Carbon fiber roller and method of making the same

Abstract

The application discloses a carbon fiber roller shaft and a preparation method thereof, and belongs to the technical field of carbon fiber roller shafts. The preparation method comprises the following steps: processing an annular reverse buckling groove in an inner connecting section of a metal shaft head; adopting carbon fiber impregnated epoxy resin to perform winding forming on a core mold, performing pre-compaction treatment under vacuum bag pressure after winding is completed, making carbon fiber layers adhere to each other, and forming a carbon fiber composite material pipe blank which is not completely solidified; inserting the inner connecting section of the metal shaft head into an end inner cavity of the carbon fiber composite material pipe blank, embedding an end layer into the annular reverse buckling groove, filling modified epoxy resin glue at an interface, and solidifying to make the carbon fiber composite material pipe body and the metal shaft head form an end reverse buckling embedded integrated structure; and performing finishing processing on an outer circle of the carbon fiber composite material pipe body. The problems of insufficient connecting strength between the metal shaft head and the carbon fiber composite material pipe body, easy debonding of the interface, end stress concentration, and poor running precision stability of the roller shaft are solved.

Description

Technical Field

[0001] This application relates to a carbon fiber roller and its preparation method, belonging to the field of carbon fiber roller technology. Background Technology

[0002] Carbon fiber composites possess advantages such as low density, high specific strength, high specific modulus, and good fatigue resistance, making them suitable for use in rollers in printing, papermaking, film production, lithium battery electrode manufacturing, and textile industries. A carbon fiber roller typically consists of a carbon fiber composite tube and metal shaft ends at both ends of the tube. These metal shaft ends are used to connect to bearings, couplings, or transmission mechanisms, and the reliability of the connection between the metal shaft ends and the carbon fiber composite tube directly affects the roller's load-bearing capacity, rotational accuracy, and service life.

[0003] In existing carbon fiber rollers, the metal shaft head and the carbon fiber composite tube body are mostly connected by adhesive bonding, interference fit, screw fixing, or simple plug-in connection. Simple adhesive bonding mainly relies on the adhesive layer to transfer the load. Under high-speed rotation, repeated start-stop, or torque transmission conditions, interface debonding, adhesive layer cracking, or shaft head loosening are prone to occur. Interference fit or mechanical fastening methods are prone to stress concentration at the tube end, and may even damage the continuous carbon fiber layup structure, affecting the fatigue life and operational stability of the roller. Summary of the Invention

[0004] The purpose of this invention is to provide a carbon fiber roller and its preparation method, so as to improve the problems of insufficient connection strength between the metal shaft head and the carbon fiber composite tube, easy debonding at the interface, stress concentration at the end, and poor stability of roller running accuracy.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: According to one aspect of this application, a method for preparing a carbon fiber roller is provided, comprising the following steps: Step 1: Machine an annular undercut groove into the inner connecting section of the metal shaft head, and sandblast the inner surface of the annular undercut groove to make the surface roughness Ra 1.5-3.5μm; Step 2: Carbon fiber impregnated with epoxy resin is wound onto a mandrel at a winding temperature of 20-45℃ and a tension of 15-60N. After winding, pre-compacting is performed under vacuum bag pressure conditions. The pre-compacting vacuum degree is ≤-0.080MPa, the temperature is 40-70℃, and the time is 20-60min. This allows the carbon fiber layers to bond together, forming an incompletely cured carbon fiber composite tube blank. Step 3: Insert the inner connecting section of the metal shaft head into the end cavity of the carbon fiber composite tube blank, so that the end layup is embedded in the annular undercut groove, and fill the interface with modified epoxy resin. Perform segmented curing treatment under vacuum degree ≤-0.085MPa to form an end undercut embedded structure between the carbon fiber composite tube body and the metal shaft head. Step 4: Perform precision machining on the outer circle of the carbon fiber composite tube to ensure that the radial runout of the carbon fiber roller is ≤0.05mm and the surface roughness Ra is ≤0.8μm.

[0006] Optionally, in step two, the carbon fiber includes an axial layer, a transition layer, and a circumferential layer along the thickness direction of the tube. The axial layer has a layup angle of 0°, the circumferential layer has a layup angle of 80-90°, and the transition layer has a layup angle of ±45°.

[0007] Optionally, in step three, segmented curing includes pre-curing, main curing, and post-curing; The pre-curing temperature is 60-90℃ and the time is 1-3 hours; the main curing temperature is 120-160℃ and the time is 2-5 hours; and the post-curing temperature is 160-180℃ and the time is 1-4 hours.

[0008] Optionally, the preparation method of the modified epoxy resin adhesive includes: S1. Stir the epoxy resin at 25-60℃ for 10-60 min, add the polyethersulfone resin, and stir at 50-90℃ for 80-120 min to obtain a premix. S2. The nano-inorganic filler is placed in oxygen plasma for surface activation treatment. The treatment power is 100-300W, the pressure is 10-80Pa, and the time is 5-30min. Then, it is added to a mixed solution of ethanol and water and stirred and dispersed at 800-2000r / min. Then, a silane coupling agent is added and reacted at 60-80℃ for 2-4h. After centrifugation, washing, and drying, the modified nano-filler is obtained. S3. Add the modified nanofiller to the premixed liquid and ultrasonically disperse it at 200-800W for 5-30 minutes. Then add the short-cut carbon fibers and stir at 200-800r / min for 5-30 minutes. Then add the curing agent and accelerator and continue stirring at 200-800r / min for 5-30 minutes to obtain the modified epoxy resin adhesive.

[0009] Optionally, the epoxy resin is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin; And / or, the silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane and 3-methacryloyloxypropyltrimethoxysilane in a weight ratio of (2-5):1; And / or, the nano-inorganic filler is selected from one or more of nano-silica, nano-alumina, carbon nanotubes or graphene; And / or, the curing agent is selected from one or more of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and dodecenylsuccinic anhydride; And / or, the promoter is selected from one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, and benzyldimethylamine.

[0010] Optionally, the amount of polyethersulfone added is 8-20 wt% of the epoxy resin; And / or, the amount of the nano-inorganic filler added is 2-6 wt% of the epoxy resin; And / or, the amount of the silane coupling agent added is 5-12 wt% of the nano-inorganic filler; And / or, the amount of the chopped carbon fibers added is 0.5-5 wt% of the epoxy resin; And / or, the amount of the curing agent added is 70-90 wt% of the epoxy resin; And / or, the amount of the accelerator added is 0.5-2 wt% of the epoxy resin.

[0011] According to another aspect of this application, a carbon fiber roller is provided, which is prepared by the carbon fiber roller preparation method described in any of the preceding claims.

[0012] Optionally, the carbon fiber roller includes a carbon fiber composite tube and metal shaft heads disposed at both ends of the carbon fiber composite tube, wherein the metal shaft heads are locked to the carbon fiber tube.

[0013] Optionally, the inner connecting section of the metal shaft head is provided with an annular undercut groove, and the end of the carbon fiber composite tube is embedded in the annular undercut groove, forming a locking mechanical fitting structure with the annular undercut groove.

[0014] Optionally, the annular undercut groove is a stepped structure with 2-5 grooves spaced apart along the axial direction, the axial distance between adjacent annular undercut grooves is 5-10mm, the groove depth of each annular undercut groove is 0.3-1.2mm, the sidewall of the annular undercut groove forms an inverted conical surface that tapers outward in the axial direction, and the angle between the inverted conical surface and the axis of the metal shaft head is 70-85°.

[0015] The beneficial effects of this application include, but are not limited to: 1. The carbon fiber roller of this application, by setting an annular undercut groove in the inner connecting section of the metal shaft head, and embedding the end layup into the annular undercut groove in the state where the carbon fiber composite tube blank is not fully cured, and forming an end undercut integrated structure after segmented curing, can not only improve the mechanical locking strength between the metal shaft head and the carbon fiber composite tube body, but also avoid the problems of interface debonding and shaft head loosening that are easy to occur under the simple adhesive bonding method, thereby improving the pull-out resistance and torque transmission resistance of the roller.

[0016] 2. The carbon fiber roller of this application is sandblasted on the inner surface of the annular undercut groove, and a modified epoxy resin is filled between the end layup of the carbon fiber composite tube and the metal shaft head. The modified epoxy resin can penetrate into the gap of the end layup and the micro-pits on the sandblasted surface. After curing, a continuous interface transition layer is formed between the metal shaft head, the annular undercut groove and the carbon fiber end layup, thereby filling the assembly gap, increasing the interface bonding area, dispersing the end stress concentration, and making the pull-out force and torque more evenly transmitted to the carbon fiber composite tube.

[0017] 3. The carbon fiber roller of this application comprises a modified epoxy resin filler between the metal shaft head and the end of the carbon fiber composite tube, and the introduction of polyethersulfone resin, bissilane-modified nanofiller, chopped carbon fibers, and a curing agent. During the segmented curing process, the curing agent and epoxy resin form a cross-linked curing network, enabling the adhesive layer to form a stable bond with the roughened surface of the metal shaft head and the end layup of the carbon fiber composite tube. The bissilane-modified nanofiller, through the synergistic effect of epoxy groups and methacryloyloxy groups, improves the reaction compatibility, interfacial wettability, and dispersion stability of the nanofiller and epoxy resin system, thereby enhancing the adhesive layer's ability to wet and fill the micro-pits on the surface of the metal shaft head and the gaps in the carbon fiber end layup. The polyethersulfone resin improves the toughness of the adhesive layer, and the chopped carbon fibers form a bridging reinforcement structure. Together, they inhibit the propagation of cracks in the adhesive layer and alleviate the interfacial stress concentration between the metal shaft head and the carbon fiber composite tube, thereby improving the shear resistance, peel resistance, and fatigue resistance of the end connection area.

[0018] 4. The method for preparing the carbon fiber roller shaft of this application can improve the interlayer bonding quality, end fitting stability and overall dimensional accuracy of the carbon fiber composite tube by controlling the winding temperature, tension, vacuum pre-compaction conditions, segmented curing conditions and subsequent outer circle precision machining of the carbon fiber. This results in a carbon fiber roller shaft with lower radial runout and higher surface machining accuracy, thereby meeting the requirements for lightweight, high precision and operational stability under high-speed rotation conditions. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of the carbon fiber roller involved in the embodiments of this application.

[0020] Figure 2 This is a schematic diagram of the structure of the metal shaft head involved in the embodiments of this application.

[0021] List of components and reference numerals: 1. Carbon fiber composite tube body; 2. Metal shaft head; 3. Annular undercut groove. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0024] The metal shaft ends mentioned below are made of aluminum alloy or stainless steel, preferably 7075 aluminum alloy; the average particle size of the nano-inorganic filler is 50 nm; and the average length of the short-cut carbon fiber is 2 mm.

[0025] like Figure 1 and Figure 2 As shown, the carbon fiber roller of this application includes a carbon fiber composite tube body 1 and metal shaft heads 2 disposed at both ends of the carbon fiber composite tube body 1. The inner connecting section of the metal shaft head 2 is provided with an annular undercut groove 3. The end of the carbon fiber composite tube body 1 is embedded in the annular undercut groove 3, forming a locking mechanical fitting structure with the annular undercut groove 3. Through this structure, the metal shaft head 2 and the carbon fiber composite tube body 1 not only rely on adhesive bonding to transfer load, but also transfer axial tensile load and torsional load through the mechanical fitting action between the annular undercut groove 3 and the end layup, thereby improving the reliability of the end connection.

[0026] In this application, the inner connecting section refers to the axial section where the metal shaft head 2 extends into the inner cavity of the end of the carbon fiber composite tube 1 and forms a connection with the carbon fiber composite tube 1. The annular undercut groove refers to an annular groove structure that is continuously arranged circumferentially along the metal shaft head 2 and has an undercut limiting function in the axial section. Preferably, the annular undercut groove 3 is a stepped structure arranged 2-5 times axially, the axial distance between adjacent annular undercut grooves 3 is 5-10 mm, the groove depth of each annular undercut groove 3 is 0.3-1.2 mm, and the sidewall of the annular undercut groove 3 forms an inverted conical surface that tapers outward in the axial direction, with the inverted conical surface having an angle of 70-85° with respect to the axis of the metal shaft head. More preferably, the annular undercut groove 3 is a stepped structure arranged 3 times axially, the axial distance between adjacent annular undercut grooves 3 is 8 mm, the groove depth of each annular undercut groove 3 is 0.7 mm, and the sidewall of the annular undercut groove 3 forms an inverted conical surface that tapers outward in the axial direction, with the inverted conical surface having an angle of 80° with respect to the axis of the metal shaft head.

[0027] In this application, the incompletely cured carbon fiber composite tube blank refers to a tube blank in which the carbon fiber impregnated epoxy resin is wound and pre-compacted, and the resin matrix still has a certain fluidity or plasticity, and the end lay-up can enter the annular undercut groove 3 under the action of assembly pressure and vacuum compaction, and form an integrated connection structure with the metal shaft head 2 during the subsequent curing process.

[0028] The following examples and comparative examples all adopt the preferred embodiments described above.

[0029] Example 1 A method for preparing a carbon fiber roller includes the following steps: Step 1: Machine an annular undercut groove into the inner connecting section of the 7075 aluminum alloy shaft head, and sandblast the inner surface of the annular undercut groove to make the surface roughness Ra 2.5μm. Step 2: Carbon fiber impregnated with epoxy resin is wound onto a mandrel for molding. The carbon fiber includes an axial layer, a transition layer, and a circumferential layer along the thickness direction of the tube. The axial layer layup angle is 0°, the circumferential layer layup angle is 85°, and the transition layer layup angle is ±45°. The winding temperature is 30°C, and the tension is 40N. After winding, pre-compacting treatment is carried out under vacuum bag pressure conditions. The pre-compacting vacuum degree is ≤-0.080MPa, the temperature is 55°C, and the time is 40min, so that the carbon fiber layers are bonded together to form an incompletely cured carbon fiber composite tube blank. Step 3: Insert the inner connecting section of the metal shaft head into the end cavity of the carbon fiber composite tube blank, so that the end layup is embedded in the annular undercut groove, and fill the interface with modified epoxy resin. Perform segmented curing treatment under vacuum degree ≤-0.085MPa. The segmented curing includes pre-curing, main curing and post-curing. The pre-curing temperature is 75℃ and the time is 2h. The main curing temperature is 140℃ and the time is 3h. The post-curing temperature is 170℃ and the time is 2h, so that the carbon fiber composite tube body and the metal shaft head form an integrated structure with undercut end fitting. Step 4: Perform precision machining on the outer circle of the carbon fiber composite tube to ensure that the radial runout of the carbon fiber roller is ≤0.05mm and the surface roughness Ra is ≤0.8μm; The preparation methods for modified epoxy resin adhesives include: S1. Stir bisphenol A type epoxy resin at 40℃ for 30 min, add 15 wt% polyethersulfone resin, and stir at 70℃ for 100 min to obtain a premixed solution. S2. 4 wt% nano-silica was placed in oxygen plasma for surface activation treatment at a power of 200 W, a pressure of 45 Pa, and a time of 20 min. Then, a mixed solution of ethanol and water (volume ratio of ethanol to water of 3:1) was added and stirred and dispersed at 1500 r / min. Then, 8 wt% of 3-glycidyl etheroxypropyltrimethoxysilane and 3-methacryloyloxypropyltrimethoxysilane (weight ratio of 3:1) were added and reacted at 70 °C for 3 h. After centrifugation, washing, and drying, the modified nanofiller was obtained. S3. Add the modified nanofiller to the premixed liquid and ultrasonically disperse it at 500W for 20min. Then add 3wt% short-cut carbon fiber and stir at 500r / min for 20min. Then add 80wt% methyltetrahydrophthalic anhydride and 1.2wt% 2-methylimidazole and continue stirring at 500r / min for 20min to obtain the modified epoxy resin adhesive.

[0030] Example 2 A method for preparing a carbon fiber roller includes the following steps: Step 1: Machine an annular undercut groove into the inner connecting section of the 7075 aluminum alloy shaft head, and sandblast the inner surface of the annular undercut groove to make the surface roughness Ra 1.5μm. Step 2: Carbon fiber impregnated with epoxy resin is wound onto a mandrel for molding. The carbon fiber includes an axial layer, a transition layer, and a circumferential layer along the thickness direction of the tube. The axial layer layup angle is 0°, the circumferential layer layup angle is 80°, and the transition layer layup angle is ±45°. The winding temperature is 20°C, and the tension is 60N. After winding, pre-compacting treatment is carried out under vacuum bag pressure conditions. The pre-compacting vacuum degree is ≤-0.080MPa, the temperature is 40°C, and the time is 60min, so that the carbon fiber layers are bonded together to form an incompletely cured carbon fiber composite tube blank. Step 3: Insert the inner connecting section of the metal shaft head into the end cavity of the carbon fiber composite tube blank, so that the end layup is embedded in the annular undercut groove, and fill the interface with modified epoxy resin. Perform segmented curing treatment under vacuum degree ≤-0.085MPa. The segmented curing includes pre-curing, main curing and post-curing. The pre-curing temperature is 60℃ and the time is 3h. The main curing temperature is 120℃ and the time is 5h. The post-curing temperature is 160℃ and the time is 4h, so that the carbon fiber composite tube body and the metal shaft head form an integrated structure with undercut end fitting. Step 4: Perform precision machining on the outer circle of the carbon fiber composite tube to ensure that the radial runout of the carbon fiber roller is ≤0.05mm and the surface roughness Ra is ≤0.8μm; The preparation methods for modified epoxy resin adhesives include: S1. Stir bisphenol F type epoxy resin at 25°C for 60 min, add 8 wt% polyethersulfone resin, and stir at 50°C for 120 min to obtain a premixed solution. S2. 2wt% nano-alumina was placed in oxygen plasma for surface activation treatment at a power of 100W, a pressure of 80Pa, and a time of 5min. Then, a mixed solution of ethanol and water (volume ratio of ethanol to water of 3:1) was added and stirred and dispersed at 800r / min. Then, 5wt% of 3-glycidyl etheroxypropyltrimethoxysilane and 3-methacryloyloxypropyltrimethoxysilane in a weight ratio of 2:1 were added and reacted at 60℃ for 4h. After centrifugation, washing, and drying, the modified nanofiller was obtained. S3. Add the modified nanofiller to the premixed solution and ultrasonically disperse it at 200W for 30min. Then add 0.5wt% short-cut carbon fiber and stir at 200r / min for 30min. Then add 70wt% methylhexahydrophthalic anhydride and 0.5wt% 2-ethyl-4-methylimidazole and continue stirring at 200r / min for 30min to obtain the modified epoxy resin adhesive.

[0031] Example 3 A method for preparing a carbon fiber roller includes the following steps: Step 1: Machine an annular undercut groove into the inner connecting section of the 7075 aluminum alloy shaft head, and sandblast the inner surface of the annular undercut groove to make the surface roughness Ra 3.5μm. Step 2: Carbon fiber impregnated with epoxy resin is wound onto a mandrel for molding. The carbon fiber includes an axial layer, a transition layer, and a circumferential layer along the thickness direction of the tube. The axial layer layup angle is 0°, the circumferential layer layup angle is 90°, and the transition layer layup angle is ±45°. The winding temperature is 45°C, and the tension is 15N. After winding, pre-compacting treatment is carried out under vacuum bag pressure conditions. The pre-compacting vacuum degree is ≤-0.080MPa, the temperature is 70°C, and the time is 20min, so that the carbon fiber layers are bonded together to form an incompletely cured carbon fiber composite tube blank. Step 3: Insert the inner connecting section of the metal shaft head into the end cavity of the carbon fiber composite tube blank, so that the end layup is embedded in the annular undercut groove, and fill the interface with modified epoxy resin. Perform segmented curing treatment under vacuum degree ≤-0.085MPa. The segmented curing includes pre-curing, main curing and post-curing. The pre-curing temperature is 90℃ and the time is 1h. The main curing temperature is 160℃ and the time is 2h. The post-curing temperature is 180℃ and the time is 1h, so that the carbon fiber composite tube body and the metal shaft head form an integrated structure with undercut end fitting. Step 4: Perform precision machining on the outer circle of the carbon fiber composite tube to ensure that the radial runout of the carbon fiber roller is ≤0.05mm and the surface roughness Ra is ≤0.8μm; The preparation methods for modified epoxy resin adhesives include: S1. Stir bisphenol A type epoxy resin at 60℃ for 10 min, add 20wt% polyethersulfone resin, and stir at 90℃ for 80 min to obtain a premixed solution. S2. 6 wt% nano-silica was placed in oxygen plasma for surface activation treatment at a power of 300 W, a pressure of 10 Pa, and a time of 30 min. Then, a mixed solution of ethanol and water (volume ratio of ethanol to water of 3:1) was added and stirred and dispersed at 2000 r / min. Then, 12 wt% of 3-glycidyl etheroxypropyltrimethoxysilane and 3-methacryloyloxypropyltrimethoxysilane in a weight ratio of 5:1 were added and reacted at 80 °C for 2 h. After centrifugation, washing, and drying, the modified nanofiller was obtained. S3. Add the modified nanofiller to the premixed liquid, ultrasonically disperse it at 800W for 5min, then add 5wt% short-cut carbon fiber, stir at 800r / min for 5min, then add 90wt% hexahydrophthalic anhydride and 2wt% benzyl dimethylamine, and continue stirring at 800r / min for 5min to obtain the modified epoxy resin adhesive.

[0032] Comparative Example 1 The difference from Example 1 is that in step one, the annular undercut groove is not machined on the inner connecting section of the 7075 aluminum alloy shaft head. Instead, the inner connecting section is machined into a smooth cylindrical surface and the smooth cylindrical surface is sandblasted to make the surface roughness Ra 2.5μm.

[0033] Comparative Example 2 The difference from Example 1 is that in step one, an annular straight groove is machined into the inner connecting section of the 7075 aluminum alloy shaft head (without machining an inverted conical surface), and the inner surface of the annular straight groove is sandblasted to make the surface roughness Ra 2.5μm.

[0034] Comparative Example 3 The difference from Example 1 is that in step two, after the carbon fiber is impregnated with epoxy resin and wound, it is not subjected to vacuum bag pre-compression treatment, but directly proceeds to step three for insertion and glue filling.

[0035] Comparative Example 4 The difference from Example 1 is that in step two, after the carbon fiber impregnated with epoxy resin is wound on the mandrel, it is not pre-compacted to obtain an incompletely cured carbon fiber composite tube blank. Instead, the wound carbon fiber is directly placed under vacuum bag pressure for complete curing. The specific curing conditions are: vacuum degree ≤ -0.085MPa, pre-curing temperature 75℃, time 2h, main curing temperature 140℃, time 3h, and post-curing temperature 170℃, time 2h. After curing, the tube is demolded to obtain a cured carbon fiber composite tube. In step three, the inner connecting section of the metal shaft head is inserted into the inner cavity of the cured carbon fiber composite tube, and modified epoxy resin is injected at the interface. After the injection is completed, the adhesive layer is cured under a vacuum of ≤-0.085MPa. The curing conditions are: pre-curing temperature 75℃, time 2h, main curing temperature 140℃, time 3h, and post-curing temperature 170℃, time 2h.

[0036] Comparative Example 5 The difference from Example 1 is that in step three, segmented curing was not used, but rather constant temperature curing at 140°C for 5 hours was performed.

[0037] Comparative Example 6 The difference from Example 1 is that the epoxy resin adhesive was not modified, and the preparation method of the epoxy resin adhesive includes: Bisphenol A type epoxy resin was stirred at 40℃ for 30 min, then 80 wt% methyltetrahydrophthalic anhydride and 1.2 wt% 2-methylimidazole were added, and stirring was continued at 500 r / min for 20 min to obtain epoxy resin adhesive.

[0038] Comparative Example 7 The difference from Example 1 is that the weight ratio of 3-glycidoxypropyltrimethoxysilane to 3-methacryloyloxypropyltrimethoxysilane is 10:1.

[0039] Comparative Example 8 The difference from Example 1 is that the polyethersulfone resin is replaced with polyphenylene sulfone resin.

[0040] Comparative Example 9 The difference from Example 1 is that chopped carbon fibers are replaced with glass fibers.

[0041] Performance testing The carbon fiber rollers prepared in Examples 1-3 and Comparative Examples 1-9 were tested for end connection performance and running accuracy. The test items included shaft head pull-out strength, maximum transmitted torque, radial runout after fatigue, and interface shear strength.

[0042] The test method for the pull-out strength of the shaft head is as follows: the carbon fiber composite tube is fixed, and a load is applied along the axial direction of the metal shaft head on a universal testing machine at a loading speed of 2 mm / min. The maximum load when the metal shaft head has obvious displacement relative to the tube body or when the connection fails is recorded.

[0043] The maximum transmitted torque test method is as follows: fix the carbon fiber composite tube, apply a gradually increasing torque to the metal shaft head, and record the maximum torque when interface slippage, adhesive layer damage, or end connection failure occurs.

[0044] The method for testing radial runout after fatigue is as follows: the carbon fiber roller is installed on the fatigue test bench and run continuously for 100 hours under the conditions of 3000 r / min and 300 N radial load. After the test, the radial runout in the middle of the roller is detected by dial indicator.

[0045] The interface shear strength test method is as follows: take a sample from the end connection area, load it in a shear fixture at a loading speed of 1 mm / min, record the maximum load when the interface shear fails, and calculate the interface shear strength.

[0046] The test results are shown in Table 1.

[0047] Table 1. Test results of carbon fiber roller end connection performance and operational accuracy

[0048] Long-term operational stability tests were conducted on the carbon fiber rollers prepared in Examples 1-3 and Comparative Examples 1-9.

[0049] The test method is as follows: The carbon fiber roller is mounted on a high-speed rotating test bench and tested under the conditions of 5000 r / min rotation speed, 200 N radial load, and 200 h continuous operation time. After the test, the end of the roller is checked for loosening, interface cracking, abnormal vibration, or increased radial runout.

[0050] The test results are shown in Table 2.

[0051] Table 2. Results of Long-Term Operational Stability Test for Carbon Fiber Rollers

[0052] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing a carbon fiber roller, characterized in that, Includes the following steps: Step 1: Machine an annular undercut groove into the inner connecting section of the metal shaft head, and sandblast the inner surface of the annular undercut groove to make the surface roughness Ra 1.5-3.5μm; Step 2: Carbon fiber impregnated with epoxy resin is wound onto a mandrel at a winding temperature of 20-45℃ and a tension of 15-60N. After winding, pre-compacting is performed under vacuum bag pressure conditions. The pre-compacting vacuum degree is ≤-0.080MPa, the temperature is 40-70℃, and the time is 20-60min. This allows the carbon fiber layers to bond together, forming an incompletely cured carbon fiber composite tube blank. Step 3: Insert the inner connecting section of the metal shaft head into the end cavity of the carbon fiber composite tube blank, so that the end layup is embedded in the annular undercut groove, and fill the interface with modified epoxy resin. Perform segmented curing treatment under vacuum degree ≤-0.085MPa to form an end undercut embedded structure between the carbon fiber composite tube body and the metal shaft head. Step 4: Perform precision machining on the outer circle of the carbon fiber composite tube to ensure that the radial runout of the carbon fiber roller is ≤0.05mm and the surface roughness Ra is ≤0.8μm.

2. The method for preparing carbon fiber rollers according to claim 1, characterized in that, In step two, the carbon fiber includes an axial layer, a transition layer and a circumferential layer along the thickness direction of the tube. The axial layer has a layup angle of 0°, the circumferential layer has a layup angle of 80-90°, and the transition layer has a layup angle of ±45°.

3. The method for preparing the carbon fiber roller according to claim 1, characterized in that, In step three, the segmented curing process includes pre-curing, main curing, and post-curing. The pre-curing temperature is 60-90℃ and the time is 1-3 hours; the main curing temperature is 120-160℃ and the time is 2-5 hours; and the post-curing temperature is 160-180℃ and the time is 1-4 hours.

4. The method for preparing the carbon fiber roller according to claim 1, characterized in that, The preparation method of the modified epoxy resin adhesive includes: S1. Stir the epoxy resin at 25-60℃ for 10-60 min, add the polyethersulfone resin, and stir at 50-90℃ for 80-120 min to obtain a premix. S2. The nano-inorganic filler is placed in oxygen plasma for surface activation treatment. The treatment power is 100-300W, the pressure is 10-80Pa, and the time is 5-30min. Then, it is added to a mixed solution of ethanol and water and stirred and dispersed at 800-2000r / min. Then, a silane coupling agent is added and reacted at 60-80℃ for 2-4h. After centrifugation, washing, and drying, the modified nano-filler is obtained. S3. Add the modified nanofiller to the premixed liquid and ultrasonically disperse it at 200-800W for 5-30 minutes. Then add the short-cut carbon fibers and stir at 200-800r / min for 5-30 minutes. Then add the curing agent and accelerator and continue stirring at 200-800r / min for 5-30 minutes to obtain the modified epoxy resin adhesive.

5. The method for preparing the carbon fiber roller according to claim 4, characterized in that, The epoxy resin is bisphenol A type epoxy resin or bisphenol F type epoxy resin; And / or, the silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane and 3-methacryloyloxypropyltrimethoxysilane in a weight ratio of (2-5):1; And / or, the nano-inorganic filler is selected from one or more of nano-silica, nano-alumina, carbon nanotubes or graphene; And / or, the curing agent is selected from one or more of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and dodecenylsuccinic anhydride; And / or, the promoter is selected from one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, and benzyldimethylamine.

6. The method for preparing the carbon fiber roller according to claim 4, characterized in that, The amount of polyethersulfone added is 8-20 wt% of the epoxy resin; And / or, the amount of the nano-inorganic filler added is 2-6 wt% of the epoxy resin; And / or, the amount of the silane coupling agent added is 5-12 wt% of the nano-inorganic filler; And / or, the amount of the chopped carbon fibers added is 0.5-5 wt% of the epoxy resin; And / or, the amount of the curing agent added is 70-90 wt% of the epoxy resin; And / or, the amount of the accelerator added is 0.5-2 wt% of the epoxy resin.

7. A carbon fiber roller, characterized in that, The carbon fiber roller is prepared by the carbon fiber roller preparation method according to any one of claims 1-6.

8. The carbon fiber roller according to claim 7, characterized in that, The carbon fiber roller includes a carbon fiber composite tube and metal shaft heads disposed at both ends of the carbon fiber composite tube, and the metal shaft heads are locked to the carbon fiber tube.

9. The carbon fiber roller according to claim 8, characterized in that, The inner connecting section of the metal shaft head is provided with an annular undercut groove, and the end of the carbon fiber composite tube is embedded in the annular undercut groove, forming a locking mechanical fitting structure with the annular undercut groove.

10. The carbon fiber roller according to claim 9, characterized in that, The annular undercut groove consists of 2-5 stepped structures spaced axially, with an axial spacing of 5-10 mm between adjacent annular undercut grooves. The groove depth of each annular undercut groove is 0.3-1.2 mm. The sidewall of the annular undercut groove forms an inverted conical surface that tapers outward axially, with the angle between the inverted conical surface and the axis of the metal shaft head being 70-85°.

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