Ultrasonic motor

An ultrasonic motor comprising:

• piezoelectric resonators for generating vibration waves;
• an elastic vibration member along which an elastic wave propagates when said piezoelectric resonators are driven;
• a sliding member located in contact with said elastic vibration member under pressure and adapted to slide along said elastic vibration member when the elastic wave propagates;
• and
• a friction member located on said sliding member and brought into frictional contact with said elastic vibration member, said friction member being made of a resinous material to which is added an additive selected from the group consisting of an inorganic powder and a fibrous material and having a hardness within the range of 40 to 120 measured by a Rockwell's R type hardness tester.

An ultrasonic motor comprising:

• piezoelectric resonators for generating vibration waves;
• an elastic vibration member along which an elastic wave propagates when said piezoelectric resonators are driven;
• a sliding member located in contact with said elastic vibration member under pressure and adapted to slide along said elastic vibration member when the elastic wave propagates;
• and
• a friction member located on said sliding member and brought into frictional contact with said elastic vibration member, said friction member being made of a resinous material to which is added an additive selected from the group consisting of an inorganic powder and a fibrous material and having a hardness within the range of 20 to 80 measured by a Rockwell's M type hardness tester.

An ultrasonic motor comprising:

• piezoelectric resonators for generating vibration waves;
• an elastic vibration member along which an elastic wave propagates when said piezoelectric resonators are driven;
• a sliding member located in contact with said elastic vibration member under pressure and adapted to slide along said elastic vibration member when the elastic wave propagates;
• and
• a friction member located on said sliding member and brought into frictional contact with said elastic vibration member, said friction member being made of a resinous material to which is added an additive selected from the group consisting of an inorganic powder and a fibrous material and having a hardness within the range of 40 to 90 measured by a Shore A type hardness tester, or the range of 20 to 70 measured by a Shore D type hardness tester.