Abstract An ultrasonic motor adapted to generate a travelling wave by a piezoelectric element and a vibrator to which the piezoelectric element is bonded, the displacement of these parts due to the travelling wave being amplified by a comb-like projection of the vibrator, arranged alternately in the circumferential direction thereof, to frictionally drive a movable member engaged under pressure with the vibrator characterized in that the piezoelectric element is provided on one surface thereof with fan-shaped electrode patterns, the number of which is a multiple of 4, arranged at regular intervals in the circumferential direction thereof, wherein the number of the fan-shaped electrode patterns and that of the vibrator have no common divisor with respect to each other, whereby the scatter of performance of ultrasonic motors, which is caused by a difference in the position in which the piezoelectric element and vibrator are bonded together, is eliminated to enable ultrasonic motors of uniform performance to be obtained.
An ultrasonic motor utilizing travelling wave generated in a vibrator for rotating a movable member comprising: a vibrator provided on one surface thereof with a piezoelectric element; comb-like projections arranged alternately in the circumferential direction thereof on the other surface of said vibrator; a movable member provided on said vibrator; a pressure-regulator provided on said movable member for generating suitable contact pressure between said movable member and said vibrator; and fan-shaped electrode patterns provided on one surface of said piezoelectric element, the number of which is a multiple of 4, arranged at regular intervals in the circumferential direction thereof, wherein the number of said fan-shaped electrode patterns and that of said comb-like projections of said vibrator have no common divisor with respect to each other.
Claim 2
Dependent Claim
125 words
An ultrasonic motor utilizing travelling wave generated in a vibrator for rotating a movable member comprising: a vibrator provided on one surface thereof with a piezoelectric element; comb-like projections arranged alternately in the circumferential direction thereof on the other surface of said vibrator; a movable member provided on said vibrator; a pressure-regulator provided on said movable member for generating suitable contact pressure between said movable member and said vibrator; and fan-shaped electrode patterns provided on one surface of said piezoelectric element, the number of which is a multiple of 4, arranged at regular intervals in the circumferential direction thereof, wherein the number of said fan-shaped electrode patterns and that of said comb-like projections of said vibrator have no common divisor with respect to each other.
Claim 3
Dependent Claim
17 words
An ultrasonic motor as claimed in claim 1 wherein said number of said fan-shaped electrode is 12.
Claim 4
Dependent Claim
17 words
An ultrasonic motor as claimed in claim 2 wherein said number of said comb-like projections is 25.
Claim 5
Dependent Claim
32 words
An ultrasonic motor as claimed in claim 1 wherein the center line of said one electrode pattern bonded to said piezoelectric element and the center line of said comb-like projections are aligned.