| 摘要 |
PURPOSE:To suppress the dispersion of fracture load at the fragile part, by forming a fragile part by a multiple number of V-shaped grooves which are concentrically formed on the upper and lower surfaces of a flange. CONSTITUTION:A fuel cap 11 is equipped with an approximately cylindrical shaped cap 12 and a lid 19 to cover the top of the cap 12. On the upper surface of the cap 12, at an outer area in the radial direction, 2 each of V-shaped grooves 16A, 16B with a cross section of V-shape are concentrically formed along the circumferential direction of the cap 12; on the lower surface of the cap 12, being adjacent to the upper surface V-shaped grooves 16A, 16B, 2 each of V-shaped grooves 17A, 17B with a cross section of V-shape are concentrically formed along the circumferential direction of the cap 12. By these upper surface V-shaped grooves 16A, 16B and lower surface V-shaped grooves 17A, 17B, a fragile part 18, which is easy to break at a prescribed time, is formed. By this arrangement, when an external force is added to a flange 15 through the lid 19 from various directions, the fragile part 18 can be broken with a small fracture load; and the dispersion of the fracture load can be suppressed. |
