| 摘要 |
(Problem to be solved) The present invention reduces a breakdown possibility of an insulation body by restraining the lowering of a durability of a connection part. (Solution) An insulation body includes a first part, a second part, and an intermediate part. The first part is a part that accommodates a tip end of a terminal electrode and has a first inner diameter. The second part is a part that is disposed on the rear side of the first part and has a second inner diameter larger than the first inner diameter. The intermediate part is a part disposed between the first part and the second part. The terminal electrode includes a rough surface that has at least one of one or more convex parts and one or more concave parts on an outer peripheral surface thereof. The Vickers hardness of a part on the rear side of the rough surface of the terminal electrode, which is disposed in a through-hole, is equal to or greater than 200 Hv and equal to or smaller than 320 Hv. A first ratio that is a ratio of an outer diameter of the rough surface of the first part to the first diameter is equal to or greater than 0.90. A second ratio that is a ratio of the first inner diameter to the second diameter is equal to or greater than 0.80 and equal to or smaller than 0.98. |
