Abstract: A protective ring with an annular shape that is formed of an elastic member and is mounted in an annular groove formed in a butt adhesion surface of a first cylindrical member and a second cylindrical member includes a band-shaped ring body and a ridge protruding from a center of an inner surface in a width direction and pressed against the annular groove. The ridge is continuously formed such that a cross section of the ridge is semicircular-shaped and has a smaller diameter than a width of the ring body, and the width of the ring body is larger than a thickness of the protective ring in a radius direction.

Abstract: An insulated electric wire and a method of producing the electric wire are provided. The insulated electric wire includes: a copper wire; and an insulating coating formed on a surface of the copper wire by an electrodeposition method. A cross section shape of the insulated electric wire including the insulating coating is in a hexagonal shape, a chamfered part that suppresses swelling of the insulating coating is formed on each corner part of a hexagonal cross section of the copper wire, a length of the chamfered part is ? to 1/20 of a length of a flat part of the hexagonal cross section, and a void ratio in a wound state is 5% or less.

Abstract: An insulated electric wire and a method of producing the electric wire are provided. The insulated electric wire includes: a copper wire; and an insulating coating formed on a surface of the copper wire by an electrodeposition method. A cross section shape of the insulated electric wire including the insulating coating is in a hexagonal shape, a chamfered part that suppresses swelling of the insulating coating is formed on each corner part of a hexagonal cross section of the copper wire, a length of the chamfered part is 1/3 to 1/20 of a length of a flat part of the hexagonal cross section, and a void ratio in a wound state is 5% or less.