The working principle of a sonic toothbrush is: The high-speed movement of a micro motor drives the head of the toothbrush to swing at high speed, producing mechanical vibration, that is, producing sound waves. The suitable vibration frequency of the sonic toothbrush is between 166-666Hz(10000-37000 times/min). Different frequencies of sonic toothbrushes can achieve different degrees of tooth-cleaning effects. The cleaning effect of a sonic toothbrush is proportional to the frequency and amplitude of sound waves.

2. Acoustic wave generation principle

 (1) High-speed micro motor eccentric vibration principle: This principle is more common, but also widely used. Usually, the motor speed up to 30,000 RPM is appropriate, higher speed will affect the life of the motor itself. The amplitude and noise generated by acoustic vibration vary with different specifications of motors and structural designs of toothbrushes, and there is no absolute statement.

(2) Magnetic levitation motor high-frequency vibration principle: Electromagnetic plus vibration device as a vibration source, the principle: After electrifying electromagnetic device to form a magnetic field, vibration device suspended in the middle of the magnetic field, the formation of high-frequency vibration frequency, and then through the transmission shaft conduction to the toothbrush.

This vibration principle does not produce mechanical friction inside the motor, strong stability, the output power is relatively large, produce sound frequency up to 37,000 times per minute. The higher the frequency of the sound wave, the higher the relative technical difficulty of the motor.