High-reliability high-stability-degree hollow rotating traveling wave ultrasonic motor

Abstract

The invention relates to a high-reliability high-stability-degree hollow rotating traveling wave ultrasonic motor, which belongs to the technical field of the small and special motor. The ultrasonic motor comprises an encloser, a rotor, friction material, a stator, piezoelectric ceramic, a stator seat, a bearing, a dust cover for the bearing, and a loading nut. The motor disclosed by the invention is supported by one bearing, an anti-redundancy structure is designed, and the motor rotor and the stator seat are made of stainless steel material with the coefficient of linear expansion similar to that of the bearing. The situations that the revolving speed fluctuation quantity of the ultrasonic motor is raised, and the moment output performance is lowered, and the service life of the ultrasonic motor is shortened due to a plurality of factors can be effectively improved, wherein the factors comprise that the pressure distribution of the contact interface of the stator and the rotor is uneven due to double-end bearing supporting, more mutually-cooperated sizes and big deviation of machining and assembling of the ultrasonic motor; abrasive dust generated by motor working enters the bearing; the coefficients of linear expansion of materials are in a great difference under the high temperature and low temperature working conditions; and a fit clearance is changed.

Description

technical field [0001] The invention relates to a high-reliability and high-stability hollow rotary traveling-wave ultrasonic motor, in particular to an ultrasonic motor with high reliability, high rotational speed stability and hollow structure requirements, belonging to the technical field of micro-special motors. Background technique [0002] Ultrasonic Motor (Ultrasonic Motor) is a new concept power device developed in the past two decades. Its essence is to rely on the inverse piezoelectric effect of piezoelectric ceramics to convert electrical energy into mechanical energy of the elastic body, so that the stator generates high-frequency micro-vibration (micron level), and then utilizes the contact and friction between the stator and the rotor to move the stator The slight vibration of the rotor is converted into the rotary or linear motion of the rotor, so as to output mechanical energy to drive the load to work. This new type of motor is driven by an AC power source ...

AI Technical Summary

Problems solved by technology

Because it is supported by double-ended bearings, there are many sizes that cooperate with each other, and the large deviations in machining and assembly cause the rotor axis to be deflected relative to the stator axis, and the pressure distribution on the contact interface between the stator and the rotor is uneven, which in turn leads to fluctuations in the speed of the ultrasonic motor. rise, torque output performance decline, and life shortening; the current rotary traveling wave ultrasonic motor rotor and stator seat are generally made of aluminum alloy material, and the bearing material matched with it is bearing steel, due to the linear expansion coefficient of aluminum alloy (23.3E- 6 / K) is quite different from the linear expansion coefficient of bearing steel (9.92E-6 / K). In different high and low temperature conditions, the inconsistency in the size change of the parts caused by the mismatch of the linear expansion coefficient of the material causes the rotor axis relative to the stator The axis is deflected, and the pressure distribution of the contact interface between the stator and the rotor is uneven, which leads to an increase in the speed fluctuation of the ultrasonic motor and a decrease in the torque output performance; the axial dimension of the shaft-out double-ended bearing support structure is large, which is not conducive to the realization of Due to the miniaturization and light weight requirements of ultrasonic motors, ultrasonic motors with output shaft structure cannot be used in the field of aerospace where the commonly used motors are used with slip rings and where the core of the motor needs to be routed; Because there is no protection, the external excess will enter the support bearing, which will cause the friction torque of the bearing to fluctuate or even stall, making the ultrasonic motor speed fluctuation increase or even stop, the life of the ultrasonic motor is short and the reliability is low; the stator and rotor of the ultrasonic motor The wear debris generated during operation will overflow through the gap between the rotor and the outer cover, causing pollution to the outside world, especially in the microgravity environment of space, the abrasive debris overflowing may contaminate important payloads such as cameras, causing partial function loss or even failure of the spacecraft

Images