Enameled wire and motor stator

Abstract

The utility model belongs to the technical field of motors, and particularly relates to an enameled wire and a motor stator, the enameled wire comprises a wire core, an insulating layer wrapping the wire core, and a foaming coating capable of forming a foaming layer through foaming expansion, and the foaming coating covers the outer surface of the insulating layer; when the enameled wire provided by the utility model is applied to a motor stator, the foaming coating fills gaps among stator slots through the foaming expansion characteristic, the installation stability of the enameled wire is effectively enhanced, the movement phenomenon is inhibited, and the enameled wire has the advantages of low cost and easiness in installation.

Description

Technical Field

[0001] This utility model belongs to the field of motor technology, specifically relating to an enameled wire and a motor stator. Background Technology

[0002] The fixing technology of motor windings is one of the key factors affecting motor performance and service life. Enamelled wire is a component of motor windings, but during its assembly, there is a problem of cross-movement. In traditional processes, the slot wedge fixing method was widely used due to its ease of operation. This method involves inserting slot wedges made of phenolic laminate or epoxy resin into the slots of the iron core, using mechanical pressure to secure the enamelled wire. However, in practical applications, this method suffers from the problems of cumbersome manual insertion of slot wedges and low assembly efficiency.

[0003] To address the gap filling problem between enameled wire and the core slots, the impregnation varnish fixing method uses vacuum pressure impregnation (VPI) to penetrate the insulating varnish into the winding gaps, forming a cured adhesive structure. While this process improves the overall integrity of the windings, it faces several challenges: firstly, the vacuum pressure impregnation equipment requires a high-precision vacuum system and pressure control device, resulting in high equipment investment and maintenance costs; secondly, the curing cycle of the impregnating varnish is relatively long, limiting production efficiency. Therefore, this paper proposes an enameled wire to solve these problems. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide an enameled wire and a motor stator. When the enameled wire is applied to the motor stator, its foamed coating fills the gap between the stator slots through its foaming expansion characteristics, effectively enhancing the installation stability of the enameled wire and suppressing the phenomenon of cross-movement. At the same time, it also has the advantages of low cost and easy installation.

[0005] To achieve the above and other related objectives, this utility model provides an enameled wire, comprising:

[0006] wire core;

[0007] An insulating layer covers the outside of the wire core;

[0008] And a foamed coating capable of forming a foamed layer through foaming expansion, the foamed coating covering the outer surface of the insulating layer.

[0009] In one embodiment of the present invention, the foam coating comprises at least two layers, wherein the expansion rate of the foam coating on the outer layer away from the wire core is greater than the expansion rate of the foam coating on the inner layer.

[0010] In one embodiment of the present invention, a thermally responsive microcapsule is disposed within the foamed coating, the thermally responsive microcapsule comprising a filler material made of paraffin wax or a shape memory polymer.

[0011] In one embodiment of this utility model, thermally conductive particles are disposed within the foamed coating and / or insulating layer, and the thermally conductive particles are made of boron nitride nanosheets or alumina particles.

[0012] In one embodiment of the present invention, ceramic microspheres are embedded in the surface portion of the foamed coating, and the average particle size of the ceramic microspheres is 10μm-50μm.

[0013] In one embodiment of this utility model, the foam coating is made of polyurethane, epoxy resin, silicone or rubber foam material.

[0014] In one embodiment of this utility model, the foamed coating is a closed-loop coating structure that completely covers the outer peripheral surface of the insulating layer.

[0015] In one embodiment of this utility model, the cross-sectional shape of the enameled wire is a flat wire, a round wire, or an irregularly shaped wire, and the irregularly shaped wire is an elliptical or polygonal cross-section.

[0016] To achieve the above and other related objectives, this utility model provides a motor stator, comprising:

[0017] A winding, the winding comprising the enameled wire;

[0018] Stator body, including stator slots;

[0019] The foamed coating fills the gap between the enameled wire and the stator groove after it expands through foaming.

[0020] In one embodiment of this utility model, a limiting groove is provided on the inner wall of the stator slot. After the foamed coating expands due to heat to form a foamed layer, it fills the gap between the enameled wire and the stator slot. The surface protrusions of the foamed layer complement the shape of the limiting groove to form a mechanical interlock.

[0021] In summary, the enameled wire structure of this invention includes a core, an insulation layer, and a foam coating. The foam coating releases gas through heating or a chemical reaction, forming a porous foam structure that expands to fill the gap between the enameled wire and the stator slots. The expanded foam layer is fixed through a combination of physical interlocking and friction, simplifying the winding fixing process, shortening the production cycle, reducing equipment investment and material costs. Furthermore, the improved compatibility between the foam layer and the stator slots reduces the risk of vibration due to uneven gaps, thereby improving the overall performance and lifespan of the motor. Simultaneously, the self-adaptive filling characteristics of the foam layer allow for compatibility with stator slot structures of different sizes, avoiding assembly defects caused by dimensional tolerances in traditional processes. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the enameled wire structure when the foamed coating is not foamed, according to one embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the enameled wire structure after the foamed coating is foamed in one embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of an enameled wire just installed into the stator body in one embodiment of the present invention, wherein the gap between the stator groove and the enameled wire is the filling area after the foamed coating is foamed.

[0026] Figure 4 This is a schematic diagram of the structure of the enameled wire with foamed coating in the stator body according to another embodiment of the present invention;

[0027] Component labeling description: Enamelled wire 10, wire core 1, insulation layer 2, foam coating 3, foam layer 31, stator body 20, stator slot 21, limit slot 211. Detailed Implementation

[0028] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. It should also be understood that the terminology used in the embodiments of this utility model is for describing specific implementation schemes and not for limiting the scope of protection of this utility model. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0029] Please see Figures 1 to 4It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0030] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention.

[0031] Please see Figure 1-4 This utility model provides an enameled wire 10, including a wire core 1, an insulation layer 2 covering the outside of the wire core 1, and a foam coating 3 capable of forming a foam layer 31 through foaming expansion, wherein the foam coating 3 covers the outer surface of the insulation layer 2; wherein the thickness of the foam layer 31 is greater than the initial thickness of the foam coating 3; the foam coating 3 is configured to form the foam layer 31 by thermal expansion or chemical foaming agent.

[0032] It should be noted that the structure of the enameled wire 10 includes a core 1, an insulation layer 2, and a foam coating 3. The core 1, as the conductive core of the enameled wire 10, is typically made of copper, aluminum, or other highly conductive metals. Its cross-sectional shape can be designed as circular, rectangular, or irregular to adapt to the spatial layout requirements of different motor windings. For example, a rectangular core 1 can improve the slot fill factor, while some irregularly shaped cores 1 can optimize the electromagnetic field distribution. The material and geometric design of the core 1 directly affect the current-carrying capacity, mechanical strength, and thermal stability of the conductor, serving as the fundamental carrier for the functionality of the enameled wire 10. The insulation layer 2 tightly covers the outside of the core 1, its main function being to prevent current leakage and resist the erosion of the core 1 by the external environment (such as humidity and chemical corrosion). Its material can be selected from polymer materials such as polyester, polyimide, or polyurethane, or a multi-layer composite structure (such as polyimide + polytetrafluoroethylene) can be used to achieve synergistic enhancement of high-temperature resistance and wear resistance. The thickness and dielectric properties of the insulation layer 2 need to balance electrical safety and space occupation to ensure reliable insulation within the limited space of the slot. The foam coating 3 covers the outer surface of the insulation layer 2. Its core function is to fill the gap between the enameled wire 10 and the stator slot 21 through controlled expansion, thereby achieving self-fixation of the winding. The foaming triggering mechanism includes thermal expansion (such as heating to 80℃~150℃ to activate the foaming agent) or chemical foaming (such as decomposition reaction releasing gas), forming a porous foam structure. After expansion, the thickness of the foam layer 31 increases significantly, for example, from an initial 50μm to 200μm, thereby tightly adhering to the inner wall of the stator slot 21 and suppressing the movement of the enameled wire 10 through the dual action of physical interlocking and friction.

[0033] Traditional winding fixing techniques rely on slot wedge insertion or impregnation processes. The former requires manual operation and is inefficient, while the latter is costly due to complex equipment and long curing cycles. Furthermore, the rigid structure of existing slot wedges and impregnating varnishes is prone to micro-cracks due to thermal stress or vibration, reducing fixing reliability. This invention utilizes the self-expanding properties of the foam coating 3 to eliminate the manual insertion process and avoid reliance on expensive impregnation equipment. Simultaneously, the elasticity of the foam layer 31 adapts to thermal expansion and contraction and mechanical vibration, improving long-term stability.

[0034] The triggering mechanism of the foam coating 3 in this case is based on thermal expansion or the action of a chemical foaming agent. When the enameled wire 10 is inserted into the stator slot 21, the reserved gap provides space for the expansion of the foam layer 31. During motor assembly or operation, gas is released through heating (such as motor temperature rise) or chemical reaction, causing the volume of the foam coating 3 to increase and fill the gap. The expansion direction of the foam layer 31 is complementary to the gap of the stator slot 21, fixing the wire core 1 through the dual action of friction and physical interlocking, thereby suppressing cross-movement.

[0035] Specifically, after the enameled wire 10 is inserted into the stator slot 21, the reserved gap provides space for the expansion of the foam layer 31. During motor assembly or operation, gas is released through heating (such as motor temperature rise) or chemical reaction, forming a porous foam structure that expands to fill the gap between the enameled wire 10 and the stator slot 21. The expanded foam layer 31 is fixed through the dual action of physical interlocking and friction, thereby simplifying the winding fixing process, shortening the production cycle, reducing equipment investment, and improving the compatibility between the foam layer 31 and the stator slot 21, reducing the vibration risk caused by uneven gaps, thus improving the overall performance and lifespan of the motor. The self-adaptive filling characteristics of the foam layer 31 are compatible with stator slot 21 structures of different sizes, avoiding assembly defects caused by dimensional tolerances in traditional processes; the contact pressure generated by expansion is evenly distributed, avoiding damage to the insulation layer 2 caused by local stress concentration, which is more conducive to ensuring the electrical performance of the windings compared to mechanical pressing-in fixing schemes.

[0036] Please see Figure 1-4 As an optional embodiment of this case, the foam coating 3 includes at least two layers, wherein the expansion rate of the foam coating 3 on the outer layer away from the wire core 1 is greater than the expansion rate of the foam coating 3 on the inner layer.

[0037] It should be noted that the multi-layer gradient expansion structure design of the foamed coating 3 overcomes the limitations of a single expansion rate material in adapting to changes in assembly gaps. The outer layer, made of a high expansion rate material, can quickly fill larger gap areas within the stator slot 21, while the inner layer, made of a low expansion rate material, ensures strong interfacial bonding with the insulation layer 2. In alternative embodiments, the gradient structure can be extended to a three- or more-layered laminated system with progressively increasing expansion rates, or a transition layer with continuously varying expansion rates can be formed through a co-extrusion process. In terms of material selection, the outer layer can be made of silicone-based foam to achieve high ductility, while the inner layer can be made of polyurethane foam to maintain structural rigidity; or the outer layer can be made of epoxy resin with microcapsules to increase the expansion rate, while the inner layer can be made of rubber-based foam to enhance creep resistance. This solves the contradiction that a single expansion rate foam layer 31 cannot simultaneously meet the requirements of large gap filling and interface bonding reliability. In this case, the expansion gradient releases the deformation stress in different areas. The outer layer preferentially absorbs assembly gap deviations through deformation, while the inner layer suppresses the peeling of the insulation layer 2 caused by excessive expansion. This improves the compatibility of the winding with the dimensional fluctuations of the stator slot 21, while reducing the risk of coating cracking caused by expansion stress concentration and extending the service life of the enameled wire 10 in a vibration environment.

[0038] Please see Figure 1-4As an optional embodiment of this case, the expansion rate of the outer layer is 400%-500%, and the expansion rate of the inner layer is 150%-250%. Adjacent layers are bonded together through a gradient transition layer to avoid stress concentration at the interface and prevent delamination and cracking. Generally, the inner layer is cured first, and then the outer layer is coated, with the expansion rates controlled separately. Simultaneously, different foaming agents can be used for the inner and outer layers, such as a combination of chemical foaming agents and thermal expansion agents.

[0039] As an optional embodiment of this case, the foam coating 3 is provided with functional units inside or on its surface, and the functional units are at least one of thermally responsive microcapsules, thermally conductive particles and ceramic microspheres.

[0040] Please see Figure 1-4 As an optional embodiment of this case, thermally responsive microcapsules are uniformly dispersed within the foamed coating 3. The thermally responsive microcapsules include a filler material made of paraffin or shape memory polymer. The thermally responsive microcapsules are configured to trigger secondary expansion when the temperature reaches 80°C-150°C, with the expansion volume increasing by 20%-50%.

[0041] It should be noted that both paraffin wax and shape memory polymer are materials readily available in the prior art. It should also be understood that the foamed coating 3 can be made from other materials that meet the usage requirements. In this case, thermally responsive microcapsules are introduced into the foamed coating 3 to enhance the fixation reliability under extreme operating conditions. The thermally responsive microcapsules function by triggering secondary expansion through temperature, compensating for the attenuation of fixation force caused by changes in motor operating temperature. Specifically, paraffin wax or shape memory polymer, as the filling material of the microcapsules, can have its phase change or shape memory properties activated within the range of 80℃-150℃. For example, paraffin wax expands in volume when it changes from solid to liquid, or the shape memory polymer recovers its preset shape, thereby generating additional expansion pressure. This solves the problem of insufficient fixation force caused by material softening in a single foamed layer 31 under high temperature or vibration environments.

[0042] When the motor operating temperature reaches the threshold, the material inside the microcapsule undergoes physical or chemical changes, releasing expansion stress after breaking through the capsule wall's constraints. This dynamically enhances the contact pressure between the foamed layer 31 and the stator slot 21. Consequently, it not only improves the winding's resistance to displacement but also fills the gap caused by the difference in thermal expansion coefficients through secondary expansion, thereby significantly reducing the risk of lateral movement under extreme operating conditions.

[0043] Please see Figure 1-4 As an optional embodiment of this case, thermally conductive particles are uniformly dispersed within the foamed coating 3 and / or the insulating layer 2. These thermally conductive particles are made of boron nitride nanosheets or alumina particles. The amount of these thermally conductive particles added is 5%-15% of the mass of the foamed coating 3 or the insulating layer 2, used to improve heat dissipation performance.

[0044] It should be noted that both the boron nitride nanosheets and alumina particles are materials readily available in the prior art. It should also be understood that the thermally conductive particles can be made from other materials that meet the usage requirements. This invention balances the thermal insulation properties of the foam layer 31 with the heat dissipation needs of the motor by introducing high thermal conductivity particles into the foam coating 3 or the insulation layer 2. Boron nitride nanosheets, due to their high in-plane thermal conductivity (approximately 300 W / m·K), can form thermally conductive pathways, while alumina particles improve overall thermal diffusion efficiency through phonon scattering. The combined use of both can construct a three-dimensional thermally conductive network, avoiding increased thermal resistance caused by the porous structure of the foam layer 31. The addition range (5%-15%) balances improved thermal conductivity with material processability: below 5%, it is difficult to form a continuous thermally conductive path; above 15%, particle agglomeration may lead to a decrease in the uniformity of the foam layer 31. Furthermore, the particle size distribution can be further optimized, for example, by combining nanoscale sheet-like boron nitride (thickness <50 nm) with micron-sized alumina spheres (diameter 1-5 μm) to achieve synergistic layered and point-like thermal conductivity.

[0045] To address the insulation aging problem caused by overheating of motor windings, the foam coating 3 is expanded from a simple structural fixing function to a multi-functional layer with active heat dissipation by locally strengthening weak heat dissipation links (such as the high-density heat-generating area of ​​stator slot 21). The technical effect is reflected in reducing the temperature of winding hot spots while maintaining the original low density and flexibility of the foam layer 31, avoiding the sacrifice of foaming characteristics due to excessive thermally conductive filler.

[0046] Please see Figure 1-4 As an optional embodiment of this case, ceramic microspheres are embedded in the surface portion of the foamed coating 3. The average particle size of the ceramic microspheres is 10μm-50μm, which is used to enhance insulation and suppress cracking of the expansion layer.

[0047] It should be noted that the insulation performance and structural stability of the foamed coating 3 are optimized by embedding ceramic microspheres on the surface. The high hardness and chemical inertness of the ceramic microspheres (such as silica and alumina) can inhibit crack propagation caused by gas escape or stress concentration during the foaming process, while their high resistivity (>10¹) 4 The particle size (Ω·cm) can enhance the surface insulation strength. A particle size range of 10-50 μm balances the filling density and interfacial bonding strength; too small a particle size leads to agglomeration and reduced dispersibility, while too large a particle size causes interfacial delamination due to surface energy differences. Furthermore, surface treatment processes for microspheres (such as fluorosilane grafting) can improve compatibility with foaming resins. In addition to surface distribution, the embedding method can be designed with gradient concentration distributions (such as surface enrichment and internal reduction) to achieve layered optimization of insulation and mechanical properties.

[0048] This case utilizes the rigid filling effect of ceramic microspheres: on the one hand, the microspheres act as stress concentration points to absorb the tensile stress during foaming expansion, preventing cracks from propagating along the foam pore walls; on the other hand, their high volume resistivity forms a dense insulating layer 2 on the surface of the foam layer 31, preventing corona discharge or local breakdown, thereby effectively solving the problem of reduced insulation strength caused by the porous structure of the foam material, and extending the service life of the coating under vibration conditions by inhibiting cracking.

[0049] Please see Figure 1-4 As an optional embodiment of this case, the foam coating 3 is made of polyurethane, epoxy resin, silicone or rubber foam material.

[0050] It should be noted that the polyurethane, epoxy resin, silicone, or rubber foaming materials mentioned are all materials available in the prior art. It should be understood that the foam coating 3 can also be made of other materials that meet the requirements. The polyurethane has high elasticity and is suitable for motor environments with frequent vibrations; the epoxy resin has high bonding strength and is suitable for high-temperature scenarios; while silicone / rubber is resistant to aging and suitable for high-humidity environments. Furthermore, the foam coating 3 can also be made of high-temperature resistant polyimide foaming materials or low-cost acrylic resin materials. Traditional impregnating varnishes or adhesives struggle to balance expansion rate and insulation. This invention, through material optimization, achieves both mechanical fixing and insulation functions in the foam layer 31, simplifying the process and reducing costs.

[0051] Please see Figure 1-4 As an optional embodiment of this case, the foam coating 3 is a closed-loop coating structure that completely covers the outer peripheral surface of the insulating layer 2.

[0052] It should be noted that the closed-loop structure can be achieved in the following ways: for example, by impregnation coating, in which the enameled wire 10 is completely immersed in a foaming material solution to form a continuous coating layer; by spiral winding, in which the foamed tape is spirally wound around the insulation layer 2 and then heated and cured; or by compression molding, in which the foamed material is extruded through a mold to form a closed-loop structure. Traditional open-loop coatings (such as segmented coating) are prone to forming weak points at the interface. In this case, by making the foamed coating 3 a closed-loop coating structure, it can isolate the intrusion of external moisture and contaminants, avoiding the risk of breakdown caused by partial exposure of the insulation layer 2; at the same time, it enhances the overall mechanical strength of the enameled wire 10, making it suitable for harsh working conditions such as humidity and dust, and extending the life of the motor windings.

[0053] Please see Figure 1-4 As an optional embodiment of this case, the cross-sectional shape of the enameled wire 10 is a flat wire, a round wire, or an irregular wire, and the irregular wire is a rectangular, trapezoidal, elliptical, or polygonal cross-section.

[0054] It should be noted that flat wire is suitable for high slot fill factor motors, reducing the size of the winding ends; round wire is versatile and easy to automate winding; irregularly shaped wires with polygonal cross-sections, such as rectangular cross-sections, are suitable for square stator slots 21, and trapezoidal cross-sections match conical slot structures; elliptical cross-sections can reduce eddy current losses, and polygonal cross-sections can increase the heat dissipation area. Traditional round wires are prone to gaps in irregularly shaped slots, resulting in unstable fixing and uneven heat dissipation. This design reduces gaps and improves space utilization by matching the cross-sectional shape to the stator slots 21, thereby increasing the motor's power density; while irregularly shaped wires enhance heat dissipation by increasing the surface area, thereby improving the motor's thermal management efficiency.

[0055] Please see Figure 1-4 As an optional embodiment of this case, an adhesive layer is provided between the foam coating 3 and the insulating layer 2, and the adhesive layer is a thermosetting resin or pressure-sensitive adhesive.

[0056] It should be noted that thermosetting resins can be specifically defined as epoxy resins, phenolic resins, or silicone resins, while pressure-sensitive adhesives include acrylate or rubber-based adhesives. The adhesive layer can also be integrally formed with the insulating layer 2 through a co-extrusion process. The adhesive layer enhances the adhesion of the foam layer 31 to the enameled wire 10.

[0057] As an optional embodiment of this case, the foamed coating 3 is formed by spraying, impregnation, or bonding processes. Besides spraying and impregnation, bonding processes can be further refined into specific methods such as hot melt adhesive coating, hot roller bonding, or laser-assisted sintering. Spraying is suitable for high-speed mass production lines, impregnation is suitable for complex three-dimensional winding structures, and bonding facilitates local repairs or the processing of irregularly shaped parts.

[0058] Please see Figure 1-4 This utility model provides a motor stator, including a winding and a stator body 20; the winding includes the enameled wire 10; the stator body 20 includes a stator slot 21; the foamed coating 3 fills the gap between the enameled wire 10 and the stator slot 21 after foaming and expansion.

[0059] It should be noted that the winding uses the enameled wire 10, whose structure can cover round wire, flat wire, or rectangular wire, etc. The stator body 20 material can be expanded to silicon steel sheet lamination, soft magnetic composite material, or amorphous alloy structure. In addition to the traditional rectangular shape, the stator slot 21 can also be designed as trapezoidal, semi-circular, or wavy to adapt to different winding shapes and heat dissipation requirements. The filling function of the foam coating 3 is achieved through the material expansion characteristics. In addition to polyurethane or silicone-based foaming agents, pyrolytic precursors (such as polyimide foam precursors) can also be used for in-situ foaming, or the expansion direction can be precisely controlled through supercritical fluid foaming technology.

[0060] This design utilizes the controllable volume expansion characteristics of foamed materials to compensate for the manufacturing tolerance gap (typically 0.1-0.5mm) between the enameled wire 10 and the stator slot 21. Before expansion, the coating adheres to the winding surface in a liquid or solid state. Upon heating (such as during the impregnation process or motor operation), the foaming agent decomposes to generate gas, increasing the coating volume by 1.2-5 times, thus creating radial support for the winding. This process transforms the originally loose "wire-slot" gap into an interference fit, suppressing axial movement through a dual mechanism of friction and mechanical interference.

[0061] This solution directly addresses the vibration and displacement problem caused by gaps during the traditional embedding of enameled wire 10, making it particularly suitable for high-frequency vibration scenarios (such as electric vehicle drive motors). The technical benefits are threefold: first, it eliminates the impregnation process, reducing production costs and process complexity; second, its self-expansion characteristics significantly enhance winding fixing force, reducing electromagnetic noise; and third, the foamed layer 31 can reuse existing insulation systems, avoiding additional space occupation and increased thermal resistance caused by adding fixing devices.

[0062] Please see Figure 1-4 As an optional embodiment of this case, the inner wall of the stator groove 21 is provided with a limiting groove 211. After the foam coating 3 is heated and expands to form a foam layer 31, it fills the gap between the enameled wire 10 and the stator groove 21. The surface protrusion of the foam layer 31 complements the shape of the limiting groove 211 to form a mechanical interlock.

[0063] This design addresses the mechanical fixing problem between the stator slot 21 and the enameled wire 10 by implementing a multi-layered anti-displacement mechanism through the synergistic design of the limiting groove 211 and the foamed coating 3. For example, an axially wavy limiting groove 211 (e.g., 0.2~0.5mm deep) is designed on the core surface, complementing the corrugated shape of the expanded foamed coating 3. When the foamed coating 3 expands, it embeds into the limiting groove 211, forming a mechanical interlocking structure. The limiting groove 211 on the inner wall of the stator slot 21 can be visualized in various geometric shapes, such as rectangular grooves, trapezoidal grooves, or wavy textures, and its processing methods include laser etching, stamping, or electrochemical etching. The depth and width of the limiting groove 211 can be dynamically adjusted according to the winding dimensions to ensure matching with the expanded shape of the foamed coating 3. The realization of the mechanical interlocking structure relies on the geometric complementarity between the protrusions on the surface of the foamed coating 3 and the limiting groove 211. For example, when the limiting groove 211 is a rectangular array, the foam coating 3 can be designed as a pyramid-shaped protrusion; if the groove is wavy, the coating surface forms a sinusoidal ripple structure. The interlocking effect not only enhances the static fixing strength, but also resists high-frequency vibrations during motor operation through structural nesting, thus significantly reducing the winding displacement.

[0064] This solution addresses the issues of axial movement, radial vibration, and thermal expansion failure caused by gaps in traditional winding assembly through a mechanical interlock structure. The limiting groove 211 provides a rigid constraint frame, the foamed coating 3 fills microscopic irregular gaps through volume expansion, and the mechanical interlock forms a mechanical closed loop. The synergistic effect of these three elements significantly improves the reliability of winding fixation, thereby eliminating the need for additional binding processes, reducing the amount of impregnation varnish used, and accommodating the differentiated assembly requirements of motors with different power ratings. It is particularly suitable for high-dynamic operating conditions such as those in new energy vehicle drive motors.

[0065] In summary, this utility model effectively overcomes some practical problems in the prior art, thus having high utilization value and significance.

[0066] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. An enameled wire, characterized in that, include: wire core; An insulating layer covers the outside of the wire core; And a foamed coating capable of forming a foamed layer through foaming expansion, the foamed coating covering the outer surface of the insulating layer.

2. The enameled wire according to claim 1, characterized in that, The foam coating comprises at least two layers, wherein the expansion rate of the foam coating on the outer layer farther from the core is greater than that of the foam coating on the inner layer.

3. The enameled wire according to claim 1, characterized in that, The foamed coating contains thermally responsive microcapsules.

4. The enameled wire according to claim 1, characterized in that, The foamed coating and / or insulating layer contains thermally conductive particles.

5. The enameled wire according to claim 1, characterized in that, The surface portion of the foamed coating is embedded with ceramic microspheres, the average particle size of which is 10μm-50μm.

6. The enameled wire according to claim 1, characterized in that, The foam coating is made of polyurethane, epoxy resin, silicone or rubber foam material.

7. The enameled wire according to claim 1, characterized in that, The foamed coating has a closed-loop structure and completely covers the outer peripheral surface of the insulating layer.

8. The enameled wire according to claim 1, characterized in that, The cross-sectional shape of the enameled wire is a flat wire, a round wire, or an irregularly shaped wire, wherein the irregularly shaped wire is an elliptical or polygonal cross-section.

9. A motor stator, characterized in that, include: The winding comprises enameled wire as described in any one of claims 1-8; Stator body, including stator slots; The foamed coating fills the gap between the enameled wire and the stator groove after it expands through foaming.

10. The motor stator according to claim 9, characterized in that, The inner wall of the stator slot is provided with a limiting groove. After the foamed coating expands due to heat to form a foamed layer, it fills the gap between the enameled wire and the stator slot. The surface protrusions of the foamed layer complement the shape of the limiting groove to form a mechanical interlock.

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