Composite motor housing and method of processing thereof

Abstract

The application provides a composite motor shell and a processing method thereof, and relates to the technical field of motor shell processing.The composite motor shell is combined by aluminum alloy, carbon fibers and engineering plastics, has high strength and rigidity, and the added carbon fibers significantly improve the strength and impact resistance of the material.The insulating layer formed on the inner surface of the aluminum alloy inner layer can effectively isolate the current, prevent electrical short circuit and electric leakage, and thus enhance the safety of the motor.The microstructure formed on the outer surface of the aluminum alloy inner layer can improve the adhesion of the material, increase the surface area, and improve the composite effect of the subsequent carbon fiber and engineering plastic outer layer.The embedded stainless steel woven mesh between the carbon fiber middle layer and the engineering plastic outer layer enhances the overall toughness and tensile strength of the shell and suppresses the high-frequency electromagnetic interference of the motor.Therefore, the application solves the technical problem that the composite motor shell in the prior art lacks electromagnetic shielding function.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor shell processing, and in particular to a composite motor shell and a processing method thereof. BACKGROUND

[0002] With the continuous development of industrial technology, as the core component of various mechanical equipment, the performance of the motor directly affects the operation efficiency and reliability of the entire equipment. Among the many components of the motor, the motor shell plays multiple roles such as protecting the internal structure of the motor, supporting the stator and rotor of the motor, and heat dissipation.

[0003] The commonly used materials for motor shells mainly include traditional metal materials such as cast iron, aluminum alloy, and steel. Although the above-mentioned metal materials have good strength, rigidity, and heat conduction performance, they have certain limitations in terms of weight, corrosion resistance, processing difficulty, and heat dissipation performance, especially in terms of lightweight and efficient heat dissipation, which cannot meet the demand for higher performance motors.

[0004] In the prior art, composite materials are gradually applied to the research and development of motor shells due to their excellent performance and lightweight characteristics. Composite materials are usually composed of two or more materials, which can fully utilize the superior performance of each component. However, traditional composite motor shells only focus on lightweight or strength, and lack electromagnetic shielding function. Since the electromagnetic shielding ability of composite materials is weak, it is difficult to effectively prevent electromagnetic interference generated during motor operation, thereby affecting the normal operation of the motor and its surrounding equipment. SUMMARY

[0005] The present application aims to provide a composite motor shell and a processing method thereof, which solves the technical problem of the lack of electromagnetic shielding function in the prior art composite motor shell.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] According to a first aspect, the present application discloses a processing method of a composite motor shell, comprising:

[0008] Step S1: forming an aluminum alloy inner layer, processing an insulating layer on the inner surface of the aluminum alloy inner layer, and processing a microstructure on the outer surface of the aluminum alloy inner layer; wherein the aluminum alloy inner layer has a cooling channel;

[0009] Step S2: carbon fiber reinforced composite of the aluminum alloy inner layer, and curing treatment after compounding to obtain a preliminary structure; the preliminary structure includes an aluminum alloy inner layer and a carbon fiber intermediate layer;

[0010] Step S3, pre-setting a stainless steel woven mesh on the outer surface of the preliminary structure, injection molding an engineering plastic outer layer, to obtain a composite motor shell; wherein the stainless steel woven mesh is embedded between the carbon fiber intermediate layer and the engineering plastic outer layer.

[0011] Optionally, the step S1 comprises:

[0012] Step S11, adopting vacuum high-pressure die casting to form an aluminum alloy inner layer, the injection speed is controlled at 5.8-6.5 m / s, the mold temperature is maintained at 240-280℃, and a cooling sand core is integrated during the die casting process to form a double helix-shaped cooling flow channel; wherein the helix angle of the cooling flow channel is 30-40°, and the pitch is 100-150 mm;

[0013] Step S12, performing micro-arc oxidation treatment on the inner surface of the aluminum alloy inner layer to form an α-Al2O3 insulation layer with a thickness of 50-60 μm; wherein the oxidation voltage is 550-650 V, the frequency is 800-1200 Hz, and the treatment time is 45-60 minutes;

[0014] Step S13, performing surface modification treatment on the α-Al2O3 insulation layer;

[0015] Step S14, processing a honeycomb-shaped microstructure on the outer surface of the aluminum alloy inner layer through a five-axis linkage micro-milling process; wherein the unit side length of the microstructure is 1.0-1.5 mm, the depth is 0.4-0.7 mm, and the wall thickness is 0.15-0.25 mm.

[0016] Optionally, the step S13 comprises:

[0017] Step S131, after the micro-arc oxidation treatment, spin-coating ZrO2 suspension on the inner surface of the aluminum alloy inner layer, and curing in a vacuum drying oven with a drying temperature of 120-150℃ for 1-2 hours to form a ZrO2 coating layer; wherein the spin-coating rotation speed is 800-1200 rpm, and the coating thickness is 10-15 μm;

[0018] Step S132, performing laser scanning on the ZrO2 coating layer by using a fiber laser, so that the surface ZrO2 particles form metallurgical bonding with the α-Al2O3 matrix, and the cladding depth is 3-5 μm; wherein the wavelength of the fiber laser is 1064 nm, the power is 200-300 W, and the spot diameter is 50 μm;

[0019] Step S133, polishing the ZrO2 coating layer after laser scanning by a magneto-rheological finishing process to form a dense transition layer with a thickness of 2-5 μm, so that the surface roughness Ra is ≤0.1 μm; wherein the polishing process uses CeO2 abrasive with a particle size of 1-3 μm, and the polishing pressure is 0.05-0.1 MPa.

[0020] Optionally, after the step S14, the step S1 further comprises:

[0021] Step S15, sandblasting the inner wall of the cooling flow channel using Al2O3 abrasive with a particle size of 80-120 μm at a sandblasting pressure of 0.4-0.6 MPa, so that the inner wall roughness Ra of the cooling flow channel is controlled to be 0.6-1.2 μm.

[0022] Optionally, the step S2 comprises:

[0023] Step S21, using carbon fibers and epoxy resin to make a prepreg, and cutting the prepreg into a lay-up tape with a width of 50-100 mm; wherein the weight content of the epoxy resin is 35±2%;

[0024] Step S22, winding the lay-up tape on the aluminum alloy inner layer by a seven-axis fiber winding machine, and locally pressurizing in the area of the microstructure to form a carbon fiber intermediate layer; wherein the main shaft rotation speed is 10-15 rpm, the fiber tension is 70-90 N, the winding angle gradually changes from ±45° to ±75° in the axial direction, the angle increment of each turn is 0.5°, and the pressure is 0.3-0.5 MPa;

[0025] Step S23, gradient curing treatment is performed on the carbon fiber intermediate layer to obtain a preliminary structure.

[0026] Optionally, the step S23 comprises:

[0027] Step S231, first stage curing, heating at a heating rate of 1.5-2.5 ℃ / min to 80-100 ℃, and keeping the temperature for 30-40 minutes, while synchronously applying a vacuum negative pressure environment with a vacuum degree of ≤50 Pa;

[0028] Step S232, second stage curing, heating at a heating rate of 0.5-1.0 ℃ / min to 120-150 ℃, applying an equal pressure of 0.6-0.8 MPa, and maintaining for 90-120 minutes;

[0029] Step S233, third stage curing, heating at a heating rate of 3-5 ℃ / min to 170-180 ℃, increasing the pressure to 1.0-1.2 MPa, and constant temperature curing for 30-50 minutes.

[0030] Optionally, after the step S23, further comprising:

[0031] In step S24, the preliminary structure after curing is subjected to a cooling treatment, and is slowly cooled to below 60℃ at a cooling rate of 0.5℃ / min, and low-frequency vibration with a frequency of 20-40Hz is applied at a critical temperature of 80℃; wherein the acceleration is 0.5g, and the amplitude is 0.1mm.

[0032] Optionally, the step S3 comprises:

[0033] In step S31, a stainless steel woven mesh is provided, and the stainless steel woven mesh is subjected to plasma cleaning; wherein the argon flow rate is 20-30L / min, the power is 300-500W, and the cleaning time is 5-8min;

[0034] In step S32, the stainless steel woven mesh after plasma cleaning is spin-coated with an epoxy-silane coupling agent, and is pre-cured at a temperature of 150-180℃ for 30min; wherein the thickness of the epoxy-silane coupling agent is 1-3μm;

[0035] In step S33, the stainless steel woven mesh is attached to the outer surface of the carbon fiber intermediate layer using a six-axis robot, and a negative pressure of 0.1-0.3MPa is applied for adsorption and fixation;

[0036] In step S34, a gradient injection molding method is adopted, PA66-GF30 material is selected for injection molding of the engineering plastic outer layer, and the glass fiber content is 30±2wt%; the barrel temperature is set to 280-300℃, and the mold temperature is 80-100℃.

[0037] Optionally, in the step 34, the gradient injection molding pressure is specifically:

[0038] The applied pressure in the first stage is set to 80-100MPa, and 90% of the volume of the cavity 90 is filled in 2-3s to achieve high-speed injection of the plastic;

[0039] The applied pressure in the second stage is set to 40-60MPa, and lasts for 10-15s;

[0040] The applied pressure in the third stage is set to 20-30MPa to eliminate the weld line.

[0041] According to the second aspect, a composite motor shell is disclosed, which is prepared by the processing method of the composite motor shell according to the first aspect, comprising an aluminum alloy inner layer, the aluminum alloy inner layer is compounded with a carbon fiber intermediate layer, the outer surface of the carbon fiber intermediate layer is wrapped with an engineering plastic outer layer, and a stainless steel woven mesh is embedded between the carbon fiber intermediate layer and the engineering plastic outer layer;

[0042] The inner surface of the aluminum alloy inner layer is provided with an insulating layer, the outer surface of the aluminum alloy inner layer is provided with a microstructure, and the aluminum alloy inner layer has a cooling flow channel.

[0043] Compared with the prior art, the present application has the following beneficial effects:

[0044] The processing method of the composite motor shell provided by the present application combines aluminum alloy, carbon fiber and engineering plastic, and the composite motor shell has high strength and rigidity. The added carbon fiber significantly improves the strength and impact resistance of the material. The insulating layer formed on the inner surface of the aluminum alloy inner layer can effectively isolate the current and prevent electrical short circuit and leakage, thereby enhancing the safety of the motor. The microstructure formed on the outer surface of the aluminum alloy inner layer can improve the adhesion of the material, increase the surface area and improve the compounding effect of the subsequent carbon fiber and engineering plastic outer layer. The cooling flow channel arranged in the aluminum alloy inner layer can effectively discharge the heat generated during the operation of the motor in time, thereby enhancing the heat dissipation effect. The stainless steel woven mesh embedded between the carbon fiber intermediate layer and the engineering plastic outer layer enhances the overall toughness and tensile strength of the shell and suppresses the high-frequency electromagnetic interference of the motor. Therefore, the present application solves the technical problem of the lack of electromagnetic shielding function of the composite motor shell in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0046] The structures, proportions, sizes, etc. shown in the drawings of the present specification are only used to cooperate with the content disclosed in the specification, to enable those skilled in the art to understand and read, and are not used to limit the defined conditions under which the present application can be implemented, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, which does not affect the effects that can be produced by the present application and the purposes that can be achieved, should still fall within the scope of the technical content disclosed by the present application.

[0047] Figure 1 A flowchart of the processing method of the composite motor shell provided by the present application is provided. DETAILED DESCRIPTION

[0048] In order to make the inventive purposes, features and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work under the premise of the present application, all belong to the scope of protection of the present application.

[0049] In the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there can be a component disposed therebetween.

[0050] The technical solutions of the present application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0051] Embodiment one:

[0052] The embodiment of the present application provides a processing method of a composite motor shell, comprising:

[0053] Step S1, forming an aluminum alloy inner layer, processing an insulating layer on the inner surface of the aluminum alloy inner layer, and processing a microstructure on the outer surface of the aluminum alloy inner layer; wherein the aluminum alloy inner layer has a cooling channel. In this embodiment, the aluminum alloy inner layer can be made by pressure casting or injection molding known in the art, which will not be described here.

[0054] In an embodiment, step S1 comprises:

[0055] Step S11, an aluminum alloy inner layer is formed by vacuum high-pressure die casting, the injection speed is controlled at 5.8-6.5 m / s, the mold temperature is kept at 240-280℃, and an integrated conformal cooling sand core is formed during the die casting process to form a double helix cooling channel; wherein the helix angle of the cooling channel is 30-40°, and the pitch is 100-150 mm; in this embodiment, the aluminum alloy inner layer is prepared by a commonly used die casting equipment. The conformal cooling sand core is an internal cooling structure made of sand (usually ceramic sand or other high-temperature resistant sand), which can be manufactured according to the shape of the casting. The design of the conformal cooling sand core can match the geometry of the casting, thereby achieving more efficient cooling. Through the setting of the conformal cooling sand core, the cooling medium (such as water or other cooling liquid) is allowed to flow inside the casting, thereby increasing the cooling surface area and accelerating the cooling speed, ensuring uniform cooling of the casting during solidification, and reducing the risk of thermal stress and deformation.

[0056] Step S12, a micro-arc oxidation treatment is performed on the inner surface of the aluminum alloy inner layer by using a micro-arc oxidation treatment equipment to form an α-Al2O3 insulation layer with a thickness of 50-60 μm; wherein the oxidation voltage is 550-650 V, the frequency is 800-1200 Hz, and the treatment time is 45-60 minutes; in this embodiment, the micro-arc oxidation treatment equipment is a commonly known equipment in the art, which will not be described here. The current density is 8-12 A / dm 2 , and the electrolyte formula is: 10 g / L sodium silicate, 5 g / L sodium dihydrogen phosphate, and potassium hydroxide with pH = 11-12; the electrolyte temperature is 20-30℃.

[0057] Step S13, the α-Al2O3 insulation layer is subjected to surface modification treatment.

[0058] Step S14, a honeycomb-shaped microstructure is machined on the outer surface of the aluminum alloy inner layer by a five-axis linkage micro-milling process; wherein the unit side length of the microstructure is 1.0-1.5 mm, the depth is 0.4-0.7 mm, and the wall thickness is 0.15-0.25 mm; a diamond-coated milling cutter with a diameter of 0.3 mm is selected as the machining tool, the rotation speed is 40,000-50,000 rpm, and the feed speed is 120-180 mm / min; the five-axis linkage micro-milling process is a commonly known process, which will not be described here.

[0059] Step S15, the inner wall of the cooling channel is subjected to sandblasting treatment by a sandblasting equipment, Al2O3 abrasive with a particle size of 80-120 μm is used, and the sandblasting pressure is 0.4-0.6 MPa, so that the inner wall roughness Ra of the cooling channel is controlled at 0.6-1.2 μm. The sandblasting equipment is a commonly known equipment in the art, which will not be described here.

[0060] It should be noted that in step S11, by vacuum high-pressure die casting technology, the bubbles and defects in the aluminum alloy inner layer can be effectively reduced, and the compactness and mechanical properties of the aluminum alloy can be improved; the double helical cooling channel integrated in the die casting process can optimize the cooling process of the aluminum alloy, help to reduce the thermal stress, improve the internal homogeneity of the casting, prevent deformation, and effectively improve the heat dissipation efficiency. In step S12, the α-Al2O3 insulation layer formed by the micro-arc oxidation technology has excellent insulation performance and chemical stability, which can effectively prolong the service life of the motor and reduce the risk of electric leakage. In step S13, by surface modification treatment of the α-Al2O3 insulation layer, the adhesion and wear resistance of the insulation layer are enhanced, the performance of the overall motor shell is improved, and the electrical insulation performance can be maintained well under long time and extreme conditions. In step S14, the honeycomb microstructure can increase the surface area of the aluminum alloy inner layer, enhance the adhesion performance of the carbon fiber in step S2 and the engineering plastic in step S3, and help to improve the interfacial strength between the composite materials. In step S15, by sandblasting treatment of the inner wall of the cooling channel, the roughness can be controlled, and the surface of the cooling channel can be in better contact with the cooling liquid, thereby improving the heat transfer efficiency.

[0061] Specifically, step S13 comprises:

[0062] Step S131, a ZrO2 suspension solution is spin-coated on the inner surface of the aluminum alloy inner layer after micro-arc oxidation treatment by a spin coating device, and is cured in a vacuum drying box with a drying temperature of 120-150℃ for 1-2 hours to form a ZrO2 coating layer; wherein the spin coating speed is 800-1200 rpm, and the coating thickness is 10-15 μm;

[0063] Step S132, a fiber laser is used to perform laser scanning on the ZrO2 coating layer, so that the surface ZrO2 particles form a metallurgical bond with the α-Al2O3 matrix, and the cladding depth is 3-5 μm; wherein the wavelength of the fiber laser is 1064 nm, the power is 200-300 W, and the spot diameter is 50 μm;

[0064] Step S133, the ZrO2 coating layer after laser scanning is polished by a magnetorheological polishing process to form a densified transition layer with a thickness of 2-5 μm, so that the surface roughness Ra≤0.1 μm; wherein the polishing process uses CeO2 abrasive with a particle size of 1-3 μm, and the polishing pressure is 0.05-0.1 MPa. The magnetorheological polishing process is a known process in the art, which will not be described here.

[0065] It should be noted that in step S131, by spin-coating ZrO2 suspension on the inner surface of the inner layer of the aluminum alloy after micro-arc oxidation treatment, a uniform ZrO2 coating layer can be formed. ZrO2 has excellent insulation, wear resistance and high temperature resistance, further enhancing the electrical performance and durability of the insulation layer. In step S132, by using a fiber laser to scan the ZrO2 coating layer, the ZrO2 particles can form a metallurgical bond with the α-Al2O3 matrix, improving the interlayer bonding strength and preventing the coating from peeling off. At the same time, the microstructure of the ZrO2 coating layer is also optimized, making it more stable under high temperature and high voltage conditions. In step S133, the ZrO2 coating layer after laser treatment is polished using a magneto-rheological polishing process, which can form a dense transition layer with a thickness of 2-5 μm, significantly improving the smoothness of the surface and making the roughness Ra≤0.1 μm, ensuring the smooth surface of the insulation layer and reducing the probability of surface defects. By using CeO2 abrasive with a particle size of 1-3 μm and controlling the polishing pressure, the surface treatment effect can be finely adjusted.

[0066] In an embodiment, step S2, carbon fiber reinforced composite is carried out on the aluminum alloy inner layer, and after the composite is cured, a preliminary structure is obtained; the preliminary structure includes the aluminum alloy inner layer and the carbon fiber intermediate layer.

[0067] Specifically, step S2 includes:

[0068] Step S21, a prepreg is made of carbon fiber and epoxy resin, and the prepreg is cut into a laying tape with a width of 50-100 mm; wherein the weight content of epoxy resin is 35±2%;

[0069] Step S22, the laying tape is wound on the aluminum alloy inner layer by a seven-axis fiber winding machine, and local pressure is applied in the microstructure area to form a carbon fiber intermediate layer; wherein the main shaft speed is 10-15 rpm, the fiber tension is 70-90 N, the winding angle gradually changes from ±45° to ±75° according to the axial direction, the angle increment of each circle is 0.5°, and the pressure is 0.3-0.5 MPa; in this embodiment, too high fiber tension (>100 N) will cause fiber breakage, and too low fiber tension (<50 N) will cause interlayer porosity >5%.

[0070] Step S23, the carbon fiber intermediate layer is subjected to gradient curing treatment by a curing box to obtain a preliminary structure;

[0071] Step S24, the cooled preliminary structure is subjected to temperature reduction treatment by a cooling box, and is slowly cooled to below 60℃ at a cooling rate of 0.5℃ / min, and low-frequency vibration with a frequency of 20-40 Hz is applied at a critical temperature of 80℃; wherein the acceleration is 0.5g and the amplitude is 0.1mm.

[0072] It should be noted that in step S21, the carbon fiber is made into a prepreg with epoxy resin, which ensures the uniformity of the fiber and the resin and avoids uneven mixing during use. At the same time, controlling the weight content of the epoxy resin at 35±2% can ensure the stability of the performance of the composite material, and optimize the mechanical properties and curing characteristics of the material. The width of the layer tape is cut to 50-100 mm to meet the needs of winding and lamination, ensuring that the laying can be flexibly carried out in the subsequent step S22. In step S22, a seven-axis fiber winding machine is used for winding, which can accurately control the laying angle, and the laying angle gradually changes from ±45° to ±75°, so that the fiber direction of the carbon fiber under the action of bending or tensile force is highly optimized, improving the strength and stability of the composite material in multiple directions; Local pressure is applied in the microstructure area to achieve mechanical interlocking between the carbon fiber and the aluminum alloy inner layer, which helps to enhance the adhesion between the carbon fiber and the aluminum alloy inner layer, ensuring the stability and durability of the composite material during subsequent use.

[0073] In step S23, the intermediate layer of carbon fiber is subjected to gradient curing treatment, which can optimize the cross-linking degree of the resin and improve the mechanical properties of the material. By gradient curing, the temperature and pressure are gradually increased to ensure uniform stress distribution of the composite material during the curing process, effectively avoid stress concentration between the layers, reduce the risk of micro-cracks, and make the combination of carbon fiber and resin more closely, thereby improving the mechanical strength and durability of the final structure. In step S24, slow cooling to below 60°C at a cooling rate of 0.5°C / min helps to eliminate the internal stress generated during the curing process of the composite material, reduces the dimensional change caused by thermal stress, and ensures the stability of the structure. Low-frequency vibration (frequency 20-40 Hz) is applied during the cooling process, which can further promote the flow of uncured resin, help the material better integrate, and at the same time promote the interlayer bonding. In addition, low-frequency vibration can also help to reduce interlayer stress, enhance the toughness and crack resistance of the overall structure.

[0074] Specifically, step S23 includes:

[0075] Step S231, first stage curing, heating to 80-100°C at a heating rate of 1.5-2.5°C / min, and holding for 30-40 minutes, while applying a vacuum negative pressure environment with a vacuum degree ≤50Pa;

[0076] Step S232, second stage curing, heating to 120-150°C at a heating rate of 0.5-1.0°C / min, applying a uniform pressure of 0.6-0.8 MPa, and maintaining for 90-120 minutes;

[0077] Step S233, the third stage curing, the temperature is raised to 170-180℃ at a heating rate of 3-5℃ / min, the pressure is raised to 1.0-1.2MPa, and the constant temperature curing time is 30-50min.

[0078] It should be noted that in the first stage curing, the crosslinking reaction of the epoxy resin can be started to initiate curing; simultaneously, a negative pressure environment with a vacuum degree ≤50Pa is applied, which helps to remove bubbles in the resin and reduce internal stress generated during curing, thereby improving the compactness and overall quality of the material. The negative pressure can promote the resin to penetrate the carbon fibers, improving the interfacial adhesion strength. In the second stage curing, the equal pressure treatment helps to balance the internal and external pressure, further ensuring good combination of the resin and carbon fibers, preventing stress concentration during curing. Maintaining a curing time of 90-120min further promotes the crosslinking process of the epoxy resin, enhancing the mechanical properties of the material and ensuring that it reaches the designed strength. In the third stage curing, the high temperature and high pressure environment helps to further promote the crosslinking of the epoxy resin, forming a more robust polymer network structure. Setting a constant temperature curing time of 30-50min effectively improves the high temperature resistance and mechanical properties of the final composite material.

[0079] In an embodiment, step S3, a stainless steel woven mesh is pre-installed on the outer surface of the preliminary structure, and an engineering plastic outer layer is injection molded to obtain a composite motor housing; wherein the stainless steel woven mesh is embedded between the carbon fiber intermediate layer and the engineering plastic outer layer. In this embodiment, the stainless steel woven mesh embedded between the carbon fiber intermediate layer and the engineering plastic outer layer enhances the overall toughness and tensile strength of the housing, and suppresses high-frequency electromagnetic interference of the motor. The stainless steel woven mesh can disperse shear stress during the injection molding process, preventing the carbon fiber layer from cracking due to plastic shrinkage, and improving the interfacial bonding strength through the mechanical interlocking effect of the metal mesh and the plastic; the stainless steel woven mesh as an electromagnetic shielding layer enhances the motor's anti-interference ability.

[0080] Specifically, step S3 includes:

[0081] Step S31, providing a stainless steel woven mesh, and performing plasma cleaning on the stainless steel woven mesh by a plasma device; wherein the argon gas flow is 20-30L / min, the power is 300-500W, and the cleaning time is 5-8min; the stainless steel woven mesh is a structure known in the art and will not be described here.

[0082] Step S32, spin coating epoxy-silane coupling agent on the plasma cleaned stainless steel woven mesh by a spin coating device, and pre-curing at a temperature of 150-180℃ for 30min; wherein the thickness of the epoxy-silane coupling agent is 1-3μm; in this embodiment, the pre-curing treatment uses a curing oven commonly used in the art, which will not be described here.

[0083] Step S33, using a six-axis robot to fit the stainless steel woven mesh to the outer surface of the carbon fiber intermediate layer, and apply 0.1~0.3MPa negative pressure adsorption fixation;

[0084] Step S34, using gradient injection molding method, PA66-GF30 material is selected for injection molding of engineering plastic outer layer, glass fiber content is 30±2wt%; barrel temperature is set to 280~300℃, mold temperature is 80~100℃. PA66-GF30 material is commonly used in the art, and will not be described here.

[0085] It should be noted that in step S31, the stainless steel woven mesh is cleaned by plasma, which can effectively remove surface contaminants, grease and oxidation layer, making the surface cleaner and improving its adhesion, which helps the coating of epoxy-silane coupling agent in step S32. In step S32, the coating of epoxy-silane coupling agent provides good chemical bonding force for the stainless steel woven mesh, and reacts chemically with the stainless steel surface, enhancing the adhesion between the stainless steel woven mesh and the carbon fiber intermediate layer. In step S33, the cleaned stainless steel woven mesh is fitted by using a six-axis robot, ensuring accurate alignment and improving the consistency and reliability of the fitting. By applying 0.1~0.3MPa negative pressure adsorption fixation, the stainless steel woven mesh can be stably adhered to the outer surface of the carbon fiber intermediate layer, avoiding misalignment or displacement in the subsequent injection molding process, and facilitating the molding of the engineering plastic outer layer. In step S34, gradient injection molding method is used to optimize the flow and filling process of the material in the mold, improve the filling rate and molding quality of the mold. PA66-GF30 material (containing 30±2wt% glass fiber) is selected as the outer layer to ensure the strength, stiffness and durability of the outer layer material, which meets the needs of high-performance motors.

[0086] In step 34, the gradient injection molding pressure is specifically:

[0087] The first stage of the applied pressure is 80~100MPa, 2~3s to fill 90% of the cavity 90% volume, to achieve high-speed injection of plastic;

[0088] The second stage of the applied pressure is 40~60MPa, lasting 10~15s;

[0089] The third stage of the applied pressure is 20~30MPa, to eliminate the weld line.

[0090] It should be noted that, since the first stage pressure is set to 80~100MPa, high-speed injection can quickly fill the cavity with 90% of the plastic volume, which helps to reduce the weld line and bubble generation. Since the second stage pressure is set to 40~60MPa, it ensures the uniformity and integrity of the plastic, and maintains 10~15 seconds to ensure sufficient pouring. Since the third stage pressure is set to 20~30MPa, it eliminates the weld line, ensures the integrity and strength of the outer layer, and further improves the overall performance and appearance.

[0091] It should also be noted that the final temperature of the carbon fiber gradient curing in step S23 is 180℃, which is higher than the injection molding temperature of the engineering plastic (the melting temperature of PA66-GF30 is about 260℃), and the mold temperature during injection molding is only 80~100℃, which does not trigger the thermal degradation of the carbon fiber intermediate layer (epoxy resin TG>200℃), achieving thermal matching of carbon fiber curing and engineering plastic injection molding.

[0092] Working principle: the processing method of the composite motor shell provided by the application combines aluminum alloy, carbon fiber and engineering plastic, and the composite motor shell has high strength and rigidity. The added carbon fiber significantly improves the strength and impact resistance of the material. The insulation layer formed on the inner surface of the aluminum alloy inner layer can effectively isolate the current and prevent electrical short circuit and leakage, thereby enhancing the safety of the motor. The microstructure formed on the outer surface of the aluminum alloy inner layer can improve the adhesion of the material, increase the surface area, and improve the composite effect of the subsequent carbon fiber and engineering plastic outer layer. The cooling channel arranged in the aluminum alloy inner layer can effectively discharge the heat generated during the operation of the motor, thereby enhancing the heat dissipation effect. The stainless steel woven mesh embedded between the carbon fiber intermediate layer and the engineering plastic outer layer enhances the overall toughness and tensile strength of the shell and suppresses the high-frequency electromagnetic interference of the motor. Therefore, the application solves the technical problem of the lack of electromagnetic shielding function in the prior art composite motor shell.

[0093] Example two:

[0094] The composite motor shell provided by the embodiment of the application is prepared by the processing method of the composite motor shell of the first aspect, and includes an aluminum alloy inner layer, the aluminum alloy inner layer is combined with a carbon fiber intermediate layer, the outer surface of the carbon fiber intermediate layer is wrapped with an engineering plastic outer layer, and a stainless steel woven mesh is embedded between the carbon fiber intermediate layer and the engineering plastic outer layer.

[0095] The inner surface of the aluminum alloy inner layer is provided with an insulation layer, the outer surface of the aluminum alloy inner layer is provided with a microstructure, and the aluminum alloy inner layer has a cooling channel.

[0096] It should be noted that the combination of aluminum alloy and carbon fiber provides excellent strength-to-weight ratio, making the motor lightweight and powerful, suitable for modern electric and high-performance equipment. Through the cooling channel arrangement in the aluminum alloy inner layer, the motor can be efficiently cooled under high load, reducing the risk of overheating and improving the operation reliability and life of the motor. Through the combination between each layer, each part can play the maximum function, forming a high-performance composite. The composite motor shell not only has excellent structural strength, but also can ensure the stability and safety of the motor in various environments. The stainless steel woven mesh not only enhances the toughness and stability of the structure, but also effectively shields external electromagnetic interference due to its metal material and electrically conductive properties, reducing the impact of electromagnetic radiation on internal components and improving the electromagnetic compatibility of the motor. Carbon fiber can also provide electrical conductivity under certain conditions, and the combination with stainless steel mesh forms a good electromagnetic shielding layer, further improving the electromagnetic interference suppression effect of the entire motor shell. This multi-layer structure can effectively isolate electromagnetic waves and improve the stability and reliability of the motor. Through the combination of aluminum alloy inner layer, carbon fiber middle layer, engineering plastic outer layer and stainless steel woven mesh, an effective multi-protection system is formed, which can not only resist physical damage and chemical corrosion, but also shield electromagnetic interference from the external environment, ensuring the safe operation of the motor in complex environments. In high electromagnetic interference environments such as factories, medical, aerospace or military equipment, the improved composite motor shell can ensure the normal operation of the equipment, and has good market applicability.

[0097] The above-described and above-embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of machining a composite motor housing, characterized by, Comprise: Step S1, the inner layer of aluminum alloy is formed by vacuum high-pressure die casting, and the cooling runner of double helix is formed by integrating the cooling sand core during the die casting process; the inner surface of the aluminum alloy inner layer is subjected to micro-arc oxidation treatment to process an α-Al2O3 insulation layer; a honeycomb-shaped microstructure is processed on the outer surface of the aluminum alloy inner layer by a five-axis linkage micro-milling process; Step S2, the prepreg is made of carbon fiber and epoxy resin, the prepreg is wound on the aluminum alloy inner layer by a seven-axis fiber winding machine, and the microstructure area is locally pressurized to form a carbon fiber intermediate layer, and then a curing treatment is performed to obtain a preliminary structure; the preliminary structure comprises an aluminum alloy inner layer and a carbon fiber intermediate layer; Step S3, a stainless steel woven mesh is provided, the stainless steel woven mesh is subjected to plasma cleaning, then an epoxy-silane coupling agent is spin-coated and pre-cured; A mechanical hand is used to attach the treated stainless steel woven mesh to the outer surface of the carbon fiber intermediate layer; an engineering plastic outer layer is formed by gradient injection molding on the outer surface of the stainless steel woven mesh to obtain a composite motor shell; wherein the stainless steel woven mesh is embedded between the carbon fiber intermediate layer and the engineering plastic outer layer.

2. The method of machining a composite motor housing of claim 1, wherein, The step S1 comprises: Step S11, the inner layer of aluminum alloy is formed by vacuum high-pressure die casting, the injection speed is controlled at 5.8-6.5 m / s, the mold temperature is maintained at 240-280℃, and the cooling sand core is integrated during the die casting process to form a double-helix cooling runner; wherein the helix angle of the cooling runner is 30-40°, and the pitch is 100-150 mm; Step S12, the inner surface of the aluminum alloy inner layer is subjected to micro-arc oxidation treatment to form an α-Al2O3 insulation layer with a thickness of 50-60 μm; wherein the oxidation voltage is 550-650 V, the frequency is 800-1200 Hz, and the treatment time is 45-60 minutes; Step S13, the α-Al2O3 insulation layer is subjected to surface modification treatment; Step S14, a honeycomb-shaped microstructure is processed on the outer surface of the aluminum alloy inner layer by a five-axis linkage micro-milling process; wherein the unit side length of the microstructure is 1.0-1.5 mm, the depth is 0.4-0.7 mm, and the wall thickness is 0.15-0.25 mm.

3. The method of machining a composite motor housing of claim 2, wherein, The step S13 comprises: Step S131, after the micro-arc oxidation treatment, the inner surface of the aluminum alloy inner layer is spin-coated with a ZrO2 suspension, and is cured in a vacuum drying oven at a drying temperature of 120-150℃ for 1-2 hours to form a ZrO2 coating layer; wherein the spin-coating speed is 800-1200 rpm, and the coating thickness is 10-15 μm; Step S132, the ZrO2 coating layer is subjected to laser scanning by a fiber laser to form a metallurgical bond between the surface ZrO2 particles and the α-Al2O3 matrix, and the cladding depth is 3-5 μm; wherein the wavelength of the fiber laser is 1064 nm, the power is 200-300 W, and the spot diameter is 50 μm; In step S133, the ZrO2 coating layer after laser scanning is polished by a magneto-rheological finishing process to form a dense transition layer with a thickness of 2-5 μm; wherein the polishing process uses CeO2 abrasive with a particle size of 1-3 μm, and the polishing pressure is 0.05-0.1 MPa.

4. The method of machining a composite motor housing of claim 3, wherein, After the step S14, the step S1 further comprises: In step S15, the inner wall of the cooling flow channel is sandblasted, using Al2O3 abrasive with a particle size of 80-120 μm, and the sandblasting pressure is 0.4-0.6 MPa.

5. The method of machining a composite motor housing according to any one of claims 1 to 4, wherein The step S2 comprises: In step S21, a prepreg is made of carbon fiber and epoxy resin, and the prepreg is cut into a lay-up tape with a width of 50-100 mm; wherein the weight content of epoxy resin is 35±2%; In step S22, the lay-up tape is wound on the aluminum alloy inner layer by a seven-axis fiber winding machine, and local pressure is applied in the area of the microstructure to form a carbon fiber intermediate layer; wherein the main shaft rotation speed is 10-15 rpm, the fiber tension is 70-90 N, the winding angle gradually changes from ±45° to ±75° in the axial direction, the angle increment of each turn is 0.5°, and the pressure is 0.3-0.5 MPa; In step S23, the carbon fiber intermediate layer is subjected to gradient curing treatment to obtain a preliminary structure.

6. The method of machining a composite motor housing of claim 5, wherein, The step S23 comprises: In step S231, first-stage curing, the temperature is raised to 80-100 °C at a temperature raising rate of 1.5-2.5 °C / min, and the temperature is maintained for 30-40 minutes, and a vacuum negative pressure environment with a vacuum degree of ≤50 Pa is applied synchronously; In step S232, second-stage curing, the temperature is raised to 120-150 °C at a temperature raising rate of 0.5-1.0 °C / min, a uniform pressure of 0.6-0.8 MPa is applied, and the temperature is maintained for 90-120 minutes; In step S233, third-stage curing, the temperature is raised to 170-180 °C at a temperature raising rate of 3-5 °C / min, the pressure is raised to 1.0-1.2 MPa, and the temperature is maintained for 30-50 minutes.

7. The method of machining a composite motor housing of claim 5, wherein, After the step S23, it further comprises: In step S24, the preliminary structure after curing is subjected to cooling treatment, and the temperature is slowly cooled to below 60 °C at a cooling rate of 0.5 °C / min, and low-frequency vibration with a frequency of 20-40 Hz is applied at a critical temperature of 80 °C; wherein the acceleration is 0.5 g, and the amplitude is 0.1 mm.

8. The method of machining a composite motor housing according to any one of claims 1 to 4, wherein The step S3 comprises: In step S31, a stainless steel woven mesh is provided, and the stainless steel woven mesh is subjected to plasma cleaning; wherein the argon flow rate is 20-30 L / min, the power is 300-500 W, and the cleaning time is 5-8 minutes; In step S32, the stainless steel woven mesh after plasma cleaning is spin-coated with epoxy-silane coupling agent, and pre-cured at a temperature of 150-180 °C for 30 minutes; wherein the thickness of the epoxy-silane coupling agent is 1-3 μm; In step S33, the stainless steel woven mesh is attached to the outer surface of the carbon fiber intermediate layer using a six-axis robot, and a negative pressure of 0.1-0.3 MPa is applied for adsorption and fixation. Step S34, using gradient injection molding method, PA66-GF30 material injection molding engineering plastic outer layer, glass fiber content is 30±2wt%; barrel temperature is set to 280~300℃, mold temperature is 80~100℃.

9. The method of machining a composite motor housing of claim 8, wherein, In the step S34, the gradient injection molding pressure is specifically: The first stage of the applied pressure is set to 80~100MPa, 2~3s to fill 90% of the volume of the cavity 90% to achieve high-speed injection of plastic; The second stage of the applied pressure is set to 40~60MPa, lasting 10~15s; The third stage of the applied pressure is set to 20~30MPa to eliminate the weld line.

10. A composite motor case produced by the method of claim any one of claims 1 to 9, characterized by, The aluminum alloy inner layer is composed of an aluminum alloy inner layer, a carbon fiber intermediate layer, and an engineering plastic outer layer, and a stainless steel woven mesh is embedded between the carbon fiber intermediate layer and the engineering plastic outer layer. The inner surface of the aluminum alloy inner layer is provided with an insulating layer, the outer surface of the aluminum alloy inner layer is provided with a microstructure, and the aluminum alloy inner layer has a cooling channel.

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