Temperature rise numerical calculation method for brake disc of floating caliper disc brake

Abstract

The invention relates to a temperature rise numerical calculation method for a brake disc of a floating caliper disc brake, which belongs to the technical field of automobile disc brake, and comprises the following steps of: establishing a finite element analysis model of an automobile disc brake assembly, solving normal pressure data of a contact surface of the brake disc and a brake block of the brake assembly under a brake working condition, and calculating the temperature rise numerical value of the brake disc of the floating caliper disc brake; the contact area of the brake disc and the brake block is divided into five areas, and the pressure ratio coefficient of each area is calculated; calculating the function of the heat flux density on the unit area of the brake surface of the brake disc along with time in the braking process; establishing a brake disc fluid dynamic analysis model, and calculating convective heat transfer coefficients of the surface of the brake disc at different rotating speeds; establishing a brake disc temperature rise finite element analysis model, multiplying a heat flux function by a proportionality coefficient, and respectively applying the heat flux function and the proportionality coefficient to five areas of a brake surface of the brake disc; the convective heat transfer coefficient is given to the surface of the brake disc; and carrying out thermal analysis on the brake disc, and calculating the change process of the temperature of the brake disc along with time under various brake working conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile disc brakes and relates to a method for calculating the temperature rise of a brake disc of a floating caliper disc brake. Background Art

[0002] The braking process of a car is the process of converting part of the mechanical energy (kinetic energy, potential energy) into heat energy and dissipating it. During the braking process, 90% of the energy is absorbed by the brake disc and dissipated mainly through convection heat transfer. Under some severe braking conditions, such as long downhill conditions and emergency braking conditions on highways, the temperature of the brake disc will be very high. If the brake disc is not designed properly, serious thermal decay and thermal warping will occur, affecting the braking performance. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a method for calculating the temperature rise of a brake disc of a floating caliper disc brake.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A method for calculating the temperature rise of a floating caliper disc brake disc comprises the following steps:

[0006] S1: Establish a finite element analysis model of the automobile disc brake assembly, solve the normal pressure data of the contact surface between the brake disc and the brake pad under the braking condition, divide the contact area between the brake disc and the brake pad into 5 areas, and calculate the pressure ratio coefficient of each area;

[0007] S2: Calculate the heat flux density per unit area of ​​the brake disc during braking as a function of time based on vehicle parameters;

[0008] S3: Establish a brake disc fluid dynamics analysis model and calculate the convection heat transfer coefficient of the brake disc surface at different speeds;

[0009] S4: Establish a finite element analysis model for the temperature rise of the brake disc, multiply the heat flux function calculated in S2 by the proportional coefficient calculated in S1 and apply it to the five areas of the brake disc braking surface respectively; at the same time, assign the convection heat transfer coefficient calculated in S3 to the brake disc surface; perform brake disc thermal analysis and calculate the temperature change of the brake disc over time under various braking conditions.

[0010] Further, step S1 specifically includes the following steps:

[0011] S11: using general finite element analysis software ANSYS to perform mathematical discretization on a brake 3D model, wherein the brake 3D model includes a brake caliper assembly, a steering knuckle assembly, and a brake disc;

[0012] S12: Assign material parameters to the discrete units of each component: For isotropic materials, input Young's modulus, Poisson's ratio, and density; for anisotropic materials such as brake pads, treat them as orthogonal anisotropic materials and input 12 elastic constants measured in the experiment:

[0013]

[0014] The above formula is the relationship between stress, elastic constant and strain of orthogonal anisotropic materials, where C 11 ~C 66 is the elastic constant, σ x , σ y , σ z are the stresses in the x-axis, y-axis, and z-axis directions, τ xy is the shear stress in the x-axis and y-axis directions, τ yz is the shear stress in the y-axis and z-axis directions, τ zx is the shear stress in the z-axis and x-axis directions, ε x , ε y , ε z are the strains in the x-axis, y-axis, and z-axis directions, γ xy is the angular strain in the x-axis and y-axis directions, γ yz is the angular strain in the y-axis and z-axis directions, γ zx is the angular strain between the z-axis and the x-axis;

[0015] S13: By establishing the contact equations of the connecting surface elements between parts, the load transfer behavior between parts is simulated:

[0016]

[0017]

[0018] Where F n represents the normal contact force, K n represents the normal contact stiffness, u n Indicates the contact penetration, F T represents the tangential contact force, K T represents the tangential contact stiffness, u T represents the contact slip distance, μ represents the friction coefficient;

[0019] S14: Define constraints at the nodes connecting the steering knuckle and the vehicle body: input the constraint stiffness of the six degrees of freedom, add bolt preload to the simplified beam unit of the bolts in the structure to simulate the bolt tightening process, apply hydraulic load to the brake caliper assembly according to the temperature rise test conditions, and apply rotational displacement load to the brake disc to simulate the braking process;

[0020] S15: Establish the equilibrium equation, geometric equation and physical equation of the parts to solve the node parameters and obtain the finite element model;

[0021] The node parameters include node displacement, strain, stress and moment; the node displacement, strain and stress are solved by establishing equilibrium equations, geometric equations and physical equations, and then the normal pressure between the brake disc and the brake pad is multiplied by the area to obtain the normal force;

[0022]

[0023] Where: [K] is the overall stiffness matrix of the structure, {u} is the displacement vector, {P} is the load vector, ε is the strain, σ is the stress, and E is the Young's modulus;

[0024] Finally, the normal force in each area is divided by the total normal force to obtain the pressure proportionality coefficient in each area.

[0025] Furthermore, in step S2, the heat flux densities of a single front brake disc and a single rear brake disc are respectively:

[0026]

[0027]

[0028] Where: v1 represents the initial braking speed, v2 represents the final braking speed, t represents the braking time; M represents the full load weight of the vehicle; A f Indicates the friction ring area of ​​the front brake disc, A r It represents the friction ring area of ​​the rear brake disc; δ represents the heat flux density distribution coefficient between the brake disc and the brake pad; β represents the front and rear braking force distribution coefficient.

[0029] Further, the specific implementation steps of step S3 are as follows:

[0030] During the braking process, the heat consumed by the air around the brake disc through convection heat transfer to the brake disc is:

[0031] Q=hSΔt

[0032] Where Q is the heat consumed by convection heat transfer, h is the convection heat transfer coefficient, S is the heat dissipation area, and Δt is the temperature difference between the brake disc and the surrounding air;

[0033] Use CFD software to simulate and analyze the convective heat transfer process of the brake disc, and obtain the convective heat transfer coefficient function of the brake disc at different speeds and disc temperatures;

[0034] The FLUENT fluid dynamics simulation software is used to establish a brake disc fluid dynamics analysis model, which consists of an air domain and a brake disc wrapped in the air domain. The air domain has air inlets and outlets on both sides, and the brake disc is located inside the air domain and rotates in the air domain. The size of the air domain is 5 times that of the brake disc body. The three-dimensional solid models of the brake disc and the air domain are imported into the ICEM CFD module in ANSYS, and tetrahedral meshing is performed on them. The FLUENT module is applied, and the k-ω turbulence model is adopted to set the inlet velocity of the air domain, the brake disc speed, the air domain temperature, and the initial temperature of the brake disc. The MRF multi-reference system model is used to simulate the rotation process of the brake disc in idling, and the convective heat transfer coefficient of the brake disc surface at different times, vehicle speeds, and different positions is automatically calculated based on the FLUENT_CFD calculation program.

[0035] Further, step S4 specifically includes the following steps:

[0036] S41: Scan the contact surface between the brake pad and the brake disc to form a friction ring surface area, and divide the friction ring into 5 equal areas according to the method of S1, and then perform mesh division;

[0037] S42: Define the material parameters required for thermal analysis of brake discs, including density, thermal expansion coefficient, thermal conductivity and specific heat capacity;

[0038] S43: Multiply the heat flux density function calculated in S2 by the proportional coefficient calculated in S1 and apply them to the five areas of the friction ring respectively; at the same time, apply the convection heat transfer coefficient calculated in S3 to the brake disc surface, and use the ANSYS transient thermal analysis model to solve the temperature rise of the brake disc under different working conditions, and correct the analysis model through the temperature rise test data to control the analysis error within 10% to 15%.

[0039] The beneficial effect of the present invention is that the present invention provides a more accurate method for calculating the temperature rise of a brake disc, which can effectively guide the design of the brake disc, shorten the development cycle, and save costs.

[0040] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0042] Figure 1This is a schematic diagram of the brake 3D model;

[0043] Figure 2 The fluid dynamics analysis model for the brake disc. DETAILED DESCRIPTION

[0044] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0045] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0046] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0047] The present invention provides a method for calculating the temperature rise of a brake disc of a floating caliper disc brake, comprising the following steps:

[0048] S1: Establish a finite element analysis model for the automotive disc brake assembly, solve the normal pressure data of the contact surface between the brake disc and the brake pad under braking conditions, divide the contact area between the brake disc and the brake pad into 5 equal areas in the radial direction, and calculate the normal pressure ratio of each area. The purpose is: since the pressure on the braking surface of the floating caliper brake is not evenly distributed during braking, the greater the pressure in the area, the greater the friction work and the higher the temperature. Through CAE simulation analysis of the pressure ratio of different areas during braking, energy is distributed: the heat flux calculated in S2 will make the calculation result more accurate. Figure 1 As shown, step S1 specifically includes the following steps:

[0049] S1_1: using the general finite element analysis software ANSYS to perform mathematical discretization on the brake 3D model, wherein the brake 3D model includes a brake caliper assembly, a steering knuckle assembly, and a brake disc;

[0050] S1_2: Assign material parameters to the discrete units of each component: For isotropic materials, input Young's modulus, Poisson's ratio, and density; for anisotropic materials such as brake pads, treat them as orthogonal anisotropic materials and input 12 elastic constants measured in the experiment:

[0051]

[0052] The above formula is the relationship between stress, elastic constant and strain of orthogonal anisotropic materials, where C 11 ~C 66 is the elastic constant, σ x , σ y , σ z are the stresses in the x-axis, y-axis, and z-axis directions, τ xy is the shear stress in the x-axis and y-axis directions, τ yz is the shear stress in the y-axis and z-axis directions, τ zx is the shear stress in the z-axis and x-axis directions, ε x , ε y , ε z are the strains in the x-axis, y-axis, and z-axis directions, γ xy is the angular strain in the x-axis and y-axis directions, γ yz is the angular strain in the y-axis and z-axis directions, γ zx is the angular strain between the z-axis and the x-axis;

[0053] S1_3: By establishing the contact equation of the connecting surface elements between parts, the load transfer behavior between parts is simulated:

[0054]

[0055]

[0056] Where F n represents the normal contact force, K n represents the normal contact stiffness, u n Indicates the contact penetration, F T represents the tangential contact force, K T represents the tangential contact stiffness, u T represents the contact slip distance, μ represents the friction coefficient;

[0057] S1_4: Define constraints at the nodes connecting the steering knuckle and the vehicle body: input the constraint stiffness of the six degrees of freedom, add bolt preload to the simplified beam unit of the bolts in the structure to simulate the bolt tightening process, apply hydraulic load to the brake caliper assembly according to the temperature rise test conditions, and apply rotational displacement load to the brake disc to simulate the braking process;

[0058] S1_5: Establish the equilibrium equation, geometric equation and physical equation of the parts to solve the node parameters and obtain the finite element model;

[0059] The node parameters include node displacement, strain, stress and moment. The node displacement, strain and stress are solved by establishing equilibrium equations, geometric equations and physical equations. The normal pressure between the brake disc and the brake pad is multiplied by the area to obtain the normal force.

[0060]

[0061] Where: [K] is the overall stiffness matrix of the structure, {u} is the displacement vector, {P} is the load vector, ε is the strain, σ is the stress, and E is the Young's modulus.

[0062] Dividing the normal force in each region by the total normal force yields the pressure proportionality coefficient for each region.

[0063] S2: Calculate the heat flux density on the braking surface of the brake disc as a function of time during braking based on the vehicle parameters. The specific implementation is as follows:

[0064] S2_1: The braking process of a car is the process of converting part of the mechanical energy (kinetic energy, potential energy) into heat energy and dissipating it. When the braking acceleration is large, the brake almost bears the task of dissipating all the mechanical energy of the car. The energy load of the brake disc is evaluated by its heat flux density, which is the unit energy load, that is, the heat energy borne by the unit friction area per unit time, in W / mm2.

[0065] The heat flux densities of a single front brake disc and a single rear brake disc are:

[0066]

[0067]

[0068] Where: v1 represents the initial braking speed, v2 represents the final braking speed, t represents the braking time; M represents the full load weight of the vehicle; A f Indicates the friction ring area of ​​the front brake disc, A r It represents the friction ring area of ​​the rear brake disc; δ represents the heat flux density distribution coefficient between the brake disc and the brake pad; β represents the front and rear braking force distribution coefficient.

[0069] S3: Establish a brake disc fluid dynamics analysis model to calculate the convection heat transfer coefficient of the brake disc surface at different speeds.

[0070] Step S3 is specifically implemented as follows:

[0071] During the braking process, the temperature of the brake disc continues to rise. At the same time, the air flow around the brake disc will produce a strong convection heat transfer effect to dissipate the heat of the brake disc. The calculation formula is:

[0072] Q=hSΔt

[0073] Where Q is the heat consumed by convection heat transfer, h is the convection heat transfer coefficient, S is the heat dissipation area, and Δt is the temperature difference between the brake disc and the surrounding air.

[0074] In the past, the convective heat transfer coefficient was calculated by an empirical formula to obtain the average convective heat transfer coefficient (constant) of the brake disc, and the calculation error reached more than 30%, because the convective heat transfer coefficient is related to the air flow rate and the structural form. The present invention proposes a method of using CFD software to simulate and analyze the convective heat transfer process of the brake disc, and obtain the convective heat transfer coefficient function of the brake disc at different speeds and disc temperatures. The FLUENT fluid dynamics simulation software is used to establish a brake disc fluid dynamics analysis model, such as Figure 2 As shown in the figure, the model consists of an air domain and a brake disc wrapped in the air domain. The two sides of the air domain are analyzed as air inlets and outlets. The brake disc (SOLID) is located inside the air domain and rotates in the air domain. In order to avoid the interference of the square geometric wall on the air flow field, the size of the air domain is designed to be 5 times that of the brake disc body. The three-dimensional solid model of the brake disc and the air domain is imported into the ICEM CFD module in ANSYS to perform tetrahedral meshing. The FLUENT module is applied, and the k-ω turbulence model is adopted. The inlet velocity of the air domain (i.e., vehicle speed) and the brake disc speed are set. The air domain temperature is set to 20℃, and the initial temperature of the brake disc is set to 60℃. The MRF multi-reference system model is used to simulate the rotation process of the brake disc in idling, and the convective heat transfer coefficient of the brake disc surface at different times, vehicle speeds, and different positions is automatically calculated based on the FLUENT_CFD calculation program.

[0075] S4: Establish a finite element analysis model for the temperature rise of the brake disc, multiply the heat flux function calculated in S2 by the proportionality coefficient calculated in S1 and apply it to the five areas of the brake disc braking surface. At the same time, assign the convection heat transfer coefficient calculated in S3 to the brake disc surface. Perform a thermal analysis of the brake disc and calculate the temperature change of the brake disc over time under various braking conditions. Step S4 is specifically implemented as follows:

[0076] S4_1: Scan the contact surface between the brake pad and the brake disc to form the friction ring surface area, and divide the friction ring into 5 equal areas according to the method of S1, and then perform mesh division.

[0077] S4_2: Define the material parameters required for thermal analysis of brake discs: density, thermal expansion coefficient, thermal conductivity, specific heat capacity, etc.

[0078] S4_3: Multiply the heat flux density function calculated in S2 by the proportional coefficient calculated in S1 and apply them to the five areas of the friction ring. At the same time, apply the convection heat transfer coefficient calculated in S3 to the brake disc surface, and use the ANSYS transient thermal analysis model to solve the temperature rise of the brake disc under different working conditions. The analysis model is corrected by the temperature rise test data to control the analysis error within 10% to 15%.

[0079] In the above embodiments, the description's reference to "this embodiment" indicates that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least some embodiments, but not necessarily all embodiments. Multiple occurrences of "this embodiment" do not necessarily all refer to the same embodiment.

[0080] In the above-described embodiments, although the invention has been described in conjunction with specific embodiments of the invention, many substitutions, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description. For example, other storage structures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed. Embodiments of the invention are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of the appended claims.

[0081] This embodiment further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, any one of the methods in this embodiment is implemented.

[0082] This embodiment also provides an electronic terminal, including: a processor and a memory;

[0083] The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes any one of the methods in this embodiment.

[0084] The computer-readable storage medium in this embodiment can be understood by ordinary technicians in this field: all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

[0085] The electronic terminal provided in this embodiment includes a processor, a memory, a transceiver and a communication interface. The memory and the communication interface are connected to the processor and the transceiver and complete communication with each other. The memory is used to store computer programs, the communication interface is used to communicate, and the processor and the transceiver are used to run computer programs so that the electronic terminal executes each step of the above method.

[0086] In this embodiment, the memory may include a random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0087] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0088] The present invention can be used in many general or special computing system environments or configurations, such as personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and the like.

[0089] The present invention may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for calculating the temperature rise of a floating caliper disc brake disc, characterized in that: The following steps are involved: S1: Establish a finite element analysis model of the automobile disc brake assembly, solve the normal pressure data of the contact surface between the brake disc and the brake pad under the braking condition, divide the contact area between the brake disc and the brake pad into 5 areas, and calculate the pressure ratio coefficient of each area; S2: Calculate the heat flux density per unit area of ​​the brake disc during braking as a function of time based on vehicle parameters; S3: Establish a brake disc fluid dynamics analysis model and calculate the convection heat transfer coefficient of the brake disc surface at different speeds; S4: Establish a finite element analysis model for the temperature rise of the brake disc, multiply the heat flux function calculated in S2 by the proportional coefficient calculated in S1 and apply it to the five areas of the brake disc braking surface respectively; at the same time, assign the convection heat transfer coefficient calculated in S3 to the brake disc surface; perform brake disc thermal analysis and calculate the temperature change of the brake disc over time under various braking conditions.

2. The method for calculating the temperature rise of a floating caliper disc brake disc according to claim 1, characterized in that: Step S1 specifically includes the following steps: S11: using general finite element analysis software ANSYS to perform mathematical discretization on a brake 3D model, wherein the brake 3D model includes a brake caliper assembly, a steering knuckle assembly, and a brake disc; S12: Assign material parameters to the discrete units of each component: For isotropic materials, input Young's modulus, Poisson's ratio, and density; for anisotropic materials such as brake pads, treat them as orthogonal anisotropic materials and input 12 elastic constants measured in the experiment: The above formula is the relationship between stress, elastic constant and strain of orthogonal anisotropic materials, where C 11 ~C 66 is the elastic constant, σ x , σ y , σ z are the stresses in the x-axis, y-axis, and z-axis directions, τ xy is the shear stress in the x-axis and y-axis directions, τ yz is the shear stress in the y-axis and z-axis directions, τ zx is the shear stress in the z-axis and x-axis directions, ε x , ε y , ε z are the strains in the x-axis, y-axis, and z-axis directions, γ xy is the angular strain in the x-axis and y-axis directions, γ yz is the angular strain in the y-axis and z-axis directions, γ zx is the angular strain between the z-axis and the x-axis; S13: By establishing the contact equations of the connecting surface elements between parts, the load transfer behavior between parts is simulated: Where F n represents the normal contact force, K n represents the normal contact stiffness, u n Indicates the contact penetration, F T represents the tangential contact force, K T represents the tangential contact stiffness, u T represents the contact slip distance, μ represents the friction coefficient; S14: Define constraints at the nodes connecting the steering knuckle and the vehicle body: input the constraint stiffness of the six degrees of freedom, add bolt preload to the simplified beam unit of the bolts in the structure to simulate the bolt tightening process, apply hydraulic load to the brake caliper assembly according to the temperature rise test conditions, and apply rotational displacement load to the brake disc to simulate the braking process; S15: Establish the equilibrium equation, geometric equation and physical equation of the parts to solve the node parameters and obtain the finite element model; The node parameters include node displacement, strain, stress and moment; the node displacement, strain and stress are solved by establishing equilibrium equations, geometric equations and physical equations, and then the normal pressure between the brake disc and the brake pad is multiplied by the area to obtain the normal force; Where: [K] is the overall stiffness matrix of the structure, {u} is the displacement vector, {P} is the load vector, ε is the strain, σ is the stress, and E is the Young's modulus; Finally, the normal force in each area is divided by the total normal force to obtain the pressure proportionality coefficient in each area.

3. The method for calculating the temperature rise of a brake disc of a floating caliper disc brake according to claim 1, characterized in that: In step S2, the heat flux densities of a single front brake disc and a single rear brake disc are respectively: Where: v1 represents the initial braking speed, v2 represents the final braking speed, t represents the braking time; M represents the full load weight of the vehicle; A f Indicates the friction ring area of ​​the front brake disc, A r It represents the friction ring area of ​​the rear brake disc; δ represents the heat flux density distribution coefficient between the brake disc and the brake pad; β represents the front and rear braking force distribution coefficient.

4. The method for calculating the temperature rise of a brake disc of a floating caliper disc brake according to claim 1, characterized in that: The specific implementation steps of step S3 are as follows: During the braking process, the heat consumed by the air around the brake disc through convection heat transfer to the brake disc is: Q=hSΔt Where Q is the heat consumed by convection heat transfer, h is the convection heat transfer coefficient, S is the heat dissipation area, and Δt is the temperature difference between the brake disc and the surrounding air; Use CFD software to simulate and analyze the convective heat transfer process of the brake disc, and obtain the convective heat transfer coefficient function of the brake disc at different speeds and disc temperatures; The FLUENT fluid dynamics simulation software is used to establish a brake disc fluid dynamics analysis model, which consists of an air domain and a brake disc wrapped in the air domain. The air domain has air inlets and outlets on both sides, and the brake disc is located inside the air domain and rotates in the air domain. The size of the air domain is 5 times that of the brake disc body. The three-dimensional solid model of the brake disc and the air domain is imported into the ICEM CFD module in ANSYS, and tetrahedral meshing is performed on it. The FLUENT module is applied, and the k-ω turbulence model is adopted to set the inlet velocity of the air domain, the brake disc speed, the air domain temperature, and the initial temperature of the brake disc. The MRF multi-reference model is used to simulate the rotation process of the brake disc in idling, and the convection heat transfer coefficient of the brake disc surface at different times, vehicle speeds, and different positions is automatically calculated based on the FLUENT_CFD calculation program.

5. The method for calculating the temperature rise of a brake disc of a floating caliper disc brake according to claim 1, characterized in that: Step S4 specifically includes the following steps: S41: Scan the contact surface between the brake pad and the brake disc to form a friction ring surface area, and divide the friction ring into 5 equal areas according to the method of S1, and then perform mesh division; S42: Define the material parameters required for thermal analysis of brake discs, including density, thermal expansion coefficient, thermal conductivity and specific heat capacity; S43: Multiply the heat flux density function calculated in S2 by the proportional coefficient calculated in S1 and apply them to the five areas of the friction ring respectively; at the same time, apply the convection heat transfer coefficient calculated in S3 to the brake disc surface, and use the ANSYS transient thermal analysis model to solve the temperature rise of the brake disc under different working conditions, and correct the analysis model through the temperature rise test data to control the analysis error within 10% to 15%.

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