| 摘要 |
<P>PROBLEM TO BE SOLVED: To efficiently supply pressure oil from a third pump so as to improve work efficiency of a construction machine by combining it with a first line to which pressure oil from a first pump is supplied, and a second line to which pressure oil from a second pump is supplied. <P>SOLUTION: In a first combined flow passage 38, pressure oil from the third pump 13 can be supplied to a first unloading passage 31 in the first line. In a second combined flow passage 39, pressure oil from the third pump 13 can be supplied to a second supply passage 34 in the second line. In a discharge passage 40, a restrictor is formed, and the first combined flow passage 38, the second combined flow passage 39, and a tank are connected. A combined flow change-over valve 30 comprises a communication position 42 for discharging pressure oil from the third pump 30 through the discharge passage 40 to the tank, and a limiting position 43 to disconnect the discharge passage 40 or limit discharge flow to the tank from the communication position 42. When prescribed two-way change-over valves 25 and 26 in the second line are operated, the combined flow change-over valve 30 is changed from the communication position 42 to the limit position 43. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
