PROBLEM TO BE SOLVED: To control a working implement not to be frequently lifted by disturbance factors even if a set excavation depth is shallow when the excavation depth is automatically retained at a set depth, in an excavation depth automatic controller for the working implement of a tractor towing the working implement which moves forward while excavating the ground.SOLUTION: The ground excavation depth H of the working implement 2 towed by the tractor 1 is set at an appropriate set ground excavation depth H0. The excavation depth automatic controller for the working implement of the tractor controls the working implement 2 in such a way that divergence of an actual ground excavation depth H is left uncontrolled for a fixed grace period T only if the actual ground excavation depth H is diverged from a permissible deflection range K of the set ground excavation depth H0, and in such a way that the grace period T is further extended when the set ground excavation depth H0 is shallow than when the depth is deep and the position of the working implement 2 is corrected to the set ground excavation depth H0 after the elapse of the grace period T.COPYRIGHT: (C)2012,JPO&INPIT【課題】本発明では、地面を掘りながら進行する作業機を牽引したトラクタの作業機掘り深さ自動制御装置において、掘り深さを自動的に設定深さに維持するに、設定掘り深さを浅くしても外乱要素によって作業機が頻繁に昇降しないように制御することを課題とする。【解決手段】トラクタ1で牽引する作業機2の対地掘り深さHを適宜の設定対地掘り深さH0に設定し、実際の対地掘り深さHが設定対地掘り深さH0の許容振れ幅Kからずれても一定の猶予時間Tだけそのずれを放置するよう制御し、設定対地掘り深さH0が浅い場合には深い場合よりも猶予時間Tを長くして、猶予時間Tの経過後に作業機2の位置を設定対地掘り深さH0に修正するように制御したことを特徴とするトラクタの作業機掘り深さ自動制御装置とした。【選択図】図4
