Double crystal oscillator of ultrasonic transducer

The ultrasonic distance measuring transducer with double crystal oscillator is a bimorph ceramic that is bonded together and has opposite polarization directions.The working principle of the sheet is to apply an alternating electric field of opposite polarity to the upper and lower ceramic sheets in the double crystal oscillator, so that one of the piezo ceramic elements is elongated and the other ceramic element is shortened, so that the double crystal oscillator is a bending deformation vibration is generated to transmit a mechanical wave outward. A typical structure of a crystal bending vibration transducer, wherein the double crystal oscillator is square, and its left and right sides are supported by accurate convex portions, and the fulcrum is a vibration node of the vibrator. In order to improve the electromechanical conversion efficiency of the ultrasonic transducer for distance measurement, the double crystal oscillator with the metal plate and the conical vibrating body are fixed one by one, the cone is vibrating body metal plate.

  The piezoelectric component of the dual crystal oscillator is a twin crystal bending vibration transducer. When the ultrasonic wave is transmitted, since the cone-shaped vibrating body has a large radiating surface, the emitted sound wave has a strong directivity; when it is receiving the ultrasonic wave, the vibration energy of the acoustic wave is concentrated on the center of the vibrating body, so that the piezoelectric ultrasonic transducer vibrator can produces a large alternating charge.

Compared to other distance measuring transducer, the double crystal oscillator can transmit ultrasonic waves of larger amplitude under the excitation of the ultrasonic signal of the same amplitude. However, due to its own structural limitations, the thrust or vibration energy that such a transducer can provide is extremely limited, and it is not suitable for use in a field where the environmental pressure varies greatly. The radial vibration transducer is a structural schematic diagram of a radial vibration type ultrasonic probe made of a piezoelectric ceramic tube, and its radiation surface is perpendicular to the radial vibration direction of the circular tube. When the fundamental vibration of the radial vibration is 21 kHz, the outer diameter of the piezoelectric ceramic tube is about 100 mm, the working distance of ultrasonic range sensor is 25 m, and the dead zone is less than 0. 85 m.