Rotor, motor, fan, air conditioner, and manufacturing method of rotor

A rotor comprising:

• a shaft made of a resin;
• an annular rotor core surrounding the shaft from an outer side in a radial direction about a center axis of the shaft;
• a magnet attached to the rotor core;
• and
• a separating portion provided between the shaft and the rotor core and having electric insulation property,
• wherein the magnet constitutes a first magnetic pole, and a part of the rotor core constitutes a second magnetic pole,
• wherein the rotor core has an inner circumference facing the shaft and an outer circumference opposite to the inner circumference, and
• wherein a radius R1 of the shaft and a maximum distance R2 from the center axis to the outer circumference of the rotor core satisfy:
• R1/R2≥0.49.

A rotor comprising:

• a shaft made of a ceramics;
• an annular rotor core surrounding the shaft from an outer side in a radial direction about a center axis of the shaft;
• a magnet attached to the rotor core;
• and
• a separating portion provided between the shaft and the rotor core and having electric insulation property,
• wherein the magnet constitutes a first magnetic pole, and a part of the rotor core constitutes a second magnetic pole,
• wherein the rotor core has an inner circumference facing the shaft and an outer circumference opposite to the inner circumference, and
• wherein a radius R1 of the shaft and a maximum distance R2 from the center axis to the outer circumference of the rotor core satisfy:
• R1/R2≥0.40.

A manufacturing method of a rotor, the method comprising the steps of:

• preparing an annular rotor core to which a magnet constituting a first magnetic pole is attached and which has a part constituting a second magnetic pole, and a shaft made of a stainless steel, and
• forming a separating portion using an electrically insulating resin between the shaft and the rotor core by placing the shaft and the rotor core in a molding mold so that the rotor core surrounds the shaft, and
• wherein a radius R1 of the shaft and a maximum distance R2 from a center axis of the shaft to an outer circumference of the rotor core satisfy:
• R1/R2≥0.20.

A manufacturing method of a rotor, the method comprising the steps of:

• preparing an annular rotor core to which a magnet constituting a first magnetic pole is attached and which has a part constituting a second magnetic pole, and a shaft made of a resin;
• and
• forming a separating portion using an electrically insulating resin between the shaft and the rotor core by placing the shaft and the rotor core in a molding mold so that the rotor core surrounds the shaft,
• wherein a radius R1 of the shaft and a maximum distance R2 from a center axis of the shaft to an outer circumference of the rotor core satisfy:
• R1/R2≥0.49.

A manufacturing method of a rotor, the method comprising the steps of:

• preparing an annular rotor core to which a magnet constituting a first magnetic pole is attached and which has a part constituting a second magnetic pole, and a shaft made of a ceramics, and
• forming a separating portion using an electrically insulating resin between the shaft and the rotor core by placing the shaft and the rotor core in a molding mold so that the rotor core surrounds the shaft,
• wherein a radius R1 of the shaft and a maximum distance R2 from a center axis of the shaft to an outer circumference of the rotor core satisfy:
• R1/R2≥0.40.