Method for assembling ultrasonic motor

A method for assembling an ultrasonic motor, the method comprising:

• providing a stator having a piezoelectric element;
• arranging a rotor to face the stator, wherein the piezoelectric element vibrates the stator to rotate the rotor;
• locating a lining member between the stator and the rotor, wherein the lining member has a predetermined thickness in the axial direction of the motor;
• installing an elastic member for pressing the rotor toward the stator, wherein normal wear of the lining member changes the deformation of the elastic member in the axial direction of the motor, and wherein the force of the elastic member pressing the rotor changes in accordance with the axial deformation of the elastic member;
• and
• pre-loading the elastic member, during assembly such that its deformation in the axial direction of the motor is in a predetermined deformation range, wherein the variation of the pressing force is relatively small for any deformation amount within the predetermined deformation range;
• and
• setting the initial axial deformation of the elastic member with an adjuster during assembly, wherein the step of setting the initial axial deformation of the elastic member with an adjuster comprises selecting a washer from washers having various thicknesses, wherein the selected washer is the adjuster.

A method for assembling an ultrasonic motor, the method comprising:

• providing a stator having a piezoelectric element;
• arranging a rotor to face the stator, wherein the piezoelectric element vibrates the stator to rotate the rotor;
• locating a lining member between the stator and the rotor, wherein the lining member has a predetermined thickness in the axial direction of the motor;
• installing an elastic member for pressing the rotor toward the stator, wherein normal wear of the lining member changes the deformation of the elastic member in the axial direction of the motor, and wherein the force of the elastic member pressing the rotor changes in accordance with the axial deformation of the elastic member;
• and
• pre-loading the elastic member, during assembly such that its deformation in the axial direction of the motor is in a predetermined deformation range, wherein the variation of the pressing force is relatively small for any deformation amount within the predetermined deformation range;
• coupling a rotary shaft to the rotor to integrally rotate with the rotor;
• supporting a supporting member on the rotary shaft such that the supporting member is prevented from moving axially away from the rotor;
• locating the elastic member between the supporting member and the rotor;
• and
• attaching a restrictor to the rotary shaft such that the restrictor engages the supporting member to prevent the supporting member from moving axially away from the rotor.