Manufacturing method of rectangular wire, rectangular wire, and coating die

Abstract

To provide a rectangular wire configured so that a thickness of an insulation film covering a flat part of a conductor is not too thick and a thickness of an insulation film covering corner parts of the conductor is sufficiently thick.SOLUTION: A rectangular wire manufacturing method comprises: a first step of applying an insulation coating material to a circumference of a conductor; a second step of making a coating die pass on the conductor whose circumference coated with the insulation coating material; and a third step of forming a film of the insulation coating material to form an insulation film. A shape of a cross section perpendicular to a longitudinal direction of the conductor is a nearly-quadrangular shape in which four corner parts are rounded. Viscosity at 25°C of the insulation coating material is 5 Pa s or more. The coating die has an opening part formed in a nearly- quadrangular shape in which four corner parts are rounded, where vertical and lateral lengths of the opening part are longer than vertical and lateral lengths of the shape of the cross section of the conductor, and a radius Rd of the rounding of the corner part thereof is smaller than a radius Rc of the rounding of the corner part of the conductor.SELECTED DRAWING: Figure 1

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