Fundamental study on micro ultrasonic motor

为了使超声电机的主要尺寸减小到mm级，压电材料和摩擦驱动条件是最重要的因素。我们尝试改进水热法在钛基材料上沉积PZT薄膜。然后，研究了纳米级超声振动的虚拟驱动条件，得到了有趣的结果。改进后的在钛上沉积PZT薄膜的方法是一个单一的过程。考察了反应温度、溶液中物料密度和KOH浓度对反应的影响。因此，该反应过程单一，易于控制。PZT薄膜成功地沉积在钛目录上。改进后的压电薄膜在制造微型超声电机方面具有优越的性能。在5V驱动电压下，输出转矩为7munm。它比上一个大40倍。采用10 MHz表面声波直线电机对摩擦驱动条件进行了研究。在获得较大输出力的最佳条件下，力密度大于100 N/nm^2。6mm × 6mm滑块的实际输出力约为0.45 N。采用更高的驱动频率、更高的接触压力和改进的PZT薄膜，可以实现亚毫米级的微型超声电机。

For reduction of the size of ultrasonic motor down to mm order in its major size, piezoelectric material and the friction drive condition are the most important factor. We tried to improve the hydro thermal method to deposit the PZT thin film on titanium base material. Then, the fiction drive condition of nm order ultrasonic vibration has been investigated and obtained interesting results.The improved way of depositing the PZT film on titanium is a single process. The process temperature, density of material in the solution and the KOH density were examined to optimize the reaction. Hence the process is single, the control of the reaction was rather easy. The PZT film was successfully deposited on titanium directory. The improve piezoelectric film has superior performance to make micro ultrasonic motor. At 5V driving voltage, the output torque was 7 muNm. It was 40 times lager than previous one.The friction drive condition was investigated using 10 MHz surface acoustic wave linear motor. At the optimum condition to obtain larger output force, the force density was more than 100 N/nm^2. The actual output force was about 0.45 N by 6mm x 6mm slider.By using higher driving frequency, high contact pressure and improved PZT thin film, micro ultrasonic motor down to sub mm size will be available.