CONSTRUCTION MACHINE HYDRAULIC DRIVE SYSTEM

• Main Authors: KINOSHITA ATSUSHI, MURAOKA HIDEYASU, OKASHIRO TAKASHI, NOSE TOMOMICHI, SAKAMOTO MORIYUKI
• Format: Patent
• Language: English; Japanese
• Published: 19.07.2018
• Subjects: BLASTING; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR; DREDGING; FIXED CONSTRUCTIONS; FLUID-PRESSURE ACTUATORS; FLUID-PRESSURE ACTUATORS, e.g. SERVO-MOTORS; FOUNDATIONS; HEATING; HYDRAULIC ENGINEERING; HYDRAULICS OR PNEUMATICS IN GENERAL; LIGHTING; MECHANICAL ENGINEERING; SOIL SHIFTING; SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; WEAPONS

PROBLEM TO BE SOLVED: To make it possible to prevent the swing-back phenomenon at a rotation stop without using a contrarotation prevention valve.SOLUTION: A construction machine hydraulic drive system comprises: a rotation motor 4; a rotation operating device for outputting a rotation operating signal according to an inclination angle of an operation lever 51; a rotation direction switching valve 3 shifting between a neutral position for blocking a pair of supply and exhaust lines and an actuating position for communication of one of the pair of supply and exhaust lines with a pump line and for communication of the other with a tank line; and a controller 6 for supplying a larger command current to the rotation direction switching valve as the rotation operating signal becomes larger. The controller 6 controls the rotation direction switching valve such that when the operation lever 51 of the rotation operating device is returned to a neutral state, the rotation direction switching valve shifts from the neutral position to the actuating position for communication of the supply and exhaust line on the exhaust side to the tank line at the rotation speed of the rotation body detected by a speed detector falling below a first threshold and that the rotation direction switching valve shifts from the actuating position to the neutral position at the rotation speed of the rotation body falling below a second threshold.SELECTED DRAWING: Figure 1 【課題】反転防止弁を用いずに旋回停止時の揺れ戻り現象を防止できるようにする。【解決手段】建設機械の油圧駆動システムは、旋回モータ４と、操作レバー５１の傾倒角に応じた旋回操作信号を出力する旋回操作装置と、一対の給排ラインをブロックする中立位置と、一対の給排ラインの一方をポンプライン、他方をタンクラインと連通する作動位置との間でシフトする旋回方向切換弁３と、旋回操作信号が大きくなるほど大きな指令電流を旋回方向切換弁へ送給する制御装置６と、を備え、制御装置６は、旋回操作装置の操作レバー５１が中立状態に戻された場合、速度検出器で検出される旋回体の旋回速度が第１閾値を下回ったときに、旋回方向切換弁が中立位置から排出側の給排ラインをタンクラインと連通する作動位置へシフトし、旋回体の旋回速度が第２閾値を下回ったときに、旋回方向切換弁が作動位置から中立位置へシフトするように、旋回方向切換弁を制御する。【選択図】図１