| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic shovel having simple construction for permitting the removal of air and actualizing good responsiveness of an actuator. SOLUTION: In a duct 93, a duct 71 is provided for communicating the duct 93 with an operating oil tank 51. A restrictor 72 is provided in the duct 71 to form a duct 7 with the restrictor. When air is trapped between the operating oil tank 51 and a hydraulic pump 52, the hydraulic pump 52 is driven to exhaust air from the duct 7 with the restrictor to the operating oil tank 51 and remove the air from a hydraulic circuit 5. By removing the air, resistance with the restrictor 72 is increased to make operating oil flow from a pilot pump 522 to a PPC valve 61. The simple construction with the duct 7 with the restrictor permits the removal of air, and so the operating oil from which the air is removed is originally supplied to the hydraulic cylinder 44 to actualize good responsiveness of the hydraulic cylinder 44. COPYRIGHT: (C)2006,JPO&NCIPI
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