Rotor, motor and method of manufacturing the rotor

An inner rotor type motor, comprising:

• a rotor structured to rotate on a vertically extending center axis, the rotor comprising:
• a cylindrical rotor core comprising a magnetic material;
• a plurality of magnets provided on an outer circumferential surface of the rotor core;
• and
• a resin portion holding the rotor core and the magnets, the resin portion comprising an outer cover portion covering a radially outer side surface of the magnets,
• wherein the outer cover portion comprises:
• a groove portion recessed radially inward from a radially outer surface and extending in an axial direction;
• and
• a wall portion adjacent to the groove portion in a circumferential direction;
• a stator core formed of a magnetic material having a plurality of teeth which face an outer circumferential surface of the rotor in a radial direction;
• a conductive wire wound around the plurality of teeth;
• and
• a stator housing which is made of resin and covers at least a portion of the conductive wire and the stator core.

A method of manufacturing a rotor having a tube-shaped rotor core which is made of a magnetic material and has its center on a vertically extending center axis;

• a plurality of magnets which are provided on an outer circumferential surface of the rotor core;
• and a resin portion which holds the rotor core and the magnets,
• the method comprising:
• a) disposing the rotor core and the plurality of magnets in a cavity portion formed by a pair of upper and lower molds;
• b) pouring molten resin into the cavity portion;
• and
• c) forming the resin portion by solidifying the molten resin,
• wherein at least one of the pair of upper and lower molds includes a plurality of protrusions which protrude radially inward on an inner circumferential surface that defines the cavity portion, while extending in an axial direction,
• in step a), the plurality of protrusions contact each radially outer side surface of the plurality of magnets or radially face the radially outer side surface of the plurality of magnets across a slight gap, and
• in step c), a groove portion is formed in the resin portion by the plurality of protrusions.