Analyses of the temperature field of traveling-wave rotary ultrasonic motors

In this paper the contact mechanism between stator and rotor will be considered in detail, which plays a key role in ultrasonic motors. A planar contact model for the stator-rotor interaction in traveling-wave type ultrasonic motors is derived, including rotor flexibility and differenciating between stick and slip regions in the contact zones. The model analysis shows that depending on the motor’s operating conditions, complicated contact behavior may occur with several stick-slip subzones in each contact zone. The typical nonlinear resonance observed in ultrasonic motors can be explained with the present analysis. Both the stiffness of the contact layer and of the rotor may drastically influence the speed-torque characteristics. The results will contribute to a better understanding of the contact mechanics in ultrasonic motors.

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Effects of Ultrasonic Motor Stator Teeth Height on Start Reliability

Energy Harvesting and Systems ◽

10.1515/ehs-2014-0028 ◽

2015 ◽

Vol 0 (0) ◽

Cited By ~ 1

Author(s):

Wei Zheng ◽

Jing-Liang Zhou ◽

Yu-Zhen Ruan

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Traveling Wave ◽

Ultrasonic Motor ◽

Wave Type ◽

Element Analysis ◽

Factors Affecting ◽

Ultrasonic Motors ◽

Wide Range ◽

New Type

AbstractAs a new type of motor, the traveling wave type rotary ultrasonic motors (TRUM) have a wide range of applications. However, the friction between stator and rotor leads to its poor start reliability, which retards the progress of application of ultrasonic motors. Sometimes TRUMs which are widely used cannot start after storage. Height of tooth of the ultrasonic motor’s stator is one of the factors affecting TRUM’s start stabilizing. In this paper, combined with the ultrasonic motor running mechanism, the factors that affect TRUM’s start reliability are studied. Model of ultrasonic motor stator tooth height is analyzed by finite element analysis (FEA). Five TRUMs with different tooth heights are fabricated and measured. A TRUM with 1.85 mm tooth height can start properly in humidity 90%, but ultrasonic motors with 1.8–1.9 mm tooth height cannot start properly under the same conditions.

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Contact Modeling of Traveling Wave Ultrasonic Motors

2014 Conference on Information Storage and Processing Systems ◽

10.1115/isps2014-6985 ◽

2014 ◽

Author(s):

Shengnan Shen ◽

Hui Li ◽

Fuhao Cui ◽

Guoqing Zhang ◽

Xiangyu Dai

Keyword(s):

Traveling Wave ◽

Three Dimensional ◽

Disk Drive ◽

Element Model ◽

Friction Material ◽

Contact Friction ◽

Ultrasonic Motors ◽

Head Positioning ◽

Cohesive Zone Elements ◽

Three Dimensional Finite Element

In the pursuit of high areal recording density towards 10 Tb/in2, it is necessary to improve the positioning accuracy of the magnetic head in the hard disk drive head-positioning control system. Ultrasonic motors (USMs) are novel electric motors used for positioning controls. Due to the drive characteristic of USMs, wear and fatigue of friction material at the contact friction interface are inevitable. Contact deformation can cause local damage of USMs. Therefore, obtaining the details of the stress distribution in the friction material due to the inelastic deformation is important. In this work, a contact model of traveling wave ultrasonic motor (TWUSM) is proposed. A three dimensional finite element model with cohesive zone elements embedded between friction material and rotor is then developed. Infinite finite elements are incorporated in this modeling as the boundary condition as the model thickness is typically many orders smaller than the longitudinal dimension. The evolution of deformation in friction material and rotor due to the mechanical surface loading is presented. The possible interfacial delamination process between friction material and rotor is numerically studied. And the friction coefficient effect of the friction material on the delamination propagation is also investigated.

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