| 摘要 |
PROBLEM TO BE SOLVED: To solve problems wherein sufficient joining strength cannot be secured when dispersion is caused in the joining strength of an insulating member and a metallic joining member as a result that a brazing material does not uniformly flow in clearance since the clearance of a mutually fitting part of both becomes large by a difference in a thermal expansion coefficient when brazing the insulating member and the metallic joining member, and airtightness cannot be maintained since a crack is caused in the brazing material. SOLUTION: Annular conductive members 13 having an opening 12a almost concentric with a through hole 11a in a central part, joining the cap-shaped metallic joining member 12 by allowing an inside surface to abut to an inclined face 11b, and having an opening 13a almost concentric with a through hole 11a in a central part on the periphery of the opening 12a of the metallic joining member 12, are joined to both end parts of the cylindrical insulating member 11 having the through hole 11a in the shaft direction, and having in both end parts the inclined face 11b having an outside diameter respectively gradually reduced toward an end surface. |
