Patent attributes
A filler pipe for suppressing swelling deformation caused by fuel, and a manufacturing method thereof. A resin filler pipe has a bellows section, including peaks and valleys, and an ordinary section, not including the bellows section, and is provided with at least inner layers, barrier layers, and outer layers. In the ordinary section, the inner layer is thinner than the outer layer, and the rate of increase in the proportion of the inner layer in the peaks of the bellows section with respect to the proportion of the inner layer in the ordinary section is equal to or less than the rate of increase in the proportion of the outer layer in the peaks of the bellows section with respect to the proportion of the outer layer in the ordinary section.
