Inner and outer double-coil structure

Abstract

The utility model belongs to the technical field of transformer manufacturing, and relates to an inner and outer double-coil structure, which comprises an outer-layer coil and an inner-layer coil sleeved at the inner central position of the outer-layer coil, the inner-layer coil comprises a coil P4 and a coil P3, the outer-layer coil comprises a coil P2 and a coil P1, the coils P1, P2, P3 and P4 are respectively formed by uninterruptedly winding leads, and the leads are respectively wound by the leads. The wires at the lower ends are respectively bent into U-shaped connecting structures, and the wires at the upper ends are respectively bent to lead out upper outgoing heads of the coils; the tops of the coils P2, P1, P4 and P3 are respectively provided with an upper end ring used for flattening the top ends of the coils, the upper end rings are provided with notches, and the bottoms of the coils P2, P1, P4 and P3 are respectively provided with a plurality of lower cushion blocks which are evenly distributed in the circumferential direction and used for flattening the bottom ends of the coils. According to the utility model, the welding-spot-free winding of the multi-layer coil is realized, the process is simple, the cost is low, the winding efficiency is high, and the anti-short-circuit capability of the coil is enhanced.

Description

Technical Field

[0001] This utility model belongs to the field of transformer manufacturing technology, specifically relating to an inner and outer double coil structure. Background Technology

[0002] With the rapid development of the power industry, small distribution transformers and switching reactors, as core components of the power system, have been subject to higher requirements in terms of coil structure compactness, mechanical strength, and electrical performance.

[0003] In existing multi-layer coil winding methods, the winding process generally involves segmented winding followed by welding the ends of the conductors to connect the inner and outer coil layers. Electrical connections between the inner and outer coil layers typically require lead-out copper strips followed by welding or riveting, resulting in complex coil end structures and increased redundant solder joints. Furthermore, the welding process has significant drawbacks: solder joints are prone to cracking due to mechanical stress or temperature rise, leading to increased local coil resistance or even open-circuit faults. In addition, the welding process relies on manual operation, resulting in high process complexity and difficulty in ensuring solder joint consistency. This is especially problematic in miniaturized environments where spatial constraints further increase the difficulty and cost of welding. Research indicates that under transformer short-circuit impacts or frequent start-stop conditions, solder joints are susceptible to fatigue fracture due to electromagnetic forces or thermal cycling stress, becoming high-risk weak points for equipment failure and severely impacting equipment lifespan and safety.

[0004] Currently, research on multilayer coil winding technology focuses primarily on material optimization or insulation design, with insufficient attention paid to innovation in coil winding structures. Furthermore, in traditional processes, rewinding multilayer coils requires repeated adjustments to the conductor paths, which is not only inefficient but also prone to inter-turn insulation damage due to human error.

[0005] To address the aforementioned technical challenges, how to achieve solderless integrated winding of multi-layer coils within a limited space, while simultaneously improving the coil's short-circuit withstand capability and production efficiency, has become a pressing technical hurdle to overcome in this field. Therefore, it is imperative to design a novel multi-layer coil winding structure and winding process method that fundamentally eliminates the risk of wire solder joints through topology optimization, simplifies the production process, and meets the stringent space utilization requirements of miniaturized equipment. Summary of the Invention

[0006] To solve the above-mentioned technical problems, this utility model provides an inner and outer dual-coil structure. The technical solution adopted by this utility model is as follows:

[0007] An inner and outer double-coil structure includes an outer coil and an inner coil nested inside the center of the outer coil. The inner coil includes coil P4 and coil P3, which are formed by continuously winding several wires without interruption. The lower ends of the wires of coils P4 and P3 are bent into a U-shaped connection structure, and the upper ends of the wires of coils P4 and P3 are bent and lead out of the upper part of the coil. The outer coil includes coil P2 and coil P1, which are formed by continuously winding several wires without interruption. The lower ends of the wires of coils P2 and P1 are bent into a U-shaped connection structure, and the upper ends of the wires of coils P2 and P1 are bent and lead out of the upper part of the coil.

[0008] Preferably, coils P2, P1, P4 and P3 are each provided with an upper end ring for flattening the top of the coil, and the upper end ring is provided with a notch.

[0009] Preferably, coils P2, P1, P4 and P3 are each provided with a number of circumferentially evenly distributed lower pads for flattening the bottom of the coils.

[0010] Preferably, coils P2 and P4 are wound with the conductor in the right direction, and coils P3 and P1 are wound with the conductor in the left direction.

[0011] Preferably, the bottom of the upper end ring is a spiral structure that matches the top of the coil, the upper part of the upper end ring is a horizontal structure, the end of the upper end ring is processed into a chamfered structure, and the thickness of the upper end ring is the same as the thickness of the single-layer coil.

[0012] Preferably, the upper end ring is made of sulfate paper.

[0013] Preferably, the top of the lower pad is a sloping structure that matches the bottom of the coil, the bottom of the lower pad is a horizontal structure, the thickness of the lower pad is the same as the thickness of the single-layer coil, the lower pad is placed on both sides of the lower end of the coil, and a full circle of PET tape is tied around the outer side of the circumference formed by the lower pad.

[0014] Preferably, the material of the lower pad is laminated cardboard.

[0015] Preferably, the outer coil is sleeved on the outer periphery of the insulating paper tube outside the iron core column. Coils P2 and P4 are close to the iron core column. Several circumferentially distributed support strips are arranged between the insulating paper tube outside the iron core column and coil P2. Several circumferentially distributed support strips are arranged on the outer periphery of coil P1. Several paper tubes are sleeved between coil P4 and coil P2, between coil P4 and coil P3, and between coil P3 and coil P1. Several circumferentially distributed support strips are arranged between adjacent paper tubes and between paper tubes and coils. Casein glue is applied to the side of the support strips adjacent to the paper tubes.

[0016] Preferably, the bends in the wires are wrapped with crepe paper.

[0017] The beneficial effects of this utility model are:

[0018] Traditional multi-layer coils connect the innermost and outermost coils by soldering, resulting in hundreds of solder joints. This method is not only time-consuming and labor-intensive, but also prone to cracking at the solder joints due to coil compression or prolonged operation, posing a short-circuit risk. The double-coil structure proposed in this invention saves space and enables solder-free winding of multi-layer coils, significantly reducing the risk of solder joint cracking during coil compression and operation. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are some specific embodiments of this utility model. For those skilled in the art, other drawings that fall within the scope of protection of this application can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a cross-sectional schematic diagram of one side of the inner and outer double coils in an embodiment of this utility model;

[0021] Figure 2 This is a bottom view of the inner and outer double coils according to an embodiment of the present invention, wherein 2-1 is a bottom view of coils P4-P3. Figure 2-2 This is a bottom view of coils P2-P1;

[0022] Figure 3 This is a schematic diagram of the unfolded coils P2 and P4 according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the unfolded coils P1 and P3 according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the upper end ring of an embodiment of the present utility model, wherein 5-1 is a front view of the upper end ring and 5-2 is a top view of the upper end ring;

[0025] Figure 6 This is a structural schematic diagram of the lower pad block according to an embodiment of the present utility model, wherein 6-1 is a bottom view of the lower pad block being placed, and 6-2 is a sectional view of 6-1 along the AA direction.

[0026] Figure 7 This is a schematic diagram of the winding direction and wiring principle of the inner and outer double coils in this embodiment of the utility model;

[0027] Figure 8This is a schematic diagram of the wire used for pre-reserving coil P1 on the adjustable winding mold according to an embodiment of the present invention;

[0028] In the diagram, 21 is the support bar, 22 is the paper tube, 23 is the crepe paper, 24 is the upper end ring, 25 is the lower pad, 26 is the outer insulating paper tube of the iron core column, 27 is the adjustable winding mold, and 28 is the PET tape. Detailed Implementation

[0029] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0030] like Figure 1-8 As shown, an inner and outer double-coil structure includes an outer coil and an inner coil nested inside the center of the outer coil. The inner coil includes coil P4 and coil P3, which are continuously wound with six wires. The lower ends of the wires of coils P4 and P3 are bent into a U-shaped connection structure to achieve a series connection between them. The upper ends of the wires of coils P4 and P3 are bent and lead out to the upper part of the coil. The upper and lower ends of the bent wires of coils P4 and P3 are respectively wrapped with heat-resistant crepe paper 23. The crepe paper 23 is used to improve the heat resistance of the coils. The insulation and mechanical strength of coils P4 and P3 are specified. The outer coils include coils P2 and P1, which are continuously wound with six wires. The lower wires of coils P2 and P1 are bent into a U-shaped connection to achieve series connection. The upper wires of coils P2 and P1 are bent and lead out at the top of the coils. The bent ends of the upper and lower wires of coils P2 and P1 are wrapped with heat-resistant crepe paper 23 to improve the insulation and mechanical strength of coils P2 and P1. Coils P2 and P4 are wound in a right-hand direction, while coils P3 and P1 are wound in a left-hand direction. Figure 3 , Figure 4 This design reflects the different winding directions of the conductors; the inner and outer layers are wound in opposite directions, ensuring that the magnetic flux of the inner and outer series conductors is aligned, thus balancing the electromagnetic force. In coils P2 and P1, and coils P4 and P3, the six conductors form six U-shaped connection structures at the lower end of the coils. These six U-shaped connection structures are evenly distributed along the circumference of the coils, eliminating the need for welding the conductors. The inner and outer double-coil structure improves the space utilization of transformers or reactors, enabling the winding of more layers of coils within a limited space.

[0031] The outer coil is sleeved on the outer periphery of the insulating paper tube 26 outside the iron core post. Coil P2 is close to the iron core post. Several vertically oriented support bars 21 are evenly distributed circumferentially between the insulating paper tube 26 outside the iron core post and coil P2. Several vertically oriented support bars 21 are evenly distributed circumferentially around the outer periphery of coil P1. The outermost support bar 21 is also surrounded by a paper tube for the coil assembly process. This part is... Figure 1 Not shown in the diagram; the inner coil is nested inside the center of the outer coil, with coil P4 close to the iron core post. Several paper tubes 22 are placed at the center between coil P4 and coil P3. Several paper tubes 22 are nested between the outer and inner coils (between coil P4 and coil P2, and between coil P3 and coil P1). Several vertically oriented support bars 21 are evenly distributed around the circumference between adjacent paper tubes 22, between paper tubes 22 and the outer coil, and between paper tubes 22 and the inner coil. By setting support bars 21 and paper tubes 22 between each layer of coils, the overall heat dissipation effect and insulation margin of the coil are improved. A small amount of casein glue is applied to the side of the support bar 21 adjacent to the paper tube 22 for bonding and fixing. After the coil, support bars 21 and paper tubes 22 are pressed together, they form a strong integrated coil structure by means of tension.

[0032] Coils P2, P1, P4, and P3 each have an upper end ring 24 on their upper parts. The upper end ring 24 is used to flatten the upper end of the coil. The upper end ring 24 is preferably made of sulfate paper pulp. The bottom of the upper end ring 24 has a spiral structure that matches the top of the coil, while the upper part of the upper end ring 24 has a horizontal structure. The ends of the upper end ring 24 are chamfered to prevent damage to the conductors. The upper end ring 24 has a notch. After the multi-layer coil is wound and pressed tightly together, the upper end ring 24 is placed directly on top of the coil. The upper end of the coil extends out from the notch in the upper end ring 24. The thickness of the upper end ring 24 is the same as the thickness of a single-layer coil.

[0033] Each of coils P2, P1, P4, and P3 has several circumferentially evenly distributed lower pads 25 at its bottom. These lower pads 25 are used to flatten the bottom of the coils. The lower pads 25 are preferably made of laminated cardboard. The top of each lower pad 25 has a sloping structure that matches the bottom of the coil, while the bottom is horizontal. The thickness of each lower pad 25 is the same as the thickness of a single coil layer. The lower pads 25 are placed on both sides of the bottom protrusion of each coil layer, and a PET strap 28 is used to secure the outer circumference of the lower pads 25.

[0034] illustrate: Figure 1 The lower horizontal solid line is to indicate that coil P2 and coil P1, as well as coil P4 and coil P3, are connected in series through a U-shaped connection structure. Figure 1 The upper horizontal solid lines in the diagram represent the upper protrusions; they do not represent actual cross-sectional structural lines. The number of wires used for winding the coil needs to be flexibly selected based on the transformer's design requirements.

[0035] The aforementioned method for winding an inner and outer double coil structure includes the following steps:

[0036] First, based on the circumference and number of turns of the outermost coil P1, calculate and reserve the total length of wire required for coil P1 in advance.

[0037] Several support strips 21 are evenly distributed around the outer periphery of the insulating paper tube 26 on the outer side of the iron core column. A small amount of casein glue is applied to the side of the support strips 21 adjacent to the insulating paper tube 26 on the outer side of the iron core column for bonding and fixing. The coil P2 is wound from top to bottom in a right-hand descending layer around the insulating paper tube 26 and the support strips 21 on the outer side of the iron core column. After the coil P2 is wound, the remaining wires used to wind the coil P1 are wound one by one onto the adjustable winding mold 27. The adjustable winding mold 27 is an existing product. The adjustable part means that the diameter of the cylinder of the winding mold can be adjusted. It needs to be used with the winding machine to roll the wires onto the adjustable winding mold 27.

[0038] Place support strip 21-paper tube 22-support strip 21-paper tube 22-support strip 21 in sequence from the inside to the outside of coil P2. Apply a small amount of casein glue to the side of support strip 21 adjacent to paper tube 22 for bonding and fixing. Wind coil P4 around coil P2 and the outermost support strip 21 from top to bottom in a right-hand descending layer.

[0039] After coil P4 is wound, six lower pads 25 are placed at the lower end of coil P4 to flatten the lower end of coil P4. The lower pads 25 are placed on both sides of the lower end of coil P4. A PET tape 28 is tied around the outside of the circle formed by the six lower pads 25 to fix the lower pads 25. The lower end of the wire of coil P4 and the lower end of the wire of coil P3 are bent into a U-shaped connection structure. Crepe paper 23 is wrapped around the outer periphery of the wire at the bending position. Support strip 21-paper tube 22-support strip 21-paper tube 22-support strip 21 are placed in sequence from the inside to the outside of coil P4. A small amount of casein glue is applied to the side of support strip 21 adjacent to paper tube 22 for bonding and fixing. Coil P3 is wound from bottom to top in a left-to-upward layer around coil P4 and the outermost support strip 21. Six lower pads 25 are also placed at the lower end of coil P3 to flatten the lower end of coil P3.

[0040] After coil P3 is wound, the wire used for winding coil P1 on the adjustable winding mold 27 is rewound onto the pay-off frame. Six lower pads 25 are placed at the lower end of coil P2 to flatten the lower end of coil P2. The lower pads 25 are placed on both sides of the lower end of coil P2. A PET tape 28 is tied around the outside of the circumference formed by the six lower pads 25 to fix the lower pads 25. The lower ends of the wires of coil P2 and coil P1 are bent into U-shapes. The connection structure is constructed, and crepe paper 23 is wrapped around the outer periphery of the wire at the bending position. Support strip 21-paper tube 22-support strip 21-paper tube 22-support strip 21 are placed sequentially from the inside to the outside of the coil P3. A small amount of casein glue is applied to the side of the support strip 21 adjacent to the paper tube 22 for bonding and fixing. The coil P1 is wound from bottom to top in a left-to-upward layer around the coil P3 and the outermost support strip 21. Six lower pads 25 are also placed at the lower end of the coil P1 to flatten the lower end of the coil P1.

[0041] After coil P1 is wound, upper end rings 24 are placed on the top of coils P2, P4, P3 and P1 respectively to flatten the top of the coils. The wires are bent and led out from the notch of the upper end rings 24. Crepe paper 23 is wrapped around the outer circumference of the wires at the bend position, thus completing the winding of the entire inner and outer double coil structure.

[0042] In this embodiment of the utility model, all technical features not described in detail are existing technologies or conventional technical means, and will not be repeated here.

[0043] Finally, it should be noted that the above embodiments are merely specific implementations of this utility model, used to illustrate the technical solution of this utility model, and not to limit it. The protection scope of this utility model is not limited thereto. Those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this utility model; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be covered within the protection scope of this utility model.

Claims

1. A double-coil structure, comprising an outer coil and an inner coil nested at the center of the outer coil, characterized in that, The inner coil includes coil P4 and coil P3, which are formed by continuously winding several wires without interruption. The lower ends of the wires of coils P4 and P3 are bent into a U-shaped connection structure, and the upper ends of the wires of coils P4 and P3 are bent and lead out of the upper part of the coil. The outer coil includes coil P2 and coil P1, which are formed by continuously winding several wires without interruption. The lower ends of the wires of coils P2 and P1 are bent into a U-shaped connection structure, and the upper ends of the wires of coils P2 and P1 are bent and lead out of the upper part of the coil.

2. The inner and outer double coil structure according to claim 1, characterized in that, The tops of coils P2, P1, P4 and P3 are respectively provided with upper end rings for flattening the top of the coils, and the upper end rings are provided with notches.

3. The inner and outer double coil structure according to claim 1, characterized in that, The bottom of coils P2, P1, P4 and P3 are each provided with several circumferentially evenly distributed lower pads for flattening the bottom of the coils.

4. The inner and outer double coil structure according to any one of claims 1-3, characterized in that, Coil P2 and coil P4 are wound with the conductor in the right direction, while coil P3 and coil P1 are wound with the conductor in the left direction.

5. The inner and outer double coil structure according to claim 2, characterized in that, The bottom of the upper end ring has a spiral structure that matches the top of the coil. The upper part of the upper end ring has a horizontal structure. The end of the upper end ring is chamfered. The thickness of the upper end ring is the same as that of the single-layer coil.

6. The inner and outer double coil structure according to claim 5, characterized in that, The upper end ring is made of sulfate paper.

7. The inner and outer double coil structure according to claim 3, characterized in that, The top of the lower pad is a sloping structure that matches the bottom of the coil, and the bottom of the lower pad is a horizontal structure. The thickness of the lower pad is the same as the thickness of a single coil layer. The lower pad is placed on both sides of the lower end of the coil, and a full circle of PET tape is tied around the outer side of the circumference formed by the lower pad.

8. The inner and outer double coil structure according to claim 7, characterized in that, The lower pad is made of laminated cardboard.

9. The inner and outer double coil structure according to claim 1, characterized in that, The outer coil is sleeved on the outer periphery of the insulating paper tube outside the iron core column. Coils P2 and P4 are close to the iron core column. Several circumferentially distributed support bars are set between the insulating paper tube outside the iron core column and coil P2. Several circumferentially distributed support bars are set on the outer periphery of coil P1. Several paper tubes are sleeved between coil P4 and coil P2, between coil P4 and coil P3, and between coil P3 and coil P1. Several circumferentially distributed support bars are set between adjacent paper tubes and between paper tubes and coils. Casein glue is applied to the side of the support bars adjacent to the paper tubes.

10. The inner and outer double coil structure according to claim 1, characterized in that, Wrap the bends in the wire with crease paper.

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