| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a hydraulic system for a backhoe, which can surely prevent the phenomenon that an operation of a ground working device is stopped once because the supply of pressure oil into a hydraulic cylinder for operating the ground working device is stopped once, when a control valve for a travel unit is operated in the use of the ground working device. <P>SOLUTION: This hydraulic system is equipped with an independent-travel working valve V17 which can switch between a working position 56 to supply pilot pressure to a first channel switching valve V12 and a nonworking position 57 not to supply the pilot pressure to the first channel switching valve V12. The independent-travel working valve V17, which is in the state of being switched to the nonworking position 57 during non-traveling, is switched to the working position 56 by the pilot pressure applied to a travel detecting circuit 54. Original pilot pressure from a fourth pump P4 on the upstream side of a throttle 53 for introducing the pressure oil is supplied to the first channel switching valve V12 in the working position 56. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
