JP3883484B2

JP3883484B2 - Work vehicle turning control device

Info

Publication number: JP3883484B2
Application number: JP2002285039A
Authority: JP
Inventors: 之史山中; 吉弘上田; 繁樹林; 裕治加藤; 太池田; 勝秀加藤
Original assignee: Kubota Corp
Current assignee: Kubota Corp
Priority date: 2002-09-30
Filing date: 2002-09-30
Publication date: 2007-02-21
Anticipated expiration: 2022-09-30
Also published as: JP2004114990A

Description

【０００１】
【発明の属する技術分野】
本発明は、左右一対の走行装置の走行速度を変速する一対の無段変速装置と、その一対の無段変速装置を各別に変速操作自在な変速操作手段と、直進及び旋回を指令自在で且つ旋回するときの旋回半径の大きさを指令自在な旋回指令手段と、前記旋回指令手段の指令情報に基づいて直進及び旋回を行うべく前記変速操作手段を作動させる旋回制御を実行する制御手段とが備えられている作業車の旋回制御装置に関する。
【０００２】
【従来の技術】
上記構成の作業車の走行制御装置は、例えばコンバイン等の作業車に適用されるものであり、従来では、次のような構成のものがあった。
つまり、前記一対の無段変速装置として静油圧式の無段変速装置を用いて、変速操作手段として一対の電動モータが設けられ、一対の無段変速装置夫々の出力回転速度を一対の回転センサにて検出して、これらの回転センサの検出値が夫々目標とする出力回転速度になるように各電動モータにより一対の無段変速装置を作動させるように構成され、しかも、これらの無段変速装置の伝動下手側に動力伝達を入り切り自在な操向クラッチと各走行装置を制動自在な操向ブレーキとが備えられ、前記旋回制御として、次のような処理を実行する構成のものがあった。つまり、旋回モードとして、緩旋回モード、ブレーキ旋回モード、スピン旋回モードがあり、そのうちの緩旋回モードでは、旋回指令手段としてのパワステレバーの直進指令位置から離れる方向への移動量が大きくなって小さい旋回半径を指令するほど、左右一対の無段変速装置のうち旋回中心から離れる側の無段変速装置の出力回転速度を所定速度に維持しながら、旋回中心側の無段変速装置を無段階に減速させる形態で、一対の無段変速装置の回転速度の比率を変化させることにより旋回するときの旋回半径を小さくさせるように変速操作手段の作動を制御するように構成したものがあった。尚、ブレーキ旋回モードでは、パワステレバーの旋回用の操作角度が大になると旋回中心側の走行装置に対して操向クラッチを切り且つ操向ブレーキを作動させる状態で旋回を行い、スピン旋回モードでは、操向クラッチの切り及び操向ブレーキの作動に加えて、パワステレバーの旋回用の操作角度が大になると、旋回中心側の走行装置が逆回転する状態に切り換わるようになっている（例えば、特許文献１参照。）。
【０００３】
【特許文献１】
特開平８−１７２８７１号公報（第３頁―第５頁、図４、図６）
【０００４】
【発明が解決しようとする課題】
上記従来構成においては、緩旋回モードで旋回走行する場合に、左右一対の無段変速装置のうち旋回中心から離れる側の無段変速装置の出力回転速度を設定速度に維持して、旋回中心側の無段変速装置を減速させて一対の無段変速装置の回転速度の比率を変化させる形態で、一対の無段変速装置夫々の出力回転速度が夫々目標とする出力回転速度になるように変速操作手段を作動させるように構成されており、前記目標回転速度として零速が指令されたような場合に次のような不都合が発生するという不利な点があった。
【０００５】
つまり、上記構成では、前記目標回転速度として零速が指令されたような場合であっても、回転センサにて検出される旋回中心側の無段変速装置の出力回転速度が目標回転速度つまり零速になるように、変速操作手段としての電動モータにより変速用の被操作体を零速に対応する位置に調整しようとする。しかし、コンバイン等の作業車にあっては圃場等などの不整地を走行することが多く、このような不整地においては走行装置に対する走行負荷が大になるので、旋回中心側の走行装置を零速にして旋回走行している場合であっても、旋回中心側の走行装置が地面との摩擦によって反対側の走行装置の走行方向と同じ方向に連れ回りしてしまうことがある。
【０００６】
このような連れ回りが発生すると、変速用の被操作体を零速に対応する位置に調整しているにもかかわらず、回転センサの検出値が零でなく所定の回転速度で回転している状態として誤って検出することになる。そして、その状態から所定の回転速度分だけ減速させるように変速用の被操作体を零速に対応する位置よりも更に減速側、つまり、中立位置を越えて変速出力がそれまでの正転方向から回転方向が逆となる逆転方向に対応する操作位置にまで変速操作することになる。
【０００７】
しかし、そのように変速用の被操作体が逆転方向になる操作位置にまで操作さていることが検出されると、制御手段が無段変速装置の変速出力が逆転方向での回転であると判断して、今度はその逆転方向での回転を零速にすべく、直ちに変速用の被操作体を正転方向における元の位置にまで戻すように制御する。そして、又、上記したように、その状態から所定の回転速度分だけ減速させるように変速用の被操作体を零速に対応する位置よりも更に減速側に操作するといったことを繰り返し実行することになる。その結果、変速用の被操作体は中立位置付近を正転状態と逆転状態とに交互に切り換わり、出力回転速度は零速に収束することなく、上記したような連れ回り状態が継続することになり、旋回中心側の走行装置を零速にさせた状態での適正な旋回が行えないものとなる不利がある。
【０００８】
ところで、上記従来構成においては、旋回モードをブレーキ旋回モードに切り換えて、旋回中心側の走行装置に対する操向クラッチを切り操作して操向ブレーキを操作することで、旋回中心側の走行装置を零速にさせて旋回を行うことができる構成となっているが、このような構成では、左右一対の無段変速装置の操作だけでなく操向ブレーキ等の機械的な制動手段による旋回中心側の走行装置に対する制動操作を実行しなければならず構成が複雑になる不利がある。
【０００９】
本発明はかかる点に着目してなされたものであり、その目的は、機械的な制動手段による制動操作を行うといった構成の複雑化を招くことなく、旋回中心側の走行装置を零速にさせた状態で適正な旋回を行うことが可能となる作業車の旋回制御装置を提供する点にある。
【００１０】
【課題を解決するための手段】
請求項１に記載の作業車の旋回制御装置は、左右一対の走行装置の走行速度を変速する一対の無段変速装置と、その一対の無段変速装置を各別に変速操作自在な変速操作手段と、直進及び旋回を指令自在で且つ旋回するときの旋回半径の大きさを指令自在な旋回指令手段と、前記旋回指令手段の指令情報に基づいて直進及び旋回を行うべく前記変速操作手段を作動させる旋回制御を実行する制御手段とが備えられているものであって、前記一対の無段変速装置の夫々における変速用の被操作体の変速位置を各別に検出する一対の変速位置検出手段と、前記一対の無段変速装置の出力回転速度を各別に検出する一対の変速出力検出手段とが備えられ、前記制御手段が、前記旋回制御として、前記変速出力検出手段にて検出される旋回中心から離れる側に位置する無段変速装置の出力回転速度を基準として、左右一対の無段変速装置の出力回転速度の速度比率が前記旋回指令手段にて指令される旋回半径に対応する速度比率となるように前記旋回中心側に位置する無段変速装置の目標回転速度を求める目標回転速度設定処理、及び、その目標回転速度設定処理にて求められる前記目標回転速度が零速でないときは、前記旋回中心側に位置する無段変速装置の出力回転速度が前記目標回転速度になるように前記変速出力検出手段の検出情報に基づいて前記変速操作手段を作動させ、且つ、前記目標回転速度設定処理にて求められる前記目標回転速度が零速であるときは、前記旋回中心側に位置する無段変速装置における変速用の被操作体の変速位置が零速に対応する目標変速位置になるように前記変速位置検出手段の検出情報に基づいて前記変速操作手段を作動させる旋回用調整処理の夫々を実行するように構成されていることを特徴とする。
【００１１】
すなわち、旋回中心から離れる側に位置する無段変速装置の出力回転速度を基準として、左右一対の無段変速装置の出力回転速度の速度比率が旋回指令手段にて指令される旋回半径に対応する速度比率となるように旋回中心側に位置する無段変速装置の目標回転速度を求め、その目標回転速度が零速でないときは、旋回中心側に位置する無段変速装置の出力回転速度が目標回転速度になるように変速操作手段を作動させる。このように、左右一対の走行装置が旋回指令手段にて指令される旋回半径に対応する速度比率で走行するので適正な旋回が行われることになる。
【００１２】
そして、前記目標回転速度が零速であるときは、旋回中心側に位置する無段変速装置における変速用の被操作体の変速位置が零速に対応する目標変速位置になるように変速位置検出手段の検出情報に基づいて変速操作手段を作動させるので、旋回中心側の無段変速装置における変速用の被操作体の変速位置が零速に対応する目標変速位置に位置保持されることになり変速状態が変化することがなく、機械的な制動手段による制動操作を行わなくても、旋回中心側に位置する走行装置が速度零の状態を維持することができ、適正な旋回を行うことが可能となる。
【００１３】
従って、機械的な制動手段による制動操作を行うといった構成の複雑化を招くことなく、旋回中心側の走行装置を零速にさせた状態で適正な旋回を行うことが可能となる作業車の旋回制御装置を提供できるに至った。
【００１４】
請求項２に記載の作業車の旋回制御装置は、請求項１において、前記旋回指令手段にて前記直進が指令されているときにおける目標車速を指令する車速指令手段が備えられ、前記制御手段が、前記旋回制御において、前記旋回中心から離れる側に位置する無段変速装置における変速用の被操作体の変速位置が前記目標車速に対応する目標変速位置になるように、前記変速位置検出手段の検出情報に基づいて前記変速操作手段を作動させるように構成されていることを特徴とする。
【００１５】
すなわち、旋回中心から離れる側に位置する無段変速装置における変速用の被操作体の変速位置が、車速指令手段にて指令される目標車速に対応する目標変速位置になるように変速操作手段を作動させるのである。このように、速度比率の基準となる側の無段変速装置は、被操作体の変速位置が目標変速位置になるように制御されるので、例えば、走行負荷の変動等によって出力回転速度が変化しても被操作体の変速位置に対する目標変速位置は変化しない。そして、反対側の無段変速装置の出力回転速度は、基準側の無段変速装置の出力回転速度を基準として、旋回指令手段にて指令される旋回半径に対応する速度比率になるように速度調整される。つまり、走行負荷の変動等によりエンジン回転速度が変動するような場合においては、左右一対の無段変速装置は出力回転速度が変化するものの、左右一対の無段変速装置は、ほぼ同じような速度比率を維持して追従しながら変化することになり、誤差の少ない状態で旋回指令手段にて指令された旋回半径にて適正に旋回走行することが可能となる。
【００１６】
請求項３記載の作業車の旋回制御装置は、請求項１又は２において、前記旋回指令手段が、直進を指令する直進指令位置及び旋回を指令する旋回操作用操作領域の全範囲にわたり移動操作自在な操作具を備えて、その操作具が、前記旋回操作用操作領域において直進指令位置から離れる方向へ移動されるほど小さい旋回半径を指令するように構成され、前記制御手段が、前記目標回転速度設定処理として、前記旋回指令手段にて指令される旋回半径が小さくなるほど漸次低速となり、且つ、前記旋回指令手段にて最も小さい旋回半径が指令されたときに零速とする形態で、前記旋回中心側に位置する無段変速装置の目標回転速度を求める処理を実行するように構成されていることを特徴とする。
【００１７】
すなわち、旋回指令手段の操作具が旋回操作用操作領域において直進指令位置から離れる方向へ移動されるほど小さい旋回半径が指令されるが、そのとき指令される旋回半径が小さくなるほど漸次低速となるように旋回中心側に位置する無段変速装置の目標回転速度が求められ、最も小さい旋回半径が指令されたときには前記目標回転速度として零速が指令されることになる。
【００１８】
従って、最大操作位置まで操作して最も小さい旋回半径が指令されたときには、変速用の被操作体の変速位置が零速に対応する目標変速位置になるように変速操作手段を作動させるので適正な旋回を行うことが可能となる。
【００１９】
請求項４記載の作業車の旋回制御装置は、請求項１又は２において前記旋回指令手段が、直進を指令する直進指令位置及び旋回を指令する旋回操作用操作領域の全範囲にわたり移動操作自在な操作具を備えて、その操作具が、前記旋回操作用操作領域において直進指令位置から離れる方向へ移動されるほど小さい旋回半径を指令するように構成され、前記制御手段が、前記目標回転速度設定処理として、前記旋回指令手段にて指令される旋回半径が小さくなるほど漸次低速にして零速とし且つその後において逆回転状態で漸次高速にする形態で、前記旋回中心側に位置する無段変速装置の目標回転速度を求める処理を実行するように構成されていることを特徴とする。
【００２０】
すなわち、旋回指令手段の操作具が旋回操作用操作領域において直進指令位置から離れる方向へ移動されるほど小さい旋回半径が指令されるが、そのとき指令される旋回半径が小さくなるほど零速になるように漸次低速となり、且つその後において逆回転状態で漸次高速にする形態で旋回中心側に位置する無段変速装置の目標回転速度を求めることになる。つまり、操作具を旋回操作用操作領域において直進指令位置から離れる方向へ移動させると、旋回中心側に位置する無段変速装置の目標回転速度が漸次低速となり、操作具を旋回操作用操作領域の途中の所定位置まで操作すると目標回転速度が零速となる。そして、更に操作具を移動操作すると、目標回転速度が逆回転状態で漸次高速になり、旋回中心側に位置する走行装置が逆回転状態となって零速で旋回するものに比べて更に旋回半径を小さくして小回り旋回が行えるものとなる。
【００２１】
従って、操作具を旋回操作用操作領域の途中の所定位置に操作して目標回転速度が零速になると、変速用の被操作体の変速位置が零速に対応する目標変速位置になるように変速操作手段を作動させるので、このような場合においても適正な旋回が行われることになる。
【００２２】
請求項５記載の作業車の旋回制御装置は、請求項１〜４のいずれかにおいて、前記一対の無段変速装置の夫々が静油圧式無段変速装置にて構成されていることを特徴とする。
【００２３】
静油圧式無段変速装置は、変速用の被操作体を操作することで、正転方向並びに逆転方向の夫々に無段階に変速操作することが可能であり、正転方向での変速操作域と逆転方向での変速操作域との間に速度零となる中立域があり、変速用の被操作体をこの中立域に操作することで変速出力を零速にすることができる。
従って、左右一対の走行装置を各別に零速を含む状態で前進方向並びに後進方向の夫々に無段階に変速操作することにより、旋回半径を漸次変更させて滑らかな旋回走行を行うことができる。
【００２４】
【発明の実施の形態】
以下、本発明に係る作業車の旋回制御装置の実施形態を作業車の一例としてのコンバインに適用した場合について図面に基づいて説明する。
【００２５】
図１に作業車の一例であるコンバインの全体側面が示されており、このコンバインは、走行装置の一例である左右一対のクローラ式の走行装置１Ｒ、１Ｌの駆動で走行する走行機体２の前部に、植立穀稈を刈り取って後方に向けて搬送する刈取搬送装置３を昇降可能に連結し、走行機体２に、刈取搬送装置３からの刈取穀稈を受け取って脱穀処理並びに選別処理を実行する脱穀装置４と、脱穀装置４からの穀粒を貯留する穀粒タンク５とを搭載するとともに、穀粒タンク５の前方箇所に搭乗運転部６を形成することによって構成されている。
【００２６】
図２に示すように、このコンバインは、エンジン７からの動力を、ベルトテンション式の主クラッチ８を介してミッションケース９の入力軸１０に伝達し、この入力軸１０から走行用の一対の無段変速装置１１Ｒ、１１Ｌに分配伝達し、走行用の一方の無段変速装置１１Ｌによる変速後の動力を左側のギヤ式の副変速装置１３Ｌを介して左側のクローラ式走行装置１Ｌに伝達し、走行用の他方の無段変速装置１１Ｒによる変速後の動力を、右側のギヤ式の副変速装置１３Ｒを介して右側のクローラ式走行装置１Ｒに伝達するようにして走行駆動用の伝動機構を構成している。一方、エンジン７からの動力が作業用の無段変速装置１２にも供給され、その作業用の無段変速装置１２による変速後の動力を、ベルトテンション式の刈取クラッチ１４を介して刈取搬送装置３に伝達するようにして刈取作業用の伝動機構を構成している。左右のギヤ式の副変速装置１３Ｒ、１３Ｌは、前記各無段変速装置１１Ｒ、１１Ｌの変速後の動力を高低２段に切り換え自在に構成されている。又、搭乗運転部６には、前後方向に揺動操作可能な単一の副変速レバー２５が設けられ、この副変速レバー２５は、図示しない連係機構を介してギヤ式の副変速機構１３Ｒ、１３Ｌに連係されており、副変速レバー２５の操作によって、走行用の各無段変速装置１１Ｒ、１１Ｌによる変速後の動力を高低２段に変速できるようになっている。
【００２７】
走行用の各無段変速装置１１Ｒ、１１Ｌは、アキシャルプランジャ形式で可変容量型のピストンポンプ１９とピストンモータ２０とを夫々備えて静油圧式の無段変速装置として構成され、作業用の無段変速装置１２も同様に、アキシャルプランジャ形式で可変容量型のピストンポンプ２１とピストンモータ２２とを備えて静油圧式無段変速装置として構成され、左右の走行装置１Ｒ、１Ｌ夫々の走行方向を前進方向並びに後進方向に切り換え且つ走行速度を無段階に変速することができる構成となっている。
【００２８】
そして、図３に示すように、走行用の各無段変速装置１１Ｒ、１１Ｌを各別に変速操作する変速操作手段としての油圧式の走行用操作機構３０と、作業用の無段変速装置１２を変速操作する油圧式の作業用操作機構３６とが夫々備えられている。前記走行用操作機構３０は、走行用の各無段変速装置１１Ｒ、１１Ｌの夫々におけるトラニオン軸２９（被操作体の一例）に連動連結された一対の複動型の油圧シリンダ３３Ｒ、３３Ｌと、これらの各油圧シリンダ３３Ｒ、３３Ｌに対する正逆方向夫々の操作に対応する一対の油室に作動油を供給する状態と供給を停止する状態とに切り換え自在な一対の２位置切換式の給油用電磁弁３４Ａと、前記一対の油室から作動油を排出する状態と排出を停止する状態とに切り換え自在な一対の２位置切換式の排油用電磁弁３４Ｂとを備えて構成されている。前記各油圧シリンダ３３Ｒ、３３Ｌは、内装されるバネの付勢力により中立位置に復帰付勢される構成となっている。
【００２９】
前記作業用操作機構３６も同様に、作業用の無段変速装置１２におけるトラニオン軸３７に連動連結されるとともに、内装されるバネの付勢力により中立位置に復帰付勢される構成の複動型の油圧シリンダ４０と、この油圧シリンダ４０に対する正逆方向夫々の操作に対応する一対の油室に作動油を供給する状態と供給を停止する状態とに切り換え自在な一対の２位置切換式の給油用電磁弁４１Ａと、前記一対の油室から作動油を排出する状態と排出を停止する状態とに切り換え自在な一対の２位置切換式の排油用電磁弁４１Ｂとを備えて構成されている。
【００３０】
前記各給油用電磁弁３４Ａ、４１Ａは、バネの付勢力によってスプールを給油停止状態に移動付勢する構成となっており、ソレノイドによる電磁力によってバネの付勢力に抗してスプールを移動操作して作動油を供給する状態に切り換える構成となっており、又、前記各排油用電磁弁３４Ｂ、４１Ｂは、バネの付勢力によってスプールを排出状態に移動付勢される構成となっており、ソレノイドによる電磁力によってバネの付勢力に抗してスプールを移動操作して作動油の排出を停止する状態に切り換わる構成となっている。
【００３１】
上記したような無段変速装置１１Ｒ、１１Ｌの変速動作の概略について説明を加えると、図４に示すように、トラニオン軸２９の変速位置が中立域にあれば変速出力（走行速度）は零となり、トラニオン軸２９の変速位置がその中立域から所定方向に回動操作されると前進方向への走行速度が無段階に増速操作され、トラニオン軸２９が中立域から所定方向と反対方向に回動操作されると後進方向への走行速度が無段階に増速操作される構成となっている。
【００３２】
搭乗運転部６には、走行停止を指令する停止用指令位置としての中立位置を含む所定操作範囲内で車体前後方向に沿って移動自在な単一の主変速レバー２４、及び、直進を指令する直進指令位置及び旋回を指令する旋回操作用操作領域としての旋回指令範囲の全範囲にわたり移動操作自在な操作具としての単一の旋回レバー２６などが装備されている。そして、図３に示すように、主変速レバー２４の操作位置を検出する変速レバーセンサ２７と、旋回レバー２６の操作位置を検出する旋回レバーセンサ２８とが夫々設けられ、それらは共に回転式のポテンショメータにて構成されている。変速レバーセンサ２７及び旋回レバーセンサ２８の検出情報は後述する制御装置３１に入力される構成となっており、前記主変速レバー２４と変速レバーセンサ２７とにより車速指令手段が構成され、旋回レバー２６と旋回レバーセンサ２８とにより旋回指令手段が構成される。
【００３３】
又、走行用の一対の無段変速装置１１Ｒ、１１Ｌには、それらの出力回転速度を各別に検出する変速出力検出手段としての回転速度センサ４４、４５と、夫々の無段変速装置１１Ｒ、１１Ｌの変速位置、すなわち、一対の油圧シリンダ３３Ｒ、３３Ｌによる夫々のトラニオン軸２９の操作角度を検出する変速位置検出手段としての回転式のポテンショメータにて構成される変速位置センサ４６、４７とが夫々備えられている。尚、作業用の無段変速装置１２にも同様に回転速度センサ５１が設けられる。
【００３４】
そして、前記走行用操作機構３０の動作を制御する制御手段としてのマイクロコンピュータ利用の制御装置３１が備えられ、この制御装置３１は、主変速レバー２４にて指令される目標車速で車体を直進走行させるべく走行用操作機構３０を作動させる直進制御を実行するとともに、旋回レバー２６にて指令された旋回半径で旋回を行うべく走行用操作機構３０を作動させる旋回制御を実行する構成となっている。
【００３５】
前記直進制御について簡単に説明すると、旋回レバー２６が直進指令位置に操作されて直進が指令されている状態で、主変速レバー２４が操作可能範囲のほぼ中間に位置する中立位置に操作されると走行停止状態となり、中立位置から前進側へ揺動操作されるとそれに伴って前進側への走行速度が無段階で高速となる目標車速が指令され、中立位置から後進側へ操作されるとそれに伴って後進側への走行速度が無段階で高速となる目標車速が指令される。そして、左右一対の無段変速装置１１Ｒ、１１Ｌ夫々のトラニオン軸２９が目標車速に対応する目標変速位置から離れているときは、左右一対の無段変速装置１１Ｒ、１１Ｌ夫々のトラニオン軸２９を目標車速に対応する目標変速位置になるように走行用操作機構３０を作動させる。そして、いずれかの無段変速装置のトラニオン軸２９が目標変速位置に至ると、いずれか一方の無段変速装置はトラニオン軸２９が目標変速位置に維持されるように制御されるが、他方の無段変速装置はその出力回転速度が、前記一方の無段変速装置の出力回転速度と同じ速度になるように速度同期処理が行われる。
【００３６】
次に、旋回制御について説明すると、主変速レバー２４が操作されて所定速度で走行しているときに、旋回レバー２６が直進指令位置から左右いずれかの旋回指令範囲に揺動操作されると、前記直進指令位置から離れる側に操作されるほど旋回半径が小さくなるように旋回が指令され、その指令情報に基づいて制御装置３１が走行用操作機構３０を作動させるように構成されている。
説明を加えると、制御装置３１は、前記旋回制御として次のような処理を実行するように構成されている。つまり、一対の無段変速装置１１Ｒ、１１Ｌのうちの旋回中心から離れる側に位置する無段変速装置を基準側の無段変速装置として、その基準側の無段変速装置における変速用のトラニオン軸２９の変速位置が目標車速に対応する目標変速位置になるように走行用操作機構３０を作動させる変速位置調整処理、基準側の無段変速装置の出力回転速度を基準として、左右一対の無段変速装置１１Ｒ、１１Ｌの出力回転速度の速度比率が旋回レバー２６の操作位置にて指令される旋回半径に対応する速度比率となるように旋回中心側に位置する無段変速装置の目標回転速度を求める目標回転速度設定処理、及び、その目標回転速度設定処理にて求められる目標回転速度が零速でないときは、旋回中心側に位置する無段変速装置の出力回転速度が目標回転速度になるように回転速度センサの検出情報に基づいて走行用操作機構３０を作動させ、且つ、目標回転速度設定処理にて求められる目標回転速度が零速であるときは、旋回中心側に位置する無段変速装置における変速用のトラニオン軸２９の変速位置が零速に対応する目標変速位置になるように変速位置センサの検出情報に基づいて走行用操作機構３０を作動させる旋回用調整処理の夫々を実行するように構成されている。
【００３７】
以下、フローチャートに基づいて制御装置３１の旋回制御の処理動作について具体的に説明する。
図６に示すように、旋回レバー２６が直進指令位置から旋回指令範囲に揺動操作されて旋回が指令され、例えば右方向に旋回が指令されている場合には（ステップ１、２）、旋回中心に対して離れる側に位置する無段変速装置である左側の無段変速装置１１Ｌを基準側の無段変速装置として、その左側の無段変速装置１１Ｌにおけるトラニオン軸２９の変速位置が目標変速位置になるように走行用操作機構３０を作動させる変速位置調整処理を実行する（ステップ３）。
【００３８】
この変速位置調整処理について説明を加えると、図７に示すように、先ず、左側の無段変速装置１１Ｌにおけるトラニオン軸２９に対する目標変速位置を計算にて求める（ステップ３１）。このとき、主変速レバー２４にて指令されている目標車速に対応するトラニオン軸２９の変速位置を前記目標変速位置として設定するようになっている。次に、この目標変速位置と、変速位置センサ４７にて検出される現在のトラニオン軸２９の変速位置との偏差を求めて、その位置偏差が小さくなるように比例制御にて走行用操作機構３０を作動させてトラニオン軸２９の変速位置を変更調整する（ステップ３２、３３）。具体的には、走行用操作機構３０における給油用電磁弁３４Ａ及び各排油用電磁弁３４Ｂを切り換え制御して油圧シリンダ３３Ｒの作動を制御するのである。
【００３９】
上記したようにして変速位置調整が行われる左側の無段変速装置１１Ｌの出力回転速度を回転速度センサ４５にて検出して、左側の無段変速装置１１Ｌの出力回転速度と右側の無段変速装置１１Ｒの出力回転速度との速度比率が、旋回レバー２６の操作位置の変化に応じて変化する旋回レバーセンサ２８の検出情報に基づいて指令される旋回半径に対応する速度比率となるように右側の無段変速装置１１Ｒの目標回転速度を求める目標回転速度設定処理を実行する（ステップ４）。
【００４０】
図９に示すように、旋回レバー２６の操作位置に対する目標となる旋回半径に対応する左右の無段変速装置１１Ｒ、１１Ｌの速度比率の関係が予め設定されて記憶されており、この関係と、旋回レバー２６の操作位置による指令情報とに基づいて、右側の無段変速装置１１Ｒの目標回転速度を求めるのである。図９に示す関係について説明を加えると、この図は、旋回レバー２６の操作位置の変化に対して、基準側すなわち旋回中心に対して離れる側に位置する無段変速装置の出力回転速度Ｖを基準として、旋回中心側に位置する無段変速装置の速度比率の変化を示している。ステップ４では、右側の無段変速装置１１Ｒが旋回中心側に位置する無段変速装置であるから、この速度比率から右側の無段変速装置１１Ｒの目標回転速度を求めることになる。
【００４１】
この図から明らかなように、旋回レバー２６による直進指令位置からの移動量が大になるほど小さい旋回比率に対応する速度比率となり、直進指令位置から離れる方向への移動量が大になるほど、旋回レバーの操作位置の単位量あたりの変化に対する速度比率の変化量を大側に変化させる二次関数として設定されている。しかも、旋回レバー２６の移動量が最も大きい最大操作位置に操作されたときの速度比率が互いに異なる形態の複数（図９に示す例では４種類）の旋回モードが選択可能に構成されている。そして、旋回モードを切り換えるためのモード切換スイッチ４２が設けられており、このモード切換スイッチ４２による切換指令が制御装置３１に与えられて、制御装置３１は、その切換指令に基づいていずれの特性を利用して目標回転速度を求めるかを決定するようになっている。
【００４２】
図９に示す４種類の旋回モードについて説明すると、旋回レバー２６が最大操作位置にまで操作されたときに、旋回中心側の無段変速装置の出力回転速度が反対側の無段変速装置の出力回転速度Ｖの約１／３の速度にまで減速される緩旋回モード（Ｌ１）、旋回中心側の無段変速装置の出力回転速度が零となるまで減速される信地旋回モード（Ｌ２）、旋回中心側の無段変速装置の出力回転速度が反対側の無段変速装置の駆動回転方向とは逆回転方向で反対側の無段変速装置の出力回転速度Ｖの約１／３の速度になる低速スピン旋回モード（Ｌ３）、旋回中心側の無段変速装置の出力回転速度が反対側の無段変速装置の駆動回転方向とは逆回転方向で反対側の無段変速装置の出力回転速度Ｖと同程度の速度になる高速スピン旋回モード（Ｌ４）が夫々設定されている。
【００４３】
前記緩旋回モードでは、旋回レバー２６がどのような操作位置にあっても、旋回中心側の無段変速装置に対する目標回転速度は零速になることはないが、前記信地旋回モードでは、旋回レバー２６による直進指令位置からの移動量が大になるほど漸次低速となり、且つ、旋回レバー２６が旋回指令範囲の最大操作位置にまで操作されて最も小さい旋回半径が指令されたときに零速となる形態で目標回転速度を求めることになる。そして、低速スピン旋回モードや高速スピン旋回モードでは、旋回レバー２６による直進指令位置からの移動量が大になるほど漸次低速にして零速とし、且つ、その後において逆回転状態で漸次高速にする形態で目標回転速度を求めることになる。
【００４４】
上記したようにして目標回転速度が求められると、次に、右側の無段変速装置について旋回用調整処理を実行する（ステップ５）。この旋回用調整処理は、図８に示すように、上述したような４種類の旋回モードのうちモード切換スイッチ４２にて信地旋回モード以外の旋回モードが選択されており、且つ、求められる目標回転速度が零速でない場合（ステップ５０、５１）、及び、信地旋回モードが選択されていても旋回レバー２６が最大操作位置に操作されていない場合（ステップ５０、５２）には、目標回転速度と現在の右側の無段変速装置１１Ｒの出力回転速度との偏差を求めて、その偏差が小さくなるように、つまり、右側の無段変速装置１１Ｒの出力回転速度が前記目標回転速度になるように、比例積分（ＰＩ）制御によって走行用操作機構３０を作動させる回転速度調整処理を実行する（ステップ５３）。具体的には、走行用操作機構３０における給油用電磁弁３４Ａ及び各排油用電磁弁３４Ｂを切り換え制御して出力回転速度が目標回転速度になるようにトラニオン軸２９の変速位置を変更調整する。このようにして、左右の走行装置１Ｒ、１Ｌが前記速度比率にて回転駆動されて、旋回レバー２６にて指令された旋回半径にて車体が旋回走行するのである。
【００４５】
そして、信地旋回モード以外の旋回モードが選択されており、且つ、求められる目標回転速度が零速である場合（ステップ５０、５１）、及び、信地旋回モードが選択されていて旋回レバー２６が最大操作位置に操作されている場合（ステップ５０、５２）には、右側の無段変速装置におけるトラニオン軸２９の変速位置が零速に対応する目標変速位置になるように変速位置センサ４６の検出情報に基づいて走行用操作機構３０を作動させる（ステップ５４）。このようにして、旋回中心側に位置する右側の無段変速装置１１Ｒを零速に維持した状態で適正に旋回を行うことができる。
【００４６】
ステップ２で旋回方向として左方向が指令されている場合には、制御される対象が左右反対になるが、右側の無段変速装置１１Ｒを基準側の無段変速装置としてステップ３〜５と同様な変速位置調整処理、目標回転速度設定処理、及び、旋回用調整処理の夫々を実行することになる（ステップ６、７、８）。
【００４７】
〔別実施形態〕
次に、別実施形態を列記する。
【００４８】
（１）上記実施形態では、旋回レバー２６の操作位置に対する目標となる旋回半径に対応する左右の無段変速装置１１Ｒ、１１Ｌの速度比率の関係として、４種類のモードが設定され、選択して使用する構成としたが、このような構成にかぎらず、目標回転速度として零速が存在する１つのモードのみで制御する構成としてもよい。例えば、前記信地旋回モード、前記低速スピン旋回モード又は前記高速スピン旋回モードのうちのいずれか１つの旋回モードを備える構成としてもよい。そのとき、前記旋回用調整処理としては、図８に示すようなフローチャートに代えて次のように構成するものでもよい。
【００４９】
例えば、前記信地旋回モードのみを備える構成であれば、図８のステップ５０及びステップ５１の判断処理は省略して、ステップ５２の旋回レバーの最大操作位置にあるか否かの判断に基づいて、ステップ５３の回転速度調整を実行するか、ステップ５４の零速に対応する変速位置調整を実行するかを判別するようにしてもよい。
【００５０】
又、前記低速スピン旋回モード又は前記高速スピン旋回モードのうちのいずれかのみを備える構成であれば、図８のステップ５０及びステップ５２の判断処理は省略して、ステップ５１の目標回転速度が零速であるか否かの判断に基づいて、ステップ５３の回転速度調整を実行するか、ステップ５４の零速に対応する変速位置調整を実行するかを判別するようにしてもよい。
【００５１】
（２）上記実施形態では、旋回レバー２６の操作位置に対する目標となる旋回半径に対応する左右の無段変速装置１１Ｒ、１１Ｌの速度比率の関係として、直進指令位置から離れる方向への移動量が大になるほど、旋回レバーの操作位置の単位量あたりの変化に対する旋回半径の変化量を大側に変化させる二次関数として設定されるものを例示したが、このような構成に限るものではなく、移動量が大になるほど旋回半径が小さくなるものであればよく変化特性は限定されない。例えば、直線的に変化するものや傾きの異なる複数の直線を折れ線状態に繋いだもの等各種の形態で実施することができる。
【００５２】
（３）上記実施形態では、旋回指令手段として、左右の揺動操作自在な操作具としての旋回レバーと、その操作位置を検出するポテンショメータ式の旋回レバーセンサとを備える構成としたが、このような構成に限らず、例えば、指令する旋回半径が互いに異なる複数のスイッチで構成したり、スイッチを押し操作する時間で旋回半径を異ならせるように指令する構成等、各種の形態で実施してもよい。又、車速指令手段も旋回指令手段と同様に、複数のスイッチで構成するなど各種の形態で実施してもよい。
【００５３】
（４）上記実施形態では、無段変速装置のトラニオン軸を操作するアクチュエータとして、油圧シリンダを例示したが、油圧モータや電動モータ等他のアクチュエータを用いてもよい。
【００５４】
（５）上記実施形態では、一対の無段変速装置として、静油圧式無段変速装置を用いたが、このような構成に代えて、例えば、テーパコーン型の無段変速装置等の他の無段変速装置を用いてもよい。
【００５５】
（６）上記実施形態では、作業車としてコンバインを例示したが、本発明はコンバインに限らず、人参収穫機や大根収穫機など他の農作業車でもよく、又、農作業車に限らず建設機械等の作業車でもよい。
【図面の簡単な説明】
【図１】コンバインの全体側面図
【図２】伝動構造を示す概略縦断背面図
【図３】操作構造の構成を示す概略図
【図４】変速位置と変速出力との関係を示す図
【図５】主変速レバー操作位置と目標車速との関係を示す図
【図６】制御動作のフローチャート
【図７】制御動作のフローチャート
【図８】制御動作のフローチャート
【図９】旋回レバーの位置と速度比率との関係を示す図
【符号の説明】
１Ｒ、１Ｌ走行装置
１１Ｒ、１１Ｌ無段変速装置
２４、２７車速指令手段
２６、２８旋回指令手段
２９被操作体
３０変速操作手段
３１制御手段
４４、４５変速出力検出手段
４６、４７変速位置検出手段[0001]
BACKGROUND OF THE INVENTION
The present invention provides a traveling speed of a pair of left and right traveling devices. Change A pair of speedless continuously variable transmissions, a speed change operation means that can freely shift the pair of continuously variable transmissions individually, and a command for direct advance and turn, and a turn radius when turning. The present invention relates to a turning control device for a work vehicle, which is provided with turning command means and control means for executing turning control for operating the speed change operation means to perform straight advancement and turning based on command information of the turning command means.
[0002]
[Prior art]
The traveling control device for a work vehicle having the above configuration is applied to a work vehicle such as a combine, for example, and conventionally has the following configuration.
In other words, a hydrostatic continuously variable transmission is used as the pair of continuously variable transmissions, a pair of electric motors are provided as shift operation means, and the output rotation speed of each of the pair of continuously variable transmissions is a pair of rotation sensors. And a pair of continuously variable transmissions are operated by each electric motor so that the detected values of these rotation sensors become the target output rotational speeds. There is a steering clutch capable of turning power transmission on and off the transmission lower side of the device and a steering brake capable of braking each traveling device, and the turn control includes a configuration for executing the following processing. . That is, as the turning mode, there are a gentle turning mode, a brake turning mode, and a spin turning mode, and in the gentle turning mode, the amount of movement of the power steering lever as the turning command means in the direction away from the straight advance command position becomes large and small. As the turning radius is commanded, the continuously variable transmission on the turning center side is steplessly maintained while maintaining the output rotational speed of the continuously variable transmission on the side away from the turning center of the pair of left and right continuously variable transmissions at a predetermined speed. There is a configuration in which the operation of the speed change operation means is controlled so as to reduce the turning radius when turning by changing the ratio of the rotational speeds of the pair of continuously variable transmissions in the form of decelerating. In the brake turning mode, when the turning angle of the power steering lever becomes large, the steering device is turned with the steering clutch disengaged and the steering brake is operated with respect to the traveling device on the turning center side. In addition to turning the steering clutch and actuating the steering brake, when the operating angle for turning the power steering lever increases, the traveling device on the turning center side switches to a state of reverse rotation (for example, , See Patent Document 1).
[0003]
[Patent Document 1]
JP-A-8-172871 (pages 3-5, FIGS. 4 and 6)
[0004]
[Problems to be solved by the invention]
In the above conventional configuration, when turning in the slow turning mode, the output rotational speed of the continuously variable transmission on the side far from the turning center of the pair of left and right continuously variable transmissions is maintained at the set speed, and the turning center side is maintained. The speed of the pair of continuously variable transmissions is changed so that the output rotational speed of each of the pair of continuously variable transmissions becomes the target output rotational speed. The operation means is configured to operate, and there is a disadvantage that the following inconvenience occurs when zero speed is commanded as the target rotation speed.
[0005]
In other words, in the above configuration, even when zero speed is commanded as the target rotational speed, the output rotational speed of the continuously variable transmission on the turning center side detected by the rotation sensor is the target rotational speed, that is, zero. The speed change target is adjusted to a position corresponding to zero speed by an electric motor as a speed change operation means so that the speed is increased. However, a work vehicle such as a combiner often travels on uneven terrain such as a farm field, and the traveling load on the traveling device becomes large on such uneven terrain. Even when the vehicle is turning at a high speed, the traveling device on the turning center side may be rotated in the same direction as the traveling direction of the opposite traveling device due to friction with the ground.
[0006]
When such follow-up occurs, the detected value of the rotation sensor is rotating at a predetermined rotation speed instead of zero even though the shift target is adjusted to a position corresponding to zero speed. It will be detected by mistake as a state. Then, the gear to be operated is further decelerated from the position corresponding to zero speed so that the object to be shifted is decelerated by a predetermined rotational speed from that state. The speed change operation is performed to the operation position corresponding to the reverse rotation direction in which the rotation direction is reversed.
[0007]
However, when it is detected that the operating object for shifting is operated to the operating position in the reverse direction, the control means determines that the speed change output of the continuously variable transmission is rotation in the reverse direction. Then, this time, in order to set the rotation in the reverse rotation direction to zero speed, control is performed to immediately return the speed change target to the original position in the normal rotation direction. In addition, as described above, it is repeatedly executed to operate the speed change target object further than the position corresponding to the zero speed so as to decelerate from the state by a predetermined rotational speed. become. As a result, the object to be shifted is alternately switched between the forward rotation state and the reverse rotation state in the vicinity of the neutral position, and the output rotation speed does not converge to zero speed, and the following rotation state continues. Therefore, there is a disadvantage that proper turning cannot be performed in a state where the traveling device on the turning center side is set to zero speed.
[0008]
By the way, in the above-described conventional configuration, the turning mode is switched to the brake turning mode, the steering clutch for the traveling device on the turning center side is turned off, and the steering brake is operated, so that the traveling device on the turning center side is reduced to zero. In such a configuration, in addition to the operation of the pair of left and right continuously variable transmissions, not only the turning center side by a mechanical braking means such as a steering brake is used. There is a disadvantage that the braking operation for the traveling device must be executed and the configuration becomes complicated.
[0009]
The present invention has been made paying attention to this point, and its purpose is to make the traveling device on the turning center side zero speed without complicating the configuration of performing a braking operation by mechanical braking means. It is in the point which provides the turning control apparatus of the working vehicle which can perform an appropriate turning in the state where it was.
[0010]
[Means for Solving the Problems]
The turning control device for a work vehicle according to claim 1 is a traveling speed of a pair of left and right traveling devices. Change A pair of speedless continuously variable transmissions, a speed change operation means that can freely shift the pair of continuously variable transmissions individually, and a command for direct advance and turn, and a turn radius when turning. A turn command means; and a control means for executing turn control for operating the speed change operation means to perform straight advance and turn based on command information of the turn command means, wherein A pair of shift position detecting means for separately detecting the shift position of the operating body for shifting in each of the stepped transmissions, and a pair of shift output detecting means for separately detecting the output rotational speeds of the pair of continuously variable transmissions The control means, as the turning control, is a pair of left and right continuously variable continuously with reference to the output rotational speed of the continuously variable transmission located on the side away from the turning center detected by the shift output detecting means. Strange Target rotational speed setting for determining the target rotational speed of the continuously variable transmission located on the turning center side so that the speed ratio of the output rotational speed of the apparatus becomes a speed ratio corresponding to the turning radius commanded by the turning command means When the target rotational speed obtained in the processing and the target rotational speed setting process is not zero speed, the output rotational speed of the continuously variable transmission located on the turning center side is set to the target rotational speed. When the speed change operation means is operated based on the detection information of the speed change output detection means and the target rotational speed obtained in the target rotational speed setting process is zero speed, there is no position located on the turning center side. The shift operation means is operated based on the detection information of the shift position detection means so that the shift position of the operating object for shifting in the step transmission is a target shift position corresponding to zero speed. Characterized in that it is configured to perform each of the times for the adjustment process.
[0011]
That is, based on the output rotational speed of the continuously variable transmission located on the side away from the turning center, the speed ratio of the output rotational speed of the pair of left and right continuously variable transmissions corresponds to the turning radius commanded by the turning command means. The target rotational speed of the continuously variable transmission located on the turning center side is calculated so that the speed ratio is obtained. If the target rotational speed is not zero, the output rotational speed of the continuously variable transmission located on the turning center side is the target rotational speed. The shift operation means is operated so that the rotation speed is reached. Thus, the pair of left and right traveling devices travels at a speed ratio corresponding to the turning radius commanded by the turning command means, so that appropriate turning is performed.
[0012]
When the target rotational speed is zero, the shift position is detected so that the shift position of the operating object for shifting in the continuously variable transmission located on the turning center side becomes the target shift position corresponding to the zero speed. Since the speed change operation means is operated based on the detection information of the means, the speed change position of the operating object for speed change in the continuously variable transmission on the turning center side is held at the target speed change position corresponding to zero speed. Even if the speed change state does not change and the braking operation by the mechanical braking means is not performed, the traveling device located on the turning center side can maintain the state of zero speed, and the proper turning can be performed. It becomes possible.
[0013]
Therefore, it is possible to turn the work vehicle so that it is possible to perform an appropriate turn with the traveling device on the turning center side set to zero speed without complicating the configuration of performing a braking operation by mechanical braking means. A control device can be provided.
[0014]
According to a second aspect of the present invention, there is provided the work vehicle turning control device according to the first aspect, further comprising vehicle speed command means for commanding a target vehicle speed when the straight command is commanded by the turning command means. In the turning control, the shift position detecting means is arranged so that the shift position of the operating body for shifting in the continuously variable transmission located on the side away from the turning center becomes a target shift position corresponding to the target vehicle speed. The shift operation means is configured to operate based on detection information.
[0015]
That is, the speed change operation means is set so that the speed change position of the operated object for speed change in the continuously variable transmission located on the side away from the turning center becomes the target speed change position corresponding to the target vehicle speed commanded by the vehicle speed command means. It is activated. As described above, the continuously variable transmission on the speed ratio reference side is controlled so that the speed change position of the operated body becomes the target speed change position. For example, the output rotation speed changes due to a change in travel load or the like. Even so, the target shift position relative to the shift position of the operated body does not change. Then, the output rotational speed of the continuously variable transmission on the opposite side is a speed so as to be a speed ratio corresponding to the turning radius commanded by the turning command means on the basis of the output rotational speed of the reference continuously variable transmission. Adjusted. In other words, when the engine rotational speed fluctuates due to fluctuations in travel load, etc., the output rotational speed of the pair of left and right continuously variable transmissions changes, but the pair of left and right continuously variable transmissions have substantially the same speed. The ratio changes while maintaining the ratio, and it is possible to appropriately turn and travel with the turning radius commanded by the turning command means with little error.
[0016]
According to a third aspect of the present invention, there is provided the turning control device for a work vehicle according to the first or second aspect, wherein the turning command means can be moved and operated over the entire range of the straight running command position for commanding straight travel and the operation area for turning operation for commanding turning. The control means is configured to command a turning radius that is so small that the operation tool is moved in a direction away from the rectilinear command position in the operation area for turning operation. As the setting process, the turning center is gradually reduced as the turning radius commanded by the turning command means decreases, and is set to zero speed when the smallest turning radius is commanded by the turning command means. It is comprised so that the process which calculates | requires the target rotational speed of the continuously variable transmission located in the side may be performed.
[0017]
That is, the smaller the turning radius is commanded as the operating tool of the turning command means moves away from the rectilinear command position in the turning operation region, the lower the turning radius commanded, the lower the speed gradually. Then, the target rotational speed of the continuously variable transmission located on the turning center side is obtained, and when the smallest turning radius is commanded, zero speed is commanded as the target rotational speed.
[0018]
Accordingly, when the smallest turning radius is commanded by operating to the maximum operating position, the speed change operating means is operated so that the speed change position of the speed change target object becomes the target speed change position corresponding to zero speed. It is possible to turn.
[0019]
According to a fourth aspect of the present invention, there is provided the turning control device for a work vehicle according to the first or second aspect, wherein the turning command means can be moved and operated over the entire range of the straight advance command position for commanding straight travel and the operation area for the swing operation for commanding the turn. An operating tool, and is configured to command a turning radius that is so small that the operating tool is moved in a direction away from the rectilinear command position in the turning operation operation region, and the control means is configured to set the target rotational speed. As a process, the continuously variable transmission located on the side of the turning center is configured so as to gradually decrease to zero speed as the turning radius commanded by the turning command means becomes smaller and then gradually increase in the reverse rotation state. It is comprised so that the process which calculates | requires target rotational speed may be performed.
[0020]
That is, a smaller turning radius is commanded as the operating tool of the turning command means is moved away from the rectilinear command position in the operation area for turning operation, but the speed becomes zero as the commanded turning radius becomes smaller. The target rotational speed of the continuously variable transmission located on the turning center side is obtained in such a manner that the speed gradually decreases and then gradually increases in the reverse rotation state. In other words, when the operating tool is moved away from the rectilinear command position in the turning operation area, the target rotational speed of the continuously variable transmission located on the turning center side gradually decreases, and the operating tool is moved to the turning operation area. When operating to a predetermined position in the middle, the target rotational speed becomes zero speed. When the operating tool is further moved, the target rotational speed becomes gradually higher in the reverse rotation state, and the turning radius is further increased as compared with the case where the traveling device located on the turning center side is in the reverse rotation state and turns at zero speed. It is possible to make a small turn with a small.
[0021]
Therefore, when the operating tool is operated to a predetermined position in the middle of the operation area for turning operation and the target rotational speed becomes zero speed, the speed change position of the operating object for speed change becomes the target speed change position corresponding to the zero speed. Since the speed change operating means is operated, proper turning is performed even in such a case.
[0022]
A turning control device for a work vehicle according to a fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, each of the pair of continuously variable transmissions is constituted by a hydrostatic continuously variable transmission. To do.
[0023]
The hydrostatic continuously variable transmission can be operated in a stepless manner in both the forward direction and the reverse direction by operating an object to be shifted. There is a neutral range where the speed becomes zero between the speed change operation range in the reverse direction and the gear shift output can be made zero speed by operating the object to be shifted to the neutral range.
Therefore, smooth turning traveling can be performed by gradually changing the turning radius by steplessly shifting the pair of left and right traveling devices in the forward direction and the backward direction in a state including zero speed separately.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a case where an embodiment of a turning control device for a work vehicle according to the present invention is applied to a combine as an example of a work vehicle will be described with reference to the drawings.
[0025]
FIG. 1 shows an overall side view of a combine that is an example of a work vehicle. The combine is located in front of a traveling machine body 2 that is driven by a pair of left and right crawler type traveling devices 1R and 1L that are an example of a traveling device. The cutting and conveying device 3 that cuts the planted cereal and conveys it to the rear is connected to the section so that it can be raised and lowered, and the traveling machine body 2 receives the chopped cereal from the chopping and conveying device 3 and performs threshing processing and sorting processing. The threshing device 4 to be executed and the grain tank 5 for storing the grain from the threshing device 4 are mounted, and the boarding operation unit 6 is formed at a location in front of the grain tank 5.
[0026]
As shown in FIG. 2, this combine transmits power from the engine 7 to the input shaft 10 of the transmission case 9 via the belt tension type main clutch 8, and a pair of traveling non-loads from the input shaft 10. Distributing and transmitting to the step transmissions 11R and 11L, and transmitting the power after shifting by the one continuously variable transmission 11L for traveling to the left crawler traveling device 1L via the left gear-type sub-transmission device 13L, A driving mechanism is configured to transmit power after shifting by the other continuously variable transmission 11R for traveling to the right crawler traveling device 1R via the right gear-type auxiliary transmission 13R. is doing. On the other hand, the power from the engine 7 is also supplied to the continuously variable transmission 12 for work, and the power after shifting by the continuously variable transmission 12 for work is transferred to the cutting and conveying device via the belt tension type cutting clutch 14. The transmission mechanism for the cutting operation is configured so as to be transmitted to 3. The left and right gear-type sub-transmission devices 13R and 13L are configured to be able to switch the power after shifting of the continuously variable transmission devices 11R and 11L to high and low two stages. The boarding operation unit 6 is provided with a single auxiliary transmission lever 25 that can swing in the front-rear direction. The auxiliary transmission lever 25 is connected to a gear-type auxiliary transmission mechanism 13R, via a linkage mechanism (not shown). 13L is linked, and the power after shifting by the continuously variable transmissions 11R, 11L for traveling can be shifted to two levels of high and low by operating the auxiliary transmission lever 25.
[0027]
Each of the continuously variable transmissions 11R and 11L for traveling includes an axial plunger type variable displacement piston pump 19 and a piston motor 20, and is configured as a hydrostatic continuously variable transmission. Similarly, the transmission 12 includes an axial plunger type variable displacement piston pump 21 and a piston motor 22 and is configured as a hydrostatic continuously variable transmission, and advances in the traveling direction of the left and right traveling devices 1R and 1L. The direction and reverse direction can be switched and the traveling speed can be changed steplessly.
[0028]
Then, as shown in FIG. 3, a hydraulic travel operation mechanism 30 as a shift operation means for shifting the travel continuously variable transmissions 11R and 11L separately and a working continuously variable transmission 12 are provided. A hydraulic work operation mechanism 36 that performs a speed change operation is provided. The travel operation mechanism 30 includes a pair of double-acting hydraulic cylinders 33R and 33L that are interlocked and connected to a trunnion shaft 29 (an example of an operated body) in each of the continuously variable transmissions 11R and 11L for travel, A pair of two-position switching type oil supply electromagnetics that can be switched between a state in which hydraulic oil is supplied to a pair of oil chambers and a state in which the supply is stopped corresponding to operations in the forward and reverse directions with respect to the respective hydraulic cylinders 33R and 33L. It comprises a valve 34A and a pair of two-position switching type oil discharge solenoid valve 34B that can be switched between a state in which the hydraulic oil is discharged from the pair of oil chambers and a state in which the discharge is stopped. Each of the hydraulic cylinders 33R and 33L is configured to be urged to return to the neutral position by the urging force of an internally mounted spring.
[0029]
Similarly, the work operation mechanism 36 is linked to the trunnion shaft 37 of the work continuously variable transmission 12 and is double-actuated so as to be returned to the neutral position by the biasing force of the internal spring. And a pair of two-position switching type oil supply that can be switched between a state in which hydraulic oil is supplied to a pair of oil chambers corresponding to respective operations in the forward and reverse directions with respect to the hydraulic cylinder 40 and a state in which the supply is stopped. 41A, and a pair of two-position switching type oil discharge solenoid valve 41B that can be switched between a state in which hydraulic oil is discharged from the pair of oil chambers and a state in which the discharge is stopped. .
[0030]
Each of the solenoid valves 34A, 41A for refueling is configured to move and urge the spool to a refueling stop state by a biasing force of the spring, and operates to move the spool against the biasing force of the spring by the electromagnetic force of the solenoid. Each of the solenoid valves 34B and 41B for draining oil is configured to be urged to move the spool to a discharged state by a biasing force of a spring. The structure is switched to a state in which the discharge of the hydraulic oil is stopped by moving the spool against the urging force of the spring by the electromagnetic force of the solenoid.
[0031]
The outline of the speed change operation of the continuously variable transmissions 11R and 11L as described above will be described. As shown in FIG. 4, if the speed change position of the trunnion shaft 29 is in the neutral range, the speed change output (travel speed) becomes zero. When the shift position of the trunnion shaft 29 is rotated in a predetermined direction from the neutral region, the traveling speed in the forward direction is increased steplessly, and the trunnion shaft 29 rotates in the direction opposite to the predetermined direction from the neutral region. When the vehicle is operated, the traveling speed in the reverse direction is increased steplessly.
[0032]
The boarding operation unit 6 is commanded to a single main transmission lever 24 that is movable along the longitudinal direction of the vehicle body within a predetermined operation range including a neutral position as a stop command position for commanding stop of traveling, and to go straight. A single turning lever 26 as an operation tool that can be moved and operated over the entire range of the turning command range as a turning operation range for instructing a straight command position and turning is provided. As shown in FIG. 3, a shift lever sensor 27 for detecting the operation position of the main shift lever 24 and a swing lever sensor 28 for detecting the operation position of the swing lever 26 are provided, both of which are rotary. It consists of a potentiometer. Information detected by the shift lever sensor 27 and the turning lever sensor 28 is input to a control device 31 to be described later. The main speed change lever 24 and the speed change lever sensor 27 constitute a vehicle speed command means. The turning lever sensor 28 constitutes a turning command means.
[0033]
Further, the pair of continuously variable transmissions 11R and 11L for traveling include rotational speed sensors 44 and 45 as shift output detecting means for detecting their output rotational speeds individually, and respective continuously variable transmissions 11R and 11L. Shift position sensors 46 and 47 each comprising a rotary potentiometer as a shift position detecting means for detecting an operation angle of each trunnion shaft 29 by a pair of hydraulic cylinders 33R and 33L. It has been. The working continuously variable transmission 12 is similarly provided with a rotational speed sensor 51.
[0034]
A control device 31 using a microcomputer is provided as a control means for controlling the operation of the travel operation mechanism 30, and this control device 31 travels straight through the vehicle body at a target vehicle speed commanded by the main transmission lever 24. In addition to executing straight-ahead control for operating the travel operation mechanism 30 in order to perform the turn, the turning control for operating the travel operation mechanism 30 to perform the turn with the turning radius commanded by the turning lever 26 is performed. .
[0035]
Briefly describing the straight-ahead control, when the main transmission lever 24 is operated to a neutral position that is located approximately in the middle of the operable range in a state in which the turning lever 26 is operated to the straight-ahead command position and a straight-ahead command is issued. When the vehicle is in the travel stop state and is swung from the neutral position to the forward side, a target vehicle speed is commanded to increase the traveling speed to the forward side steplessly, and when it is operated from the neutral position to the reverse side, Along with this, a target vehicle speed at which the traveling speed toward the reverse side becomes a stepless high speed is commanded. When the trunnion shafts 29 of the pair of left and right continuously variable transmissions 11R and 11L are away from the target shift position corresponding to the target vehicle speed, the trunnion shafts 29 of the pair of left and right continuously variable transmissions 11R and 11L are targeted. The travel operation mechanism 30 is actuated so as to reach the target shift position corresponding to the vehicle speed. When the trunnion shaft 29 of any continuously variable transmission reaches the target shift position, one of the continuously variable transmissions is controlled so that the trunnion shaft 29 is maintained at the target shift position. The continuously variable transmission is subjected to speed synchronization processing so that the output rotational speed thereof is the same as the output rotational speed of the one continuously variable transmission.
[0036]
Next, the turning control will be described. When the turning lever 26 is swung from the rectilinear command position to either the left or right turning command range when the main transmission lever 24 is operated and the vehicle is traveling at a predetermined speed, The turning is commanded so that the turning radius becomes smaller as the operation is further away from the straight command position, and the control device 31 is configured to operate the travel operation mechanism 30 based on the command information.
If it demonstrates, the control apparatus 31 will be comprised so that the following processes may be performed as said turning control. That is, the continuously variable transmission located on the side away from the turning center of the pair of continuously variable transmissions 11R and 11L is used as a reference continuously variable transmission, and a trunnion shaft for shifting in the reference continuously variable transmission is used. A shift position adjustment process for operating the travel operation mechanism 30 so that the 29 shift positions become a target shift position corresponding to the target vehicle speed, and a pair of left and right continuously variable steps based on the output rotational speed of the continuously variable transmission on the reference side The target rotational speed of the continuously variable transmission located on the turning center side is set so that the speed ratio of the output rotational speeds of the transmissions 11R and 11L becomes a speed ratio corresponding to the turning radius commanded at the operation position of the turning lever 26. When the target rotational speed setting process to be obtained and the target rotational speed obtained by the target rotational speed setting process are not zero, the output rotational speed of the continuously variable transmission located on the turning center side is the target. When the travel operation mechanism 30 is operated based on the detection information of the rotation speed sensor so that the rotation speed is reached, and the target rotation speed obtained in the target rotation speed setting process is zero speed, Turning adjustment processing for operating the travel operation mechanism 30 based on the detection information of the shift position sensor so that the shift position of the trunnion shaft 29 for shifting in the continuously variable transmission is located at the target shift position corresponding to zero speed. Each of which is configured to execute.
[0037]
The processing operation of the turning control of the control device 31 will be specifically described below based on the flowchart.
As shown in FIG. 6, when the turning lever 26 is swung from the straight command position to the turn command range and a turn is commanded, for example, a turn is commanded to the right (steps 1 and 2), the turn The left continuously variable transmission 11L, which is a continuously variable transmission located on the side away from the center, is used as the reference continuously variable transmission, and the shift position of the trunnion shaft 29 in the left continuously variable transmission 11L is the target shift. A shift position adjustment process for operating the travel operation mechanism 30 so as to be in the position is executed (step 3).
[0038]
If this shift position adjustment process is described, as shown in FIG. 7, first, a target shift position for the trunnion shaft 29 in the left continuously variable transmission 11L is calculated (step 31). At this time, the shift position of the trunnion shaft 29 corresponding to the target vehicle speed commanded by the main shift lever 24 is set as the target shift position. Next, a deviation between the target shift position and the current shift position of the trunnion shaft 29 detected by the shift position sensor 47 is obtained, and the travel operation mechanism 30 is controlled by proportional control so that the position deviation is reduced. Is operated to change and adjust the shift position of the trunnion shaft 29 (steps 32 and 33). Specifically, the operation of the hydraulic cylinder 33R is controlled by switching control of the oil supply solenoid valve 34A and each oil discharge solenoid valve 34B in the travel operation mechanism 30.
[0039]
The rotational speed sensor 45 detects the output rotational speed of the left continuously variable transmission 11L where the shift position adjustment is performed as described above, and the output rotational speed of the left continuously variable transmission 11L and the right continuously variable transmission. The right side so that the speed ratio with the output rotation speed of the device 11R becomes the speed ratio corresponding to the turning radius commanded based on the detection information of the turning lever sensor 28 that changes according to the change in the operation position of the turning lever 26. The target rotational speed setting process for obtaining the target rotational speed of the continuously variable transmission 11R is executed (step 4).
[0040]
As shown in FIG. 9, the relationship between the speed ratios of the left and right continuously variable transmissions 11R and 11L corresponding to the target turning radius with respect to the operation position of the turning lever 26 is preset and stored. Based on the command information based on the operation position of the turning lever 26, the target rotational speed of the right continuously variable transmission 11R is obtained. When the relationship shown in FIG. 9 is added, this figure shows the output rotational speed V of the continuously variable transmission located on the reference side, that is, on the side away from the turning center, with respect to the change in the operation position of the turning lever 26. As a reference, the change in the speed ratio of the continuously variable transmission located on the turning center side is shown. In step 4, since the right continuously variable transmission 11R is a continuously variable transmission located on the turning center side, the target rotational speed of the right continuously variable transmission 11R is obtained from this speed ratio.
[0041]
As is apparent from this figure, the greater the amount of movement from the rectilinear command position by the turning lever 26, the smaller the speed ratio corresponding to the turning ratio, and the greater the amount of movement in the direction away from the rectilinear command position, the greater the turning lever. It is set as a quadratic function that changes the change amount of the speed ratio with respect to the change per unit amount of the operation position. In addition, a plurality of (four types in the example shown in FIG. 9) swivel modes having different speed ratios when operated to the maximum operation position where the movement amount of the swivel lever 26 is the largest are selectable. A mode changeover switch 42 for switching the turning mode is provided. A change command by the mode changeover switch 42 is given to the control device 31, and the control device 31 has any characteristic based on the change command. It is determined whether to obtain the target rotational speed by using it.
[0042]
The four types of turning modes shown in FIG. 9 will be described. When the turning lever 26 is operated to the maximum operating position, the output rotational speed of the continuously variable transmission on the turning center side is the output of the continuously variable transmission on the opposite side. A slow turning mode (L1) in which the speed is reduced to about 1/3 of the rotational speed V, a faithful turning mode (L2) in which the output speed of the continuously variable transmission on the turning center side is reduced to zero, The output rotational speed of the continuously variable transmission on the turning center side is opposite to the driving rotational direction of the continuously variable transmission on the opposite side, and is approximately 1/3 of the output rotational speed V of the opposite continuously variable transmission. Low-speed spin turning mode (L3), the output rotational speed of the continuously variable transmission on the opposite side is opposite to the drive rotational direction of the continuously variable transmission on the opposite side. High-speed spin rotation mode (L4 There are respectively set.
[0043]
In the slow turning mode, the target rotational speed for the continuously variable transmission on the turning center side does not become zero no matter what the operation position of the turning lever 26 is. As the amount of movement from the rectilinear command position by the lever 26 increases, the speed gradually decreases, and when the turning lever 26 is operated to the maximum operating position in the turning command range and the smallest turning radius is commanded, the speed becomes zero speed. The target rotational speed is obtained in the form. In the low-speed spin turning mode and the high-speed spin turning mode, the speed is gradually reduced to zero speed as the amount of movement from the rectilinear command position by the turning lever 26 is increased, and then gradually increased in the reverse rotation state. The target rotation speed is obtained.
[0044]
When the target rotational speed is obtained as described above, the turning adjustment process is next executed for the right continuously variable transmission (step 5). As shown in FIG. 8, in this turning adjustment process, a turning mode other than the belief turning mode is selected by the mode changeover switch 42 among the four kinds of turning modes as described above, and the desired target is obtained. When the rotation speed is not zero (steps 50 and 51), and when the pivoting lever 26 is not operated to the maximum operation position even when the pivot turn mode is selected (steps 50 and 52), the target rotation is performed. The deviation between the current speed and the output rotational speed of the current continuously variable transmission 11R is obtained so that the deviation becomes smaller, that is, the output rotational speed of the right continuously variable transmission 11R becomes the target rotational speed. As described above, a rotation speed adjustment process for operating the travel operation mechanism 30 by proportional integral (PI) control is executed (step 53). Specifically, the shift position of the trunnion shaft 29 is changed and adjusted so that the output rotation speed becomes the target rotation speed by switching control of the oil supply solenoid valve 34A and each oil discharge solenoid valve 34B in the traveling operation mechanism 30. . In this way, the left and right traveling devices 1R, 1L are rotationally driven at the speed ratio, and the vehicle body turns with the turning radius commanded by the turning lever 26.
[0045]
Then, when a turning mode other than the belief turning mode is selected, and the required target rotational speed is zero speed (steps 50 and 51), and the belief turning mode is selected and the turning lever 26 is turned on. Is operated to the maximum operating position (steps 50 and 52), the shift position sensor 46 is set so that the shift position of the trunnion shaft 29 in the right continuously variable transmission becomes the target shift position corresponding to zero speed. Based on the detected information, the travel operation mechanism 30 is actuated (step 54). In this way, the right continuously variable transmission 11R located on the turning center side can be properly turned while maintaining the zero speed.
[0046]
If the left direction is commanded as the turning direction in step 2, the object to be controlled is opposite to the left and right, but the right continuously variable transmission 11R is set as the reference continuously variable transmission as in steps 3 to 5. Each of the shift position adjustment process, the target rotation speed setting process, and the turning adjustment process is executed (steps 6, 7, and 8).
[0047]
[Another embodiment]
Next, another embodiment is listed.
[0048]
(1) In the above embodiment, four types of modes are set and selected as the relationship between the speed ratios of the left and right continuously variable transmissions 11R and 11L corresponding to the target turning radius with respect to the operation position of the turning lever 26. Although the configuration is used, the configuration is not limited to such a configuration, and the configuration may be such that control is performed only in one mode in which zero speed exists as the target rotational speed. For example, it is good also as a structure provided with any one turning mode in the said belief turning mode, the said low-speed spin turning mode, or the said high-speed spin turning mode. At that time, the adjustment process for turning may be configured as follows instead of the flowchart shown in FIG.
[0049]
For example, if the configuration includes only the belief turning mode, the determination processing of step 50 and step 51 in FIG. 8 is omitted, and based on the determination of whether or not the turning lever is at the maximum operating position of step 52. Alternatively, it may be determined whether the rotational speed adjustment in step 53 is executed or the shift position adjustment corresponding to the zero speed in step 54 is executed.
[0050]
Further, if only the low-speed spin turning mode or the high-speed spin turning mode is provided, the determination processing in step 50 and step 52 in FIG. 8 is omitted, and the target rotation speed in step 51 is zero. Based on the determination of whether or not the speed is high, it may be determined whether the rotational speed adjustment in step 53 is executed or the shift position adjustment corresponding to the zero speed in step 54 is executed.
[0051]
(2) In the above embodiment, as the relationship between the speed ratios of the left and right continuously variable transmissions 11R and 11L corresponding to the target turning radius with respect to the operation position of the turning lever 26, the amount of movement in the direction away from the straight command position is As the larger, the example of what is set as a quadratic function to change the amount of change of the turning radius to the large side with respect to the change per unit amount of the operation position of the turning lever, but is not limited to such a configuration, The change characteristic is not limited as long as the turning radius becomes smaller as the movement amount becomes larger. For example, it can be implemented in various forms such as a linearly changing one or a plurality of straight lines having different inclinations connected to a broken line state.
[0052]
(3) In the above embodiment, the turning command means includes a turning lever as an operation tool that can be swung right and left, and a potentiometer-type turning lever sensor that detects the operation position. For example, it may be implemented in various forms such as a configuration in which a plurality of switches having different commanding radii are commanded or a configuration in which a command is given to change the slewing radius depending on the time of pressing the switch. Good. Also, the vehicle speed command means may be implemented in various forms such as a plurality of switches, similar to the turn command means.
[0053]
(4) In the above embodiment, the hydraulic cylinder is exemplified as the actuator for operating the trunnion shaft of the continuously variable transmission, but other actuators such as a hydraulic motor and an electric motor may be used.
[0054]
(5) In the above embodiment, the hydrostatic continuously variable transmission is used as the pair of continuously variable transmissions. However, instead of such a configuration, for example, other continuously variable transmissions such as a tapered cone type continuously variable transmission are used. A step transmission may be used.
[0055]
(6) In the above embodiment, the combine is exemplified as the work vehicle. However, the present invention is not limited to the combine, and may be another agricultural work vehicle such as a carrot harvester or a radish harvester. Other work vehicles may be used.
[Brief description of the drawings]
FIG. 1 is an overall side view of a combine.
FIG. 2 is a schematic longitudinal rear view showing a transmission structure.
FIG. 3 is a schematic diagram showing a configuration of an operation structure.
FIG. 4 is a diagram showing a relationship between a shift position and a shift output.
FIG. 5 is a diagram showing a relationship between a main shift lever operation position and a target vehicle speed.
FIG. 6 is a flowchart of the control operation.
FIG. 7 is a flowchart of the control operation.
FIG. 8 is a flowchart of the control operation.
FIG. 9 is a diagram showing the relationship between the position of the turning lever and the speed ratio.
[Explanation of symbols]
1R, 1L traveling device
11R, 11L continuously variable transmission
24, 27 Vehicle speed command means
26, 28 Turn command means
29 Object
30 speed change operation means
31 Control means
44, 45 Shift output detection means
46, 47 Shift position detecting means

Claims

A pair of continuously variable transmission for varying speed of the running speed of the pair of left and right traveling devices, a freely shift operation means shifting operation to each other the pair of continuously variable transmission, when and pivot freely commanding straight and turning Turn command means capable of commanding the magnitude of the turn radius, and control means for executing turn control for operating the speed change operation means to perform straight advance and turn based on the command information of the turn command means. A turning control device for a working vehicle,
A pair of shift position detecting means for separately detecting a shift position of an object to be shifted in each of the pair of continuously variable transmissions, and a pair of each detecting an output rotation speed of the pair of continuously variable transmissions Shift output detecting means,
The control means as the turning control,
Based on the output rotational speed of the continuously variable transmission located on the side away from the turning center detected by the shift output detecting means, the speed ratio of the output rotational speeds of the pair of left and right continuously variable transmissions is given to the turning command means. A target rotational speed setting process for obtaining a target rotational speed of the continuously variable transmission located on the turning center side so as to have a speed ratio corresponding to the turning radius commanded
And, when the target rotational speed obtained in the target rotational speed setting process is not zero speed, the shift output so that the output rotational speed of the continuously variable transmission located on the turning center side becomes the target rotational speed. When the speed change operation means is operated based on the detection information of the detection means, and the target rotational speed obtained in the target rotational speed setting process is zero speed, the continuously variable transmission located on the turning center side Each of the turning adjustment processes for operating the speed change operation means based on the detection information of the speed change position detecting means so that the speed change position of the operating object for speed change in the device becomes a target speed change position corresponding to zero speed. A work vehicle turning control device configured to

Vehicle speed command means for commanding a target vehicle speed when the straight command is commanded by the turning command means;
In the turning control, the control means,
Based on the detection information of the shift position detecting means, the shift position of the operating body for shifting in the continuously variable transmission located on the side away from the turning center is the target shift position corresponding to the target vehicle speed. 2. The turning control device for a work vehicle according to claim 1, wherein the turning control device is configured to operate the speed change operation means.

The turning command means is
An operation tool is provided that can be moved and operated over the entire range of the straight operation command position for commanding straight movement and the operation area for turning operation that commands turning, and the operation tool is moved away from the straight command position in the operation area for turning operation. Configured to command a smaller turning radius as it is moved,
The control means, as the target rotation speed setting process,
As the turning radius commanded by the turning command means becomes smaller, the speed gradually becomes lower, and when the smallest turning radius is commanded by the turning command means, the speed is set to zero speed, and is located on the turning center side. 3. The turning control device for a work vehicle according to claim 1, wherein the turning control device is configured to execute a process for obtaining a target rotational speed of the continuously variable transmission.

The turning command means is
An operation tool is provided that can be moved and operated over the entire range of the straight operation command position for commanding straight movement and the operation area for turning operation that commands turning, and the operation tool is moved away from the straight command position in the operation area for turning operation. Configured to command a smaller turning radius as it is moved,
The control means, as the target rotation speed setting process,
As the turning radius commanded by the turning command means becomes smaller, the target rotational speed of the continuously variable transmission located on the turning center side is gradually reduced to zero speed and then gradually increased in the reverse rotation state. The turning control device for a work vehicle according to claim 1 or 2, wherein the turning control device for the work vehicle is configured to execute a process for obtaining the above.

The turning control device for a work vehicle according to any one of claims 1 to 4, wherein each of the pair of continuously variable transmissions is configured by a hydrostatic continuously variable transmission.