A mutual inductor coil and terminal anti-deviation pouring positioning device for ring network cabinet

Abstract

The application relates to the technical field of intelligent power grid power distribution equipment manufacturing, and discloses a mutual inductor coil and terminal anti-deviation pouring positioning device for ring network cabinets, which comprises a mutual inductor assembly and a mold assembly, the mold assembly comprises a fixed mold, a movable mold and a terminal groove, and the mutual inductor assembly comprises an insulating base, a coil assembly, a conductor and a terminal; the peripheral sidewall of the terminal is provided in a conical slope, the inner wall of the terminal groove is provided with a matching conical positioning surface, the bottom of the terminal is provided with a pressure collection cavity, and a movable compensation assembly is arranged between the terminal and the conductor; the lower end of the fixed mold is provided with a pushing assembly and a locking assembly; when the mold is closed, the locking assembly first presses the insulating base against the bottom wall in the inner cavity of the fixed mold, and then the pushing assembly pushes the conductor and the terminal to ascend, so that the terminal is guided and centered in the terminal groove. The device can improve the terminal positioning fault tolerance, the sealing performance of the terminal groove and the anti-loosening ability of the terminal after solidification.

Description

Technical Field

[0001] This invention relates to the field of smart grid power distribution equipment manufacturing technology, and in particular to a casting and positioning device for preventing the offset of transformer coils and terminals in a ring main unit. Background Technology

[0002] Ring main units (RMUs) are widely used in distribution networks, smart grids, and urban power terminal distribution systems. Their internal instrument transformers are primarily used for acquiring, measuring, and protecting the current signals in the primary circuit. The accuracy of the transformer's terminal positions and the quality of its insulation casting directly affect subsequent busbar connections, internal assembly consistency, and operational reliability. RMUs typically employ epoxy resin casting, where the coil assembly, conductors, terminals, and insulation support structure are pre-assembled and placed into a casting mold, then cured with epoxy resin to form a unified insulating shell. For example... Figure 1 As shown, this is the overall structure of a current transformer after casting. The upper terminal part is a rectangular plate or columnar structure. This type of terminal is easy to connect with the busbar, copper busbar or wiring component in the cabinet by surface contact bolt. It has the characteristics of large contact area, easy control of current carrying cross section, convenient processing of bolt holes and good compatibility with the rectangular busbar in the cabinet. Therefore, it is widely used in ring main unit current transformers.

[0003] In existing casting and positioning processes, the coil assembly, conductor, terminals, and insulating base are typically formed into a current transformer assembly first. Then, structures such as positioning pins, positioning holes, positioning protrusions, positioning recesses, limiting steps, or pads are used to place it into the mold forming cavity. These structures provide basic positioning for the current transformer assembly, ensuring the coil assembly and insulating base are roughly in their predetermined positions. However, machining errors of the terminals themselves, connection errors between the terminals and conductors, assembly errors between the conductors and coil assemblies, and initial positioning errors of the current transformer assembly in the mold can still be transmitted to the exposed section of the terminals, causing local mismatch between the rectangular terminals and the corresponding terminal slots on the mold. Since rectangular terminals and rectangular terminal slots usually require high contour matching accuracy to ensure the exposed height, exposed position, and casting boundary around the terminal slot, when there is a small deviation in the exposed section of the terminal, the terminal is prone to hard contact, scraping, or jamming with the edge of the terminal slot during entry into the terminal slot, affecting the terminal's performance. Surface quality and molding efficiency are important considerations. Meanwhile, ordinary rectangular terminals rely primarily on lateral restraints to maintain contact with the terminal slot, lacking a structure capable of continuously generating adhesion. This results in insufficient sealing stability around the terminal slot during casting, easily leading to issues such as epoxy resin overflow, contamination of the exposed terminal surface, or insufficient stability of the terminal root coating. Furthermore, after casting and curing, the terminals still need to be connected to external busbars or connectors via bolts. If the terminal root is only fixed to the epoxy resin casting body using ordinary coating, there is still a risk of loosening of the terminal relative to the casting body, changes in posture, or insufficient pull-out stability under tension, torsion, or vibration conditions. Summary of the Invention

[0004] The technical problem to be solved by this invention is that in the existing casting and positioning of current transformers in ring main units, the exposed section of the rectangular terminal is prone to partial mismatch with the mold terminal slot due to terminal processing, conductor connection and initial positioning error of the current transformer assembly. This leads to hard contact, scraping or jamming when the terminal enters the terminal slot, and there are also problems with insufficient sealing stability around the terminal slot and insufficient pull-out and loosening resistance after the terminal is cured. To address this, we propose a casting and positioning device for preventing offset of current transformer coil and terminal in ring main units.

[0005] To achieve the above objectives, this application adopts the following technical solution: a casting and positioning device for anti-offset of transformer coil and terminal for ring main unit, including transformer assembly and mold assembly for accommodating transformer assembly, the mold assembly including fixed mold, moving mold corresponding to fixed mold and terminal slots disposed on fixed mold and moving mold;

[0006] The current transformer assembly includes an insulating base, a coil assembly mounted on the insulating base, a conductor vertically and movably connected to the insulating base, and a terminal connected to the upper end of the conductor.

[0007] The terminal has a tapered sidewall, the inner wall of the terminal slot has a tapered positioning surface that matches the tapered sidewall of the terminal, and the bottom of the terminal has a pressing cavity that communicates with the forming cavity.

[0008] A movable compensation component is provided between the terminal and the conductor. The movable compensation component is used to enable the terminal to generate a compensation movement relative to the conductor within a predetermined range while maintaining electrical connection with the conductor.

[0009] The fixed mold is provided with a pusher assembly at its lower end. The pusher assembly is used to push the conductor and terminal upward in the vertical direction according to the closing action of the moving mold, so that the terminal can be guided and centered by cooperating with the tapered positioning surface of the terminal slot through the tapered inclined surface.

[0010] A pre-positioning component is provided between the inner cavity bottom wall of the fixed mold and the insulating seat. A locking component is also provided at the lower end of the fixed mold. The locking component is used to press the insulating seat onto the inner cavity bottom wall of the fixed mold before the pushing component pushes the conductor and terminal upward.

[0011] Preferably, the top of the terminal is a rectangular exposed wiring portion, and the cross-sectional area of ​​the lower end of the terminal is larger than the cross-sectional area of ​​the upper end of the terminal, so that the terminal forms a frustum-shaped structure that is smaller at the top and larger at the bottom;

[0012] The pressure chamber is a tapered flared groove formed at the bottom of the terminal. The pressure chamber is used to withstand the pressure of the epoxy resin casting material after it enters, so that the terminal tends to abut against the tapered positioning surface of the terminal groove.

[0013] Preferably, the movable compensation component includes a hollow groove disposed at the bottom of the terminal and a movable disk disposed at the top of the conductor.

[0014] Preferably, the movable compensation component further includes a limiting step disposed at the opening of the hollow groove, with the movable plate located inside the limiting step, allowing the movable plate to slide relative to the terminal within the range defined by the hollow groove.

[0015] Preferably, the push assembly includes an installation cavity disposed on the inner side of the lower end of the fixed mold, a wedge-shaped drive body movably disposed on the lower end of the inner side of the installation cavity along the displacement direction of the moving mold, a wedge-shaped force-bearing body vertically movably disposed on the upper end of the inner side of the installation cavity, an active push column disposed on the wedge-shaped force-bearing body, and a driven push column disposed at the bottom of the conductor.

[0016] The end of the wedge-shaped drive body near the moving mold can protrude from the side wall of the fixed mold, and can push the wedge-shaped drive body to move when the moving mold closes to the fixed mold;

[0017] The driven jacking column extends downward to the bottom of the insulating base and is correspondingly arranged with the active jacking column;

[0018] The wedge-shaped drive body cooperates with the inclined surface of the wedge-shaped force-bearing body. When the wedge-shaped drive body is pushed, it can drive the wedge-shaped force-bearing body to rise, and cause the active push column to push the driven push column to rise. The driven push column drives the conductor and terminal to rise.

[0019] Preferably, the active jacking column is vertically and movably connected to the wedge-shaped force-bearing body, and a first elastic structure is provided on the outer side of the upper end of the active jacking column;

[0020] The first elastic structure is used to generate an elastic jacking force when the driven jacking column is pushed on the active jacking column.

[0021] Preferably, the pre-positioning component includes a positioning pin disposed on the bottom wall of the fixed mold cavity and a positioning groove disposed on the bottom of the insulating seat;

[0022] The positioning pin can be inserted into the positioning slot to initially position the insulating seat.

[0023] Preferably, the locking assembly includes a push pin installed on the wedge-shaped force-bearing body and corresponding to the positioning pin, a locking cone vertically and movably disposed inside the positioning pin, and a locking block radially and movably disposed inside the upper sidewall of the positioning pin.

[0024] The lower end of the positioning groove is a cylindrical section that fits into the positioning pin, and the upper end of the positioning groove is a tapered expansion section.

[0025] The pusher is used to push the locking cone upward. The upper end of the locking cone is conical. The end of the locking block near the axis of the positioning pin slides with the locking cone. The end of the locking block away from the axis of the positioning pin can extend to the outside of the positioning pin and cooperate with the inclined surface of the inner wall of the conical expansion section of the positioning groove to press the insulating seat onto the bottom wall of the inner cavity of the fixed mold.

[0026] Preferably, the push column is movably connected to the locking cone, and a second elastic structure is provided between the bottom of the locking cone and the top of the wedge-shaped force-bearing body;

[0027] When the wedge-shaped force-bearing body rises, the jacking column first pushes the locking cone to rise and drives the locking block to extend, and then the active jacking column pushes the driven jacking column to rise.

[0028] Preferably, the positioning pin is vertically and movably connected to the bottom wall of the inner cavity of the fixed mold;

[0029] The jacking column has a T-shaped structure and is inseparably connected to the locking cone;

[0030] When the wedge-shaped force-bearing body moves downward, it can drive the locking cone to move downward through the push column, causing the locking block to retract and release the pressure on the positioning groove. When the wedge-shaped force-bearing body continues to move downward, it can drive the positioning pin to exit from the positioning groove or hide below the bottom wall of the molding cavity of the fixed mold through the push column.

[0031] The technical effects and advantages of this invention are as follows:

[0032] This invention designs the terminal as a frustoconical structure with a smaller top and a larger bottom, and forms a matching conical positioning surface in the terminal slot. This allows the terminal to be guided, corrected, and centered during its vertical upward movement into the terminal slot, thereby reducing the risk of hard contact, scratching, or jamming between the terminal and the terminal slot due to processing errors, conductor connection errors, or initial positioning errors of the transformer assembly. In addition, the refractory material entering the bottom pressure cavity of the terminal forms an auxiliary abutment, further improving the continuous fit between the terminal and the terminal slot and the stability of the sealant, reducing refractory material overflow and contamination of the exposed terminal surface. After casting and curing, the large-section frustoconical part at the lower end of the terminal is covered with epoxy resin to form an inverted anchoring structure, which helps to improve the resistance to pull-out, torsion, and loosening during subsequent bolt connection of the terminal.

[0033] This invention also sequentially completes the locking of the insulating seat and the pushing of the terminal through the mold closing action. First, the wedge-shaped drive body drives the wedge-shaped force-bearing body to rise, causing the pusher to push the locking cone to move, and the locking block to extend and press against the inner wall of the conical expansion section of the positioning groove, thereby pressing the insulating seat against the bottom wall of the fixed mold. The second elastic structure can continuously maintain the pre-tight fit between the insulating seat and the bottom wall of the fixed mold through the locking cone and the locking block, so that the insulating seat and the coil assembly form a stable reaction force reference. This avoids the current transformer assembly from floating up, detaching from the positioning pin, or becoming skewed when the active pusher pushes the conductor and terminal through the driven pusher pusher. It can also reduce the possibility of the casting material entering the gap between the insulating seat and the bottom wall of the fixed mold, making the connection between the bottom pre-positioning, elastic locking, terminal centering, casting sealing and subsequent demolding process more stable. Attached Figure Description

[0034] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0035] Figure 1 This is a schematic diagram of the structure of a prior art current transformer of the present invention;

[0036] Figure 2 This is a schematic diagram of the overall structure of the mold assembly and the current transformer assembly in the working state of the present invention;

[0037] Figure 3 This is a structural schematic diagram of the mold assembly and the current transformer assembly in their disassembled state according to the present invention;

[0038] Figure 4 For the present invention Figure 3 A structural diagram from another perspective based on the above;

[0039] Figure 5 This is a schematic diagram of the longitudinal section structure of the lower end of the fixed mold of the present invention;

[0040] Figure 6 This is a schematic diagram of the positioning groove of the present invention;

[0041] Figure 7 This is a schematic diagram of the structure of the terminal and conductor of the present invention in a disassembled state;

[0042] Figure 8 This is a schematic diagram of the overall structure of the current transformer assembly after molding according to the present invention;

[0043] Figure 9 This is a schematic diagram showing the mating state between the molded terminal and the epoxy resin of the present invention.

[0044] Legend: 1. Fixed mold; 2. Moving mold; 3. Terminal; 4. Insulating seat; 5. Coil assembly; 6. Conductor; 7. Wedge-shaped drive body; 8. Positioning pin; 9. Terminal slot; 10. Driven pusher; 11. Wedge-shaped force-bearing body; 12. Active pusher; 13. Mounting cavity; 14. Locking cone; 15. Locking block; 16. Positioning slot; 17. Pusher; 18. Movable plate; 19. First elastic structure; 20. Second elastic structure; 21. Hollow slot. Detailed Implementation

[0045] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0046] Reference Figures 2-9 As shown, the present invention provides a technical solution: a casting and positioning device for anti-offset of transformer coils and terminals in a ring main unit, comprising a mold assembly and a transformer assembly. The molding cavity of the mold assembly is used to accommodate the transformer assembly and to supply epoxy resin casting material. The epoxy resin casting material can be an insulating casting material formed by mixing epoxy resin, curing agent and insulating filler. In actual production, the mold assembly after mold closing can be placed as a whole in a vacuum casting equipment for epoxy resin vacuum casting. The vacuum casting equipment is used to vacuum, heat and insulate the environment where the mold assembly is located, and to supply casting material. It is a conventional and mature equipment in the field of epoxy casting of transformers. This embodiment will not impose too many restrictions on its specific tank structure and material supply system.

[0047] The mold assembly includes a fixed mold 1 and a movable mold 2 located on one side of the fixed mold 1 and corresponding to the fixed mold 1. The fixed mold 1 and the movable mold 2 are provided with corresponding terminal slots 9. After the fixed mold 1 and the movable mold 2 are closed, they together form a molding cavity for forming the epoxy resin casting body of the transformer assembly. The terminal slot 9 is located in the upper area of ​​the molding cavity. The terminal slot 9 is used to accommodate the exposed wiring part of the terminal 3, so that the upper end of the terminal 3 can protrude from the outside of the epoxy resin casting body after casting, so as to be subsequently connected to the busbar, copper busbar or wiring component in the ring main unit by bolts.

[0048] The current transformer assembly includes an insulating base 4, on which a coil assembly 5 is mounted. A conductor 6 is disposed on the insulating base 4. The lower end of the conductor 6 is electrically connected to the coil assembly 5, and the upper end of the conductor 6 is connected to a terminal 3, thereby realizing the electrical connection between the terminal 3 and the coil assembly 5. The coil assembly 5 may include an iron core, a winding, and an insulating covering structure that cooperates with the winding. The conductor 6 is used to form a primary-side conductive connection or lead-out connection between the terminal 3 and the coil assembly 5. The insulating base 4 is used to support the coil assembly 5, the conductor 6, and the terminal 3, and provides an initial bottom positioning reference when the current transformer assembly is placed into the mold assembly.

[0049] It should be noted that the terminals of the current transformers used in ring main units usually need to be connected to the busbars, copper busbars or wiring components inside the cabinet by surface contact bolts. Therefore, the exposed wiring part of terminal 3 usually adopts a rectangular column or rectangular sheet metal structure. This type of rectangular structure has the advantages of large contact area, easy processing of bolt holes, easy stacking and connection with rectangular busbars, and easy control of current carrying cross section. Correspondingly, the upper end of the mold assembly usually needs to be provided with terminal groove 9 corresponding to the exposed contour of terminal 3 to ensure the stability of the exposed height, exposed position of terminal 3 and the surrounding casting boundary of terminal groove 9. However, there may be small errors in the machining of terminal 3 itself, the connection between terminal 3 and conductor 6, the connection between conductor 6 and coil assembly 5, and the initial positioning of the transformer assembly in the mold assembly. After such errors are transmitted to the exposed area of ​​terminal 3, they can easily cause local mismatch between terminal 3 and terminal slot 9. If both terminal 3 and terminal slot 9 are simple rectangular rigid fit structures, terminal 3 is prone to hard contact, scraping or jamming with the edge of terminal slot 9 during mold closing or positioning. In addition, there is a lack of continuous adhesion between terminal 3 and terminal slot 9, and the sealing stability around terminal slot 9 during casting is also difficult to be fully guaranteed.

[0050] To this end, the present invention sets the four sides of terminal 3 as tapered slopes without changing the rectangular wiring area at the upper end of terminal 3 for external wiring, so that terminal 3 is truncated pyramidal in shape. Specifically, the top of terminal 3 is a rectangular exposed wiring part, the lower cross-sectional area of ​​terminal 3 is larger than its upper cross-sectional area, and the four sides of terminal 3 gradually slope outward from the upper end to the lower end, thereby forming a truncated pyramidal positioning part that is smaller at the top and larger at the bottom. Correspondingly, the inner wall of terminal groove 9 is set as a tapered positioning surface that matches the tapered slope of terminal 3. Terminal groove 9 gradually shrinks from bottom to top, so that when terminal 3 enters terminal groove 9 upward, it can be guided, corrected and centered by the mutually cooperating tapered slopes.

[0051] When the insulating base 4, coil assembly 5, and terminal 3 are placed in the mold assembly, the top wall of terminal 3 is lower than terminal slot 9, and conductor 6 is vertically and movably connected to the insulating base 4. The bottom of the mold assembly is provided with a push assembly for driving the terminal 3 and conductor 6 to rise as a whole. When the mold assembly is closed, the push assembly realizes the rise of terminal 3, thereby enabling the terminal 3 to automatically center and guide itself by engaging with the tapered inclined surface of terminal slot 9. Since terminal 3 enters terminal slot 9 in a vertical direction, the tapered contact between terminal 3 and terminal slot 9 can convert the horizontal deviation of terminal 3 relative to terminal slot 9 into a limited compensation displacement, thereby improving the fault tolerance of terminal 3 entering terminal slot 9.

[0052] To accommodate the displacement of terminal 3 during alignment, the bottom of terminal 3 is movably connected to conductor 6 via a movable compensation component. Terminal 3 can undergo a certain degree of horizontal displacement with conductor 6 through the movable compensation component. The movable compensation component includes a circular hollow groove 21 at the bottom of terminal 3, and a movable disk 18 at the top of conductor 6 that movably engages with the hollow groove 21. Conductor 6 and movable disk 18 are inseparable from the hollow groove 21 but can undergo a certain degree of relative movement, thereby accommodating the displacement of terminal 3 during tapered alignment in terminal groove 9. Compensation; specifically, a circular movable cavity for the movable plate 18 to fit and accommodate can be formed in the hollow groove 21. The groove opening or inner wall of the hollow groove 21 is provided with a limiting step or limiting edge. The movable plate 18 is located inside the limiting step or limiting edge, so that the movable plate 18 cannot axially detach from the hollow groove 21. At the same time, the movable plate 18 can slide or rotate a small range relative to the terminal 3 within the range defined by the hollow groove 21. This movement is not free loosening, but is used to provide limited compensation degree of freedom when the terminal 3 is guided by the conical positioning surface of the terminal groove 9.

[0053] To ensure stable conductivity between conductor 6 and terminal 3, the movable disk 18 is in close contact with the inner wall of the hollow groove 21, exhibiting damping characteristics. The upper or lower surface of the movable disk 18 can form surface contact with the corresponding conductive contact surface inside the hollow groove 21. Furthermore, the contact surfaces of the movable disk 18 and the hollow groove 21 can be tin-plated, silver-plated, or polished smooth conductive contact surfaces to reduce contact resistance. The groove opening limiting structure of the hollow groove 21 constrains the movement range of the movable disk 18 and reduces the possibility of epoxy resin casting material entering between the main contact surfaces of the movable disk 18 and the hollow groove 21. Thus, the movable compensation component has both conductive connection and error compensation functions.

[0054] It should be noted that a conical groove is provided at the bottom of terminal 3, which is a pressure-gathering cavity. In this embodiment, the pressure-gathering cavity is conical and flared, and is connected to the molding cavity, so that the epoxy resin casting material can enter the pressure-gathering cavity or act on the inner wall of the pressure-gathering cavity after entering the molding cavity. During casting, the epoxy resin casting material generates pressure on the inner wall of the pressure-gathering cavity. This pressure has an auxiliary force that makes terminal 3 adhere to terminal groove 9. By aggregating the casting material pressure, the adhesion pressure between terminal 3 and the inner wall of terminal groove 9 is increased, thereby increasing the sealing performance and reducing or even avoiding glue overflow at terminal groove 9 during subsequent casting. Furthermore, as the casting material pressure increases, the conical adhesion tendency between terminal 3 and terminal groove 9 is strengthened, thereby forming a tightening effect assisted by the casting pressure. This casting material pressure is not the only driving force for the initial upward movement and centering of terminal 3, but is used to further improve the adhesion stability and sealing performance after terminal 3 has been pushed up by the push assembly and adhered to terminal groove 9.

[0055] Thus, the terminal 3 and the terminal slot 9 achieve multiple mating effects through their mutually adaptable conical structures. On the one hand, during the vertical upward movement, the terminal 3 can automatically enter the center position of the terminal slot 9 through the conical surface, reducing hard contact and jamming between the terminal 3 and the terminal slot 9 caused by terminal processing errors, conductor 6 connection errors, and initial positioning errors of the insulating seat 4. On the other hand, after the terminal 3 enters the terminal slot 9, it can form a continuous fit through the conical surface, which, combined with the pressure of the casting material, improves the sealing effect around the terminal slot 9. Furthermore, the lower cross-sectional area of ​​the terminal 3 is larger than that of the upper cross-sectional area. After casting and curing, the lower end of the terminal 3 is covered by the epoxy resin casting body and forms an inverted anchoring structure, thereby improving the pull-out resistance between the terminal 3 and the epoxy resin casting body.

[0056] After casting, the upper end of terminal 3 protrudes from the top of the molded epoxy resin, while the lower end is located in the molded epoxy resin. The frustoconical lower end of terminal 3 forms a tenon-like inverted anchoring structure with the cured epoxy resin casting. Since terminal 3 is usually provided with bolt holes, it may be subjected to tensile force, torque or vibration load when it is subsequently bolted to external busbars, copper busbars or connectors. This inverted anchoring structure can reduce the risk of terminal 3 loosening, being pulled out or changing its posture relative to the epoxy resin casting.

[0057] The aforementioned push assembly includes a mounting cavity 13 located on the inner side of the lower end of the fixed mold 1. A wedge-shaped drive body 7 is movably disposed on the lower inner side of the mounting cavity 13 along the displacement direction of the moving mold 2. Initially, the end of the wedge-shaped drive body 7 closest to the moving mold 2 protrudes from the side wall of the fixed mold 1. When the moving mold 2 moves closer to the fixed mold 1, it can push the wedge-shaped drive body 7 to move. A wedge-shaped force-bearing body 11 is vertically movably disposed on the upper inner side of the mounting cavity 13, which cooperates with the inclined surface of the wedge-shaped drive body 7. A guide rail is provided at the inclined surface. The wedge-shaped drive body 7 and the wedge-shaped force-bearing body 11 form a sliding guide cooperation through the guide rail to ensure that the lateral displacement of the wedge-shaped drive body 7 can be stably converted into the vertical displacement of the wedge-shaped force-bearing body 11. When the wedge-shaped drive body 7 is pushed by the moving mold 2, the wedge-shaped force-bearing body 11 can be raised through the inclined surface cooperation. When the wedge-shaped drive body 7 is reset outward or pulled outward, the wedge-shaped force-bearing body 11 can be lowered with the cooperation of the inclined surface and the guide rail.

[0058] An active push column 12 is vertically arranged on the wedge-shaped force-bearing body 11, and a driven push column 10 is arranged at the bottom of the conductor 6, extending to the bottom of the insulating base 4 and corresponding to the active push column 12. The driven push column 10 is movably connected to the insulating base 4. When the wedge-shaped force-bearing body 11 rises, the driven push column 10 can be pushed upward by the active push column 12, thereby driving the conductor 6 and the terminal 3 to rise as a whole, and causing the frustum-shaped positioning part of the terminal 3 to enter the terminal slot 9 to complete the centering. The driven push column 10 is connected to the conductor 6 as a whole or fixedly connected, so that the upward pushing force of the active push column 12 can be transmitted to the conductor 6 and the terminal 3. The driven push column 10 is made of insulating material to avoid affecting the use of the current transformer in the future.

[0059] To further enhance the stability and sealing of terminal 3 and terminal slot 9, an active pusher 12 is vertically and movably connected to a wedge-shaped force-bearing body 11. The active pusher 12 is configured as a T-shaped pin structure, and a first elastic structure 19 is provided on the outer side of the upper end of the active pusher 12. The first elastic structure 19 is preferably a compression spring sleeved on the outside of the active pusher 12. When the wedge-shaped force-bearing body 11 rises to its limit height, terminal 3 and terminal slot 9 are in a tight fit. At this time, the first elastic structure 19 is in a contracted state, and the first elastic structure 19 provides a continuous pre-tightening force to terminal 3. This further improves the sealing and stability of terminal 3 and terminal slot 9 during casting, and also avoids damage caused by excessive rigid push, thus providing a buffer protection effect. In other words, the active pusher 12 does not rigidly press terminal 3 into terminal slot 9, but rather forms an elastic upward push through the first elastic structure 19, so that terminal 3 remains in contact under the action of the conical positioning surface of terminal slot 9 and allows for slight compensation, thereby taking into account centering, pre-tightening, and damage prevention.

[0060] Furthermore, the premise for the aforementioned terminal 3 and terminal slot 9 to form a fit is that the insulating base 4, coil assembly 5, conductor 6, and terminal 3 are pre-fixed in the molding cavity of the mold assembly. If the initial position deviation of the whole in the molding cavity is too large, it will be difficult to achieve a smooth fit between terminal 3 and terminal slot 9. Therefore, a pre-positioning component is provided in the molding cavity. The pre-positioning component can use conventional positioning structures such as positioning pins, positioning holes, positioning protrusions, positioning recesses, or limiting steps to achieve basic positioning. This embodiment takes the insertion positioning of positioning pin 8 and positioning slot 16 as an example for explanation, but it should not be understood that the pre-positioning component is limited to this one form.

[0061] Specifically, a locating pin 8 protruding upwards is provided on the bottom wall of the inner cavity of the fixed mold 1, and a locating groove 16 that cooperates with the locating pin 8 is provided at the bottom of the insulating seat 4. Initially, the insulating seat 4, the coil assembly 5 and the terminal 3 are placed in the inner cavity of the fixed mold 1, so that the locating pin 8 and the locating groove 16 are inserted and positioned. At this time, the terminal 3 can correspond to the terminal groove 9 at the upper end of the fixed mold 1. When the moving mold 2 approaches the fixed mold 1 to close the mold, the terminal groove 9 on the fixed mold 1 first corresponds to the terminal 3. Then, under the action of the push assembly, the terminal 3 rises and forms a preliminary alignment with the inner wall of the terminal groove 9 on the fixed mold 1. When the moving mold 2 continues to approach the fixed mold 1 and completes the mold closing, the terminal groove 9 on the fixed mold 1 and the moving mold 2 together limit the final position of the terminal 3, so that the exposed part of the terminal 3 completes the final fit with the terminal groove 9 in the mold closing state.

[0062] To prevent the insulating seat 4 from separating from the bottom wall of the inner cavity of the fixed mold 1 when the active push column 12 pushes the driven push column 10, and to prevent the transformer assembly from tilting or skewing, the insulating seat 4 is locked by a locking assembly before the active push column 12 pushes the driven push column 10. The purpose of this locking action is to first reliably press the insulating seat 4 against the bottom wall of the inner cavity of the fixed mold 1, so that the insulating seat 4 and the coil assembly 5 form a stable reaction force reference. Subsequently, when the active push column 12 pushes the terminal 3 up, the reaction force generated by the terminal 3 will not cause the insulating seat 4 and the coil assembly 5 to float up or disengage from the positioning pin 8, thereby ensuring that the compensation displacement of the terminal 3 mainly occurs at the movable compensation assembly between the terminal 3 and the conductor 6.

[0063] In a preferred embodiment, the locking assembly includes a push pin 17 mounted on the wedge-shaped force-bearing body 11 and corresponding to the positioning pin 8. The positioning pin 8 is a hollow structure, with the upper end of the positioning groove 16 being tapered and the lower end being cylindrical and adapted to the positioning pin 8. A locking cone 14 is vertically and movably connected to the inner side of the positioning pin 8. The upper end of the locking cone 14 is tapered, and an inclined guide rail or guide rod is provided on the upper sidewall of the locking cone 14. A locking block 15 corresponding to the locking cone 14 is movably connected to the inner sidewall of the upper sidewall of the positioning pin 8 along the radial direction of the positioning pin 8. The end of the locking block 15 away from the axis of the positioning pin 8 can extend to the outside of the positioning pin 8 and form an inclined surface fit with the inner wall of the tapered expansion section of the positioning groove 16. The end of the locking block 15 close to the axis of the positioning pin 8 is movable. The guide rail or guide rod connected to the locking cone 14 has a sliding fit with the upper conical surface of the locking cone 14; the push column 17 is used to push the locking cone 14 before the active push column 12 pushes the driven push column 10, so that the locking block 15 extends out of the inner wall of the pressing positioning groove 16, thereby increasing the stability between the insulating seat 4 and the inner wall of the fixed mold 1, avoiding separation, and reducing or even avoiding the epoxy resin casting material entering the gap between the insulating seat 4 and the inner wall of the fixed mold 1 during subsequent casting; wherein, when the locking block 15 is engaged with the inner wall of the conical expansion section of the positioning groove 16, the force applied by the locking block 15 to the inner wall of the positioning groove 16 has a component force that presses the insulating seat 4 toward the bottom wall of the inner cavity of the fixed mold 1, thereby realizing the downward locking of the insulating seat 4, rather than simply restricting the horizontal movement of the insulating seat 4.

[0064] In order to achieve the sequential action of locking the insulating seat 4 first and then pushing the terminal 3 upward, the initial contact position of the push post 17 and the locking cone 14 is higher than the initial contact position of the active push post 12 and the driven push post 10, or an initial gap is reserved between the active push post 12 and the driven push post 10, so that the first part of the upward stroke of the wedge-shaped force-bearing body 11 pushes the locking cone 14 upward through the push post 17 and drives the locking block 15 to extend. After the insulating seat 4 is locked, the wedge-shaped force-bearing body 11 continues to rise, and the active push post 12 contacts and pushes the driven push post 10 upward again. Through this sequential action, it can be avoided that the insulating seat 4 moves upward as a whole when the terminal 3 is pushed upward.

[0065] To accommodate the continued upward movement of the active pusher 12 to drive the driven pusher 10, the upper end of the pusher 17 and the inner side of the lower end of the locking cone 14 are movably connected. A second elastic structure 20 is provided between the bottom of the locking cone 14 and the top of the wedge-shaped force-bearing body 11. The second elastic structure 20 is preferably a compression spring sleeved on the outside of the pusher 17. When the locking cone 14 rises to its limit distance, the pusher 17 can continue to rise with the wedge-shaped force-bearing body 11 and compress the second elastic structure 20. At the same time, the elastic pre-tightening force of the second elastic structure 20 continues to act on the locking block 15 through the locking cone 14. The locking block 15 acts on the inner wall of the positioning groove 16, thereby ensuring the contact pressure between the insulating seat 4 and the bottom wall of the inner cavity of the fixed mold 1. The second elastic structure 20 can continue to provide elastic pre-tightening after the insulating seat 4 is locked, so that the locking block 15 will not release the pressure on the positioning groove 16 due to subsequent actions of the pusher assembly or minor vibrations during the pouring process.

[0066] Furthermore, to facilitate demolding of the final product from the fixed mold 1, the positioning pin 8 is vertically and movably connected to the bottom wall of the inner cavity of the fixed mold 1, with its lower end located in the mounting cavity 13. The push pin 17 is configured as a T-shaped structure, which is inseparable from the locking cone 14. After the fixed mold 1 separates from the moving mold 2, under the action of the second elastic structure 20, the first elastic structure 19, and the gravity of the wedge-shaped force-bearing body 11, the push pin 17 drives the wedge-shaped force-bearing body 11 to move downward, thereby causing the wedge-shaped driving body 7 to move outward and protrude from the side wall of the fixed mold 1, and can be pulled outward. The wedge-shaped drive body 7 drives the wedge-shaped force-bearing body 11 to continue moving downward. The wedge-shaped force-bearing body 11 drives the locking cone 14 and the positioning pin 8 to move downward as a whole through the push column 17, so that the upper end of the positioning pin 8 is disengaged from the positioning groove 16 and hidden, which facilitates the separation of the product from the bottom wall of the inner cavity of the fixed mold 1. During the downward movement of the locking cone 14, the locking block 15 is driven by the guide rail or guide rod of the locking cone 14 to retract towards the inside of the positioning pin 8, so that the locking block 15 is disengaged from the inner wall of the conical expansion section of the positioning groove 16, thereby releasing the locking state of the insulating seat 4.

[0067] It should be noted that before placing the current transformer assembly into the inner cavity of the fixed mold 1, the wedge-shaped drive body 7 can be pushed inward to make the positioning pin 8 protrude. The lower end of the positioning pin 8 can be limited by setting a flange or protrusion-like structure. After the positioning pin 8 protrudes, one end of the wedge-shaped drive body 7 is still protruding, and it is subsequently pushed by the moving mold 2 when the mold is closed. In this state, the positioning pin 8 is used for the positioning groove 16 of the insulating seat 4 to fit into, realizing the initial positioning of the current transformer assembly when it is placed into the fixed mold 1. After the moving mold 2 completes the mold closing drive, the locking component and the pushing component act in sequence, so that the insulating seat 4 is locked and the terminal 3 is moved upward and centered.

[0068] Working principle

[0069] In use, the wedge-shaped drive body 7 is first positioned so that the positioning pin 8 protrudes from the bottom wall of the inner cavity of the fixed mold 1. Then, the current transformer assembly, consisting of the insulating seat 4, coil assembly 5, conductor 6 and terminal 3, is placed into the molding cavity of the fixed mold 1. The positioning groove 16 at the bottom of the insulating seat 4 is fitted onto the positioning pin 8. The positioning pin 8 and the positioning groove 16 complete the initial positioning of the current transformer assembly in the fixed mold 1. At this time, the terminal 3 roughly corresponds to the terminal groove 9 at the upper end of the fixed mold 1. However, due to processing errors, connection errors between the terminal 3 and the conductor 6, or initial positioning errors of the current transformer assembly, there may still be a small range of deviation between the terminal 3 and the terminal groove 9.

[0070] When the moving mold 2 moves to the fixed mold 1 to close the mold, the moving mold 2 pushes the wedge-shaped drive body 7 to move into the mounting cavity 13. The wedge-shaped drive body 7 pushes the wedge-shaped force-bearing body 11 to rise through the cooperation of the inclined surface and the guide rail. During the first part of the upward stroke of the wedge-shaped force-bearing body 11, the push column 17 first pushes the locking cone 14 to rise. The locking cone 14 drives the locking block 15 to extend radially along the positioning pin 8. The outer end of the locking block 15 contacts the inner wall of the tapered expansion section at the upper end of the positioning groove 16 and generates an inclined surface pressing effect, so that the insulating seat 4 is pressed downward on the inner cavity bottom wall of the fixed mold 1, thereby forming a stable reaction force reference between the coil assembly 5 and the insulating seat 4.

[0071] After the insulating seat 4 is locked, the wedge-shaped force-bearing body 11 continues to rise. The active push column 12 pushes the driven push column 10 upward through the first elastic structure 19. The driven push column 10 drives the conductor 6 and the terminal 3 to move upward. During the upward movement of the terminal 3, the conical inclined surface of the terminal 3 enters the conical positioning surface of the terminal slot 9. If there is a small deviation between the terminal 3 and the terminal slot 9, the conical positioning surface of the terminal slot 9 will guide the terminal 3. The terminal 3 will slide or rotate a small range relative to the conductor 6 through the restricted movement between the hollow slot 21 and the movable disk 18, so that the terminal 3 gradually corrects its deviation and is aligned with the terminal slot 9.

[0072] After terminal 3 enters terminal slot 9, the first elastic structure 19 is in a compressed state, and continuously applies an elastic upward pushing force to terminal 3 through active pushing column 12, driven pushing column 10 and conductor 6, so that the conical inclined surface of terminal 3 keeps in contact with the conical positioning surface of terminal slot 9. Since the upward pushing force is an elastic force rather than a rigid pressing force, it can prevent terminal 3 from being damaged due to excessive compression, and at the same time, it can compensate for the slight size difference between terminal 3 and terminal slot 9, and improve the adhesive sealing effect at terminal slot 9.

[0073] After the mold is closed, the mold assembly is sent into the vacuum casting equipment. The epoxy resin casting material enters the molding cavity and covers the coil assembly 5, the insulating seat 4, the conductor 6 and the lower area of ​​the terminal 3. When the casting material rises and enters the pressure chamber at the bottom of the terminal 3 or acts on the inner wall of the pressure chamber, it generates an auxiliary pressure on the terminal 3 to adhere to the terminal groove 9, making the terminal 3 fit more tightly with the conical surface of the terminal groove 9, thereby further improving the stability of the terminal and the sealing of the periphery of the terminal groove 9 during the casting process.

[0074] After the epoxy resin casting material cures, it forms an epoxy resin casting body. The upper end of terminal 3 is exposed on the top of the casting body for subsequent bolt connection. The large-section frustum portion of the lower end of terminal 3 is covered by the epoxy resin casting body, forming an inverted anchoring structure. When terminal 3 is subsequently connected to an external busbar, copper busbar or connector and is subjected to tension, torque or vibration, this inverted anchoring structure can improve the pull-out resistance and loosening resistance of terminal 3 relative to the epoxy resin casting body.

[0075] During demolding, the moving mold 2 separates from the fixed mold 1. The wedge-shaped drive body 7 drives the wedge-shaped force-bearing body 11 to descend. The active pusher 12 releases the elastic push on the driven pusher 10. The pusher 17 gradually resets and drives the locking cone 14 to descend. The locking block 15 retracts with the locking cone 14 and releases the pressure on the positioning groove 16. After the wedge-shaped drive body 7 protrudes, it can be manually or by using tools to pull or reset the wedge-shaped drive body 7. As the wedge-shaped force-bearing body 11 continues to move downward, the positioning pin 8 can exit from the positioning groove 16 or be hidden below the inner cavity bottom wall of the fixed mold 1, thus facilitating the removal of the cured transformer assembly from the fixed mold 1.

[0076] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A casting and positioning device for preventing offset of transformer coils and terminals in a ring main unit, characterized in that, It includes a current transformer assembly and a mold assembly for accommodating the current transformer assembly. The mold assembly includes a fixed mold (1), a moving mold (2) corresponding to the fixed mold (1), and terminal slots (9) disposed on the fixed mold (1) and the moving mold (2). The current transformer assembly includes an insulating base (4), a coil assembly (5) mounted on the insulating base (4), a conductor (6) vertically and movably connected to the insulating base (4), and a terminal (3) connected to the upper end of the conductor (6). The four sides of the terminal (3) are provided with tapered slopes, the inner wall of the terminal groove (9) is provided with a tapered positioning surface that matches the tapered slope of the terminal (3), and the bottom of the terminal (3) is provided with a pressing cavity that communicates with the forming cavity. An active compensation component is provided between the terminal (3) and the conductor (6). The active compensation component is used to enable the terminal (3) to generate a compensation activity relative to the conductor (6) within a predetermined range while maintaining an electrical connection with the conductor (6). The fixed mold (1) is provided with a push assembly at its lower end. The push assembly is used to push the conductor (6) and the terminal (3) to rise in the vertical direction according to the closing action of the moving mold (2), so that the terminal (3) can be guided and centered by cooperating with the tapered positioning surface of the terminal slot (9) through the tapered inclined surface. A prepositioning component is provided between the inner cavity bottom wall of the fixed mold (1) and the insulating seat (4). A locking component is also provided at the lower end of the fixed mold (1). The locking component is used to press the insulating seat (4) onto the inner cavity bottom wall of the fixed mold (1) before the push component pushes the conductor (6) and terminal (3) up.

2. The anti-offset casting and positioning device for transformer coils and terminals in a ring main unit according to claim 1, characterized in that, The top of the terminal (3) is a rectangular exposed wiring part, and the cross-sectional area of ​​the lower end of the terminal (3) is larger than the cross-sectional area of ​​the upper end of the terminal (3), so that the terminal (3) forms a frustum-shaped structure with a smaller top and a larger bottom. The pressure chamber is a conical flared groove formed at the bottom of the terminal (3). The pressure chamber is used to withstand the pressure of the epoxy resin casting material after it enters, so that the terminal (3) tends to abut against the conical positioning surface of the terminal groove (9).

3. The anti-offset casting positioning device for transformer coils and terminals in a ring main unit according to claim 1, characterized in that, The active compensation component includes a hollow groove (21) disposed at the bottom of the terminal (3) and an active disk (18) disposed at the top of the conductor (6).

4. The anti-offset casting and positioning device for the transformer coil and terminal of the ring main unit according to claim 3, characterized in that, The active compensation component also includes a limiting step set at the opening of the hollow groove (21), and the active plate (18) is located inside the limiting step, so that the active plate (18) can slide relative to the terminal (3) within the range defined by the hollow groove (21).

5. The anti-offset casting positioning device for transformer coils and terminals in a ring main unit according to claim 1, characterized in that, The push assembly includes an installation cavity (13) disposed on the inner side of the lower end of the fixed mold (1), a wedge-shaped drive body (7) movably disposed on the lower end of the inner side of the installation cavity (13) along the displacement direction of the moving mold (2), a wedge-shaped force-bearing body (11) vertically movably disposed on the upper end of the inner side of the installation cavity (13), an active push column (12) disposed on the wedge-shaped force-bearing body (11), and a driven push column (10) disposed at the bottom of the conductor (6). The end of the wedge-shaped drive body (7) near the moving mold (2) can protrude from the side wall of the fixed mold (1), and the moving mold (2) can push the wedge-shaped drive body (7) to move when it closes to the fixed mold (1); The driven push column (10) extends downward to the bottom of the insulating seat (4) and is correspondingly arranged with the active push column (12); The wedge-shaped drive body (7) is engaged with the inclined surface of the wedge-shaped force-bearing body (11). When the wedge-shaped drive body (7) is pushed, it can drive the wedge-shaped force-bearing body (11) to rise, and cause the active push column (12) to push the driven push column (10) to rise. The driven push column (10) drives the conductor (6) and the terminal (3) to rise.

6. The anti-offset casting positioning device for transformer coils and terminals in a ring main unit according to claim 5, characterized in that, The active jacking column (12) is vertically and movably connected to the wedge-shaped force-bearing body (11), and a first elastic structure (19) is provided on the outer side of the upper end of the active jacking column (12). The first elastic structure (19) is used to generate an elastic pushing force when the driven pushing column (10) is pushed on the active pushing column (12).

7. The anti-offset casting positioning device for transformer coils and terminals in a ring main unit according to claim 5, characterized in that, The pre-positioning component includes a positioning pin (8) disposed on the bottom wall of the inner cavity of the fixed mold (1) and a positioning groove (16) disposed on the bottom of the insulating seat (4). The positioning pin (8) can be inserted into the positioning groove (16) to initially position the insulating seat (4).

8. The anti-offset casting positioning device for transformer coils and terminals in a ring main unit according to claim 7, characterized in that, The locking assembly includes a pusher (17) installed on the wedge-shaped force-bearing body (11) and corresponding to the positioning pin (8), a locking cone (14) vertically and movably disposed inside the positioning pin (8), and a locking block (15) radially and movably disposed inside the upper side wall of the positioning pin (8). The lower end of the positioning groove (16) is a cylindrical section that fits the positioning pin (8), and the upper end of the positioning groove (16) is a conical expansion section. The pusher (17) is used to push the locking cone (14) upward. The upper end of the locking cone (14) is conical. The locking block (15) is in sliding fit with the locking cone (14) at one end near the axis of the positioning pin (8). The locking block (15) can extend to the outside of the positioning pin (8) and fit with the inclined surface of the inner wall of the conical expansion section of the positioning groove (16) to press the insulating seat (4) against the inner cavity bottom wall of the fixed mold (1).

9. The anti-offset casting positioning device for transformer coils and terminals in a ring main unit according to claim 8, characterized in that, The push column (17) is movably connected to the locking cone (14), and a second elastic structure (20) is provided between the bottom of the locking cone (14) and the top of the wedge-shaped force-bearing body (11). When the wedge-shaped force-bearing body (11) rises, the push column (17) first pushes the locking cone (14) to rise and drives the locking block (15) to extend, and then the active push column (12) pushes the driven push column (10) to rise.

10. The anti-offset casting positioning device for transformer coils and terminals in a ring main unit according to claim 8, characterized in that, The positioning pin (8) is vertically and movably connected to the bottom wall of the inner cavity of the fixed mold (1); The pusher column (17) has a T-shaped structure and is inseparably connected to the locking cone (14); When the wedge-shaped force-bearing body (11) moves downward, it can drive the locking cone (14) to move downward through the push column (17), causing the locking block (15) to retract and release the pressure on the positioning groove (16). When the wedge-shaped force-bearing body (11) continues to move downward, it can drive the positioning pin (8) to exit from the positioning groove (16) or hide below the bottom wall of the forming cavity of the fixed mold (1) through the push column (17).

Images