HYDRAULIC DRIVE DEVICE OF INDUSTRIAL VEHICLE

• Main Authors: MATSUO TSUTOMU, UEDA SUKENORI, UNO MINESHI, YOKOMACHI NAOYA
• Format: Patent
• Language: English; Japanese
• Published: 30.05.2019
• Subjects: HAULING; HOISTING; HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDEDFOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCEDIRECTLY TO THE SURFACE OF A LOAD; LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS; LIFTING; MOTOR VEHICLES; PERFORMING OPERATIONS; TRAILERS; TRANSPORTING

To provide a hydraulic drive device of an industrial vehicle which can prevent an operator from feeling that a steering wheel is stuck for a moment when conducting K-turn operation of the steering wheel.SOLUTION: A hydraulic drive device 1 includes: a capacity control valve 4 which controls a variable capacity pump 3; a PS valve 6 disposed between the variable capacity pump 3 and a PS cylinder 5; a lift valve 29 disposed between the variable capacity pump 3 and a lift cylinder 7; hydraulic oil passages 10, 11 connecting the variable capacity pump 3 to the PS valve 6; hydraulic oil passages 10, 31 connecting the variable capacity pump 3 to the lift valve 29; and pilot lines 33, 18 connecting the lift valve 29 to the capacity control valve 4. A spool 35 of the lift valve 29 is provided with a groove part 37 forming a communication passage 36 which allows communication between the hydraulic oil passage 31 and the pilot line 33 at a neutral position 29a of the lift valve 29 when the PS valve 6 is at the neutral position.SELECTED DRAWING: Figure 2 【課題】運転者がステアリングホイールの切り返し操作を行う際に感じる引っ掛かりを防止す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、可変容量ポンプ３を制御する容量制御弁４と、可変容量ポンプ３とＰＳシリンダ５との間に配設されたＰＳバルブ６と、可変容量ポンプ３とリフトシリンダ７との間に配設されたリフトバルブ２９と、可変容量ポンプ３とＰＳバルブ６とを接続する作動油流路１０，１１と、可変容量ポンプ３とリフトバルブ２９とを接続する作動油流路１０，３１と、リフトバルブ２９と容量制御弁４とを接続するパイロットライン３３，１８とを備え、リフトバルブ２９のスプール３５には、ＰＳバルブ６が中立位置にあるときに、リフトバルブ２９の中立位置２９ａにおいて作動油流路３１とパイロットライン３３とを連通させる連通路３６を構成する溝部３７が設けられている。【選択図】図２