Built-in current transformer

Abstract

The present application belongs to the technical field of current transformers. Disclosed is a built-in current transformer. The built-in current transformer comprises an upper support insulator, a housing, a lower support insulator, a support cylinder, a plurality of coils, an engaging tooth assembly, racks, a sliding piece and an elastic structure, wherein the housing comprises a radial contraction section, and a vertical gap between the inner wall of the radial contraction section and an upper port of the support cylinder is a shielding gap; the plurality of coils are sleeved on the outer side of the support cylinder in sequence in an axial direction; the engaging tooth assembly comprises a plurality of first triangular teeth, and the first triangular teeth are fixedly connected to the outer wall of the support cylinder; the racks are parallel to the axis of the support cylinder, each rack has a plurality of second triangular teeth, the upper end of each rack abuts against the lower surface of the sliding piece; and the elastic force of the elastic structure is configured to force the racks to move downwards so as to change a state in which inclined surfaces of the second triangular teeth are completely fitted against inclined surfaces of the first triangular teeth to a state in which the inclined surfaces of the second triangular teeth are partially fitted against the inclined surfaces of the first triangular teeth. The present application can improve the mounting stability and convenience of the coils.

Description

An embedded current transformer Technical Field

[0001] This application belongs to the field of current transformer technology and relates to a built-in current transformer. Background Technology

[0002] As an important component of GIS, the main function of current transformer is to convert the large primary current in the system into a small current according to a specified ratio, isolate the large current in the primary circuit, and provide current for various instruments and relay protection in the secondary system. It is an important electrical device in the power system.

[0003] Existing built-in current transformers form an airtight cavity inside the casing, with an inner support cylinder inside the airtight cavity. The coil is then fitted onto the outside of the inner support cylinder. The existing structure is referenced in Chinese Patent No. CN213546101U, which uses epoxy resin casting to fix the coil to the outside of the inner support cylinder. Although this method can improve the installation stability of the coil, it requires the use of tooling to apply a large axial pressure to the coil to ensure that the gap between the coils is extremely small in order to reduce the overflow of the high-pressure epoxy resin. As a result, the coil is easily damaged by pressure, especially the coil with a core, and this method is also relatively cumbersome.

[0004] Secondly, the background technology of Chinese patent CN213546101U also provides a fixing method, which is to use a tightening bolt to hold the pressure plate, and the pressure plate applies axial pressure to each coil to complete the fixing. This method is more convenient than epoxy resin casting, and the axial pressure applied is smaller, which causes less damage to the coil. However, this fixing method only limits the coil axially. During transportation or when subjected to vibration, the coil may move circumferentially and radially, and the bolt may also loosen, that is, the stability of the coil is poor. Summary of the Invention

[0005] To address the challenge of balancing ease of coil mounting with stability, a built-in current transformer is provided.

[0006] This application provides a built-in current transformer, which is implemented using the following technical solution:

[0007] An embedded current transformer includes an upper supporting insulator, a housing, a lower supporting insulator, a supporting cylinder, multiple coils, a mating gear assembly, a rack, a sliding plate, and an elastic structure. The supporting cylinder is coaxially arranged with the housing. A flange is integrally formed on the lower outer wall of the supporting cylinder. An annular resin gasket is provided on the upper surface of the flange. The flange is fixedly connected to the lower end of the housing by a first bolt. The lower end of the housing has a threaded hole that mates with the first bolt. The bolt head presses against the lower surface of the flange. The housing includes a radially contracting section. The vertical gap between the inner wall of the radially contracting section and the upper port of the supporting cylinder is a shielding gap. Multiple coils are sequentially sleeved on the outside of the supporting cylinder along the axial direction. The lowermost coil presses against the resin gasket. The toothed assembly includes multiple first triangular teeth evenly arranged along the axial direction of the support cylinder. The first triangular teeth are fixedly connected to the outer wall of the support cylinder. The rack is parallel to the axis of the support cylinder. The surface of the rack has a first rubber coating. The rack has multiple second triangular teeth. The slide plate is axially slidingly engaged with the support cylinder. The upper end of each rack abuts against the lower surface of the slide plate. The elastic structure is installed on the inner wall of the radial contraction section. The elastic force of the elastic structure is used to force the rack to move downward to change the state in which the second triangular tooth inclined surface and the first triangular tooth inclined surface are completely in contact to the state in which the second triangular tooth inclined surface and the first triangular tooth inclined surface are partially in contact. When the second triangular tooth inclined surface and the first triangular tooth inclined surface are partially in contact, the side wall of the rack abuts against the inner circumferential surface of the coil.

[0008] With the above technical solution, during installation, the rack is installed on the outside of the support cylinder. At this time, the inclined surface of the second triangular tooth is completely in contact with the inclined surface of the first triangular tooth, the radial distance between the rack and the support cylinder is minimized, and the outer diameter of the virtual circle formed by the racks is minimized. The rack is less likely to interfere with the coil, thus facilitating the placement of the coil on the outside of the support cylinder. At this time, there is a radial gap between the rack and the inner diameter of the coil. Then, the slider is placed on the upper end of the support cylinder, ensuring that the lower surface of the slider abuts against the upper end of the rack. Then, the support cylinder is installed inside the housing. By tightening the first bolt, the support cylinder and the coil move upward relative to the housing. As the slider moves upward with the support cylinder, it touches the elastic structure. The elastic structure accumulates elastic potential energy, and the elastic force of the elastic structure is applied downward to the slider. The slider forces the rack to move downward, so as to place the first... The state of complete contact between the second triangular toothed inclined surface and the first triangular toothed inclined surface changes to a state of partial contact between the second triangular toothed inclined surface and the first triangular toothed inclined surface. At the same time, guided by the first triangular toothed inclined surface, the rack moves radially outward along the support cylinder. The outer diameter of the virtual circle formed by the racks is the largest. The sidewalls of the racks abut against the inner circumference of the coils to clamp each coil, thereby limiting the circumferential and radial movement of the coils. Furthermore, since the surface of the racks has a first rubber coating with a high coefficient of friction, the friction force is used to axially limit the coils, thereby greatly improving the installation stability of the coils. Moreover, no additional tooling is required. During the installation of the support cylinder, when the support cylinder moves relative to the shell, the energy stored in the elastic structure is used to complete the fixing of the coils, which is quite convenient.

[0009] Furthermore, during use or transportation, the elastic force of the elastic structure is always applied to the rack. When the coil vibrates radially, the rack has a tendency to displace vertically. The elastic structure will buffer the displacement tendency of the rack, and the vertical displacement of the rack will rub against the coil. The kinetic energy of the vibration is converted into frictional heat energy, thereby achieving the shock absorption effect.

[0010] Optionally, the bevel of the first triangular tooth has a second rubber coating, and the bevel of the second triangular tooth has the first rubber coating.

[0011] Through the above technical solution, when the coil vibrates radially and the second triangular tooth of the rack and the first triangular tooth of the support cylinder are relatively displaced, the relative displacement of the first and second rubber coatings generates heat due to the friction coefficients, which converts the kinetic energy of the vibration into frictional heat energy, thereby achieving the vibration reduction effect.

[0012] Optionally, a strip groove is axially extended through the outer circumferential surface of the support cylinder, and the bottom of the strip groove is integrally formed with the first triangular tooth; the two opposite groove walls of the strip groove have a third rubber coating, and the surface of the first rubber coating of the toothed rack is in contact with the surface of the third rubber coating of the strip groove.

[0013] Through the above technical solution, by setting the cooperation of the strip groove and the rack, the rack can be limited along the circumference of the support cylinder. Furthermore, the first rubber coating surface of the rack is in contact with the third rubber coating surface of the strip groove. Since the first rubber coating and the third rubber coating have a certain coefficient of friction, there is a damping between the first rubber coating and the third rubber coating, so that the rack is not easy to fall out after it is assembled into the strip groove, so that the rack is deeply hidden in the strip groove. The outer diameter of the virtual circle formed by the racks is small, which facilitates the insertion of the coil.

[0014] Optionally, the mating gear assembly further includes a resin sleeve, the outer wall of the support sleeve is provided with a spline, and the inner wall of the resin sleeve is provided with a keyway that mates with the spline; the outer wall of the resin sleeve is axially provided with a strip groove, and the bottom of the strip groove is integrally formed with the first triangular tooth; the two opposite groove walls of the strip groove are provided with a third rubber coating, and the surface of the first rubber coating of the gear rack is in contact with the surface of the third rubber coating of the strip groove.

[0015] Through the above technical solution, the resin sleeve is integrally injection molded, which is relatively simple to manufacture, and the first triangular tooth has high dimensional accuracy, which can improve the displacement accuracy of the rack, thereby improving the fixing accuracy of the coil.

[0016] Optionally, the elastic structure includes a connecting ring and a plurality of first spring pieces. The connecting ring is fixed to the inner wall of the radial contraction section by a second bolt. Each first spring piece is evenly arranged along the circumference of the support cylinder. One end of the first spring piece is integrally formed and connected to the connecting ring, and the other end of the first spring piece is inclined downward and extends toward the axis of the support cylinder. The lower end of the first spring piece elastically presses against the upper surface of the slide plate.

[0017] The above technical solution uses a connecting ring, which is installed on the inner wall of the radial contraction section using a second bolt, to fix multiple first spring pieces to the housing. This is convenient, and the multiple first spring pieces are evenly distributed, which can apply elastic force to the slide plate more evenly, thereby improving the displacement stability of each rack.

[0018] Optionally, the elastic structure includes a connecting ring and multiple second spring pieces. The connecting ring is fixed to the inner wall of the radial contraction section by a second bolt. Each second spring piece is evenly arranged along the circumference of the support cylinder. The second spring pieces, along the direction away from the connecting ring, include a first inclined section, a first U-shaped bendable section, a second inclined section, a first fold-back section, a third inclined section, a second U-shaped bendable section, a fourth inclined section, a second fold-back section, a fifth inclined section, and a third fold-back section connected in sequence. The first and second inclined sections are both inclined downwards, the third and fourth inclined sections are both inclined upwards, and the fifth inclined section is inclined downwards. A protrusion is fixed to the inner wall of the radial contraction section, and the protrusion abuts against the side of the fourth inclined section. Tightening the first bolt drives the support... During the upward movement of the tube and the coil relative to the housing, the upper surface of the slider first abuts against the outer arc surface of the third fold section. The elastic force of the fifth inclined section forces the slider to move downward through the third fold section, changing the state of complete contact between the second triangular tooth inclined surface and the first triangular tooth inclined surface to a state of partial contact between the second triangular tooth inclined surface and the first triangular tooth inclined surface. At this time, the surface of the coil abuts against the outer arc surface of the first fold section again. The first U-shaped bendable section is elastically compressed, and the second and third inclined sections deflect upward. The elastic force of the first U-shaped bendable section forces each coil to be axially pressed through the second inclined section and the first fold section. The upward deflection of the third inclined section will drive the fourth and fifth inclined sections to deflect downward with the protrusion as the fulcrum.

[0019] Through the above technical solution, when the first bolt is tightened, the bolt head abuts against the lower surface of the flange, causing the flange to move upward relative to the housing, thereby causing the support cylinder and coil to move upward relative to the housing. During this process, the upper surface of the slider first abuts against the outer arc surface of the third fold section (at this time, the coil has not yet contacted the first fold section). The elastic force of the fifth inclined section forces the slider to move downward through the third fold section, changing the state of complete contact between the second triangular tooth inclined surface and the first triangular tooth inclined surface to a state of partial contact between the second triangular tooth inclined surface and the first triangular tooth inclined surface. During this state switching process, under the guidance of the first triangular tooth inclined surface, the rack moves radially outward along the support cylinder, thereby limiting the circumferential and radial movement of the coil. As the first bolt is tightened further to drive the support cylinder and coil upward, the fifth inclined section continues to accumulate elastic potential energy, forcing the rack to continue to move radially outward. The outer diameter of the virtual circle formed by the racks is the largest, and the sidewall of the rack abuts against the inner circumferential surface of the coil to clamp each coil, and the clamping force becomes larger and larger, while the surface of the coil begins to abut against the inner circumferential surface of the coil. The outer arc surface of the first folded section, the elastic compression of the first U-shaped bendable section, and the upward deflection of the second and third inclined sections. The elastic force of the first U-shaped bendable section forces each coil to be axially pressed together through the second inclined section and the first folded section, thereby reducing the axial gap between the coils and reducing the occurrence of coil vibration and collision due to the axial gap. At the same time, the upward deflection of the third inclined section will drive the fourth and fifth inclined sections to deflect downward with the protrusion as the fulcrum. The downward deflection of the fifth inclined section further applies downward pressure to the slider and rack through the third folded section, further increasing the clamping force of the rack on the coil, thereby improving the installation stability of the coil. It can be understood that within the limited axial displacement space of the support cylinder and the coil, the elastic deformation triggered by the second spring is limited. However, by increasing the linkage of the second, fourth, and fifth inclined sections and the protrusion, the clamping force of the fifth inclined section on the rack is further increased, thereby greatly improving the installation stability of the coil under limited conditions.

[0020] Optionally, the elastic structure includes a connecting ring, multiple second spring pieces, and a force transmission rod. The connecting ring is fixed to the inner wall of the radial contraction section by a second bolt. The second spring pieces are evenly arranged along the circumference of the support cylinder. The second spring pieces, along the direction away from the connecting ring, include a first inclined section, a first U-shaped bendable section, a second inclined section, a first fold-back section, a third inclined section, a second U-shaped bendable section, a fourth inclined section, a second fold-back section, a fifth inclined section, and a third fold-back section connected in sequence. The first and second inclined sections are both inclined downwards, the third and fourth inclined sections are both inclined upwards, and the fifth inclined section is inclined downwards... The lower section is configured such that a protrusion is fixed to the inner wall of the radial contraction section, and the protrusion abuts against the side of the fourth inclined section; two force transmission rods are respectively located on both sides of the width direction of the second inclined section, one end of the force transmission rod is welded and fixed to the middle of the side of the second inclined section, and the other end of the force transmission rod is fixed with a plurality of unidirectional teeth evenly spaced along its own length direction. The unidirectional teeth are right-angled triangles, and the side of the fifth inclined section is inserted into the unidirectional teeth; a rubber ring is provided at the fitting gap between the lower end of the housing and the flange; during the process of tightening the first bolt to drive the support cylinder and the coil to move upward relative to the housing, the surface of the coil... The first U-shaped bendable section abuts against the outer arc surface of the first fold section, and the second and third inclined sections are elastically compressed. The second inclined section deflects upward, and the upward deflection of the second inclined section drives the force transmission rod to move relative to the fifth inclined section. Each one-way tooth elastically avoids the fifth inclined section in sequence, and the elastic force of the first U-shaped bendable section passes through the second inclined section and the first fold section to force each coil to be axially pressed. Continue to tighten the first bolt to make the support cylinder continue to move upward, and the upper surface of the slide plate abuts against the outer arc surface of the third fold section. The elastic force of the fifth inclined section passes through the third fold section to force the slide plate to move downward, so as to align the inclined surface of the second triangular tooth with the first triangular tooth. The state of complete contact between the toothed bevels changes to a state where the second triangular toothed bevel and the first triangular toothed bevel are partially contacted. At this time, the side wall of the rack abuts against the inner circumference of the coil and the rubber ring is in a fully compressed state. Then, loosen the first bolt, and the support cylinder and the coil move down to a state where the rubber ring is not fully compressed. The first U-shaped bendable section recovers some elastic deformation, and the second inclined section deflects downward. Since the side of the second inclined section is stuck at the coarse end of the one-way tooth, the second inclined section will drive the fifth inclined section to deflect downward together. There is a gap between the outer arc surface of the first fold-back section and the coil, and the third fold-back section maintains the state of elastic contact with the slider.

[0021] Through the above technical solution, when the first bolt is tightened, the bolt head abuts against the lower surface of the flange, causing the flange to move upward relative to the housing, thereby causing the support cylinder and coil to move upward relative to the housing. During this process, the surface of the coil first abuts against the outer arc surface of the first fold section (the upper surface of the slider has not yet contacted the third fold section), the first U-shaped bendable section is elastically compressed, the second and third inclined sections deflect upward, and the upwardly deflected second inclined section causes the force transmission rod to move relative to the fifth inclined section. Each one-way tooth elastically avoids the fifth inclined section in sequence, and the elastic force of the first U-shaped bendable section forces each coil to be axially compressed through the second inclined section and the first fold section, thereby reducing the axial gap between each coil and reducing the occurrence of coil vibration and collision due to the axial gap of the coil. Continue to tighten the first bolt to make the support cylinder continue to move upward until the rubber ring is in a fully compressed state. During this process, the upper surface of the slider abuts against the outer arc surface of the third fold section, and the elastic force of the fifth inclined section forces the slider to move downward through the third fold section, so as to make the inclined surface of the second triangular tooth and the first The state of complete contact between the triangular toothed inclined surfaces changes to a state of partial contact between the second triangular toothed inclined surfaces and the first triangular toothed inclined surfaces. During this state transition, guided by the first triangular toothed inclined surface, the rack moves radially outward along the support cylinder, thereby limiting the circumferential and radial movement of the coil. Then, the first bolt is loosened, and the support cylinder and coil move downward until the rubber ring is in a partially compressed state (the rubber ring is compressed to 30% to 70% of full compression). After the first fold-back section loses the contact of the coil, the first fold-back section has room to move, allowing the second fold-back section to move freely. The first U-shaped bendable section recovers some elastic deformation, and the second inclined section deflects downward. Since the side of the second inclined section is stuck at the coarse end of the one-way tooth, the second inclined section will drive the fifth inclined section to deflect downward together. The downward deflected fifth inclined section further applies downward pressure to the slider and rack through the third folding section, further increasing the rack's clamping force on the coil, thereby improving the coil's installation stability. Finally, there is a gap between the outer arc surface of the first folding section and the coil, meaning the coil is not subjected to axial pressure, thus reducing the occurrence of axial pressure damage to the coil.

[0022] In summary, during the installation process, the second inclined section first applies axial pressure to the coil to compress the gap between the coils. The fifth inclined section then abuts against the slider to complete the outward expansion of the rack. The rack radially clamps the coil. Next, the first bolt is loosened to move the support cylinder and the coil downward to relieve the axial pressure on the coil and reduce coil damage. At the same time, the force transmission rod is used to make the fifth and second inclined sections form a whole, so that the elastic force of the fifth inclined section and the elastic force of the first U-shaped bendable section are superimposed on the rack, further improving the clamping effect. This can be understood as follows: within the limited axial displacement space of the support cylinder and the coil, the elastic deformation triggered by the second spring is limited. However, by utilizing the different upward and downward movement steps of the support cylinder and the coil, the compression of the axial gap between the coils is satisfied first, then the clamping of the coil by the rack is satisfied, and finally, by using the linkage of the force transmission rod, the elastic force of the fifth inclined section and the elastic force of the first U-shaped bendable section are superimposed, so that the clamping force of the rack is further increased. This greatly improves the installation stability of the coil under limited conditions, reduces the axial vibration and collision between the coils, and reduces the crushing damage caused by excessive axial pressure on the coil.

[0023] Optionally, the upper end of the rack is provided with a sliding groove, and a slide bar is slidably connected in the groove along the radial direction of the support cylinder. The slide bar is located between the coil and the slide piece. One end of the slide bar is integrally formed with an elastic curved claw. The slide bar is provided with a plurality of inclined spring pieces evenly arranged along its own length direction. The outer wall of the support cylinder is provided with a mating groove for the elastic curved claw to be radially engaged. The lower surface of the slide piece is fixed with a plurality of guide teeth evenly arranged along its own radial direction. The inclined surface of the guide teeth fits against the inclined surface of the inclined spring pieces.

[0024] Through the above technical solution, during the downward movement of the slider under the elastic force of the fifth inclined section, the inclined surface of the guide tooth of the slider is in contact with the inclined surface of the inclined spring, and the downward movement trend of the slider will be transformed into the tendency to force the slider to move radially inward along the support cylinder. This causes the elastic claw of the slider to be radially engaged in the mating groove, thus completing the radial limiting of the slider. The slider is located between the coil and the slider, and the slider plays a filling role to axially limit the coil. Furthermore, the inclined spring is elastic, and the elastic potential energy accumulated by the inclined spring will be applied to the coil, making the axial limiting force of the coil more elastic and moderate, so as to reduce the occurrence of coil damage due to excessive axial limiting force.

[0025] Optionally, the shielding gap is 3-7mm.

[0026] Optionally, the housing includes an upper shell, the radially contracting section, and a lower shell from top to bottom. The inner diameter of the upper shell is smaller than that of the lower shell. The upper shell is fixed to the upper support insulator, and a first O-ring is provided at the mating position. The lower shell is fixed to the flange by the first bolt, and a second O-ring is provided at the mating position. The flange is fixed to the lower support insulator, and a third O-ring is provided at the mating position.

[0027] The above technical solutions can improve the sealing performance of the casing and reduce the leakage of insulating gas.

[0028] The beneficial effects of this application are:

[0029] 1. By setting up a rack, a first triangular tooth, and an elastic structure, the rack is guided to move radially outward through the cooperation of the first and second triangular teeth. The sidewall of the rack abuts against the inner circumferential surface of the coil to clamp each coil, thereby limiting the circumferential and radial movement of the coil. Furthermore, since the surface of the rack has a first rubber coating with a high coefficient of friction, the coil is axially limited by friction, which greatly improves the installation stability of the coil. Moreover, no additional tooling is required. During the installation of the support cylinder, when the support cylinder moves relative to the shell, the energy stored in the elastic structure is used to fix the coil, which is convenient. In addition, when the coil vibrates radially, the elastic structure will buffer the displacement trend of the rack, while the vertical displacement of the rack rubs against the coil, and the kinetic energy of the vibration is converted into frictional heat energy, thereby achieving a vibration reduction effect.

[0030] 2. The second inclined section first applies axial pressure to the coil to compress the gap between the coils. The fifth inclined section then abuts against the slider to complete the outward expansion of the rack. The rack radially clamps the coil. Next, the first bolt is loosened to move the support cylinder and the coil downward to relieve the axial pressure on the coil and reduce coil damage. At the same time, the force transmission rod is used to make the fifth inclined section and the second inclined section form a whole, so that the elastic force of the fifth inclined section and the elastic force of the first U-shaped bendable section are superimposed on the rack, further improving the clamping effect. This can be understood as follows: within the limited axial displacement space of the support cylinder and the coil, the elastic deformation triggered by the second spring is limited. However, by utilizing the different upward and downward movement steps of the support cylinder and the coil, the compression of the axial gap between the coils is satisfied first, then the clamping of the coil by the rack is satisfied, and finally, by using the linkage of the force transmission rod, the elastic force of the fifth inclined section and the elastic force of the first U-shaped bendable section are superimposed, so that the clamping force of the rack is further increased. This greatly improves the installation stability of the coil under limited conditions, reduces the axial vibration and collision between the coils, and reduces the crushing damage caused by excessive axial pressure on the coil. Attached Figure Description

[0031] Figure 1 is a cross-sectional view of the overall structure of Embodiment 1.

[0032] Figure 2 is a cross-sectional view along the AA direction in Figure 1.

[0033] Figure 3 is a magnified view of part B in Figure 1.

[0034] Figure 4 is a schematic diagram of the elastic structure of Example 1.

[0035] Figure 5 is a cross-sectional view of the support cylinder in Embodiment 2.

[0036] Figure 6 is a cross-sectional view of the overall structure of Embodiment 3.

[0037] Figure 7 is a magnified view of point C in Figure 6.

[0038] Figure 8 is a schematic diagram of the second spring in Embodiment 3.

[0039] Figure 9 is a schematic diagram of Example 3 showing the support cylinder moving upward to the initial contact state between the slider and the third folding section.

[0040] Figure 10 is a schematic diagram of the second spring in Embodiment 4.

[0041] Figure 11 is a partial cross-sectional view of Embodiment 4, illustrating the fit between the lower shell and the flange.

[0042] Figure 12 is a schematic diagram of Example 4 illustrating the changes in the state of the second spring after the support cylinder moves upward and retracts.

[0043] Figure 13 is a schematic diagram of Example 4 illustrating the change in the engagement state of the guide tooth and the inclined spring during the upward movement of the support cylinder.

[0044] Explanation of reference numerals in the attached drawings: 1. Mating gear assembly; 2. Rack; 3. Elastic structure; 10. Housing; 101. Upper housing; 1011. First O-ring; 1012. Second O-ring; 1013. Third O-ring; 102. Radial contraction section; 1021. Protrusion; 103. Lower housing; 104. Upper support insulator; 105. Lower support insulator; 106. Coil; 107. Support cylinder; 1071. Flange; 1072. Resin gasket; 1073. Strip groove; 1074. Spline; 108. First bolt; 1081. Threaded hole; 1082. Rubber ring; 11. First triangular tooth; 12. Resin sleeve; 13. 15. Keyway; 20. Mating groove; 21. Slide groove; 22. Second triangular tooth; 22. Slider; 221. Guide tooth; 23. Slip ring; 30. Second bolt; 31. Connecting ring; 32. First spring; 33. Second spring; 330. Third fold section; 331. First inclined section; 332. Second inclined section; 333. Third inclined section; 334. Fourth inclined section; 335. Fifth inclined section; 336. First U-shaped bendable section; 337. First fold section; 338. Second U-shaped bendable section; 339. Second fold section; 35. Force transmission rod; 36. One-way tooth; 37. Slide bar; 371. Elastic bending claw; 372. Inclined spring. Detailed Implementation

[0045] The embodiments of this application are described in detail below, and examples of the embodiments are shown in Figures 1-13.

[0046] In the description of this specification, the references to "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" refer to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] Example 1

[0048] Example 1 discloses a built-in current transformer, as shown in Figure 1. The built-in current transformer includes an upper support insulator 104, a housing 10, a lower support insulator 105, a support cylinder 107, multiple coils 106, a mating tooth assembly 1, a rack 2, a slider 22, and an elastic structure 3.

[0049] The housing 10 comprises, from top to bottom, an upper housing 101, a radially contracting section 102, and a lower housing 103. The upper housing 101, radially contracting section 102, and lower housing 103 are integrally cast. The inner diameter of the upper housing 101 is smaller than the inner diameter of the lower housing 103. The upper housing 101 is fixed to the upper support insulator 104 by bolts, and a first O-ring 1011 is provided at the mating position between the upper housing 101 and the upper support insulator 104. The support cylinder 107 is coaxially arranged with the lower housing 103. A flange 1071 is integrally formed on the lower outer wall of the support cylinder 107. An annular resin gasket 1072 is provided on the upper surface of the flange 1071. The flange 1071 is connected to the lower end of the lower housing 103 by a first bolt. The lower housing 103 is fixedly connected by bolt 108. Specifically, the lower end of the lower housing 103 has a threaded hole 1081 that mates with the first bolt 108. The threaded head of the first bolt 108 presses against the lower surface of the flange 1071. A second O-ring 1012 is provided at the mating position between the flange 1071 and the lower end of the lower housing 103. The flange 1071 is fixed to the lower support insulator 105 by bolts. A third O-ring 1013 is provided at the mating position between the flange 1071 and the lower support insulator 105. By providing the first O-ring 1011, the second O-ring 1012, and the third O-ring 1013, the sealing effect of the housing 10 is improved, thereby reducing insulation.

[0050] The vertical gap between the inner wall of the radial contraction section 102 and the upper port of the support cylinder 107 is a shielding gap, and the shielding gap is 3-7mm.

[0051] Multiple coils 106 are sequentially sleeved on the outside of the support cylinder 107 along the axial direction, with the lowest coil 106 pressing against the resin pad 1072.

[0052] As shown in Figures 2 and 3, a strip groove 1073 is axially opened through the outer circumferential surface of the support cylinder 107. The strip grooves 1073 are evenly arranged along the circumference of the support cylinder 107. The two opposite groove walls of the strip grooves 1073 have a third rubber coating (not shown in the figure). The mating gear assembly 1 includes multiple sets of first triangular teeth 11 evenly arranged along the circumference of the support cylinder 107. Each set of first triangular teeth 11 includes multiple first triangular teeth 11 evenly arranged along the axial direction of the support cylinder 107. The first triangular teeth 11 are fixedly connected to the outer wall of the support cylinder 107. In this embodiment, the first triangular teeth 11 are integrally formed on the bottom of the strip groove 1073. That is, the strip groove 1073 and the first triangular teeth 11 can be formed by machining. The inclined surface of the first triangular teeth 11 has a second rubber coating (not shown in the figure).

[0053] The rack 2 is parallel to the axis of the support cylinder 107. The rack 2 has multiple second triangular teeth 21. Both the first triangular teeth 11 and the second triangular teeth 21 are isosceles triangles. The surface of the rack 2 and the inclined surface of the second triangular teeth 21 are covered with a first rubber coating (not shown in the figure). The rack 2 slides into the strip groove 1073, and the surface of the first rubber coating of the rack 2 is in contact with the surface of the third rubber coating of the strip groove 1073. The groove wall of the strip groove 1073 not only restricts the circumferential deflection of the rack 2, but also has a certain coefficient of friction between the first rubber coating and the third rubber coating, so that the rack 2 is not easy to fall out after being assembled into the strip groove 1073, so that the rack 2 is deeply hidden in the strip groove 1073, and the outer diameter of the virtual circle formed by the racks 2 is small, so as to facilitate the insertion of the coil 106.

[0054] The slide plate 22 is annular, and a sliding ring 23 is integrally formed at the inner diameter of the slide plate 22. The sliding ring 23 is sleeved on the upper outer wall of the support cylinder 107, so that the slide plate 22 can slide axially relative to the support cylinder 107, and the upper end of each rack 2 abuts against the lower surface of the slide plate 22.

[0055] As shown in Figures 3 and 4, the elastic structure 3 is installed on the inner wall of the radial contraction section 102. In this embodiment, the elastic structure 3 includes a connecting ring 31 and a plurality of first spring pieces 32. The connecting ring 31 is fixed to the inner wall of the radial contraction section 102 by a second bolt 30. Each first spring piece 32 is evenly arranged along the circumference of the support cylinder 107. One end of the first spring piece 32 is integrally formed and connected to the connecting ring 31. The other end of the first spring piece 32 is inclined downward and extends toward the axis of the support cylinder 107. The lower end of the first spring piece 32 elastically presses against the upper surface of the slide plate 22.

[0056] During installation, the rack 2 is installed on the outside of the support cylinder 107. At this time, the inclined surface of the second triangular tooth 21 is completely in contact with the inclined surface of the first triangular tooth 11, the radial distance between the rack 2 and the support cylinder 107 is minimized, and the outer diameter of the virtual circle formed by the racks 2 is minimized. The rack 2 is less likely to interfere with the coil 106, thus facilitating the placement of the coil 106 on the outside of the support cylinder 107. At this time, there is a radial gap between the inner diameter of the rack 2 and the coil 106. Then, the slider 22 is placed on the upper end of the support cylinder 107. Ensure that the lower surface of the slider 22 abuts against the upper end of the rack 2, then install the support cylinder 107 into the housing 10. By tightening the first bolt 108, the head of the first bolt 108 abuts against the lower surface of the flange 1071, thereby causing the support cylinder 107 and the coil 106 to move upward relative to the housing 10. As the slider 22 moves upward with the support cylinder 107, it touches the end of the first spring 32. The first spring 32 accumulates elastic potential energy, and the elastic force of the first spring 32 is applied downward to the slider 22 (in Figure 3). (The arrow indicates the direction of the elastic force application). The slider 22 forces the rack 2 to move downward, changing the state from complete contact between the inclined surface of the second triangular tooth 21 and the inclined surface of the first triangular tooth 11 to partial contact between the inclined surface of the second triangular tooth 21 and the inclined surface of the first triangular tooth 11. At the same time, guided by the inclined surface of the first triangular tooth 11, the rack 2 moves radially outward along the support cylinder 107. The outer diameter of the virtual circle formed by the racks 2 is the largest. The sidewall of the rack 2 abuts against the inner circumferential surface of the coil 106 to hold each coil 106, thereby limiting the circumferential and radial movement of the coil 106. Furthermore, since the surface of the rack 2 has a first rubber coating with a large coefficient of friction, the friction force is used to axially limit the coil 106, thereby greatly improving the installation stability of the coil 106. Moreover, no additional tooling is required. That is, during the installation of the support cylinder 107, when the support cylinder 107 moves relative to the housing 10, the energy stored in the first spring 32 is used to complete the fixation of the coil 106, which is more convenient.

[0057] Secondly, since the elastic force of the first spring 32 is always applied to the rack 2, during use or transportation, when the coil 106 vibrates radially or axially, the rack 2 has a vertical displacement tendency, and the second triangular tooth 21 of the rack 2 and the first triangular tooth 11 of the support cylinder 107 undergo relative displacement. The elastic structure 3 will buffer the displacement tendency of the rack 2. The first rubber coating, the second rubber coating and the third rubber coating have a certain coefficient of friction, that is, the rack 2 and the groove wall of the strip groove 1073 undergo relative displacement friction, and the second triangular tooth 21 of the rack 2 and the first triangular tooth 11 of the support cylinder 107 undergo relative displacement friction. Friction generates heat to convert the kinetic energy of vibration into frictional heat energy, thereby achieving the shock absorption effect.

[0058] Example 2

[0059] As shown in Figure 5, the difference between Embodiment 2 and Embodiment 1 is that the mating gear assembly 1 also includes a resin sleeve 12, the outer wall of the support cylinder 107 has a spline 1074 protruding from it, and the inner wall of the resin sleeve 12 is provided with a keyway 13 that mates with the spline 1074.

[0060] Both the strip groove 1073 and the first triangular tooth 11 are provided on the outer wall of the resin sleeve 12.

[0061] In this way, the resin sleeve 12 can be integrally injection molded, which is relatively simple to manufacture, and the first triangular tooth 11 has high dimensional accuracy, which can improve the displacement accuracy of the rack 2, thereby improving the fixing accuracy of the coil 106.

[0062] Example 3

[0063] The difference between Embodiment 3 and Embodiment 1 is that, as shown in Figures 6, 7 and 8, the elastic structure 3 includes a connecting ring 31 and a plurality of second spring pieces 33. The connecting ring 31 is fixed to the inner wall of the radial contraction section 102 by a second bolt 30, and each second spring piece 33 is evenly arranged along the circumference of the support cylinder 107.

[0064] The second spring piece 33 includes, along the direction away from the connecting ring 31, a first inclined section 331, a first U-shaped bendable section 336, a second inclined section 332, a first folding section 337, a third inclined section 333, a second U-shaped bendable section 338, a fourth inclined section 334, a second folding section 339, a fifth inclined section 335, and a third folding section 330 connected in sequence. The first inclined section 331 and the second inclined section 332 are both inclined downwards, the third inclined section 333 and the fourth inclined section 334 are both inclined upwards, and the fifth inclined section 335 is inclined downwards. The inner wall of the radial contraction section 102 is integrally formed with a protrusion 1021, which is semi-circular and abuts against the side of the fourth inclined section 334.

[0065] When the first bolt 108 is tightened, the bolt head of the first bolt 108 abuts against the lower surface of the flange 1071, thereby causing the flange 1071 to move upward relative to the housing 10, which in turn causes the support cylinder 107 and the coil 106 to move upward relative to the housing 10. During this process, the upper surface of the slide 22 first abuts against the outer arc surface of the third fold section 330 (at this time, the coil 106 has not yet contacted the first fold section 337, see Figure 9 for details). The elastic force of the fifth inclined section 335 forces the slide 22 to move downward through the third fold section 330, so as to change the state in which the inclined surface of the second triangular tooth 21 is completely in contact with the inclined surface of the first triangular tooth 11 to the state in which the inclined surface of the second triangular tooth 21 is partially in contact with the inclined surface of the first triangular tooth 11. During this state switching process, under the guidance of the inclined surface of the first triangular tooth 11, the rack 2 moves radially outward along the support cylinder 107, thereby restricting the circumferential and radial movement of the coil 106.

[0066] Continue tightening the first bolt 108 to move the support cylinder 107 and coil 106 upwards. The fifth inclined section 335 continues to accumulate elastic potential energy, forcing the rack 2 to continue moving radially outwards. The outer diameter of the virtual circle formed by the racks 2 is at its maximum. The sidewalls of the racks 2 abut against the inner circumference of the coil 106 to clamp each coil 106, and the clamping force increases. The surface of the coil 106 begins to abut against the outer arc surface of the first folding section 337 (see Figure 7). The first U-shaped bendable section 336 is elastically compressed, and the second inclined section 332 and the third inclined section 333 deflect upwards. The elastic force of the first U-shaped bendable section 336 passes through the second inclined section 332 and the first folding section 337. 7. This forces each coil 106 to be axially pressed together, thereby reducing the axial gap between each coil 106 and reducing the occurrence of vibration and collision of the coil 106 due to the axial gap. At the same time, the upward deflection of the third inclined section 333 will drive the fourth inclined section 334 and the fifth inclined section 335 to deflect downward with the protrusion 1021 as the fulcrum (while the second U-shaped bendable section 338 is elastically compressed). The downward deflection of the fifth inclined section 335 further applies downward pressure to the slide plate 22 and the rack 2 through the third folding section 330, further increasing the clamping force of the rack 2 on the coil 106, thereby improving the installation stability of the coil 106.

[0067] It can be understood that within the limited axial displacement space of the support cylinder 107 and the coil 106, the elastic deformation triggered by the second spring 33 is limited. However, by increasing the linkage of the second inclined section 332, the fourth inclined section 334, the fifth inclined section 335 and the protrusion 1021, the clamping force of the fifth inclined section 335 on the rack 2 is further increased, thereby greatly improving the installation stability of the coil 106 under limited conditions.

[0068] Example 4

[0069] The difference between Example 4 and Example 3 is shown in Figure 10. The length of the fifth inclined segment 335 in Example 4 is less than the length of the fifth inclined segment 335 in Example 3, and the thickness of the fifth inclined segment 335 is less than the thickness of the second inclined segment 332.

[0070] Furthermore, the elastic structure 3 also includes a force transmission rod 35. The two force transmission rods 35 are located on both sides of the width direction of the second inclined section 332. One end of the force transmission rod 35 is welded and fixed to the middle of the side of the second inclined section 332. The other end of the force transmission rod 35 is fixed with a plurality of one-way teeth 36 arranged at equal intervals along its own length direction. The one-way teeth 36 are right-angled triangles. The tip of the one-way teeth 36 is set further away from the second inclined section 332 than the thick end of the one-way teeth 36. The side of the fifth inclined section 335 is inserted into the gap between two adjacent one-way teeth 36.

[0071] As shown in Figure 11, there is a fitting gap between the lower end of the housing 10 and the flange 1071, and a rubber ring 1082 is clamped in the fitting gap. The rubber ring 1082 is located outside the first rubber ring 1082.

[0072] As shown in Figure 12, when the first bolt 108 is tightened, the bolt head of the first bolt 108 abuts against the lower surface of the flange 1071, causing the flange 1071 to move upward relative to the housing 10, thereby causing the support cylinder 107 and the coil 106 to move upward relative to the housing 10. During this process, the surface of the coil 106 first abuts against the outer arc surface of the first fold section 337 (the upper surface of the slider 22 has not yet contacted the third fold section 330, see the first state diagram in Figure 12), the first U-shaped bendable section 336 is elastically compressed, and the second inclined section 332 and the third inclined section 333 deflect upward (see the second state diagram in Figure 12). The upward deflection of the second inclined section 332 causes the force transmission rod 35 to move relative to the fifth inclined section 335. The teeth 36 elastically avoid the fifth inclined section 335 in sequence, and the elastic force of the first U-shaped bendable section 336 forces each coil 106 to be axially compressed through the second inclined section 332 and the first fold-back section 337, thereby reducing the axial gap between each coil 106 and reducing the occurrence of vibration and collision of the coil 106 due to the axial gap. The first bolt 108 is tightened to make the support cylinder 107 continue to move upward until the rubber ring 1082 is in a fully compressed state. During this process, the upper surface of the slide 22 abuts against the outer arc surface of the third fold-back section 330, and the elastic force of the fifth inclined section 335 forces the slide 22 to move downward through the third fold-back section 330, so that the inclined surface of the second triangular tooth 21 and the first triangular tooth 21 are aligned. The state of complete contact between the inclined surfaces of tooth 11 and the first triangular tooth 11 changes to a state of partial contact between the inclined surfaces of the second triangular tooth 21 and the first triangular tooth 11 (see the second state diagram in Figure 12). During this state transition, guided by the inclined surfaces of the first triangular tooth 11, the rack 2 moves radially outward along the support cylinder 107, thereby restricting the circumferential and radial movement of the coil 106. Then, the first bolt 108 is loosened (see the third state diagram in Figure 12), and the support cylinder 107 and the coil 106 move downward until the rubber ring 1082 is in a partially compressed state (the compression degree of the rubber ring 1082 is 30% to 70% of full compression). After the first fold-back section 337 loses the contact of the coil 106, the first fold-back section 337 has room to move. This causes the first U-shaped bendable section 336 to recover some elastic deformation, and the second inclined section 332 to deflect downwards (see the third state diagram in Figure 12). Since the side of the second inclined section 332 is stuck at the coarse end of the one-way tooth 36, the second inclined section 332 will drive the fifth inclined section 335 to deflect downwards together. The downwardly deflected fifth inclined section 335 further applies downward pressure to the slider 22 and the rack 2 through the third folding section 330, further increasing the clamping force of the rack 2 on the coil 106, thereby improving the installation stability of the coil 106. Finally, there is a gap between the outer arc surface of the first folding section 337 and the coil 106, that is, the coil 106 is not subjected to axial pressure, thereby reducing the occurrence of axial pressure damage to the coil 106.

[0073] In summary, during the installation process, the second inclined section 332 first applies axial pressure to the coils 106 to compress the gap between them. The fifth inclined section 335 then abuts against the slide plate 22 to complete the outward expansion of the rack 2. The rack 2 radially clamps the coils 106. Next, the first bolt 108 is loosened to move the support cylinder 107 and the coils 106 downward to relieve the axial pressure on the coils 106 and reduce damage to them. At the same time, the force transmission rod 35 makes the fifth inclined section 335 and the second inclined section 332 form a whole, so that the elasticity of the fifth inclined section 335 and the elasticity of the first U-shaped bendable section 336 are superimposed on the rack 2, further improving the clamping effect.

[0074] This can be understood as follows: within the limited axial displacement space of the support cylinder 107 and the coil 106, the elastic deformation triggered by the second spring 33 is limited. However, by utilizing the different upward and downward movement steps of the support cylinder 107 and the coil 106, the compression of the axial gap between the coils 106 is satisfied first, then the clamping of the coil 106 by the rack 2 is satisfied, and finally, by utilizing the linkage of the force transmission rod 35, the elastic force of the fifth inclined section 335 and the elastic force of the first U-shaped bendable section 336 are superimposed, so that the clamping force of the rack 2 is further increased, thereby greatly improving the installation stability of the coil 106 under limited conditions, reducing the axial vibration and collision between the coils 106, and reducing the crushing damage caused by excessive axial pressure on the coil 106.

[0075] Example 5

[0076] The difference between Embodiment 5 and Embodiment 4 is that, as shown in Figure 13, a groove 20 is provided at the upper end of the rack 2, and a slide bar 37 is connected to the groove 20 in a radial direction along the support cylinder 107. That is, after the coil 106 is sleeved on the outside of the support cylinder 107, the slide bar 37 and the slide plate 22 are placed in sequence, so that the slide bar 37 is located between the coil 106 and the slide plate 22.

[0077] The upper surface of the slider 37 is fixed with a plurality of inclined spring pieces 372 evenly arranged along its own length direction, and the lower surface of the slider 22 is fixed with a plurality of guide teeth 221 evenly arranged along its own radial direction. The guide teeth 221 are right-angled triangles, and the inclined surface of the guide teeth 221 is in contact with the inclined surface of the inclined spring pieces 372.

[0078] One end of the slide bar 37 is integrally formed with an elastic curved claw 371, and the outer wall of the support cylinder 107 is provided with a mating groove 15 for the elastic curved claw 371 to be radially engaged.

[0079] During the downward movement of the slider 22 under the elastic force of the fifth inclined section 335, since the inclined surface of the guide tooth 221 of the slider 22 is in contact with the inclined surface of the inclined spring 372, the downward movement trend of the slider 22 will be transformed into a trend that forces the slider 37 to move radially inward along the support cylinder 107, so that the elastic claw 371 of the slider 37 radially engages in the mating groove 15. Specifically, the elastic claw 371 elastically avoids the protrusion in the mating groove 15, and the inner arc surface of the elastic claw 371 is in contact with the mating groove 15. The protrusion within 5 completes the radial limiting of the slider 37. Since the slider 37 is located between the coil 106 and the slider 22, the lower surface of the slider 37 is in contact with the upper surface of the coil 106. The slider 37 plays a filling role to axially limit the coil 106. Therefore, even if the whole installation is completed and there is no pressure from the first folding section 337 (after the first bolt 108 is loosened to the point that the support cylinder 107 and the coil 106 have moved down a certain distance), the coil 106 can still maintain the axial limiting.

[0080] Furthermore, the inclined spring 372 is elastic, and the elastic potential energy accumulated by the inclined spring 372 will be applied to the slider 22. The slider 22 has a downward reaction force on the slider 37. This downward reaction force is applied to the coil 106, making the axial limiting force of the coil 106 more elastic and moderate, so as to reduce the occurrence of coil 106 being damaged due to excessive axial limiting force.

[0081] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A built-in current transformer, characterized in that, The system includes an upper support insulator (104), a housing (10), a lower support insulator (105), a support cylinder (107), multiple coils (106), a gear assembly (1), a rack (2), a sliding plate (22), and an elastic structure (3). The support cylinder (107) is coaxially arranged with the housing (10). A flange (1071) is integrally formed on the lower outer wall of the support cylinder (107). An annular resin gasket (1072) is provided on the upper surface of the flange (1071). The flange (1071) is fixedly connected to the lower end of the housing (10) by a first bolt (108). 10) The lower end has a threaded hole (1081) that mates with the first bolt (108), and the head of the first bolt (108) presses against the lower surface of the flange (1071); the housing (10) includes a radially contracting section (102), and the vertical gap between the inner wall of the radially contracting section (102) and the upper port of the support cylinder (107) is a shielding gap; multiple coils (106) are sequentially sleeved on the outside of the support cylinder (107) along the axial direction, and the lowermost coil (106) presses against the resin pad (1072). The mating tooth assembly (1) includes multiple coils evenly arranged along the axial direction of the support cylinder (107). The first triangular tooth (11) is fixedly connected to the outer wall of the support cylinder (107). The rack (2) is parallel to the axis of the support cylinder (107). The surface of the rack (2) has a first rubber coating. The rack (2) has multiple second triangular teeth (21). The slide plate (22) is axially slidingly engaged with the support cylinder (107). The upper end of each rack (2) abuts against the lower surface of the slide plate (22). The elastic structure (3) is installed on the inner wall of the radial contraction section (102). The elastic force of the elastic structure (3) is used to force the rack (2) to move downward to tilt the inclined surface of the second triangular teeth (21). The state of complete contact with the inclined surface of the first triangular tooth (11) is changed to the state of partial contact between the inclined surface of the second triangular tooth (21) and the inclined surface of the first triangular tooth (11). When the inclined surface of the second triangular tooth (21) is partially contacted with the inclined surface of the first triangular tooth (11), the side wall of the rack (2) abuts against the inner circumferential surface of the coil (106). The elastic structure (3) includes a connecting ring (31) and a plurality of second spring pieces (33). The connecting ring (31) is fixed to the inner wall of the radial contraction section (102) by a second bolt (30). Each second spring piece (33) is evenly arranged along the circumference of the support cylinder (107).The second spring (33) includes, along the direction away from the connecting ring (31), a first inclined section (331), a first U-shaped bendable section (336), a second inclined section (332), a first fold-back section (337), a third inclined section (333), a second U-shaped bendable section (338), a fourth inclined section (334), a second fold-back section (339), a fifth inclined section (335), and a third fold-back section (330), connected in sequence. The first inclined section (331) and the second inclined section (332) are... All sections are inclined downwards, the third inclined section (333) and the fourth inclined section (334) are inclined upwards, and the fifth inclined section (335) is inclined downwards. A protrusion (1021) is fixed to the inner wall of the radial contraction section (102), and the protrusion (1021) abuts against the side of the fourth inclined section (334). During the process of tightening the first bolt (108) to drive the support cylinder (107) and the coil (106) to move upwards relative to the housing (10), the The upper surface of the slider (22) first abuts against the outer arc surface of the third fold section (330). The elastic force of the fifth inclined section (335) forces the slider (22) to move downward through the third fold section (330), so as to change the state in which the inclined surface of the second triangular tooth (21) and the inclined surface of the first triangular tooth (11) are completely in contact with each other to the state in which the inclined surface of the second triangular tooth (21) and the inclined surface of the first triangular tooth (11) are partially in contact. At this time, the surface of the coil (106) abuts against the first fold section (337) again. The outer arc surface of the coil (106) is elastically compressed by the first U-shaped bendable section (336), and the second inclined section (332) and the third inclined section (333) deflect upwards. The elastic force of the first U-shaped bendable section (336) forces each coil (106) to be axially compressed through the second inclined section (332) and the first fold-back section (337). The upward deflection of the third inclined section (333) will cause the fourth inclined section (334) and the fifth inclined section (335) to deflect downwards with the protrusion (1021) as the fulcrum.

2. The built-in current transformer according to claim 1, characterized in that, The inclined surface of the first triangular tooth (11) has a second rubber coating, and the inclined surface of the second triangular tooth (21) has the first rubber coating.

3. The built-in current transformer according to claim 2, characterized in that, The outer circumferential surface of the support cylinder (107) is axially perforated with a strip groove (1073), and the bottom of the strip groove (1073) is integrally formed with the first triangular tooth (11); the two opposite groove walls of the strip groove (1073) have a third rubber coating, and the surface of the first rubber coating of the toothed rack (2) is in contact with the surface of the third rubber coating of the strip groove (1073).

4. The built-in current transformer according to claim 2, characterized in that, The mating gear assembly (1) further includes a resin sleeve (12), the outer wall of the support cylinder (107) is provided with a spline (1074), the inner wall of the resin sleeve (12) is provided with a keyway (13) that mates with the spline (1074); the outer wall of the resin sleeve (12) is axially provided with a strip groove (1073), the bottom of the strip groove (1073) is integrally formed with the first triangular tooth (11); the two opposite groove walls of the strip groove (1073) are provided with a third rubber coating, and the surface of the first rubber coating of the gear rack (2) is in contact with the surface of the third rubber coating of the strip groove (1073).

5. The built-in current transformer according to claim 1, characterized in that, The shielding gap is 3-7mm.

6. The built-in current transformer according to claim 1, characterized in that, The housing (10) comprises, from top to bottom, an upper housing (101), a radially contracting section (102), and a lower housing (103). The inner diameter of the upper housing (101) is smaller than that of the lower housing (103). The upper housing (101) is fixed to the upper support insulator (104), and a first O-ring (1011) is provided at the mating position. The lower housing (103) is fixedly connected to the flange (1071) by the first bolt (108), and a second O-ring (1012) is provided at the mating position. The flange (1071) is fixed to the lower support insulator (105), and a third O-ring (1013) is provided at the mating position.

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