Cavity filter

Abstract

The utility model discloses a cavity filter, which comprises a cavity, a cover plate, a resonator, a tuning screw and a tuning nut, the cover plate is arranged at the open end of the cavity, the resonator is arranged in the cavity, a plurality of threaded holes are arranged on the cover plate, the tuning screw is in threaded connection in the threaded holes, and the tuning nut is arranged in the cavity. The tuning nut is in threaded connection with the tuning screw and abuts against the outer side wall of the cover plate, the outer side wall of the cover plate is provided with a first tin bath located on the outer circle of the threaded hole and communicated with the threaded hole, and the tin ring is arranged in the first tin bath; through the structure, the tin ring can smoothly fill the thread combination seam during heating, and an annular closed shielding ring is formed after dissolving and bonding, so that the electrical performance is improved.

Description

Technical Field

[0001] This utility model relates to the field of filters, and in particular to a cavity filter. Background Technology

[0002] A cavity filter typically consists of a cavity, a cover plate, a resonator, a tuning screw, and a tuning nut. The tuning screw is pre-threaded through the tuning screw nut and then rotated through the threads on the cover plate to extend into the cavity. The tuning screw is repeatedly tightened according to the changes in the vector network analyzer graph until the filter's performance meets design requirements. Finally, the nut is tightened, relying on the friction between the tuning screw nut and the cover plate to secure the tuning screw. UV adhesive is then applied to prevent loosening. To prevent loosening of the tuning screw and cover plate from affecting electrical performance, a slot is created in the tuning nut. After adjustment, solder paste is applied into the slot. The solder paste melts and fills the gaps between the tuning nut and the tuning screw, and between the tuning screw and the cover plate, thus achieving a secure fit.

[0003] However, this approach has the following drawbacks:

[0004] 1. The tuning screw has poor anti-loosening effect and is prone to loosening and displacement under temperature cycling, vibration and impact.

[0005] 2. At the same time, the tuning nut is only used to prevent loosening, which implicitly increases the product quality;

[0006] 3. Applying UV adhesive increases the product's processing steps and costs;

[0007] 4. Slotted nuts are more expensive because the small gap between the threads makes it difficult for solder paste to penetrate into the gap between the tuning screw and the cover plate.

[0008] Therefore, there is an urgent need for a new type of cavity filter to solve the above problems. Utility Model Content

[0009] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a cavity filter.

[0010] The technical solution adopted by one embodiment of this utility model to solve its technical problem is as follows: a cavity filter, including a cavity, a cover plate, a resonator, a tuning screw and a tuning nut. The cover plate is installed at the opening end of the cavity, the resonator is installed in the cavity, the cover plate is provided with a plurality of threaded holes, the tuning screw is threadedly connected to the threaded holes, the tuning nut is threadedly connected to the tuning screw and abuts against the outer side wall of the cover plate, and also includes a solder ring. The outer side wall of the cover plate is provided with a first solder groove located on the outer ring of the threaded hole and communicating with the threaded hole, and the solder ring is disposed in the first solder groove.

[0011] As one of the preferred embodiments of this utility model, the first solder bath is located within the longitudinal projection of the tuning nut, so that the upper opening of the first solder bath is closed when the tuning nut abuts against the cover plate.

[0012] In one of the preferred embodiments of this utility model, the depth of the first tin bath is greater than the thickness of the tin ring.

[0013] As one of the preferred embodiments of this utility model, the tuning nut is provided with a second solder groove that communicates with the first solder groove.

[0014] As one of the preferred embodiments of this utility model, the first tin bath and / or the second tin bath are configured as a countersunk trough, a chamfered trough, or an inverted trapezoidal trough.

[0015] The beneficial effects of this utility model are as follows: A cavity filter includes a cavity, a cover plate, a resonator, a tuning screw, and a tuning nut. The cover plate is installed at the open end of the cavity, and the resonator is installed inside the cavity. The cover plate has several threaded holes. The tuning screw is threaded into the threaded holes, and the tuning nut is threaded onto the tuning screw and abuts against the outer wall of the cover plate. It also includes a solder ring. The outer wall of the cover plate has a first solder groove located on the outer ring of the threaded holes and communicating with the threaded holes. The solder ring is placed in the first solder groove. Through the above structure, the solder ring can smoothly fill the threaded joint when heated, and after melting, it forms a closed annular shielding ring, improving electrical performance. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0017] Figure 1 This is a cross-sectional view of a cavity filter;

[0018] Figure 2 This is a partial cross-sectional view of a cavity filter. Detailed Implementation

[0019] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0020] In the description of this utility model, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly specifying the number of indicated technical features or their sequential relationship.

[0021] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] In this utility model, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to a fixed connection, a detachable connection, or an integral molding; they can refer to a mechanical connection; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0023] Reference Figures 1 to 2 A cavity filter includes a cavity 10, a cover plate 20, a resonator 30, a tuning screw 40, and a tuning nut 50. The cover plate 20 is installed at the open end of the cavity 10, the resonator 30 is installed inside the cavity 10, the cover plate 20 is provided with a plurality of threaded holes 21, the tuning screw 40 is threaded into the threaded holes 21, the tuning nut 50 is threaded into the tuning screw 40 and abuts against the outer side wall of the cover plate 20, and also includes a solder ring 60. The outer side wall of the cover plate 20 is provided with a first solder groove 70 located on the outer ring of the threaded holes 21 and communicating with the threaded holes 21, and the solder ring 60 is disposed in the first solder groove 70.

[0024] Reference Figure 1 In this utility model, during production, the resonator 30 is first installed into the cavity 10, and then the tuning screw 40 is threaded into the threaded hole 21 of the cover plate 20. The tuning screw 40 is repeatedly tightened according to the changes in the vector network analyzer graph until the filter performance meets the design requirements. Then, the solder ring 60 is fitted onto the tuning screw 40 and falls into the first solder bath 70, and the tuning nut 50 is threaded onto the tuning screw 40 until it abuts against the outer wall of the cover plate 20. At this point, the solder ring 60 is sealed within the first solder bath 70 by the cover plate 20 and the tuning nut 50. Finally, the cavity filter is placed in a high-temperature furnace for heating to melt the solder ring 60. (Refer to...) Figure 2 By controlling the heating time, it can be ensured that some of the tin solution remains in the first tin bath 70 and forms a closed annular shielding ring after melting. The remaining tin solution seeps in through the gap between the tuning screw 40 and the threaded hole 21 of the cover plate 20, tightly connecting the tuning screw 40 and the cover plate 20 together.

[0025] Reference Figures 1-2 In some embodiments, the first solder bath 70 is located within the longitudinal projection of the tuning nut 50, so that the upper opening of the first solder bath 70 is closed when the tuning nut 50 abuts against the cover plate 20.

[0026] Reference Figures 1-2 In some embodiments, the depth of the first solder bath 70 is greater than the thickness of the solder ring 60. This arrangement can prevent the upper end face of the solder ring 60 from being higher than the upper end face of the cover plate 20, thus avoiding affecting the installation of the tuning nut 50.

[0027] In some embodiments, the tuning nut 50 is provided with a second solder groove that communicates with the first solder groove 70. In this embodiment, by providing the second solder groove, the thickness of the solder ring 60 can be greater than the depth of the first solder groove 70, so that at least a portion of the upper end of the solder ring 60 is located in the second solder groove. After the solder ring 60 melts, it can not only fill the thread gap between the tuning screw 40 and the cover plate 20, but also fill the gap between the tuning nut 50 and the cover plate 20, thereby further improving the stability of the cavity filter.

[0028] Reference Figures 1-2 In some embodiments, the first tin bath 70 and / or the second tin bath are configured as a countersunk trough, a chamfered trough, or an inverted trapezoidal trough.

[0029] The advantages of this invention are: the above structure allows the tin ring to fill the threaded joint smoothly during heating, and after melting, it forms a closed annular shielding ring, thus improving electrical performance.

[0030] Of course, this utility model is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of this utility model. All such equivalent modifications and substitutions are included within the scope defined by the claims of this application.

Claims

1. A cavity filter, comprising a cavity (10), a cover plate (20), a resonator (30), a tuning screw (40), and a tuning nut (50), wherein the cover plate (20) is installed at the open end of the cavity (10), the resonator (30) is installed inside the cavity (10), the cover plate (20) is provided with a plurality of threaded holes (21), the tuning screw (40) is threaded into the threaded holes (21), and the tuning nut (50) is threaded into the tuning screw (40) and abuts against the outer side wall of the cover plate (20), characterized in that: It also includes a tin ring (60), and a first tin groove (70) is provided on the outer wall of the cover plate (20) and located on the outer ring of the threaded hole (21) and communicating with the threaded hole (21). The tin ring (60) is disposed in the first tin groove (70).

2. The cavity filter of claim 1, wherein: The first solder bath (70) is located within the longitudinal projection of the tuning nut (50) so that the upper opening of the first solder bath (70) is closed when the tuning nut (50) abuts against the cover plate (20).

3. The cavity filter of claim 1, wherein: The depth of the first tin bath (70) is greater than the thickness of the tin ring (60).

4. The cavity filter of claim 1, wherein: The tuning nut (50) is provided with a second tin groove that communicates with the first tin groove (70).

5. The cavity filter of claim 4, wherein: The first tin bath (70) and / or the second tin bath are configured as a countersunk trough, a chamfered trough or a trapezoidal trough.

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