| 摘要 |
PURPOSE: To increase cushioning force by composing a flow through-hole formed on a cushion valve as a guide portion for a valve spring extending in an axial direction, at least partially closing the hole at both sides by valve discs, and supporting the valve discs by means of the valve springs. CONSTITUTION: When counter-current speed of fluid is low, namely, when motion speed of a piston rod 3 is low, valve bodies 9, 10 are arranged on the same plane as an end face 22 of a valve element 6 due to a valve spring 11 and closes the end face 22. In such a case, cushion oil flows through a groove 12, a circular margin 15 and a flow through-hole 6, while cushion action of a cushion valve is suppressed to minimum. When counter-current speed of the fluid is high, dynamic pressure is generated in front of a disc 9 or 10 in a motion direction of the rod 3. When the intensity of the spring 11 is specified, the disc 9 or 10 is respectively moved due to the dynamic pressure, while the flow through-hole 6 is substantially closed. Afterward, the oil is flowed through the groove 12, a radial groove 13 and the hole 6, for increasing flowing resistance. |
