Rotor core, rotor, and electric motor

A rotor core, wherein

• a plurality of pairs of magnet slots extending in an axial direction of the rotor core are formed in the rotor core,
• the plurality of pairs of magnet slots are arranged at equal intervals in a circumferential direction of the rotor core in a radial cross-section of the rotor core,
• each pair of magnet slots of the plurality of pairs of magnet slots includes a first magnet slot which is inclined counterclockwise relative to a radius of the rotor core and a second magnet slot which is inclined clockwise relative to the radius of the rotor core,
• a plurality of holes extending in the axial direction of the rotor core are further formed between the first magnet slot and the second magnet slot in each pair of magnet slots,
• in the radial cross-section of the rotor core, each of the plurality of holes is constituted by an approximately isosceles triangle an apex angle of which faces a center of the rotor core and an arc protruding from a base of the isosceles triangle toward a radially outer side of the rotor core, and
• at least one portion of the arc in each of the plurality of holes in the radial cross-section of the rotor core is positioned on the radially outer side of the rotor core relative to a first line segment between a portion of the first magnet slot positioned at the outermost position of the rotor core and a portion of the second magnet slot positioned at the outermost position of the rotor core.