HYDRAULIC DRIVE DEVICE FOR INDUSTRIAL VEHICLE

To provide a hydraulic drive device for industrial vehicle capable of effectively operating a hydraulic cylinder, while achieving miniaturization of a hydraulic pump.SOLUTION: A hydraulic drive device 1 includes: a hydraulic oil supply flow passage 14 for connecting a main pump 8 and a lift cylinder 2; a switching valve 33 for switching between an open position 33b for communicating a discharge port 9b of a sub pump motor 9 and an accumulator 32 and a closed position 33c for cutting off the discharge port 9b and the accumulator 32; a switching valve 35 for switching between an open position 35b for communicating the discharge port 9b and a tank 7 and a closed position 35c for cutting off the discharge port 9b and the tank 7; a switching valve 37 for switching between an open position 37b for communicating the discharge port 9b and the hydraulic oil supply flow passage 14 and a closed position 37c for cutting off the discharge port 9b and the hydraulic oil supply flow passage 14; and a control unit 43 for controlling the switching valves 33, 35, 37 on the basis of an operation state of a lift operation lever 5.SELECTED DRAWING: Figure 1 【課題】油圧ポンプの小型化を図りつつ、油圧シリンダを効果的に動作させることができる産業車両の油圧駆動装置を提供する。【解決手段】油圧駆動装置１は、メインポンプ８とリフトシリンダ２とを接続する作動油供給流路１４と、サブポンプモータ９の吐出口９ｂ及びアキュムレータ３２を連通させる開位置３３ｂと吐出口９ｂ及びアキュムレータ３２を遮断する閉位置３３ｃとが切り換えられる切換弁３３と、吐出口９ｂ及びタンク７を連通させる開位置３５ｂと吐出口９ｂ及びタンク７を遮断する閉位置３５ｃとが切り換えられる切換弁３５と、吐出口９ｂ及び作動油供給流路１４を連通させる開位置３７ｂと吐出口９ｂ及び作動油供給流路１４を遮断する閉位置３７ｃとが切り換えられる切換弁３７と、リフト操作レバー５の操作状態に基づいて切換弁３３，３５，３７を制御する制御ユニット４３とを備える。【選択図】図１