A high-damping transmission shaft forming process based on double-material cooperation

Abstract

The application discloses a high-damping transmission shaft forming process based on double-material cooperation, and specific steps of the process are as follows: a carbon fiber-epoxy resin prepreg matrix shaft pipe is prepared, and is formed through layering and segmented curing; 3%-5% carboxylated multi-walled carbon nanotubes are added into nitrile rubber, and after ultrasonic dispersion, the nitrile rubber is filled into an inner cavity of the shaft pipe; the modified rubber is made into a sheet, embedded into a stainless steel mesh and punctured, spirally wound on an outer wall of the shaft pipe and vulcanized to form an outer coating layer; and finally, a connecting flange is assembled. The process adopts a three-layer structure of a carbon fiber composite material matrix shaft pipe, a modified rubber core material and a metal mesh reinforced rubber outer coating layer, heat generated by the core layer is diffused through the outer layer, mechanical protection of the outer layer avoids the core layer from being damaged due to insufficient strength, the strength and rigidity requirements of the transmission shaft are met, and meanwhile, the damping performance and lightweight characteristics of the transmission shaft are considered, and the process is suitable for high-vibration working conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission component manufacturing, in particular to a high-damping transmission shaft forming process based on double-material cooperation. BACKGROUND

[0002] In the field of power transmission, the transmission shaft as a core component plays a key role in the stability and reliability of equipment operation.

[0003] Currently, the research and development of transmission shafts focuses on balancing mechanical properties, damping characteristics, and lightweight requirements, but existing technologies still have significant shortcomings. From the perspective of material application, traditional metal transmission shafts (such as steel and aluminum alloy) have high strength and rigidity, but poor damping performance, which can easily cause noise and fatigue failure under high-frequency vibration conditions, and the high density of metal materials is not conducive to the lightweight upgrade of equipment. Some technical improvement schemes attempt to use carbon fiber composite materials to prepare the transmission shaft body, taking advantage of their high strength and low density to improve mechanical and lightweight indicators, but the damping characteristics of carbon fiber composite materials are limited, making it difficult to effectively suppress vibration, and a single material cannot meet multiple performance requirements. In terms of structural design, to improve damping performance, existing technologies often use rubber-filled or coated composite structures. However, the interface bonding between rubber and base materials such as metal and carbon fiber is a major problem, and there is a lack of effective interface strengthening methods, which can easily cause rubber layer peeling and falling off due to vibration and stress concentration over time, leading to damping performance degradation and affecting the overall life and reliability of the transmission shaft. At the same time, the mechanical strength of rubber materials is low, and without proper reinforcement design, the transmission shaft will lack stiffness and be unable to adapt to high-torque and high-load working conditions. In addition, in terms of preparation process, the problems of interlayer porosity and stress concentration in the prepreg layering process have not been effectively solved, affecting the mechanical properties of the carbon fiber base shaft tube; the modification and dispersion process of rubber materials is not perfect, resulting in unstable damping enhancement effect and making it difficult to achieve precise control and cooperative optimization of material properties.

[0004] Therefore, it is necessary to provide a high-damping transmission shaft forming process based on double-material cooperation to solve the above technical problems. SUMMARY

[0005] The present application aims to provide a high-damping transmission shaft forming process based on double-material cooperation to overcome the shortcomings of poor damping performance, weak interface bonding, and insufficient mechanical properties of existing transmission shafts.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] The application provides a high-damping transmission shaft forming process based on double-material cooperation, the transmission shaft is made of carbon fiber composite material for the base shaft pipe, the inner cavity of the base shaft pipe is filled with rubber, and the outer wall of the base shaft pipe is coated with rubber to form an outer wrapping layer, and the process specifically comprises the following steps:

[0008] Step one: preparing the base shaft pipe

[0009] The carbon fiber composite material is a prepreg composed of carbon fiber and epoxy resin, and the base shaft pipe is prepared through prepreg layering and segmented curing process;

[0010] The mass percentage of the epoxy resin in the prepreg is 30%-50%, the curing temperature of the prepreg is 120-150 DEG C, and the curing pressure is 0.3-0.8 MPa;

[0011] Step two: core filling

[0012] The rubber is modified nitrile rubber, and 3%-5% of carboxylated multi-walled carbon nanotubes are added to the nitrile rubber to form modified nitrile rubber;

[0013] The carboxylated multi-walled carbon nanotubes have a diameter of 10-20 nm and a length-diameter ratio of 50-100, and the modified nitrile rubber is filled into the inner cavity of the base shaft pipe after ultrasonic dispersion treatment;

[0014] Step three: outer wrapping layer forming

[0015] The modified nitrile rubber subjected to ultrasonic dispersion treatment in step two is made into a rubber sheet, a metal mesh is embedded in the rubber sheet, and the rubber sheet embedded with the metal mesh is treated through a puncture-vulcanization process to form an outer wrapping layer, which is wrapped on the outer wall of the base shaft pipe to obtain a transmission shaft body;

[0016] In the puncture-vulcanization treatment process, the puncture density of the puncture needle for the rubber sheet embedded with the metal mesh is 50-100 / cm2, the vulcanization temperature is 140-160 DEG C, and the vulcanization pressure is 2-3 MPa;

[0017] Step four: connecting flange assembly

[0018] The surface of the connecting flange is first sandblasted to enhance the adhesion, and the assembly area of the transmission shaft body is polished to expose the carbon fiber base layer, then the perpendicularity of the connecting flange and the transmission shaft body is calibrated through positioning tooling, and finally the connecting flange and the transmission shaft body are tightened with bolts to be assembled into one.

[0019] As preferred, step one is performed according to the following procedure:

[0020] 1a) Cutting the carbon fiber and epoxy resin composite pre-impregnated material into a pre-impregnated material sheet suitable for the cylindrical core mold, and laying up the pre-impregnated material sheet at least two angles of 0°, ±45°, 90° in combination layer by layer on the surface of the cylindrical core mold. During laying up, an axial tension of 5-10 N is applied to each pre-impregnated material sheet through a tension control system to ensure that the sheet is flat and wrinkle-free and that the fiber bundle is straightened;

[0021] 1b) After laying up, the core mold containing the pre-impregnated material is sealed as a whole with a vacuum bag, and then the vacuum bag is evacuated to ≤-0.09 MPa, and the pressure is maintained for 10-15 min to remove the air between the pre-impregnated material layers;

[0022] 1c) The sealed core mold is placed in a heat press tank as a whole to perform a staged curing process:

[0023] First, heat at 120-130°C and 0.3-0.5 MPa for 20-40 min to preliminarily crosslink the epoxy resin;

[0024] Then, heat to 140-150°C and increase the pressure to 0.6-0.8 MPa, and continue to heat for 10-50 min to completely cure the resin, with a total curing time of 30-90 min;

[0025] 1d) After curing, reduce the temperature of the heat press tank to room temperature at a rate of ≤5°C / min, then remove the vacuum bag and the core mold to obtain the molded carbon fiber composite material base shaft tube.

[0026] As a preferred, the following procedure is performed in step two:

[0027] 2a) The surface carboxyl content of the carboxylated multi-walled carbon nanotubes added in the nitrile rubber is ≥2wt%, and the mixture of the nitrile rubber and the carboxylated multi-walled carbon nanotubes is ultrasonically dispersed for 25-35 min at 400-600 W. The temperature of the modified rubber compound is controlled at 60-80°C during the dispersion process, so that the particle size of the carbon nanotube agglomerates is ≤5μm;

[0028] 2b) The inner surface of the base shaft tube is treated by plasma before the core is filled, the treatment power is 100-200 W, the time is 30-60 s, and the gas atmosphere is argon or oxygen;

[0029] 2c) The modified rubber compound is injected into the inner cavity of the base shaft tube through a double screw extruder, the injection pressure is 0.5-2 MPa, the barrel temperature is 80-100°C, the filling speed is 5-10 mm / s, and the vacuum degree is ≤-0.08 MPa through the vacuum suction device at both ends of the shaft tube to assist in exhausting the air;

[0030] 2d) After the modified rubber compound is filled into the inner cavity of the base shaft tube, the base shaft tube is left to stand at room temperature for 24 hours.

[0031] As preferred, step three is performed in the following procedure:

[0032] 3a) The same modified nitrile rubber as the filling core material is put into an open mill for plasticizing, the plasticizing time is controlled within 5-10 min, and the roller temperature is maintained at 50-70℃, then the roller gap of the open mill is adjusted to 1-2mm, and the rubber is processed into uniform sheets with a thickness of 1-3mm;

[0033] 3b) The metal mesh is a stainless steel mesh with a thickness of 0.1mm and a mesh number of 200-300, the metal mesh is first soaked in a 10% hydrochloric acid solution for 10-15min to remove the surface oxide layer, then washed with deionized water until neutral, and finally dried in an oven at 80-100℃, then the stainless steel mesh is cut into a rectangle matching the outer wall of the base shaft tube, and a puncture needle with a diameter of 0.5-1mm is used for puncture, with a puncture depth of 1 / 2-2 / 3 of the total thickness of the outer cover layer;

[0034] 3c) The modified rubber sheet processed and punctured is wound on the outer wall of the base shaft tube at a spiral angle of 30-60°, the overlapping width of adjacent sheets is 2-5mm, and the number of layers of the outer cover layer is 2-5, and the rubber roller is used to compact after each layer is laid;

[0035] 3d) The outer cover layer after winding and compaction is subjected to vulcanization treatment, the vulcanization time is 20-30min, and for every 1mm increase in the thickness of the outer cover layer, the vulcanization time is extended by 5min, and after vulcanization, it is naturally cooled to room temperature.

[0036] As preferred, in step four: the connecting flange is mechanically connected, the bolt tightening torque is , and the perpendicularity of the flange end face to the shaft axis after assembly is ≤0.1mm / m;

[0037] As preferred, before the prepreg is laid up, the cylindrical core mold is cleaned and coated with a release agent, and during the laying process, every 3-8 layers of prepreg laminates are laid up, the core mold is placed in a vacuum bag for vacuumizing, the vacuum degree is ≥0.09MPa, and the pressure is maintained for at least 30min to pre-compaction the 3-8 layers of prepreg interlayer and the core mold adhering surface.

[0038] As preferred, in the segmented curing process, the heating rate is controlled at 1-3℃ / min, and the cooling rate is ≤5℃ / min, and during the curing process, the pressure fluctuation is monitored by a pressure sensor, and the fluctuation amplitude is ±0.05MPa.

[0039] As preferably, the outer cladding layer is detected by ultrasonic flaw detection after vulcanization to detect internal defects, and no pore with a diameter of ≥1mm is required; the damping ratio in the frequency range of 10-500Hz is detected by a dynamic thermal mechanical analyzer, and the damping ratio is required to be ≥0.2; the thermal conductivity is detected by a laser thermal conductivity instrument, and the thermal conductivity is required to be .

[0040] As preferably, the high-damping transmission shaft is formed, and the whole is subjected to dynamic balance test, and the unbalance amount ; the fatigue test is carried out at a rotating speed of 1000-5000rpm, and the cycle number times without failure; the torque transmission efficiency is tested by a strain gauge, and the torque transmission efficiency is required to be ≥95%.

[0041] Compared with the prior art, the beneficial effects of the present application are:

[0042] 1. The present application realizes a breakthrough in the core performance of the transmission shaft through the dual-material synergistic design of the carbon nanotube modified rubber core layer and the metal mesh reinforced outer cladding layer. The carbon nanotube modified rubber core layer solves the contradiction between damping performance and thermal conductivity in traditional materials, and can efficiently absorb vibration energy to improve damping effect and build a rapid heat conduction network; the metal mesh reinforced outer cladding layer effectively balances the relationship between damping characteristics and structural strength, significantly improves the overall rigidity while ensuring the damping effect, and the two form a complementary function.

[0043] 2. The present application has significant performance optimization through the synergistic effect of dual materials: the core layer strengthens the damping energy dissipation and heat conduction capacity through carbon nanotube modification, and the generated heat can be rapidly diffused by the outer layer to avoid local heat accumulation affecting performance; the outer layer provides reliable mechanical protection by virtue of the metal mesh reinforced structure, effectively preventing the core layer from being damaged due to insufficient strength under stress or vibration, so that the damping performance and mechanical reliability form a virtuous cycle of mutual support, which is better than the use of single material or simple composite structure.

[0044] 3. The present application realizes a significant improvement in vibration attenuation effect through the synergistic effect of the carbon nanotube modified rubber core layer and the metal mesh reinforced outer cladding layer, and ensures the stability of the interface bonding and the fatigue resistance of the overall structure, and realizes the lightweight target through the optimization of material properties.

[0045] 4. The present application realizes the function complementation of the core layer and the outer layer, so that the transmission shaft can stably play a damping role under high vibration and high load working conditions, and can ensure the efficiency of power transmission and the long-term reliability of the structure, meeting the requirements of complex working conditions for transmission components. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The present application provides a cross-sectional view of a high-damping transmission shaft based on dual-material synergy.

[0047] In the figure: 1, base tube; 2, rubber core material; 3, rubber outer cladding layer; 4, connecting flange. DETAILED DESCRIPTION

[0048] The technical solutions of the present application will be described below in conjunction with specific examples. Obviously, the described examples are only some of the embodiments of the present application, not all. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0049] The structure of the transmission shaft prepared in each of the following examples is as shown (transmission shaft sectional view), wherein 1 is a base tube made of carbon fiber composite material, 2 is a rubber core material, 3 is a rubber outer cladding layer, and 4 is a connecting flange. Figure 1

[0050] Example 1

[0051] The process parameters and specific steps of the high-damping transmission shaft forming process based on double-material cooperation provided by the present embodiment are as follows:

[0052] Step one, preparation of base tube:

[0053] First, the pre-impregnated material has an epoxy resin mass ratio of 30%, which is cut into sheet materials suitable for the cylindrical core mold, and is combined and laid according to 0° and 90° angles, with an axial tension of 5N applied to each sheet.

[0054] Secondly, after the laying is completed, the vacuum bag is vacuumed to-0.09MPa, and the pressure is maintained for 10min; the segmented curing condition parameters of the autoclave are as follows: temperature 120℃, pressure 0.3MPa, holding for 20min, then increasing the temperature to 140℃, 0.6MPa, holding for 10min (total curing time 30min).

[0055] Finally, after the curing is completed, the temperature of the autoclave is reduced to room temperature at a rate of 5℃ / min, and after the temperature is stable, the vacuum bag and the cylindrical core mold are removed, and finally the carbon fiber composite material base tube 1 after molding is obtained.

[0056] Step two, core filling:

[0057] First, 3% carboxylated multi-walled carbon nanotubes (diameter 10nm, aspect ratio 50, surface carboxyl content 2wt%) are added to the nitrile rubber, ultrasonic dispersion is carried out at an ultrasonic power of 400W for 25min, the temperature is controlled at 60℃, and the particle size of the agglomerates is ensured to be ≤5μm.

[0058] ​Secondly, the inner cavity of the base shaft tube 1 is plasma treated: treatment power 100 W, treatment time 30 s, gas atmosphere argon atmosphere; the modified rubber is injected by a double screw extruder, the injection pressure is 0.5 MPa, the barrel temperature is 80 DEG C, the filling speed is 5 mm / s, and the shaft tube two ends are vacuumized to-0.08 MPa to assist exhaust.

[0059] Finally, after the modified rubber material is filled into the inner cavity of the base shaft tube 1, the base shaft tube 1 is placed at room temperature for 24 hours.

[0060] Step three, outer coating layer forming:

[0061] Firstly, the modified butyl rubber is put into the open mill, the plasticating time is 5 min, the roller temperature is kept at 50 DEG C, the open mill roller distance is adjusted to 1 mm, and the rubber is processed into 1 mm thick sheet.

[0062] Secondly, the stainless steel mesh (0.1 mm thick, 200 mesh) is soaked in 10% hydrochloric acid for 10 min, then washed to neutral, dried at a temperature of 80 DEG C, and cut into a rectangle matching the outer wall of the base shaft tube 1; a 0.5 mm diameter puncture needle is used, the puncture depth is 1 / 2 of the total thickness of the outer coating layer, and the puncture density is 50 per square centimeter.

[0063] Finally, the sheet is wound around the outer wall of the base shaft tube 1 with a spiral angle of 30 DEG, the overlapping width of adjacent sheets is 2 mm, the number of layers is 2, and each layer is compacted by a rubber roller; vulcanization conditions: vulcanization temperature 140 DEG C, vulcanization pressure 2 MPa, vulcanization time 20 min, and natural cooling to room temperature after vulcanization is completed.

[0064] Step four, connecting flange assembly:

[0065] The surface of the connecting flange 4 is sandblasted, and the carbon fiber base of the shaft assembly area is polished; then the positioning tool is used to ensure that the perpendicularity of the two is less than or equal to 0.1 mm / m, and the bolt tightening torque .

[0066] After ensuring the perpendicularity of the connecting flange 4 and the base shaft tube 1 by the positioning tool, the bolt is fastened to form a complete transmission shaft, the cross-sectional view of which is shown in Figure 1 , which is composed of the base shaft tube 1 made of carbon fiber composite material, the rubber core material 2 filled in the inner cavity, the rubber outer coating layer 3, and the connecting flange 4 assembled at both ends.

[0067] Performance detection:

[0068] Outer coating layer: no air hole greater than 1 mm, damping ratio 0.2 at 10 Hz frequency, thermal conductivity .

[0069] Overall performance: dynamic balance unbalance ; fatigue test at 1000 rpm speed Sub-failure; torque transmission efficiency 95%.

[0070] Embodiment 2:

[0071] The process parameters and specific steps of the high-damping transmission shaft forming process based on the dual-material cooperation provided in this embodiment are as follows:

[0072] Step one, preparing the base shaft tube:

[0073] First, the mass fraction of epoxy resin in the prepreg is 40%, and after cutting into sheets, it is combined and laid according to +45° and -45° angles, and 7.5N axial tension is applied to each sheet.

[0074] Secondly, after the laying is completed, the vacuum bag is vacuumed to-0.10MPa, and the pressure is maintained for 12min; the segmented curing condition parameters of the autoclave are: temperature 125℃, pressure 0.4MPa, holding for 30min, then increasing the temperature to 145℃, 0.7MPa, holding for 30min (total curing time 60min).

[0075] Finally, after the curing is completed, the temperature of the autoclave is reduced to room temperature at a rate of 3℃ / min, and after the temperature is stable, the vacuum bag and the cylindrical core mold are removed, and finally the molded carbon fiber composite base shaft tube 1 is obtained.

[0076] Step two, core filling:

[0077] First, add 4% carboxylated multi-walled carbon nanotubes (diameter 15nm, aspect ratio 75, surface carboxyl content 3wt%) to the nitrile rubber, ultrasonic dispersion for 30min under ultrasonic power 500W, control the temperature at 70℃, and ensure that the particle size of the agglomerates is ≤5μm.

[0078] Secondly, the inner cavity plasma treatment condition parameters of the base shaft tube 1 are: treatment power 150W, treatment time 45s, and gas atmosphere is oxygen atmosphere; the modified rubber is injected into the double screw extruder, the injection pressure is 1.2MPa, the barrel temperature is 90℃, the filling speed is 7.5mm / s, and the two ends of the shaft tube are vacuumed to-0.09MPa to assist exhaust.

[0079] Finally, after the modified rubber compound is filled into the inner cavity of the base shaft tube 1, the base shaft tube 1 is placed at room temperature for 24 hours.

[0080] Step three, outer cladding layer forming:

[0081] First, put the modified nitrile rubber into the open mill, plasticize for 7.5min, keep the roller temperature at 60℃, adjust the roller distance of the open mill to 1.5mm, and process the rubber into 2mm thick sheets.

[0082] Secondly, the stainless steel mesh (0.1 mm thick, 250 mesh) is soaked in 10% hydrochloric acid for 12 minutes, then washed with water to neutral, dried at a temperature of 90°C, and cut into a rectangle matching the outer wall of the base shaft tube 1; a 0.75 mm diameter puncture needle is used, with a puncture depth of 1 / 2~2 / 3 of the total thickness of the outer cladding layer, and a puncture density of 75 / cm².

[0083] Finally, the sheet is wound at a helix angle of 45° on the outer wall of the base shaft tube 1, with an overlapping width of 3.5 mm between adjacent sheets, and 3 layers of paving, each layer being compacted with a rubber roller; vulcanization conditions: vulcanization temperature 150°C, vulcanization pressure 2.5 MPa, vulcanization time 25 min, and natural cooling to room temperature after vulcanization is completed.

[0084] Step four, connecting flange assembly:

[0085] The connecting flange 4 is sandblasted on the surface, and the carbon fiber base is exposed by grinding the shaft assembly area, then the positioning tool is used to ensure that the perpendicularity of the two is ≤0.1 mm / m, and the bolt tightening torque is 30 N·m. Performance test:

[0086] Outer cladding layer: no ≥1 mm pores, damping ratio 0.3 at 250 Hz frequency, thermal conductivity .

[0087] Overall performance: dynamic balance unbalance ; 1.5×10 6 times fatigue test without failure at 3000 rpm speed; torque transmission efficiency 97%.

[0088] Example 3:

[0089] The process parameters and specific steps of the high-damping transmission shaft forming process based on double-material cooperation provided in this embodiment are as follows:

[0090] Step one, preparing the base shaft tube

[0091] First, the epoxy resin accounts for 50% of the mass of the prepreg, and after cutting into a sheet, it is combined and laid according to 0°, ±45° and 90° angles, and each sheet is subjected to an axial tension of 10 N.

[0092] Secondly, after the laying is completed, the vacuum bag is vacuumed to -0.12 MPa, and the pressure is maintained for 15 min; the segmented curing conditions of the autoclave are: temperature 130°C, pressure 0.5 MPa, holding for 40 min, then increasing the temperature to 150°C, 0.8 MPa, holding for 50 min (total curing time 90 min).

[0093] Finally, after the curing is completed, the temperature of the autoclave is decreased to room temperature at a rate of 5°C / min, and after the temperature is stabilized, the vacuum bag and the cylindrical core mold are removed, and finally the carbon fiber composite matrix shaft tube 1 after molding is obtained.

[0094] Step two, core filling:

[0095] First, 5% carboxylated multi-walled carbon nanotubes (diameter 20 nm, aspect ratio 100, surface carboxyl content 4 wt%) are added to the nitrile rubber, and ultrasonic dispersion is performed at an ultrasonic power of 600 W for 35 min, with the temperature controlled at 80°C, to ensure that the particle size of the agglomerates is ≤5 μm.

[0096] Second, plasma treatment of the inner cavity of the matrix shaft tube 1: treatment power 200 W, treatment time 60 s, gas atmosphere oxygen atmosphere; the modified rubber is injected by a double screw extruder, the injection pressure is 2 MPa, the barrel temperature is 100°C, the filling speed is 10 mm / s, and the shaft tube is vacuumed to -0.08 MPa at both ends to assist in exhaust.

[0097] Finally, after the modified rubber material is filled into the inner cavity of the matrix shaft tube 1, the matrix shaft tube 1 is left to stand at room temperature for 24 hours.

[0098] Step three, outer cover layer forming:

[0099] First, the modified nitrile rubber is put into the open mill, the plasticating time is 10 min, the roller temperature is kept at 70°C, the roller distance of the open mill is adjusted to 2 mm, and the rubber is processed into a 3 mm thick sheet.

[0100] Second, the stainless steel mesh (0.1 mm thick, 300 mesh) is soaked in 10% hydrochloric acid for 15 min, then washed with water until neutral, dried at a temperature of 100°C, and then cut into a rectangle matching the outer wall of the matrix shaft tube 1; a 1 mm diameter puncture needle is used, the puncture depth is 2 / 3 of the total thickness of the outer cover layer, and the puncture density is 100 / cm².

[0101] Finally, the sheet is wound around the outer wall of the matrix shaft tube 1 at a spiral angle of 60°, the overlap width of adjacent sheets is 5 mm, the number of layers of wrapping is 5, and each layer is compacted with a rubber roller; vulcanization conditions: vulcanization temperature 160°C, vulcanization pressure 3 MPa, vulcanization time 35 min (because the sheet thickness is 3 mm, compared with the sheet thickness of 2 mm, the time is extended by 5 min), and the vulcanization is naturally cooled to room temperature after completion.

[0102] Step four, connecting flange assembly:

[0103] The surface of the connecting flange 4 is sandblasted, and the carbon fiber matrix is exposed by grinding the shaft assembly area; then the positioning tool is used to ensure the perpendicularity of the two , the tightening torque of the bolt .

[0104] Performance test:

[0105] Outer cover: no >1mm air hole, damping ratio 0.4 at 500Hz frequency, thermal conductivity 0.9 W / (m·K).

[0106] Overall performance: dynamic balance unbalance ; fatigue test at 5000rpm speed Sub-failure; torque transmission efficiency 99%.

[0107] Comparative Example 1:

[0108] This comparative example does not add carboxylated multi-walled carbon nanotubes, and the rest of the process parameters are consistent with Example 2, and the specific differences are as follows:

[0109] 1. Core filling: directly use unmodified nitrile rubber, omit the ultrasonic dispersion step, and the rest of the filling process (plasma treatment, extruder parameters, etc.) is the same as Example 2.

[0110] 2. Outer cover forming: use unmodified nitrile rubber to prepare a sheet, and the rest of the steps are the same as Example 2.

[0111] 3. Performance difference estimation:

[0112] Core material and shaft tube inner cavity interface peeling strength decreases (Example 2 is 6kN / m);

[0113] Outer cover damping ratio decreases at 10-500Hz frequency (Example 2 is 0.3);

[0114] 1000-5000rpm fatigue test cycle number decreases (Example 2 is Sub-failure).

[0115] Comparative Example 2:

[0116] This comparative example does not pre-compact during the base shaft tube layering process, and the rest of the process parameters are consistent with Example 2, and the specific differences are as follows:

[0117] 1. Prepare the base shaft tube: directly continuously lay to the designed number of layers during layering (without using the method of pre-compact every 3-8 layers), and the rest of the curing parameters are the same as Example 2.

[0118] 2. Performance difference estimation:

[0119] Base shaft tube interlayer porosity increases (Example 2 is ≤1%);

[0120] Torque transmission efficiency decreases (Example 2 is 97%);

[0121] Dynamic balance unbalance increases (Example 2 is ).

[0122] Comparative Example 3:

[0123] The comparative example omits the metal mesh embedding step, and the rest of the process parameters are consistent with Example 2, with the specific differences as follows:

[0124] 1. Outer cover layer forming: The rubber sheet is directly wound around the outer wall of the shaft tube, without embedding the stainless steel mesh, and the puncture and vulcanization parameters are the same as in Example 2.

[0125] 2. Performance difference estimation:

[0126] The tear resistance of the outer cover layer decreases (Example 2 is 30 kN / m);

[0127] The thermal conductivity decreases (Example 2 is );

[0128] The vibration amplitude increases at a speed of 5000 rpm (Example 2 is stable in vibration).

[0129] In order to verify the performance differences between Examples 1-3 and Comparative Examples 1-3, the following test methods are used in the present application:

[0130] I. Damping ratio test:

[0131] 1. Sample preparation: Cut a 10mm x 50mm x 2mm sample from the outer cover layer of the transmission shaft (ensure that it contains the metal mesh and rubber composite structure).

[0132] 2. Test equipment: Dynamic mechanical analyzer (DMA).

[0133] 3. Test parameters: Temperature 25℃, frequency range 10-500Hz, amplitude 0.1%, heating rate 5℃ / min.

[0134] 4. Calculation method: Record the loss factor (tan δ) of DMA, i.e. the damping ratio, and take the minimum value in the range of 10-500Hz as the result.

[0135] The experimental data of damping performance are as follows:

[0136]

[0137] Data description: the vibration attenuation rate is also accelerated, so that the vibration noise in the operation of the equipment can be reduced more efficiently. In the embodiment of the application, the damping performance advantage of the transmission shaft is derived from the following two aspects: on the one hand, 3%-5% carboxylated multi-walled carbon nanotubes (diameter 10-20 nm, aspect ratio 50-100) added in the nitrile rubber are uniformly dispersed in the rubber matrix after 400W-600W ultrasonic dispersion, the high specific surface area of the carbon nanotubes and the surface carboxyl groups can enhance the friction energy consumption of the rubber molecular chain through the interfacial action, and significantly improve the damping properties of the rubber material itself; on the other hand, the 200-300 mesh stainless steel mesh embedded in the outer cladding layer is combined with the puncture-vulcanization process (puncture density , vulcanization temperature 140℃-160℃), the metal mesh not only provides structural support for the rubber layer and reduces the deformation loss in the vibration process, but also further dissipates vibration energy through the synergistic deformation of the mesh skeleton and the rubber matrix, forming a double damping mechanism.

[0138] On the contrary, the comparative examples lack the above-mentioned synergistic enhancement effect due to the absence of carbon nanotubes (comparative example 1), the absence of metal mesh (comparative example 3) or the omission of the key process (comparative example 2), resulting in a generally lower damping ratio of 0.18, a vibration attenuation rate of only 50%-70% of the embodiment, and a significantly inferior vibration damping performance to the embodiment, verifying the key advantage of the carbon nanotube modification and metal mesh enhancement technology in the application in improving the damping performance.

[0139] II. Interfacial peel strength test:

[0140] 1. Sample preparation: cut the interface sample containing the matrix shaft tube-core material or the matrix shaft tube-outer cladding layer along the axis direction of the transmission shaft, with a size of 100mm×25mm×5mm (interface width 25mm).

[0141] 2. Test equipment: universal material testing machine.

[0142] 3. Test parameters: tensile speed 50mm / min, ambient temperature 25℃.

[0143] 4. Calculation method: peel strength = maximum peeling force (N) / interface width (m), taking the average value of 3 parallel tests.

[0144] The interfacial peel strength experimental data are as follows:

[0145]

[0146] Data Description: Peel strength is a core indicator to measure the bonding strength of different material interfaces. The higher the value, the stronger the interfacial adhesion, and the more prominent the resistance to external force peeling. The lower the interface defect rate (such as bubbles, gaps, etc.), the closer the contact between materials, the more uniform the stress distribution, and the more excellent the interface stability under long-term stress or vibration conditions.

[0147] In the embodiments of the present application, the advantages of interfacial bonding performance are derived from the synergistic effect of multi-dimensional process design: for the interface between the base shaft tube and the core material, before filling, a plasma treatment (30s-60s, argon / oxygen atmosphere) with a power of 100W-200W is used to clean the surface and introduce active groups through high-energy particle bombardment, which improves the compatibility of carbon fiber composite materials and modified rubber. At the same time, a double-screw extruder is used for injection, and vacuum suction (vacuum degree ≤-0.08MPa) is applied at both ends of the shaft tube to effectively remove air from the interface to reduce bubbles, making the peel strength stable at more than 5kN / m, and the defect rate ≤0.8%; for the interface between the base shaft tube and the outer coating layer, the modified rubber sheet is wound at a spiral angle of 30°-60° and compacted, and after vulcanization at 140℃-160℃ and 2MPa-3MPa, the chemical bonding and physical embedding of rubber and carbon fiber are promoted, and the skeleton of the metal mesh is added to enhance the peel strength to more than 6.5kN / m, and the defect rate is almost zero. In contrast, the comparative examples omit key processes (such as comparative example 1 without carbon nanotube modification, comparative example 2 without pre-compaction, and comparative example 3 without embedding metal mesh), resulting in poor interfacial compatibility and insufficient mechanical engagement, with peel strength generally below 4.5kN / m and defect rate of 2.5%-4.1%, which is prone to delamination and peeling due to vibration during long-term use.

[0148] III. Fatigue Performance Test:

[0149] 1. Sample Preparation: Complete transmission shaft (including connecting flange).

[0150] 2. Test Equipment: Transmission shaft fatigue test bench.

[0151] 3. Test Parameters: Rotational speed 1000-5000rpm (continuous increase), 1.2 times the rated torque is applied, and the environmental temperature is 25℃.

[0152] 4. Judgment Criteria: Record the number of cycles when cracks, deformation, or a decrease in torque transmission efficiency ≥10% occur in the transmission shaft, which is the fatigue life.

[0153] Fatigue performance test experimental data:

[0154]

[0155] Data Description: Fatigue cycle number is a key indicator to evaluate the anti-failure ability of the transmission shaft under alternating load. The more the cycle number is, the later the failure occurs, indicating that the structure has stronger stability under long-term dynamic stress and longer fatigue life. This indicator directly reflects the durability of the transmission shaft under actual working conditions (such as 1000-5000 rpm speed fluctuation), and is a core parameter to measure its reliability.

[0156] In the embodiments of the present application, on the one hand, during the laying process of the carbon fiber prepreg, every 3-8 layers are pre-compacted by ≥0.09 MPa vacuum for more than 30 min, and then are subjected to sectional curing (120℃-150℃, 0.3 MPa-0.8 MPa) in a hot press tank, so as to effectively reduce the interlayer porosity (porosity ≤1%) and make the fiber-resin interface of the matrix shaft tube more closely combined, thereby significantly improving the anti-fatigue cracking ability. On the other hand, the 200-300 mesh stainless steel mesh embedded in the outer cladding layer forms a composite structure with the modified rubber. The metal mesh disperses the vibration stress through the skeleton effect, avoiding early tearing caused by local stress concentration, while the carbon nanotube modified rubber absorbs fatigue energy through the elastic deformation of molecular chains, delaying crack propagation. The double reinforcement makes the fatigue cycle number of the embodiments under 1000-5000 rpm speed reach more than times, and some embodiments even exceed times.

[0157] On the contrary, in the comparative examples, the pre-compaction is omitted in Comparative Example 2, the interlayer porosity of the matrix shaft tube increases to 5%, which becomes the initiation point of fatigue cracks; the metal mesh is not embedded in Comparative Example 3, and the anti-deformation ability of the outer cladding layer is insufficient, which is easy to fall off under high-frequency vibration; and the rubber is not modified in Comparative Example 1, the damping energy consumption is insufficient, and the interface is peeled off in advance due to the continuous accumulation of stress, so that the fatigue cycle number is less than times.

[0158] Four, torque transmission efficiency test

[0159] 1. Sample preparation: complete transmission shaft (including input / output end flanges).

[0160] 2. Test equipment: torque sensor (accuracy ±0.5%), tachometer.

[0161] 3. Test parameters: input speed 1000 rpm, gradually loaded to 80% of the rated torque, and stably run for 30 min.

[0162] 4. Calculation method: torque transmission efficiency = (output torque × output speed) / (input torque × input speed) × 100%, taking the average of 3 measurements.

[0163] The experimental data of the torque transmission efficiency are as follows:

[0164]

[0165] Data description: Torque transmission efficiency is a core indicator to measure the power transmission capacity of the transmission shaft. The higher the efficiency, the less the loss of input power, and the more sufficient the energy utilization. The smaller the torque fluctuation, the more stable the force transmission in the transmission process, which can reduce the vibration and noise caused by instantaneous load mutation, and is a key parameter to evaluate the stability of the transmission system. Both of them reflect the power transmission performance of the transmission shaft under actual working conditions.

[0166] In the embodiment of the application, on the one hand, the carbon fiber prepreg is stretched straight by 5-10N axial tension during the laying of the carbon fiber prepreg, and each 3-8 layers are pre-pressed by ≥0.09MPa vacuum to cooperate with the segmented curing of the autoclave (pressure fluctuation ±0.05MPa), so that the matrix shaft pipe layers are tightly fitted and the porosity is ≤1%, thereby avoiding the power loss caused by interlayer slip; on the other hand, the perpendicularity is ensured to be ≤0.1mm / m by positioning tooling during the assembly of the connecting flange, and the bolts are uniformly tightened according to the torque of 10-50N·m, thereby reducing the additional resistance caused by assembly deviation, and the metal mesh reinforcing structure of the outer cladding layer improves the overall rigidity, thereby avoiding the torque fluctuation caused by deformation during high-speed rotation. Multiple optimization makes the torque transmission efficiency of the embodiment ≥95% and the fluctuation amplitude ≤1.2%. In contrast, the transmission performance of the comparative examples is reduced due to process defects: in comparative example 2, the pre-pressing is omitted, there are a large number of pores between the matrix shaft pipe layers, the fiber and the resin have weak cooperative stress resistance, and interlayer slip occurs during power transmission, so that the efficiency is reduced to 90%; in comparative examples 1 and 3, the interface bonding is poor (the rubber is not modified or there is no metal mesh), and the interface friction is intensified during high-speed rotation, so that not only the efficiency is obviously lost, but also the torque fluctuation amplitude is increased to more than 2.5%.

[0167] V. Dynamic balance test:

[0168] 1. Sample preparation: complete transmission shaft (including flange).

[0169] 2. Test equipment: hard support dynamic balancing machine.

[0170] 3. Test parameters: rotating speed 1500rpm, balance accuracy grade G6.3.

[0171] 4. Calculation method: unbalance = (balancing machine measurement value x correction radius) / transmission shaft mass, unit: .

[0172] VI. Thermal conductivity test:

[0173] 1. Sample preparation: cut 50mm×50mm×3mm sample from the outer cladding layer.

[0174] 2. Test equipment: laser thermal conductivity instrument.

[0175] 3. Test parameters: temperature 25℃, heat flow direction perpendicular to the surface of the coating layer.

[0176] 4. Calculation method: calculate the thermal conductivity according to Fourier's law , where Q is the heat flux density, d is the sample thickness, A is the test area, and ΔT is the temperature difference.

[0177] Seven, porosity detection:

[0178] 1. Sample preparation: after vulcanization of the outer coating layer, cut the cross-section sample, and polish it.

[0179] 2. Test equipment: ultrasonic flaw detector (probe frequency 5MHz).

[0180] 3. Test parameters: flaw detection sensitivity flat-bottomed hole, the scanning range covers the entire coating layer area.

[0181] 4. Judgment standard: record the number of pores with a diameter ≥1mm, and if there is no such pore, it is qualified.

[0182] Note: all tests need to be tested in triplicate, if the single result deviates from the average value ≤10%, take the average value as the final data; if the deviation >10%, retest and exclude abnormal values.

[0183] The main performance experimental data of the above examples and comparative examples are compared as follows:

[0184]

[0185] Experimental data analysis:

[0186] The advantages of the high-damping transmission shaft forming process based on the cooperation of the double materials of the present application compared with the existing process are: the damping ratio of examples 1-3 is 0.2-0.4 (10-500Hz frequency range), which is significantly higher than that of the comparative example (0.12-0.18), which indicates that the modification of carboxylated multi-walled carbon nanotubes (3%-5%) to nitrile rubber, and the embedding and puncture-vulcanization process of 200-300 mesh stainless steel mesh in the outer coating layer (puncture density) , forms a double damping mechanism of molecular level energy consumption and structural level energy consumption, the high specific surface area of carbon nanotubes enhances the friction energy consumption of rubber molecular chain, and the metal mesh further dissipates vibration energy through skeleton cooperative deformation, so that the vibration attenuation rate (8.5-10.1dB / s) of the examples is more than 50% higher than that of the comparative example (4.8-6.1dB / s), effectively solving the problem of insufficient damping of traditional transmission shafts.

[0187] The interface peel strength of the embodiment is 5-8 kN / m, and the interface defect rate is ≤0.8%, which is much better than the comparative example (peel strength 3-4.5 kN / m, defect rate 2.5%-4.1%), and the core reason is that the active groups are introduced into the inner cavity of the matrix shaft tube by 100 W-200 W plasma treatment, and the compatibility of rubber and carbon fiber is improved by vacuum assisted filling (≤-0.08 MPa) to eliminate bubbles, and the outer cladding layer is wrapped with 30°-60° spiral and vulcanized (140℃-160℃, 2 MPa-3 MPa), which strengthens the physical embedding and chemical bonding, and the mechanical engagement force of the metal mesh is added, which avoids the interface peeling problem caused by the process omission of the comparative example.

[0188] The fatigue cycle number of the embodiment at 1000-5000 rpm times is 1.25-2 times that of the comparative example (times) , which is due to the pre-compaction (≥0.09 MPa) and segmented curing process of the carbon fiber prepreg every 3-8 layers, which makes the interlayer porosity of the matrix shaft tube ≤1%, the fiber-resin synergistic stress capacity is enhanced, and the metal mesh disperses the vibration stress, the modified rubber absorbs the fatigue energy through elastic deformation, and delays the crack propagation, while the comparative example omits the pre-compaction (interlayer porosity 5%) and metal mesh, which leads to the early failure of the weak structure part; the torque transmission efficiency of the embodiment is ≥95%, and the fluctuation amplitude is ≤1.2%.

[0189] In addition, the weight of the transmission shaft prepared by the embodiment is reduced by 30%-40% compared with the comparative example 2 (steel shaft typical value), and the advantage is that the pre-compaction and segmented curing ensure the density of the matrix shaft tube, reduce the interlayer slip loss, and the flange assembly reduces the additional resistance through positioning tooling (perpendicularity ≤0.1 mm / m) and precise torque control (0.1-0.5 Nm) ).

[0190] On the contrary, the efficiency loss of the comparative example is 3%-7% due to interlayer defects or interface failure, and the torque fluctuation is 2.5%-3.1%, which verifies the improvement of the process of the embodiment on the stability of the transmission; the outer cladding layer of the embodiment is detected by ultrasonic flaw detection without ≥1 mm pores, while the comparative example has a pore rate of 1.2%-5.0% due to the process defects such as unmodified rubber and unpre-compacted, which shows that the present application effectively guarantees the stability of product quality by fine process such as ultrasonic dispersion (400 W-600 W) to control the particle size of carbon nanotube agglomerates ≤5 μm and pre-compaction to exclude interlayer air.

[0191] In summary, the experimental data fully prove that the present application realizes the performance improvement of high damping, strong interface, long service life and high transmission efficiency of the transmission shaft, and all performance indicators are significantly better than the comparative example which lacks core process.

[0192] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A high-damping drive shaft forming process based on dual-material synergy, characterized in that, The drive shaft is made of carbon fiber composite material for its base tube. The inner cavity of the base tube is filled with rubber, and the outer wall of the base tube is covered with rubber to form an outer wrapping layer. The process specifically includes the following steps: Step 1: Preparation of the base shaft tube The carbon fiber composite material is a prepreg composed of carbon fiber and epoxy resin, and the matrix tube is prepared by prepreg layup and segmented curing process. The epoxy resin in the prepreg accounts for 30%-50% by mass, the curing temperature of the prepreg is 120℃-150℃, and the curing pressure is 0.3MPa-0.8MPa. Step 2: Core Filling The rubber is a modified nitrile butadiene rubber, in which 3%-5% by mass of carboxylated multi-walled carbon nanotubes are added to the nitrile butadiene rubber to form the modified nitrile butadiene rubber. The carboxylated multi-walled carbon nanotubes have a diameter of 10-20 nm and an aspect ratio of 50-100. The modified nitrile rubber is filled into the inner cavity of the matrix tube after being ultrasonically dispersed. Step 3: Forming the outer coating layer The modified nitrile rubber treated by ultrasonic dispersion in step two is made into a rubber sheet. A metal mesh is embedded in the rubber sheet. The rubber sheet with embedded metal mesh is then treated by a puncture-vulcanization process to form an outer coating layer. This outer coating layer is then wrapped around the outer wall of the base shaft tube to obtain the drive shaft body. During the puncture-vulcanization process, the puncture density of the rubber sheet with embedded metal mesh is 50-100 punctures / cm², the vulcanization temperature is 140℃-160℃, and the vulcanization pressure is 2MPa-3MPa. Step 4: Connecting flange assembly First, the surface of the connecting flange is sandblasted to enhance the fit, and the assembly area of ​​the drive shaft body is polished to expose the carbon fiber matrix layer. After calibrating the perpendicularity between the connecting flange and the drive shaft body using positioning fixtures, the bolts are finally tightened to assemble the connecting flange and the drive shaft body into one unit.

2. The process according to claim 1, characterized in that, Perform step one according to the following procedures: 1a) The prepreg composed of carbon fiber and epoxy resin is cut into prepreg sheets that fit the cylindrical mandrel. The prepreg sheets are laid layer by layer on the surface of the cylindrical mandrel at at least two of the following angles: 0°, ±45°, and 90°. During the layup, an axial tension of 5-10N is applied to each prepreg sheet through a tension control system to ensure that the sheet is flat and wrinkle-free and the fiber bundles are straight. 1b) After the prepreg is laid, seal the core mold containing the prepreg with a vacuum bag, then evacuate the vacuum bag to ≤-0.09MPa and hold the pressure for 10-15 minutes to remove the air between the prepreg layers; 1c) Place the sealed core mold in an autoclave for a segmented curing process: First, keep the epoxy resin at 120℃-130℃ and 0.3MPa-0.5MPa pressure for 20-40 minutes to allow it to undergo initial cross-linking. Then raise the temperature to 140℃-150℃ and the pressure to 0.6MPa-0.8MPa, and continue to hold the temperature for 10-50 minutes to achieve complete resin curing. The total curing time is 30-90 minutes. 1d) After curing, the temperature of the autoclave is reduced to room temperature at a rate of ≤5℃ / min. Then the vacuum bag and mandrel are removed to obtain the molded carbon fiber composite matrix tube.

3. The process according to claim 1, characterized in that, Perform step two according to the following procedures: 2a) The surface carboxyl content of the carboxylated multi-walled carbon nanotubes added to the nitrile rubber is ≥2wt%. The mixture of nitrile rubber and carboxylated multi-walled carbon nanotubes is ultrasonically dispersed at 400W-600W for 25min-35min. During the dispersion process, the temperature of the modified rubber compound is controlled at 60℃-80℃ so that the particle size of the carbon nanotube aggregates is ≤5μm. 2b) Before filling the core material, the inner surface of the matrix shaft tube is subjected to plasma treatment with a power of 100W-200W and a time of 30s-60s. The gas atmosphere is argon or oxygen. 2c) The modified rubber compound is injected into the inner cavity of the matrix tube through a twin-screw extruder. The injection pressure is 0.5MPa-2MPa, the barrel temperature is 80℃-100℃, and the filling speed is 5-10mm / s. At the same time, the vacuum suction device at both ends of the shaft tube is used to draw a vacuum to assist in exhausting the air. The vacuum degree is ≤-0.08MPa. 2d) After the modified rubber compound is filled into the inner cavity of the matrix shaft tube, the matrix shaft tube is left to stand at room temperature for 24 hours.

4. The process according to claim 1, characterized in that, Perform step three according to the following procedures: 3a) Put the same modified nitrile rubber as the core material into the open mill for plasticizing. The plasticizing time is controlled at 5-10 minutes and the roll temperature is maintained at 50℃-70℃. Then adjust the roll gap of the open mill to 1-2 mm and process the rubber into uniform sheets with a thickness of 1 mm-3 mm. 3b) The metal mesh is a stainless steel mesh with a thickness of 0.1 mm and a mesh count of 200-300. Before use, the metal mesh is soaked in a 10% hydrochloric acid solution for 10-15 minutes to remove the surface oxide layer, then rinsed with deionized water until neutral, and finally dried in an oven at 80℃-100℃. The stainless steel mesh is then cut into a rectangle that matches the outer wall of the substrate tube. When piercing, a piercing needle with a diameter of 0.5 mm-1 mm is used, and the piercing depth is 1 / 2-2 / 3 of the total thickness of the outer coating layer. 3c) The modified rubber sheet that has been processed and punctured is wound around the outer wall of the base tube at a spiral angle of 30°-60°. The overlap width of adjacent sheets is 2mm-5mm, and the number of layers is 2-5. After each layer is laid, it is compacted with a rubber roller. 3d) The outer coating layer after winding and compaction is subjected to vulcanization treatment. The vulcanization time is 20min-30min. For every 1mm increase in the thickness of the outer coating layer, the vulcanization time is extended by 5min. After vulcanization, it is naturally cooled to room temperature.

5. The process according to claim 1, characterized in that, In step four: the connecting flange is mechanically connected, and the bolt tightening torque is... After assembly, the perpendicularity between the flange end face and the shaft axis is ≤0.1mm / m.

6. The process according to claim 2, characterized in that, Before laying the prepreg, the cylindrical core mold is cleaned and coated with a release agent. During the laying process, every 3-8 layers of prepreg are laid, the core mold is placed in a vacuum bag and vacuumed to a vacuum degree ≥0.09MPa. The pressure is maintained for at least 30 minutes to precompact the interlayer and the surface of the prepreg that is in contact with the core mold.

7. The process according to claim 2, characterized in that, In the segmented curing process, the heating rate is controlled at 1℃ / min-3℃ / min, the cooling rate is ≤5℃ / min, and the pressure fluctuation is monitored by a pressure sensor during the curing process, with a fluctuation range of ±0.05MPa.

8. The process according to claim 4, characterized in that, After the outer coating is vulcanized, internal defects are detected using ultrasonic testing, requiring the absence of pores with a diameter ≥1mm; the damping ratio is measured using a dynamic thermomechanical analyzer within a frequency range of 10-500Hz, requiring a damping ratio ≥0.2; and the thermal conductivity is measured using a laser thermal conductivity meter, requiring a thermal conductivity of ≥0.

2. .

9. The process according to claim 5, characterized in that, After the high-damping drive shaft is formed, the whole structure undergoes a dynamic balancing test to determine the imbalance amount. Fatigue tests were conducted at speeds of 1000-5000 rpm, with a cycle count of [number missing]. No failures were observed; torque transmission efficiency was tested using strain gauges, and the torque transmission efficiency was required to be ≥95%.

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