Polymer sliding bearing and preparation method thereof

Abstract

The invention belongs to the technical field of sliding bearing manufacturing, and particularly relates to a macromolecule sliding bearing and a preparation method thereof.The preparation method comprises the following steps that a groove is machined in an inner shaft, the groove is filled with an anchoring material, heating and cooling are conducted, an anchoring layer is formed in the groove, the pretreated inner shaft is obtained, a wear-resistant material is pressed on the pretreated inner shaft, and the macromolecule sliding bearing is obtained. Heating treatment and cooling are conducted, when the inner shaft is cooled to the preset temperature, the inner shaft is put into lubricating oil at the same temperature, cooling continues, a low-friction layer is formed on the surface of the inner shaft, and a modified inner shaft is obtained; and assembling the modified inner shaft in the outer shaft to obtain the polymer sliding bearing. According to the sliding bearing, the bonding strength between the inner shaft and the low-friction layer can be improved, and the long-term stability of the sliding bearing under the dynamic load condition is improved.

Description

Technical Field

[0001] This invention belongs to the field of sliding bearing manufacturing technology, and particularly relates to a polymer sliding bearing and its preparation method. Background Technology

[0002] Sliding bearings have high load-bearing capacity, smooth operation, and low noise, and are commonly used in heavy-duty, high-speed, and high-precision environments. To improve the service life of sliding bearings, it is necessary to reduce the coefficient of friction between the bearing bush and the shaft diameter. Current technology typically involves spraying bronze alloy powder onto the inner shaft and sintering it at 800-950℃ to form a porous surface layer attached to the inner shaft. After filling the pores of this porous surface layer with lubricating oil, a low-friction layer is coated on top. This low-friction layer, in its liquid state, penetrates into the micropores of the porous surface layer and, after curing, adheres to the porous surface layer. While this process can reduce the friction between the sliding bearing and the shaft diameter, the porous bronze layer, attached to the inner shaft through spraying and sintering, relies primarily on a limited metallurgical bond, resulting in weak bonding strength. Once the porous layer detaches, the low-friction layer on top also fails, affecting the bearing's lifespan.

[0003] Chinese patent application CN116950998A discloses a sliding bearing bush, manufacturing method, and application, including an inner shaft and a polymer low-friction layer attached to the inner shaft. The inner shaft has a groove, and the polymer low-friction layer is embedded in the groove to fix the polymer low-friction layer and the inner shaft. This patent application avoids the traditional method of relying on a sintered bronze layer as an intermediate layer, which increases the contact area between the low-friction layer and the inner shaft. However, the bonding strength between the low-friction layer and the groove of the inner shaft is low. Under dynamic load conditions, the interface is prone to relative slippage due to stress concentration, which leads to delamination or peeling between the low-friction layer and the inner shaft, affecting the stability of the sliding bearing. Summary of the Invention

[0004] This invention provides a polymer sliding bearing and its preparation method, which improves the bonding strength between the inner shaft and the low-friction layer, and enhances the long-term stability of the sliding bearing under dynamic load conditions.

[0005] To solve the above problems, the present invention adopts the following technical solution: A method for preparing a polymer sliding bearing includes the following steps: S1. A groove is machined on the inner shaft, and anchoring material is filled into the groove. The material is heated and cooled to form an anchoring layer in the groove, thus completing the pretreatment of the inner shaft. The anchoring material is prepared by mixing VTES-modified expanded graphite, divinylbenzene, polyethylene glycol-400, TEOS hydrolysate, VTES hydrolysate, and initiator, and then concentrating under reduced pressure to obtain the anchoring material. S2. Press wear-resistant material onto the pre-treated inner shaft, heat it, cool it, and when it cools to a predetermined temperature, immerse it in lubricating oil at the same temperature and continue cooling to form a low-friction layer on the surface of the inner shaft, thus obtaining a modified inner shaft; the wear-resistant material is prepared by mixing polyphenylene sulfide, molybdenum disulfide, polytetrafluoroethylene, carbon fiber, and antioxidant. S3. Assemble the modified inner shaft into the outer shaft to obtain a polymer sliding bearing.

[0006] This invention first involves machining grooves on the inner shaft. Since the main component of the inner shaft is iron, iron reacts with oxygen in the air to form hydrophilic iron oxides. These iron oxides then undergo hydrolysis with moisture in the air, forming hydroxyl groups on the groove surface. The anchoring material contains silanols produced by the hydrolysis of TEOS and VTES. When the anchoring material is filled into the grooves, the silanols and hydroxyl groups on the groove surface undergo a condensation reaction to form Si-O-metal covalent bonds. The silanols are then grafted onto the groove surface via covalent bonds, and a condensation reaction occurs between the silanols to form a silicon-oxygen network. Under the thermal initiation of an initiator, the silanols produced by the hydrolysis of VTES react with divinylbenzene to form an organic cross-linked network. The silicon-oxygen network and the organic cross-linked network synergistically form a polyethylene glycol-embedded structure. A solid skeleton of polyethylene glycol-400 is heated, and the polyethylene glycol-400 is removed from the solid skeleton, leaving micropores on the solid skeleton to obtain an anchoring layer. The anchoring layer and the groove surface are connected by Si-O-metal covalent bonds, resulting in strong interfacial bonding. After the wear-resistant material comes into contact with the anchoring layer and is heated, the polyphenylene sulfide in the wear-resistant material melts and its viscosity decreases, allowing it to fully penetrate into the micropores. After cooling, the wear-resistant material forms a low-friction layer on the inner shaft. The low-friction layer and the anchoring layer achieve a high-strength connection through mechanical interlocking. The anchoring layer and the inner shaft groove are connected by covalent bonds, resulting in strong bonding between the low-friction layer and the inner shaft. When the sliding bearing is subjected to dynamic loads, the low-friction layer is less likely to peel off from the inner shaft, thus improving the service life of the sliding bearing.

[0007] VTES modification inhibits the agglomeration of expanded graphite and improves its dispersibility in wear-resistant materials. The VTES-modified expanded graphite is located in the groove, so the stress on the VTES-modified expanded graphite is small when the sliding bearing bears dynamic load, thus preventing the VTES-modified expanded graphite from breaking.

[0008] During the process of constructing a low-friction layer on the inner shaft surface, the inner shaft is immersed in lubricating oil. Due to the abundance of micro- and nano-pores in VTES-modified expanded graphite, the lubricating oil is adsorbed and enriched in the VTES-modified expanded graphite under the action of capillary adsorption effect, thus storing the lubricating oil. In subsequent use, VTES-modified expanded graphite continuously releases the lubricating oil to the surface of the low-friction layer, reducing the coefficient of friction between the inner and outer shafts and improving the long-term stability of the sliding bearing.

[0009] Furthermore, the TEOS hydrolysate is prepared by mixing TEOS, 15wt% hydrochloric acid solution, and anhydrous ethanol, adding deionized water while continuously stirring, and stirring at 300 rpm for 1.5 h to obtain the TEOS hydrolysate; the VTES hydrolysate is prepared by mixing VTES, 15wt% hydrochloric acid solution, and anhydrous ethanol, adding deionized water while continuously stirring, and stirring at 300 rpm for 2 h to obtain the VTES hydrolysate.

[0010] The hydroxyl groups on the surface of expanded graphite undergo a condensation reaction with the silanols produced by the hydrolysis of VTES, introducing vinyl functional groups and silanols onto the surface of expanded graphite, resulting in VTES-modified expanded graphite. This allows VTES-modified expanded graphite to participate in the construction of organic cross-linking networks and silicon-oxygen networks, effectively confining the expanded graphite in the anchoring layer. The anchoring layer provides support for the expanded graphite, effectively dispersing stress and preventing the expanded graphite from breaking during the dynamic load process of the sliding bearing.

[0011] Furthermore, the VTES-modified expanded graphite is prepared by adding expanded graphite to VTES hydrolysate, stirring and reacting, and then washing with anhydrous ethanol to obtain VTES-modified expanded graphite.

[0012] Furthermore, in the preparation process of the anchoring material, VTES modified expanded graphite, divinylbenzene, polyethylene glycol-400, TEOS hydrolysate, VTES hydrolysate, and initiator are mixed, stirred at 300 rpm for 30 min, and placed in an environment of 40℃ and 10.1 kPa for stirring at 350 rpm for 3 h to obtain the anchoring material.

[0013] Stirring at 40℃ and 10.1kPa for 3 hours removes most of the ethanol introduced into the system due to the addition of TEOS hydrolysate and VTES hydrolysate, concentrates the anchoring material, increases its viscosity, and makes it less prone to sagging after filling the groove with the anchoring material.

[0014] Furthermore, in step S1, one or more of the following methods are used to fill the groove with anchoring material: molding, injection molding, 3D printing, and prepreg wrapping.

[0015] Furthermore, in step S1, after filling the groove with anchoring material, the inner shaft is placed in an environment of 50°C and kept at that temperature for 1 hour, then heated to 70°C and kept at that temperature for 2 hours, then heated to 120°C and kept at that temperature for 1 hour, then heated to 220°C and kept at that temperature for 1 hour, then heated to 270°C and kept at that temperature for 1 hour, and finally cooled to room temperature, forming an anchoring layer in the groove, thus completing the pretreatment of the inner shaft; the groove is one of annular dovetail groove, dovetail threaded groove, rectangular threaded groove, or T-shaped threaded groove.

[0016] First, the inner shaft is placed in a 50°C environment and kept at that temperature for 1 hour to promote the condensation reaction between silanol and the hydroxyl groups on the groove surface, as well as the condensation reaction between silanols themselves, forming a silicon-oxygen network covalently bonded to the groove. At the same time, vinyl functional groups are introduced onto the groove surface. The temperature is then raised to 70°C and kept at that temperature for 2 hours. Under the initiation of the initiator, the vinyl functional groups on the groove surface and divinylbenzene undergo a copolymerization and crosslinking reaction, forming an organic crosslinking network that interpenetrates the silicon-oxygen network and is covalently bonded to the groove surface. The temperature is then raised to 120°C and kept at that temperature for 1 hour, softening polyethylene glycol-400 and preparing it for subsequent high-temperature migration. The temperature is then raised to 220°C and kept at that temperature for 1 hour, further reducing the viscosity of polyethylene glycol-400 and initiating its outward migration. The temperature is then raised to 270°C and kept at that temperature for 1 hour, causing polyethylene glycol-400 to be expelled from the solid skeleton. The space it occupies forms micropores, thus obtaining an anchoring layer with a porous structure that is covalently bonded to the groove.

[0017] Furthermore, before filling the groove with anchoring material, a 2wt% hydrochloric acid solution is sprayed into the groove, and after 2 minutes, the groove is cleaned with deionized water. The inner shaft is then placed in a 50°C airflow to dry for 10 minutes.

[0018] The groove surface is treated with hydrochloric acid solution and deionized water, and then the groove surface is dried with airflow to increase the density and reactivity of hydroxyl groups on the groove surface, improve the grafting efficiency of silanol, and improve the interfacial bonding force between the anchoring layer and the groove surface.

[0019] Furthermore, in step S2, the wear-resistant material is pressed onto the pretreated inner shaft, heated to 350°C and kept at that temperature for 3 hours, and then naturally cooled to 100°C before being placed in lubricating oil at 100°C. After naturally cooling to room temperature, the shaft is removed, and a low-friction layer is formed on the surface of the inner shaft to obtain the modified inner shaft.

[0020] The inner shaft, cooled to 100°C, is placed in lubricating oil at 100°C and allowed to cool naturally. Since the inner shaft and the lubricating oil are at similar temperatures, the anchoring layer and wear-resistant layer are prevented from cracking due to excessive temperature difference. At the same time, the lubricating oil at 100°C has a lower viscosity and stronger fluidity, which is conducive to the lubricating oil penetrating the wear-resistant layer and anchoring layer and coming into contact with the expanded graphite.

[0021] A polymer sliding bearing includes an outer shaft and a modified inner shaft assembled within the outer shaft; the modified inner shaft includes an inner shaft, an anchoring layer, and a low-friction layer; the anchoring layer comprises the following raw materials in parts by weight: 9-12 parts expanded graphite, 13-18 parts divinylbenzene, 6-8 parts polyethylene glycol-400, 18-24 parts TEOS hydrolysate, 18-24 parts VTES hydrolysate, and 0.8-1.5 parts initiator; the low-friction layer comprises the following raw materials in parts by weight: 50-70 parts polyphenylene sulfide, 10-15 parts molybdenum disulfide, 7-10 parts polytetrafluoroethylene, 7-12 parts carbon fiber, and 0.2-0.6 parts antioxidant; the initiator is AIBN, and the antioxidant is BHT.

[0022] Furthermore, the TEOS hydrolysate comprises the following raw materials in parts by weight: 8-10 parts TEOS, 0.4-0.7 parts 15wt% hydrochloric acid solution, 130-160 parts anhydrous ethanol, and 3-4.5 parts deionized water; the VTES hydrolysate comprises the following raw materials in parts by weight: 17-26 parts VTES, 0.4-0.6 parts 15wt% hydrochloric acid solution, 180-230 parts anhydrous ethanol, and 7-8.5 parts deionized water.

[0023] The beneficial effects of this invention are: This invention prepares a modified inner shaft by creating grooves on the inner shaft, filling the grooves with an anchoring layer, and constructing a low-friction layer on the surface of the inner shaft. The modified inner shaft is then assembled onto an outer shaft to obtain a sliding bearing suitable for use under dynamic load conditions. During the preparation of the modified inner shaft, the anchoring layer and the groove are connected by covalent bonds formed between the silanol produced by the hydrolysis of TEOS and VTES and the metallic hydroxyl groups on the groove surface. The anchoring layer contains micropores created after the removal of polyethylene glycol-400. Polyphenylene sulfide from the wear-resistant material melts and enters these micropores. After cooling, a low-friction layer is obtained, mechanically interlocked with the anchoring layer. The strong bonding force between the low-friction layer and the inner shaft prevents peeling during use under dynamic load conditions, thus improving the service life of the sliding bearing.

[0024] This invention introduces VTES-modified expanded graphite into the anchoring layer. The VTES-modified expanded graphite is located within the groove and confined within the anchoring layer, making it less prone to breakage. During the construction of the low-friction layer, the inner shaft is immersed in lubricating oil, which is enriched in the expanded graphite and continuously released to the surface of the low-friction layer during subsequent use, reducing the coefficient of friction between the inner and outer shafts and improving the long-term stability of the sliding bearing. Detailed Implementation

[0025] Example 1 10g of TEOS (tetraethyl orthosilicate) and 0.5g of 15wt% hydrochloric acid solution were added to 150g of anhydrous ethanol. 3.5g of deionized water was added at a rate of 0.5g / min under stirring at 300rpm for 1.5h to obtain a TEOS hydrolysate. 20g of VTES (vinyltriethoxysilane) and 0.4g of 15wt% hydrochloric acid solution were added to 200g of anhydrous ethanol. 7.5g of deionized water was added at a rate of 0.5g / min under stirring at 300rpm for 2h to obtain a VTES hydrolysate. 10g of expanded graphite was added to 200g of VTES hydrolysate, the mixture was heated to 50℃, stirred at 300rpm for 2h, filtered, and washed with anhydrous ethanol to obtain VTES-modified expanded graphite. VTES-modified expanded graphite was then mixed with 15g of divinylbenzene, 6g of polyethylene glycol-400, 20g of TEOS hydrolysate, and 20g of... VTES hydrolysate and 1g AIBN (azobisisobutyronitrile) were mixed and stirred at 300rpm for 30min. The mixture was then placed in an environment of 40℃ and 10.1kPa and stirred at 350rpm for 3h to obtain the anchoring material. 60g polyphenylene sulfide, 12g molybdenum disulfide, 8g polytetrafluoroethylene, 8g carbon fiber, and 0.3g BHT (2,6-di-tert-butyl-p-cresol) were mixed and stirred at 300rpm for 10min to obtain the wear-resistant material.

[0026] Grooves are machined into the inner shaft, with dovetail-shaped threaded grooves. A 2wt% hydrochloric acid solution is sprayed into the grooves at a rate of 0.1 g / cm², left to stand for 2 minutes, and then washed with deionized water. The inner shaft is then dried in a 50°C airflow for 10 minutes. Anchoring material is then filled into the grooves using a molding method: the inner shaft is placed in a mold, and the anchoring material is extruded into the mold using an extruder. The pressure provided by a press fills the grooves with the anchoring material. The inner shaft is then placed in an oven preheated to 50°C and held for 1 hour. The temperature is then increased to 70°C at a rate of 20°C / hour and held for 2 hours. The temperature is then increased to 120°C at a rate of 20°C / hour and held for 1 hour. Finally, the temperature is increased to 40°C and held for 1 hour. The temperature is increased to 220℃ at a rate of ℃ / h and held for 1 hour. Then, the temperature is increased to 270℃ at a rate of 15℃ / h and held for 1 hour. The shaft is then allowed to cool naturally to room temperature, forming an anchoring layer in the groove, thus completing the pretreatment of the inner shaft. The pretreated inner shaft is then placed in a mold, and the wear-resistant material is extruded into the mold using an extruder. The wear-resistant material is pressed onto the pretreated inner shaft by the pressure provided by a press. The shaft is then heated to 350℃ and held for 3 hours. When it cools naturally to 100℃, it is placed in lubricating oil at 100℃ and allowed to cool naturally to room temperature. The shaft is then removed, and a low-friction layer is formed on the surface of the inner shaft, resulting in a modified inner shaft. The modified inner shaft is then assembled into an outer shaft to obtain a polymer sliding bearing.

[0027] Example 2 8 g of TEOS and 0.7 g of 15 wt% hydrochloric acid solution were added to 160 g of anhydrous ethanol. 3 g of deionized water was added at a rate of 0.5 g / min under stirring at 300 rpm for 1.5 h to obtain a TEOS hydrolysate. 25 g of VTES and 0.5 g of 15 wt% hydrochloric acid solution were added to 230 g of anhydrous ethanol. 8.5 g of deionized water was added at a rate of 0.5 g / min under stirring at 300 rpm for 2 h to obtain a VTES hydrolysate. 9 g of expanded graphite was added to 240 g of VTES hydrolysate, heated to 50 °C, stirred at 300 rpm for 2 h, filtered, and washed with anhydrous ethanol to obtain VTES-modified expanded graphite. VTES-modified expanded graphite was then mixed with 13 g of divinylbenzene, 7 g of polyethylene glycol-400, 19 g of TEOS hydrolysate, 22 g of VTES hydrolysate, and 0.9 g of... Mix AIBN, stir at 300 rpm for 30 min, place in an environment of 40℃ and 10.1 kPa, and stir at 350 rpm for 3 h to obtain the anchoring material; mix 70 g of polyphenylene sulfide, 11 g of molybdenum disulfide, 8 g of polytetrafluoroethylene, 9 g of carbon fiber and 0.6 g of BHT, and stir at 300 rpm for 10 min to obtain the wear-resistant material.

[0028] A groove, an annular dovetail groove, is machined on the inner shaft. A 2wt% hydrochloric acid solution is sprayed into the groove at a rate of 0.1 g / cm², allowed to stand for 2 minutes, and then the groove is washed with deionized water. The inner shaft is then dried in a 50°C airflow for 10 minutes. Next, the anchoring material is filled into the groove using injection molding: the inner shaft is placed into the mold cavity and the mold is closed. The anchoring material is injected into the mold cavity using an injection molding machine, filling the groove. After setting, the mold is opened, the inner shaft is removed, and placed in an oven preheated to 50°C for 1 hour. The temperature is then increased to 70°C at a rate of 20°C / hour and held for 2 hours. Finally, the temperature is increased to 120°C at a rate of 20°C / hour and held for 1 hour. The inner shaft is pre-treated by heating to 220°C at a rate of 40°C / h and holding for 1 hour, then heating to 270°C at a rate of 15°C / h and holding for 1 hour, followed by natural cooling to room temperature. An anchoring layer is formed in the groove. The pre-treated inner shaft is then placed in a mold, and wear-resistant material is extruded into the mold using an extruder. The wear-resistant material is pressed onto the pre-treated inner shaft by pressure provided by a press. The shaft is then heated to 350°C and held for 3 hours. After natural cooling to 100°C, it is placed in lubricating oil at 100°C and allowed to cool to room temperature. The shaft is then removed, and a low-friction layer is formed on the surface of the inner shaft, resulting in a modified inner shaft. The modified inner shaft is then assembled into an outer shaft to obtain a polymer sliding bearing.

[0029] Example 3 9 g of TEOS and 0.4 g of 15 wt% hydrochloric acid solution were added to 130 g of anhydrous ethanol. 4.5 g of deionized water was added at a rate of 0.5 g / min under stirring at 300 rpm for 1.5 h to obtain a TEOS hydrolysate. 23 g of VTES and 0.6 g of 15 wt% hydrochloric acid solution were added to 180 g of anhydrous ethanol. 8.5 g of deionized water was added at a rate of 0.5 g / min under stirring at 300 rpm for 2 h to obtain a VTES hydrolysate. 10 g of expanded graphite was added to 180 g of VTES hydrolysate, the mixture was heated to 50 °C, stirred at 300 rpm for 2 h, filtered, and washed with anhydrous ethanol to obtain VTES-modified expanded graphite. The VTES-modified expanded graphite was then mixed with 16 g of divinylbenzene, 8 g of polyethylene glycol-400, 24 g of TEOS hydrolysate, 18 g of VTES hydrolysate, and 0.8 g of... Mix AIBN, stir at 300 rpm for 30 min, place in an environment of 40℃ and 10.1 kPa, and stir at 350 rpm for 3 h to obtain the anchoring material; mix 50 g of polyphenylene sulfide, 12 g of molybdenum disulfide, 7 g of polytetrafluoroethylene, 12 g of carbon fiber and 0.5 g of BHT, and stir at 300 rpm for 10 min to obtain the wear-resistant material.

[0030] A rectangular threaded groove is machined into the inner shaft. A 2wt% hydrochloric acid solution is sprayed into the groove at a rate of 0.1 g / cm², left to stand for 2 minutes, and then washed with deionized water. The inner shaft is then dried in a 50°C airflow for 10 minutes. Anchoring material is then filled into the groove using 3D printing: the inner shaft is mounted on the 3D printer's fixture, which rotates the inner shaft around its axis. Anchoring material is filled into the groove through a nozzle. The inner shaft is then placed in an oven preheated to 50°C and held for 1 hour. The temperature is then increased to 70°C at a rate of 20°C / hour and held for 2 hours. The temperature is then increased to 120°C at a rate of 20°C / hour and held for 1 hour. Finally, the temperature is increased to 40°C... The temperature is increased to 220℃ at a rate of 15℃ / h and held for 1 hour. Then, the temperature is increased to 270℃ at a rate of 15℃ / h and held for 1 hour. The shaft is then allowed to cool naturally to room temperature, forming an anchoring layer in the groove, thus completing the pretreatment of the inner shaft. The pretreated inner shaft is then placed in a mold, and the wear-resistant material is extruded into the mold using an extruder. The wear-resistant material is pressed onto the pretreated inner shaft by the pressure provided by a press. The shaft is then heated to 350℃ and held for 3 hours. When it cools naturally to 100℃, it is placed in lubricating oil at 100℃ and allowed to cool naturally to room temperature. The shaft is then removed, and a low-friction layer is formed on the surface of the inner shaft, resulting in a modified inner shaft. The modified inner shaft is then assembled into an outer shaft to obtain a polymer sliding bearing.

[0031] Example 4 9g TEOS and 0.6g 15wt% hydrochloric acid solution were added to 140g anhydrous ethanol. 3g deionized water was added at a rate of 0.5g / min under stirring at 300rpm for 1.5h to obtain TEOS hydrolysate. 17g VTES and 0.5g 15wt% hydrochloric acid solution were added to 200g anhydrous ethanol. 8g deionized water was added at a rate of 0.5g / min under stirring at 300rpm for 2h to obtain VTES hydrolysate. 11g expanded graphite was added to 180g VTES hydrolysate, heated to 50℃, stirred at 300rpm for 2h, filtered, and washed with anhydrous ethanol to obtain VTES-modified expanded graphite. VTES-modified expanded graphite was then mixed with 18g divinylbenzene, 8g polyethylene glycol-400, 23g TEOS hydrolysate, 22g VTES hydrolysate, and 1g... Mix AIBN, stir at 300 rpm for 30 min, place in an environment of 40℃ and 10.1 kPa, and stir at 350 rpm for 3 h to obtain the anchoring material; mix 55 g of polyphenylene sulfide, 10 g of molybdenum disulfide, 9 g of polytetrafluoroethylene, 10 g of carbon fiber and 0.4 g of BHT, and stir at 300 rpm for 10 min to obtain the wear-resistant material.

[0032] A groove, an annular dovetail groove, is machined on the inner shaft. A 2wt% hydrochloric acid solution is sprayed into the groove at a rate of 0.1 g / cm², left to stand for 2 minutes, and then washed with deionized water. The inner shaft is then dried in a 50°C airflow for 10 minutes. Anchoring material is then filled into the groove using 3D printing: the inner shaft is mounted on the 3D printer's fixture, which rotates the inner shaft around its axis. Anchoring material is filled into the groove through a nozzle. The inner shaft is then placed in an oven preheated to 50°C and held for 1 hour. The temperature is then increased to 70°C at a rate of 20°C / hour and held for 2 hours. The temperature is then increased to 120°C at a rate of 20°C / hour and held for 1 hour. Finally, the temperature is increased to 40°C... The temperature is increased to 220℃ at a rate of 15℃ / h and held for 1 hour. Then, the temperature is increased to 270℃ at a rate of 15℃ / h and held for 1 hour. The shaft is then allowed to cool naturally to room temperature, forming an anchoring layer in the groove, thus completing the pretreatment of the inner shaft. The pretreated inner shaft is then placed in a mold, and the wear-resistant material is extruded into the mold using an extruder. The wear-resistant material is pressed onto the pretreated inner shaft by the pressure provided by a press. The shaft is then heated to 350℃ and held for 3 hours. When it cools naturally to 100℃, it is placed in lubricating oil at 100℃ and allowed to cool naturally to room temperature. The shaft is then removed, and a low-friction layer is formed on the surface of the inner shaft, resulting in a modified inner shaft. The modified inner shaft is then assembled into an outer shaft to obtain a polymer sliding bearing.

[0033] Example 5 10g TEOS and 0.7g 15wt% hydrochloric acid solution were added to 150g anhydrous ethanol. 4g deionized water was added at a rate of 0.5g / min under stirring at 300rpm for 1.5h to obtain TEOS hydrolysate. 26g VTES and 0.5g 15wt% hydrochloric acid solution were added to 210g anhydrous ethanol. 7g deionized water was added at a rate of 0.5g / min under stirring at 300rpm for 2h to obtain VTES hydrolysate. 12g expanded graphite was added to 220g VTES hydrolysate, heated to 50℃, stirred at 300rpm for 2h, filtered, and washed with anhydrous ethanol to obtain VTES-modified expanded graphite. VTES-modified expanded graphite was then mixed with 14g divinylbenzene, 7g polyethylene glycol-400, 20g TEOS hydrolysate, 24g VTES hydrolysate, and 1.5g... Mix AIBN, stir at 300 rpm for 30 min, place in an environment of 40℃ and 10.1 kPa, and stir at 350 rpm for 3 h to obtain the anchoring material; mix 65 g of polyphenylene sulfide, 14 g of molybdenum disulfide, 10 g of polytetrafluoroethylene, 7 g of carbon fiber and 0.3 g of BHT, and stir at 300 rpm for 10 min to obtain the wear-resistant material.

[0034] A groove, a T-shaped threaded groove, is machined on the inner shaft. A 2wt% hydrochloric acid solution is sprayed into the groove at a rate of 0.1 g / cm², left to stand for 2 minutes, and then washed with deionized water. The inner shaft is then dried in a 50°C airflow for 10 minutes. The anchoring material is then filled into the groove using a prepreg tape wrapping method: 20 g of fiber (including but not limited to carbon fiber, glass fiber, and aramid fiber) is added to the anchoring material and soaked for 5 hours to prepare a prepreg tape. The prepreg tape is then wrapped around the inner shaft through a nozzle, allowing the anchoring material to enter the groove. The inner shaft is then placed in an oven preheated to 50°C and kept at that temperature for 1 hour. The temperature is then increased to 70°C at a rate of 20°C / hour and kept at that temperature for 2 hours, followed by another increase at a rate of 20°C / hour. The temperature is raised to 120℃ and held for 1 hour. Then, the temperature is increased to 220℃ at a rate of 40℃ / h and held for 1 hour. Finally, the temperature is increased to 270℃ at a rate of 15℃ / h and held for 1 hour. The material is then allowed to cool naturally to room temperature, forming an anchoring layer in the groove, thus completing the pretreatment of the inner shaft. The pretreated inner shaft is then placed in a mold, and the wear-resistant material is extruded into the mold using an extruder. The wear-resistant material is pressed onto the pretreated inner shaft by the pressure provided by a press. The temperature is raised to 350℃ and held for 3 hours. When the temperature is allowed to cool naturally to 100℃, the shaft is placed in lubricating oil at 100℃ and allowed to cool naturally to room temperature. The shaft is then removed, and a low-friction layer is formed on the surface of the inner shaft, resulting in a modified inner shaft. The modified inner shaft is then assembled into an outer shaft to obtain a polymer sliding bearing.

[0035] Example 6 8 g of TEOS and 0.5 g of 15 wt% hydrochloric acid solution were added to 160 g of anhydrous ethanol. 3.5 g of deionized water was added at a rate of 0.5 g / min under stirring at 300 rpm for 1.5 h to obtain a TEOS hydrolysate. 20 g of VTES and 0.6 g of 15 wt% hydrochloric acid solution were added to 220 g of anhydrous ethanol. 8 g of deionized water was added at a rate of 0.5 g / min under stirring at 300 rpm for 2 h to obtain a VTES hydrolysate. 9 g of expanded graphite was added to 200 g of VTES hydrolysate, heated to 50 °C, stirred at 300 rpm for 2 h, filtered, and washed with anhydrous ethanol to obtain VTES-modified expanded graphite. VTES-modified expanded graphite was then mixed with 13 g of divinylbenzene, 6 g of polyethylene glycol-400, 18 g of TEOS hydrolysate, 24 g of VTES hydrolysate, and 1 g of... Mix AIBN, stir at 300 rpm for 30 min, place in an environment of 40℃ and 10.1 kPa, and stir at 350 rpm for 3 h to obtain the anchoring material; mix 60 g of polyphenylene sulfide, 15 g of molybdenum disulfide, 10 g of polytetrafluoroethylene, 10 g of carbon fiber and 0.2 g of BHT, and stir at 300 rpm for 10 min to obtain the wear-resistant material.

[0036] A groove, a T-shaped threaded groove, is machined on the inner shaft. A 2wt% hydrochloric acid solution is sprayed into the groove at a rate of 0.1 g / cm², left to stand for 2 minutes, and then washed with deionized water. The inner shaft is then dried in a 50°C airflow for 10 minutes. The anchoring material is then filled into the groove using a prepreg tape wrapping method: 20 g of fiber (including but not limited to carbon fiber, glass fiber, and aramid fiber) is added to the anchoring material and soaked for 5 hours to prepare a prepreg tape. The prepreg tape is then wrapped around the inner shaft through a nozzle, allowing the anchoring material to enter the groove. The inner shaft is then placed in an oven preheated to 50°C and kept at that temperature for 1 hour. The temperature is then increased to 70°C at a rate of 20°C / hour and kept at that temperature for 2 hours, followed by another increase at a rate of 20°C / hour. The temperature is raised to 120℃ and held for 1 hour. Then, the temperature is increased to 220℃ at a rate of 40℃ / h and held for 1 hour. Finally, the temperature is increased to 270℃ at a rate of 15℃ / h and held for 1 hour. The material is then allowed to cool naturally to room temperature, forming an anchoring layer in the groove, thus completing the pretreatment of the inner shaft. The pretreated inner shaft is then placed in a mold, and the wear-resistant material is extruded into the mold using an extruder. The wear-resistant material is pressed onto the pretreated inner shaft by the pressure provided by a press. The temperature is raised to 350℃ and held for 3 hours. When the temperature is allowed to cool naturally to 100℃, the shaft is placed in lubricating oil at 100℃ and allowed to cool naturally to room temperature. The shaft is then removed, and a low-friction layer is formed on the surface of the inner shaft, resulting in a modified inner shaft. The modified inner shaft is then assembled into an outer shaft to obtain a polymer sliding bearing.

[0037] The present invention also includes comparative examples and related experiments.

[0038] Comparative Example 1 The difference between this comparative example and Example 6 is that no VTES hydrolysate and TEOS hydrolysate were added during the preparation of the anchoring material. The other operating steps and conditions were the same as in Example 6, resulting in a modified inner shaft and sliding bearing.

[0039] Comparative Example 2 The difference between this comparative example and Example 6 is that polyethylene glycol-400 was not added during the preparation of the anchoring material. The other operating steps and conditions were the same as in Example 6, resulting in a modified inner shaft and a sliding bearing.

[0040] Comparative Example 3 The difference between this comparative example and Example 6 is that VTES-modified expanded graphite was not added during the preparation of the anchoring material. Other operating steps and conditions were the same as in Example 6, resulting in a modified inner shaft and sliding bearing.

[0041] Peel resistance test Using a micron scratch tester equipped with a diamond indenter, scratch tests were performed on the low-friction layers on the modified inner shafts prepared in each embodiment and each comparative example. The initial peel load of the low-friction layers was measured, as shown in Table 1.

[0042] Table 1

[0043] As shown in Table 1, the initial peel load of the low-friction layer on the surface of the modified inner shaft prepared in Examples 1 to 6 and Comparative Example 3 is relatively large, indicating that the bonding strength between the low-friction layer connected to the inner shaft by the anchoring material is large and it is not easy to peel off from the inner shaft. The initial peel load of the low-friction layer on the surface of the modified inner shaft prepared in Example 6 is greater than that in Comparative Example 1 and Comparative Example 2, indicating that the addition of VTES hydrolysate, TEOS hydrolysate, and polyethylene glycol-400 during the preparation of the anchoring material can improve the interfacial bonding strength between the anchoring material and the inner shaft, and between the anchoring material and the low-friction layer, thereby improving the bonding strength between the low-friction layer and the inner shaft.

[0044] Friction coefficient test The sliding bearings manufactured in each embodiment and comparative example were assembled on a rotary friction testing machine. The load was set to vary sinusoidally between 1000N and 3000N, with a frequency of 0.1Hz and a rotational speed of 20rpm. The machine was continuously run for 50,000 revolutions under dry friction conditions. Torque was collected in real time during the operation, and the torque was calculated according to the formula:

[0045] The friction coefficients between the inner and outer shafts of each sliding bearing were calculated at 5000 rpm, 10000 rpm, and 50000 rpm. The results are shown in Table 2.

[0046] Table 2

[0047] As shown in Table 2, the friction coefficient of the sliding bearings prepared in Examples 1 to 6 after running for 50,000 revolutions is lower than that of Comparative Examples 1 to 3. This indicates that under long-term dynamic load conditions, the low-friction layer in the sliding bearing prepared in this invention is not easy to peel off, and the lubricating oil stored in the expanded graphite can be continuously released between the low-friction layer and the outer shaft. The inner shaft and the outer shaft can maintain a low friction coefficient for a longer period of time, thereby improving the service life of the sliding bearing under dynamic load conditions.

Claims

1. A method for preparing a polymer sliding bearing, characterized in that, Includes the following steps: S1. A groove is machined on the inner shaft, and anchoring material is filled into the groove. The material is heated and cooled to form an anchoring layer in the groove, thus completing the pretreatment of the inner shaft. The anchoring material is prepared by mixing VTES-modified expanded graphite, divinylbenzene, polyethylene glycol-400, TEOS hydrolysate, VTES hydrolysate, and initiator, and then concentrating under reduced pressure to obtain the anchoring material. S2. Press wear-resistant material onto the pre-treated inner shaft, heat it, cool it, and when it cools to a predetermined temperature, immerse it in lubricating oil at the same temperature and continue cooling to form a low-friction layer on the surface of the inner shaft, thus obtaining a modified inner shaft; the wear-resistant material is prepared by mixing polyphenylene sulfide, molybdenum disulfide, polytetrafluoroethylene, carbon fiber, and antioxidant. S3. Assemble the modified inner shaft into the outer shaft to obtain a polymer sliding bearing.

2. The method for preparing a polymer sliding bearing according to claim 1, characterized in that, The TEOS hydrolysate was prepared by mixing TEOS, 15wt% hydrochloric acid solution, and anhydrous ethanol, adding deionized water while stirring continuously, and stirring at 300 rpm for 1.5 h to obtain the TEOS hydrolysate. The VTES hydrolysate was prepared by mixing VTES, 15wt% hydrochloric acid solution, and anhydrous ethanol, adding deionized water while stirring continuously, and stirring at 300 rpm for 2 h to obtain the VTES hydrolysate.

3. The method for preparing a polymer sliding bearing according to claim 2, characterized in that, The VTES-modified expanded graphite is prepared by adding expanded graphite to VTES hydrolysate, stirring and reacting, and then washing with anhydrous ethanol to obtain VTES-modified expanded graphite.

4. The method for preparing a polymer sliding bearing according to claim 3, characterized in that, In the preparation process of the anchoring material, VTES modified expanded graphite, divinylbenzene, polyethylene glycol-400, TEOS hydrolysate, VTES hydrolysate and initiator are mixed, stirred at 300 rpm for 30 min, and placed in an environment of 40℃ and 10.1 kPa, stirred at 350 rpm for 3 h to obtain the anchoring material.

5. The method for preparing a polymer sliding bearing according to claim 4, characterized in that, In step S1, one or more of the following methods are used to fill the groove with anchoring material: molding, injection molding, 3D printing, and prepreg wrapping.

6. The method for preparing a polymer sliding bearing according to claim 5, characterized in that, In step S1, after filling the groove with anchoring material, the inner shaft is placed in an environment of 50°C and kept at that temperature for 1 hour, then heated to 70°C and kept at that temperature for 2 hours, then heated to 120°C and kept at that temperature for 1 hour, then heated to 220°C and kept at that temperature for 1 hour, then heated to 270°C and kept at that temperature for 1 hour, and finally cooled to room temperature, forming an anchoring layer in the groove, thus completing the pretreatment of the inner shaft; the groove is one of annular dovetail groove, dovetail threaded groove, rectangular threaded groove, or T-shaped threaded groove.

7. The method for preparing a polymer sliding bearing according to claim 6, characterized in that, Before filling the groove with anchoring material, spray a 2wt% hydrochloric acid solution into the groove, clean the groove with deionized water after 2 minutes, and dry the inner shaft in a 50°C airflow for 10 minutes.

8. The method for preparing a polymer sliding bearing according to claim 7, characterized in that, In step S2, the wear-resistant material is pressed onto the pretreated inner shaft, heated to 350°C and kept at that temperature for 3 hours, and then naturally cooled to 100°C before being placed in lubricating oil at 100°C. After naturally cooling to room temperature, the shaft is removed, and a low-friction layer is formed on the surface of the inner shaft, thus obtaining the modified inner shaft.

9. A polymer sliding bearing, characterized in that, The polymer sliding bearing, prepared using the method described in any one of claims 4-8, comprises an outer shaft and a modified inner shaft assembled within the outer shaft. The modified inner shaft includes an inner shaft, an anchoring layer, and a low-friction layer. The anchoring layer comprises the following parts by weight of raw materials: 9-12 parts expanded graphite, 13-18 parts divinylbenzene, 6-8 parts polyethylene glycol-400, 18-24 parts TEOS hydrolysate, 18-24 parts VTES hydrolysate, and 0.8-1.5 parts initiator. The low-friction layer comprises the following parts by weight of raw materials: 50-70 parts polyphenylene sulfide, 10-15 parts molybdenum disulfide, 7-10 parts polytetrafluoroethylene, 7-12 parts carbon fiber, and 0.2-0.6 parts antioxidant. The initiator is AIBN, and the antioxidant is BHT.

10. A polymer sliding bearing according to claim 9, characterized in that, The TEOS hydrolysate comprises the following raw materials in parts by weight: 8-10 parts TEOS, 0.4-0.7 parts 15wt% hydrochloric acid solution, 130-160 parts anhydrous ethanol, and 3-4.5 parts deionized water; the VTES hydrolysate comprises the following raw materials in parts by weight: 17-26 parts VTES, 0.4-0.6 parts 15wt% hydrochloric acid solution, 180-230 parts anhydrous ethanol, and 7-8.5 parts deionized water.

Images