Friction material rough surface contact model construction method based on measured data

Abstract

The invention belongs to the technical field of tribology of an automobile transmission system, and provides a friction material rough surface contact model construction method based on actually measured data, which comprises the following steps: acquiring rough peak height distribution characteristics, total distance and actual contact area of a nominal surface of a friction material, fitting the rough peak height distribution characteristics to obtain a probability density function, and calculating a friction material rough surface contact model; integrating to obtain a function relationship between the distance between the friction pairs and the number of contact rough peaks, and deducing a calculation formula of a scaling factor; according to the obtained actual contact area and the total distance, a function relation between the actual contact area and the total distance is established, so that a first function relation between the actual contact area and the distance between the friction pairs is obtained, and finally the actual contact area and the contact pressure intensity are expressed as a function of the distance between the friction pairs. The technical problems that in high-fidelity simulation of a transmission system, a clutch model is insufficient in precision, and the actual contact area and the contact pressure intensity of a rough peak of a friction material in a mixed lubrication state are difficult to accurately determine can be solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of tribology of automobile transmission system, and provides a rough surface contact model construction method of friction material based on measured data. BACKGROUND

[0002] The performance optimization of the transmission system increasingly relies on high-fidelity system simulation, and the core goal is to evaluate the driving performance and shift quality in advance to provide accurate reference for product development. The clutch is a key component of the transmission model, and the accuracy of its dynamic characteristic simulation directly determines the reliability of the entire transmission system simulation.

[0003] In the engagement process of the wet clutch, it will go through fluid lubrication, mixed lubrication to boundary lubrication three stages, among which the mixed lubrication state is a typical scenario in the field of tribology. Due to insufficient load, speed or lubricant viscosity, a complete lubrication film cannot be formed, resulting in direct contact of the rough peaks on the surface of the friction pair. At this time, the load on the surface of the friction pair is borne by two parts: one is the part of the load borne by the lubrication film (the oil film formed by hydrodynamic or elastohydrodynamic lubrication); the other is the remaining load borne by the surface microconvex body (rough peak) in direct contact. The actual contact area of the friction pair under the action of the normal load (i.e. the total micro area of the rough peak contact spots) and the actual contact pressure at the contact area are the core parameters for accurately describing this process, and the determination of these parameters has long been a problem that restricts the prediction accuracy of the clutch torque transmission behavior.

[0004] To solve the above problems, the existing technology mainly adopts the following schemes: one is to establish a rough surface contact model by theoretical assumption, and a Gaussian distribution is generally used to describe the height distribution of the nominal surface microconvex body of the friction material, and the number of rough peaks participating in the contact is estimated based on the distribution; two is to determine the relationship between the actual contact area and the contact pressure by empirical method, for example, assuming that there is a linear correlation between the nominal contact area and the actual contact area, and introducing an empirical coefficient to correct the calculation of the rough interface pressure; three is to combine a simplified lubrication film model to combine the contact parameters with the fluid dynamics model to realize the simulation of the engagement process of the clutch.

[0005] However, the existing technology has the following significant defects, and these defects are the technical problems that can be solved by the present application: Inaccurate description of rough peak height distribution: after actual running-in of the friction material, the height distribution of the surface microconvex body presents obvious asymmetry, while the Gaussian distribution used in the existing technology can only fit the symmetric distribution characteristics, resulting in large deviation in the evaluation of the number of contact peaks, which directly affects the calculation accuracy of the actual contact area.

[0006] Lack of actual data support: the existing model relies on theoretical assumptions and empirical coefficients, and does not combine the actual working condition of the friction material nominal surface characteristic measured data, the subjectivity and uncertainty of the empirical coefficient make the contact pressure and the actual contact area lack of credibility, and the contact behavior of the friction material under the real load cannot be reflected.

[0007] Inaccurate quantitative relationship modeling: the existing technology fails to establish a clear quantitative function relationship among the actual contact area, the contact surface pressure and the distance between the friction pair, resulting in a large deviation between the simulation results and the actual working condition, which is difficult to meet the demand of high-fidelity simulation of the transmission system, and restricts the accuracy of the shift quality evaluation. SUMMARY

[0008] In order to solve the above technical problems, the present application provides a rough surface contact model construction method of friction material based on measured data, which solves the technical problems of insufficient precision of clutch model in high-fidelity simulation of transmission system, and difficulty in accurately determining the actual contact area and contact pressure of rough peak of friction material under mixed lubrication state, and can truly restore the contact behavior of friction material under load, realize higher precision numerical modeling and shift simulation.

[0009] The technical scheme of the present application includes: Obtaining a plurality of groups of rough peak height distribution characteristics of the nominal surface of the friction material, the total distance between the detection surface and the friction material placing desktop under different loads And the actual contact area of the detection surface and the friction material under different loads .

[0010] The probability density function is obtained by fitting a plurality of groups of rough peak height distribution characteristics, and the probability density function is represented by the kernel distribution function Under the condition of given distance Between the friction pairs, the probability density function Is integrated to obtain the functional relationship between the distance Between the friction pairs and the number N of contacted rough peaks.

[0011] According to the relationship between the total distance Under any two loads and the distance Between the friction pairs, the calculation formula of the scaling factor Is obtained.

[0012] According to the obtained actual contact area And the total distance , the functional relationship between the actual contact area And the total distance Is established, and the calculation formula of the scaling factor Is combined to obtain the actual contact area And the distance The function relationship one.

[0013] The actual contact area based on the load condition The actual contact area is obtained by increasing the number of rough peaks N in contact with the detection surface in proportion and normalizing the number of rough peaks N. The actual contact area is equal to the number of rough peaks N, and then the distance between the friction pairs The function relationship of the number of rough peaks N in contact and the function relationship one are combined with the contact pressure The actual contact area is obtained The function relationship two of the distance between the friction pairs The function relationship of the contact pressure The function relationship of the distance between the friction pairs The contact pressure The actual contact area The actual contact area is equal to the nominal contact area .

[0014] According to the function relationship two of the actual contact area The function relationship of the distance between the friction pairs The function relationship of the contact pressure The function relationship of the distance between the friction pairs The friction material rough surface contact model is constructed.

[0015] Further, the friction material is a wet friction plate after running-in cycle.

[0016] Further, when obtaining a plurality of groups of rough peak height distribution characteristics, at least 8 radial directions and at least 14 circumferential directions on the nominal surface of the friction material are measured respectively.

[0017] Further, the probability density function is represented by a kernel function As follows: ; In the formula, is the sample size of the rough peak height distribution characteristic, is the height of the rough peak, is a single sample extracted from the rough peak height distribution, is a kernel smoothing function, is the bandwidth, and the value is 1.17.

[0018] Further, the function relationship of the distance between the friction pairs The number of rough peaks N in contact is: ; In the formula, indicates the number of rough peaks, to are the fitting coefficients respectively.

[0019] Further, the calculation formula of the scaling factor is: For any two load conditions and , where , the relationship of the inter-friction pair distance is: ; ; In the formula, represents the inter-friction pair distance under the load condition , represents the total distance under the load condition , represents the nominal thickness of the friction material under the load condition , represents the inter-friction pair distance under the load condition , represents the total distance under the load condition , and represents the nominal thickness of the friction material under the load condition .

[0020] According to the condition that the thickness change rate is uniformly changed throughout the friction material, we obtain: ; In the formula, , ; The scaling factor is defined as: ; According to the above formula and the relationship of the scaling factor , we obtain: .

[0021] Further, the functional relationship between the actual contact area and the total distance is: ; In the formula, B1 to B5 are coefficients.

[0022] Further, the functional relationship between the actual contact area and the inter-friction pair distance is: .

[0023] Further, the functional relationship between the actual contact area​​​​​ Distance between friction pairs The second functional relationship is: ; The contact pressure Distance between friction pairs The functional relationship is as follows: ; In the formula, to and to All of these are coefficients.

[0024] Furthermore, the scaling factor The method for determining the value is as follows: Based on the actual contact area under different loads The condition that the change is proportional to the change in the actual number of rough peaks N in contact is met. .

[0025] The height of the micro-protrusions on the surface above Integrating, where and Take the maximum and minimum values ​​of the gap between the separation plate and the friction material respectively.

[0026] Convert Δ to A function, namely: in to These are the coefficients for each item; By obtaining The zeros of the equation determine the scaling factor. Values.

[0027] The technical solution provided by this invention has the following advantages compared with the prior art: This invention accurately describes the asymmetric height distribution of micro-protrusions by combining measured data with kernel distribution, and establishes a functional relationship between actual contact area, contact surface pressure and friction pair distance. Compared with the traditional Gaussian distribution, it significantly improves the accuracy of contact parameter evaluation, can realistically reproduce the contact behavior of friction materials under load, and achieves higher precision numerical modeling and shift simulation. It can provide support for early evaluation of driving and shifting performance of wet clutches in transmissions, and can also be widely applied to dry clutches, brakes and other fields, with strong scalability.

[0028] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 The 22 trajectories in this embodiment of the invention are fitted as rough peak height distribution characteristic curves.

[0031] Figure 2 This is a schematic diagram of the relevant parameters of the rough surface contact model in an embodiment of the present invention.

[0032] Figure 3 This is a model diagram of the rough surface of the friction material in an embodiment of the present invention.

[0033] Figure 4 This is a curve showing the relationship between the contact pressure and the actual contact area on a rough surface in an embodiment of the present invention. Figure 1 .

[0034] Figure 5 This is a graph showing the relationship between the actual contact area and the total distance in an embodiment of the present invention.

[0035] Figure 6 This is a curve showing the relationship between the contact pressure and the actual contact area on a rough surface in an embodiment of the present invention. Figure 2 .

[0036] Figure 7 This is a graph showing the relationship between the contact pressure on the rough surface and the distance between the friction pairs in an embodiment of the present invention.

[0037] Figure 8 This is a graph showing the relationship between the actual contact area and the distance between the friction pairs in an embodiment of the present invention. Detailed Implementation

[0038] The following detailed description of a specific embodiment of the present invention is provided in conjunction with the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.

[0039] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] In the description of the embodiments of the present invention, unless otherwise stated, "a plurality of" means two or more.

[0041] In the description of the embodiments of the present invention, the distance between friction pairs is also the distance between the friction plate and the separation plate (prism).

[0042] This invention provides a method for constructing a contact model of a rough surface of a friction material based on measured data, comprising: Obtain the height distribution characteristics of several sets of roughness peaks on the nominal surface of the friction material, and the total distance between the test surface and the table where the friction material is placed under different loads. and the actual contact area between the test surface and the friction material under different loads. .

[0043] The probability density function is obtained by fitting several sets of rough peak height distribution characteristics. The probability density function is then used with the kernel distribution function. Let this represent the distance between a given friction pair. Under the condition of probability density function Integrating, we obtain the distance between the friction pairs. The relationship between the number of rough peaks N in contact and the friction pair distance. Note the relationship between the friction pair distance and the friction pair distance. =Total distance -Nominal thickness of friction material .

[0044] Based on the total distance under any two loads Distance between friction pairs The relationship is used to obtain the scaling factor. The calculation formula.

[0045] Based on the actual contact area Total distance Establish actual contact area Total distance The functional relationship, combined with the scaling factor The calculation formula yields the actual contact area. Distance between friction pairs Functional relationship 1.

[0046] Based on actual contact area under load conditions The number of roughness peaks N increases proportionally to the number of roughness peaks in the contact area of ​​the detection surface. Normalizing the number of roughness peaks N yields the actual contact area. The condition is equal to the number of rough peaks N, then the distance between friction pairs. The functional relationship between the number of rough peaks N in contact and the functional relationship between the contact pressure and the contact pressure are both combined. Obtain the actual contact area Distance between friction pairs The functional relationship between the second and the contact pressure Distance between friction pairs The functional relationship of the contact pressure equal to the actual contact area Compared to nominal contact area .

[0047] Based on the actual contact area Distance between friction pairs The functional relationship between the second and the contact pressure Distance between friction pairs The functional relationship is used to construct a contact model of the rough surface of the friction material.

[0048] The height distribution characteristics of several sets of roughness peaks on the nominal surface of the friction material were measured using a profilometer. The profilometer probe employed a 60-degree conical diamond tip with a tip radius of 2 micrometers. During the measurement, a force of 0.75 millinewtons was applied vertically, and the probe moved horizontally, passing through the roughness peaks on the friction material. Its vertical motion was recorded as an electrical signal, which was then post-processed and digitized for statistical analysis of the roughness height distribution. The nominal surface was used as the reference plane during measurement to ensure that the average value of the measured values ​​was 0.

[0049] Total distance between the detection surface and the friction material placed on the table under different loads and the actual contact area between the test surface and the friction material under different loads. The parameters obtained through measurement using a 3D topography testing instrument are as follows: Figure 2 and Figure 3 As shown.

[0050] Contact pressure equal to the actual contact area Compared to nominal contact area The basis is: Torque transmitted by a wet clutch Torque is generated by the shearing of viscous fluid in the lubricating film. Torque generated by contact with micro-protrusions Shared responsibility: .

[0051] The pressure applied by the clutch Pressure is generated by the viscous fluid in the lubricating film. Pressure generated by contact with surface micro-protrusions sum: .

[0052] Fluid torque in the lubricating film It can be obtained by integrating the shear stress in the fluid: .

[0053] Pressure generated by viscous fluid With the thickness of the lubricating film The relationship can be expressed by the Reynolds equation: .

[0054] In the equation above, η represents the dynamic viscosity of the fluid. For radius, For rotational speed, for and The function, This represents the nominal contact area of ​​the friction surface.

[0055] The torque transmitted in the contact of the micro-assemblage is solved using Coulomb friction, as shown in the equation. .

[0056] A widely accepted method for calculating pressure at rough interfaces The method is based on the actual contact area, assuming a nominal contact area. actual contact area There is a linear relationship between the two, as shown in the equation. .

[0057] like Figure 4 and Figure 5 The diagram illustrates the relationship between the contact area and the applied load, as well as the distance the prism probe (i.e., the prism surface as the detection surface) moves. By recording the displacement of the measuring probe during the application of a load to the friction material, the distance between the prism probe and the table can be calculated. Because the friction material is compressible, the distance between the prism surface and the nominal surface of the friction material... It cannot be measured directly, only by distance. Calculate distance .

[0058] In the embodiments provided by the present invention, the friction material is a wet friction plate after a break-in cycle, preferably a wet friction plate after 200 break-in cycles.

[0059] In the embodiments provided by the present invention, when obtaining multiple sets of the rough peak height distribution characteristics, measurements are taken at least 8 radial directions and at least 14 circumferential directions on the nominal surface of the friction material.

[0060] like Figure 1 As shown, 22 tracks measured in 8 radial directions and 14 axial directions are fitted to a characteristic distribution curve of roughness peak height. Positive values ​​on the lateral coordinate represent convexities above the nominal surface, while negative values ​​represent depressions. The distribution of each track is very similar, with a highly concentrated height distribution, and the maximum roughness peak height is approximately 20 micrometers. Overall, the distribution shape exhibits a significant asymmetry, which can be fully described by the kernel distribution.

[0061] Furthermore, the probability density function is derived from the kernel function. Represented as: ; In the formula, The sample size represents the characteristic of the rough peak height distribution. The height of the rough peak. This is a single sample drawn from the rough peak height distribution. For kernel smoothing function, For bandwidth, the value is 1.17.

[0062] In the embodiments provided by the present invention, when the wet clutch is engaged, the distance between the friction pair between the prism probe and the friction material increases. As the probability density function decreases, more and more surface roughness peaks begin to contact each other. The integral area below represents the area under a given friction pair spacing. Below, the total number of rough peaks involved in the contact (Normalization) is expressed as: ; In the formula, Indicates the number of rough peaks. to The coefficients obtained from the fitting are respectively plotted based on the actual measured data, and the fitted curve equation is obtained by integration.

[0063] With the friction pair spacing The number of contact peaks decreases continuously. As the number of contacts increases, the accuracy of assessing the number of contacts in contact peaks is significantly improved compared to using the traditional Gaussian distribution.

[0064] like Figure 6 As shown, in the embodiment provided by the present invention, the scaling factor is calculated. The calculation formula is as follows: For any two load conditions and ,in The distance between the friction pairs The relationship is: ; ; In the formula, Indicates under load conditions The distance between the friction pairs, Indicates under load conditions Total distance, Indicates under load conditions The nominal thickness of the friction material, Indicates under load conditions The distance between the friction pairs, Indicates under load conditions Total distance, Indicates under load conditions The nominal thickness of the friction material.

[0065] Deformation of the friction material structure affects the overall thickness Not sensitive, more specifically, to the distance between friction pairs. and Since the ratio is insensitive, the thickness change rate can be considered uniform across the entire friction material, resulting in the following linear equation: ; In the formula, , ; Define scaling factor : ; Based on the above formula and scaling factor The relationship yields: .

[0066] The scaling factor, used to determine the effective thickness relative to the friction material, can also be calculated using the results of joint surface profile measurements and contact area measurements.

[0067] In the embodiments provided by the present invention, the scaling factor The method for determining the value is as follows: Based on the actual contact area under different loads The condition that the change is proportional to the change in the actual number of rough peaks N in contact is met. .

[0068] The height of the micro-protrusions on the surface above Integrating, where and Take the maximum and minimum values ​​of the gap between the separation plate and the friction material respectively.

[0069] Convert Δ to A function, namely: in to For each coefficient, a curve was plotted based on the actual measured data, the curve equation was fitted, and then integrated. By obtaining The zeros of the equation determine the scaling factor. Values.

[0070] In the embodiments provided by the present invention, the actual contact area It is contact pressure Total distance A function that can be used Figure 6 The actual contact area is obtained from the curve in the graph. Total distance The functional relationship is as follows: ; In the formula, B1 to B5 are the coefficients of each item, which are obtained by plotting curves based on actual measured data, fitting the curve equation, and integrating.

[0071] In the embodiments provided by the present invention, a scaling factor is incorporated. The calculation formula for the actual contact area is used. Distance between friction pairs The first functional relationship is: .

[0072] In the embodiments provided by the present invention, based on the actual contact area under different loads... The condition that the change is proportional to the change in the actual number of rough peaks N in contact is met. .

[0073] The actual contact area Distance between friction pairs The functional relationship is expressed as follows: ; The contact pressure Distance between friction pairs The functional relationship is as follows: ; In the formula, to and to All of these are coefficients, obtained by plotting curves based on actual measured data, fitting curve equations, and integrating them.

[0074] That is, the actual contact area Distance between friction pairs The functional relationship between the second and the contact pressure Distance between friction pairs The functional relationship is the model function obtained in this invention. The two formulas form a rough surface contact model, which represents the characteristics of the friction material actually used. Figure 7 and Figure 8 This is reflected in the two curves.

[0075] In practical use, the rough surface contact model of this invention only requires measuring the total distance using an instrument. and the nominal thickness of friction materials Obtain the actual contact area and contact pressure This allows for a more accurate representation of the contact behavior of friction materials under load, enabling higher-precision numerical modeling and gear shifting simulation.

[0076] The rough surface contact model involved in this invention can be used in conjunction with other fluid dynamics models. It can be used for rapid modeling of one-dimensional clutch models, for high-precision clutch simulation, and can also be used in conjunction with detailed three-dimensional CFD simulations.

[0077] It should be noted that any parts not disclosed or specifically described in this invention are existing technology or conventional configurations, and their specific structures and working principles will not be elaborated further. In this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0078] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the invention. Other modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the invention is not limited to the specific details and examples shown and described herein.

Claims

1. A method for constructing a contact model of a rough surface of a friction material based on measured data, characterized in that, include: Obtain the height distribution characteristics of several sets of roughness peaks on the nominal surface of the friction material after actual break-in, and the total distance between the test surface and the table where the friction material is placed under different loads. and the actual contact area between the test surface and the friction material under different loads. ; The probability density function is obtained by fitting several sets of rough peak height distribution characteristics. The probability density function is then used with the kernel distribution function. Let represent the distance between a given friction pair. Under the condition of probability density function Integrating, we obtain the distance between the friction pairs. The functional relationship between the number of rough peaks N in contact and the contact surface; Based on the total distance under any two loads Distance between friction pairs The relationship is used to obtain the scaling factor. The calculation formula; Based on the actual contact area Total distance Establish actual contact area Total distance The functional relationship, combined with the scaling factor The calculation formula yields the actual contact area. Distance between friction pairs Functional relationship one; Based on actual contact area under load conditions The number of roughness peaks N increases proportionally to the number of roughness peaks in the contact area of ​​the detection surface. Normalizing the number of roughness peaks N yields the actual contact area. The condition is equal to the number of rough peaks N, then the distance between friction pairs. The functional relationship between the number of rough peaks N in contact and the functional relationship between the contact pressure and the contact pressure are both combined. To obtain the actual contact area Distance between friction pairs The functional relationship between the second and the contact pressure Distance between friction pairs The functional relationship of the contact pressure Equal to actual contact area Compared to nominal contact area ; Based on the actual contact area Distance between friction pairs The functional relationship between the second and the contact pressure Distance between friction pairs The functional relationship is used to construct a contact model of the rough surface of the friction material.

2. The method for constructing a contact model of a rough surface of a friction material based on measured data as described in claim 1, characterized in that, When obtaining multiple sets of the rough peak height distribution characteristics, measurements are taken at least 8 radial directions and at least 14 circumferential directions on the nominal surface of the friction material.

3. The method for constructing a contact model of a rough surface of a friction material based on measured data as described in claim 1, characterized in that, The probability density function is derived from the kernel function. Represented as: ； In the formula, The sample size represents the characteristic of the rough peak height distribution. The height of the rough peak. This is a single sample drawn from the rough peak height distribution. For kernel smoothing function, For bandwidth, the value is 1.

17.

4. The method for constructing a contact model of a rough surface of a friction material based on measured data as described in claim 3, characterized in that, Distance between friction pairs The functional relationship between the number of rough peaks N in contact and the following is: ； In the formula, Indicates the number of rough peaks. to All of these are coefficients, obtained by plotting curves based on actual measured data, fitting curve equations, and integrating them.

5. The method for constructing a contact model of a rough surface of a friction material based on measured data as described in claim 1, characterized in that, Calculate the scaling factor The calculation formula is as follows: For any two load conditions and ,in The distance between the friction pairs The relationship is: ； ； In the formula, Indicates under load conditions The distance between the friction pairs, Indicates under load conditions Total distance, Indicates under load conditions The nominal thickness of the friction material, Indicates under load conditions The distance between the friction pairs, Indicates under load conditions Total distance, Indicates under load conditions The nominal thickness of the friction material; Based on the condition that the thickness change rate varies uniformly across the entire friction material, we obtain: ； In the formula, , ; Define scaling factor : ； Based on the above formula and scaling factor The relationship yields: 。 6. The method for constructing a contact model of a rough surface of a friction material based on measured data as described in claim 5, characterized in that, The actual contact area Total distance The functional relationship is as follows: ； In the formula, B1 to B5 are all coefficients, which are obtained by plotting curves based on actual measured data, fitting the curve equations, and integrating.

7. The method for constructing a contact model of a rough surface of a friction material based on measured data as described in claim 6, characterized in that, The actual contact area Distance between friction pairs The first functional relationship is: 。 8. The method for constructing a contact model of a rough surface of a friction material based on measured data as described in claim 7, characterized in that, The actual contact area Distance between friction pairs The second functional relationship is: ； The contact pressure Distance between friction pairs The functional relationship is as follows: ； In the formula, to and to All of these are coefficients, obtained by plotting curves based on actual measured data, fitting curve equations, and integrating them.

9. The method for constructing a contact model of a rough surface of a friction material based on measured data as described in claim 8, characterized in that, The scaling factor The method for determining the value is as follows: Based on the actual contact area under different loads The condition that the change is proportional to the change in the actual number of rough peaks N in contact. ; For the height of the micro-protrusions on the surface of the above formula Integrating, where and Take the maximum and minimum values ​​of the gap between the separation plate and the friction material, respectively; Convert Δ to A function, namely: in to All of these are coefficients, obtained by plotting curves based on actual measured data, fitting curve equations, and integrating them. By obtaining The zeros of the equation determine the scaling factor. Values.

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