JP3586368B2

JP3586368B2 - Connection structure between tractor and work equipment

Info

Publication number: JP3586368B2
Application number: JP05355998A
Authority: JP
Inventors: 光喜平田; 健一郎中島; 隆史内田; 達哉前山
Original assignee: Kubota Corp
Current assignee: Kubota Corp
Priority date: 1998-03-05
Filing date: 1998-03-05
Publication date: 2004-11-10
Anticipated expiration: 2018-03-05
Also published as: JPH11243711A

Description

【０００１】
【発明の属する技術分野】
本発明は、トラクタの車体に標準三点リンク機構を介してロータリ耕耘機等の作業機を装着するようにした、トラクタと作業機との連結構造に関するものである。
【０００２】
【従来の技術】
従来、トラクタとロータリ耕耘機との連結構造として、図９に示すように欧米式の標準三点リンク機構を介してトラクタにロータリ耕耘機を装着するようにしたものがある。
図９において、トラクタの車体８１の後部に、三点リンク機構８２のトップリンク８３の前連結部８３Ｆと左右一対のロアリンク８４の前連結部８４Ｆとが連結され、トップリンク８３の後連結部８３Ｒと左右ロアリンク８４の後連結部８４Ｒとが連結枠８５にそれぞれ連結され、この連結枠８５にロータリ耕耘機の上連結ピン８６と左右一対の下連結ピン８７とが連結され、トラクタの車体８１のＰＴＯ軸８８とロータリ耕耘機のＰＩＣ軸８９とが前後両端側に自在継手を有するドライブシャフト９０で連結されるように構成されている。
【０００３】
【発明が解決しようとする課題】
従来の標準三点リンク機構８２は平行リンク式であることから、枕地旋回又は路上走行時において、ロータリ耕耘機を上昇させた場合にロータリ耕耘機の地上高を確保するために、ロータリ耕耘機がトラクタから大きく離反している。このため、従来の標準三点リンク機構８２によって装着されたトラクタとロータリ耕耘機の連結構造にあっては、トラクタと作業機との前後バランスが悪い、枕地旋回等において旋回範囲が広く旋回性が悪い、ロータリ耕耘機の持上力が大である等の欠点、改良点が指摘されている。
【０００４】
そこで、本発明は、標準三点リンク機構における前記課題を解決するトラクタと作業機との連結構造を提供することを目的とする。
【０００５】
【課題を解決するための手段】
本発明が前記目的を達成するために講じた技術的手段は、車体４の後部に、トップリンク７及び左右一対のロワーリンク８からなる三点リンク機構３が連結され、この三点リンク機構３の後端部に連結枠１５が連結され、この連結枠１５に、作業機上取付点Ｐ５と、この作業機上取付点Ｐ５の下側に位置する作業機下取付点Ｐ６とでロータリ耕耘機２が取り付けられるように構成され、
車体４のＰＴＯ軸４９とロータリ耕耘機２のＰＩＣ軸１６とが、ＰＴＯ軸４９に連結される等速自在継手５１とＰＩＣ軸に連結される作業機側自在継手５２とを備えたドライブシャフト５０によって連動連結され、
前記三点リンク機構３は、ロータリ耕耘機２が接地状態から上昇する際におけるトップリンク７の作業機側連結点Ｐ３の軌跡が、ロワーリンク８の作業機側連結点Ｐ４の軌跡の外側を通り、且つトップリンク７のトラクタ側連結点Ｐ１がＰＴＯ軸４９の上方に位置する標準三点リンク機構とされ、
ロータリ耕耘機２の標準耕耘時の位置から最上昇時までの範囲で、ドライブシャフト５０の作業機側自在継手５２の折れ角の変動が少なくなるように、トップリンク７は、ロワーリンク８の長さよりも短いと共に、ロータリ耕耘機２が接地状態で且つ側面視において、トップリンク７のトラクタ側連結点Ｐ１及び作業機側連結点Ｐ３を通る線分Ａが、ロワーリンク８のトラクタ側連結点Ｐ２及び作業機側連結点Ｐ４を通る線分Ｂの延長線上でロワーリンク８のトラクタ側連結点Ｐ２の直前を通り、且つ、トップリンク７のトラクタ側連結点Ｐ１が、ＰＴＯ軸４９とドライブシャフト５０とのジョイント部分の略真上に位置するように前下がり傾斜状とされ、且つ、側面視において、トップリンク７のトラクタ側連結点Ｐ１及び作業機側連結点Ｐ３を通る線分Ａと、ロワーリンク８のトラクタ側連結点Ｐ２及び作業機側連結点Ｐ４を通る線分Ｂとが成す角θ１の略２等分線Ｅ上に、ＰＴＯ軸４９に連結されるドライブシャフト５０の等速自在継手５１を位置させ、
側面視において、ロータリ耕耘機２のＰＩＣ軸１６がロワーリンク８の作業機側連結点Ｐ４の上方に位置するように、該ＰＩＣ軸１６が作業機上取付点Ｐ５と作業機下取付点Ｐ６とを結ぶ仮想線Ｆよりも前方に入り込むように構成されていることを特徴とする。
【０００６】
また、トップリンク７の後端側を連結する、連結枠１５の上部連結体３２が上方に向かうにしたがって前方に移行するように傾斜状とされているのがよい。
また、ＰＩＣ軸１６の先端部と、ロワーリンク８の作業機側連結点Ｐ４と、作業機下取付点Ｐ６とを側面視において三角配置すると共に、ＰＩＣ軸１６の先端部がロワーリンク８の作業機側連結点Ｐ４の真上に位置するのがよい。
【０００７】
また、ロワーリンク（８）のトラクタ側連結点（Ｐ２）がＰＴＯ軸（４９）の前方側に位置するのがよい。
【０００８】
また、連結枠１５の、ロータリ耕耘機２が取り付けられる作業機下取付点Ｐ６のロック解除操作をする操作レバー４８が連結枠１５の前側に配置されているのがよい。
また、ドライブシャフト５０の作業機側自在継手５２の折れ角は、ロータリ耕耘機２の標準耕耘時の位置から最上昇時までの範囲で、中途部の折れ角のない状態から±１０°とされているのがよい。
【０００９】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて説明する。
図１及び図２は、トラクタ１と、作業機として例示するロータリ耕耘機２とを標準三点リンク機構３を介して連結する連結構造を示す。
図１及び図２に示すように、トラクタ１の車体４の一部を構成するミッションケース４Ａの後部上には油圧シリンダを有する作業機昇降装置５が搭載され、この作業機昇降装置５の背面にはブラケット６が固定されている。このブラケット６にはピン挿通孔から構成された５つの連結部６ａが下方に向かうにしたがって後方に移行するように傾斜状に配置されて形成されている。
【００１０】
三点リンク機構３は、車体４の左右方向略中央部に位置する上部のトップリンク７と、車体４の左右両側に位置する下部の一対のロワーリンク８とから構成されており、三点リンク機構３の後端側には連結枠１５が固定されていて該連結枠１５によって三点リンク機構３の後端側が連結されており、この連結枠１５にロータリ耕耘機２が着脱自在に装着される。
【００１１】
トップリンク７はターンバックル構造により軸心方向伸縮自在とされていて長さ調節自在に構成され、このトップリンク７の前側の連結部７Ｆは、前記ブラケット６の最下部の連結部６ａに連結ピン９を介して左右方向の軸心廻りに回動自在に枢支連結されており、この部分がトップリンク７のトラクタ側連結点Ｐ１とされている。
【００１２】
ロワーリンク８の前側の連結部８Ｆは、ミッションケース４Ａの側面下部に連結ピン１１を介して左右方向の軸心廻りに回動自在に枢支連結されており、この部分が左右ロワーリンク８のトラクタ側連結点Ｐ２とされている。また、各ロワーリンク８の中途部は、作業機昇降装置５のリフトアーム１２にリフトロッド１３を介して連結されており、リフトアーム１２の左右方向の軸心廻りの回動によって、三点リンク機構３が連結点Ｐ１，Ｐ２廻りに昇降自在とされている。
【００１３】
なお、リフトロッド１３のロワーリンク８への連結点はピン装着機構とされ、ロワーリンク８に形成されるピン挿通孔１４は長手方向に複数形成されている。前記ロータリ耕耘機２は、ＰＩＣ軸１６を前方突出したギヤケース１７からサポートアーム１８を左右に突出し、左側サポートアーム１８に伝動ケース１９を、右側サポートアーム１８にサイドフレームをそれぞれ固定してなる機枠を備え、伝動ケース１９とサイドフレームの下部間に爪軸２０を左右方向の軸心廻りに回動自在に支架すると共に、爪軸２０上に多数の耕耘爪２１を取り付けて構成されてなる耕耘部２２を備える。
【００１４】
前記耕耘部２２は上方，後方及び後部側方を耕耘カバー２３によってカバーされ、ギヤケース１７上にはトップマスト２４が固定され、左右サポートアーム１８にはゲージ輪を支持する支持枠２６が後方突出状に設けられ、この支持枠２６とトップマスト２４との間には支持枠２６を上下に揺動させてゲージ輪の高さを調節する高さ調節機構２７が設けられている。
【００１５】
前記トップマスト２４の前部上端側には左右方向の軸心を有する上連結ピン２８が設けられ、左右各サポートアーム１８には夫々連結ブラケット２９が固定され、左右の各連結ブラケット２９には夫々下連結ピン３０が左右方向外方に突出状に設けられている。
連結枠１５は、図１〜４に示すように、角パイプ（又は丸パイプ，フラットバー等）で主構成されており、背面視山形状に形成された主枠材３１Ａの左右側部の上下方向中途部を上補強材３１Ｂで連結して背面視略Ａ形状に形成された主フレーム３１を有する。
【００１６】
主枠材３１Ａの中央上部には上部連結体３２が上方に向かうにしたがって前方に移行するように傾斜状に固定され、上部連結体３２の後部で主枠材３１Ａ中央上部には係合部材３４が固定されている。主枠材３１Ａの左右両側下部には下部連結体３３が固定され、この左右下部連結体３３は角パイプ等で形成した下補強材３５で繋がれ、上下補強材３１Ｂ，３５が左右一対の縦補強材３６で繋がれている。
【００１７】
上部連結体３２の前上部には左右方向の上連結ピン３７が設けられ、この上連結ピン３７にトップリンク７の後側の連結部７Ｒが左右方向の軸心廻りに回動自在に枢支連結され、この部分がトップリンク７の作業機側連結点Ｐ３とされている。
また、前記係合部材３４には、上方開放状に凹設されてなる上係合部３８が形成され、この上係合部３８にロータリ耕耘機２の上連結ピン２８が上方から左右軸廻りに回動可能に嵌合しており、この部分が作業機上取付点Ｐ５とされている。
【００１８】
左右各下部連結体３３の前下方に突出した部分には下連結ピン３９が左右方向外側方に突出状に設けられ、この下連結ピン３９にはロワーリンク８の後側の連結部８Ｒが左右軸廻りに回動自在に枢支連結されており、この部分がロワーリンク８の作業機側連結点Ｐ４とされている。
また、下部連結体３３の後部には、後方開放凹状の下係合部４０が形成され、この下係合部４０にロータリ耕耘機２の下連結ピン３０が後方から左右軸廻りに回動可能に係合されており、この部分が作業機下取付点Ｐ６とされている。
【００１９】
図３及び図４に示すように、下部連結体３３には、横軸４１を介してロック部材４２が左右軸廻りに回動可能に支持されており、このロック部材４２の後部は下係合部４０に係合した下連結ピン３０に係合可能であり、係合することにより下係合部４０からした下連結ピン３０が離脱するのを阻止している。
前記下係合部４０、下連結ピン３０及びロック部材４２等で、ロータリ耕耘機２を連結枠１５の作業機下取付点Ｐ６に連結する連結機構を構成している。
【００２０】
ロック部材４２は、その後部がコイルバネ４３により下連結ピン３０に係合する方向に付勢されており、その前部は解除手段４４の背面視山形状のリンク４５に連結されている。この解除手段４４は以下のように構成されている。
すなわち、上補強材３１Ｂに固定のブラケット４６にアーム４７の下部が左右方向の支軸４６ａを介して枢支され、このアーム４７の上部側にリンク４５の中央が相対回転自在に貫通され、また、アーム４７の前面側に、連結枠１５（主フレーム３１）の前側に配置された操作レバー４８の下端側が固定されている。
【００２１】
前記操作レバー４８を図４の実線状態から前方に倒して２点鎖線の位置まで回動操作することにより、リンク４５が支軸４６ａ（アーム４７の枢支部分）を越えて前方に移動すると共に上方にも移動し、これによってロック部材４２の前部が引き上げられて、ロック部材４２が図４の時計方向に回動して下連結ピン３０との係合が解除されるようになっている。
【００２２】
なお、リンク４５は、２点鎖線で示す位置では、コイルバネ４３の付勢力によって引き下げられる方向に付勢されていて、アーム４７が前方に回動する方向に付勢されているが、操作レバー４８の下端部がブラケット４６に接当していて、アーム４７の前方への回動が規制されており、これによってロック部材４２が２点鎖線で示す位置に保持される。
【００２３】
トラクタ１の車体４の後部には、後面の略左右方向中央部から後方に突出するＰＴＯ軸４９が設けられて、エンジンからの動力を取り出せるようになっており、このＰＴＯ軸４９と、ロータリ耕耘機２のＰＩＣ軸１６とはドライブシャフト５０によって連動連結されており、トラクタ１のエンジンからの回転動力がロータリ耕耘機２のギヤケース１７内の伝動機構に入力されるようになっている。
【００２４】
なお、ギヤケース１７からは、左側サポートアーム１８内の伝動軸、伝動ケース１９内の伝動機構を経て爪軸２０に動力が伝達されて、該爪軸２０が左右方向の軸心廻りに回転駆動されるようになっている。
また、ＰＴＯ軸４９とＰＩＣ軸１６とは左右方向に関して略一致する位置に配置される。
【００２５】
図２に示すように、前記ドライブシャフト５０は、前部（トラクタ側）にＰＴＯ軸４９に連結される２組のフック式継手からなる等角自在継手（等速自在継手）５１を、後部（作業機側）にＰＩＣ軸１６に連結される１組のフック式継手からなる自在継手５２を備えると共に、これら自在継手５１，５２のヨークに連動連結された伝動軸５３を備えてなり、伝動軸５３は軸心方向に伸縮自在に構成されている。
【００２６】
また、ＰＴＯ軸４９とドライブシャフト５０とのジョイント部分の略真上には、トップリンク７のトラクタ側連結点Ｐ１が位置するように構成されている。
後部の自在継手５２のヨーク５４は円筒体５６にベアリングを介して回転自在に支持され、円筒体５６はホルダを介して連結枠１５の左右縦補強材３６に支持されている。
【００２７】
次に、ロータリ耕耘機１の接地状態での、三点リンク機構３と各連結点Ｐ１，Ｐ２，Ｐ３，Ｐ４との関係等を、図１及び図２に示す側面視の図面（左右方向に直交する投象面に、トラクタ１、三点リンク機構３、連結枠１５、ロータリ耕耘機２等を直投象した投象図）に基づいて説明する。したがって、左右方向の関係は無視する。
【００２８】
ロワーリンク８は、若干後下がりで前後方向に配置され、トップリンク７の作業機側連結点Ｐ３はロワーリンク８の作業機側連結点Ｐ４よりも前方に位置する。また、トップリンク７のトラクタ側連結点Ｐ１及び作業機側連結点Ｐ３を通る線分Ａ（連結ピン９の軸心と上連結ピン３７の軸心とを通る線分）がロワーリンク８のトラクタ側連結点Ｐ２の直前を通るようになっており、この線分Ａと、ロワーリンク８のトラクタ側連結点Ｐ２及び作業機側連結点Ｐ４を通る線分Ｂ（連結ピン１１の軸心と下連結ピン３９の軸心とを通る線分）との交点Ｃ、トップリンク７の作業機側連結点Ｐ３（上連結ピン３７の軸心）、及びロワーリンク８の作業機側連結点Ｐ４（下連結ピン３９の軸心）を頂点とする３角形［線分Ａと、線分Ｂと、トップリンク７の作業機側連結点Ｐ３及びロワーリンク８の作業機側連結点Ｐ４を通る線分Ｄ（上連結ピン３７の軸心と下連結ピン３９の軸心とを通る線分）とで形成される３角形］の各内角θ１，θ２，θ３が鋭角となるように構成されている。
【００２９】
また、この線分Ａと、線分Ｂと、線分Ｄとで構成される３角形は、線分Ａと、線分Ｂとを（交点Ｃと上連結ピン３７の軸心と結ぶ線分と、交点Ｃと連結ピン３９の軸心とを結ぶ線分とを）略等しい２辺とする２等辺３角形とされており、線分Ａと、線分Ｂとが成す角θ１の２等分線Ｅ上（又はその近傍）に、ＰＴＯ軸４９に連結されるドライブシャフト５０の等角自在継手５１を位置させている。さらに、図６に示すロータリ耕耘機２の標準耕耘時、図７に示すロータリ耕耘機２の中間上昇時、図８に示すロータリ耕耘機２の最上昇時においても、線分Ａと、線分Ｂとが成す角θ１の２等分線Ｅ上に、ＰＴＯ軸４９に連結されるドライブシャフト５０の等角自在継手５１が位置していて、図５〜８に示すように、ロータリ耕耘機２の標準耕耘時の位置から最上昇時までの範囲で、ドライブシャフト５０の作業機側自在継手５２の折れ角（伝動軸５３とＰＩＣ軸１６との成す角）の変動が少ないように構成されている（図例では、折れ角のない状態から±１０°程度とされている）。これにより、伝動軸５３の回転に対するＰＩＣ軸１６の進み遅れ（回転角速度の変動）を少なくでき、トルク変動を少なくすることができる。
【００３０】
また、前記構成により、図５〜８に示すように、ロータリ耕耘機２は、接地位置と標準耕耘位置との間では略平行に昇降し、中間上昇位置から最上昇位置にかけて、トラクタ１側に近づくように持ち上げられる。これによって、従来のものに比してロータリ耕耘機２をトラクタ１側に接近させたものであっても、ロータリ耕耘機２を上昇させたときの位置を高く採れ、これによって、枕地旋回等における旋回範囲を小さく採れると共に、旋回・走行時にオーバハング重量効果によるトラクタの不安定走行を抑制することができ、さらに、トラクタ１とロータリ耕耘機２との前後バランスがよく、作業機昇降装置５の油圧力（ロータリ耕耘機２の持上げ力）が小さくてすむという効果を奏する。
【００３１】
また、ＰＩＣ軸１６は作業機上取付点Ｐ５及び作業機下取付点Ｐ６を通る線分Ｆ（上連結ピン２８の軸心と下連結ピン３０の軸心とを通る線分）よりも、前方に入り込むように構成されている。
また、連結枠１５の主フレーム３１は若干ではあるが前傾状とされている。
次に、作業機装着動作を説明する。
【００３２】
図１及び２において、車体４に三点リンク機構３を連結すると共に、三点リンク機構３に連結枠１５を連結する。また、ロック部材４２はロック位置（図４において実線及び破線で描いた位置）にしておく。その状態で地面に倒れないように保持した状態で載置されたロータリ耕耘機２に対して車体２を後進させて、連結枠１５の上係合部３８の上方にロータリ耕耘機２の上連結ピン２８が位置するようにトラクタ１をロータリ耕耘機２に接近させる。
【００３３】
そして、作業機昇降装置５を作動して連結枠１５を上昇させ、上連結ピン２８を上係合部３８に係合させ、さらに連結枠１５を上昇させてロータリ耕耘機２を吊り上げるようにすると、ロータリ耕耘機２が作業機上取付点Ｐ５を支点として前方に回動するように若干前移動して、ロータリ耕耘機２の下連結ピン３０がロック部材４２を押し下げながら連結枠１５の下係合部４０に係合していく。
【００３４】
そして、下連結ピン３０が下係合部４０に係合するとロック部材４２がバネ４３の付勢力によって後部側が上方に回動し、下連結ピン３０をロックする。
一方、ロータリ耕耘機２が吊り上げられて若干前移動するときに、下連結ピン３０が下係合部４０に係合するのと並行してＰＩＣ軸１６が自在継手５２のヨーク５４に自動的にスプライン嵌合される。
【００３５】
以上のようにして、連結枠１５に、ロータリ耕耘機２が上方に向かうに従って前方に移行する傾斜状として連結される。
また、ロータリ耕耘機２をトラクタ１から取り外すには、ロータリ耕耘機２を上昇させて、解除手段４４の操作レバー４８を図４に仮想線で示す位置まで手前に倒す。このとき、操作レバー４８は連結枠１５の前側に位置するので、トラクタ１上の運転者側から操作し易いという利点がある。
【００３６】
前記構成のものにおいて、ロータリ耕耘機２を上昇させる際には、ドライブシャフト５０は前側の継手部分を中心に折れるが、前述したようにロータリ耕耘機２の上昇位置を高く採ると、ドライブシャフト５０の前側の折れ角（伝動軸５３とＰＴＯ軸４９との成す角）の増大によるドライブシャフト５０の回転角速度の変動が大きくなり、また、上昇時には耕耘部２２に負荷がかかっていないことから、上昇時に騒音が大きくなるが、前記実施の形態にあっては、ドライブシャフト５０の前側に等速自在継手５１が採用されているので、回転角速度の変動に起因する騒音を防止することができる。
【００３７】
【発明の効果】
本発明によれば、枕地旋回又は路上走行時等において、作業機を上昇させた場合に、作業機がトラクタに近づくように持ち上げられ、該作業機の地上高を高く採ることができ、したがって、トラクタに標準三点リンク機構を介して作業機を装着したものにおいて、トラクタに対して作業機を接近させるように装着しても、作業機を上昇させた時の、該作業機の地上高を十分な高さに確保でき、そして、トラクタに対して作業機を接近させることができるので、トラクタと作業機との前後バランスを良くしたり、旋回に要する範囲を小さくしたり、作業機の持上げ力を少なくできる。
【００３８】
また、側面視において、トップリンクのトラクタ側連結点及び作業機側連結点を通る線分と、ロワーリンクのトラクタ側連結点及び作業機側連結点を通る線分とが成す角の２等分線上又はその近傍に、ＰＴＯ軸に連結されるドライブシャフトの継手が位置するように構成することで、作業機を昇降する際において、ドライブシャフトの、ＰＩＣ軸との連結側の折れ角の変動が少なく、したがって、ドライブシャフトの、ＰＩＣ軸との連結側の折れ角が小さい状態で、作業機を昇降させることができる。
【図面の簡単な説明】
【図１】トラクタと作業機の連結構造を示す要部の側面図である。
【図２】トラクタと作業機の連結構造を示す全体側面図である。
【図３】連結枠の正面図である。
【図４】作業機連結部分の側面図である。
【図５】作業機の接地状態の側面図である。
【図６】作業機の標準耕耘時の側面図である。
【図７】作業機の中間上昇時の側面図である。
【図８】作業機の最上昇時の側面図である。
【図９】従来のトラクタと作業機との連結構造を示す側面図である。
【符号の説明】
２ロータリ耕耘機（作業機）
４車体
７トップリンク
８ロワーリンク
１５連結枠
１６ＰＩＣ軸
３２上部連結体
４８操作レバー
４９ＰＴＯ軸
５０ドライブシャフト
５１等角自在継手
Ｐ１トラクタ側連結点
Ｐ２トラクタ側連結点
Ｐ３作業機側連結点
Ｐ４作業機側連結点
Ｐ５作業機上取付点
Ｐ６作業機下取付点
Ａ線分
Ｂ線分
Ｃ線分
Ｆ線分
θ１内角
θ２内角
θ３内角[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a connection structure between a tractor and a working machine, in which a working machine such as a rotary cultivator is mounted on a vehicle body of a tractor via a standard three-point link mechanism.
[0002]
[Prior art]
Conventionally, as a coupling structure between the tractor and the rotary tiller, is that so as to mount the rotary tiller to the tractor via a Western type of standard three-point linkage mechanism as shown in FIG.
9 , a front connecting portion 83F of a top link 83 of a three-point link mechanism 82 and a front connecting portion 84F of a pair of left and right lower links 84 are connected to a rear portion of a vehicle body 81 of the tractor. 83R and a rear connecting portion 84R of the left and right lower links 84 are respectively connected to a connecting frame 85, and an upper connecting pin 86 and a pair of left and right lower connecting pins 87 of the rotary cultivator are connected to the connecting frame 85. The PTO shaft 81 and the PIC shaft 89 of the rotary tiller are connected by a drive shaft 90 having universal joints at both front and rear ends.
[0003]
[Problems to be solved by the invention]
Since the conventional standard three-point link mechanism 82 is a parallel link type, when turning the headland or traveling on the road, in order to secure the ground height of the rotary tiller when the rotary tiller is raised, the rotary tiller is used. Is far away from the tractor. For this reason, in the connection structure between the tractor and the rotary cultivator mounted by the conventional standard three-point link mechanism 82, the front-rear balance between the tractor and the work implement is poor, and the turning range is wide in headland turning and the like. However, it has been pointed out that there are drawbacks and improvements such as poor rotation, large lifting power of the rotary tiller.
[0004]
Therefore, an object of the present invention is to provide a connection structure between a tractor and a working machine that solves the above-mentioned problem in the standard three-point link mechanism.
[0005]
[Means for Solving the Problems]
The technical means taken by the present invention to achieve the above object is that a three-point link mechanism 3 including a top link 7 and a pair of left and right lower links 8 is connected to a rear portion of the vehicle body 4. A connecting frame 15 is connected to the rear end of the rotary cultivator. The connecting frame 15 is connected to a work implement mounting point P5 and a work implement lower mounting point P6 located below the working machine upper mounting point P5. 2 is configured to be attached,
A drive shaft 50 having a PTO shaft 49 of the vehicle body 4 and a PIC shaft 16 of the rotary cultivator 2 having a constant velocity universal joint 51 connected to the PTO shaft 49 and a work implement-side universal joint 52 connected to the PIC shaft. Linked by
The three-point link mechanism 3 is configured such that the locus of the work implement side connection point P3 of the top link 7 when the rotary tiller 2 rises from the ground contact state passes outside the locus of the work implement side connection point P4 of the lower link 8. And a standard three-point link mechanism in which the tractor-side connection point P1 of the top link 7 is located above the PTO shaft 49,
The top link 7 has a length equal to the length of the lower link 8 so that the variation of the bending angle of the work implement-side universal joint 52 of the drive shaft 50 is reduced in a range from the position of the rotary tiller 2 at the time of standard tillage to the highest. And the line segment A passing through the tractor-side connection point P1 and the work implement-side connection point P3 of the top link 7 when the rotary tiller 2 is in the ground contact state and in a side view, is connected to the tractor-side connection point P2 of the lower link 8. The tractor-side connection point P1 of the top link 7 passes through the PTO shaft 49 and the drive shaft 50 immediately before the tractor-side connection point P2 of the lower link 8 on an extension of the line segment B passing through the work implement-side connection point P4. forwardly downwardly so as to be positioned substantially directly above the joint part between an inclined shape, and, in a side view, the tractor-side coupling point P1 and the working machine side coupling point of the top link 7 3 and a line segment B passing through the tractor-side connection point P2 and the work implement-side connection point P4 of the lower link 8 on an approximately bisector E of an angle θ1, which is connected to the PTO shaft 49. The constant velocity universal joint 51 of the drive shaft 50
When viewed sideways, the PIC shaft 16 of the rotary tiller 2 is positioned above the work implement mounting point P5 and the work implement lower mounting point P6 such that the PIC shaft 16 is located above the work implement side connection point P4 of the lower link 8. characterized in that it is configured so as to enter the front of the virtual line F connecting.
[0006]
Further, it is preferable that the upper link 32 of the connection frame 15 that connects the rear ends of the top links 7 is inclined so as to move forward as the upper connection body 32 moves upward.
In addition, the tip of the PIC shaft 16, the working machine side connection point P4 of the lower link 8, and the attachment point P6 under the working machine are arranged in a triangular shape in a side view, and the tip of the PIC shaft 16 is used for the work of the lower link 8. It is good to be located just above the machine side connection point P4.
[0007]
The tractor-side connection point (P2) of the lower link (8) is preferably located on the front side of the PTO shaft (49) .
[0008]
Further, it is preferable that an operation lever 48 for unlocking the work implement lower attachment point P6 of the connection frame 15 to which the rotary cultivator 2 is mounted is disposed on the front side of the connection frame 15.
In addition, the bending angle of the work implement-side universal joint 52 of the drive shaft 50 is ± 10 ° from a state where there is no bending angle in the middle part within a range from the position of the rotary tiller 2 at the time of the standard plowing to the highest. is good to have.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIGS. 1 and 2 show a connection structure for connecting a tractor 1 and a rotary tiller 2 exemplified as a working machine via a standard three-point link mechanism 3.
As shown in FIGS. 1 and 2, a work implement lifting / lowering device 5 having a hydraulic cylinder is mounted on a rear portion of a transmission case 4 </ b> A constituting a part of the vehicle body 4 of the tractor 1. Is fixed to the bracket 6. The bracket 6 is formed with five connecting portions 6a formed of pin insertion holes, which are arranged in an inclined manner so as to shift rearward as going downward.
[0010]
The three-point link mechanism 3 includes an upper top link 7 located substantially at the center of the vehicle body 4 in the left-right direction, and a pair of lower links 8 located at left and right sides of the vehicle body 4. A connecting frame 15 is fixed to the rear end of the mechanism 3, and the rear end of the three-point link mechanism 3 is connected by the connecting frame 15. The rotary tiller 2 is detachably mounted on the connecting frame 15. You.
[0011]
The top link 7 is configured to be extendable and contractible in the axial direction by a turnbuckle structure, and is configured to be adjustable in length. A front connecting portion 7F of the top link 7 is connected to a lowermost connecting portion 6a of the bracket 6 by a connecting pin. 9, and is pivotally connected to the left and right directions around an axial center, and this portion is a tractor-side connection point P1 of the top link 7.
[0012]
The front connecting portion 8F of the lower link 8 is rotatably connected to the lower portion of the side surface of the transmission case 4A via a connecting pin 11 so as to be rotatable around the left-right axis. The tractor side connection point P2 is set. An intermediate portion of each lower link 8 is connected to a lift arm 12 of the work implement lifting device 5 via a lift rod 13, and the three-point link is formed by the rotation of the lift arm 12 around the left-right axis. The mechanism 3 is movable up and down around the connection points P1 and P2.
[0013]
The connection point of the lift rod 13 to the lower link 8 is a pin mounting mechanism, and a plurality of pin insertion holes 14 formed in the lower link 8 are formed in the longitudinal direction. The rotary tiller 2 has a machine frame in which a support arm 18 is protruded left and right from a gear case 17 in which a PIC shaft 16 protrudes forward, a transmission case 19 is fixed to a left support arm 18, and a side frame is fixed to a right support arm 18, respectively. And a plurality of tilling claws 21 mounted on the claw shaft 20 while rotatably supporting the claw shaft 20 between the transmission case 19 and the lower portion of the side frame. A part 22 is provided.
[0014]
The tilling part 22 is covered with a tilling cover 23 on the upper, rear and rear sides, a top mast 24 is fixed on the gear case 17, and a support frame 26 for supporting a gauge wheel is formed on the left and right support arms 18 so as to project rearward. And a height adjusting mechanism 27 that adjusts the height of the gauge wheel by swinging the support frame 26 up and down between the support frame 26 and the top mast 24.
[0015]
An upper connecting pin 28 having an axis in the left-right direction is provided on the front upper end side of the top mast 24, and a connecting bracket 29 is fixed to each of the left and right support arms 18, and each of the left and right connecting brackets 29 is respectively fixed. The lower connecting pin 30 is provided so as to protrude outward in the left-right direction.
As shown in FIGS. 1 to 4, the connection frame 15 is mainly formed of a square pipe (or a round pipe, a flat bar, or the like), and the upper and lower sides of the left and right sides of the main frame member 31A formed in a mountain shape in rear view. It has a main frame 31 which is formed in a substantially A-shape in rear view by connecting the middle part in the direction with an upper reinforcing material 31B.
[0016]
An upper connector 32 is fixed to the upper center of the main frame member 31A in an inclined manner so as to move forward as it goes upward, and an engaging member 34 is provided at the rear upper portion of the upper connector 32 at the upper center of the main frame member 31A. Has been fixed. Lower connecting members 33 are fixed to lower portions on both left and right sides of the main frame member 31A. The lower left and right connecting members 33 are connected by a lower reinforcing member 35 formed of a square pipe or the like. They are connected by a reinforcing member 36.
[0017]
An upper connection pin 37 in the left-right direction is provided at the front upper portion of the upper connection body 32, and a connection portion 7R on the rear side of the top link 7 is pivotally supported on the upper connection pin 37 so as to be rotatable around the left-right axis. These portions are connected to a work implement side connection point P3 of the top link 7.
The engaging member 34 is formed with an upper engaging portion 38 that is concavely opened upward, and the upper connecting pin 28 of the rotary tiller 2 is pivotally mounted on the upper engaging portion 38 from above in the left-right direction. , And this portion is set as a mounting point P5 on the working machine.
[0018]
A lower connecting pin 39 is provided at a portion protruding forward and downward of each of the left and right lower connecting bodies 33 so as to protrude outward in the left-right direction. The lower connecting pin 39 is provided with a connecting part 8R on the rear side of the lower link 8. The lower link 8 is pivotally connected to the work machine so as to be rotatable around the axis, and this portion is defined as a working machine side connection point P4 of the lower link 8.
A lower engaging portion 40 is formed at the rear of the lower connecting body 33. The lower connecting portion 30 of the rotary cultivator 2 is rotatable around the left-right axis from behind. , And this portion is set as a work machine lower attachment point P6.
[0019]
As shown in FIGS. 3 and 4, a lock member 42 is supported by the lower connecting body 33 via a horizontal shaft 41 so as to be rotatable around the left and right axes. The lower coupling pin 30 engaged with the portion 40 can be engaged with the lower coupling pin 30, and the engagement prevents the lower coupling pin 30 from being disengaged from the lower engagement portion 40.
The lower engaging portion 40, the lower connecting pin 30, the lock member 42, and the like constitute a connecting mechanism that connects the rotary tiller 2 to the work implement lower attachment point P6 of the connecting frame 15.
[0020]
The rear portion of the lock member 42 is urged by a coil spring 43 in a direction in which it engages with the lower connection pin 30, and the front portion thereof is connected to a mountain-shaped link 45 of the release means 44 in a rear view. The releasing means 44 is configured as follows.
That is, the lower portion of the arm 47 is pivotally supported by a bracket 46 fixed to the upper reinforcing member 31B via a horizontal support shaft 46a, and the center of the link 45 is penetrated through the upper side of the arm 47 so as to be relatively rotatable. On the front side of the arm 47, a lower end side of an operation lever 48 disposed in front of the connecting frame 15 (main frame 31) is fixed.
[0021]
The link 45 is moved forward beyond the support shaft 46a (the pivot portion of the arm 47) by rotating the operation lever 48 forward from the solid line state in FIG. The lock member 42 also moves upward, whereby the front portion of the lock member 42 is pulled up, and the lock member 42 is rotated clockwise in FIG. 4 to release the engagement with the lower connecting pin 30. .
[0022]
At the position shown by the two-dot chain line, the link 45 is urged in a direction in which it is pulled down by the urging force of the coil spring 43 and is urged in a direction in which the arm 47 rotates forward. Is in contact with the bracket 46, and the forward rotation of the arm 47 is restricted, whereby the lock member 42 is held at the position shown by the two-dot chain line.
[0023]
A PTO shaft 49 is provided at a rear portion of the vehicle body 4 of the tractor 1 so as to protrude rearward from a substantially central portion of the rear surface in the left-right direction, so that power from the engine can be taken out. The PIC shaft 16 of the power plant 2 is operatively connected to the PIC shaft 16 by a drive shaft 50, and rotational power from the engine of the tractor 1 is input to a transmission mechanism in a gear case 17 of the rotary cultivator 2.
[0024]
Power is transmitted from the gear case 17 to the pawl shaft 20 via a transmission shaft in the left support arm 18 and a transmission mechanism in the transmission case 19, and the pawl shaft 20 is driven to rotate about the left-right axis. It has become so.
In addition, the PTO shaft 49 and the PIC shaft 16 are arranged at positions substantially matching in the left-right direction.
[0025]
As shown in FIG. 2, the drive shaft 50 has a conformal universal joint (constant velocity universal joint) 51 composed of two sets of hook type joints connected to the PTO shaft 49 at a front portion (tractor side), and a rear portion ( The work machine includes a universal joint 52 composed of a set of hook-type joints connected to the PIC shaft 16 and a transmission shaft 53 interlocked to the yokes of the universal joints 51 and 52. 53 is configured to be extendable and contractible in the axial direction.
[0026]
The tractor-side connection point P1 of the top link 7 is configured to be located substantially directly above the joint between the PTO shaft 49 and the drive shaft 50.
The yoke 54 of the rear universal joint 52 is rotatably supported by a cylindrical body 56 via a bearing, and the cylindrical body 56 is supported by the left and right vertical reinforcing members 36 of the connection frame 15 via a holder.
[0027]
Next, the relationship between the three-point link mechanism 3 and the connection points P1, P2, P3, and P4 in the ground contact state of the rotary tiller 1 will be described with reference to the side view drawings (in the left-right direction) shown in FIGS. A description will be given based on a projection view in which the tractor 1, the three-point link mechanism 3, the connection frame 15, the rotary tiller 2, and the like are directly cast on the orthogonal projection plane). Therefore, the relationship in the left-right direction is ignored.
[0028]
The lower link 8 is arranged in the front-rear direction with a slight downward descent, and the work implement side connection point P3 of the top link 7 is located forward of the work implement side connection point P4 of the lower link 8. The line segment A (the line segment passing through the axis of the connecting pin 9 and the axis of the upper connecting pin 37) passing through the tractor-side connection point P1 and the work implement-side connection point P3 of the top link 7 is the tractor of the lower link 8. The line segment A passes immediately before the side connection point P2, and the line segment A and the line segment B passing through the tractor side connection point P2 and the work implement side connection point P4 of the lower link 8 (the axis center of the connection pin 11 and the An intersection C with a line passing through the axis of the connecting pin 39, a working machine-side connecting point P3 of the top link 7 (an axis of the upper connecting pin 37), and a working machine-side connecting point P4 of the lower link 8 (lower). A triangle having the vertex of the connecting pin 39 (the axis of the connecting pin 39) [a line segment A and a line segment B, and a line segment D passing through the working machine side connecting point P3 of the top link 7 and the working machine side connecting point P4 of the lower link 8]. (A line passing through the axis of the upper connecting pin 37 and the axis of the lower connecting pin 39). Triangle] of each interior angle θ1, θ2, θ3 are configured such that an acute angle.
[0029]
The triangle formed by the line segment A, the line segment B, and the line segment D is a line segment connecting the line segment A and the line segment B (the line segment connecting the intersection C with the axis of the upper connecting pin 37). And a line segment connecting the intersection C and the axis of the connecting pin 39) is an isosceles triangular shape having substantially equal two sides, and the angle θ1 formed by the line segment A and the line segment B is equal to two. The conformal universal joint 51 of the drive shaft 50 connected to the PTO shaft 49 is located on (or near) the dividing line E. Further, at the time of standard tillage of the rotary tiller 2 shown in FIG. 6, at the time of intermediate ascent of the rotary tiller 2 shown in FIG. 7, and at the time of the maximum ascent of the rotary tiller 2 shown in FIG. B, the equiangular universal joint 51 of the drive shaft 50 connected to the PTO shaft 49 is located on the bisector E of the angle θ1, and as shown in FIGS. In the range from the position at the time of the standard tilling to the time of the highest ascending, the bending angle (the angle formed by the transmission shaft 53 and the PIC shaft 16) of the work implement-side universal joint 52 of the drive shaft 50 is configured to be small. (In the illustrated example, the angle is set to about ± 10 ° from a state where there is no bent angle). Thereby, the advance / delay of the PIC shaft 16 with respect to the rotation of the transmission shaft 53 (fluctuation in the rotational angular velocity) can be reduced, and the torque fluctuation can be reduced.
[0030]
In addition, with the above configuration, as shown in FIGS. 5 to 8, the rotary tiller 2 moves up and down substantially in parallel between the ground contact position and the standard tillage position, and from the middle ascending position to the highest ascending position, toward the tractor 1 side. Lifted up to get closer. As a result, even when the rotary cultivator 2 is closer to the tractor 1 side as compared with the conventional one, the position when the rotary cultivator 2 is raised can be taken higher, so that headland turning and the like can be performed. The turning range of the tractor can be made small, and the unstable running of the tractor due to the overhang weight effect during turning / running can be suppressed. Further, the front-rear balance between the tractor 1 and the rotary cultivator 2 is good, The effect that the hydraulic pressure (the lifting force of the rotary tiller 2) is small is required.
[0031]
Further, the PIC shaft 16 is located forward of a line segment F (a line segment passing through the axis of the upper connecting pin 28 and the axis of the lower connecting pin 30) passing through the work implement upper mounting point P5 and the work implement lower mounting point P6. It is configured to enter.
The main frame 31 of the connecting frame 15 is slightly inclined forward.
Next, the work implement mounting operation will be described.
[0032]
1 and 2, a three-point link mechanism 3 is connected to the vehicle body 4 and a connection frame 15 is connected to the three-point link mechanism 3. Further, the lock member 42 is kept at the lock position (the position drawn by the solid line and the broken line in FIG. 4). In this state, the vehicle body 2 is moved backward with respect to the rotary tiller 2 placed while being held so as not to fall down on the ground, and the upper tiller 2 is connected to the upper part 38 of the connection frame 15 above the upper engagement portion 38. The tractor 1 is moved closer to the rotary cultivator 2 so that the pin 28 is located.
[0033]
Then, the work machine lifting / lowering device 5 is operated to raise the connection frame 15, the upper connection pin 28 is engaged with the upper engagement portion 38, and the connection frame 15 is further raised to lift the rotary tiller 2. Then, the rotary cultivator 2 moves slightly forward so as to rotate forward with the work implement mounting point P5 as a fulcrum, and the lower connection pin 30 of the rotary cultivator 2 pushes down the lock member 42 while lowering the connection frame 15. It engages with the joint 40.
[0034]
When the lower connecting pin 30 is engaged with the lower engaging portion 40, the locking member 42 rotates upward on the rear side by the urging force of the spring 43, and locks the lower connecting pin 30.
On the other hand, when the rotary tiller 2 is lifted and slightly moved forward, the PIC shaft 16 is automatically moved to the yoke 54 of the universal joint 52 in parallel with the engagement of the lower connection pin 30 with the lower engagement portion 40. Spline fit.
[0035]
As described above, the rotary tiller 2 is connected to the connection frame 15 as an inclined shape that moves forward as the rotary tiller 2 moves upward.
In order to remove the rotary cultivator 2 from the tractor 1, the rotary cultivator 2 is raised, and the operation lever 48 of the release means 44 is tilted forward to a position shown by a virtual line in FIG. At this time, since the operation lever 48 is located on the front side of the connection frame 15, there is an advantage that the operation lever 48 can be easily operated from the driver side on the tractor 1.
[0036]
In the above configuration, when raising the rotary cultivator 2, the drive shaft 50 breaks around the front joint portion. However, as described above, if the raised position of the rotary cultivator 2 is set high, the drive shaft 50 The increase in the angle of rotation of the drive shaft 50 due to an increase in the angle of bending on the front side (the angle formed by the transmission shaft 53 and the PTO shaft 49) increases, and the load is not applied to the tilling unit 22 at the time of ascent. Although noise sometimes increases, in the above-described embodiment, since the constant velocity universal joint 51 is employed on the front side of the drive shaft 50, noise caused by fluctuations in the rotational angular velocity can be prevented.
[0037]
【The invention's effect】
According to the present invention, for example, at the time of headland turning or running on a road, when the work machine is raised, the work machine is lifted so as to approach the tractor, and the ground height of the work machine can be set high. In the case where the working machine is mounted on the tractor via the standard three-point link mechanism, even if the working machine is mounted close to the tractor, when the working machine is raised, the ground clearance of the working machine is raised. Can be secured at a sufficient height, and the implement can be approached to the tractor, so that the front-rear balance between the tractor and the implement can be improved, the range required for turning can be reduced, Lifting force can be reduced.
[0038]
Further, in side view, the angle formed by the line segment passing through the tractor-side connection point and the work machine-side connection point of the top link and the line segment passing through the tractor-side connection point and the work machine-side connection point of the lower link are equal to each other. By configuring so that the joint of the drive shaft connected to the PTO shaft is located on or near the line, the fluctuation of the bending angle of the drive shaft on the connection side with the PIC shaft can be reduced when the work machine is raised and lowered. Therefore, the working machine can be raised and lowered in a state where the bending angle of the drive shaft on the connection side with the PIC shaft is small.
[Brief description of the drawings]
FIG. 1 is a side view of a main part showing a connection structure between a tractor and a working machine.
FIG. 2 is an overall side view showing a connection structure between a tractor and a working machine.
FIG. 3 is a front view of a connection frame.
FIG. 4 is a side view of a work machine connecting portion.
FIG. 5 is a side view of the working machine in a grounded state.
FIG. 6 is a side view of the working machine at the time of standard tilling.
FIG. 7 is a side view of the working machine at the time of intermediate lifting.
FIG. 8 is a side view of the working machine when it is at its highest position.
FIG. 9 is a side view showing a conventional connection structure between a tractor and a working machine.
[Explanation of symbols]
2 Rotary tiller (working machine)
4 Body 7 Top link 8 Lower link 15 Connecting frame 16 PIC shaft 32 Upper connecting body 48 Operating lever 49 PTO shaft 50 Drive shaft 51 Conformal universal joint P1 Tractor side connection point P2 Tractor side connection point P3 Work implement side connection point P4 Work Machine side connection point P5 Work machine upper mounting point P6 Work machine lower mounting point A Line segment B Line segment C Line segment F Line segment θ1 Interior angle θ2 Interior angle θ3 Interior angle

Claims

A three-point link mechanism (3) including a top link (7) and a pair of left and right lower links (8) is connected to a rear portion of the vehicle body (4), and a connecting frame is connected to a rear end of the three-point link mechanism (3). (15) is connected to the connection frame (15) by a mounting point (P5) on the working machine and a mounting point (P6) below the working machine located below the mounting point (P5) on the working machine. It is configured so that a rotary tiller (2) can be attached,
Work in which the PTO shaft (49) of the vehicle body (4) and the PIC shaft (16) of the rotary tiller (2) are connected to the constant velocity universal joint (51) connected to the PTO shaft (49) and the PIC shaft. A drive shaft (50) having a machine-side universal joint (52) ,
The three-point link mechanism (3) is configured such that when the rotary cultivator (2) rises from the ground contact state, the trajectory of the work implement side connection point (P3) of the top link (7) is lower than the work implement of the lower link (8). A standard three-point link mechanism that passes outside the trajectory of the side connection point (P4) and the tractor side connection point (P1) of the top link (7) is located above the PTO shaft (49);
In the range from the position of the rotary tiller (2) at the time of standard tillage to the highest position, the top link (7 ) is set so that the bending angle of the universal joint (52) of the work implement on the drive shaft (50) is reduced. ) Are shorter than the length of the lower link (8), and the tractor-side connection point (P1) and the work implement-side connection point (P1) of the top link (7) are in contact with the rotary cultivator (2) in a ground contact state and in a side view. The line segment (A) passing through P3) is connected to the tractor-side connection point (P2) of the lower link (8) and the line segment (B) passing through the work implement-side connection point (P4 ). The tractor-side connection point (P1) of the top link (7) passes just before the tractor-side connection point (P2), and is located substantially directly above the joint between the PTO shaft (49) and the drive shaft (50). So that it slopes down And, in a side view, the line segment (A) passing through the tractor-side coupling point of the top link (7) (P1) and the working machine side connection point (P3), the tractor-side coupling point of the lower link (8) (P2 ) And a drive shaft (50) connected to the PTO shaft (49) on an approximately bisector (E) of an angle (θ1) formed by a line (B) passing through the work implement side connection point (P4). Position the constant velocity universal joint (51)
In a side view, the PIC shaft (16) of the rotary cultivator (2) is mounted on the work implement such that the PIC shaft (16) is located above the work implement side connection point (P4) of the lower link (8). A connection structure between a tractor and a work implement, wherein the tractor and the work implement are configured to enter forward of an imaginary line (F) connecting the point (P5) and the work implement lower attachment point (P6).

The upper link (32) of the connecting frame (15) connecting the rear ends of the top links (7) is inclined so as to move forward as it goes upward. A connection structure between the tractor and the working machine according to 1.

The distal end of the PIC shaft (16), the work machine side connection point (P4) of the lower link (8), and the work machine lower attachment point (P6) are triangularly arranged in a side view, and the PIC shaft (16) The connecting structure between a tractor and a working machine according to claim 1 or 2, wherein the distal end is located directly above the working machine-side connection point (P4) of the lower link (8).

The connecting structure between a tractor and a working machine according to claim 3, wherein the tractor-side connection point (P2) of the lower link (8) is located on the front side of the PTO shaft (49).

The operation lever (48) for unlocking the work implement lower attachment point (P6) of the connection frame (15) to which the rotary tiller (2) is mounted is disposed on the front side of the connection frame (15). A connecting structure between a tractor and a working machine according to claim 3 or 4, wherein:

The bend angle of the universal joint (52) on the work implement side of the drive shaft (50) is within a range from the position at the time of standard tilling of the rotary cultivator (2) to the time of the highest tilling. The connection structure between a tractor and a working machine according to any one of claims 1 to 5, wherein the angle is set to 10 ° .