| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a spark plug in which an annular packing used at an annular receiving shelf formed in a main body metal fitting for maintaining airtightness and supporting an annular abutting part of the tip of the tip side support shaft part, out of a cylindrical insulator inserted into a main body metal fitting, can be compressed and molded into a tapered shape without problem, even if reduction in diameter of the spark plug including the main body metal fitting is advanced. <P>SOLUTION: In a stage after a flat washer shaped packing 41 is disposed at an annular receiving shelf 36 and before fixing the insulator into a main body metal fitting 31, from the rear end side of the main body metal fitting 31, an upper die punch 200 is inserted which has an annular press molding surface 205 being a front end-facing surface formed into a tapered taper corresponding to the taper of the annular receiving shelf 36, and the flat washer shaped packing 41 is pressed by this press molding surface 205, thereby deformed into a taper shaped packing 41. <P>COPYRIGHT: (C)2012,JPO&INPIT |
