PROBLEM TO BE SOLVED: To provide a fuel tank capable of preventing looseness of a cap while suppressing an increase in the number of components.SOLUTION: A fuel tank 1 comprises: a projection part 7 which is provided at a position different from a male screw part 4 of an outer peripheral part of a neck part 3 of a tank body 2, and projects outward in a radial direction of the neck part 3 and a plate spring 20 having a projection 22 which is fixed at a position different from a female screw part 14 of an inner peripheral part of a cap 10, and projects inward in a radial direction of the cap 10. The projection 22 rides over the projection part 7 when the cap 10 is rotated in a fastening direction D and screwed to the neck part 3. The projection part 7 restricts rotation in an opposite direction from the fastening direction D of the cap 10 by coming into contact with the projection 22.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT【課題】部品点数の増加を抑えつつ、キャップの緩みを防止することができる燃料タンクを提供する。【解決手段】燃料タンク1は、タンク本体2の首部3の外周部の雄ねじ部4とは異なる位置に設けられて、首部3の径方向外方に突出する突出部7と、キャップ10の内周部の雌ねじ部14とは異なる位置に固定されて、キャップ10の径方向内方に突出する突起22を有する板ばね20と、を備える。キャップ10が締付け方向Dに回転されて首部3にねじ込まれる際に突起22は突出部7を乗り越え、突出部7は、突起22に当接することでキャップ10の締付け方向Dとは逆方向の回転を規制するように構成される。【選択図】図1
