Composite layer, noise reduction structure, brake pad and method for manufacturing same, brake disc and vehicle

Abstract

Embodiments of this application provide a composite layer, a noise reduction structure, a brake pad and its preparation method, a brake disc, and a vehicle. The composite layer includes an organic elastic material for adjusting the natural frequency of the composite layer in a first temperature range and an inorganic elastic material for adjusting the natural frequency of the composite layer in a second temperature range. The organic elastic material can adjust the natural frequency of the composite layer in the first temperature range, thus avoiding the natural frequency range of the brake disc. At higher temperatures, the organic elastic material is prone to failure. Adding an inorganic elastic material to the organic elastic material allows the inorganic elastic material to adjust the natural frequency of the composite layer in the second temperature range, helping to maintain the relative stability of the natural frequency of the composite layer under different temperature environments, thereby reducing brake noise.

Description

Technical Field

[0001] This application relates to the technical field of automotive braking, and more particularly to a composite layer, a noise reduction structure, brake pads and their preparation methods, brake discs and vehicles. Background Technology

[0002] In automotive braking systems, the performance of brake pads directly affects braking safety, comfort, and noise levels.

[0003] In related technologies, brake pads typically include organic elastic materials, which can suppress the transmission of vibration energy and help avoid the natural frequency of the brake disc, thereby reducing noise caused by resonance.

[0004] However, if the brake pads are used at high temperatures, the organic elastic material may decompose, causing a significant change in the natural frequency and triggering resonance, resulting in harsh noise. Summary of the Invention

[0005] This application provides a composite layer, a noise reduction structure, a brake pad and its preparation method, a brake disc and a vehicle, which aim to improve the noise problem caused by the instability of the natural frequency due to changes in ambient temperature.

[0006] To achieve the above objectives, in a first aspect, embodiments of this application provide a composite layer, the composite layer comprising:

[0007] An organic elastic material is used to adjust the natural frequency of the composite layer in a first temperature range;

[0008] Inorganic elastic material is used to adjust the natural frequency of the composite layer in the second temperature range;

[0009] The average temperature in the first temperature range is less than the average temperature in the second temperature range.

[0010] Optionally, in some embodiments of this application, the difference between the natural frequency of the composite layer in the first temperature range and the natural frequency of the composite layer in the second temperature range is a preset threshold.

[0011] Preferably, the preset threshold value ranges from 0 to 10.

[0012] Preferably, the preset threshold value ranges from greater than or equal to 2 to less than or equal to 7.

[0013] Optionally, in some embodiments of this application, the first temperature range is greater than or equal to 0°C and less than or equal to 250°C; and / or

[0014] The second temperature range is greater than or equal to 250°C and less than or equal to 500°C.

[0015] Optionally, in some embodiments of this application, the organic elastic material includes at least one of nitrile rubber, styrene-butadiene rubber, chlorobutyl rubber, fluororubber, silicone rubber, polyurethane elastomer, or polyolefin elastomer.

[0016] Optionally, in some embodiments of this application, the composite layer further includes an adhesive material;

[0017] Preferably, the bonding material comprises modified phenolic resin and / or unmodified phenolic resin.

[0018] Optionally, in some embodiments of this application, the modified phenolic resin includes at least one of nitrile-modified phenolic resin, cashew nut shell oil-modified phenolic resin, melamine-modified phenolic resin, molybdenum-modified phenolic resin, and boron-modified phenolic resin.

[0019] Optionally, in some embodiments of this application, the inorganic elastic material includes an expandable material and / or an expandable material;

[0020] Preferably, the expandable material includes at least one of expandable graphite, expandable vermiculite, and expandable quartz;

[0021] Preferably, the expanded material includes at least one of expanded graphite and expanded vermiculite.

[0022] Optionally, in some embodiments of this application, the mass ratio of the organic elastic material to the inorganic elastic material is greater than 1.5.

[0023] Preferably, the mass ratio of the organic elastic material to the inorganic elastic material ranges from 1.66 to 8.

[0024] Optionally, in some embodiments of this application, the organic elastic material comprises 50% to 80% by mass in the composite layer; and / or

[0025] The inorganic elastic material in the composite layer comprises 10% to 30% by mass; and / or

[0026] The adhesive material comprises 10% to 20% by mass in the composite layer.

[0027] Secondly, embodiments of this application provide a noise reduction structure, which includes the composite layer as described above.

[0028] Thirdly, embodiments of this application provide a brake pad, the brake pad comprising:

[0029] Back panel:

[0030] A friction layer is disposed on one side of the back plate; and

[0031] As described above, the composite layer is disposed between the back plate and the friction layer; and / or

[0032] The composite layer is disposed on the side of the back plate opposite to the friction layer.

[0033] Optionally, in some embodiments of this application, the brake pad includes two composite layers, wherein one composite layer is disposed between the backing plate and the friction layer, and the other composite layer is disposed on the side of the backing plate opposite to the friction layer; and / or

[0034] The projected area of ​​the composite layer on the back plate is greater than or equal to the area of ​​the back plate.

[0035] Optionally, in some embodiments of this application, the thickness of the composite layer is 0.1 mm to 0.5 mm;

[0036] Preferably, the thickness of the composite layer is 0.25 mm to 0.5 mm.

[0037] Optionally, in some embodiments of this application, the thickness of the back plate is 5 mm to 6 mm;

[0038] Preferably, the thickness of the back plate is 5 mm to 5.5 mm.

[0039] Optionally, in some embodiments of this application, the noise generation rate of the brake pads ranges from 5.1% to 7.2%; and / or

[0040] The difference between the natural frequency of the brake pad in the first temperature range and the natural frequency of the brake pad in the second temperature range is 0 Hz to 10 Hz; and / or

[0041] The difference between the elastic modulus of the brake pad in the first temperature range and the elastic modulus of the brake pad in the second temperature range is 0 GPa to 0.6 GPa; and / or

[0042] The difference between the natural frequency of the brake pad and the natural frequency of the brake disc is greater than or equal to 20.

[0043] Fourthly, embodiments of this application provide a method for preparing a brake pad, the method comprising the following steps:

[0044] The raw materials of the composite layer, the back plate, and the friction layer are stacked in a preset order and then hot-pressed to obtain a preform.

[0045] The preformed blank is then cured to obtain the brake pad.

[0046] Optionally, in some embodiments of this application, the hot pressing temperature is 150°C to 170°C; and / or

[0047] The hot pressing pressure is 20 MPa to 40 MPa; and / or

[0048] The curing temperature is 200°C to 250°C; and / or

[0049] The preset order includes sorting by the raw materials of the composite layer, the back plate, and the friction layer, or sorting by the raw materials of the composite layer, the back plate, the composite layer, and the friction layer, or sorting by the raw materials of the back plate, the composite layer, and the friction layer.

[0050] In a sixth aspect, embodiments of this application provide a brake disc, the brake disc comprising the brake pads as described above, or the composite layer as described above, or the noise reduction structure as described in claim 10.

[0051] In a seventh aspect, embodiments of this application provide a vehicle, the vehicle including the brake disc as described above, the composite layer as described above, the noise reduction structure as described above, or the brake pads as described above.

[0052] This application provides a composite layer, a noise reduction structure, a brake pad and its preparation method, a brake disc, and a vehicle. The composite layer includes an organic elastic material and an inorganic elastic material. The organic elastic material can adjust the natural frequency of the composite layer in a first temperature range, thus avoiding the natural frequency range of the brake disc. At higher temperatures, the organic elastic material is prone to failure. Adding an inorganic elastic material to the organic elastic material allows the inorganic elastic material to adjust the natural frequency of the composite layer in a second temperature range, helping to maintain the relative stability of the natural frequency of the composite layer under different temperature environments, thereby reducing brake noise. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram showing the inherent frequencies of the composite layer on one side of the backplate and on both sides of the backplate in some embodiments of this application.

[0055] Figure 2 This is an exploded structural diagram of a noise reduction structure according to some embodiments of this application;

[0056] Figure 3This is an exploded structural diagram of another noise reduction structure in some embodiments of this application;

[0057] Figure 4 This is a schematic diagram of the brake pad structure in some embodiments of this application;

[0058] Figure 5 This is a flowchart of a method for preparing brake pads in some embodiments of this application;

[0059] In the picture,

[0060] 100, Brake pad; 110, Backing plate; 120, Composite layer; 200, Friction layer. Detailed Implementation

[0061] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0062] This application provides a composite layer, a noise reduction structure, a brake pad and its preparation method, a brake disc and a vehicle, which aim to improve the noise problem caused by the decrease in natural frequency due to changes in ambient temperature.

[0063] In a first aspect, this application provides a composite layer comprising:

[0064] Organic elastic materials are used to adjust the natural frequency of the composite layer in a first temperature range;

[0065] Inorganic elastic materials are used to adjust the natural frequency of the composite layer in the second temperature range;

[0066] The average temperature in the first temperature range is lower than the average temperature in the second temperature range.

[0067] By adopting the above scheme, the organic elastic material can adjust the natural frequency of the composite layer in the first temperature range, thus avoiding the natural frequency range of the brake disc. At higher temperatures, the organic elastic material is prone to failure. Adding inorganic elastic material to the organic elastic material allows the inorganic elastic material to adjust the natural frequency of the composite layer in the second temperature range, helping to maintain the relative stability of the natural frequency of the composite layer under different temperature environments, thereby reducing braking noise.

[0068] It should be noted that the natural frequency is defined as the frequency at which a structure / system vibrates naturally when subjected to external excitation.

[0069] Any continuous structure can be considered as an infinite number of infinitesimal rigid bodies, meaning that during vibration, it is equivalent to the vibration of multiple infinitesimal rigid bodies. (Reference) Figure 1 Figure 10 shows the natural frequency diagram of the noise reduction structure positioned on one side of the back panel; Figure 20 shows the natural frequency diagram of the noise reduction structure positioned on the other side of the back panel; and Figure 30 shows the natural frequency diagram of the noise reduction structure positioned on both sides of the back panel. Figure 1 The diagram illustrates three different micro-rigid body vibration modes that generate different natural frequencies. The natural frequency F is a fixed property of the structure, related to its mass m, stiffness k, and damping ratio ξ, as shown in the following formula:

[0070]

[0071] In some embodiments of this application, the difference between the natural frequency of the composite layer in a first temperature range and the natural frequency of the composite layer in a second temperature range is a preset threshold value.

[0072] By adopting the above scheme, since the organic elastic material is used to adjust the natural frequency of the composite layer in the first temperature range and the inorganic elastic material is used to adjust the natural frequency of the composite layer in the second temperature range, the difference between the natural frequency of the composite layer in the first temperature range and the natural frequency of the composite layer in the second temperature range can be adjusted by limiting the preset threshold, so as to prevent the composite layer from generating harsh noise due to the instability of its natural frequency under different temperature environments.

[0073] In some embodiments of this application, the preset threshold is greater than or equal to 0 and less than or equal to 10. Further, the preset threshold is greater than or equal to 2 and less than or equal to 7. Exemplarily, the preset threshold can be 2, 3, 4, 5, 6, 7, or any value between two adjacent values ​​mentioned above.

[0074] By adopting the above scheme, the smaller the preset threshold, the closer the natural frequency of the composite layer in the first temperature range is to the natural frequency of the composite layer in the second temperature range. This is beneficial for the composite layer to maintain a stable natural frequency in different temperature ranges, thereby achieving noise reduction. Conversely, the larger the preset threshold, the more unstable the natural frequency of the composite layer is in different temperature ranges. This will cause the natural frequency to fall into the natural frequency range of the brake disc due to different temperatures, resulting in resonance.

[0075] In some embodiments of this application, the first temperature range can be greater than or equal to 0°C and less than or equal to 250°C. Further, the first temperature range can be greater than or equal to 25°C and less than or equal to 200°C.

[0076] It is understood that the first temperature range can be understood as the working temperature of most organic elastic materials, so the first temperature range should not be too high. In this embodiment, the first temperature range is set to be greater than or equal to 0°C and less than or equal to 250°C.

[0077] In some embodiments of this application, the second temperature range can be greater than or equal to 250°C and less than or equal to 500°C. Further, the second temperature range can be greater than or equal to 300°C and less than or equal to 500°C.

[0078] It is understandable that the second temperature range can be interpreted as the temperature at which inorganic elastic materials absorb heat and expand to reduce their elastic modulus. Therefore, the second temperature range is set to be greater than or equal to 250°C and less than or equal to 500°C.

[0079] In some embodiments of this application, the organic elastic material may include at least one of nitrile rubber, styrene-butadiene rubber, chlorobutyl rubber, fluororubber, silicone rubber, polyurethane elastomer or polyolefin elastomer.

[0080] By adopting the above-mentioned scheme, the above-mentioned materials have high resilience at room temperature to medium temperature, which can suppress the transmission of vibration energy and help to avoid the natural frequency range of the brake disc.

[0081] In some embodiments of this application, the inorganic elastic material may include an expandable material and / or an expandable material.

[0082] It is understandable that expandable materials refer to materials that are already in an expanded state, or materials that are directly prepared into an expanded structure through specific processes. The expansion process of such materials is complete, the structure is stable, and it no longer changes significantly due to changes in external conditions.

[0083] Expandable materials are materials that can expand in volume under specific conditions (such as heating, light exposure, chemical reaction, etc.), but remain in their original state, i.e., without expansion, before the conditions are triggered.

[0084] In some embodiments of this application, the expandable material may include at least one of expandable graphite, expandable vermiculite, and expandable quartz.

[0085] By adopting the above scheme, expandable graphite, expandable vermiculite, and expandable quartz can all expand and produce adsorption under braking high temperature. After expansion, they will fill the internal pores and interface defects of the composite layer, which helps to suppress crack propagation and reduce vibration transmission path. Moreover, the mutual friction between the expanded particles and the interface slip with the organic elastic material will dissipate vibration energy and suppress high-frequency noise.

[0086] Expandable graphite possesses good thermal stability and expandability. After expanding at high temperatures, it can fill the voids in the material, increasing the density of the composite layer and thus improving the damping effect. Furthermore, expandable graphite also has a heat-absorbing effect after expansion, which helps absorb heat under high-temperature braking conditions. In addition, expandable graphite also has a certain degree of lubrication, which helps reduce frictional noise.

[0087] Expandable vermiculite can expand at high temperatures to form a multi-layered structure, which has good heat insulation and sound absorption properties, and helps to maintain the stability and noise reduction effect of the composite layer in high-temperature environments.

[0088] Expandable quartz expands at high temperatures, which can increase the hardness and wear resistance of the composite layer; moreover, the expansion property helps to adjust the microstructure of the composite layer and optimize the damping performance at high temperatures.

[0089] In some embodiments of this application, the expanded material includes at least one of expanded graphite and expanded vermiculite.

[0090] By employing the above method, expanded graphite is a loose, porous, worm-like material obtained from natural graphite flakes through intercalation, washing, drying, and high-temperature expansion. Expanded graphite exhibits good high-temperature resistance and is suitable for high-temperature environments, providing excellent softness, compression resilience, and adsorption properties.

[0091] Expanded vermiculite is formed by high-temperature calcination of vermiculite. Expanded graphite has good high-temperature resistance and is suitable for high-temperature environments, where it can provide excellent compression resilience and other properties.

[0092] In some embodiments of this application, the composite layer may further include an adhesive material, which may include modified phenolic resin or unmodified phenolic resin.

[0093] It is understandable that adhesive materials are used to bond organic and inorganic elastic materials to form an interpenetrating network structure, thereby improving the bonding strength of the composite layer. At the same time, the elastic buffer of organic elastic materials and the expansion stress of inorganic elastic materials can prevent the composite layer from delaminating at high temperatures.

[0094] In some embodiments of this application, the modified phenolic resin may include at least one of nitrile-modified phenolic resin, cashew nut shell oil-modified phenolic resin, melamine-modified phenolic resin, molybdenum-modified phenolic resin, and boron-modified phenolic resin.

[0095] By adopting the above schemes, the modified phenolic resins mentioned above have high bonding strength, which helps to firmly bond organic elastic materials and inorganic elastic materials; at the same time, the heat resistance of phenolic resins helps to maintain good bonding performance in a high temperature range and avoid delamination or failure at high temperatures.

[0096] In addition to basic bonding properties, nitrile-modified phenolic resin exhibits good flexibility, which helps improve the composite layer's resistance to cracking under vibration and impact; cashew nutshell oil-modified phenolic resin has good ductility and also enhances its resistance to water vapor erosion; melamine-modified phenolic resin has high heat resistance, making it suitable for high-temperature operating conditions with frequent braking, and helps reduce the risk of combustion in the composite layer; molybdenum-modified phenolic resin has high hardness, which helps reduce wear on the composite layer during friction, thereby extending its service life; moreover, molybdenum modification helps to disperse localized high temperatures and reduce thermal stress concentration; boron-modified phenolic resin, compared to unmodified phenolic resin, helps to form a denser oxide layer, preventing oxygen penetration at high temperatures, thereby delaying the aging of the composite layer.

[0097] In some embodiments of this application, the mass ratio of organic elastic material to inorganic elastic material ranges from 1.5. Further, the mass ratio of organic elastic material to inorganic elastic material ranges from 1.66 to 8. Exemplarily, the mass ratio of organic elastic material to inorganic elastic material is 1.66, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, or any value between two adjacent values.

[0098] By adopting the above scheme, the higher the proportion of organic elastic material in the composite layer, the better it is to provide excellent resilience, absorb vibration energy during braking in the first temperature range, and reduce low-frequency noise; the inorganic elastic material expands in the second temperature range to form a porous structure, which helps to enhance damping characteristics.

[0099] In addition, the mass ratio also affects the stiffness of the composite layer. If the proportion of organic elastic material is high and the elastic modulus is low, the natural frequency of the composite layer will be increased. On the other hand, if the proportion of inorganic elastic material increases and the elastic modulus increases, the natural frequency of the composite layer can be reduced, which may cause noise in high-frequency environments.

[0100] In some embodiments of this application, the mass percentage of the organic elastic material in the composite layer is 50% to 80%. Exemplarily, the mass percentage of the organic elastic material can be 50%, 52%, 55%, 58%, 60%, 63%, 65%, 68%, 70%, 72%, 75%, 77%, 80%, and any value between two adjacent values.

[0101] In some embodiments of this application, the mass percentage of inorganic elastic material in the composite layer can be from 10% to 30%. Exemplarily, the mass percentage of inorganic elastic material can be 10%, 12%, 15%, 18%, 20%, 23%, 25%, 28%, 30%, or any value between two adjacent values.

[0102] In some embodiments of this application, the mass percentage of the adhesive material in the composite layer can be from 10% to 20%. Exemplarily, the mass percentage of the adhesive material can be 10%, 12%, 14%, 16%, 18%, 20%, or any value between two adjacent values.

[0103] By adopting the above scheme, the addition ratio of organic elastic material is between 50% and 80%, which helps to absorb vibration energy under the working conditions of the first temperature range, thereby reducing cold braking noise; the addition ratio of inorganic elastic material is between 10% and 30%, which helps to expand at high temperature to form a porous structure, thereby enhancing damping performance; the addition ratio of binder material is between 10% and 20%, which is beneficial to improve the bonding performance between organic elastic material and inorganic elastic material.

[0104] According to a second aspect of this application, a method for preparing a composite layer is provided, the method comprising the following steps:

[0105] Step S100: Mix the organic elastic material with the inorganic elastic material to obtain a mixture;

[0106] Step S200: The above mixture is hot-pressed to form a composite layer.

[0107] In some embodiments of this application, in step S100, a binder material may be added during the mixing process to obtain a mixture.

[0108] In some embodiments of this application, in step S100, mixing may include, but is not limited to, at least one of mechanical stirring, ball milling, and vibration mixing.

[0109] By adopting the above scheme and combining at least one of the above methods, it is beneficial to achieve uniform blending of the raw materials.

[0110] In some embodiments of this application, the temperature of hot pressing in step S200 is not limited here; a composite layer can be formed after hot pressing.

[0111] It should be noted that in step S200, hot pressing molding includes, but is not limited to, hot pressing molding, and other molding methods can also be used to form the composite layer.

[0112] According to a third aspect of this application, a noise reduction structure is provided, which may include a composite layer as described in the first aspect above.

[0113] By adopting the above scheme, since the composite layer has the characteristic of stable inherent frequency at different temperatures, the noise reduction structure made by the above composite layer also has the characteristic of stable inherent frequency at different temperatures.

[0114] It is understandable that the noise reduction structure can be a multi-layered structure consisting of the aforementioned composite layer and other carrier structures or functional structures.

[0115] refer to Figure 2 A noise reduction structure is disclosed, comprising:

[0116] Back panel 110;

[0117] Composite layer 120 is disposed on both sides of back plate 110.

[0118] Reference Figure 3 Another noise reduction structure was disclosed, including:

[0119] Back panel 110;

[0120] Composite layer 120 is disposed on one side of back plate 110.

[0121] According to a fourth aspect of this application, a brake pad is provided, which may include:

[0122] Back panel:

[0123] A friction layer is disposed on one side of the back plate; and

[0124] A composite layer may be disposed between the backing plate and the friction layer; and / or

[0125] The composite layer is located on the side of the backplate away from the friction layer.

[0126] By adopting the above solution, the brake pad in this embodiment of the application includes a composite layer. The composite layer is used to adjust the natural frequency of the brake pad in different temperature ranges so that the brake pad, as the excitation end itself, helps to avoid the frequency range that resonates with the brake disc during braking, thereby reducing resonance noise.

[0127] It should be noted that brake pads consist of a composite layer, a backing plate, and a friction layer. With the backing plate and friction layer remaining unchanged, the natural frequency variation of the composite layer is consistent with the natural frequency variation of the brake pad.

[0128] In some embodiments of this application, the brake pad includes two composite layers, one of which is disposed between the backing plate and the friction layer, and the other composite layer is disposed on the side of the backing plate away from the friction layer.

[0129] By adopting the above scheme, composite layers are set on both sides of the back plate, which helps to provide a more uniform damping distribution, thereby suppressing noise in a wider frequency range and achieving a better noise reduction effect.

[0130] In some embodiments of this application, the projected area of ​​the composite layer on the back plate may be greater than or equal to the area of ​​the back plate.

[0131] It should be noted that the projected area refers to the projected coverage area of ​​the composite layer in the direction perpendicular to the back panel.

[0132] By adopting the above scheme, since the projected area of ​​the composite layer on the backplate is greater than or equal to the area of ​​the backplate, it helps the composite layer to fully cover the backplate, ensuring that vibration energy can be absorbed by the composite layer at any location on the backplate. This avoids weak points in vibration transmission due to uncovered areas, thereby improving the overall vibration reduction effect. In addition, the damping characteristics of the composite layer can act uniformly on the backplate, suppressing local resonance phenomena and reducing the probability of broadband noise generation.

[0133] In some embodiments of this application, the thickness of the composite layer can be from 0.1 mm to 0.5 mm. Further, the thickness of the composite layer can be from 0.25 mm to 0.5 mm. Exemplarily, the thickness of the composite layer can be 0.25 mm, 0.28 mm, 0.3 mm, 0.33 mm, 0.35 mm, 0.38 mm, 0.40 mm, 0.43 mm, 0.45 mm, 0.48 mm, 0.50 mm, or any value between two adjacent values ​​mentioned above.

[0134] By adopting the above solution, the thickness of the composite layer should not be too large or too small. If the thickness is too large, it may affect the thermal conductivity of the brake pads; if the thickness is too small, it may not be able to effectively absorb vibrations, resulting in insufficient damping and noise problems. In addition, if the thickness of the composite layer is too large, it may hinder the transfer of heat from the friction layer to the backing plate, leading to excessively high local temperatures and affecting braking performance.

[0135] In some embodiments of this application, the thickness of the backplate can be 5 mm to 6 mm. Further, the thickness of the backplate can be 5 mm to 5.5 mm. Exemplarily, the thickness of the backplate can be 5 mm, 5.1 mm, 5.2 mm, 5.3 mm, 5.4 mm, 5.5 mm, or any value between two adjacent values ​​mentioned above.

[0136] By adopting the above solution, the thickness of the backplate is limited to between 5mm and 6mm, which helps to provide sufficient bending stiffness and avoid plastic deformation of the backplate caused by the pressure of the friction layer during braking. Furthermore, a 5-6mm backplate can store more frictional heat, helping to slow down the temperature rise rate of the friction surface and reduce the risk of thermal degradation. In addition, the natural frequency of a 5-6mm backplate avoids common braking vibration frequencies, reducing the risk of resonance.

[0137] In some embodiments of this application, the brake pads can be either sound-absorbing pads or brake pads.

[0138] Understandably, brake pads have a noise reduction effect and can be used in situations where noise reduction is required, such as as sound dampers or as brake pads.

[0139] This application discloses a brake pad, with reference to... Figure 4 The brake pad 100 may include:

[0140] Back panel 110; Back panel 110 uses a steel back;

[0141] Friction layer 200 is disposed on one side of back plate 110; and

[0142] Composite layer 120 is disposed between back plate 110 and friction layer 200; and

[0143] The composite layer 120 is disposed on the side of the back plate 110 opposite to the friction layer 200.

[0144] In some embodiments of this application, the noise generation rate of the brake pads ranges from 5.1% to 7.2%. Exemplarily, the noise generation rate of the brake pads can be 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, 7.0%, 7.1%, 7.2%, or any value between two adjacent values.

[0145] By adopting the above solution, the noise generation rate of the brake pad is within the above range, which ensures that the brake pad has low noise.

[0146] In some embodiments of this application, the difference between the natural frequency of the brake pad in the first temperature range and the natural frequency of the brake pad in the second temperature range is 0 Hz to 10 Hz. Exemplarily, the difference between the natural frequency of the brake pad in the first temperature range and the natural frequency of the brake pad in the second temperature range can be 0 Hz, 2 Hz, 3 Hz, 4 Hz, 5 Hz, 7 Hz, 8 Hz, 9 Hz, 10 Hz, and any value between two adjacent values ​​mentioned above.

[0147] In some embodiments of this application, the difference between the elastic modulus of the brake pad in the first temperature range and the elastic modulus of the brake pad in the second temperature range can be from 0 GPa to 0.6 GPa. Exemplarily, the difference between the elastic modulus of the brake pad in the first temperature range and the elastic modulus of the brake pad in the second temperature range can be 0 GPa, 0.1 GPa, 0.2 GPa, 0.3 GPa, 0.4 GPa, 0.5 GPa, 0.6 GPa, and any value between two adjacent values ​​mentioned above.

[0148] In some embodiments of this application, the difference between the natural frequency of the brake pad and the natural frequency of the brake disc can be greater than or equal to 20. Exemplarily, the difference between the natural frequency of the brake pad and the natural frequency of the brake disc can be 20, 22, 23, 25, 28, 30, 32, 33, 35, 38, 40, 42, 43, 45, 48, 50, or any value between two adjacent values ​​mentioned above.

[0149] By adopting the above scheme and adding inorganic elastic materials, it is beneficial to adjust the natural frequency of the brake pads so that the difference between the natural frequency of the brake pads and the natural frequency of the brake disc is greater than or equal to 20Hz, thereby avoiding the resonance range and achieving noise reduction.

[0150] According to a fifth aspect of this application, a method for preparing a brake pad is provided, referring to... Figure 5 The preparation method may include the following steps:

[0151] S100: The raw materials of the composite layer, the back plate and the friction layer are stacked in a preset order and then hot-pressed to obtain a preform.

[0152] S200. The preformed blank is cured to obtain the brake pad.

[0153] By adopting the above scheme, the raw materials of the composite layer, the back plate, and the friction layer are stacked in a preset order and then hot-pressed. Compared with the complex processes of riveting sound-absorbing sheets and step-by-step curing of multiple vibration damping layers in traditional processes, the production efficiency is significantly improved. Moreover, the temperature of hot pressing is significantly lower than that of traditional rubber vulcanization processes, which helps to significantly reduce energy consumption.

[0154] In some embodiments of this application, the preset order can be arranged according to the raw materials of the composite layer, the back plate, the raw materials of the composite layer, and the raw materials of the friction layer; the preset order can also be arranged according to the raw materials of the back plate, the raw materials of the composite layer, and the raw materials of the friction layer; and the preset order can also be arranged according to the raw materials of the composite layer, the back plate, and the raw materials of the friction layer.

[0155] In some embodiments of this application, the hot pressing temperature can be from 150°C to 170°C. Exemplarily, the hot pressing temperature can be 150°C, 152°C, 155°C, 157°C, 160°C, 163°C, 165°C, 167°C, 170°C, or any value between two adjacent values.

[0156] By adopting the above scheme, the temperature of hot pressing is set between 150°C and 170°C, which is conducive to softening or melting the material. If the temperature is too low, the material may not flow sufficiently, resulting in uneven hot pressing. If the temperature is too high, it may lead to the decomposition of the material or a decrease in its performance. The above temperature range can be regarded as the balance point between ensuring the fluidity of the material and avoiding thermal decomposition.

[0157] In some embodiments of this application, the pressure for hot pressing can be from 20 MPa to 40 MPa. Exemplarily, the pressure for hot pressing can be 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa, or any value between two adjacent values.

[0158] By adopting the above-mentioned method, the pressure range of hot pressing is between 20MPa and 40MPa, which is beneficial to improving the densification and interfacial bonding ability of the brake pads. Appropriate pressure can ensure that the material is fully filled into the hot pressing mold, reducing the porosity of the brake pads; at the same time, it is beneficial to enhance the bonding strength between layers. If the pressure is insufficient, it may lead to poor bonding between material layers; if the pressure is too high, it may damage the brake pads.

[0159] In some embodiments of this application, the curing temperature can be between 200°C and 250°C. Exemplarily, the curing temperature can be 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, or any value between two adjacent values.

[0160] By adopting the above-mentioned method, the curing process helps to further crosslink the organic components in the organic elastic materials and adhesive materials, thereby improving the crosslinking strength of the brake pads.

[0161] According to a sixth aspect of the embodiments of this application, a brake disc is provided, the brake disc including the aforementioned brake pads or the aforementioned composite layer or the aforementioned noise reduction structure.

[0162] By adopting the above solution, since the brake pads have the characteristic of maintaining a stable natural frequency at different temperatures, the brake disc also has the characteristic of maintaining a stable natural frequency at different temperatures, which helps to improve the performance of the brake disc.

[0163] According to a seventh aspect of the embodiments of this application, a vehicle is provided, the vehicle including the brake disc as described above, or the composite layer as described above, or the noise reduction structure as described above, or the brake pad as described above.

[0164] By adopting the above solution, vehicles equipped with the aforementioned brake discs have the advantages of low noise and smooth driving.

[0165] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0166] Example 1

[0167] A brake pad is prepared using the following steps:

[0168] S100, Provide the raw materials for the composite layer: 10wt% cashew nut shell oil modified phenolic resin, 80wt% nitrile rubber, and 10wt% expandable graphite, mix to obtain a mixture for later use;

[0169] S200. The steel backing is degreased and cleaned. Then, the mixture, the steel backing, the mixture and the raw materials of the friction layer are sequentially placed into a hot press mold and hot-pressed at 150°C to obtain a preform. The thickness of the composite layer formed by the mixture is 0.1 mm, and the thickness of the steel backing is 5 mm. The raw materials of the friction layer are composed of 5 wt% cashew nut shell oil modified phenolic resin, 20 wt% steel fiber, 10 wt% copper fiber, 2 wt% aramid fiber, 15 wt% graphite, 10 wt% stannous sulfide, 10 wt% chromite powder, 10 wt% alumina, and 18 wt% barium sulfate.

[0170] S300: The preformed blank is placed in an oven and cured at 220°C. After flat grinding, grooving and chamfering, the brake pad is obtained.

[0171] Example 2

[0172] A brake pad differs from that in Example 1 in that the thickness of the composite layer in the brake pad is different; in this example, the thickness of the composite layer is 0.25 mm.

[0173] Example 3

[0174] A brake pad differs from Example 1 in that the thickness of the composite layer in the brake pad is different; in this example, the thickness of the composite layer is 0.5 mm.

[0175] Example 4

[0176] A brake pad differs from Example 3 in that the composite layer in the brake pad is disposed between the backing plate and the friction layer. The backing plate is degreased and cleaned, and then the cleaned backing plate, the mixture, and the raw materials of the friction layer are sequentially placed into a hot press mold and hot-pressed at 150°C.

[0177] Example 5

[0178] A brake pad differs from Example 3 in that the composite layer in the brake pad is disposed on the side of the backing plate away from the friction layer. The backing plate is degreased and cleaned, and then the mixture, the backing plate, and the friction layer raw materials are sequentially placed into a hot press mold and hot-pressed at 150°C.

[0179] Example 6

[0180] A brake pad differs from Example 3 in that the composite layer formulation is different. The composite layer formulation in this example includes the following components:

[0181] The mixture consists of 10 wt% cashew nut shell oil-modified phenolic resin, 60 wt% nitrile rubber, and 30 wt% expandable graphite.

[0182] Example 7

[0183] A brake pad differs from Example 3 in that the composite layer formulation is different. The composite layer formulation in this example includes the following components:

[0184] The composition consists of 20 wt% cashew nut shell oil-modified phenolic resin, 53.3 wt% nitrile rubber, and 26.7 wt% expandable graphite.

[0185] Comparative Example 1

[0186] A brake pad is prepared using the following steps:

[0187] The raw materials for the composite layer are: 10 wt% cashew nut shell oil modified phenolic resin and 90 wt% nitrile rubber. The above components are mixed to obtain a mixture for later use.

[0188] The back plate is degreased and cleaned, and then the above mixture, steel back, mixture and friction layer raw materials are sequentially placed into a hot press mold and hot-pressed at 150°C to obtain a preformed blank; wherein, the thickness of the composite layer is 0.1 mm and the thickness of the steel back is 5 mm; the raw material of the friction layer is the same as the raw material of the friction layer in Example 1.

[0189] The preform is then placed in an oven and cured at 220°C. After flat grinding, grooving and chamfering, the brake pad is obtained.

[0190] Comparative Example 2

[0191] A brake pad is prepared using the following steps:

[0192] The back panel is degreased and cleaned to obtain a cleaned back panel for later use.

[0193] Then, the raw materials for the back plate and friction layer are placed into a hot press mold and hot-pressed at 150°C to obtain a preformed blank;

[0194] The preform is then placed in an oven and cured at 220°C. After flat grinding, grooving and chamfering, the brake pad is obtained.

[0195] Detection methods:

[0196] (1) Natural frequency: The natural frequency of the sample was tested at room temperature (20℃) and high temperature (300℃) in accordance with the IEC 60068-2-6 test standard;

[0197] (2) Elastic modulus: The elastic modulus of the sample was tested at room temperature (20℃) and high temperature (500℃) according to the JIS R 1644 test standard;

[0198] (3) Noise generation rate: The noise generation rate of the sample was tested according to the SAE J2521 test standard.

[0199] The test results are shown in Table 1:

[0200] Table 1

[0201]

[0202] As shown in Table 1, the brake pads prepared using the composite layer provided by this invention exhibit stable natural frequencies at both high and room temperatures, as well as a low noise generation rate. The difference between the natural frequencies of the samples in Examples 1-7 at room temperature and at high temperature is greater than or equal to 2 and less than or equal to 7, which enables the brake pads to maintain stable natural frequencies under different temperature conditions, thus helping to reduce braking noise.

[0203] Specifically, the natural frequencies at room temperature of Examples 1-7 are 1429-1463 Hz, the natural frequencies at high temperature are 1426-1456 Hz, the elastic modulus at room temperature is 15.1-17.8 MPa, the elastic modulus at high temperature is 15.5-18.1 MPa, and the noise generation rate is 5.1%-7.2%.

[0204] Compared with Comparative Examples 1-2, the composite layer of Examples 1-7 includes nitrile rubber and expandable graphite, while the composite layer of Comparative Example 1 lacks expandable graphite, and no composite layer is used in Comparative Example 2. According to the test results in Table 1, the introduction of the composite layer can maintain a stable natural frequency at both room temperature and high temperature, so that the natural frequency of the brake pad differs from the natural frequency of the brake disc (1406Hz) by more than 20Hz, which can avoid the resonance frequency with the brake disc and thus reduce the noise generation rate.

[0205] As can be seen from Examples 1-3, although the thickness of the composite layer was changed, the natural frequency change of the composite layer was consistent with the natural frequency change of the brake pad when the steel backing and friction layer structures remained unchanged. Increasing the thickness of the composite layer also increases the thickness of the prepared brake pad, which is beneficial for increasing the natural frequency of the brake pad. Simultaneously, the elastic modulus of the brake pad decreases, thus reducing the noise generation rate of the brake pad.

[0206] As can be seen from Examples 1 and 4-5, the distribution position of the composite layer on the backing plate is different in Examples 4-5. According to the test data in Table 1, the distribution position of the composite layer affects the natural frequency of the brake pad. The composite layer is distributed on both sides of the backing plate, which helps to increase the natural frequency of the brake pad, reduce the elastic modulus, and decrease the noise generation rate.

[0207] Compared with Example 3, Examples 6-7 changed the mass percentage of each component in the composite layer. According to the test data in Table 1, the formulation of the composite layer affects the natural frequency. The higher the proportion of nitrile rubber, the higher the natural frequency and the lower the noise generation rate.

[0208] The composite layer, noise reduction structure, brake pad and its preparation method, brake disc and vehicle provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A composite layer, characterized in that, The composite layer includes: An organic elastic material is used to adjust the natural frequency of the composite layer in a first temperature range; Inorganic elastic material is used to adjust the natural frequency of the composite layer in the second temperature range; The average temperature in the first temperature range is less than the average temperature in the second temperature range.

2. The composite layer according to claim 1, characterized in that, The difference between the natural frequency of the composite layer in the first temperature range and the natural frequency of the composite layer in the second temperature range is a preset threshold value. Preferably, the preset threshold value ranges from 0 to 10. Preferably, the preset threshold value ranges from greater than or equal to 2 to less than or equal to 7.

3. The composite layer according to claim 1 or 2, characterized in that, The first temperature range is greater than or equal to 0°C and less than or equal to 250°C; and / or The second temperature range is greater than or equal to 250°C and less than or equal to 500°C.

4. The composite layer according to any one of claims 1 to 3, characterized in that, The organic elastic material includes at least one of nitrile rubber, styrene-butadiene rubber, chlorobutyl rubber, fluororubber, silicone rubber, polyurethane elastomer, or polyolefin elastomer.

5. The composite layer according to any one of claims 1 to 3, characterized in that, The composite layer also includes an adhesive material; Preferably, the bonding material comprises modified phenolic resin and / or unmodified phenolic resin.

6. The composite layer according to claim 5, characterized in that, The modified phenolic resin includes at least one of nitrile-modified phenolic resin, cashew nut shell oil-modified phenolic resin, melamine-modified phenolic resin, molybdenum-modified phenolic resin, and boron-modified phenolic resin.

7. The composite layer according to any one of claims 1 to 3, characterized in that, The inorganic elastic material includes expandable materials and / or expandable materials; Preferably, the expandable material includes at least one of expandable graphite, expandable vermiculite, and expandable quartz; Preferably, the expanded material includes at least one of expanded graphite and expanded vermiculite.

8. The composite layer according to any one of claims 1 to 7, characterized in that, The mass ratio of the organic elastic material to the inorganic elastic material is greater than 1.

5. Preferably, the mass ratio of the organic elastic material to the inorganic elastic material ranges from 1.66 to 8.

9. The composite layer according to any one of claims 1 to 7, characterized in that, The organic elastic material comprises 50% to 80% by mass in the composite layer; and / or The inorganic elastic material in the composite layer comprises 10% to 30% by mass; and / or The adhesive material comprises 10% to 20% by mass in the composite layer.

10. A noise reduction structure, characterized in that, The noise reduction structure includes a composite layer as described in any one of claims 1 to 9.

11. A brake pad, characterized in that, The brake pads include: Back panel: A friction layer is disposed on one side of the back plate; and The composite layer as described in any one of claims 1 to 9, wherein the composite layer is disposed between the back plate and the friction layer; and / or The composite layer is disposed on the side of the back plate opposite to the friction layer.

12. The brake pad according to claim 11, characterized in that, The brake pad comprises two composite layers, one of which is disposed between the backing plate and the friction layer, and the other of which is disposed on the side of the backing plate opposite to the friction layer; and / or The projected area of ​​the composite layer on the back plate is greater than or equal to the area of ​​the back plate.

13. The brake pad according to claim 11 or 12, characterized in that, The thickness of the composite layer is 0.1 mm to 0.5 mm; Preferably, the thickness of the composite layer is 0.25 mm to 0.5 mm.

14. The brake pad according to claim 11 or 12, characterized in that, The thickness of the back plate is 5mm to 6mm; Preferably, the thickness of the back plate is 5 mm to 5.5 mm.

15. The brake pad according to any one of claims 11 to 14, characterized in that, The noise generation rate of the brake pads ranges from 5.1% to 7.2%; and / or The difference between the natural frequency of the brake pad in the first temperature range and the natural frequency of the brake pad in the second temperature range is 0 Hz to 10 Hz; and / or The difference between the elastic modulus of the brake pad in the first temperature range and the elastic modulus of the brake pad in the second temperature range is 0 GPa to 0.6 GPa; and / or The difference between the natural frequency of the brake pad and the natural frequency of the brake disc is greater than or equal to 20.

16. A method for preparing a brake pad as described in any one of claims 11 to 15, characterized in that, The preparation method includes the following steps: The raw materials of the composite layer, the back plate, and the friction layer are stacked in a preset order and then hot-pressed to obtain a preform. The preform is cured to obtain the brake pad.

17. The method for preparing brake pads according to claim 16, characterized in that, The hot pressing temperature is 150°C to 170°C; and / or The hot pressing pressure is 20 MPa to 40 MPa; and / or The curing temperature is 200°C to 250°C; and / or The preset order includes sorting by the raw materials of the composite layer, the back plate, and the friction layer, or sorting by the raw materials of the composite layer, the back plate, the composite layer, and the friction layer, or sorting by the raw materials of the back plate, the composite layer, and the friction layer.

18. A brake disc, characterized in that, The brake disc includes a brake pad as described in any one of claims 11 to 15, a composite layer as described in any one of claims 1 to 9, or a noise reduction structure as described in claim 10.

19. A vehicle, characterized in that, The vehicle includes a brake disc as described in claim 18, a composite layer as described in any one of claims 1 to 9, a noise reduction structure as described in claim 10, or a brake pad as described in any one of claims 11 to 15.

Images