东莞思威特电子压电陶瓷的典型应用.docVIP

东莞思威特电子压电陶瓷的典型应用 一、压电声响器Piezoelectric ceramic sounder 发声元件的结构he structure sounding element 罗宾逊和迪得逊对健康人的耳朵进行测验的结果，发现耳朵对3千赫左右的频率最为敏感。因此，压电陶瓷发声元件的谐振频率设计在3000Hz左右。 一般采用如图2.25所示结构，其外形尺寸为直径10-50毫米，总厚度0.4-0.5毫米.在压电陶瓷发生元件上施加交变电压时,发声元件挠曲振动，振动基波的谐振频率可由下式给出: Robinson and D tested the healthy human`s ears, they had found that the most sensitive frequency is 3KHz to human`s ear. So, the resonant frequency of piezoelectric ceramic sounder is 3KHz in design. Generally, using the structure as shown in Fig.2.25, the diameter size is in 10-50 mm, the total thickness is in 0.4-0.5 mm. The sounder element will produce flexural vibration when the piezoelectric ceramic element input AC voltage. The resonant frequency of fundamental vibration wave is shown the formula. C-振动片固定方式常数(波节固定时为0.467,周边固定时为0.233); t-厚度; r-半径; Y0-杨氏模量; ρ0-金属振动片和压电陶瓷片的合成密度。 因此，当材料一定时，压电陶瓷发声元件的频率与其总厚度成正比，与其半径平方成反比。如图2.26所示.C-The fixed mode constant of vibrator(Wave node fixed mode equal to 0.467, Circum node fixed mode equal to 0.233); t- thickness; r- radii; Y0-Young modulus; ρ0- Metal disk and piezoelectric ceramic disk of combining density So, the frequency of piezoelectric ceramic sounder and the total thickness are direct proportion, and the quadratic radius is inversely proportion when the material is given. As shown in Fig.2.26. 压电陶瓷发声元件的谐振频率随复合振动片直径的增加成指数曲线下降。 发声元件中的压电陶瓷片的大小主要根据对阻抗的要求确定。图2.28是压电陶瓷片的直径d与金属振动片的直径D的比值与谐振阻抗的关系。The resonant frequency of piezoelectric sounder and the diameter compound vibration plate decreases with the exponential curve. The piezoelectric ceramic size of sounder is confirmed which is based on the required impedance. The ration of piezoelectric ceramic diameter d and metal diameter D, it and the resonant impedance relation is shown in the Fig.2.28. 由图可知，对于基波振动来说，d/D的比值越趋近于1，谐振电阻越小，即要获得较低的阻抗值必须使压电陶瓷片的直径接近于金属振动片的直径，其比值小于0.7。 It can be seen from the figure, for fundamental wave vibration, d / D ratio is approach 1, the resonance resistance is getting smaller, the piezo