| 摘要 |
PROBLEM TO BE SOLVED: To prevent occurrence of a junction where a portion other than the end of a glass tube is bonded to a glass wound portion, when welding the glass wound portion formed around an electrode lead rod to the end of the glass tube of a relatively small diameter.SOLUTION: In a fixing structure of an electrode lead rod, glass wound portions 22, 27 are formed around electrode lead rods 14, 18, and the ends of glass tubes 21, 26 are welded to the glass wound portions 22, 27. The longest distance A between the edges of the glass wound portions 22, 27 surrounded by the glass tubes 21, 26 and the edges on the inside of the glass tubes 21, 26 welded to the glass wound portions 22, 27 in the axial direction is 2 mm or less. The shortest distance B between the inner periphery of the glass tubes 21, 26 and the outer periphery of the glass wound portions 22, 27 in the radial direction is preferably 2 mm or less. |
