CN215869731U

CN215869731U - Cavity type filter and self-locking tuning screw for cavity type filter

Info

Publication number: CN215869731U
Application number: CN202122475087.6U
Authority: CN
Inventors: 赵嘉炜; 周亮
Original assignee: Suzhou Xiecheng Microwave Technology Co ltd
Current assignee: Suzhou Xiecheng Microwave Technology Co ltd
Priority date: 2021-10-14
Filing date: 2021-10-14
Publication date: 2022-02-18
Anticipated expiration: 2031-10-14

Abstract

The utility model discloses a cavity type filter and a self-locking tuning screw for the cavity type filter, wherein the tuning screw comprises a screw thread part, the screw thread part is in a retracted state from top to bottom, and the outer side wall of the screw thread part is provided with a thread; the upper surface of the screw tooth part is provided with a sunken structure, the peripheral side wall of the sunken structure is provided with one or more through grooves, the through grooves penetrate through the inner side wall and the outer side wall of the screw tooth part, and the through grooves enable the upper end surface of the screw tooth part to form a gap; the peripheral side wall of the concave structure on the screw tooth part can deform inwards under the action of external force. The tuning screw rod with the band-pass groove type thread part has a self-locking structure, a protruding metal sleeve does not need to be additionally arranged on the cover plate, the processing technology is simple, the space size is small, the weight of a product is reduced, the tuning is convenient, the manufacturing cost is reduced, and the product performance is more excellent.

Description

Cavity type filter and self-locking tuning screw for cavity type filter

Technical Field

The utility model relates to the field of filters, in particular to a cavity type filter and a self-locking tuning screw for the cavity type filter.

Background

In recent years, with the rapid development of scientific technology, wireless communication systems have been advanced significantly in the rapid development of microwave and millimeter wave technologies. With the development of communication technology, frequency spectrum resources are more and more rare, the intervals between frequency spectrums are more and more close, and corresponding interference is also more and more large, and a filter is a typical frequency selection device, and the quality of the performance of the filter directly affects the quality of the whole communication system, so that a cavity filter in a communication base station becomes an important part of wireless communication.

The cavity filter is a microwave filter adopting a resonant cavity structure, and one cavity can be equivalent to an inductor and a capacitor connected in parallel, so that a resonant level is formed, and the microwave filtering function is realized; compared with microwave filters with other properties, the cavity filter has the advantages of firm structure, stable and reliable performance, smaller volume, moderate Q value, far high-end parasitic passband and good heat dissipation. Therefore, the application of the cavity filter is very common in each large communication base station. With the continuous update of communication technology, base station equipment is gradually developing toward miniaturization, light weight and low loss, so the requirements of cavity filters are also improved.

The cavity filter mainly comprises a cavity, a resonator, a cover plate covered on the cavity, a tuning screw, a locking nut, a set screw and the like, wherein a resonance column is arranged on the cavity, a screw through hole for installing the set screw and the tuning screw is arranged on the cover plate, the tuning screw extends into the cavity from the cover plate surface, the tuning screw is fastened through the nut, but the tuning screw needs to be pre-assembled on the cover plate in advance, so that the production cost is high, the efficiency is low, in addition, the nut needs to be locked constantly during tuning frequency, the debugging time is long, and the debugging efficiency is low; however, the current cavity filter also has a part of self-locking screws, but the self-locking screw structure applied in the current industry is basically that the metal sleeve with the height larger than that of the cover plate is pre-installed on the cavity cover plate, then the screw rod is fixed to achieve the self-locking effect by being clamped with the metal sleeve, as shown in fig. 7, but the metal sleeve needs enough space to be installed, which is not beneficial to the miniaturization of the cavity filter, and the cost of the screw rod is relatively high.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems in the prior art, the utility model provides a cavity type filter and a self-locking tuning screw for the cavity type filter, the processing technology is simple, the used space size is small, the tuning is convenient, the manufacturing cost is reduced, the product weight is reduced, the product performance is more excellent on the same space size, the product competitive advantage can be greatly improved, and the technical scheme is as follows:

in one aspect, the present invention provides a cavity filter, including:

the filter cavity is provided with a hollow inner cavity, and the upper end surface of the filter cavity is of an open structure;

the resonators are arranged in the inner cavity of the filter cavity, and the number of the resonators is one or more;

the cover plate is arranged on the upper end face of the filter cavity and provided with through holes which correspond to the resonators one by one, the through holes and the resonators are arranged in an up-down opposite mode, and inner threads are arranged on the inner wall of each through hole;

the tuning screws correspond to the through holes in the cover plate one by one;

the tuning screw is characterized by comprising a screw tooth part, wherein the screw tooth part is in a retracted state from top to bottom, an external thread matched with an internal thread on the inner wall of the through hole is arranged on the outer side wall of the screw tooth part, a recessed structure is arranged on the upper surface of the screw tooth part, one or more through grooves are arranged on the peripheral side wall of the recessed structure, and the through grooves penetrate through the inner side wall and the outer side wall of the peripheral side wall;

when the peripheral side wall of the sunken structure on the thread part is screwed into the through hole of the cover plate, the peripheral side wall is deformed inwards.

Furthermore, the number of the through grooves is multiple, the through grooves enable the upper end faces of the thread parts to form notches, and the height of the through grooves in the vertical direction is smaller than that of the thread parts.

Furthermore, the sunken structure is a round blind hole, the number of the through grooves is four or two, and the through grooves enable the upper end surfaces of the thread parts to form equally-divided gaps.

Further, the ratio range of the height of the through groove in the vertical direction to the overall height of the thread part is 1: 1.1 to 1: 10, or 1: 1.2 to 1: 8, or 1: 1.3 to 1: 6, or 1: 1.5 to 1: 4.

further, the through grooves are vertically arranged; the through groove is of an equal-width structure, or a structure with a wide upper part and a narrow lower part, or a structure with a narrow upper part and a wide lower part.

Further, the tuning screw further comprises a columnar boss, the boss is arranged on the lower surface of the thread part and extends downwards, and the diameter of the boss is smaller than the outer diameter of the thread part.

Furthermore, the boss and the thread part are coaxially arranged, and the lower end of the boss extends into the resonant cavity of the corresponding resonator.

Furthermore, the outer edge of the lower end of the boss is provided with a fillet.

Furthermore, the tuning screw is made of copper.

On the other hand, the utility model provides a self-locking tuning screw for a cavity type filter, which comprises a screw thread part, wherein the screw thread part is in a retracted state from top to bottom, and the outer side wall of the screw thread part is provided with a thread; the upper surface of the screw tooth part is provided with a sunken structure, the peripheral side wall of the sunken structure is provided with one or more through grooves, the through grooves penetrate through the inner side wall and the outer side wall of the screw tooth part, and the through grooves enable the upper end surface of the screw tooth part to form a gap;

the peripheral side wall of the concave structure on the screw tooth part can deform inwards under the action of external force.

The technical scheme provided by the utility model has the following beneficial effects:

a. the tuning screw does not need to be assembled on the cover plate in advance, so that the production cost is reduced;

b. for the application occasions with less frequency tuning amount, the tuning screws do not need to extend into the corresponding resonators at the lower ends;

c. the self-locking is realized by adopting a self-structure without the need of nut fastening;

d. the metal sleeve with a certain height is not required to be mounted on the cover plate to realize self-locking, so that the miniaturization of the cavity filter is realized.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic cross-sectional view of a cavity filter provided by an exemplary embodiment of the present disclosure;

fig. 2 is a schematic perspective view of a tuning screw of a cavity filter provided in an exemplary embodiment of the present disclosure;

FIG. 3 is a schematic top view of a tuning screw provided in an exemplary embodiment of the present disclosure;

FIG. 4 is a schematic side view of a tuning screw provided in an exemplary embodiment of the present disclosure;

FIG. 5 is a schematic perspective view of a tuning screw with bosses provided in an exemplary embodiment of the present disclosure;

fig. 6 is a schematic cross-sectional view of a cavity filter having the tuning screw of fig. 5 provided in an exemplary embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of a screw self-locking structure implemented by arranging a metal sleeve with a certain height on a cover plate in the prior art.

Wherein the reference numerals include: 1-filter cavity, 2-cover plate, 3-resonator, 4-tuning screw, 41-thread part, 42-through groove, 43-base part, 44-boss, 45-peripheral side wall.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the utility model described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.

In one embodiment of the present invention, there is provided a cavity filter, as shown in fig. 1, including:

the filter cavity 1 is provided with a hollow inner cavity, and the upper end surface of the filter cavity is of an open structure;

the resonators 3 are arranged in the inner cavity of the filter cavity 1, the number of the resonators is one or more, the bottom of each resonator 3 is fixed on the upper surface of the bottom wall of the filter cavity 1, and the resonator is provided with a hollow resonant cavity;

the cover plate 2 is arranged on the upper end face of the filter cavity 1 and is provided with through holes corresponding to the resonators 3 one by one, internal threads are arranged on the inner walls of the through holes, and the through holes and the resonators 3 are arranged in a vertically opposite mode when the cover plate 2 covers the filter cavity 1;

the tuning screws 4 correspond to the through holes in the cover plate 2 one by one, and the tuning screws 4 in the embodiment of the utility model can be not assembled on the cover plate in advance, so that the production cost is reduced; on the other hand, the tuning screw 4 in the embodiment can realize the tuning of the frequency without extending the lower end into the corresponding resonator 3; on the other hand, the screw has a self-locking function without being fastened through a nut, so that a metal sleeve with a certain height is not required to be mounted on the cover plate 2 to realize self-locking, and the miniaturization of the cavity filter is realized. The concrete structure is as follows:

as shown in fig. 2 and 3, the tuning screw 4 includes a thread portion 41 and a base portion 43 integrally formed at a bottom of the thread portion 41, the thread portion 41 has an annular three-dimensional structure, an outer side wall of the thread portion 41 is provided with an external thread engaged with an internal thread of the inner wall of the through hole, an outer side wall of the base portion 43 may be provided with an external thread, and the base portion 43 may have a plate structure for blocking a lower opening of the annular hollow portion of the thread portion 41 or a plate structure having a through hole structure. In particular, said base portion 43 is arranged above the corresponding resonator 3, as shown in fig. 1. The thread part 41 does not need to be assembled on the cover plate in advance, and only the thread part 41 needs to be screwed into a through hole in the cover plate 2 during assembly, and the frequency is tuned by adjusting the depth of the thread part 41 in the through hole, specifically, the lower the thread part 41 is screwed down, the lower the tuned frequency is, and the higher the frequency is otherwise.

The tuning screw 4 in this embodiment has a self-locking function, and as shown in fig. 4, the thread portion 41 is in a retracted state from top to bottom, for example, the difference between the upper and lower widths is within 0.5-2 mm. The manufacturing method comprises the following steps: selecting a cylinder with the inverted cone structure, performing threading operation on the outer surface of the cylinder, drilling a blind hole downwards on the surface of one end with a larger outer diameter to enable the upper surface of the thread part 41 to be provided with a recessed structure, then processing a through groove 42 on the peripheral side wall 45 of the recessed structure, wherein the through groove 42 penetrates through the inner side wall and the outer side wall of the peripheral side wall 45, and a notch is formed in the upper end surface of the thread part 41. The depth of the blind hole is approximately equal to the upper and lower heights of the through groove 42, the deeper the blind hole is, the thinner the thickness of the base part 43 at the bottom of the thread part 41 is, and the depth of the blind hole is required to meet the requirement that when the tuning screw 4 is screwed downwards into the through hole on the cover plate 2, the base part 43 can be deformed under the cooperation of the through groove 42, namely, the original planar structure of the tuning screw is changed, and certainly, the micro-deformation of a metal plane is realized; after the deformation, the base part 43 has a stress function of restoring to a plane, and the stress function enables a plurality of peripheral side walls 45 adjacent to the through groove 42 to have larger acting force for propping up the inner wall of the through hole inside the through hole of the cover plate 2, so as to realize the self-locking function of the tuning screw, namely when the screw thread part 41 is screwed into the screw hole of the cover plate, because the screw thread part 41 has an inverted taper, when the screw rotates downwards, the internal thread of the through hole of the cover plate 2 can force the external thread of the screw thread part 41 to deform inwards, wherein the external thread of the screw thread part 41 is divided into sections by the through groove 42, so that the inward deformation of the peripheral side walls 45 becomes possible and is easier to realize; meanwhile, the base part 43 is deformed to generate a reaction force, so that the tuning screw can generate outward tension to prop up the inner wall of the through hole of the cover plate 2, and the tuning screw 4 can be self-locked, the tuning screw 4 is usually made of a material with good elasticity, such as copper, and the cover plate 2 and the tuning screw 4 are mutually engaged through threads (threads), so that the tuning screw 4 can rotate up and down; optionally, the external thread on the thread portion 41 may be further configured to be of a discontinuous design, that is, the external thread is at least disconnected by one, for example, disconnected by 0.8 thread, 1.2 thread or other non-integral thread, and through the structure of the external thread on the thread portion 41, a screw self-locking function may be achieved, and it is not necessary to install a protruding metal sleeve on the cover plate to match the thread portion 41 in a self-locking manner, therefore, in this embodiment, the upper surface of the tuning screw 4 installed on the cover plate 2 is substantially flush with the upper surface of the cover plate 2, and even retracts into the through hole on the cover plate 2, so that the volume of the cavity filter is further miniaturized.

In an embodiment of the present invention, the number of the through grooves 42 is plural, the through grooves 42 form notches on the upper end surfaces of the thread parts 41, the height of the through grooves 42 in the vertical direction is smaller than the height of the thread parts 41, the number of the through grooves 42 determines the number of the divided peripheral side walls 45, and the larger the number, the more the inward deformation is likely to occur; as shown in fig. 3, the number of the through grooves 42 is four, the distances between adjacent through grooves 42 are equal, and the through grooves 42 form a quartered notch on the upper end surface of the thread portion 41. It should be noted that the number of the through slots 42 is not limited to four, nor to equal parts, and it should be understood that the number and the relative position relationship of the specific arrangement can be freely designed according to the actual requirement, and meanwhile, the through slots are vertically arranged or obliquely arranged, and the widths of the through slots are equal in width up and down or wide in width up and narrow down or wide in width down and wide in width down can be adjusted.

The design of the through groove 42 on the thread part 41 realizes the self-locking function of the tuning screw 4, and for the application occasions with less frequency tuning amount, an extension screw rod does not need to be arranged to extend into the resonator 3, and the ratio range of the height of the through groove 42 in the vertical direction to the height of the thread part 41 is 1: 1.1 to 1: 10, or 1: 1.2 to 1: 8, or 1: 1.3 to 1: 6, or 1: 1.5 to 1: 4, it should be understood that the height of the through slots 42 may be designed depending on the requirements of the actual tuning frequency.

In this embodiment, the tuning screw 4 is made of copper, the inner wall of the thread portion 41 may be a smooth structure, and both the upper surface and the lower surface of the base portion 43 may be smooth surfaces. In another embodiment, the lower surface of the base portion 43 is provided with a convex or concave spiral line structure, the frequency tuning stability of the cavity filter can be obviously improved under the condition that the number of turns of the spiral line is greater than 3 turns, the more the number of turns of the spiral line is, the higher the frequency tuning stability is, the difficulty of the processing technology is considered, and the number of turns of the spiral line is preferably 5 turns.

In another embodiment of the present invention, different from the above-mentioned embodiment, as shown in fig. 5, the tuning screw 4 further includes a cylindrical boss 44, the boss 44 is disposed on the lower surface of the base part 43 and extends downward, the diameter of the boss 44 is smaller than the outer diameter of the thread part 41, the boss is a smooth straight rod, as shown in fig. 6, the lower end of the boss 44 extends into the resonant cavity of the corresponding resonator 3, and this applicable frequency tuning range is wider than that of the previous embodiment.

As shown in fig. 5 and 6, the boss 44 is substantially coaxial with the thread portion 41, and in a preferred embodiment, the outer edge of the lower end of the boss 44 is provided with a rounded corner, so that the tuning screw 4 is not easy to change abruptly in tuning the frequency, and can be adjusted to the target frequency more smoothly. Similarly to the previous embodiment, the lower surface of the base part 43 is provided with a raised or recessed spiral line structure at the periphery of the boss 44, so that the frequency tuning stability of the cavity filter can be improved, and the number of turns of the spiral line is preferably 3.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing is directed to embodiments of the present application and it is noted that numerous modifications and adaptations may be made by those skilled in the art without departing from the principles of the present application and are intended to be within the scope of the present application.

Claims

1. A cavity filter comprising:

the filter cavity (1) is provided with a hollow inner cavity, and the upper end surface of the filter cavity is of an open structure;

resonators (3) arranged in the inner cavity of the filter cavity (1), the number of which is one or more;

the cover plate (2) is arranged on the upper end face of the filter cavity (1) and is provided with through holes which correspond to the resonators (3) one by one, the through holes and the resonators (3) are arranged in an up-down opposite mode, and internal threads are arranged on the inner wall of each through hole;

the tuning screws (4) correspond to the through holes in the cover plate (2) one by one;

the tuning screw is characterized in that the tuning screw (4) comprises a screw tooth part (41), the screw tooth part (41) is in a retracted state from top to bottom, an external thread matched with an internal thread of the inner wall of the through hole is arranged on the outer side wall of the screw tooth part (41), a recessed structure is arranged on the upper surface of the screw tooth part (41), one or more through grooves (42) are formed in the peripheral side wall (45) of the recessed structure, and the through grooves (42) penetrate through the inner side wall and the outer side wall of the peripheral side wall (45);

when the peripheral side wall (45) of the concave structure on the thread part (41) is screwed into the through hole of the cover plate (2), the peripheral side wall (45) deforms inwards.

2. The cavity filter according to claim 1, wherein the number of the through grooves (42) is plural, the through grooves (42) form notches on upper end surfaces of the thread parts (41), and the height of the through grooves (42) in the vertical direction is smaller than the height of the thread parts (41).

3. The cavity filter according to claim 2, wherein the recessed structure is a circular blind hole, the number of the through grooves (42) is four or two, and the through grooves (42) form equally-divided gaps on the upper end surfaces of the thread parts (41).

4. The cavity filter according to claim 2, wherein the ratio of the height of the through groove (42) in the vertical direction to the overall height of the thread part (41) is in the range of 1: 1.1 to 1: 10, or 1: 1.2 to 1: 8, or 1: 1.3 to 1: 6, or 1: 1.5 to 1: 4.

5. the cavity filter according to claim 2, wherein the through slots (42) are arranged vertically; the through grooves (42) are of an equal-width structure or a structure with a wide top and a narrow bottom or a structure with a narrow top and a wide bottom.

6. The cavity filter according to claim 1, wherein the tuning screw (4) further comprises a cylindrical boss (44), the boss (44) is disposed on a lower surface of the thread part (41) and extends downward, and a diameter of the boss (44) is smaller than an outer diameter of the thread part (41).

7. The cavity filter according to claim 6, wherein the boss (44) is coaxially disposed with the thread part (41), and a lower end of the boss (44) protrudes into a resonance cavity of the corresponding resonator (3).

8. The cavity filter according to claim 6, wherein the outer edge of the lower end of the boss (44) is provided with a rounded corner.

9. A cavity filter as claimed in any one of claims 1 to 8, wherein the tuning screw (4) is of copper.

10. The self-locking tuning screw for the cavity type filter is characterized by comprising a screw thread part (41), wherein the screw thread part (41) is in a retracted state from top to bottom, and the outer side wall of the screw thread part (41) is provided with threads; the upper surface of the screw part (41) is provided with a sunken structure, one or more through grooves (42) are arranged on the peripheral side wall (45) of the sunken structure, the through grooves (42) penetrate through the inner side wall and the outer side wall of the screw part (41), and the through grooves (42) enable the upper end surface of the screw part (41) to form a gap;

peripheral side wall (45) of sunk structure on screw tooth portion (41) can inwards take place deformation under the exogenic action.

11. The self-locking tuning screw according to claim 10, wherein the tuning screw (4) further comprises a cylindrical boss (44), the boss (44) being provided on a lower surface of the thread part (41) and extending downward, the boss (44) having a diameter smaller than an outer diameter of the thread part (41).