Super isolated dry-type transformer

Abstract

This invention relates to the field of transformer technology, specifically to a super-isolated dry-type transformer, comprising a transformer base. Clamping members are symmetrically fixed on both sides of the upper end of the transformer base. Moving grooves are symmetrically formed at both ends of the clamping members, and positioning and mounting holes are symmetrically formed on the transformer base between the clamping members. Matching downward-moving holes are symmetrically formed at both ends of the transformer base. The primary and secondary windings on the iron core are placed in two shielding boxes respectively. The shielding boxes pass through the iron core, which is equivalent to the windings being wound around the iron core. Thus, under the action of the shielding boxes, the primary and secondary windings can be effectively isolated and shielded, achieving a good noise cancellation effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transformer, in particular to a super isolation dry-type transformer. BACKGROUND

[0002] Dry-type transformer is widely used in local lighting, high-rise buildings, airports, wharfs and CNC mechanical equipment, simply speaking, dry-type transformer refers to the transformer whose core and winding are not immersed in insulating oil.

[0003] During the working process of the dry-type transformer, some electromagnetic clutter will be generated, which will cause industrial pollution and seriously affect some precision instruments. The electromagnetic clutter is generated by space electromagnetic wave and stray magnetic field emitted by the transformer itself. In order to isolate the interference of the clutter to the system and equipment, an isolation transformer must be used. However, the ordinary isolation transformer can only achieve basic electrical isolation between the primary and secondary windings, and the effect of eliminating the clutter is not ideal. SUMMARY

[0004] The present application aims to provide a super isolation dry-type transformer to solve the problems in the background art.

[0005] To achieve the above object, the present application provides the following technical scheme:

[0006] A super isolation dry-type transformer comprises a transformer base, the upper end of the transformer base is symmetrically provided with clamping pieces on both sides, the two ends of the clamping pieces are symmetrically provided with moving grooves, the transformer base between the clamping pieces is symmetrically provided with positioning installation holes, the two ends of the transformer base are symmetrically provided with matching lower moving holes, the one side of the transformer base is symmetrically provided with fixed bearing plate pieces at both ends, the fixed bearing plate pieces are provided with plug-in matching holes, the other side of the transformer base is fixedly provided with a U-shaped bearing frame, the two ends of the U-shaped bearing frame are symmetrically provided with matching plug-in grooves and positioning matching grooves, the positioning matching grooves are provided with communication plug-in holes, the side of the U-shaped bearing frame away from the clamping pieces is fixedly provided with a bearing plate block, the bearing plate block is provided with an installation through hole, the transformer base is fixedly provided with an outer shell, the two ends of the outer shell are symmetrically fixedly provided with heat dissipation fins, the two sides of the outer shell are symmetrically fixedly provided with primary and secondary lead boxes, in addition, the upper end of the outer shell is fixedly provided with a cover top, the two ends of the cover top are symmetrically fixedly provided with lifting rings, and the transformer base is provided with a convenient installation and dismounting type core winding shielding mechanism.

[0007] Preferably, the convenient installation and removal type core winding shielding mechanism includes a lower core, an insulating bracket, a movable bracket, a first return spring, a movable positioning strip, a 90-degree bending plate, a movable positioning plate frame, a second return spring, and a shielding box. The lower core consists of two symmetrically installed on the transformer base, and a positioning plug is fixedly provided at the lower end of the lower core. The positioning plug is inserted into the positioning mounting hole.

[0008] Preferably, a core fixing groove is provided on the lower side of one end of the lower core, and a guide rod is fixedly provided on the upper side of one end of the lower core. Two upper cores are symmetrically fixed on the insulating bracket, and a guide insertion hole is provided on the lower side of one end of the upper core, into which a guide rod is inserted.

[0009] Preferably, the insulating bracket has symmetrically fixed downward push plates at both ends, and a protruding plate is fixedly provided on one side of the downward push plate. The protruding plate has a fixed insertion groove, and a pushing slope is provided on the protruding plate below the fixed insertion groove.

[0010] Preferably, the movable brackets are symmetrically installed at both ends of the transformer base, and a matching downward moving rod is fixedly provided at the lower end of the movable bracket. The matching downward moving rod is inserted into the matching downward moving hole, and a first return spring is sleeved on the matching downward moving rod. The two ends of the movable bracket are symmetrically hinged with first push-pull connecting rods, and a movable positioning strip is hinged at the lower end of the first push-pull connecting rod near the clamp.

[0011] Preferably, movable mating blocks are symmetrically fixed on both sides of the movable positioning strip, the movable mating blocks are inserted into the movable groove, and a protruding positioning plate is fixed on the movable positioning strip. When the protruding positioning plate plays a fixing role for the lower iron core, it is inserted into the iron core fixing groove.

[0012] Preferably, a 90-degree bending plate is hinged to the lower end of the first push-pull connecting rod on the movable support away from the clamping member. A protruding connecting block is fixedly provided at one end of the 90-degree bending plate. The protruding connecting block is hinged to the first push-pull connecting rod on the movable support away from the clamping member. A vertical driving plate is fixedly provided at the other end of the 90-degree bending plate. The vertical driving plate is located inside the U-shaped support frame.

[0013] Preferably, a fixed connecting side plate is fixedly provided on one side of the vertical driving plate, and an insertion positioning rod is fixedly provided on the vertical driving plate. The insertion positioning rod is inserted into the connecting hole. In addition, an elastic reset plate is welded on the vertical driving plate, and the other end of the elastic reset plate is welded to the inner end face of the U-shaped support frame.

[0014] Preferably, a second push-pull connecting rod is hinged to the fixed connecting side plate, and a movable connecting plate is hinged to the upper end of the second push-pull connecting rod. A movable locking rod is fixedly provided on the movable connecting plate and is inserted into the mounting through hole.

[0015] Preferably, the movable positioning plate frame has symmetrically fixed support plug rods at both ends, which are inserted into the plug fitting holes. An arc-shaped locking block is fixed at one end of the support plug rod away from the movable positioning plate frame. When the arc-shaped locking block fixes the insulating support, it is inserted into the fixed plug groove. A second return spring is sleeved on the support plug rod. Two shielding boxes are stacked together, and the shielding boxes pass through the lower and upper iron cores. Positioning fitting blocks are symmetrically fixed at both ends of one side of the shielding box, and fixed connection holes are provided on the positioning fitting blocks. The shielding box is covered with a shielding box cover. Protruding fixing plates are symmetrically fixed at both ends of one side of the shielding box cover, and cover fixing holes are provided on the protruding fixing plates.

[0016] Compared with the prior art, the beneficial effects of the present invention are: the present invention has a reasonable structural design and strong functionality, and has the following advantages:

[0017] 1. Place the primary and secondary windings on the iron core in two separate shielding boxes, and pass the shielding boxes through the iron core. This is equivalent to the windings being wound around the iron core. In this way, the shielding boxes can effectively isolate and shield the primary and secondary windings, thus achieving a good noise cancellation effect.

[0018] 2. The core is divided into two parts: a lower core and an upper core. During transformer assembly, the lower and upper cores are combined to form a complete core. The split design of the core facilitates the insertion of the shielding box containing the windings into the core. When assembling the lower and upper cores, pushing the upper core downwards will cause the movable positioning plate to move under the action of the pushing inclined surface. Then, under the action of the second return spring, the arc-shaped locking block will be inserted into the fixed insertion slot, realizing the automatic connection and fixation of the upper and lower cores. The downward movement of the upper core will also push the movable bracket downwards, and under the action of the movable bracket, the protruding positioning plate will be inserted into the core fixing slot, realizing the fixed connection between the lower core and the transformer base, thus realizing the fixed installation of the entire core.

[0019] 3. In addition, as the movable bracket moves downward, it will drive the 90-degree bending plate to move. As the 90-degree bending plate moves, it will drive the insertion positioning rod to be inserted into the fixed connection hole, thereby fixing the shielding box. At the same time, under the action of the 90-degree bending plate, it will drive the movable connecting plate to move upward, thereby allowing the movable locking rod to be inserted into the cover fixing hole, thereby fixing the shielding box cover. This achieves multiple benefits, making the installation and removal of the core and shielding box very convenient, and facilitating maintenance work such as inspection and replacement. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the assembly of a dry-type transformer.

[0021] Figure 2 A first-person view of the assembly inside the outer casing.

[0022] Figure 3 A second-view diagram of the assembly inside the outer casing.

[0023] Figure 4 for Figure 2 Enlarged diagram of point A in the middle.

[0024] Figure 5 for Figure 3 Enlarged diagram of point B in the middle.

[0025] Figure 6 This is a schematic diagram of the transformer base.

[0026] Figure 7 This is a schematic diagram showing the fit between the lower and upper iron cores.

[0027] Figure 8 This is a schematic diagram of a 90-degree bent plate.

[0028] Figure 9 This is a schematic diagram of two shielding boxes stacked together.

[0029] In the diagram: 1. Transformer base; 11. Clamp; 12. Moving groove; 13. Positioning mounting hole; 14. Lowering hole; 15. Fixed bearing plate; 16. Insertion mating hole; 17. U-shaped bearing frame; 171. Mating slot; 18. Positioning mating groove; 181. Connecting insertion hole; 19. Bearing plate; 191. Mounting through hole; 2. Outer shell; 21. Heat sink; 22. Primary and secondary lead box; 3. Top cover; 31. Lifting ring; 4. Lower core; 41. Positioning insertion block; 42. Core fixing groove; 43. Guide mating rod; 5. Insulating bracket; 51. Upper core; 52. Guide insertion hole; 53. Drooping push plate; 54. Protruding plate; 55. Fixed insertion groove; 56. Pushing slope; 6. Movable 61. Bracket; 62. Lowering rod; 63. First return spring; 64. First push-pull linkage; 65. Movable positioning bar; 66. Movable mating block; 67. Protruding positioning plate; 68. Ninety-degree bending plate; 69. Protruding connecting block; 60. Vertical driving plate; 691. Fixed connecting side plate; 692. Insertion positioning rod; 693. Elastic return piece; 694. Second push-pull linkage; 695. Movable connecting plate; 696. Movable locking rod; 7. Movable positioning plate frame; 71. Supporting insertion rod; 72. Arc-shaped locking block; 73. Second return spring; 8. Shielding box; 81. Positioning mating block; 82. Fixed connection hole; 83. Shielding box cover; 84. Protruding fixing plate; 85. Cover fixing hole. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figures 1 to 9 The present invention provides a technical solution:

[0032] A super-isolated dry-type transformer includes a transformer base 1. Clamping members 11 are symmetrically fixed on both sides of the upper end of the transformer base 1. Moving grooves 12 are symmetrically formed at both ends of the clamping members 11. Positioning mounting holes 13 are symmetrically formed on the transformer base 1 between the clamping members 11. Matching downward moving holes 14 are symmetrically formed at both ends of the transformer base 1. Fixed bearing plates 15 are symmetrically fixed on both ends of one side of the transformer base 1, and insertion mating holes 16 are formed on the fixed bearing plates 15. A U-shaped bearing frame 17 is fixedly fixed on the other side of the transformer base 1. Matching holes 16 are symmetrically formed at both ends of the U-shaped bearing frame 17. The transformer base 1 has a slot 171 and a positioning groove 18. The positioning groove 18 has a connecting insertion hole 181. A bearing plate 19 is fixedly installed on the side of the U-shaped support frame 17 away from the clamp 11. The bearing plate 19 has a mounting through hole 191. The transformer base 1 has a housing 2 fixedly installed. Heat sinks 21 are symmetrically fixedly installed at both ends of the housing 2. Primary and secondary lead boxes 22 are symmetrically fixedly installed on both sides of the housing 2. In addition, a cover 3 is fixedly installed at the top of the housing 2. Lifting rings 31 are symmetrically fixedly installed at both ends of the cover 3. A convenient installation and removal iron core winding shielding mechanism is installed on the transformer base 1.

[0033] The convenient installation and removal type iron core winding shielding mechanism includes a lower iron core 4, an insulating bracket 5, a movable bracket 6, a first return spring 62, a movable positioning strip 64, a 90-degree bending plate 67, a movable positioning plate frame 7, a second return spring 73, and a shielding box 8. The lower iron core 4 consists of two symmetrically installed on the transformer base 1, and a positioning plug-in block 41 is fixedly provided at the lower end of the lower iron core 4. The positioning plug-in block 41 is inserted into the positioning mounting hole 13, and the size of the positioning plug-in block 41 is equal to the size of the positioning mounting hole 13.

[0034] A core fixing groove 42 is provided on the lower side of one end of the lower core 4, and a guide rod 43 is fixedly provided on the upper side of one end of the lower core 4. Two upper cores 51 are symmetrically fixedly installed on the insulating bracket 5. A guide insertion hole 52 is provided on the lower side of one end of the upper core 51, and a guide rod 43 is inserted into the guide insertion hole 52. After the lower core 4 and the upper core 51 are installed, they are closed together to form a complete core.

[0035] The insulating bracket 5 has symmetrically fixed downward push plates 53 at both ends. A protruding plate 54 is fixedly installed on one side of the downward push plate 53. A fixed insertion groove 55 is provided on the protruding plate 54. A pushing slope 56 is provided on the protruding plate 54 below the fixed insertion groove 55. The surface of the pushing slope 56 is smooth and burr-free.

[0036] The movable bracket 6 is symmetrically installed at both ends of the transformer base 1, and a matching downward moving rod 61 is fixedly provided at the lower end of the movable bracket 6. The matching downward moving rod 61 is inserted into the matching downward moving hole 14, and a first return spring 62 is sleeved on the matching downward moving rod 61. The two ends of the movable bracket 6 are symmetrically hinged with a first push-pull connecting rod 63, and the lower end of the first push-pull connecting rod 63 near the clamp 11 is hinged with a movable positioning strip 64. The two ends of the first return spring 62 are respectively welded to the movable bracket 6 and the transformer base 1.

[0037] The movable positioning bar 64 is symmetrically fixed with movable mating blocks 65 on both sides. The movable mating blocks 65 are inserted into the movable groove 12. The movable positioning bar 64 is fixed with a protruding positioning plate 66. When the protruding positioning plate 66 plays a role in fixing the lower iron core 4, it is inserted into the iron core fixing groove 42.

[0038] The lower end of the first push-pull connecting rod 63 on the movable bracket 6, away from the clamp 11, is hinged to a 90-degree bending plate 67. One end of the 90-degree bending plate 67 is fixedly provided with a protruding connecting block 68, which is hinged to the first push-pull connecting rod 63 on the movable bracket 6, away from the clamp 11. The other end of the 90-degree bending plate 67 is fixedly provided with a vertical driving plate 69, which is located inside the U-shaped support frame 17.

[0039] A fixed connecting side plate 691 is fixedly installed on one side of the vertical drive plate 69, and a plug-in positioning rod 692 is fixedly installed on the vertical drive plate 69. The plug-in positioning rod 692 is inserted into the connecting hole 181. In addition, an elastic reset piece 693 is welded on the vertical drive plate 69, and the other end of the elastic reset piece 693 is welded to the inner end face of the U-shaped support frame 17.

[0040] A second push-pull connecting rod 694 is hinged to the fixed connecting side plate 691. A movable connecting plate 695 is hinged to the upper end of the second push-pull connecting rod 694. A movable locking rod 696 is fixedly installed on the movable connecting plate 695 and is inserted into the mounting through hole 191.

[0041] Preferably, the movable positioning plate frame 7 has symmetrically fixed support plug rods 71 ​​at both ends. The support plug rods 71 ​​are inserted into the plug fitting holes 16, and an arc-shaped locking block 72 is fixedly installed at the end of the support plug rod 71 away from the movable positioning plate frame 7. When the arc-shaped locking block 72 plays a role in fixing the insulating bracket 5, it is inserted into the fixed plug groove 55. A second return spring 73 is sleeved on the support plug rod 71. The two ends of the second return spring 73 are respectively welded to the arc-shaped locking block 72 and the fixed bearing plate 15. There are two shielding boxes 8, which are stacked together. The lower shielding box 8 is supported on the clamp 11, and the shielding box 8 passes through the lower iron core 4 and the upper iron core 51. A positioning and mating plug 81 is symmetrically fixed at both ends of the shielding box 8. The positioning and mating plug 81 has a fixed connection hole 82 and is inserted into the positioning and mating groove 18. The shielding box 8 is covered with a shielding box cover 83. A protruding fixing plate 84 is symmetrically fixed at both ends of one side of the shielding box cover 83. The protruding fixing plate 84 has a cover fixing hole 85 and is inserted into the mating slot 171. In addition, after the shielding box 8 is installed, the connecting plug 181 is aligned with the fixed connection hole 82, and the mounting through hole 191 is aligned with the cover fixing hole 85. In addition, the secondary winding is placed in the lower shielding box 8, and the primary winding is placed in the upper shielding box 8.

[0042] During the installation of the core and shielding box 8, the positioning plug 41 at the lower end of the lower core 4 is inserted into the positioning mounting hole 13 to position the lower core 4. Then, the two shielding boxes 8 are stacked and placed through the lower core 4, so that one side of them contacts the U-shaped support frame 17, and the outer surfaces of both ends contact the inner end face of the lower core 4 near the movable bracket 6. At this time, the shielding box 8 is positioned. Then, the upper core 51 is sleeved on the guide fitting rod 43 and moved downward so that the lower end of the drooping push plate 53... The upper core 51 moves downwards, causing the upper core 51 to move downwards, which in turn causes the lower core 4 to move downwards. This, in turn, causes the upper core 51 to move downwards, and the lower core 4 to move in opposite directions, driven by the first push-pull linkage 63. The protruding positioning plate 66 on the upper core 51 then inserts into the core fixing slot 42 to fix the lower core 4. Simultaneously, the movement of the 90-degree bending plate 67 causes the vertical driving plate 69 to move, thus allowing the positioning rod 692 to be inserted. The shielding box 8 is fixed by inserting it into the fixed connection hole 82. Additionally, as the vertical drive plate 69 moves, the second push-pull connecting rod 694 pushes the movable connecting plate 695 upwards, causing the movable locking rod 696 to move upwards and insert into the cover fixing hole 85. This fixes the shielding box 8 and the shielding box cover 83. Meanwhile, as the downward push plate 53 moves downwards, the push-up inclined surface 56 pushes the arc-shaped locking block 72 until it engages with the fixed... The fixed insertion slots 55 are aligned, and then the arc-shaped locking block 72 is inserted into the fixed insertion slots 55 under the action of the second return spring 73, thereby fixing the upper iron core 51. At this time, the upper iron core 51 and the lower iron core 4 are closed together, achieving multiple benefits at the same time. The lower iron core 4, the upper iron core 51, the shielding box 8 and the shielding box cover 83 can be fixed simultaneously. The operation is simple, convenient and quick. When disassembly is required, simply pull the movable positioning plate frame 7 to make the arc-shaped locking block 72 exit the fixed insertion slots 55.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A super-isolated dry-type transformer, comprising a transformer base (1), characterized in that: The transformer base (1) is symmetrically fixed with clamps (11) on both sides of its upper end. The clamps (11) have symmetrically opened moving grooves (12) at both ends. The transformer base (1) between the clamps (11) has symmetrically opened positioning mounting holes (13). The transformer base (1) has symmetrically opened mating downward moving holes (14) at both ends. The transformer base (1) has symmetrically fixed with fixed bearing plates (15) at both ends on one side. The fixed bearing plates (15) have inserted mating holes (16). The transformer base (1) has a U-shaped bearing frame (17) fixed on the other side. The U-shaped bearing frame (17) has symmetrically opened mating slots at both ends. (171) and positioning groove (18), the positioning groove (18) is provided with a connecting insertion hole (181), and a bearing plate (19) is fixedly provided on the side of the U-shaped bearing frame (17) away from the clamp (11), the bearing plate (19) is provided with a mounting through hole (191), the transformer base (1) is fixedly installed with a shell (2), the two ends of the shell (2) are symmetrically fixedly installed with heat sinks (21), and the two sides of the shell (2) are symmetrically fixedly installed with primary and secondary lead boxes (22). In addition, the upper end of the shell (2) is fixedly installed with a cover (3), and the two ends of the cover (3) are symmetrically fixedly installed with lifting rings (31). A convenient installation and removal type core winding shielding mechanism is installed on the transformer base (1). The convenient installation and removal type core winding shielding mechanism includes a lower core (4), an insulating bracket (5), a movable bracket (6), a first reset spring (62), a movable positioning strip (64), a 90-degree bending plate (67), a movable positioning plate frame (7), a second reset spring (73), and a shielding box (8). There are two lower cores (4), which are symmetrically installed on the transformer base (1). The lower end of the lower core (4) is fixedly provided with a positioning plug-in block (41). The positioning plug-in block (41) is inserted into the positioning mounting hole (13). A core fixing is opened on the lower side of one end of the lower core (4). The groove (42) and the upper side of one end of the lower iron core (4) are fixedly provided with a guide mating rod (43). Two upper iron cores (51) are symmetrically fixedly installed on the insulating bracket (5). A guide insertion hole (52) is opened on the lower side of one end of the upper iron core (51). A guide mating rod (43) is inserted into the guide insertion hole (52). A drooping push plate (53) is symmetrically fixedly provided at both ends of the insulating bracket (5). A protruding plate (54) is fixedly provided on one side of the drooping push plate (53). A fixed insertion groove (55) is opened on the protruding plate (54) on the lower side of the fixed insertion groove (55). A push-up slope (56) is provided on the protruding plate (54).

2. The super-isolation dry-type transformer according to claim 1, characterized in that: The movable bracket (6) is symmetrically installed at both ends of the transformer base (1), and a matching downward moving rod (61) is fixedly provided at the lower end of the movable bracket (6). The matching downward moving rod (61) is inserted into the matching downward moving hole (14), and a first return spring (62) is sleeved on the matching downward moving rod (61). The two ends of the movable bracket (6) are symmetrically hinged with a first push-pull connecting rod (63), and a movable positioning strip (64) is hinged at the lower end of the first push-pull connecting rod (63) near the clamp (11).

3. A super-isolation dry-type transformer according to claim 2, characterized in that: The movable positioning bar (64) is symmetrically fixed with movable mating blocks (65) on both sides. The movable mating blocks (65) are inserted into the movable groove (12). The movable positioning bar (64) is fixed with a protruding positioning plate (66). When the protruding positioning plate (66) plays a fixing role for the lower iron core (4), it is inserted into the iron core fixing groove (42).

4. A super-isolation dry-type transformer according to claim 3, characterized in that: The lower end of the first push-pull connecting rod (63) on the movable bracket (6) away from the clamp (11) is hinged with a 90-degree bending plate (67). One end of the 90-degree bending plate (67) is fixedly provided with a protruding connecting block (68). The protruding connecting block (68) is hinged to the first push-pull connecting rod (63) on the movable bracket (6) away from the clamp (11). The other end of the 90-degree bending plate (67) is fixedly provided with a vertical driving plate (69). The vertical driving plate (69) is located inside the U-shaped support frame (17).

5. A super-isolation dry-type transformer according to claim 4, characterized in that: A fixed connecting side plate (691) is fixedly provided on one side of the vertical drive plate (69), and a plug-in positioning rod (692) is fixedly provided on the vertical drive plate (69). The plug-in positioning rod (692) is inserted into the connecting hole (181). In addition, an elastic reset piece (693) is welded on the vertical drive plate (69), and the other end of the elastic reset piece (693) is welded to the inner end face of the U-shaped support frame (17).

6. A super-isolation dry-type transformer according to claim 5, characterized in that: A second push-pull link (694) is hinged to the fixed connection side plate (691). A movable connecting plate (695) is hinged to the upper end of the second push-pull link (694). A movable locking rod (696) is fixedly provided on the movable connecting plate (695). The movable locking rod (696) is inserted into the mounting through hole (191).

7. A super-isolation dry-type transformer according to claim 6, characterized in that: The movable positioning plate frame (7) is symmetrically fixed with support plug rods (71) at both ends. The support plug rods (71) are inserted into the plug fitting holes (16), and an arc-shaped locking block (72) is fixedly provided at one end of the support plug rod (71) away from the movable positioning plate frame (7). When the arc-shaped locking block (72) plays a role in fixing the insulating bracket (5), it is inserted into the fixed plug groove (55). A second return spring (73) is sleeved on the support plug rod (71). The shielding box ( 8) There are two, stacked together, and the shielding box (8) passes through the lower iron core (4) and the upper iron core (51). The two ends of one side of the shielding box (8) are symmetrically fixed with positioning and mating blocks (81). The positioning and mating blocks (81) are provided with fixed connection holes (82). The shielding box (8) is covered with a shielding box cover (83). The two ends of one side of the shielding box cover (83) are symmetrically fixed with protruding fixing plates (84). The protruding fixing plates (84) are provided with cover fixing holes (85).

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