Friction plate pressure distribution simulation evaluation method and system

Abstract

The invention provides a friction plate pressure distribution simulation evaluation method and system, and relates to the technical field of brake system testing, and the method comprises the steps: setting the parameters of all parts in a simulation model of a brake system and the connection relation between all parts; simulation is started after boundary conditions and loads of the simulation model are set; according to a contact pressure result obtained through simulation, a variable coefficient value for evaluating the contact pressure of the friction plate is obtained through calculation; and repeatedly executing for multiple times, adjusting the set parameters during each time of repeating, and comparing all the variable coefficient values to compare the uniformity degree of surface contact pressure distribution of different friction plates. The method has the beneficial effects that the evaluation objectivity and accuracy are improved: the uniformity of pressure distribution is quantified by calculating a contact pressure variation coefficient, so that the defect that a traditional method depends on subjective observation of a pressure cloud picture is overcome, and the evaluation is more objective; and the optimal design scheme is rapidly screened out through multiple parameter adjustment and simulation comparison, and time-consuming links in a traditional optimization process are greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of brake system testing, and in particular to a method and system for simulating and evaluating the pressure distribution of a friction plate. Background Art

[0002] As vehicles evolve toward higher speeds, electrification, and intelligent driving, braking systems face increasingly demanding operating conditions. Pressure distribution refers to the pressure distribution at the contact surface between the friction pad and the brake disc when the brake caliper pushes the piston, clamping the friction pad against the brake disc. Pressure distribution at the friction pad interface directly impacts the stability of brake torque output, the efficiency of frictional heat generation and dissipation, and component life. Traditional brake system designs often assume uniform pressure, but the actual contact surface exhibits significant non-uniformity due to factors such as brake pressure and brake disc rotation. Numerous studies have shown that brake judder is directly related to imbalanced pressure distribution. Therefore, understanding the mechanism of pressure distribution and establishing high-precision prediction models are crucial for improving brake system reliability, comfort, and economy.

[0003] Currently, pressure distribution is mainly collected using Tecscan instruments for measurement or by obtaining a pressure distribution diagram of the friction plate contact interface during complex modal simulation. This is followed by a subjective judgment of whether the pressure distribution on the friction plate contact interface is uniform. This is then optimized by designing friction plate grooves and chamfers, and then compared with the NVH bench test results based on SAE-J-2521. This is time-consuming and highly subjective, and cannot effectively evaluate the friction plate contact surface pressure. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a friction plate pressure distribution simulation evaluation method, comprising:

[0005] Step S1, setting the parameters of each component in the simulation model of the brake system and the connection relationship between the components;

[0006] Step S2, setting the boundary conditions and loads of the simulation model and then starting the simulation;

[0007] Step S3, calculating a coefficient of variation of the contact pressure of the friction plate based on the contact pressure result obtained by simulation;

[0008] Step S4, repeatedly executing steps S1-S3 multiple times, and adjusting the parameters set in step S1 during each repetition, and comparing all the coefficient of variation values to compare the uniformity of the surface contact pressure distribution of different friction plates.

[0009] Preferably, the simulation model is preprocessed before executing step S1, including deleting the friction plate chamfer, the brake caliper oil inlet hole and the bolt hole chamfer in the simulation model.

[0010] Preferably, the components in the simulation model include a brake disc, a friction plate, a brake bracket, a brake caliper, a piston and a guide pin.

[0011] Preferably, the step S1 includes:

[0012] Step S11, meshing each component in the simulation model;

[0013] Step S12, setting the connection relationship between the brake disc and the friction plate, the clamping claw of the brake caliper and the outer friction plate, the piston and the inner friction plate, the guide pin and the brake bracket, and the guide pin and the brake caliper to surface contact;

[0014] Step S13, setting the connection relationship between the friction material inside the friction plate, the steel back and the silencer plate to a binding contact, and setting the connection relationship between the bolt inside the guide pin and the pin to a binding contact.

[0015] Preferably, the step S2 includes:

[0016] Step S21, applying pressure to the piston and the cylinder bottom surface of the brake caliper to simulate real hydraulic pressure;

[0017] Step S22: applying a rotation speed to the brake disc through the keyword Motion to set the rotation axis and reference point of the brake disc.

[0018] Preferably, step S3 includes:

[0019] Step S31, obtaining a contact pressure cloud map obtained by simulation, and obtaining a unit pressure value of each unit in the contact pressure cloud map as the contact pressure result;

[0020] Step S32: Calculate the coefficient of variation based on the unit pressure values of all units.

[0021] The present invention further provides a friction plate pressure distribution simulation evaluation system, which is applied to the above-mentioned pressure distribution simulation evaluation method and includes:

[0022] A model setting module is used to set the parameters of each component in the simulation model of the braking system and the connection relationship between the components;

[0023] A condition setting module, used to set boundary conditions and loads for the simulation model before starting simulation;

[0024] A calculation module, configured to calculate a coefficient of variation value for evaluating the contact pressure of each friction plate based on the contact pressure results obtained by simulation;

[0025] An evaluation module is connected to the calculation module and is used to repeatedly execute the model setting module, the condition setting module and the calculation module, and adjust the parameters set in the model setting module during each repetition, and compare all the coefficient of variation values to compare the uniformity of the surface contact pressure distribution of different friction plates.

[0026] Preferably, it also includes a model preprocessing module, which is connected to the model setting module and is used to delete the friction plate chamfers, brake caliper oil inlet holes and bolt hole chamfers in the simulation model.

[0027] Preferably, the components in the simulation model include a brake disc, a friction plate, a brake bracket, a brake caliper, a piston and a guide pin.

[0028] Preferably, the model setting module includes:

[0029] A mesh division unit, used for performing mesh division on each component in the simulation model;

[0030] a surface contact setting unit, for setting the connection relationship between the brake disc and the friction plate, the clamping claw of the brake caliper and the outer friction plate, the piston and the inner friction plate, the guide pin and the brake bracket, and the guide pin and the brake caliper to surface contact;

[0031] The binding contact setting unit is used to set the connection relationship between the friction material, steel back and silencer plate inside the friction plate to binding contact, and set the connection relationship between the bolt and pin inside the guide pin to binding contact.

[0032] The above technical solution has the following advantages or beneficial effects:

[0033] 1. Improve the objectivity and accuracy of evaluation: By calculating the coefficient of variation (CV value) of contact pressure, the uniformity of pressure distribution is quantified, avoiding the shortcomings of traditional methods that rely on subjective observation of pressure cloud maps, making the evaluation more statistically based and objective.

[0034] 2. Significantly shorten the development cycle: Using simulation models to replace physical tests (such as the SAE-J-2521 NVH bench test), through multiple parameter adjustments and simulation comparisons, the optimal design solution can be quickly screened, significantly reducing the time-consuming steps in the traditional optimization process.

[0035] 3. Optimization efficiency and improved flexibility: Supports dynamic adjustment of multiple parameters (such as friction plate material, structure, speed, etc.). Combined with CV value comparison, it can quickly locate the cause of uneven pressure distribution and optimize the design, reducing trial and error costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 FIG1 is a flow chart of a method for simulating and evaluating the pressure distribution of a friction plate in a preferred embodiment of the present invention;

[0037] Figure 2 Schematic diagram of a sub-flow chart of step S1 in a preferred embodiment of the present invention;

[0038] Figure 3 Schematic diagram of a sub-flow chart of step S2 in a preferred embodiment of the present invention;

[0039] Figure 4 FIG1 is a schematic diagram of an assembly of a braking system in a preferred embodiment of the present invention;

[0040] Figure 5 The contact pressure distribution diagram of the friction plate in a preferred embodiment of the present invention is as follows;

[0041] Figure 6 The figure is a structural diagram of a friction plate pressure distribution simulation evaluation system in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment, and other embodiments may also fall within the scope of the present invention as long as they conform to the gist of the present invention.

[0043] In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a friction plate pressure distribution simulation evaluation method is provided. Figure 1 As shown, including:

[0044] Step S1, setting the parameters of each component in the simulation model of the brake system and the connection relationship between the components;

[0045] Step S2, setting the boundary conditions and loads of the simulation model and then starting the simulation;

[0046] Step S3, calculating a coefficient of variation of the contact pressure of the friction plate based on the contact pressure result obtained by simulation;

[0047] Step S4, repeatedly executing steps S1-S3 multiple times, and adjusting the parameters set in step S1 during each repetition, and comparing all coefficient of variation values to compare the uniformity of the surface contact pressure distribution of different friction plates.

[0048] In this embodiment, the components in the simulation model include a brake disc, a friction plate, a brake bracket, a brake caliper, a piston, and a guide pin.

[0049] Specifically, in this embodiment, first, a simulation model of the brake system assembly is opened in UG (UG software is the abbreviation of Unigraphics NX, which is an advanced CAD / CAM / CAE software developed by Siemens of Germany and is widely used in the automotive, aviation, machinery, electronics and other manufacturing industries. UG software has powerful modeling, analysis, processing and simulation functions); the main components in the simulation model are the brake disc, friction pad, back plate, brake bracket, brake caliper, piston, and guide pin.

[0050] In a preferred embodiment of the present invention, Figure 2 As shown, step S1 includes:

[0051] Step S11, meshing each component in the simulation model and setting parameters;

[0052] Step S12, setting the connection relationship between the brake disc and the friction plate, the clamping claw of the brake caliper and the outer friction plate, the piston and the inner friction plate, the guide pin and the brake bracket, and the guide pin and the brake caliper to surface contact;

[0053] Step S13, setting the connection relationship between the friction material inside the friction plate, the steel back and the silencer plate to a binding contact, and setting the connection relationship between the bolt inside the guide pin and the pin to a binding contact.

[0054] Specifically, in this embodiment, the simulation model is imported into simulation software, such as Abaqus (Abaqus is a powerful finite element software for engineering simulation, capable of solving problems ranging from relatively simple linear analysis to many complex nonlinear problems). Based on the theory of elastic contact mechanics, the pressure distribution on the contact surface of the friction pad during braking, under the dual influence of applied braking pressure and the rotation of the brake disc, is simulated. The material module in Abaqus sets and assigns material parameters to each component, and the meshing module performs meshing of each component. Meshing is the process of discretizing a continuous geometric model into a mesh structure composed of small units (such as triangles, quadrilaterals, hexahedrons, etc.). In simulation analysis, this is a fundamental step in finite element calculations, the purpose of which is to convert complex physical models into discrete data that can be processed by computers.

[0055] Subsequently, according to the actual working conditions of the braking system, the connection relationship between the brake disc and the friction plate, the claw of the brake caliper and the outer friction plate, the piston and the inner friction plate, the guide pin and the brake bracket, the guide pin and the brake caliper, and the back plate and the brake bracket is set to surface-to-surface contact; the connection relationship between the friction material, the steel back and the muffler inside the friction plate is set to bonded contact ("Bonded Contact" is a term in engineering simulation (such as finite element analysis, FEA) and mechanical design, which refers to the establishment of a completely fixed constraint relationship between two contacting surfaces, so that they cannot undergo relative motion (including translation and rotation) when subjected to force or deformation. Its core meaning is to simulate the "rigid connection" between two objects, similar to the effect of welding, bonding or bolting.).

[0056] In a preferred embodiment of the present invention, Figure 3 As shown, step S2 includes:

[0057] Step S21, applying pressure to the piston and the cylinder bottom surface of the brake caliper to simulate real hydraulic pressure;

[0058] Step S22: applying a rotation speed to the brake disc through the keyword Motion to set the rotation axis and reference point of the brake disc.

[0059] Specifically, in this embodiment, Figure 4 This is a schematic diagram of the brake system assembly. This brake system is common, and its internal structure can be found in the prior art. Instead of disassembling it and labeling each component one by one, we set the corresponding boundary conditions and loads in the Abaqus load module. The first step is to apply pressure to the caliper cylinder bottom and piston surface to simulate the brake pressure during braking. The bolt holes of the brake disc and brake bracket are fixed in position, and pressure is applied to the piston and the bottom surface of the brake caliper cylinder to simulate real hydraulic pressure.

[0060] The second step is to apply a rotational speed to the brake disc. This is done using the Motion keyword in Abaqus to simulate the disc's rotation during braking. This keyword can directly define rotational motion and precisely control the laws of motion to set the precise axis of rotation and reference point.

[0061] Set the analysis type to Statics.

[0062] After completing all settings, submit the job to perform pressure distribution simulation calculations.

[0063] In a preferred embodiment of the present invention, step S3 includes:

[0064] Step S31, obtaining a contact pressure cloud map obtained by simulation, and obtaining a unit pressure value of each unit in the contact pressure cloud map as a contact pressure result;

[0065] Step S32: Calculate the coefficient of variation based on the unit pressure values of all units.

[0066] Specifically, in this embodiment, after the simulation calculation is completed, according to the friction plate surface contact pressure cloud map ( Figure 5 ) to export the contact pressure result data of the friction plate surface (Abaqus contact pressure cloud map is actually a picture composed of a group of data arranged according to the data size. Each unit has a specific data value. The software can select the surface you want to export and then export the data value).

[0067] Conventional technology generally relies on directly observing the contact pressure cloud diagram on the friction plate surface to subjectively determine whether the pressure distribution meets the requirements. However, this embodiment calculates the coefficient of variation (CV) of the contact pressure values of a single friction plate based on statistical principles. The CV is used to evaluate and measure the dispersion of the contact pressure values, allowing for standardized comparison. The following is the calculation method for CV:

[0068] CV = (standard deviation SD / mean) * 100%

[0069] Specific evaluation method of "using CV value to evaluate contact pressure":

[0070] The evaluation criteria for the coefficient of variation CV value in statistics are:

[0071] CV < 15%: low variation (data set is concentrated, fluctuation is small;)

[0072] 15%≤CV≤30%: (moderate variation, fluctuations are controllable;)

[0073] CV>30%: High variation (data dispersion and large fluctuations);

[0074] Generally, a CV value within 30% indicates manageable data fluctuations and uniform contact pressure distribution. However, if the data has a long tail, the standard can be appropriately lowered. Furthermore, since a smaller CV value indicates a more even distribution and less fluctuation, it also indicates uniform contact pressure between the friction pad and the brake disc.

[0075] Through multiple simulations, the parameters set in the simulation software are adjusted each time. For example, the material parameters of the friction plate in the simulation model are adjusted to simulate the use of different friction plates, the components included in the simulation model are adjusted, and the material parameters of the components are adjusted to simulate the replacement of other parts. The rotation speed and the applied pressure value can also be adjusted to form different test schemes for simulation. The CV values of the friction plates of different schemes are compared, so as to select a scheme with more uniform contact pressure, which can effectively reduce abnormal wear and brake noise in actual tests.

[0076] In a preferred embodiment of the present invention, the simulation model is pre-processed before executing step S1, including deleting the chamfers of the friction plate, the oil inlet hole of the brake caliper, and the chamfers of the bolt holes in the simulation model.

[0077] Specifically, the simulation model used for simulation testing in this embodiment includes components such as brake discs, friction plates, brake brackets, brake calipers, pistons and guide pins. The product components are relatively rich, and only the chamfers of the friction plates and the oil inlet holes of the brake calipers are deleted, as well as unimportant chamfer features at some bolt hole positions. These structures that have little effect on the contact pressure of the friction plates are deleted to achieve the purpose of simplifying the model, improving efficiency and ensuring the accuracy of the results.

[0078] The present invention also provides a friction plate pressure distribution simulation evaluation system, which is applied to the above-mentioned pressure distribution simulation evaluation method, such as Figure 6 Shown, including:

[0079] Model setting module 1, used to set the parameters of each component in the simulation model of the braking system and the connection relationship between the components;

[0080] Condition setting module 2, used to set the boundary conditions and loads of the simulation model and then start the simulation;

[0081] Calculation module 3, used to calculate the coefficient of variation value for evaluating the contact pressure of each friction plate based on the contact pressure results obtained by simulation;

[0082] The evaluation module 4 is connected to the calculation module 3 and is used to repeatedly execute the model setting module 1, the condition setting module 2 and the calculation module 3, and adjust the parameters set in the model setting module during each repetition, and compare all the coefficient of variation values to compare the uniformity of the surface contact pressure distribution of different friction plates.

[0083] In a preferred embodiment of the present invention, a model pre-processing module 5 is further included, connected to the model setting module 1, for deleting the chamfers of the friction plate, the oil inlet hole of the brake caliper, and the chamfers of the bolt holes in the simulation model.

[0084] In a preferred embodiment of the present invention, the components in the simulation model include a brake disc, a friction plate, a brake bracket, a brake caliper, a piston and a guide pin.

[0085] In a preferred embodiment of the present invention, the model setting module 1 includes:

[0086] A mesh division unit 11 is used to perform mesh division on each component in the simulation model;

[0087] A surface contact setting unit 12 is used to set the connection relationship between the brake disc and the friction plate, the clamping claw of the brake caliper and the outer friction plate, the piston and the inner friction plate, the guide pin and the brake bracket, and the guide pin and the brake caliper to surface contact;

[0088] The binding contact setting unit 13 is used to set the connection relationship between the friction material, the steel back and the silencer plate inside the friction plate to binding contact, and to set the connection relationship between the bolt and the pin inside the guide pin to binding contact.

[0089] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. A friction plate pressure distribution simulation evaluation method, characterized in that: include: Step S1, setting the parameters of each component in the simulation model of the brake system and the connection relationship between the components; Step S2, setting the boundary conditions and loads of the simulation model and then starting the simulation; Step S3, calculating a coefficient of variation of the contact pressure of the friction plate based on the contact pressure result obtained by simulation; Step S4, repeatedly executing steps S1-S3 multiple times, and adjusting the parameters set in step S1 during each repetition, and comparing all the coefficient of variation values to compare the uniformity of the surface contact pressure distribution of different friction plates.

2. The friction plate pressure distribution simulation evaluation method according to claim 1, characterized in that: Before executing step S1, the simulation model is preprocessed, including deleting the friction plate chamfer, the brake caliper oil inlet hole and the bolt hole chamfer in the simulation model.

3. The pressure distribution simulation evaluation method according to claim 1, characterized in that: The components in the simulation model include a brake disc, a friction plate, a brake bracket, a brake caliper, a piston and a guide pin.

4. The pressure distribution simulation evaluation method according to claim 3, characterized in that: The step S1 comprises: Step S11, meshing each component in the simulation model and setting parameters; Step S12, setting the connection relationship between the brake disc and the friction plate, the clamping claw of the brake caliper and the outer friction plate, the piston and the inner friction plate, the guide pin and the brake bracket, and the guide pin and the brake caliper to surface contact; Step S13, setting the connection relationship between the friction material inside the friction plate, the steel back and the silencer plate to a binding contact, and setting the connection relationship between the bolt inside the guide pin and the pin to a binding contact.

5. The pressure distribution simulation evaluation method according to claim 3, characterized in that: The step S2 comprises: Step S21, applying pressure to the piston and the cylinder bottom surface of the brake caliper to simulate real hydraulic pressure; Step S22: applying a rotation speed to the brake disc through the keyword Motion to set the rotation axis and reference point of the brake disc.

6. The pressure distribution simulation evaluation method according to claim 1, characterized in that: The step S3 comprises: Step S31, obtaining a contact pressure cloud map obtained by simulation, and obtaining a unit pressure value of each unit in the contact pressure cloud map as the contact pressure result; Step S32: Calculate the coefficient of variation based on the unit pressure values of all units.

7. A friction plate pressure distribution simulation evaluation system, characterized in that: The pressure distribution simulation evaluation method according to any one of claims 1 to 6 comprises: A model setting module is used to set the parameters of each component in the simulation model of the braking system and the connection relationship between the components; A condition setting module, used to set boundary conditions and loads for the simulation model before starting simulation; A calculation module, configured to calculate a coefficient of variation value for evaluating the contact pressure of each friction plate based on the contact pressure results obtained by simulation; An evaluation module is connected to the calculation module and is used to repeatedly execute the model setting module, the condition setting module and the calculation module, and adjust the parameters set in the model setting module during each repetition, and compare all the coefficient of variation values to compare the uniformity of the surface contact pressure distribution of different friction plates.

8. The friction plate pressure distribution simulation evaluation system according to claim 7, characterized in that: It also includes a model preprocessing module, which is connected to the model setting module and is used to delete the chamfers of the friction plate, the oil inlet hole of the brake caliper and the chamfers of the bolt hole in the simulation model.

9. The pressure distribution simulation evaluation system according to claim 7, characterized in that: The components in the simulation model include a brake disc, a friction plate, a brake bracket, a brake caliper, a piston and a guide pin.

10. The pressure distribution simulation evaluation system according to claim 9, characterized in that: The model setting module includes: A mesh division unit, used for performing mesh division on each component in the simulation model; a surface contact setting unit, for setting the connection relationship between the brake disc and the friction plate, the clamping claw of the brake caliper and the outer friction plate, the piston and the inner friction plate, the guide pin and the brake bracket, and the guide pin and the brake caliper to surface contact; The binding contact setting unit is used to set the connection relationship between the friction material, steel back and silencer plate inside the friction plate to binding contact, and set the connection relationship between the bolt and pin inside the guide pin to binding contact.

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