Lubricating oil composition for new energy electric vehicle transmission system and preparation method thereof

Abstract

The application discloses a lubricating oil composition for a new energy electric vehicle transmission system, which comprises the following components in percentage by mass: an anti-wear agent 0.01-2%; an anti-rust agent 0.01-2%; a metal deactivator 0.01-1%; a pour point depressant 0-3%; and the balance is base oil, and the sum of the percentage by mass of the above components is 100%. The application further discloses a preparation method of the lubricating oil composition, specifically: the anti-wear agent, the anti-rust agent, the metal deactivator and the pour point depressant are added into the base oil, and the components are uniformly dissolved in the base oil by blending, and the lubricating oil composition is obtained. The side chain of the BTTP is extended, three siloxane structures are introduced, so that the lubricating oil composition can have excellent solubility in fluorosilicone oil and better wear resistance. In addition, the lubricating oil composition adopting the fluorosilicone oil base oil formula has good low-temperature fluidity, oxidation resistance and electrochemical performance, and can meet the lubrication and cooling requirements of the oil-cooled motor reduction gearbox transmission system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lubricating oil, and particularly relates to a lubricating oil composition for a new energy electric vehicle transmission system, and a preparation method of the lubricating oil composition. BACKGROUND

[0002] New energy vehicle transmission systems are divided into water-cooled motor reduction gearbox systems and oil-cooled motor reduction gearbox systems according to the cooling method. Compared with water-cooled motors, oil-cooled motors can directly cool the winding end portion with the highest temperature, especially the flat wire winding with a larger exposed area, and can actively cool the internal rotor components. At the same time, the oil-cooled motor reduction gearbox transmission system is conducive to the integration of the motor and the gearbox, and is also conducive to the integration of the motor and the vehicle thermal management system. When the ambient temperature is low, heating oil improves the lubrication and stirring efficiency, and heating battery components improves the heat utilization efficiency. Therefore, oil-cooled motors have the advantage of miniaturization development compared with water-cooled motors and have a very broad technical prospect. However, this also means that the lubricating oil composition for the oil-cooled motor reduction gearbox transmission system needs to have excellent low-temperature performance and oxidation resistance, as well as good specific heat capacity, thermal conductivity and electrochemical performance to meet the needs of the oil-cooled motor reduction gearbox transmission system.

[0003] Chinese patent (application number: 201910813451.X, publication number: CN 112442412 A) discloses a lubricating oil composition for a hybrid vehicle gearbox, which comprises at least one viscosity index improver, at least one dispersant, at least one antioxidant, a metal deactivator, an ester oil and a mineral base oil. The composition provided by the invention can meet the lubrication requirements of gears and bearings in the hybrid vehicle gearbox, and therefore can be used for the lubricating oil of the hybrid vehicle gearbox. The obtained lubricating oil has excellent low-temperature performance, extreme pressure and wear resistance, oxidation resistance, rust and corrosion resistance. Compared with ordinary gear oil products, the lubricating oil composition has excellent electrochemical performance in addition to excellent wear resistance and oxidation resistance, and is more suitable for the hybrid vehicle gearbox. Moreover, the composition is simple and the manufacturing process is simple.

[0004] A Chinese patent application (application number: 201711038962.6, publication number: CN107828481B) discloses a lubricant composition for electric vehicle transmissions and its preparation method. The composition comprises the following components by weight: 79.8-84.5% base oil, 4-7% polymethacrylate viscosity modifier, 10-13% gearbox oil compound, and 0.3-0.5% pour point depressant. The polymethacrylate viscosity modifier is a comb-like polymer, and the viscosity modifier has a shear stability index of no greater than 28. The advantages of this invention are that the resulting oil maintains viscosity under long-term, high-speed shear forces, providing reliable protection for electric vehicle transmissions. It has excellent shear stability, outstanding low-temperature rheology, and significantly improves the oil's high-temperature thickening ability at lower dosages. It also exhibits good dispersibility, reducing the deposition of oil oxides. When used in conjunction with the gearbox compound, it improves the oil's cleaning and dispersibility.

[0005] A Chinese patent (application number: 201510580512.4, publication number: CN105132107A) discloses a lubricating oil composition for pure electric vehicle transmissions. The composition uses functional additives such as a viscosity index improver, an extreme pressure anti-wear agent, an antioxidant, a sealing material swelling agent, a pour point depressant, an ashless dispersant, a rust inhibitor, and a metal passivator. The base oil uses one or more of PAO4, PAO10, and Class III hydrogenated base oils. The oil can meet the lubrication requirements of gears and bearings in pure electric vehicle transmissions, has excellent low-temperature performance, extreme pressure anti-wear properties, antioxidant properties, rust and corrosion resistance, simple ingredients, and a simple preparation process.

[0006] A Chinese patent (application number: 201680018979.2, publication number: CN 107429186 B) discloses a lubricant oil composition for electric vehicles or hybrid vehicles, which provides a lubricant oil composition for electric vehicles or hybrid vehicles with excellent gear characteristics, clutch characteristics, cooling properties and electrical insulation properties. The lubricant oil composition for electric vehicles or hybrid vehicles is formulated with (A) a base oil, and (B-1) a polyamide and / or (B-2) a polyol ester. As the aforementioned (A) base oil, the lubricant oil composition includes (A-1) a polyamide having a kinematic viscosity of 1.0 to 10.0 mm at 100°C. 2 / s of synthetic oil.

[0007] None of the aforementioned invention patents involve the use of fluorinated silicone base oils in lubricating oil compositions for oil-cooled motor reducer transmission systems, nor are there any related reports. Silicone oil has excellent low-temperature flow properties and high-temperature thermal oxidative stability. Introducing fluorocarbon groups into silicone oil not only maintains these excellent properties but also enhances its lubricity. Summary of the Invention

[0008] The present invention aims to provide a lubricating oil composition for a new energy electric vehicle transmission system, wherein the lubricating oil composition has good low-temperature fluidity, antioxidant properties and electrochemical properties.

[0009] Another object of the present invention is to provide a method for preparing a lubricating oil composition for a new energy electric vehicle transmission system.

[0010] The technical solution adopted by the present invention is that the lubricating oil composition for the transmission system of new energy electric vehicles includes the following components in percentage by mass: 0.01-2% anti-wear agent; 0.01-2% rust inhibitor; 0.01-1% metal deactivator; 0-3% pour point depressant; the balance is base oil, and the sum of the percentages by mass of the above components is 100%.

[0011] The present invention is also characterized in that:

[0012] The anti-wear agent is modified butyl triphenyl thiophosphate.

[0013] The preparation method of modified butyl triphenyl thiophosphate is as follows:

[0014] Mix hexamethylcyclotrisiloxane and BTTP in a molar ratio of 3:1, heat in an oil bath to 50-85°C and react at this temperature for 1-4 hours, then heat to 90-100°C and react for 2-5 hours. After cooling to room temperature, an oily transparent product is obtained, which is modified butyl triphenyl thiophosphate.

[0015] The rust inhibitor is dodecenylsuccinate half ester.

[0016] The metal deactivator is a liquid methylbenzotriazole derivative.

[0017] The base oil is any one of fluorosilicone oil, mineral base oil, coal-to-liquid base oil, poly-α-olefin synthetic oil, and ester synthetic oil.

[0018] Another technical solution adopted by the present invention is a method for preparing a lubricating oil composition for a new energy electric vehicle transmission system, specifically comprising:

[0019] Add anti-wear agent, rust inhibitor, metal deactivator and pour point depressant to the base oil and mix at 60-90℃ for 2-5h until the components are evenly dissolved in the base oil.

[0020] The beneficial effects of the present invention are as follows: the lubricating oil composition formulated with fluorosilicone oil base oil has good low-temperature fluidity, antioxidant properties and electrochemical properties, and can meet the lubrication and cooling requirements of the oil-cooled motor reducer transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of butyl triphenyl phosphorothioate;

[0022] Figure 2 It is a schematic diagram of the monomer molecular structure of fluorinated silicone oil;

[0023] Figure 3 It is a schematic diagram of the molecular structure of fluorinated silicone oil;

[0024] Figure 4 This is the reaction equation diagram of hexamethylcyclotrisiloxane and BTTP. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below with reference to specific embodiments and the accompanying drawings.

[0026] The lubricating oil composition for a new energy electric vehicle transmission system of the present invention comprises the following components in percentage by mass: 0.01-2% of an antiwear agent; 0.01-2% of a rust inhibitor; 0.01-1% of a metal deactivator; 0-3% of a pour point depressant; the balance being base oil, the sum of the percentages by mass of the above components being 100%;

[0027] The antiwear agent is modified butyl triphenyl thiophosphate (BTTP-Si-O);

[0028] The rust inhibitor is dodecenylsuccinate half ester;

[0029] The metal deactivator is a liquid methylbenzotriazole derivative;

[0030] The pour point depressant is polymethacrylate;

[0031] The base oil is any one of fluorosilicone oil, mineral base oil, coal-to-liquid base oil, poly-α-olefin (PAO) synthetic oil, and ester synthetic oil;

[0032] The excellent anti-wear performance of butyl triphenyl thiophosphate (BTTP) in lubricating oil is due to the formation of phosphorus-iron friction film and sulfur-iron friction film on the friction surface. Figure 1 As shown, BTTP is poorly soluble in silicone oil. It can be dissolved in ester oil first, and then the mixture of ester oil and BTTP is dissolved in silicone oil. However, the mixture solution of the two is not stable enough. In order to increase the solubility, the present invention retains the PO and P=S anti-wear components, and at the same time expands the side chain of BTTP and introduces Si-O groups to increase the solubility in fluorosilicone oil.

[0033] The molecular backbone of fluorosilicone oil is similar to that of silicone oil, both consisting of Si-O-Si bonds. Figure 2 and Figure 3 As shown, it has good thermal oxidation stability.

[0034] The anti-wear agent BTTP-Si-O of the present invention expands the side chain of BTTP and introduces three siloxane structures, so that it has excellent solubility in fluorine-containing silicone oil. At the same time, its own P=S, PO and other groups remain unchanged, thereby maintaining its good anti-wear performance.

[0035] The preparation method of modified butyl triphenyl thiophosphate (BTTP-Si-O) is as follows:

[0036] Mix hexamethylcyclotrisiloxane and BTTP in a molar ratio of 3:1, heat in an oil bath to 50-85°C and react at this temperature for 1-4 hours, then heat to 90-100°C and react for 2-5 hours. After cooling to room temperature, an oily transparent product is obtained, namely BTTP-Si-O. The reaction equation is as follows: Figure 4 As shown;

[0037] The method for preparing a lubricating oil composition for a new energy electric vehicle transmission system of the present invention comprises the following steps: adding an antiwear agent, a rust inhibitor, a metal deactivator, and a pour point depressant to a base oil, and blending the mixture at a temperature of 60-90° C. for 2-5 hours until the components are uniformly dissolved in the base oil;

[0038] Example 1

[0039] The composition of the lubricating oil composition of this embodiment is shown in Table 1:

[0040] Table 1 Composition of lubricating oil composition

[0041] name Dosage Antiwear agent BTTP-Si-O 0.15％ Dodecenylsuccinate half ester 0.1％ Liquid methylbenzotriazole derivatives 0.05％ Fluorosilicone oil 99.70％

[0042] Example 2

[0043] The composition of the lubricating oil composition of this embodiment is shown in Table 2:

[0044] Table 2 Composition of lubricating oil composition

[0045] name Dosage Antiwear agent BTTP-Si-O 0.15％ Dodecenylsuccinate half ester 0.1％ Liquid methylbenzotriazole derivatives 0.05％ Polymethacrylate 0.03％ Group II / III mineral base oils 99.67％

[0046] Example 3

[0047] The composition of the lubricating oil composition of this embodiment is shown in Table 3:

[0048] Table 3 Composition of lubricating oil composition

[0049] name Dosage Antiwear agent BTTP-Si-O 0.15％ Dodecenylsuccinate half ester 0.1％ Liquid methylbenzotriazole derivatives 0.05％ Polymethacrylate 0.03％ Coal-to-liquid base oil 99.67％

[0050] Example 4

[0051] The composition of the lubricating oil composition of this embodiment is shown in Table 4:

[0052] Table 4 Composition of lubricating oil composition

[0053]

[0054]

[0055] Example 5

[0056] The composition of the lubricating oil composition of this embodiment is shown in Table 5:

[0057] Table 5 Composition of lubricating oil composition

[0058] name Dosage Antiwear agent BTTP-Si-O 0.15％ Dodecenylsuccinate half ester 0.1％ Liquid methylbenzotriazole derivatives 0.05％ Adipate base oil 99.70％

[0059] The test results of the oil products prepared in Examples 1-5 are shown in Table 6:

[0060] Table 6 Oil test results

[0061]

[0062]

[0063] As can be seen from Table 6, the oil product blended using the fluorinated silicone oil base oil formula of Example 1 has excellent viscosity index, low-temperature flow properties and high-temperature oxidation resistance, good cooling performance and electrochemical properties, which are far superior to competing products developed using other types of base oils, and can effectively improve the working efficiency and service life of the oil-cooled motor reducer system.

[0064] The lubricating oil composition of the present invention has the following advantages: the unmodified antiwear agent is insoluble in the silicone base oil, while the modified antiwear agent BTTP-Si-O is highly soluble in the silicone base oil. The addition of BTTP-Si-O to the fluorinated silicone oil formulation provides excellent antiwear properties.

[0065] The performance comparison of the oil product of Example 1 of the present invention and commercially available competing products is shown in Table 7:

[0066] Table 7 Performance comparison of the oil of Example 1 and commercially available competing products

[0067]

[0068]

[0069] As can be seen from Table 7, the volume resistivity of the fluorinated silicone oil base oil formula of Example 1 is significantly higher than that of the competing products, and the electrochemical insulation performance is excellent; Example 1 has an extremely high viscosity index and its low-temperature flow performance (low-temperature viscosity) and high-temperature antioxidant stability (100°C viscosity reduction rate) are also better than those of the competing products; the failure level of the FZG gear abrasion test of Example 1 is level 6, achieving anti-wear performance comparable to that of the competing products.

[0070] In summary, in Example 1 of the present invention, fluorinated silicone oil is used as the base oil, and a modified anti-wear agent BTTP-Si-O soluble in fluorinated silicone oil is added to prepare a lubricating oil composition for an oil-cooled motor reducer transmission system. The composition has very excellent low-temperature fluidity, high-temperature antioxidant properties, and electrochemical insulation properties. The low-temperature performance and life far exceed those of competing products on the market, and the anti-wear performance is comparable to that of competing products on the market. The lubricating oil composition can meet the lubrication requirements of the oil-cooled motor reducer system.

Claims

1. A lubricating oil composition for a new energy electric vehicle transmission system, characterized in that: The following components are included in percentage by mass: anti-wear agent 0.01-2%; rust inhibitor 0.01-2%; metal deactivator 0.01-1%; pour point depressant 0-3%; the balance is base oil, and the sum of the percentages by mass of the above components is 100%; The base oil is fluorosilicone oil; the anti-wear agent is modified butyl triphenyl thiophosphate; the preparation method of the modified butyl triphenyl thiophosphate is: Mix hexamethylcyclotrisiloxane and BTTP in a molar ratio of 3:1, heat in an oil bath to 50-85°C and react at this temperature for 1-4 hours, then heat to 90-100°C and react for 2-5 hours. After cooling to room temperature, an oily transparent product is obtained, which is modified butyl triphenyl thiophosphate.

2. The lubricating oil composition for a new energy electric vehicle transmission system according to claim 1, wherein: The rust inhibitor is dodecenylsuccinic acid half ester.

3. The lubricating oil composition for a new energy electric vehicle transmission system according to claim 1, wherein: The metal deactivator is a liquid methylbenzotriazole derivative.

4. The method for preparing a lubricating oil composition for a new energy electric vehicle transmission system according to any one of claims 1 to 3, characterized in that: Specifically: Add anti-wear agent, rust inhibitor, metal deactivator and pour point depressant to the base oil and mix at 60-90℃ for 2-5h until the components are evenly dissolved in the base oil.

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