A winding overhang machining method includes: cutting off corners of tip portions of conductors to form welding surfaces which are angled with respect to axes of the respective conductors; exerting a pushing force on each of the conductors, which have been inserted through an iron core so as to protrude out of the iron core, to form a bend in a base portion of the conductor so that the welding surfaces of two of the bent conductors to be connected together become contiguous and form a welding line; and connecting the two conductors together by performing laser welding on the welding surfaces. With this arrangement, a winding overhang structure can be obtained by processing the tip portions of the conductors with pushing forces but not drag forces.

A winding overhang machining method includes: cutting off corners of tip portions of conductors to form welding surfaces which are angled with respect to axes of the respective conductors; exerting a pushing force on each of the conductors, which have been inserted through an iron core so as to protrude out of the iron core, to form a bend in a base portion of the conductor so that the welding surfaces of two of the bent conductors to be connected together become contiguous and form a welding line; and connecting the two conductors together by performing laser welding on the welding surfaces. With this arrangement, a winding overhang structure can be obtained by processing the tip portions of the conductors with pushing forces but not drag forces.

A disc spring manufacturing method is a method for manufacturing a disc spring including a spring body formed into an annular shape and having an outer circumferential surface, an inner circumferential surface, an outer circumferential edge, and an inner circumferential edge, and includes applying a compressive residual stress to at least an outer end portion in the radial direction on the inner circumferential surface by relatively rotating a support body supporting at least the outer end portion in the radial direction on the inner circumferential surface and the spring body around a center axis line of the spring body while the support body and the spring body are brought into sliding contact with each other in a state in which a compressive force in an axial direction along the center axis line is applied to the spring body using the support body.

A disc spring manufacturing method is a method for manufacturing a disc spring including a spring body formed into an annular shape and having an outer circumferential surface, an inner circumferential surface, an outer circumferential edge, and an inner circumferential edge, and includes applying a compressive residual stress to at least an outer end portion in the radial direction on the inner circumferential surface by relatively rotating a support body supporting at least the outer end portion in the radial direction on the inner circumferential surface and the spring body around a center axis line of the spring body while the support body and the spring body are brought into sliding contact with each other in a state in which a compressive force in an axial direction along the center axis line is applied to the spring body using the support body.

A pre-tightening disc spring that includes a disc-shaped body formed with a central hole and having opposite first and second contact sides in a thickness direction. The disc-shaped body being a rotation solid formed by rotating a radial section about a central rotation axis by 360 degrees The central rotation axis coinciding with a central axis of the central hole The radial section having a first line segment and an opposing second line segment The first contact side being defined by rotating the first line segment, the second contact side being defined by rotating the second line segment, and a medium-diameter axis being defined to passing a mid-point of the second line segment and extending normally relative to the second line segment The the radial section being mirror-symmetrical relative to the medium-diameter axis.

A pre-tightening disc spring that includes a disc-shaped body formed with a central hole and having opposite first and second contact sides in a thickness direction. The disc-shaped body being a rotation solid formed by rotating a radial section about a central rotation axis by 360 degrees The central rotation axis coinciding with a central axis of the central hole The radial section having a first line segment and an opposing second line segment The first contact side being defined by rotating the first line segment, the second contact side being defined by rotating the second line segment, and a medium-diameter axis being defined to passing a mid-point of the second line segment and extending normally relative to the second line segment The the radial section being mirror-symmetrical relative to the medium-diameter axis.