Wide-speed-range no-load wet clutch driving torque suppression optimization method

Abstract

The invention relates to a wide-speed-range no-load wet clutch belt row torque restraining optimization method which comprises the steps that 1, an initial curve groove profile line is obtained, 2, a new curve groove profile line is constructed based on the initial curve groove profile line, and the deviation angle of discrete points of the new curve groove profile line in the circumferential direction and friction plate oil groove structure parameters serve as design variables; designing an optimization target of the driving torque of the wide-speed-range no-load wet clutch, and establishing a constraint condition corresponding to the optimization target; 3, assigning the design variables, generating a design space of a plurality of groups of test sample points, establishing an approximate model by adopting an elliptic basis neural network model in combination with constraint conditions, and obtaining an optimal solution of search parameter optimization in the design space; and 4, respectively inputting the optimal solution of the search parameter optimization in the design space into the fluid-solid coupling rub-impact dynamic model and the low-speed viscous tape displacement torque model, and obtaining the optimal result of the parameter optimization of the friction pair of the wide-speed-range no-load wet clutch under the high-speed and low-speed working conditions.

Description

Technical Field

[0001] The invention relates to the technical field of clutch torque suppression optimization, and in particular to a method for optimizing clutch torque suppression over a wide speed range. Background Art

[0002] The existence of the wet clutch displacement torque consumes engine power and reduces the efficiency of the transmission system. However, due to the need for lubrication, the displacement torque phenomenon cannot be avoided.

[0003] At low speeds, a wet clutch will generate a viscous shear displacement torque, causing power loss in the clutch and reducing the efficiency of the vehicle's transmission system. At high speeds, there will be frequent frictional movements of the friction pair, which will generate frictional displacement torque, causing a sharp increase in the heat generated by the high-speed clutch, and may even lead to high-temperature carbonization of the lubricating oil and thermal damage to the friction plate, making the clutch unable to work normally.

[0004] At present, there have been relevant theoretical studies on the analysis of oil groove characteristics on the clutch friction plate surface and the optimization of the belt displacement torque at home and abroad. However, they focus on the influence of regular-shaped oil grooves on low-speed belt displacement torque and the comparison of belt displacement torque under different groove types. There is a lack of a more general oil groove shape optimization design method that can achieve low belt displacement torque over a wide speed range. Summary of the invention

[0005] In response to the above-mentioned problems, the present invention established a parametric modeling method for the oil groove profile of the friction plate surface, and obtained an optimized design model for the oil groove on the friction plate surface based on the fluid-solid coupling friction dynamics model of the friction pair, which can achieve optimized design of the oil groove on the friction plate surface with the goal of reducing the belt displacement torque within a wide speed range.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A method for optimizing the torque suppression of a no-load wet clutch with a wide speed range, comprising:

[0008] Step 1: Get the initial curve groove shape line.

[0009] Step 2: construct a new curved groove profile based on the initial curved groove profile, use the circumferential offset angle of the discrete points of the new curved groove profile and the friction plate oil groove structural parameters as design variables, design an optimization target for the unloaded wet clutch with displacement torque in a wide speed range, and establish constraint conditions corresponding to the optimization target;

[0010] Step 3, assigning values ​​to the design variables to generate a design space of several groups of test sample points, using an elliptic basis neural network model combined with the constraint conditions to establish an approximate model, and obtaining the optimal solution for parameter optimization in the design space;

[0011] Step 4: input the optimal solution of parameter optimization searched in the design space into the fluid-solid coupling friction dynamics model and the belt displacement torque model respectively to obtain the optimal result of friction pair parameter optimization of the no-load wet clutch in a wide speed range under low-speed and high-speed conditions.

[0012] Optionally, obtaining the initial curved groove profile line includes:

[0013] Obtaining a plurality of first discrete points, and obtaining a cubic spline interpolation polynomial according to the plurality of first discrete points;

[0014] Natural boundary conditions are set, the second-order derivative matrix of the interpolation function in the cubic spline interpolation polynomial is calculated, the coefficients of each term of the cubic spline interpolation polynomial are determined, and the initial curved groove shape line is obtained.

[0015] Optionally, constructing a new curved groove profile line based on the initial curved groove profile line comprises:

[0016] Taking the initial curved groove shape line as the initial shape line, selecting a number of second discrete points equidistantly radially on the initial shape line;

[0017] The circumferential coordinates of the second discrete points are adjusted in angle to obtain new discrete points, and an optimal shape line is further generated. According to the optimal shape line, a new groove form is obtained, that is, the optimization problem of the initial curved groove shape line is converted into a numerical optimization problem of the parameters of the initial groove and the axial angle offset matrix.

[0018] Optionally, the optimization objectives of designing the wide-speed range no-load wet clutch with displacement torque include:

[0019] The viscous shear peak displacement torque of the wide-speed range no-load wet clutch under low-speed conditions and the total displacement torque at the highest operating speed are taken as optimization targets.

[0020] Optionally, establishing constraint conditions corresponding to the optimization target includes:

[0021] The viscous shear peak displacement torque under the low speed condition and the minimum total displacement torque under the highest operating speed are set as optimization objectives:

[0022] minf(X)=(T s ,T)

[0023] Among them, minf(X) is the optimization target, T s is the displacement torque of the wet clutch at low speed, and T is the displacement torque of the wet clutch at high speed.

[0024] Optionally, the method for obtaining the displacement torque of the wet clutch at low speed is:

[0025]

[0026] Among them, T si is the average value of the sum of displacement moments of the viscous shear bands of each friction pair, and t is the simulation time;

[0027] The method for obtaining the average value of the sum of the displacement moments of the viscous shear bands of the friction pairs is:

[0028]

[0029] Among them, r e is the full film lubrication equivalent radius, r i is the inner radius of the single-plate wet clutch (mm), r o is the outer radius of the single-plate wet clutch (mm), τ θ is the internal friction force per unit area of ​​the oil film area (full film lubrication area), θ is the angle relative to the central axis of the clutch, τ θz is the internal friction force per unit area outside the oil film area.

[0030] Optionally, the belt displacement torque of the wet clutch at high speed includes: the viscous shear belt displacement torque and the friction belt displacement torque of the lubricating oil;

[0031] The method for obtaining the friction belt displacement torque is:

[0032]

[0033] Where e is the coefficient of restitution, is the Hertz contact stiffness coefficient, λ is the plastic stiffness coefficient, δ, are the relative speed and relative displacement of the steel plate and the friction plate, is the residual plastic deformation, δ m is the maximum relative displacement, f i is the collision friction, r o is the outer radius of the single-plate clutch, w is the speed difference between the steel plate and the friction plate, w r is the critical speed of clutch collision, v is the Poisson's ratio of the material, k is the material stiffness coefficient, R1 is the steel plate contact radius, R2 is the friction plate contact radius, k1 is the steel plate stiffness coefficient, and k2 is the friction plate stiffness coefficient.

[0034] Optionally, obtaining the optimal solution for searching parameter optimization in the design space includes:

[0035] Obtaining the optimal solution for parameter optimization in the design space is divided into two stages:

[0036] With (N g ,h g , δ c ,δ r) This set of friction plate oil groove structural parameters is used as the design variables in the first stage, where N g is the number of oil tanks, h g is the oil groove depth, δ c =θ g / θ p The circumferential groove-to-platform ratio, δ, characterizes the groove width r =(r g -r i ) / (r o -r i ) characterizes the radial groove-dam ratio which is the ratio of the inner and outer radius of the groove area to the inner and outer radius of the friction plate, assigns values ​​to the design variables of the first stage, generates the design space of the first stage for several groups of test sample points, adopts the elliptic basis neural network model combined with the constraint conditions, establishes the approximate model of the first stage, and obtains the optimal solution for searching the optimization parameters in the design space of the first stage;

[0037] The optimal solution of parameter optimization search in the design space of the first stage is combined with the circumferential offset angle of discrete points on the groove shape line as the design variables of the second stage. The elliptical basis neural network model is combined with the constraints to establish an approximate model of the second stage to obtain the optimal solution of parameter optimization search in the design space of the second stage.

[0038] Optionally, obtaining the optimal result of the friction pair parameter optimization of the wide speed range no-load wet clutch under low speed and high speed conditions includes:

[0039] The optimal solution of parameter optimization searched in the design space is input into the fluid-solid coupling friction dynamics model and the belt displacement torque model respectively, so as to obtain the optimization results to be verified for the friction pair parameter optimization of the no-load wet clutch in a wide speed range under low-speed and high-speed conditions;

[0040] Substituting the random solutions of the design variables into the input fluid-solid coupling friction dynamics model and the belt displacement torque model to obtain random optimization results;

[0041] The random optimization result is compared with the optimization result to be verified. If the random optimization result is the optimal result, steps S3-S4 are repeated to establish the approximate model until the optimization result to be verified is the optimal result. If the optimization result to be verified is the optimal result, the optimization result to be verified is output, that is, the optimal result of the optimization of the friction pair parameters of the wide speed range no-load wet clutch under low-speed and high-speed conditions is obtained.

[0042] The beneficial effects of the present invention are:

[0043] On the one hand, the present invention proposes belt displacement torque calculation models at low speed and high speed respectively, and based on this, optimizes the design of generalized irregular oil groove lines within a wide speed range; on the other hand, in the process of solving the optimization model, the experimental design method is used to reasonably plan the test samples to effectively reduce the number of simulation tests of complex systems, and the method of constructing approximate models is used to reduce the amount of calculation and improve the calculation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0045] Figure 1 A schematic diagram of a method for generating a groove optimal shape line according to an embodiment of the present invention;

[0046] Figure 2 It is a schematic flow chart of a method for optimizing the torque suppression of a no-load wet clutch with a wide speed range according to an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of a groove shape line generated by a function interpolation method according to an embodiment of the present invention;

[0048] Figure 4 Schematic diagram of optimized slot type according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] like Figure 2As shown, the present embodiment discloses a method for optimizing the suppression of the displaceable torque of a wide-speed no-load wet clutch, comprising: step 1, obtaining an initial curved groove shape line, step 2, constructing a new curved groove shape line based on the initial curved groove shape line, taking the circumferential offset angle of the discrete points of the new curved groove shape line and the friction plate oil groove structural parameters as design variables, designing the optimization target of the displaceable torque of the wide-speed no-load wet clutch, and establishing the corresponding constraint conditions of the optimization target; step 3, assigning values ​​to the design variables, generating a design space of several groups of test sample points, using an elliptical basis neural network model combined with constraint conditions to establish an approximate model, and obtaining the optimal solution for searching parameter optimization in the design space; step 4, inputting the optimal solution for searching parameter optimization in the design space into the fluid-solid coupling friction dynamics model and the displaceable torque model respectively, and obtaining the optimal results of the optimization of the friction pair parameters of the wide-speed no-load wet clutch under low-speed and high-speed conditions.

[0052] Obtaining the initial curve groove shape line includes: obtaining a number of first discrete points, and obtaining a cubic spline interpolation polynomial according to the first discrete points; setting natural boundary conditions, calculating the second-order derivative matrix of the interpolation function in the cubic spline interpolation polynomial, determining the coefficients of the cubic spline interpolation polynomial, and obtaining the initial curve groove shape line, specifically:

[0053] Step 1: Use cubic spline interpolation method to obtain the function expression of the general curved groove shape line.

[0054] Step 1.1: Select several discrete points;

[0055] Step 1.2: Use the three-moment construction method to obtain the cubic spline interpolation polynomial;

[0056] Step 1.3: Given the boundary conditions, use the three-moment equation to calculate the second-order derivative matrix of the interpolation function;

[0057] Step 1.4: Find the coefficients of the cubic spline interpolation polynomial.

[0058] Constructing a new curved groove profile based on the initial curved groove profile includes: taking the initial curved groove profile as the initial profile, selecting a number of second discrete points radially equidistantly on the initial profile; adjusting the angles of the circumferential coordinates of the second discrete points to obtain new discrete points, further generating an optimal profile, and obtaining a new groove form according to the optimal profile, that is, converting the optimization problem of the initial curved groove profile into a numerical optimization problem of the parameters of the initial groove and the axial angle offset matrix, specifically:

[0059] Step 2: Convert the optimization problem of the general curved groove shape into the parameter optimization of the initial groove and the numerical optimization problem of the axial angle offset matrix.

[0060] Step 2.1: Figure 1, select a groove shape line with better lubrication characteristics as the initial shape line.

[0061] Step 2.2: Select 4 discrete points equidistantly radially on the initial shape line.

[0062] Step 2.3: Change the circumferential coordinates of the selected four discrete points by a certain angle to obtain four new discrete points;

[0063] Step 2.4: Generate a new optimal shape line to obtain a new groove form, that is, convert the optimization problem of the general curved groove shape line into the parameter optimization of the initial groove and the numerical optimization problem of the axial angle offset matrix.

[0064] The optimization objectives for designing the unloaded wet clutch torque over a wide speed range include taking the viscous shear peak unloaded wet clutch torque under low speed conditions and the total unloaded torque under the highest operating speed as optimization objectives.

[0065] Obtaining the optimal solution for parameter optimization in the design space includes: Obtaining the optimal solution for parameter optimization in the design space is divided into two stages: (N g ,h g , δ c ,δ r ) as the design variable of the first stage, assign values ​​to the design variables of the first stage, generate the design space of the first stage for several groups of test sample points, adopt the elliptical basis neural network model in combination with the constraints, establish the approximate model of the first stage, and obtain the optimal solution for searching the optimization parameters in the design space of the first stage; take the optimal solution for searching the optimization parameters in the design space of the first stage in combination with the circumferential offset angle of the discrete points on the groove shape line as the design variable of the second stage, adopt the elliptical basis neural network model in combination with the constraints, establish the approximate model of the second stage, and obtain the optimal solution for searching the optimization parameters in the design space of the second stage, specifically:

[0066] Step 3: Using the four shape parameters and the four structural parameters of the wet clutch as design variables, the viscous shear peak displacement torque of the wet clutch under low-speed conditions and the total displacement torque at the highest operating speed are taken as optimization targets, and corresponding constraints are established to optimize the design of the general curve groove of the wet clutch.

[0067] Step 3.1: Select the optimal design parameters of the wet clutch friction pair;

[0068] Step 3.2: Set the constraints in the optimization design process;

[0069] Step 3.3: Set the peak belt displacement torque in the low speed section and the total belt displacement torque at the highest speed in the high speed section to be as small as possible as the optimization target. The objective function of the optimization problem is expressed as follows:

[0070] minf(X)=(T s ,T)

[0071] T s is the displacement torque of the wet clutch at low speed, which is generated by the viscous shear of the lubricating oil. It is obtained by calculating the arithmetic mean of the viscous shear torque at each moment in the simulation time t, that is:

[0072]

[0073] T si is the average value of the sum of displacement moments of the viscous shear bands of each friction pair, and its expression is:

[0074]

[0075] T is the displacement torque of the wet clutch at high speed, including the viscous shear displacement torque T of the lubricating oil s The friction belt displacement torque T r Two parts, T r is the average value of the sum of the friction moments of each friction pair within the simulation time t, and its expression is:

[0076]

[0077] Where e is the restitution coefficient, is the Hertz contact stiffness coefficient, λ is the plastic stiffness coefficient, δ, are the relative speed and relative displacement of the friction plate and steel plate, δ . is the residual plastic deformation, δ m is the maximum relative displacement.

[0078] Obtaining the optimal result of the friction pair parameter optimization of the wide speed domain no-load wet clutch under low-speed and high-speed conditions includes: inputting the optimal solution of the search parameter optimization in the design space into the fluid-solid coupling friction dynamics model and the belt displacement torque model respectively, and obtaining the unverified optimization result of the friction pair parameter optimization of the wide speed domain no-load wet clutch under low-speed and high-speed conditions; substituting the random solution of the design variable into the input fluid-solid coupling friction dynamics model and the belt displacement torque model to obtain the random optimization result; comparing the random optimization result with the unverified optimization result, if the random optimization result is the optimal result, repeating steps S3-S4, establishing an approximate model, until the unverified optimization result is the optimal result, if the unverified optimization result is the optimal result, outputting the unverified optimization result, that is, obtaining the optimal result of the friction pair parameter optimization of the wide speed domain no-load wet clutch under low-speed and high-speed conditions, specifically:

[0079] Step 4: Figure 2 , the belt displacement moment optimization design model is solved based on ISIGHT.

[0080] Step 4.1: Divide the optimization design variables into two groups and optimize them separately in two stages. Each stage will get the optimal solution of the selected design variables. The first stage is the optimization of the friction plate oil groove structural parameters, with (N g ,h g , δ c ,δ r ) is the design variable, and the other four optimization parameters are assigned values, among which the oil groove shape line parameter The second stage is to optimize the parameters of the friction plate groove profile, using the circumferential offset angles of the four discrete points on the groove profile. is the design variable, and the friction plate oil groove structural parameter value obtained by the first stage optimization is used as the initial value of optimization in this stage;

[0081] Step 4.1.1: Generate a design space containing 500 groups of experimental sample points using the optimal Latin hypercube method;

[0082] Step 4.1.2: Substitute each sample point into the fluid-solid coupling friction dynamics model and the belt displacement torque model in turn to obtain the response results of the objective function under different parameter combinations;

[0083] Step 4.1.3: Perform sensitivity analysis on each variable in the parameter group to determine the impact of each variable on the objective function;

[0084] Step 4.1.4: Using the elliptical basis neural network model, based on the sample data obtained from the experimental design, an approximate model of the objective function is established to describe the mathematical relationship between the friction pair parameters and the objective function;

[0085] Step 4.1.5: Use NSGA-II algorithm to search for the optimal solution for parameter optimization in the design space;

[0086] Step 4.2: Substitute the optimal solution of the design variables into the fluid-solid coupling friction dynamics model, and the optimization objective function value can be obtained according to the belt displacement moment model;

[0087] Step 4.3: Substitute the random solution of the design variable into the obtained objective function value and compare it with the objective function value obtained by the optimal solution to verify whether the optimal solution of the design variable obtained in the previous two stages is the true optimal solution;

[0088] Step 4.4: Output the optimal result of wet clutch friction pair parameter optimization.

[0089] like Figure 3 , select the number of discrete points as N points , assuming that the coordinate value of the discrete point in the cylindrical coordinate system r-θ is [r k ,θ k ],r kDistributed equally in the r direction, with an interval of Δr;

[0090] Using the three-moment construction method, the cubic spline interpolation polynomial is obtained as follows:

[0091]

[0092] Where M k YesP k The second derivative value of the point, M k =θ k ”;

[0093] Given the natural boundary conditions, the second-order derivative value of the two end points M0 = M n = 0, use the three-moment equation to calculate the second-order derivative matrix of the interpolation function:

[0094]

[0095] in:

[0096]

[0097] The coefficients of the cubic spline interpolation polynomial are obtained, and the function expression of the general curve groove shape line is obtained.

[0098] like Figure 1 , the initial shape is θ 0 =f(r) 0 , the four discrete points selected on it are Then make Change a certain angle in the θ direction The direction of r does not change, and the new coordinate point P is obtained. k ′(r k ′,θ k ′), and then interpolate the function to get the optimal shape line. The transformation relationship between the discrete points on the optimal shape line and the discrete points on the initial shape line is:

[0099]

[0100] At this point, the general curve groove shape optimization problem is transformed into the initial groove parameter optimization and circumferential angle offset matrix Numerical optimization problem.

[0101] The wet clutch is designed with displacement friction reduction. The friction pair geometric dimensions, operating parameters and design parameter constraints involved in the optimization process are shown in Table 1.

[0102] Table 1 Friction pair geometric dimensions, operating parameters and design parameter constraints

[0103]

[0104]

[0105] The errors of the elliptical basis neural network model used to simulate the relationship between the input optimization parameters and the output displacement torque are shown in Tables 2 and 3. It can be seen that the errors of the elliptical basis neural network model for simulating the input oil tank parameters and input shape parameters and the response displacement torque are far less than the allowable critical value, and the correlation coefficient is close to 1, which meets the allowable value requirements, indicating that the established approximate model has a high degree of fit and fitting accuracy with the sample point data, and can well reflect the relationship between the test factors and the response.

[0106] Table 2 Error table of elliptic basis neural network approximate model of oil tank structural parameters

[0107]

[0108] Table 3 Error table of elliptical basis neural network approximate model of slot shape parameters

[0109]

[0110] The NSGA-II multi-objective optimization algorithm is used to search and optimize the above neural network model within the constraints. The optimal solutions for the four oil groove parameters and four groove line parameters of the friction plate are shown in Table 4. In order to verify the effectiveness of the optimization design method, five groups of feasible design variables are randomly selected in the design space and compared with the optimal solution under the working conditions shown in Table 1. The results show that the friction plate belt torque with the optimal solution of the oil groove and groove line parameters is significantly smaller than the belt torque value corresponding to the random design variables. The friction plate surface geometry corresponding to the optimal solution of the oil groove and groove line parameters is shown in Figure 4 shown.

[0111] Table 4 Optimal solution verification table

[0112]

[0113]

[0114] The above embodiments are only descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for optimizing the torque suppression of a wet clutch with no-load in a wide speed range, characterized in that: include: Step 1: Get the initial curve groove shape line. Step 2: construct a new curved groove profile based on the initial curved groove profile, use the circumferential offset angle of the discrete points of the new curved groove profile and the friction plate oil groove structural parameters as design variables, design an optimization target for the unloaded wet clutch with displacement torque in a wide speed range, and establish constraint conditions corresponding to the optimization target; Step 3, assigning values ​​to the design variables to generate a design space of several groups of test sample points, using an elliptic basis neural network model combined with the constraint conditions to establish an approximate model, and obtaining the optimal solution for parameter optimization in the design space; Step 4: input the optimal solution of parameter optimization searched in the design space into the fluid-solid coupling friction dynamics model and the belt displacement torque model respectively to obtain the optimal result of friction pair parameter optimization of the no-load wet clutch in a wide speed range under low-speed and high-speed conditions.

2. The method for optimizing the torque suppression of a wet clutch with no-load in a wide speed range according to claim 1, characterized in that: Obtaining the initial curved groove profile line includes: Obtaining a plurality of first discrete points, and obtaining a cubic spline interpolation polynomial according to the plurality of first discrete points; Natural boundary conditions are set, the second-order derivative matrix of the interpolation function in the cubic spline interpolation polynomial is calculated, the coefficients of each term of the cubic spline interpolation polynomial are determined, and the initial curved groove shape line is obtained.

3. The method for optimizing the torque suppression of a wet clutch with no-load in a wide speed range according to claim 1, characterized in that: Constructing a new curved groove profile based on the initial curved groove profile includes: Taking the initial curved groove shape line as the initial shape line, selecting a number of second discrete points equidistantly radially on the initial shape line; The circumferential coordinates of the second discrete points are adjusted in angle to obtain new discrete points, and an optimal shape line is further generated. According to the optimal shape line, a new groove form is obtained, that is, the optimization problem of the initial curved groove shape line is converted into a numerical optimization problem of the parameters of the initial groove and the axial angle offset matrix.

4. The method for optimizing the torque suppression of a wet clutch with no-load in a wide speed range according to claim 1, characterized in that: The optimization objectives for designing the wide speed range no-load wet clutch with displacement torque include: The viscous shear peak displacement torque of the wide-speed range no-load wet clutch under low-speed conditions and the total displacement torque at the highest operating speed are taken as optimization targets.

5. The method for optimizing the torque suppression of a wet clutch with no-load in a wide speed range according to claim 4, characterized in that: The constraints corresponding to the optimization objectives are established as follows: The viscous shear peak displacement torque under the low speed condition and the minimum total displacement torque under the highest operating speed are set as optimization objectives: minf(X)=(T s ,T) Among them, minf(X) is the optimization target, T s is the displacement torque of the wet clutch at low speed, and T is the displacement torque of the wet clutch at high speed.

6. The method for optimizing the torque suppression of a no-load wet clutch with a wide speed range according to claim 5, characterized in that: The method for obtaining the displacement torque of the wet clutch at low speed is: Among them, T si is the average value of the sum of displacement moments of the viscous shear bands of each friction pair, and t is the simulation time; The method for obtaining the average value of the sum of the displacement moments of the viscous shear bands of the friction pairs is: Among them, r e is the full film lubrication equivalent radius, r i is the inner radius of the single-plate wet clutch, r o is the outer radius of the single-plate wet clutch, τ θ is the internal friction force per unit area of ​​the oil film zone, θ is the angle relative to the central axis of the clutch, is the internal friction force per unit area outside the oil film area.

7. The method for optimizing the torque suppression of a wet clutch with no-load in a wide speed range according to claim 5, characterized in that: The belt displacement torque of the wet clutch at high speed includes: the viscous shear belt displacement torque of the lubricating oil and the friction belt displacement torque; The method for obtaining the friction belt displacement torque is: Where e is the coefficient of restitution, is the Hertz contact stiffness coefficient, λ is the plastic stiffness coefficient, δ, are the relative speed and relative displacement of the steel plate and the friction plate, is the residual plastic deformation, δ m is the maximum relative displacement, f i is the collision friction, r o is the outer radius of the single-plate clutch, w is the speed difference between the steel plate and the friction plate, w r is the critical speed of clutch collision, v is the Poisson's ratio of the material, k is the material stiffness coefficient, R1 is the steel plate contact radius, R2 is the friction plate contact radius, k1 is the steel plate stiffness coefficient, and k2 is the friction plate stiffness coefficient.

8. The method for optimizing the torque suppression of a wet clutch with no-load in a wide speed range according to claim 1, characterized in that: Obtaining the optimal solution for searching parameter optimization in the design space includes: Obtaining the optimal solution for parameter optimization in the design space is divided into two stages: With (N g ,h g , δ c ,δ r ) This set of friction plate oil groove structural parameters is used as the design variables in the first stage, where N g is the number of oil tanks, h g is the oil groove depth, δ c =θ g / θ p The circumferential groove-to-platform ratio, δ, characterizes the groove width r =(r g -r i ) / (r o -r i ) characterizes the radial groove-dam ratio which is the ratio of the inner and outer radius of the groove area to the inner and outer radius of the friction plate, assigns values ​​to the design variables of the first stage, generates the design space of the first stage for several groups of test sample points, adopts the elliptic basis neural network model combined with the constraint conditions, establishes the approximate model of the first stage, and obtains the optimal solution for searching the optimization parameters in the design space of the first stage; The optimal solution of parameter optimization search in the design space of the first stage is combined with the circumferential offset angle of discrete points on the groove shape line as the design variables of the second stage. The elliptical basis neural network model is combined with the constraints to establish an approximate model of the second stage to obtain the optimal solution of parameter optimization search in the design space of the second stage.

9. The method for optimizing the torque suppression of a wet clutch with no-load in a wide speed range according to claim 1, characterized in that: Obtaining the optimal results of the friction pair parameter optimization of the no-load wet clutch in a wide speed range under low speed and high speed conditions includes: The optimal solution of parameter optimization searched in the design space is input into the fluid-solid coupling friction dynamics model and the belt displacement torque model respectively, so as to obtain the optimization results to be verified for the friction pair parameter optimization of the no-load wet clutch in a wide speed range under low-speed and high-speed conditions; Substituting the random solutions of the design variables into the input fluid-solid coupling friction dynamics model and the belt displacement torque model to obtain random optimization results; The random optimization result is compared with the optimization result to be verified. If the random optimization result is the optimal result, steps S3-S4 are repeated to establish the approximate model until the optimization result to be verified is the optimal result. If the optimization result to be verified is the optimal result, the optimization result to be verified is output, that is, the optimal result of the optimization of the friction pair parameters of the wide speed range no-load wet clutch under low-speed and high-speed conditions is obtained.

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