Stator assembly potting method and stator assembly potting system

Abstract

This application discloses a stator assembly potting method and a stator assembly potting system. The stator assembly potting method includes: pre-treating the inner wall of a groove in the outer shell of the stator assembly to improve the bonding force between the thermally conductive resin and the inner wall of the groove; pre-coating the bottom of the groove with thermally conductive resin to form a resin underlayer; placing the iron core winding of the stator assembly into the groove to seal the groove of the outer shell to form a closed cavity; evacuating the closed cavity to achieve a preset first vacuum degree; injecting thermally conductive resin into the closed cavity in stages and applying ultrasonic vibration, while maintaining the vacuum degree of the closed cavity at a preset second vacuum degree during the potting process, until the thermally conductive resin fills the closed cavity; heating the outer shell for a preset heating time to cure the thermally conductive resin, thereby obtaining the stator assembly. This method effectively solves the problems of insufficient thermally conductive resin wetting and easy formation of local hot spots by air bubbles in traditional negative pressure potting, improving the potting quality, thermal conductivity, and structural reliability of the stator assembly.

Description

Technical Field

[0001] This application belongs to the field of stator assembly potting technology, and particularly relates to a stator assembly potting method and a stator assembly potting system. Background Technology

[0002] Stator assembly potting generally uses negative pressure potting, but because the winding structure is complex and the gaps between turns are small, it is difficult for the thermally conductive resin to fully impregnate and fill the gaps to form a thermally conductive layer. In addition, air bubbles are easily trapped during potting, forming local hot spots and affecting the quality of the final product. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a stator assembly potting method and a stator assembly potting system, which enables the thermally conductive resin to fully impregnate the iron core winding, reduce the generation of air bubbles, and improve the quality of the finished product.

[0004] In a first aspect, this application provides a stator assembly potting method, comprising: The inner wall of the groove in the stator assembly housing is pretreated to improve the bonding force between the thermally conductive resin and the inner wall of the groove. A thermally conductive resin is pre-coated at the bottom of the groove to form a resin underlayer; The stator core winding is placed into the groove, and the groove of the outer shell is sealed to form a closed cavity; Evacuate the sealed cavity to achieve the preset first vacuum level. Inject thermally conductive resin into the sealed cavity in stages and apply ultrasonic vibration, and maintain the vacuum degree of the sealed cavity at a preset second vacuum degree during the potting process until the thermally conductive resin fills the sealed cavity. The outer casing is heated for a preset heating time to allow the thermally conductive resin to cure, thus obtaining the stator assembly.

[0005] According to the stator assembly potting method of this application, the bonding force between the resin and the shell is enhanced by pretreatment, the bottom filling dead corner is eliminated by the bottom resin bottom layer, the air inside the cavity and winding is removed in advance by sealing and vacuuming, the resin is fully impregnated and the air bubbles are broken by multiple injections combined with ultrasonic vibration, the formation of pores is further suppressed by the full vacuum environment, and finally the stable and reliable potting structure is formed by heating and curing. This method can effectively solve the problems of insufficient impregnation of thermally conductive resin and easy encapsulation of air bubbles to form local hot spots in traditional negative pressure potting, and significantly improve the potting quality, thermal conductivity and structural reliability of the stator assembly.

[0006] According to one embodiment of this application, the step of injecting thermally conductive resin into a sealed cavity in stages and applying ultrasonic vibration until the sealed cavity is filled with thermally conductive resin includes: Inject thermally conductive resin into the sealed cavity and simultaneously apply ultrasonic vibration in a direction perpendicular to the bottom of the tank; Stop injecting the thermally conductive resin and apply ultrasonic vibration along the direction parallel to the bottom of the tank to maintain the preset vibration time; Repeat the above injection and vibration steps N times until the thermally conductive resin fills the sealed cavity, where N is a positive integer.

[0007] According to one embodiment of this application, the amount of thermally conductive resin injected in each repeated injection decreases sequentially; or... The first injection of thermally conductive resin into the sealed cavity is the largest amount, and the amount of thermally conductive resin injected into the sealed cavity in each subsequent injection is the same.

[0008] According to one embodiment of this application, the injection rate of the thermally conductive resin is 0.5 ml / s to 2 ml / s; and / or, The preset vibration duration is 3s~5s.

[0009] According to one embodiment of this application, the step of heating the outer casing and maintaining the heating for a preset duration includes: A preset pressure is applied to the closed cavity through the injection nozzle; A heating medium is introduced into the heating channel of the outer shell; Acquire temperature signals from multiple temperature measurement points on the outer casing; When the temperature difference between multiple temperature signals exceeds the temperature difference threshold, the flow rate of the heating medium is increased, or the temperature of the heating medium is increased, so that the temperature difference between the multiple temperature signals is less than the temperature difference threshold and the preset heating time is maintained.

[0010] According to one embodiment of this application, the preset pressure is 0.05 MPa to 0.1 MPa; and / or, The preset temperature difference is 5℃; and / or, The temperature of the heating medium is 50℃~85℃; and / or, The preset heating time is 1 hour to 5 hours.

[0011] According to one embodiment of this application, the preset first vacuum degree is -0.07MPa to -0.09MPa; and / or, The preset second vacuum level is -0.06MPa to -0.08MPa.

[0012] According to one embodiment of this application, the step of pre-coating the bottom of the groove with thermally conductive resin to form a resin underlayer includes: While coating the bottom of the groove with thermally conductive resin, ultrasonic vibration is applied in a direction perpendicular to the bottom of the groove to mechanically anchor the thermally conductive resin to the bottom of the groove, thereby forming a resin underlayer.

[0013] According to one embodiment of this application, the step of pre-treating the inner wall of the groove of the outer casing includes: First cleaning of the inner wall of the groove; Shot peening the inner wall of the groove; A second cleaning of the inner wall of the groove; Plasma treatment of the inner wall of the groove; Coupling agent treatment on the inner wall of the groove.

[0014] In a second aspect, this application provides a stator assembly potting system for implementing the stator assembly potting method of any of the technical solutions in the first aspect, the stator assembly potting system comprising: An ultrasonic vibration table has a support surface for supporting the housing. The ultrasonic vibration table can apply ultrasonic vibration in multiple directions. The ultrasonic vibration table is used to inject thermally conductive resin into a closed cavity in stages and apply ultrasonic vibration. The potting device has a potting nozzle that can output thermally conductive resin. The potting nozzle is used to connect to the potting port of a closed cavity and to inject thermally conductive resin into the closed cavity in stages. The heating device has an output end that can output a heating medium. The heating device is used to heat the outer shell for a preset heating time. The vacuum pumping device is connected to the exhaust port of the upper mold through a pipe. The vacuum pumping device is used to evacuate the closed cavity. The control device is electrically connected to the ultrasonic vibration table, the potting device, the heating device, and the vacuum pumping device, respectively.

[0015] The beneficial effects of the stator assembly potting system provided in the second aspect of this application are the same as those of the stator assembly potting method provided in the first aspect, and will not be repeated here.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a simplified structural diagram of the axial flux motor provided in the embodiments of this application; Figure 2 This is a schematic flowchart of the stator assembly potting method provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the housing of the stator assembly provided in the embodiments of this application; Figure 4 This is a partial structural schematic diagram of the stator assembly potting system provided in an embodiment of this application; Figure 5 This is a partial cross-sectional structural diagram of the stator assembly potting process provided in the embodiments of this application; Figure 6 This is a schematic diagram of the local microstructure during the process of pre-coating the bottom of the groove with thermally conductive resin, as provided in an embodiment of this application.

[0018] Figure label: 100. Stator assembly; 110. Housing; 111. Groove; 120. Iron core winding; 200. Rotor; 300. Upper mold cover plate; 310. Filling port; 320. Exhaust port; 400. Resin base layer; 500. Ultrasonic vibration table; 600. Filling nozzle. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0020] The following is for reference. Figures 1-6 This application describes a stator assembly potting method and a stator assembly potting system according to embodiments of the present application.

[0021] This application provides a stator assembly potting method.

[0022] First, it should be noted that, as Figure 1 As shown, the stator assembly 100 in this application is an axial flux motor stator assembly 100. This stator assembly 100 can adopt either a structure with a yoke or a structure without a yoke. Compared with conventional radial flux motors, the flux path of the axial flux motor extends along the axial direction of the motor. Its stator and rotor 200 are arranged opposite each other along the axial direction and form an axial air gap. The rotor 200 usually adopts a disc structure, and the stator core winding 120 is also arranged in a disc shape. The whole motor has the characteristics of compact axial dimensions, high power density, high torque density, and short heat dissipation path, making it more suitable for application scenarios with high requirements for installation space and heat dissipation performance.

[0023] Please see Figure 2 The stator assembly potting method includes steps S1, S2, S3, S4, S5 and S6.

[0024] Step S1: Pre-treat the inner wall of the groove 111 of the outer shell 110 of the stator assembly 100 to improve the bonding force between the thermally conductive resin and the inner wall of the groove 111.

[0025] Please see Figure 3In step S1, the outer shell 110 is the outer shell 110 used for the stator of the axial flux motor, and the groove 111 is used to accommodate the iron core winding 120. The pretreatment of the inner wall of the groove 111 can be physical polishing, plasma activation treatment or solvent degreasing treatment. Physical polishing can make the inner wall of the groove 111 form a micro-rough surface, increasing the contact area between the thermally conductive resin and the outer shell 110. Plasma activation treatment can remove the weak bonding layer such as oil stains and dust attached to the inner wall. Solvent degreasing treatment can remove the processing aids remaining on the inner wall. The above treatment methods can effectively improve the bonding strength between the thermally conductive resin and the outer shell 110, and avoid delamination and debonding after potting.

[0026] Step S2: Pre-coat the bottom of the groove 111 with thermally conductive resin to form a resin underlayer 400.

[0027] Please see Figure 4 and Figure 5 In step S2, the resin underlayer 400 uses the same thermally conductive resin as the subsequent potting. The coating method can be manual brushing, automatic dispensing, or low-pressure spraying. After coating, a continuous and uniform thin layer structure is formed. The resin underlayer 400 can pre-fill the tiny pits at the bottom of the slot and the tiny gaps at the contact position between the end of the iron core winding 120 and the bottom of the slot, avoiding the formation of dead corners that are difficult to fill during subsequent overall potting. At the same time, it provides preliminary positioning support for the iron core winding 120 and reduces the offset when the winding is inserted.

[0028] Step S3: Place the iron core winding 120 of the stator assembly 100 into the groove 111 and close the groove 111 of the outer shell 110 to form a closed cavity.

[0029] In step S3, the core winding 120 is a disc winding structure of an axial flux motor. After being placed into the groove 111, a uniform gap is left between it and the inner wall of the groove 111. This gap is used to fill the thermally conductive resin to achieve insulation and heat conduction. The groove 111 can be sealed by a rigid cover plate with bolts or by a special tooling mold. The sealed cavity formed after sealing has no obvious leakage gaps, which can ensure the sealing of the subsequent vacuuming and potting process and prevent external air from seeping in or thermally conductive resin from leaking out. In the following description, the sealing of the groove 111 by the upper mold cover plate 300 to form a sealed cavity is taken as an example.

[0030] Step S4: Evacuate the sealed cavity to achieve the preset first vacuum level.

[0031] Please see Figure 4 and Figure 5In step S4, the vacuuming operation is achieved through an external vacuum pump and vacuum pipeline. In some examples, the vacuum pipeline can be connected to the exhaust port 320 on the upper mold cover plate 300 for vacuuming. The vacuuming process can be carried out slowly to avoid airflow disturbances from damaging the core winding 120. The preset first vacuum level is determined based on the winding density and resin flowability. This step can expel the air inside the sealed cavity and the gas trapped between turns and layers of the core winding 120, significantly reducing the basic conditions for bubble generation during subsequent potting.

[0032] Step S5: Inject thermally conductive resin into the sealed cavity in stages and apply ultrasonic vibration, and maintain the vacuum degree of the sealed cavity at the preset second vacuum degree during the potting process until the thermally conductive resin fills the sealed cavity.

[0033] Please see Figure 5 , Figure 5 The double-headed arrows indicate the direction of ultrasonic vibration. In step S5, the number of injections of the thermally conductive resin is not specifically limited; it can be set to two, three, four, or more times. For example, when set to three times, the resin can be injected sequentially according to the winding height, from the lower part to the middle and upper part, gradually achieving complete impregnation. Ultrasonic vibration is applied through an ultrasonic vibration device attached to the outer wall of the housing 110 or the upper mold cover plate 300. Ultrasonic vibration can cause the thermally conductive resin to generate high-frequency micro-amplitude flow, breaking up tiny air bubbles trapped inside the resin, and simultaneously pushing the resin into the narrow gaps between the winding turns, improving the impregnation effect. The preset second vacuum degree remains stable throughout the potting process, continuously expelling newly generated gas during the injection process, further improving the potting density.

[0034] Step S6: Heat the outer casing 110 for a preset heating time to cure the thermally conductive resin and obtain the stator assembly 100.

[0035] In step S6, the heating method can be constant temperature heating in an oven, conduction heating from a bottom heating plate, or infrared radiation heating. The heating temperature and preset heating time can be set according to the curing curve of the thermally conductive resin used. During the heating process, the thermally conductive resin gradually changes from a fluid state to a solid curing layer, firmly bonding the iron core winding 120 and the outer shell 110 into one piece.

[0036] It is understandable that in step S6, after the thermally conductive resin has cured, the upper mold cover plate 300 can be separated by removing the bolts connecting the upper mold cover plate 300 to the stator housing 110, thereby obtaining the housing 110, the iron core winding 120, and the stator assembly 100 formed by the cured thermally conductive resin; or, in another example, when potting with a benchtop potting fixture, the potting fixture can be lifted to complete the separation.

[0037] According to the stator assembly potting method provided in this application embodiment, the bonding force between the resin and the housing 110 is enhanced through pretreatment, the bottom filling dead corner is eliminated through the bottom resin bottom layer 400, the air inside the cavity and winding is removed in advance by sealing and vacuuming, the resin is fully impregnated and air bubbles are broken through multiple injections combined with ultrasonic vibration, the formation of pores is further suppressed by the full vacuum environment, and finally, a stable and reliable potting structure is formed by heating and curing. This method can effectively solve the problems of insufficient impregnation of thermally conductive resin and easy encapsulation of air bubbles to form local hot spots in traditional negative pressure potting, and significantly improve the potting quality, thermal conductivity and structural reliability of stator assembly 100.

[0038] According to some embodiments of this application, step S5, which involves injecting thermally conductive resin into the sealed cavity in stages and applying ultrasonic vibration until the thermally conductive resin fills the sealed cavity, may include steps S51, S52, and S53.

[0039] Step S51: Inject thermally conductive resin into the sealed cavity and simultaneously apply ultrasonic vibration along the direction perpendicular to the bottom of the tank.

[0040] In step S51, while injecting thermally conductive resin into the closed cavity, ultrasonic vibration is simultaneously applied in a direction perpendicular to the bottom of the groove. This ultrasonic vibration is transmitted towards the bottom of the groove 111, driving the thermally conductive resin to flow rapidly downwards axially. This ensures the resin preferentially reaches the bottom of the groove 111 and the area of ​​the iron core winding 120 near the bottom of the groove, preventing the resin from accumulating only on the upper part of the winding during injection and failing to quickly sink to the bottom, thus ensuring the bottom area is promptly wetted by the resin. The ultrasonic vibration perpendicular to the bottom of the groove can be achieved by an ultrasonic vibration unit arranged at the bottom of the outer shell 110 or on the outside of the cover plate. The vibration direction is perpendicular to the plane where the groove bottom is located, and the vibration parameters are matched according to the resin viscosity and the winding gap size.

[0041] Step S52: Stop injecting thermally conductive resin and apply ultrasonic vibration along the direction parallel to the bottom of the tank to maintain the preset vibration time.

[0042] In step S52, the injection of thermally conductive resin is stopped, and ultrasonic vibration is applied parallel to the bottom of the groove. This vibration direction is parallel to the plane where the bottom of the groove 111 is located, which can generate high-frequency disturbance in the horizontal direction of the thermally conductive resin, causing the resin to diffuse and fill the lateral spaces such as the small gaps between the turns of the insulating coil and the side gaps of the winding, solving the problem that simple axial flow is not enough to fully penetrate into the tiny gaps. The preset vibration time is determined by calculation and practice based on factors such as the winding density and gap size of the stator winding. This time is sufficient to allow the resin to complete the lateral full impregnation under ultrasonic action, while expelling the tiny air bubbles entrained in the process. The ultrasonic vibration parallel to the bottom of the groove can be achieved by ultrasonic vibration units arranged on the side wall of the outer shell 110, or by adjusting the vibration direction of the same ultrasonic vibration device. The switching between the two vibration directions can be completed automatically, improving the continuity of the potting process.

[0043] Step S53: Repeat the above injection and vibration steps N times until the thermally conductive resin fills the closed cavity, where N is a positive integer.

[0044] In step S53, the above injection and vibration steps are repeated N times, where N is a positive integer and its specific value is not limited; it can be 2 times, 3 times, or more times. When N is 2, axial injection vibration, lateral pressure holding vibration, axial injection vibration again, and lateral pressure holding vibration again are performed sequentially. Through multiple cycles, the filling density is gradually increased. The larger the value of N, the more suitable it is for stator assemblies 100 with more complex winding structures, larger sizes, and finer gaps, enabling layer-by-layer impregnation and venting. By repeatedly applying ultrasonic vibrations in different directions and combining them with staged injection, the problems of uneven local filling and air bubble retention caused by single injection can be avoided, ensuring that the thermally conductive resin is fully filled in both the axial and lateral directions.

[0045] It should be noted that the frequency of ultrasonic vibration applied each time can be the same or different, and the amount of thermally conductive resin injected each time can be the same or different, depending on the actual needs, and there is no specific limitation.

[0046] By using alternating vibration and multiple injections, the thermally conductive resin can be guided to fill the bottom space downwards first, and then penetrate laterally into the gaps between coil turns. After multiple cycles, the entire cavity is filled without dead corners, further reducing the generation of air bubbles and significantly improving the wetting effect of the thermally conductive resin on the 120mm core winding, thereby enhancing the overall thermal conductivity and structural stability of the stator assembly after potting.

[0047] This application provides two selectable dispensing volume control modes to adapt to the potting requirements of different winding densities and cavity spaces: In some embodiments, the amount of thermally conductive resin injected in each re-injection decreases sequentially.

[0048] As the number of injections increases, the volume of thermally conductive resin injected in each subsequent injection gradually decreases. The first injection is the largest in the entire potting process, used to quickly occupy the main space in the sealed cavity and initially cover most of the 120° area of ​​the iron core winding. The second injection is slightly smaller than the first, used to fill the remaining space not filled after the previous injection. The third and subsequent injections continue to decrease in volume, mainly used to finely fill the small gaps between winding turns and corners, gradually approaching a completely filled state. This progressively decreasing injection method can avoid the resin from not flowing in time and trapping air due to excessive single injection volume. At the same time, the alternating ultrasonic vibration allows even a small amount of resin to fully penetrate into the fine areas under the action of vibration.

[0049] In other embodiments, the amount of thermally conductive resin injected into the sealed cavity is the largest in the first injection, and the amount of thermally conductive resin injected into the sealed cavity is the same in each subsequent injection.

[0050] The first injection of a large amount of thermally conductive resin quickly fills the lower part of the sealed cavity and the main body of the 120mm core winding, significantly shortening the overall potting cycle. Subsequent repeated injections use the same and smaller fixed amount of resin to replenish the filling layer by layer, gradually raise the resin level and remove residual air bubbles. This method can ensure the efficiency of the initial injection and achieve stable and controllable fine filling in the later stage by injecting small amounts of resin in equal quantities, which facilitates the standardization of process parameters and automated control.

[0051] It should be noted that the total amount of thermally conductive resin injected and the amount of thermally conductive resin injected each time can be precisely calculated to facilitate automated control during the potting process and ensure the uniformity of the finished product; alternatively, it can be observed through the vent 320. When the thermally conductive resin overflows from the vent 320, it can be determined that the sealed cavity is full.

[0052] Both of the above-mentioned glue distribution methods are combined with directional ultrasonic vibration. Under the vibration action perpendicular to the bottom of the tank, the resin is guided to fill downwards, and then the gap between the turns is filled by vibration parallel to the bottom of the tank. Reasonable glue distribution can further avoid problems such as resin accumulation and air bubble retention, making the potting process more stable and the thermally conductive resin filling more uniform and dense.

[0053] In some embodiments, the injection rate of the thermally conductive resin can be 0.5 ml / s to 2 ml / s.

[0054] The injection speed of the thermally conductive resin is controlled within the range of 0.5 ml / s to 2 ml / s. This injection speed balances potting efficiency and resin flow stability. When the injection speed is 0.5 ml / s, the resin injection is relatively smooth, effectively avoiding the formation of a large number of air bubbles in the winding gaps due to excessive flow rate. This is suitable for potting stator assemblies with dense windings and small gaps. When the injection speed is 2 ml / s, it can improve potting efficiency while ensuring stable resin filling. This is suitable for stator assemblies with relatively large gaps and slightly larger potting cavity volumes. The injection speed can also be selected from the middle value within this range, such as 1 ml / s or 1.5 ml / s, to adapt to the viscosity characteristics of different types of thermally conductive resins. This injection speed, combined with the second vacuum maintained in the sealed cavity and ultrasonic vibration, ensures smooth resin flow during injection and minimizes the formation of cavitation.

[0055] In some embodiments, the preset vibration duration can be 3s to 5s.

[0056] The preset vibration duration is set to 3 to 5 seconds. This duration refers to the duration of ultrasonic vibration applied parallel to the bottom of the groove after the resin injection stops. This ensures that the resin fully penetrates the gaps between the insulated coil turns while avoiding resin delamination or localized overheating caused by excessively long vibration times. A preset vibration duration of 3 seconds can meet the wetting and venting requirements of winding structures with relatively loose gaps, resulting in a shorter overall potting cycle. A preset vibration duration of 5 seconds provides sufficient vibration diffusion time for windings with tight windings and many small gaps, allowing the resin to fully fill every tiny gap. Intermediate durations such as 3.5 seconds, 4 seconds, or 4.5 seconds can also be selected based on the actual stator structure. After each resin injection, transverse ultrasonic vibration of this duration effectively breaks up tiny air bubbles in the resin, improves the inter-turn filling density, and creates a more adequate filling foundation for the next resin injection.

[0057] According to some embodiments of this application, step S6, which involves heating the outer casing 110 and maintaining the heating for a preset duration, may include steps S61, S62, S63, and S64.

[0058] Step S61: Apply a preset pressure to the closed cavity through the injection nozzle.

[0059] In step S61, the injection nozzle is used to inject thermally conductive resin into the closed cavity. In some examples, the injection nozzle can be connected to the filling port 310 on the upper mold cover plate 300 for easy injection. A preset pressure is applied to the closed cavity through the injection nozzle. This preset pressure is a gentle positive pressure, which can prevent the resin from creating internal voids due to volume shrinkage during heating, and can further crush and expel residual micro-air bubbles, while ensuring a continuous and tight fit between the resin and the inner wall of the groove 111 and the iron core winding 120. The pressure can be applied by air pressurization or a resin pressurization device. The pressure is set according to the cavity volume and resin viscosity to ensure that the winding insulation layer is not damaged.

[0060] Step S62: Introduce a heating medium into the heating channel of the outer shell 110.

[0061] In step S62, a heating medium is introduced into the heating channel of the outer shell 110. The heating channel can be an annular channel, a spiral channel, or a multi-branched channel formed inside the outer shell 110. The heating channel is arranged around the groove 111 area of ​​the outer shell 110 to ensure uniform heat transfer. The heating medium can be high-temperature oil, hot water, or hot air. The medium is supplied through an external temperature control circulation device, which can stably output the set temperature. The heating medium flows continuously in the heating channel to achieve uniform conductive heating of the outer shell 110, avoiding localized direct baking that could lead to resin overheating and aging or uneven curing.

[0062] Step S63: Obtain temperature signals from multiple temperature measuring points on the outer casing 110.

[0063] In step S63, temperature signals from multiple temperature measuring points on the outer casing 110 are acquired. The number of temperature measuring points is not specifically limited; two, three, four, or more can be set. With two points, because the outer side of the outer casing 110 dissipates heat quickly, a temperature gradient is easily formed from the outside to the inside of the outer casing 110. The two measuring points can be arranged on the outer side and the middle of the outer casing 110, respectively. With three points, they can be evenly distributed along the circumference of the groove 111. With four or more points, the bottom area, sidewall area, central area, and corner areas can be further covered, thus comprehensively reflecting the real-time temperature at different locations on the outer casing 110. Temperature measurement and signal transmission can be achieved using temperature sensors. Each measuring point can use a patch-type temperature sensor, which is attached tightly to the outer wall of the outer casing 110 or embedded inside the outer casing 110 to ensure accurate and reliable temperature acquisition.

[0064] Step S64: When the temperature difference between multiple temperature signals exceeds the temperature difference threshold, control the flow rate of the heating medium to increase, or control the temperature of the heating medium to increase, so that the temperature difference between multiple temperature signals is less than the temperature difference threshold and maintains the preset heating time.

[0065] In step S64, the temperature difference threshold is a preset allowable temperature deviation value. When the temperature difference between different temperature measuring points is too large, it indicates that there is uneven heating in some areas of the outer shell 110. At this time, increasing the flow rate of the heating medium can enhance the convective heat transfer efficiency and accelerate the heating rate of the low-temperature area. Increasing the temperature of the heating medium can increase the overall heating intensity and quickly reduce the regional temperature difference. After the temperature difference is controlled within the threshold, the preset heating time is maintained to ensure that the thermally conductive resin completes the curing reaction synchronously in a uniform temperature field, avoiding problems such as inconsistent curing degree, excessive internal stress, or cracking caused by local temperature differences.

[0066] In some embodiments, the preset pressure can be 0.05MPa to 0.1MPa. This pressure range is a mild pressurization range, which can continuously compress the resin to fill the shrinkage gap, crush and expel residual micro air bubbles during the resin heating, softening, flowing and curing process, without causing damage to the winding insulation layer or failure of the sealing structure of the outer shell 110 due to excessive pressure. When the pressure is 0.05MPa, it is suitable for stator assembly 100 with relatively low insulation strength. When the pressure is 0.1MPa, it is suitable for stator assembly 100 with higher structural strength and requiring higher potting density. Intermediate pressure values ​​in this range, such as 0.06MPa, 0.07MPa, 0.08MPa or 0.09MPa, can also be selected according to the resin type.

[0067] In some embodiments, the preset temperature difference can be 5°C. This value is the maximum allowable temperature difference between multiple temperature measuring points on the outer shell 110. It serves as the judgment threshold for temperature control adjustment. When the temperature difference between each temperature measuring point is controlled within 5°C, it can be considered that the external heat of the sealed cavity is uniform, which can ensure that the internal thermally conductive resin is cured in a nearly uniform temperature environment, avoiding problems such as localized rapid curing, internal stress, cracking of the potting layer, or bonding failure due to excessive temperature difference.

[0068] In some embodiments, the temperature of the heating medium can be 50℃~85℃. This temperature range is suitable for the low-to-medium temperature curing curves of commonly used epoxy thermally conductive resins. Excessive temperature will not cause rapid cross-linking of the resin, leading to internal porosity and cracking, nor will excessively low temperature result in an excessively long curing cycle or insufficient curing. A temperature of 50℃ represents low-temperature, slow curing, which helps reduce internal stress and is suitable for stator assemblies 100 with high precision requirements. A temperature of 85℃ can shorten the curing time while ensuring curing quality, improving production efficiency. Intermediate temperature values ​​such as 55℃, 60℃, 65℃, 70℃, 75℃, and 80℃ can also be selected according to the actual resin formulation. At this temperature, the heating medium circulates into the heating channels of the outer shell 110, achieving uniform conductive heating.

[0069] In some embodiments, the preset heating time can be 1 hour to 5 hours. The time can be flexibly selected according to the temperature of the heating medium, the resin type, and the size of the stator assembly 100. A shorter curing time can be used when the heating temperature is higher, and the time should be extended accordingly when the heating temperature is lower, to ensure that the thermally conductive resin is completely cross-linked and cured, forming a potting layer with stable structure and reliable thermal conductivity. By matching the above precise parameters, the curing process of the stator assembly after potting can be uniform and controllable, further improving the consistency and reliability of the potted product.

[0070] In some embodiments, the preset first vacuum level can be -0.07MPa to -0.09MPa. In this application, the above vacuum levels are all expressed in gauge pressure form, with standard atmospheric pressure as the reference. The magnitude of the negative value reflects the degree of negative pressure inside the cavity. The preset first vacuum level is controlled between -0.07MPa and -0.1MPa. This vacuum level is used to initially evacuate the sealed cavity in step S4, which can expel most of the air trapped inside the sealed cavity and in the gaps and interlayers of the iron core winding 120 in a short time, creating a good negative pressure foundation for subsequent potting. When the vacuum degree is -0.07MPa, the negative pressure is relatively low, and the pumping speed is faster. This is suitable for stator assemblies 100 with relatively large winding gaps and easy internal gas discharge. When the vacuum degree is -0.1MPa, the negative pressure is higher, which can more thoroughly discharge residual gas in small gaps. This is suitable for stator assemblies 100 with dense windings and many small gaps. The intermediate value in this range can also be selected according to the viscosity of the thermally conductive resin and the stator specifications, such as -0.075MPa, -0.08MPa, -0.085MPa and -0.09MPa.

[0071] It should be noted that during the vacuuming phase, the preset first vacuum level should be maintained for 1 to 3 minutes to ensure that the air inside the sealed cavity is fully evacuated. The specific time is determined based on the volume of the sealed cavity.

[0072] In some embodiments, the preset second vacuum degree can be -0.06MPa to -0.08MPa, and the preset second vacuum degree is controlled between -0.06MPa and -0.08MPa. This vacuum degree is maintained throughout the entire process of injecting thermally conductive resin in stages and applying ultrasonic vibration in step S5. Its negative pressure is slightly lower than the overlap of the first vacuum degree, which can continuously suppress the generation and growth of bubbles, and avoid problems such as excessive boiling, splashing, or abnormal flow of thermally conductive resin due to excessively high vacuum, ensuring that the injection process is stable and controllable. When the second vacuum degree is -0.06MPa, the internal pressure of the cavity is relatively higher, and the resin flow is smoother, which is suitable for thermally conductive resins with lower viscosity. When the second vacuum degree is -0.08MPa, the venting effect can be further enhanced, improving the resin's ability to fill the fine gaps in the winding, and is suitable for thermally conductive resins with higher viscosity and greater filling difficulty.

[0073] According to some embodiments of this application, step S2, which involves pre-coating the bottom of the groove 111 with thermally conductive resin to form a resin underlayer 400, may include step S21.

[0074] Step S21: While coating the bottom of the groove 111 with thermally conductive resin, apply ultrasonic vibration in a direction perpendicular to the bottom of the groove to make the thermally conductive resin mechanically anchored to the bottom of the groove, so as to form a resin bottom layer 400.

[0075] In step S2, directional ultrasonic vibration is applied simultaneously during the coating of the resin substrate 400 to enhance the bonding strength between the resin substrate 400 and the bottom of the outer casing 110. For example... Figure 6 As shown, Figure 6 The double-headed arrows indicate the direction of ultrasonic vibration. During the coating of thermally conductive resin at the bottom of groove 111, ultrasonic vibration is simultaneously applied in a direction perpendicular to the bottom of the groove. This vibration direction is directed towards the bottom surface of the groove, which can drive the liquid thermally conductive resin to generate high-frequency micro-amplitude impacts. Under the action of vibration, the resin fully penetrates into the micro-pits, textures, and fine pores formed on the pre-treated surface of the bottom of the groove. Ultrasonic vibration can also break up any tiny air bubbles that may exist in the thermally conductive resin itself, preventing pores from appearing inside the resin bottom layer 400 and ensuring a dense bottom layer structure.

[0076] As the resin penetrates the microstructure at the bottom of the tank and gradually cures, a mechanically anchored structure is formed between the thermally conductive resin and the tank bottom. This anchoring structure significantly improves the bonding force between the resin substrate 400 and the outer shell 110, preventing displacement, warping, or detachment of the resin substrate 400 during subsequent core winding 120 insertion, glue injection, and heat curing. Ultrasonic vibration perpendicular to the tank bottom can be applied by an ultrasonic vibration component located at the bottom of the outer shell 110. The vibration parameters are matched to the viscosity of the thermally conductive resin, ensuring sufficient resin flow and penetration without causing excessive resin splashing or loss.

[0077] According to some embodiments of this application, step S1, the step of pre-processing the inner wall of the groove 111 of the outer shell 110, may include: step S11, step S12, step S13, step S14 and step S15.

[0078] Step S11: First cleaning of the inner wall of groove 111.

[0079] In step S11, the inner wall of the groove 111 is cleaned for the first time. The cleaning method can be organic solvent cleaning, alkaline cleaning agent cleaning or high pressure spray cleaning. It is mainly used to remove oil stains, cutting fluid, dust and loose rust that adhere to the inner wall of the groove 111 during processing and transportation, so as to provide a clean base surface for subsequent surface treatment and avoid impurities from affecting the subsequent shot peening effect and resin bonding strength.

[0080] Step S12: Shot peening the inner wall of groove 111.

[0081] In step S12, the inner wall of the groove 111 is shot-peened. The shot-peening medium can be steel shot, glass shot, or ceramic shot. The shot-peening pressure is set appropriately according to the material and wall thickness of the outer shell 110. By impacting the inner wall surface with high-speed shot, the dense oxide layer on the aluminum surface can be removed, and a uniform and dense micro-rough morphology can be formed on the inner wall of the groove 111. At the same time, local stress on the inner wall is eliminated and slight oxide scale is removed, providing a physical basis for the subsequent formation of a mechanical interlocking structure between the thermally conductive resin and the outer shell 110, and further enhancing the interfacial bonding strength. Shot peening can cover the entire inner wall area of ​​the groove 111, or it can focus on strengthening the treatment of areas with high bonding stress, such as the bottom of the groove and corners.

[0082] Step S13: Clean the inner wall of groove 111 a second time.

[0083] In step S13, the inner wall of the groove 111 is cleaned a second time. This cleaning can be done by rinsing with deionized water, blowing with compressed air or ultrasonic cleaning. The purpose is to thoroughly remove the shot fragments, dust and abrasive impurities remaining after shot peening, to avoid solid particles remaining on the inner wall to form local weak points, and to ensure that the inner wall surface is clean and flat, so as to create conditions for subsequent plasma treatment and coupling agent treatment.

[0084] Step S14: Plasma treatment of the inner wall of groove 111.

[0085] In step S14, the inner wall of the groove 111 is subjected to plasma treatment. The plasma generates high-energy active particles under the action of an electric field. After acting on the surface of the inner wall of the groove 111, it can further remove microscopic residual organic pollutants and introduce hydroxyl active groups -OH on the surface of the inner wall of the outer shell 110, so that the inner wall surface changes from an inert state to a highly active state, significantly increasing the surface energy and providing reaction sites for subsequent chemical reactions with coupling agents.

[0086] Step S15: Treat the inner wall of groove 111 with coupling agent.

[0087] In step S15, the inner wall of the groove 111 is treated with a coupling agent. After contacting the inner wall surface, one end of the coupling agent molecule can chemically react with the hydroxyl group -OH formed by plasma treatment to achieve chemical bonding with the inner wall of the outer shell 110. The other end of the coupling agent molecule has an active group that can react with epoxy resin. During subsequent potting and heat curing, it can chemically bond with the thermally conductive epoxy resin system, thereby forming a stable molecular bridge connection between the metal outer shell 110 and the epoxy resin potting layer, achieving true chemical bonding rather than simple physical bonding.

[0088] Through the above five continuous pretreatment processes, from decontamination, roughening, and re-cleaning, to surface activation to introduce hydroxyl groups, and then to coupling agent to achieve interfacial chemical bonding, the bonding performance between the inner wall of groove 111 and thermally conductive resin is improved in multiple dimensions. This effectively avoids problems such as thermal conductivity failure, local voids and bubble formation caused by poor interfacial bonding, and provides a reliable guarantee for the potting quality of the entire stator assembly.

[0089] Please see Figure 4 Based on the same concept, this application also provides a stator assembly potting system for implementing any of the above technical solutions. The system completes the fully automated potting process from pretreatment, vacuuming, multi-stage glue injection, multi-directional ultrasonic vibration to temperature-controlled pressure curing through the coordinated cooperation of multiple functional modules.

[0090] The stator assembly potting system includes: an ultrasonic vibration table 500, a potting device, a heating device, a vacuum device, and a control device. The ultrasonic vibration table 500 has a support surface for supporting the housing 110. The ultrasonic vibration table 500 can apply ultrasonic vibrations in multiple directions and is used to inject thermally conductive resin into the sealed cavity in stages while applying ultrasonic vibrations. The potting device has a potting nozzle 600 that can output thermally conductive resin. The potting nozzle 600 is used to connect to the potting port 310 of the sealed cavity and is used to inject thermally conductive resin into the sealed cavity in stages. The output end of the heating device can output a heating medium and is used to heat the housing 110 for a preset heating time. The vacuum device is connected to the exhaust port 320 of the upper mold through a pipe and is used to evacuate the sealed cavity. The control device is electrically connected to the ultrasonic vibration table 500, the potting device, the heating device, and the vacuum device.

[0091] The ultrasonic vibration table 500 is provided with a support surface for supporting the housing 110. The support surface can be a planar structure or a contoured structure adapted to the bottom shape of the housing 110, ensuring that the housing 110 is placed stably and subjected to uniform force during potting and curing. The ultrasonic vibration table 500 can output ultrasonic vibrations in multiple directions, achieving vibrations perpendicular to the support surface or parallel to the support surface, corresponding to the steps of guiding the resin downward to fill the bottom space and promoting the resin to penetrate laterally into the gap between the coil turns in the aforementioned method. The direction, frequency, amplitude, and start / stop timing of the vibration can be switched and adjusted according to the process requirements, coordinating directional vibration for venting and impregnation during the phased injection of thermally conductive resin.

[0092] The potting device is equipped with a potting nozzle 600 capable of quantitatively dispensing thermally conductive resin. The shape of the potting nozzle 600 is adapted to the filling port 310 of the sealed cavity. The two can be sealed together by threaded connection, plug-in sealing, or flange compression to prevent air leakage or resin leakage during vacuum potting. The potting device can be equipped with resin stirring, heat preservation, and metering units, which can dispense thermally conductive resin in stages according to preset number of times and injection volume. The dispensing speed can be stably controlled within a set range to meet the dispensing requirements of 0.5ml / s to 2ml / s, achieving precise and controllable staged dispensing. The potting device also has a pressure holding function, which can apply a preset pressure of 0.05MPa to 0.1MPa to the sealed cavity through the potting nozzle 600, allowing the resin to cure under pressure.

[0093] The output end of the heating device can continuously output heating medium. The heating device can be an oil temperature controller, a water temperature controller, or a hot air circulation unit. The output heating medium temperature can be stably maintained in the range of 50℃~85℃. The heating medium is connected to the heating flow channel inside the outer shell 110 through a pipeline. During the curing stage, the closed cavity is uniformly circulated and heated. With the subsequent temperature adjustment, the temperature difference of each part of the outer shell 110 can be controlled.

[0094] The vacuum pumping device is connected to the exhaust port 320 of the upper mold through a sealed pipe. The vacuum pumping device can be a vacuum pump set or a vacuum generator, which can pump the vacuum inside the sealed cavity to a preset first vacuum level of -0.07MPa to -0.09MPa, and maintain a preset second vacuum level of -0.06MPa to -0.08MPa during the filling process. The vacuum pumping rate and vacuum level maintenance accuracy can be automatically adjusted to ensure that the gas inside the cavity is fully discharged.

[0095] The control device is electrically connected to the ultrasonic vibration table 500, the potting device, the heating device, and the vacuuming device. The control device can be a PLC controller or an industrial control computer, with a complete potting process program pre-stored inside. It can automatically control the start and stop, parameter adjustment, and action sequence of each device according to the preset process. The control device can receive temperature signals from multiple temperature measuring points on the outer casing 110. When the temperature difference between the measuring points exceeds 5°C, it automatically adjusts the medium flow rate or output temperature of the heating device to reduce the temperature difference to the allowable range and maintain the preset heating time of 1h to 5h. At the same time, it controls the vacuuming device to maintain the corresponding vacuum level, controls the potting device to inject glue in stages, and controls the ultrasonic vibration table 500 to switch the vibration direction and duration, realizing the automation and precise control of the entire potting process.

[0096] According to the potting system provided in the embodiments of this application, through the coordinated work of each component, all the processes in the aforementioned potting method can be fully realized, effectively solving problems such as insufficient resin impregnation, easy encapsulation of air bubbles, and uneven curing, thereby improving the consistency, density, and reliability of the stator assembly potting.

[0097] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0098] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0099] In the description of this application, "first feature" and "second feature" may include one or more of the features.

[0100] In the description of this application, "multiple" means two or more.

[0101] In the description of this application, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features being in contact through another feature between them.

[0102] In the description of this application, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0103] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0104] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for potting a stator assembly, characterized in that, include: The inner wall of the groove in the stator assembly housing is pretreated to improve the bonding force between the thermally conductive resin and the inner wall of the groove. A thermally conductive resin is pre-coated at the bottom of the groove to form a resin underlayer; The stator core winding is placed into the groove, and the groove of the outer shell is closed to form a closed cavity; The sealed cavity is evacuated to achieve a preset first vacuum level. Thermally conductive resin is injected into the sealed cavity in stages and ultrasonic vibration is applied. During the potting process, the vacuum degree of the sealed cavity is maintained at a preset second vacuum degree until the thermally conductive resin fills the sealed cavity. The outer casing is heated for a preset heating time to allow the thermally conductive resin to cure, thereby obtaining the stator assembly.

2. The stator assembly potting method according to claim 1, characterized in that, The step of injecting thermally conductive resin into the sealed cavity in stages and applying ultrasonic vibration until the thermally conductive resin fills the sealed cavity includes: Thermally conductive resin is injected into the sealed cavity, and ultrasonic vibration is simultaneously applied in a direction perpendicular to the bottom of the tank. Stop injecting thermally conductive resin and apply ultrasonic vibration along the direction parallel to the bottom of the tank to maintain the preset vibration time; Repeat the above injection and vibration steps N times until the thermally conductive resin fills the sealed cavity, where N is a positive integer.

3. The stator assembly potting method according to claim 2, characterized in that, The amount of thermally conductive resin injected each time decreases sequentially; or, The amount of thermally conductive resin injected into the sealed cavity is the largest during the first injection, and the amount of thermally conductive resin injected into the sealed cavity is the same in each subsequent injection.

4. The stator assembly potting method according to claim 2, characterized in that, The injection rate of the thermally conductive resin is 0.5 ml / s to 2 ml / s; and / or, The preset vibration duration is 3s to 5s.

5. The stator assembly potting method according to any one of claims 1-4, characterized in that, The step of heating the outer shell and maintaining the heating for a preset duration includes: A preset pressure is applied to the sealed cavity through the injection nozzle; A heating medium is introduced into the heating channel of the outer shell; Acquire temperature signals from multiple temperature measurement points on the outer casing; If the temperature difference between multiple temperature signals exceeds a temperature difference threshold, the flow rate of the heating medium is increased, or the temperature of the heating medium is increased, so that the temperature difference between the multiple temperature signals is less than the temperature difference threshold and the preset heating time is maintained.

6. The stator assembly potting method according to claim 5, characterized in that, The preset pressure is 0.05 MPa to 0.1 MPa; and / or, The preset temperature difference is 5°C; and / or, The temperature of the heating medium is 50℃~85℃; and / or, The preset heating time is 1h to 5h.

7. The stator assembly potting method according to any one of claims 1-4, characterized in that, The preset first vacuum level is -0.07MPa to -0.09MPa; and / or, The preset second vacuum degree is -0.06MPa to -0.08MPa.

8. The stator assembly potting method according to any one of claims 1-4, characterized in that, The step of pre-coating the bottom of the groove with thermally conductive resin to form a resin underlayer includes: While coating the bottom of the groove with thermally conductive resin, ultrasonic vibration is applied in a direction perpendicular to the bottom of the groove to mechanically anchor the thermally conductive resin to the bottom of the groove, thereby forming the resin underlayer.

9. The stator assembly potting method according to any one of claims 1-4, characterized in that, The step of pre-treating the inner wall of the groove in the outer shell includes: The inner wall of the groove is cleaned for the first time; The inner wall of the groove was shot peened. The inner wall of the groove is cleaned a second time; The inner wall of the groove is subjected to plasma treatment; The inner wall of the groove is treated with a coupling agent.

10. A stator assembly potting system for implementing the stator assembly potting method of any one of 1-9, characterized in that, include: An ultrasonic vibration table has a support surface for supporting a housing. The ultrasonic vibration table is capable of applying ultrasonic vibrations in multiple directions. The ultrasonic vibration table is used to inject thermally conductive resin into the enclosed cavity in stages and apply ultrasonic vibrations. A potting device having a potting nozzle capable of discharging thermally conductive resin, the potting nozzle being used to connect to the potting port of a closed cavity, the potting nozzle being used to inject thermally conductive resin into the closed cavity in stages; A heating device, the output of which can output a heating medium, is used to heat the outer shell for a preset heating time; A vacuum pumping device is connected to the exhaust port of the upper mold via a pipe. The vacuum pumping device is used to evacuate the closed cavity. The control device is electrically connected to the ultrasonic vibration table, the potting device, the heating device, and the vacuuming device, respectively.

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