| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic driving device capable of preventing the occurrence of cavitation and the reduction of brake capability even when connecting it with a brake cylinder. SOLUTION: In the hydraulic driving device constituted such that a counterbalance valve 3 is provided on the halfway of each main circuit in which a hydraulic source and a hydraulic motor M are mutually connected so as to switch freely, the counterbalance valve is provided with discharge passages 10, 11 opened and closed in the discharge side main circuit and a check valve provided on the halfway of a discharge passage, branch passages 21, 22 are provided on the upstream side of the check valve, a high pressure selection valve 4 allowing a flow of oil from the return side main circuit is provided on the halfway of return circuits 23, 24 connected with the return side main circuit, a bypass circuit is connected with the downstream side of the high pressure selection valve so as to open and close freely, and the other end is selectively opened and closed in the branch passage, the counterbalance valve is inserted into a valve hole 40 of a valve body, and the bypass circuit and the branch circuit are opened and closed in accordance with stroke of the counterbalance valve through a land groove 60 formed at inner periphery of the valve hole and having an arbitrary width.
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