Patent ID: 7705518

Claim:
An ultrasonic motor, comprising: a stator that includes a comb body with a plurality of circumferentially-arranged comb-like projections and a piezoelectric body integrally mounted on the comb body; a rotor rotatable with respect to the stator, the rotor having a contact surface that establishes pressure contact with the stator; and a resin film formed with predetermined hardness on the contact surface of the rotor, the resin film containing a solid lubricant, wherein the resin film comprises one of: a resin film comprising a phenol epoxy resin, and a polytetrafluroethylene (PTFE) or fluorinated ethylene-propylene (FEP) solid lubricant, and having a pencil hardness of “B”; a resin film comprising a polyamide-imide resin, and a PTFE or graphite solid lubricant, and having a pencil hardness of at least “F”; and a resin film comprising a polyamide-imide resin and a PTFE or molybdenum disulfide (MoS 2 ) solid lubricant, and having a pencil hardness of at least “F”.