Piezoelectric motor, liquid ejecting apparatus, and clock

Abstract

A piezoelectric motor includes a piezoelectric element having a piezoelectric layer, and a first and a second electrodes, the first electrode provided on one surface side of the piezoelectric layer, and the second electrode provided on the other surface side of the piezoelectric layer; a piezoelectric actuator having a vibrating member anchored to the first electrode of the piezoelectric element; and a rotational shaft with which the vibrating member makes contact and is rotated thereby. The piezoelectric layer includes a vertical vibration excitation region, provided toward the center of the piezoelectric layer in the widthwise direction, that elicits vertical vibrations, and two groups of bending vibration excitation regions, one group disposed on either side of the vertical vibration excitation region so that two opposing diagonal pairs are formed; and the polarization direction of the vertical vibration excitation region and one of the groups of the bending vibration excitation regions in the piezoelectric layer is inverted relative to the other group of the bending vibration excitation regions.

What is claimed is: 
     
         1 . A piezoelectric motor comprising:
 a piezoelectric element including a piezoelectric layer, and a first and a second electrodes, the first electrode formed one side of the piezoelectric layer, and the second electrode formed the other side of the piezoelectric layer;   a piezoelectric actuator including a vibrating member anchored to the first electrode of the piezoelectric element; and   a rotational shaft with which the vibrating member makes contact and is rotated thereby,   wherein the piezoelectric layer includes two groups of bending vibration excitation regions, one group disposed on either side of the vertical vibration excitation region so that two opposing diagonal pairs are formed; and   a polarization direction of one of the groups of the bending vibration excitation regions in the piezoelectric layer is inverted relative to the other group of the bending vibration excitation regions.   
     
     
         2 . The piezoelectric motor according to  claim 1 , wherein the second electrode includes a bending vibration electrode portion linking the two groups of bending vibration excitation regions, and a vertical vibration electrode portion provided on the vertical vibration excitation region. 
     
     
         3 . The piezoelectric motor according to  claim 2 , wherein the bending vibration electrode portion is linked at its ends in the lengthwise direction of the piezoelectric element. 
     
     
         4 . The piezoelectric motor according to  claim 1 , wherein the first electrode includes a first polarization electrode portion and a second polarization electrode portion divided into regions of the piezoelectric layer of which polarization directions are different to each other, and provided so as to be electrically conductive with those regions. 
     
     
         5 . A liquid ejecting apparatus comprising the piezoelectric motor according to  claim 1 . 
     
     
         6 . The liquid ejecting apparatus according to  claim 5 , wherein the piezoelectric motor is used as a paper supply unit for transporting an ejection target medium onto which a liquid is ejected. 
     
     
         7 . A clock comprising the piezoelectric motor according to  claim 1 .