Resolver

A resolver comprising:

• a rotor having an oval shape when viewed in an axial direction;
• and
• a stator arranged to surround an outer peripheral surface of the rotor,
• wherein the rotor includes a rotor core, the stator includes a stator core and a coil, the stator core includes a plurality of teeth disposed at intervals along a circumferential direction and a cutting protrusion that projects toward the outer peripheral surface side of the rotor, the plurality of teeth project toward the outer peripheral surface side of the rotor, and the coil is wound around the plurality of teeth,
• the resolver is configured so that a gap permeance between the rotor and the stator varies in association with a rotation around a rotation axis of the rotor, and
• the rotor further includes a porous machinable film containing a magnetic metal, and the porous machinable film is disposed on a projecting portion on an outer peripheral surface of the rotor core,
• wherein the porous machinable film is configured to be cut by the cutting protrusion based on the cutting protrusion being in contact with the porous machinable film when the rotor rotates.