a plurality of first punches and a plurality of second punches stacked to form a rotor core;

a plurality of openings provided in each of the plurality of first punches and the plurality of second punches along a circumferential direction of the rotor core, each of the plurality of openings having a V-shape that diverges along a respective radial axis away from a center axis of the rotor core, the plurality of openings dividing each of the plurality of first punches and the plurality of second punches into a rotor yoke and a plurality of pole caps, the plurality of pole caps arranged around an outer circumference of the rotor yoke, the plurality of openings extending in an axial direction of the rotor core to form a plurality of slots; and

a plurality of magnets arranged in the plurality of slots in a two-to-one correspondence,

wherein each of the plurality of first punches and each of the plurality of second punches comprises at least one connecting rib, each of the at least one connecting rib is disposed between adjacent two of the plurality of pole caps, and at least two of the plurality of openings of each of the plurality of second punches communicate with each other adjacent to one of the at least one connecting rib of the each of the plurality of second punches.