A V-shaped small linear ultrasonic motor with multilayered piezoelectric stacks

For accomplishing of a linear ultrasonic motor with low driving voltage, small size and large output force, a novel V-shaped linear ultrasonic motor with multilayered piezoelectric stacks has been developed. Firstly, the piezoelectric ceramic used in the stack is fabricated. The piezoelectric ceramic has excellent multilayered co-firing characteristic with Ag electrode to form the multilayered piezoelectric stack. Secondly, the motor which consists of a stator, a slider and a fixed base is proposed. The stator of the motor is composed of a drive tip and two piezoelectric stacks. The stator has two resonance vibration modes, symmetrical and unsymmetrical. The elliptic track motion of the drive tip would be formed by exciting the symmetrical and unsymmetrical vibrations synchronously and the slider compressed on the stator can be driven via friction for moving linearly. The design of the stator make symmetrical and unsymmetrical mode frequencies become equal. In the condition of driving voltage 5 V, frequency 96.915 kHz and driving electric current 0.8 A, the no-load maximum speed is 25.78 mm/s, and the maximum output forces 2.14 N. The tests indicate the proposed motor accomplishes large output force with small size and low diving voltage.