| 摘要 |
PURPOSE:To obtain choice of whether high damping force is to be generated or low damping force is to be generated and moreover reduce manufacturing cost by forming a plurality of port opening windows on both internal and external diameter sides on a valve seat and utilizing any either of the port opening windows. CONSTITUTION:A valve seat 13 is provided with two annular port opening windows 21 and 22 which are divided into two portions, internal diameter side and external diameter side, on a seat surface 13a of the seat 13. The top surface of a relief valve 14 is adjacent to the top part of frame parts 23 and 24 which form each annular port opening windows 21 and 22. The annular port opening window 21 on the internal dia. side is smaller in area than that 22 on the external dia. side. And by making ports 25 in either the port opening window 21 or the window 22, whether comparatively high damping force is to be generated or comparatively low damping force is to be generated can be selected at will. |
