Dustproof film capacitor

Abstract

The invention discloses a dustproof film capacitor, and relates to the technical field of capacitors. The thin-film capacitor comprises a thin-film capacitor body, the top of the thin-film capacitor body is provided with an installation block, the top of the thin-film capacitor body is provided with a plurality of live wire screwed joints penetrating through the top of the installation block, and the top of the thin-film capacitor body is movably connected with a dustproof protection cover. The two opposite outer sides of the dustproof protection cover are each provided with a plurality of movable cavities corresponding to the multiple live wire threaded connectors. A shielding plate is in sliding fit with the interior of the movable cavity, an extension plate is elastically matched with the bottom of the shielding plate, two opening and closing plates are rotationally matched with the interior of the movable cavity, and connecting assemblies are arranged between the shielding plate and the two opening and closing plates. According to the dustproof protection cover for the live wire screwed joint, through the arrangement of the shielding plate, the extension plate and the two opening and closing plates, the shielding plate, the extension plate and the two opening and closing plates can be combined to shield the movable cavity, so that the situation that dust enters the dustproof protection cover from the movable cavity is reduced, and dust prevention is conducted on the live wire screwed joint.

Description

Technical Field

[0001] The invention belongs to the technical field of capacitors, and in particular relates to a dustproof film capacitor. Background Art

[0002] Film capacitors use metal foil as electrodes, overlap it with plastic films such as polyethylene, polypropylene, polystyrene or polycarbonate at both ends, and then roll it into a cylindrical structure. When film capacitors are installed in parallel, the connection ports on the top are usually protected.

[0003] A Chinese patent with application number CN202223564941.7 discloses a double-sided metallized film capacitor, including a double-sided metallized film capacitor body: the top of the double-sided metallized film capacitor body is fixedly connected to a mounting block by bolts, and three live wire threaded joints are arranged on the top of the double-sided metallized film capacitor body, and the live wire threaded joints pass through the mounting block and extend to the outside of the mounting block. Although the device provides dust protection for the wiring points on the top of the double-sided metallized film capacitor body by fixing the dustproof protective cover to the top of the mounting block, in actual use, there are multiple wiring points on the mounting block, and usually not all of them are wired and used, and the active cavities corresponding to the wiring points that are not used for wiring will be vacant, and dust may enter the dustproof protective cover from the vacant active cavity, affecting multiple wiring points.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a dust-proof film capacitor.

[0006] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: A dustproof film capacitor comprises a film capacitor body, a mounting block is arranged on the top of the film capacitor body, a plurality of live wire threaded joints penetrating the top of the mounting block are arranged on the top of the film capacitor body, a dustproof protective cover is movably connected to the top of the film capacitor body, the mounting block is located in the dustproof protective cover, and a plurality of movable cavities corresponding to the plurality of live wire threaded joints are opened on both opposite outer sides of the dustproof protective cover; A shielding plate is slidably matched in the movable cavity, an extension plate is elastically matched at the bottom of the shielding plate, two opening and closing plates are rotatably matched in the movable cavity, a connecting component is arranged between the shielding plate and the two opening and closing plates, and a clamping component is arranged between the mounting block and the dust protection cover.

[0007] Optionally, two receiving grooves are provided at the bottom of the film capacitor body, a rotating plate is rotatably fitted in the receiving groove, and a plurality of mounting holes are provided on the rotating plate.

[0008] Optionally, a live wire connector is sleeved on the circumferential side of the live wire threaded joint, a nut is matched with the circumferential thread of the live wire threaded joint, and a ground wire connecting column is arranged on the top of the film capacitor body.

[0009] Optionally, grooves are provided on both sides of the mounting block, and fixed blocks are provided on both sides of the inner wall of the dust protection cover. The snap-fit ​​assembly includes a snap block that slides in the groove and a slot provided on one side of the fixed block. One side of the snap block is elastically fitted with one side of the groove, and the snap-fit ​​block is snap-fitted with the slot.

[0010] Optionally, the card slot includes a movable slot provided on one side of the fixed block, a sliding cavity provided in the fixed block and connected to the movable slot, the card block is slidably matched with the movable slot, and the card block is snap-fitted with the sliding cavity.

[0011] Optionally, a limiting groove is provided at the bottom of the film capacitor body, a limiting block is provided on one side of the dust protection cover, a handle is installed on the top of the limiting block, a slider is installed on one side of the limiting block, a slide groove is provided on one side of the dust protection cover, and the slider slides in the slide groove.

[0012] Optionally, a pull rod is installed on the top of the baffle plate, and a pull block is installed on one end of the pull rod that passes through the top of the dustproof protective cover, so that the top of the baffle plate is elastically matched with the top of the movable cavity.

[0013] Optionally, a groove is provided at the bottom of the shielding plate, the top of the extension plate is elastically matched with the top of the groove, an arc groove is provided at the bottom of the extension plate, a shielding ring is provided in the arc groove, an opening is provided at the bottom of the shielding ring, and a baffle is provided in the shielding ring.

[0014] Optionally, the connecting assembly includes a first connecting rod rotatably engaged with the top of one of the opening and closing plates, and a second connecting rod rotatably engaged with the top of the other opening and closing plate, and the ends of the first connecting rod and the second connecting rod away from the closing plate are both rotatably connected to the bottom of the shielding plate.

[0015] Optionally, the dustproof protective cover includes a shell and a dustproof net, the dustproof net is arranged in the shell, a plurality of support blocks are installed on the inner wall of the shell, fixing holes are opened on the support blocks, and a plurality of fixing bolts corresponding to the plurality of support blocks are arranged on the dustproof net.

[0016] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time: By means of the provided shielding plate, extension plate and two opening and closing plates, the shielding plate, extension plate and two opening and closing plates can be combined to shield the active cavity, thereby reducing the situation where dust enters the dustproof protective cover from the active cavity, and the live wire threaded joint is dustproof. By means of the provided connecting assembly, the two opening and closing plates can be pushed to rotate, so that the opening and closing plates mobilize the connecting assembly to drive the shielding plate to move upward, so that the connecting wire enters the active cavity, and then the shielding plate will drive the two opening and closing plates to rotate and close through the connecting assembly, and the extension plate pops up from the bottom of the shielding plate to better fit the connecting wire, thereby fixing the connecting wire and playing a dust-proof role at the same time. By means of the provided clamping assembly, when the dustproof protective cover covers the mounting block to protect multiple live wire threaded joints, the mounting block and the dustproof protective cover are clamped through the clamping assembly, so that the dustproof protective cover is fixedly installed on the main body of the film capacitor, which is convenient for installing the dustproof protective cover.

[0017] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described below are only some embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings: Figure 1 This is a schematic diagram of the structure of a dust-proof film capacitor; Figure 2 is a schematic diagram of the rotating plate structure; Figure 3 This is a schematic diagram of the installation block structure; Figure 4 It is a schematic diagram of the structure of the card connection component; Figure 5 is a schematic diagram of the connection component structure; Figure 6 is a schematic diagram of the shielding plate structure; Figure 7 It is a schematic diagram of the structure of the dust protection cover; In the accompanying drawings, the components represented by the reference numerals are listed as follows: The film capacitor body 1, the mounting block 2, the live wire threaded joint 3, the dust protection cover 4, the movable cavity 5, the shielding plate 6, the extension plate 7, the opening and closing plate 8, the connecting assembly 9, the first connecting rod 901, the second connecting rod 902, the card block 10, the card slot 11, the movable slot 1101, the sliding cavity 1102, the storage slot 12, the rotating plate 13, the mounting hole 14, the live wire connector 15, the nut 16, the ground wire connecting column 17, the limit slot 18, the limit block 19, the slider 20, the slide slot 21, the channel 22, the fixed block 23, the pull rod 24, the groove 25, the arc groove 26, the shielding ring 27, the baffle 28, the shell 29, the dust net 30, the support block 31, and the fixing bolt 32.

[0019] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0020] The present invention will now be described in further detail with reference to the accompanying drawings.

[0021] See also Figure 1-7 As shown, in this embodiment, a dust-proof film capacitor is provided, including a film capacitor body 1, a mounting block 2 is installed on the top of the film capacitor body 1, a plurality of live wire threaded joints 3 penetrating the top of the mounting block 2 are arranged on the top of the film capacitor body 1, a dust-proof protective cover 4 is movably connected to the top of the film capacitor body 1, the mounting block 2 is located in the dust-proof protective cover 4, and a plurality of movable cavities 5 corresponding to the plurality of live wire threaded joints 3 are opened on both sides of the dust-proof protective cover 4; A baffle plate 6 is slidably fitted in the movable cavity 5, an extension plate 7 is elastically fitted at the bottom of the baffle plate 6, two opening and closing plates 8 are rotatably fitted in the movable cavity 5, a connecting component 9 is provided between the baffle plate 6 and the two opening and closing plates 8, and a snap-on component is provided between the mounting block 2 and the dustproof protective cover 4.

[0022] The application of one aspect of this embodiment is as follows: when in use, the dustproof protective cover 4 is installed on the film capacitor body 1, and the dustproof protective cover 4 is connected to the mounting block 2 through the clamping assembly, so that the dustproof protective cover 4 covers the mounting block 2 to protect multiple live wire threaded joints 3, and the connecting wire can be connected to the live wire threaded joint 3 through the movable cavity 5. The connecting wire rotates into the movable cavity 5 by squeezing the two opening and closing plates 8. The rotation of the two opening and closing plates 8 will mobilize the connecting assembly 9, so that the connecting assembly 9 drives the shielding plate 6 to move upward, and the shielding plate 6 moves upward to drive the extension plate 7 to move upward. After the connecting line completely enters the active cavity 5, the connecting line does not squeeze the two opening and closing plates 8 at this time, and the shielding plate 6 will move downward to mobilize the connecting component 9, so that the connecting component 9 drives the two opening and closing plates 8 to close, limiting the position of the connecting line while shielding the active cavity 5, and then the extension plate 7 pops out from the bottom of the shielding plate 6, and the extension plate 7 fits with the connecting line while shielding the active cavity 5. While completing the connection of the connecting line, the active cavity 5 can also be shielded. The active cavity 5 without a connecting line will be shielded by the combination of the shielding plate 6, the extension plate 7 and the two opening and closing plates 8.

[0023] By means of the provided shielding plate 6, extension plate 7 and two opening and closing plates 8, the shielding plate 6, extension plate 7 and two opening and closing plates 8 can be combined to shield the active cavity 5, thereby reducing the situation where dust enters the dustproof protective cover 4 from the active cavity 5, and the live wire threaded joint 3 is dust-proof. By means of the provided connecting component 9, the two opening and closing plates 8 can be pushed to rotate, so that the opening and closing plates 8 mobilize the connecting component 9 to drive the shielding plate 6 to move upward, so that the connecting wire enters the active cavity 5, and then the shielding plate 6 will drive the two opening and closing plates 8 to rotate and close through the connecting component 9, and the extension plate 7 pops up from the bottom of the shielding plate 6 to better fit the connecting wire, fixes the connecting wire and plays a dust-proof role at the same time. By means of the provided clamping component, when the dustproof protective cover 4 covers the mounting block 2 to protect multiple live wire threaded joints 3, the mounting block 2 and the dustproof protective cover 4 are clamped through the clamping component, so that the dustproof protective cover 4 is fixedly installed on the film capacitor body 1, which is convenient for the installation of the dustproof protective cover 4.

[0024] like Figure 2 As shown, the bottom of the film capacitor body 1 of this embodiment is provided with two receiving grooves 12, and a rotating plate 13 is rotatably matched in the receiving groove 12, and a plurality of mounting holes 14 are provided on the rotating plate 13. Through the provided rotating plate 13, the rotating plate 13 can be rotated out of the receiving groove 12, so that the rotating plate 13 can be installed and fixed through the mounting holes 14, and the bolts are fixed to the power distribution cabinet through the mounting holes 14, so that the rotating plate 13 is connected to the power distribution cabinet, and the installation and fixation of the film capacitor body 1 is completed. When not in use, the rotating plate 13 can be rotated and stored in the receiving groove 12.

[0025] like Figure 3 As shown, the live wire threaded joint 3 of this embodiment is sleeved with a live wire connector 15, the live wire threaded joint 3 is threadedly matched with a nut 16, and the top of the film capacitor body 1 is provided with a ground wire connection column 17. Through the provided nut 16, after the connecting wire passes through the live wire connector 15, the nut 16 is rotated to thread the live wire threaded joint 3, so that the nut 16 moves to fix the live wire connector 15 and the connecting wire, and the connection between the connecting wire and the live wire threaded joint 3 is completed.

[0026] Among them, an active cavity 5 corresponding to the ground wire connecting column 17 is opened on one side of the dustproof protective cover 4, and a shielding plate 6, an extension plate 7 and two opening and closing plates 8 are also arranged in the active cavity 5 to protect the ground wire connecting column 17. When in use, the ground wire connecting wire is fixed by the shielding plate 6, the extension plate 7 and the two opening and closing plates 8 in the same way as the live wire threaded joint 3, while shielding the active cavity 5.

[0027] like Figure 3-4As shown, the mounting block 2 of this embodiment is provided with grooves 22 on both sides thereof, and fixing blocks 23 are provided on both sides thereof on the inner wall of the dust protection cover 4. The snap-fit ​​assembly includes a snap-fit ​​block 10 which is slidably fitted in the groove 22, and a snap-fit ​​groove 11 which is provided on one side of the fixing block 23. One side of the snap-fit ​​block 10 is elastically fitted with one side of the groove 22, and the snap-fit ​​block 10 is snap-fitted with the snap-fit ​​groove 11. Through the provided card block 10, when installing the dust protection cover 4, the card slot 11 is aligned with the card block 10, and pressing the dust protection cover 4 can make the card slot 11 squeeze the card block 10, so that the card block 10 slides along the groove 22, and the groove 22 can enter the card slot 11 more easily after moving. The dust protection cover 4 is continuously pressed to make it fit with the top of the film capacitor body 1. At this time, the card block 10 completely enters the card slot 11, and the elastic force will drive the card block 10 to reset and engage with the card slot 11, so that the dust protection cover 4 is connected to the mounting block 2, and the dust protection cover 4 is installed on the top of the film capacitor body 1 to protect the mounting block 2 connection and multiple live wire threaded joints 3.

[0028] like Figure 3-4 As shown, the card slot 11 of this embodiment includes a movable slot 1101 provided on one side of the fixed block 23, a sliding cavity 1102 provided in the fixed block 23 and connected to the movable slot 1101, the card block 10 is slidably matched with the movable slot 1101, and the card block 10 is snap-fitted with the sliding cavity 1102, wherein the movable slot 1101 and the sliding cavity 1102 are connected and combined into an L shape, so that the sliding cavity 1102 can snap-fit ​​with the card block 10. Through the provision of the movable slot 1101, the card block 10 will move along the movable slot 1101, and the card block 10 will move along the movable slot 1101 and enter the sliding cavity 1102, and the card block 10 will enter the sliding cavity 1102 by elastic force for snap-fitting.

[0029] like Figure 3-4 As shown, the bottom of the film capacitor body 1 of this embodiment is provided with a limiting groove 18, a limiting block 19 is provided on one side of the dust protection cover 4, a handle is provided on the top of the limiting block 19, a slider 20 is provided on one side of the limiting block 19, and a slide groove 21 is provided on one side of the dust protection cover 4, and the slider 20 is slidably fitted in the slide groove 21. Through the provided limiting groove 18, after the dust protection cover 4 is aligned with the limiting groove 18, the clamping assembly between the dust protection cover 4 and the mounting block 2 can be clamped more smoothly, so that the dust protection cover 4 is interference-fitted into the limiting groove 18 through the limiting block 19, and the handle is pulled to drive the limiting block 19, so that the limiting block 19 drives the slider 20 to move along the slide groove 21, so that the limiting block 19 moves upward, and after the limiting block 19 moves, the dust protection cover 4 will move in the limiting groove 18, which can push the dust protection cover 4 to move left and right, and release the clamping assembly from fixing the dust protection cover 4.

[0030] like Figure 5As shown, the top of the shielding plate 6 of this embodiment is equipped with a pull rod 24, and one end of the pull rod 24 that passes through the top of the dust protection cover 4 is equipped with a pull block, and the top of the shielding plate 6 is elastically matched with the top of the active cavity 5. Through the set pull rod 24, the pull block is pulled to drive the pull rod 24 to move upward, so that the pull block drives the shielding plate 6 to move upward, and the shielding plate 6 will move along the active cavity 5. The upward movement of the shielding plate 6 will mobilize the connecting component 9, so that the connecting component 9 mobilizes the two opening and closing plates 8 to rotate and open, and one of the shielding plates 6 can be pulled alone to move, so as to release the shielding plate 6, the extension plate 7 and the two opening and closing plates 8 from blocking the active cavity 5, and then the connecting line passes through the active cavity 5 and is connected to the live wire threaded joint 3. After loosening the pull rod 24, the shielding plate 6 will move downward and reset by elastic force, so that the shielding plate 6 mobilizes the connecting component 9, so that the connecting component 9 drives the two opening and closing plates 8 to rotate and close, and the extension plate 7 will fix the connecting line, so that the shielding plate 6, the extension plate 7 and the two opening and closing plates 8 block the active cavity 5.

[0031] like Figure 5 As shown, the connection assembly 9 of this embodiment includes a first connection rod 901 rotatably engaged with the top of one of the opening and closing plates 8, and a second connection rod 902 rotatably engaged with the top of the other opening and closing plate 8. The ends of the first connection rod 901 and the second connection rod 902 away from the closing plate 8 are both rotatably connected to the bottom of the shielding plate 6. The two opening and closing plates 8 are squeezed and rotated by the connecting line to push the first connection rod 901 and the second connection rod 902 respectively. The first connection rod 901 and the second connection rod 902 will push the shielding plate 6 to move upward. When the two opening and closing plates 8 are rotated to open, the shielding plate 6 is moved upward. When the shielding plate 6 moves downward, it pushes the first connection rod 901 and the second connection rod 902, so that the first connection rod 901 and the second connection rod 902 push the two opening and closing plates 8 to rotate and close, so that the shielding plate 6 and the two opening and closing plates 8 can be linked through the connection assembly 9.

[0032] like Figure 6 As shown, the bottom of the shielding plate 6 of this embodiment is provided with a groove 25, the top of the extension plate 7 is elastically matched with the top of the groove 25, the bottom of the extension plate 7 is provided with an arc groove 26, a shielding ring 27 is provided in the arc groove 26, the bottom of the shielding ring 27 is provided with an opening, and a blocking bar 28 is provided in the shielding ring 27. Through the provided shielding ring 27, when the extension plate 7 pops out from the groove 25 and fits with the connecting wire, the connecting wire can enter the shielding ring 27 from the opening, so that the shielding ring 27 fits with the connecting wire, and the arc groove 26 can adapt to the curvature of the connecting wire. When there is no connecting wire in the active cavity 5, the extension plate 7 extends out of the groove 25 to the maximum extent through elastic force, and the blocking bar 28 will shield the shielding ring 27.

[0033] like Figure 7As shown, the dustproof protective cover 4 of this embodiment includes a shell 29 and a dustproof net 30. The dustproof net 30 is arranged in the shell 29. A plurality of support blocks 31 are installed on the inner wall of the shell 29. The support blocks 31 are provided with fixing holes. The dustproof net 30 is provided with a plurality of fixing bolts 32 corresponding to the plurality of support blocks 31. Through the dustproof net 30, the dustproof net 30 can be installed in the shell 29 so that the dustproof net 30 can be ventilated and dustproof. The dustproof net 30 is supported by the plurality of support blocks 31. The fixing bolts 32 pass through the dustproof net 30 and are connected to the corresponding support blocks 31 to fix the dustproof net 30. After long-term use, the dustproof net 30 can be removed for cleaning.

[0034] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A dust-proof film capacitor, characterized in that: include: A film capacitor body (1), a mounting block (2) is mounted on the top of the film capacitor body (1), a plurality of live wire threaded joints (3) are arranged on the top of the film capacitor body (1) and penetrate the top of the mounting block (2), a dustproof protective cover (4) is movably connected to the top of the film capacitor body (1), the mounting block (2) is located inside the dustproof protective cover (4), and a plurality of movable cavities (5) corresponding to the plurality of live wire threaded joints (3) are provided on both sides of the dustproof protective cover (4); A shielding plate (6) is slidably engaged in the movable cavity (5), an extension plate (7) is elastically engaged at the bottom of the shielding plate (6), two opening and closing plates (8) are rotatably engaged in the movable cavity (5), a connecting component (9) is provided between the shielding plate (6) and the two opening and closing plates (8), and a clamping component is provided between the mounting block (2) and the dust protection cover (4).

2. The dust-proof film capacitor according to claim 1, characterized in that: Two receiving grooves (12) are arranged at the bottom of the film capacitor body (1), a rotating plate (13) is rotatably fitted in the receiving groove (12), and a plurality of mounting holes (14) are provided on the rotating plate (13).

3. The dust-proof film capacitor according to claim 1, characterized in that: A live wire connector (15) is sleeved on the circumferential side of the live wire threaded joint (3), a nut (16) is matched with the circumferential thread of the live wire threaded joint (3), and a ground wire connection column (17) is arranged on the top of the film capacitor body (1).

4. The dust-proof film capacitor according to claim 1, characterized in that: The mounting block (2) is provided with grooves (22) on two opposite outer sides, and the inner wall of the dust protection cover (4) is provided with fixing blocks (23) on two opposite sides. The clamping assembly comprises a clamping block (10) slidably fitted in the groove (22), and a clamping groove (11) provided on one side of the fixing block (23). One side of the clamping block (10) is elastically fitted with one side of the groove (22), and the clamping block (10) is clamped and fitted with the clamping groove (11).

5. The dust-proof film capacitor according to claim 4, characterized in that: The clamping slot (11) comprises a movable slot (1101) provided on one side of the fixed block (23), a sliding cavity (1102) provided in the fixed block (23) and connected to the movable slot (1101), the clamping block (10) and the movable slot (1101) are slidably matched, and the clamping block (10) and the sliding cavity (1102) are clamped and matched.

6. The dust-proof film capacitor according to claim 1, characterized in that: A limiting groove (18) is provided at the bottom of the film capacitor body (1), a limiting block (19) is provided on one side of the dust protection cover (4), a handle is provided on the top of the limiting block (19), a sliding block (20) is provided on one side of the limiting block (19), a sliding groove (21) is provided on one side of the dust protection cover (4), and the sliding block (20) is slidably fitted in the sliding groove (21).

7. The dust-proof film capacitor according to claim 1, characterized in that: A pull rod (24) is installed at the top of the baffle plate (6), and a pull block is installed at one end of the pull rod (24) that passes through the top of the dust protection cover (4). The top of the baffle plate (6) is elastically matched with the top of the movable cavity (5).

8. The dust-proof film capacitor according to claim 1, characterized in that: A groove (25) is provided at the bottom of the shielding plate (6), the top of the extension plate (7) is elastically matched with the top of the groove (25), an arc-shaped groove (26) is provided at the bottom of the extension plate (7), a shielding ring (27) is provided in the arc-shaped groove (26), an opening is provided at the bottom of the shielding ring (27), and a blocking bar (28) is provided in the shielding ring (27).

9. The dust-proof film capacitor according to claim 1, characterized in that: The connecting assembly (9) comprises a first connecting rod (901) rotatably engaged with the top of one of the opening and closing plates (8), and a second connecting rod (902) rotatably engaged with the top of the other opening and closing plate (8), wherein the ends of the first connecting rod (901) and the second connecting rod (902) away from the opening and closing plate (8) are both rotatably connected to the bottom of the shielding plate (6).

10. The dust-proof film capacitor according to claim 1, characterized in that: The dustproof protective cover (4) comprises a shell (29) and a dustproof net (30), the dustproof net (30) being arranged in the shell (29), a plurality of support blocks (31) being arranged on the circumference of the inner wall of the shell (29), the support blocks (31) being provided with fixing holes, and a plurality of fixing bolts (32) corresponding to the plurality of support blocks (31) being arranged on the dustproof net (30).

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