Carbon fiber preform, preparation method thereof, brake disc and vehicle

Abstract

The invention provides a carbon fiber preform, a preparation method thereof, a brake disc and a vehicle. The tensile strength of the carbon fiber preform can be enhanced. The carbon fiber prefabricated body comprises a first side and a second side, the first side and the second side are oppositely arranged in the thickness direction of the carbon fiber prefabricated body, the carbon fiber prefabricated body comprises a plurality of carbon fiber layers arranged in a stacked mode, a plurality of interlayer fibers are arranged between every two adjacent carbon fiber layers and extend in the thickness direction of the carbon fiber layers, and the first side and the second side are oppositely arranged. In the direction from the first side to the second side, the density of the interlayer fibers is firstly increased and then reduced.

Description

Technical Field

[0001] The present application relates to the technical field of brake systems, and in particular to a carbon fiber preform and a preparation method thereof, a brake disc and a vehicle. Background Art

[0002] Brake discs are key components of vehicle braking systems and can slow down or stop vehicles. Brake discs generally use carbon fiber preforms as the main skeleton structure. Carbon fiber preforms are usually made by needle-punching carbon fiber cloth layers and carbon fiber mesh layers. However, the carbon fiber preform has uneven needle-punching in the thickness direction, resulting in low tensile strength of the carbon fiber preform, which reduces the friction performance of the brake disc and affects the braking performance of the vehicle. Summary of the invention

[0003] The embodiments of the present application provide a carbon fiber preform and a preparation method thereof, a brake disc and a vehicle, which can enhance the tensile strength of the carbon fiber preform, improve the friction performance of the brake disc, and thus enhance the braking performance of the vehicle.

[0004] In a first aspect, the present application provides a carbon fiber preform for a brake disc. The carbon fiber preform comprises a first side and a second side, wherein the first side is arranged opposite to the second side along the thickness direction of the carbon fiber preform, the carbon fiber preform comprises a plurality of stacked carbon fiber layers, a plurality of interlayer fibers are arranged between two adjacent carbon fiber layers, the plurality of interlayer fibers extend along the thickness direction of the carbon fiber layer, and the density of the interlayer fibers increases first and then decreases in the direction from the first side to the second side.

[0005] Among them, the multiple carbon fiber layers include a first carbon fiber layer, multiple second carbon fiber layers and multiple third carbon fiber layers, the multiple second fiber layers are located on one side of the first carbon fiber layer, and the multiple third carbon fiber layers are located on the other side of the first carbon fiber layer; the multiple interlayer fibers include multiple first interlayer fibers and multiple second interlayer fibers, and the extension direction of the multiple first interlayer fibers is opposite to the extension direction of the multiple second interlayer fibers; the multiple first interlayer fibers are located in the first carbon fiber layer and the multiple second carbon fiber layers, and the density of the multiple first interlayer fibers gradually decreases along the direction from the first carbon fiber layer to the second carbon fiber layer; the multiple second interlayer fibers are located in the first carbon fiber layer and the multiple third carbon fiber layers, and the density of the multiple second interlayer fibers gradually decreases along the direction from the first carbon fiber layer to the third carbon fiber layer.

[0006] Wherein, in the first carbon fiber layer, a distance D1 between two adjacent first interlayer fibers is between 0.5 mm and 2 mm.

[0007] Wherein, in the first carbon fiber layer, a distance D2 between two adjacent second interlayer fibers is between 0.5 mm and 2 mm.

[0008] In each of the second carbon fiber layers, a distance D3 between two adjacent first interlayer fibers is between 2 mm and 10 mm.

[0009] Wherein, in each of the third carbon fiber layers, in each of the third carbon fiber layers, a distance D4 between two adjacent second interlayer fibers is between 2 mm and 10 mm.

[0010] The carbon fiber preform further includes a middle part, a first part and a second part, wherein the first part and the second part are respectively located on opposite sides of the middle part along the thickness direction of the carbon fiber preform; the middle part includes the first carbon fiber layer, a part of a plurality of first interlayer fibers located in the first carbon fiber layer, and a part of a plurality of second interlayer fibers located in the first carbon fiber layer, the first part includes at least one second carbon fiber layer and a part of a plurality of first interlayer fibers located in the second carbon fiber layer, the second part includes at least one third carbon fiber layer and a part of a plurality of second interlayer fibers located in the third carbon fiber layer, wherein the shear strength of the middle part is greater than the shear strength of the first part and the second part.

[0011] The shear strength of the middle portion is between 10 MPa and 30 MPa, and the shear strengths of the first portion and the second portion are each independently between 5 MPa and 20 MPa.

[0012] Among them, the interlayer fibers are in a "Y" shape, and the interlayer fibers include a first section and a second section, the first section is in an "I" shape, the second section is in a "V" shape, the second section is connected to one side of the first section, and in the interlayer fibers, the direction from the first section to the second section is the extension direction of the interlayer fibers; in the carbon fiber layer, the first sections of two adjacent interlayer fibers are spaced apart.

[0013] Wherein, the width W of the interlayer fibers is between 0.2 mm and 5 mm.

[0014] Wherein, the depth L of the interlayer fibers is between 1 mm and 15 mm.

[0015] Wherein, at least one of the carbon fiber layers is a carbon fiber cloth layer, and at least one of the carbon fiber layers is a carbon fiber web layer.

[0016] In a second aspect, the present application further provides a brake disc, comprising silicon carbide and a carbon fiber preform as described in any one of the above items, wherein the carbon fiber preform contains the silicon carbide.

[0017] In a third aspect, the present application further provides a vehicle, comprising a wheel, a brake pad and a brake disc as described above, wherein the brake disc is mounted on the wheel, and the brake pad is mounted on the brake disc.

[0018] In a fourth aspect, the present application also provides a method for preparing a carbon fiber preform, comprising: step one, providing a first carbon fiber layer, a plurality of second carbon fiber layers and a plurality of third carbon fiber layers; step two, stacking a layer of the second carbon fiber layer on one side of the first carbon fiber layer, and stacking a layer of the third carbon fiber layer on the other side of the first carbon fiber layer; step three, needle-punching the second carbon fiber layer and the first carbon fiber layer along the direction of the second carbon fiber layer toward the first carbon fiber layer to form a plurality of first interlayer fibers between the second carbon fiber layer and the first carbon fiber layer, and needle-punching the third carbon fiber layer and the first carbon fiber layer along the direction of the third carbon fiber layer toward the first carbon fiber layer to form a plurality of second interlayer fibers between the third carbon fiber layer and the first carbon fiber layer; step Step 4, stacking at least one layer of the second carbon fiber layer on the surface of the second carbon fiber layer facing away from the first carbon fiber layer, and stacking at least one layer of the third carbon fiber layer on the surface of the third carbon fiber layer facing away from the first carbon fiber layer; Step 5, needle-punching at least two layers of the second carbon fiber layers and the first carbon fiber layer along the direction of the second carbon fiber layer toward the first carbon fiber layer to form a plurality of first interlayer fibers between the at least two layers of the second carbon fiber layers and the first carbon fiber layer, and needle-punching at least two layers of the third carbon fiber layers and the first carbon fiber layer along the direction of the third carbon fiber layer toward the first carbon fiber layer to form a plurality of second interlayer fibers between the at least two layers of the third carbon fiber layers and the first carbon fiber layer; repeat steps 4 and 5 until the carbon fiber preform is obtained.

[0019] Wherein, the needle punching density of the first carbon fiber layer is 50 needles / cm 2 Up to 500 stitches / cm 2 The needle punching density of each of the second carbon fiber layers and the needle punching density of each of the third carbon fiber layers are both 5 needles / cm 2 Up to 500 stitches / cm 2 between.

[0020] Among them, the ratio of the needling density of the first carbon fiber layer to the needling density of the second carbon fiber layer farthest from the first carbon fiber layer among the multiple second carbon fiber layers, and the ratio of the needling density of the first carbon fiber layer to the needling density of the third carbon fiber layer farthest from the first carbon fiber layer among the multiple third carbon fiber layers are both between 8 and 10.

[0021] In the carbon fiber preform provided in the embodiment of the present application, along the thickness direction of the carbon fiber preform, multiple first interlayer fibers and multiple second interlayer fibers are symmetrically arranged about the first carbon fiber layer, and the density of the multiple first interlayer fibers and the multiple second interlayer fibers both show a gradient change, which can not only make the carbon fiber preform present the characteristics of high strength in the middle and gradually decreasing strength on both sides in the thickness direction, but also improve the symmetry of the strength of the carbon fiber preform in the thickness direction, and can increase the service life of the brake disc. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be described below.

[0023] Figure 1 is a structural schematic diagram of a vehicle provided in an embodiment of the present application;

[0024] Figure 2 yes Figure 1 A schematic diagram of the structure of a carbon fiber preform of a brake disc in the vehicle shown;

[0025] Figure 3 yes Figure 2 A schematic diagram of the partial structure of the carbon fiber preform shown;

[0026] Figure 4 yes Figure 1 Schematic diagram of the preparation process of the carbon fiber preform shown;

[0027] Figure 5 It is a schematic structural diagram of the bidirectional needling machine provided in this application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0029] Please refer to Figure 1 , Figure 1 It is a schematic diagram of the structure of a vehicle 100 provided in an embodiment of the present application.

[0030] The vehicle 100 provided in the embodiment of the present application may be, but is not limited to, a sedan, a truck, a pickup truck, a commercial vehicle, a bus, an off-road vehicle, and a new energy vehicle, etc., and the present application does not impose any restrictions on this. The vehicle 100 may include a body 110, a brake disc 120, a brake pad (not shown) and a wheel 130, the wheel 130 being mounted on the body 110, the brake disc 120 being mounted on the wheel 130, and being able to rotate under the drive of the wheel 130. The brake pad is mounted on the brake disc. The brake disc 120 rubs against the brake pad to achieve the purpose of decelerating and braking the vehicle 100.

[0031] The brake disc 120 includes a carbon fiber preform 10 and silicon carbide, and the silicon carbide is combined with the carbon fiber preform 10. That is, the carbon fiber preform 10 contains silicon carbide. It can be understood that silicon carbide can increase the hardness of the carbon fiber preform 10, thereby enhancing the friction performance and mechanical properties of the brake disc 120.

[0032] Please refer to Figure 2 and Figure 3 , Figure 2 yes Figure 1 The schematic diagram of the structure of the carbon fiber preform 10 of the brake disc 120 in the vehicle 100 is shown. Figure 3 yes Figure 2 A partial structural schematic diagram of a carbon fiber preform 10 is shown.

[0033] In this embodiment, the carbon fiber preform 10 is prepared by a bidirectional needle punching process. The thickness of the carbon fiber preform 10 is between 15 mm and 110 mm. The carbon fiber preform 10 includes a first side 101 and a second side 102, and along the thickness direction of the carbon fiber preform 10, the first side 101 and the second side 102 are arranged opposite to each other. The carbon fiber preform 10 also includes a plurality of stacked carbon fiber layers 10a, and a plurality of interlayer fibers 13 are arranged between two adjacent carbon fiber layers 10a. The plurality of interlayer fibers 13 extend along the thickness direction of the carbon fiber layer 10a. In the direction from the first side 101 to the second side 102, the density of the interlayer fibers 13 in the carbon fiber preform 10 first increases and decreases and then decreases.

[0034] It is understandable that by arranging a plurality of interlayer fibers 13 between two adjacent carbon fiber layers 10a, the tensile strength and structural strength of the carbon fiber preform 10 can be increased, thereby improving the friction performance and mechanical properties of the brake disc 120, and further improving the braking performance of the vehicle 100.

[0035] In this embodiment, the number of carbon fiber layers 10a is between 30 and 55 layers. Among them, at least one carbon fiber layer 10a is a carbon fiber cloth layer, and at least one carbon fiber layer 10a is a carbon fiber mesh layer. The thickness H1 of the carbon fiber cloth layer is between 0.2mm-1mm, and the thickness H2 of the carbon fiber mesh layer is between 0.1mm-0.6mm. Exemplarily, the multiple carbon fiber layers 10a include multiple carbon fiber cloth layers and multiple carbon fiber mesh layers, and the multiple carbon fiber cloth layers and the multiple carbon fiber mesh layers are alternately stacked. At this time, the sum of the thickness H1 of a carbon fiber cloth layer and the thickness H2 of two carbon fiber mesh layers is between 0.3mm and 1.6mm.

[0036] In addition, the plurality of carbon fiber layers 10a include a first carbon fiber layer 11, a plurality of second carbon fiber layers 12, and a plurality of third carbon fiber layers 18. The plurality of second carbon fiber layers 12 are located on one side of the first carbon fiber layer 11, and the plurality of third carbon fiber layers 18 are located on the other side of the first carbon fiber layer 11. The first carbon fiber layer 11 may be a carbon fiber cloth layer or a carbon fiber mesh layer; the plurality of second carbon fiber layers 12 may all be carbon fiber cloth layers or carbon fiber mesh layers, or some of the second carbon fiber layers 12 may be carbon fiber cloth layers, and some of the second carbon fiber layers 12 may be carbon fiber mesh layers; the plurality of third carbon fiber layers 18 may all be carbon fiber cloth layers or carbon fiber mesh layers, or some of the third carbon fiber layers 18 may be carbon fiber cloth layers, and some of the third carbon fiber layers 18 may be carbon fiber mesh layers.

[0037] In this embodiment, each interlayer fiber 13 is roughly Y-shaped. Each interlayer fiber 13 includes a first section 131 and a second section 132, and the second section 132 is connected to one side of the first section 131. The first section 131 is "I"-shaped, and the second section 132 is "V"-shaped. In each interlayer fiber 13, the direction from the first section 131 to the second section 123 is the extension direction of the interlayer fiber 13. The distance D0 between the first sections 131 of two adjacent interlayer fibers 13 is between 0.5 mm and 10 mm.

[0038] In addition, the width W of each interlayer fiber 13 is between 0.2 mm and 5 mm, and the depth L of each interlayer fiber 13 is between 1 mm and 15 mm. Exemplarily, the width W of each interlayer fiber 13 is between 0.5 mm and 1.5 mm, and the depth L of each interlayer fiber 13 is between 3 mm and 10 mm. It should be noted that the width W of the interlayer fiber 13 is the dimension of the interlayer fiber 13 along the length direction parallel to the carbon fiber preform 10, and the depth L of the interlayer fiber 13 is the dimension of the interlayer fiber 13 in the thickness direction of the carbon fiber preform 10.

[0039] In addition, the plurality of interlayer fibers 13 include a plurality of first interlayer fibers 13a and a plurality of second interlayer fibers 13b. The extension direction of the plurality of first interlayer fibers 13a is opposite to the extension direction of the plurality of second interlayer fibers 13b. Exemplarily, the plurality of first interlayer fibers 13a are all in a "Y" shape, and the plurality of second interlayer fibers 13b are all in an inverted "Y" shape.

[0040] It should be understood that in the production process of preparing the brake disc 120 using the carbon fiber preform 10, the carbon fiber preform 10 is usually subjected to chemical vapor infiltration (CVI) treatment and siliconization treatment. It is understandable that by providing the "Y"-shaped first interlayer fiber 13a and the inverted "Y"-shaped second interlayer fiber 13b, during the treatment process, the gas can enter the interior of the carbon fiber preform 10 from the first side 101 and the second side 102 of the carbon fiber preform 10 at the same time, which helps to increase the density and carbon content of the middle layer of the carbon fiber preform 10, thereby facilitating silicon atoms to enter the interior of the carbon fiber preform 10 in the subsequent siliconization process, generating more silicon carbide, and further enhancing the hardness of the carbon fiber preform 10.

[0041] In this embodiment, the plurality of first interlayer fibers 13a are located in the first carbon fiber layer 11 and the plurality of second carbon fiber layers 12. The density of the plurality of first interlayer fibers 13a gradually decreases from the first carbon fiber layer 11 to the second carbon fiber layer 12. In the first carbon fiber layer 11, the distance D1 between two adjacent first interlayer fibers 13a is between 0.5 mm and 2 mm. In each second carbon fiber layer 12, the distance D3 between two adjacent first interlayer fibers 13a is between 2 mm and 10 mm.

[0042] The plurality of second interlayer fibers 13b are all located in the first carbon fiber layer 11 and the plurality of third carbon fiber layers 18. The density of the plurality of second interlayer fibers 13b gradually decreases along the direction from the first carbon fiber layer 11 to the third carbon fiber layer 18. In the first carbon fiber layer 11, the distance D2 between two adjacent second interlayer fibers 13b is between 0.5 mm and 2 mm. Exemplarily, the distance D2 between two adjacent second interlayer fibers 13b is equal to the distance D1 between two adjacent first interlayer fibers 13a. In each third carbon fiber layer 18, the distance D4 between two adjacent second interlayer fibers 13b is between 2 mm and 10 mm. Exemplarily, the distance D4 between two adjacent second interlayer fibers 13b is equal to the distance D3 between two adjacent first interlayer fibers 13a.

[0043] In the present embodiment, along the thickness direction of the carbon fiber preform 10, a plurality of first interlayer fibers 13a and a plurality of second interlayer fibers 13b are symmetrically arranged about the first carbon fiber layer 11, and the densities of the plurality of first interlayer fibers 13a and the plurality of second interlayer fibers 13b both show a gradient change, which can not only make the carbon fiber preform 10 present the characteristics of high strength in the middle and gradually decreasing strength on both sides in the thickness direction, but also improve the symmetry of the strength of the carbon fiber preform 10 in the thickness direction, and can increase the service life of the brake disc 120.

[0044] Please continue reading Figure 2 The carbon fiber preform 10 further includes a middle portion 15, a first portion 16 and a second portion 17. The first portion 16 and the second portion 17 are respectively arranged on opposite sides of the middle portion 10a along the thickness direction of the carbon fiber preform 10. The middle portion 15 includes a first carbon fiber layer 11, a portion of a plurality of first interlayer fibers 13a located in the first carbon fiber layer, and a portion of a plurality of second interlayer fibers 13b located in the first carbon fiber layer. The first portion 16 includes at least one second carbon fiber layer 12 and a portion of a plurality of first interlayer fibers 13a located in the second carbon fiber layer. The second portion 17 includes at least one third carbon fiber layer 18 and a portion of a plurality of second interlayer fibers 13b located in the third carbon fiber layer. The shear strength of the middle portion 15 is greater than the shear strength of the first portion 16 and the second portion 17. Exemplarily, the shear strength of the middle portion 15 is between 10 MPa and 30 MPa, and the shear strength of the first portion 16 and the shear strength of the second portion 17 are each independently between 5 MPa and 20 MPa. Exemplarily, the shear strength of the first portion 16 is equal to the shear strength of the second portion 17 .

[0045] It is understandable that during the friction process, the stress borne by the middle portion 15 of the brake disc 120 is generally greater than the stress borne by the first portion 16 and the second portion 17, and the shear strength of the middle portion 15 is higher than the shear strength of the first portion 16 and the second portion 17, which is beneficial to increasing the service life of the brake disc 120, thereby improving the reliability of the vehicle 100.

[0046] The embodiments of the present application also provide a method for preparing a carbon fiber preform.

[0047] See also Figure 4 , Figure 4 yes Figure 1 The schematic diagram of the preparation process of the carbon fiber preform 10 is shown.

[0048] In this embodiment, the carbon fiber preform 10 is prepared by a bidirectional needle punching process. The preparation method of the carbon fiber preform 10 includes the following steps S1 to S5.

[0049] Step 1 S1, providing a first carbon fiber layer, a plurality of second carbon fiber layers and a plurality of third carbon fiber layers.

[0050] Step 2 S2, stacking a second carbon fiber layer on one side of the first carbon fiber layer, and stacking a third carbon fiber layer on the other side of the first carbon fiber layer.

[0051] Step three S3, needle-punching the first carbon fiber layer and the second carbon fiber layer along the direction of the second carbon fiber layer toward the first carbon fiber layer to form a plurality of first interlayer fibers between the first carbon fiber layer and the second carbon fiber layer, and needle-punching the third carbon fiber layer and the first carbon fiber layer along the direction of the third carbon fiber layer toward the first carbon fiber layer to form a plurality of second interlayer fibers between the third carbon fiber layer and the first carbon fiber layer.

[0052] The needle punching density of a first carbon fiber layer, a second carbon fiber layer and a third carbon fiber layer is 50 needles / cm 2 Up to 500 stitches / cm 2 Exemplarily, the second carbon fiber layer and the third carbon fiber layer are symmetrical with respect to the first carbon fiber layer, and have the same needle punching density.

[0053] Step 4 S4, laminating at least one second carbon fiber layer on a surface of the second carbon fiber layer facing away from the first carbon fiber layer, and laminating at least one third carbon fiber layer on a surface of the third carbon fiber layer facing away from the first carbon fiber layer.

[0054] Step five S5, needle-punching at least two second carbon fiber layers and the first carbon fiber layer along the direction from the second carbon fiber layer to the first carbon fiber layer to form a plurality of first interlayer fibers between the at least two second carbon fiber layers and the first carbon fiber layer, and needle-punching at least two third carbon fiber layers and the first carbon fiber layer along the direction from the third carbon fiber layer to the first carbon fiber layer to form a plurality of second interlayer fibers between the at least two third carbon fiber layers and the first carbon fiber layer.

[0055] The needle punching density of each second carbon fiber layer and each third carbon fiber layer is 5 needles / cm 2 Up to 500 stitches / cm 2 Exemplarily, each of the second carbon fiber layer and the third carbon fiber layer is symmetrical with respect to the first carbon fiber layer, and has the same needle punching density.

[0056] Repeat steps 4 and 5 until a carbon fiber preform is obtained.

[0057] In this embodiment, the needle punching density of the first carbon fiber layer is 50 needles / cm 2 Up to 500 stitches / cm 2 The needle punching density of the second carbon fiber layers and the needle punching density of the third carbon fiber layers are both 5 needles / cm2 Up to 500 stitches / cm 2 Exemplarily, the needling density of the plurality of second carbon fiber layers is equal to the needling density of the plurality of third carbon fiber layers. In addition, the ratio of the needling density of the first carbon fiber layer to the needling density of the second carbon fiber layer farthest from the first carbon fiber layer among the plurality of second carbon fiber layers, and the ratio of the needling density of the first carbon fiber layer to the needling density of the third carbon fiber layer farthest from the first carbon fiber layer among the plurality of third carbon fiber layers are both between 8 and 10.

[0058] Among them, the ratio of the needling density of the first carbon fiber layer to the needling density of the second carbon fiber layer in contact with the first carbon fiber layer among the multiple second carbon fiber layers is between 100:95 and 100:80; in two adjacent second carbon fiber layers, the ratio of the needling density away from the first carbon fiber layer to the needling density close to the first carbon fiber layer is between 100:95 and 100:80; the ratio of the needling density of the first carbon fiber layer to the needling density of the third carbon fiber layer in contact with the first carbon fiber layer among the multiple third carbon fiber layers is between 100:95 and 100:80; in two adjacent third carbon fiber layers, the ratio of the needling density away from the first carbon fiber layer to the needling density close to the first carbon fiber layer is between 100:95 and 100:80.

[0059] In this embodiment, the carbon fiber preform 10 can be made into a brake disc through chemical vapor deposition treatment, high temperature treatment and siliconization treatment and other process processes. Among them, the reaction temperature of chemical vapor deposition is between 980°C and 1200°C. The total deposition time is between 200h and 1000h. The gas flow rate of the reaction gas is between 10L / min and 200L / min. Exemplarily, methane, natural gas, propane, propylene and other gases can be used as reaction gases for chemical vapor deposition. In addition, during the chemical vapor deposition process, inert gases such as nitrogen or argon are usually introduced to avoid product oxidation. Among them, the gas flow rate of nitrogen or argon is between 1L / min and 20L / min. In this embodiment, by performing chemical vapor deposition treatment on the carbon fiber preform, pyrolytic carbon can be generated on the surface of the carbon fiber preform 10 to make the structure of the carbon fiber preform denser.

[0060] In this embodiment, the reaction temperature during the high temperature treatment is between 1900°C and 2800°C. The heating rate is between 0.5°C / min and 5°C / min. The total reaction time is 120h. The insulation time is between 1h-20h. Through the high temperature treatment process, the carbon fiber preform can be turned into a porous structure for subsequent processing. At the same time, under the action of high temperature, part of the pyrolytic carbon on the surface of the carbon fiber preform will be transformed into graphite with an ordered structure, which is beneficial to improve the friction performance and chemical stability of the carbon fiber preform.

[0061] During the siliconizing process, silicon powder is vaporized into silicon atoms under high temperature, and silicon atoms react with carbon atoms to form silicon carbide, which is combined with the carbon fiber preform. The reaction temperature is between 1400°C and 1800°C, and the reaction time is between 1h and 20h.

[0062] It can be understood that both sides of the carbon fiber preform in the thickness direction form a porous structure during the high-temperature treatment process, which is conducive to more silicon atoms entering the interior of the carbon fiber preform and generating silicon carbide, thereby generating silicon carbide on the surface and inside of the carbon fiber preform, which can greatly improve the density of the carbon fiber preform, and thus greatly improve the friction performance of the brake disc.

[0063] See also Figure 5 , Figure 5 It is a schematic structural diagram of the bidirectional needling machine 200 provided in the present application.

[0064] The carbon fiber preform 10 provided in the present application can be obtained by Figure 5 The bidirectional needling machine 200 shown is made. The bidirectional needling machine 200 includes a controller 210, two electrodes 220, two lifting platforms 230, two needle plates 240, two stripping plates 250 and a carrying platform 260. Among them, the carrying platform 260 is used to carry the needle-punched sample for preparing the carbon fiber preform 10. Along the height direction of the bidirectional needling machine 200, the two stripping plates 250 are respectively arranged on the opposite sides of the carrying platform 260. Each stripping plate 250 is provided with a plurality of needle holes 251, and the plurality of needle holes 251 are arranged at intervals from each other. The needle holes 251 are used to allow the needles to pass through the stripping plates 250 to needle-punch the plurality of carbon fiber layers, thereby introducing interlayer fibers 13 into the plurality of carbon fiber layers.

[0065] Each needle plate 240 is located on a side of a stripping plate 250 away from the carrying platform 260, and is spaced apart from and opposite to the stripping plate 250. Each needle plate 240 includes a plurality of needles 241, and the plurality of needles 241 are spaced apart from each other. Each needle 241 is arranged corresponding to a needle hole 251 of the stripping plate 250. When the needle plate 240 is needled, the plurality of needles 241 respectively pass through the plurality of needle holes 251 to achieve needled carbon fiber layer. Each needle 241 has a reverse hook barb, so as to hook the fibers of the carbon fiber layer to form interlayer fibers when needled the carbon fiber layer.

[0066] Each lifting platform 230 is located on a side of a needle plate 240 away from a stripping plate 250, and is fixedly connected to the needle plate 240. The lifting platform 230 is used to control the needle plate 240 to rise or fall, so as to achieve the needle plate 240 needle punching of the carbon fiber layer. Each electrode 220 is located on a side of a lifting platform 230 away from a needle plate 240, and is electrically connected to a lifting platform 230 and a controller 210. The controller 210 is used to control the electrode 220 to transmit an electrical signal to the lifting platform 230, so as to control the lifting platform 230 to rise or fall, thereby driving the needle plate 240 to rise or fall.

[0067] During the preparation of the carbon fiber preform 10, the controller 210 is started to transmit an electrical signal to the electrode 220 to control the movement of the lifting platform 230. The needle plate 240 is driven by the lifting platform 230 to reciprocate up and down, so that the needles 241 on the needle plate can repeatedly needle the needle-punched sample to form interlayer fibers 13 in the needle-punched sample to increase the structural strength of the carbon fiber preform 10.

[0068] It is understandable that the two needle plates 240 in the bidirectional needling machine 200 are both provided with a plurality of needles 241, and during the preparation process of the carbon fiber preform 10, the carbon fiber layer can be needled from both the upper and lower sides of the carbon fiber layer, so that the needled effect of the prepared carbon fiber preform 10 is more uniform and symmetrical on both sides, thereby improving the structural strength of the carbon fiber preform 10. At the same time, during the preparation process, there is no need to manually flip the needled sample, which helps to shorten the production time of the carbon fiber preform 10 and improve production efficiency.

[0069] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A carbon fiber preform for a brake disc, characterized in that: The carbon fiber preform includes a first side and a second side. Along the thickness direction of the carbon fiber preform, the first side is arranged opposite to the second side. The carbon fiber preform includes a plurality of stacked carbon fiber layers. A plurality of interlayer fibers are arranged between two adjacent carbon fiber layers. The plurality of interlayer fibers extend along the thickness direction of the carbon fiber layer. In the direction from the first side to the second side, the density of the interlayer fibers first increases and then decreases.

2. The carbon fiber preform according to claim 1, characterized in that: The plurality of carbon fiber layers include a first carbon fiber layer, a plurality of second carbon fiber layers and a plurality of third carbon fiber layers, the plurality of second carbon fiber layers are located on one side of the first carbon fiber layer, and the plurality of third carbon fiber layers are located on the other side of the first carbon fiber layer; The plurality of interlayer fibers include a plurality of first interlayer fibers and a plurality of second interlayer fibers, and the extension direction of the plurality of first interlayer fibers is opposite to the extension direction of the plurality of second interlayer fibers; The plurality of first interlayer fibers are located in the first carbon fiber layer and the plurality of second carbon fiber layers, and the density of the plurality of first interlayer fibers gradually decreases in a direction from the first carbon fiber layer to the second carbon fiber layer; The plurality of second interlayer fibers are located in the first carbon fiber layer and the plurality of third carbon fiber layers, and the density of the plurality of second interlayer fibers gradually decreases in a direction from the first carbon fiber layer to the third carbon fiber layer.

3. The carbon fiber preform according to claim 2, characterized in that: In the first carbon fiber layer, a distance D1 between two adjacent first interlayer fibers is between 0.5 mm and 2 mm.

4. The carbon fiber preform according to claim 2 or 3, characterized in that: In the first carbon fiber layer, a distance D2 between two adjacent second interlayer fibers is between 0.5 mm and 2 mm.

5. The carbon fiber preform according to claim 2, characterized in that: In each of the second carbon fiber layers, a distance D3 between two adjacent first interlayer fibers is between 2 mm and 10 mm.

6. The carbon fiber preform according to claim 2 or 5, characterized in that: In each of the third carbon fiber layers, a distance D4 between two adjacent second interlayer fibers is between 2 mm and 10 mm.

7. The carbon fiber preform according to claim 2, characterized in that: The carbon fiber preform further comprises a middle portion, a first portion and a second portion, wherein along the thickness direction of the carbon fiber preform, the first portion and the second portion are respectively located at opposite sides of the middle portion; The middle part includes the first carbon fiber layer, a part of the plurality of first interlayer fibers located in the first carbon fiber layer, and a part of the plurality of second interlayer fibers located in the first carbon fiber layer, the first part includes at least one second carbon fiber layer and a part of the plurality of first interlayer fibers located in the second carbon fiber layer, and the second part includes at least one third carbon fiber layer and a part of the plurality of second interlayer fibers located in the third carbon fiber layer, wherein the shear strength of the middle part is greater than the shear strength of the first part and the second part.

8. The carbon fiber preform according to claim 7, characterized in that: The shear strength of the middle portion is between 10 MPa and 30 MPa, and the shear strengths of the first portion and the second portion are each independently between 5 MPa and 20 MPa.

9. The carbon fiber preform according to claim 1, characterized in that: The interlayer fiber is in a "Y" shape, and includes a first section and a second section, the first section is in an "I" shape, the second section is in a "V" shape, the second section is connected to one side of the first section, and in the interlayer fiber, the direction from the first section to the second section is the extension direction of the interlayer fiber; In the carbon fiber layer, the first sections of two adjacent interlayer fibers are arranged at intervals.

10. The carbon fiber preform according to claim 1, characterized in that: The width W of the interlayer fibers is between 0.2 mm and 5 mm.

11. The carbon fiber preform according to claim 1, characterized in that: The depth L of the interlayer fibers is between 1 mm and 15 mm.

12. The carbon fiber preform according to claim 1, characterized in that: At least one of the carbon fiber layers is a carbon fiber cloth layer, and at least one of the carbon fiber layers is a carbon fiber web layer.

13. A brake disc, characterized in that: The invention comprises silicon carbide and a carbon fiber preform as claimed in any one of claims 1 to 12, wherein the carbon fiber preform contains the silicon carbide.

14. A vehicle, characterized in that: It comprises a wheel, a brake pad and a brake disc as claimed in claim 13, wherein the brake disc is mounted on the wheel and the brake pad is mounted on the brake disc.

15. A method for preparing a carbon fiber preform, characterized in that: include: Step 1, providing a first carbon fiber layer, a plurality of second carbon fiber layers and a plurality of third carbon fiber layers; Step 2: stacking a layer of the second carbon fiber layer on one side of the first carbon fiber layer, and stacking a layer of the third carbon fiber layer on the other side of the first carbon fiber layer; Step 3, needle-punching the second carbon fiber layer and the first carbon fiber layer along the direction from the second carbon fiber layer to the first carbon fiber layer to form a plurality of first interlayer fibers between the second carbon fiber layer and the first carbon fiber layer, and needle-punching the third carbon fiber layer and the first carbon fiber layer along the direction from the third carbon fiber layer to the first carbon fiber layer to form a plurality of second interlayer fibers between the third carbon fiber layer and the first carbon fiber layer; Step 4: stacking at least one layer of the second carbon fiber layer on a surface of the second carbon fiber layer facing away from the first carbon fiber layer, and stacking at least one layer of the third carbon fiber layer on a surface of the third carbon fiber layer facing away from the first carbon fiber layer; Step 5, needle-punching at least two layers of the second carbon fiber layer and the first carbon fiber layer along the direction from the second carbon fiber layer to the first carbon fiber layer to form a plurality of first interlayer fibers between the at least two layers of the second carbon fiber layer and the first carbon fiber layer, and needle-punching at least two layers of the third carbon fiber layer and the first carbon fiber layer along the direction from the third carbon fiber layer to the first carbon fiber layer to form a plurality of second interlayer fibers between the at least two layers of the third carbon fiber layer and the first carbon fiber layer; Repeat steps 4 and 5 until the carbon fiber preform is obtained.

16. The method for preparing a carbon fiber preform according to claim 15, characterized in that: The needle punching density of the first carbon fiber layer is 50 needles / cm 2 Up to 500 stitches / cm 2 The needle punching density of each of the second carbon fiber layers and the needle punching density of each of the third carbon fiber layers are both 5 needles / cm 2 Up to 500 stitches / cm 2 between.

17. The method for preparing a carbon fiber preform according to claim 15, characterized in that: The ratio of the needling density of the first carbon fiber layer to the needling density of the second carbon fiber layer farthest from the first carbon fiber layer among the plurality of second carbon fiber layers, and the ratio of the needling density of the first carbon fiber layer to the needling density of the third carbon fiber layer farthest from the first carbon fiber layer among the plurality of third carbon fiber layers are both between 8 and 10.

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