| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To accumulate high-pressurized oil which can be applied to a high load work, when potential energy possessed by a vertically moving working portion is collected and accumulated in an accumulator and use the accumulated pressurized oil of the accumulator to various hydraulic actuators. <P>SOLUTION: A hydraulic system in a utility machine includes a unload valve 41 capable of being opened/closed for allowing pressurized oil in a head-side oil chamber 8a of an oil tank 12 of a first boom cylinder 8, i.e., one of a pair of the first and a second boom cylinders 8, 9, for lifting the working portion 4, and the weight of the working portion 4 is held by pressure of a head-side oil chamber 9a of the second boom cylinder 9 by opening the unload valve 41, when the working portion 4 is lowered. The system further includes an accumulator 59 and a converging oil path 16; the accumulator 59 accumulates and pressurizes discharged oil from the head-side oil chamber 9a of the second boom cylinder 9, when the working portion 4 is lowered; and the converging oil passage allows the accumulated pressurized oil of the accumulator to join with a discharge line 15 of a main pump 10. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
