Special oil for electric drive system and preparation method thereof
Through the combination of base oil, antioxidants, phosphorous acid and its derivatives and metal protecting agents of a specific proportion, the problem of insufficient thermal stability and electrical insulation of the special oil for the electric drive system at high temperatures is solved, and the efficient operation and long life of the electric drive system are achieved.
Patent Information
- Application Number
- CN202510492239.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2025-08-12
AI Technical Summary
The oil for existing electric drive systems is difficult to meet excellent thermal conductivity, thermal stability, electrical insulation and material compatibility at the same time when operating at high power density and high efficiency, resulting in limited stability and life of the electric drive system.
A specific proportion of base oil, antioxidants, phosphorous acid and its derivatives, metal protecting agents and deflators are used to form a synergistic effect to improve the comprehensive performance of the oil product.
On the basis of ensuring good low-temperature fluidity and high-temperature thermal stability, special oil for electric drive system has excellent electrical insulation and material compatibility, meeting the needs of cutting-edge electric drive systems, extending equipment life and improving operating efficiency.
Smart Images
Figure BDA0005365909060000051 
Figure BDA0005365909060000071 
Figure BDA0005365909060000081
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of special oils for electric drive systems, and in particular to a special oil for electric drive systems and a preparation method thereof. Background Art
[0002] At present, the special oil of the electric drive system is mainly responsible for the heat dissipation and lubrication of the stator, rotor, resolver, shaft gear, bearings and other components of the multi-motor combined box assembly. The special oil is exchanged and cooled externally through the external water channel of the oil cooler.
[0003] When the electric drive system operates at high power density and high efficiency, a large amount of heat is generated. This requires that the special oil needs to have excellent thermal conductivity and heat dissipation efficiency, and maintain good thermal stability at high temperatures to ensure the stable operation and long service life of the electric drive system; at the same time, the special oil for the electric drive system needs to have good electrical insulation properties, that is, it is not easy to produce electrochemical reactions under the action of the electric field to prevent electrical breakdown and short circuits, and protect the electronic components inside the electric drive system; the special oil also needs to have good compatibility with various materials in the electric drive system (such as metals, plastics, rubber seals, etc.) to avoid material corrosion or expansion.
[0004] In summary, with the development of electric drive systems, corresponding oil products need to strike a balance between multiple performances, such as high-temperature stability, electrical insulation, material compatibility, etc. The quality of oil used in existing electric drive systems needs to be further optimized and improved. Summary of the Invention
[0005] In order to solve the above technical problems, the present application provides a special oil for electric drive system and a preparation method thereof.
[0006] The present application provides a special oil for electric drive systems, specifically comprising the following components in parts by weight: 90-95 parts of base oil, 2.76-5.2 parts of antioxidant, 0.36-1.0 parts of phosphorous acid and its derivatives, 0.36-0.72 parts of metal protective agent, and 3-5 parts of pour point depressant; the antioxidant is composed of a mixture of nonyl-N-(nonylphenyl) aniline, a phenolic antioxidant, and a 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1.2-2.0:1.2-1.7:0.36-1.5; The metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.5-1.5:0.5-1.5.
[0007] The base oil in the technical solution provided in this application has good electrical insulation and thermal stability.
[0008] Among antioxidants, nonyl-N-(nonylphenyl)aniline effectively inhibits oxidation reactions in coolant compositions caused by high temperatures and oxidative environments during use, significantly extending the coolant's service life and protecting machinery from corrosion and wear caused by oxidation products. 2,6-Di-tert-Butylphenol, a highly effective antioxidant, inhibits oxidation reactions in lubricating oils under high temperatures and oxidative conditions, extending the lubricant's service life, reducing oil aging and deterioration, and thus protecting machinery from corrosion caused by oxidation products. It also exhibits certain anti-wear properties, reducing friction and wear between mechanical components, thereby improving the efficiency and lifespan of mechanical equipment. 2,2'-Iminobisethanol-N-tallow alkyl derivatives help disperse contaminants and wear-generated particles in the lubricant, preventing them from depositing inside the engine, maintaining engine cleanliness and improving efficiency. They also possess excellent antioxidant properties, slowing the lubricant's oxidation process and maintaining stable lubricant performance. These derivatives form a protective film on metal surfaces, reducing direct metal-to-metal contact, thereby reducing wear and extending the service life of mechanical components. The present application achieves a synergistic effect by precisely designing a mixture of nonyl-N-(nonylphenyl) aniline, a phenolic antioxidant, and a 2,2'-iminobisethanol-N-tallow alkyl derivative in the above-mentioned weight ratio to form an antioxidant, thereby greatly improving the overall performance of the oil used in the electric drive system.
[0009] Phosphorous acid and its derivatives have good antioxidant properties, which can delay the oxidation process of lubricating oil under high temperature and long-term use, maintain the stable performance of lubricating oil and extend its service life; phosphorous acid and its derivatives, such as phosphite esters, can improve the extreme pressure and anti-wear properties of lubricating oil. Under high temperature and high load conditions, phosphite esters can form stable friction films on metal surfaces, such as phosphate and polyphosphate films, effectively reducing direct contact between metals, reducing wear and protecting mechanical parts.
[0010] Among the metal protectors: 3-(isodecyloxy)-1-propylamine can form a stable protective film on the metal surface under high load and high temperature conditions, reducing direct contact between metals, thereby reducing wear and protecting mechanical parts; at the same time, 3-(isodecyloxy)-1-propylamine has antioxidant properties, which can delay the oxidation of lubricating oil during use, maintain the stability of lubricating oil performance, and extend its service life; it helps to disperse pollutants and particles generated by wear in the lubricating oil, keep the engine clean, and improve efficiency. 4 (or 5)-methyl 1H-benzotriazole is an effective metal passivator, which can form a stable protective layer with the metal surface to prevent metal oxidation and corrosion; this compound can form a tight adsorption film, which is particularly suitable for corrosion protection of copper and its alloys, preventing corrosive media from contacting the metal surface. This application precisely designs the above-mentioned weight ratio of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole to form a metal protector, so that the two components work synergistically, greatly improving the comprehensive performance of the oil used in the electric drive system.
[0011] The pour point depressant changes the shape, size and number of wax crystals through eutectic or adsorption, inhibiting the formation of crystal networks in lubricating oils and maintaining the fluidity of oils to meet the requirements of use under low temperature conditions.
[0012] Preferably, the electric drive system special oil specifically includes the following components in parts by weight: 91-94 parts of base oil, 3.4-4.6 parts of antioxidant, 0.6-0.8 parts of phosphorous acid and its derivatives, 0.46-0.62 parts of metal protective agent, and 3.5-4.5 parts of pour point depressant.
[0013] Preferably, the antioxidant is composed of a mixture of nonyl-N-(nonylphenyl)aniline, a phenolic antioxidant, and a 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1.5-2.0:1.2-1.5:0.9-1.2.
[0014] In a specific embodiment, the weight ratio of the nonyl-N-(nonylphenyl)aniline, phenolic antioxidant, and 2,2'-iminobisethanol-N-tallow alkyl derivative can be 1.2:1.2:0.36, 2.0:1.2:0.36, 1.2:1.7:0.36, 1.5:1.2:0.9, 2.0:1.2:0.9, 1.2:1.5:0.9, 2.0:1.5:0.9, 2.0:1.7:0.9, 1.5:1.2:1.2, 2.0:1.5:1.2, 1.5:1.7:1.2, and 2.0:1.7:1.2.
[0015] Through experimental analysis, it can be seen that the present application can further improve the comprehensive performance of the special oil for electric drive system by controlling the antioxidant composed of nonyl-N-(nonylphenyl) aniline, phenolic antioxidant, and 2,2'-iminobisethanol-N-tallow alkyl derivative in the above-mentioned weight ratio.
[0016] Preferably, among the antioxidants, the phenolic antioxidant is selected from one or more of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, and 2,2'-methylenebis(4-methyl-6-tert-butylphenol).
[0017] Preferably, the metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.7-1.2:0.7-1.2.
[0018] In a specific embodiment, the weight ratio of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole can be 1:1, 0.5:1, 0.5:1.5, 1.5:1, 1.5:0.5, 0.7:1.2, 1.2:0.7, 0.7:1, 1:0.7, 1.2:1, 1:1.2.
[0019] Through experimental analysis, it can be seen that the present application can further improve the comprehensive performance of the special oil for electric drive system by controlling the metal protective agent composed of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in the above-mentioned weight ratio.
[0020] Preferably, the pour point depressant is selected from one or more of VISCOPLEX 7-200 pour point depressant and VISCOPLEX 1-300 pour point depressant.
[0021] Preferably, the pour point depressant is composed of a mixture of VISCOPLEX 7-200 pour point depressant and a terpolymer in a weight ratio of 1-4:6-9; the preparation method of the terpolymer is: acrylic acid, methyl methacrylate and polyoxyethyl glycerol ether are uniformly mixed, and then triphenylphosphine is added, and the mixture is reacted at a constant temperature of 100-120° C. for 3-5 hours under closed conditions, and then placed in a nitrogen atmosphere and irradiated using cobalt 60-γ radiation method for 60-80 minutes.
[0022] In a specific embodiment, the weight ratio of the VISCOPLEX 7-200 pour point depressant to the terpolymer may be 1:6, 1:7, 1:9, 3:6, 3:7, 3:9, 4:6, 4:7, 4:9.
[0023] Preferably, in the preparation method of the terpolymer, the weight ratio of acrylic acid, methyl methacrylate, polyoxyethyl glycerol ether, and triphenylphosphine is 50-60:30-40:5-10:1-3.
[0024] In a specific embodiment, in the preparation method of the terpolymer, the weight ratio of acrylic acid, methyl methacrylate, polyoxyethylene glycerol ether, and triphenylphosphine can be 55:35:7:2.
[0025] Through experimental analysis, it can be seen that the present application controls the preparation of a ternary copolymer composed of acrylic acid, methyl methacrylate, polyoxyethyl glycerol ether, and triphenylphosphine in the above-mentioned weight ratio, and adopts a pour point depressant composed of a mixture of VISCOPLEX 7-200 pour point depressant and the ternary copolymer in a weight ratio of 1-4:6-9. This can further improve the comprehensive performance of the special oil for the electric drive system.
[0026] Preferably, the base oil is a C20-C50 synthetic alkane base oil selected from one or more of SK 100N, S-oil 100N, Abu Dhabi 8cst, Bahrain 8cst, and GTL250N.
[0027] In the second aspect, the present application provides a method for preparing the above-mentioned special oil for electric drive system, which specifically includes the following steps: weighing the corresponding weight of each raw material component respectively, mixing the antioxidant, phosphorous acid and its derivatives, and metal protective agent evenly to obtain a premix; then adding the premix and pour point depressant to the base oil and mixing evenly to obtain the special oil for electric drive system.
[0028] In summary, the technical solution of this application has the following effects: The electric drive system oil provided by this application, by screening the types of antioxidants and metal protectants, while accurately matching the amount of each raw material component of the design base oil, antioxidant, phosphorous acid and its derivatives, metal protectant, and pour point depressant, while ensuring good low-temperature fluidity, high-temperature thermal stability, oxidation resistance, and thermal conductivity, also has excellent electrical insulation and material compatibility, which can match the current cutting-edge electric drive system oil requirements. At the same time, this application further improves the comprehensive performance of the electric drive system oil by screening the type of pour point depressant. DETAILED DESCRIPTION
[0029] The present application is further described in detail below in conjunction with examples, comparative examples and performance testing experiments. These examples should not be construed as limiting the scope of protection claimed in this application.
[0030] The reagents of the present application are: nonyl-N-(nonylphenyl)aniline (CAS No.: 36878-20-3); 2,2'-iminobisethanol-N-tallow alkyl derivative (CAS No.: 61791-44-4; 3-(isodecyloxy)-1-propylamine (CAS No.: 30113-45-2); 4 (or 5)-methyl 1H-benzotriazole (CAS No.: 29385-43-1). The remaining raw materials are conventional reagents and can be obtained through ordinary commercial purchase. Example
[0031] Examples 1-3 Examples 1-3 respectively provide a special oil for an electric drive system and a preparation method thereof.
[0032] The difference between the above embodiments is that the amount of each component in the electric drive system special oil is different, as shown in Table 1.
[0033] The preparation method of the special oil for the electric drive system in the above embodiment is as follows: According to Table 1, the corresponding weights of the raw material components were weighed respectively, and an antioxidant (composed of a mixture of nonyl-N-(nonylphenyl)aniline, 2,6-di-tert-butylphenol, and 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1.5:1.2:0.9, i.e., a weight ratio of 5:4:3), a phosphite, and a metal protective agent (composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 1:1) were mixed uniformly to obtain a premix. Then, the premix and a pour point depressant (composed of a mixture of VISCOPLEX 7-200 pour point depressant and a terpolymer in a weight ratio of 3:7) were added to the base oil SK 100N and mixed uniformly to obtain the special oil for the electric drive system.
[0034] Among them, the preparation method of the ternary copolymer in the pour point depressant is: add acrylic acid, methyl methacrylate and polyoxyethyl glycerol ether into a reaction bottle, mix evenly, then add triphenyl phosphine, react at a constant temperature of 110°C for 4 hours under closed conditions, and then place it in a nitrogen atmosphere and irradiate it using cobalt 60-γ radiation method for 70 minutes to obtain the product; the weight ratio of acrylic acid, methyl methacrylate, polyoxyethyl glycerol ether and triphenyl phosphine is 55g:35g:7g:2g.
[0035] Table 1 Amount of modified filler in the electric drive system oil in Examples 1-3 and Comparative Example 1 Examples 4-7 Examples 4-7 respectively provide a special oil for an electric drive system and a preparation method thereof.
[0036] The difference between the above embodiment and embodiment 1 is that the composition of the antioxidant is different, as shown below.
[0037] In Example 4, the antioxidant is composed of a mixture of nonyl-N-(nonylphenyl)aniline, 2,6-di-tert-butylphenol, and 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1.2:1.7:0.36.
[0038] In Example 5, the antioxidant is composed of a mixture of nonyl-N-(nonylphenyl)aniline, 2,6-di-tert-butylphenol, and 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 2.0:1.2:1.5.
[0039] In Example 6, the antioxidant is composed of a mixture of nonyl-N-(nonylphenyl)aniline, 2,6-di-tert-butylphenol, and 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 2.0:1.5:1.2.
[0040] In Example 7, the antioxidant is composed of a mixture of nonyl-N-(nonylphenyl)aniline, 2,6-di-tert-butyl-p-cresol, and 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1.5:1.2:0.9.
[0041] The other process parameters in the above embodiment are the same as those in Example 1.
[0042] Examples 8-11 Examples 8-11 respectively provide a special oil for an electric drive system and a preparation method thereof.
[0043] The difference between the above embodiment and embodiment 1 is that the composition of the metal protective agent is different, as shown below.
[0044] In Example 8, the metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.5:1.5.
[0045] In Example 9, the metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 1.5:0.5.
[0046] In Example 10, the metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.7:1.2.
[0047] In Example 11, the metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 1.2:0.7.
[0048] The other process parameters in the above embodiment are the same as those in Example 1.
[0049] Examples 12-17 Examples 12-17 respectively provide a special oil for an electric drive system and a preparation method thereof.
[0050] The difference between the above embodiment and embodiment 1 is that the composition of the pour point depressant is different, as shown below.
[0051] In Example 12, the pour point depressant is composed of a mixture of VISCOPLEX 1-300 pour point depressant and a terpolymer in a weight ratio of 3:7.
[0052] In Example 13, the pour point depressant is composed of a mixture of VISCOPLEX 7-200 pour point depressant and a terpolymer in a weight ratio of 7:3.
[0053] In Example 14, the pour point depressant is composed of a mixture of VISCOPLEX 7-200 pour point depressant and a terpolymer in a weight ratio of 1:9.
[0054] In Example 15, the pour point depressant is composed of a mixture of VISCOPLEX 7-200 pour point depressant and a terpolymer in a weight ratio of 4:6.
[0055] In Example 16, in the preparation method of the terpolymer in the pour point depressant, an equal amount of polyoxypropylene polyethylene glycerol ether was used instead of polyoxyethyl glycerol ether.
[0056] In Example 17, in the preparation method of the ternary copolymer in the pour point depressant, the weight ratio of acrylic acid, methyl methacrylate, polyoxyethylene glycerol ether, and triphenylphosphine is 35g:55g:3g:4g.
[0057] The other process parameters in the above embodiment are the same as those in Example 1.
[0058] Comparative Example Comparative Example 1 This comparative example provides a special oil for an electric drive system and a preparation method thereof.
[0059] The difference between this comparative example and Example 1 is that the amounts of the components in the electric drive system special oil are different, as shown in Table 1.
[0060] The other process parameters in this comparative example are the same as those in Example 1.
[0061] Comparative Examples 2-5 Comparative Examples 2-5 respectively provide a special oil for an electric drive system and a preparation method thereof.
[0062] The difference between the comparative example and Example 1 is that the composition of the antioxidant or metal protective agent is different, as shown below.
[0063] In Comparative Example 2, the antioxidant is composed of a mixture of nonyl-N-(nonylphenyl)aniline and 2,6-di-tert-butylphenol in a weight ratio of 1.5:1.2.
[0064] In Comparative Example 3, the antioxidant is composed of a mixture of nonyl-N-(nonylphenyl)aniline, 2,6-di-tert-butylphenol, and 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1:2.5:0.1.
[0065] In Comparative Example 4, the metal protective agent is 3-(isodecyloxy)-1-propylamine.
[0066] In Comparative Example 5, the metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.2:2.
[0067] The other process parameters in the above comparative example are the same as those in Example 1.
[0068] Performance testing (1) Conventional physical and chemical performance The conventional physical and chemical performance test methods and performance test results of the special oils in Examples 1-17 are shown in Table 2.
[0069] Table 2 Conventional physical and chemical index performance test methods and performance test results of special oils in Examples 1-17 As can be seen from Table 2, the conventional physical and chemical performance indicators of the special oils prepared in Examples 1-17 meet the performance requirements for special oils in this field.
[0070] (1) Low-temperature fluidity, thermal stability, antioxidant performance, thermal conductivity, electrical insulation performance, and compatibility performance The low-temperature fluidity, thermal stability, antioxidant performance, thermal conductivity, electrical insulation performance, and compatibility performance testing methods of the special oils in Examples 1-17 and Comparative Examples 1-5 are shown in Table 3.
[0071] The test results of low-temperature fluidity, thermal stability, antioxidant performance, and thermal conductivity of the special oils in Examples 1-17 and Comparative Examples 1-5 are shown in Table 4; the test results of electrical insulation performance and compatibility of the special oils in Examples 1-18 and Comparative Examples 1-5 are shown in Table 5.
[0072] Table 3 Performance test methods for special oils: low-temperature fluidity, thermal stability, antioxidant properties, thermal conductivity, electrical insulation properties, and compatibility Table 4 Test results of low temperature fluidity, thermal stability, antioxidant performance and thermal conductivity of special oil Table 5 Test results of electrical insulation performance and compatibility of special oils Combined with the test results in the above table, it can be seen that the electric drive system oil provided by the technical solution of this application uses a synthetic oil with good electrical insulation and thermal stability as the base oil, combined with various functional additives, and optimizes the specific type and dosage relationship of each functional additive, effectively improving the overall quality of the oil. The electric drive system oil product prepared by this application, while ensuring good low-temperature fluidity and high-temperature thermal stability, also has excellent thermal conductivity, electrical insulation, material compatibility, etc., which can meet the current cutting-edge electric drive system oil requirements.
[0073] By comparing the test results of Examples 1-3 with those of Comparative Example 1, it can be seen that the amount of each raw material component has a great influence on the performance of the oil used in the electric drive system. The present application effectively improves the comprehensive performance of the oil used in the electric drive system by matching the amount of each raw material component.
[0074] By comparing the test results of Examples 1, 4-7 with Comparative Examples 2-3, it can be seen that the antioxidant in Comparative Example 2 is composed of a mixture of nonyl-N-(nonylphenyl) aniline and 2,6-di-tert-butylphenol in a weight ratio of 1.5:1.2, and the antioxidant in Comparative Example 3 is composed of a mixture of nonyl-N-(nonylphenyl) aniline, 2,6-di-tert-butylphenol and 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1:2.5:0.1. The performance of the prepared electric drive system oil is poor; while the present application selects an antioxidant composed of a mixture of nonyl-N-(nonylphenyl) aniline, a phenolic antioxidant and 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1.2-2.0:1.2-1.7:0.36-1.5, which effectively improves the comprehensive performance of the electric drive system oil.
[0075] By comparing the test results of Examples 1, 8-11 with Comparative Examples 4-5, it can be seen that the metal protective agent in Comparative Example 4 is 3-(isodecyloxy)-1-propylamine, and the metal protective agent in Comparative Example 5 is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.2:2. The performance of the prepared electric drive system oil is poor; while the present application selects a metal protective agent composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.5-1.5:0.5-1.5, which effectively improves the comprehensive performance of the electric drive system oil.
[0076] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.
Claims
1. A special oil for electric drive system, characterized in that: Specifically, it includes the following components in parts by weight: 90-95 parts of base oil, 2.76-5.2 parts of antioxidant, 0.36-1.0 parts of phosphorous acid and its derivatives, 0.36-0.72 parts of metal protective agent, and 3-5 parts of pour point depressant; The antioxidant is composed of a mixture of nonyl-N-(nonylphenyl) aniline, a phenolic antioxidant, and a 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1.2-2.0:1.2-1.7:0.36-1.5; The metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.5-1.5:0.5-1.
5.
2. The electric drive system oil according to claim 1, characterized in that: Specifically, the invention comprises the following components in parts by weight: 91-94 parts of base oil, 3.4-4.6 parts of antioxidant, 0.6-0.8 parts of phosphorous acid and its derivatives, 0.46-0.62 parts of metal protective agent, and 3.5-4.5 parts of pour point depressant.
3. The electric drive system oil according to claim 1, characterized in that: The antioxidant is composed of a mixture of nonyl-N-(nonylphenyl) aniline, a phenolic antioxidant and a 2,2'-iminobisethanol-N-tallow alkyl derivative in a weight ratio of 1.5-2.0:1.2-1.5:0.9-1.
2.
4. The electric drive system oil according to claim 1, characterized in that: Among the antioxidants, the phenolic antioxidant is selected from one or more of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, and 2,2'-methylenebis(4-methyl-6-tert-butylphenol).
5. The electric drive system oil according to claim 1, characterized in that: The metal protective agent is composed of a mixture of 3-(isodecyloxy)-1-propylamine and 4 (or 5)-methyl 1H-benzotriazole in a weight ratio of 0.7-1.2:0.7-1.
2.
6. The electric drive system oil according to claim 1, characterized in that: The pour point depressant is selected from one or more of VISCOPLEX 7-200 pour point depressant and VISCOPLEX 1-300 pour point depressant.
7. The electric drive system oil according to claim 1, characterized in that: The pour point depressant is composed of a mixture of VISCOPLEX 7-200 pour point depressant and a terpolymer in a weight ratio of 1-4:6-9. The preparation method of the terpolymer is as follows: acrylic acid, methyl methacrylate and polyoxyethyl glycerol ether are uniformly mixed, and then triphenylphosphine is added. The mixture is reacted at a constant temperature of 100-120° C. for 3-5 hours under closed conditions, and then placed in a nitrogen atmosphere and irradiated using a cobalt 60-γ radiation method for 60-80 minutes to obtain the terpolymer.
8. The electric drive system oil according to claim 7, characterized in that: In the preparation method of the terpolymer, the weight ratio of acrylic acid, methyl methacrylate, polyoxyethyl glycerol ether and triphenylphosphine is 50-60:30-40:5-10:1-3.
9. The electric drive system oil according to claim 1, characterized in that: The base oil is a C20-C50 synthetic alkane base oil, and the base oil is selected from one or more of SK 100N, S-oil 100N, Abu Dhabi 8cst, Bahrain 8cst, and GTL250N.
10. A method for preparing the special oil for electric drive system according to any one of claims 1 to 9, characterized in that: The specific steps include: Respectively weigh the corresponding weights of the raw material components, and mix the antioxidant, phosphorous acid and its derivatives, and the metal protective agent evenly to obtain a premix; then add the premix and pour point depressant to the base oil and mix evenly to obtain the special oil for the electric drive system.