US 5,027,028 A · Piezoelectric motor

Abstract

A piezoelectric motor having a cylindrical outer motor casing formed by a separable two part housing that encloses and supports 3 piezoelectric actuators and a group of rotatable components. The rotatable components include a rotating output shaft that extends from the housing for coupling a load thereto, three drive rollers that engage the output shaft and are evenly spaced thereabout, and an idler ring assembly that secures the drive rollers about the output shaft when the motor is assembled. The housing has six piezoelectric stacks mounted in a fixed position to interior surfaces of the housing. Each stack is cylindrical with one flat end attached to the housing and the other flat end having a truncated cone shaped crown roller mounted thereon. The stacks are positioned so that when the two housing parts are assembled the piezoelectric stacks are aligned in pairs with their crown rollers adjacent each other to provide three piezoelectric actuators evenly spaced at 120 degree intervals about the center line of the motor. The three piezoelectric actuators support and position the rotatable components within the assembled housing during motor operation. When electrically energized by at least a pair of out of phase sinusoidal voltages the stacks deform along two perpendicular axes so that the crown rollers nutate in a substantially circular motion while bearing against internal surfaces of the three drive rollers to cause rotation of the drive rollers. External surfaces of the drive rollers engage the output shaft to cause it to rotate. Power amplifiers that provide the voltage drive required by high capacitive devices such as this motor are disclosed in U.S. Pat. No. 4,628,275 referenced in this patent application.

Claims7

Dependent claims

A piezoelectric motor for providing a powerful and compact source of variable speed rotary motion that can be coupled to a load, said motor comprising:

separable housing means that forms the outer casing of said motor;
rotatable means mounted in said housing means for rotation therein and including an output shaft means that extends from said housing so that the rotary motion of said rotatable means can be coupled to a load, and drive roller means positioned adjacent said output shaft means for engaging and rotating said output shaft means;
at least three nutating piezoelectric actuator means attached to the interior walls of said housing means and positioned adjacent said drive roller means, said piezoelectric actuator means deforming in both directions along two perpendicular axes when a voltage is applied thereto to engage and rotate said drive roller means and impart rotary motion to said output shaft means;
electrical conducting means mounted in said motor and connected to said piezoelectric actuator means, and
electrical drive means connected to said electrical conducting means for providing a suitable voltage to said motor.

2 more elements

Dependencies are inferred from the claim text.

Piezoelectric motor

Life of this patent

Piezoelectric motor

Life of this patent

Abstract

Claims7