Low-cost and high-performance brake ventilation disc, forming mold and forming method of low-cost and high-performance brake ventilation disc

Abstract

The invention belongs to the technical field of traffic equipment brake devices, and particularly discloses a low-cost and high-performance brake ventilation disc, a forming mold and a forming method.The brake ventilation disc comprises an annular integrated disc body which is composed of a composite fiber body and a silicon carbide ceramic layer wrapping the composite fiber body; the composite fiber body is formed by alternately laminating a mixture of a long-fiber plaid fabric prepreg and a chopped fiber, and an air duct, an assembly hole and a ventilation hole are formed in the disc body; the forming die is composed of a base plate, an inner die, a hole channel forming piece and an upper cover. According to the forming method, a near-net-shaped composite fiber body can be obtained through the forming mold, and then a target part can be obtained through machining, carbonization, ceramization and densification in sequence. According to the brake ventilation disc, the long fibers and the short fibers are combined together, so that the brake ventilation disc has excellent comprehensive mechanical properties, meanwhile, based on a specially-made forming mold, the production efficiency is greatly improved, the production cost is reduced, and large-scale production is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of traffic equipment brake devices, and in particular relates to a low-cost and high-performance brake ventilation disc, a molding die and a molding method thereof. Background Art

[0002] In the field of transportation equipment braking, with the rapid development of technology, the performance requirements for brake components are becoming more and more stringent. As a key braking device, the performance of the brake ventilated disc is directly related to driving safety and efficiency.

[0003] Among them, C / C-SiC composite materials have become a new generation of high-temperature structural materials with high attention, relying on many excellent physical properties, such as low density, high specific strength, high temperature resistance, oxidation resistance, and acid and alkali corrosion resistance, and are widely used in high-end fields such as aviation, aerospace, and weapons. In the field of brakes, this composite material overcomes the problems of large brake mass, low high-temperature strength, easy sticking to the disc during high-speed braking, and thermal decay of friction performance of metal materials. At the same time, it overcomes the problems of low static friction coefficient, easy oxidation at high temperature, and obvious decay of friction performance under wet conditions of C / C material brake materials. Therefore, it has become an inevitable trend to use C / C-SiC composite materials to prepare a new generation of brake ventilated discs.

[0004] However, there are currently two mainstream methods for preparing brake ventilated discs using C / C-SiC composite materials: one is chopped fiber molding + carbonization + melt siliconization process. Although the process seems simple, the fiber reinforcement phase uses short-sized discontinuous fibers, which greatly reduces the mechanical properties of the final disc and makes it difficult to withstand high-intensity braking impacts. In addition, the chopped fibers and resin powder are only randomly mixed mechanically. In the layer molding process, it is very easy to have uneven distribution of chopped fibers and powder. The mechanical properties of local fiber or powder aggregation areas and sparse areas are significantly different, which seriously affects the overall reliability and service life of the brake disc. The other is a three-dimensional needle-punched structure preform with a mesh tire + chemical vapor infiltration process + melt siliconization process. In this method, the production cost of the three-dimensional needle-punched structure preform with a mesh tire is high. Moreover, due to the complex structure of the preform and the uneven density of the needle, the chemical vapor infiltration deposition cycle is long, the efficiency is low, and the uniformity is poor. The material properties of different parts are uneven, which also buries many hidden dangers for the quality control of the brake disc.

[0005] Another example is the existing patent technology. The Chinese patent with announcement number CN110981518A proposes a carbon-ceramic composite brake disc and its preparation method. It attempts to use an injection needle to inject ceramic powder slurry into a three-dimensional needle-punched structure preform, and then combine it with a chemical vapor deposition process to create a carbon-ceramic composite brake disc. However, the disadvantage of this method is that the injection needle injection method requires extremely high operating precision and skills, and is extremely difficult to implement. It is not suitable for low-cost and fast mass industrial production. In addition, the injection needle can easily damage the preform fibers during the puncture process, destroy the integrity of the fiber structure, and weaken the mechanical properties of the material. In addition, the slurry is affected by factors such as injection pressure and fiber resistance, and is easily enriched near the injection hole, which leads to serious uneven distribution of components, large performance fluctuations in different parts of the brake disc, and no guarantee of braking stability and reliability. It is difficult to meet the current urgent needs for the coordinated development of high performance and low cost of brake ventilation discs.

[0006] In view of this, this invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a low-cost and high-performance brake ventilation disc, a molding mold and a molding method thereof, which are mainly used to solve the problems of uneven distribution during the molding of the mixed layer of chopped fibers and powder, and poor mechanical properties due to the lack of long fibers. At the same time, it solves the problems of long deposition cycle, poor composition uniformity and high cost faced in the preparation of brake ventilation discs by the mesh three-dimensional needle-punched structure preform + chemical vapor infiltration process.

[0008] The purpose of the present invention is to be solved by the following technical solutions:

[0009] In a first aspect, the present invention provides a low-cost, high-performance brake ventilated disc, comprising a disc body in an annular shape, wherein the disc body is composed of a composite fiber body and a silicon carbide ceramic layer wrapping the composite fiber body, and the disc body is an integrated structure;

[0010] Among them, a plurality of groups of air ducts in a circular array are arranged inside the disc body, each group of the air ducts includes 2 to 3 tapered bar holes arranged at intervals, and each of the tapered bar holes is distributed along the radial direction of the disc body; an assembly hole connected to the braking system is provided at the connection between any two adjacent groups of the air ducts located at the center of the disc body, and a plurality of ventilation holes are evenly opened on the surface of the disc body, and each of the ventilation holes vertically penetrates the corresponding air duct.

[0011] Further, the composite fiber body is formed by alternately laminating a mixture of long-fiber lattice cloth prepreg and short-cut fibers;

[0012] Wherein, the long fibers are T700-12K or T700-24K carbon yarns; and the size of the chopped fibers is 1 mm to 10 mm.

[0013] Furthermore, the fiber volume fraction of the composite fiber body is 35% to 65%; and the porosity of the silicon carbide ceramic layer is 2.5% to 6%.

[0014] In a second aspect, the present invention provides a molding die for the above-mentioned brake ventilation disc, comprising a molded chassis, a molded inner mold, a channel molding piece, and a molded upper cover matching the molded chassis;

[0015] The molded chassis is a cylindrical structure with a closed bottom, the inner diameter of the cylindrical structure matches the outer diameter of the disc body, a cylindrical boss is provided at the bottom center of the cylindrical structure, the outer diameter of the cylindrical boss matches the inner diameter of the disc body, a plurality of first insertion holes are provided at intervals along the circumferential direction on the cylindrical wall of the cylindrical structure, and the number and position of the first insertion holes match the air duct;

[0016] The molded inner mold is a disc structure, and a plurality of protrusions are evenly distributed along the radial direction on the outer ring wall of the disc structure, each of the protrusions is radially provided with a plurality of second insertion holes, the number, position and specification of the second insertion holes match the tapered strip holes, a first through hole is provided at the center of the disc structure, and the inner diameter of the first through hole matches the outer diameter of the cylindrical boss;

[0017] The channel forming member is a tapered member, which is inserted into the second insertion hole through the first insertion hole to form a tapered strip hole when in use;

[0018] The molded upper cover includes an outer ring wall and an inner ring wall with the same bottom and coaxiality, a heat conduction groove is provided between the outer ring wall and the inner ring wall, the outer diameter of the outer ring wall matches the inner diameter of the molded bottom plate, a second through hole is opened in the center of the molded upper cover, and the inner diameter of the second through hole matches the outer diameter of the cylindrical boss.

[0019] Furthermore, the ratio of the height of the inner cavity of the molded chassis to the axial height of the disk body is (3-5):1; the number of protrusions in the molded inner mold is the same as the number of air duct groups; the number of the duct forming parts is the same as the total number of tapered strip holes, and each duct forming part has a rounded corner on the edge that matches the tapered strip holes; the wall thickness of the molded chassis and the molded upper cover is 10mm-40mm.

[0020] In a third aspect, the present invention further provides a method for forming a brake ventilated disc, the method being based on the above-mentioned forming die and comprising the following steps:

[0021] Step 1: preparing materials required for the composite fiber body: including a mixture of a long fiber lattice cloth prepreg and short fiber;

[0022] Step 2, molding to prepare a composite fiber body: alternately stacking and mixing the long fiber lattice cloth prepreg and the short fiber mixture prepared in step 1, and pressing into a composite fiber body using the molding mold and the pressing machine;

[0023] Step 3, machining: grinding the composite fiber body prepared in step 2, and machining assembly holes and ventilation holes at corresponding positions on the composite fiber body;

[0024] Step 4, carbonization treatment: carbonizing the composite fiber body machined in step 3 to obtain a loose and porous composite fiber body;

[0025] Step 5, ceramic treatment: using a melt siliconization process to form a silicon carbide ceramic layer on the outside of the composite fiber body carbonized in step 4;

[0026] Step 6: Densification treatment: Densification treatment is performed on the brake ventilating disc ceramicized in step 5 to reduce the porosity of the silicon carbide ceramic layer.

[0027] Specifically, in step 1, the preparation process of the long fiber lattice cloth prepreg is as follows: first, T700-12K or T700-24K carbon yarn is used to weave it into a plain or twill lattice fiber cloth, the weaving grid width is 8mm to 20mm, and the fiber cloth thickness is 0.07mm to 0.21mm; then, anhydrous ethanol and phenolic resin are mixed in a mass ratio of (3 to 4): (1 to 1.5) to form a phenolic resin slurry; then, the plain or twill lattice fiber cloth is preheated to 50° C. to 80° C., and the phenolic resin slurry is evenly applied to obtain the long fiber lattice cloth prepreg;

[0028] Wherein, the mass proportion of phenolic resin in the long-fiber lattice cloth prepreg is 20% to 45%;

[0029] The preparation process of the chopped fiber mixture is as follows: graphite, silicon powder, silicon carbide powder, titanium carbide powder, phenolic resin powder and chopped fibers are uniformly mixed in a mass ratio of (0.5-3): (0.5-2.5): (0.5-2): (0.5-1.5): (1-6): (1-5) to obtain the chopped fiber mixture;

[0030] The chopped fibers are composed of fibers with sizes of 1 mm to 3 mm, 4 mm to 6 mm, and 7 mm to 10 mm in a mass ratio of (2 to 4): (2 to 4): (2 to 6).

[0031] In step 2, the specific process of preparing the composite fiber body by molding is as follows: first, the long-fiber lattice cloth prepreg is trimmed to adapt to the size of the molding mold; then, each layer of the long-fiber lattice cloth prepreg and a layer of the short-cut fiber mixture are stacked and pre-compacted once by a press, and the mass ratio of the two is (1-5): (1-4); until the total pre-compacted thickness is greater than the thickness of the finished product, the final pressing is performed and the mixture is demoulded after natural cooling;

[0032] During the last pressing, the molding die is preheated to 60°C to 100°C, and the parameters of the press are set as follows: pressure 45MPa to 75MPa, holding temperature 160°C to 210°C, and holding time 3h to 5h.

[0033] In step 4, the specific process of the carbonization treatment is: placing the machined composite fiber body in a heating furnace and heating it to 900°C~1000°C, requiring the vacuum degree in the furnace to be less than 0.001MPa, the heating rate to be 5°C / Min~15°C / Min, keeping warm for 1h~4h and then cooling to room temperature with the furnace.

[0034] In step 5, the specific steps of the ceramic treatment are as follows:

[0035] Step 5.1, uniformly mixing silicon powder, silicon carbide powder and iron powder in a mass ratio of (3.5-5.5):(4.5-3.5):(0.1-0.3) to obtain a ceramic raw material;

[0036] Step 5.2, placing the carbonized composite fiber body in step 4 into a crucible, and completely wrapping the composite fiber body with the ceramic raw material obtained in step 5.1;

[0037] Step 5.3, place the composite fiber body connected crucible treated in step 5.2 in a heating furnace, first heat it to 1500℃~1600℃, keep it warm for 1h~2h, then continue to heat it to 1600℃~1700℃, keep it warm for 1h~2h, then continue to heat it to 1700℃~1800℃, keep it warm for 1h~2h, and then cool it to room temperature with the furnace.

[0038] In step 6, the specific process of the densification treatment is: placing the ceramicized brake ventilation disc in a heating furnace and heating it to 1600° C. to 1800° C., keeping it warm for 2 h to 3 h, and then cooling it to room temperature with the furnace.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The brake ventilating disc provided by the present invention is composed of a composite fiber body (carbon fiber) composed of long fibers and short fibers alternately stacked from the inside to the outside, and a silicon carbide ceramic layer wrapping the composite fiber body. Since carbon fiber and silicon carbide have the characteristics of low density, high tensile strength, high temperature resistance, wear resistance, etc., the prepared brake ventilating disc has been verified to have a low density (2.0g / cm 3 ~2.35g / cm 3 ), high friction coefficient (0.31-0.43), good wear resistance (wear rate 0.35×10 - 7 cm 3 / (N·m)~0.55×10 -7 cm 3 / (N·m)) and other advantages. It has the advantage of not sticking when the temperature rises to 1300℃ during braking. Compared with the existing alloy brake ventilated disc, it can achieve a weight reduction of 30% to 55%, and the temperature resistance is improved from 1050℃ to 1300℃, thereby greatly improving the braking efficiency. In addition, compared with the existing process of prefabricated bodies containing mesh tires and three-dimensional needle-punched structures, the production cost of the brake ventilated disc is reduced by 30% to 40%, and the preparation time is increased by 35% to 55%.

[0041] 2. The molding die provided by the present invention can eliminate the complicated steps of preform shaping, and can realize the near-net-shape forming of the disc body and the air duct through the molded inner mold and the channel forming parts with rounded corners. The directly formed air duct rounded corners can improve the processing efficiency by 10% to 15% compared with the right-angled rounded corners. In addition, the molded chassis, the molded inner mold and the molded upper cover are all hollow structures, which can realize the weight reduction of the mold and the near-net-shape forming of the brake ventilation disc as a whole, and at the same time, it can avoid the central stress concentration deformation and cracking during the molding of the solid disc and maintain the uniformity of the heating of the brake ventilation disc surface during the molding process.

[0042] 3. The molding method provided by the present invention combines long and short fibers together and brings out their respective advantages. The long-fiber lattice cloth prepreg has extremely high strength and approximate isotropy in the radial direction due to the staggered stacking, which improves its bending strength (400MPa-500MPa); the mixture of chopped fibers improves the axial mechanical properties of the brake ventilation disc due to the random orientation of the fibers. In addition, the molding method provided by the present invention optimizes the ratio of phenolic resin slurry in the long-fiber lattice cloth prepreg, the ratio of the mixture of chopped fibers, and the ratio of short fibers of different sizes. Among them, the appropriate phenolic resin slurry in the long-fiber lattice cloth prepreg can not only avoid being squeezed out and lost during molding, but also provide sufficient interlayer bonding force during molding; the adaptation of the components in the mixture of chopped fibers will improve the density, strength, friction and wear performance of the brake ventilation disc; at the same time, the ratio of short fibers of different sizes can effectively improve the approximate isotropy and axial mechanical properties of the brake ventilation disc. The mixture of chopped fibers improves the comprehensive performance of the brake ventilated disc through multiple components. For example, graphite, silicon powder, and silicon carbide powder can improve its density (porosity 2.5% to 6%). Titanium carbide powder reacts to generate Ti during the molten siliconization process. 3 SiC 2 It can improve the wear resistance of the brake ventilated disc. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the present invention.

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 It is a schematic diagram of the overall structure of the brake ventilation disc of the present invention;

[0046] Figure 2 It is a schematic diagram of the internal structure of the brake ventilation disc of the present invention;

[0047] Figure 3 Schematic diagram of the fiber layer structure of the brake ventilated disc body of the present invention;

[0048] Figure 4 It is a schematic diagram of the structure of the lattice cloth prepreg (plain weave) of medium and long fibers of the present invention;

[0049] Figure 5 It is a schematic diagram of the structure of the molded chassis in the molding die of the present invention;

[0050] Figure 6It is a schematic diagram of the structure of the inner mold in the molding die of the present invention;

[0051] Figure 7 It is a schematic diagram of the structure of the channel forming part in the forming mold of the present invention;

[0052] Figure 8 It is a schematic diagram of the structure of the molded upper cover in the molding die of the present invention;

[0053] Fig. 9 It is a schematic diagram of the combined structure of the molded chassis, the molded inner mold, and the channel forming part in the present invention;

[0054] Fig.10 It is a schematic diagram of the combined structure of the molded chassis, the molded inner mold, the channel forming part, and the molded upper cover in the present invention;

[0055] Fig.11 The present invention is a process flow chart of the brake ventilation disc molding method.

[0056] in:

[0057] 1 is a disk body; 2 is an air duct; 3 is an assembly hole; 4 is a ventilation hole; 11 is a composite fiber body; 12 is a silicon carbide ceramic layer; 21 is a tapered strip hole; 111 is a long fiber lattice cloth prepreg; 112 is a mixture of short-cut fibers;

[0058] A is a molded chassis; B is a molded inner mold; C is a channel forming part; D is a molded upper cover; A1 is a cylindrical boss; A2 is a first insertion hole; B1 is a protrusion; B2 is a second insertion hole; B3 is a first through hole; D1 is an outer ring wall; D2 is an inner ring wall; D3 is a heat conduction groove; D4 is a second through hole. DETAILED DESCRIPTION

[0059] Here, exemplary embodiments will be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention as detailed in the appended claims.

[0060] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0061] Example 1

[0062] See also Figures 1 to 4The brake ventilation disc provided in Example 1 of the present invention has the advantages of low cost and high performance. Its overall disc body structure is annular, and its outer dimensions are φ420mm×φ220mm×40mm. The interior of the disc body is supported by a composite fiber body 11 with a fiber volume fraction of 55% as the core, and the outer layer is tightly wrapped with a silicon carbide ceramic layer 12 with a porosity of 2.9%. Through the synergistic effect of the two, and the fact that the entire disc body 1 is an integrated design, the strength and stability of the main structure of the brake ventilation disc are guaranteed.

[0063] like Figure 1 , 2 As shown, in the embodiment of the present invention, 8 to 12 groups of circular array air ducts are arranged inside the disc body 1, and each group of air ducts 2 includes 2 to 3 tapered bar holes 21 arranged at intervals, and each tapered bar hole 21 is distributed along the radial direction of the disc body 1. Taking this embodiment as an example, the air ducts 2 are arranged in 10 groups, and each group is equipped with 3 tapered bar holes 21 with reasonable intervals. This configuration has been repeatedly verified and can greatly improve the heat dissipation and ventilation efficiency. In addition, an assembly hole 3 is provided at the connection between any two adjacent groups of air ducts 2 located at the center of the disc body 1. The specifications of the assembly hole 3 can be set according to the connector. For example, in this embodiment, the number of assembly holes 3 is determined to be 10, and the aperture of each assembly hole 3 is 6mm, which ensures the accuracy and reliability of the connection with the brake system. In addition, 128 to 196 ventilation holes 4 are evenly opened on the surface of the disc body 1, and every 16 ventilation holes 4 form a group, all of which vertically penetrate the corresponding air duct 2 to form an efficient ventilation network. In this embodiment, the number of ventilation holes 4 is set to 160 according to the number of groups of air ducts 2. It should be emphasized that, taking into account different braking scenarios and system adaptation requirements, the specifications and quantity of the air duct 2, assembly holes 3 and ventilation holes 4 on the brake ventilation disc can be set according to actual working conditions, and the present invention does not make specific limitations.

[0064] like Figure 3 , 4 As shown in the embodiment of the present invention, the composite fiber body 11 inside the disk body 1 is formed by alternately stacking long fiber lattice cloth prepreg 111 and short fiber mixture 112. The long fiber lattice cloth prepreg 111 has its own unique weaving structure (such as Figure 4 As shown in the figure, the composite fiber body 11 has advantages such as high strength in the radial direction and good load-bearing capacity, while the mixture 112 of chopped fibers can make up for the uneven distribution of mechanical properties of long fibers in the axial direction due to the random orientation of the fibers, making the performance of the composite fiber body 11 more balanced and coordinated in all directions. When the two are combined in the form of alternating layers, their advantages complement each other and synergize to create a composite fiber body 11 with excellent performance, laying a solid material foundation for the disc body 1 to cope with complex stress conditions and achieve stable and reliable braking functions during braking.

[0065] As Figures 5 to 10 shown, the embodiment of the present invention further provides a forming die for the above-mentioned brake ventilation disc. The forming die is composed of a die-pressing chassis A, a die-pressing inner mold B, a pore-forming part C, and a die-pressing upper cover D that matches the die-pressing chassis A. After assembly, its shape and effect are as Fig. 9 、 10 shown. Through this forming die and a press, the prepreg 111 of the long-fiber lattice cloth and the mixture 112 of the chopped fibers can be directly pressed into a near-net-shaped composite fiber body 11 in the die, improving the efficiency. The specific dimensions of each component in the forming die can be customized according to the actual specifications of the brake ventilation disc to be formed, and the present invention does not make specific limitations.

[0066] Specifically, the die-pressing chassis A has a cylindrical structure with a closed bottom. The wall thickness of the cylindrical structure is 30 mm. The inner diameter of the cylindrical structure matches the outer diameter of the disc body 1, and the height of the inner cavity of the die-pressing chassis A is 3.5 times the axial height of the disc body 1, so that the materials required for the formation of the disc body 1 can be completely placed in the inner cavity of the die-pressing chassis A, and at the same time, an extrusion space is left. A cylindrical boss A1 is provided at the center of the bottom of the cylindrical structure. The outer diameter of the cylindrical boss A1 matches the inner diameter of the disc body 1. Ten first mounting holes A2 are circumferentially spaced along the circumferential direction of the cylindrical wall of the cylindrical structure, and the positions of the first mounting holes A2 match the air ducts 2. The die-pressing chassis A is as Figure 5 shown.

[0067] As Figure 5 shown, the die-pressing inner mold B has a disc structure, and ten protruding parts B1 are evenly distributed along the radial direction on the outer ring wall of the disc structure. Each protruding part B1 is provided with three second mounting holes B2 along the radial direction. The positions and specifications of the second mounting holes B2 match the tapered strip holes 21. A first through hole B3 is provided at the center of the disc structure. The inner diameter of the first through hole B3 matches the outer diameter of the cylindrical boss A

[0068] As Figure 7 shown, the pore-forming part C is a tapered part, and the number thereof is the same as the total number of the tapered strip holes 21. A fillet with an R4 is provided at the edge of each pore-forming part C. During use, the pore-forming part C is inserted into the second mounting hole B2 through the first mounting hole A2 to form the tapered strip hole 21. Since a fillet is provided at the edge of each pore-forming part C, the finally formed tapered strip hole 21 has a fillet, and no subsequent processing is required for the fillet.

[0069] As Figure 8As shown, the molded upper cover D is a revolving body structure with a wall thickness of 30 mm, and specifically includes an outer ring wall D1 and an inner ring wall D2 that are coaxial with the same bottom. A heat conduction groove D3 is provided between the outer ring wall D1 and the inner ring wall D2. The outer diameter of the outer ring wall D1 matches the inner diameter of the molded chassis A. A second through hole D4 is opened in the center of the molded upper cover D, and the inner diameter of the second through hole D4 matches the outer diameter of the cylindrical boss A1.

[0070] like Fig.11 As shown, the present invention also provides a molding method for the above-mentioned brake ventilation disc, which is based on the above-mentioned molding die and specifically includes the following process:

[0071] 1) Materials required for preparing the composite fiber body 11: including a long fiber lattice cloth prepreg 111 and a mixture 112 of chopped fibers;

[0072] The preparation process of the long-fiber lattice cloth prepreg 111 is as follows: first, T700-24K carbon yarn is used to weave a plain lattice fiber cloth at 0° and 90°, with a weaving width of 12 mm and a fiber cloth thickness of 0.17 mm; then, anhydrous ethanol and phenolic resin are mixed in a mass ratio of 3.5:1 to form a phenolic resin slurry; then, the plain lattice fiber cloth is preheated to 70°C, and the phenolic resin slurry is evenly applied (the mass proportion of the phenolic resin in the long-fiber lattice cloth prepreg 111 is 40%), so as to obtain the long-fiber lattice cloth prepreg 111;

[0073] The preparation process of the chopped fiber mixture 112 is as follows: using a dry mixing process, graphite, silicon powder, silicon carbide powder, titanium carbide powder, phenolic resin powder and chopped fibers (the chopped fibers are composed of 3 mm, 5 mm, and 8 mm in a mass ratio of 2.5:2.5:5) are uniformly mixed in a mass ratio of 0.9:0.8:0.6:1.2:2.5:4 to obtain the chopped fiber mixture 112;

[0074] 2) Step 2, molding to prepare the composite fiber body 11: the long fiber lattice cloth prepreg 111 and the short fiber mixture 112 prepared in step 1) are alternately stacked and mixed, and pressed into the composite fiber body 11 using the above-mentioned molding mold and pressing machine;

[0075] Specifically, the long-fiber lattice cloth prepreg 111 is first trimmed to fit the size of the molding mold; then, each layer of the long-fiber lattice cloth prepreg 111 and a layer of the short-cut fiber mixture 112 are stacked and pre-compacted once by a press, and the mass ratio of the two is 2.5:1, until the total pre-compacted thickness is slightly greater than the thickness of the finished product; finally, the mold is demoulded after natural cooling;

[0076] In the last pressing, the forming mold was preheated to 75°C, and the parameters of the press were set as follows: pressure 60MPa, holding temperature 180°C, and holding time 3.5h;

[0077] 3) Machining: grinding the composite fiber body 11 prepared in step 2), and machining the assembly holes 3 and ventilation holes 4 at corresponding positions on the composite fiber body 11;

[0078] 4) Carbonization treatment: Carbonization treatment is performed on the composite fiber body 11 after machining in step 3) to obtain a loose and porous composite fiber body 11;

[0079] Specifically, the machined composite fiber body 11 is placed in a heating furnace and heated to 950° C., the vacuum degree in the furnace is required to be less than 0.001 MPa, the heating rate is 10° C. / Min, and after being kept warm for 2.5 hours (to carbonize the phenolic resin in the composite fiber body 11), the composite fiber body 11 is cooled to room temperature along with the furnace;

[0080] 5) Ceramic treatment: using a melt siliconization process to form a silicon carbide ceramic layer 12 on the outside of the composite fiber body 11 carbonized in step 4);

[0081] The specific steps of ceramic treatment are as follows:

[0082] 5.1) uniformly mixing silicon powder, silicon carbide powder and iron powder in a mass ratio of 4:4:0.2 to obtain a ceramic raw material;

[0083] 5.2) placing the carbonized composite fiber body 11 in step 4) into a crucible, and completely wrapping the composite fiber body 11 with the ceramic raw material obtained in step 5.1;

[0084] 5.3) placing the composite fiber body 11 connected to the crucible after the treatment in step 5.2) in a heating furnace, first heating to 1550° C., keeping the temperature for 1.5 hours, then heating to 1650° C., keeping the temperature for 1.5 hours, then heating to 1750° C., keeping the temperature for 1.5 hours (step heating promotes the reaction of molten silicon to form an external silicon carbide ceramic layer), and then cooling to room temperature with the furnace;

[0085] 6) Densification treatment: Densification treatment is performed on the brake ventilated disc that has been ceramicized in step 5) to reduce the porosity of the silicon carbide ceramic layer 12;

[0086] The specific process of the densification treatment is: place the completed ceramicized brake ventilation disc in a heating furnace and heat it to 1700°C, keep it warm for 2.5 hours, and then cool it to room temperature with the furnace to obtain the target brake ventilation disc.

[0087] To further verify the efficacy of the present invention, the inventor conducted the following tests on the brake ventilated disc prepared in Example 1: The execution standard for density detection is: GB / T 2997-2000, fine ceramic density and apparent porosity detection, and other tests. The test results show that the density of the brake ventilated disc obtained in this Example 1 is 2.05 g / cm 3 , the porosity is 2.8%, the friction coefficient is 0.32 - 0.43, the wear rate is 0.52×10 -7 cm 3 / (N·m), the flexural strength is 410 MPa, the weight is reduced by 40%, the comprehensive cost is reduced by 35%, the preparation efficiency is increased by 45%, and the maximum brake temperature resistance is 1300 °C, thereby greatly improving the brake efficiency.

[0088] Example 2

[0089] The target brake ventilated disc prepared in this example has the same specifications as those in Example 1, and its preparation method is also based on the molding die shown in Example 1. The specific preparation process is as follows:

[0090] 1) Prepare the materials required for the composite fiber body 11: including the grid cloth prepreg 111 of long fibers and the mixture 112 of chopped fibers;

[0091] Among them, the preparation process of the grid cloth prepreg 111 of long fibers is as follows: First, use T700-12K carbon yarn, and braid it into a twill grid fiber cloth at 0° and 45°, with a braided grid width of 8 mm and a fiber cloth thickness of 0.07 mm; then use anhydrous ethanol and phenolic resin mixed in a mass ratio of 4:1.5 to form a phenolic resin slurry; then preheat the twill grid fiber cloth to 50 °C and evenly apply the phenolic resin slurry (the mass ratio of phenolic resin in the grid cloth prepreg 111 of long fibers is 20%), and the grid cloth prepreg 111 of long fibers is obtained;

[0092] The preparation process of the mixture 112 of chopped fibers is as follows: Using a dry mixing process, evenly mix graphite, silicon powder, silicon carbide powder, titanium carbide powder, phenolic resin powder, and chopped fibers (the chopped fibers are composed of 2 mm, 4 mm, and 10 mm in a mass ratio of 2:2:2) in a mass ratio of 0.5:0.5:2:1.5:6:5, and the mixture 112 of chopped fibers is obtained;

[0093] 2) Step 2, mold pressing to prepare the composite fiber body 11: Alternately stack and mix the grid cloth prepreg 111 of long fibers and the mixture 112 of chopped fibers prepared in step 1), and use the above molding die and press to press into the composite fiber body 11, and the fiber volume fraction of the composite fiber body 11 is 35%;

[0094] Specifically, the long-fiber lattice cloth prepreg 111 is first trimmed to fit the size of the molding mold; then, each layer of the long-fiber lattice cloth prepreg 111 and a layer of the chopped fiber mixture 112 are stacked and pre-compacted once by a press, and the mass ratio of the two is 1:1, until the total pre-compacted thickness is slightly greater than the thickness of the finished product; finally, the mold is demoulded after natural cooling;

[0095] In the last pressing, the forming mold was preheated to 60°C, and the parameters of the press were set as follows: pressure 75MPa, holding temperature 160°C, and holding time 5h;

[0096] 3) Machining: grinding the composite fiber body 11 prepared in step 2), and machining the assembly holes 3 and ventilation holes 4 at corresponding positions on the composite fiber body 11;

[0097] 4) Carbonization treatment: Carbonization treatment is performed on the composite fiber body 11 after machining in step 3) to obtain a loose and porous composite fiber body 11;

[0098] Specifically, the machined composite fiber body 11 is placed in a heating furnace and heated to 900° C., the vacuum degree in the furnace is required to be less than 0.001 MPa, the heating rate is 5° C. / Min, and after being kept warm for 4 hours (to carbonize the phenolic resin in the composite fiber body 11), the composite fiber body 11 is cooled to room temperature along with the furnace;

[0099] 5) Ceramic treatment: using a melt siliconization process to form a silicon carbide ceramic layer 12 on the outside of the composite fiber body 11 carbonized in step 4);

[0100] The specific steps of ceramic treatment are as follows:

[0101] 5.1) uniformly mixing silicon powder, silicon carbide powder and iron powder in a mass ratio of 3.5:4.5:0.1 to obtain a ceramic raw material;

[0102] 5.2) placing the carbonized composite fiber body 11 in step 4) into a crucible, and completely wrapping the composite fiber body 11 with the ceramic raw material obtained in step 5.1;

[0103] 5.3) placing the composite fiber body 11 connected to the crucible after the treatment in step 5.2) in a heating furnace, first heating it to 1600° C., keeping it at that temperature for 1 hour, then heating it to 1700° C., keeping it at that temperature for 1 hour, then heating it to 1800° C., keeping it at that temperature for 1 hour (step heating promotes the reaction of molten silicon to form an external silicon carbide ceramic layer), and then cooling it to room temperature with the furnace;

[0104] 6) Densification treatment: Densification treatment is performed on the brake ventilated disc that has been ceramicized in step 5) to reduce the porosity of the silicon carbide ceramic layer 12;

[0105] The specific process of the densification treatment is: place the completed ceramicized brake ventilation disc in a heating furnace and heat it to 1600°C, keep it warm for 3 hours, and then cool it to room temperature with the furnace to obtain the target brake ventilation disc.

[0106] In order to further verify the efficacy of the present invention, the inventors conducted the following tests on the brake ventilated disc prepared in Example 2: density test execution standard: GB / T 2997-2000, fine ceramic density and apparent porosity test and other tests. The test results show that the density of the brake ventilated disc obtained in Example 2 is 2.25g / cm 3 , porosity is 5.8%, friction coefficient is 0.35~0.42, wear rate is 0.35×10 -7 cm 3 / (N·m), flexural strength 490MPa.

[0107] Example 3

[0108] The target brake ventilated disc prepared in this embodiment has the same specifications as that of embodiment 1, and its preparation method is also based on the molding die shown in embodiment 1. The specific preparation process is as follows:

[0109] 1) Materials required for preparing the composite fiber body 11: including a long fiber lattice cloth prepreg 111 and a mixture 112 of chopped fibers;

[0110] The preparation process of the long-fiber lattice cloth prepreg 111 is as follows: first, T700-12K carbon yarn is used to weave a plain lattice fiber cloth at 0° and 90°, with a weaving width of 20 mm and a fiber cloth thickness of 0.21 mm; then, anhydrous ethanol and phenolic resin are mixed in a mass ratio of 3:1 to form a phenolic resin slurry; then, the twill lattice fiber cloth is preheated to 80°C, and the phenolic resin slurry is evenly applied (the mass proportion of the phenolic resin in the long-fiber lattice cloth prepreg 111 is 45%), so as to obtain the long-fiber lattice cloth prepreg 111;

[0111] The preparation process of the chopped fiber mixture 112 is as follows: using a dry mixing process, graphite, silicon powder, silicon carbide powder, titanium carbide powder, phenolic resin powder and chopped fibers (the chopped fibers are composed of 1 mm, 6 mm, and 9 mm in a mass ratio of 4:4:6) are uniformly mixed in a mass ratio of 3:2.5:0.5:0.5:1:1 to obtain the chopped fiber mixture 112;

[0112] 2) Step 2, molding to prepare a composite fiber body 11: the long fiber lattice cloth prepreg 111 and the short fiber mixture 112 prepared in step 1) are alternately stacked and mixed, and pressed into a composite fiber body 11 using the above-mentioned molding die and pressing machine, wherein the fiber volume fraction of the composite fiber body 11 is 65%;

[0113] Specifically, the long-fiber lattice cloth prepreg 111 is first trimmed to fit the size of the molding mold; then, each layer of the long-fiber lattice cloth prepreg 111 and a layer of the chopped fiber mixture 112 are stacked and pre-compacted once by a press, and the mass ratio of the two is 5:4, until the total pre-compacted thickness is slightly greater than the thickness of the finished product; finally, the mold is demoulded after natural cooling;

[0114] In the last pressing, the forming mold was preheated to 100°C, and the parameters of the press were set as follows: pressure 45MPa, holding temperature 210°C, and holding time 3h;

[0115] 3) Machining: grinding the composite fiber body 11 prepared in step 2), and machining the assembly holes 3 and ventilation holes 4 at corresponding positions on the composite fiber body 11;

[0116] 4) Carbonization treatment: Carbonization treatment is performed on the composite fiber body 11 after machining in step 3) to obtain a loose and porous composite fiber body 11;

[0117] Specifically, the machined composite fiber body 11 is placed in a heating furnace and heated to 1000° C., the vacuum degree in the furnace is required to be less than 0.001 MPa, the heating rate is 15° C. / Min, and after being kept warm for 1 hour (to carbonize the phenolic resin in the composite fiber body 11), it is cooled to room temperature along with the furnace;

[0118] 5) Ceramic treatment: using a melt siliconization process to form a silicon carbide ceramic layer 12 on the outside of the composite fiber body 11 carbonized in step 4);

[0119] The specific steps of ceramic treatment are as follows:

[0120] 5.1) uniformly mixing silicon powder, silicon carbide powder and iron powder in a mass ratio of 5.5:3.5:0.3 to obtain a ceramic raw material;

[0121] 5.2) placing the carbonized composite fiber body 11 in step 4) into a crucible, and completely wrapping the composite fiber body 11 with the ceramic raw material obtained in step 5.1;

[0122] 5.3) placing the composite fiber body 11 connected to the crucible after the treatment in step 5.2) in a heating furnace, first heating it to 1500° C., keeping it at that temperature for 2 hours, then heating it to 1600° C., keeping it at that temperature for 2 hours, then heating it to 1700° C., keeping it at that temperature for 2 hours (step heating promotes the reaction of molten silicon to form an external silicon carbide ceramic layer), and then cooling it to room temperature with the furnace;

[0123] 6) Densification treatment: Densification treatment is performed on the brake ventilated disc that has been ceramicized in step 5) to reduce the porosity of the silicon carbide ceramic layer 12;

[0124] The specific process of the densification treatment is: place the completed ceramicized brake ventilation disc in a heating furnace and heat it to 1800°C, keep it warm for 2 hours, and then cool it to room temperature with the furnace to obtain the target brake ventilation disc.

[0125] In order to further verify the efficacy of the present invention, the inventors conducted the following tests on the brake ventilated disc prepared in Example 3: density test execution standard: GB / T 2997-2000, fine ceramic density and apparent porosity test and other tests. The test results show that the density of the brake ventilated disc obtained in Example 3 is 2.1g / cm 3 , porosity is 3.6%, friction coefficient is 0.31~0.38, wear rate is 0.41×10 -7 cm 3 / (N·m), flexural strength 455MPa.

[0126] Comparative Example 1

[0127] The target brake ventilating disc prepared in this comparative example has the same specifications as that of Example 1, and its preparation method is also based on the molding mold shown in Example 1. The only difference between its preparation process and that of Example 1 is step 1), and the other steps are exactly the same. Specifically, in this comparative example 1, the preparation process of the chopped fiber mixture 112 is as follows: using a dry mixing process, graphite, silicon powder, silicon carbide powder, titanium carbide powder, phenolic resin powder and chopped fibers (chopped fibers are composed of 3mm, 5mm, and 8mm in a mass ratio of 2.5:2.5:5) are uniformly mixed in a mass ratio of 0.5:0.5:1:1:5:2, and the chopped fiber mixture 112 is obtained. It should be noted that the chopped fibers in this comparative example are composed of 3mm, 5mm, and 8mm in size, but the ratio of the three is 1:1:8, that is, it is not within the required ratio of (2-4): (2-4): (2-6) of the chopped fibers.

[0128] The brake ventilated disc finally obtained in comparative example 1 was tested, and its density was only 1.93 g / cm3, the porosity was as high as 8.9%, the friction coefficient was only 0.22-0.25, and the wear rate was as high as 0.82×10 -5 cm 3 / (N·m), and the bending strength is only 280MPa, that is, the performance of the brake ventilated disc obtained in the comparative example is significantly reduced in all aspects.

[0129] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0130] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A low-cost, high-performance brake ventilated disc, characterized in that: The invention comprises a disk body (1) in the shape of an annulus, wherein the disk body (1) is composed of a composite fiber body (11) and a silicon carbide ceramic layer (12) wrapping the composite fiber body (11), and the disk body (1) is an integrated structure; A plurality of groups of air ducts (2) are arranged in a circular array inside the disk body (1), each group of the air ducts (2) comprises 2 to 3 tapered strip holes (21) arranged at intervals, and each of the tapered strip holes (21) is distributed along the radial direction of the disk body (1); an assembly hole (3) connected to the brake system is provided at the connection between any two adjacent groups of the air ducts (2) located at the center of the disk body (1), and a plurality of ventilation holes (4) are evenly opened on the surface of the disk body (1), and each of the ventilation holes (4) vertically penetrates the corresponding air duct (2).

2. The brake ventilated disc according to claim 1, characterized in that: The composite fiber body (11) is formed by alternately laminating long fiber lattice cloth prepreg (111) and short fiber mixture (112); Wherein, the long fibers are T700-12K or T700-24K carbon yarns; and the size of the chopped fibers is 1 mm to 10 mm.

3. The brake ventilated disc according to claim 1, characterized in that: The fiber volume fraction of the composite fiber body (11) is 35% to 65%; and the porosity of the silicon carbide ceramic layer (12) is 2.5% to 6%.

4. A molding die for a brake ventilated disc as claimed in any one of claims 1 to 3, characterized in that: It comprises a molded chassis (A), a molded inner mold (B), a channel forming part (C) and a molded upper cover (D) matching the molded chassis (A); The molded chassis (A) is a cylindrical structure with a closed bottom, the inner diameter of the cylindrical structure matches the outer diameter of the disc body (1), a cylindrical boss (A1) is arranged at the bottom center of the cylindrical structure, the outer diameter of the cylindrical boss (A1) matches the inner diameter of the disc body (1), a plurality of first insertion holes (A2) are arranged at intervals along the circumferential direction on the cylindrical wall of the cylindrical structure, and the number and position of the first insertion holes (A2) match the air duct (2); The molded inner mold (B) is in a disc structure, and a plurality of protrusions (B1) are evenly distributed along the radial direction on the outer ring wall of the disc structure, and each of the protrusions (B1) is provided with a plurality of second insertion holes (B2) along the radial direction, and the number, position and specification of the second insertion holes (B2) match those of the tapered strip holes (21); a first through hole (B3) is provided at the center of the disc structure, and the inner diameter of the first through hole (B3) matches the outer diameter of the cylindrical boss (A1); The channel forming member (C) is a tapered member, which is inserted into the second insertion hole (B2) through the first insertion hole (A2) to form a tapered strip hole (21) when in use; The molded upper cover (D) comprises an outer ring wall (D1) and an inner ring wall (D2) which are coaxial and have the same bottom. A heat conduction groove (D3) is provided between the outer ring wall (D1) and the inner ring wall (D2). The outer diameter of the outer ring wall (D1) matches the inner diameter of the molded bottom plate (A). A second through hole (D4) is provided at the center of the molded upper cover (D). The inner diameter of the second through hole (D4) matches the outer diameter of the cylindrical boss (A1).

5. The forming die of the brake ventilating disc according to claim 4, characterized in that: The ratio of the height of the inner cavity of the molded chassis (A) to the axial height of the chassis body (1) is (3-5):1; the number of the protrusions (B1) in the molded inner mold (B) is the same as the number of groups of air ducts (2); the number of the duct forming parts (C) is the same as the total number of the tapered strip holes (21), and the edge of each duct forming part (C) is provided with a rounded corner matching the tapered strip holes (21); the wall thickness of the molded chassis (A) and the molded upper cover (D) is 10 mm to 40 mm.

6. A method for forming a brake ventilated disc according to any one of claims 1 to 3, characterized in that: The molding method is based on the molding die according to claim 4 or 5, comprising the following steps: Step 1: preparing materials required for the composite fiber body (11): comprising a long fiber lattice cloth prepreg (111) and a mixture of short-cut fibers (112); Step 2, molding to prepare a composite fiber body (11): alternately stacking and mixing the long fiber lattice cloth prepreg (111) and the short fiber mixture (112) prepared in step 1, and pressing them into a composite fiber body (11) using the molding mold and the pressing machine; Step 3, machining: grinding the composite fiber body (11) prepared in step 2, and machining the assembly holes (3) and ventilation holes (4) at corresponding positions on the composite fiber body (11); Step 4, carbonization treatment: performing carbonization treatment on the composite fiber body (11) machined in step 3 to obtain a loose and porous composite fiber body (11); Step 5, ceramic treatment: using a melt siliconization process to form a silicon carbide ceramic layer (12) on the outside of the composite fiber body (11) carbonized in step 4; Step 6: Densification treatment: Densification treatment is performed on the brake ventilation disc ceramicized in step 5 to reduce the porosity of the silicon carbide ceramic layer (12).

7. The method for forming a brake ventilated disc according to claim 6, characterized in that: In step 1, the preparation process of the long-fiber lattice cloth prepreg (111) is as follows: first, T700-12K or T700-24K carbon yarn is used to weave it into a plain or twill lattice fiber cloth; then, anhydrous ethanol and phenolic resin are mixed in a mass ratio of (3-4): (1-1.5) to form a phenolic resin slurry; then, the plain or twill lattice fiber cloth is preheated to 50° C. to 80° C., and the phenolic resin slurry is evenly applied to obtain the long-fiber lattice cloth prepreg (111); The mass proportion of the phenolic resin in the long-fiber lattice cloth prepreg (111) is 20% to 45%; The preparation process of the chopped fiber mixture (112) is as follows: graphite, silicon powder, silicon carbide powder, titanium carbide powder, phenolic resin powder and chopped fibers are uniformly mixed in a mass ratio of (0.5-3): (0.5-2.5): (0.5-2): (0.5-1.5): (1-6): (1-5) to obtain the chopped fiber mixture (112); The chopped fibers are composed of fibers with sizes of 1 mm to 3 mm, 4 mm to 6 mm, and 7 mm to 10 mm in a mass ratio of (2 to 4): (2 to 4): (2 to 6).

8. The method for forming a brake ventilated disc according to claim 6, characterized in that: In step 2, the specific process of preparing the composite fiber body (11) by molding is as follows: first, the long-fiber lattice cloth prepreg (111) is trimmed to fit the size of the molding mold; then, after each stacking of a layer of the long-fiber lattice cloth prepreg (111) and a layer of the short-fiber mixture (112), they are pre-compacted once by a press, and the mass ratio of the two is (1 to 5): (1 to 4); until the total pre-compacted thickness is greater than the thickness of the finished product, a final pressing is performed and the mixture is demoulded after natural cooling; During the last pressing, the molding die is preheated to 60°C to 100°C, and the parameters of the press are set as follows: pressure 45MPa to 75MPa, holding temperature 160°C to 210°C, and holding time 3h to 5h.

9. The method for forming a brake ventilated disc according to claim 6, characterized in that: In step 4, the specific process of the carbonization treatment is: placing the machined composite fiber body (11) in a heating furnace and heating it to 900°C to 1000°C, requiring the vacuum degree in the furnace to be less than 0.001MPa, heating rate 5°C / Min to 15°C / Min, keeping the temperature for 1h to 4h, and then cooling it to room temperature with the furnace; In step 6, the specific process of the densification treatment is: placing the ceramicized brake ventilation disc in a heating furnace and heating it to 1600° C. to 1800° C., keeping it warm for 2 h to 3 h, and then cooling it to room temperature with the furnace.

10. The method for forming a brake ventilated disc according to claim 6, characterized in that: In step 5, the specific steps of the ceramic treatment are as follows: Step 5.1, uniformly mixing silicon powder, silicon carbide powder and iron powder in a mass ratio of (3.5-5.5):(4.5-3.5):(0.1-0.3) to obtain a ceramic raw material; Step 5.2, placing the carbonized composite fiber body (11) obtained in step 4 into a crucible, and completely wrapping the composite fiber body (11) with the ceramic raw material obtained in step 5.1; Step 5.3, place the composite fiber body (11) connected to the crucible after treatment in step 5.2 in a heating furnace, first heat it to 1500℃~1600℃, keep it warm for 1h~2h, then continue to heat it to 1600℃~1700℃, keep it warm for 1h~2h, then continue to heat it to 1700℃~1800℃, keep it warm for 1h~2h, and then cool it to room temperature with the furnace.

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