| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a hydraulic control circuit for a construction machine provided with a regenerative circuit for more smoothly moving an arm body. <P>SOLUTION: The hydraulic control circuit 100 includes: a regenerative valve 55 switching between a switching position R1 or R2 allowing flow of pressure oil from a rod chamber to a bottom chamber and a switching position R3 prohibiting flow of the pressure oil from the rod chamber to the bottom chamber; a pressure sensor 62 detecting pressure in the bottom chamber; and a regenerative circuit control means controlling switching of the regenerative valve 55. The regenerative circuit control means keeps the regenerative valve 55 at the switching position R3 when the regenerative valve 55 is located at the switching position R3 and the pressure in the bottom chamber exceeds the regeneration pass-up pressure, and switches the regenerative valve 55 to the switching position R3 when the regenerative valve 55 is located at the switching position R1 or R2, and the pressure in the bottom chamber exceeds the regeneration stop pressure that is higher than the regeneration pass-up pressure. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
