Tram wheel hub bearing grease and method for its production

Abstract

The present application relates to the technical field of lubricating grease, in particular to a trolley wheel hub bearing lubricating grease and a preparation method thereof.The trolley wheel hub bearing lubricating grease comprises the following raw materials in percentage by mass: base oil 70-82.7%, lithium-based thickening agent 8-11.2%, lignin sulfonate 1.5-3%, beeswax 2-4%, beta-type semi-hydrated calcium sulfate whisker 1.5-2%, extreme pressure anti-wear agent 0.5-1%, and rust inhibitor 0.5-1.8%.The lithium-based thickening agent is a composite lithium-based thickening agent formed by saponification of 12-hydroxystearic acid and palmitic acid with lithium hydroxide.The present application can effectively improve the high-temperature stability and lubricating performance of the lubricating grease.

Description

Technical Field

[0001] This invention relates to the field of grease technology, and in particular to a lubricating grease for electric vehicle wheel hub bearings and its preparation method. Background Technology

[0002] Wheel bearings, as a key component between the wheel and axle, play a crucial role in supporting the weight of the wheel and ensuring its smooth rotation relative to the axle. Compared to traditional gasoline-powered vehicles, electric vehicle wheel bearings need to withstand higher temperatures, placing greater demands on their heat resistance. As the lubricant used in wheel bearing operation, the performance of grease directly affects the bearing's efficiency and lifespan. Traditional wheel bearing greases often deteriorate under harsh high-temperature conditions, leading to poor lubrication and further accelerating wear and shortening the bearing's lifespan. Therefore, developing a grease for electric vehicle wheel bearings that can withstand high and even extreme high-temperature conditions is essential. Summary of the Invention

[0003] To obtain a lubricating grease for electric vehicle wheel hub bearings that can withstand high temperatures and even extreme high-temperature conditions, this application provides a lubricating grease for electric vehicle wheel hub bearings and its preparation method. This application, through specific raw material ratios and preparation methods, can effectively improve the high-temperature stability and lubrication performance of the grease.

[0004] Firstly, the electric vehicle wheel hub bearing lubricant provided in this application adopts the following technical solution:

[0005] A lubricating grease for electric vehicle wheel hub bearings comprises the following raw materials in weight percentages: 70%–82.7% base oil, 8%–11.2% lithium-based thickener, 1.5%–3% lignin sulfonate, 2%–4% beeswax, 1.5%–2% β-type hemihydrate calcium sulfate whiskers, 0.5%–1% extreme pressure anti-wear agent, and 0.5%–1.8% rust inhibitor; wherein the lithium-based thickener is a composite lithium-based thickener formed by saponification of 12-hydroxystearic acid and palmitic acid with lithium hydroxide.

[0006] In the above technical solution, this application achieves good high-temperature stability and lubrication performance in the prepared grease through the specific raw material ratios. Specifically, the base oil, as the main component of the grease, has a content between 70% and 82.7%, providing good fluidity and adhesion. Simultaneously, palmitic acid is added during the preparation of the lithium-based thickener. The lithium-based thickener formed by palmitic acid and 12-hydroxystearic acid effectively increases the consistency of the grease and improves its stability at high temperatures. Lignosulfonate, as a dispersant, has a content between 1.5% and 3%, which not only helps improve the dispersibility and stability of the grease but also effectively inhibits its high-temperature degradation. Beeswax further assists in... Thickening and improving the high-temperature stability of the grease reduces base oil loss and ensures the grease's performance at high temperatures; β-type calcium sulfate hemihydrate whiskers, as a solid lubricant, not only form a lubricating film on the friction surface of the wheel hub bearing, reducing friction and wear, but also act as a strong physical support network, preventing the grease from deteriorating under high-temperature conditions and thus reducing its performance. In addition, the addition of extreme pressure anti-wear agents and rust inhibitors further enhances the extreme pressure anti-wear and rust-preventive properties of the grease, further ensuring its stability and durability under extreme conditions.

[0007] Preferably, the mass ratio of 12-hydroxystearic acid, palmitic acid and lithium hydroxide is 100:(10-13):(29-33).

[0008] In the above technical solution, this application controls the mass ratio of 12-hydroxystearic acid, palmitic acid and lithium hydroxide within the above preferred range, so that the prepared grease has better high-temperature stability and lubrication performance.

[0009] Preferably, the base oil is a naphthenic mineral oil.

[0010] In the above technical solution, this application uses naphthenic mineral oil as the base oil mainly because naphthenic mineral oil has good thermal stability and oxidation resistance, which can maintain the good performance of grease under high temperature conditions, reduce the oxidative decomposition of grease at high temperature, and thus extend the service life of grease.

[0011] Preferably, the β-type calcium sulfate hemihydrate whiskers have a length of 5–20 μm and a diameter of 0.1–1 μm.

[0012] In the aforementioned technical solution, this application controls the length of β-type calcium sulfate hemihydrate whiskers to 5–20 μm and maintains the diameter within the range of 0.1–1 μm. This microstructure allows for uniform dispersion in the grease, more effectively forming a lubricating film and enhancing the mechanical strength and wear resistance of the grease. Furthermore, β-type calcium sulfate hemihydrate whiskers of this size can better embed into the friction surface of the wheel hub bearing, providing a lasting lubrication effect, reducing heat generated by friction, and further improving the stability of the grease under high-temperature environments.

[0013] Preferably, the β-type calcium sulfate hemihydrate crystals are surface-modified β-type calcium sulfate hemihydrate whiskers that have undergone surface modification treatment; wherein the surface modifier is a titanate coupling agent.

[0014] In the above technical solution, this application uses a titanate coupling agent to modify the surface of β-type calcium sulfate hemihydrate whiskers, which enhances the compatibility and bonding force between β-type calcium sulfate hemihydrate whiskers and other components in the grease, so that β-type calcium sulfate hemihydrate whiskers can be better dispersed in the grease system, further improving the uniformity and high-temperature stability of the grease.

[0015] Preferably, the surface modification treatment steps include: first dispersing β-type calcium sulfate hemihydrate whiskers in an 80wt% ethanol aqueous solution, then adding 0.3wt% to 0.5wt% titanate coupling agent to the solution, then stirring and reacting at 60℃ to 80℃ for 2 to 4 hours, and finally centrifuging, washing, and drying to obtain surface-modified β-type calcium sulfate hemihydrate whiskers.

[0016] Preferably, the electric vehicle wheel hub bearing grease further includes 0.5% to 1% phenyl salicylate.

[0017] Preferably, the mass ratio of phenyl salicylate to lignin sulfonate is 1:4.

[0018] In the above technical solution, this application further adds phenyl salicylate to the grease. As an antioxidant, phenyl salicylate can effectively improve the antioxidant properties of the grease, further extend the service life of the grease, and further enhance the high-temperature stability of the grease and reduce the high-temperature degradation of the grease through the synergistic effect with lignin sulfonate.

[0019] Preferably, the extreme pressure anti-wear agent is one or more of molybdenum disulfide, zinc dialkyl dithiophosphate, or isobutylene sulfide.

[0020] Preferably, the rust inhibitor is barium petroleum sulfonate.

[0021] Secondly, this application provides a method for preparing lubricating grease for electric vehicle wheel hub bearings, which adopts the following technical solution:

[0022] A method for preparing a lubricating grease for electric vehicle wheel hub bearings includes the following steps:

[0023] Step 1: Mix 30% by weight of the base oil with 12-hydroxystearic acid and palmitic acid and stir until homogeneous to obtain a mixed solution;

[0024] Step 2: Prepare a 20wt% lithium hydroxide aqueous solution by adding lithium hydroxide to water, and add it to the mixed solution obtained in Step 1 to carry out a saponification reaction; the saponification temperature is 105-115℃, and the saponification time is 2-2.5h;

[0025] Step 3: Heat to 195-200℃, dehydrate at -0.08 to -0.05MPa for 1-1.5 hours, then rapidly cool to below 150℃;

[0026] Step 4: Continue cooling to 90-95℃, add lignin sulfonate, and stir for 20-25 minutes;

[0027] Step 5: Cool down to below 75℃, add β-type hemihydrate calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4500-5000 rpm for 30 minutes and grind 1-3 times, then degas under vacuum to obtain electric vehicle wheel hub bearing grease.

[0028] Preferably, it includes the following steps:

[0029] Step 1: Mix 30% by weight of the base oil with 12-hydroxystearic acid and palmitic acid and stir until homogeneous to obtain a mixed solution;

[0030] Step 2: Prepare a 20wt% lithium hydroxide aqueous solution by adding lithium hydroxide to water, and add it to the mixed solution obtained in Step 1 to carry out a saponification reaction; the saponification temperature is 105-115℃, and the saponification time is 2-2.5h;

[0031] Step 3: Heat to 195-200℃, dehydrate at -0.08 to -0.05MPa for 1-1.5 hours, then rapidly cool to below 150℃;

[0032] Step 4: Continue cooling to 90-95℃, add lignin sulfonate and phenyl salicylate, and stir for 20-25 minutes;

[0033] Step 5: Cool down to below 75℃, add β-type hemihydrate calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4500-5000 rpm for 30 minutes and grind 1-3 times, then degas under vacuum to obtain electric vehicle wheel hub bearing grease.

[0034] In summary, this application includes at least one of the following beneficial technical effects:

[0035] 1. This application utilizes a specific raw material ratio, particularly by adding palmitic acid in the preparation of the lithium-based thickener. The lithium-based thickener formed by palmitic acid and 12-hydroxystearic acid can effectively increase the viscosity of the grease and improve its stability at high temperatures. Lignosulfonate, as a dispersant, with a content between 1.5% and 3%, not only helps improve the dispersibility and stability of the grease but also effectively inhibits its high-temperature degradation. Beeswax further assists in thickening and improving the high-temperature stability of the grease, reducing base oil loss and ensuring the working performance of the grease at high temperatures. β-type calcium sulfate hemihydrate whiskers, as a solid lubricant, not only form a lubricating film on the friction surface of the wheel hub bearing, reducing friction and wear, but also act as a strong physical support network, preventing the grease from deteriorating under high-temperature conditions and causing a decrease in working performance.

[0036] 2. The addition of extreme pressure anti-wear agents and rust inhibitors can further improve the extreme pressure anti-wear and rust prevention properties of the grease, and further ensure the stability and durability of the grease under extreme conditions.

[0037] 3. This application further adds phenyl salicylate to the grease. As an antioxidant, phenyl salicylate can effectively improve the antioxidant properties of the grease, further extend the service life of the grease, and through the synergistic effect with lignin sulfonate, further enhance the high-temperature stability of the grease and further reduce the high-temperature degradation of the grease. Detailed Implementation

[0038] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0039] Example 1

[0040] A lubricating grease for electric vehicle wheel hub bearings comprises: 82.5g base oil, 8g lithium-based thickener, 1.5g lignin sulfonate, 4g beeswax, 1.5g β-type calcium sulfate hemihydrate whiskers, 1g extreme pressure anti-wear agent, 0.5g rust inhibitor, and 1g phenyl salicylate.

[0041] The lithium-based thickener is a composite lithium-based thickener formed by saponification of 12-hydroxystearic acid and palmitic acid with lithium hydroxide.

[0042] The mass ratio of 12-hydroxystearic acid, palmitic acid and lithium hydroxide is 100:10:29.

[0043] The extreme pressure anti-wear agent is zinc dialkyl dithiophosphate.

[0044] The rust inhibitor is barium petroleum sulfonate.

[0045] The base oil is a naphthenic mineral oil.

[0046] The naphthenic mineral oil was purchased from Hengshui Diyi Petrochemical Co., Ltd., and its model number is 4016 naphthenic oil.

[0047] Palmitic acid was purchased from Guangzhou Zouyang Chemical Co., Ltd.

[0048] Among them, calcium lignosulfonate was purchased from Shandong Duoju Chemical Co., Ltd., CAS No.: 8061-52-7.

[0049] The beeswax was purchased from Henan Hengxincheng Chemical Products Co., Ltd.

[0050] Among them, the β-type calcium sulfate hemihydrate whiskers were purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0051] Zinc dialkyl dithiophosphate was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0052] The barium petroleum sulfonate was purchased from Guangzhou Zouyang Chemical Co., Ltd.

[0053] Among them, phenyl salicylate was purchased from Wuhan Linqing Biotechnology Co., Ltd.

[0054] The preparation method of electric vehicle wheel hub bearing grease includes the following steps:

[0055] Step 1: Mix 30% of the base oil (by weight of the formula) with 12-hydroxystearic acid and palmitic acid and stir until homogeneous to obtain a mixed solution.

[0056] Step 2: Prepare a 20wt% lithium hydroxide aqueous solution by adding lithium hydroxide to water, and add it to the mixed solution obtained in Step 1 to carry out a saponification reaction. The saponification temperature is 105℃, and the solution is saponified until it becomes a transparent gel.

[0057] Step 3: Heat to 195℃, dehydrate at -0.05MPa for 1 hour, and then rapidly cool to below 150℃.

[0058] Step 4: Continue cooling to 90℃, add lignin sulfonate and phenyl salicylate, and stir for 25 minutes.

[0059] Step 5: Cool down to below 75℃, add β-type hemihydrate calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 5000rpm for 30min and grind 3 times, then degas under vacuum to obtain electric vehicle wheel hub bearing grease.

[0060] Example 2

[0061] A lubricating grease for electric vehicle wheel hub bearings, which differs from Example 1, comprises: 80.4g base oil, 10g lithium-based thickener, 2g lignin sulfonate, 3g beeswax, 1.8g β-type calcium sulfate hemihydrate whiskers, 0.8g extreme pressure anti-wear agent, 1.2g rust inhibitor, and 0.8g phenyl salicylate.

[0062] The lithium-based thickener is a composite lithium-based thickener formed by saponification of 12-hydroxystearic acid and palmitic acid with lithium hydroxide.

[0063] The mass ratio of 12-hydroxystearic acid, palmitic acid and lithium hydroxide is 100:12:32.

[0064] The preparation method of electric vehicle wheel hub bearing grease includes the following steps:

[0065] Step 1: Mix 30% of the base oil (by weight of the formula) with 12-hydroxystearic acid and palmitic acid and stir until homogeneous to obtain a mixed solution.

[0066] Step 2: Prepare a 20wt% lithium hydroxide aqueous solution by adding lithium hydroxide to water, and add it to the mixed solution obtained in Step 1 to carry out a saponification reaction. The saponification temperature is 110℃, and the solution is saponified into a transparent gel.

[0067] Step 3: Heat to 198℃, dehydrate at -0.07MPa for 1.2 hours, and then rapidly cool to below 150℃.

[0068] Step 4: Continue cooling to 92℃, add lignin sulfonate and phenyl salicylate, and stir for 25 minutes.

[0069] Step 5: Cool down to below 75℃, add β-type hemihydrate calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4800rpm for 30min and grind 3 times, then degas under vacuum to obtain electric vehicle wheel hub bearing grease.

[0070] Example 3

[0071] A lubricating grease for electric vehicle wheel hub bearings, which differs from Example 1, comprises: 79g base oil, 11.2g lithium-based thickener, 3g lignin sulfonate, 2g beeswax, 2g β-type calcium sulfate hemihydrate whiskers, 0.5g extreme pressure anti-wear agent, 1.8g rust inhibitor, and 0.5g phenyl salicylate.

[0072] The lithium-based thickener is a composite lithium-based thickener formed by saponification of 12-hydroxystearic acid and palmitic acid with lithium hydroxide.

[0073] The mass ratio of 12-hydroxystearic acid, palmitic acid and lithium hydroxide is 100:13:33.

[0074] The preparation method of electric vehicle wheel hub bearing grease includes the following steps:

[0075] Step 1: Mix 30% of the base oil (by weight of the formula) with 12-hydroxystearic acid and palmitic acid and stir until homogeneous to obtain a mixed solution.

[0076] Step 2: Prepare a 20wt% lithium hydroxide aqueous solution by adding lithium hydroxide to water, and add it to the mixed solution obtained in Step 1 to carry out a saponification reaction. The saponification temperature is 115℃, and the solution is saponified into a transparent gel.

[0077] Step 3: Heat to 200℃, dehydrate at -0.08MPa for 1.5h, and then rapidly cool to below 150℃.

[0078] Step 4: Continue cooling to 90℃, add lignin sulfonate and phenyl salicylate, and stir for 20 minutes.

[0079] Step 5: Cool down to below 75℃, add β-type hemihydrate calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 5000rpm for 30min and grind 3 times, then degas under vacuum to obtain electric vehicle wheel hub bearing grease.

[0080] Example 4

[0081] A lubricating grease for electric vehicle wheel hub bearings differs from Example 3 in that the amount of lignin sulfonate is changed to 2g and the amount of base oil is changed to 80g.

[0082] Example 5

[0083] A lubricating grease for electric vehicle wheel hub bearings, which differs from Example 3 in that it does not contain phenyl salicylate.

[0084] Example 6

[0085] A type of electric vehicle wheel hub bearing grease, which differs from Example 3 in that the β-type calcium sulfate hemihydrate crystals are surface-modified β-type calcium sulfate hemihydrate whiskers that have undergone surface modification treatment.

[0086] The surface modifier is a titanate coupling agent.

[0087] The surface modification process includes: first, dispersing β-type calcium sulfate hemihydrate whiskers in an 80wt% ethanol aqueous solution; then, adding 0.4wt% titanate coupling agent to the solution; then, stirring the reaction at 70℃ for 3 hours; and finally, centrifuging, washing, and drying to obtain surface-modified β-type calcium sulfate hemihydrate whiskers.

[0088] Comparative Example 1

[0089] A lubricating grease for electric vehicle wheel hub bearings, which differs from Example 5 in that palmitic acid is replaced with boric acid in equal amounts.

[0090] Comparative Example 2

[0091] A lubricating grease for electric vehicle wheel hub bearings, which differs from Example 5 in that lignin sulfonate is replaced in equal amounts with sodium dodecylbenzene sulfonate.

[0092] Comparative Example 3

[0093] A lubricating grease for electric vehicle wheel hub bearings, which differs from Example 5 in that beeswax is replaced with an equal amount of paraffin wax.

[0094] Comparative Example 4

[0095] A lubricating grease for electric vehicle wheel hub bearings, which differs from Example 5 in that it does not contain β-type calcium sulfate hemihydrate whiskers.

[0096] Performance testing

[0097] The detection indicators are shown in Table 1.

[0098] Table 1:

[0099] Physicochemical indicators Measurement Standards Working taper depth / 0.1mm GB / T269 Water loss (79℃, 1h) / % SH / T0109 Dropping point / ℃ GB / T3498 <![CDATA[Apparent viscosity (-20 °C, 10 s -1 ) / Pa·s]]> SH / T0048 Oil separation of steel mesh (100℃, 24h) / % NB / SH / T0324

[0100] The test results are shown in Table 2.

[0101] Table 2:

[0102]

[0103] Based on the analysis of Examples 1-6, Comparative Examples 1-4 and Table 2, it can be seen that the greases of Examples 1 to 6 exhibit good working cone penetration, low water leaching, high dropping point, suitable similar viscosity and low stencil oil separation rate. This shows that the greases of Examples 1-6 have good high temperature resistance.

[0104] Compared with Example 3, the surface-modified β-type calcium sulfate hemihydrate whiskers in Example 6 further optimized the dropping point and similar viscosity of the grease, while the oil separation rate of the steel mesh was zero, showing better stability and high temperature resistance.

[0105] Compared to Example 5, in Comparative Examples 1 to 4, the performance of the grease decreased after replacing or removing palmitic acid, lignin sulfonate, beeswax, and β-type calcium sulfate hemihydrate whiskers, respectively. In Comparative Example 1, the dropping point of the grease decreased significantly, the similar viscosity increased, and the oil separation rate of the stencil increased after boric acid replaced palmitic acid. In Comparative Example 2, the water leaching of the grease increased, the dropping point decreased, the similar viscosity increased, and the oil separation rate of the stencil increased after sodium dodecylbenzene sulfonate replaced lignin sulfonate. In Comparative Example 3, the dropping point of the grease decreased somewhat after paraffin replaced beeswax, the similar viscosity increased, and the oil separation rate of the stencil increased. In Comparative Example 4, the dropping point of the grease decreased significantly, the similar viscosity increased significantly, and the oil separation rate of the stencil increased substantially after removing β-type calcium sulfate hemihydrate whiskers. Therefore, it is evident that only with the specific raw material ratios of this application can a high-performance electric vehicle wheel hub bearing grease be prepared. These components play an indispensable role in the formulation, synergistically improving the high-temperature resistance of the grease.

[0106] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A lubricating grease for electric vehicle wheel hub bearings, characterized in that, The raw materials include the following percentages by weight: base oil 70%–82.7%, lithium-based thickener 8%–11.2%, lignosulfonate 1.5%–3%, beeswax 2%–4%, β-type calcium sulfate hemihydrate whiskers 1.5%–2%, extreme pressure anti-wear agent 0.5%–1%, and rust inhibitor 0.5%–1.8%; the sum of the percentages by weight of each component is 100%, wherein the lithium-based thickener is a composite lithium-based thickener formed by saponification of 12-hydroxystearic acid and palmitic acid with lithium hydroxide; The β-type calcium sulfate hemihydrate whiskers have a length of 5–20 μm and a diameter of 0.1–1 μm; the β-type calcium sulfate hemihydrate whiskers are surface-modified β-type calcium sulfate hemihydrate whiskers that have undergone surface modification treatment; wherein, the surface modifier is a titanate coupling agent; The surface modification process includes: first, dispersing β-type calcium sulfate hemihydrate whiskers in an 80wt% ethanol aqueous solution; then, adding 0.3wt% to 0.5wt% titanate coupling agent to the solution; then, stirring and reacting at 60℃ to 80℃ for 2 to 4 hours; and finally, centrifuging, washing, and drying to obtain surface-modified β-type calcium sulfate hemihydrate whiskers.

2. The electric vehicle wheel hub bearing grease according to claim 1, characterized in that, The mass ratio of 12-hydroxystearic acid, palmitic acid and lithium hydroxide is 100:(10-13):(29-33).

3. The electric vehicle wheel hub bearing grease according to claim 1, characterized in that, The base oil is a naphthenic mineral oil.

4. The electric vehicle wheel hub bearing grease according to claim 1, characterized in that, The electric vehicle wheel hub bearing grease also includes 0.5% to 1% phenyl salicylate.

5. The electric vehicle wheel hub bearing grease according to claim 4, characterized in that, The mass ratio of phenyl salicylate to lignin sulfonate is 1:

4.

6. A method for preparing a lubricating grease for electric vehicle wheel hub bearings as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Mix 30% by weight of the base oil with 12-hydroxystearic acid and palmitic acid and stir until homogeneous to obtain a mixed solution; Step 2: Prepare a 20wt% lithium hydroxide aqueous solution by adding lithium hydroxide to water, and add it to the mixed solution obtained in Step 1 to carry out a saponification reaction; the saponification temperature is 105-115℃, and the saponification time is 2-2.5h; Step 3: Heat to 195-200℃, dehydrate at -0.08 to -0.05MPa for 1-1.5 hours, then rapidly cool to below 150℃; Step 4: Continue cooling to 90-95℃, add lignin sulfonate, and stir for 20-25 minutes; Step 5: Cool down to below 75℃, add β-type hemihydrate calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4500-5000 rpm for 30 minutes and grind 1-3 times, then degas under vacuum to obtain electric vehicle wheel hub bearing grease.

7. The method for preparing electric vehicle wheel hub bearing grease according to claim 6, characterized in that, Includes the following steps: Step 1: Mix 30% by weight of the base oil with 12-hydroxystearic acid and palmitic acid and stir until homogeneous to obtain a mixed solution; Step 2: Prepare a 20wt% lithium hydroxide aqueous solution by adding lithium hydroxide to water, and add it to the mixed solution obtained in Step 1 to carry out a saponification reaction; the saponification temperature is 105-115℃, and the saponification time is 2-2.5h; Step 3: Heat to 195-200℃, dehydrate at -0.08 to -0.05MPa for 1-1.5 hours, then rapidly cool to below 150℃; Step 4: Continue cooling to 90-95℃, add lignin sulfonate and phenyl salicylate, and stir for 20-25 minutes; Step 5: Cool down to below 75℃, add β-type hemihydrate calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4500-5000 rpm for 30 minutes and grind 1-3 times, then degas under vacuum to obtain electric vehicle wheel hub bearing grease.

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