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

Abstract

The invention discloses a lubricating oil composition for a transmission system of a new energy electric vehicle. The lubricating oil composition comprises the following components in percentage by mass: 0.01-2% of an anti-wear agent; 0.01-2% of an antirust agent; 0.01-1% of a metal deactivator; 0-3% of a pour point depressant; the sum of the mass percentages of the components is 100%. The invention also discloses a preparation method of the lubricating oil composition, which specifically comprises the following steps: adding the anti-wear agent, the antirust agent, the metal deactivator and the pour point depressant into the base oil, and blending until the components are uniformly dissolved in the base oil. By expanding the side chain of BTTP, three siloxane structures are introduced, so that the BTTP has excellent solubility and better wear resistance in fluorine-containing silicone oil. Besides, the lubricating oil composition adopting a fluorosilicone oil base oil formula has good low-temperature fluidity, oxidation resistance and electrochemical performance, and can meet the requirements of lubrication and cooling of an oil-cooled motor reduction gearbox transmission system.

Description

Technical Field

[0001] The present invention belongs to the technical field of lubricating oils, and in particular relates to a lubricating oil composition for a transmission system of a new energy electric vehicle, and also relates to a method for preparing the lubricating oil composition. Background Art

[0002] According to the cooling method, the transmission system of new energy vehicles is divided into water-cooled motor reducer system and oil-cooled motor reducer system. Compared with water-cooled motors, oil-cooled motors can directly cool the winding ends with the highest temperature, especially the flat wire windings with larger exposed areas at the cooling ends, and can actively cool the internal rotor components; at the same time, the oil-cooled motor reducer 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 the oil improves the lubrication stirring efficiency, and heating the battery and other components improves the heat utilization efficiency. Therefore, oil-cooled motors have the advantage of miniaturization compared to water-cooled motors and have very broad technical prospects. However, this also means that the lubricating oil composition used in the oil-cooled motor reducer transmission system must not only have excellent low-temperature performance and antioxidant properties, but also have good specific heat capacity, thermal conductivity and electrochemical properties to meet the needs of the oil-cooled motor reducer transmission system.

[0003] A Chinese patent (application number: 201910813451.X, publication number: CN 112442412 A) discloses a lubricating oil composition for a hybrid vehicle gearbox, the composition comprising 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 hybrid vehicle gearboxes, and can therefore be used as a lubricating oil for hybrid vehicle gearboxes. The resulting lubricating oil has excellent low temperature performance, extreme pressure anti-wear properties, antioxidant properties, and anti-rust and anti-corrosion properties. Compared with ordinary gear oil products, the lubricating oil of the invention composition, in addition to having excellent anti-wear and antioxidant properties, has excellent electrochemical properties, is more suitable for hybrid vehicle gearboxes, and has simple ingredients and a simple manufacturing process.

[0004] Chinese patent (application number: 201711038962.6, publication number: CN107828481B) discloses a lubricating oil composition for electric vehicle gearbox and its preparation method, including the following components in weight percentage: base oil 79.8-84.5%, polymethacrylate viscosity index agent 4-7%, gearbox oil special compounding agent 10-13%, pour point depressant 0.3-0.5%; polymethacrylate viscosity index agent is a comb polymer, and the shear stability index of the viscosity index agent is not more than 28. The advantage of this invention is that the viscosity of the prepared oil remains unchanged under the action of long-term high-speed shear force, providing reliable protection for electric vehicle gearboxes, having excellent shear stability, outstanding low-temperature rheology and can greatly improve the high-temperature thickening ability of the oil at a lower dosage, having good dispersibility, reducing the deposition of oil oxides, and being used in conjunction with the gearbox special compounding agent to improve the cleaning and dispersing performance of the oil.

[0005] A Chinese patent (application number: 201510580512.4, publication number: CN105132107A) discloses a lubricating oil composition for a pure electric vehicle gearbox. 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 ash-free 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 product can meet the lubrication requirements of gears and bearings in pure electric vehicle gearboxes, 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 composition for electric vehicles or hybrid vehicles, which provides a lubricant composition for electric vehicles or hybrid vehicles with excellent gear characteristics, clutch characteristics, cooling properties and electrical insulation properties. The lubricant composition for electric vehicles or hybrid vehicles is formulated with (A) base oil, and (B-1) polyamide and / or (B-2) polyol ester, as the aforementioned (A) base oil, including (A-1) 100°C kinematic viscosity of 1.0 to 10.0 mm 2 / s of synthetic oil.

[0007] None of the above invention patents involve the use of fluorinated silicone base oil in the lubricating oil composition of the oil-cooled motor reducer transmission system, nor are there any related reports. Silicone oil has good low-temperature flow properties, high-temperature thermal oxidation stability, etc. Introducing fluorocarbon groups into silicone oil can not only maintain the original excellent properties of silicone oil, but also improve lubrication performance. Summary of the invention

[0008] The purpose of the present invention is to provide a lubricating oil composition for a new energy electric vehicle transmission system, wherein the lubricating oil composition has good low-temperature fluidity, anti-oxidation performance and electrochemical performance.

[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 according to mass percentage: 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 mass percentages 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:

[0014] Hexamethylcyclotrisiloxane and BTTP were mixed in a molar ratio of 3:1, heated in an oil bath to 50-85°C and reacted at this temperature for 1-4 hours, then heated to 90-100°C and reacted for 2-5 hours, and cooled to room temperature to obtain an oily transparent product, which is modified butyl triphenyl thiophosphate.

[0015] The rust inhibitor is dodecenyl succinate 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°C for 2-5 hours 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 using the fluorosilicone oil base oil formula has good low-temperature fluidity, antioxidant performance and electrochemical performance, 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 diagram of the structure of butyl triphenyl thiophosphate;

[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 It is a diagram of the reaction equation of hexamethylcyclotrisiloxane and BTTP. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with specific implementation modes and accompanying drawings.

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

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

[0028] The rust inhibitor is dodecenyl succinate 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-alpha-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 PO and P=S anti-wear components, and at the same time expands the side chain of BTTP, introduces Si-O groups, and increases 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 extends the side chain of BTTP and introduces three siloxane structures, so that it has excellent solubility in fluorinated silicone oil, while its own P=S, PO and other groups remain unchanged to maintain its own good anti-wear performance.

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

[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, and cool to room temperature to obtain an oily transparent product, namely BTTP-Si-O. The reaction equation is as follows: Figure 4 As shown;

[0037] The preparation method of the lubricating oil composition for the transmission system of new energy electric vehicles of the present invention is specifically as follows: adding an anti-wear agent, a rust inhibitor, a metal deactivator and a pour point depressant into a base oil, and mixing 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 by Examples 1-5 are shown in Table 6:

[0060] Table 6 Oil test results

[0061]

[0062]

[0063] It can be seen from Table 6 that the oil product blended with the fluorinated silicone oil base oil formula of Example 1 has excellent viscosity index performance, low-temperature flowability and high-temperature antioxidant performance, good cooling performance and electrochemical performance, which are far superior to competing products developed with 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 advantages that the unmodified anti-wear agent is insoluble in the silicone oil base oil, while the modified anti-wear agent BTTP-Si-O is very easily soluble in the silicone oil base oil. After adding BTTP-Si-O, the oil formula containing fluorinated silicone oil has good anti-wear performance.

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

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

[0067]

[0068]

[0069] It can be seen from Table 7 that the volume resistivity of the fluorinated silicone base oil formula of Example 1 is significantly higher than that of competing products, and the electrochemical insulation performance is excellent; Example 1 has an extremely high viscosity index and the low-temperature flow performance (low-temperature viscosity) and high-temperature antioxidant stability (100°C viscosity reduction rate) are also better than those of competing products; the FZG gear abrasion test failure level of Example 1 is level 6, achieving anti-wear performance comparable to that of 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 lubricating oil composition has very excellent low-temperature fluidity, high-temperature antioxidant properties and electrochemical insulation properties, and its low-temperature performance and life far exceed those of competing products on the market, and its anti-wear performance is comparable to those 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 invention comprises the following components in terms of mass percentage: 0.01-2% anti-wear agent; 0.01-2% anti-rust agent; 0.01-1% metal deactivator; 0-3% pour point depressant; the balance is base oil, and the sum of the mass percentages of the above components is 100%.

2. The lubricating oil composition for a new energy electric vehicle transmission system according to claim 1, characterized in that: The anti-wear agent is modified butyl triphenyl thiophosphate.

3. The lubricating oil composition for the transmission system of a new energy electric vehicle according to claim 2, characterized in that: The preparation method of the modified butyl triphenyl thiophosphate is: Hexamethylcyclotrisiloxane and BTTP were mixed in a molar ratio of 3:1, heated in an oil bath to 50-85°C and reacted at this temperature for 1-4 hours, then heated to 90-100°C and reacted for 2-5 hours, and cooled to room temperature to obtain an oily transparent product, which is modified butyl triphenyl thiophosphate.

4. The lubricating oil composition for a new energy electric vehicle transmission system according to claim 1, characterized in that: The rust inhibitor is dodecenyl succinic acid half ester.

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

6. The lubricating oil composition for a new energy electric vehicle transmission system according to claim 1, characterized in that: 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.

7. The method for preparing a lubricating oil composition for a new energy electric vehicle transmission system according to any one of claims 1 to 6, 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°C for 2-5 hours until the components are evenly dissolved in the base oil.

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