| 摘要 |
<p>PURPOSE:To permit a piston to be switched to the advance cycle in operation cycle by generating a necessary operation hydraulic pressure in the retreat cycle of the piston, in a controller for a hydraulic cylinder which is used for a high-speed press, breaker, box nailing machine, etc. CONSTITUTION:In the reciprocating operation of a piston 2, air flows into a closed chamber 28 through a check valve 30, when a piston advances leftward and the liquid discharged from the closed chamber 28 during rightward movement is discharged into the atmosphere through a relief valve 31, and the pressure in the closed chamber 28 becomes the set pressure of the relief valve 31. When the piston advances rightward, the pressure of the working liquid supplied from a liquid pressure source 5 becomes the pressure corresponding to the set pressure of the relief valve 31, and the time for increasing pressure at the top dead center of the piston becomes zero, and when the piston reaches the top dead center, a 3-port-2-position selector valve 8 is switched to the position B, and the pressure corresponding to the set pressure of the relief valve 31 is introduced into a hydraulic chamber 6, and the piston 21 is applied a high pressure from the start of the leftward movement. When the piston moves leftward, the working liquid having a high pressure is discharged from an accumulator 36, and therefore, the energy of the piston is increased furthermore.</p> |
