Piezoelectric tuning mechanism

Abstract

The invention discloses a piezoelectric tuning mechanism which is characterized in that the piezoelectric tuning mechanism comprises a piezoelectric ceramic and a displacement amplifier, the displacement amplifier being roughly in a structure shown in the figure in the specification. The displacement amplifier comprises elastic portions and support portions. The portions, made of elastic alloy materials, of the four edges of the displacement amplifier form the elastic portions of the displacement amplifier; and the portions, made of low-expansion alloy materials, of the four edges, except the elastic portions, of the displacement amplifier form the support portions of the displacement amplifier, the expansion coefficient of the elastic alloy being larger than that of the piezoelectric ceramic. The piezoelectric ceramic is fixedly connected to the two edges of the displacement amplifier, and thus the piezoelectric tuning mechanism is roughly in the structure shown in the figure in the specification. The piezoelectric tuning mechanism is high in electromechanical energy conversion efficiency, small in power consumption, short in response time, good in maximum tuning frequency, good in material stability, and good in position repeatability; the positioning precision is allowed to be higher, and frequency / frequency locking precision of a magnetron is higher; the output thrust is large; and the displacement amount is large.

Description

technical field [0001] The invention relates to a tuning mechanism, in particular to a piezoelectric tuning mechanism. Background technique [0002] At present, the dither tuning methods of the magnetron are divided into: hydraulic tuning, mechanical dither tuning, voice coil dither tuning, and piezoelectric crystal dither tuning. These kinds of tuning methods all use different devices to generate back and forth motions, and drive the tuning disc of the magnetron to reciprocate in the cavity through the transmission mechanism, so as to achieve the purpose of frequency tuning. [0003] Hydraulic tuning is to achieve the purpose of magnetron tuning through the control of liquid pressure. This tuning method has a relatively simple theoretical structure and a long stroke, but the tuning speed is very low, and this tuning method must have a sealing device that can withstand high pressure liquid. Therefore, its reliability is relatively poor, and the equipment for providing hydra...

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Problems solved by technology

[0003] Hydraulic tuning is to achieve the purpose of magnetron tuning through the control of liquid pressure. This tuning method has a relatively simple theoretical structure and a long stroke, but the tuning speed is very low, and this tuning method must have a sealing device that can withstand high pressure liquid. Therefore, its reliability is poor, and the equipment that provides hydraulic pressure and its servo control system are very large

[0004] Mechanical vibration tuning is to change the rotational displacement of the motor into a back and forth displacement to push the tuning element through the transmission structure (usually through the crankshaft or universal head). This tuning method is affected by the crankshaft or universal head, and the required torque is large. Therefore, its tuning frequency cannot be too high, generally lower than 100Hz (that is, the motor speed does not exceed 6000 rpm), the motor is large in size, and the transmission structure also requires a large space

[0005] The only difference between voice coil trembling tuning and mechanical trembling tuning is that electromagnetic force is used instead of mechanical force to drive the tuning element. The disadvantage is that: the tuning frequency is still low, generally around 200Hz; the introduction of two bellows adds a leak source; the voice coil is in a radial magnetic field, and the magnetic steel of the magnetron itself has strong magnetic flux leakage, which is easy to interfere with each other

The disadvantage is that the driving force generated by this tuning method is very small, so the mechanism must be in a vacuum environment, and the crystal cannot be baked at high temperature, so it is not conducive to the exhaust and degassing of the whole tube, reducing the life of the magnetron and Work stability; the tuning mechanism needs a higher voltage to drive, generally around 500-1000V, if the mechanism is installed in a vacuum environment, it must introduce lead wires, and it needs to be insulated from the shell, and the insulator and the shell Sealing is more difficult, and the sealing is also a prone part to generate air leakage, which is a potential danger to the reliability of the magnetron.

[0007] None of the above tuning methods in the prior art can compensate the temperature, that is, at high temperature and low temperature, the frequency or tuning bandwidth will change greatly due to the thermal expansion of the material, which reduces the reliability of the magnetron

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