Permanent magnet and method of manufacturing motor
A permanent magnet includes a magnet member, and an adhesive layer covering a surface of the magnet member, wherein the adhesive layer includes a resin and a plurality of foaming agents, and wherein at least part of the foaming agents protrudes from a surface of the resin.
1. A permanent magnet comprising:
a magnet member; and
an adhesive layer covering a surface of the magnet member,
wherein the adhesive layer includes a resin and a plurality of foaming agents, and
wherein at least part of the foaming agents protrudes from a surface of the resin.
2. The permanent magnet according to claim 1 ,
wherein at least part of the resin is a semi-cured material.
3. The permanent magnet according to claim 1 ,
wherein at least part of the resin is a thermosetting resin.
4. The permanent magnet according to claim 1 ,
wherein φ is a width of at least part of the foaming agents in a direction perpendicular to the surface of the magnet member, and
wherein T is a thickness of the resin in a direction perpendicular to the surface of the magnet member, and
T is 0.5φ or more and less than φ.
5. A method of manufacturing a motor, the method comprising:
a preparation step of obtaining a mixture containing a thermosetting resin and a plurality of foaming agents;
a printing step of applying the mixture to a surface of a magnet member to form an adhesive layer on the surface of the magnet member;
a first heating step of, by heating the adhesive layer, semi-curing the thermosetting resin contained in the adhesive layer to obtain a permanent magnet;
a housing step of inserting, after the first heating step, the permanent magnet into a housing hole formed in a rotor core; and
a second heating step of, by heating the adhesive layer after the housing step, foaming the foaming agent contained in the adhesive layer and further curing the thermosetting resin contained in the adhesive layer,
wherein φ is a width of at least part of the foaming agents in a direction perpendicular to the surface of the magnet member,
wherein T is a thickness of the resin in the direction perpendicular to the surface of the magnet member, and
wherein in the printing step, T/φ is adjusted to a value greater than 0 and less than 1.
6. The method of manufacturing a motor according to claim 5 ,
wherein the mixture is applied to the surface of the magnet member by screen printing in the printing step.