Method for manufacturing motor core
A method for manufacturing a motor core includes a step of manufacturing a motor core by performing melt-cutting on an electrical steel sheet using heat input from a surface, the electrical steel sheet having an average thermal conductivity in depth positions from the surface to one-third depth of a sheet thickness lower than a thermal conductivity in a middle position in a sheet thickness direction by 30% or greater.
1. A method for manufacturing a motor core, comprising:
a step of manufacturing a motor core by performing melt-cutting on an electrical steel sheet using heat input from a surface, the electrical steel sheet having an average thermal conductivity in depth positions from the surface to one-third depth of a sheet thickness lower than a thermal conductivity in a middle position in a sheet thickness direction by 30% or greater.
2. The method for manufacturing a motor core according to claim 1 , wherein the sheet thickness of the electrical steel sheet is equal to or smaller than 0.20 mm.
3. The method for manufacturing a motor core according to claim 2 , wherein concentrations of Si, Al, and Mn in the depth positions from the surface to one-third depth of the sheet thickness of the electrical steel sheet satisfy a condition given in a following formula (1):
Al+Si≥10Mn (1).
4. The method for manufacturing a motor core according to claim 3 , wherein a concentration of each constituent for an entire sheet thickness of the electrical steel sheet is C: 0.01% or smaller, Si: 7% or smaller, Al: 4% or smaller, and Mn: 5% or smaller, in mass %.
5. The method for manufacturing a motor core according to claim 2 , wherein a concentration of each constituent for an entire sheet thickness of the electrical steel sheet is C: 0.01% or smaller, Si: 7% or smaller, Al: 4% or smaller, and Mn: 5% or smaller, in mass %.
6. The method for manufacturing a motor core according to claim 1 , wherein concentrations of Si, Al, and Mn in the depth positions from the surface to one-third depth of the sheet thickness of the electrical steel sheet satisfy a condition given in a following formula (1):
Al+Si≥10Mn (1).
7. The method for manufacturing a motor core according to claim 6 , wherein a concentration of each constituent for an entire sheet thickness of the electrical steel sheet is C: 0.01% or smaller, Si: 7% or smaller, Al: 4% or smaller, and Mn: 5% or smaller, in mass %.
8. The method for manufacturing a motor core according to claim 1 , wherein a concentration of each constituent for an entire sheet thickness of the electrical steel sheet is C: 0.01% or smaller, Si: 7% or smaller, Al: 4% or smaller, and Mn: 5% or smaller, in mass %.