Method for manufacturing bottom valve seat

A method for manufacturing a bottom valve seat for use in a hydraulic damper, in which projections defining fluid passages are provided on a lower end cover thereof, comprising the steps of:

• punching out a circular blank from a flat plate of a given thickness into a circular blank having given dimensions;
• drawing said blank into a cup-shape having a circumferential flange portion;
• forming a cylindrical wall for the cup-shaped work thus provided, said wall having a given length;
• pressing the central portion of the bottom portion of said cup-shaped work downwards or internally, thereby forming an annular flat portion along the circumferential edge of said bottom portion;
• cutting said flange portion to desired dimensions;
• and
• after said forming and pressing steps, punching a through-hole in the bottom portion of said cup-shaped work;
• said flange portion being thereby formed to have a flat surface on the side opposite the bottom portion thereof, and said annular flat portion of said bottom portion being thereby formed to have a curvature along its inner circumferential edge for supporting a double-sheet valve.