Field magneton

A field magneton constituting a rotating electric machine including an armature having an armature winding, and arranged radially facing the armature, comprising:

• a magnet having a plurality of magnetic poles with alternating polarities in a circumferential direction;
• and
• a field magneton core, wherein
• the field magneton is an embedded magnet type field magneton in which the magnet is housed in a magnet housing hole formed in the field magneton core,
• the magnet is oriented so that a direction of an axis of easy magnetization on a d-axis side, which is a magnetic pole center, is closer to a direction of the d-axis than the direction of the axis of easy magnetization on a q-axis side, which is a magnetic pole boundary,
• the magnet housing hole and the magnet extends lengthwise from the d-axis side toward the q-axis side,
• in the magnet, a coefficient of linear expansion in the direction of the axis of easy magnetization is positive and the coefficient of linear expansion in the direction perpendicular to the axis of easy magnetization is negative, and an absolute value of the coefficient of linear expansion in the direction perpendicular to the axis of easy magnetization is larger than the absolute value of the coefficient of linear expansion in the direction of the axis of easy magnetization,
• an amount of dimensional change in the longitudinal direction per unit temperature change in a d-axis portion of the magnet is referred to as Gd,
• an amount of dimensional change in the longitudinal direction per unit temperature change in a q-axis portion of the magnet is referred to as Gq, and
• a direction of the axis of easy magnetization on the d-axis side is closer to the direction of the d-axis side than the direction of the axis of easy magnetization on the q-axis side, and the magnet is oriented so as to satisfy Equation 2.
• 0.8≤|Gd/Gq|<1 (Equation 2).