CN101599569B - Coupling structure and coaxial-cavity filter - Google Patents

Abstract

The invention discloses a coupling structure and a coaxial cavity filter using the coupling structure. The coupling structure comprises: a coupling base, a coupling part installed on the coupling base, and the first coupling end of the coupling part is separated from the second coupling part of the coupling base. protruding from one surface, the second coupling end of the coupling part protrudes from the second surface of the coupling base, the first surface is opposite to the second surface, and the coupling base further includes: a first slot and a second slot on the coupling base The coupling component is fixedly connected to the coupling base through the first coupling slot or the second coupling slot, so that the coupling state of the coupling structure can be adjusted according to the position of the coupling component. The coupling structure of the present invention can easily realize at least two different coupling amounts, thereby adapting to different application scenarios.

Description

Coupling Structures and Coaxial Cavity Filters

technical field

The invention relates to the technical field of communication, in particular to a coupling structure and a coaxial cavity filter using the coupling structure.

Background technique

With the rapid development of mobile communication, the communication system has higher and higher requirements for communication quality. In order to improve the utilization rate of spectrum resources and prevent signals in the frequency band from being interfered by other signals, the communication system strengthens the suppression of signals in adjacent frequency bands. , so the wireless communication system has higher requirements on the performance of the suppression filter, duplexer and combiner, and the duplexer and combiner are usually composed of coaxial cavity filters. In order to improve the rejection of the filter, it is usually realized by adding a coupling structure in the coaxial cavity filter.

Referring to FIG. 1 , FIG. 1 is a schematic diagram of a coaxial cavity filter in the prior art. As shown in the figure, the coaxial cavity filter includes a plurality of resonant cavities, including a first resonant cavity 10, a second resonant cavity 20, a first resonator 11 located in the first resonant cavity and a resonator located in the first resonant cavity The second resonator 21 in the second resonant cavity. The coaxial cavity filter also includes a coupling structure, the coupling structure is composed of a support 30, a mounting screw 40 and a coupling flange 50, wherein the support 30 is installed on the isolation between the first resonant cavity 10 and the second resonant cavity 20 On the wall 25 , the coupling flange 50 is fixed on the support 30 through the mounting screw 40 .

The inventor found in the process of realizing the present invention that the coupling structure in the prior art cannot adjust the coupling amount between the coupling structure and the resonator after it is installed in the coaxial cavity filter, so it cannot adapt to more application scenarios .

Contents of the invention

The invention provides a coupling structure and a coaxial cavity filter including the coupling structure, which can provide various coupling quantities.

The coupling structure provided by the embodiment of the present invention includes:: a coupling base, a coupling component installed on the coupling base, the first coupling end of the coupling component protrudes from the first surface of the coupling base, and the second coupling end of the coupling component protrudes from the first surface of the coupling base. Protruding from the second surface of the coupling base, the first surface and the second surface are opposite, the coupling base also includes: a first card slot and a second card slot on the coupling base, and the coupling part can optionally pass through the first card slot or The second card slot is fixedly connected with the coupling base, so that the coupling state of the coupling structure can be adjusted according to the position of the coupling component.

An embodiment of the present invention also provides a coaxial cavity filter including the coupling structure, including: a first resonant cavity and a second resonant cavity, the first resonant cavity and the second resonant cavity are adjacent, and the first resonant cavity includes The first resonator, the second resonator includes the second resonator, the coaxial cavity filter also includes a coupling structure, the coupling structure is detachably installed on the partition wall between the first resonant cavity and the second resonant cavity, The first coupling end of the coupling component is coupled to the first resonator, and the second coupling end of the coupling component is coupled to the second resonator. The coupling structure also includes: a coupling base, a coupling component installed on the coupling base, and the first coupling end of the coupling component. The coupling end protrudes from the first surface of the coupling base, the second coupling end of the coupling component protrudes from the second surface of the coupling base, the first surface and the second surface are opposite, and the coupling base further includes: The first card slot and the second card slot, the coupling component can be fixedly connected to the coupling base through the first card slot or the second card slot, so that the coupling state of the coupling structure can be adjusted according to the position of the coupling component.

In the embodiment of the coupling structure of the present invention, the coupling component can be fixed in the first card slot or the second card slot, and when the coupling component is fixed in the first card slot or the second card slot, the coupling component can be fixed on the coupling base different positions on the top, so that the coupling state of the coupling structure can be adjusted according to the position of the coupling component. Compared with the coupling structure in the prior art, the embodiment of the present invention can easily realize at least two different coupling amounts, So as to adapt to different application scenarios.

Description of drawings

FIG. 1 is a schematic diagram of a coaxial cavity filter in the prior art;

Fig. 2 is a flowchart of the first embodiment of the coupling structure provided by the present invention;

Fig. 3 is a flow chart of the second embodiment of the coupling structure provided by the present invention;

Fig. 4 is a schematic diagram of the first embodiment of the coaxial cavity filter provided by the present invention;

Fig. 5 is a schematic diagram of a second embodiment of the coaxial cavity filter provided by the present invention.

Detailed ways

The invention provides a coupling structure and a coaxial cavity filter comprising the coupling structure. In order to better understand the technical solutions of the present invention, the embodiments provided by the present invention will be described in detail below in conjunction with the accompanying drawings.

Referring to FIG. 2 , FIG. 2 is a schematic diagram of a first embodiment of a coupling structure provided by the present invention.

As shown in FIG. 2( a ), the coupling structure in the embodiment of the present invention includes: a coupling base 100 , and a coupling component disposed on the coupling base 100 . The coupling base 100 includes a first surface 110, a second surface 120 opposite to the first surface 110, a third surface 130 intersecting the first surface 110 and the second surface 120, and a fourth surface 140 opposite to the third surface 130, The first coupling end 210 of the coupling component protrudes from the first surface 110 of the coupling base 100 , and the second coupling end 220 of the coupling component protrudes from the second surface 120 of the coupling base 100 . The embodiment of the coupling structure of the present invention also includes: a first card slot 101 and a second card slot 102 on the coupling base 100, the coupling component can be selectively fixed in the first card slot 101 or the second card slot 102, and when When the coupling component is fixed in the first slot 101 and the second slot 102 , the positions of the coupling component on the coupling base are different. In the embodiment of the present invention, by fixing the coupling component in the first slot 101 or the second slot 102 , the coupling status of the coupling structure can be adjusted according to the position of the coupling component. Compared with the coupling structure in the prior art, the embodiment of the present invention can easily realize at least two different coupling amounts, so as to adapt to different application scenarios. In the embodiment of the coupling structure of the present invention, when installing the coupling component on the coupling base 100, it is only necessary to snap the coupling component into the first slot 101, the installation process is simple, and the installation efficiency can be improved.

In the embodiment of the present invention, a guiding component is further provided on the third surface 130 of the coupling base, wherein the third surface 130 intersects with the first surface 110 and the second surface 120 . In the embodiment of the present invention, the guide part can extend along the direction perpendicular to the first surface 110, and can also extend along the direction parallel to the first surface 110 and the second surface 120. In the embodiment of the present invention, the guide part is a guide The groove 131 , the guiding groove 131 extends along a direction parallel to the first surface 110 and the second surface 120 , of course the guiding component is not limited to the guiding groove, and may also be a guiding protrusion or other guiding structures. In the embodiment of the present invention, the guide part on the coupling base 100 can cooperate with the partition wall of the coaxial cavity filter through a groove structure, and the coupling structure can be conveniently installed in the coaxial cavity filter.

In the embodiment of the coupling structure of the present invention, the first clamping groove 101 can be recessed from the third surface 130 of the coupling base 100, the first clamping groove 101 can penetrate from the first surface 110 and the second surface 120, and the coupling component can be clamped into the third surface 130 of the coupling base 100. In a card slot 101. The second card slot 102 runs through the first surface 110 and the second surface 120, the second card slot 102 can be recessed from the third surface 130 of the coupling base 100, and can also be recessed from the fourth surface 140 of the coupling base 100, wherein The fourth surface 140 is opposite to the third surface 130 . The coupling component can also be detachably snapped into the second slot 102 . In the embodiment of the present invention, the distance h1 from the first slot 101 to the fifth surface 150 of the coupling base 100 is not equal to the distance h2 from the second slot 102 to the fifth surface 150 , and the fifth surface 150 and the first surface 110 are respectively , the intersection of the second surface 120 and the third surface 130 .

In the embodiment of the present invention, the coupling component can be snapped into the first slot 101 or the second slot 102, because the distance h1 from the first slot 101 to the fifth surface 150 is not equal to the distance h1 from the second slot 102 to the second slot. The distance h2 of the fifth surface 150 , that is, snapping the coupling component into the first slot 101 and the second slot 102 , can make the distances between the coupling component and the fifth surface 150 different. Therefore, when the coupling structure is installed in the coaxial cavity filter, the coupling structure can be in different positions in the coaxial cavity filter, so that the coupling structure and the resonator of the coaxial cavity filter can achieve different The amount of coupling increases the versatility of the coaxial cavity filter.

In the embodiment of the present invention, the coupling component may consist of a first coupling flange 211 , a second coupling flange 221 and a coupling rod 230 . In the embodiment of the present invention, the first coupling end 210 can be the first coupling flange 211, the second coupling end 220 can be the second coupling flange 221, and the first coupling flange 211 and the second coupling flange 221 are connected by a coupling rod. 230 is fixed on the coupling base 100, of course, the first coupling end 210 and the second coupling end 220 may also have other structures, not limited to coupling flanges. The coupling rod 230 is detachably snapped into the first slot 101, so in the embodiment of the present invention, when installing the first coupling flange 211 and the second coupling flange 221 on the coupling base 100, only the coupling rod 230 needs to be Inserted into the first card slot 101, the installation process does not require additional fixtures or equipment, which can improve installation efficiency.

In addition, in the embodiment of the present invention, the coupling structure can also be installed on the coaxial cavity filter upside down. As shown in FIG. At different heights, the sixth surface 160 is opposite to the fifth surface 150, the positions of the first coupled end 210 and the second coupled end 220 in the resonant cavity are different, and the amount of coupling between them and the resonator is also different, so the implementation of the present invention For example, four different coupling amounts can be realized when the coupling structure is installed in the forward direction and reverse direction, so as to meet the requirements of the coaxial cavity filter on the coupling amount and reduce the cost.

Referring to FIG. 3 , FIG. 3 is a schematic diagram of a second embodiment of the coupling structure provided by the present invention.

As shown in FIG. 3 , the first card slot 101 in the embodiment of the present invention is recessed from the fifth surface 150 of the coupling base 100 , and the first card slot 101 penetrates from the first surface 110 and the second surface 120 . Wherein, the fifth surface 150 respectively intersects the first surface 110 , the second surface 120 and the third surface 130 , and the coupling component can be snapped into the first slot 101 . The second card slot 102 runs through the first surface 110 and the second surface 120, the second card slot 102 can be recessed from the sixth surface (not shown in FIG. The fifth surface 150 is concave, the sixth surface is opposite to the fifth surface 150 , and the coupling component can be detachably engaged in the second card slot 102 . In the embodiment of the present invention, the depth M1 of the first card slot 101 recessed from the fifth surface 150 is not equal to the depth M2 of the second card slot 102 recessed from the sixth surface. In addition, the second card slot 102 can also be recessed from the fifth surface 150 of the coupling base 100, the depth M1 of the first card slot 101 recessed from the fifth surface 150 is not equal to the second card slot 102 recessed from the fifth surface 150 The depth of M2.

In the embodiment of the present invention, the coupling component can be snapped into the first slot 101 or the second slot 102, because the depth M1 of the first slot 101 recessed from the fifth surface 150 is not equal to the second slot The depth M2 of 102 being recessed from the sixth surface, that is, snapping the coupling component into the first locking groove 101 and the second locking groove 102 , can make the distances from the coupling component to the fifth surface 150 different. Therefore, when the coupling structure is installed in the coaxial cavity filter, the coupling structure can be in different positions in the coaxial cavity filter, so that the coupling structure and the resonator of the coaxial cavity filter can achieve different The amount of coupling increases the versatility of the coaxial cavity filter.

In the embodiment of the present invention, the coupling component can be a metal sheet 260, the first coupling end 210 is the first end 261 of the metal sheet 260, and the second coupling end 220 is the second end 262 of the metal sheet 260, wherein the metal sheet 260 The first end 261 is surrounded by an arc, and the second end 262 of the metal sheet 260 is surrounded by an arc. In the embodiment of the present invention, the first coupling end 210 and the second coupling end 220 are integrally formed, of course, they can also be formed separately. Just maintain electrical contact. In the embodiment of the present invention, the first end 261 of the metal sheet 260 and the second end 262 of the metal sheet 260 can be used to couple with the resonator inside the resonant cavity respectively, by changing the arc shape of the first end 261 of the metal sheet The perimeter or the perimeter of the arc-shaped part of the second end 262 of the metal sheet, or the distance between the first end 261 of the metal sheet or the second end 262 of the metal sheet and the resonator to achieve different coupling amounts, which is different from that in the prior art Compared with using a coupling flange and a resonator for coupling, the coupling structure of the embodiment of the present invention has a wider adjustment range of the coupling amount, which can meet the suppression requirement that is difficult to achieve with the existing capacitive coupling structure.

In addition, the embodiment of the present invention only needs to insert the metal sheet 260 into the first slot 101 or the second slot 102 when installing the metal sheet 260. Compared with the prior art where the coupling flange is screwed into the mounting screw, this In the embodiment of the invention, the metal sheet 260 can be conveniently installed on the coupling base 100 without additional fixtures or equipment for assembly, thereby improving installation efficiency.

In the embodiment of the present invention, the coupling structure can also be reversely installed on the coaxial cavity filter, so that there are two different heights on the sixth surface (not shown in FIG. 3 ) of the metal sheet 260, and the first coupling end 210 The position of the second coupling end 220 in the resonant cavity is different, and the coupling amount between it and the resonator is also different. Therefore, the embodiment of the present invention can realize four different coupling amounts when the coupling structure is installed in the forward direction and reversed. , to meet the coupling requirements of the coaxial cavity filter, to adapt to more application scenarios, thereby reducing costs.

A guiding part may also be provided on the third surface 130 of the embodiment of the present invention, and the guiding part may extend in a direction perpendicular to the first surface 110 or in a direction parallel to the first surface 110 and the second surface 120 , in the embodiment of the present invention, the guide component is a guide groove 131, and the guide groove 131 extends along a direction parallel to the first surface 110 and the second surface 120. Of course, the guide component is not limited to the guide groove, and may also be a guide protrusion or other guiding structures. A guide groove 141 may also be provided on the fourth surface 140 of the embodiment of the present invention, and the guide groove 141 extends along a direction parallel to the first surface 110 and the second surface 120 . In the embodiment of the present invention, the guide part on the coupling base 100 can cooperate with the partition wall of the coaxial cavity filter through a groove structure, and the coupling structure can be conveniently installed on the coaxial cavity filter.

Referring to FIG. 4 , FIG. 4 is a schematic diagram of a first embodiment of a coaxial cavity filter provided by the present invention.

The embodiment of the coaxial cavity filter of the present invention is mainly composed of multiple resonant cavities and coupling structures. The multiple resonant cavities include a first resonant cavity 300 and a second resonant cavity 400, and the first resonator 301 is located in the first resonant cavity 300. Inside, the second resonator 401 is located in the second resonant cavity 400 . The coupling structure in the embodiment of the present invention has been described in detail in the above first embodiment of the coupling structure, and will not be described again here. Wherein, the coupling structure can be detachably installed on the partition wall 305 between the first resonant cavity 300 and the second resonant cavity 400 through a guide component. In the embodiment of the present invention, the guide component is a guide groove 131 (not shown in FIG. 4 shown) and a guide member 141 (not shown in FIG. 4 ), of course the guide member is not limited to a guide groove, and may also be a guide protrusion or other guide structures.

In the embodiment of the present invention, the first coupling end 210 on the coupling component is coupled to the first resonator 301 , and the second coupling end 220 is coupled to the second resonator 401 . In the embodiment of the present invention, the first coupling end 210 may be a first coupling flange 211, the second coupling end 220 may be a second coupling flange 221, and the first coupling flange 211 and the second coupling flange 221 may pass through The coupling rod 230 is fixed on the coupling base 100. Of course, the coupling component is not limited to using a coupling flange, and other structures such as coupling wires can also be used to form the coupling component.

When the coupling structure in the embodiment of the present invention is installed to the coaxial cavity filter, the coupling rod 230 can be installed in the first slot 101 (not shown in FIG. 4 ) and the second slot 102 (in FIG. 4 ). Not shown) to achieve two different amounts of coupling. In addition, in the embodiment of the present invention, the coupling structure can be installed on the coaxial cavity filter along the forward direction or the reverse direction in practical application, and the coupling structure installed in the reverse direction can also realize two different coupling amounts, so as to meet the requirements of the coaxial cavity filter. Requirements for the coupling amount of the cavity filter to achieve different frequency bands and performance index requirements, adapt to more application scenarios, and reduce costs.

Referring to FIG. 5 , FIG. 5 is a schematic diagram of a second embodiment of a coaxial cavity filter provided by the present invention.

The difference between the second embodiment of the coaxial cavity filter of the present invention and the first embodiment of the above-mentioned coaxial cavity filter lies in the coupling structure. The coupling structure in the second embodiment of the coaxial cavity filter of the present invention is the same as the above-mentioned coupling structure The structure of the second embodiment is the same. In the second embodiment of the coaxial cavity filter, the first coupling end 210 is the first end 261 of the metal sheet 260, the first end 261 of the metal sheet 260 forms an arc, and the second coupling end 220 is the metal sheet 260 The second end 262 of the metal sheet 260 is surrounded by an arc. The first end 261 of the metal sheet 260 and the second end 262 of the metal sheet 260 are respectively used to couple with the first resonator 301 and the second resonator 401 inside the resonant cavity. The present invention is implemented by changing the circle of the first end 261 of the metal sheet. The circumference of the arc portion or the circumference of the arc portion of the second end 262 of the metal sheet, or the distance between the first end 261 of the metal sheet or the second end 262 of the metal sheet and the resonator to achieve different coupling amounts, and Compared with the prior art using coupling flanges and resonators for coupling, the coupling structure of the embodiment of the present invention has a wider adjustment range of the coupling amount, which can meet the suppression requirements that are difficult to achieve in the existing coaxial cavity filter .

The coupling structure in the second embodiment of the coaxial cavity filter of the present invention can be detachably installed on the partition wall 305 between the first resonant cavity 300 and the second resonant cavity 400 through guide components, in the embodiment of the present invention The guiding components are guiding grooves 131 (not shown in FIG. 4 ) and guiding grooves 141 (not shown in FIG. 4 ). Of course, the guiding components are not limited to guiding grooves, and can also be guiding protrusions or other guiding structures.

In the embodiment of the present invention, the metal sheet 260 can also be detachably installed inside the first card slot 101 . The distance M1 that the first card slot 101 is recessed from the fifth surface 150 is not equal to the distance M2 that the second card slot 102 is recessed from the sixth surface 160, that is, the metal sheet 260 is inserted inside the first card slot 101 and inserted in the second card slot 101. The inside of the card slot 102 can have two different coupling amounts. In the embodiment of the present invention, the metal sheet 260 can be installed in the corresponding card slot to meet the requirements of the coaxial cavity filter on the coupling amount and adapt to more Many application scenarios, thereby reducing manufacturing costs. In addition, in the embodiment of the present invention, the coupling structure can also be installed on the coaxial cavity filter along different directions. When the coupling structure is installed in reverse, the metal sheet 260 can be installed in different slots, because the first The depths of the card slot 101 and the second card slot 102 are different, so that the distances from the metal sheet 260 to the sixth surface (not shown in FIG. 5 ) of the coupling structure are different, and two different coupling amounts can be realized, satisfying the coaxial Requirements for the coupling amount of the cavity filter, so as to achieve different frequency bands and performance index requirements. In the embodiment of the present invention, different shapes can be designed for the first end 261 of the metal sheet 260 and the second end 262 of the metal sheet 260, so as to realize different coupling amounts and meet the requirements of the coaxial cavity filter on the coupling amount. Adapt to more application scenarios, thereby reducing costs.

It is easy to understand that the coupling structure provided by the embodiment of the present invention is provided with two slots for accommodating coupling components. In other optional embodiments, the coupling components may also be provided with three, four or more slots. The card slot makes the adjustment of the coupling condition between the coupling component and the resonator more flexible.

Furthermore, in the embodiment of the present invention, the slots on the coupling structure are linear structures, and in other optional embodiments, the above slots can be in various shapes, and correspondingly, the shape of the coupling component Corresponding adjustments can also be made, as long as it is ensured that the coupling part is detachably fixedly connected to the coupling base through the slot.

The coupling structure of the present invention and the coaxial cavity filter adopting the coupling structure have been introduced in detail above. For those skilled in the art, the shape of the slot can be designed according to the coupling components inserted into it. The first coupling The shape of the coupling end and the second coupling end can also be designed according to needs. According to the idea of the embodiment of the present invention, there will be changes in the specific implementation and application range. The content of this specification should not be construed as a limitation of the present invention.

Claims (10)

1. A coupling device, comprising: a coupling base, a coupling part installed on the coupling base, the first coupling end of the coupling part protrudes from the first surface of the coupling base, and the coupling part of the coupling part The second coupling end protrudes from the second surface of the coupling base, the first surface is opposite to the second surface, and the coupling base further includes: The first card slot and the second card slot on the coupling base, the first coupling end and the second coupling end are respectively connected to the two ends of a coupling rod, and the coupling rod is stuck in the first card slot or the second card slot In the card slot, the coupling part can be selectively fixedly connected to the coupling base through the first card slot or the second card slot, so that the coupling state of the coupling device can be adjusted according to the position of the coupling part . 2. Coupling device according to claim 1, characterized in that, The coupling base is also provided with a guide member on its third surface, the third surface intersects the first surface and the second surface; The guide member extends in a direction perpendicular to the first surface, or in a direction parallel to the first surface and the second surface, and the guide member is a guide groove. 3. Coupling device according to claim 2, characterized in that, The first card slot is recessed from the third surface of the coupling base; The second card slot is recessed from the third surface or the fourth surface of the coupling base, the fourth surface is opposite to the third surface, and the fourth surface is opposite to the first surface and the second surface intersect. 4. Coupling device according to claim 2, characterized in that, The first card slot is recessed from the fifth surface of the coupling base, and the fifth surface intersects the first surface, the second surface, and the third surface; The second card slot is recessed from the fifth surface or the sixth surface of the coupling base, the sixth surface is opposite to the fifth surface, and the sixth surface is opposite to the first surface and the second surface. Surfaces intersect. 5. Coupling device according to claim 4, characterized in that, The first coupling end of the coupling part is the first end of the metal sheet, the second coupling end of the coupling part is the second end of the metal sheet, and the metal sheet is detachably snapped into the first slot middle. 6. A coaxial cavity filter, comprising a first resonant cavity and a second resonant cavity, the first resonant cavity is adjacent to the second resonant cavity, and a first resonator is included in the first resonant cavity , the second resonant cavity includes a second resonator, It is characterized in that it also includes a coupling device, the coupling device is detachably installed on the partition wall between the first resonant cavity and the second resonant cavity, the first coupling end of the coupling component is connected to the The first resonator is coupled, the second coupling end of the coupling component is coupled to the second resonator, and the coupling device further includes: A coupling base, a coupling component installed on the coupling base, the first coupling end of the coupling component protrudes from the first surface of the coupling base, and the second coupling end of the coupling component extends from the coupling base protruding from a second surface of the first surface opposite to the second surface, The coupling base also includes: a first clamping slot and a second clamping slot located on the coupling base, the first coupling end and the second coupling end are respectively connected to two ends of a coupling rod, and the coupling rod is clamped on In the first card slot or the second card slot, the coupling part can be fixedly connected with the coupling base through the first card slot or the second card slot, so that the coupling part can be adjusted according to the position of the coupling part. The coupling status of the coupling device described above. 7. The coaxial cavity filter according to claim 6, characterized in that, The coupling base is also provided with a guide part on its third surface, the third surface intersects the first surface and the second surface, and the coupling device is detachably mounted on the guide part through the guide part. on the partition wall between the first resonant cavity and the second resonant cavity. 8. The coaxial cavity filter according to claim 7, wherein: The first card slot is recessed from the third surface of the coupling base; The second card slot is recessed from the third surface or the fourth surface of the coupling base, the fourth surface is opposite to the third surface, and the fourth surface is opposite to the first surface and the second surface intersect. 9. The coaxial cavity filter according to claim 7, wherein: The first card slot is recessed from the fifth surface of the coupling base, and the fifth surface intersects the first surface, the second surface, and the third surface; The second card slot is recessed from the fifth surface or the sixth surface of the coupling base, the sixth surface is opposite to the fifth surface, and the sixth surface is opposite to the first surface and the second surface. Surfaces intersect. 10. The coaxial cavity filter according to claim 9, characterized in that, The first coupling end of the coupling part is the first end of the metal sheet, the second coupling end of the coupling part is the second end of the metal sheet, and the metal sheet is detachably snapped into the first slot middle.

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