continuously variable transmission 4 is shown, the time change of the output speed and the input rotation. The change in speed over time is shown. In the time charts of FIGS. 7 and 8, the threshold change amount Δkslp1 and the threshold change amount Δkslp2 are shown substantially constant for convenience. Further, in a state where no slip occurs in the belt, the input rotation speed is expressed as Nin (i) / γ in order to indicate the input rotation speed and the output rotation speed as the same rotation speed regardless of the gear ratio. pre is used.
[0059]
First, the time chart of FIG. 7 corresponding to positive input will be described. Prior to time t1, the correlation coefficient k (i) exceeds the threshold change amount Δkslp1, and the input rotational speed (broken line) and the output rotational speed (solid line) match. At time t1, the gear ratio starts to increase and a difference occurs between the input rotation speed and the output rotation speed. Specifically, the input rotation speed is higher than the output rotation speed.
[0060]
As described above, when the belt starts slipping at time t1, the gear ratio of the belt type continuously variable transmission immediately before the belt slips is calculated. Further, at time t2, the transmission ratio starts to decrease, and correlation coefficient k (i) becomes equal to or less than the threshold change amount Δkslp1, and thereafter, correlation coefficient k (i) becomes the threshold at time t3. The amount of change Δkslp2 or less. That is, a positive determination is made in step S11 of FIG.
[0061]
Next, the time chart of FIG. 8 corresponding to reverse input will be described. Prior to time t1, the correlation coefficient k (i) exceeds the threshold change amount Δkslp1, and the input rotation speed and the output rotation speed coincide with each other. At time t1, the gear ratio starts to increase and a difference occurs between the input rotation speed and the output rotation speed. Specifically, the output rotation speed is higher than the input rotation speed.
[0062]
As described above, when the belt starts slipping at time t1, the gear ratio of the belt type continuously variable transmission immediately before the belt slips is calculated. Furthermore, at time t2, the speed ratio starts to decrease, and the correlation coefficient k (i) becomes equal to or less than the threshold change amount Δkslp1, and it is determined that the slip is caused by reverse input. Thereafter, the correlation coefficient k (i) is larger than the threshold change amount Δkslp1. 4, 5, 7, and 8, there is no correspondence between the times shown in different diagrams.
[0063]
As described above, according to the control example of FIG. 1, the slip state of the belt 28 is detected based on the correspondence between the same correlation coefficient k (i) and the threshold kslp used for the slip determination of the belt 28. In this case, it is determined whether the direction of the torque input to the belt type continuously variable transmission 4 is the forward direction or the reverse direction, and the threshold value kslp is set based on the determination result. Therefore, the slip detection accuracy of the belt 28 of the belt type continuously variable transmission 4 can be improved. Further, since it is determined whether or not the reverse input is based on the amount of change in the rotational speed of the secondary shaft 55, the direction of the torque input to the belt type continuously variable transmission 4 can be detected with high accuracy. .
[0064]
  The control example in FIG. 1 is a control example in which the threshold value to be compared with the correlation coefficient k (i) is changed depending on whether the input is reverse or not, but the threshold value for determining whether or not the belt 28 slips. Also included in the invention of each claim is a control for changing the threshold for judging the degree of slipping of the belt 28 (slip amount, slip speed, number of occurrences of slip, etc.) depending on whether or not it is reverse input.The
[0065]
Here, the correspondence between the functional means shown in FIG. 1, FIG. 3 and FIG. 6 and the configuration of the present invention will be described. Steps S1 to S8, Step S10 and Step S11 shown in FIG. Steps S21 to S25 shown in FIG. 3 and Steps S31 to S34, Step S24 and Step S25 shown in FIG. 6 correspond to the slip determination means of the present invention. Further, whether or not the belt 28 slips, the degree of slipping of the belt 28, the relative slip speed of the belt 28, and the like correspond to the slipping state that occurs between the first rotating member and the second rotating member of the present invention. The correlation coefficient k (i) corresponds to the “physical quantity based on the first rotating member and the second rotating member” of the present invention, and the threshold kslp corresponds to the reference value of the present invention. The threshold value kslp1 (i) corresponds to the “reference value selected when torque is transmitted from the second rotating member to the first rotating member” of the present invention, and the threshold value kslp2 (i) is This corresponds to the “reference value selected when torque is transmitted from the first rotating member to the second rotating member” in the invention, and the threshold value ΔNout. slp corresponds to the predetermined amount of the present invention.
[0066]
2 will be described. The primary shaft 51 and the primary pulley 24 correspond to the first rotating member of the present invention, and the secondary pulley 25 and the secondary pulley 24 will be described. The shaft 55 corresponds to the second rotating member of the present invention, the belt type continuously variable transmission 4 corresponds to the power transmission mechanism of the present invention, and the engine and the electric motor correspond to the driving force source of the present invention.
[0067]
In the power train of FIG. 1, a belt-type continuously variable transmission 4 is used as a continuously variable transmission capable of continuously controlling the gear ratio. However, other continuously variable transmissions such as a toroidal transmission are used. The present invention can also be applied to a vehicle having a continuously variable transmission. A toroidal continuously variable transmission is a transmission having an input disk and an output disk having toroidal surfaces, and a power roller in contact with each disk. Lubricating oil is present on the contact surface between each disk and the power roller. The power roller is moved linearly in a plane perpendicular to the axis of each disk, and the contact radius between the power roller and each disk is adjusted, so that the gear ratio between the input disk and the output disk is increased. Be controlled. Further, by adjusting the contact surface pressure between each disk and the power roller, the capacity of torque transmitted between the input disk and the output disk is controlled.
[0068]
That is, when the contact surface pressure between each disk and the power roller is increased, the lubricating oil becomes glassy, and power is transmitted between the input disk and the output disk by so-called traction transmission (shearing force). As described above, a hydraulic servo mechanism for adjusting the contact surface pressure between each disk and the power roller is provided. The hydraulic servo mechanism has a piston and a first hydraulic chamber that operates each piston. A hydraulic servo mechanism is provided for moving the power roller in a straight line within a plane perpendicular to the axis of each disk. This hydraulic servomechanism has a second hydraulic chamber. In this toroidal-type continuously variable transmission, the torque of the driving force source is transmitted from the input disk to the output disk via the power roller, and the torque due to the kinetic energy of the wheels is transmitted from the output disk to the power roller. And reverse input transmitted to the input disk. The torque capacity in this toroidal continuously variable transmission is controlled by the axial clamping force applied to each disk in accordance with the hydraulic pressure in the first hydraulic chamber.
[0069]
The inventions of claims 1 to 7 can be applied to such a toroidal-type continuously variable transmission. In this case, the input disk corresponds to the first rotating member of the present invention, the output disk corresponds to the second rotating member of the present invention, and the sliding state of the power roller corresponds to the “first rotating member of the present invention. This corresponds to the “sliding state” occurring between the second rotating member and the second rotating member. And the threshold value used for the detection of the slip state of the power roller is changed according to the direction of torque input to the toroidal-type continuously variable transmission.
[0070]
Furthermore, the invention of claims 1 to 7 can be applied to a vehicle in which a power transmission mechanism such as a friction clutch is provided between the driving force source and the wheels. The arrangement position of the friction clutch is either a power transmission path between the driving force source and the transmission, a power transmission path between the transmission and the wheels, or a part of the stepped transmission. Also good. This friction clutch is composed of, for example, a friction material provided on the first rotating member and a friction material provided on the second rotating member. The clutch engagement pressure is controlled by a hydraulic control device (not shown) or the like.
[0071]
Furthermore, a positive input in which the torque of the driving force source is transmitted to the second rotating member via the first rotating member, and a torque corresponding to the kinetic energy of the wheel is transmitted to the second rotating member via the second rotating member. The reverse input transmitted to one rotating member occurs. In a vehicle having this clutch, the slipping state generated between the friction materials corresponds to the slipping state of the present invention. Then, the threshold used for detecting the slipping state of the clutch is changed according to the direction of torque input to the clutch.
[0072]
As described above, according to the present invention, the first rotating member and the second rotating member are connected via an inclusion (for example, a belt, a power roller, lubricating oil) so that power can be transmitted indirectly. First power transmission mechanism (for example, belt-type continuously variable transmission, toroidal-type continuously variable transmission) or second power having a configuration in which the first rotating member and the second rotating member are in direct contact with each other The present invention can be applied to any transmission mechanism (friction clutch).
[0073]
And
(1) In the first power transmission mechanism, a slipping state at a contact portion between the first rotating member or the second rotating member and the inclusion is detected.
In addition,
(2) In the toroidal continuously variable transmission, both the power roller and the lubricating oil can be grasped as inclusions, and in this case, the sliding state at the contact portion (boundary surface) between the inclusions is detected. You can also
[0074]
On the contrary,
(3) In the second power transmission mechanism, the slipping state at the contact portion between the first rotating member and the second rotating member is detected.
[0075]
Therefore, in the first to seventh aspects of the invention, the “sliding state generated between the first rotating member and the second rotating member” includes the sliding state described in the above (1) none (3). .
[0076]
Here, the characteristic configuration disclosed in this embodiment will be described as follows. In other words, when torque is transmitted between the first rotating member and the second rotating member, the slippage of the transmission that detects the slipping state between the first rotating member and the second rotating member. In the detection device, when torque is transmitted from the first rotating member to the second rotating member, and when torque is transmitted from the second rotating member to the first rotating member, A slip detection device for a transmission comprising a slip determination means for changing a reference value for detecting a slip state generated between a first rotating member and a second rotating member.
[0077]
By the way, “slip judging means” described in each claim of “claims” of this specification can be read as “slip judging device” or “slip judging controller”. In this case, the electronic control device 34 described in the embodiment corresponds to a “slip determination device” and a “slip determination controller”. Further, the “power transmission mechanism” described in each claim can be read as “actuator” or “variator”. Furthermore, “slip judging means” described in each claim may be read as “slip judging step”, and “slip detecting device for power transmission mechanism” may be read as “slip detecting method for power transmission mechanism”. it can.
[0078]
【The invention's effect】
  As explained above, according to the invention of claim 1In the case where the correlation coefficient obtained based on the first rotating member and the second rotating member is compared with the reference value to detect the slipping state, when the correlation coefficient is equal to or less than the reference value, It is determined that the relative slip speed between the first rotating member and the second rotating member is a predetermined amount or more. Moreover, in order to set the magnitude of the reference value based on the direction of torque input to the power transmission mechanism,The detection accuracy of the slip state of the power transmission mechanism is improved.
[0081]
  ClaimAccording to invention of Claim 2, of Claim 1In addition to the same effects as the invention, the torque of the driving force source is transmitted to the second rotating member via the first rotating member, and the torque of the wheel is the second rotation. The reference value can be changed between the case where the reference value is transmitted to the first rotating member via the member, and the detection accuracy of the sliding state is further improved.
[0082]
  ClaimAccording to invention of Claim 3, of Claim 2In addition to the same effects as the invention, slipping when the torque of the driving force source is transmitted from the first rotating member to the second rotating member and the torque of the wheel from the second rotating member The slip when transmitted to one rotating member can be identified based on the amount of change in the rotational speed of the second rotating member over time.
[0083]
  ClaimAccording to the invention of claim 4 of claim 3,In addition to obtaining the same effect as the invention, when the amount of time change in the rotational speed of the second rotating member is less than or equal to a predetermined amount, the torque of the wheel is transmitted from the second rotating member to the first rotating member. Judge that it is slipping when it is done. On the other hand, when the time change amount of the rotation speed of the second rotating member exceeds a predetermined amount, the torque of the driving force source is transmitted from the first rotating member to the second rotating member. It is judged that this is a slip. Therefore, it is possible to further improve the slip detection accuracy.
[0084]
  ClaimAccording to invention of Claim 5, Claims 1 thru | or 4 ofIn addition to obtaining the same effect as any of the inventions, it is possible to improve the belt slip detection accuracy of the belt type continuously variable transmission.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an example of a detection device for a power transmission mechanism of the present invention.
FIG. 2 is a conceptual diagram showing a power train of a vehicle to which the power transmission mechanism detection device of the present invention can be applied and a control system thereof.
FIG. 3 is a flowchart showing a specific example of a part of the processing of the flowchart shown in FIG. 1;
4 is an example of a time chart corresponding to the flowcharts shown in FIGS. 1 and 3. FIG.
FIG. 5 is an example of a time chart corresponding to the flowcharts shown in FIGS. 1 and 3;
6 is a flowchart showing a specific example of a part of the processing of the flowchart shown in FIG. 1. FIG.
7 is an example of a time chart corresponding to the flowcharts shown in FIGS. 1 and 6. FIG.
8 is an example of a time chart corresponding to the flowcharts shown in FIGS. 1 and 6. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine (drive force source), 2 ... Wheel, 4 ... Belt type continuously variable transmission, 24 ... Primary pulley, 25 ... Secondary pulley, 28 ... Belt, 34 ... Electronic control unit, 51 ... Primary shaft, 55 ... Secondary Shaft, Ve ... Vehicle.

Claims (5)

Slip detection of a power transmission mechanism that detects a slip state between the first rotating member and the second rotating member when torque is transmitted between the first rotating member and the second rotating member. In the device
When the torque is transmitted from the first rotating member to the second rotating member, and when the torque is transmitted from the second rotating member to the first rotating member, the first rotation is performed. e Bei slip determination means for changing a reference value for detecting a slip state between the member and the second rotary member,
The slip judging means is
A slip state between the first rotating member and the second rotating member is detected based on a comparison result between a physical quantity based on the first rotating member and the second rotating member and the reference value. Function and
A function for obtaining a correlation coefficient based on the first rotating member and the second rotating member as the physical quantity;
A function of determining that a relative slip speed between the first rotating member and the second rotating member is a predetermined amount or more when the correlation coefficient is equal to or less than a reference value;
A value selected as the reference value when torque is transmitted from the first rotating member to the second rotating member, and when torque is transmitted from the second rotating member to the first rotating member A slip detection device for a power transmission mechanism , further comprising a function of setting a value smaller than a value selected as the reference value . The torque of the driving force source of the vehicle is transmitted to the second rotating member via the first rotating member, and the torque of the wheel is transmitted to the second rotating member via the second rotating member. The slip detection device for a power transmission mechanism according to claim 1, wherein the slip detection device is transmitted to one rotating member . Said slip determining means, slippage or occurs when torque before Symbol driving power source is transmitted to the second rotary member from the first rotary member, or torque of the wheels from the second rotational member 3. The method according to claim 2, further comprising a function of determining whether or not the slip is generated when transmitted to the first rotating member based on a temporal change amount of the rotation speed of the second rotating member. The slip detection device of the power transmission mechanism described. The slip judging means is
When the temporal change amount of the rotation speed of the second rotating member is equal to or less than a predetermined amount, the slip is generated when the torque of the wheel is transmitted from the second rotating member to the first rotating member. The ability to judge,
If the amount of time change in the rotational speed of the second rotating member exceeds a predetermined amount, slip that occurs when the torque of the driving force source is transmitted from the first rotating member to the second rotating member. With the ability to determine
The slip detection device for a power transmission mechanism according to claim 3, further comprising: And before Symbol belt-type continuously variable transmission wound the first rotary member and the second endless belt to a rotating member of is provided between the first rotary member and the second rotary member 5. The slip detection device for a power transmission mechanism according to claim 1, wherein torque is transmitted through the belt .

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