Cavity filter frequency adjustment mechanism

Abstract

The present invention provides a frequency governing mechanism for cavum filter, which comprises of cavum body, inner and outer medium and connecting rod moved by gearing. The outer medium is placed in cavum body, the connecting rod is placed in outer medium, and the inner medium is mounted on connecting rod. Wherein, a stretch device capable of making connecting rod, inner medium axes and cavum body or / and outer medium concentric automatically is set on the connecting rod. The stretch device can be set in corresponding groove of cavum body, cover board or gearing, which comprises of at least two elastic members symmetric to center of vacuum, the front end of each member has stretch working surface matched to connecting rod, the rear end is arc surface capable of swing automatically along inner wall of groove and stretched touch with inner wall of groove. A pair of elastic double nuts space adjusting member is set on the lead screw. The present invention can eliminate assembly error, ensure the motor lead screw, connecting rod, vacuum body, inner or outer medium and cover board is concentric, improve the rigidity of connecting rod.

Description

【Technical field】 [0001] The invention relates to the technical field of cavity filters in base stations of mobile communication systems, in particular to a tuning mechanism for automatically tuning the frequency relationship of the filter and / or the coupling efficiency factor between central conductors in the filter. 【Background technique】 [0002] The cavity filter is one of the common components in the mobile communication system. Due to the manufacturing errors of the parts that make up the cavity filter, it must be assembled through adjustment. There are many kinds of tuning mechanisms for cavity filters, such as ordinary screw tuning mechanisms, self-locking screw tuning mechanisms, and automatic tuning mechanisms. [0003] US 6255922 B1 patent has disclosed an automatic tuning mechanism for a cavity filter, such as figure 1 As shown, the cavity filter includes a cavity closed by the cover plate a, the connecting rod b passes through the entire cavity c, and the lower...

AI Technical Summary

Problems solved by technology

Therefore, the requirements for the axial degree of the processing of the connecting rod b are relatively high in manufacturing. Even so, the end of the connecting rod b is still easy to deviate from the axis line during operation, which will cause the screw of the motor d and the connecting rod b, and the connecting rod b and the Seizure between cover plates a

Moreover, in the above structure, according to the requirements of use, the connecting rod b cannot be made of metal materials, and requires low dielectric constant, low loss and certain rigidity. Therefore, when the cavity height of the cavity filter is relatively large, the connecting rod b needs to use hollow thin-walled components, so the rigidity of the connecting rod b in the above structure is poor, and there is no good practicability

In addition, since the connecting rod b is driven to rotate by the motor d connected to its lower end, when moving close to the motor d, it needs to rely on the rebound force of the spring f set at the upper end to realize its adjustment. When the length of the connecting rod b is relatively large, This kind of feedback will produce hysteresis, affect the use effect, and the adjustment range is very small

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