Phase shifter

Abstract

The embodiment of the utility model provides a phase shifter, which belongs to the technical field of mobile communication and comprises a supporting plate, a phase shifting circuit, a first cover plate, a pull rod and a first fixing piece, the supporting plate is used for supporting; the phase shift circuit comprises a first main substrate and a first sliding block, the first sliding block is rotationally arranged above the first main substrate, the first main substrate is fixed above the supporting plate, and a plurality of convex blocks are arranged on the first side edge of the supporting plate; the first cover plate is located above the first sliding block, and a linkage part is arranged at the lower end of the first cover plate. The pull rod is meshed with the linkage part; the first fixing piece comprises a plurality of limiting grooves and a pull rod guide sleeve, the limiting grooves are matched with the protruding blocks on the first side edge, and the pull rod guide sleeve is matched with one end of the pull rod; wherein the first fixing piece is detachably connected with the first side edge, the occupied space of the phase shifter can be reduced, the assembly error of the pull rod and the phase shifter can be reduced, and the performance of the base station antenna can be improved.

Description

Technical Field

[0001] The present application relates to the field of mobile communication technology, and in particular to a phase shifter. Background Art

[0002] With the development of wireless communication technology, base station electrically-adjustable antennas are widely used. Phase shifters, as one of the key components, can change the feeding phase of the radiating unit in the base station antenna to achieve the shaping and scanning of the radiation beam. The performance of the phase shifter directly affects the performance of the base station antenna, and thus affects the quality of the entire network coverage.

[0003] To adapt to different application scenarios, the operating frequency bands of base station antennas and the number of oscillators they require are different. The resulting problems are that there are more and more phase shifting devices in base station antennas, the feeding network is becoming more and more complex, and the size of the phase shifter is increasing.

[0004] In existing phase shifters, additional pull rod guide sleeves are usually added to the reflector to fix the pull rod, and then the pull rod is used to drive the phase shift circuit on the phase shifter to change the dielectric constant of the phase shift circuit, thereby achieving phase adjustment. When the internal space of the antenna is limited, it will bring difficulties to the layout of the phase shifter, making it difficult to free up enough phase adjustment space and easily increase the assembly error between the pull rod and the phase shifter, thereby affecting the performance of the base station antenna. Utility Model Content

[0005] The purpose of the utility model is to solve at least one of the technical problems existing in the prior art and to provide a phase shifter, which can reduce the space occupied by the phase shifter and reduce the assembly error between the pull rod and the phase shifter, thereby improving the performance of the base station antenna.

[0006] To achieve the above-mentioned purpose, the embodiment of the present application proposes a phase shifter, comprising: a support plate, a phase shifting circuit, a first cover plate, a pull rod, and a first fixing member;

[0007] The support plate is used as a support;

[0008] The phase shift circuit comprises a first main substrate and a first slider, wherein the first slider is rotatably arranged above the first main substrate, the first main substrate is fixed above the support plate, and a first side edge of the support plate is provided with a plurality of protrusions;

[0009] The first cover plate is located above the first sliding block, and a linkage portion is provided at the lower end of the first cover plate;

[0010] The pull rod is meshingly connected with the linkage portion;

[0011] The first fixing member includes a plurality of limiting grooves and a pull rod guide sleeve, wherein the limiting grooves match with the protrusions on the first side, and the pull rod guide sleeve matches with one end of the pull rod;

[0012] Wherein, the first fixing member is detachably connected to the first side.

[0013] A phase shifter provided in accordance with an embodiment of the utility model has at least the following beneficial effects: a support plate is used to support a phase shifting circuit, and a first cover plate is provided above the phase shifting circuit. Furthermore, a linkage portion at the lower end of the first cover plate is meshed and connected with a pull rod, and the linkage portion is driven to rotate by moving the pull rod, and then the first cover plate is moved to drive the first slider located under the first cover plate to slide above the first main substrate, thereby achieving the purpose of changing the phase, wherein one end of the pull rod is supported by a pull rod guide sleeve, and the pull rod guide sleeve is integrally installed with a first fixing member nested on the first side edge of the support plate, which can better fix the position of the phase shifter and the pull rod, reducing assembly errors, and also avoiding the need to additionally set a pull rod guide sleeve on the reflector to support the pull rod, thereby reducing the space occupied by the phase shifter.

[0014] In some embodiments, a first transmission line is disposed on the first main substrate, and a second transmission line matching the first transmission line is disposed above the first slider.

[0015] In some embodiments, the first fixing member further includes a plurality of first wire clamps, and the first wire clamps are used to fix a first cable connected to the first transmission line.

[0016] In some embodiments, a second fixing member is further included, which is detachably connected to the second side of the support plate, and the second fixing member has the same structural size as the first fixing member, and the second side is parallel to the first side and has the same structural size.

[0017] In some embodiments, the first cover plate includes a plurality of elastic arms and a plurality of limit blocks, the bottom of the elastic arms abuts against the surface of the first slider, a plurality of limit holes are provided above the first slider, and the limit holes cooperate with the limit blocks.

[0018] In some embodiments, the third side edge on the support plate is an outwardly convex arc, and a first undercut is provided at the upper end of the first cover plate, and the first undercut abuts against the third side edge and slides along the third side edge.

[0019] In some embodiments, a third fixing member is further included, and the third fixing member is arranged above the first cover plate, the first cover plate is provided with a rotating block, the rotating block extends with a rotating shaft, the first main base plate and the support plate are respectively provided with an axial hole matching with the lower end of the rotating shaft, and the third fixing member is provided with an axial hole matching with the upper end of the rotating shaft.

[0020] In some embodiments, the linkage portion is provided with a first rack, the middle portion of the pull rod is provided with a second rack, and the first rack cooperates with the second rack.

[0021] In some embodiments, a second main substrate is provided below the support plate, a second slider is provided below the second main substrate, a second cover plate is provided below the second slider, and a fourth fixing member is provided above the second cover plate.

[0022] In some embodiments, the third fixing member is provided with a first screw hole, the support plate is provided with a second screw hole matching with the third fixing member, the fourth fixing member is provided with a third screw hole matching with the third fixing member, and rivets are provided between the first screw hole, the second screw hole and the third screw hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the technical solution of the utility model and constitute a part of the specification. Together with the embodiments of the utility model, they are used to explain the technical solution of the utility model and do not constitute a limitation on the technical solution of the utility model.

[0024] The utility model is further described below in conjunction with the accompanying drawings and embodiments;

[0025] Figure 1 is an overall schematic diagram of a phase shifter provided by an embodiment of the utility model;

[0026] Figure 2 is an exploded diagram of a phase shifter provided by an embodiment of the utility model;

[0027] Figure 3 It is a structural schematic diagram of a first fixing member provided in an embodiment of the utility model;

[0028] Figure 4 It is a structural schematic diagram of a support plate provided in an embodiment of the utility model;

[0029] Figure 5 It is a structural schematic diagram of a first sliding block provided in an embodiment of the utility model;

[0030] Figure 6 It is a structural schematic diagram of the first main substrate provided by an embodiment of the utility model;

[0031] Figure 7 It is a structural schematic diagram of a first cover plate provided in an embodiment of the utility model;

[0032] Figure 8 It is a partial enlarged view of the first cover plate provided in the embodiment of the utility model;

[0033] Fig. 9It is a structural schematic diagram of the second cover plate provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0034] This section will describe in detail the specific embodiments of the utility model. The preferred embodiments of the utility model are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the utility model, but it cannot be understood as a limitation on the protection scope of the utility model.

[0035] In the description of the utility model, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0037] The embodiment of the utility model provides a phase shifter, which can reduce the space occupied by the phase shifter and reduce the assembly error between the pull rod and the phase shifter, thereby improving the performance of the base station antenna.

[0038] The following is a further description of the embodiments of the present invention in conjunction with the accompanying drawings.

[0039] Reference Figures 1 to 9 The utility model provides a phase shifter, comprising: a support plate 500, a phase shift circuit, a first cover plate 210, a pull rod 710, and a first fixing member 610;

[0040] The support plate 500 is used as a support;

[0041] The phase shift circuit includes a first main substrate 410 and a first slider 310. The first slider 310 is rotatably disposed above the first main substrate 410. The first main substrate 410 is fixed above the support plate 500. A plurality of protrusions 510 are disposed on the first side of the support plate 500.

[0042] The first cover plate 210 is located above the first slider 310, and a linkage portion 211 is provided at the lower end of the first cover plate 210;

[0043] The pull rod 710 is meshedly connected with the linkage part;

[0044] The first fixing member 610 includes a plurality of limiting grooves 711 and a guide sleeve of the pull rod 710, wherein the limiting groove 711 matches with the protrusion 510 on the first side, and the guide sleeve of the pull rod 710 matches with one end of the pull rod 710;

[0045] The first fixing member 610 is detachably connected to the first side.

[0046] According to a phase shifter provided in an embodiment of the utility model, a support plate 500 is used to support a phase shifting circuit, and a first cover plate 210 is provided above the phase shifting circuit. Furthermore, a linkage portion at the lower end of the first cover plate 210 is meshed and connected with a pull rod 710, and the linkage portion is driven to rotate by moving the pull rod 710, and then the first slider 310 located below the first cover plate 210 is driven to slide above the first main substrate 410 through the movement of the first cover plate 210, thereby achieving the purpose of changing the phase, wherein one end of the pull rod 710 is supported by a pull rod 710 guide sleeve, and the pull rod 710 guide sleeve is integrally installed with a first fixing member 610 nested on the first side of the support plate 500, which can better fix the position of the phase shifter and the pull rod 710, reduce assembly errors, and also avoid the need to additionally set a pull rod 710 guide sleeve on the reflector to support the pull rod 710, thereby reducing the space occupied by the phase shifter.

[0047] It should be noted that the shape of the linkage portion 211 is a fan shape.

[0048] It should be noted that a layer of green oil is applied on the surface of the first main substrate 410 close to the support plate 500. Furthermore, a layer of white insulating material is applied on the basis of the green oil layer, which can well isolate the first main substrate 410 and the support plate 500, and better improve the intermodulation index inside the base station antenna. There is no need to add an additional layer of insulating material with a certain thickness, which reduces the cost, reduces the space occupied by the phase shifter and simplifies the assembly process.

[0049] It should be noted that the guide sleeve of the pull rod 710 is fixed to the end of the first fixing member 610, and the guide sleeve of the pull rod 710 supports the pull rod 710, so that the front end of the pull rod 710 is placed on the fourth side of the support plate 500 and is tightly engaged with the linkage part at the lower end of the first cover plate 210.

[0050] Preferably, the thickness of the first main substrate 410 is 0.8 mm or 1.6 mm, and the thickness of the first slider 310 is 0.8 mm or 1.6 mm.

[0051] When a first main substrate 410 with a thickness of 1.6 mm and a first slider 310 with a thickness of 0.8 mm are used, or a first main substrate 410 with a thickness of 1.6 mm and a first slider 310 with a thickness of 0.8 mm are used, preferably, a support plate 500 with a thickness of 1.2 mm is used.

[0052] It should be noted that when a first slider 310 with a thickness of 0.8 mm and a first main substrate 410 with a thickness of 1.6 mm are used, a support plate 500 with a thickness of 1.2 mm is used; when a first slider 310 with a thickness of 0.8 mm and a first main substrate 410 with a thickness of 0.8 mm are used, a support plate 500 with a thickness of 2 mm is used.

[0053] It can be understood that by adopting the first main substrate 410, the first slide 310, and the support plate 500 of different thicknesses, the overall thickness of the three after being matched can be kept at the same value. Only the same first cover plate needs to be used, and there is no need to replace different types of first cover plates. It has strong versatility and reduces production costs.

[0054] Reference Figure 5 , Figure 6 In some embodiments, a first transmission line 411 is disposed on the first main substrate 410 , and a second transmission line 311 cooperating with the first transmission line 411 is disposed above the first slider 310 .

[0055] It should be noted that the structure of the first transmission line 411 can be: two first horizontal connecting lines 10 on the same horizontal line on both sides, and a convex arc-shaped slow-wave microstrip transmission line 20 in the middle, and the two ends of the slow-wave microstrip transmission line are respectively connected to the ends of the two first horizontal connecting lines 10 close to the middle position.

[0056] Specifically, the slow-wave microstrip transmission line 20 includes a plurality of slow-wave structures, and two adjacent slow-wave structures are arranged in opposite directions to each other.

[0057] It can be understood that when the number of ports of the phase shifter is large, the transmission line using a slow-wave structure can further reduce the size.

[0058] Reference Figure 3 In some embodiments, the first fixing member 610 further includes a plurality of first wire clamps 713 , and the first wire clamps 713 are used to fix the first cable connected to the first transmission line 411 .

[0059] Preferably, there can be 7 first wire clamps 713, and the number of first wire clamps 713 can be appropriately adjusted within the range of 5-10. Since there are more first wire clamps on the first fixing member, in actual use, it can adapt to most first main substrates with different numbers of ports, has strong versatility, and reduces production costs.

[0060] It should be noted that in order to adapt to different application scenarios, the operating frequency bands of base station antennas and the number of oscillators they require are different, and the corresponding phase shifters will also operate in different frequency bands and have different numbers of ports on the first main substrate on the phase shifter.

[0061] Furthermore, there can be 3 to 11 ports above the first main substrate 410. Since a large number of first wire clamps 713 are reserved, they can adapt to first main substrates 410 with different numbers of ports. There is no need to replace different first fixing members 610 to adapt to first main substrates 410 with different numbers of ports, and the versatility is strong.

[0062] Reference Figure 1 , Figure 2 , Figure 3 In some embodiments, a second fixing member 620 is further included, and the second fixing member 620 is detachably connected to the second side edge on the support plate 500, and the second fixing member 620 has the same structural size as the first fixing member 610, and the second side edge is parallel to the first side edge and has the same structural size.

[0063] It should be noted that a plurality of protrusions 510 are provided on the second side of the support plate 500, and the second fixing member 620 also includes a plurality of limiting grooves 711, a pull rod 710 guide sleeve and a first wire clamp 713, the limiting grooves 711 cooperate with the protrusions 510 on the second side, and the pull rod 710 guide sleeve cooperates with the other end of the pull rod 710.

[0064] It can be understood that the other end of the pull rod 710 is supported by the guide sleeve of the pull rod 710 of the second fixing member 620. The second fixing member 620 has the same structural size as the first fixing member 610. It is only necessary to produce the same type of first fixing member 610, and there is no need to install other fixing members to support the other end of the pull rod 710. The assembly is simple and convenient for maintenance and replacement.

[0065] Reference Figure 7 In some embodiments, the first cover plate 210 includes a plurality of elastic arms 212 and a plurality of limit blocks 213 , the bottom of the elastic arms 212 abuts against the surface of the first slider 310 , and a plurality of limit holes 312 are provided above the first slider 310 , and the limit holes 312 cooperate with the limit blocks 213 .

[0066] It should be noted that by arranging a plurality of elastic arms 212 on the first cover plate 210 and the bottom of the elastic arms 212 abutting against the surface of the first slider 310, it can be ensured that when the first cover plate 210 rotates, the surface above the first slider 310 in contact with the first cover plate 210 is subjected to uniform force.

[0067] Furthermore, a plurality of limit blocks 213 are added below the first cover plate 210. The limit blocks 213 cooperate with a plurality of limit holes 312 provided above the first slider 310, and are only used for limiting without fastening. This ensures that the first slider 310 will not deviate from the bottom of the first cover plate 210 during rotation, ensures that the first slider 310 is always subjected to uniform force, thereby improving the accuracy and performance of the phase shifter and improving the working stability of the phase shifter.

[0068] Reference Figure 7 In some embodiments, the third side edge on the support plate 500 is an outwardly convex arc, and a first undercut 214 is provided at the upper end of the first cover plate 210, and the first undercut 214 abuts against the third side edge and slides along the third side edge.

[0069] Reference Figure 8 In some embodiments, a third fixing member 110 is further included. The third fixing member 110 is arranged above the first cover plate 210. The first cover plate 210 is provided with a rotating block, and the rotating block extends with a rotating shaft 216. The first main substrate 410 and the support plate 500 are respectively provided with axial holes matching with the lower end of the rotating shaft 216, and the third fixing member 110 is provided with an axial hole matching with the upper end of the rotating shaft 216.

[0070] It should be noted that by setting an undercut at the upper end of the first cover plate 210 and setting a third fixing member 110 above the first cover plate 210, the first cover plate 210 can be fixed above the phase shifting circuit and moved in a specific direction. By fixing the first cover plate 210, the elastic arm 212 located above the first cover plate 210 can be deformed, and the bottom of the elastic arm 212 can abut against the surface of the first slider 310, so that the first slider 310 is subjected to uniform force.

[0071] It should be noted that by arranging the rotating shaft 216, the first undercut 214 and the linkage part 211 on the first cover plate 210, the first cover plate 210 can be stably moved under the drive of the pull rod 710, so that the first slider 310 fixed under the first cover plate 210 also moves to achieve phase change.

[0072] Reference Figure 1 In some embodiments, the linkage portion 211 is provided with a first rack 211 , and a second rack 720 is provided in the middle of the pull rod 710 , and the first rack 211 cooperates with the second rack 720 .

[0073] It can be understood that, on the one hand, the cooperation of the rack can make the connection between the pull rod 710 and the first cover plate 210 more stable and less likely to loosen or fall off, thereby improving the working accuracy and performance of the phase shifter; on the other hand, the cooperation of the rack can facilitate the movement and adjustment of the pull rod 710, making the operation of changing the phase simpler and more convenient, which is conducive to improving the phase shifting efficiency.

[0074] Reference Figure 1 , Figure 2 In some embodiments, a second main substrate 420 is provided below the support plate 500 , a second slider 320 is provided below the second main substrate 420 , a second cover plate 220 is provided below the second slider 320 , and a fourth fixing member 120 is provided above the second cover plate 220 .

[0075] It should be noted that the second main substrate 420 has the same structural size as the first main substrate 410 , the second slider 320 has the same structural size as the first slider 310 , and the fourth fixing member 120 has the same structural size as the third fixing member 110 .

[0076] Preferably, the thickness of the second main substrate 420 is 0.8 mm or 1.6 mm, and the thickness of the second slider 320 is 0.8 mm or 1.6 mm.

[0077] It should be noted that when the second slider 320 with a thickness of 0.8 mm and the second main substrate 420 with a thickness of 1.6 mm, a support plate 500 with a thickness of 1.2 mm is used; when the second slider 320 with a thickness of 0.8 mm and the second main substrate 420 with a thickness of 0.8 mm, a support plate 500 with a thickness of 2 mm is used.

[0078] It can be understood that by adopting the second main substrate 420, the second slide 320, and the support plate 500 of different thicknesses, the overall thickness of the three can be kept at the same value after being matched. Only the same second cover plate needs to be used, and there is no need to replace different types of second cover plates. It has strong versatility and reduces production costs.

[0079] It should be noted that two first undercuts 214 are disposed at the upper end of the first cover plate 210 , and the two first undercuts 214 abut against the third side and slide along the third side.

[0080] Furthermore, after the two first undercuts 214 disposed on the upper end of the first cover plate 210 abut against the third side, a gap that can just accommodate one undercut is left between the two first undercuts 214 .

[0081] It should be noted that a second undercut 221 is provided at the upper end of the second cover plate 220 , and the second undercut 221 abuts against the third side and slides along the third side.

[0082] Furthermore, a second inverted buckle 221 located at the upper end of the second cover plate 220 is just accommodated in the gap between the two first inverted buckles 214 at the upper end of the first cover plate 210. When the pull rod 710 drives the linkage part 211 of the first cover plate 210 to rotate, the two first inverted buckles 214 at the upper end of the first cover plate 210 will slide along the third side, thereby driving the second inverted buckle 221 on the second cover plate 220 located between the two first inverted buckles 214 set at the upper end of the first cover plate 210 to move.

[0083] Furthermore, driven by the second cover plate 220 , the second slider 320 located below the second cover plate 220 slides above the second main substrate 420 to achieve phase change.

[0084] Reference Figure 1 , Figure 2 , Figure 5 , Figure 6 In some embodiments, the third fixing member 110 is provided with a first screw hole 112, the support plate 500 is provided with a second screw hole 530 matching with the third fixing member 110, the fourth fixing member 120 is provided with a third screw hole 121 matching with the third fixing member 110, and a rivet 111 is provided between the first screw hole 112, the second screw hole 530 and the third screw hole 121.

[0085] It should be noted that by passing the rivet 111 through the first screw hole 112, the second screw hole 530 and the third screw hole 121, the components above the phase shifter can be better pressed, thereby improving the stability of the assembly of components at each layer of the phase shifter and improving the accuracy and performance of the phase shifter.

[0086] It should be noted that the third fixing member 110 is extended with an elastic clip, a first through hole is penetrated through the first main substrate 410, a second through hole is penetrated through the support plate 500, and a third through hole is penetrated through the second main substrate 420, and the elastic clip passes through the first through hole, the second through hole and the third through hole in sequence.

[0087] It should be noted that the provision of the elastic clamp can further better compress the device above the phase shifter to prevent the device from shaking up and down during movement, which is beneficial to improving the accuracy and performance of the phase shifter.

[0088] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A phase shifter, characterized in that: include: A support plate, the support plate being used as a support; A phase shift circuit, the phase shift circuit comprising a first main substrate and a first slider, the first slider is rotatably arranged above the first main substrate, the first main substrate is fixed above the support plate, and a first side edge of the support plate is provided with a plurality of protrusions; A first cover plate, wherein the first cover plate is located above the first sliding block, and a linkage portion is provided at a lower end of the first cover plate; A pull rod, the pull rod is meshedly connected with the linkage portion; A first fixing member, the first fixing member includes a plurality of limiting grooves and a pull rod guide sleeve, the limiting grooves cooperate with the protrusions on the first side, and the pull rod guide sleeve cooperates with one end of the pull rod; Wherein, the first fixing member is detachably connected to the first side.

2. The phase shifter according to claim 1, characterized in that: A first transmission line is disposed on the first main substrate, and a second transmission line matching the first transmission line is disposed above the first sliding block.

3. The phase shifter according to claim 2, characterized in that: The first fixing member further includes a plurality of first wire clamps, and the first wire clamps are used to fix a first cable connected to the first transmission line.

4. The phase shifter according to claim 3, characterized in that: It also includes a second fixing member, which is detachably connected to the second side of the support plate, and the second fixing member has the same structural size as the first fixing member, and the second side is parallel to the first side and has the same structural size.

5. The phase shifter according to claim 1, characterized in that: The first cover plate includes a plurality of elastic arms and a plurality of limiting blocks. The bottom of the elastic arm abuts against the surface of the first sliding block. A plurality of limiting holes are provided above the first sliding block, and the limiting holes cooperate with the limiting blocks.

6. The phase shifter according to claim 1, characterized in that The third side edge on the support plate is in an outwardly convex arc shape, and a first undercut is provided on the upper end of the first cover plate. The first undercut abuts against the third side edge and slides along the third side edge.

7. The phase shifter according to claim 1, characterized in that It also includes a third fixing member, which is arranged above the first cover plate, the first cover plate is provided with a rotating block, the rotating block extends with a rotating shaft, the first main base plate and the support plate are respectively provided with an axial hole matching with the lower end of the rotating shaft, and the third fixing member is provided with an axial hole matching with the upper end of the rotating shaft.

8. The phase shifter according to claim 1, characterized in that The linkage part is provided with a first rack, the middle part of the pull rod is provided with a second rack, and the first rack matches with the second rack.

9. The phase shifter according to claim 7, characterized in that: A second main base plate is disposed below the support plate, a second sliding block is disposed below the second main base plate, a second cover plate is disposed below the second sliding block, and a fourth fixing member is disposed above the second cover plate.

10. The phase shifter according to claim 9, characterized in that The third fixing member is provided with a first screw hole, the support plate is provided with a second screw hole matched with the third fixing member, the fourth fixing member is provided with a third screw hole matched with the third fixing member, and rivets are provided between the first screw hole, the second screw hole and the third screw hole.

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