| 摘要 |
A filler cap for a fuel tank wherein, when a pressure increases in the fuel tank, the valve body moves upward so an upper peripheral edge part of the valve body may be contacted to a first surface of shoulder cylinder portion, thereby shutting down a connection between a second space of cylinder main body and a third space connected to atmosphere. When the pressure in the fuel tank exceeds a pressure for a deformation strength of the valve body, a central part of the valve body enters into the third space causing deformation to shorten the outer diameter thereof; in the peripheral part of the valve body a concave portion not contacted to a lower end of a third surface that forms the third space, and the second space and the third space are connected via a space of this concave portion to release excessive pressure. |
