Copper lining inlaid wear-resistant bushing and preparation method thereof

Abstract

The invention provides a copper lining inlaid wear-resistant bushing and a preparation method thereof, and belongs to the field of bushings. The copper lining inlaid wear-resistant bushing comprises a copper lining, hole grooves are formed in the copper lining, and a composite wear-resistant material is inlaid in the hole grooves. The composite wear-resistant material comprises polyamide, polyformaldehyde, nano-graphite, polytetrafluoroethylene powder, molybdenum disulfide, short carbon fibers, a silane coupling agent, an antioxidant and a lubricant. The preparation method comprises the following steps: preparing an annular copper lining, and processing uniformly distributed hole grooves in the working surface of the copper lining; a composite wear-resistant material is mechanically embedded in the hole groove through an injection molding method; and the flat end face, the inner wall and the outer wall of the copper lining are machined and cleaned to obtain the copper lining inlaid wear-resistant bushing. According to the inlaying scheme that the copper lining is combined with the specific composite wear-resistant material, the wear resistance of the material is improved, refueling maintenance is not needed, and the abrasion loss is reduced.

Description

Technical Field

[0001] This invention belongs to the field of bushing technology, and specifically relates to a copper-lined wear-resistant bushing and its preparation method. Background Technology

[0002] A bushing is a ring that acts as a liner. Copper-based bushings (or simply copper bushings) are widely used in metallurgical continuous casting machines, aluminum alloy rolling equipment, mining machinery, new energy vehicles, wind power, and photovoltaics due to their self-lubricating properties, good electrical conductivity, and high-temperature resistance, which allows them to operate stably at 500℃. Although copper has good wear resistance and electrical conductivity, it is expensive, has low hardness, is prone to wear and deformation, and requires frequent lubrication, a process that is not only cumbersome but also causes environmental pollution and incurs high maintenance costs.

[0003] To address these issues, holes or grooves are drilled or milled into the working surface of existing copper bushings, and graphite rods are pressed into or filled into the holes or grooves to create graphite-embedded copper bushings. This improves the wear resistance of the copper bushings and reduces the need for grease lubrication. However, graphite-embedded copper bushings still suffer from defects such as low material hardness and susceptibility to wear and deformation. Furthermore, water exposure can damage the lubricating film formed by the graphite on the friction surface, leading to increased friction and accelerated wear, thus affecting lubrication performance and service life. Under high temperatures, the fixing adhesive is also prone to aging and detachment. Summary of the Invention

[0004] Therefore, the present invention aims to provide a copper-lined wear-resistant bushing and its preparation method, in order to solve at least one technical problem in the background art.

[0005] This invention is implemented as follows: The first aspect of the present invention provides a copper-lined wear-resistant bushing, the copper-lined wear-resistant bushing includes a copper liner, the copper liner having grooves arranged on it, and a composite wear-resistant material being inlaid in the grooves. The composite wear-resistant material comprises the following parts by weight: 60-70 parts of polyamide; 10 to 15 parts of polyoxymethylene; 3 to 5 parts of nano-graphite; 5 to 8 parts of polytetrafluoroethylene powder; 2 to 3 parts of molybdenum disulfide; 5 to 10 parts of chopped carbon fiber; 0.5 to 1 part of silane coupling agent; Antioxidant 0.3 to 0.5 parts; 1 to 2 parts lubricant.

[0006] Preferably, the antioxidant is antioxidant 1010; the lubricant is silicone masterbatch.

[0007] Preferably, the copper liner inlaid with wear-resistant bushing also includes an aluminum outer base, which is fitted over the copper liner and assembled as a whole.

[0008] A second aspect of the present invention provides a method for preparing the above-mentioned copper-lined wear-resistant bushing, the method comprising the following steps: S1, Prepare an annular copper liner, and machine uniformly distributed holes and grooves on the working surface of the copper liner; S2, composite wear-resistant material is mechanically embedded in the grooves by injection molding; S3, the flat end face and inner and outer walls of the copper liner are machined and cleaned to obtain a copper liner inlaid with a wear-resistant bushing.

[0009] Preferably, S1 further includes: preparing an annular aluminum outer base, and then using interference fitting or temperature difference fitting to assemble the aluminum outer base and the copper liner into one piece, with the aluminum outer base fitted over the copper liner; S3 also includes: machining the flat end face and outer wall of the aluminum outer base.

[0010] Preferably, the specific steps of S1 are as follows: S11 uses seamless aluminum alloy tubes as the base material, and after cutting and polishing, it obtains an annular aluminum outer base with an inner hole roughness Ra≤1.6μm; S12, using copper plate as substrate, is processed by punching, rolling, joining and polishing to obtain an annular copper liner with an outer surface roughness Ra≤1.6μm, and the copper liner has uniformly distributed holes and grooves. The end of the groove near the aluminum outer base is flared outwards in the shape of a trumpet.

[0011] Preferably, the specific steps of the injection molding method in S2 are as follows: S21, Weigh the raw materials of the composite wear-resistant material according to the proportion; S22, nano-graphite and polytetrafluoroethylene powder are first dried; short-cut carbon fibers are impregnated with a silane coupling agent solution diluted with ethanol. S23 and S22 dried nano-graphite, polytetrafluoroethylene powder, and short-cut carbon fibers impregnated with silane coupling agent are mixed with polyamide, polyoxymethylene, molybdenum disulfide, antioxidant, and lubricant in a high-speed mixer. S24 uses a twin-screw extruder to melt-blend the mixed raw materials; S25 involves injection molding molten blended raw materials into slots, resulting in the mechanical embedding of composite wear-resistant materials within the slots.

[0012] Preferably, the twin-screw extruder employs segmented temperature control, wherein the temperature of the feeding section is 200℃±5℃, the temperature of the compression section is 230℃±5℃, the temperature of the homogenization section is 220℃±5℃, and the temperature of the die head is 210℃±5℃.

[0013] Preferably, the injection molding conditions include: injection temperature of 230℃~250℃, mold temperature of 80℃~100℃, and holding pressure of 60MPa~80MPa.

[0014] Preferably, the specific steps of S3 are as follows: S31, the aluminum outer base flat end face is chamfered, and the copper liner flat end face is chamfered. S32, using a ball head to evenly distribute dots on the outer wall of the aluminum outer base, applying at least four sets of fixing points; S33, the outer wall of the aluminum base and the inner wall of the copper liner are ground to remove injection molding inlay defects and dotting defects; S34, ultrasonic cleaning and polishing.

[0015] Preferably, the depth of the fixing point is 0.4mm to 0.6mm; During the dotting operation, a solid shaft is used to protect the inner wall of the copper liner.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses a copper liner combined with a specific composite wear-resistant material inlay scheme, which improves the wear resistance of the material and eliminates the need for oiling maintenance, thus reducing wear.

[0017] 2. This invention modifies the embedded graphite material to improve its heat resistance, self-lubrication, and wear resistance, meeting environmental protection requirements while satisfying requirements for interfacial bonding strength, coefficient of friction, and wear rate. Compared with traditional copper sleeves, this invention uses nano-graphite and polytetrafluoroethylene to synergistically reduce the coefficient of friction, and molybdenum disulfide to reduce metal-to-metal contact wear. The polyamide / polyoxymethylene blend matrix can withstand temperatures up to 120℃~150℃, and antioxidants ensure stable performance after repeated heating.

[0018] 3. This invention achieves lightweighting, and compared with the manual die-casting and adhesive bonding of wear-resistant round bars, it not only has a better coating effect and higher bonding strength, but also, due to the use of injection molding and inlay, is more environmentally friendly, temperature-resistant and durable than bonding.

[0019] 4. Compared with traditional inlay techniques, the processing technology developed in this invention, through injection molding, greatly improves molding efficiency.

[0020] 5. The present invention uses a polishing process to roughen the inner hole of the aluminum alloy sleeve and the outer circle of the copper liner, and forms an interference fit; at the same time, the interface bonding strength is strengthened by a dotting method, which solves the problem of insufficient torsional force after the aluminum alloy-copper liner is fitted. Detailed Implementation To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] This invention relates to a copper-lined wear-resistant bushing, which includes an aluminum outer base and a copper liner. The aluminum outer base is fitted over the copper liner and assembled as a whole. The copper liner has holes and grooves, and composite wear-resistant material is inlaid in the holes and grooves.

[0022] In some preferred embodiments, an aluminum outer base is also included, which is fitted over the copper liner and assembled as a whole.

[0023] The composite wear-resistant material comprises the following components by weight: 60-70 parts polyamide; 10-15 parts polyoxymethylene; 3-5 parts nano-graphite; 5-8 parts polytetrafluoroethylene powder; 2-3 parts molybdenum disulfide; 5-10 parts chopped carbon fiber; 0.5-1 part silane coupling agent; 0.3-0.5 parts antioxidant; and 1-2 parts lubricant. The antioxidant used is antioxidant 1010; the lubricant is silicone masterbatch.

[0024] Polyamide and polyoxymethylene are used as matrix materials. Polyamide has properties such as high strength, heat resistance and wear resistance, and is suitable for repeated injection molding. Polyoxymethylene can improve the rigidity and dimensional stability of the material and form a blending and reinforcing effect with polyamide.

[0025] Nano-graphite, polytetrafluoroethylene powder, and molybdenum disulfide are wear-resistant additives. Nano-graphite has high lubricity, conductivity, and high temperature resistance, which can reduce the coefficient of friction. Polytetrafluoroethylene powder can form a lubricating film, reducing dynamic friction and wear, and is suitable for high-load scenarios. Molybdenum disulfide has a strong affinity for metals, improving the wear resistance of the material-metal contact surface.

[0026] Short-cut carbon fibers and silane coupling agents can be used as reinforcing and interface modifiers. In practice, short-cut carbon fibers are impregnated with silane coupling agent solution. Short-cut carbon fibers can improve the overall structural strength of the material and reduce the shrinkage rate. Silane coupling agents can improve the compatibility and dispersibility of fillers such as nano-graphite with the matrix material.

[0027] Antioxidants and lubricants are auxiliary additives. Antioxidants are used to prevent thermal oxidative degradation during repeated heating processes; lubricants are used to improve processing fluidity and reduce wear on injection molding equipment.

[0028] A method for preparing a copper-lined wear-resistant bushing includes steps S1 to S3.

[0029] S1, the preparation of an annular aluminum outer base and copper liner, and the working surface of the copper liner is processed with uniformly distributed holes and grooves; specifically including: using a copper plate as the base material, through punching, rolling, joining and polishing, to obtain an annular copper liner with an outer surface roughness Ra≤1.6μm, and the copper liner is provided with uniformly distributed holes and grooves; the end of the hole and groove near the aluminum outer base is an outwardly flared horn shape.

[0030] In some preferred embodiments, this step further includes: using an aluminum alloy seamless tube as the substrate, cutting and polishing it to obtain an annular aluminum outer base with an inner hole roughness Ra≤1.6μm; using interference fit or temperature difference fit, assembling the aluminum outer base and the copper liner into one piece to form a composite aluminum-copper sleeve with the aluminum outer base fitted over the copper liner.

[0031] S2, a composite wear-resistant material is mechanically embedded in the grooves via injection molding; specifically including: S21, Weigh the raw materials of the composite wear-resistant material according to the proportion; S22, nano-graphite and polytetrafluoroethylene powder are first dried to avoid moisture affecting dispersibility; short-cut carbon fibers are impregnated with a silane coupling agent solution diluted with ethanol to enhance interfacial bonding. Nano-graphite and polytetrafluoroethylene powder after S23 and S22 drying treatment, as well as short-cut carbon fibers after silane coupling agent impregnation treatment, are mixed with polyamide, polyoxymethylene, molybdenum disulfide, antioxidant, and lubricant in a high-speed mixer. The mixing temperature is 80℃~100℃ and the time is about 15 minutes to achieve homogeneous mixing and evaporate ethanol at the same time. S24, a twin-screw extruder is used to melt and blend the mixed raw materials; the twin-screw extruder is internally temperature-controlled in sections, with the temperature of the feeding section being 200℃±5℃, the temperature of the compression section being 230℃±5℃, the temperature of the homogenization section being 220℃±5℃, and the temperature of the die head being 210℃±5℃. S25, the molten blended raw materials are injection molded in the cavity, so that the composite wear-resistant material is mechanically embedded in the cavity; the injection molding conditions include: injection temperature of 230℃~250℃, mold temperature of 80℃~100℃; holding pressure of 60MPa~80MPa.

[0032] S3 involves machining the flat end faces and inner and outer walls of the aluminum outer base and copper liner, followed by cleaning to obtain a copper-lined wear-resistant bushing; specifically including: S31, the inner circle chamfer is made on the flat end face of the copper substrate. In some preferred embodiments, the outer circle chamfer is also made on the flat end face of the aluminum outer substrate. S32, a ball head is used to evenly mark dots on the outer wall of the aluminum outer base, applying at least four sets of fixing points; the depth of the fixing points is 0.4mm~0.6mm; during the dotting operation, a solid shaft is used to protect the inner wall of the copper liner to prevent deformation; S33: The outer wall of the aluminum base and the inner wall of the copper liner are ground to remove injection molding defects and dot defects; to ensure cleanliness, dimensional accuracy, roundness and concentricity, etc. S34, perform ultrasonic cleaning and polishing to maintain product cleanliness.

[0033] Testing revealed that the copper-lined wear-resistant bushing prepared by this invention exhibits a peeling torsional force at the interface between the aluminum outer base and the copper liner ≥3.7 N·m; a friction coefficient ≤0.15; a wear amount ≤0.011 mm; environmental protection requirements comply with GB / T30512-2014 standard; and it shows no red rust after 500 hours of neutral salt spray testing.

[0034] Example 1 A method for preparing a copper-lined wear-resistant bushing includes the following steps S1 to S3.

[0035] S1 uses a copper plate with a thickness of 4mm as the base material. After punching, rolling, joining and polishing, an annular copper liner with an outer surface roughness Ra≤1.6μm is obtained. The copper liner has uniformly distributed holes and grooves (2mm deep); the inner end of the holes and grooves is an outwardly flared horn shape.

[0036] S2, weigh out 60 parts of polyamide (PA66), 15 parts of polyoxymethylene (POM), 3 parts of nano-graphite, 8 parts of polytetrafluoroethylene powder, 2 parts of molybdenum disulfide, 10 parts of chopped carbon fiber, 0.5 parts of silane coupling agent, 0.5 parts of antioxidant 1010, and 1 part of silicone masterbatch. First, dry the nano-graphite and polyoxymethylene powder at 80℃ for 4 hours. Dilute the silane coupling agent with ethanol and impregnate the chopped carbon fiber in it. Then, mix the dried nano-graphite, polyoxymethylene powder, and chopped carbon fiber impregnated with silane coupling agent with polyamide, polyoxymethylene, molybdenum disulfide, antioxidant 1010, and silicone masterbatch in a high-speed mixer at 80℃~100℃. 15 minutes; The mixed raw materials are melt-blended using a twin-screw extruder. The twin-screw extruder uses segmented temperature control: feeding section 200℃ → compression section 230℃ → homogenization section 220℃ → die head 210℃; The melt-blended raw materials are then injection molded in the slots at an injection temperature of 230℃~250℃ and a mold temperature of 80℃~100℃; The holding pressure is 60MPa~80MPa, which allows the composite wear-resistant material to be mechanically embedded in the slots.

[0037] S3, the flat end face of the copper liner is chamfered (0.8×25°); the inner wall of the copper liner is ground to remove injection molding defects; finally, ultrasonic cleaning and polishing are performed; thus, the copper liner inlaid wear-resistant bushing is obtained.

[0038] Example 2 A method for preparing a copper-lined wear-resistant bushing includes the following steps S1 to S3.

[0039] S1 uses a seamless aluminum alloy tube with a wall thickness of 2mm as the base material. After cutting and polishing, an annular aluminum outer base with an inner hole roughness Ra≤1.6μm is obtained. Using a copper plate with a thickness of 2mm as the base material, after punching, rolling, joining and polishing, an annular copper liner with an outer circle roughness Ra≤1.6μm is obtained. The copper liner has uniformly distributed holes and grooves. The end of the hole and groove near the aluminum outer base is an outwardly flared horn shape. A temperature difference assembly method is used (the aluminum outer base is heated to 100°C, while the copper liner is at room temperature) to assemble the aluminum outer base and the copper liner into a single unit, forming a composite aluminum-copper sleeve in which the aluminum outer base is fitted over the copper liner.

[0040] S2, weigh out 60 parts of polyamide (PA66), 15 parts of polyoxymethylene (POM), 3 parts of nano-graphite, 8 parts of polytetrafluoroethylene powder, 2 parts of molybdenum disulfide, 10 parts of chopped carbon fiber, 0.5 parts of silane coupling agent, 0.5 parts of antioxidant 1010, and 1 part of silicone masterbatch. First, dry the nano-graphite and polyoxymethylene powder at 80℃ for 4 hours. Dilute the silane coupling agent with ethanol and impregnate the chopped carbon fiber in it. Then, mix the dried nano-graphite, polyoxymethylene powder, and chopped carbon fiber impregnated with silane coupling agent with polyamide, polyoxymethylene, molybdenum disulfide, antioxidant 1010, and silicone masterbatch in a high-speed mixer at 80℃~100℃. 15 minutes; The mixed raw materials are melt-blended using a twin-screw extruder. The twin-screw extruder uses segmented temperature control: feeding section 200℃ → compression section 230℃ → homogenization section 220℃ → die head 210℃; The melt-blended raw materials are then injection molded in the slots at an injection temperature of 230℃~250℃ and a mold temperature of 80℃~100℃; The holding pressure is 60MPa~80MPa, which allows the composite wear-resistant material to be mechanically embedded in the slots.

[0041] S3, the aluminum outer base flat end face is chamfered (0.8×25°), and the copper liner flat end face is chamfered (0.8×25°); four points are evenly distributed on the outer wall of the aluminum outer base using a Φ3 ball head, and four sets of fixed points with a depth of 0.5mm are applied; during the dotting operation, the inner wall of the copper liner is protected with a solid shaft; the outer wall of the aluminum outer base and the inner wall of the copper liner are ground to remove injection molding inlay defects and dotting defects; finally, ultrasonic cleaning and polishing are performed; the copper liner inlaid wear-resistant bushing is obtained.

[0042] Example 3 The only difference between this embodiment and Embodiment 2 is that the amount of each component in the composite wear-resistant material is adjusted in step S2; the other steps and conditions are the same as in Embodiment 2.

[0043] In step S2 of this embodiment, the amounts of each component in the composite wear-resistant material are as follows: 65 parts of polyamide (PA66), 12.5 parts of polyoxymethylene (POM), 5 parts of nano-graphite, 5 parts of polytetrafluoroethylene powder, 3 parts of molybdenum disulfide, 6 parts of chopped carbon fiber, 1 part of silane coupling agent, 0.5 parts of antioxidant 1010, and 2 parts of silicone masterbatch.

[0044] Example 4 The only difference between this embodiment and Embodiment 2 is that the amount of each component in the composite wear-resistant material is adjusted in step S2; the other steps and conditions are the same as in Embodiment 2.

[0045] In step S2 of this embodiment, the amounts of each component in the composite wear-resistant material are as follows: 70 parts of polyamide (PA66), 10 parts of polyoxymethylene (POM), 4 parts of nano-graphite, 6.5 parts of polytetrafluoroethylene powder, 2 parts of molybdenum disulfide, 5 parts of chopped carbon fiber, 0.7 parts of silane coupling agent, 0.3 parts of antioxidant 1010, and 1.5 parts of silicone masterbatch.

[0046] Example 5 The only difference between this embodiment and embodiment 2 is that in step S1, interference fit is used to assemble the aluminum outer base and the copper liner into one piece, forming a composite aluminum-copper sleeve with the aluminum outer base fitted over the copper liner. The other steps and conditions are the same as in embodiment 2.

[0047] Comparative Example 1 The only difference between this comparative example and Example 2 is that polyoxymethylene (POM) is removed from the composite wear-resistant material of S2; the other steps and conditions are the same as in Example 1.

[0048] Comparative Example 2 The only difference between this comparative example and Example 2 is that polytetrafluoroethylene powder is removed from the composite wear-resistant material of S2; the other steps and conditions are the same as in Example 2.

[0049] Comparative Example 3 The only difference between this comparative example and Example 2 is that molybdenum disulfide is removed from the composite wear-resistant material of S2; the other steps and conditions are the same as in Example 2.

[0050] Comparative Example 4 The only difference between this comparative example and Example 2 is that the short-cut carbon fibers and silane coupling agent, as well as the impregnation treatment steps of the two, are removed from the composite wear-resistant material of S2. The other steps and conditions are the same as those in Example 2.

[0051] Comparative Example 5 The only difference between this comparative example and Example 2 is that antioxidant 1010 is removed from the composite wear-resistant material of S2; the other steps and conditions are the same as in Example 2.

[0052] Comparative Example 6 The only difference between this comparative example and Example 2 is that the silicone masterbatch is removed from the composite wear-resistant material of S2; the other steps and conditions are the same as in Example 2.

[0053] The bushings prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were subjected to performance testing. The results are shown in Table 1 below, including: (1) The interfacial peeling torsional force is tested by the bond strength torsional test method; (2) The coefficient of friction, the test method / standard is GB / T 7948-2024 "Limit PV Test Method for Plastic Sleeves of Sliding Bearings"; (3) Wear amount, the test method / standard is GB / T 7948-2024 "Limit PV Test Method for Plastic Sleeves of Sliding Bearings"; (4) Rust prevention: Refer to GB / T10125-2021 "Artificial Atmosphere Corrosion Test Salt Spray Test" to atomize the sample in a controlled environment with a 5% sodium chloride neutral solution and test for 500 hours to see if there is red rust.

[0054] Table 1

[0055] As shown in Table 1, Examples 1 to 5, the copper-lined wear-resistant bushing prepared by this invention exhibits an interfacial peeling torsional force ≥3.7 N·m; a friction coefficient ≤0.15; a wear amount ≤0.011 mm; and no red rust after 500 hours of neutral salt spray testing. Furthermore, it complies with environmental protection standards GB / T 30512-2014. The copper-lined wear-resistant bushing prepared by this invention can be applied to oil-free bearings, and is particularly suitable for harsh environments with high requirements for rust prevention and lightweighting, such as aerospace and low-altitude aircraft.

[0056] Comparing Comparative Examples 1 to 6 with Example 2, it can be seen that after deleting any component from the composite wear-resistant material filled in the copper liner, the interfacial peeling torsional force of the resulting bushing decreased to varying degrees, while the coefficient of friction and wear increased to varying degrees.

[0057] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A copper-lined wear-resistant bushing, characterized in that, The copper-lined wear-resistant bushing includes a copper liner with grooves and holes, and a composite wear-resistant material is inlaid in the grooves. The composite wear-resistant material comprises the following parts by weight: 60-70 parts of polyamide; 10 to 15 parts of polyoxymethylene; 3 to 5 parts of nano-graphite; 5 to 8 parts of polytetrafluoroethylene powder; 2 to 3 parts of molybdenum disulfide; 5 to 10 parts of chopped carbon fiber; 0.5 to 1 part of silane coupling agent; Antioxidant 0.3 to 0.5 parts; 1 to 2 parts lubricant.

2. The copper-lined wear-resistant bushing according to claim 1, characterized in that, The antioxidant is antioxidant 1010; the lubricant is silicone masterbatch.

3. The copper-lined wear-resistant bushing according to claim 1, characterized in that, The copper-lined wear-resistant bushing also includes an aluminum outer base, which is fitted over the copper-lined bushing and assembled as a whole.

4. A method for preparing a copper-lined wear-resistant bushing according to any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: S1, Prepare an annular copper liner, and machine uniformly distributed holes and grooves on the working surface of the copper liner; S2, composite wear-resistant material is mechanically embedded in the grooves by injection molding; S3, the flat end face and inner and outer walls of the copper liner are machined and cleaned to obtain a copper liner inlaid with a wear-resistant bushing.

5. The method for preparing a copper-lined wear-resistant bushing according to claim 3, characterized in that, S1 also includes: the prepared annular aluminum outer base, which is then assembled into a whole by interference fit or temperature difference fit, with the aluminum outer base fitted over the copper liner; S3 also includes: machining the flat end face and outer wall of the aluminum outer base.

6. The method for preparing a copper-lined wear-resistant bushing according to claim 5, characterized in that, The specific steps of S1 are as follows: S11 uses seamless aluminum alloy tubes as the base material, and after cutting and polishing, it obtains an annular aluminum outer base with an inner hole roughness Ra≤1.6μm; S12, using copper plate as substrate, is processed by punching, rolling, joining and polishing to obtain an annular copper liner with an outer surface roughness Ra≤1.6μm, and the copper liner has uniformly distributed holes and grooves. The end of the groove near the aluminum outer base is flared outwards in the shape of a trumpet.

7. The method for preparing a copper-lined wear-resistant bushing according to claim 4, characterized in that, The specific steps of the injection molding method described in S2 are as follows: S21, Weigh the raw materials of the composite wear-resistant material according to the proportion; S22, nano-graphite and polytetrafluoroethylene powder are first dried; short-cut carbon fibers are impregnated with a silane coupling agent solution diluted with ethanol. S23 and S22 dried nano-graphite, polytetrafluoroethylene powder, and short-cut carbon fibers impregnated with silane coupling agent are mixed with polyamide, polyoxymethylene, molybdenum disulfide, antioxidant, and lubricant in a high-speed mixer. S24 uses a twin-screw extruder to melt-blend the mixed raw materials; S25 involves injection molding molten blended raw materials into slots, resulting in the mechanical embedding of composite wear-resistant materials within the slots.

8. The method for preparing a copper-lined wear-resistant bushing according to claim 7, characterized in that, The twin-screw extruder uses segmented temperature control, with the feeding section temperature at 200℃±5℃, the compression section temperature at 230℃±5℃, the homogenization section temperature at 220℃±5℃, and the die head temperature at 210℃±5℃. The injection molding conditions include: injection temperature of 230℃~250℃, mold temperature of 80℃~100℃, and holding pressure of 60MPa~80MPa.

9. The method for preparing a copper-lined wear-resistant bushing according to claim 5, characterized in that, The specific steps of S3 are as follows: S31, perform outer chamfering on the flat end face of the aluminum outer base and inner chamfering on the flat end face of the copper liner; S32, using a ball head to evenly distribute dots on the outer wall of the aluminum outer base, applying at least four sets of fixing points; S33, the outer wall of the aluminum base and the inner wall of the copper liner are ground to remove injection molding inlay defects and dotting defects; S34, ultrasonic cleaning and polishing.

10. The method for preparing a copper-lined wear-resistant bushing according to claim 9, characterized in that, The depth of the fixing point is 0.4mm~0.6mm; During the dotting operation, a solid shaft is used to protect the inner wall of the copper liner.

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