| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic driving device capable of driving a hydraulic motor by changing over the supply source of working fluid to a hydraulic motor by a simple hydraulic circuit constitution and a simple control constitution.SOLUTION: A hydraulic driving device includes: a first hydraulic pump 61 of variable displacement type which is driven by an engine E; a second hydraulic pump 62 of variable displacement type which is driven by an electric motor M; a hydraulic motor 16 which is rotary driven by receiving the oil supply; displacement control means 67, 68 for performing the variable displacement control of the first and second hydraulic pumps 61, 62; first oil passages 63, 64 which merge discharged oil from discharge ports of the first and second hydraulic pumps 61, 62, and make the merged discharged oil flow into an inflow port of the hydraulic motor 16; and second oil passages 65, 66 which branch outflow oil from the outflow port of the hydraulic motor 16, and make the branched outflow oil flow into inflow ports of the first and second hydraulic pumps 61, 62. |
