| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a seal member for a spark plug, and a spark plug, capable of obtaining enough axial tension even by a low clamping torque. Ž<P>SOLUTION: Of a cross section of a gasket 80 made of stainless steel of high rigidity to be mounted on the spark plug for M12 use, provided, the number of layers of plate materials at a site where the most layers of the plate materials overlap each other in an axis-line O direction is n, and a total of thicknesses of the layers at the most-overlapped part (a total thickness) is denoted by L, a thickness x of the gasket 80 as a whole satisfies: 1.1L≤x≤1.45L. Clamping torque increases as clamping of the spark plug progresses at its fitting, but, the gasket 80 first begins to generate elastic deformation, and, when it reaches the limit, generates plastic deformation. The above formula is satisfied at this point, so that, the plate materials themselves get adhered to each other during the elastic deformation, or soon after generation of the plastic deformation, which hardly gives rise to loss of the axial tension. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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