PROBLEM TO BE SOLVED: To prevent a reaping portion lifting and lowering controller from digging into ground by means of chassis horizontal control output during reaping work.SOLUTION: In a combine harvester, a lifting and lowering mechanism for independently lifting and lowering each of right and left traveling devices (10) is arranged in each of a pair of the right and left traveling devices (10) supporting a chassis (11) a front reaping device (13) is arranged in the front portion of the chassis (11) so as to be freely lifted and lowered by means of a reaping portion lifting and lowering cylinder (19) a ground height sensor (25) for detecting the ground height of the front reaping device (13) at a plurality of points in a reaping width direction is arranged and the lifting and lowering mechanisms of the traveling devices (10) are controlled on the basis of the ground heights detected by the ground height sensor (25) in such a manner as to keep the front reaping device (13) to a predetermined ground height. The combine harvester has a constitution that a horizontal control command to the lifting and lowering mechanisms of the travelling devices (10) is stopped when a ground height detected by the ground height sensor (25) is equal to or lower than a predetermined lower limit height.COPYRIGHT: (C)2012,JPO&INPIT【課題】収穫作業中の車台水平制御出力によって、刈取昇降制御装置が地面に突っ込むことを防止する。【解決手段】車台(11)を支持する左右一対の走行装置(10)に、該走行装置(10)を左右独立して昇降させる昇降機構を設け、車台(11)の前部には刈取前処理装置(13)を刈取昇降シリンダ(19)で昇降自在に設け、該刈取前処理装置(13)の地上高を刈幅方向の複数個所で検出する接地高さセンサ(25)を設け、該接地高さセンサ(25)で検出された地上高に基づいて走行装置(10)の昇降機構を制御して刈取前処理装置(13)を所定の地上高に維持するコンバインにおいて、接地高さセンサ(25)で検出された地上高が予め設定された下限高さ以下となった場合に、走行装置(10)の昇降機構への水平制御指令を停止する構成とする。【選択図】図4
