A filler tube, which is capable of satisfying required functions suitably in compliance with the bellows and non-bellows cylindrical base while securing weld strength and fuel-permeation resistance property in the weld face, is provided. A filler tube includes a non-bellows cylindrical base with a total thickness of from 2 to 4 mm, a bellows with a total thickness of from 0.5 to 3 mm, and a flange having a total thickness of from 3.5 to 5 mm, and including an end face to be welded to a fuel tank. The non-bellows cylindrical base, the bellows, and the flange include inner layers formed so as to have a thickness accounting for from 40 to 60% of the total thicknesses, and formed of high-density polyethylene (or HDPE) serving as the major constituent, intermediate layers exhibiting fuel-permeation resistance property, and outer layers protecting the intermediate layers.

Provided are a resin filler tube capable of facilitating manufacture and ensuring rigidity in a bent tube portion, and a manufacturing method thereof. A resin filler tube connects an oil filling port and a fuel tank and includes straight tube portions and bent tube portions. The bent tube portions include a bellows-shaped bent inner portion in which hill portions and valley portions are continuous, and a bent outer portion which is formed by a non-bellows-shaped smooth surface. The valley portion of the bent inner portion has a linear outer peripheral surface parallel to a center line of the bent tube portions in a state in which the bent tube portions are in a straight tubular shape, and the linear outer peripheral surface of the valley portions is formed in an entire circumferential range in which the hill portions are formed.

A filler tube, which is capable of satisfying required functions suitably in compliance with the bellows and non-bellows cylindrical base while securing weld strength and fuel-permeation resistance property in the weld face, is provided. A filler tube includes a non-bellows cylindrical base with a total thickness of from 2 to 4 mm, a bellows with a total thickness of from 0.5 to 3 mm, and a flange having a total thickness of from 3.5 to 5 mm, and including an end face to be welded to a fuel tank. The non-bellows cylindrical base, the bellows, and the flange include inner layers formed so as to have a thickness accounting for from 40 to 60% of the total thicknesses, and formed of high-density polyethylene (or HDPE) serving as the major constituent, intermediate layers exhibiting fuel-permeation resistance property, and outer layers protecting the intermediate layers.

A filler tube including a cylindrical body and flange is manufactured using a cylindrical workpiece. A material forms an outermost layer in the cylindrical body and flange of the cylindrical workpiece. Dividable molds move at a first speed upon adhering the cylindrical workpiece onto the site for forming the cylindrical body, thereby giving the cylindrical body a predetermined diametrical thickness; and then move at a second speed being slower than the first speed upon adhering the cylindrical workpiece onto the other site for forming the flange, thereby filling up the flange with the material and other materials for forming the flange over a diametrical range to be welded onto the fuel tank while making the diametrical thickness of the flange greater than that of the cylindrical body.

An insulating coated wire includes a center conductor and an insulating coating. The insulating coating has a bending auxiliary section in which the thickness of the insulating coating is smaller than that of the other portion, and that has a shape in which at least a part thereof protrudes outward in the radial direction. The bending auxiliary section has a shape that facilitates bending of the insulating coated wire by elongation deformation thereof. This insulating coated wire can be manufactured by arranging, on the circumference of an insulating coated wire material, a metal mold that has the inner surface including the section having a shape protruding outward in the radial direction, and forming the bending auxiliary section in the shape along the inner surface of the metal mold by heating the insulating coating within the metal mold and generating a pressure difference between inside and outside of the insulating coating.