| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a hydraulic drive system preventing accidental increase in operation speed of a hydraulic cylinder and increasing the operation speed of the hydraulic cylinder as necessary. <P>SOLUTION: A second differential circuit 24 and a second flow rate increase selector valve 23 are disposed on a hydraulic cylinder 4 side of the hydraulic circuit. The second differential circuit 24 increases the flow rate of hydraulic oil supplied from a hydraulic pressure supply source T, and the second flow rate increase selector valve 23 switched to connect the second differential circuit 24 to the hydraulic circuit when the flow rate of the hydraulic oil flowing in the hydraulic circuit exceeds a preset reference value. By switching operation of the first flow rate increase selector valve 21 to connect the first differential circuit 20 to the hydraulic circuit, the flow rate of the hydraulic fluid in the hydraulic circuit exceeds the reference value so that the second flow rate increase switching valve 23 is switched to connect the second differential circuit 24 to the hydraulic circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
