Device and method for preparing composite fiber and composite fiber

Abstract

The invention provides a preparation device and method of composite fibers and the composite fibers. The preparation device comprises a discharging module, an electroplating module, a collecting module and a tension control module. The discharging module is used for providing bundled fiber bundles; the electroplating module is used for electroplating the fiber bundles so as to form metal layers on the fiber bundles; the material receiving module is used for carrying out rolling treatment on the fiber bundles subjected to electroplating treatment; and the tension control module is used for controlling the discharging module and / or the receiving module to continuously apply axial tension to the advancing fiber bundles, so that the fiber bundles are kept in a bundling state in the advancing process. According to the invention, the axial tension is continuously applied to the fiber bundle in the electroplating process, so that the plated metal layer can realize the structural bundling of fibers, and the defect that the fibers bundled by depending on a sizing agent are easy to bend and deform under severe working conditions such as high temperature and oil immersion is fundamentally eliminated; therefore, the reliability and the service life of the composite fiber are improved.

Description

Technical Field

[0001] This invention relates to the field of composite fiber technology, and in particular to an apparatus, method, and composite fiber preparation method. 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 volumes of cooling oil 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 and nickel) as the brush filaments of conductive rings. To meet the needs of subsequent processing (such as cutting and assembly), a sizing agent (such as epoxy, polyacrylic acid, polyurethane, polyetheretherketone, polyimide, etc.) is usually coated on the surface of the coated fiber as a bundling layer to achieve bundling between the individual filaments. However, this method has at least two drawbacks: First, most sizing agents are resin-based. When the brush filaments come into contact with the motor, the high temperature generates organic sizing agents that carbonize into particles. These particles are trapped in the brush filaments of the conductive ring, which will aggravate the abrasive wear of the brush filaments and reduce the life of the conductive ring. Second, 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 conductive function to fail. Summary of the Invention

[0006] To improve the performance and service life of composite fiber filaments, this invention provides an apparatus, method, and composite fiber for preparing composite fibers.

[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 preparation apparatus, comprising a feeding module, an electroplating module, a receiving module, and a tension control module; The feeding module is used to provide bundled fiber bundles; The electroplating module is used to electroplat the fiber bundle to form a metal layer on the fiber bundle; The receiving module is used to wind up the fiber bundles after electroplating. The tension control module is used to control the feeding module and / or the receiving module to continuously apply a predetermined axial tension to the fiber bundle in motion, so that the fiber bundle remains in a bundled state during motion.

[0008] Furthermore, the electroplating module includes: An electroplating tank for containing an electroplating solution, wherein a metal anode is disposed in the electroplating solution and the metal anode is connected to the positive terminal of a DC power supply; and At least one conductive guiding element is provided at the inlet end of the electroplating tank. The conductive guiding element is used to guide the fiber bundle to travel in the electroplating tank and is connected to the negative terminal of the DC power supply.

[0009] Furthermore, the electroplating tank includes a mother electroplating tank and a sub-electroplating tank nested within the mother electroplating tank, wherein a U-shaped cavity is formed between the mother electroplating tank and the sub-electroplating tank, and the bottom of the sub-electroplating tank is provided with a first liquid circulation mechanism for circulating the electroplating liquid in the mother electroplating tank to the sub-electroplating tank, and the sidewalls of the mother electroplating tank and the sub-electroplating tank are respectively provided with slits for at least one fiber bundle to enter and exit.

[0010] Furthermore, the outlet end of the electroplating tank is also provided with the conductive guiding element; and / or The output end of the feeding module and the input end of the receiving module are respectively provided with insulating guiding elements.

[0011] Furthermore, the preparation apparatus also includes a cleaning module and a drying module sequentially disposed between the electroplating module and the receiving module; The cleaning module includes a cleaning tank for containing cleaning fluid to clean the electroplated fiber bundles. The drying module is used to dry the fiber bundles after they have been cleaned.

[0012] Furthermore, the cleaning tank includes a cleaning mother tank and a cleaning daughter tank nested within the cleaning mother tank, wherein a U-shaped cavity is formed between the cleaning mother tank and the cleaning daughter tank, the bottom of the cleaning daughter tank is provided with a second liquid circulation mechanism for circulating the cleaning liquid in the cleaning mother tank to the cleaning daughter tank, and the side walls of the cleaning mother tank and the cleaning daughter tank are respectively provided with slits for at least one fiber bundle to enter and exit.

[0013] Furthermore, an insulating guiding element is provided between the cleaning module and the drying module.

[0014] Furthermore, the fiber bundles provided by the feeding module are glue-free fiber bundles.

[0015] Secondly, the present invention provides a method for preparing composite fibers, based on the aforementioned preparation apparatus, the preparation method comprising: The bundled fiber bundles are provided by the feeding module; The fiber bundle is electroplated using an electroplating module to form the metal layer on the fiber bundle; The electroplated fiber bundles are wound up using a take-up module. During the movement of the fiber bundle, the feeding module and / or the receiving module are controlled by the tension control module to continuously apply a predetermined axial tension to the moving fiber bundle, so that the fiber bundle remains in a bundled state during movement.

[0016] Thirdly, the present invention provides a composite fiber, which is prepared using the preparation apparatus described above.

[0017] By adopting the above technical solution, the present invention has at least the following beneficial effects: The preparation apparatus and method of the present invention continuously apply axial tension to the fiber bundle during its electroplating process, causing it to straighten along the axial direction. This allows the fiber bundle to maintain a tightly bundled state (i.e., "rod-like") during its journey. In this state, the fibers are close together, the gaps are reduced, and the metal deposits on the surfaces of adjacent fibers easily come into contact and bridge each other during growth, thus physically connecting multiple fibers like "welding". This allows a continuous three-dimensional metal network to be formed on the sides and between the fibers, providing a structural consolidation effect. Therefore, it is possible to bundle the fibers together along the axial direction without relying on any sizing agent. This fundamentally eliminates the defects of using sizing agents, such as pyrolysis and carbonization (generating abrasive particles) or bending deformation under harsh conditions such as high temperature and oil immersion, thereby improving the reliability and service life of the composite fiber. Attached Figure Description

[0018] 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

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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%.

[0025] 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.

[0026] 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 that it can still work reliably under various complex and harsh working conditions in the engine compartment.

[0027] 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.

[0028] However, most sizing agents are resin-based. When the brush bristles come into contact with the motor, the high temperature generates organic sizing agents that carbonize into particles. These particles become trapped in the brush bristles of the conductive ring, accelerating abrasive wear and reducing the lifespan of the conductive ring. Furthermore, while metal-plated 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.

[0029] 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.

[0030] 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.

[0031] 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".

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Based on this, the present invention provides a composite fiber preparation apparatus, method, and composite fiber. By continuously applying tension to the fiber bundle during the plating process to keep the fiber bundle in a bundled state, the plating metal layer itself can achieve full-length structural bundle of the fiber filaments, fundamentally avoiding problems such as material thermal degradation, performance decline, and aggravated wear caused by the use of sizing agents, thereby significantly improving its performance as a conductive brush filament material under long-term harsh working conditions.

[0038] Example 1 This embodiment provides a preparation apparatus for preparing composite fibers, see reference. 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.

[0039] 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.

[0040] 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, providing a basis for the final formation of a metal layer 22 that provides structural consolidation.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] In one feasible manner, such as Figure 1C and 1D 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.

[0045] In one feasible manner, such as Figure 1E and 1FAs 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Example 2 Based on the aforementioned preparation apparatus, this embodiment provides a method for preparing composite fibers, specifically including 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.

[0053] 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.

[0054] The method of this embodiment applies and maintains a constant axial tension throughout the entire process of fiber bundle 21 travel, so that it maintains a tightly bundled "rod-like" shape during electroplating (the bundled effect can be adjusted by controlling the tension of 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 pyrolysis, aging and "collapse" failure caused by sizing agents.

[0055] like Figure 1A and Figure 1BAs 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.

[0056] 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.

[0057] Table 1

[0058] 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.

[0059] Example 3 This embodiment provides a composite fiber, which can be used as follows: Figures 1A-1F It is prepared using the apparatus shown.

[0060] 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 problems such as pyrolysis carbonization, abrasive wear, and environmental aging caused by reliance on sizing agents.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] Example 4 This embodiment provides a conductive mechanism, including a substrate having at least one mounting through-hole and a composite fiber as provided in Embodiment 3. The composite fibers are mounted one-to-one within the mounting through-holes, with one end of each composite fiber extending out of the mounting through-hole.

[0066] In this embodiment, the conductive mechanism includes, but is not limited to, a conductive ring or a conductive block. For example... Figure 3As shown, the conductive mechanism is a conductive ring, which includes a ring body assembly 31 and brush filaments 32. The brush filaments 32 are implemented using the composite fibers provided in Embodiment 3. 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.

[0067] The conductive ring provided in this embodiment uses composite fibers formed by the aforementioned continuous metal layer 22 as brush bristles 32, which fundamentally avoids 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 shape under complex working conditions, fundamentally avoiding the failure caused by carbonization (abrasive wear) and aging (collapse) of traditional brush bristles 32 due to sizing agents. Stability and contact reliability, along with high conductivity ensuring efficient current conduction, ultimately enable the conductive ring to achieve long lifespan and high operational reliability. Table 2 below shows the durability test results of the conductive ring in this embodiment. Table 2

[0068] 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.

[0069] 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.

[0070] Example 5 This embodiment provides a motor, which includes a rotating shaft and a conductive mechanism as provided in Embodiment 4. 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.

[0071] 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.

[0072] 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.

[0073] 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. An apparatus for preparing composite fibers, characterized in that, It includes a feeding module, an electroplating module, a receiving module, and a tension control module; The feeding module is used to provide bundled fiber bundles; The electroplating module is used to electroplat the fiber bundle to form a metal layer on the fiber bundle; The receiving module is used to wind up the fiber bundles after electroplating. The tension control module is used to control the feeding module and / or the receiving module to continuously apply axial tension to the fiber bundle in motion, so that the fiber bundle remains in a bundled state during its motion.

2. The preparation apparatus according to claim 1, characterized in that, The electroplating module includes: An electroplating tank for containing an electroplating solution, wherein a metal anode is disposed in the electroplating solution and the metal anode is connected to the positive terminal of a DC power supply; and At least one conductive guiding element is provided at the inlet end of the electroplating tank. The conductive guiding element is used to guide the fiber bundle to travel in the electroplating tank and is connected to the negative terminal of the DC power supply.

3. The preparation apparatus as described in claim 2, characterized in that, The electroplating tank includes a mother electroplating tank and a sub-electroplating tank nested within the mother electroplating tank. A U-shaped cavity is formed between the mother electroplating tank and the sub-electroplating tank. The bottom of the sub-electroplating tank is provided with a first liquid circulation mechanism for circulating the electroplating liquid in the mother electroplating tank to the sub-electroplating tank. The side walls of the mother electroplating tank and the sub-electroplating tank are respectively provided with slits for at least one fiber bundle to enter and exit.

4. The preparation apparatus as described in claim 2 or 3, characterized in that, The electroplating tank's outlet end is also equipped with the aforementioned conductive guiding element; and / or The output end of the feeding module and the input end of the receiving module are respectively provided with insulating guiding elements.

5. The preparation apparatus according to claim 1, characterized in that, The preparation apparatus further includes a cleaning module and a drying module sequentially disposed between the electroplating module and the receiving module; The cleaning module includes a cleaning tank for containing cleaning fluid to clean the electroplated fiber bundles. The drying module is used to dry the fiber bundles after they have been cleaned.

6. The preparation apparatus as described in claim 5, characterized in that, The cleaning tank includes a main cleaning tank and a sub-cleaning tank nested within the main cleaning tank. A U-shaped cavity is formed between the main cleaning tank and the sub-cleaning tank. The bottom of the sub-cleaning tank is provided with a second liquid circulation mechanism for circulating the cleaning liquid in the main cleaning tank to the sub-cleaning tank. The side walls of the main cleaning tank and the sub-cleaning tank are respectively provided with slits for at least one fiber bundle to enter and exit.

7. The preparation apparatus as described in claim 5 or 6, characterized in that, An insulating guiding element is provided between the cleaning module and the drying module.

8. The preparation apparatus according to claim 1, characterized in that, The fiber bundles provided by the feeding module are glue-free fiber bundles.

9. A method for preparing composite fibers, implemented using the preparation apparatus according to any one of claims 1-8, characterized in that, The preparation method includes: The bundled fiber bundles are provided by the feeding module; The fiber bundle is electroplated using an electroplating module to form the metal layer on the fiber bundle; The electroplated fiber bundles are wound up using a take-up module. During the movement of the fiber bundle, the tension control module controls the feeding module and / or the receiving module to continuously apply axial tension to the moving fiber bundle, so that the fiber bundle remains in a bundled state during movement.

10. A composite fiber, characterized in that, The composite fiber is prepared using the preparation apparatus described in any one of claims 1-8.

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