PROBLEM TO BE SOLVED: To provide a controller for lifting and lowering of an implement of an agricultural work vehicle designed to stably perform sufficient deceleration to the lowering side with an inexpensive motor.SOLUTION: The controller 60 for lifting and lowering of the implement of the agricultural work vehicle 1 is equipped with a hydraulic cylinder 6 for lifting and lowering the implement 14, a position controlling valve 90 changing over oil supply of a hydraulic oil to the hydraulic cylinder 6 by operating a lifting and lowering operation means, a normally and reversibly rotatable electric motor 95 connected to an operation part of the position controlling valve 90 and further a means 85 for detecting the rotation position of an output shaft of the electric motor 95 therein. The implement 14 is freely liftably and lowerably controlled corresponding to the operation position of the electric motor 95. In the controller 60, the amount of output is variably controlled according to the deviation from the target stopped position of the motor 95. When the rotational speed of the motor 95 reaches a value not higher than the set value, a parameter predetermined for the deviation is changed and controlled. A relationship parameter between the whole deviation and the output is recalculated by using the parameter when the operation speed reaches the value not higher than the set value as the minimum output.COPYRIGHT: (C)2007,JPO&INPIT【課題】安価なモータを用いて下降側に十分な減速が安定して行われることを可能にする農用作業車の昇降制御機構を提供する。【解決手段】作業機14を昇降する油圧シリンダ6と、該油圧シリンダ6への圧油の送油を昇降操作手段の操作により切り換えるポジション制御バルブ90と、該ポジション制御バルブ90の操作部に連繋された正逆回転可能な電動モータ95を備え、該モータ95にはその出力軸の回転位置を検出する手段85を備え、作業機14を前記電動モータ95の操作位置に対応して昇降自在に制御する作業車1の作業機昇降制御装置60において、前記モータ95の目標停止位置からの偏差に応じて出力量を可変に制御し、前記モータ95の回転速度が設定値以下に達したならば偏差に対して予め定められたパラメータを変更制御し、動作速度が設定値以下に達したときのパラメータを最小出力として、全体の偏差と出力の関係パラメータを再計算させる。【選択図】図13
