Electrically conductive fibers for bearing electrocorrosion protection, methods of making and using the same

Abstract

The application discloses a kind of electrically conductive fibers for bearing electrocorrosion protection, its preparation method and application.The electrically conductive fibers include: fiber matrix and the metal layer of fiber matrix coating;Metal layer continuously coats the side surface and at least one end surface of fiber matrix.Electrically conductive brush includes: the electrically conductive fiber bundle formed by the cluster of multiple electrically conductive fibers and current collector;Current collector is fixedly connected with the first end of electrically conductive fiber bundle and is conducted, and the end surface of one of the electrically conductive fibers coated by metal layer is arranged at the second end of electrically conductive fiber bundle away from current collector.The end surface of the electrically conductive fiber provided by the application does not exist exposed fiber material, and the contact surface with bearing is continuous covering metal layer when bearing electrocorrosion protection is carried out, so compared with the embodiment that nickel-plated carbon fiber is cut and clustered in prior art, the technical scheme provided by the application can provide better electrical conductivity, thermal conductivity and wear resistance, and better bearing electrocorrosion protection effect can be realized.

Description

Technical Field

[0001] This invention relates to the field of composite fiber technology, and in particular to a conductive fiber for bearing electro-corrosion protection, its preparation method and application. Background Technology

[0002] Currently, electric vehicles are leading the development of new energy vehicles, and it is expected that pure electric will remain the mainstream power technology for decades to come. Furthermore, with the voltage platform of electric vehicles increasing from 400V to 800V, the vehicles now offer numerous advantages, including faster charging speeds, higher motor speeds, higher power density, and lighter weight thanks to less wiring.

[0003] While the aforementioned advantages help alleviate range anxiety in electric vehicles, they also bring other derivative problems. Currently, not all electric vehicle drive motors operating at 400V will experience electrolytic corrosion; this largely depends on the specific design. However, drive motors operating on an 800V platform can easily achieve high speeds of 20,000 rpm. Due to the influence of shaft voltage, the probability of bearing electrolytic corrosion (without additional protective measures) will directly double, leaving almost no chance of survival.

[0004] To address the aforementioned issues, shaft voltage can currently be managed primarily through three methods: conduction, blocking, and suppression. In comparison, using conductive fibers for conduction offers advantages such as low cost, broad applicability, and strong protective capabilities, thus gaining widespread attention and application.

[0005] The existing technologies primarily focus on the structural design of electrical corrosion protection devices for motor bearings, with little coverage of the conductive fibers that play a crucial role in these devices. Currently, most manufacturers of these protective devices use nickel-plated carbon fiber, which is typically cut into sections according to requirements and assembled onto the protective device. However, due to variations in assembly processes, the quality of the nickel-plated carbon fiber, and structural design, its critical wear resistance and conductivity performance vary considerably. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a conductive fiber for bearing electro-corrosion protection, its preparation method, and its application.

[0007] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0008] In a first aspect, the present invention provides a conductive fiber for bearing electro-corrosion protection, comprising: a fiber matrix and a metal layer covering the fiber matrix; the metal layer continuously covers the side surface and at least one end face of the fiber matrix.

[0009] Secondly, the present invention also provides a conductive brush for bearing electro-corrosion protection, comprising: a conductive fiber bundle formed by a plurality of the above-mentioned conductive fiber bundles and a current collector; the current collector is fixedly connected to and conducts through a first end of the conductive fiber bundle, and one end face of the conductive fiber covered by a metal layer is disposed at a second end of the conductive fiber bundle away from the current collector.

[0010] Thirdly, the present invention also provides a method for preparing the above-mentioned conductive brush, comprising:

[0011] Provide a fiber matrix and bundle multiple fiber matrices together to form a matrix fiber bundle;

[0012] The matrix fiber bundle is brought into contact with an electrolyte containing metal ions, and a metal layer is deposited on the sides and at least one end face of multiple fiber matrices in the matrix fiber bundle by electroplating or chemical plating to obtain a conductive fiber bundle.

[0013] The conductive fiber bundle is fixedly connected to the current collector and made conductive.

[0014] Fourthly, the present invention also provides a drive motor, including a bearing and a conductive structure in conductive contact with the bearing, the conductive structure being at least used to prevent electrical corrosion of the bearing; the conductive structure includes the aforementioned conductive brush.

[0015] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention include at least the following:

[0016] The conductive fiber provided by this invention has no exposed fiber material on its end face. When performing bearing electro-corrosion protection, the contact surface with the bearing is a continuously covered metal layer. Therefore, compared with the prior art of cutting and bundling nickel-plated carbon fiber, the technical solution provided by this invention can provide better conductivity, thermal conductivity and wear resistance, and can achieve a better bearing electro-corrosion protection effect.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the end face state of the conductive fiber provided in a typical embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the preparation process of a conductive brush provided in a typical embodiment of the present invention;

[0020] Explanation of reference numerals in the attached drawings: 1. Clamp; 2. Matrix fiber bundle; 3. Electrolyte; 4. Second end; 5. Metal conductor; 6. Shear line; 7. Current collector; 8. Crimping part; 9. Conductive fiber bundle; 10. Contact end; 11. End face. Detailed Implementation

[0021] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0023] In existing technologies, it is necessary to utilize the elasticity of the fiber matrix and the electrical and thermal conductivity of the coating to prepare an electro-corrosion protection structure so that the conductive fibers can fully contact the bearing surface and conduct current and heat during motor use. For example, it is common knowledge that nickel-plated carbon fibers are cut into segments and bundled together to form an electrical contact fiber bundle for bearing electro-corrosion protection. However, after practical experience, the inventors of this invention found that the application effect of this fiber is still not ideal. The most critical factor is that after cutting the nickel-plated carbon fibers into segments, the cross-sectional end structure of the conductive fiber is a composite structure of metal layer and carbon fiber. As a result, after assembly, 99% of the contact area between the conductive fiber and the motor drive shaft is a carbon fiber material surface with weak conductivity, poor thermal conductivity, and poor wear resistance. Furthermore, the metal layer at the cross-sectional end is discontinuous, and the coating is easily detached under the high-speed rotation and wear of the drive shaft, thereby increasing the risk of electro-corrosion. The cut conductive fibers are prone to loosening, resulting in a high assembly difficulty and increased production costs. Using a single type of metallic nickel, the conductive fiber lacks good electrical and thermal conductivity.

[0024] To address the aforementioned issues, this invention proposes a wear-resistant, high-performance conductive fiber for bearing electro-corrosion protection, along with its preparation method, based on the specific application scenarios and functional requirements of electro-corrosion protection devices. By composited with a metal layer on the surface, the prepared conductive fiber exhibits excellent performance. The metal layer at the contact surface between the conductive fiber and the drive shaft is continuous, providing better conductivity and wear resistance. The assembled electrical connection ends are wrapped with copper conductive tape for easy crimping. A sizing agent with resistance to oil contamination and a bundling effect is applied to the surface of the conductive fiber, solving the problems of loose fibers causing difficulty in assembly and fiber damage and breakage generating excessive dust, thus affecting the cleanliness of the motor's internal working environment.

[0025] For the reasons mentioned above, see Figure 1 and Figure 2As shown, an embodiment of the present invention provides a conductive fiber for bearing electro-corrosion protection, comprising: a fiber matrix and a metal layer covering the fiber matrix; the metal layer continuously covers the side surface and at least one end face 11 of the fiber matrix.

[0026] In some embodiments, the fiber matrix has a diameter of 6-7 μm and a length that can be selected as needed. Usually, for ease of processing, it can be longer than the fiber bundle length in the final application. Finally, the non-friction end is cut.

[0027] In some embodiments, the thickness of the metal layer on the side surface is 0.1-1 μm, and the thickness of the metal layer on the end surface is 0.1-1.2 μm.

[0028] In some embodiments, the fiber matrix material includes any one or a combination of two or more of carbon fiber, carbon nanotube fiber, graphene fiber, silicon carbide fiber, basalt fiber, and organic polymer fiber.

[0029] In some implementations, the metal layer is made of any one or a combination of two or more of copper, nickel, chromium, silver, and gold.

[0030] In some embodiments, the metal layer includes a metal conductive layer and a metal wear-resistant layer sequentially stacked along a direction away from the fiber matrix; the material of the metal conductive layer is selected from any one or a combination of two or more of copper, silver, and gold.

[0031] The material of the metal wear-resistant layer is selected from any one or a combination of two or more of nickel and chromium.

[0032] In some embodiments, the thickness of the metal conductive layer is 0.3-0.5 μm, and the thickness of the metal wear-resistant layer is 0.1-0.5 μm.

[0033] In some embodiments, a metal interlayer, such as a flash-plated nickel layer, is provided between the conductive metal layer and the wear-resistant metal layer.

[0034] As a further application of the above-mentioned conductive fibers, this embodiment of the invention also provides a conductive brush for bearing electro-corrosion protection, which includes: a conductive fiber bundle 9 formed by a bundle of conductive fibers provided in any of the above embodiments and a current collector 7; the current collector 7 is fixedly connected to and conducts through a first end of the conductive fiber bundle 9, and one end face 11 of the conductive fiber covered by a metal layer is disposed at a second end 4 of the conductive fiber bundle 9 away from the current collector 7.

[0035] In some embodiments, the number of bundles of the conductive fiber bundle 9 is 12-36.

[0036] In some embodiments, the length of the conductive fiber bundle 9 is 3-8 mm.

[0037] In some embodiments, the first end of the conductive fiber bundle 9 is surrounded and wrapped by a metal conductor 5 so that the first end is bundled together.

[0038] In some embodiments, the conductive fiber bundle 9 further contains a sizing agent that at least binds the middle sections of the conductive fiber bundle 9 together.

[0039] Corresponding to the above conductive brush structure, embodiments of the present invention also provide a method for preparing the conductive brush provided in any of the above embodiments, which includes the following steps:

[0040] Provide a fiber matrix and bundle multiple fiber matrices together to form a matrix fiber bundle 2.

[0041] The matrix fiber bundle 2 is brought into contact with an electrolyte 3 containing metal ions, and a metal layer is deposited on the sides and at least one end face 11 of the multiple fiber substrates in the matrix fiber bundle 2 by electroplating or chemical plating to obtain a conductive fiber bundle 9.

[0042] The conductive fiber bundle 9 is fixedly connected to the current collector 7 and made conductive.

[0043] In some embodiments, the preparation method may specifically include the following steps:

[0044] The steps include sequentially depositing a conductive metal layer and a wear-resistant metal layer on the surface of the fiber matrix.

[0045] In some implementations, the metallic conductive layer is deposited using a chemical copper plating method.

[0046] In some implementations, the metal wear-resistant layer is deposited using a high-phosphorus electroless nickel deposition process.

[0047] In some preferred embodiments, the process may further include: after sizing and bundling the nickel-plated conductive fiber bundle 9, grinding its end face 11 to expose the nickel plating layer, and then electroplating a hard metal layer such as chromium onto the exposed end face 11, with a thickness of, for example, 50-200 nm. This enhances the wear resistance of the fiber bundle and avoids the problem of fiber bundle dispersion caused by poor bonding between the hard metal layer and the sizing agent (compared to overall chromium plating followed by sizing).

[0048] As some typical application examples of the above technical solutions, such as Figure 2 As shown, the above preparation method may include, for example, the following specific implementation process:

[0049] 1) After the fiber matrix is ​​bundled and fixed on the fixture 1, conductive fibers are prepared. For example, carbon fibers are cut into the required lengths and assembled and fixed on the fixture 1. The fixture 1 can oscillate periodically at a set frequency when performing liquid treatment, including electroplating, chemical plating, cleaning and other processes. This can disperse the carbon fibers in the reagents of each process and avoid the occurrence of "black heart" phenomena such as missed plating. Since one end of the carbon fiber is always immersed in each treatment reagent, metal can also be deposited on its cross-section.

[0050] 2) First, the surface of the fiber matrix is ​​pretreated, such as removing oil, sizing agent and other impurities from the fiber matrix surface; for example, the carbon fiber treated in step 1 is immersed in an acetone reagent bath to remove the sizing agent and grease from the carbon fiber surface, and the treatment time is 30s to 2min; using acetone can remove the sizing agent and grease at the same time, reducing the number of pretreatment processes, reducing the risk of carbon fiber breakage, and maintaining the original mechanical properties of carbon fiber.

[0051] 3) Using chemical plating or electroplating, copper, which has good electrical and thermal conductivity, and nickel, which enhances the environmental resistance of the conductive fiber, are sequentially laminated onto the surface of the fiber. The ends of the conductive fiber that contact the drive shaft are also covered with the aforementioned metal coating, resulting in a continuous metal plating layer across the entire conductive fiber.

[0052] For example, the carbon fibers treated in step 2 are thoroughly washed with water, and then placed in a catalytic solution at a temperature of 25–33°C for 3–6 minutes. The catalytic solution includes a palladium-containing catalyst at a concentration of 2–5 ml / L, 37% hydrochloric acid at a concentration of 200–300 ml / L, sodium chloride at a concentration of 40–60 g / L, and stannous chloride at a concentration of 2–4 g / L. More preferably, the palladium-containing catalyst includes palladium chloride at a concentration of 5–12 g / L, hydrochloric acid at a concentration of 120–260 mL / L, sodium chloride at a concentration of 30–80 g / L, and stannous chloride at a concentration of 5–13 g / L.

[0053] The activated carbon fibers are thoroughly washed with water, and then placed in a desiccant solution at a temperature of 27–54°C for 30 seconds to 3 minutes. The desiccant solution includes an accelerator with a concentration of 15–25 g / L and concentrated sulfuric acid with a volume fraction of 1.6–2.6%.

[0054] More preferably, the accelerator comprises a stannous sulfate and / or stannous sulfate solution with a concentration of 150–300 g / L.

[0055] The degummed carbon fibers are thoroughly washed with water and then immersed in a chemical copper plating solution at 48–53°C for 3–7 minutes. The chemical copper plating solution comprises copper ions at a concentration of 2.2–2.7 g / L, ethylenediaminetetraacetic acid (EDTA) at a concentration of 0.11–0.13 mol / L, sodium hydroxide at a concentration of 4.5–6 g / L, formaldehyde at a concentration of 3.5–4.5 g / L, and methanol at a concentration of 10–20 mL / L. Copper sulfate provides copper ions, EDTA acts as a complexing agent, sodium hydroxide adjusts the pH to ensure the reducing power of formaldehyde under alkaline conditions, and methanol acts as a stabilizer. Conductive fibers are prepared by laminating copper metal onto the surface of the carbon fibers, providing good electrical and thermal conductivity, ensuring the conduction of conductive devices and the heat transfer and dissipation during high-speed motor operation.

[0056] The copper-plated carbon fibers are thoroughly washed with water, and then placed in an electroplating nickel solution at a temperature of 45-55°C for 1-7 minutes. The electroplating nickel solution includes nickel ions at a concentration of 70-90 g / L, boric acid at a concentration of 25-35 g / L, nickel chloride at a concentration of 5-15 g / L, and a pH of 4.0-4.5.

[0057] The nickel-plated carbon fibers are thoroughly washed with water, and then immersed in a nickel plating solution at 85–92°C for 1–10 minutes. The nickel plating is a high-phosphorus nickel plating with a phosphorus content of 9–12%, comprising 20–30 g / L nickel sulfate, 25–35 g / L sodium hypophosphite, 10–20 g / L sodium acetate, 20–25 g / L citric acid, 3–6 mL / L lactic acid, 3–6 mL / L OP, and a pH of 4.5–5.0. For the high-speed friction environment during operation of the conductive fibers, a high-phosphorus nickel plating with good wear resistance is selected.

[0058] The carbon fiber is then thoroughly washed with water, and then placed in an oven at 110-120°C for 3-5 minutes to dry and remove moisture.

[0059] To further improve the conductivity and abrasion resistance of the conductive fibers, the fibers were placed in a post-treatment oven and subjected to dehydrogenation and annealing sequentially under a protective atmosphere. First, 10–20 sccm of hydrogen and 100–150 sccm of argon were introduced into the oven, with the dehydrogenation temperature set at 230–260°C and the treatment time at 2–4 hours for coating treatment. Subsequently, only 150–200 sccm of argon was introduced, and the annealing temperature was set at 350–450°C for 2–4 hours for coating annealing.

[0060] Copper conductive tape is wrapped around the electrical connection ends of the conductive fibers to facilitate crimping.

[0061] The conductive fibers are then treated with a corrosion-resistant sizing agent to bundle them together and prevent them from loosening. For example, the conductive fibers treated above are immersed in a tank containing 5% sizing agent for 5 to 10 seconds. The sizing agent is prepared according to the following weight ratio, which mainly contains E44 epoxy resin, dodecylamine-modified EP, polyvinylpyrrolidone, and acetone in a weight ratio of 10:2:4:60.

[0062] Finally, the conductive fiber is dried at 40-50℃ for 5-15 minutes to complete the preparation. The fiber bundle is then cut along the shear line 6 and pressed onto the current collector 7 to form the pressing part 8.

[0063] As a further specific application of the above technical solution, embodiments of the present invention also provide a drive motor, including a bearing and a conductive structure in conductive contact with the bearing, the conductive structure being at least used to prevent electro-corrosion of the bearing; the conductive structure includes the conductive brush provided in any of the above embodiments. Specifically, one end face 11 of the conductive brush, covered by a metal layer, is in electrical contact with the bearing, thereby providing excellent electrical and thermal conductivity while maintaining excellent wear resistance.

[0064] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0065] Example 1

[0066] Example 1 of this embodiment describes the preparation process of copper-nickel plated carbon fiber for bearing electro-corrosion protection, as shown below:

[0067] 1. Mount the carbon fiber onto the adjustable oscillation frequency fixture 1 and set the frequency to 20 times / min. This fixture must be turned on when performing surface treatment in reagent tanks or water washing tanks.

[0068] 2. Soak in acetone for 2 minutes to remove the sizing agent from the carbon fiber surface and then wash.

[0069] 3. Treat the above fibers in a catalytic reagent for 3 minutes and then wash them.

[0070] 4. Treat the fiber degumming agent above for 2 minutes, and then rinse.

[0071] 5. Treat the above fibers in a chemical copper reagent for 7 minutes to deposit a copper plating layer with a thickness of about 400 nm, and then clean them.

[0072] 6. Treat the above fibers in a chemical nickel reagent for 4 minutes to deposit a nickel plating layer with a thickness of about 150 nm, and then clean them.

[0073] 7. Dry for 5 minutes at 110℃.

[0074] 8. Introduce 20 sccm of hydrogen and 120 sccm of argon into the oven, set the temperature to 250℃, and process for 3 hours to remove hydrogen from the coating. Then, introduce only 200 sccm of argon, set the annealing temperature to 400℃, and process for 3 hours to anneal the coating.

[0075] 9. After sizing for 5 seconds, dry in an oven at 50℃ for 10 minutes to obtain the finished conductive fiber. Finally, wrap copper conductive tape around the crimping end, cut it off from fixture 1, and assemble it onto the conductive ring to form a ring-shaped conductive brush.

[0076] The conductive fiber a prepared by the above method and the conductive fiber b formed by bundling nickel-plated carbon fiber segments to form the contact end 10 without a metal layer were respectively assembled on a conductive ring for comparative testing.

[0077] The tests include static resistance, dynamic resistance, and forward and reverse impact assessment of wear resistance (5000 revolutions forward and reverse wear for 1 hour).

[0078] The test results are shown in Tables 1-3 below:

[0079] Table 1 Static resistance test results

[0080] Test product Static resistance (Ω) conductive fiber a 0.0013 Conductive fiber b 0.0140

[0081] Table 2 Dynamic resistance test results

[0082]

[0083]

[0084] Table 3 Results of impact and abrasion resistance tests during forward and reverse rotation.

[0085]

[0086] The test results in the three tables above show that the static and dynamic resistance values ​​of the conductive fibers prepared by the method of the present invention are relatively small. After the forward and reverse impact wear resistance test, the static resistance change value of the fiber wear length is small and the performance is stable.

[0087] Example 2

[0088] This embodiment provides a preparation process for copper-plated nickel-chromium carbon fiber for bearing electro-corrosion protection, which is largely the same as that in Embodiment 1, with the only difference being:

[0089] After sizing and drying to form conductive fiber bundle 9, the end face 11 that is used to contact the bearing is first polished repeatedly on a grinding wheel in both forward and reverse directions to expose the nickel plating layer. After exposing the nickel-plated end face 11, a chromium plating process is used to plate the end face 11 with a thickness of about 100 nm to prepare conductive fiber c.

[0090] The test results for the conductive fiber c are shown in Tables 4 and 5 below.

[0091] Table 4. Dynamic resistance test results

[0092]

[0093] Table 5 Results of impact and abrasion resistance tests during forward and reverse rotation.

[0094]

[0095]

[0096] It can be seen that although a chromium plating layer was added at the end, the contact resistance was slightly increased due to the slightly weaker contact conductivity of chromium. However, the increase in resistance did not affect the actual antistatic application. Furthermore, the addition of the chromium plating layer on the end face significantly improved the wear resistance of the fiber bundle. The rate of change of static resistance before and after wear (0.0029 / 0.0025) was much lower than that in Example 1 (0.0020 / 0.0013). This indicates that the antistatic fiber bundle prepared by the embodiment provided in this example is more suitable for long-term wear application scenarios, such as electric vehicles.

[0097] Comparative Example 1

[0098] This comparative example is largely the same as Example 2, except that the chromium plating process is set after electroless nickel plating and before sizing to prepare conductive fiber d.

[0099] At this point, although the chromium plating layer is mainly concentrated at the end due to the concentrated current at the end, a small amount of chromium plating layer will still be deposited on the entire side of the fiber. Therefore, after sizing, the chromium plating layer and the sizing agent do not bond well. During the operation of the bearing, the bundle is easy to disperse, which will lead to insufficient resistance and a significant increase in dynamic resistance.

[0100] The specific test results are shown in Tables 6 and 7 below.

[0101] Table 6. Dynamic Resistance Test Results

[0102]

[0103] Table 7 Results of Impact and Abrasion Resistance Tests (Forward and Reverse Rotation)

[0104]

[0105]

[0106] It can be observed that by first plating the hard material with chromium and then sizing and bundling, the resulting fiber bundles have a poorer bundling effect due to the influence of a small amount of chromium plating on the fiber sides, which affects the final high speed resistance and wear resistance. This also shows that the bundling effect of the sizing agent is quite important for achieving better application results.

[0107] Based on the above embodiments and comparative examples, it is clear that the end face 11 of the conductive fiber provided in the embodiments of the present invention does not have exposed fiber material. When performing bearing electro-corrosion protection, the contact surface with the bearing is a continuously covered metal layer. Therefore, compared with the prior art implementation of cutting and bundling nickel-plated carbon fiber, the technical solution provided by the present invention can provide better conductivity, thermal conductivity and wear resistance, and can achieve a better bearing electro-corrosion protection effect.

[0108] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a conductive brush, characterized in that, include: Provide a fiber matrix and bundle multiple fiber matrices together to form a matrix fiber bundle; The matrix fiber bundle is brought into contact with an electrolyte containing metal ions, and a metal layer is deposited on the side surfaces and at least one end surface of multiple fiber matrices in the matrix fiber bundle by electroplating or chemical plating. The metal layer includes a metal conductive layer and a metal wear-resistant layer stacked sequentially along the direction away from the fiber matrix. The metal wear-resistant layer is deposited by high-phosphorus chemical nickel deposition to obtain a conductive fiber bundle. After the nickel-plated conductive fiber bundles are sized and bundled, their end faces are polished to expose the nickel plating layer. Then, a hard metal layer is deposited by electroplating on the exposed end face nickel plating layer. The conductive fiber bundle, after the deposition of the hard metal layer, is fixedly connected to the current collector and made conductive.

2. The preparation method according to claim 1, characterized in that, The diameter of the fiber matrix is ​​6-7 μm; And / or, on the side surface, the thickness of the metal layer is 0.1-1 μm, and on the end face, the thickness of the metal layer is 0.1-1.2 μm.

3. The preparation method according to claim 1, characterized in that, The fiber matrix material includes any one or a combination of two or more of the following: carbon fiber, carbon nanotube fiber, graphene fiber, silicon carbide fiber, basalt fiber, and organic polymer fiber.

4. The preparation method according to claim 1, characterized in that, The material of the metal conductive layer is selected from any one or a combination of two or more of copper, silver, and gold. The thickness of the conductive metal layer is 0.3-0.5 μm, and the thickness of the wear-resistant metal layer is 0.1-0.5 μm.

5. The preparation method according to claim 1, characterized in that, The current collector is fixedly connected to and conducts through the first end of the conductive fiber bundle, and one end face of the fiber matrix covered by a metal layer is disposed at the second end of the conductive fiber bundle away from the current collector.

6. The preparation method according to claim 5, characterized in that, The number of bundles of the conductive fiber is 12-36; And / or, the length of the conductive fiber bundle is 3-8 mm.

7. The preparation method according to claim 5, characterized in that, The first end of the conductive fiber bundle is also surrounded and wrapped by a metal conductor.

8. The preparation method according to claim 1, characterized in that, The conductive metal layer is deposited using a chemical copper plating method.

9. The preparation method according to claim 1, characterized in that, Also includes: The step of annealing the metal layer specifically includes: performing a first annealing treatment in a hydrogen-containing atmosphere at a temperature of 230-260℃ for 2-4 hours, followed by a second annealing treatment in a protective atmosphere at a temperature of 350-450℃ for 2-4 hours.

10. A drive motor, comprising a bearing and a conductive structure in conductive contact with the bearing, the conductive structure being at least used to prevent electro-corrosion of the bearing; Its features are, The conductive structure includes a conductive brush prepared by the preparation method according to any one of claims 1-9.

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