Wound magnetic core manufacturing method and wound magnetic core

A method for manufacturing a non-circular wound magnetic core composed of a nano-crystallized soft magnetic alloy strip, the method comprising:

• a step of acquiring a multilayer body by winding a soft magnetic alloy strip that can undergo nano-crystallization around a bobbin;
• a step of nano-crystallizing the soft magnetic alloy strip that can undergo nano-crystallization by removing the bobbin from the multilayer body, and inserting a heat treatment inner peripheral jig on an inner peripheral side of the multilayer body, maintaining the multilayer body in a non-circular shape when viewed in the axial direction, and subjecting the multilayer body maintained in the non-circular shape to heat treatment;
• and
• a step of maintaining the nano-crystallized multilayer body in the non-circular shape using resin impregnation inner peripheral and outer peripheral jigs and impregnating a resin between the layers of the multilayer body, wherein a pressure applied when the resin is impregnated is equal to or greater than −0.05 MPa and equal to or less than 0 MPa with respect to atmospheric pressure, and
• wherein the resin impregnation inner peripheral and outer peripheral jigs are shaped so as to not contact at least one of the inner peripheral surface and the outer peripheral surface of the multilayer body at a part where the multilayer body has a degree of curvature that is equal to or greater than 0.02, wherein the degree of curvature is calculated based on a reciprocal of a curvature radius R (1/mm).