Composite fiber and preparation method thereof, conductive mechanism and motor

Abstract

The invention provides a composite fiber and a preparation method thereof, a conductive mechanism and a motor, the composite fiber comprises: a fiber bundle, the fiber bundle comprising a plurality of fibers; the metal layer is continuously coated on the outer peripheral surfaces of the fibers and among the fibers, and the fibers are bundled together in the axial direction by the metal layer; wherein the fiber bundle is formed in a way that the stiffness of the composite fiber is not less than 200mm under the condition that the bundling layer is not arranged and the content of the metal layer is not less than 50%. Therefore, structural bundling of the fibers is achieved through the metal layer, the defect that fibers bundled through a sizing agent are prone to bending deformation under the severe working conditions of high temperature, oil immersion and the like is fundamentally overcome, the reliability of the composite fibers is improved, and the service life of the composite fibers is prolonged.

Description

Technical Field

[0001] This invention relates to the field of composite fiber technology, and in particular to a composite fiber, its preparation method, a conductive mechanism, and an electric motor. Background Technology

[0002] Carbon fiber was invented in the late 1950s. Due to its unique and excellent properties, such as high specific strength, high specific modulus, low density, high temperature resistance, radiation resistance, good toughness, good electrical and thermal conductivity, and low coefficient of thermal expansion, it has attracted widespread attention. Metal-coated carbon fiber is a composite fiber with metal coated on its surface. It inherits the excellent properties of carbon fiber, such as high specific strength, high specific modulus, and good toughness, while retaining the characteristics of the metal coating, further expanding the application fields of carbon fiber.

[0003] Currently, the new energy vehicle industry is leading the steady advancement of electrification. The 800V high-voltage platform has become the mainstream, and the development trend of electric drives is towards high voltage, high speed, high frequency control, and high power density. As a result, electric drives face more severe challenges such as premature insulation decay, electromagnetic compatibility, NVH, heat dissipation, and bearing electrocorrosion, which promotes the innovation of materials technology.

[0004] Protection against bearing electro-corrosion mainly involves methods such as diversion, restriction, and blocking. Among these, integrating conductive rings (or conductive brushes) into electric drive systems to divert shaft current is relatively economical and effective, and therefore widely used. However, given the trend of coaxial or parallel-axis electric drive bridge structures in electric drive systems gradually developing towards larger shaft diameters, conductive rings will face more severe operating conditions: higher linear speeds at the same rotational speed mean higher friction temperatures; and larger coolant volumes mean more severe erosion wear, cavitation wear, and other corrosive wear.

[0005] Currently, the industry commonly uses composite fibers formed by coating carbon fiber with metals (such as copper or nickel) as the brush filaments for conductive rings. To meet the needs of subsequent processing (such as cutting and assembly), a sizing agent (such as epoxy, polyacrylic acid, polyurethane, polyetheretherketone, or polyimide systems) is usually coated onto the surface of the coated fibers as a bundling layer to achieve bundling between the individual filaments. Although metal-coated carbon fiber itself has good stability, its outer sizing agent has poor environmental tolerance. After long-term use under harsh working conditions (such as oil immersion), its mechanical properties (such as elastic modulus) may change significantly, making it more prone to bending, deformation, or even "collapse," thus detaching from the effective contact area and causing the conductivity to fail. Summary of the Invention

[0006] To improve the performance of composite fibers, this invention provides a composite fiber, a method for preparing the same, a conductive mechanism, and a motor.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a composite fiber, comprising: Fiber bundle, the fiber bundle comprising multiple fiber filaments; and A metal layer is continuously coated on the outer peripheral surface of each fiber and between each fiber, and the fiber is bundled together along the axial direction. The fiber bundle is formed such that, without a bundle-gathering layer, when the content of the metal layer is not less than 50%, the stiffness of the composite fiber is not less than 200 mm.

[0008] Furthermore, the content of the metal layer is 55%-85%; And / or, the line resistance of the composite fiber is not higher than 1.0 Ω / m.

[0009] Furthermore, the material of the metal layer is selected from at least one of copper, nickel, aluminum, zinc, silver, gold, tin, nickel-cobalt, and nickel-chromium; The fiber material is selected from at least one of carbon fiber, metal fiber and organic fiber, and the organic fiber includes at least one of polyester, acrylic, nylon, polypropylene, aramid, ultra-high molecular weight polyethylene fiber, PBO fiber, PBI fiber, M5 fiber and PI fiber. And / or, the number of the fibers is 1K-60K.

[0010] Furthermore, the metal layer is formed by electroplating. During the formation of the metal layer, the fiber bundles are kept in a bundled state under a predetermined axial tension of 5N-10N.

[0011] Secondly, the present invention provides a method for preparing the composite fiber as described above, comprising: The fiber bundles are provided in a bundled manner; The fiber bundle is electroplated to form the metal layer on the fiber bundle; The electroplated fiber bundle is then wound up. During the movement of the fiber bundle, axial tension is continuously applied to the fiber bundle to keep it in a bundled state.

[0012] Furthermore, during the travel of the fiber bundle, the fiber bundle is made to travel at a speed of 0.15m / min - 0.5m / min; During the travel of the fiber bundle, an axial tension of 5N-10N is continuously applied to the fiber bundle; and / or When electroplating the fiber bundle, a current of 10A-30A is applied to the fiber bundle.

[0013] Furthermore, before the winding process, the method further includes: sequentially cleaning and drying the electroplated fiber bundle.

[0014] Thirdly, the present invention provides a conductive mechanism, comprising: A substrate having at least one mounting through-hole; and Composite fibers as described above; The composite fibers are installed one-to-one in the mounting through holes, and one end of each composite fiber extends out of the mounting through hole.

[0015] Furthermore, the conductive mechanism is a conductive ring or a conductive block.

[0016] Fourthly, the present invention provides an electric motor, including a rotating shaft and a conductive mechanism as described above.

[0017] By adopting the above technical solution, the present invention has at least the following beneficial effects: (1) A composite fiber is provided, wherein the bundled nature of the fiber bundle can be achieved by the metal layer continuously filled between the fiber filaments, and the bundled nature of the fiber bundle is formed such that even without additional coating of sizing agent as a bundled layer, when the content of the metal layer is not less than 50%, the stiffness of the composite fiber is not less than 200 mm, thereby preventing the composite fiber from bending, deforming or even "falling over" under long-term harsh working conditions, and providing a stable and reliable conductive material for key components such as conductive rings.

[0018] (2) A method for preparing the aforementioned composite fiber is provided. By continuously applying axial tension to the fiber bundle during its travel, the fiber bundle can be straightened along the axial direction, thus maintaining a tightly bundled state (i.e., "stick-shaped") during its travel. In this state, the fibers are close to each other, the gaps are reduced, and the metal deposits on the surfaces of adjacent fibers can easily come into contact and bridge each other during the growth process, thereby physically connecting multiple fibers like "welding". This allows a continuous three-dimensional metal network to be formed on the sides of the fibers and between the fibers to play a structural consolidation role. Therefore, it is possible to bundle the fibers together along the axial direction without relying on any sizing agent.

[0019] (3) A conductive mechanism using the aforementioned composite fiber as brush bristles is provided, thereby achieving a significant improvement in the reliability and durability of the conductive mechanism.

[0020] (4) A motor including the aforementioned conductive mechanism is provided, which can fundamentally enhance the bearing electro-corrosion protection capability and the shaft current can be efficiently and stably discharged, thereby improving the operational reliability and service life of the entire electric drive system under harsh conditions such as high voltage and high speed. Attached Figure Description

[0021] Figure 1A This is a top view schematic diagram of the composite fiber preparation apparatus in this application; Figure 1B This is a schematic diagram of the longitudinal cross-sectional structure of the composite fiber preparation apparatus in this application; Figure 1C This is a side view of the electroplating tank in this application; Figure 1D This is a top view of the electroplating tank in this application; Figure 1E This is a side view of the cleaning tank in this application; Figure 1F This is a top view of the cleaning tank in this application; Figure 2 This is a schematic diagram of the composite fiber structure in this application; Figure 3 This is a schematic diagram of the conductive ring in this application; Figure 4 This is a schematic diagram of the test results of the shaft voltage during the durability process of the conductive ring in this application. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0023] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the actual number, shape and size of the components, the shape, quantity, positional relationship and proportion of each component can be arbitrarily changed under the premise of realizing the technical solution of this invention, and the layout of the components may also be more complex.

[0024] As is well known, using traditional metal materials as brush bristles for conductive rings (such as copper, silver alloys, or single-metal bristles) has the following drawbacks: poor wear resistance and lifespan; direct friction between metals (motor shafts are usually made of steel) easily generates wear powder (abrasive debris), leading to poor contact and shortened lifespan; severe wear on the shaft; direct friction between hard metals can scratch or wear the motor shaft at high speeds, potentially affecting the shaft's mechanical strength and dynamic balance; and contact stability is easily affected by oil contamination, as the oil film formed on the contact surface can act as an insulator, resulting in unstable current conduction.

[0025] Besides metal brush filaments, another common traditional solution is to use carbon materials as conductive brush filaments (such as pure carbon brushes). However, it also has obvious shortcomings: poor conductivity, pure carbon materials have high resistivity, resulting in high power consumption and heat generation when conducting large currents. Due to the high resistivity, the voltage drop is greater under the same current. Low strength, pure carbon brushes have low mechanical strength, are not impact-resistant, and are easily broken. The problem of detachment is serious, as carbon brush wear will produce conductive carbon powder, which will contaminate the inside of the motor and may cause short circuits.

[0026] In summary, neither traditional metals nor pure carbon brush filaments can achieve an ideal balance between conductivity, wear resistance, mechanical strength, and environmental reliability. Therefore, the industry has begun exploring the application of composite fibers formed from metal-plated carbon fibers in conductive rings. Practice has shown that this material solution effectively combines the advantages of carbon fiber and metal coatings, and its key features are mainly reflected in the following aspects: 1) Excellent wear resistance: This is one of its core advantages. By adding lubricating substances to the metal layer and the outer resin layer, the conductive monofilament can effectively reduce friction when it moves relative to other components. Experiments show that after 2000 hours of forward and reverse wear testing, the wear of the metallized carbon fiber can be less than 0.2 mm, thus ensuring the stable operation of the conductive ring throughout the entire lifespan of the motor.

[0027] 2) Stable and efficient conductivity: Metallization treatment has greatly improved the conductivity of carbon fiber, reducing its DC resistance to below 1Ω / m. This makes the static resistance between the bearing guard ring and the shaft much less than 1Ω, which can efficiently conduct the shaft current that damages the bearing and reduce the occurrence rate of related failures by about 90%.

[0028] 3) Excellent flexibility and contact reliability: Metallized carbon fiber itself has the characteristics of being soft and resistant to bending. Combined with careful structural design, it can ensure that the conductive parts and the high-speed rotating shaft always maintain a tight and stable contact and will not fail due to vibration or long-term use.

[0029] 4) Strong environmental resistance: The metal-coated carbon fiber material can withstand high and low temperature impacts ranging from -70℃ to 280℃ for extended periods, and its surface shows no corrosion after 192 hours of acidic salt spray testing. This ensures its reliable operation under various complex and harsh working conditions in the engine compartment.

[0030] In the existing composite fiber preparation process, in order to disperse the fiber filaments in the electroplating bath and achieve a uniform electroplating effect, it is necessary to reduce the tension of the fiber filaments during the composite process. However, this will result in insufficient fiber bundles. In a loose state, metal ions are deposited on the surface of each isolated fiber filament, and the fibers are not connected to each other. Therefore, an additional sizing agent is needed to improve the bundle properties of the finished composite fiber for later use.

[0031] However, while metallized carbon fiber itself has good stability, its outer sizing agent has poor environmental tolerance. After long-term use under harsh conditions (such as oil immersion), its mechanical properties (such as elastic modulus) may change significantly, making it more prone to bending, deformation, and even "collapse," thus detaching from the effective contact area and causing conductivity failure. Moreover, most sizing agents are resin-based, and the high temperature generated when the brush bristles come into contact with the motor will carbonize the organic sizing agent into particles. These particles, trapped in the brush bristles of the conductive ring, will accelerate abrasive wear on the brush bristles and reduce the life of the conductive ring.

[0032] In particular, the "collapse" problem is prone to occur in oil-cooled environments. "Collapse" refers to the phenomenon where the metal-plated composite carbon fiber (conductive brush filaments) of the conductive ring becomes soft and unable to maintain its preset shape and angle under the continuous impact and immersion of the cooling oil, thus deviating from or detaching from its contact position with the shaft. This failure phenomenon is mainly caused by the following factors: First and foremost, the most direct factor is the continuous impact of fluid dynamics. The interior of an oil-cooled motor is filled with high-speed circulating cooling oil. This continuous oil flow generates significant fluid resistance and shear force on the delicate conductive brush bristles, which can easily lead to plastic deformation of the bristles over a long period of time.

[0033] Secondly, changes in lubrication conditions exacerbate the instability of the brush bristles. In an oil-cooled environment, the cooling oil itself acts as an excellent lubricant, significantly reducing the static friction between the brush bristles and the shaft. When the friction is insufficient to support the brush bristles against the aforementioned oil flow impact, the bristles are easily "pushed over," making it difficult to maintain stable contact pressure.

[0034] Most importantly, the environmental tolerance of traditional metal-plated carbon fiber outer coating agents is poor. After long-term immersion in an oil-cooled environment, their mechanical properties are prone to decline, causing the bristles to soften and bend more easily, thus accelerating the occurrence of "collapse".

[0035] Through research and improvement, the inventors realized that the existing technical approach of "dispersing and coating first, then bonding and bundling" is the root cause of the long-standing "sizing agent defect" dilemma in this field. To completely solve the problems of pyrolysis and aging caused by sizing agents, it is necessary to break free from dependence on sizing agents. The prerequisite for breaking free from dependence is that the fiber bundle itself already possesses excellent and stable bundling properties when the coating is completed.

[0036] Based on this, the inventors changed their technical approach and proposed a highly creative reverse concept: during the electroplating process, instead of reducing the tension, they actively applied and maintained a high tension, forcing the fiber bundles to always maintain a tightly bundled "stick-like" shape as they passed through the electroplating zone.

[0037] The inventors discovered that under axial tension (5N-10N), the fiber bundles already bundled at the unwinding end will be straightened and tightly clustered together, with the microscopic gaps between the fibers becoming smaller, more regular, and stable. When this tightly bundled fiber is used as a cathode in an electroplating solution, the current can still be evenly distributed. More importantly, in this state, metal ions not only deposit on the surface of each fiber, but also, due to the extremely small spacing between the fibers, the metal grains growing on the surfaces of adjacent fibers easily come into contact, bridge, and eventually merge, thus constructing a continuous, three-dimensional metal network in situ within the fiber bundle. This metal network acts like countless tiny "welding points," physically binding the multiple fibers of the fiber bundle into a whole and encapsulating the entire fiber bundle together.

[0038] Therefore, applying tension is not merely adding a process parameter, but a completely new composite mechanism that allows electroplating, originally intended to coat the surface of fibers with a metal layer, to simultaneously assume the role of "structural consolidation." By precisely controlling parameters such as tension and current density, the thickness and density of the metal network can be adjusted, thereby directly obtaining integrated composite fibers with high metal content (≥50%), high stiffness (≥200mm), good conductivity (line resistance ≤1.0 Ω / m), and completely independent of any sizing agent.

[0039] The above technical concept completely breaks away from the traditional mindset that requires the use of sizing agents for bundling. By creating a specific physical state of fiber bundles (tightly bundled under high tension), the electroplating process itself achieves the simultaneous construction of function (conductivity) and structure (bundling), opening up a completely new technical path for the preparation of high-performance, highly reliable conductive brush filament materials.

[0040] Based on this, the present invention provides a composite fiber and its preparation method, a conductive mechanism and a motor. By continuously applying tension to the fiber bundle during the plating process, the fiber bundle is kept in a bundled state, so that the plating metal layer itself can achieve full-length structural bundle of the fiber filaments, thereby significantly improving its performance as a conductive brush filament material under long-term harsh working conditions.

[0041] Example 1 This embodiment provides a composite fiber, which can be used as follows: Figures 1A-1F It is prepared using the apparatus shown.

[0042] In this embodiment, as Figure 2 As shown, the composite fiber includes a fiber bundle 21 and a metal layer 22. The fiber bundle 21 includes multiple fiber filaments. The metal layer 22 continuously covers the outer peripheral surface of each fiber filament and between each fiber filament, and bundles the fiber filaments together axially (the fiber filaments are closely arranged) to form a self-supporting overall structure. The bundled nature of the fiber bundle 21 is such that even without additional coating of the bundled layer (sizing agent) on the composite fiber, when the content of the metal layer 22 is not less than 50%, the stiffness of the composite fiber is not less than 200 mm, thereby avoiding the problem of collapsing caused by reliance on sizing agents.

[0043] In this embodiment, the composite fiber is structurally bonded together by the metal layer 22, which continuously covers and fills the fiber bundle 21 along its axial direction, forming a self-supporting, integrated rod-like structure through metal bonding. This structure not only endows it with a high metal content (≥50%, preferably 55%-85%) and high stiffness (≥200mm) to resist external fluid impact and effectively solve the risk of "collapse," but also ensures excellent conductivity (line resistance ≤1.0 Ω / m). This significantly improves its long-term reliability, wear resistance, and service life in dynamic contact scenarios such as conductive rings, making it particularly suitable for harsh working conditions such as high pressure, high speed, and oil cooling.

[0044] In one feasible embodiment, the material of the metal layer 22 may be selected from at least one of the metals such as copper, nickel, aluminum, zinc, silver, gold, tin, nickel cobalt, and nickel chromium; the material of the fiber may be selected from at least one of carbon fiber, metal fiber, and organic fiber. Organic fiber includes at least one of the fibers such as polyester, acrylic, nylon, polypropylene, aramid, ultra-high molecular weight polyethylene fiber, PBO (poly(p-phenylenebenzobisoxazole)) fiber, PBI (poly(p-phenylenebenzoimidazolium)) fiber, M5 (phenylenepyridinium diimidazolium) fiber, and PI (polyimide) fiber. This embodiment does not limit the specific fiber selection.

[0045] In one possible implementation, this embodiment does not limit the number of fibers contained in the fiber bundle 21. For example, the number of fibers can be 1K-60K, including 1k, 1.5k, 1.8k, 3k, 60K, 12k, 24k, 30k, 48k, 50k, 60k, etc., where 1k represents 1000.

[0046] In this embodiment, the metal layer 22 is formed by electroplating. During the formation of the metal layer 22, the multiple fibers of the fiber bundle 21 are kept tightly bundled under a predetermined axial tension (such as 5N-10N). This ensures that even without additional bundled layers, the composite fiber has a stiffness of not less than 200mm when the content of the plated metal layer 22 is not less than 50%, which significantly improves the reliability of the composite fiber.

[0047] It should be noted that this embodiment does not exclude the possibility of applying a sizing agent to further enhance the performance of the composite fiber.

[0048] Example 2 This embodiment provides a method for preparing the aforementioned composite fiber, which can be based on, as follows: Figures 1A-1F The preparation apparatus shown is used to implement this process. Before introducing the preparation method of this embodiment, the preparation apparatus will first be described as follows: See Figures 1A-1F As shown, the preparation apparatus mainly includes a feeding module 11, an electroplating module 13, a take-up module 17, and a tension control module (not shown). The feeding module 11 provides the bundled fiber bundles 21; the electroplating module 13 electroplats the fiber bundles 21 to form a metal layer 22 on them; the take-up module 17 winds up the electroplated fiber bundles 21; and the tension control module controls the speed of the feeding module 11 and / or the take-up module 17 to continuously apply an adjustable axial tension to the traveling fiber bundles 21, ensuring that the fiber bundles 21 remain tightly bundled during travel.

[0049] Because of the integrated tension control module, a preset axial tension can be applied and maintained on the fiber bundle 21 online and dynamically, thereby ensuring that the fiber bundle 21 remains in a tightly bundled "rod-like" state throughout its entry into and passage through the electroplating module 13. Under this tension, the fibers are tightly arranged, and the gaps between the fibers are regular and small. When the fiber bundle 21 is electroplated in this state, metal ions can not only be deposited on the surface of each fiber, but also grow and bridge in the gaps between the closely contacting fibers, thereby forming a continuous metal layer 22 in situ that fills the gaps and solidifies the fibers.

[0050] In one feasible embodiment, the electroplating module 13 includes an electroplating tank 131 and a conductive guiding element 132 disposed at least at the inlet end of the electroplating tank 131. The electroplating tank 131 contains an electroplating solution, in which a metal anode 133 is disposed, connected to the positive terminal of a DC power supply 134. The conductive guiding element 132, shown as a conductive roller, guides the fiber bundle 21 within the electroplating tank 131 and is connected to the negative terminal of the DC power supply 134. During operation, the conductive roller connected to the negative terminal of the power supply, in conjunction with the metal anode 133 connected to the positive terminal within the electroplating tank 131, forms a stable and efficient electroplating reaction environment. Metal ions are uniformly and densely deposited and bridged on the surface and in the gaps between the closely packed fiber filaments, laying the foundation for the final formation of a metal layer 22 that provides structural consolidation.

[0051] In one feasible embodiment, the outlet end of the electroplating tank 131 is also provided with a conductive guiding element 132 connected to the negative terminal of the DC power supply 134, thereby ensuring that the fiber bundle 21 maintains a stable and uniform cathode potential throughout the entire length of the electroplating tank 131. This effectively avoids the problem of the current density gradually decreasing from the inlet end to the outlet end due to the long tank or high resistance, thereby ensuring that the thickness and density of the plated metal layer 22 are highly uniform along the axial direction of the fiber bundle 21.

[0052] In one feasible embodiment, the output end of the feeding module 11 and the input end of the receiving module 17 are respectively provided with insulating guiding elements, thereby providing a smooth, low-friction transition guide for the fiber bundle 21, which helps to maintain the consistent stability of the bundle shape and tension of the fiber bundle 21 throughout the entire path. Preferably, the aforementioned insulating guiding elements can be guide rollers or guide wheels made of ceramic or glass, as shown in FIG1 as insulating guide wheel 12.

[0053] In one feasible embodiment, the preparation apparatus further includes a cleaning module 14 and a drying module 16 sequentially disposed between the electroplating module 13 and the receiving module 17. The cleaning module 14 includes a cleaning tank 141 for containing cleaning solution to clean the electroplated fiber bundles 21; the drying module 16 is used to dry the cleaned fiber bundles 21. This linear layout from feeding, electroplating, cleaning, drying to receiving constitutes a complete continuous production line. The functional modules work collaboratively, achieving integrated, uninterrupted production from raw materials to finished products, significantly improving production efficiency and product consistency. Preferably, an insulating guiding element is also provided between the cleaning module 14 and the drying module 16 to obtain stable physical guidance. This insulating guiding element can also be a guide roller or guide wheel made of ceramic or glass; in Figure 1, an insulating guide roller 15 is shown.

[0054] In one feasible manner, such as Figure 1C and1D As shown, the electroplating tank 131 includes a mother electroplating tank 1311 and a daughter electroplating tank 1312 nested within the mother electroplating tank 1311, with a U-shaped cavity 1313 formed between the mother electroplating tank 1311 and the daughter electroplating tank 1312. The bottom of the daughter electroplating tank 1312 is provided with a first liquid circulation mechanism 1314 for circulating the electroplating solution in the mother electroplating tank 1311 to the daughter electroplating tank 1312. The side walls of the mother electroplating tank 1311 and the daughter electroplating tank 1312 are respectively provided with slits 1315a for at least one fiber bundle 21 to enter and exit in a straight line.

[0055] In one feasible manner, such as Figure 1E and 1F As shown, the cleaning tank 141 includes a main cleaning tank 1411 and a sub-cleaning tank 1412 nested within the main cleaning tank 1411, with a U-shaped cavity 1413 formed between the main cleaning tank 1411 and the sub-cleaning tank 1412. The bottom wall of the sub-cleaning tank 1412 is provided with a second liquid circulation mechanism 1414 for circulating the cleaning liquid in the main cleaning tank 1411 to the sub-cleaning tank 1412. The side walls of the main cleaning tank 1411 and the sub-cleaning tank 1412 are respectively provided with slits 1315b for at least one fiber bundle 21 to enter and exit in a straight line.

[0056] In one feasible embodiment, each slit 1315a, 1315b opens from the top to the bottom of the corresponding sidewall, and the bottoms of all slits 1315a, 1315b are located on the same horizontal plane, with the fiber bundle 21 traveling close to the bottom of the corresponding slit. The electroplating tank 131 and the cleaning tank 141 may each have multiple slits arranged side-by-side. Figure 1C and Figure 1E As shown, the electroplating tank 131 and the cleaning tank 141 are respectively provided with three cuts side by side to provide channels for the three fiber bundles 21 to pass through (one channel for one fiber bundle to pass through). Similarly, if N channels are needed, N proportional cuts are opened side by side. The number of channels depends on the actual needs, and this embodiment does not limit this.

[0057] In this embodiment, the width of a slit is configured to allow a bundle of fibers 21 maintaining a rod-like shape to pass through. This embodiment achieves parallel processing of multiple fiber bundles 21 through a multi-channel setup, significantly improving production efficiency while ensuring that each fiber bundle 21 undergoes completely consistent process conditions, thereby guaranteeing a high degree of uniformity in the performance of mass-produced products.

[0058] During operation, excess electroplating solution in the electroplating sub-tank 1312 flows into the electroplating master tank 1311 through a cut in its side wall, and then circulates back into the electroplating sub-tank 1312 via the first liquid circulation mechanism 1314. Excess cleaning solution in the cleaning sub-tank 1412 flows into the cleaning master tank 1411 through a cut in its side wall, and then circulates back into the cleaning sub-tank 1412 via the second liquid circulation mechanism 1414. Furthermore, waste liquid collectors (not shown) are respectively provided at the bottom of the electroplating master tank 1311 and the cleaning master tank 1411 to collect waste liquid flowing out from the cuts in the side walls of the electroplating master tank 1311 and the cleaning master tank 1411.

[0059] In one feasible embodiment, the first liquid circulation mechanism 1314 and the second liquid circulation mechanism 1414 can be implemented by circulation pumps. Each circulation pump is equipped with a corrosion-resistant motor to continuously circulate the electroplating solution / cleaning solution, which can ensure that each fiber can be immersed in the electroplating solution / cleaning solution (the pumped electroplating solution / cleaning solution will make the liquid level higher than the fiber bundle 21 that passes through), and also ensure that the composition, temperature and cleanliness of the electroplating solution and cleaning solution are uniform and stable, thereby maintaining the stability of electroplating and cleaning.

[0060] In one feasible approach, the fiber bundle 21 provided by the feeding module 11 is a glue-free fiber bundle, thereby eliminating the need for high-temperature de-adhesion, reducing contamination and fiber breakage.

[0061] In one feasible embodiment, the tension control module is integrated into one end of the take-up module 17, and tension is precisely adjusted by regulating the winding speed. The tension control module may also include a touchscreen display 18 for human-machine interaction, allowing the user to set the tension level. This embodiment improves the bundle cohesion of the fiber bundle 21 by controlling the tension and metal content, thus eliminating the need for additional sizing agents for bundle cohesion.

[0062] Based on the aforementioned preparation apparatus, the preparation method provided in this embodiment specifically includes the following steps: Step S10: The bundled fiber bundle 21 is provided through the feeding module 11; Step S20: Electroplating is performed on the fiber bundle 21 by the electroplating module 13 to form a metal layer 22 on the fiber bundle 21. In step S30, the electroplated fiber bundle 21 is wound up by the take-up module 17.

[0063] During the movement of the fiber bundle 21, the tension control module controls the feeding module 11 and / or the receiving module 17 to continuously apply axial tension to the fiber bundle 21 so that the fiber bundle 21 remains tightly bundled during movement.

[0064] The method of this embodiment applies and maintains a constant axial tension throughout the movement of the fiber bundle 21, so that it maintains a tightly bundled "rod-like" shape during electroplating (the bundled effect can be adjusted by controlling the tension of the fiber bundle 21). This creates key conditions for the uniform deposition, bridging and formation of a continuous metal layer 22 that plays a consolidation role in the gaps between the fiber filaments of the metal layer 22. It eliminates the dependence on sizing agents and fundamentally eliminates the risk of "collapse" failure caused by sizing agents.

[0065] like Figure 1A and Figure 1B As shown, the fiber bundle 21 starts from the feeding module 11 and remains taut under axial tension throughout the composite process. The tension is adjusted by the tension control module (the axial tension of the fiber bundle 21 is controlled by pneumatic or electric means to maintain it at 5N-10N). When the bundled fiber bundle 21 passes through the electroplating tank 131 with conductive rollers at both ends, metal ions will continuously coat the fiber bundle 21. At this time, the traveling speed is generally controlled at 0.1m / min-0.5m / min, and the constant current applied to the fiber bundle 21 is controlled at 10A-30A. After electroplating, it passes through the cleaning tank 141 to clean away the residual electroplating solution and then is dried to obtain a composite fiber with excellent bundle properties, high metal content (not less than 50%), high stiffness (not less than 200mm), high conductivity (line resistance not higher than 1.0 Ω / m), and high metal toughness.

[0066] In this embodiment, the metal content can be controlled by adjusting the current density applied to the fiber bundle 21. As shown in Table 1, six composite fibers with different processes and different gradient metal contents were prepared using the preparation method of this embodiment, and were used in conductive rings under different environments. For example, composite fibers with low metal content (e.g., less than 50%) were used in conductive rings of dry / air-cooled systems, while composite fibers with high metal content (e.g., not less than 50%) were used in conductive rings of oil-cooled systems, depending on the actual working conditions.

[0067] Table 1

[0068] In this embodiment, stiffness can be tested using the stiffness determination method described in Part 4 of the national standard GB_T 7690.4-2013, Test Methods for Reinforcing Yarns.

[0069] Example 3 This embodiment provides a conductive mechanism, including a substrate having at least one mounting through-hole and a composite fiber as provided in Embodiment 1. The composite fibers are mounted one-to-one within the mounting through-holes, with one end of each fiber extending out of the mounting through-hole.

[0070] In this embodiment, the conductive mechanism includes, but is not limited to, a conductive ring or a conductive block. For example... Figure 3 As shown, the conductive mechanism is a conductive ring, which includes a ring body assembly 31 and brush filaments 32. The brush filaments 32 are made of composite fibers provided in Embodiment 1. The ring body assembly 31 has multiple radially extending mounting through holes 311. The composite fibers are correspondingly installed in the mounting through holes 311, with one end of the composite fiber facing the axis of the ring body assembly 31 extending from the corresponding mounting through hole 311. During assembly, each composite fiber enters from the corresponding mounting through hole 311, is crimped and fixed by a crimping interface 312, and then the excess portion is uniformly cut off by a circular cutter, thereby obtaining composite fibers of equal length as the brush filaments 32 of the conductive ring.

[0071] The conductive ring provided in this embodiment uses composite fibers formed by the aforementioned continuous metal layer 22 as brush bristles 32, fundamentally eliminating the failure caused by the "collapse" of traditional brush bristles 32 due to sizing agents. The high stiffness of the brush bristles 32 ensures their morphological stability and contact reliability under complex working conditions, and their high conductivity ensures efficient current conduction. Ultimately, this results in a long lifespan and high operational reliability for the conductive ring. Table 2 below shows the durability test results of the conductive ring in this embodiment: Table 2

[0072] As shown in Table 2, after nearly 275,000 kilometers of friction with the axial surface, the composite fiber showed a diameter wear of approximately 1.0 mm, a single fiber bundle length wear of approximately 0.5 mm, and a total wear weight of 3.7 mg for a single conductive ring (16 fiber bundles). This demonstrates that the composite fiber used in this embodiment possesses extremely excellent wear resistance. As a conductive brush filament, its size and morphology remain highly stable over an ultra-long lifespan, thus continuously providing reliable electrical contact.

[0073] See Figure 4 As shown, the test results of the shaft voltage during the durability process of the conductive ring in this embodiment are presented. The test results show that after the composite fiber has been rubbed against the shaft surface for nearly 275,000 kilometers, the shaft voltage remains relatively stable, and the voltage drop remains at about 70%, which shows good conductivity.

[0074] Example 4 This embodiment provides a motor, which includes a rotating shaft and a conductive mechanism as provided in Embodiment 3. For example, the conductive motor is... Figure 3 The conductive ring shown has a ring assembly 31 sleeved on a rotating shaft (not shown), and one end of the composite fiber facing the axis of the ring assembly 31 is in electrical contact with the outer peripheral surface of the rotating shaft.

[0075] The motor provided in this embodiment, by integrating the aforementioned conductive mechanism that uses high-performance composite fibers as brush filaments 32, achieves a fundamental improvement in the bearing electro-corrosion protection capability of the electric drive system and an overall leap in system reliability.

[0076] In this specification, the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the descriptions of the embodiments described later are relatively simple, and relevant parts can be referred to the descriptions of the foregoing embodiments.

[0077] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A composite fiber, characterized in that, include: A fiber bundle, the fiber bundle comprising multiple fiber filaments; as well as A metal layer is continuously coated on the outer peripheral surface of each fiber and between each fiber, and the fiber is bundled together along the axial direction. The fiber bundle is formed such that, without a bundle-gathering layer, when the content of the metal layer is not less than 50%, the stiffness of the composite fiber is not less than 200 mm.

2. The composite fiber as described in claim 1, characterized in that, The content of the metal layer is 55%-85%; And / or, the line resistance of the composite fiber is not higher than 1.0 Ω / m.

3. The composite fiber as described in claim 1, characterized in that, The metal layer is made of at least one of copper, nickel, aluminum, zinc, silver, gold, tin, nickel-cobalt, and nickel-chromium. The fiber material is selected from at least one of carbon fiber, metal fiber and organic fiber, and the organic fiber includes at least one of polyester, acrylic, nylon, polypropylene, aramid, ultra-high molecular weight polyethylene fiber, PBO fiber, PBI fiber, M5 fiber and PI fiber. And / or, the number of the fibers is 1K-60K.

4. The composite fiber as described in claim 1, characterized in that, The metal layer is formed by electroplating. During the formation of the metal layer, the fiber bundles are kept in a bundled state under a predetermined axial tension of 5N-10N.

5. A method for preparing composite fibers as described in any one of claims 1-4, characterized in that, include: The fiber bundles are provided in a bundled manner; The fiber bundle is electroplated to form the metal layer on the fiber bundle; The electroplated fiber bundle is then wound up. During the movement of the fiber bundle, axial tension is continuously applied to the fiber bundle to keep it in a bundled state.

6. The preparation method according to claim 5, characterized in that, During the travel of the fiber bundle, the fiber bundle is made to travel at a speed of 0.15m / min - 0.5m / min; During the travel of the fiber bundle, an axial tension of 5N-10N is continuously applied to the fiber bundle; and / or When electroplating the fiber bundle, a current of 10A-30A is applied to the fiber bundle.

7. The preparation method according to claim 5 or 6, characterized in that, Before the winding process, the method further includes: sequentially cleaning and drying the electroplated fiber bundle.

8. A conductive mechanism, characterized in that, include: The substrate has at least one mounting through hole; as well as Composite fibers as described in any one of claims 1-4; The composite fibers are installed one-to-one in the mounting through holes, and one end of each composite fiber extends out of the mounting through hole.

9. The conductive mechanism as described in claim 8, characterized in that, The conductive mechanism is a conductive ring or a conductive block.

10. An electric motor, characterized in that, It includes a rotating shaft and a conductive mechanism as described in claim 8 or 9.

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