Brake assembly, brake disc, wheel, and vehicle

Abstract

Disclosed are a brake assembly, a brake disc, a wheel, and a vehicle. The brake assembly comprises a disc cap (1), a connecting assembly (3) connected to the disc cap, and an elastic member (4); the elastic member comprises a radial floating part (41); and the radial floating part is arranged between the disc cap and the connecting assembly along the radial direction of the disc cap, and is elastically deformable along the radial direction of the disc cap. In this way, the brake assembly has a floating margin in the radial direction relative to the disc cap, and therefore, during braking, eccentric wear between the brake assembly and the disc cap caused by radial tilting of the brake assembly relative to the disc cap can be avoided, thereby reducing the mechanical damage to a brake disc (2), avoiding the noise generation, and prolonging the service life of the brake assembly.

Description

Braking components, brake discs, wheels and vehicle

[0001] This application claims priority to Chinese patent application No. 202422589555.6, filed on October 24, 2024; Chinese patent application No. 202411201722.3, filed on August 28, 2024; Chinese patent application No. 202411696751.1, filed on November 22, 2024; and Chinese patent application No. 202411391272.9, filed on September 30, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of braking technology, and more particularly to a braking assembly, brake disc, wheel, and vehicle. Background Technology

[0003] During vehicle braking, the driver presses the brake pedal, and the internal friction pads move and press against the brake discs of the wheels to clamp the brake discs, thereby generating a frictional torque that prevents the wheels from rotating, thus achieving braking. Summary of the Invention

[0004] This disclosure provides a braking assembly, a brake disc, a wheel, and a vehicle.

[0005] In a first aspect, a braking assembly is provided, comprising a disc cap, a connecting assembly, and an elastic member. The connecting assembly is connected to the disc cap. The elastic member includes a radially floating portion. The radially floating portion is disposed between the disc cap and the connecting assembly along the radial direction of the disc cap, and is elastically deformable along the radial direction of the disc cap.

[0006] In this way, during braking, the brake assembly has a radial floating margin relative to the disc cap, so as to avoid uneven wear between the brake assembly and the disc cap after the brake assembly is misaligned in the radial direction, thereby reducing mechanical damage to the brake disc, avoiding noise, and extending the service life of the brake assembly.

[0007] In some embodiments, the elastic deformation of the radial floating part along the radial direction of the disc cap is greater than or equal to 0.05 mm and less than or equal to 0.9 mm. This satisfies the radial floating requirement while ensuring structural compactness.

[0008] In some embodiments, the radial floating portion includes at least one elastic portion that is elastically deformable along the radial direction of the cap.

[0009] In some embodiments, the elastic portion can be elastically deformed in the radial direction away from the center of the disc cap; or, the elastic portion can be elastically deformed in the radial direction away from the center of the disc cap.

[0010] In some embodiments, the elastic portion includes a curved section that arches toward the center of the cap, such that the elastic portion is elastically deformable radially away from the center of the cap. Alternatively, the curved section arches away from the center of the cap, such that the elastic portion is elastically deformable radially toward the center of the cap.

[0011] In some embodiments, the radial floating portion includes at least one first elastic portion and at least one second elastic portion arranged alternately in sequence along the circumference of the disc cap. The first elastic portion includes a first curved section that arches towards the center of the disc cap. The second elastic portion includes a second curved section that arches away from the center of the disc cap.

[0012] In some embodiments, at least one first elastic portion includes two first elastic portions, and at least one second elastic portion includes one second elastic portion. Along the circumferential direction of the cap, one second elastic portion is located between the two first elastic portions.

[0013] In some embodiments, the first curved segment and the second curved segment have an arc shape, a crest shape, a Λ shape, an Ω shape, or a П shape in the shape of the first cross section. The first cross section is perpendicular to the axis of the cap.

[0014] In some embodiments, the radial floating portion is located on the side of the connecting assembly facing the center of the disc cap.

[0015] In some embodiments, the disc cap has a mounting hole, and the connecting assembly passes through the mounting hole. A radial floating portion is disposed between the edge of the mounting hole near the center of the disc cap and the connecting assembly.

[0016] In some embodiments, the elastic member further includes two connecting portions; the two connecting portions are arranged circumferentially spaced along the disc cap, and a radial floating portion is connected between the ends of the two connecting portions facing the center of the disc cap. Each of the two connecting portions has at least one axial floating portion, which is disposed between the disc cap and the connecting assembly and is elastically deformable along the axial direction of the disc cap.

[0017] In some embodiments, the at least one axial floating part includes two axial floating parts, which are respectively connected to the two ends of the connecting part in the axial direction of the disc cap.

[0018] In some embodiments, the thickness of either of the two axially floating parts is greater than or equal to 0.4 mm and less than or equal to 0.8 mm.

[0019] In some embodiments, the end of the connector facing the center of the cap is the first end. The end of the connector facing away from the center of the cap is the second end. Along the radial direction of the cap, the shortest distance between the second curved segment and the plane containing the second end is the first distance, and the maximum distance between the first curved segment and the plane containing the first end is the second distance. The ratio of the first distance to the second distance is greater than or equal to 3.72 and less than or equal to 22.54.

[0020] In some embodiments, one of the two connecting portions has a first limiting portion on its surface facing away from the other connecting portion. The first limiting portion is configured to engage with the disc cap to prevent the elastic element from separating from the disc cap radially.

[0021] In some embodiments, the first limiting portion is a limiting protrusion.

[0022] In some embodiments, the protrusion height of the first limiting portion is a first height, and the length of the connecting portion along the circumference of the cap is a first length. The ratio of the first height to the first length is greater than or equal to 1 / 6 and less than or equal to 1 / 3.

[0023] In some embodiments, one of the two axially floating parts has a second limiting portion on its surface facing the other axially floating part. The second limiting portion is configured to engage with the disc cap to prevent the elastic element from separating from the disc cap radially.

[0024] In some embodiments, the second limiting portion is a limiting protrusion.

[0025] In some embodiments, the protrusion height of the second limiting portion is the second height. The distance between the two axial floating portions is the third distance, and the ratio of the second height to the third distance is greater than or equal to 1 / 6 and less than or equal to 1 / 3.

[0026] In some embodiments, the elastic element includes at least one selected from steel elastic elements, iron elastic elements, aluminum alloy elastic elements, and ceramic elastic elements.

[0027] In a second aspect, a brake disc is provided, which includes a braking assembly and a brake disc as described in any of the above technical solutions, wherein the brake disc is connected to a connecting assembly of the braking assembly.

[0028] Since the brake disc includes the elastic element described above, both can solve the same problem and achieve the same effect.

[0029] Thirdly, a wheel is provided, which includes a hub and the aforementioned brake disc, with the disc cap fixed to the hub and arranged coaxially with the hub.

[0030] Since the wheel includes the brake disc described in the above technical solution, both can solve the same problem and achieve the same effect.

[0031] Fourthly, a vehicle is provided, the vehicle including a body and the aforementioned wheels, the wheels being connected to the body.

[0032] Since the vehicle includes the wheels described in the above technical solution, both can solve the same problem and achieve the same effect. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of some embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 is a structural diagram of a vehicle according to some embodiments;

[0035] Figure 2 is an exploded view of a brake disc according to some embodiments;

[0036] Figure 3 is a top view of the assembly structure of the brake components in the brake disc shown in Figure 2;

[0037] Figure 4 is a structural diagram of an elastic element according to some embodiments;

[0038] Figure 5 is a structural diagram of another elastic element according to some embodiments;

[0039] Figure 6 is a structural diagram of another elastic element according to some embodiments;

[0040] Figure 7 is a structural diagram of an aluminum-based composite according to some embodiments;

[0041] Figure 8 is a flowchart of a method for preparing an aluminum-based composite brake disc according to some embodiments;

[0042] Figure 9 is a structural diagram of an aluminum-based composite brake disc according to some embodiments;

[0043] Figure 10 is a structural diagram of another aluminum-based composite brake disc according to some embodiments;

[0044] Figure 11 is an electron microscope image of a sintered blank according to some embodiments.

[0045] Reference numerals: 100, Vehicle; 10, Body; 20, Wheel; 201, Hub; 202, Braking assembly; 203, Friction assembly; 1, Disc cap; 11, Mounting hole; 2, Brake disc; 21, Through hole; 3, Connecting assembly; 31, Bolt; 32, Limiting sleeve; 321, Intermediate part; 322, First stop part; 323, Second stop part; 33, Nut; 4, Elastic element; 41, Radial floating part; 411, First elastic part; 412, Second elastic part; 42, Connecting part; 43, Axial floating part; 44, First limiting part; 45, Second limiting part; 5-Auxiliary elastic element. 1000, Aluminum substrate; 2000, Friction layer; 2001, First sub-friction unit; 2002, Second sub-friction unit. Detailed Implementation

[0046] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.

[0047] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0048] [A, B] refers to any value from A to B.

[0049] Brake discs are typically connected to wheel caps via connecting components. In some braking scenarios, such as repeated braking or extreme conditions, the brake disc may become radially misaligned with the wheel cap. This can easily lead to uneven wear between the brake disc and the wheel cap, causing mechanical damage or noise to the brake disc, affecting its performance and shortening its service life.

[0050] This disclosure provides a vehicle in some embodiments, including but not limited to electric vehicles, fuel-powered vehicles, or hybrid vehicles.

[0051] Please refer to Figure 1. The vehicle 100 includes a body 10 and wheels 20. The wheels 20 are connected to the body 10 and are configured to enable the vehicle to move.

[0052] Please refer to Figure 1. The wheel 20 may include a hub 201, a brake disc 202, and a friction assembly 203. The brake disc 202 is fixedly connected to the hub 201 and is arranged coaxially with the hub 201. During the rotation of the hub 201, the brake disc 202 can be driven to rotate.

[0053] Friction assembly 203 is disposed on brake disc 202. During vehicle braking, when the driver presses the brake pedal, friction assembly 203 moves and presses against brake disc 202 to clamp brake disc 202, thereby generating a frictional torque that prevents wheel 20 from rotating, thus achieving braking.

[0054] The structure of brake disc 202 will be described in detail below.

[0055] Referring to Figure 2, the brake disc 202 includes a disc cap 1, a brake disc 2, a connecting assembly 3, and an elastic element 4. Referring to Figure 3, here, the disc cap 1, the connecting assembly 3, and the elastic element 4 constitute the brake assembly.

[0056] Referring to Figure 1 and Figure 2, when the brake disc 202 is applied to the wheel 20 shown in Figure 1, the disc cap 1 is fixed to the wheel hub 201, and the disc cap 1 and the wheel hub 201 are arranged coaxially. The connecting assembly 3 is connected to the disc cap 1, and the brake disc 2 is connected to the connecting assembly 3, so as to be connected to the disc cap 1 by means of the connecting assembly 3. During the braking process of the vehicle, the friction assembly 203 can press against the brake disc 2 of the brake disc 202 to achieve braking of the wheel 20.

[0057] In some embodiments, please continue to refer to Figure 2. The disc cap 1 is provided with a mounting hole 11, and the connecting component 3 passes through the mounting hole 11 and is connected to the disc cap 1.

[0058] In some embodiments, referring to FIG2, the connecting assembly 3 may include a connector and a limiting sleeve 32. The cap 1 has a mounting hole 11. The limiting sleeve 32 may include a middle portion 321 and a first stop portion 322 and a second stop portion 323 respectively connected to the two ends of the middle portion 321 along the axial direction of the cap 1. The middle portion 321 passes through the mounting hole 11, and the first stop portion 322 and the second stop portion 323 are respectively located on opposite sides of the cap 1. The first stop portion 322 and the second stop portion 323 are configured to prevent the limiting sleeve 32 from separating from the cap 1 along the axial direction of the cap 1.

[0059] The connector is connected to the limiting sleeve 32, and the brake disc 2 is connected to the connector.

[0060] In some embodiments, the connector may include a bolt 31 and a nut 33. The brake disc 2 is provided with a through hole 21, the bolt 31 passes through the through hole 21 and the limiting sleeve 32, and the limiting sleeve 32 is fixed to the brake disc 2 by means of the nut 33.

[0061] It should be noted that the aforementioned connectors may also be structures composed of screws, studs and nuts, snap-fit ​​components, riveting components, etc., and this disclosure does not limit them.

[0062] In some embodiments, referring to FIG2, the number of mounting holes 11 and the number of connecting components 3 can both be multiple. Multiple mounting holes 11 are arranged circumferentially along the disc cap 1, and multiple connecting components 3 are respectively disposed within the multiple mounting holes 11. Thus, by connecting the disc cap 1 and the brake disc 2 with multiple connecting components 3, it is possible to ensure balanced force distribution and to radially define the position of the disc cap 1 relative to the brake disc 2. Only one connecting component 3 is shown in FIG2.

[0063] In some embodiments, referring to FIG2, the mounting hole 11 may extend radially through the edge of the disc cap 1 to simplify the assembly of the brake assembly. Of course, in other embodiments, the mounting hole 11 may also be a hole closed on all four sides, and this disclosure does not limit this.

[0064] The elastic element 4 is disposed between the connecting assembly 3 and the disc cap 1. During braking, the elastic element 4 allows the brake disc 2 to elastically float relative to the disc cap 1 to prevent wear on the brake disc 2, thereby avoiding irreversible deterioration of the performance of the brake disc 2.

[0065] For example, in some braking scenarios, such as multiple continuous braking or extreme operating conditions, the radial direction of the brake disc 2 relative to the disc cap 1 may become misaligned. This can easily lead to uneven wear between the brake disc 2 and the disc cap 1, causing mechanical damage to the brake disc 2 or generating noise, affecting its performance and shortening its service life.

[0066] To address the aforementioned issues, please refer to Figure 4. The elastic element 4 includes at least one of steel, iron, aluminum alloy, and ceramic elastic elements. For example, the elastic element 4 can be a 316L stainless steel elastic element.

[0067] The elastic element 4 may include a radially floating portion 41, which is housed within the mounting hole 11, as shown in Figures 2 and 3. The radially floating portion 41 is disposed between the disc cap 1 and the connecting assembly 3 along the radial direction of the disc cap 1. For example, the radially floating portion 41 may be located on the side of the connecting assembly 3 facing the center of the disc cap 1. In some embodiments, the radially floating portion 41 may be disposed between the edge of the mounting hole 11 near the center of the disc cap 1 and the connecting assembly 3. This structure is simple and easy to implement. The radially floating portion 41 is elastically deformable along the radial direction of the disc cap 1.

[0068] In this way, during braking, the brake disc 2 has a radial floating margin relative to the disc cap 1, so as to avoid uneven wear between the brake disc 2 and the disc cap 1 after the brake disc 2 is radially misaligned relative to the disc cap 1, thereby reducing the mechanical damage to the brake disc 2, avoiding noise, and extending the service life of the brake disc 2.

[0069] In the above embodiment, the elastic deformation of the radial floating part 41 along the radial direction of the disc cap 1 can be greater than or equal to 0.05 mm and less than or equal to 0.9 mm. For example, the elastic deformation of the radial floating part 41 along the radial direction of the disc cap 1 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm. In this way, the radial floating amount requirement can be met, while ensuring structural compactness.

[0070] The radial floating part 41 can be made of various materials and have various shapes. For example, the material of the radial floating part 41 can be spring steel, or elastic rubber or silicone. The shape of the radial floating part 41 includes, but is not limited to, serpentine, S-shaped, n-shaped, etc.

[0071] The radial floating portion 41 may include at least one elastic portion, any one of which is elastically deformable along the radial direction of the disc cap 1. The elastic portion may be a helical spring, disc spring, leaf spring, etc. In some embodiments, the elastic portion is elastically deformable along the radial direction of the disc cap 1 in a direction away from the center of the disc cap 1, or the elastic portion is elastically deformable along the radial direction of the disc cap 1 in a direction closer to the center of the disc cap 1.

[0072] In some embodiments, the elastic portion may include a curved section that arches toward the center of the cap 1, so that the elastic portion can elastically deform in the radial direction away from the center of the cap 1. Alternatively, the curved section arches away from the center of the cap 1, so that the elastic portion can elastically deform in the radial direction closer to the center of the cap 1. This structure is simple and easy to implement.

[0073] In some embodiments, referring to Figures 2 to 4, the radial floating portion 41 includes at least one first elastic portion 411 and at least one second elastic portion 412 arranged alternately in sequence along the circumference of the cap 1. Each of the at least one first elastic portion 411 includes a first curved section that arches towards the center of the cap 1. Each of the at least one second elastic portion 412 includes a second curved section that arches away from the center of the cap 1.

[0074] This structure is simple, and through the shape design of the radial floating part 41, the radial floating part 41 has elasticity along the radial direction of the cap 1, and the stability of the elastic force is better.

[0075] In some embodiments, referring to Figures 2 to 4, at least one first elastic portion 411 includes two first elastic portions 411, and at least one second elastic portion 412 includes one second elastic portion 412. Along the circumferential direction of the cap 1, the one second elastic portion 412 is located between the two first elastic portions 411.

[0076] The radial floating portion 41 of this shape has a simple structure and is easy to manufacture. Of course, the first elastic portion 411 and the second elastic portion 412 can also be of other quantities, and this disclosure does not limit this.

[0077] The first and second curved segments can have arc-shaped, crest-shaped, Λ-shaped, Ω-shaped, П-shaped, or irregular shapes in the first cross-section. Here, the first cross-section is perpendicular to the axis of the cap 1. The embodiment shown in Figure 4 is illustrated by using a crest-shaped first and second curved segments in the first cross-section as an example.

[0078] In other embodiments, please refer to FIG5, the second curved segment has an Ω-shaped shape in the first cross section, and the first curved segment has an irregular shape in the first cross section.

[0079] In some embodiments, referring to Figures 4 and 5, the elastic member 4 may further include two connecting portions 42. These two connecting portions 42 are arranged circumferentially at intervals along the cap 1, and a radial floating portion 41 connects the two connecting portions 42 between their ends facing the center of the cap 1. Each of the two connecting portions 42 has at least one axially floating portion 43, which is slightly bent and disposed between the cap 1 and the connecting assembly 3, and is elastically deformable along the axial direction of the cap 1. For example, the axially floating portion 43 may be disposed between the cap 1 and the first stop portion 322, or between the cap 1 and the second stop portion 323.

[0080] In this way, during braking, the axial floating part 43 can make the brake disc 2 have an axial floating margin relative to the disc cap 1, so as to avoid wear between the brake disc 2 and the disc cap 1 after the brake disc 2 moves axially relative to the disc cap 1, thereby reducing the mechanical damage to the brake disc 2 and extending the service life of the brake disc 2.

[0081] In some embodiments, referring to Figures 4 or 5, at least one axial floating portion 43 includes two axial floating portions 43, which are respectively connected to the two ends of the connecting portion 42 in the axial direction of the disc cap 1. The two axial floating portions 43 increase the axial floating elastic force of the brake disc 2 relative to the disc cap 1, ensuring structural strength. Simultaneously, the two axial floating portions 43 and the connecting portion 42 form a U-shaped structure, which cooperates with the disc cap 1 to limit the offset of the elastic element 4 relative to the disc cap 1.

[0082] In some embodiments, the thickness of either of the two axially floating portions 43 can be greater than or equal to 0.4 mm and less than or equal to 0.8 mm. For example, the thickness of the axially floating portion 43 can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm. In this way, the thickness of the axially floating portion 43 is moderate, which can simultaneously take into account structural strength and elasticity.

[0083] In some embodiments, referring to Figures 2 through 4, the end of the connecting portion 42 facing the center of the cap 1 is designated as the first end D1, and the end of the connecting portion 42 facing away from the center is designated as the second end D2. Along the radial direction of the cap 1, the shortest distance between the second curved segment and the plane containing the second end D2 is designated as the first distance w1, and the maximum distance between the first curved segment and the plane containing the first end D1 is designated as the second distance w2. The ratio of the first distance w1 to the second distance w2 (i.e., w1:w2) is greater than or equal to 3.72 and less than or equal to 22.54; for example, this ratio can be 4.17 or 4.5. This results in the elastic element 4 having good strength and stiffness.

[0084] In some embodiments, referring to FIG5, one of the two connecting portions 42 has a first limiting portion 44 on the surface of the other connecting portion 42 facing away from the other. The first limiting portion 44 is configured to cooperate with the disc cap 1 to prevent the elastic member 4 from separating from the disc cap 1 radially. In this way, as the brake disc 202 rotates with the wheel hub 201, the elastic member 4 is prevented from separating from the disc cap 1 radially under the action of centrifugal force, thus ensuring structural stability.

[0085] In the above embodiments, the first limiting part 44 includes, but is not limited to, a limiting protrusion or a limiting groove. Some embodiments of this disclosure are mainly illustrated by using the first limiting part 44 as a limiting protrusion. Based on this, the inner sidewall of the mounting hole 11 on the disc cap 1 is provided with a limiting groove. The elastic member 4, by means of the limiting protrusion and the limiting groove, can prevent the elastic member 4 from separating from the disc cap 1 radially.

[0086] In some embodiments, referring to FIG5, the protrusion height of the first limiting portion 44 relative to the connecting portion 42 is a first height h, and the length of the connecting portion 42 along the circumference of the cap 1 is a first length a. The ratio of the first height h to the first length a is greater than or equal to 1 / 6 and less than or equal to 1 / 3. In this way, the limiting stability of the first limiting portion 44 is better, and it is also convenient for the elastic element to be inserted into the mounting hole 11.

[0087] Similarly, please refer to Figure 6 and Figure 3. In each of the two axially floating portions 43 located in each connecting portion 42, a second limiting portion 45 is provided on the surface of one axially floating portion 43 facing the other. The second limiting portion 45 is configured to cooperate with the disc cap 1 to prevent the elastic element 4 from separating from the disc cap 1 radially. In this way, as the brake disc 202 rotates with the wheel hub 201, the elastic element 4 is also prevented from separating from the disc cap 1 radially under the action of centrifugal force, ensuring structural stability.

[0088] In the above embodiments, the second limiting portion 45 includes, but is not limited to, a limiting protrusion or a limiting groove. Some embodiments of this disclosure are mainly illustrated by using the second limiting portion 45 as a limiting protrusion. Based on this, the disc cap 1 is provided with a limiting groove. The elastic member 4, by means of the limiting protrusion and the limiting groove, can prevent the elastic member 4 from separating from the disc cap 1 radially.

[0089] In some embodiments, the protrusion height of the second limiting portion 45 is a second height, and the distance between the two axial floating portions 43 disposed on each connecting portion 42 is a third distance. The third height is greater than or equal to 1 / 6 and less than or equal to 1 / 3 of the value of the third distance. In this way, the limiting stability of the second limiting portion 45 is better, and it is also convenient for the elastic member 4 to be assembled with the disc cap 1.

[0090] In some embodiments, referring to FIG2, the brake disc 202 further includes an auxiliary elastic member 5, which is connected between the connecting assembly 3 and the disc cap 1. For example, a portion of the auxiliary elastic member 5 is sleeved on the connecting member and clamped between the connecting member limiting sleeve 32 and the nut 33, while another portion of the auxiliary elastic member 5 is fixed to the disc cap 1. By means of the elastic arm between this portion and the other portion of the auxiliary elastic member 5, the elastic floating force of the brake disc 2 relative to the disc cap 1 along the axial direction of the disc cap 1 can be increased, ensuring structural strength.

[0091] As an important automotive component, the performance of brake discs directly affects the braking effect and driving safety of a vehicle.

[0092] Aluminum-ceramic brake discs are a new type of brake disc material that combines the advantages of aluminum and ceramic. Compared to traditional cast iron brake discs, aluminum-ceramic brake discs are lighter, helping to reduce the overall weight of the vehicle and improve fuel economy and acceleration performance. This material has excellent thermal conductivity, effectively dissipating heat generated during braking, preventing brake fade, and improving the stability of the braking system. Aluminum-ceramic brake discs have high hardness, effectively resisting wear and extending the life of the brake disc. Ultimately, this significantly improves the performance of the automotive braking system.

[0093] Currently, aluminum-ceramic brake discs mainly consist of a friction layer and a structural layer. The structural layer typically uses aluminum alloy or aluminum alloy reinforced with low volume fraction ceramic particles, while the friction layer primarily uses aluminum alloy reinforced with high volume fraction ceramic particles. In related technologies, to meet the wear resistance requirements of the friction layer, its ceramic particle content can reach over 75%, or even be a pure ceramic layer. During the brake disc manufacturing process, if there is a significant difference between the thermal expansion coefficients of the structural layer and the friction layer, thermal mismatch may occur between the two layers, leading to cracking of the friction layer or thermal fatigue during braking, resulting in serious problems such as brake failure.

[0094] To address the aforementioned problems, some embodiments of this disclosure provide a brake disc, including a structural layer and a friction layer disposed on at least one side of the structural layer. The structural layer and the friction layer satisfy: -2Hα m ≤Δα≤2Hα m .

[0095] Where, Δα=α m -α f α m α represents the coefficient of thermal expansion of the structural layer. f H represents the coefficient of thermal expansion of the friction layer; H = H2 / H1, where H1 represents the thickness of the structural layer and H2 represents the thickness of the friction layer.

[0096] In other words, the difference between the thermal expansion coefficients of the structural layer and the friction layer is related to the thicknesses of the structural and friction layers, as well as the thermal expansion coefficient of the structural layer. A larger ratio between the thicknesses of the friction layer (H2) and the structural layer (H1) allows for a larger difference (Δα) in their thermal expansion coefficients. Conversely, a smaller ratio between the thicknesses of the friction layer (H2) and the structural layer (H1) allows for a smaller difference (Δα) in their thermal expansion coefficients.

[0097] Some embodiments of this disclosure, by comprehensively considering the thickness of the structural layer and the friction layer as well as the coefficient of thermal expansion, can control the thermal mismatch between the structural layer and the friction layer within a suitable range, reduce the thermal mismatch between the two, improve the bonding tightness between the structural layer and the friction layer, reduce the residual stress generated at the bonding interface between the structural layer and the friction layer during braking, and ensure the structural stability of the brake disc.

[0098] In some embodiments, 0.025 ≤ H2 / H1 ≤ 0.25. Setting the thicknesses of the structural layer and the friction layer within a suitable ratio range helps improve brake disc performance. Specifically, by controlling H2 / H1 within the aforementioned range, it is possible to ensure a smaller thermal mismatch between the structural layer and the friction layer, improve the bonding strength between them, reduce brake disc fade, and provide better support for the friction layer with a thicker structural layer, while a thinner friction layer allows for brake disc weight reduction while maintaining friction performance.

[0099] It should be noted that when the thickness difference between the structural layer and the friction layer is significant, the brake disc is prone to internal stress due to the difference in thermal expansion under temperature changes. This can easily lead to problems such as deformation and cracking of the brake disc. Therefore, when the thickness difference between the structural layer and the friction layer is large—that is, when the ratio between the thickness H2 of the friction layer and the thickness H1 of the structural layer is small—the difference in the coefficients of thermal expansion between the structural layer and the friction layer should be kept within a small range to compensate for the internal stress caused by the excessive thickness difference and ensure the stability of the brake disc.

[0100] Conversely, when the thickness difference between the structural layer and the friction layer is small, the internal stress generated between the structural layer and the friction layer is small when the brake disc changes temperature. This can reduce problems such as deformation and cracking of the brake disc, and thus allow the thermal expansion coefficients of the structural layer and the friction layer to have a larger fluctuation range.

[0101] In some embodiments, the structural layer comprises aluminum alloy and a first ceramic material, wherein the volume percentage of the first ceramic material in the structural layer is V1, where 0 < V1 ≤ 50%. Using aluminum alloy enables the structural layer to be lightweight, while including the first ceramic material in the structural layer helps improve its high-temperature performance and heat dissipation. By controlling the volume percentage of the first ceramic material in the structural layer to below 50%, the toughness, thermal stability, and structural strength of the structural layer can be guaranteed.

[0102] In some embodiments, the raw material of the friction layer includes a second ceramic material, wherein the volume percentage of the second ceramic material in the friction layer is V2, and 40% ≤ V2 ≤ 100%. The inclusion of a second ceramic material in the friction layer, and the fact that the second ceramic material accounts for more than 40% of the friction layer, enables the friction layer to have better high-temperature resistance and friction performance, maintains the stability of the brake disc during braking, and improves braking effect.

[0103] In some embodiments, the friction layer further includes aluminum alloy material and a third ceramic material, wherein the volume percentage of the third ceramic material in the friction layer is V3, and 40% ≤ V2 + V3 ≤ 100%. Adding aluminum alloy material to the friction layer improves thermal conductivity and wear resistance, contributing to the lightweighting of the brake disc. The friction layer also includes a third ceramic material, which can adjust the coefficient of thermal expansion, hardness, coefficient of friction, and toughness of the friction layer.

[0104] In some embodiments, the first ceramic material includes silicon carbide, the second ceramic material includes silicon carbide, and the coefficient of thermal expansion of the third ceramic material is greater than that of the second ceramic material. Silicon carbide has extremely high high-temperature resistance, maintaining stable physical and chemical properties at high temperatures. It also possesses high strength and hardness; therefore, its application in structural layers can improve structural stability and enhance the supporting performance of the structural layers. When applied to friction layers, silicon carbide can improve the coefficient of friction and wear resistance of the friction layers, and reduce the risk of thermal degradation.

[0105] The coefficient of thermal expansion of the third ceramic material is greater than that of the second ceramic layer material. Incorporating the third ceramic material into the friction layer can reduce the difference in thermal expansion coefficients between the friction layer and the structural layer, while ensuring the friction layer has a good coefficient of friction and good wear resistance. This reduces thermal mismatch between the two layers and improves their bonding strength.

[0106] In some embodiments, the coefficient of thermal expansion of the second ceramic material is C1, and the coefficient of thermal expansion of the third ceramic material is C2, where 2.3 × 10⁻⁶ is the coefficient of thermal expansion. -6 / ℃≤C2-C1≤10×10 -6 / ℃. By controlling the coefficients of thermal expansion of the second and third ceramic materials to 2.3×10⁻⁶, the thermal expansion coefficients of the two ceramic materials are controlled. -6 / ℃≤C2-C1≤10×10 -6 / ℃, which allows the third ceramic material to better adjust the thermal expansion coefficient of the friction layer, reduce the difference in thermal expansion coefficients between the friction layer and the structural layer, and reduce the risk of thermal mismatch caused by excessive differences in thermal expansion coefficients between different materials in the friction layer.

[0107] In some embodiments, the structural layer and the friction layer satisfy Formula 1:

[0108] Where a represents the thermal expansion coefficient of the third ceramic material, V1 represents the volume ratio of the first ceramic material in the structural layer, V2 represents the volume ratio of the second ceramic material in the friction layer, V3 represents the volume ratio of the third ceramic material in the friction layer, H = H2 / H1, H1 represents the thickness of the structural layer, and H2 represents the thickness of the friction layer.

[0109] By ensuring that the structural layer and the friction layer satisfy Formula 1, the thermal mismatch between the structural layer and the friction layer can be minimized, thereby improving the tightness of the bond between the structural layer and the friction layer and reducing the occurrence of problems such as cracking and damage of the brake disc during braking.

[0110] In some embodiments, the thickness H1 of the structural layer satisfies: 15mm ≤ H1 ≤ 60mm. When the thickness of the structural layer is within this range, the structural layer can provide sufficient strength and braking stability to ensure braking performance.

[0111] For example, the thickness of the structural layer can be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm or 60mm.

[0112] In some embodiments, the thickness of the structural layer can be in the range of [20mm, 40mm]. By controlling the thickness of the structural layer within the range of [20mm, 40mm], it is possible to ensure that the structural layer can withstand greater stress while reducing its own weight.

[0113] In some embodiments, the thickness H2 of the friction layer satisfies: 0.5mm ≤ H2 ≤ 15mm. Controlling the thickness of the friction layer within this range provides sufficient friction and helps to achieve uniform wear.

[0114] For example, the thickness of the friction layer can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or 15mm.

[0115] In some embodiments, the thickness of the friction layer can be in the range of [2 mm, 10 mm]. By controlling the thickness of the friction layer within the range of [2 mm, 10 mm], both its friction performance and good strength can be guaranteed.

[0116] In some embodiments, the aluminum alloy material includes at least one of binary aluminum alloy and hexagonal aluminum alloy. Using at least one of binary and hexagonal aluminum alloys can help form at least one of a denser structural layer and friction layer during the brake disc manufacturing process.

[0117] Here, bi-series aluminum alloys are aluminum alloys with copper as the main alloying element, typically including aluminum-copper-magnesium alloys, aluminum-copper-manganese alloys, and aluminum-copper-magnesium-iron-nickel alloys, such as 2024 aluminum alloy, 2A16 (LY16) aluminum alloy, and 2A02 (LY2) aluminum alloy. Sixth-series aluminum alloys are aluminum alloys with magnesium and silicon as the main alloying elements, and Mg2Si as the main strengthening phase, such as 6061 aluminum alloy and 6063 aluminum alloy.

[0118] In some embodiments, the particle size range of the aluminum alloy material is [5 μm, 20 μm]. Using aluminum alloy materials with smaller particle sizes, i.e., refining the grains, can improve the strength of the material itself, thereby increasing the structural strength of the brake disc. Furthermore, aluminum alloy materials within this particle size range can also improve wear resistance and increase heat transfer efficiency.

[0119] In some embodiments, the third ceramic material includes at least one of alumina, zirconium oxide, titanium carbide, and tungsten carbide. Alumina, zirconium oxide, titanium carbide, and tungsten carbide have higher coefficients of thermal expansion than silicon carbide. Doping the friction layer with at least one of these materials can reduce the difference in coefficients of thermal expansion between the friction layer and the structural layer while ensuring the friction performance of the friction layer. This helps to reduce the thermal mismatch between the friction layer and the structural layer and ensures the bonding strength between them.

[0120] In some embodiments, the particle size range of the first ceramic material is [50 μm, 300 μm]. When the first ceramic material is controlled within this range, a stable coefficient of friction can be ensured, thermal fading problems can be reduced, and wear during braking can be better resisted, thereby extending the service life of the structural layer.

[0121] In some embodiments, the particle size range of the second ceramic material is [50 μm, 300 μm]. Similar to the first ceramic material, when the second ceramic material is controlled within this range, a stable coefficient of friction can be ensured, thermal fading problems can be reduced, and wear during braking can be better resisted, thereby extending the service life of the friction layer.

[0122] In some embodiments, the particle size range of the third ceramic material is [50 μm, 300 μm]. Similar to the first and second ceramic materials, when the third ceramic material is controlled within this range, a stable coefficient of friction can be ensured, thermal fading problems can be reduced, and wear during braking can be better resisted, thereby extending the service life of the friction layer.

[0123] In some embodiments, the friction layer includes a first friction layer and a second friction layer, which are respectively disposed on opposite sides of the structural layer. Here, the thickness of the friction layer is the total thickness of the first friction layer and the second friction layer.

[0124] By setting a first friction layer and a second friction layer on opposite sides of the structural layer, bi-directional braking can be achieved, thereby improving braking efficiency. Furthermore, bi-directional braking also helps maintain a balance of braking force, improving braking stability. In addition, setting a first friction layer and a second friction layer on opposite sides of the structural layer also helps ensure uniform friction and improve heat dissipation.

[0125] In some embodiments, the coefficient of friction of the brake disc is in the range of [0.35, 0.45]. Controlling the coefficient of friction of the brake disc within the range of [0.35, 0.45] can achieve a stable braking effect and reduce the occurrence of lock-up during braking.

[0126] In some embodiments, the wear rate of the brake disc is <1 μm / face × cycle. By keeping the thermal mismatch between the structural layer and the friction layer within a certain range, the bonding tightness between the structural layer and the friction layer can be improved, resulting in a lower wear rate of the friction layer during use, thereby extending the service life of the brake disc.

[0127] Here, μm / face × times represents the thickness of each face of the brake disc that is worn away in a single wear test.

[0128] This disclosure also provides a method for manufacturing a brake disc, which includes:

[0129] Provide raw materials for the structural layer and the friction layer;

[0130] The raw materials for the structural layer and the friction layer are laid in a mold and pressed to obtain a green body.

[0131] The green blank is sintered and hot-pressed to obtain the brake disc.

[0132] In some embodiments, the raw materials for the structural layer and the friction layer are provided, including:

[0133] The raw materials for the structural layer and the friction layer are prepared separately according to the specified proportions. For example, aluminum alloy material and first ceramic material are compounded according to the specified proportions to obtain the raw materials for the structural layer, and aluminum alloy material, third ceramic material and second ceramic material are compounded according to the specified proportions to obtain the raw materials for the friction layer.

[0134] In some embodiments, before laying the raw materials for the structural layer and the friction layer in the mold, the method further includes:

[0135] The raw materials for the structural layer and the friction layer were ball-milled separately.

[0136] After ball milling the raw materials for the structural layer and the friction layer respectively, the raw materials can be refined and crushed, and the different components in the raw materials can be mixed evenly. The ball milling process can also modify the surface of the raw materials, making the surface of the raw materials smoother and more uniform.

[0137] In some embodiments, the raw materials for the structural layer and the friction layer are ball-milled using cemented carbide under an inert atmosphere. Here, the ball-to-material ratio is set to a range of [3:1, 10:1], and the ball-milling time is any duration of [4h, 6h].

[0138] In some embodiments, the raw materials for the structural layer and the friction layer are laid in a mold and pressed, including:

[0139] The raw materials for the structural layer and the friction layer are laid in the mold;

[0140] At room temperature, pressurize using any pressure value within the pressure range of [200MPa, 500MPa], and hold for any duration of [1min, 5min].

[0141] Pressing at room temperature allows the structural and friction layers to be initially formed, creating a green body that facilitates subsequent operations. Pressing at any pressure value within the range of [200MPa, 500MPa] and holding the pressure for any duration of [1min, 5min] densifies the raw material and fixes it into the desired shape in the mold, ensuring that the particles in the raw material are fully combined to obtain a structurally stable green body.

[0142] In some embodiments, sintering and hot pressing of the green compact includes:

[0143] In an inert gas environment, the green body is sintered for any duration of [3h, 5h] at a temperature of [560℃, 620℃], then hot-pressed at any temperature of [500℃, 550℃] and any pressure of [100MPa, 300MPa], held at pressure for any duration of [10s, 30s], and then cooled to room temperature.

[0144] Sintering in an inert atmosphere reduces the reaction between the raw materials and the external environment. Setting the sintering temperature range to [560℃, 620℃] and the sintering time range to [3h, 5h] allows the raw materials in the structural layer and friction layer to bond together through surface diffusion, volume diffusion, and grain boundary migration, forming a dense whole. After sintering, hot pressing at a temperature range of [500℃, 550℃] further densifies the structural layer and friction layer, improving density and mechanical properties.

[0145] Here, a temperature range of [500℃, 550℃] facilitates plastic deformation of the raw materials in the structural and friction layers, while a pressure range of [100MPa, 300MPa] ensures closer contact between the raw material particles, promoting particle bonding. Through the combined effect of temperature and pressure, density and mechanical properties are significantly improved. Under higher temperature and pressure conditions, plastic deformation and densification processes occur rapidly, therefore, maintaining any duration within [10s, 30s] is sufficient.

[0146] Some embodiments of this disclosure also provide a brake, including at least one of the brake discs described above and brake discs manufactured by the methods described above. This brake has all the beneficial effects of the described brake discs, which will not be elaborated further herein.

[0147] Some embodiments of this disclosure also provide a vehicle including the brakes described above. This vehicle possesses all the beneficial effects of the described brake discs, which will not be elaborated further herein.

[0148] The brake discs provided in some embodiments of this disclosure will be described below with reference to specific examples.

[0149] It should be noted that, unless otherwise specified, the percentages in the embodiments and comparative examples are all volume percentages.

[0150] Example 1

[0151] In this embodiment, the raw materials for the structural layer include 70% 6061 aluminum alloy powder and 30% silicon carbide powder. The raw materials for the friction layer include 30% 6061 aluminum alloy powder, 55% silicon carbide powder, and 15% alumina powder.

[0152] (1) Prepare the raw materials for the structural layer and the friction layer according to the proportions;

[0153] (2) Under the condition of ball-to-material ratio of 5:1, the raw materials of the structural layer and the friction layer were ball-milled with cemented carbide for 5 hours respectively;

[0154] (3) The above raw materials are laid in the mold according to the three-layer structure of the first friction layer, the structural layer and the second friction layer. Here, the thickness of the structural layer is 30mm and the total thickness of the first friction layer and the second friction layer is 6mm.

[0155] (4) Place the mold after laying the raw materials on the hydraulic press platform, hold the pressure at 300MPa for 3 minutes, and press to obtain the green blank;

[0156] (5) Transfer the mold and the green blank together to an inert atmosphere sintering furnace, sinter at 600°C for 3 hours, cool to 500°C, transfer to a hot press under an argon atmosphere, hold pressure at 500°C and 150MPa for 30 seconds, and then cool to room temperature under an argon atmosphere to obtain a brake disc blank.

[0157] (6) Take out the brake disc blank and perform machining, dimensional processing and surface polishing to obtain the brake disc.

[0158] Example 2

[0159] In this embodiment, the raw materials for the structural layer include 70% 6061 aluminum alloy powder and 30% silicon carbide powder. The raw materials for the friction layer include 40% 6061 aluminum alloy powder, 30% silicon carbide powder, and 30% alumina powder.

[0160] (1) Prepare the raw materials for the structural layer and the friction layer according to the proportions;

[0161] (2) Under the condition of ball-to-material ratio of 5:1, the raw materials of the structural layer and the friction layer were ball-milled with cemented carbide for 5 hours respectively;

[0162] (3) The above raw materials are laid in the mold according to the three-layer structure of the first friction layer, the structural layer and the second friction layer. Here, the thickness of the structural layer is 30mm and the total thickness of the first friction layer and the second friction layer is 6mm.

[0163] (4) Place the mold after laying the raw materials on the hydraulic press platform, hold the pressure at 300MPa for 3 minutes, and press to obtain the green blank;

[0164] (5) Transfer the mold and the green blank together to an inert atmosphere sintering furnace, sinter at 600°C for 3 hours, cool to 500°C, transfer to a hot press under an argon atmosphere, hold pressure at 500°C and 150MPa for 30 seconds, and then cool to room temperature under an argon atmosphere to obtain a brake disc blank.

[0165] (6) Take out the brake disc blank and perform machining, dimensional processing and surface polishing to obtain the brake disc.

[0166] Example 3

[0167] In this embodiment, the raw materials for the structural layer include 70% 6061 aluminum alloy powder and 30% silicon carbide powder. The raw materials for the friction layer include 40% 6061 aluminum alloy powder, 30% silicon carbide powder, and 30% zirconium oxide powder.

[0168] (1) Prepare the raw materials for the structural layer and the friction layer according to the proportions;

[0169] (2) Under the condition of ball-to-material ratio of 5:1, the raw materials of the structural layer and the friction layer were ball-milled with cemented carbide for 5 hours respectively;

[0170] (3) The above raw materials are laid in the mold according to the three-layer structure of the first friction layer, the structural layer and the second friction layer. Here, the thickness of the structural layer is 30mm and the total thickness of the first friction layer and the second friction layer is 6mm.

[0171] (4) Place the mold after laying the raw materials on the hydraulic press platform, hold the pressure at 300MPa for 3 minutes, and press to obtain the green blank;

[0172] (5) Transfer the mold and the green blank together to an inert atmosphere sintering furnace, sinter at 600°C for 3 hours, cool to 500°C, transfer to a hot press under an argon atmosphere, hold pressure at 500°C and 150MPa for 30 seconds, and then cool to room temperature under an argon atmosphere to obtain a brake disc blank.

[0173] (6) Take out the brake disc blank and perform machining, dimensional processing and surface polishing to obtain the brake disc.

[0174] Example 4

[0175] In this embodiment, the structural layer is made of 100% 6061 aluminum alloy powder. The friction layer is made of 50% 6061 aluminum alloy powder, 10% silicon carbide powder, and 40% zirconium oxide powder.

[0176] (1) Prepare the raw materials for the structural layer and the friction layer according to the proportions;

[0177] (2) Under the condition of ball-to-material ratio of 5:1, the raw materials of the structural layer and the friction layer were ball-milled with cemented carbide for 5 hours respectively;

[0178] (3) The above raw materials are laid in the mold according to the three-layer structure of the first friction layer, the structural layer and the second friction layer. Here, the thickness of the structural layer is 30mm and the total thickness of the first friction layer and the second friction layer is 6mm.

[0179] (4) Place the mold after laying the raw materials on the hydraulic press platform, hold the pressure at 300MPa for 3 minutes, and press to obtain the green blank;

[0180] (5) Transfer the mold and the green blank together to an inert atmosphere sintering furnace, sinter at 600°C for 3 hours, cool to 500°C, transfer to a hot press under an argon atmosphere, hold pressure at 500°C and 150MPa for 30 seconds, and then cool to room temperature under an argon atmosphere to obtain a brake disc blank.

[0181] (6) Take out the brake disc blank and perform machining, dimensional processing and surface polishing to obtain the brake disc.

[0182] Example 5

[0183] In this embodiment, the structural layer comprises 70% 2024 aluminum alloy powder and 30% silicon carbide powder. The friction layer comprises 40% 2024 aluminum alloy powder, 30% silicon carbide powder, and 30% zirconium oxide powder.

[0184] (1) Prepare the raw materials for the structural layer and the friction layer according to the proportions;

[0185] (2) Under the condition of ball-to-material ratio of 5:1, the raw materials of the structural layer and the friction layer were ball-milled with cemented carbide for 5 hours respectively;

[0186] (3) The above raw materials are laid in the mold according to the three-layer structure of the first friction layer, the structural layer and the second friction layer. Here, the thickness of the structural layer is 30mm and the total thickness of the first friction layer and the second friction layer is 6mm.

[0187] (4) Place the mold after laying the raw materials on the hydraulic press platform, hold the pressure at 300MPa for 3 minutes, and press to obtain the green blank;

[0188] (5) Transfer the mold and the green blank together to an inert atmosphere sintering furnace, sinter at 600°C for 3 hours, cool to 500°C, transfer to a hot press under an argon atmosphere, hold pressure at 500°C and 150MPa for 30 seconds, and then cool to room temperature under an argon atmosphere to obtain a brake disc blank.

[0189] (6) Take out the brake disc blank and perform machining, dimensional processing and surface polishing to obtain the brake disc.

[0190] Example 6

[0191] In this embodiment, the structural layer comprises 70% 6061 aluminum alloy powder and 30% silicon carbide powder. The friction layer comprises 40% 6061 aluminum alloy powder, 30% silicon carbide powder, and 30% zirconium oxide powder.

[0192] (1) Prepare the raw materials for the structural layer and the friction layer according to the proportions;

[0193] (2) Under the condition of ball-to-material ratio of 5:1, the raw materials of the structural layer and the friction layer were ball-milled with cemented carbide for 5 hours respectively;

[0194] (3) The above raw materials are laid in the mold according to the three-layer structure of the first friction layer, the structural layer and the second friction layer. Here, the thickness of the structural layer is 30mm and the total thickness of the first friction layer and the second friction layer is 6mm.

[0195] (4) Place the mold after laying the raw materials on the hydraulic press platform, hold the pressure at 300MPa for 3 minutes, and press to obtain the green blank;

[0196] (5) Transfer the mold and the green blank together to an inert atmosphere sintering furnace, sinter at 600°C for 3 hours, cool to 500°C, transfer to a hot press under an argon atmosphere, hold pressure at 500°C and 150MPa for 30 seconds, and then cool to room temperature under an argon atmosphere to obtain a brake disc blank.

[0197] (6) Take out the brake disc blank and perform machining, dimensional processing and surface polishing to obtain the brake disc.

[0198] Comparative Example 1

[0199] In this comparative example, the structural layer consists of 50% 6061 aluminum alloy powder and 50% silicon carbide powder. The friction layer consists of 20% 6061 aluminum alloy powder and 80% silicon carbide powder.

[0200] (1) Prepare the raw materials for the structural layer and the friction layer according to the proportions;

[0201] (2) Under the condition of ball-to-material ratio of 5:1, the raw materials of the structural layer and the friction layer were ball-milled with cemented carbide for 5 hours respectively;

[0202] (3) The above raw materials are laid in the mold according to the three-layer structure of the first friction layer, the structural layer and the second friction layer. Here, the thickness of the structural layer is 30mm and the total thickness of the first friction layer and the second friction layer is 5mm.

[0203] (4) Place the mold after laying the raw materials on the hydraulic press platform, hold the pressure at 300MPa for 3 minutes, and press to obtain the green blank;

[0204] (5) Transfer the mold and the green blank together to an inert atmosphere sintering furnace, sinter at 600°C for 3 hours, cool to 500°C, transfer to a hot press under an argon atmosphere, hold pressure at 500°C and 150MPa for 30 seconds, and then cool to room temperature under an argon atmosphere to obtain a brake disc blank.

[0205] (6) Take out the brake disc blank and perform machining, dimensional processing and surface polishing to obtain the brake disc.

[0206] Comparative Example 2

[0207] In this comparative example, the structural layer consists of 70% 6061 aluminum alloy powder and 30% silicon carbide powder. The friction layer consists of 20% 6061 aluminum alloy powder, 70% silicon carbide powder, and 10% zirconium oxide powder.

[0208] (1) Prepare the raw materials for the structural layer and the friction layer according to the proportions;

[0209] (2) Under the condition of ball-to-material ratio of 5:1, the raw materials of the structural layer and the friction layer were ball-milled with cemented carbide for 5 hours respectively;

[0210] (3) The above raw materials are laid in the mold according to the three-layer structure of the first friction layer, the structural layer and the second friction layer. Here, the thickness of the structural layer is 30mm and the total thickness of the first friction layer and the second friction layer is 3mm.

[0211] (4) Place the mold after laying the raw materials on the hydraulic press platform, hold the pressure at 300MPa for 3 minutes, and press to obtain the green blank;

[0212] (5) Transfer the mold and the green blank together to an inert atmosphere sintering furnace, sinter at 600°C for 3 hours, cool to 500°C, transfer to a hot press under an argon atmosphere, hold pressure at 500°C and 150MPa for 30 seconds, and then cool to room temperature under an argon atmosphere to obtain a brake disc blank.

[0213] (6) Take out the brake disc blank and perform machining, dimensional processing and surface polishing to obtain the brake disc.

[0214] The bond strength between the structural layer and the friction layer in the brake discs of Examples 1-6 and Comparative Examples 1-2, as well as the coefficient of friction and wear rate of the brake discs, were tested. Here, the bond strength between the structural layer and the friction layer was tested according to the test method in GB / T5210-2006. The coefficient of friction and wear rate of the brake discs were tested according to the test method in T / CAAMTB90-2002. The results are shown in Table 1:

[0215] Table 1. Comparison of test results for different embodiments and comparative examples.

[0216] In Table 1, α m α represents the coefficient of thermal expansion of the structural layer. f The coefficient of thermal expansion of the friction layer is represented by Δα = α m -α f The thermal mismatch is:

[0217] As shown in Table 1, in the brake discs of Examples 1-6, the condition -2Hα is satisfied between both the structural layer and the friction layer. m ≤Δα≤2Hαm Under the given conditions, the bonding strength between the structural layer and the friction layer in the brake disc meets the requirements of T / CAAMTB90-2002 standard, and the friction coefficient and wear rate of the brake disc both meet the requirements of GB / T34422-2017 standard; no cracking issues were observed in the brake disc. However, Comparative Examples 1 and 2 did not meet the -2Hα requirement. m ≤Δα≤2Hα m The conditions were not met, and cracking issues existed. Furthermore, the bonding strength, friction coefficient, and wear rate were significantly lower than those of Examples 1-6, failing to meet the standard requirements.

[0218] Currently, the basic structure of aluminum-ceramic brake discs on the market typically includes a friction layer and an aluminum substrate. However, the friction coefficient of the aluminum-ceramic disc friction layer is lower than that of traditional cast iron discs when used at both room temperature and high temperatures. An excessively low friction coefficient can affect braking performance, significantly increase braking distance, and in severe cases, pose safety hazards.

[0219] To address the aforementioned issues, the structural layer (aluminum matrix) of aluminum-ceramic brake discs in related technologies is mostly made of aluminum alloy or aluminum-based composite material reinforced with low volume fraction ceramic particles, while the friction layer is an aluminum-based composite material reinforced with high volume fraction ceramic particles. To meet the wear resistance requirements of the friction layer, the ceramic particle content generally needs to reach 70% or higher. However, due to the still relatively high aluminum content and the low melting point of aluminum, the room temperature and high temperature friction coefficients of the aluminum-ceramic disc friction layer are currently lower than those of traditional cast iron discs. Continuing to increase the ceramic particle content to improve the wear resistance of the friction layer may lead to increased material brittleness, thereby reducing impact resistance and overall mechanical properties, ultimately affecting braking safety.

[0220] Based on this, some embodiments of this disclosure provide an aluminum-based composite with high wear resistance, which increases the wear resistance of the friction layer without reducing the mechanical properties of the aluminum-based composite material.

[0221] As shown in Figure 7, an aluminum-based composite material with a high coefficient of friction and wear resistance includes an aluminum substrate 1000 and a friction layer 2000. The friction layer 2000 is disposed on at least one side of the aluminum substrate 1000; that is, the friction layer 2000 can be disposed on one plane of the aluminum substrate 1000 or on two opposite planes of the aluminum substrate 1000. The friction layer 2000, as the side in contact with external forces, includes a first friction unit and a second friction unit, where the hardness of the second friction unit is greater than that of the first friction unit. By combining the second friction unit with the first friction unit to jointly constitute the friction layer 2000, the overall wear resistance of the friction layer 2000 is increased. The hardness difference between the first friction unit and the second friction unit can be set to [30HB, 500HB], specifically within the range [30HB, 200HB].

[0222] In some embodiments of this disclosure, the first friction unit comprises a ceramic reinforcing phase and aluminum, wherein the aluminum is distributed as a continuous phase in the first friction unit; that is, the first friction unit is composed of an aluminum-based composite material reinforced with ceramic particles, and the hardness of the first friction unit is controlled by controlling the proportion of the ceramic reinforcing phase in the aluminum-based composite material reinforced with ceramic particles.

[0223] In some embodiments of this disclosure, the ceramic reinforcement includes at least one of silicon carbide, alumina, tungsten carbide, zirconium oxide, titanium nitride, and silicon nitride, with the volume fraction of the ceramic reinforcement phase ranging from [50%, 80%], thereby controlling the hardness of the first friction unit within the range of [70HB, 200HB]. The hardness of the second friction unit ranges from [180HB, 1000HB]. In some embodiments, the hardness of the second friction unit ranges from [200HB, 800HB], and includes any material including hard ceramics, hard alloys, metal matrix composites, and cast iron.

[0224] In some embodiments, in the aluminum matrix composite, the composition of the aluminum matrix 1000 also includes aluminum, or includes a ceramic reinforcing phase and aluminum, with aluminum distributed as a continuous phase in the aluminum matrix; that is, the composition of the aluminum matrix 1000 is also an aluminum matrix composite material with or without ceramic particle reinforcement. The difference from the first friction unit is that in the aluminum matrix composite material with ceramic particle reinforcement constituting the aluminum matrix 1000, the volume fraction of the ceramic reinforcing phase ranges from [0%, 50%], which is less than the volume fraction of the ceramic reinforcing phase in the first friction unit; in some embodiments, the volume fraction of the ceramic reinforcing phase ranges from [10%, 50%]; in some embodiments, the volume fraction of the ceramic reinforcing phase ranges from... [20%, 40%]; and by selecting an appropriate preparation process, such as cold pressing and sintering, the aluminum matrix 1000 and the first friction unit are based on a continuous distribution of aluminum without a connecting interface; this effectively improves the integration of the aluminum matrix composite; and the low volume fraction range of the ceramic reinforcing phase in the aluminum matrix 1000 material (e.g., [0%, 50%]) allows the aluminum matrix 1000 to maintain the good thermal conductivity of aluminum, which is beneficial for quickly transferring the heat generated by the friction layer to the outside of the aluminum matrix composite through the aluminum matrix 1000, reducing the concentration of heat in the friction layer 2000 and reducing thermal decay.

[0225] In some embodiments, within the friction layer 2000, the area ratio of the first friction unit and the second friction unit is controlled within the range of [1:20, 6:4] to ensure the stability of the second friction unit in the aluminum matrix composite and the overall wear resistance of the friction layer 2000.

[0226] Referring again to Figure 7, given that the friction layer 2000 will experience wear during long-term use, and considering the differences in material and hardness between the first and second friction units, uneven wear between the first and second friction units will occur, affecting its service life. Therefore, in some embodiments of this disclosure, the second friction unit is configured to include multiple second sub-friction units 2002, and the first friction unit is configured to include multiple spaced-apart first sub-friction units 2001, with the multiple second sub-friction units and multiple first sub-friction units arranged alternately. In this way, a friction layer is formed on the surface of the aluminum substrate 1000, consisting of spaced-apart first sub-friction units 2001 and second sub-friction units 2002.

[0227] It is understood that a friction layer 2000, formed by a plurality of first sub-friction units 2001 and a plurality of second sub-friction units 2002, is provided on the upper and lower planes of the aluminum substrate 1000, or on any flat surface. The plurality of second sub-friction units 2002 have the same shape, and the spacing between any two adjacent second sub-friction units 2002 is equal. In some embodiments, the spacing between any two adjacent second sub-friction units is controlled within the range of [1mm, 100mm]; in some embodiments, the spacing between any two adjacent second sub-friction units is within the range of [5mm, 20mm]; the area ratio of a single first sub-friction unit 2001 to a single second sub-friction unit 2002 is within the range of [1:20, 6:4], thereby ensuring the uniformity of wear and tear on the friction layer under stress; in some embodiments, the shape of the second friction unit includes a fan shape, a square shape, or a circle.

[0228] In some embodiments, the second friction unit may include a plurality of second sub-friction units, wherein the orthographic projection of the first friction unit on the aluminum substrate surrounds the orthographic projection of the second sub-friction units on the aluminum substrate. That is, the first friction unit is an integral structure, and the plurality of second sub-friction units are uniformly embedded in the first friction unit. The spacing between any two adjacent second sub-friction units is maintained in the range of [1mm, 100mm]. In some embodiments, the spacing between any two adjacent second sub-friction units is in the range of [5mm, 20mm].

[0229] In some embodiments, the materials constituting the second friction unit include hard ceramics selected from at least one of silicon carbide, alumina, and tungsten carbide; cast iron selected from at least one of HT250 gray cast iron and HT350 gray cast iron; hard alloys including at least one of nickel-copper alloys and nickel-tungsten alloys; and metal matrix composites that can be iron-silicon carbide composites.

[0230] In some embodiments, the thickness of the aluminum substrate 1000 is controlled within the range of [20 mm, 50 mm]; the thickness of the friction layer is within the range of [2 mm, 15 mm].

[0231] In some embodiments of this disclosure, a brake disc comprising the above-mentioned aluminum-based composite material is provided to address the problem that the friction coefficient of the aluminum ceramic disc is low at room temperature and high temperature when using high volume fraction silicon carbide, and that the friction layer is prone to thermal mismatch with the aluminum matrix when using hard friction layers such as pure ceramic or cast iron, leading to the friction layer falling off. Since the friction layer of the aluminum-based composite material combines the performance advantages of reinforced aluminum-based composite material and hard ceramic or cast iron, the wear resistance is effectively improved.

[0232] In some embodiments of this disclosure, the aluminum-based composite described in the first aspect above is used as a brake disc. Referring to FIG9, here, the aluminum-based matrix 1000 serves as the structural layer of the brake disc, and the friction layer of the brake disc includes a first friction unit and a second friction unit. The aluminum-based matrix 1000 includes a ceramic reinforcing phase and aluminum, that is, the aluminum-based matrix 1000 is an aluminum-based composite material reinforced with ceramic particles. Aluminum is distributed as a continuous phase in the aluminum-based matrix 1000, and the volume fraction of the ceramic reinforcing phase ranges from [0%, 50%]; in some embodiments, the volume fraction of the ceramic reinforcing phase ranges from [10%, 50%]; in some embodiments, the volume fraction of the ceramic reinforcing phase ranges from [20%, 40%].

[0233] The first friction unit is an aluminum-based composite material reinforced with ceramic particles. Aluminum is distributed as a continuous phase in the first friction unit, and the volume fraction of the ceramic reinforcing phase ranges from 50% to 80%. Since both the aluminum matrix 1000 and the first friction unit are composed of aluminum-based composite materials reinforced with ceramic particles, by selecting appropriate preparation processes, such as cold pressing and sintering, the formed aluminum matrix 1000 and the first friction unit are based on a continuous distribution of aluminum, without any connecting interface. This effectively improves the integration of the aluminum-based composite. The aluminum matrix 1000 and the first friction unit have good material compatibility, which can avoid stress caused by excessive differences in their coefficients of thermal expansion, improve the thermal conductivity of the brake disc, increase heat dissipation efficiency, reduce heat fade, ensure continuous braking performance, and improve the stability and reliability of the brake disc.

[0234] In some embodiments, the first friction unit controls its hardness range to [70HB, 200HB] by adjusting the volume fraction of the ceramic reinforcing phase in the aluminum matrix composite material reinforced with ceramic particles to be in the range of [50%, 80%]. The second friction unit is made of a material with a wide hardness range (e.g., [180HB, 1000HB] compared to the first friction unit), including any material such as hard ceramics, hard alloys, metal matrix composites, and cast iron. It is more appropriate to keep the hardness difference between the first and second friction units within the range of [30HB, 500HB].

[0235] In some embodiments of this disclosure, the second friction unit selected in some embodiments meets the following performance requirements: the hardness HBW of the second friction unit is ≥180; the yield strength of the second friction unit is ≥160MPa; and the dry friction coefficient of the second friction unit relative to the braking material is in the range of [0.3, 0.5].

[0236] Compared to brake discs whose friction layer consists of a single first friction unit (an aluminum-based composite material reinforced with ceramic particles), although a higher volume fraction of ceramic reinforcing phase (e.g., [50%, 80%]) imparts stronger high-temperature resistance, the lower coefficient of friction negatively impacts braking performance and significantly increases braking distance. In some embodiments of this disclosure, a new friction layer is formed by combining the first friction unit with a second friction unit having a high coefficient of friction (hardness). The second friction unit exhibits higher high-temperature resistance and thermal stability, effectively resisting the heat generated by high-temperature friction, preventing brake disc performance degradation or deformation due to high temperatures, and extending the service life of the brake disc.

[0237] In some embodiments, the particle size of the aluminum matrix 1000 and the ceramic reinforcing phase in the first friction unit are not the same. Since the main function of the aluminum matrix 1000 is to provide strength and stiffness and to withstand heat transfer and mechanical stress from the friction layer 2000, a finer particle size of the ceramic reinforcing phase is required to give the aluminum matrix 1000 higher density and strength, improving its thermal shock resistance and fatigue resistance. In the aluminum matrix 1000, the particle size of the ceramic reinforcing phase is any value within the range of [5 μm, 50 μm]. The main function of the first friction unit is to provide frictional performance, generating sufficient frictional force for braking. A larger particle size of the ceramic reinforcing phase is beneficial for improving the wear resistance and thermal fading resistance of the first friction unit, while also maintaining a certain roughness and increasing the coefficient of friction. In the first friction unit, the particle size of the ceramic reinforcing phase is any value within the range of [50 μm, 300 μm].

[0238] In some embodiments, as shown in FIG7, in the brake disc provided in some embodiments of this disclosure, the second friction unit includes a plurality of second sub-friction units 2002, the first friction unit includes a plurality of first sub-friction units 2001 arranged at intervals, and the second sub-friction units 2002 are disposed between two adjacent first sub-friction units 2001. Thus, the surface of the aluminum substrate 1000 forms a friction layer integrally formed by the spaced distribution of the first sub-friction units 2001 and the second sub-friction units 2002.

[0239] Multiple second sub-friction units 2002 have the same shape, and the spacing between any two adjacent second sub-friction units 2002 is equal. The area ratio of a single first sub-friction unit 2001 to a single second sub-friction unit 2002 is in the range of [1:9, 7:3]. This ratio is the same as the area ratio of the first friction unit to the second friction unit, thereby ensuring the uniformity of wear when the friction layer is subjected to force.

[0240] In some embodiments, the shape of the second friction unit includes a fan shape, a square shape, or a circle. The second sub-friction unit 2002 is spaced apart from the first sub-friction unit 2001, which helps to release thermal stress and alleviate the problem of the second sub-friction unit 2002 detaching due to thermal mismatch during continuous braking, thereby improving the mechanical strength and wear resistance of the entire brake disc. The aluminum-based composite brake disc provided in some embodiments of this disclosure, tested according to the aluminum-ceramic disc group standard T / CAAMTB90-2022, shows an average friction coefficient ≥0.39 at 500℃; the aluminum-based composite brake disc shows an average friction coefficient ≥0.39 at 25℃.

[0241] In some embodiments, the second friction unit may include multiple second sub-friction units, with the orthographic projection of the first friction unit on the aluminum substrate surrounding the orthographic projection of the second sub-friction units on the aluminum substrate. That is, the first friction unit is an integral structure, and multiple second sub-friction units are uniformly embedded in the first friction unit. The spacing between any two adjacent second sub-friction units is maintained in the range of [2mm, 100mm]. In some embodiments, the spacing between any two adjacent second sub-friction units is in the range of [5mm, 20mm].

[0242] The aluminum-based composite brake discs provided in some embodiments of this disclosure form a new brake disc friction layer by combining a first friction unit and a second friction unit. The spaced first and second friction units improve the friction coefficient of the friction layer, while the spaced second friction units help release thermal stress and alleviate the problem of second friction unit detachment caused by thermal mismatch. Compared with traditional iron-based brake discs, reducing the weight of aluminum-based composite materials can effectively reduce the overall weight of the vehicle, reduce fuel consumption, and improve fuel economy. Furthermore, by adjusting the volume fraction of the ceramic reinforcing phase in the aluminum matrix and the first friction unit, as well as the composition of the second friction unit, the friction coefficient and thermal stability of the brake disc can be adjusted to meet the needs of customized vehicles and usage scenarios.

[0243] This disclosure provides a preparation method according to some embodiments, as shown in FIG8. The preparation method includes:

[0244] S1. Prepare the first raw material powder and the second raw material powder that make up the aluminum matrix and the first friction unit respectively according to the proportion, and perform mechanical processing on the hard ceramic or iron to form the second friction unit that meets the size requirements.

[0245] S2. According to the structure of the aluminum-based composite brake disc, the first raw material powder and the second raw material powder are laid in the mold, and any pressure value within the pressure range of [10MPa, 50MPa] is applied. The pressure is held for any duration of [1min, 5min] to form a green block and then removed.

[0246] S3. Place the green block at any temperature value between [800℃ and 1000℃] and sinter for any duration between [3h and 5h]. After cooling to room temperature, the aluminum ceramic plate skeleton is obtained.

[0247] S4. Machining is performed on the surface of the aluminum ceramic disc skeleton to form multiple holes for embedding the second sub-friction unit, and the second sub-friction unit is embedded in the multiple holes.

[0248] S5. Transfer the aluminum ceramic disc skeleton with the second sub-friction unit into the aluminum alloy melt, apply any pressure value within the range of [5MPa, 10MPa], and keep it heated and pressured for any duration of [10min, 60min] before taking it out to obtain the aluminum-based composite brake disc.

[0249] In some embodiments, the first raw material powder used to prepare the aluminum matrix is ​​composed of a ceramic reinforcing phase with a particle size of any value in [5 μm, 50 μm], an organic binder, a high-temperature inorganic binder, and a pore-forming agent in a volume ratio of 20-70 / 2-10 / 5-20 / 10-40. The second raw material powder is composed of a ceramic reinforcing phase with a particle size of any value in [50 μm, 300 μm], an organic binder, a high-temperature inorganic binder, and a pore-forming agent in a volume ratio of 50-90 / 2-10 / 5-20 / 5-35.

[0250] Here, the organic binder includes at least one of polyvinyl alcohol, polyvinyl butyral, and carboxymethyl cellulose; the inorganic binder includes at least one of aluminum dihydrogen phosphate, sodium silicate, calcium aluminate, and tetraethyl orthosilicate; and the pore-forming agent includes at least one of ammonium bicarbonate, soluble starch, sucrose, polymethyl methacrylate, and toner.

[0251] In some embodiments of this disclosure, according to the outer diameter, inner diameter, and total thickness of the aluminum-based composite brake disc to be prepared, and based on the positional relationship between the friction layer and the aluminum substrate, the corresponding raw material powders are sequentially laid in a mold, pressed into a green block, and then removed. In some embodiments, after sintering the green block to form it, an aluminum-ceramic disc skeleton is obtained. According to the size of the second sub-friction unit, multiple holes that can be embedded in the second sub-friction unit are mechanically machined on the surface corresponding to the friction layer of the aluminum-ceramic disc skeleton.

[0252] It should be noted that the holes for embedding the second sub-friction units are uniformly distributed on the surface of the aluminum ceramic disc skeleton, and the spacing between the holes is controlled within [1mm, 100mm]. In some embodiments, the spacing between the holes is controlled within [5mm, 20mm]. The shape of the holes matches the shape of the second friction units. Finally, the aluminum ceramic disc skeleton with multiple second sub-friction units embedded is placed in a graphite mold, preheated, and then impregnated with molten aluminum alloy. Under pressure, the molten aluminum alloy permeates into the aluminum ceramic disc skeleton, ultimately forming an aluminum-based composite brake disc in which the aluminum element exists in the form of a continuously distributed aluminum alloy. Under the action of molten aluminum alloy impregnation, the bonding strength between the second friction unit and the first friction unit is greatly improved.

[0253] In some embodiments, based on the different depths of the holes used to embed the second sub-friction unit during preparation, the second sub-friction unit has a different height relationship with the first sub-friction unit after being placed in the hole. When the aluminum alloy melt is subsequently infiltrated into the aluminum ceramic disc skeleton (step S5), the insufficient part in the friction layer is supplemented by aluminum alloy, so that the final friction layer is a flat structure.

[0254] In some embodiments, based on the preparation process, only the first raw material powder constituting the aluminum matrix is ​​used to prepare the green block (steps S1-S2 and without the machining process of step S4), that is, the resulting friction layer may not contain the first friction unit (aluminum alloy material with ceramic reinforcement phase), that is, the brake disc is composed of an aluminum matrix, multiple second friction units and aluminum alloy material in the gaps between the second friction units, and the second friction units have improved adhesion under the wrapping of aluminum alloy material.

[0255] Some embodiments of this disclosure also provide a vehicle braking system, including the aforementioned brake disc.

[0256] Some embodiments of this disclosure also provide a vehicle that includes the vehicle braking system described above.

[0257] To enable those skilled in the art to more clearly understand this disclosure, the following embodiments will be used to provide a detailed description of an aluminum-based composite, brake disc, vehicle braking system, and vehicle in some embodiments of this disclosure.

[0258] Example 7

[0259] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum matrix) is mixed at a weight ratio of 20μm silicon carbide / polyvinyl butyral (PVB) / aluminum dihydrogen phosphate / starch = 60 / 5 / 15 / 20. The second raw material powder (the raw material that constitutes the first friction unit) is mixed at a weight ratio of 100μm silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 80 / 5 / 10 / 5.

[0260] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm, and a second raw material powder thickness of 5 mm. The green structure block is then removed.

[0261] The green block was sintered in air at 900℃ for 4 hours and cooled to room temperature to obtain an aluminum ceramic disc skeleton. The upper and lower surfaces of the aluminum ceramic disc skeleton were machined to grind out 8 fan-shaped holes with an outer diameter of 350mm, an inner diameter of 150mm, a spacing of 10mm, and a height of 2.5mm. The total area of ​​the holes accounted for 0.7 of the disc surface area.

[0262] A fan-shaped HT250 cast iron sheet of uniform size, 2.5 mm thickness, and 200 HB hardness was placed into the hole and then placed in a graphite mold. The mold was preheated to 600 degrees Celsius and then immersed in molten aluminum alloy at a pressure of 8 MPa for 30 minutes at 750 degrees Celsius. This resulted in an aluminum-based composite material with an aluminum matrix in the middle and friction layers on both sides. The friction layer, composed of the second raw material powder, had a hardness of 170 HB. The resulting structure is shown in Figure 7.

[0263] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB90-2022.

[0264] Example 8

[0265] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum-based matrix) is mixed at a weight ratio of 20μm alumina / PVB / aluminum dihydrogen phosphate / starch = 60 / 5 / 15 / 20, and the second raw material powder (the raw material that constitutes the first friction unit) is mixed at a weight ratio of 100μm silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 80 / 5 / 10 / 5.

[0266] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm, and a second raw material powder thickness of 5 mm. The green structure block is then removed.

[0267] The green block was sintered in air at 900℃ for 4 hours and cooled to room temperature to obtain an aluminum ceramic plate skeleton. Eight fan-shaped holes with an outer diameter of 350mm, an inner diameter of 150mm, a spacing of 20mm, and a height of 2.5mm were machined and polished on the upper and lower surfaces of the skeleton. The total area of ​​the holes accounted for 0.9 of the plate surface area.

[0268] Fan-shaped alumina particles of uniform size, 5mm thickness, and 600HB hardness were placed into the holes of the skeleton and then placed in a graphite mold. The mold was preheated to 600℃ and then immersed in molten aluminum alloy at a pressure of 8MPa. The mixture was then held at 750℃ for 30 minutes to obtain an aluminum-based composite with an aluminum matrix in the middle and friction layers on both sides. The friction layers, composed of the second raw material powder, had a hardness of 170HB. The resulting structure is shown in Figure 1.

[0269] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB90-2022.

[0270] Example 9

[0271] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum matrix) is mixed at a weight ratio of 20-micron silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 60 / 5 / 15 / 20.

[0272] The first raw material powder was laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. It was pressed into a green block at room temperature under a pressure of 30 MPa for 5 minutes and then removed. The final total thickness of the aluminum matrix was 30 mm.

[0273] The green block was sintered in air at 900°C for 4 hours and then cooled to room temperature to obtain the aluminum ceramic plate skeleton.

[0274] Eight HT350 cast iron sheets, each with an outer diameter of 350 mm, an inner diameter of 150 mm, a central angle of 30 degrees, a thickness of 5 mm, and a hardness of 310 HB, were placed on a frame. The total area of ​​the cast iron sheets occupied 0.7 times the area of ​​the plate. The plate was positioned using a graphite mold, preheated to 600°C, and then immersed in molten aluminum alloy at a pressure of 8 MPa for 30 minutes at a holding temperature of 750°C. The hardness of the aluminum alloy was 70 HB.

[0275] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB90-2022.

[0276] Example 10

[0277] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum-based matrix) is mixed in a weight ratio of 20-micron silicon carbide / alumina fiber / PVB / aluminum dihydrogen phosphate / starch = 40 / 20 / 5 / 15 / 20. The second raw material powder (the raw material that constitutes the first friction unit) is mixed in a weight ratio of 100-micron silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 80 / 5 / 10 / 5.

[0278] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm, and a second raw material powder thickness of 5 mm. The green structure block is then removed.

[0279] The green block was sintered in air at 900℃ for 4 hours and cooled to room temperature to obtain an aluminum ceramic disc skeleton. Eight square friction pad holes with a side length of 150mm, a spacing of 50mm, and a height of 2.5mm were machined and ground on the upper and lower surfaces of the skeleton. The total area of ​​the holes accounted for 0.5 of the disc surface area.

[0280] HT250 cast iron sheets of uniform size, 5mm thickness, and 200HB hardness were placed into the holes and then placed in a graphite mold. The mold was preheated to 600 degrees Celsius and then immersed in molten aluminum alloy at a pressure of 8MPa. The mixture was held at 750°C for 30 minutes to obtain an aluminum-based composite with an aluminum matrix in the middle and friction layers on both sides. The friction layers, composed of the second raw material powder, had a hardness of 160HB. The resulting structure is shown in Figure 9.

[0281] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB 90-2022.

[0282] Example 11

[0283] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum-based matrix) is 6061 aluminum alloy powder, and the second raw material powder (the raw material that makes up the first friction unit) is prepared in a weight ratio of 100-micron silicon carbide / PVB / sodium silicate / polymethyl methacrylate = 80 / 5 / 10 / 5.

[0284] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm, and a second raw material powder thickness of 5 mm. The green structure block is then removed.

[0285] The green block was sintered in air at 900℃ for 4 hours and then cooled to room temperature to obtain an aluminum ceramic disc skeleton. Sixteen fan-shaped holes with an outer diameter of 350mm, an inner diameter of 150mm, a spacing of 2mm, and a height of 2.5mm were machined and polished on the upper and lower surfaces of the skeleton. The total area of ​​the holes accounted for 0.8 of the disc surface area.

[0286] A fan-shaped HT250 cast iron sheet of uniform size, 2.5 mm thickness, and 200 HB hardness was placed into the fan-shaped hole and then placed in a graphite mold. The mold was preheated to 600 degrees Celsius and then immersed in molten aluminum alloy at a pressure of 8 MPa. The mixture was held at 750 degrees Celsius for 30 minutes to obtain an aluminum-based composite material with an aluminum matrix in the middle and friction layers on both sides. The friction layer, composed of the second raw material powder, had a hardness of 170 HB. The resulting structure is shown in Figure 10.

[0287] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB 90-2022.

[0288] Example 12

[0289] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum matrix) is mixed at a weight ratio of 20μm silicon carbide / PVB / aluminum dihydrogen phosphate / polymethyl methacrylate = 30 / 5 / 15 / 50. The second raw material powder (the raw material that constitutes the first friction unit) is mixed at a weight ratio of 100μm silicon carbide / PVB / aluminum dihydrogen phosphate / pore-forming agent = 80 / 5 / 10 / 5.

[0290] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm, and a second raw material powder thickness of 5 mm. The green structure block is then removed.

[0291] The green block was sintered in air at 900℃ for 4 hours and then cooled to room temperature to obtain an aluminum ceramic disc skeleton. Sixteen fan-shaped holes with an inner diameter of 150mm, a spacing of 10mm, and a height of 2.5mm were machined and polished on the upper and lower surfaces of the skeleton. The total area of ​​the holes accounted for 0.8 of the machined surface area.

[0292] A fan-shaped HT350 cast iron sheet of uniform size, 2.5 mm thickness, and 220 HB hardness was placed into the hole and then placed in a graphite mold. The mold was preheated to 600℃ and then immersed in molten aluminum alloy at a pressure of 8 MPa. The mixture was then held at 750℃ for 30 minutes to obtain an aluminum-based composite material with an aluminum matrix in the middle and friction layers on both sides. The friction layers, composed of the second raw material powder, had a hardness of 180 HB. The resulting structure is shown in Figure 10.

[0293] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB 90-2022.

[0294] Example 13

[0295] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum-based matrix) is mixed at a weight ratio of 20μm silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 60 / 5 / 15 / 20, and the second raw material powder (the raw material that constitutes the first friction unit) is mixed at a weight ratio of 100μm silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 80 / 5 / 10 / 5.

[0296] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm, and a second raw material powder thickness of 5 mm. The green structure block is then removed.

[0297] The green block was sintered in air at 900℃ for 4 hours and cooled to room temperature to obtain an aluminum ceramic disc skeleton. The upper and lower surfaces of the aluminum ceramic disc skeleton were machined to grind out 8 fan-shaped holes with an outer diameter of 350mm, an inner diameter of 150mm, a spacing of 10mm, and a height of 2.5mm. The total area of ​​the holes accounted for 0.7 of the disc surface area.

[0298] A fan-shaped HT200 cast iron sheet of uniform size, 2.5 mm thickness, and 180 HB hardness was placed into the hole and then placed in a graphite mold. The mold was preheated to 600 degrees Celsius and then immersed in molten aluminum alloy at a pressure of 8 MPa for 30 minutes at 750 degrees Celsius. This resulted in an aluminum-based composite material with an aluminum matrix in the middle and friction layers on both sides. The friction layer, composed of the second raw material powder, had a hardness of 170 HB. The resulting structure is shown in Figure 7.

[0299] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB 90-2022.

[0300] Example 14

[0301] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum-based matrix) is mixed at a weight ratio of 20μm silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 60 / 5 / 15 / 20, and the second raw material powder (the raw material that constitutes the first friction unit) is mixed at a weight ratio of 100μm silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 80 / 5 / 10 / 5.

[0302] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm, and a second raw material powder thickness of 5 mm. The green structure block is then removed.

[0303] The green block was sintered in air at 900℃ for 4 hours and cooled to room temperature to obtain an aluminum ceramic disc skeleton. The upper and lower surfaces of the aluminum ceramic disc skeleton were machined to grind out 8 fan-shaped holes with an outer diameter of 350mm, an inner diameter of 150mm, a spacing of 10mm, and a height of 2.5mm. The total area of ​​the holes accounted for 0.7 of the disc surface area.

[0304] Alumina sheets of uniform size, 2.5 mm thickness, and 1200 HB hardness were placed into the holes and then placed in a graphite mold. The mold was preheated to 600 degrees Celsius and then immersed in molten aluminum alloy at a pressure of 8 MPa for 30 minutes at 750 degrees Celsius. This resulted in an aluminum-based composite material with an aluminum matrix in the middle and friction layers on both sides. The friction layers, composed of the second raw material powder, had a hardness of 170 HB. The resulting structure is shown in Figure 7.

[0305] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB 90-2022.

[0306] Example 15

[0307] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum-based matrix) is mixed at a weight ratio of 20μm silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 60 / 5 / 15 / 20, and the second raw material powder (the raw material that constitutes the first friction unit) is mixed at a weight ratio of 100μm silicon carbide / PVB / aluminum dihydrogen phosphate / starch = 80 / 5 / 10 / 5.

[0308] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in a ring mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm, and a second raw material powder thickness of 5 mm. The green structure block is then removed.

[0309] The green block was sintered in air at 900℃ for 4 hours and cooled to room temperature to obtain an aluminum ceramic disc skeleton. The upper and lower surfaces of the aluminum ceramic disc skeleton were machined to grind out 8 fan-shaped holes with an outer diameter of 350mm, an inner diameter of 150mm, a spacing of 10mm, and a height of 2.5mm. The total area of ​​the holes accounted for 0.3 of the disc surface area.

[0310] A fan-shaped HT250 cast iron sheet of uniform size, 2.5 mm thickness, and 200 HB hardness was placed into the hole and then placed in a graphite mold. The mold was preheated to 600 degrees Celsius and then immersed in molten aluminum alloy at a pressure of 8 MPa for 30 minutes at 750 degrees Celsius. This resulted in an aluminum-based composite material with an aluminum matrix in the middle and friction layers on both sides. The friction layer, composed of the second raw material powder, had a hardness of 170 HB. The resulting structure is shown in Figure 7.

[0311] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB 90-2022.

[0312] Comparative Example 3

[0313] The raw material powders used to prepare aluminum-based composite brake discs are mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum-based matrix) is mixed at a weight ratio of 20-micron silicon carbide / PVB / aluminum dihydrogen phosphate / pore-forming agent = 60 / 5 / 15 / 20, and the second raw material powder (the raw material that makes up the friction layer) is mixed at a weight ratio of 100-micron silicon carbide / PVB / aluminum dihydrogen phosphate / pore-forming agent = 80 / 5 / 10 / 5.

[0314] Following the laying sequence, the second raw material powder, the first raw material powder, and the second raw material powder are sequentially laid in layers in an annular mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and the pressure is maintained for 5 minutes to form a three-layer green structure block with a total thickness of 40 mm, a first raw material powder thickness of 30 mm in the middle, and a second raw material powder thickness of 5 mm on both sides. The green structure block is then removed.

[0315] The green block was sintered in air at 900 degrees Celsius for 4 hours and then cooled to room temperature to obtain the aluminum ceramic plate skeleton.

[0316] The skeleton is placed in a graphite mold, preheated to 600 degrees Celsius, and then immersed in molten aluminum alloy at an immersion pressure of 8 MPa for 30 minutes.

[0317] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB 90-2022.

[0318] Comparative Example 4

[0319] The raw material powders used to prepare aluminum-based composite brake discs were mixed in a three-dimensional motion mixer. The first raw material powder (used to prepare the aluminum matrix) was mixed at a weight ratio of 20μm silicon carbide / PVB / aluminum dihydrogen phosphate / pore-forming agent = 60 / 5 / 15 / 20.

[0320] The first raw material powder is laid in an annular mold with an outer diameter of 350 mm and an inner diameter of 150 mm. At room temperature, a pressure of 30 MPa is applied and held for 5 minutes to form a single-layer green structure block with a total thickness of 30 mm, which is then removed.

[0321] The green block was sintered in air at 900°C for 4 hours and then cooled to room temperature to obtain the aluminum ceramic plate skeleton.

[0322] Place HT250 ring-shaped cast iron sheets of uniform size, 2.5mm thickness, and 200HB hardness on the upper and lower layers of the skeleton, and put them into the graphite mold. Preheat to 600℃, immerse in molten aluminum alloy, with an immersion pressure of 8MPa and a holding time of 30min.

[0323] The coefficient of friction and wear rate of aluminum ceramic discs were tested in accordance with the group standard T / CAAMTB 90-2022.

[0324] Table 2. Friction coefficient and wear rate of aluminum-based composite brake discs

[0325] Table 2 shows the friction coefficient and wear rate of the aluminum ceramic discs tested according to the national standard T / CAAMTB90-2022. As shown in Table 2, the brake discs prepared in Examples 7-15 were tested for friction coefficient and wear rate on the MFT-5000 friction and wear testing machine, and met the requirements of GB / T 344-2017 for the friction coefficient and wear rate of automotive brake discs. Comparative Example 3, because its friction layer is entirely composed of aluminum-based material reinforced with high volume fraction silicon carbide, has a lower friction coefficient at both room temperature and high temperature, and its wear is relatively large. In Comparative Example 4, because the friction pad is integrally bonded to the aluminum substrate, the friction pad detached during the friction test, seriously affecting the brake disc performance.

[0326] Currently, brake discs are mainly made of cast iron or carbon ceramic. While these materials offer good wear resistance and high-temperature resistance, they also suffer from drawbacks such as high weight or high cost. To reduce the weight of brake discs and improve their heat dissipation and wear resistance, aluminum-based composite materials have become an important material for brake discs. However, aluminum-based brake discs have poor high-temperature mechanical properties, which need to be improved.

[0327] This disclosure provides a brake disc with embodiments including a structural layer and a friction layer disposed on at least one side of the structural layer. The structural layer includes a first porous ceramic skeleton and a first aluminum-based material embedded within the pores of the first porous ceramic skeleton; the friction layer includes a second porous ceramic skeleton and a second aluminum-based material embedded within the pores of the second porous ceramic skeleton. The volume fraction of the first porous ceramic skeleton in the structural layer is V1, and the volume fraction of the second porous ceramic skeleton in the friction layer is V2, where V1 ≤ V2.

[0328] In some embodiments of the brake disc provided in this disclosure, the structural layer ensures the structural strength of the brake disc, while the friction layer provides sufficient frictional performance. The first and second porous ceramic skeletons provide good support performance, ensuring the structural strength of both the structural and friction layers while also being lightweight.

[0329] The volume ratio of the first porous ceramic skeleton in the structural layer is less than or equal to the volume ratio of the second ceramic skeleton in the friction layer, which can ensure the friction performance of the friction layer.

[0330] Furthermore, the ceramic phases in the first porous ceramic skeleton are interconnected, and the ceramic phases in the second porous ceramic skeleton are also interconnected, which improves the integrity of the structural layer and the friction layer. Moreover, through an embedding method, the first aluminum-based material fills the pores of the first porous ceramic skeleton, and the second aluminum-based material fills the pores of the second porous ceramic skeleton, thereby enhancing structural strength and overall wear resistance.

[0331] A brake disc may include two friction layers or one friction layer. When the brake disc includes two friction layers, the two friction layers are respectively disposed on opposite sides of the structural layer, while when the brake disc includes one friction layer, the friction layer may be disposed on one side of the structural layer.

[0332] In some embodiments, the volume percentage of the first porous ceramic skeleton in the structural layer ranges from [20%, 60%].

[0333] The structural layer provides structural strength to the brake disc and dissipates heat generated during braking. By setting the volume percentage of the first porous ceramic skeleton in the structural layer to [20%, 60%], the hardness and structural strength of the structural layer can be improved. Furthermore, the first porous ceramic skeleton exhibits good thermal stability, reducing thermal degradation during high-temperature braking and ensuring braking performance. The first aluminum-based material embedded within the pores of the first porous ceramic skeleton enhances the heat dissipation performance of the structural layer, ensuring the stability of the brake disc's braking performance. In addition, setting the volume percentage of the first porous ceramic skeleton in the structural layer to [20%, 60%] also contributes to the lightweighting of the brake disc.

[0334] For example, the volume percentage of the first porous ceramic framework in the structural layer can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60%.

[0335] In some embodiments, the volume percentage of the first porous ceramic skeleton in the structural layer ranges from [40%, 50%]. By setting the volume percentage of the first porous ceramic skeleton in the structural layer to [40%, 50%], the hardness and structural lightness of the structural layer can be improved, while maintaining good thermal stability, and this also helps to achieve the lightweighting of the brake disc.

[0336] The friction layer provides frictional properties to the brake disc, while the second porous ceramic skeleton possesses characteristics such as high hardness and high wear resistance. By setting the volume percentage of the second porous ceramic skeleton in the friction layer to [40%, 80%], the hardness and wear resistance of the friction layer can be guaranteed. Furthermore, the second porous ceramic skeleton helps improve the thermal stability of the friction layer, reducing heat fade and ensuring braking performance. A higher proportion of the second porous ceramic skeleton also helps maintain a stable coefficient of friction in the friction layer, improving braking stability.

[0337] For example, the volume percentage of the second porous ceramic skeleton in the friction layer can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%.

[0338] In some embodiments, the volume percentage of the second porous ceramic skeleton in the friction layer ranges from [65%, 75%]. By setting the volume percentage of the second porous ceramic skeleton in the friction layer to [65%, 75%], the hardness and wear resistance of the friction layer can be guaranteed, and good thermal stability can be maintained, while also contributing to the lightweighting of the brake disc.

[0339] In some embodiments, the first porous ceramic framework comprises silicon carbide and a first mullite. The volume fraction of the first mullite in the structural layer is V3, and the volume fraction of the first aluminum-based material in the structural layer is V4. Here, V3 = -0.5V4. 2 +0.5V4+k; where -0.03 < k < 0.03, 40% ≤ V4 ≤ 80%.

[0340] The first porous ceramic framework comprises silicon carbide and first mullite. Silicon carbide is a high-performance ceramic material with advantages such as high hardness, high wear resistance, high corrosion resistance, high thermal conductivity, and low coefficient of thermal expansion. The inclusion of silicon carbide in the first porous ceramic framework ensures durability. Mullite is a mineral composed of aluminosilicates. Compared to silicon carbide, first mullite exhibits higher thermal stability, thus ensuring the stability and reliability of the first porous ceramic framework at high temperatures.

[0341] In some embodiments of this disclosure, the first aluminum-based material fills the pores in the first porous ceramic framework. Therefore, the volume ratio of the first aluminum-based material in the structural layer is equivalent to the volume ratio of the pores in the first porous ceramic framework in the structural layer. It is understood that the higher the pore ratio of the first porous ceramic framework, the lower its overall strength. This is achieved by ensuring that the proportion V3 of the first mullite in the structural layer and the proportion V4 of the first aluminum-based material in the structural layer satisfy the formula V3 = -0.5V4. 2 +0.5V4+k ensures that when the volume ratio of the first aluminum-based material in the structural layer is high, the proportion of the first mullite in the first porous ceramic skeleton is also high, thus ensuring the structural strength of the first porous ceramic skeleton. This helps to better embed the first aluminum-based material into the first porous ceramic skeleton, and the structure of the first porous ceramic skeleton is not easily damaged during the embedding process.

[0342] For example, when the volume ratio of the first aluminum-based material in the structural layer is 80% and the volume ratio of the first porous ceramic skeleton in the structural layer is 20%, according to the formula V3 = -0.5V4 2 +0.5V4+k yields a volume percentage of mullite greater than 5% and less than 11% in the structural layer. Correspondingly, silicon carbide accounts for a volume percentage greater than 9% and less than 15% in the structural layer. When the volume percentage of the first aluminum-based material and the first porous ceramic framework in the structural layer is both 40%, according to the formula V3 = -0.5V4... 2 By applying +0.5V⁴+k, the volume percentage of mullite in the first structural layer is greater than 9% and less than 15%. Correspondingly, the volume percentage of silicon carbide in the structural layer is greater than 45% and less than 51%.

[0343] It can be seen that the higher the volume ratio of the first aluminum-based material in the structural layer, the higher the proportion of the first mullite in the first porous ceramic skeleton (i.e., the volume ratio of the first mullite in the first porous ceramic skeleton), and the higher the structural strength of the first porous ceramic skeleton. This can reduce the damage to the first porous ceramic skeleton when the first aluminum-based material is embedded in it.

[0344] In some embodiments, the second porous ceramic framework comprises silicon carbide and a second mullite. The volume fraction of the second mullite in the friction layer is V5, and the volume fraction of the second aluminum-based material in the friction layer is V6. V5 = -0.5V6 2 +0.5V6+k; where -0.03<k<0.03, 20%≤V6≤60%.

[0345] In some embodiments of this disclosure, since the second aluminum-based material fills the pores in the second porous ceramic framework, the volume ratio of the second aluminum-based material in the structural layer is equivalent to the volume ratio of the pores in the second porous ceramic framework in the structural layer. It is understood that the higher the pore ratio of the second porous ceramic framework, the lower its overall strength. This is achieved by ensuring that the proportion V5 of the second mullite in the friction layer and the proportion V6 of the second aluminum-based material in the friction layer satisfy the formula V5 = -0.5V6. 2 +0.5V6+k ensures that when the volume ratio of the second aluminum-based material in the friction layer is high, the proportion of the second mullite in the second porous ceramic skeleton is also high, thus ensuring the structural strength of the second porous ceramic skeleton. This helps to better embed the second aluminum-based material into the second porous ceramic skeleton, and the structure of the second porous ceramic skeleton is not easily damaged during the embedding process.

[0346] For example, when the volume percentage of the second aluminum-based material in the friction layer is 60% and the volume percentage of the second porous ceramic skeleton in the friction layer is 40%, according to the formula V5 = -0.5V6 2 +0.5V6+k yields a second mullite volume fraction in the friction layer that is greater than 9% and less than 15%. Correspondingly, silicon carbide has a volume fraction greater than 25% and less than 31%. When the second aluminum-based material has a volume fraction of 20% in the friction layer and the second porous ceramic framework has a volume fraction of 80% in the structural layer, according to the formula V5 = -0.5V6... 2 By applying +0.5V6+k, the volume percentage of the second mullite in the friction layer is greater than 5% and less than 11%. Correspondingly, the volume percentage of silicon carbide in the friction layer is greater than 69% and less than 75%.

[0347] It can be seen that the higher the volume ratio of the second aluminum-based material in the structural layer, the higher the proportion of the second mullite in the second porous ceramic skeleton (i.e., the volume ratio of the second mullite in the second porous ceramic skeleton), and the higher the structural strength of the second porous ceramic skeleton. This can reduce the damage to the second porous ceramic skeleton when the second aluminum-based material is embedded in it.

[0348] In some embodiments, the first mullite is generated from silicon carbide and alumina. That is, the first mullite is generated by the reaction of silicon carbide and alumina in a first porous ceramic framework. The generated first mullite is located on the surface of silicon carbide particles, protecting the silicon carbide particles. At the same time, the first mullite can also connect adjacent silicon carbide particles to form a porous framework structure.

[0349] In some embodiments, the first mullite can be formed by in-situ sintering of silicon carbide and alumina. In this process, silicon carbide first reacts with oxygen to form a dense silicon oxide film on the surface of the silicon carbide particles, as shown in Chemical Formula 1: SiC + O2 → SiO2 + CO2 (Chemical Formula 1)

[0350] Silicon oxide reacts with aluminum oxide to form mullite, an aluminosilicate, as shown in chemical formula II: 2SiO2 + 3Al2O3 → mullite (chemical formula II).

[0351] The first mullite coating is applied to the surface of the silicon carbide particles, connecting adjacent silicon carbide particles into a whole, thereby ensuring the structural strength of the first porous ceramic skeleton.

[0352] In some embodiments, the second mullite is generated from silicon carbide and aluminum oxide.

[0353] Similar to the first mullite, the second mullite is also generated in situ on the silicon carbide surface, ensuring the structural strength of the second porous ceramic skeleton.

[0354] In some embodiments, the raw materials for the first porous ceramic framework include silicon carbide, alumina, and a pore-forming agent.

[0355] The first porous ceramic framework constitutes a relatively low proportion of the structural layer, meaning it has a high porosity. To ensure the first porous ceramic framework achieves the required porosity, its raw materials include silicon carbide, alumina, and a pore-forming agent. Here, silicon carbide serves as the substrate for the first porous ceramic framework, alumina reacts with silicon carbide to form the first mullite, and the pore-forming agent enables the first porous ceramic framework to possess a suitable porosity.

[0356] In some embodiments, the pore-forming agent may be polymethyl methacrylate (PMMA). PMMA is used as a raw material for the first porous ceramic framework, mixed with other components, and after sintering, the PMMA is removed, thereby forming pores.

[0357] In some embodiments, the raw materials for the second porous ceramic framework include silicon carbide and alumina.

[0358] The second porous ceramic framework has a relatively low porosity, so it does not require the addition of a separate pore-forming agent. Instead, it utilizes the gases and other reactions generated during the sintering process of silicon carbide and alumina to form pores.

[0359] In some embodiments, in order to ensure that the raw materials of the first porous ceramic framework and the second porous ceramic framework are evenly dispersed, the raw materials of the first porous ceramic framework and the second porous ceramic framework further include a dispersant.

[0360] In some embodiments, the particle size range of silicon carbide in the first porous ceramic framework is [0.5 μm, 100 μm]. By selecting silicon carbide with a particle size range of [0.5 μm, 100 μm] as the raw material of the first porous ceramic framework, the silicon carbide can be fully dispersed, ensuring higher porosity, and the strength of the first porous ceramic framework can be improved through dispersion strengthening.

[0361] In some embodiments, the second porous ceramic framework includes at least two types of silicon carbide with different particle sizes, and the particle size range of the silicon carbide in the second porous ceramic framework is [0.5 μm, 100 μm]. The second porous ceramic framework is disposed in the friction layer, and by including at least two types of silicon carbide with different particle sizes, it helps to form a more complex friction interface in the friction layer, thereby maintaining a stable coefficient of friction. Furthermore, the addition of silicon carbide with different particle sizes also enables the formation of a denser surface in the friction layer, improving the wear resistance of the friction layer. In addition, the interaction of silicon carbide with different particle sizes also helps to improve braking smoothness and thermal stability.

[0362] In some embodiments, the second porous ceramic framework includes silicon carbide with a particle size range of [10 μm, 30 μm] and silicon carbide with a particle size range of [70 μm, 100 μm]. For example, the second porous ceramic framework includes small-particle-size (particle size range of [10 μm, 30 μm]) silicon carbide and large-particle-size (particle size range of [70 μm, 100 μm]) silicon carbide, which makes the friction layer form a complex friction interface, ensuring a stable coefficient of friction, and making the friction layer form a denser surface, thereby improving wear resistance.

[0363] In some embodiments, the pore size range of the pores in the first porous ceramic framework is [5μm, 50μm]. By controlling the pore size within the range of [5μm, 50μm], the structural strength of the first porous ceramic framework can be guaranteed, while also facilitating the embedding of the first aluminum-based material into the first porous ceramic framework.

[0364] In some embodiments, the pore size range of the pores in the second porous ceramic framework is [5 μm, 50 μm]. Similar to the first porous ceramic framework, the pore size range of the second porous ceramic framework is also set to [5 μm, 50 μm].

[0365] It should be noted that the pore diameter in the first and second porous ceramic frameworks refers to the diameter of the pores.

[0366] In some embodiments, the porosity of the first porous ceramic skeleton ranges from [40%, 80%]. It is understood that since the first aluminum-based material is embedded within the pores of the first porous ceramic skeleton, the higher the porosity of the first porous ceramic skeleton, the higher the volume percentage of the first aluminum-based material in the structural layer. By setting the porosity range of the first porous ceramic skeleton to [40%, 80%], the content of the first aluminum-based material in the structural layer can be guaranteed, resulting in higher structural strength of the structural layer. Furthermore, the structural strength of the first porous ceramic skeleton can be ensured before the first aluminum-based material is embedded, reducing the risk of damage to the first porous ceramic skeleton.

[0367] In some embodiments, the porosity of the second porous ceramic skeleton ranges from [20%, 60%]. Similar to the first porous ceramic skeleton, setting the porosity range of the second porous ceramic skeleton to [20%, 60%] ensures the content of the second aluminum-based material in the friction layer, resulting in higher structural strength of the friction layer. Furthermore, it ensures the structural strength of the second porous ceramic skeleton before embedding the second aluminum-based material, reducing the risk of damage to the second porous ceramic skeleton.

[0368] In some embodiments, the thickness of the structural layer ranges from 10mm to 50mm. By setting the thickness of the structural layer within this range, it is possible to ensure the structural strength of the structural layer, ensure that the brake disc can maintain stable braking performance under conditions such as high temperature and high pressure, reduce the safety hazard of brake disc breakage, ensure its durability, and keep the brake disc lightweight.

[0369] In some embodiments, the thickness of a single friction layer is less than or equal to 10 mm. By controlling the thickness of the single friction layer to less than 10 mm, faster heat conduction can be achieved, improving heat dissipation performance. While ensuring braking performance, the overall thickness of the brake disc can be reduced, friction can be generated more quickly, and the sensitivity of braking response can be improved.

[0370] It is understood that in some embodiments of this disclosure, there is no clear boundary between the structural layer and the friction layer. The composition of the structural layer and the friction layer can be the same, differing only in the proportion of the ceramic phase. Furthermore, the structural layer and the friction layer can also be the same, such as the volume percentage of the first porous ceramic skeleton in the structural layer being [20%, 60%], and the volume percentage of the second porous ceramic skeleton in the friction layer being [40%, 80%], with overlapping ranges between the two.

[0371] In some embodiments, the first aluminum-based material comprises an aluminum alloy. Aluminum alloys have a low density, and using them as the first aluminum-based material in the structural layer helps to achieve a lighter brake disc. Furthermore, aluminum alloys have excellent thermal conductivity, facilitating the timely conduction of heat generated during braking by the structural layer, thus improving heat dissipation.

[0372] In some embodiments, the second aluminum-based material comprises an aluminum alloy. Similar to the second aluminum-based material, when aluminum alloys are used in the friction layer, they can also achieve weight reduction and improved heat dissipation. At the same time, aluminum alloys also have good wear resistance, which can extend the service life of the friction layer.

[0373] In some embodiments, the friction coefficient of the brake disc ranges from [0.30, 0.45]. Setting the friction coefficient of the brake disc to [0.30, 0.45] ensures that the brake disc has sufficient braking force, reduces braking distance during braking, and maintains a stable friction coefficient, thus ensuring the continuity and stability of braking force.

[0374] In some embodiments, the friction coefficient of the brake disc is in the range of [0.40, 0.45]. Setting the friction coefficient of the brake disc to the range of [0.40, 0.45] ensures that the brake disc has sufficient braking force, reduces the braking distance during braking, and thus ensures the continuity and stability of braking force.

[0375] In some embodiments, the four-point bending strength of the brake disc at 300°C is greater than 230 MPa. In high-temperature environments, the brake disc needs to withstand significant thermal and mechanical stresses. By ensuring that the four-point bending strength of the brake disc at 300°C is greater than 230 MPa, the brake disc can maintain stability, reduce heat fade caused by high temperatures, and improve the safety performance of the brake disc.

[0376] This disclosure also provides a method for manufacturing a brake disc, comprising:

[0377] Provide raw materials for the first porous ceramic framework and the second porous ceramic framework;

[0378] The raw materials of the first porous ceramic skeleton and the raw materials of the second porous ceramic skeleton are placed in a mold and pressed to obtain a green body structure.

[0379] The green structure is sintered to form a sintered billet;

[0380] Molten aluminum-based material is infiltrated into a sintered blank, and the brake disc is obtained after solidification.

[0381] In some embodiments of this disclosure, the raw materials for the first and second porous ceramic skeletons are first pressed in a mold to obtain a green structure. The green structure is then sintered, allowing the raw materials to solidify and forming a sintered blank containing the first and second porous ceramic skeletons. Molten aluminum-based material is then infiltrated into the porous sintered blank using pressure infiltration, thereby obtaining a brake disc. The preparation method provided in some embodiments of this disclosure is simple and can fill the pores in the first and second porous ceramic skeletons with aluminum-based material through pressure infiltration, achieving lightweighting while improving the overall structural strength and wear resistance.

[0382] In some embodiments, the raw materials for the first porous ceramic framework include silicon carbide, alumina, and a pore-forming agent. Silicon carbide serves as the substrate of the first porous ceramic framework, alumina reacts with silicon carbide to form a first mullite, and the pore-forming agent enables the first porous ceramic framework to have a suitable porosity.

[0383] In some embodiments, the raw materials for the second porous ceramic framework include silicon carbide and alumina. Gases and other reactions generated during the sintering process of silicon carbide and alumina form the second porous ceramic framework with a porous structure.

[0384] In some embodiments, when the raw materials of the first porous ceramic framework and the second porous ceramic framework are placed in a mold for pressing, the raw material of the first porous ceramic framework can be pressed separately to form a first green body, and the raw material of the second porous ceramic framework can be pressed separately to form a second green body. When this method is adopted, the first green body and the second green body are subsequently sintered separately to form a first sintered blank and a second sintered blank. After the first sintered blank and the second sintered blank are assembled, molten aluminum-based material is simultaneously infiltrated into the first sintered blank and the second sintered blank. The first sintered blank and the second sintered blank are connected into a whole by the solidified aluminum-based material to obtain a brake disc.

[0385] Alternatively, the raw materials for the first and second porous ceramic skeletons can be placed sequentially into the same mold and then pressed into a single green structure. When this method is used, the green structure is subsequently sintered to form a sintered blank that includes both the first and second porous ceramic skeletons. Molten aluminum-based material is then infiltrated into the sintered blank, and after solidification, a brake disc is obtained. Using this method, a tighter connection can be formed between the first and second porous ceramic skeletons through sintering, thereby improving the structural strength of the structural and friction layers in the brake disc.

[0386] In some embodiments, sintering the green structure includes:

[0387] The green structure is sintered at any temperature between [1300℃ and 1700℃] for any duration between [1h and 4h].

[0388] During sintering, the surface of silicon nitride is oxidized to form a dense silicon oxide film. The silicon oxide film then reacts with alumina under high temperature conditions to form mullite. Choosing any sintering temperature from [1300℃, 1700℃] and any sintering time from [1h, 4h] allows silicon oxide and alumina to react fully to form mullite, while reducing defects such as overheating, deformation, or cracking.

[0389] In some embodiments, sintering is carried out in an air atmosphere or other oxygen-containing atmosphere, so that silicon nitride can react with oxygen to form an oxide scale.

[0390] In some embodiments, infiltrating molten aluminum-based material into a sintered billet includes:

[0391] Preheat the sintered billet to any value in [700℃, 1000℃] to obtain a preheated sintered billet;

[0392] The preheated sintered billet is placed in a preheated pressure infiltration mold, and molten aluminum-based material is poured in and pressed under a pressure greater than 100 MPa.

[0393] Preheating the sintered billet and the pressure infiltration mold ensures the temperature during the pressure infiltration process, reducing the problem of molten aluminum-based material cooling and solidifying upon contact with the relatively low-temperature sintered billet and mold. This allows the molten aluminum-based material to more easily enter the pores of the sintered billet. Pressing at a pressure greater than 100 MPa ensures high pressure infiltration efficiency, allowing the molten aluminum-based material to more fully penetrate the pores of the sintered billet.

[0394] This disclosure also provides a brake in some embodiments, including the brake disc as described above, or a brake disc manufactured by the method described above. The brakes provided in some embodiments of this disclosure have all the beneficial effects of the aforementioned brake discs, which will not be repeated here.

[0395] This disclosure also provides a vehicle in some embodiments, including the brake as described above. The vehicle provided in some embodiments of this disclosure has all the beneficial effects of the described brake disc, which will not be repeated here.

[0396] The following examples illustrate some embodiments of this disclosure. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0397] Unless otherwise specified, in the following examples and comparative examples, the proportions refer to mass percentages.

[0398] Example 16

[0399] In this embodiment, the components of the structural layer raw material include: 84% silicon carbide, 4% alumina, 2% stearic acid dispersant, and 10% PMMA; wherein the particle size of silicon carbide is 5 μm, the alumina is γ-Al2O3, and the particle size of alumina is 0.5 μm.

[0400] The components of the friction layer raw material include: 54% silicon carbide with a particle size of 100μm, 40% silicon carbide with a particle size of 20μm, 4% alumina, and 2% stearic acid dispersant.

[0401] a. Add silicon carbide, alumina, stearic acid dispersant and PMMA to anhydrous ethanol and disperse evenly, then dynamically dry at 60℃ to obtain the structural layer raw material.

[0402] b. Add silicon carbide, alumina and stearic acid dispersant to anhydrous ethanol and disperse evenly, then dynamically dry at 60°C to obtain the friction layer raw material.

[0403] c. The structural layer material and the friction layer material are filled into the mold. The friction layer material, structural layer material and friction layer material are laid in the mold in sequence. The mass ratio of friction layer material, structural layer material and friction layer material is 1:5:1. The mold is pressed under a pressure of 40MPa to obtain the green structure.

[0404] d. The green structure was sintered in air at 1300℃ for 2 hours to obtain the sintered green material.

[0405] e. Preheat the sintered billet to 850°C, preheat the pressure infiltration mold to 500°C, and heat the A356 aluminum alloy liquid to 750°C.

[0406] f. Place the preheated sintered billet into the pressure infiltration mold, pour molten aluminum into the mold, press it under a pressure of 120MPa, and after the molten aluminum alloy has completely solidified, demold it, remove surface defects, and perform T7 heat treatment to obtain the brake disc.

[0407] Example 17

[0408] In this embodiment, the components of the structural layer raw material include: 74% silicon carbide, 8% alumina, 2% stearic acid dispersant, and 16% PMMA; the silicon carbide has a particle size of 5 μm, the alumina is γ-Al2O3, and the alumina has a particle size of 0.5 μm.

[0409] The components of the friction layer raw material include: 54% silicon carbide with a particle size of 100μm, 40% silicon carbide with a particle size of 20μm, 4% alumina, and 2% stearic acid dispersant.

[0410] a. Add silicon carbide, alumina, stearic acid dispersant and PMMA to anhydrous ethanol and disperse evenly, then dynamically dry at 60℃ to obtain the structural layer raw material.

[0411] b. Add silicon carbide, alumina and stearic acid dispersant to anhydrous ethanol and disperse evenly, then dynamically dry at 60°C to obtain the friction layer raw material.

[0412] c. The structural layer material and the friction layer material are filled into the mold. The friction layer material, structural layer material and friction layer material are laid in the mold in sequence. Here, the mass ratio of friction layer material, structural layer material and friction layer material is 1:5:1. The mold is pressed under a pressure of 40MPa to obtain the green structure.

[0413] d. The green structure was sintered in air at 1300℃ for 2 hours to obtain the sintered green material.

[0414] e. Preheat the sintered billet to 850°C, preheat the pressure infiltration mold to 500°C, and heat the A356 aluminum alloy liquid to 750°C.

[0415] f. Place the preheated sintered billet into the pressure infiltration mold, pour molten aluminum into the mold, press it under a pressure of 120MPa, and after the molten aluminum alloy has completely solidified, demold it, remove surface defects, and perform T7 heat treatment to obtain the brake disc.

[0416] Example 18

[0417] In this embodiment, the components of the structural layer raw material include: 64% silicon carbide, 10% alumina, 2% stearic acid dispersant, and 24% PMMA; the silicon carbide has a particle size of 5 μm, the alumina is γ-Al2O3, and the alumina has a particle size of 0.5 μm.

[0418] The components of the friction layer raw material include: 54% silicon carbide with a particle size of 100μm, 40% silicon carbide with a particle size of 20μm, 4% alumina, and 2% stearic acid dispersant.

[0419] a. Add silicon carbide, alumina, stearic acid dispersant and PMMA to anhydrous ethanol and disperse evenly, then dynamically dry at 60℃ to obtain the structural layer raw material.

[0420] b. Add silicon carbide, alumina and stearic acid dispersant to anhydrous ethanol and disperse evenly, then dynamically dry at 60°C to obtain the friction layer raw material.

[0421] c. The structural layer material and the friction layer material are filled into the mold. The friction layer material, structural layer material and friction layer material are laid in the mold in sequence. Here, the mass ratio of friction layer material, structural layer material and friction layer material is 1:5:1. The mold is pressed under a pressure of 40MPa to obtain the green structure.

[0422] d. The green structure was sintered in air at 1300℃ for 2 hours to obtain the sintered green material.

[0423] e. Preheat the sintered billet to 850°C, preheat the pressure infiltration mold to 500°C, and heat the A356 aluminum alloy liquid to 750°C.

[0424] f. Place the preheated sintered billet into the pressure infiltration mold, pour molten aluminum into the mold, press it under a pressure of 120MPa, and after the molten aluminum alloy has completely solidified, demold it, remove surface defects, and perform T7 heat treatment to obtain the brake disc.

[0425] Example 19

[0426] In this embodiment, the components of the structural layer raw material include: 68% silicon carbide, 6% alumina, 2% stearic acid dispersant, and 24% PMMA; the silicon carbide has a particle size of 5 μm, the alumina is γ-Al2O3, and the alumina has a particle size of 0.5 μm.

[0427] The components of the friction layer raw material include: 54% silicon carbide with a particle size of 100μm, 40% silicon carbide with a particle size of 20μm, 4% alumina, and 2% stearic acid dispersant.

[0428] a. Add silicon carbide, alumina, stearic acid dispersant and PMMA to anhydrous ethanol and disperse evenly, then dynamically dry at 60℃ to obtain the structural layer raw material.

[0429] b. Add silicon carbide, alumina and stearic acid dispersant to anhydrous ethanol and disperse evenly, then dynamically dry at 60°C to obtain the friction layer raw material.

[0430] c. The structural layer material and the friction layer material are filled into the mold. The friction layer material, structural layer material and friction layer material are laid in the mold in sequence. Here, the mass ratio of friction layer material, structural layer material and friction layer material is 1:5:1. The mold is pressed under a pressure of 40MPa to obtain the green structure.

[0431] d. The green structure was sintered in air at 1500℃ for 2 hours to obtain the sintered green body.

[0432] e. Preheat the sintered billet to 850°C, preheat the pressure infiltration mold to 500°C, and heat the A356 aluminum alloy liquid to 750°C.

[0433] f. Place the preheated sintered billet into the pressure infiltration mold, pour molten aluminum into the mold, press it under a pressure of 120MPa, and after the molten aluminum alloy has completely solidified, demold it, remove surface defects, and perform T7 heat treatment to obtain the brake disc.

[0434] Example 20

[0435] In this embodiment, the components of the structural layer raw material include: 68% silicon carbide, 6% alumina, 2% stearic acid dispersant, and 24% PMMA; the silicon carbide has a particle size of 5 μm, the alumina is γ-Al2O3, and the alumina has a particle size of 0.5 μm.

[0436] The components of the friction layer raw material include: 76% silicon carbide with a particle size of 100μm, 20% silicon carbide with a particle size of 20μm, 2% alumina, and 2% stearic acid dispersant.

[0437] a. Add silicon carbide, alumina, stearic acid dispersant and PMMA to anhydrous ethanol and disperse evenly, then dynamically dry at 60℃ to obtain the structural layer raw material.

[0438] b. Add silicon carbide, alumina and stearic acid dispersant to anhydrous ethanol and disperse evenly, then dynamically dry at 60°C to obtain the friction layer raw material.

[0439] c. The structural layer material and the friction layer material are filled into the mold. The friction layer material, structural layer material and friction layer material are laid in the mold in sequence. Here, the mass ratio of friction layer material, structural layer material and friction layer material is 1:5:1. The mold is pressed under a pressure of 40MPa to obtain the green structure.

[0440] d. The green structure was sintered in air at 1500℃ for 2 hours to obtain the sintered green body.

[0441] e. Preheat the sintered billet to 850°C, preheat the pressure infiltration mold to 500°C, and heat the A356 aluminum alloy liquid to 750°C.

[0442] f. Place the preheated sintered billet into the pressure infiltration mold, pour molten aluminum into the mold, press it under a pressure of 120MPa, and after the molten aluminum alloy has completely solidified, demold it, remove surface defects, and perform T7 heat treatment to obtain the brake disc.

[0443] Example 21

[0444] In this embodiment, the components of the structural layer raw material include: 54% silicon carbide, 20% alumina, 2% stearic acid dispersant, and 24% PMMA; the silicon carbide has a particle size of 5 μm, the alumina is γ-Al2O3, and the alumina has a particle size of 0.5 μm.

[0445] The components of the friction layer raw material include: 54% silicon carbide with a particle size of 100μm, 40% silicon carbide with a particle size of 20μm, 4% alumina, and 2% stearic acid dispersant.

[0446] a. Add silicon carbide, alumina, stearic acid dispersant and PMMA to anhydrous ethanol and disperse evenly, then dynamically dry at 60℃ to obtain the structural layer raw material.

[0447] b. Add silicon carbide, alumina and stearic acid dispersant to anhydrous ethanol and disperse evenly, then dynamically dry at 60°C to obtain the friction layer raw material.

[0448] c. The structural layer material and the friction layer material are filled into the mold. The friction layer material, structural layer material and friction layer material are laid in the mold in sequence. Here, the mass ratio of friction layer material, structural layer material and friction layer material is 1:5:1. The mold is pressed under a pressure of 40MPa to obtain the green structure.

[0449] d. The green structure was sintered in air at 1500℃ for 2 hours to obtain the sintered green body.

[0450] e. Preheat the sintered billet to 850°C, preheat the pressure infiltration mold to 500°C, and heat the A356 aluminum alloy liquid to 750°C.

[0451] f. Place the preheated sintered billet into the pressure infiltration mold, pour molten aluminum into the mold, press it under a pressure of 120MPa, and after the molten aluminum alloy has completely solidified, demold it, remove surface defects, and perform T7 heat treatment to obtain the brake disc.

[0452] Comparative Example 5

[0453] In this comparative example, the components of the structural layer raw material include: 40% silicon carbide, 2% stearic acid dispersant, and 58% aluminum alloy powder; the particle size of silicon carbide is 5μm, the aluminum alloy is A356, and the powder particle size is 5μm.

[0454] The components of the friction layer raw material include: 58% silicon carbide with a particle size of 100μm, 20% silicon carbide with a particle size of 20μm, 20% A356 aluminum alloy powder (20μm), and 2% stearic acid dispersant.

[0455] a. Add 5μm silicon carbide, 5μm aluminum alloy powder, and stearic acid dispersant to anhydrous ethanol and disperse evenly, then dynamically dry at 60℃ to obtain the structural layer raw material.

[0456] b. Disperse 100μm / 20μm silicon carbide powder, 20μm aluminum alloy powder and stearic acid dispersant in anhydrous ethanol until uniform, and then dynamically dry at 60℃ to obtain the friction layer raw material.

[0457] c. The structural layer material and the friction layer material are filled into the mold. The friction layer material, structural layer material and friction layer material are laid in the mold in sequence. Here, the mass ratio of friction layer material, structural layer material and friction layer material is 1:5:1. The mold is pressed under a pressure of 100MPa to obtain the green structure.

[0458] d. The green structure was hot-pressed and sintered in a vacuum atmosphere at 560℃ and 30MPa for 2 hours to obtain the sintered green body.

[0459] e. Demolding, removing surface defects, and performing T7 heat treatment to obtain the brake disc.

[0460] Figure 11 is an electron microscope image of the sintered blank in Example 16. As shown in Figure 11, the sintered blank includes a first porous ceramic framework and a second porous ceramic framework formed by sintering. The electron microscope image shows that it has a porous structure.

[0461] The brake discs obtained in Examples 16-21 were subjected to porosity and four-point bending strength tests, and the volume percentages of mullite and aluminum alloy in the structural and friction layers were also tested. Porosity testing was performed according to the methods in GB / T 3810.3 and GB / T 25995; four-point bending strength testing was performed according to GB / T The methods in ISO 6569-86 and ISO 14704-2000 were followed, with test specimens measuring 35mm × 3mm × 4mm. The coefficient of friction was tested using an MM3000 friction and wear inertia test bench. The volume percentage of mullite in the structural and friction layers was determined using SEM-BSD surface scan composition analysis. The volume percentage of mullite in the sintered first and second porous ceramic skeletons was analyzed using SEM-BSD surface scan composition analysis. Based on the volume percentage of the first porous ceramic skeleton in the structural layer and the second porous ceramic skeleton in the friction layer, the volume percentage of mullite in the first porous ceramic skeleton and the volume percentage of mullite in the friction layer were calculated. Aluminum alloy filled the pores of the first and second porous ceramic skeletons in both the structural and friction layers. The volume percentage of aluminum alloy in the structural layer was the same as the porosity of the first porous ceramic skeleton, and the volume percentage of aluminum alloy in the friction layer was the same as the porosity of the second porous ceramic skeleton. The test results are shown in Table 3.

[0462] Table 3 Comparison of test results for different embodiments and comparative examples

[0463] As shown in Table 3, the friction coefficients of the brake discs obtained in some embodiments of this disclosure are all stable within the range of [0.40, 0.45], and the four-point bending strength of the brake discs at 300℃ is greater than 230MPa, exhibiting stable friction coefficients and structural strength. In the brake disc of Comparative Example 5, although the aluminum alloy content in the structural layer is 60% and the aluminum alloy content in the friction layer is 20%, the use of a method of mixing all raw materials and then pressing and sintering without first forming a porous ceramic skeleton results in poor bending strength, low friction coefficient, and significant performance degradation at high temperatures, affecting the overall performance of the brake disc.

[0464] The brake discs of some embodiments disclosed herein, by embedding aluminum-based materials in a porous ceramic skeleton, can significantly improve the bending strength and friction coefficient of the brake discs, and can ensure the performance of the brake discs at high temperatures.

[0465] Furthermore, calculations show that in Examples 16-19, the mullite volume ratio V3 and the aluminum alloy volume ratio V4 in the structural layer satisfy the formula V3 = -0.5V4. 2 To meet the requirement of +0.5V4+k, the volume percentage of mullite in the friction layer (V5) and the volume percentage of aluminum alloy in the friction layer (V6) must satisfy V5 = -0.5V6. 2 The requirement is +0.5V6+k.

[0466] In Example 20, the volume percentage V5 of mullite in the friction layer and the volume percentage V6 of aluminum alloy in the friction layer cannot satisfy the formula V5 = -0.5V6. 2 +0.5V6+k.

[0467] A comparison between Examples 19 and 20 reveals that the porosity in Example 20 reached 30%. This is because the amount of mullite generated during sintering was relatively small, resulting in more pores in the second porous ceramic skeleton. Furthermore, the low mullite content led to a decrease in the structural strength of the friction layer, which in turn resulted in a decrease in the friction coefficient and poor stability of the friction coefficient.

[0468] In Example 21, the volume percentage V3 of mullite in the structural layer and the volume percentage V4 of aluminum alloy in the structural layer cannot satisfy the formula V3 = -0.5V4. 2 The requirement is +0.5V4+k.

[0469] A comparison of Examples 19 and 21 reveals that, with the same proportion of pore-forming agent added, the porosity of the first ceramic skeleton in Example 21 is lower, resulting in higher strength of the sintered blank, but a poorer coefficient of friction for the brake disc. This is mainly because the structural layer material in Example 21 contains a larger amount of alumina, leading to the formation of more mullite. This, in turn, causes volume shrinkage during the sintering of the first and second porous ceramic skeletons, reducing their porosity. Furthermore, the excessively high volumetric proportion of mullite can also lead to a decrease in the thermal conductivity of the structural layer, resulting in slower surface heat transfer during brake disc friction and reduced frictional stability.

[0470] In the description of this specification, exemplary features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0471] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

A braking assembly, comprising: (1) The connecting component (3) is connected to the disc cap (1); and The elastic element (4) includes a radial floating part (41); the radial floating part (41) is disposed between the disc cap (1) and the connecting assembly (3) along the radial direction of the disc cap (1), and is elastically deformable along the radial direction of the disc cap (1). The braking assembly according to claim 1, wherein, The elastic deformation of the radial floating part (41) along the radial direction of the disc cap (1) is greater than or equal to 0.05 mm and less than or equal to 0.9 mm. The braking assembly according to claim 1 or 2, wherein, The radial floating part (41) includes at least one elastic part that is elastically deformable along the radial direction of the disc cap (1). The braking assembly according to claim 3, wherein, The elastic part can elastically deform in the radial direction away from the center of the disc cap (1); or, The elastic part can be elastically deformed along the radial direction of the disc cap (1) toward the center of the disc cap (1). The braking assembly according to claim 3 or 4, wherein, The elastic portion includes a curved section that arches toward the center of the cap (1), so that the elastic portion can elastically deform in the radial direction away from the center of the cap (1); or, The curved section arches away from the center of the cap (1) so that the elastic part can be elastically deformed in the radial direction of the cap (1) toward the center of the cap (1). The braking assembly according to claim 3 or 4, wherein, The radial floating part (41) includes at least one first elastic part (411) and at least one second elastic part (412) arranged alternately in sequence along the circumference of the cap (1); The first elastic part (411) includes a first curved section that arches toward the center of the disc cap (1); The second elastic part (412) includes a second curved section that arches toward the center of the cap (1). The braking assembly according to claim 6, wherein, The at least one first elastic part (411) includes two first elastic parts (411), and the at least one second elastic part (412) includes one second elastic part (412); Along the circumference of the cap (1), the second elastic part (412) is located between the two first elastic parts (411). The braking assembly according to claim 6 or 7, wherein, The first curved segment and the second curved segment have arc-shaped, crest-shaped, Λ-shaped, Ω-shaped, and П-shaped shapes in the first cross section; The first cross section is perpendicular to the axial direction of the disc cap (1). The braking assembly according to any one of claims 6 to 8, wherein, The elastic element (4) also includes two connecting parts (42); The two connecting parts (42) are arranged at circumferential intervals along the disc cap (1), and the radial floating part (41) is connected between the two connecting parts (42) at one end facing the center of the disc cap (1); Each of the two connecting parts (42) is provided with at least one axially floating part (43), which is disposed between the disc cap (1) and the connecting assembly (3) and is elastically deformable along the axial direction of the disc cap (1). The braking assembly according to claim 9, wherein, The at least one axial floating part (43) includes two axial floating parts (43), which are respectively connected to the two ends of the connecting part (42) in the axial direction of the cap (1). The braking assembly according to claim 9 or 10, wherein, The thickness of either of the two axial floating parts (43) is greater than or equal to 0.4 mm and less than or equal to 0.8 mm. The braking assembly according to any one of claims 9 to 11, wherein, The end of the connecting part (42) facing the center of the disc cap (1) is the first end (D1); The end of the connecting part (42) opposite to the center of the cap (1) is the second end (D2); Along the radial direction of the cap (1), the shortest distance from the second curved segment to the second end (D2) is the first distance (w1), and the maximum distance from the first curved segment to the first end (D1) is the second distance (w2); The ratio of the first distance (w1) to the second distance (w2) is greater than or equal to 3.72 and less than or equal to 22.

54. The braking assembly according to any one of claims 9 to 12, wherein, The two connecting parts (42) are provided with a first limiting part (44) on their surfaces that are far apart from each other; The first limiting part (44) is configured to cooperate with the disc cap (1) to prevent the elastic member (4) from separating from the disc cap (1) radially. The braking assembly according to claim 13, wherein, The first limiting part (44) is a limiting protrusion. The braking assembly according to claim 14, wherein, The protrusion height of the first limiting part (44) is the first height (h), and the length of the connecting part (42) along the circumferential direction of the disc cap (1) is the first length (a); The ratio of the first height (h) to the first length (a) is greater than or equal to 1 / 6 and less than or equal to 1 / 3. The braking assembly according to any one of claims 10 to 15, wherein, The two axial floating parts (43) are provided with second limiting parts (45) on their surfaces facing each other; The second limiting part (45) is configured to cooperate with the disc cap (1) to prevent the elastic member (4) from separating from the disc cap (1) radially. The braking assembly according to claim 16, wherein, The second limiting part (45) is a limiting protrusion. The braking assembly according to claim 17, wherein, The protrusion height of the second limiting part (45) is the second height; The distance between the two axial floating parts (43) is the third distance, and the ratio of the second height to the third distance is greater than or equal to 1 / 6 and less than or equal to 1 / 3. The braking assembly according to any one of claims 1 to 18, wherein, The radial floating part (41) is located on the side of the connecting assembly (3) facing the center of the disc cap (1). The braking assembly according to claim 19, wherein, The disc cap (1) is provided with a mounting hole (11), and the connecting component (3) passes through the mounting hole (11); The radial floating part (41) is located between the edge of the mounting hole (11) near the center of the disc cap (1) and the connecting assembly (3). The braking assembly according to any one of claims 1 to 20, wherein, The elastic element (4) includes at least one of steel elastic elements, iron elastic elements, aluminum alloy elastic elements and ceramic elastic elements. A brake disc (202) includes: The braking assembly according to any one of claims 1 to 21; and Brake disc (2); the brake disc (2) is connected to the connecting component (3) of the brake assembly. A wheel (20) includes: Wheel hub (201); and According to claim 22, the brake disc (202) has a disc cap (1) fixed to the wheel hub (201) and arranged coaxially with the wheel hub (201). A vehicle (100) comprising: Body (10); and The wheel (20) according to claim 23 is connected to the vehicle body (10).

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