| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a threaded member having a sealing member and a spark plug, capable of ensuring a crushing margin of a sufficient size while suppressing squeezing-out from a bulging portion when crushed. <P>SOLUTION: A gasket 100 has a spiral shape having a circumferential cross section in which one end portion 101 is on an outer side than another end portion 102. The circumferential cross section is composed of a first extending portion 110, a second extending portion 120, a third extending portion 130, a first connecting portion 140, a second connecting portion 150, and a third connecting portion 160. Where the height in an axis Q direction of the gasket 100 is h, the thickness at a part of the second extending portion 120 satisfying h/2 is t, the curvature radius of the first connecting portion 140 is r, the diametrical distance minimizing the second extending portion 120 is R2, and the diametrical distance maximizing the third extending portion 130 is R1, expressions of 2×t≤r≤(R1-R2)/2 and h≥(R1-R2) are satisfied. <P>COPYRIGHT: (C)2012,JPO&INPIT |
