A method for preparing a low-cost reinforcing preform for brake discs

Abstract

This invention provides a method for preparing a low-cost reinforced preform for brake discs, comprising the following steps: S1, preparing the mold core and winding it with carbon fiber mesh; S2, winding the carbon fiber bundle circumferentially; S3, winding the second layer of carbon fiber mesh; S4, alternating layering and winding to the target size; S5, Z-axis stitching and demolding and cutting. This invention innovatively adopts a composite structure of "carbon fiber winding + stitched fabric," with carbon fiber and mesh wound circumferentially and reinforced radially by interlacing stitched fibers. This simultaneously optimizes the structural strength and interlayer bonding performance of the carbon / carbon materials, significantly improving the overall strength of the mold by 60%-70% compared to existing technologies. The prepared preform is a ring-shaped integrated structure. This process is near-net-shape, saving 30%-40% of raw materials, achieving cost reduction and efficiency improvement. Furthermore, it can be cut into ring-shaped preforms according to the product thickness, allowing for the fabrication of multiple ring-shaped preforms in a single process, increasing production efficiency by 15-20% compared to traditional square felt manufacturing processes.

Description

Technical Field

[0001] This invention belongs to the field of composite material preform preparation technology, specifically relating to a method for preparing a low-cost reinforced preform for brake discs. Background Technology

[0002] Carbon / carbon or carbon / ceramic composites, with their high high-temperature structural strength, ablation resistance, and excellent friction and wear properties, have become the preferred material for high-end braking systems in aerospace, rail transportation, and automobiles. However, the mainstream technology for preform fabrication still employs the traditional vertical needle punching process. This process involves the needle breaking numerous continuous carbon fibers, leading to a reduction in preform strength. Because the carbon fiber bundles are arranged in strands, the high breakage rate after needle penetration results in the actual strength of the material being only 40-50% of the theoretical value. Furthermore, traditional needle-punched preforms exhibit a clear interface between the non-woven fabric layer and the mesh layer, which is alternately exposed during braking due to wear, causing fluctuations in the coefficient of friction and affecting braking stability, especially during high-speed, high-frequency braking.

[0003] A Chinese invention patent with publication number CN114645462A proposes a method for preparing a high-performance carbon fiber preform. It involves widening ordinary long carbon fibers to prepare a high-performance carbon fiber needle-punched preform. However, during the preparation of the preform, the alternating friction surfaces between the non-woven fabric and the mesh during the friction process have not been changed, and the problem of affecting braking stability still exists.

[0004] Based on this, a low-cost method for preparing brake disc reinforced preforms is proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a low-cost reinforcing preform for brake discs, in order to address the shortcomings of the prior art mentioned above.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a low-cost reinforcing preform for brake discs, comprising the following steps: S1. Preparation of the mold core and winding of the carbon fiber mesh; A TC4 titanium alloy annular mold core was selected. After the needle-punched carbon fiber mesh was wrapped around the surface of the mold core, it was temporarily fixed with polyimide high-temperature resistant wide paper tape. S2, carbon fiber bundles are wound in a circular direction; Untwisted carbon fiber bundles of the same specifications as S1 carbon fiber mesh are arranged side by side along the inner core axis of the mold and wound circumferentially using a high-precision winding equipment. After winding, polyimide high-temperature resistant wide paper tape is used for temporary fixation. S3, Second layer of carbon fiber mesh tire winding; On the surface of the S2 filament layer, a carbon fiber mesh of the same specification is wound according to the S1 parameters. After the winding is completed, it is temporarily fixed with polyimide high temperature resistant wide paper tape and rolled to ensure that the carbon fiber mesh adheres to the carbon fiber filament layer. S4. Alternately stack and wind to the target size; Repeat steps S2 to S3 to perform alternating layering and winding to obtain a semi-finished ring preform of the target size; S5, Z-direction stitching and demolding cutting; A high-precision CNC sewing machine is used, and carbon fiber thread is used for the sutures. Each suture unit is inserted radially and vertically into the outer edge of one end of the semi-finished preform, and then vertically out of the inner surface on the same side. Then, it is inserted and out in the opposite direction from the same point. After completing one row of sutures, the unit is moved clockwise by 10.0±0.02mm and sutured again until the semi-finished preform is sewn. After sewing, a CNC demolding device is used to demold the preform. After demolding, a high-precision cutting device is used to cut the preform to the target size, thus completing the preparation of the preform.

[0007] As a further explanation of the present invention, the dimensions of the mold core in S1 are: outer diameter 139.8±0.1mm, inner diameter 119.7±0.05mm, height 320.3±0.1mm, and the surface of the mold core is anodized with an oxide layer thickness of 6.2±0.1μm and a surface roughness Ra=0.8±0.05μm.

[0008] As a further explanation of the present invention, in S1, the width of the carbon fiber mesh is 300.2±0.05mm, and the areal density is 120.5±0.2g / m². 2 Monofilament interlacing density: 21±0.5 strands / cm 2 The single filament diameter is 7.0±0.03μm, the winding speed is 4.8±0.1r / min, and a constant tension of 70.3±0.2N is applied throughout the winding process, with tension fluctuation ≤±0.3N, to ensure that the carbon fiber mesh is laid flat and has a fit of ≥99.2% with the inner core of the mold. The circumferential interface overlap length of the carbon fiber mesh is 35.2±0.05mm, and the overlap is parallel to the axis of the inner core of the mold with a gap ≤0.12mm.

[0009] As a further explanation of the present invention, in S1, the dimensions of the polyimide high-temperature resistant wide paper tape are: 50.0±0.05mm×0.10±0.005mm, and the polyimide high-temperature resistant wide paper tape has a temperature resistance ≥120.5℃, a peel strength ≥1.8N / cm, a spacing of 80.0±0.5mm, and an edge alignment deviation ≤0.08mm.

[0010] As a further explanation of the present invention, in S2, the untwisted carbon fiber tow is specifically a T700 grade PAN-based untwisted carbon fiber tow, with a tow width of 20.0±0.05mm, a thickness of 0.150±0.005mm, a breaking strength ≥5.2GPa, an elastic modulus ≥235±2GPa, a twist ≤5 twists / m, and a uniformity ≥98.5%; Fifteen rolls of untwisted carbon fiber filaments, each weighing 5.0±0.05kg and measuring 3200±50m in length, are arranged side-by-side along the inner core axis of the mold, with a spacing of 0.20±0.02mm and a parallel deviation of ≤0.05mm from the inner core axis. The high-precision winding equipment winds the carbon fiber filaments circumferentially at a speed of 8.2±0.1 r / min, applying a constant tension of 70.3±0.2 N throughout the process, with tension fluctuation ≤±0.3 N. The angle between the untwisted carbon fiber filaments and the carbon fiber mesh layer is 90.0±0.2°, with a fit ≥99.3%. The mesh layer is covered to a coverage ≥99.8%, forming a filament layer with a thickness of 0.150±0.005 mm. The surface flatness Ra is ≤1.2±0.05 μm, and the overlap length of the untwisted carbon fiber filaments is 35.2±0.05 mm. At the filament overlap, apply epoxy-type carbon fiber special adhesive with a viscosity of 1500±50mPa·s in dots, with an application amount of 0.02±0.002g / dot and a spacing of 15±1mm. Cure at 25℃ for 10±1min. When fixing with tape, the overlap misalignment should be ≤0.03mm. Then roll with a pressure roller of 0.3±0.02MPa for 3.0±0.1s. The entire winding process is protected with argon gas of ≥99.999% purity and nitrogen gas flow rate of 15±0.5L / min. Tension sensor monitors the tension fluctuation to be ≤0.3N.

[0011] As a further explanation of the present invention, in S3, the winding speed is 4.8±0.1r / min, the tension is 70.3±0.2N, the fluctuation is ≤±0.3N, the overlap length of the carbon fiber mesh is 38.1±0.05mm, and it is offset from the overlap of the bottom carbon fiber mesh by 180.0±0.5°. The rolling process involves rolling twice with a pressure roller of 0.3±0.02MPa at a speed of 2.5±0.05mm / s, with an interval of 1.5±0.1s, to ensure that the carbon fiber mesh and the untwisted carbon fiber tow have a bonding degree of ≥99.3%.

[0012] As a further explanation of the present invention, in S4, a layer of carbon fiber mesh and a layer of untwisted carbon fiber bundle form a stack. After each stack is completed, it is rolled according to the parameters of S3, and additional vacuum pressing is added. The vacuum degree is -0.095±0.002MPa, the temperature is 60±1℃, the time is 8±0.5min, and the pressure is 0.5±0.02MPa to ensure that the interlayer gap is ≤0.01mm. In S4, the ambient temperature is 25.0±0.5℃ and the humidity is 45.0±1.0%RH. For every 50.0±0.1mm increase in outer diameter, the overlap length increases by 3.0±0.05mm, with a maximum of ≤45.0±0.05mm. After every 3 layers are completed, the layer is allowed to stand for 5.0±0.1min. After every 10 layers are completed, the interlayer thickness is measured using a 10MHz ultrasonic thickness gauge with an accuracy of ±0.005mm, with a measurement point spacing of 20±1mm and ≥20 points. When the deviation exceeds ±0.02mm, adjust the parameters until the preform has an outer diameter of 380.0±0.05mm, an inner diameter of 145.0±0.05mm, a thickness of 180.0±0.1mm, and an outermost surface of untwisted carbon fiber bundle layer. The resulting semi-finished preform has a surface flatness Ra≤1.0±0.05μm, an outer diameter runout ≤0.3±0.02mm, an inner diameter runout ≤0.2±0.01mm, and an overall roundness ≤0.4±0.02mm.

[0013] As a further explanation of the present invention, in S5, the suturing is performed in an environment of 25.0±0.5℃ and 45.0±1.0%RH. The suture needle is Φ1.00±0.01mm, the needle tip angle is 30.0±0.5°, the rounded corner radius is 0.10±0.01mm, the suture is T700 grade untwisted carbon fiber tow of the same specification as in S1, the tension is 70.3±0.2N throughout the process, the fluctuation is ≤±0.3N, the puncture frequency is 120±5 times / min, and the suture feed speed is 8±0.2mm / s.

[0014] As a further explanation of the present invention, in S5, a single stitching unit is inserted radially and vertically from one end of the semi-finished preform at a distance of 8.0±0.05mm from the radial outer edge, at a speed of 2.0±0.05mm / s, and then inserted and exited vertically from the same inner surface at a speed of 1.8±0.05mm / s. It then inserts and exits from the same point in the opposite direction, with a longitudinal length of 4.0±0.02mm and a stitch width of ≤0.30±0.01mm. The radial spacing between adjacent suture units is 4.0±0.02mm. After completing one row of suture units, the unit moves clockwise by 10.0±0.02mm, for a total of 38 rows of suture units. The circumferential center distance is 10.0±0.02mm, and the suture density is 10 rows / 100mm. 2 Every 5 rows are inspected with an instrument with an accuracy of ±0.005mm, and a CCD vision system is used simultaneously to monitor the suture quality in real time.

[0015] As a further explanation of the present invention, after the suturing in S5 is completed, it is left to stand in the same environment for 20.0±0.5 min, and then dust is removed by blowing with argon gas with a purity ≥99.999%, a pressure of 0.2±0.02MPa, and a speed of 10±1mm / s for 3±0.5 min; The CNC demolding equipment has a demolding speed of 5.0±0.1mm / min, a pressure of 0.8±0.05MPa, and real-time surface stress monitoring of ≤50±2MPa. After demolding, a high-precision cutting device with an accuracy of ±0.01mm is used to cut to a thickness of 30.0±0.02mm at a cutting speed of 3.0±0.05mm / s, using diamond tools with HRC≥65 and a rotation speed of 3000±50r / min. The cut flatness Ra is ≤1.0±0.05mm, and the perpendicularity deviation is ≤0. The material is cut to 0.03mm. After cutting, it is left to stand in the same environment for 15.0±0.5min to eliminate stress. Then, it is vacuum dried at 80±1℃ for 60±5min with a vacuum degree of -0.095±0.002MPa until the moisture content is ≤0.05±0.005%. Finally, it is polished with an 800±50 grit diamond polishing wheel at a speed of 1500±50r / min and a pressure of 0.3±0.02MPa for 5±0.5min until the surface roughness Ra≤0.8±0.05μm.

[0016] Compared with the prior art, the present invention has the following advantages: The structural strength and interlayer performance are greatly improved. This invention innovatively adopts a composite structure of "carbon fiber winding + sewn fabric". The circumferential structure is formed by the synergistic winding of carbon fiber and mesh, and the radial structure is reinforced by the interlacing of sewn fibers, thus constructing an integrated and stable structure. This optimizes the structural strength and interlayer bonding performance of carbon / carbon materials simultaneously, and the overall strength of the mold is significantly improved by 60%-70% compared with the existing technology.

[0017] Significantly improved raw material utilization: The preform prepared by this invention is a circular, integrated structure. This process is near-net-shape forming, which, compared to the traditional process of using square felt and requiring additional trimming of the inner circle and corner allowances, reduces raw material loss from the source, saving 30%-40% of raw materials and achieving cost reduction and efficiency improvement. Furthermore, it can be cut into circular preforms according to the product thickness, and multiple circular preforms can be formed in one process, increasing production efficiency by 15%-20% compared to the traditional square felt preparation process.

[0018] Comprehensive optimization of braking stability: During the braking process, the friction surface of the preform prepared by this invention always maintains a uniform contact state, which completely solves the problem of the friction surface switching between different material interfaces such as non-woven fabric layer and mesh tire layer during the friction process of traditional brake discs. This effectively eliminates unstable phenomena such as braking vibration and braking force fluctuation, and ensures reliable and stable braking performance. Attached Figure Description

[0019] Figure 1 This is a top view of the prefabricated structure of the present invention; Figure 2 This is a schematic diagram of the prefabricated structure of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1-Wrapping layer; 2-Sewing unit. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only a part of the embodiments of this application, not all of them. The specific embodiments described herein are only used to explain the invention and are not intended to limit the invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] like Figure 1 and 2 As shown, the present invention provides a technical solution: a method for preparing a low-cost reinforcing preform for a brake disc, comprising the following steps: S1. Preparation of the mold core and winding of the carbon fiber mesh; A TC4 titanium alloy annular mold core was selected. After the needle-punched carbon fiber mesh was wrapped around the surface of the mold core, it was temporarily fixed with polyimide high-temperature resistant wide paper tape. In this embodiment, the dimensions of the mold core are: outer diameter 139.8±0.1mm, inner diameter 119.7±0.05mm, and height 320.3±0.1mm. The surface of the mold core is anodized, with an oxide layer thickness of 6.2±0.1μm and a surface roughness Ra=0.8±0.05μm.

[0023] In this embodiment, the carbon fiber mesh has a width of 300.2±0.05mm and a surface density of 120.5±0.2g / m³. 2, Monofilament interlacing density: 21±0.5 strands / cm 2 The single filament diameter is 7.0±0.03μm, the winding speed is 4.8±0.1r / min, and a constant tension of 70.3±0.2N is applied throughout the winding process, with tension fluctuation ≤±0.3N, to ensure that the carbon fiber mesh is laid flat and has a fit of ≥99.2% with the inner core of the mold. The circumferential interface overlap length of the carbon fiber mesh is 35.2±0.05mm, and the overlap is parallel to the axis of the inner core of the mold with a gap ≤0.12mm.

[0024] In this embodiment, the dimensions of the polyimide high-temperature resistant wide paper tape are: 50.0±0.05mm×0.10±0.005mm, and the polyimide high-temperature resistant wide paper tape has a temperature resistance ≥120.5℃, a peel strength ≥1.8N / cm, a spacing of 80.0±0.5mm, and an edge alignment deviation ≤0.08mm.

[0025] S2, carbon fiber bundles are wound in a circular direction; Untwisted carbon fiber bundles of the same specifications as S1 carbon fiber mesh are arranged side by side along the inner core axis of the mold and wound circumferentially using a high-precision winding equipment. After winding, polyimide high-temperature resistant wide paper tape is used for temporary fixation. In this embodiment, the untwisted carbon fiber tow is specifically a T700 grade PAN-based untwisted carbon fiber tow with a tow width of 20.0±0.05mm, a thickness of 0.150±0.005mm, a breaking strength ≥5.2GPa, an elastic modulus ≥235±2GPa, a twist ≤5 twists / m, and a uniformity ≥98.5%. Fifteen rolls of untwisted carbon fiber filaments, each weighing 5.0±0.05kg and measuring 3200±50m in length, are arranged side-by-side along the inner core axis of the mold, with a spacing of 0.20±0.02mm and a parallel deviation of ≤0.05mm from the inner core axis. The high-precision winding equipment winds the fibers in a circumferential direction at a speed of 8.2±0.1r / min, applying a constant tension of 70.3±0.2N throughout the process, with tension fluctuation ≤±0.3N. The angle between the untwisted carbon fiber bundle and the carbon fiber mesh layer is 90.0±0.2°, with a fit of ≥99.3%. The mesh layer is covered to a coverage of ≥99.8%, forming a 0.150±0.005mm thick fiber bundle layer with a surface flatness Ra≤1.2±0.05μm.

[0026] The overlap length of the untwisted carbon fiber bundles is 35.2±0.05mm. At the overlap, an additional 1500±50mPa·s epoxy-type carbon fiber special adhesive is used for spot bonding, with a bonding amount of 0.02±0.002g / point and a spacing of 15±1mm. It is cured at 25℃ for 10±1min. When fixing with tape, the overlap misalignment is ≤0.03mm. Then, it is rolled with a 0.3±0.02MPa pressure roller for 3.0±0.1s. The entire winding process is protected with argon gas of ≥99.999% purity and nitrogen flow rate of 15±0.5L / min. The tension fluctuation monitored by the tension sensor is ≤0.3N.

[0027] S3, Second layer of carbon fiber mesh tire winding; On the surface of the S2 filament layer, a carbon fiber mesh of the same specification is wound according to the S1 parameters. After the winding is completed, it is temporarily fixed with polyimide high temperature resistant wide paper tape and rolled to ensure that the carbon fiber mesh adheres to the carbon fiber filament layer. In this embodiment, the winding speed is 4.8±0.1r / min, the tension is 70.3±0.2N, the fluctuation is ≤±0.3N, the overlap length of the carbon fiber mesh is 38.1±0.05mm, and the overlap with the bottom carbon fiber mesh is staggered by 180.0±0.5°. The rolling process involves rolling twice with a pressure roller of 0.3±0.02MPa at a speed of 2.5±0.05mm / s, with an interval of 1.5±0.1s, to ensure that the carbon fiber mesh and the untwisted carbon fiber bundle have a bonding degree of ≥99.3%.

[0028] S4. Alternately stack and wind to the target size; Repeat steps S2 to S3 to perform alternating layering and winding to obtain a semi-finished ring preform of the target size; In this embodiment, a layer of carbon fiber mesh and a layer of untwisted carbon fiber bundle form a stack. After each stack is completed, it is rolled according to parameters S3, with additional vacuum pressing. The vacuum degree is -0.095±0.002MPa, the temperature is 60±1℃, the time is 8±0.5min, and the pressure is 0.5±0.02MPa, ensuring that the interlayer gap is ≤0.01mm. The winding layer 1 outside the core of the mold is as follows. Figure 1 As shown; In S4, the ambient temperature is 25.0±0.5℃ and the humidity is 45.0±1.0%RH. For every 50.0±0.1mm increase in outer diameter, the overlap length increases by 3.0±0.05mm, with a maximum of ≤45.0±0.05mm. After every 3 layers are completed, the layer is allowed to stand for 5.0±0.1min. After every 10 layers are completed, the interlayer thickness is measured using a 10MHz ultrasonic thickness gauge with an accuracy of ±0.005mm, with a measurement point spacing of 20±1mm and ≥20 points. When the deviation exceeds ±0.02mm, adjust the parameters until the preform has an outer diameter of 380.0±0.05mm, an inner diameter of 145.0±0.05mm, a thickness of 180.0±0.1mm, and an outermost surface of untwisted carbon fiber bundle layer. The resulting semi-finished preform has a surface flatness Ra≤1.0±0.05μm, an outer diameter runout ≤0.3±0.02mm, an inner diameter runout ≤0.2±0.01mm, and an overall roundness ≤0.4±0.02mm.

[0029] S5, Z-direction stitching and demolding cutting; A high-precision CNC sewing machine is used, with carbon fiber thread as the suture thread. Each sewing unit 2 is inserted radially and perpendicularly into the outer edge of the semi-finished preform from one end, and then perpendicularly exits from the inner surface on the same side. The process is repeated from the same point in the opposite direction. Sewing unit 2 is as follows: Figure 2 As shown, after completing one row of stitches, move the position clockwise by 10.0±0.02mm and stitch again until the semi-finished preform is stitched. After stitching, use a CNC demolding device to demold, and then use a high-precision cutting device to cut to the target size to complete the preparation of the preform.

[0030] In this embodiment, suturing was performed at 25.0±0.5℃ and 45.0±1.0%RH. The suture needle was Φ1.00±0.01mm, with a needle tip angle of 30.0±0.5° and a corner radius of 0.10±0.01mm. The suture was a T700 grade untwisted carbon fiber bundle of the same specification as S1. A tension of 70.3±0.2N was applied throughout the process, with fluctuations ≤±0.3N. The puncture frequency was 120±5 times / min, and the suture feed speed was 8±0.2mm / s.

[0031] In this embodiment, a single stitching unit 2 is inserted radially and vertically from one end of the semi-finished preform at a distance of 8.0±0.05mm from the radial outer edge, at a speed of 2.0±0.05mm / s, and then vertically exits from the inner surface on the same side at a speed of 1.8±0.05mm / s. It then inserts and exits from the same point in the opposite direction, with a longitudinal length of 4.0±0.02mm and a stitch width of ≤0.30±0.01mm. The radial spacing between adjacent suture units 2 is 4.0±0.02mm. After completing one row of suture units 2, the unit moves clockwise by 10.0±0.02mm, for a total of 38 rows of suture units 2. The circumferential center distance is 10.0±0.02mm, and the suture density is 10 rows / 100mm. 2 Every 5 rows are inspected with an instrument with an accuracy of ±0.005mm, and a CCD vision system is used simultaneously to monitor the suture quality in real time.

[0032] In this embodiment, after suturing, the mixture is left to stand in the same environment for 20.0±0.5 min, and then dust is removed by blowing with argon gas of ≥99.999% purity at a pressure of 0.2±0.02 MPa and a speed of 10±1 mm / s for 3±0.5 min. In this embodiment, the demolding speed of the CNC demolding equipment is 5.0±0.1mm / min, the pressure is 0.8±0.05MPa, and the surface stress is monitored in real time to be ≤50±2MPa. After demolding, a high-precision cutting device with an accuracy of ±0.01mm is used to cut to a thickness of 30.0±0.02mm, with a cutting speed of 3.0±0.05mm / s, a diamond tool with HRC≥65, a rotation speed of 3000±50r / min, a cut flatness Ra≤1.0±0.05mm, and a perpendicularity deviation. The surface roughness is ≤0.03mm. After cutting, it is left to stand in the same environment for 15.0±0.5min to eliminate stress. Then, it is vacuum dried at 80±1℃ for 60±5min with a vacuum degree of -0.095±0.002MPa until the moisture content is ≤0.05±0.005%. Finally, it is polished with an 800±50 mesh diamond polishing wheel at a speed of 1500±50r / min and a pressure of 0.3±0.02MPa for 5±0.5min until the surface roughness Ra≤0.8±0.05μm.

[0033] Example 1: Preparation of a preform of an aircraft brake disc with dimensions of Φ380.0±0.05mm×Φ145.0±0.05mm×30.0±0.02mm, using T700 grade PAN-based untwisted carbon fiber tow. The steps are as follows: S1. Preparation of the mold core and winding of the carbon fiber mesh; The inner core is made of TC4 titanium alloy circular mold with an outer diameter of 139.8±0.1mm and an anodized surface of 6.2±0.1μm, Ra=0.8±0.05μm. A 300.2±0.05mm wide carbon fiber mesh is wound at 4.8±0.1r / min with an overlap of 35.2±0.05mm and fixed with a tension of 70.3±0.2N, achieving a fit of ≥99.2%.

[0034] S2, carbon fiber bundles are wound in a circular direction; 15 rolls of 12K untwisted carbon fiber filaments, 20.0±0.05mm wide, 70.3±0.2N tension, 8.2±0.1r / min winding, 90.0±0.2° included angle, coverage ≥99.8%; argon protection, new and old filaments overlap by 35.2±0.05mm and are glued and fixed.

[0035] S3, Second layer of carbon fiber mesh tire winding; Repeat step S1, with the carbon fiber mesh overlapped by 38.1±0.05mm, staggered by 180° from the first layer of carbon fiber mesh, and wound with a tension of 70.3±0.2N. After rolling, the fit is ≥99.3%.

[0036] S4. Alternately stack and wind to the target size; Repeat steps S2 to S3, rolling and vacuum pressing each layer at -0.095±0.002MPa, ambient temperature 25.0±0.5℃, 45.0±1.0%RH, until the outer diameter is 380.0±0.05mm, with the outermost layer being a carbon fiber bundle layer.

[0037] S5, Z-direction stitching and demolding cutting; 70.3±0.2N tension stitching, stitching unit 2 8.0±0.05mm from the edge, radial spacing 4.0±0.02mm, circumferential spacing 10.0±0.02mm; after stitching, let stand, remove dust, demold, 5.0±0.1mm / min, cut to 30.0±0.02mm, dry and polish to Ra≤0.8±0.05μm.

[0038] In this experimental example, the carbon fiber bundle is a T700 grade PAN-based fiber with a single filament of 7.0±0.02μm, modified with KH-550, with a contact angle of 65±1°. The entire process is controlled by PLC in a Class 1000 clean environment with precise tension / temperature control. The inner core circle runout of the mold is ≤0.01mm, and the oxide layer adhesion is ≥5B with HRC30±2.

[0039] The performance and process parameters of the preform in the experimental examples of this invention (hereinafter referred to as "the product of this invention") were compared with those of the preform produced by the traditional vertical needle punching process (hereinafter referred to as "the traditional product") and the carbon fiber preform disclosed in patent CN114645462A (hereinafter referred to as "the comparative patent product"). The specific data are shown in Table 1 below. All test samples used the same specification of carbon fiber raw materials and carbon / carbon composite material preparation process, and the testing standards followed the relevant industry standards for aerospace braking materials (HB7784-2020).

[0040] Table 1 Comparison of Performance and Process Parameters As shown in Table 1, the product in the experimental examples of this invention is superior to traditional products and comparative patented products in terms of structural integrity, mechanical properties, raw material utilization, braking stability, and production efficiency. Specifically, regarding the core braking stability indicator, the integrated "winding + stitching" structural design completely solves the problem of alternating friction surfaces in existing technologies, significantly reducing friction coefficient fluctuations and braking vibration rates. In terms of cost control, the near-net-shape forming process and multi-part simultaneous manufacturing capability significantly improve raw material utilization and production efficiency, achieving synergistic optimization of high performance and low cost, making it more suitable for large-scale applications in braking systems for aviation, high-end automobiles, and other industries.

[0041] It should be further noted that the accompanying drawings and embodiments of the present invention mainly describe the concept of the present invention. Based on this concept, some specific forms and arrangements of connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, under the premise that those skilled in the art understand the concept of the present invention, they can implement the above-mentioned specific forms and arrangements in a well-known manner.

[0042] When a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0043] The directional terms "inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself. The terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," or "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0044] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative descriptions used herein will be interpreted accordingly.

[0045] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, and "several" means one or more, unless otherwise explicitly specified.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0047] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the equivalents of the appended claims.

Claims

1. A method for preparing a low-cost reinforcing preform for a brake disc, characterized in that, Includes the following steps: S1. Preparation of the mold core and winding of the carbon fiber mesh; A TC4 titanium alloy annular mold core was selected. After the needle-punched carbon fiber mesh was wrapped around the surface of the mold core, it was temporarily fixed with polyimide high-temperature resistant wide paper tape. S2, carbon fiber bundles are wound in a circular direction; Untwisted carbon fiber bundles of the same specifications as S1 carbon fiber mesh are arranged side by side along the inner core axis of the mold and wound circumferentially using a high-precision winding equipment. After winding, polyimide high-temperature resistant wide paper tape is used for temporary fixation. S3, Second layer of carbon fiber mesh tire winding; On the surface of the S2 filament layer, a carbon fiber mesh of the same specification is wound according to the S1 parameters. After the winding is completed, it is temporarily fixed with polyimide high temperature resistant wide paper tape and rolled to ensure that the carbon fiber mesh adheres to the carbon fiber filament layer. S4. Alternately stack and wind to the target size; Repeat steps S2 to S3 to perform alternating layering and winding to obtain a semi-finished ring preform of the target size; S5, Z-direction stitching and demolding cutting; A high-precision CNC sewing machine is used, and carbon fiber thread is used for the sutures. Each suture unit is inserted radially and vertically into the outer edge of one end of the semi-finished preform, and then vertically out of the inner surface on the same side. Then, it is inserted and out in the opposite direction from the same point. After completing one row of sutures, the unit is moved clockwise by 10.0±0.02mm and sutured again until the semi-finished preform is sewn. After sewing, a CNC demolding device is used to demold the preform. After demolding, a high-precision cutting device is used to cut the preform to the target size, thus completing the preparation of the preform.

2. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 1, characterized in that, The dimensions of the mold core in S1 are: outer diameter 139.8±0.1mm, inner diameter 119.7±0.05mm, and height 320.3±0.1mm. The surface of the mold core is anodized, with an oxide layer thickness of 6.2±0.1μm and a surface roughness Ra=0.8±0.05μm.

3. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 2, characterized in that, In S1, the width of the carbon fiber mesh is 300.2±0.05mm, and the areal density is 120.5±0.2g / m³. 2, The monofilament interlacing density is 21±0.5 strands / cm. 2 The single filament diameter is 7.0±0.03μm, the winding speed is 4.8±0.1r / min, and a constant tension of 70.3±0.2N is applied throughout the winding process, with tension fluctuation ≤±0.3N, to ensure that the carbon fiber mesh is laid flat and has a fit of ≥99.2% with the inner core of the mold. The circumferential interface overlap length of the carbon fiber mesh is 35.2±0.05mm, and the overlap is parallel to the axis of the inner core of the mold with a gap ≤0.12mm.

4. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 3, characterized in that, In S1, the dimensions of the polyimide high-temperature resistant wide paper tape are: 50.0±0.05mm×0.10±0.005mm, and the polyimide high-temperature resistant wide paper tape has a temperature resistance ≥120.5℃, a peel strength ≥1.8N / cm, a spacing of 80.0±0.5mm, and an edge alignment deviation ≤0.08mm.

5. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 4, characterized in that, In S2, the untwisted carbon fiber tow is specifically a T700 grade PAN-based untwisted carbon fiber tow with a tow width of 20.0±0.05mm, a thickness of 0.150±0.005mm, a breaking strength ≥5.2GPa, an elastic modulus ≥235±2GPa, a twist ≤5 twists / m, and a uniformity ≥98.5%. Fifteen rolls of untwisted carbon fiber filaments, each weighing 5.0±0.05kg and measuring 3200±50m in length, are arranged side-by-side along the inner core axis of the mold, with a spacing of 0.20±0.02mm and a parallel deviation of ≤0.05mm from the inner core axis. The high-precision winding equipment winds the carbon fiber filaments circumferentially at a speed of 8.2±0.1 r / min, applying a constant tension of 70.3±0.2 N throughout the process, with tension fluctuation ≤±0.3 N. The angle between the untwisted carbon fiber filaments and the carbon fiber mesh layer is 90.0±0.2°, with a fit ≥99.3%. The mesh layer is covered to a coverage ≥99.8%, forming a filament layer with a thickness of 0.150±0.005 mm. The surface flatness Ra is ≤1.2±0.05 μm, and the overlap length of the untwisted carbon fiber filaments is 35.2±0.05 mm. At the filament overlap, apply epoxy-type carbon fiber special adhesive with a viscosity of 1500±50mPa·s in dots, with an application amount of 0.02±0.002g / dot and a spacing of 15±1mm. Cure at 25℃ for 10±1min. When fixing with tape, the overlap misalignment should be ≤0.03mm. Then roll with a pressure roller of 0.3±0.02MPa for 3.0±0.1s. The entire winding process is protected with argon gas of ≥99.999% purity and nitrogen gas flow rate of 15±0.5L / min. Tension sensor monitors the tension fluctuation to be ≤0.3N.

6. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 5, characterized in that, In S3, the winding speed is 4.8±0.1r / min, the tension is 70.3±0.2N, the fluctuation is ≤±0.3N, the carbon fiber mesh overlap length is 38.1±0.05mm, and the overlap with the bottom carbon fiber mesh is staggered by 180.0±0.5°. The rolling process involves rolling twice with a pressure roller of 0.3±0.02MPa at a speed of 2.5±0.05mm / s, with an interval of 1.5±0.1s, to ensure that the carbon fiber mesh and the untwisted carbon fiber bundle have a bonding degree of ≥99.3%.

7. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 6, characterized in that, In S4, a layer of carbon fiber mesh and a layer of untwisted carbon fiber bundles form a stack. After each stack is completed, it is rolled according to the parameters of S3, and an additional vacuum pressing is added. The vacuum degree is -0.095±0.002MPa, the temperature is 60±1℃, the time is 8±0.5min, and the pressure is 0.5±0.02MPa to ensure that the interlayer gap is ≤0.01mm. In S4, the ambient temperature is 25.0±0.5℃ and the humidity is 45.0±1.0%RH. For every 50.0±0.1mm increase in outer diameter, the overlap length increases by 3.0±0.05mm, with a maximum of ≤45.0±0.05mm. After every 3 layers are completed, the layer is allowed to stand for 5.0±0.1min. After every 10 layers are completed, the interlayer thickness is measured using a 10MHz ultrasonic thickness gauge with an accuracy of ±0.005mm, with a measurement point spacing of 20±1mm and ≥20 points. When the deviation exceeds ±0.02mm, adjust the parameters until the preform has an outer diameter of 380.0±0.05mm, an inner diameter of 145.0±0.05mm, a thickness of 180.0±0.1mm, and an outermost surface of untwisted carbon fiber bundle layer. The resulting semi-finished preform has a surface flatness Ra≤1.0±0.05μm, an outer diameter runout ≤0.3±0.02mm, an inner diameter runout ≤0.2±0.01mm, and an overall roundness ≤0.4±0.02mm.

8. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 7, characterized in that, In S5, suturing was performed at 25.0±0.5℃ and 45.0±1.0%RH. The suture needle was Φ1.00±0.01mm, with a needle tip angle of 30.0±0.5° and a corner radius of 0.10±0.01mm. The suture was T700 grade untwisted carbon fiber tow of the same specification as in S1. A tension of 70.3±0.2N was applied throughout the process, with fluctuations ≤±0.3N. The puncture frequency was 120±5 times / min, and the suture feed speed was 8±0.2mm / s.

9. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 8, characterized in that, In S5, a single stitching unit is inserted radially and vertically from one end of the semi-finished preform at a distance of 8.0±0.05mm from the radial outer edge, at a speed of 2.0±0.05mm / s, and then inserted and exited vertically from the inner surface on the same side at a speed of 1.8±0.05mm / s. The stitching unit is then inserted and exited from the same point in the opposite direction. The longitudinal length is 4.0±0.02mm, and the stitch width is ≤0.30±0.01mm. The radial spacing between adjacent suture units is 4.0±0.02mm. After completing one row of suture units, the unit moves clockwise by 10.0±0.02mm, for a total of 38 rows of suture units. The circumferential center distance is 10.0±0.02mm, and the suture density is 10 rows / 100mm. 2 Every 5 rows are inspected with an instrument with an accuracy of ±0.005mm, and a CCD vision system is used simultaneously to monitor the suture quality in real time.

10. The method for preparing a low-cost reinforcing preform for a brake disc according to claim 9, characterized in that, After suturing in S5, let it stand in the same environment for 20.0±0.5 min, and then blow it with argon gas with a purity ≥99.999%, pressure 0.2±0.02MPa, speed 10±1mm / s for 3±0.5 min to remove dust; The CNC demolding equipment has a demolding speed of 5.0±0.1mm / min, a pressure of 0.8±0.05MPa, and real-time surface stress monitoring of ≤50±2MPa. After demolding, a high-precision cutting device with an accuracy of ±0.01mm is used to cut to a thickness of 30.0±0.02mm at a cutting speed of 3.0±0.05mm / s, using diamond tools with HRC≥65 and a rotation speed of 3000±50r / min. The cut flatness Ra is ≤1.0±0.05mm, and the perpendicularity deviation is ≤0. The material is cut to 0.03mm. After cutting, it is left to stand in the same environment for 15.0±0.5min to eliminate stress. Then, it is vacuum dried at 80±1℃ for 60±5min with a vacuum degree of -0.095±0.002MPa until the moisture content is ≤0.05±0.005%. Finally, it is polished with an 800±50 grit diamond polishing wheel at a speed of 1500±50r / min and a pressure of 0.3±0.02MPa for 5±0.5min until the surface roughness Ra≤0.8±0.05μm.

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