Ultrasonic transducer is widely used in industry, agriculture, transportation, life, medical and military fields. According to the functions, it can be divided into ultrasonic machining, ultrasonic cleaning, ultrasonic detection, detection, monitoring, telemetry, remote control, etc; According to the working environment, it can be divided into liquid, gas, organism, etc; According to the nature, it can be divided into power ultrasound, detection ultrasound, ultrasonic imaging, etc.

Piezoelectric ceramic transformer

Piezoelectric ceramic transformer uses the piezoelectric effect of polarized piezoelectric body to realize voltage output. The input part is driven by sinusoidal voltage signal and vibrates through the inverse piezoelectric effect. The vibration wave is mechanically coupled to the output part through the input and output parts. The output part generates electric charge through the positive piezoelectric effect, which realizes the two-step transformation of electric energy mechanical energy electric energy of the piezoelectric body and obtains the highest output voltage at the resonant frequency of the piezoelectric transformer. Compared with the electromagnetic transformer, it has the advantages of small volume, light weight, high power density, high efficiency, breakdown resistance, high temperature resistance, no fear of combustion, no electromagnetic interference and noise, simple structure, easy to manufacture, easy to mass production, and become an ideal alternative component of electromagnetic transformer in some fields. This kind of transformer is used in switch converter, notebook computer, neon lamp driver, etc.

Ultrasonic motor

Ultrasonic motor uses stator as transducer, and makes use of the piezoelectric effect of piezoelectric crystal to make the stator vibrate at ultrasonic frequency. Then, the friction between stator and rotor is used to transmit energy and drive the rotor to rotate. The advantages of ultrasonic motor are small volume, large torque, high resolution, simple structure, direct drive, no brake mechanism and bearing mechanism, which are beneficial to the miniaturization of the device. Ultrasonic motor is widely used in optical instruments, laser, semiconductor microelectronics, precision machinery and instruments, robots, medicine and bioengineering fields.

ultrasonic cleaning

The mechanism of ultrasonic cleaning is to use the cavitation, radiation pressure, sound flow and other physical effects when ultrasonic wave propagates in the cleaning solution to peel off the dirt on the cleaning parts. At the same time, it can promote the chemical reaction between the cleaning solution and the dirt, so as to achieve the purpose of cleaning objects. According to the size and purpose of the cleaning material, the frequency of ultrasonic cleaning machine can be 10-500 kHz, generally 20-50 kHz. As the frequency of ultrasonic transducer increases, Langevin vibrator, longitudinal vibrator and thickness vibrator can be used. In the aspect of miniaturization, radial vibration and bending vibration of disk vibrator are also used. Ultrasonic cleaning is widely used in various industries, such as industry, agriculture, household equipment, electronics, automobile, rubber, printing, aircraft, food, hospital and medical research.

Ultrasonic welding

Ultrasonic welding includes ultrasonic metal welding and ultrasonic plastic welding. Among them, ultrasonic plastic welding technology has been widely used. It uses the ultrasonic vibration generated by the transducer to transmit the ultrasonic vibration energy to the welding area through the upper weldment. Due to the large sound resistance at the junction of the two weldments, local high temperature will be generated to melt the plastic, and the welding work will be completed under the action of contact pressure. Ultrasonic plastic welding can be used to weld parts that cannot be welded by other welding methods. In addition, it also saves the expensive mold cost of plastic products, shortens the processing time, improves the production efficiency, and has the characteristics of economy, speed and reliability.

Ultrasonic machining

When the micro abrasive is added to the workpiece with a certain static pressure together with the ultrasonic machining tool, the same shape as the tool can be machined. The transducer needs to produce 15-40 μ m amplitude at the frequency of 15-40 kHz. Ultrasonic tools make the abrasive on the surface of the workpiece impact continuously with a considerable impact force, destroy the ultrasonic radiation parts, break the material and achieve the purpose of removing the material. Ultrasonic machining is mainly used in the processing of brittle and hard materials such as gems, jade, marble, agate, cemented carbide, and the processing of special-shaped holes and fine deep holes. In addition, when the ultrasonic transducer is added to the common cutting tool, the accuracy and efficiency can be improved.

Ultrasonic weight loss

By using the cavitation effect and micro mechanical vibration of ultrasonic transducer, the extra fat cells under the human epidermis are broken and emulsified and discharged out of the body to achieve the purpose of weight loss and shaping. This is a new technology developed in the 1990s. Zocchi of Italy first used ultrasound to remove fat in bed, and achieved success, creating a precedent for plastic surgery and beauty. Ultrasonic degreasing technology has developed rapidly at home and abroad.

Ultrasonic breeding

Ultrasonic irradiation with appropriate frequency and intensity can improve the germination rate of seeds, reduce the mildew rate, promote the growth of seeds and improve the growth rate of plants. According to the data, ultrasonic can increase the growth rate of some plant seeds by 2-3 times.

Electronic sphygmomanometer

The ultrasonic transducer is used to receive the pressure of the blood vessel. When the balloon compresses the blood vessel, the ultrasonic transducer can not feel the pressure of the blood vessel because the applied pressure is higher than the diastolic pressure of the blood vessel; When the balloon gradually deflates and the pressure of the ultrasonic transducer on the blood vessel decreases to a certain value, the pressure of the two is balanced. At this time, the ultrasonic transducer can feel the pressure of the blood vessel, which is the systolic pressure of the heart, and send out the indication signal through the amplifier to give the blood pressure value. Because of the elimination of stethoscope, the electronic sphygmomanometer can reduce the labor intensity of medical staff.

Telemetry and Telecontrol

In the toxic, radioactive and other harsh environment, people can not get close to work, need to control far away; TV sets, electric fans, lamps and other electrical switches need remote control, can be installed with ultrasonic transducers, through the remote emission of ultrasonic, received by the receiving transducer installed on the control system, the acoustic signal into electrical signal to make the switch action.

Traffic monitoring

In modern transportation, it is very necessary to monitor the passing and counting of vehicles automatically in order to master the operation of vehicles. If the traffic supervision station is equipped with an ultrasonic transducer and its auxiliary equipment, when the vehicle passes, an acoustic pulse will return, and the number of daily vehicles can be obtained by counting. A transducer for transmitting and receiving can be installed at the rear of the car to prevent the accident of reversing collision. The noise figure can also be monitored by installing the receiving piezoelectric ultrasonic transducer on the highway.

ranging

Ultrasonic distance measuring device is also called ruler. It is a transducer which can be used to measure the pulse time interval. The sound ruler can measure the distance within 10m, and the accuracy can reach several thousandths.

Leak detection and gas detection

For the pressure system, the jet noise is caused by the pressure difference between the inside and outside of the pressure vessel at the leakage point. The noise spectrum is very wide. For non pressure systems, an ultrasonic wave source can be placed in the closed system and then received from the outside of the closed system. Generally, when there is no leakage, the signal amplitude is very small or not, and the signal amplitude increases suddenly at the leakage point. Gas flow detection is also one of the important means in chemical industry. At present, there are many kinds of amplification for flow detection, such as rotameter. But the main advantage of using ultrasonic transducer is that it does not hinder the flow of fluid.

information acquisition

In order to realize the functions of walking freely and identifying objects in space, the intelligent robot not only uses ultrasonic transducer to guide the blind, but also needs imaging identification. Therefore, we need a small ultrasonic transducer array to achieve a variety of functions, which will become an important research topic and attract many scientists.