| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize hydraulic equipment, to use the general-purpose equipment and to realize a control for making compressive force constant by controlling pilot pressure oil of small pressure by small flow rate without the necessity of controlling large flow rate and large pressure. SOLUTION: Load pressure of a first hydraulic cylinder 11 for pushing is applied to a pilot port 8d of a switching valve 8 via an oil path 60b and an oil path 60a. Pilot pressure oil to be inputted into an operation valve 1 to drive the first hydraulic cylinder 11 for pushing is supplied to the switching valve 8 via an oil path 60. When load pressure of the first hydraulic cylinder 11 for pushing becomes above a prescribed value in this state, the switching valve 8 is switched to a position 8b to open the oil path 60. Therefore, pilot pressure oil to drive the first hydraulic cylinder 11 for pushing is led to a pilot port 3d of an operation valve 3 for retreating via the oil path 60, the switching valve 8 and an oil path 40b. Therefore, the operation valve 3 for retreating moves to a position 3b side. Because the operation valve 3 for retreating moves to the position 3b side, a panel 15 for retreating moves in a direction away from a slide panel 14, that is, the panel 15 moves in a direction that volume of a compression chamber 16 is increased.
|
