| 摘要 |
PROBLEM TO BE SOLVED: To provide an opening structure of a fuel tank made of a synthetic resin which has improved rigidity of the tank opening structure and excellent sealability and requires a reduced space for mounting.SOLUTION: In a tank opening structure of a fuel tank, a tank opening part comprises: a cylindrical part 11; an opening upper end part 13; and an opening screw part 14 that is formed on the outer surface of the cylindrical part 11. An engagement member 20 has an engagement upper part 21 and an engagement cylindrical part 22, and an engagement screw part 23 to be engaged in the opening screw part 14 is formed on the inner surface of the engagement cylindrical part 22. The tank opening part is composed of a material having a tensile strength of 20-40 Mpa, and the engagement member 20 is made of a material having a tensile strength of 40-100 Mpa. The width of the thread of the engagement screw part 23 of the engagement member 20 is 30-70% of the width of the lower end of the thread of the opening screw part 14. |
