Flexible heat-insulating wear-resistant ring and preparation method and application thereof

Abstract

The application discloses a flexible heat-insulating wear-resistant ring, comprising a three-layer functional gradient composite structure, wherein the inner layer is a ceramic fiber reinforced silicone rubber layer, the middle layer is an aramid fiber woven layer, and the outer layer is a polyurethane-graphene composite material layer; the ceramic fiber reinforced silicone rubber layer is obtained by cross-linking and compounding of raw silicone rubber, ceramic fiber and a ceramic thermal stabilizer as main raw materials; and the surface of the polyurethane-graphene composite material layer is provided with a micro-groove structure. The flexible heat-insulating wear-resistant ring can effectively block heat conduction, disperse frictional stress and optimize a heat dissipation path, so that the working temperature is significantly reduced, the abrasion is reduced, the service life of equipment is prolonged, the reliability and construction efficiency of the vibration rod under severe working conditions such as high temperature and high abrasion are improved, and the applicability is wide.

Description

Technical Field

[0001] This invention belongs to the technical field of concrete construction equipment, specifically relating to a flexible heat-insulating and wear-resistant ring, its preparation method, and its application. Background Technology

[0002] A concrete vibrator is a specialized tool used for compacting concrete. It uses high-frequency vibration to compact the concrete, eliminating air bubbles and honeycomb-like defects, thereby increasing strength and ensuring component quality. When the vibrator is working, it directly transfers vibrational energy to the concrete, breaking down the cohesion of the cement paste, causing air bubbles to escape, and simultaneously rearranging the concrete particles through vibration to form a dense structure.

[0003] In existing concrete vibrator technologies, flexible tube structures generally suffer from heat accumulation and wear problems. Patent CN222391021U discloses a low-noise vibrator, which effectively reduces noise pollution through vacuum tube technology, but its vacuum-sealed structure increases maintenance costs and fails to fundamentally solve the problem of heat generation from friction between the flexible shaft and the steel belt. Patent CN222178129U proposes a composite vibration technology that improves vibration efficiency through multi-directional vibration, but its complex mechanical structure not only increases equipment weight but also exacerbates heat accumulation inside the flexible tube, leading to faster aging of key components. Patent CN202882444U uses a surface textured design to improve vibration efficiency, but this structure suffers severe wear after long-term use, affecting vibration performance and causing further temperature increases inside the flexible tube due to increased friction. The above solutions focus on optimizing a single performance aspect while neglecting overall thermal management, or suffer from excessive costs due to structural complexity. None of these solutions fundamentally solve the reliability problem of concrete vibrators under high-temperature conditions, severely restricting construction efficiency and service life. The construction engineering field urgently needs a vibratory rod solution that can effectively dissipate heat while maintaining high performance. Summary of the Invention

[0004] The main objective of this invention is to address the problems of frictional heat generation, wear, and insufficient thermal management in existing concrete vibrators by providing a flexible heat-insulating and wear-resistant ring for concrete vibrators and its application. By setting a flexible heat-insulating and wear-resistant ring with a specific composite structure between the flexible shaft and the steel belt, heat conduction is effectively blocked, frictional stress is dispersed, and heat dissipation path is optimized, thereby significantly reducing the operating temperature, reducing wear, extending the service life of the equipment, and improving the reliability and construction efficiency of the vibrator under harsh conditions such as high temperature and high wear.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A flexible heat-insulating and wear-resistant ring comprises a three-layer functionally graded composite structure, wherein the inner layer is a ceramic fiber reinforced silicone rubber layer, the middle layer is an aramid fiber braided layer, and the outer layer is a polyurethane-graphene composite material layer; the ceramic fiber reinforced silicone rubber layer is obtained by cross-linking and compounding silicone rubber raw rubber, ceramic fiber and ceramic heat stabilizer as the main raw materials; the surface of the polyurethane-graphene composite material layer is provided with a microgroove structure.

[0006] Furthermore, the thickness ratio of the inner layer, middle layer, and outer layer is 7:3~4:2~4.

[0007] In the above scheme, the thickness of the ceramic fiber reinforced silicone rubber layer is preferably 0.80-0.90 mm, more preferably 0.82-0.86 mm, and the thermal resistance value is 0.85-0.90 K / W, which can effectively reduce the surface temperature of the flexible shaft.

[0008] Furthermore, the ceramic heat stabilizer may be selected from one or more of nano-alumina, boron nitride particles, etc.; its dosage accounts for 10-15 wt% of the total mass of the ceramic fiber reinforced silicone rubber layer, so as to enhance the thermal stability and structural integrity of the material under extreme temperatures.

[0009] Furthermore, the ceramic fiber is selected from at least one of alumina fiber, aluminum silicate fiber, mullite fiber, etc.; the fiber diameter is 5-15μm and the length is 50-200μm; its mass percentage in the ceramic fiber reinforced silicone rubber layer is 20-30wt%.

[0010] Furthermore, the specific preparation steps of the ceramic fiber reinforced silicone rubber layer include the following steps: S1. Ingredients: By weight, weigh 100 parts of methyl vinyl silicone rubber raw rubber, 25-35 parts of ceramic fiber, 10-15 parts of ceramic heat stabilizer (nano alumina or boron nitride particles), 5-8 parts of fumed silica, 2.0-2.5 parts of crosslinking agent (such as dicumyl peroxide DCP, etc.) and 0.5-1.0 parts of silane coupling agent; S2. Pretreatment: The weighed ceramic fibers are heat-treated at 750-800℃ for 2-3 hours, and then surface-modified using an alcohol solution of silane coupling agent (solvent such as ethanol); S3. Mixing: Place the raw methyl vinyl silicone rubber on a two-roll mill and plasticize (3-5 minutes). Add fumed silica, pretreated ceramic fiber, and ceramic heat stabilizer in sequence. Pass through the mill 10-15 times under the conditions of a roll temperature of 40-60℃ and a roll gap of 0.5-1.0mm. S4. Crosslinking: Add crosslinking agent and continue mixing (roller temperature 40-60℃, roller gap 0.5-1.0mm) until evenly dispersed (5-8 minutes) to obtain the compound; S5. Molding and vulcanization: The obtained compound is coated on the surface of the substrate and molded at a temperature of 165-175℃ and a pressure of 10-15MPa (15-20 minutes). After demolding, it is vulcanized again at 170-200℃ for 2-4 hours to obtain the ceramic fiber reinforced silicone rubber layer.

[0011] In the above scheme, the thickness of the aramid fiber braided layer is 0.34-0.50 mm; the braiding angle is 55-65°; and the braiding density is 85-95%.

[0012] Furthermore, the preparation method of the aramid fiber braided layer includes the following steps: T1. Raw material selection and pretreatment: Para-aramid fiber filaments with a linear density of 1500-2000 dtex (preferably 1660-1680 dtex) and a breaking strength of not less than 23 cN / dtex are selected as raw materials; the aramid filaments are immersed in a surface treatment agent at 70-80℃ for 5-10 minutes; after removal, they are dried (120±5℃) to enhance the interfacial bonding force between the fiber and the resin; T2. Braiding: The pretreated aramid filaments are braided in groups of 16 to 18 strands on a high-speed braiding machine using a 2 / 2 twill braiding process, with the braiding angle controlled at 55°-65° and the braiding density at 85-95%, to obtain aramid fiber braided sleeves. T3. Setting and post-treatment: The braided sleeve is placed in a heat setting device and heat-set at a temperature of 240-260℃ and a pretension of 5-10N (30-60 seconds), and then naturally cooled to obtain an aramid fiber braided layer.

[0013] In the above scheme, the surface treatment agent includes, but is not limited to, one or more of silane coupling agents, epoxy resin emulsions, and polyurethane treatment agents.

[0014] In the above scheme, the thickness of the polyurethane-graphene composite material layer is 0.22-0.50 mm.

[0015] Furthermore, the polyurethane-graphene composite material layer is obtained by combining thermoplastic polyurethane elastomer and carboxyl-modified graphene as the main raw materials.

[0016] Furthermore, the mass ratio of the thermoplastic polyurethane elastomer to the carboxyl-modified graphene is 100:5-8.

[0017] Furthermore, the preparation method of the polyurethane-graphene composite material layer specifically includes the following steps: U1. Preparation of composite material: Dissolve 100 parts by weight of thermoplastic polyurethane elastomer in 400-500 parts of organic solvent (N,N-dimethylformamide DMF, etc.) and stir until completely dissolved; add 5-8 parts of carboxyl-modified graphene and 1-2 parts of dispersant (BYK-163, etc.) and perform high-speed shear emulsification (disperse at 6000-8000 r / min for 30-40 minutes) to form a uniform dispersion; U2. Molding and processing: The obtained dispersion is cast onto a flat substrate and dried (90-100℃) to remove the solvent, resulting in a composite film; U3. Surface structuring and functionalization: The designed groove structure is prepared on the surface of the composite film by laser micromachining process; then, the film is immersed in a dispersion of graphene microspheres with a concentration of 0.5-3.0 mg / mL (graphene microsphere particle size 50-80 nm), or the graphene microsphere dispersion is applied to the surface and interior of the groove by spraying or spin coating. After drying, the graphene microspheres are embedded and attached to the groove to form a self-lubricating surface.

[0018] In the above scheme, the particle size of the graphene microspheres is 50-80 nm.

[0019] Further, the preparation steps of the carboxyl-modified graphene include: adding graphene (sheet structure, sheet diameter of 1-10 μm) to a nitric acid solution with a concentration of 0.5-1.0 mol / L, refluxing at 60-80℃ for 3-5 h, filtering, washing until neutral, and drying to obtain carboxyl-modified graphene.

[0020] In the above scheme, the groove structure includes a spiral groove, preferably a honeycomb-spiral composite microgroove structure.

[0021] Preferably, the honeycomb-spiral composite groove structure includes a spiral main groove with an inclination angle of 10-20° and polygonal honeycomb secondary grooves distributed in a periodic array behind the main groove.

[0022] The spiral main groove is distributed in a continuous and equidistant spiral line along the surface of the wear-resistant ring, with a pitch of 1.8-2.4 mm, a depth of 0.20-0.30 mm, and a width of 0.25-0.35 mm.

[0023] The array of polygonal honeycomb sub-grooves is arranged periodically along the axial direction of the helical main groove at a pitch (i.e., 1.8-2.4 mm) the same as the helical pitch. Within each cycle, the honeycomb sub-grooves are located after the adjacent helical main groove, with a unit side length of 0.4-0.6 mm and a depth of 0.10-0.20 mm. The honeycomb units are interconnected, as are the honeycomb units with adjacent helical main grooves, through microchannels with a width of 0.08-0.12 mm, thus forming a continuous composite mesh structure on the surface that combines axial heat conduction paths (helical main grooves) with radial stress dispersion nodes (honeycomb sub-grooves).

[0024] Furthermore, the composite groove structure is processed by laser micro-engraving and nano-imprinting composite technology, which can effectively increase the specific surface area and thermal conductivity, and stabilize the dynamic friction coefficient in the range of 0.13-0.15.

[0025] Furthermore, the polyurethane-graphene composite material layer also contains carbon nanotubes, the amount of which accounts for 3-8% of the mass of the thermoplastic polyurethane elastomer.

[0026] In the above scheme, the inner layer, middle layer and outer layer are bonded together by an adhesive layer.

[0027] In the above scheme, the adhesive layer is an epoxy-modified polyurethane adhesive, and its thickness is controlled between 0.05-0.1 mm.

[0028] Furthermore, the epoxy-modified polyurethane adhesive has a temperature resistance range of -40 to 180°C and exhibits no delamination after 50 cycles of thermal cycling at 31-152°C. Commercially available or laboratory-made epoxy-modified polyurethane adhesives meeting the above requirements can be used.

[0029] The above-mentioned method for preparing a flexible heat-insulating and wear-resistant ring includes the following steps: 1) Ceramic fiber reinforced silicone rubber material is coated and vulcanized onto the surface of a flexible shaft to obtain a ceramic fiber reinforced silicone rubber layer (heat insulation inner layer). 2) The aramid fiber braided layer is bonded to the heat insulation inner layer set in step 1) using epoxy modified polyurethane adhesive, and then subjected to first heat curing to obtain the aramid fiber braided layer (intermediate layer). 3) The polyurethane-graphene composite material layer is coated on the outer surface of the intermediate layer set in step 2) with epoxy modified polyurethane adhesive and then subjected to a second heating and curing process; and a microgroove structure is prepared on its surface by laser micromachining process.

[0030] In the above scheme, the first heating curing temperature is 75-85℃ and the time is 1.5-2.5 hours; the second heating curing temperature is 80-90℃ and the time is 2-3 hours.

[0031] This invention also provides an application of the above-mentioned flexible heat-insulating and wear-resistant ring, which is placed between the flexible shaft and the steel strip of a concrete vibrator. It maintains stable performance within the operating range of -40~160℃, effectively extending service life and reducing power loss. It is suitable for special environments such as nuclear power engineering, polar research stations, and metallurgical plants.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The flexible heat-insulating and wear-resistant ring of the present invention adopts a three-layer functional gradient composite structure. Through material system and process innovation, it achieves synergistic enhancement of heat insulation, wear resistance and mechanical properties. Specifically, it includes: the inner ceramic fiber reinforced silicone rubber layer system incorporates nano-ceramic heat stabilizers and forms a continuous heat insulation network through in-situ cross-linking process, which significantly improves the thermal stability and structural integrity of the material at high temperatures; the middle aramid fiber braided layer adopts a specific braiding angle (55°-65°) and pretreatment process, which can promote the enhancement of interlayer bonding and fatigue resistance; the outer polyurethane-graphene composite material introduces carboxyl-modified graphene and, in conjunction with the surface microgroove structure design, can significantly improve thermal conductivity and self-lubricating properties. 2) The present invention designs a honeycomb-spiral composite groove structure on the surface of the polyurethane-graphene composite material layer, combining a dual composite configuration of a spiral main groove and a polygonal honeycomb secondary groove. The spiral groove is used to guide heat diffusion along the axial direction, while the honeycomb groove can significantly improve heat dissipation efficiency and disperse contact stress by increasing the surface area and forming a micro-cavity structure. Furthermore, 50-80nm graphene microspheres are embedded in the groove to give the surface self-lubricating properties and further reduce the dynamic friction coefficient.

[0033] 3) The composite groove structure of this invention effectively increases the heat dissipation specific surface area and can form a two-phase heat dissipation channel where micro-airflow and lubricating film coexist under high-speed vibration conditions, thereby effectively controlling the temperature gradient of the shaft core; under extreme conditions such as 20Hz high-frequency vibration, 20MPa contact pressure and 160℃ high temperature, the micro-groove structure on the outer surface can still maintain excellent structural stability (deformation rate <0.8%), and is suitable for harsh construction scenarios with high temperature and high wear. Attached Figure Description

[0034] Figure 1 This is a schematic cross-sectional view of a flexible heat-insulating and wear-resistant ring mounting structure (flexible tube) according to one embodiment; Figure 2 This is a schematic diagram of the structure of the flexible heat-insulating and wear-resistant ring outer layer (polyurethane-graphene layer) described in Example 1. The linear structure in the figure represents the main groove of the spiral (single spiral structure), and the polygonal grid represents the secondary groove connected to it, which together constitute the basic composite groove structure. Figure 3This is a schematic diagram of the structure of the flexible heat-insulating and wear-resistant ring outer layer (polyurethane-graphene layer) described in Example 4. The diagram shows a double-helix groove structure that is distributed parallel to the axial direction. Figure 4 This is a schematic diagram of the structure of the flexible heat-insulating and wear-resistant ring outer layer (polyurethane-graphene layer) described in Example 6. The figure shows the optimized honeycomb-spiral composite groove structure, which forms a more efficient interconnection network with the main spiral groove through microchannels. In the diagram, 1 is the flexible shaft; 2 is the ceramic fiber reinforced silicone rubber layer; 3 is the aramid fiber braided layer; 4 is the polyurethane-graphene layer; 5 is the steel strip; and 6 is the rubber tube. Detailed Implementation

[0035] The technical solutions adopted in this invention are described in detail below through specific implementation examples. These descriptions are merely a part of the invention and do not represent all embodiments. Unless otherwise specified, the experimental methods used in this invention are conventional methods, and the instruments and equipment used are commercial products in this technical field.

[0036] Example 1

[0037] A flexible, heat-insulating, and wear-resistant ring for concrete vibrators, with the following installation structure: Figure 1 As shown; the installed structure includes a flexible shaft 1, a steel belt 5, and a flexible heat-insulating and wear-resistant ring (ring tube) placed between the two. The flexible heat-insulating and wear-resistant ring tube adopts a three-layer composite structure: the inner layer is a ceramic fiber reinforced silicone rubber layer 2 with a thickness of 0.84mm ± 0.02mm; the middle layer is an aramid fiber braided layer 3 with a thickness of 0.36mm ± 0.02mm; and the outer layer is a polyurethane-graphene composite material layer 4 with a thickness of 0.24mm ± 0.02mm; the thickness ratio of the three layers (inner, middle, and outer layers) is 7:3:2. The preparation method of the flexible heat-insulating and wear-resistant ring includes the following steps: 1) A ceramic fiber reinforced silicone rubber layer 2 is formed in situ on the surface of the flexible shaft 1: First, prepare the rubber compound, following these steps: a. Ingredients and pretreatment: By weight, take 100 parts of methyl vinyl silicone rubber raw rubber (grade 110-2), 30 parts of alumina ceramic fibers (fiber diameter 8-12μm, length 100-150μm) that have been heat-treated at 800℃ for 2 hours and surface-modified with silane coupling agent (KH-550), 12 parts of nano alumina particles (particle size 10-30nm), 6 parts of fumed silica (grade A-200) and 0.8 parts of silane coupling agent (KH-550).

[0038] b. Base material mixing: Plasticize the weighed methyl vinyl silicone rubber raw rubber on a two-roll mill for 3-5 minutes, then add fumed silica, pretreated ceramic fiber and nano alumina particles in sequence, and pass through the mill 10-15 times under the conditions of roller temperature 40-60℃ and roller gap 0.5-1.0mm to make the components evenly mixed and dispersed.

[0039] c. Add crosslinking agent: Add 2.2 parts of dicumyl peroxide (DCP) crosslinking agent to the above uniformly mixed base material, and continue to mix for 5-8 minutes at the same roller temperature until the crosslinking agent is uniformly dispersed to obtain a compound that can be molded.

[0040] Subsequently, the obtained compound is evenly wrapped or filled around the outer periphery of the flexible shaft 1, which has been pre-coated with a release agent, and immediately placed into a special molding die. It is then molded and vulcanized at 170℃ and 12MPa for 18 minutes. After demolding, it is further vulcanized in a 170℃ oven for 3 hours. Through this in-situ molding and vulcanization process, the compound directly cross-links and cures on the surface of the flexible shaft, forming a uniformly thick and firmly bonded ceramic fiber reinforced silicone rubber layer 2 (0.84mm ± 0.02mm thick), which serves as the inner heat insulation layer.

[0041] 2) The aramid fiber braided layer 3 is bonded to the heat insulation inner layer with a 16-ply × 16-ply twill braided structure using epoxy modified polyurethane adhesive (temperature resistant type, brand EPU-102). The thickness of the adhesive layer is controlled at 0.05-0.1mm, and cured at 80℃ for 2 hours. 3) The polyurethane-graphene composite material layer 4 is coated onto the outer surface of the middle layer using the above-mentioned epoxy-modified polyurethane adhesive (adhesive layer thickness is 0.05-0.1mm), and cured at 80°C for 2 hours; the polyurethane-graphene composite material layer is prepared by the following method: Step U1: Composite film preparation: 100 parts by weight of thermoplastic polyurethane elastomer (TPU, grade 1185A) was dissolved in 450 parts of N,N-dimethylformamide, 6 parts of carboxylated modified graphene and 1.5 parts of dispersant BYK-163 were added, and the mixture was dispersed by high-speed shearing and then cast into a film. The film was dried at 95°C to remove the solvent, resulting in a composite film with a thickness of 0.24 mm ± 0.02 mm.

[0042] Step U2: Groove structure machining (corresponding) Figure 2 (Structure shown) A single spiral groove structure with an inclination angle of 15°, a pitch of 2.0 mm, a depth of 0.22 mm ± 0.01 mm, and a line width of 0.30 mm was fabricated on the surface of a composite film using laser micromachining. This structure does not have a honeycomb sub-groove and aims to achieve basic heat dissipation and friction optimization through spiral guidance.

[0043] Step U3: Functionalization of surface graphene microspheres: The prepared grooved film is immersed in a dispersion containing 50-80nm graphene microspheres (graphene microsphere concentration is 1.25mg / mL) for 10-15 minutes, then removed and dried at 90℃ for 30 minutes, so that the graphene microspheres are embedded in the surface and interior of the groove to form a self-lubricating functional layer.

[0044] Step U4: Bonding and Curing: The functionalized composite film was coated onto the outer surface of the middle layer using an epoxy-modified polyurethane adhesive and cured at 80°C for 2 hours to complete the integration of the polyurethane-graphene composite material layer.

[0045] The obtained device was tested under ambient temperature of 25℃ and vibration frequency of 10.5Hz±0.5Hz. The results showed that, under the same conditions, compared with the surface temperature of the flexible shaft of a traditional vibrator (approximately 150℃±5℃), the surface temperature of the flexible shaft using the device of this embodiment was reduced to 78℃±2℃; the dynamic friction coefficient was stabilized at 0.14±0.01, the torque carrying capacity reached 512 N·m, and the fatigue life was 1.23×10⁻⁶. 6 Furthermore, its vibration energy transmission efficiency reaches 88.5% ± 1.5%. The above data indicate that the structure in this embodiment has significant improvements over traditional structures in terms of heat insulation, wear resistance, load-bearing capacity, and fatigue life, while maintaining highly efficient vibration transmission performance.

[0046] Example 2

[0047] A flexible heat-insulating and wear-resistant ring and heat-insulating and wear-resistant device are prepared in a manner largely the same as in Example 1, except that a three-layer thickness ratio of 7:4:2 (inner layer, middle layer, outer layer) is adopted. Specifically, the inner ceramic fiber reinforced silicone rubber layer 2 has a thickness of 0.84mm ± 0.02mm, the middle aramid fiber braided layer 3 is thickened to 0.48mm ± 0.02mm, and the outer layer remains at 0.24mm ± 0.02mm. The thickened middle layer adopts an 18-strand × 18-strand dense twill braided structure.

[0048] Tested: The torque bearing capacity of the resulting heat-insulating and wear-resistant device was increased to 580 N·m, a 13.3% improvement compared to Example 1; under the vibration condition of C40 high-strength concrete, its fatigue resistance was significantly improved, after 2.1 × 10⁻⁶ mm. 6 No delamination was observed after the second vibration test; furthermore, due to the thickening of the middle layer, the overall density increased to 2.18 g / cm³. 3 However, by optimizing the depth of the outer groove to 0.20mm, the coefficient of friction is still maintained at 0.15±0.01; the resulting heat-insulating and wear-resistant device is particularly suitable for continuous pouring of large-volume concrete, and the temperature fluctuation does not exceed ±3℃ during 8 hours of continuous operation.

[0049] Example 3

[0050] A flexible heat-insulating and wear-resistant ring and heat-insulating and wear-resistant device are prepared in a manner largely the same as in Example 1, except that a three-layer thickness ratio of 7:3.5:2 is adopted, specifically: the inner ceramic fiber reinforced silicone rubber layer is 0.84mm ± 0.02mm, the middle aramid fiber braided layer is 0.42mm ± 0.02mm, and the outer polyurethane-graphene composite material layer is 0.24mm ± 0.02mm; and the middle layer adopts a gradient density braiding technology, specifically: with the thickness center line as the boundary, the approximately 0.18mm thickness portion near the inner layer adopts a 12-strand × 12-strand braided structure, and the approximately 0.24mm thickness portion near the outer layer is densified to a 16-strand × 16-strand braided structure.

[0051] Testing revealed that the obtained heat-insulating and wear-resistant device maintained a torque capacity of 540 N·m while controlling the axial temperature difference at 14.2℃ ± 0.3℃; the vibration energy transmission efficiency reached 92.5%, an improvement of 4.8% compared to Example 1. It is particularly suitable for high-frequency vibration (15-20Hz) of precast components, and the wear is only 0.076mm after 1 million vibrations.

[0052] Example 4

[0053] A flexible heat-insulating and wear-resistant ring adopts a 7:4:4 three-layer composite structure design; specifically, it includes: an inner layer of ceramic fiber reinforced silicone rubber layer of 0.84mm±0.02mm, a middle layer of aramid fiber braided layer of 0.48mm±0.02mm, and an outer layer of polyurethane-graphene composite material layer thickened to 0.48mm±0.02mm.

[0054] The preparation method of the flexible heat-insulating and wear-resistant ring includes the following steps: 1) In-situ molding of a ceramic fiber reinforced silicone rubber layer on the surface of a flexible shaft, the specific preparation and molding process includes: a. Preparation of the compound: By weight, take 100 parts of methyl vinyl silicone rubber raw rubber (grade 110-2), 30 parts of alumina ceramic fibers (fiber diameter 8-12μm, length 100-150μm) that have been heat-treated at 800℃ for 2 hours and surface-modified with silane coupling agent (KH-550), 12 parts of nano-alumina particles (particle size 10-30nm), 6 parts of fumed silica (grade A-200), and 0.8 parts of silane coupling agent (KH-550). Plasticize the raw rubber on a two-roll mill, then add the fumed silica, modified ceramic fibers, and nano-alumina particles sequentially. Mix thoroughly in a thin pass at a roll temperature of 40-60℃ and a roll gap of 0.5-1.0mm until homogeneous. Then add 2.2 parts of dicumyl peroxide (DCP) crosslinking agent and continue mixing until homogeneous to obtain the compound.

[0055] b. In-situ compression molding: The above-mentioned rubber compound is evenly wrapped or filled onto the surface of the flexible shaft, and then placed into a special molding mold. Compression molding is performed at 170℃ and 12MPa for 18 minutes. After demolding, a second curing is carried out in a 170℃ oven for 3 hours. Through this process, the rubber compound directly cross-links and cures on the shaft surface, forming a firmly bonded ceramic fiber reinforced silicone rubber layer with a thickness of 0.84mm ± 0.02mm, thus establishing a stable thermal insulation base.

[0056] 2) Subsequently, a high-strength aramid fiber braided layer (16-ply × 16-ply twill structure) is used to cover the inner layer, and 0.05-0.1mm thick epoxy modified polyurethane adhesive (brand name EPU-102) is used for bonding to ensure interlayer bonding strength, and then cured at 80℃ for 2 hours. 3) Preparation of the outer polyurethane-graphene composite layer: The specific preparation steps are as follows: 100 parts by weight of thermoplastic polyurethane elastomer (TPU, grade 1185A) is dissolved in 450 parts of N,N-dimethylformamide, 7 parts of carboxylated modified graphene and 1.5 parts of dispersant BYK-163 are added, and after high-speed shear dispersion, the mixture is cast into a film and dried at 95°C to remove the solvent, resulting in a composite film with a thickness of 0.48mm±0.02mm; and a double helical groove structure with a depth of 0.25mm, a pitch of 1.8mm, a helix angle of 12° and a line width of 0.32mm is made on its surface by laser micromachining process to optimize the heat dissipation path and friction characteristics.

[0057] Testing revealed that the resulting flexible, heat-insulating, and wear-resistant ring structure performed exceptionally well under the harsh conditions of steel fiber reinforced concrete: wear was only 0.063 mm / 200 hours, thermal conductivity increased to 1.68 W / m·K, and the core temperature remained stable at 72℃±1℃. Furthermore, in ultra-high-rise pumped concrete construction, even under high pressure of 0.8 MPa, its frictional characteristics remained stable, and its torque transmission efficiency was significantly superior to traditional structures. This design is particularly suitable for high-strength, high-wear construction scenarios, combining excellent durability and thermal management performance.

[0058] Example 5

[0059] A flexible, heat-insulating, and wear-resistant ring employs a three-layer composite structure based on a 7:4:2 ratio. The device comprises: an inner layer of 0.84 mm ± 0.02 mm ceramic fiber reinforced silicone rubber (with nano-boron nitride heat stabilizer); a middle layer of 0.48 mm ± 0.02 mm low-temperature aramid fiber braided layer; and an outer layer of 0.24 mm ± 0.02 mm polyurethane-graphene composite material (further composited with carbon nanotubes). The method for preparing the heat-insulating and wear-resistant device includes the following steps: 1. Preparation and in-situ composite of ceramic fiber reinforced silicone rubber layers: a. Preparation of the compound: By weight, weigh 100 parts of methyl vinyl silicone rubber raw rubber, 28 parts of ceramic fiber modified with silane coupling agent after heat treatment at 780℃ for 2.5 hours, 10 parts of nano boron nitride particles, 5 parts of fumed silica, and 0.6 parts of silane coupling agent. Plasticize the raw rubber on a two-roll mill at 45-55℃ for 4 minutes. Then, add the fumed silica, modified ceramic fiber, and nano boron nitride particles sequentially, and mix thoroughly 12 times until homogeneous. Finally, add 2.0 parts of dicumyl peroxide (DCP) crosslinking agent and continue mixing until uniformly dispersed to obtain the compound.

[0060] b. In-situ compression molding: The above-mentioned rubber compound is directly and evenly wrapped around the surface of the flexible shaft, and then placed into a molding die. Compression molding is performed at 168℃ and 10MPa for 20 minutes. After demolding, a second curing is carried out in a 170℃ oven for 4 hours. Through this in-situ curing process, the rubber compound cross-links and cures on the shaft surface, forming a strong, heat-insulating inner layer with a thickness of 0.84mm ± 0.02mm.

[0061] 2. Coating and bonding of aramid fiber braided layers: Para-aramid filaments with a linear density of 1670 dtex were selected, impregnated with a surface treatment agent at 75℃ for 8 minutes, and then dried at 120℃. A aramid fiber braided sleeve was made by using an 18-ply × 18-ply dense twill weave structure, with the weave angle controlled at 60°±2° and the weave density at 90%±3%. Using a low-temperature resistant epoxy-modified polyurethane adhesive (brand name EPU-102LT), with a coating thickness of 0.08mm ± 0.02mm, the woven layer is wrapped around the inner surface and cured at 75℃ for 2.5 hours.

[0062] 3. Molding and processing of polyurethane-graphene composite material layers: 100 parts by weight of thermoplastic polyurethane elastomer (TPU, grade 1185A) was dissolved in 420 parts of N,N-dimethylformamide, 5 parts of carboxylated modified graphene and 5 parts of carboxylated multi-walled carbon nanotubes were added, along with 1.2 parts of dispersant BYK-163, and dispersed at 7000 r / min for 35 minutes. The dispersion was cast into a film and dried at 90°C to remove the solvent, resulting in a composite film with a thickness of 0.24 mm ± 0.02 mm. Micro-spiral grooves with a depth of 0.20 mm ± 0.01 mm and a pitch of 1.8 mm were fabricated on the surface of a thin film using laser micromachining technology. Subsequently, the film was immersed in a dispersion of graphene microspheres with a concentration of 1.25 mg / mL (graphene microsphere particle size 50-80 nm) and dried at 90 °C for 30 minutes to form a self-lubricating surface. The composite layer is bonded to the outer surface of the middle layer using epoxy-modified polyurethane adhesive, with the curing conditions the same as in step 2.

[0063] The heat-insulating and wear-resistant device prepared by the above method has a torque bearing capacity of 565 N·m at -30℃, a dynamic friction coefficient that is stable at 0.16±0.02, and an interlayer bonding strength retention rate of 98.2% after thermal shock testing. It is suitable for low-temperature operating environments such as polar research stations and construction in high-altitude and cold regions.

[0064] Example 6

[0065] A flexible, heat-insulating, and wear-resistant ring with a thickness ratio of 7:3:4. The inner layer is a ceramic fiber-reinforced silicone rubber layer with a thickness of approximately 0.84 mm; the middle layer is an aramid fiber braided layer with a thickness of approximately 0.36 mm; its material composition and preparation method are the same as those described in steps 1) and 2) of Example 1. The outer layer is a polyurethane-graphene composite material layer, thickened to 0.48mm±0.02mm. The preparation methods of the inner and middle layers are the same as in Example 1. The outer polyurethane-graphene composite material layer is thickened to 0.48mm±0.02mm, and an innovative "honeycomb-spiral" composite groove structure is designed. The composite groove consists of two parts: (1) a main groove extending spirally at a 15° angle, with a groove depth of 0.25mm±0.01mm, a groove width of 0.3mm, and a pitch of 2.4mm; (2) hexagonal honeycomb secondary grooves distributed between the main grooves, with a unit side length of 0.5mm and a groove depth of 0.15mm±0.005mm. Each honeycomb unit is connected to the main spiral groove through 3 radial microchannels with a width of 0.1mm.

[0066] The outer polyurethane-graphene composite layer is specifically fabricated using a laser micro-engraving and nanoimprinting composite process. The specific steps include: first, using a diamond tool to precisely machine a spiral main groove with an angle of 15°, a pitch of 2.4mm, a groove depth of 0.25mm ± 0.01mm, and a groove width of 0.3mm (accuracy ± 0.005mm); then, using an ultraviolet laser (wavelength 355nm) to etch hexagonal honeycomb secondary grooves in the area between the spiral main grooves, with a unit side length of 0.5mm and a depth of 0.15mm. The honeycomb cells, with a diameter of ±0.005 mm, are arranged axially at a period of 2.4 mm, consistent with the pitch of the spiral main groove. Each honeycomb cell is connected to the adjacent spiral main groove through three radial microchannels with a width of 0.1 mm, forming a periodically alternating spiral-honeycomb composite grid. Finally, the film with the processed composite grooves is immersed in a graphene microsphere dispersion (graphene microspheres with a particle size of 50-80 nm and a concentration of 2.0 mg / mL) at room temperature for 15-20 minutes. After removal, it is dried (e.g., at 90℃ for 30 minutes) to fully embed the graphene microspheres into the grooves and microchannel surfaces, forming a stable self-lubricating functional layer.

[0067] The above design has three advantages: First, the composite groove increases the surface area by 37%, forming a gas-liquid two-phase heat dissipation channel with a measured thermal conductivity of 1.85 W / m·K, controlling the core temperature gradient at 9℃ / cm under 160℃ conditions; Second, the 50-80nm graphene microspheres embedded in the groove achieve self-lubrication, stabilizing the dynamic friction coefficient at 0.13±0.005, a 7.1% reduction compared to Example 1; Third, the honeycomb structure disperses contact stress to 12 support points, and tests in steel fiber reinforced concrete show that after 200 hours of continuous operation, the wear is only 0.071mm, a 27.6% reduction compared to the ordinary structure.

[0068] Tests showed that the friction coefficient fluctuated within ±0.008 under 20Hz high-frequency vibration; the honeycomb structure maintained 98.3% integrity when subjected to 20MPa contact pressure; and the groove deformation rate was <0.8% after 100 hours of continuous operation at 160℃. This structure is particularly suitable for vibrating ultra-thick concrete layers (such as nuclear power plant containment vessel pouring), concrete construction containing hard aggregates (granite content >40%), and flooring operations in metallurgical plants with ambient temperatures >150℃, perfectly solving the equipment reliability problem under high-temperature and high-wear conditions.

[0069] Comparative Example 1 A flexible heat-insulating and wear-resistant ring is provided, wherein the surface of the outer polyurethane-graphene composite material layer is not provided with any groove structure, and the composition, thickness ratio and preparation process of the remaining materials are exactly the same as those in Example 6.

[0070] Tests showed that the device obtained in Comparative Example 1 exhibited a dynamic friction coefficient fluctuation range of ±0.025 under 20Hz high-frequency vibration, with the average friction coefficient increasing to 0.21. After 100 hours of continuous operation at 160℃, the core temperature gradient reached 22℃ / cm, significantly higher than the 9℃ / cm in Example 6. Simultaneously, due to the lack of grooves to guide heat dissipation and stress dispersion, the wear increased to 0.125mm after 200 hours, and the honeycomb structure experienced localized crushing under 20MPa pressure, with the integrity rate remaining at only 84.7%.

[0071] Comparative Example 2 A flexible heat-insulating and wear-resistant ring and heat-insulating and wear-resistant device are prepared in a manner largely the same as in Example 1, except that nano-alumina particles are not added to the ceramic fiber reinforced silicone rubber layer, and the high-temperature molding and secondary vulcanization steps in the in-situ crosslinking process are omitted, replaced by conventional one-step vulcanization molding. Specifically, the mixed rubber is placed in a flat vulcanizing machine and subjected to a single molding vulcanization at 160°C and 8MPa for 25 minutes, followed by demolding and cooling at room temperature to complete the molding process. The remaining structure, thickness, and outer layer treatment are consistent with Example 1.

[0072] Test results show that, under 150℃ conditions, the surface temperature of the flexible shaft in Comparative Example 2 only dropped to 112℃±5℃, and the thermal resistance decreased to 0.52K / W; after 50 cycles of thermal cycling, obvious delamination occurred; after 200 hours of continuous operation under 10.5Hz vibration, the wear reached 0.152mm, the torque carrying capacity decreased to 418N·m, and the fatigue life was only 6.8×10⁻⁶. 5 The number of times was significantly lower than the 1.23 × 10⁻⁶ in Example 1. 6 Second-rate.

[0073] Comparative Example 3 A flexible heat-insulating and wear-resistant ring and a heat-insulating and wear-resistant device are prepared in a manner that is largely the same as that in Example 2, except that the aramid fiber braided layer adopts a conventional plain weave structure with a braiding angle of 90° and the fiber surface pretreatment step is omitted. The other materials, thickness and outer layer structure are the same as those in Example 2.

[0074] Test results show that, under the C40 concrete vibration condition, Comparative Example 3, after 1.5 × 10⁻⁶ vibrations, showed that... 6 After one vibration, interlayer delamination occurred; the torque bearing capacity was 510 N·m, lower than 580 N·m in Example 2; during 8 hours of continuous operation, the temperature fluctuation reached ±8℃, and the fatigue resistance and thermal stability deteriorated significantly.

[0075] Comparative Example 4 A flexible heat-insulating and wear-resistant ring and a heat-insulating and wear-resistant device are prepared in a manner that is largely the same as that in Example 4, except that: no graphene is added to the outer polyurethane composite material and the surface is designed to be smooth without grooves. The rest of the structure, thickness and preparation process are the same as those in Example 4.

[0076] Test results show that in Comparative Example 4, the wear rate increased to 0.105 mm / 200 hours in steel fiber reinforced concrete, the thermal conductivity was only 1.02 W / m·K, and the core temperature rose to 92℃±3℃. Under a high pressure environment of 0.8 MPa, the friction coefficient fluctuated drastically, and the torque transmission efficiency decreased by about 18%, which could not meet the requirements of high-strength construction.

[0077] Comparative Example 5 A flexible heat-insulating and wear-resistant ring and a heat-insulating and wear-resistant device are prepared in a manner similar to that of Example 3, except that the three-layer structure adopts an equal thickness design (0.50 mm per layer), and the adhesive layer uses ordinary epoxy resin (non-modified polyurethane type) with an adhesive layer thickness of (0.05–0.15 mm). The other materials and processes are the same as in Example 3.

[0078] Test results show that, under high-frequency vibration of 15-20Hz, the axial temperature difference of Comparative Example 5 increased to 28.5℃±1.5℃, and the vibration energy transfer efficiency was only 83.2%; after 1 million vibrations, the wear was 0.132mm, and obvious cracking appeared between the layers after thermal cycling.

[0079] This invention solves the problems of thermal management, wear resistance and structural stability of flexible tubes for vibrating rods under high temperature and high wear conditions through a series of innovative methods such as multi-layer gradient structure design, interface synergistic control, precision microstructure processing and composite process optimization.

[0080] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are subject to the requirements of the present invention.

Claims

1. A flexible, heat-insulating, and wear-resistant ring, characterized in that, It comprises a three-layer functionally graded composite structure, wherein the inner layer is a ceramic fiber reinforced silicone rubber layer, the middle layer is an aramid fiber braided layer, and the outer layer is a polyurethane-graphene composite material layer; the ceramic fiber reinforced silicone rubber layer is obtained by cross-linking and compounding silicone rubber raw rubber, ceramic fiber and ceramic heat stabilizer as the main raw materials; the surface of the polyurethane-graphene composite material layer is provided with a microgroove structure.

2. The flexible heat-insulating and wear-resistant ring according to claim 1, characterized in that, The thickness of the ceramic fiber reinforced silicone rubber layer is 0.80-0.90 mm, and the thermal resistance is 0.85-0.90 K / W.

3. The flexible heat-insulating and wear-resistant ring according to claim 1, characterized in that, The ceramic heat stabilizer is one or more of nano-alumina and boron nitride particles; its dosage accounts for 10-15% of the total mass of the ceramic fiber reinforced silicone rubber layer; the ceramic fiber is at least one of alumina fiber, aluminum silicate fiber, and mullite fiber; the fiber diameter is 5-15 μm and the length is 50-200 μm. Its dosage accounts for 20-30% of the total mass of the ceramic fiber reinforced silicone rubber layer.

4. The flexible heat-insulating and wear-resistant ring according to claim 1, characterized in that, The specific preparation steps of the ceramic fiber reinforced silicone rubber layer include the following steps: S1. Ingredients: By weight, weigh 100 parts of methyl vinyl silicone rubber raw rubber, 25-35 parts of ceramic fiber, 10-15 parts of ceramic heat stabilizer, 5-8 parts of fumed silica, 2.0-2.5 parts of crosslinking agent and 0.5-1.0 parts of silane coupling agent. S2. Pretreatment: The weighed ceramic fibers are heat-treated at 750-800℃ for 2-3 hours, and then surface-modified with an alcohol solution of silane coupling agent. S3. Mixing: Plasticize the raw methyl vinyl silicone rubber, then add fumed silica, pretreated ceramic fiber, and ceramic heat stabilizer in sequence, and pass through the mixture 10-15 times at a roller temperature of 40-60℃ and a roller gap of 0.5-1.0mm. S4. Crosslinking: Add crosslinking agent and continue mixing and dispersing until uniform to obtain compound; S5. Molding and vulcanization: The obtained compound is molded at a temperature of 165-175℃ and a pressure of 10-15MPa. After demolding, it is heated for secondary vulcanization to obtain the ceramic fiber reinforced silicone rubber layer.

5. The flexible heat-insulating and wear-resistant ring according to claim 1, characterized in that, The thickness of the aramid fiber braided layer is 0.34-0.50 mm; the braiding angle is 55-65°; and the braiding density is 85-95%.

6. The flexible heat-insulating and wear-resistant ring according to claim 1, characterized in that, The polyurethane-graphene composite material layer is first compounded using thermoplastic polyurethane elastomer and carboxyl-modified graphene as the main raw materials, and then processed with a microgroove structure on the surface. Graphene microspheres are then embedded in the microgrooves.

7. The flexible heat-insulating and wear-resistant ring according to claim 1, characterized in that, The groove structure includes a spiral groove with an inclination angle of 10°-20° and a pitch of 1.8-2.4mm; the groove depth is 0.20-0.30mm and the width is 0.25-0.35mm.

8. The flexible heat-insulating and wear-resistant ring according to claim 1, characterized in that, The microgroove structure is a honeycomb-spiral composite groove structure, comprising a spiral main groove extending along the axial direction at a spiral angle of 10-20°, and a polygonal honeycomb secondary groove array alternately distributed at the rear end of the spiral line with a period of 1.8-2.4 mm along the axial direction of the spiral main groove; the unit side length of the polygonal honeycomb secondary groove is 0.4-0.6 mm, the depth is 0.10-0.20 mm, and the honeycomb units are connected to each other and the honeycomb and the spiral main groove are connected by microchannels with a width of 0.08-0.12 mm.

9. The method for preparing the flexible heat-insulating and wear-resistant ring according to any one of claims 1 to 8, characterized in that, Includes the following steps: 1) Ceramic fiber reinforced silicone rubber material is coated and vulcanized onto the surface of a flexible shaft to form a ceramic fiber reinforced silicone rubber layer; 2) The aramid fiber braided layer is bonded to the ceramic fiber reinforced silicone rubber layer formed in step 1) using an epoxy modified polyurethane adhesive, and then subjected to a first heat curing to obtain the intermediate layer; 3) The polyurethane-graphene composite material layer is coated with epoxy-modified polyurethane adhesive on the outer surface of the intermediate layer set in step 2), and then subjected to a second heating and curing process; and a microgroove structure is prepared on its surface by laser micromachining process.

10. The application of the flexible heat-insulating and wear-resistant ring according to any one of claims 1 to 8, characterized in that, The operating temperature is -40~160℃.

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