A preformed coil and a method of manufacturing the same, electric machine

Abstract

The application discloses a prefabricated coil and a preparation method and a motor thereof, and relates to the technical field of motors.The preparation method comprises the following steps: preparing a coil holder according to the shape of a stator tooth structure; winding a coil on the coil holder, wherein the coil is a flat wire coil or a round wire coil; pretreating the coil holder and the coil, wherein the pretreatment comprises cleaning and drying treatment and mold installation; performing potting treatment on the coil holder and the coil, so that the potting material covers the surface of the coil and the gap between the turns; and performing segmented solidification treatment on the coil holder and the coil subjected to the potting treatment, so that the potting material is cross-linked and solidified.The prefabricated coil manufactured by the preparation method has stable structure, good heat dissipation, and can improve the assembly efficiency of the motor.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a pre-fabricated coil and its preparation method, and a motor. Background Technology

[0002] Motor coils are conductive windings in motors used to generate magnetic fields. They are usually made of insulated copper or aluminum wire and are embedded in the iron core slots of the stator or rotor. They are the core components for converting electrical energy into mechanical energy.

[0003] Currently, existing prefabricated coils have several problems: First, they lack adequate protection and heat dissipation during transportation and storage. The coils are mostly exposed or simply covered, making them prone to loosening during transport and damage to the insulation layer. Furthermore, they lack dedicated heat-conducting structures, resulting in concentrated heat after assembly and affecting motor stability. Second, the prefabricated coils have poor compatibility with the motor tooth space and low heat conduction efficiency. The standardized shape design of the coils leads to a large gap between them and the tooth space after assembly, making it easy for air bubbles to form when filling with additional heat-conducting material, resulting in uneven heat conduction. Third, the motor assembly process is cumbersome and quality is difficult to control. After the prefabricated coils are installed, the stator needs secondary insulation potting, adding steps to the process. During potting, air bubbles can easily form due to coil obstruction, and unfilled dead zones can lead to insulation failure.

[0004] Therefore, current prefabricated coils suffer from technical problems such as insufficient structural stability, poor heat dissipation, and low assembly efficiency. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a prefabricated coil and its preparation method, as well as a motor, to solve the technical problems of insufficient structural stability, poor heat dissipation, and low assembly efficiency of prefabricated coils in the prior art.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a pre-fabricated coil, the method comprising: preparing a coil frame according to the shape of the stator tooth structure; winding a coil on the coil frame, the coil being a flat wire coil or a round wire coil; pre-treating the coil frame and the coil, the pre-treating including cleaning and drying treatment and mold installation; potting the coil frame and the coil so that the potting material covers the surface of the coil and the gaps between the turns; and performing a segmented curing treatment on the potted coil frame and the coil to cross-link and cure the potting material.

[0007] In some embodiments, winding a coil on a coil frame includes: winding a flat wire coil on the coil frame, wherein the side of the flat wire coil with a larger area is in contact with the coil frame, and the winding tension F1 satisfies F1=KS. 2 k 2 The smaller side of the flat wire coil is in contact with the coil frame, and the winding tension F1 satisfies the condition F1=KS.2 k -2 Where K is the winding process coefficient, S is the cross-sectional area of ​​the coil, and k is the flatness ratio of the flat wire coil; the axial wire spacing L1 of the flat wire coil and the thickness T1 of the flat wire coil satisfy L1≤1.05T1.

[0008] In some embodiments, winding a coil on a coil frame includes: winding a round wire coil on the coil frame, wherein the winding tension F2 satisfies F2=KS. 2 K is the winding process coefficient, S is the cross-sectional area of ​​the coil, L2 is the axial wire spacing of the round wire coil, and T2 is the diameter of the round wire coil, which satisfies L2≤1.05T2.

[0009] In some embodiments, the coil frame and coil are pre-treated, including cleaning and drying, and mold installation includes: cleaning and drying the coil frame and coil; placing the coil frame and coil into a mold, the gap between the mold and the coil being used to form a potting layer, the thickness T3 of the potting layer satisfying T3=pW, where p is the potting ratio coefficient, W is the thickness of the coil, and 0.5≤p≤2; the mold is used to form a gap groove at the junction of adjacent coils, the gap groove L3 satisfying 0.1mm≤L3≤0.3mm.

[0010] In some embodiments, potting the coil frame and coil to cover the coil surface and the gaps between the coil turns with potting material includes: potting the coil frame and coil with potting material having a thermal conductivity ≥0.8W / m·K, an insulation class ≥F, and a volume shrinkage rate ≤5% to cover the coil surface and the gaps between the coil turns.

[0011] In some embodiments, the potting process involves segmented curing of the coil frame and coil to achieve cross-linking and curing of the potting material, including: a first stage of curing at a temperature between 70°C and 80°C for 60-120 minutes to initially cross-link the potting material; a second stage of curing at a temperature between 95°C and 105°C for 45-90 minutes to promote complete cross-linking of the potting material; and a third stage of curing at a temperature between 115°C and 125°C for 30-60 minutes to ensure complete curing of the potting material.

[0012] In some embodiments, after the coil frame and coil of the potting process are subjected to segmented curing to crosslink and cure the potting material, the preparation method further includes: performing post-processing according to the shape of the stator tooth structure, the post-processing including trimming and inspection.

[0013] Secondly, the present invention also provides a prefabricated coil manufactured using the above-described preparation method, comprising a coil frame, a coil, and a potting layer, wherein the coil is wound on the coil frame; and the potting layer covers the surface of the coil and the gaps between the coil turns.

[0014] In some embodiments, the coil frame is provided with a guide cone surface and a limiting boss, the guide cone surface is used to engage with the stator teeth, and the limiting boss abuts against the coil.

[0015] Thirdly, the present invention also provides an electric motor comprising the aforementioned pre-fabricated coil.

[0016] Compared with existing technologies, the present invention provides a method for preparing a prefabricated coil. By fully encapsulating the coil frame and coil, the encapsulating material solidifies to form a rigid protective shell. This not only improves the coil's impact resistance and prevents loosening of the coil turns and damage to the insulation layer during transportation and storage, but also ensures uniform heat distribution within the coil. Furthermore, the prefabricated coil has an integrated insulating encapsulation layer, eliminating the need for a secondary insulating encapsulation process after motor assembly, thus improving overall motor assembly efficiency and avoiding quality risks such as air bubbles and filling dead zones that are common with secondary encapsulation. In addition, the method uses a coil frame that matches the stator tooth structure, further improving the assembly efficiency of the prefabricated coil and stator, optimizing the heat conduction path between the coil and stator teeth, and enhancing heat dissipation performance. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the method for preparing a pre-fabricated coil provided in an embodiment of the present invention. Figure 1 ; Figure 2 This is a flowchart illustrating the method for preparing flat wire preformed coils provided in this embodiment of the invention. Figure 2 ; Figure 3 This is a flowchart illustrating the method for preparing a round wire pre-coil provided in an embodiment of the present invention. Figure 3 ; Figure 4 This is a flowchart illustrating the method for preparing a pre-fabricated coil provided in an embodiment of the present invention. Figure 4 ; Figure 5 This is a schematic flowchart of the pre-coil fabrication method provided in this embodiment of the invention. Figure 5 ; Figure 6 This is a schematic diagram of a prefabricated coil provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a coil frame provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of a motor stator provided in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 10. Motor stator; 100. Preparation method; 200. Prefabricated coil; 210. Coil frame; 211. Guide cone surface; 212. Limiting boss; 220. Coil; 300. Stator gear assembly; 400, Circular Pole Boots. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] Currently, most prefabricated coils are bare or simply wrapped, making the coils prone to loosening and the insulation layer easily damaged during transportation. They also lack a dedicated heat-conducting structure. Furthermore, the gap between the coil and the tooth space is large after assembly, and air bubbles are easily generated when filling with additional heat-conducting material, leading to uneven heat conduction. In addition, the assembly process is cumbersome and the quality is difficult to control, requiring secondary insulation potting. Air bubbles and dead corners caused by coil obstruction can easily lead to insulation failure.

[0021] To address the technical problems of insufficient structural stability, poor heat dissipation, and low assembly efficiency of prefabricated coils, this invention provides a method for preparing prefabricated coils. The prefabricated coils manufactured by this method have a stable structure, good heat dissipation, and can also improve the assembly efficiency of motors.

[0022] It should be noted that the preformed coil manufactured by the preparation method provided by the present invention is used in, but not limited to, frameless torque motors. For ease of explanation, this invention will only use the application of preformed coils in frameless torque motors as an example. The principle of applying preformed coils to other types of equipment is essentially the same as that of applying them to frameless torque motors, and will not be described in detail here.

[0023] This invention provides a method 100 for preparing a pre-fabricated coil, such as... Figure 1 As shown, the preparation method 100 includes: Step S110: Prepare the coil frame according to the shape of the stator tooth structure.

[0024] Specifically, the bobbin provides a winding carrier for the coil. The bobbin can be customized according to the shape of the stator tooth structure. For example, the bobbin is designed according to the structure of the T-tooth, allowing the bobbin to be inserted from the bottom of the T-tooth. Its specific structure will be described in the implementation section below.

[0025] In this embodiment, the coil frame is made of high-temperature resistant insulating material. For example, PA66 and GF30 (glass fiber reinforced nylon) are reinforced modified engineering plastics of nylon 66 with 30% glass fiber added. The coil frame needs to meet the requirements of insulation and high temperature resistance to ensure that it can withstand the temperature shock of winding and potting curing. For example, the insulation class of the coil frame is ≥F and the heat distortion temperature is ≥200℃.

[0026] In this embodiment, the coil frame is manufactured using injection molding, with mold precision controlled within ±0.02mm to ensure the roundness of the inner hole of the coil frame and related design accuracy. For example, the injection molding equipment parameters are: barrel temperature 260-280℃, mold temperature 80-100℃, injection pressure 80-100MPa, holding pressure 50-60MPa, and cooling time 15-20s.

[0027] In this embodiment, for quality control purposes, the coil frame surface is free of burrs and shrinkage cavities, and the insulation resistance is ≥1×10¹. 4 Ω (ASTM D257 standard), dimensional accuracy meets ±0.02mm requirement.

[0028] Step S120: Wind a coil on a coil frame. The coil is a flat wire coil or a round wire coil.

[0029] Specifically, after the coil frame is manufactured, an automated precision winding machine is used to wind the coil on the customized coil frame, ensuring tight winding, intact insulation, and compatibility with subsequent potting processes. The automated precision winding machine has functions such as tension control, axial winding, and winding counting.

[0030] It should be noted that either flat wire coils or round wire coils can be selected according to actual needs. Flat wire coils and round wire coils will be described in detail later through examples.

[0031] In this embodiment, for quality control, the coil is not loose or has skipped turns after winding, and the insulation layer is free of scratches. For example, the insulation resistance is ≥100MΩ and the axial dimension error of the coil is ≤±0.1mm when tested with a 500V megohmmeter.

[0032] Step S130: Pre-process the coil frame and coil, including cleaning, drying and mold installation.

[0033] Specifically, after the coil is wound on the coil holder, the coil holder and coil need to be pre-treated. Pre-treatment mainly removes impurities and moisture from the surfaces of the coil and coil holder, and lays the foundation for a tight bond between the potting material and the coil holder and coil. After cleaning and drying, the mold is installed. The specific cleaning and drying process, as well as the specific mold installation process, will be described later through examples.

[0034] Step S140: The coil frame and coil are potted so that the potting material covers the surface of the coil and the gaps between the coil turns.

[0035] Specifically, after pre-treating the coil frame and coil, a vacuum potting machine is used to inject potting material. A customized mold is used to achieve a potting shape that fits the inter-tooth space, while simultaneously providing the potting layer with protective, thermally conductive, and insulating functions. The potting material is not limited, as long as it meets the requirements of protection, thermal conductivity, and insulation. For example, a high thermal conductivity insulating epoxy resin (such as LD-S106, epoxy potting compound) can be used. Examples of relevant performance parameters will be given later. The vacuum potting machine can perform material mixing, vacuum degassing, and quantitative filling functions.

[0036] In this embodiment, for the control of the potting process, the material ratio is as follows: A:B = 6:1 by weight (e.g., LD-S106) is precisely mixed for 5-8 minutes to ensure uniformity and no sedimentation; vacuum degassing: the mixed potting material is degassed under a vacuum of ≤-0.09MPa for 10-20 minutes to completely remove air bubbles; potting operation: the degassed potting material is slowly injected into the mold cavity at a speed of 5-10ml / s to avoid generating turbulent air bubbles; the potting volume is based on completely filling the mold cavity, slightly exceeding the cavity volume by 5% to ensure no unfilled dead corners; secondary degassing: after potting, the mold along with the coil is placed in a vacuum chamber and degassed again under a vacuum of ≤-0.09MPa for 5-10 minutes to remove air bubbles generated during the potting process.

[0037] In this embodiment, for quality control, real-time observation is conducted during the filling process to ensure that there are no air bubbles or leaks; the potting material covers all surfaces of the coil and the gaps between the coil turns, and there is no obvious interface separation between the coil frame and the potting material.

[0038] Step S150: Perform segmented curing treatment on the potting coil frame and coil to cross-link and cure the potting material.

[0039] Specifically, after potting the coil frame and coil, staged heating and curing are used to ensure the potting material is fully cross-linked and cured, while simultaneously reducing internal stress generated during curing and preventing cracking of the potting layer. A precision constant-temperature oven with a temperature control accuracy of ±2℃ can be used for curing. The number of staged curing cycles can be determined according to actual needs, and relevant examples will be provided later.

[0040] In this embodiment, for quality control, the surface of the cured potting layer should be as smooth as possible, free of cracks and bubbles, and the Shore hardness D ≥ 85; the insulation resistance of the potting layer should be ≥ 1 × 10¹ when tested with a 500V megohmmeter. 4 Ω.

[0041] It should be noted that after the segmented curing process is completed, post-processing can be carried out according to actual needs. Post-processing includes trimming and testing, which will be described in detail later.

[0042] In this embodiment, by fully encapsulating the coil frame and coil, the encapsulating material solidifies to form a rigid protective shell. This not only enhances the coil's impact resistance and prevents loosening of the coil windings and damage to the insulation layer during transportation and storage, but also ensures uniform heat distribution within the coil. Furthermore, the prefabricated coil's integrated insulating encapsulation layer eliminates the need for a secondary insulating encapsulation process after motor assembly, improving overall motor assembly efficiency and avoiding quality risks such as air bubbles and filling dead zones that are common with secondary encapsulation. In addition, the method employs a coil frame that matches the stator tooth structure, further improving the assembly efficiency of the prefabricated coil and stator, optimizing the heat conduction path between the coil and stator teeth, and enhancing heat dissipation performance.

[0043] In some embodiments, such as Figure 2 As shown, step S120, winding the coil on the coil holder, includes: Step S121: Wind a flat wire coil on the coil frame, with the side of the flat wire coil having a larger area in contact with the coil frame, and the winding tension F1 satisfies the condition F1=KS 2 k 2 The smaller side of the flat wire coil is in contact with the coil frame, and the winding tension F1 satisfies the condition F1=KS. 2 k -2 Where K is the winding process coefficient, S is the cross-sectional area of ​​the coil, and k is the flatness ratio of the flat wire coil; the axial wire spacing L1 of the flat wire coil and the thickness T1 of the flat wire coil satisfy L1≤1.05T1.

[0044] In this embodiment, the flat wire coil is an F-grade insulated enameled copper flat wire. The specific cross-sectional dimensions of the flat wire coil can be designed according to the motor power. For example, the width of the flat wire coil is 4mm, the thickness of the flat wire coil is 2mm, and the slot fill factor is ≥85%.

[0045] In this embodiment, the winding tension F1 of the flat wire coil is related to the winding process coefficient, the cross-sectional area of ​​the coil, and the aspect ratio of the flat wire coil. It can be determined according to actual needs. For example, if the side of the flat wire coil with a larger area is in contact with the coil frame, the winding tension F1 is positively correlated with the aspect ratio; conversely, if the side of the flat wire coil with a smaller area is in contact with the coil frame, the winding tension F1 is negatively correlated with the aspect ratio. The aspect ratio of the flat wire coil is the width-to-height ratio of its cross-section. For example, the winding tension F1 of the flat wire coil is between 5N and 8N, such as 5N, 6N, 7N, 8N, etc., to avoid excessive tension damaging the insulation layer. Regarding the wiring accuracy, the axial wiring spacing L1 and the thickness T1 of the flat wire coil are considered. L1 is the distance between the center axes of two adjacent flat wire coils, meaning that the axial center distance between two adjacent flat wires cannot exceed 1.05 times the thickness of the flat wire. For example, the thickness T1 of the flat wire coil is 2mm, and the maximum allowable wiring spacing L1 is 2.1mm. The number of winding turns can be precisely controlled according to the motor design requirements. For example, two adjacent flat wires are completely fitted together.

[0046] It should be noted that, for tap processing, the taps at both ends of the coil can be either reserved or fixed on the coil frame, and subsequent wiring can be done through PCBA (Printed Circuit Board Assembly).

[0047] In some embodiments, such as Figure 3 As shown, step S120, winding the coil on the coil holder, includes: Step S122: Wind a round coil on the coil frame, with the winding tension F2 satisfying the condition F2=KS 2 K is the winding process coefficient, S is the cross-sectional area of ​​the coil, L2 is the axial wire spacing of the round wire coil, and T2 is the diameter of the round wire coil, which satisfies L2≤1.05T2.

[0048] In this embodiment, the round wire coil is an F-grade insulated enameled copper round wire. The diameter of the round wire coil is determined according to the winding space design of the coil frame to ensure that the wire turns are tight and not loose after winding.

[0049] In this embodiment, the winding tension F2 of the round wire coil is related to the winding process coefficient and the cross-sectional area of ​​the coil, and can be determined according to actual needs. For example, the winding tension F2 of the round wire coil is between 3N and 5N, such as 3N, 4N, 5N, etc., to avoid excessive tension damaging the insulation layer. Regarding the wiring accuracy, the axial wiring spacing L2 of the round wire coil and the diameter T2 of the round wire coil are used. L2 is the distance between the central axes of two adjacent round wire coils, meaning that the axial center distance between two adjacent round wires cannot exceed 1.05 times the diameter of the round wire coil.

[0050] In some embodiments, such as Figure 4As shown, in step S130, the coil frame and coil are pre-treated. The pre-treatment includes cleaning, drying, and mold installation. Step S131: Clean and dry the coil holder and coil.

[0051] In this embodiment, the cleaning process can involve wiping the coil frame and coil surface with anhydrous ethanol to remove oil, dust, and other impurities. For example, for flat wire coils, it is necessary to focus on cleaning impurities between the coil turns to ensure that the potting material can fully penetrate. The drying process involves placing the cleaned coil frame and coil into an oven and baking at a temperature controlled at 100℃-120℃ for 2-3 hours to thoroughly remove moisture (moisture content ≤0.1%) and prevent air bubbles from forming due to moisture evaporation after potting.

[0052] Step S132: Place the coil frame and coil into the mold. The gap between the mold and the coil is used to form a potting layer. The thickness T3 of the potting layer satisfies T3=pW, where p is the potting ratio coefficient and W is the thickness of the coil, 0.5≤p≤2. The mold is used to form a gap groove at the junction of adjacent coils. The gap groove L3 satisfies 0.1mm≤L3≤0.3mm.

[0053] In this embodiment, mold installation is performed after cleaning and drying. For pre-assembly positioning, the dried coil frame and coil are placed into a customized potting mold based on the stator teeth. For example, the mold positioning pins are precisely positioned against the limiting boss on the top of the coil frame to ensure that the potting shape perfectly matches the space between the teeth. The gap between the mold and the coil can be determined according to actual needs, i.e., the potting layer thickness T3 can be determined based on the potting ratio coefficient p and the coil thickness W, 0.5≤p≤2, for example, 1mm, 2mm, etc. At the same time, a gap groove L3 of 0.1-0.3mm is reserved at the connection between adjacent coils in the mold, for example, 0.1mm, 0.2mm, 0.3mm, etc. This ensures that adjacent potting layers can form a heat conduction channel after subsequent assembly.

[0054] For example, mold pretreatment can also be performed by applying a release agent, such as a silicone-based release agent, to the inner wall of the potting mold to ensure that the potting can be easily demolded after curing without affecting the surface quality of the potting layer.

[0055] In some embodiments, such as Figure 4 As shown, step S140, which involves potting the coil frame and coil to ensure that the potting material covers the surface of the coil and the gaps between the coil turns, includes: Step S141: The coil frame and coil are potted by using potting material with a thermal conductivity ≥0.8W / m·K, insulation class ≥F, and volume shrinkage rate ≤5% to cover the surface of the coil and the gaps between the coil turns.

[0056] In this embodiment, the potting material is a high thermal conductivity insulating epoxy resin, including but not limited to LD-S106 (epoxy potting compound), EFI Polymers (high thermal conductivity epoxy resin), etc. The key performance parameters of the potting material are met: thermal conductivity ≥ 0.8 W / m·K, ensuring rapid heat transfer; insulation class ≥ F (155℃), withstand voltage ≥ 20 KV / mm, ensuring motor insulation performance; volume shrinkage ≤ 5%, ensuring dimensional stability after curing and preventing increased gaps due to shrinkage; low viscosity (e.g., 15000-20000 cps for material A and 40-50 cps for material B at 40℃), good flowability, and sufficient penetration into the gaps between wire turns.

[0057] In some embodiments, such as Figure 4 As shown, step S150, which involves segmented curing of the potting coil frame and coil to achieve cross-linking and curing of the potting material, includes: Step S151, the first stage of curing, the curing temperature is between 70℃ and 80℃, the heat preservation time is 60min-120min, so that the potting material is initially cross-linked.

[0058] Specifically, using LD-S106 potting compound, it can be cured in three stages. For example, the first stage of curing is carried out at a temperature of 75°C for 2 hours to allow the potting material to initially cross-link and avoid stress concentration caused by rapid heating.

[0059] Step S152, the second stage of curing, the curing temperature is between 95℃ and 105℃, the heat preservation time is 45min-90min, to promote the complete cross-linking of the potting material.

[0060] Specifically, after the first stage of curing is completed, a second stage of curing is carried out. For example, the temperature of the second stage of curing is 100°C and the temperature is maintained for 1 hour to promote complete cross-linking of the material and improve its mechanical and thermal properties.

[0061] Step S153, the third stage of curing, the curing temperature is between 115℃ and 125℃, the heat preservation time is 30min-60min, so that the potting material is completely cured.

[0062] Specifically, after the second stage of curing is completed, a third stage of curing is carried out. For example, the temperature of the third stage of curing is 120°C, and the temperature is maintained for 1 hour to further eliminate internal stress and ensure complete curing.

[0063] Step S154: After curing, cool the potting layer to room temperature in the oven (cooling rate ≤5℃ / min) to avoid thermal stress cracking between the potting layer and the coil frame and coil due to rapid cooling.

[0064] In some embodiments, such as Figure 5As shown, in step S150, the coil frame and coil undergo segmented curing treatment to crosslink and cure the potting material. After this process, the preparation method 100 further includes: In step S160, post-processing is performed according to the shape of the stator tooth structure. Post-processing includes trimming and inspection.

[0065] In this embodiment, the post-processing operation is used to remove excess potting material, trim the dimensions of the potting layer, and ensure the accuracy of insertion with the stator teeth and connection with adjacent coils. Trimming includes demolding, precision trimming, and tapping. Demolding involves removing the cured pre-made coil from the mold and removing excess adhesive. Precision trimming uses a precision grinder (equipped with a diamond wheel) to grind the surface of the potting layer. For axial dimensions, the axial length error of the potted coil is ensured to be ≤±0.05mm, precisely matching the length of the stator teeth. For radial dimensions, the outer diameter error of the potting layer is ≤±0.03mm, ensuring a gap of ≤0.1mm between the coil and the teeth. Regarding gap allowance, it is confirmed that the 0.1-0.3mm gap at the connection of adjacent coils is not blocked by excess potting material; if blocked, it is cleaned with a micro drill bit (0.2mm diameter). Tap preparation involves cleaning the potting material from the coil taps to ensure that the metal parts of the taps are exposed for 5-8mm, facilitating subsequent soldering to the PCB (printed circuit board); and providing secondary insulation protection (heat shrink tubing encapsulation) to the taps. In this embodiment, the testing includes dimensional inspection, electrical inspection, and mechanical inspection. Dimensional inspection: The key dimensions of the encapsulated coil (outer diameter, axial length, and gap dimension) are inspected using a coordinate measuring machine to ensure compliance with design requirements; Electrical inspection: The withstand voltage performance of the encapsulation layer is tested using a 1000V withstand voltage tester, with no breakdown or flashover; the coil insulation resistance is tested using a megohmmeter and found to be ≥100MΩ; Mechanical inspection: The encapsulation layer is subjected to an impact test (impact energy 0.5J), with no cracking or peeling.

[0066] This application embodiment also provides a prefabricated coil 200, such as Figure 6 As shown, the device is manufactured using the above-described preparation method 100, and includes a coil frame 210, a coil 220, and a potting layer. The coil 220 is wound on the coil frame 210. The potting layer covers the surface of the coil 220 and the gaps between the coil turns.

[0067] In this embodiment, the example of a prefabricated coil 200 adapted to a T-shaped tooth is used for illustration. The inner diameter of the coil frame 210 is 0.05-0.1mm larger than the diameter of the T-shaped tooth to ensure smooth insertion; the thickness of the potting layer is 1-2mm.

[0068] In some embodiments, such as Figure 6 and Figure 7As shown, the coil frame 210 is provided with a guide cone surface 211 and a limiting boss 212. The guide cone surface 211 is used to fit with the stator teeth, and the limiting boss 212 abuts against the coil 220.

[0069] In this embodiment, the coil holder 210 is provided with a guiding structure and a positioning structure. The guiding structure is a guide cone surface 211, and the taper of the guide cone surface can be determined according to actual needs to match the guiding structure at the bottom of the T-shaped teeth and avoid scratches during winding. For example, the bottom of the coil holder is provided with a guide cone surface 211 with a taper of 1:10. The positioning structure is a limiting boss 212, which is located at the top of the coil holder 210. It restricts the axial displacement of the coil 220 during winding and also serves as a positioning reference for the potting mold.

[0070] This application also provides a motor, such as... Figure 8 As shown, the motor includes a prefabricated coil 200.

[0071] In this embodiment, the motor includes a motor stator 10, which includes a stator gear assembly 300, a pre-fabricated coil 200, and an annular pole shoe 400. For example, the stator gear assembly is a straight-chain T-type stator gear.

[0072] To facilitate understanding, the assembly and connection steps of the prefabricated coil 200 with the overall motor process are also explained below. The purpose is to precisely assemble the prepared prefabricated coil onto the T-shaped straight toothed assembly, forming an integrated insulating and thermally conductive whole through the connection of adjacent coil potting layers, eliminating the need for secondary potting. The specific assembly includes the following steps: Pre-fabricated coil installation: The post-processed pre-fabricated coils are guided one by one from the bottom of the T-shaped straight teeth to the teeth, using the guide cone surface at the bottom of the coil holder. During the installation process, it is necessary to ensure that the coil encapsulation layer is tightly fitted to the T-shaped tooth wall without any looseness. N pre-fabricated coils are installed one-to-one into N T-shaped teeth to complete the assembly of the stator tooth assembly.

[0073] Circular pole shoe riveting to a complete circle: The assembled straight-chain T-shaped stator teeth are wound into an approximate ring and fitted with a circular pole shoe; the riveting protrusions on the pole shoe and the notches of the T-shaped teeth are used for forced riveting, forming the assembly into a complete circular structure. The riveting pressure is controlled at 50-80kN, and the coil potting layer must remain free from deformation and cracking during this process; after riveting, the potting layers of adjacent prefabricated coils are tightly connected through a pre-reserved gap of 0.1-0.3mm, forming a continuous heat conduction channel.

[0074] Welding and Shaping: Laser welding is performed at the head and tail connections of the straight-chain T-type stator teeth after winding. During the welding process, the pole shoes continuously provide rigid constraints to the components to ensure welding accuracy and structural stability. The local welding temperature must be controlled at ≤80℃ to ensure that the potting layer does not age or crack.

[0075] Integrated insulation and thermal conductivity verification: After welding, the potting layer of adjacent prefabricated coils in the motor stator forms an integral structure, fully covering all coil surfaces and inter-tooth gaps, achieving full-range insulation protection for the stator windings. Thermal imaging is used to inspect the components; during motor operation, heat from adjacent teeth can be rapidly transferred through the potting layer, with a temperature difference between teeth ≤5℃, meeting insulation and thermal conductivity requirements without the need for additional insulation potting.

[0076] PCB integration connection: The taps of the prefabricated coil are soldered to the preset pads on the ring PCB board to complete the star or delta connection of the winding, and finally form a complete motor stator.

[0077] It should be noted that the manufacturing of pre-fabricated coils and their application in motors also have the following advantages: High feasibility for industrialization: The process relies on existing mature equipment such as automated winding machines and vacuum potting machines. Only the mold needs to be customized, and no new special equipment is required. The potting material can be directly selected from existing high thermal conductivity and insulating epoxy resin, which is readily available and cost-controllable.

[0078] Strong process integration: The process design is fully compatible with the core solution of "straight chain T-type stator tooth insertion + circular pole shoe riveting to form a circle + post-welding". The pre-made coil after potting can be directly inserted from the bottom of the T-type tooth. During the riveting process, the potting layer can withstand the riveting pressure of the pole shoe. During the welding process, the potting layer can withstand the local temperature below 80℃ (the potting material has a temperature resistance of ≥155℃), without affecting the overall assembly quality of the motor.

[0079] Wide range of applications: It can be directly applied to humanoid robot joint motors, precision machine tool spindle motors, aerospace precision transmission motors and other scenarios with extremely high requirements for size, efficiency and reliability; by eliminating the secondary potting process, improving assembly efficiency and reducing scrap rate (the scrap rate caused by secondary potting bubbles is reduced from 15% to below 3%), the manufacturing cost of a single motor is reduced by 20-30%, while the motor efficiency is improved by 5-8%.

[0080] Reliable stability: The pre-coated coils do not crack after being cycled 10 times at temperatures ranging from -45℃ to 155℃. The insulation performance does not degrade in humid environments, and it can be stored for a long time (shelf life ≥ 1 year) and transported, meeting the logistics needs of industrialized mass production.

[0081] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a pre-fabricated coil, characterized in that, include: Based on the shape of the stator teeth structure, the coil frame is prepared; A coil is wound on the coil frame, and the coil is a flat wire coil or a round wire coil; A flat wire coil is wound on the coil frame, with the larger side of the flat wire coil in contact with the coil frame, and the winding tension F1 satisfies the condition F1=KS. 2 k 2 The side of the flat wire coil with the smaller area is in contact with the coil frame, and the winding tension F1 satisfies the condition F1=KS. 2 k -2 k is the aspect ratio of the flat wire coil; the axial wire spacing L1 of the flat wire coil and the thickness T1 of the flat wire coil satisfy L1≤1.05T1; a round wire coil is wound on the coil frame, and the winding tension F2 satisfies F2=KS 2 The axial wire spacing L2 of the circular wire coil and the diameter T2 of the circular wire coil satisfy L2≤1.05T2; where F1 and F2 are the winding tensions; K is the winding process coefficient; and S is the cross-sectional area of ​​the coil. The coil frame and the coil are pre-treated, including cleaning and drying and mold installation; The coil frame and the coil are potted so that the potting material covers the surface of the coil and the gaps between the coil turns; The coil frame and the coil undergo segmented curing treatment to cross-link and cure the potting material.

2. The preparation method according to claim 1, characterized in that, The pretreatment of the coil frame and the coil includes cleaning, drying, and mold installation. The coil frame and the coil are cleaned and dried. The coil frame and the coil are placed in the mold. The gap between the mold and the coil is used to form a potting layer. The thickness T3 of the potting layer satisfies T3=pW, where p is the potting ratio coefficient and W is the thickness of the coil, and 0.5≤p≤2. The mold is used to form a gap groove at the junction of adjacent coils. The gap groove L3 satisfies 0.1mm≤L3≤0.3mm.

3. The preparation method according to claim 2, characterized in that, The potting process for the coil frame and the coil, so that the potting material covers the surface of the coil and the gaps between the coil turns, includes: The coil frame and the coil are potted by using a potting material with a thermal conductivity ≥0.8W / m·K, insulation class ≥F, and volume shrinkage rate ≤5% to cover the surface of the coil and the gaps between the coil turns.

4. The preparation method according to claim 1, characterized in that, The segmented curing process for the coil frame and the coil after potting includes cross-linking and curing of the potting material. The first stage of curing involves a curing temperature between 70°C and 80°C and a holding time of 60-120 minutes, which allows the potting material to undergo initial cross-linking. The second stage of curing involves a curing temperature between 95℃ and 105℃ and a holding time of 45-90 minutes to promote complete cross-linking of the potting material. The third stage of curing involves a curing temperature between 115℃ and 125℃ and a holding time of 30-60 minutes to ensure complete curing of the potting material.

5. The preparation method according to claim 1, characterized in that, After the coil frame and the coil undergo segmented curing treatment to crosslink and cure the potting material, the preparation method further includes: Post-processing is performed based on the shape of the stator teeth structure, and the post-processing includes trimming and inspection.

6. A pre-fabricated coil, manufactured using the preparation method according to any one of claims 1-5, characterized in that, include: Coil frame; The coil is wound on the coil frame; A potting layer that covers the surface of the coil and the gaps between the coil turns.

7. The prefabricated coil according to claim 6, characterized in that, The coil frame is provided with a guide cone surface and a limiting boss. The guide cone surface is used to fit with the stator teeth, and the limiting boss abuts against the coil.

8. An electric motor, characterized in that, Includes the prefabricated coil as described in claim 6 or 7.

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