Tire performance prediction simulation method and apparatus

Abstract

To easily predict the tire performance for a plurality of different materials.SOLUTION: A tire performance prediction simulation method that obtains the rolling friction energy of a tire for each material includes a friction energy acquisition step S1 of acquiring the friction energy of each of a plurality of materials. The method also includes: a material-specific coefficient calculation step S2 of calculating a material-specific coefficient being a value of a ratio of friction energy of one reference material in the plurality of materials to friction energy of each of other materials; and a rolling analysis step S3 of performing rolling analysis of a tire using the reference material and calculating the rolling friction energy of the tire using the reference material. Furthermore, the method includes a rolling friction energy calculation step S4 of calculating the rolling friction energy of the tire using the other materials on the basis of the rolling friction energy of the tire using the reference material and the material-specific coefficients.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for predicting tire performance simulation, and particularly to a method and apparatus for predicting tire performance by material and simulating the same.

Background Art

[0002] Generally, tires are worn due to friction with the road surface when the vehicle is running. Therefore, in the development of tires, a method of predicting and evaluating the tire wear amount using numerical analysis such as the finite element method may be used without actually manufacturing the tires and mounting them on the vehicle for testing.

[0003] Prior Patent Document 1 discloses a method of predicting the change over time of a tire by inputting material conditions and the like before FEM analysis and performing FEM analysis.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When predicting the tire performance by material, it may be necessary to change only the material under the same analysis conditions and perform a simulation. In that case, since a plurality of models are created and material settings are made for each of the plurality of models, there is a problem that man-hours and analysis time are significantly increased. Note that the problem cannot be solved even by the tire change-over-time prediction method disclosed in the prior document 1.

Means for Solving the Problems

[0006] The tire performance prediction simulation method according to the present disclosure is a tire performance prediction simulation method for obtaining the rolling friction energy for each material of a tire, and includes a friction energy acquisition step of obtaining the friction energy of each of a plurality of materials. Further, it includes a material-specific coefficient calculation step of calculating a material-specific coefficient which is a value of the ratio of the friction energy of one reference material among the plurality of materials to the friction energy of each of the other materials, and a rolling analysis step of performing a rolling analysis of a tire using the reference material and calculating the rolling friction energy of the tire using the reference material. Furthermore, it includes a rolling friction energy calculation step of calculating the rolling friction energy of a tire using the other materials based on the rolling friction energy of the tire using the reference material and the material-specific coefficient.

Advantages of the Invention

[0007] According to the tire performance prediction simulation method and apparatus according to the present disclosure, the tire performance for each material can be easily predicted.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings, an example of an embodiment of a tire performance prediction simulation method and apparatus according to the present disclosure will be described in detail. The embodiments described below are merely examples, and the present invention is not limited to the following embodiments. Further, forms obtained by selectively combining a plurality of the following embodiments and modification examples are included in the present invention.

[0010] Using FIG. 1, a prediction simulation method for the frictional energy of a tire, which is an example of an embodiment, will be described in detail. FIG. 1 is a flowchart showing the prediction simulation method for the frictional energy of a tire. According to the flowchart of FIG. 1, each step will be described in detail. Further, in the description of each step, reference may be made to FIGS. 2 to 5.

[0011] Step S1 is to obtain the frictional energy of a plurality of materials. Here, the plurality of materials are a plurality of materials used for the tread portion of the tire. The main material of the tread portion is, for example, a crosslinked rubber composition. The tread portion is the outermost periphery in the tire radial direction and is the portion where the tire contacts the road surface. Here, the frictional energy of each of the plurality of materials is obtained as a measured value by a test or a calculated value by analysis. At this time, it is preferable that the acquisition conditions for the frictional energy of the plurality of materials are the same. That is, the conditions when conducting the test and the analysis conditions when conducting the analysis are preferably the same for all of the plurality of materials. Further, the acquisition of the measured value by the test and the calculated value by the analysis may be performed by a known method. For example, it is a test using a tester capable of measuring the slip amount and the shear force. Further, a similar test may be performed in simulation. In these cases, the frictional energy is obtained based on the slip amount and the shear force.

[0012] In step S2, a coefficient for each material is calculated based on the frictional energies of the plurality of materials obtained above. Specifically, the coefficient for each material is calculated based on the relationship between the frictional energy of one reference material among the plurality of materials and the frictional energies of the other materials. The coefficient for each material is represented by the value of the ratio of the frictional energy of the other materials to the frictional energy of the reference material. Although it will be described in detail later, the calculated coefficient for each material is stored by the memory 12 of the simulation device 1. Hereinafter, when describing materials other than the reference material among the plurality of materials, they may be referred to as other materials.

[0013] Step S2 sets a reference material as a reference among the plurality of materials. When setting the reference material, among the plurality of materials, a material with a predetermined material property near the median value may be used as the reference material. The predetermined material property is, for example, one of Young's modulus, breaking strength, breaking strain, hardness, etc. Young's modulus, breaking strength, breaking strain, etc. may be obtained by known methods. For example, Young's modulus, breaking strength, and breaking strain are obtained by a tensile test or the like. Also, hardness is obtained by a durometer hardness test or the like. The reference material is, for example, a rubber material including natural rubber, butadiene rubber, carbon black, silica, oil, etc.

[0014] Specifically, the coefficient for each material may be represented by the value of the ratio of the frictional energy of the other materials to the frictional energy of the reference material, as shown in FIG. 2. FIG. 2 is a diagram illustrating the value of the ratio (coefficient for each material) of the frictional energy of the other materials to the frictional energy of the reference material. In FIG. 2, registration number #001 indicates the reference material, and the other numbers indicate the other materials. The coefficient for each material is the number obtained by dividing the frictional energy of the other materials by the frictional energy of the reference material.

[0015] Further, the coefficient for each material may be shown in association with the relationship between the material properties of the reference material and other materials as shown in FIG. 3. FIG. 3 is a graph illustrating the relationship between the value of the ratio of frictional energy (coefficient for each material) and the value of the ratio of material properties in the reference material and other materials. The vertical axis of FIG. 3 represents the coefficient for each material, and the horizontal axis represents the value of the ratio of a predetermined material property. Also, the material property in FIG. 3 is the wear amount of the material. The wear amount of the material will be described later. FIG. 4 shows a diagram exemplifying the numerical values of each point of the graph of FIG. 3.

[0016] In FIG. 3, the white dot where the coefficient for each material and the value of the ratio of material properties are 1 is the point indicating the reference material. The black dots are the points indicating other materials. For example, as shown in FIGS. 3 and 4, point a1 is a material whose material property is 1.2 times that of the reference material and whose value of the ratio of frictional energy is 1.24 times. Thus, the coefficient for each material can be obtained from the value of the ratio of a predetermined material property to the reference material. As described above, among the plurality of materials, a material whose predetermined material property is near the median value may be used as the reference material. Here, the value of the ratio of the material property on the horizontal axis of FIG. 3 may be the value of the ratio of the above-described predetermined material property. That is, the value of the ratio of the material property on the horizontal axis of FIG. 3 may be the value of the ratio such as Young's modulus, breaking strength, breaking strain, and hardness. Also, the material property on the horizontal axis of FIG. 3 may be the value of the ratio of the parameter related to the wear of the material. The parameter related to the wear of the material is, for example, the wear amount of the material. Also, the wear amount of the material, etc. may be obtained by a known method. For example, it is obtained by a Lambourn test.

[0017] Step S3 performs a rolling analysis on the tire using the above reference material. Also, by performing the rolling analysis, the rolling frictional energy of the tire using the reference material is calculated.

[0018] Using FIG. 5, the calculation of the rolling frictional energy by the rolling analysis according to the present embodiment will be described in detail. FIG. 5 is a flowchart for explaining the rolling analysis according to the present embodiment. Each step will be described in detail according to the flowchart of FIG. 5.

[0019] In step S11, data on the design conditions for the tire including the cross-sectional shape of the pneumatic tire to be analyzed is input. Specifically, various dimensional specifications such as the outer shape and internal structure of the tire, and the shape, arrangement, material physical property values, etc. of each tire member such as the tread rubber constituting the tire are input. Here, as the material physical property values of the tread rubber, the material physical property values of the reference material set above are input. Although details will be described later, the input of these pieces of information is performed by the input unit 13 of the simulation device 1. It may also be performed through a recording medium, a network, or the like.

[0020] In step S12, based on the data input in step S1, a tire model is created in which the tire to be simulated is divided into a finite number of elements. The tire model is a numerical conversion of the input data format for a computer program created based on numerical and analytical methods for the tire. In the present embodiment, the finite element method (FEM) is used as the numerical analysis method. Therefore, the tire model is divided into a plurality of elements by element division corresponding to the finite element method, for example, mesh division.

[0021] In step S13, the rolling conditions necessary when rolling the tire model obtained above are set. Examples of the rolling conditions include, as conditions on the tire side, for example, rim size, air pressure, etc., and as conditions on the road surface side, for example, friction coefficient, etc. In the present embodiment, as the rolling conditions, the load applied to the axle, longitudinal force, lateral force, camber angle, etc. are set in the steady state, driving state, turning state, and braking state.

[0022] In step S14, a rolling analysis of the tire model is performed under the above rolling conditions. The rolling analysis analyzes the changes when the tire in contact with the road surface rotates, that is, the deformation of the tire shape, and is itself known, and can be performed using such known methods.

[0023] In this embodiment, after mounting the above tire model on the rim model and applying a predetermined air pressure, the tire model is brought into contact with the road surface model and rolled under the above rolling conditions for analysis. Then, time-series data of the pressure and displacement of the nodes (surface nodes) located on the tread surface are obtained for all the surface nodes. The rolling analysis is performed for all the rolling conditions set above.

[0024] In step S15, from the results of the rolling analysis in step S14, the reference friction energy is calculated for each of the rolling conditions. The reference friction energy serves as a reference for calculating the wear amount based on the energy due to friction when the tire contacts the road surface. The reference friction energy (E) received from the road surface while an arbitrary surface node on the tread surface is in contact with the road surface (i.e., during indentation to kick-out) is represented by the following formula (1).

Equation

[0025] Here, L represents the contact length (the length from contact to separation), Px represents the circumferential shear pressure, Py represents the width-direction shear pressure, Sx represents the circumferential slip displacement, and Sy represents the width-direction slip displacement.

[0026] When the reference friction energy has been calculated for all the set rolling conditions (YES in step S16), the mode friction energy is calculated in step S17. On the other hand, when the reference friction energy has not been calculated for all the rolling conditions (NO in step S16), the rolling analysis is performed until the reference friction energy is calculated for all the rolling conditions.

[0027] Step S17 calculates the mode frictional energy for each mode of tire running in which the simulation is performed, based on the reference frictional energy calculated in step S15. As an example, the mode frictional energy in each mode is calculated by adding the increase in the reference frictional energy due to the longitudinal force, lateral force, and camber angle to the reference frictional energy during straight running (see, for example, Japanese Patent Application Laid-Open No. 2015-123941). Since it is known to calculate the mode frictional energy from the reference frictional energy, the description thereof is omitted.

[0028] Each running mode of the tire refers to each running state in which the vehicle goes straight, turns, drives, or brakes according to the longitudinal G and lateral G. The forces generated on the axle in each mode are defined as the longitudinal force (Fx), the lateral force (Fy), and the load (Fz). Straight running is a state of 0G (Fx: 0, Fy: 0, Fz: arbitrary load). Turning is a state in which an arbitrary G is applied to the left and right (Fx: 0, Fy: ± arbitrary load, Fz: arbitrary load). The right turn and the left turn are determined by the sign of the arbitrary load applied to Fy. Driving is a state in which an arbitrary G is applied forward (Fx: arbitrary load, Fy: 0, Fz: arbitrary load). Braking is a state in which an arbitrary G is applied backward (Fx: -arbitrary load, Fy: 0, Fz: arbitrary load). Here, the arbitrary G is set, for example, in increments of 0.05G. Note that G is the acceleration due to gravity.

[0029] Step S18 calculates the rolling frictional energy of the tire using the reference material by multiplying the mode frictional energy of each mode obtained above by the running frequency of each mode and integrating them. That is, for the mode frictional energy of each mode, the running frequency of that mode is multiplied, and the obtained products are added together to obtain the frictional energy at each surface node in the tire running for which the simulation is performed. Thereby, the rolling frictional energy of the tire using the reference material is obtained for all the surface nodes located on the tire surface. Note that the running frequency is the ratio of each mode when the tire is run on a wear test course or the like, and is obtained by actual measurement during actual vehicle running or analysis by vehicle simulation or the like.

[0030] Step S4 calculates the rolling friction energy of a tire using other materials based on the rolling friction energy of the tire using the reference material calculated in the above rolling analysis and the coefficient for each material. Specifically, the rolling friction energy of a tire using other materials can be obtained by multiplying the rolling friction energy of the tire using the reference material by the coefficient for each material in the other materials. As a result, it is possible to obtain the rolling friction energy of a tire using other materials without performing a rolling analysis on the tire using other materials. Also, as a result, in the comparison of the rolling friction energy for each material among a plurality of materials, it is not necessary to perform a plurality of rolling analyses, thus reducing the man-hours.

[0031] In step S5, the wear amount is calculated based on the rolling friction energy obtained in step S4. Generally, there is a correlation between friction energy and wear amount. That is, when the friction energy is large, the wear amount becomes large, and when the friction energy is small, the wear amount becomes small. Therefore, by clarifying the correlation between friction energy and wear amount in advance, it is possible to calculate the wear amount from the friction energy. As a result, it is possible to calculate the wear amount of a tire using other materials without performing a rolling analysis. Also, as a result, in the comparison of the wear amount for each material among a plurality of materials, it is not necessary to perform a plurality of rolling analyses, thus reducing the man-hours.

[0032] Using FIG. 6, the simulation device 1 for implementing a method for simulating tire wear amount, which is an example of an embodiment, will be described in detail.

[0033] FIG. 6 is a diagram showing a simulation device 1 which is an example of an embodiment of the present disclosure. The simulation device 1 is configured by a computer including a control device 10 including a processor 11 and a memory 12, and executes an analysis of the tire wear amount during vehicle travel. The simulation device 1 may be configured by one computer or may be configured by a plurality of computers. Also, a part of the functions of the simulation device 1 may exist in a server or the like connected via a communication network.

[0034] The simulation device 1 includes an input unit 13 and an output unit 14. The input unit 13 is an input interface for inputting information necessary for the execution of the simulation, and examples thereof include a keyboard and a mouse. The information input by the input unit 13 includes, for example, analysis conditions, creation conditions of a tire model, and the like. The output unit 14 is a liquid crystal, an organic EL display, or the like on which an input screen, an output screen such as a simulation result, and the like are displayed.

[0035] The simulation device 1 includes a frictional energy acquisition unit 15, a coefficient calculation unit 16 for each material, a rolling analysis unit 17, and a rolling frictional energy calculation unit 18 as means for performing the above simulation. Further, it may include a wear amount calculation unit 19 that calculates a tire wear amount based on the rolling frictional energy.

[0036] The simulation device 1 is configured to be able to calculate the rolling frictional energy of a tire using the finite element method (FEM). Further, it is configured to be able to calculate the rolling frictional energy of a tire using other materials for which rolling analysis has not been performed. The processor 11 realizes the functions of the frictional energy acquisition unit 15, the coefficient calculation unit 16 for each material, the rolling analysis unit 17, the rolling frictional energy calculation unit 18, and the wear amount calculation unit 19 by reading and executing a simulation program. The memory 12 is composed of, for example, a RAM, a ROM, a hard disk, etc., and stores a simulation program, various setting information necessary for the execution of the simulation including the above-described rolling conditions, simulation results, and calculation results including coefficients for each material.

[0037] As described above, according to the tire performance prediction simulation method and apparatus having the above configuration, among a plurality of materials, by performing a rolling analysis only on a tire using a reference material, it is possible to obtain the tire performance when the material of the tread portion is changed without performing a rolling analysis on a tire using other materials. Thereby, it is possible to easily predict the tire performance for each material among a plurality of different materials. In addition, since it becomes possible to easily predict the tire performance, it also becomes easy to compare the tire performance when the material of the tread portion is changed.

Explanation of Signs

[0038] 1 Simulation apparatus, 10 Control apparatus, 11 Processor, 12 Memory, 13 Input section, 14 Output section, 15 Frictional energy acquisition section, 16 Coefficient acquisition section for each material, 17 Rolling analysis section, 18 Rolling frictional energy calculation section, 19 Wear amount calculation section

Claims

1. A tire performance prediction simulation method for obtaining rolling friction energy for different tire materials, comprising: a friction energy acquisition step of acquiring the friction energy of each of a plurality of materials; a material-specific coefficient calculation step of calculating a material-specific coefficient that is the ratio of the friction energy of one reference material among the plurality of materials to the friction energy of each of the other materials; a rolling analysis step of performing a rolling analysis of a tire using the reference material and calculating the rolling friction energy of the tire using the reference material; a rolling friction energy calculation step of calculating the rolling friction energy of a tire using the other material based on the rolling friction energy of the tire using the reference material and the material-specific coefficient.

2. The tire performance prediction simulation method according to claim 1, wherein the rolling friction energy calculation step calculates the rolling friction energy of a tire using the other material by multiplying the rolling friction energy of the tire using the reference material by the material-specific coefficient of the other material.

3. The tire performance prediction simulation method according to claim 1, wherein the reference material is a material among the plurality of materials having a predetermined material property near the median value.

4. The tire performance prediction simulation method according to claim 3, wherein the material property is one of Young's modulus, breaking strength, breaking strain, a parameter related to wear, and hardness.

5. The tire performance prediction simulation method according to any one of claims 1 to 4, further comprising a wear amount calculation step of calculating the wear amount of the other material based on the relationship between the friction energy and the wear amount and the rolling friction energy of a tire using the other material.

6. A tire performance prediction simulation apparatus for obtaining rolling friction energy for different tire materials, comprising: friction energy acquisition means for acquiring the friction energy of each of a plurality of materials; material-specific coefficient calculation means for calculating a material-specific coefficient that is the ratio of the friction energy of one reference material among the plurality of materials to the friction energy of each of the other materials; rolling analysis means for performing a rolling analysis of a tire using the reference material and calculating the rolling friction energy of the tire using the reference material; A tire performance prediction simulation device including: a rolling friction energy calculation means for calculating the rolling friction energy of a tire using the other material based on the rolling friction energy of the tire using the reference material and the coefficient for each material.

Images