Brake disc and manufacturing method therefor, and vehicle

Abstract

A brake disc and a manufacturing method therefor, and a vehicle. The brake disc comprises a base body and a friction layer. The friction layer comprises a first surface and a second surface that are opposite each other. The first surface is connected to the base body, and the second surface has a less crack density than the first surface.

Description

Brake disc, manufacturing method thereof and vehicle

[0001] The present application claims priority to the Chinese patent application No. 202410844929.6, filed on June 27, 2024, and entitled "Brake disc, manufacturing method thereof and vehicle", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of brake discs, in particular to a brake disc, a manufacturing method thereof and a vehicle. BACKGROUND

[0003] At present, due to the requirements of high friction coefficient and long service life, a carbonized silicon friction layer is usually loaded on the base body of the brake disc. However, during the sintering process of the carbon ceramic brake disc, due to the mismatch of the thermal expansion coefficients between the carbonized silicon and the base body, a large number of cracks will be generated in the friction layer. If the cracks are too dense, the friction layer will be peeled off, and if the cracks are too sparse, a large amount of carbonized silicon will be used, resulting in an increase in the manufacturing cost of the brake disc. Therefore, how to solve the problem of too dense cracks on the surface of the friction layer and reduce the peeling of the friction layer has become a key issue. SUMMARY

[0004] The purpose of the present application is to provide a brake disc, a manufacturing method thereof and a vehicle, which solve the problem of peeling of the friction layer on the surface of the brake disc.

[0005] To achieve the purpose of the present application, the present application provides the following technical solutions:

[0006] In a first aspect, the present application provides a brake disc, comprising a base body and a friction layer, the friction layer comprising a first face and a second face opposite to each other, the first face being connected to the base body, and the crack density of the second face being less than that of the first face.

[0007] In an embodiment, the friction layer comprises a first friction layer and a second friction layer, the first friction layer being arranged on the base body, the second friction layer being arranged on a face of the first friction layer opposite to the base body, the first face being a face of the first friction layer opposite to the second friction layer, the second face being a face of the second friction layer opposite to the first friction layer, and the crack density of the second friction layer being less than that of the first friction layer.

[0008] In an embodiment, the first friction layer comprises first carbonized silicon particles, and the second friction layer comprises second carbonized silicon particles, the particle size of the second carbonized silicon particles being greater than that of the first carbonized silicon particles.

[0009] In an embodiment, the first silicon carbide particles have a particle size of 0.3 μm to 50 μm, and the second silicon carbide particles have a particle size of 50 μm to 200 μm.

[0010] In an embodiment, the first friction layer comprises first silicon carbide particles, and the second friction layer comprises second silicon carbide particles, and the mass ratio of the second silicon carbide particles in the second friction layer is greater than the mass ratio of the first silicon carbide particles in the first friction layer.

[0011] In an embodiment, the mass ratio of the first silicon carbide particles in the first friction layer is 50% to 80%, and the mass ratio of the second silicon carbide particles in the second friction layer is 70% to 95%.

[0012] In an embodiment, the average crack spacing λ f1 is 2 mm to 9 mm.

[0013] In an embodiment, the λ f1 satisfies the relationship: TSiC V is the content of the first silicon carbide particles in the first friction layer, and α is the crack spacing base of the first friction layer, and the α has a value range of 0.3 mm to 0.7 mm.

[0014] In an embodiment, the average crack spacing λ f2 is 3 mm to 14 mm.

[0015] In an embodiment, the λ f2 satisfies the relationship: SSiC V is the content of the second silicon carbide particles in the second friction layer, and δ is the crack spacing base of the second friction layer, and the δ has a value range of 0.36 mm to 1 mm.

[0016] In an embodiment, the crack width in the first friction layer is 2 μm to 30 μm, and the crack width in the second friction layer is 10 μm to 80 μm.

[0017] In an embodiment, the thickness of the first friction layer is 0.1 mm to 0.5 mm, and the thickness of the second friction layer is 0.3 mm to 5 mm.

[0018] In an embodiment, the first surface comprises a plurality of first cracks, and the first cracks divide the first surface to form a plurality of first crack patch regions; the second surface comprises a plurality of second cracks, and the second cracks divide the second surface to form a plurality of second crack patch regions; and the area of at least part of the first crack patch regions is smaller than the area of the second crack patch regions.​​

[0019] In one implementation, the first crack patch area is 4mm 2 ~ 90mm 2 , and the second crack patch area is 9mm 2 ~ 220mm 2 .

[0020] In one implementation, the crack density of the first surface is 3 / cm ~ 20 / cm, and the crack density of the second surface is 2 / cm ~ 18 / cm.

[0021] In a second aspect, the application provides a manufacturing method of a brake disc, comprising: preparing a slurry from a precursor material of a friction layer, and brushing the slurry on a preform; solidifying and sintering the slurry on the preform to obtain the brake disc; the precursor material of the friction layer is converted into the friction layer, and the preform is converted into a substrate, and the crack density of the second surface of the friction layer away from the substrate is less than the crack density of the first surface of the friction layer connected with the substrate.

[0022] In one implementation, preparing the slurry from the precursor material of the friction layer and brushing the slurry on the preform comprises: preparing a first slurry from first silicon carbide particles, brushing the first slurry on the preform and drying to obtain a first layer; preparing a second slurry from second silicon carbide particles, brushing the second slurry on the first layer and drying to obtain a second layer.

[0023] In a third aspect, the application provides a vehicle comprising the brake disc of the first aspect.

[0024] The application sets the friction layer on the surface of the substrate of the brake disc, and sets the crack density of the second surface of the friction layer away from the substrate to be less than the crack density of the first surface of the friction layer connected with the substrate, to avoid the material in the friction layer on the second surface away from the substrate from peeling off; meanwhile, since the first surface is the inner layer structure of the friction layer (connected with the substrate), even if there are more cracks on the first surface, the material on the first surface will not peel off, so that the overuse of the material on the first surface can be reduced, and the manufacturing cost of the brake disc is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0026] Fig. 1 is a schematic cross-sectional view of a brake disc in one implementation;

[0027] FIG. 2 is a schematic view of a cross-sectional dimension of a brake disc according to an embodiment;

[0028] FIG. 3 is a schematic view of a first crack patch area and a second crack patch area according to an embodiment;

[0029] FIG. 4 is a flowchart of a manufacturing process of a brake disc according to an embodiment;

[0030] FIG. 5 is a flowchart of step S10 according to an embodiment;

[0031] FIG. 6 is a flowchart of step S20 according to an embodiment;

[0032] FIG. 7 is a schematic view of a second face of a brake disc after a patch has fallen off.

[0033] BRIEF DESCRIPTION OF DRAWINGS 10 - base, 20 - friction layer, 21 - first friction layer, 22 - second friction layer, 201 - first face, 202 - second face, 203 - first crack, 204 - second crack, 205 - first crack patch area, 206 - second crack patch area. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0035] It should be noted that when a component is referred to as being "fixed" to another component, it can be directly on the other component or there can be an intervening component. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or there can be an intervening component.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The use of the terms "and / or" includes a combination of one or more of the associated listed items.

[0037] Some embodiments of the present application will be described in detail with reference to the drawings, wherein the same or like components are denoted by the same reference numerals, and components thereof will not be repeatedly described. In the case of no conflict, the following examples and features of the examples can be combined with each other.

[0038] The application provides a brake disc, and the specific type of the brake disc is a carbon ceramic brake disc. Referring to FIG. 1, the brake disc comprises a base body 10 and a friction layer 20, the friction layer 20 comprises a first face 201 and a second face 202 opposite to each other, the first face 201 is connected to the base body 10, and the first face 201 and the second face 202 are both provided with cracks, and the crack density of the second face 202 is less than that of the first face 201.

[0039] Specifically, the base body 10 is made of carbon ceramic material, and by arranging the friction layer 20 on the surface of the carbon ceramic base body 10, the friction coefficient of the carbon ceramic brake disc can be improved to meet the requirement of long service life. The friction layer 20 can comprise silicon carbide and silicon, and the main component is silicon carbide.

[0040] Since the friction layer 20 is arranged on the surface of the base body 10 to form a coating structure, the friction layer 20 can comprise the first face 201 and the second face 202 opposite to each other, wherein the first face 201 is connected to the base body 10, and the second face 202 is opposite to the base body 10. It can be understood that the second face 202 is a face facing the outside, and the braking effect is mainly achieved by friction of the second face 202. The crack density of the second face 202 is less than that of the first face 201.

[0041] It needs to be explained that, during the process of firing the carbon ceramic brake disc, due to the mismatch of the thermal expansion coefficients between the silicon carbide and the base body 10, cracks will be generated in the friction layer 20, and the cracks will extend from the inside of the friction layer 20 to the surface (i.e., the first face 201 and the second face 202) of the friction layer 20, so that cracks are also formed on the first face 201 and the second face 202. If the cracks on the upper surface (i.e., the second face 202) of the friction layer 20 are too dense, the bonding ability of the friction layer 20 and the base body 10 will be reduced, and small pieces will be easily peeled off during work; and if the crack density of the upper surface (i.e., the second face 202) is low, it often means that the content of silicon carbide in the friction layer 20 is insufficient, resulting in a low friction coefficient of the brake disc.

[0042] It needs to be explained that the base body 10 is in the shape of a circular ring, and comprises two large faces opposite to each other, and the friction layer 20 needs to be arranged on both large faces. In addition, the structural parameters of the friction layer 20 arranged on the two large faces are the same, that is, the friction layers 20 on both sides of the brake disc are distributed in mirror symmetry with the base body as the mirror. Therefore, for the convenience of description, only one of the large faces will be taken as an example for description in the following text, that is, one of the large faces is connected to the first face 201; and the cross-sectional view of the brake disc shown in FIG. 1 is also only a partial cross-section (one of the large faces) of the brake disc.

[0043] The application sets the friction layer 20 on the surface of the base body 10 of the brake disc, and sets the crack density on the second surface 202 of the friction layer 20 away from the base body 10 to be less than the crack density on the first surface 201 connected with the base body 10, so as to avoid the material in the friction layer 20 away from the base body 10 from peeling off; meanwhile, since the first surface 201 is the inner layer structure of the friction layer 20 (connected with the base body 10), even if there are more cracks on the first surface 201, the material on the first surface 201 will not peel off, so as to reduce the overuse of the material on the first surface 201 and reduce the manufacturing cost of the brake disc.

[0044] In an embodiment, referring to FIG. 1, the friction layer 20 includes a first friction layer 21 and a second friction layer 22, the first friction layer 21 is arranged on the base body 10, the first surface 201 is a surface of the first friction layer 21 away from the second friction layer 22, the second friction layer 22 is arranged on a surface of the first friction layer 21 away from the base body 10, the second surface 202 is a surface of the second friction layer 22 away from the first friction layer 21, and the crack density of the second friction layer 22 is less than the crack density of the first friction layer 21.

[0045] Specifically, the friction layer 20 is divided into two layers, i.e., the first friction layer 21 and the second friction layer 22, wherein the first friction layer 21 is connected with the base body 10, the second friction layer 22 is connected with the first friction layer 21, the first friction layer 21 includes the first surface 201, and the second friction layer 22 includes the second surface 202. In specific embodiments, the first friction layer 21 and the second friction layer 22 can be respectively manufactured, i.e., a precursor layer of the first friction layer 21 is first manufactured on the base body 10, then a precursor layer of the second friction layer 22 is manufactured on the first friction layer 21, and after common sintering, the complete friction layer 20 is obtained.

[0046] It can be understood that, since the first friction layer 21 and the second friction layer 22 are respectively manufactured, the parameters of silicon carbide (including particle size and content) in the first friction layer 21 and the second friction layer 22 can be configured to control the crack density in the first friction layer 21 and the second friction layer 22. The crack density in the first friction layer 21 includes the crack density on the first surface 201, and the crack density in the second friction layer 22 includes the crack density on the second surface 202.

[0047] In an embodiment, the first friction layer 21 includes first silicon carbide particles, and the second friction layer 22 includes second silicon carbide particles, and the particle size of the second silicon carbide particles is greater than the particle size of the first silicon carbide particles. Specifically, the first friction layer 21 and the second friction layer 22 both include silicon carbide particles, wherein the first silicon carbide particles are in the first friction layer 21, and the second silicon carbide particles are in the second friction layer 22.

[0048] The first friction layer 21 is made of the first silicon carbide particles with small particle size. The first silicon carbide particles with small particle size have better toughness than the second silicon carbide particles with large particle size. Therefore, the cracks generated at the interface between the first friction layer 21 and the base 10 deflect on the surface of the first silicon carbide particles. Through this effect, the cracks gradually decrease in the direction from the first friction layer 21 to the second friction layer 22. When the cracks extend to the second friction layer 22, the second friction layer 22 has poor toughness due to the influence of the second silicon carbide particles. Therefore, the cracks do not deflect but extend straight through the second silicon carbide particles to the second surface 202 and finally form the required crack distribution density. In addition, the second silicon carbide particles have large friction coefficient and good wear resistance. After forming the cracks with appropriate size, the working stability and service life of the brake disc are greatly improved.

[0049] In an embodiment, the particle size of the first silicon carbide particles is 0.3 μm to 50 μm, and the particle size of the second silicon carbide particles is 50 μm to 200 μm. Optionally, the particle size of the first silicon carbide particles can be 0.3 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm. The particle size of the second silicon carbide particles can be 50 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, or 200 μm.

[0050] In an embodiment, the first friction layer 21 includes the first silicon carbide particles, and the second friction layer 22 includes the second silicon carbide particles. The mass fraction of the second silicon carbide particles in the second friction layer 22 is greater than the mass fraction of the first silicon carbide particles in the first friction layer 21.

[0051] The content of the first silicon carbide particles in the first friction layer 21 is less than the content of the second silicon carbide particles in the second friction layer 22. When the cracks generated at the interface between the first friction layer 21 and the base 10 extend to the second friction layer 22, the cracks do not deflect but extend straight through the second silicon carbide particles to the second surface 202 due to the influence of the content of the second silicon carbide particles, and finally form the required crack distribution density.

[0052] In an embodiment, the mass percentage of the first silicon carbide particles in the first friction layer 21 is 50% to 80%, and the mass percentage of the second silicon carbide particles in the second friction layer 22 is 70% to 95%. Optionally, the mass percentage of the first silicon carbide particles in the first friction layer 21 is 50%, 55%, 60%, 65%, 70%, 75%, 80%, and the mass percentage of the second silicon carbide particles in the second friction layer 22 is 70%, 75%, 80%, 85%, 90%, 95%. The mass percentage of the first silicon carbide particles in the first friction layer 21 is within the above range, so as to control the content of the first silicon carbide within a suitable range, control the crack density in the first friction layer 21, avoid excessive crack density in the first friction layer 21, or avoid excessive reduction of the performance of the friction layer 20 due to the small amount of the first silicon carbide particles.

[0053] In an embodiment, the thickness of the first friction layer 21 is 0.1 mm to 0.5 mm, and the thickness of the second friction layer 22 is 0.3 mm to 5 mm. Optionally, the thickness of the first friction layer 21 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, and the thickness of the second friction layer 22 can be 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm. The thickness of the first friction layer 21 is within the above range, so as to avoid excessive thickness or thinness of the friction layer as a whole, and also to cooperate with the particle size of the first silicon carbide particles. If the first friction layer 21 is too thin, the content of the first silicon carbide particles will be too small, and vice versa.

[0054] In an embodiment, the crack width in the first friction layer 21 is 2 μm to 30 μm, and the crack width in the second friction layer 22 is 10 μm to 80 μm. Optionally, the crack width in the first friction layer 21 can be 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, and the crack width in the second friction layer 22 can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm. The crack width in the first friction layer 21 and the crack width in the second friction layer 22 are within the above range, so as to avoid damage to the friction layer as a whole, and control the amount of silicon carbide particles to ensure that the friction layer 20 fully functions. If the crack width in the first friction layer 21 and the second friction layer 22 is too narrow, the amount of silicon carbide particles is too small, so that the friction layer 20 cannot function accordingly. If the crack width is too wide, the stability of the friction layer 20 will be poor, there are many defects on the friction layer 20, and the service life of the friction layer 20 is limited.

[0055] In an embodiment, the average crack spacing λ f1is 2mm-9mm. The average crack interval λ f2 is 3mm-14mm. Optionally, λ f1 may be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm; λ f2 may be 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm. The average crack interval λ f1 at the first surface 201 and the average crack interval λ f2 at the second surface 202 are satisfied. Within the above range, the average crack interval λ

[0056] In an embodiment, the average crack interval λ f1 satisfies the following relationship: V TSiC is the content of the first silicon carbide particles in the first friction layer 21, and α is the crack interval base number of the first friction layer 21, and the value range of α is 0.3mm-0.7mm.

[0057] It should be noted that the average crack interval λ f1 at the first surface 201 is affected by the content of the first silicon carbide particles, and in order to control the average crack interval λ f1 at the first surface 201, the content of the first silicon carbide particles in the first friction layer 21 is adjusted according to the relationship provided in the above embodiment, so that the average crack interval λ f1 at the first surface 201 of the brake disc produced is within the required range. Therefore, the present application is to provide a relationship for pre-calculating the average crack interval λ f1 at the first surface 201, and by using the relationship to adjust the content of the first silicon carbide particles in the first friction layer 21 before manufacturing the brake disc, the production difficulty of the brake disc in the production process is reduced, and the average crack interval λ f1 is constrained to avoid the actual crack interval exceeding the above provided range, and the yield is improved.

[0058] In an embodiment, the average crack interval λ f2The relationship is satisfied:

[0059] V SSiC The content of the second silicon carbide particles in the second friction layer 22 is δ, and δ is in the range of 0.36mm to 1mm. Similarly, the average crack spacing λ2 at the second surface 202 is set to satisfy the relationship: f2 The purpose of satisfying the above relationship is to balance the content of the second silicon carbide particles in the second friction layer 22 to control the average crack spacing λ2. h2 In the above range, the specific values can be referred to the above description, which will not be repeated here.

[0060] In an embodiment, the average crack spacing λ1 in the first friction layer 21 is in the range of 2mm to 9mm, and the average crack spacing λ2 in the second friction layer 22 is in the range of 3mm to 14mm. h1 h2 In an embodiment, the average crack spacing λ1 in the first friction layer 21 is in the range of 2mm to 9mm, and the average crack spacing λ2 in the second friction layer 22 is in the range of 3mm to 14mm. h1 In an embodiment, the average crack spacing λ1 in the first friction layer 21 is in the range of 2mm to 9mm, and the average crack spacing λ2 in the second friction layer 22 is in the range of 3mm to 14mm. h2 In an embodiment, the average crack spacing λ1 in the first friction layer 21 is in the range of 2mm to 9mm, and the average crack spacing λ2 in the second friction layer 22 is in the range of 3mm to 14mm. h1 In an embodiment, the average crack spacing λ1 in the first friction layer 21 is in the range of 2mm to 9mm, and the average crack spacing λ2 in the second friction layer 22 is in the range of 3mm to 14mm. h2 The above ranges are to avoid the case that the crack density is too large due to too close crack spacing, and to control the amount of silicon carbide particles to ensure that the friction layer 20 fully functions. When the average crack spacing in the first friction layer 21 and the second friction layer 22 is too close, it means that the crack density is increased, the stability of the friction layer 20 is poor, there are more defects on the friction layer 20, and the service life of the friction layer 20 is limited. When the average crack spacing in the first friction layer 21 and the second friction layer 22 is too far, it means that the amount of silicon carbide particles is too small, so that the friction layer 20 cannot function as expected.

[0061] In an embodiment, the average crack spacing λ1 in the first friction layer 21 is in the range of 2mm to 9mm, and the average crack spacing λ2 in the second friction layer 22 is in the range of 3mm to 14mm. h1 The relationship is satisfied:

[0062] Wherein, h T is the thickness of the first friction layer 21, h1 is the shortest distance between the crack in the first friction layer 21 and the substrate 10, β is the specific stiffness coefficient of the friction layer 20, σ max is the residual thermal stress at the connection between the friction layer 20 and the substrate 10, E r ​Δα is the Young's modulus of friction layer 20, L is the reference distance for horizontal deflection of the crack, Δα is the difference in thermal expansion coefficients between friction layer 20 and substrate 10, and ΔT is the difference between silicon diffusion temperature and room temperature.

[0063] Optionally, the thickness h of the first friction layer 21 T The above implementation method can be referred to, and will not be repeated here. It should be explained that this formula is used to calculate the average spacing λ between cracks in the first friction layer 21. h1 h1 is the shortest distance between the crack at the first friction layer 21 and the substrate 10, as shown in Figure 2.

[0064] Optionally, the specific stiffness coefficient β of the friction layer 20 refers to the ratio of the elastic modulus of the material to its density, also known as "specific modulus" or "specific elastic modulus".

[0065] It should be noted that the average crack spacing λ of the first friction layer 21 h1 It will be affected by the above parameters, but in reality, it is affected by the material's own properties (such as the material's modulus, content, and the required thickness of the first friction layer 21). Before the actual production of the brake disc, in order to control the average crack spacing λ of the first friction layer 21... h1 Within the range provided in the above embodiments, the average crack spacing λ of the produced brake disc can be ensured by adjusting the values ​​of the above parameters. h1 Within the required range. Furthermore, it is evident from the above relationship that the average crack spacing λ of the first friction layer 21 is... h1 The crack spacing λ of the first friction layer 21 is directly proportional to some parameters and inversely proportional to others. Therefore, by strictly controlling the values ​​of each parameter, the required average crack spacing λ of the first friction layer 21 can be obtained. h1 .

[0066] Therefore, this application aims to provide a method for facilitating the pre-calculation of the average crack spacing λ of the first friction layer 21. h1 The formula is used to determine the parameters of the friction layer before manufacturing the brake disc, thereby reducing the manufacturing difficulty of the brake disc and constraining the average crack spacing λ. h1 This helps prevent the actual crack spacing from exceeding the range provided above, thereby improving the yield rate.

[0067] In one embodiment, referring to FIG2, the average crack spacing λ in the second friction layer 22 h2 Satisfying the relation:

[0068] Among them, h S h1 is the thickness of the second friction layer 22, and h2 is the shortest distance between the crack in the second friction layer 22 and the substrate 10.

[0069] Optionally, the thickness h of the second friction layer 22 S The above implementation method can be referred to, and will not be repeated here. It should be explained that this formula is used to calculate the average spacing λ between cracks in the second friction layer 22. h2 h2 is the shortest distance between the crack in the second friction layer 22 and the substrate 10, which needs to be calculated; as shown in Figure 2, this distance should be greater than h1 mentioned above. Similarly, the average crack spacing λ in the second friction layer 22 is set. h2 Satisfying the above relationship is to balance the proportions of various parameters in the second friction layer 22, so as to control the average crack spacing λ. h2 For details regarding the purposes within the aforementioned scope, please refer to the above explanation; further details will not be elaborated upon here.

[0070] In one implementation, Where p is the Poisson's ratio of the friction layer 20, and E S For Young's modulus of matrix 10, t S The thickness of the substrate is 1 / 2, h R This represents the original thickness of the second friction layer 22 after silicon infiltration.

[0071] Optionally, Poisson's ratio refers to the ratio of transverse normal strain to axial normal strain when a material is under uniaxial tension or compression; it is also called the transverse deformation coefficient. It is an elastic constant reflecting the transverse deformation of the material. The Poisson's ratio of silicon and silicon carbide (the Poisson's ratio of friction layer 20) is around 0.2. In one embodiment, h R The diameter is 1mm to 4mm.

[0072] It should be noted that in the calculation of residual thermal stress at the junction of friction layer 20 and substrate 10, the thickness of the second friction layer 22 before silicon diffusion and processing needs to be considered. The second friction layer 22 can be processed to different sizes after silicon diffusion, but the residual thermal stress at the junction of friction layer 20 and substrate 10 will not change with the processed dimensions (residual stress has already been generated during cooling and has caused the friction layer 20 to crack). Therefore, the residual stress should be calculated using the thickness of the second friction layer 22 before processing (generally, the processing allowance is 0.5mm to 1.5mm, i.e., h). R Compared to h S (0.5mm to 1.5mm).

[0073] In one embodiment, the residual thermal stress σ at the junction of the friction layer 20 and the substrate 10 max The pressure ranges from 100 MPa to 500 MPa. Optionally, the residual thermal stress σ at the junction of the friction layer 20 and the substrate 10... max It can be 100MPa, 200MPa, 300MPa, 400MPa, or 500MPa.

[0074] satisfying the residual thermal stress σ max In the above range, it is to ensure the average crack spacing λ h2 and the average crack spacing λ h1 In the above range. It can be understood that, based on the above average crack spacing λ h2 and the relationship of the average crack spacing λ h1 The residual thermal stress σ max is inversely proportional to both, so for the control of the average crack spacing (i.e. crack density), it is necessary to strictly control the value range of the residual thermal stress σ max . And the residual thermal stress σ max is affected by the substrate 10 and the properties of the silicon carbide particles themselves, so it can be achieved by controlling the parameters of the substrate 10 and the silicon carbide particles to control the purpose of the residual thermal stress σ max By the above relationship, the production difficulty of the brake disc in the production process can be reduced, and the yield can be improved.

[0075] In one embodiment, the first friction layer 21 further comprises first silicon particles, and the second friction layer 22 further comprises second silicon particles, Wherein, E SiC is the Young's modulus of silicon carbide, E Si is the Young's modulus of silicon, V TSiC is the content of the first silicon carbide particles in the first friction layer 21, V TSi is the content of the first silicon particles in the first friction layer 21, V SSiC is the content of the second silicon carbide particles in the second friction layer 22, V SSi is the content of the second silicon particles in the second friction layer 22.

[0076] In one embodiment, the Young's modulus E SiC of silicon carbide is about 300GPa-700GPa, and the Young's modulus E Si of silicon is about 90GPa-150GPa. The content V TSiC of the first silicon carbide particles in the first friction layer 21 and the content V SSiC of the second silicon carbide particles in the second friction layer 22 can refer to the above embodiment, and will not be repeated here. Since the friction layer 20 only includes silicon carbide and silicon, the content V TSi of the first silicon particles in the first friction layer 21 can be calculated by the content of the first silicon carbide particles, and the content V SSi of the second silicon particles can be calculated in the same way.

[0077] In one embodiment, Wherein, α SUBis the thermal expansion coefficient of the base 10, and is 1 x 10^ -6 / °C, α Si is the thermal expansion coefficient of silicon, and is 2.5 x 10^ SiC is the thermal expansion coefficient of silicon carbide.

[0078] In one embodiment, the thermal expansion coefficient of silicon α Si is approximately 2.5 x 10^ -6 / °C to 3.0 x 10^ -6 / °C, the thermal expansion coefficient of silicon carbide α SiC is approximately 4.4 x 10^ -6 / °C.

[0079] In one embodiment, the specific rigidity coefficient β of the friction layer 20 is 1500-7000. Alternatively, the specific rigidity coefficient β of the friction layer 20 can be 1500, 2000, 3000, 4000, 5000, 6000, or 7000.

[0080] In one embodiment, the reference distance L of the horizontal deflection of the crack is 1 mm-4 mm. Alternatively, the reference distance L of the horizontal deflection of the crack can be 1 mm, 2 mm, 3 mm, or 4 mm. The reference distance L of the horizontal deflection of the crack is within the above range so as to avoid excessive horizontal deflection of the crack. Excessive horizontal deflection of the crack will result in excessive extension of the crack texture in the friction layer 20, and the horizontal deflection of the crack will affect the stability of the friction layer 20. Therefore, controlling the reference distance L of the horizontal deflection of the crack within the above range can improve the structural stability of the friction layer 20.

[0081] In one embodiment, referring to FIG. 3, the gap width of the crack on the first surface 201 is smaller than the gap width of the crack on the second surface 202.

[0082] Specifically, during the firing of the carbon ceramic brake disc, a large number of cracks will be generated in the friction layer 20 due to the mismatch of the thermal expansion coefficients between the silicon carbide and the base 10. In addition, the width of the cracks will vary due to the different contents of the silicon carbide. If the cracks on the upper surface (i.e., the second surface 202) of the friction layer 20 are too wide, the strength and the bonding ability of the friction layer 20 will be reduced, and small pieces will be easily peeled off during operation. If the cracks on the upper surface (i.e., the second surface 202) are too narrow, it means that the content of the silicon carbide in the friction layer 20 is insufficient, and the friction coefficient of the brake disc will be low.

[0083] It should be explained that in the embodiment, the gap width of the crack on the first surface 201 can refer to the crack width in the first friction layer 20 in the above embodiment; the gap width of the crack on the second surface 202 can refer to the crack width in the second friction layer 20 in the above embodiment. However, it should be explained that the first surface 201 is the surface of the first friction layer 20, so the gap width of the crack on the first surface 201 can be different from the crack width in the first friction layer 20, or the range of the gap width of the crack on the first surface 201 can be different from the range of the crack width in the first friction layer 20; the second surface 202 is the surface of the second friction layer 20, so the gap width of the crack on the second surface 202 can be different from the crack width in the second friction layer 20, or the range of the gap width of the crack on the second surface 202 can be different from the range of the crack width in the second friction layer 20.

[0084] The application sets the friction layer 20 on the surface of the base body 10 of the brake disc, and sets the gap width of the crack on the first surface 201 to be smaller than the gap width of the crack on the second surface 202, so as to ensure that the amount of silicon carbide particles at the second surface 202 facing away from the base body 10 can fully play a role, and ensure that the friction coefficient at the second surface 202 is higher; and the material suitable for the first surface 201 can also be saved. Since the first surface 201 is the inner structure (connected with the base body 10) of the friction layer 20, even if the crack width on the first surface 201 is small, the amount of silicon carbide particles is small, which can reduce the overuse of the material at the first surface 201 and reduce the manufacturing cost of the brake disc.

[0085] In an embodiment, the gap width of the crack on the first surface 201 is 0.1 μm to 4 μm, and the width of the crack on the second surface 202 is 1 μm to 10 μm. Optionally, the gap width of the crack on the first surface 201 can be 0.1 μm, 0.4 μm, 0.8 μm, 1.2 μm, 1.6 μm, 2 μm, 2.4 μm, 2.8 μm, 3.2 μm, 3.6 μm, or 4 μm. The width of the crack on the second surface 202 can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm. The gap width of the crack on the first surface 201 and the gap width of the crack on the second surface 202 are within the above range, so as to avoid damaging the whole friction layer 20 and control the amount of silicon carbide particles to ensure that the friction layer 20 fully plays a role. When the gap width of the crack on the first surface 201 and the second surface 202 is too narrow, it means that the amount of silicon carbide particles is too small, so that the friction layer 20 cannot play a corresponding role; if the crack width is too wide, the stability of the friction layer 20 will be poor, there are more defects on the friction layer 20, and the service life of the friction layer 20 is limited.

[0086] In one embodiment, referring to FIG. 3, the first surface 201 includes a plurality of first cracks 203, and the first cracks 203 divide the first surface 201 into a plurality of first crack patch regions 205; the second surface 202 includes a plurality of second cracks 204, and the second cracks 204 divide the second surface 202 into a plurality of second crack patch regions 206; the area of at least some of the first crack patch regions 205 is less than the area of the second crack patch regions 206.

[0087] Specifically, as shown in FIG. 3a, the first surface 201 includes a plurality of first cracks 203 intersecting each other, so the first cracks 203 can divide the first surface 201 into a plurality of regions of different sizes and shapes, and all the regions divided on the first surface 201 are collectively referred to as first crack patch regions 205. As shown in FIG. 3b, the second surface 202 includes a plurality of second cracks 204 intersecting each other, so the second cracks 204 can divide the second surface 202 into a plurality of regions of different sizes and shapes, and all the regions divided on the second surface 202 are collectively referred to as second crack patch regions 206.

[0088] It can be understood that, because the crack density on the first surface 201 is different from the crack density on the second surface 202, and the crack density on the second surface 202 is less than the crack density on the first surface 201. Therefore, there are fewer second crack patch regions 206 divided on the second surface 202, and there are more first crack patch regions 205 divided on the first surface 201. Therefore, when the area of the first surface 201 and the area of the second surface 202 are the same, the area of the second crack patch regions 206 is greater than the area of the first crack patch regions 205. In this way, the crack density on the first surface 201 and the crack density on the second surface 202 can also be obtained from the number and area of the second crack patch regions 206. The difference in crack density can be intuitively obtained from the area of the first crack patch regions 205 and the area of the second crack patch regions 206. In the case where the area of the first crack patch regions 205 is small and the number of regions is large, the material at the first surface 201 will not be peeled off, thereby reducing the overuse of the material at the first surface 201 and reducing the manufacturing cost of the brake pad.

[0089] In one embodiment, the area of the first crack patch regions 205 is 4mm 2 ~ 90mm 2 , and the area of the second crack patch regions 206 is 9mm 2 ~ 220mm 2 . Optionally, the area of the first crack patch regions 205 can be 4mm 2 , 10mm 2 , 20mm 2 , 30mm 2 , 40mm 2 , 50mm2 60mm 2 70mm 2 80mm 2 90mm 2 The area of the second crack patch area 206 is 9mm 2 20mm 2 30mm 2 50mm 2 70mm 2 100mm 2 150mm 2 200mm 2 220mm 2 By satisfying the area of the first crack patch area 205 and the area of the second crack patch area 206 in the above range, it can be ensured that the second crack patch area 206 has a larger area, and the second crack patch area 206 is not easy to fall off in the process of long-term use; and the first crack patch area 205 has a small area, so that even in the case of many cracks on the first surface 201, the material at the first surface 201 will not peel off.

[0090] In an embodiment, the crack density of the first surface 201 is 3-20 cracks / cm, and the crack density of the second surface 202 is 2-18 cracks / cm; wherein the crack density of the second surface 202 is 1-6 cracks / cm lower than the crack density of the first surface 201.

[0091] Optionally, the crack density of the first surface 201 can be 3, 4, 6, 8, 10, 12, 14, 16, 18, 20 cracks / cm. The crack density of the second surface 202 is 2, 4, 6, 8, 10, 12, 14, 16, 18 cracks / cm.

[0092] It can be understood that by setting the crack density on the second surface 202 to be less than the crack density on the first surface 201 connected to the base 10, the material in the friction layer 20 at the second surface 202 facing away from the base 10 can be prevented from peeling off; at the same time, since the first surface 201 is the inner layer structure of the friction layer 20 (connected to the base 10), even in the case of many cracks on the first surface 201, the material at the first surface 201 will not peel off, thereby reducing the overuse of the material at the first surface 201 and reducing the manufacturing cost of the brake pad.

[0093] In an embodiment, the application also provides a manufacturing method of the brake disc, please refer to Fig. 4, which specifically comprises:

[0094] Step S10, the precursor material of the friction layer is made into a slurry, and the slurry is brushed on the preform.

[0095] Step S20, the preform is obtained by curing and sintering the slurry on the preform.

[0096] The precursor material of the friction layer is converted into the friction layer, the preform is converted into the substrate, and the crack density of the friction layer on the back of the substrate is less than the crack density at the joint of the friction layer and the substrate.

[0097] In one embodiment, referring to FIG. 5, the step of making the precursor material of the friction layer into a slurry and brushing the slurry on the preform includes:

[0098] Step S11, the first silicon carbide particles are made into a first slurry, the first slurry is brushed on the preform and dried to obtain a first layer.

[0099] Step S12, the second silicon carbide particles are made into a second slurry, the second slurry is brushed on the first layer and dried to obtain a second layer.

[0100] In one embodiment, in step S11, the first silicon carbide particles are made into a first slurry, specifically including: mixing the first silicon carbide particles, phenolic resin powder and alcohol, the particle size of the first silicon carbide particles is 0.3-50 μm, the content of the first silicon carbide particles is 40-60%, the content of the phenolic resin powder is 10-50%, and the content of the alcohol is 30-40%, to obtain the first slurry.

[0101] In one embodiment, in step S11, the first slurry is brushed on the preform and dried to obtain a first layer, specifically including: brushing the first slurry on the upper and lower surfaces of the preform, and placing it in a 60°C oven to completely dry the alcohol, to obtain the first layer.

[0102] In one embodiment, in step S12, the second silicon carbide particles are made into a second slurry, specifically including: mixing the second silicon carbide particles, phenolic resin powder and alcohol, the particle size of the second silicon carbide particles is 50-200 μm, the content of the second silicon carbide particles is 30-50%, the content of the phenolic resin powder is 10-50%, and the content of the alcohol is 30-40%, to obtain the first slurry.

[0103] In one embodiment, in step S12, the second slurry is brushed on the first layer and dried to obtain a second layer, specifically including: brushing the second slurry on the upper and lower surfaces of the first layer, and placing it in a 60°C oven to completely dry the alcohol, to obtain the second layer.

[0104] In one embodiment, referring to FIG. 6, the preform is obtained by curing and sintering the slurry on the preform, including:

[0105] Step S21, curing the preform with the first layer and the second layer, and then carbonizing the preform in a carbonization furnace to obtain a carbonized blank.

[0106] Step S22, treating the carbonized blank, and then performing liquid silicon infiltration to obtain a carbon ceramic blank.

[0107] Step S23, machining the surface and the side surface of the carbon ceramic blank to obtain the brake disc.

[0108] In one embodiment, in step S21, curing the preform with the first layer and the second layer specifically comprises: curing the preform with the first layer and the second layer at 150°C for 2h-3h.

[0109] In one embodiment, in step S21, carbonizing in the carbonization furnace specifically comprises: placing the cured preform into the carbonization furnace for carbonization, and the carbonization temperature is 1000°C, and the holding time is 2h-4h.

[0110] In one embodiment, in step S22, treating the carbonized blank, and then performing liquid silicon infiltration to obtain a carbon ceramic blank, wherein the thickness h of the second friction layer in the carbon ceramic blank is 1mm-4mm. R h R The value of h can refer to the above embodiments, and will not be described here.

[0111] In one embodiment, the application further provides a vehicle comprising the brake disc provided in the above embodiments.

[0112] The technical solutions of the application are described in detail below through specific embodiments, and the data of each embodiment is shown in Table 1.

[0113] Table 1

[0114] In Table 1, the size of the dropped patch of the brake disc is that after the brake disc is used, a patch will drop from the second surface of the brake disc due to the existence of a crack, and a hole will be formed on the second surface after the patch drops (see FIG. 7), and the shaded part in the figure is the hole, and the size of the dropped patch in the above description is the opening area of the hole, so the unit is "cm 2 ". Based on the data in Table 1, it can be found that the size of the dropped patch of the brake disc provided in Examples 1-7 is smaller than that of Comparative Example 1, so it is proved that the brake disc provided in the application can solve the problem of peeling of the friction layer.

[0115] In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like, indicate the orientation or positional relationship based on the drawings described in the application, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0116] The above only discloses a preferred embodiment of the present application, of course cannot limit the scope of the present application, those skilled in the art can understand that the implementation of all or part of the above-mentioned process, and the equivalent changes made by the claims of the present application, still belong to the scope covered by the present application.

Claims

1. A brake disc, comprising a base body (10) and a friction layer (20), the friction layer (20) comprising a first face (201) and a second face (202) opposite to each other, the first face (201) being connected to the base body (10), and the second face (202) having a crack density less than that of the first face (201).

2. The brake disc of claim 1, wherein, The friction layer (20) comprises a first friction layer (21) and a second friction layer (22), the first friction layer (21) being arranged on the base body (10), and the second friction layer (22) being arranged on a face of the first friction layer (21) opposite to the base body (10), the first face (201) being a face of the first friction layer (21) opposite to the second friction layer (22), the second face (202) being a face of the second friction layer (22) opposite to the first friction layer (21), and the second friction layer (22) having a crack density less than that of the first friction layer (21).

3. The brake disc of claim 2, wherein, The first friction layer (21) comprises first silicon carbide particles, and the second friction layer (22) comprises second silicon carbide particles, the second silicon carbide particles having a particle size greater than that of the first silicon carbide particles.

4. The brake disc of claim 3, wherein, The first silicon carbide particles have a particle size of 0.3 μm to 50 μm, and the second silicon carbide particles have a particle size of 50 μm to 200 μm.

5. A brake disc according to any one of claims 2 to 4 wherein, The first friction layer (21) comprises first silicon carbide particles, and the second friction layer (22) comprises second silicon carbide particles, the second silicon carbide particles having a mass percentage in the second friction layer (22) greater than that of the first silicon carbide particles in the first friction layer (21).

6. The brake disc of any one of claims 2 to 5 wherein, The first silicon carbide particles have a mass percentage of 50% to 80% in the first friction layer (21), and the second silicon carbide particles have a mass percentage of 70% to 95% in the second friction layer (22).

7. A brake disc according to any one of claims 2 to 6, wherein The average crack spacing λ at the first surface (201) is f1 2 mm to 9 mm.

8. The brake disc of any one of claims 2 to 7, wherein, The λ f1 satisfies the relationship: V TSiC The content of the first silicon carbide particles in the first friction layer (21) is α, and the value of α is in the range of 0.3 mm to 0.7 mm.

9. The brake disc of any one of claims 2 to 8, wherein, The average crack spacing λ at the second surface (202) is f2 is 3 mm to 14 mm.

10. The brake disc of any one of claims 2 to 9, wherein, The λ f2 satisfies the relationship: V SSiC The content of the second silicon carbide particles in the second friction layer (22) is δ times the base crack spacing of the second friction layer (22), where δ is in the range of 0.36 mm to 1 mm.

11. A brake disc according to any one of claims 2 to 10, wherein, The first friction layer (21) has a crack width of 2 μm to 30 μm, and the second friction layer (22) has a crack width of 10 μm to 80 μm.

12. The brake disc of any one of claims 2 to 11, wherein, The first friction layer (21) has a thickness of 0.1 mm to 0.5 mm, and the second friction layer (22) has a thickness of 0.3 mm to 5 mm.

13. The brake disc of any one of claims 1 to 12, wherein, The first face (201) comprises a plurality of first cracks (203), the first cracks (203) dividing the first face (201) into a plurality of first crack patch areas (205), the second face (202) comprises a plurality of second cracks (204), the second cracks (204) dividing the second face (202) into a plurality of second crack patch areas (206), and at least part of the first crack patch areas (205) have an area less than that of the second crack patch areas (206).

14. The brake disc of claim 13, wherein, The first crack plaque area (205) has an area of 4 mm 2 ~ 90 mm 2 The second crack plaque area (206) has an area of 9 mm 2 ~ 220 mm 2 .

15. The brake disc of any one of claims 1 to 14, wherein, The first face (201) has a crack density of 3 cracks / cm to 20 cracks / cm, and the second face (202) has a crack density of 2 cracks / cm to 18 cracks / cm. 16.A method for manufacturing a brake disc, comprising: preparing a slurry of a precursor material of a friction layer, and brushing the slurry on a preform; The brake pad is obtained by curing and sintering the slurry on the preform; The precursor material of the friction layer is converted into the friction layer, and the preform is converted into the substrate, and the crack density of the friction layer on the back of the substrate is less than the crack density at the connection between the friction layer and the substrate.

17. The method of manufacturing according to claim 16, wherein, The precursor material of the friction layer is made into the slurry, and the slurry is brushed on the preform, which includes: The first silicon carbide particles are made into a first slurry, the first slurry is brushed on the preform and dried to obtain a first layer; The second silicon carbide particles are made into a second slurry, the second slurry is brushed on the first layer and dried to obtain a second layer.

18. A vehicle comprising the brake disc according to any one of claims 1-15.

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