Design of a Micro Linear Ultrasonic Motor with a Preload Mechanism

Shunsuke Izuhara, Tomoaki Mashimo

Research output: Contribution to journalArticlepeer-review


We present a micro linear piezoelectric ultrasonic motor, which can be used for zooming and autofocusing features in camera modules inside cellphones and endoscopes, it consists of a cuboid stator with a hole and an elastic cylindrical slider. The motor design, in which the slider inserted into the stator hole expands outward, enables a hollow structure for an optimal preload for enhancing the motor thrust force, (n this study, we model the relationship between the dimensions and the preload to quantify the preload value and clarify the design methodology. The size of the prototype stator with piezoelectric elements measures 2,6 mm in height and width and 2.2 mm in depth (the length in slider travel direction). There is a hole of 1,7 mm in diameter at the stator center, and the slider inserted into the hole operates when voltages are applied to the piezoelectric elements. Applying an optimized preload, we evaluate the fundamental characteristics of the motor in experiments, A thrust force of approximately 40 mN and a resolution of about 1 μm were obtained, which may satisfy the specification of a certain type of camera modules.

Original languageEnglish
Pages (from-to)51-56
Number of pages6
JournalSeimitsu Kogaku Kaishi/Journal of the Japan Society for Precision Engineering
Issue number1
Publication statusPublished - 2022


  • Ferroelectric
  • Microactuators
  • Piezoelectric actuators
  • Resonant mode
  • Ultrasonic motor

ASJC Scopus subject areas

  • Mechanical Engineering


Dive into the research topics of 'Design of a Micro Linear Ultrasonic Motor with a Preload Mechanism'. Together they form a unique fingerprint.

Cite this