Trolley hub bearing lubricating grease and preparation method thereof

Abstract

The invention relates to the technical field of lubricating grease, in particular to electric car hub bearing lubricating grease and a preparation method thereof. The lubricating grease comprises the following raw materials in percentage by mass: 70%-82.7% of base oil, 8%-11.2% of a lithium-based thickening agent, 1.5%-3% of lignosulfonate, 2%-4% of beewax, 1.5%-2% of beta-type calcium sulfate hemihydrate whiskers, 0.5%-1% of an anti-wear reagent at extreme pressure and 0.5%-1.8% of an anti-rust agent, wherein the lithium-based thickening agent is a composite lithium-based thickening agent formed by saponifying 12-hydroxystearic acid and palmitic acid through lithium hydroxide. The high-temperature stability and lubricating property of the lubricating grease can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating grease, in particular to a lubricating grease for a wheel hub bearing of an electric vehicle and a preparation method thereof. Background Art

[0002] The hub bearing, as one of the key components between the wheel and the axle, has the core function of supporting the weight of the wheel and ensuring that it can rotate smoothly relative to the axle. Compared with traditional fuel vehicles, the hub bearings of electric vehicles need to withstand a higher temperature working environment, which places higher demands on the heat resistance of the hub bearings. Grease is a lubricant in the working process of the hub bearing, and its performance directly affects the working efficiency and life of the hub bearing. Traditional hub bearing grease often deteriorates under harsh conditions of high temperature, resulting in negative effects such as poor lubrication effect, which further leads to increased wear of the hub bearing and shortened service life. Therefore, it is very necessary to develop an electric vehicle hub bearing grease that can adapt to high temperature or even extreme high temperature conditions. Summary of the Invention

[0003] To obtain an electric vehicle hub bearing grease that can withstand high or even extreme high temperature conditions, this application provides an electric vehicle hub bearing grease and a preparation method thereof. This application utilizes a specific raw material ratio and preparation method to effectively improve the high-temperature stability and lubrication performance of the grease.

[0004] In the first aspect, the present application provides a trolley hub bearing grease adopting the following technical solution:

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

[0006] In the technical solution, the specific raw material ratio is used to make the prepared grease have good high-temperature stability and lubricating performance. Specifically, the base oil, as the main component of the grease, has a content of 70% to 82.7%, which provides good flowability and adhesion for the grease. Meanwhile, the lithium-based thickening agent prepared by adding palmitic acid and 12-hydroxystearic acid can effectively increase the consistency of the grease and improve the stability of the grease at high temperatures. The lignosulfonate, as a dispersant, has a content of 1.5% to 3%, which can improve the dispersibility and stability of the grease, effectively inhibit the high-temperature degradation of the grease, and further assist thickening and improve the high-temperature stability of the grease, reduce the loss of the base oil, and ensure the working performance of the grease at high temperatures. The beta-type calcium sulfate whisker, as a solid lubricant, can form a lubricating film on the friction surface of the hub bearing, reduce the friction and wear of the hub bearing, and play a strong physical support network role to avoid the degradation of the working performance of the grease at high temperatures. In addition, the addition of the extreme pressure anti-wear agent and the rust inhibitor can further improve the extreme pressure anti-wear performance and the rust resistance of the grease, and further ensure the stability and durability of the grease under extreme conditions.

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

[0008] In the technical solution, the mass ratio of the 12-hydroxystearic acid, the palmitic acid, and the lithium hydroxide is controlled within the preferred range, so that the prepared grease has more excellent high-temperature stability and lubricating performance.

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

[0010] In the technical solution, the naphthenic mineral oil is used as the base oil, mainly because the naphthenic mineral oil has good thermal stability and oxidation resistance, can maintain good performance of the grease at high temperatures, reduce oxidation and decomposition of the grease at high temperatures, and thus prolong the service life of the grease.

[0011] Preferably, the beta-type calcium sulfate whisker has a length of 5-20 μm and a diameter of 0.1-1 μm.

[0012] In the above technical solution, the present application controls the length of the β-calcium sulfate hemihydrate whiskers to 5-20 μm and the diameter to 0.1-1 μm. This microstructure enables them to be evenly dispersed in the grease, more effectively forming a lubricating film and enhancing the grease's mechanical strength and wear resistance. Furthermore, the β-calcium sulfate hemihydrate whiskers of this size can better embed into the friction surface of the hub bearing, providing a long-lasting lubrication effect, reducing heat generated by friction, and further improving the grease's stability in high-temperature environments.

[0013] Preferably, the β-calcium sulfate hemihydrate crystals are surface-modified β-calcium sulfate hemihydrate whiskers, wherein the surface modifier is a titanate coupling agent.

[0014] In the above technical solution, the present application uses a titanate coupling agent to perform surface modification treatment on β-calcium sulfate hemihydrate whiskers, thereby enhancing the compatibility and binding force between β-calcium sulfate hemihydrate whiskers and other components in the grease, so that the β-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 step includes: first dispersing β-calcium sulfate hemihydrate whiskers in 80wt% ethanol aqueous solution, then adding 0.3wt% to 0.5wt% titanate coupling agent to the solution, then stirring and reacting at 60°C to 80°C for 2 to 4 hours, and finally centrifuging, washing, and drying to obtain surface-modified β-calcium sulfate hemihydrate whiskers.

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

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

[0018] In the above technical solution, the present application further adds phenyl salicylate to the grease. Phenyl salicylate, as an antioxidant, 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 through synergistic action with lignin sulfonate, thereby further reducing the high-temperature degradation of the grease.

[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] In a second aspect, the present application provides a method for preparing electric vehicle hub bearing grease using the following technical solution:

[0022] A preparation method of a trolley wheel hub bearing grease, comprising the following steps:

[0023] Step 1: 30% of base oil by weight of the formula is mixed with 12-hydroxystearic acid and palmitic acid and stirred uniformly to obtain a mixed solution;

[0024] Step 2: lithium hydroxide is added to water to prepare a 20wt% lithium hydroxide aqueous solution, which is added to the mixed solution obtained in step 1 to perform a saponification reaction; the saponification temperature is 105-115 DEG C, and the saponification time is 2-2.5h;

[0025] Step 3: heated to 195-200 DEG C, dehydrated at -0.08 to -0.05 MPa for 1-1.5h, and then rapidly cooled to below 150 DEG C;

[0026] Step 4: continue to cool to 90-95 DEG C, add lignosulfonate, and stir for 20-25 min;

[0027] Step 5: cool to below 75 DEG C, add beta-type calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4500-5000 rpm for 30 min, then grind 1-3 times, and vacuum degas to obtain a trolley wheel hub bearing grease.

[0028] Preferably, the following steps are included:

[0029] Step 1: 30% of base oil by weight of the formula is mixed with 12-hydroxystearic acid and palmitic acid and stirred uniformly to obtain a mixed solution;

[0030] Step 2: lithium hydroxide is added to water to prepare a 20wt% lithium hydroxide aqueous solution, which is added to the mixed solution obtained in step 1 to perform a saponification reaction; the saponification temperature is 105-115 DEG C, and the saponification time is 2-2.5h;

[0031] Step 3: heated to 195-200 DEG C, dehydrated at -0.08 to -0.05 MPa for 1-1.5h, and then rapidly cooled to below 150 DEG C;

[0032] Step 4: continue to cool to 90-95 DEG C, add lignosulfonate and phenyl salicylate, and stir for 20-25 min;

[0033] Step 5: cool to below 75 DEG C, add beta-type calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4500-5000 rpm for 30 min, then grind 1-3 times, and vacuum degas to obtain a trolley wheel hub bearing grease.

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

[0035] 1. The application can effectively increase the consistency of the lubricating grease, improve the stability of the lubricating grease at high temperature, and the content of the lignosulfonate as a dispersant is between 1.5% and 3%, which helps to improve the dispersibility and stability of the lubricating grease, effectively inhibits the high-temperature degradation of the lubricating grease, and further assists thickening and improves the high-temperature stability of the lubricating grease, reduces the loss of base oil, and ensures the working performance of the lubricating grease at high temperature; the beta-type calcium sulfate whisker as a solid lubricant not only forms a lubricating film on the friction surface of the hub bearing to reduce the friction and wear of the hub bearing, but also plays a strong physical support network role to avoid the degradation of the lubricating grease at high temperature.

[0036] 2. The addition of extreme pressure anti-wear agent and rust inhibitor can further improve the extreme pressure anti-wear performance and rust prevention performance of the lubricating grease, and further ensure the stability and durability of the lubricating grease under extreme conditions.

[0037] 3. The application further adds phenyl salicylate to the lubricating grease, which can effectively improve the antioxidant performance of the lubricating grease, further prolong the service life of the lubricating grease, and further enhance the high-temperature stability of the lubricating grease through the synergistic effect of lignosulfonate, and further reduce the high-temperature degradation of the lubricating grease. DETAILED DESCRIPTION

[0038] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples.

[0039] Example 1

[0040] A trolley wheel hub bearing lubricating grease, comprising: base oil 82.5g, lithium-based thickening agent 8g, lignosulfonate 1.5g, beeswax 4g, beta-type calcium sulfate whisker 1.5g, extreme pressure anti-wear agent 1g, rust inhibitor 0.5g and phenyl salicylate 1g.

[0041] 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.

[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 dialkyldithiophosphate.

[0044] The rust inhibitor is barium petroleum sulfonate.

[0045] The base oil is naphthenic mineral oil.

[0046] Among them, naphthenic mineral oil was purchased from Hengshui Diyi Petrochemical Co., Ltd., model: 4016 naphthenic oil.

[0047] Among them, palmitic acid was purchased from Guangzhou Zouyang Chemical Co., Ltd.

[0048] Calcium lignin sulfonate was purchased from Shandong Poly Chemical Co., Ltd., CAS No.: 8061-52-7.

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

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

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

[0052] Among them, 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 method for preparing the electric vehicle hub bearing grease comprises the following steps:

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

[0056] Step 2: lithium hydroxide is added with water to prepare a 20 wt% lithium hydroxide aqueous solution, and the mixed solution obtained in step 1 is added to carry out saponification reaction at a saponification temperature of 105° C. until it becomes a transparent gel.

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

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

[0059] Step 5: Cool to below 75°C, add β-calcium sulfate hemihydrate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 5000 rpm for 30 minutes, grind three times, and vacuum degas to obtain electric wheel hub bearing grease.

[0060] Example 2

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

[0062] The lithium-based thickener is a composite lithium-based thickener formed by saponifying 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 method for preparing the electric vehicle hub bearing grease comprises the following steps:

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

[0066] Step 2: lithium hydroxide is added with water to prepare a 20 wt % lithium hydroxide aqueous solution, and the mixed solution obtained in step 1 is added to carry out saponification reaction at a saponification temperature of 110° C. until the solution becomes a transparent gel.

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

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

[0069] Step 5: Cool to below 75°C, add β-calcium sulfate hemihydrate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4800 rpm for 30 minutes, grind three times, and vacuum degas to obtain electric wheel hub bearing grease.

[0070] Example 3

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

[0072] The lithium-based thickener is a composite lithium-based thickener formed by saponifying 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 method for preparing the electric vehicle hub bearing grease comprises the following steps:

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

[0076] Step 2: Prepare a 20wt% aqueous lithium hydroxide solution by dissolving lithium hydroxide in water, and add it to the mixed solution obtained in Step 1 to perform saponification. The saponification temperature is 115°C, and the saponification is carried out until a transparent gel is formed.

[0077] Step 3: Increase the temperature to 200°C, dehydrate at -0.08 MPa for 1.5 hours, and then rapidly cool to below 150°C.

[0078] Step 4: Continue to cool to 90°C, add lignosulfonate and phenyl salicylate, and stir for 20 minutes.

[0079] Step 5: Cool to below 75°C, add β-type calcium sulfate whiskers, molten beeswax, extreme pressure anti-wear agent, and anti-rust agent, homogenize at 5000 rpm for 30 minutes, and then grind 3 times to obtain a trolley wheel hub bearing grease.

[0080] Example 4

[0081] A trolley wheel hub bearing grease, different from Example 3, is that the amount of lignosulfonate is changed to 2g, and the amount of base oil is changed to 80g.

[0082] Example 5

[0083] A trolley wheel hub bearing grease, different from Example 3, is that it does not contain phenyl salicylate.

[0084] Example 6

[0085] A trolley wheel hub bearing grease, different from Example 3, is that the β-type calcium sulfate whiskers are surface-modified β-type calcium sulfate whiskers.

[0086] Wherein, the surface modifier is a titanate coupling agent.

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

[0088] Comparative Example 1

[0089] A trolley wheel hub bearing grease, different from Example 5, is that palmitic acid is replaced by boric acid in equal amount.

[0090] Comparative Example 2

[0091] A grease for electric vehicle hub bearings, which differs from Example 5 in that an equal amount of lignin sulfonate is replaced by sodium dodecylbenzene sulfonate.

[0092] Comparative Example 3

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

[0094] Comparative Example 4

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

[0096] Performance testing

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

[0098] Table 1:

[0099] Physical and chemical indexes Measuring standard Working cone penetration / 0.1mm GB / T 269 Water rinsing loss(79℃,1h) / % SH / T 0109 Drop point / ℃ GB / T 3498 Similar viscosity (-20°C, 10 s -1 ) / Pa s SH / T 0048 Steel mesh oil separation(100℃,24h) / % NB / SH / T 0324

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

[0101] Table 2:

[0102]

[0103] Combining the analysis of Examples 1 to 6, Comparative Examples 1 to 4 and Table 2, it can be seen that the greases of Examples 1 to 6 exhibit good working penetration, low water runoff, high dropping point, suitable similar viscosity and low steel mesh oil separation rate. It can be seen that the greases of Examples 1 to 6 have good high temperature resistance.

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

[0105] Compared with Example 5, the performance of the greases in Comparative Examples 1 to 4 decreased after palmitic acid, lignin sulfonate, beeswax, and β-calcium sulfate hemihydrate whiskers were replaced or removed, respectively. In Comparative Example 1, after boric acid replaced palmitic acid, the dropping point of the grease was significantly reduced, the similar viscosity increased, and the oil separation rate of the steel mesh increased. In Comparative Example 2, after sodium dodecylbenzene sulfonate replaced lignin sulfonate, the water runoff of the grease increased, the dropping point decreased, the similar viscosity increased, and the oil separation rate of the steel mesh increased. In Comparative Example 3, after paraffin replaced beeswax, the dropping point of the grease decreased, the similar viscosity increased, and the oil separation rate of the steel mesh increased. In Comparative Example 4, after removing β-calcium sulfate hemihydrate whiskers, the dropping point of the grease was significantly reduced, the similar viscosity increased significantly, and the oil separation rate of the steel mesh increased significantly. It can be seen that only with the specific raw material ratio of this application can a high-performance electric vehicle hub bearing grease be prepared. These components play an indispensable role in the formula, synergizing with each other to jointly improve the high-temperature resistance of the grease.

[0106] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A grease for electric vehicle hub bearings, characterized in that: The invention comprises the following raw materials in percentage by mass: 70% to 82.7% of base oil, 8% to 11.2% of lithium-based thickener, 1.5% to 3% of lignin sulfonate, 2% to 4% of beeswax, 1.5% to 2% of beta-type calcium sulfate hemihydrate whisker, 0.5% to 1% of extreme pressure anti-wear agent, and 0.5% to 1.8% of rust inhibitor; wherein the lithium-based thickener is a composite lithium-based thickener formed by saponifying 12-hydroxystearic acid and palmitic acid with lithium hydroxide.

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

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

4. The electric wheel hub bearing grease according to claim 1, characterized in that: The beta-type calcium sulfate hemihydrate whiskers have a length of 5 to 20 μm and a diameter of 0.1 to 1 μm.

5. The electric vehicle hub bearing grease according to claim 4, characterized in that: The beta-type calcium sulfate hemihydrate crystals are surface-modified beta-type calcium sulfate hemihydrate whiskers that have undergone surface modification treatment; wherein the surface modifier is a titanate coupling agent.

6. The electric vehicle hub bearing grease according to claim 5, characterized in that: The surface modification treatment step includes: first dispersing beta-calcium sulfate hemihydrate whiskers in an 80wt% ethanol aqueous solution, then adding 0.3wt% to 0.5wt% of a titanate coupling agent to the solution, then stirring and reacting at 60°C to 80°C for 2 to 4 hours, and finally centrifuging, washing, and drying to obtain surface-modified beta-calcium sulfate hemihydrate whiskers.

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

8. The electric vehicle hub bearing grease according to claim 7, characterized in that: The mass ratio of the phenyl salicylate to the lignin sulfonate is 1:

4.

9. A method for preparing electric vehicle hub bearing grease according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Mixing 30% of the base oil by weight with 12-hydroxystearic acid and palmitic acid and stirring uniformly to obtain a mixed solution; Step 2: lithium hydroxide is added with water to prepare a 20 wt% lithium hydroxide aqueous solution, and the mixed solution obtained in step 1 is added to carry out a saponification reaction; the saponification temperature is 105-115° C., and the saponification time is 2-2.5 hours; Step 3: heating to 195-200°C, dehydrating at -0.08-0.05 MPa for 1-1.5 hours, and then rapidly cooling to below 150°C; Step 4: Continue to cool to 90-95°C, add lignin sulfonate, and stir for 20-25 minutes; Step 5: Cool to below 75° C., add β-calcium sulfate hemihydrate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4500-5000 rpm for 30 minutes, grind 1-3 times, and vacuum degas to obtain electric wheel hub bearing grease.

10. The method for preparing electric vehicle hub bearing grease according to claim 9, characterized in that: The following steps are involved: Step 1: Mixing 30% of the base oil by weight with 12-hydroxystearic acid and palmitic acid and stirring uniformly to obtain a mixed solution; Step 2: lithium hydroxide is added with water to prepare a 20 wt% lithium hydroxide aqueous solution, and the mixed solution obtained in step 1 is added to carry out a saponification reaction; the saponification temperature is 105-115° C., and the saponification time is 2-2.5 hours; Step 3: heating to 195-200°C, dehydrating at -0.08-0.05 MPa for 1-1.5 hours, and then rapidly cooling to below 150°C; Step 4: Continue to cool to 90-95°C, add lignin sulfonate and phenyl salicylate, and stir for 20-25 minutes; Step 5: Cool to below 75° C., add β-calcium sulfate hemihydrate whiskers, molten beeswax, extreme pressure anti-wear agent and rust inhibitor, homogenize at 4500-5000 rpm for 30 minutes, grind 1-3 times, and vacuum degas to obtain electric wheel hub bearing grease.

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