Simulation method, device, and program for tire cornering power

Abstract

To provide a simulation device, a method, and a program capable of predicting tire cornering power with high efficiency and high accuracy.SOLUTION: This simulation method for tire cornering power comprises steps of: measuring a real measurement value of the cornering power; performing FEM analysis for rolling a tire model of a tire in which a split number in a tire circumferential direction is defined as A under a condition that a permitted slip parameter is B, calculating a calculation value of the cornering power, and acquiring a relative value C of the calculation value when the real measurement value is 100; changing A with B constant to calculate a first approximation straight line indicating a relationship between A and C, changing B with A constant to calculate a second approximation straight line indicating a relationship between B and C, forming a virtual plane including the first and second approximation straight lines in a three-dimensional space with A, B, and C as axes; and extracting a range where C is near 100 as an optimal range on the virtual plane.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method, device, and program for simulating the cornering power of a tire, and more particularly to a simulation method, device, and program for efficiently predicting the cornering power of a tire. [Background technology]

[0002] Cornering power, which is an index of tire handling stability, can be calculated by FEM (Finite Element Method) analysis. However, the calculated values obtained by FEM analysis do not quantitatively match the measured values, and there are issues with accuracy. Patent Document 1 discloses a simulation device and the like that takes into account the temperature dependency of the friction coefficient in calculating cornering power, thereby improving prediction accuracy. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-96785 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, in FEM analysis, improving accuracy increases the calculation load, so existing technologies, including the technology disclosed in Patent Document 1, still have room for improvement in terms of achieving both efficiency and accuracy.

[0005] An object of the present invention is to provide a simulation device, method, and program that can predict tire cornering power with high efficiency and high accuracy. [Means for solving the problem]

[0006] The method for simulating the cornering power of a tire according to the present invention includes the steps of rolling the tire on a road surface and measuring the measured value of the cornering power, performing an FEM analysis in which a tire model of a tire having a circumferential division number of A is rolled under the condition that an allowable slip parameter is B, calculating the calculated value of the cornering power, and obtaining a relative value C of the calculated value when the measured value is set to 100, and setting B to a constant b1 and A to a m The first approximation line showing the relationship between A and C is calculated by changing the value of A at m levels (m is a natural number of 2 or more), and A is kept constant at a1, and B is changed from b1 to b n the first approximate line and the second approximate line in a three-dimensional space having A, B, and C as its axes; and extracting, on the virtual plane, a range in which C is approximately 100 as the optimum range.

[0007] The optimum range obtained by the above method may be such that C is 95 or more and 105 or less. Furthermore, in the optimum range obtained by the above method, A and B may satisfy the relationship y = {(-0.1012 × A + 103.91) + (-1049.9 × B + 119.99)} / 2, 95≦y≦100. Furthermore, in the optimum range obtained by the above method, A may be 60 or more and 120 or less. Furthermore, in the optimum range obtained by the above method, A may be 60 or more and 90 or less, and B may be 0.008 or more and 0.02 or less.

[0008] The tire cornering power simulation device according to the present invention includes an input unit for inputting an actual measurement value of cornering power measured by rolling a tire on a road surface, an analysis unit for performing an FEM analysis in which a tire model of a tire having a tire circumferential division number of A is rolled under a condition in which an allowable slip parameter is B, and for calculating a calculated value of cornering power, and an analysis unit for obtaining a relative value C of the calculated value when the actual measurement value is set to 100, setting B to a constant value b1, and setting A to a value between a1 and a m The first approximation line showing the relationship between A and C is calculated by changing the value of A at m levels (m is a natural number of 2 or more), and A is kept constant at a1, and B is changed from b1 to bn and an optimum range extraction unit that varies A at n levels (n is a natural number of 2 or more) to calculate a second approximate line that shows the relationship between B and C, forms a virtual plane that includes the first approximate line and the second approximate line in a three-dimensional space with A, B, and C as its axes, and extracts a range in the virtual plane where C is around 100 as an optimum range.

[0009] The optimal range obtained by the above device may be such that C is 95 or more and 105 or less. Furthermore, in the optimal range obtained by the above device, A and B may satisfy the relationship y = {(-0.1012 × A + 103.91) + (-1049.9 × B + 119.99)} / 2, 95≦y≦100. Furthermore, in the optimal range obtained by the above method, A may be 60 or more and 120 or less. Furthermore, in the optimal range obtained by the above method, A may be 60 or more and 90 or less, and B may be 0.008 or more and 0.02 or less.

[0010] A program according to the present invention is characterized in that it causes a computer to execute the above simulation method. [Effects of the Invention]

[0011] According to the method, device, and program for simulating the cornering power of a tire according to the present invention, it is possible to achieve both high efficiency and high accuracy in predicting cornering power. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a side view of a tire model according to an example embodiment. [Figure 2] FIG. 1 is a block diagram of a simulation device according to an embodiment. [Figure 3] FIG. 10 is a diagram for explaining a method for calculating an optimum range in an example of an embodiment. [Figure 4] 10 is a flowchart illustrating a method for calculating a relative value of cornering power in a simulation method according to an example of an embodiment. [Figure 5] 10 is a flowchart illustrating a method for calculating an optimum range in a simulation method according to an example of an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] An example of a detection method according to the present invention will be described in detail below with reference to the drawings. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment. Furthermore, the present invention includes configurations that selectively combine the components of multiple embodiments and variations described below.

[0014] 1 is a side view of a tire model 10 according to an embodiment. The tire model 10 is a 3D model of an actual tire, and is used to calculate tire behavior. In this specification, the tire model 10 is used when performing a finite element method (FEM) analysis, which will be described later.

[0015] In Fig. 1, the number of divisions A in the tire circumferential direction of the tire model 10 is 60. That is, the tire model 10 is divided into 60 meshes 12 of the same shape arranged in the tire circumferential direction. The number of divisions A can be changed, for example, within a range of 20 to 300. The tire is, for example, a pneumatic tire.

[0016] 2 is a block diagram of a simulation device 20 according to an example embodiment. The simulation device 20 is configured by an information processing device including, for example, a processor 21, a memory 22, etc. The processor 21 executes arithmetic processing for controlling the simulation device 20. The memory 22 stores a control program for controlling the processor 21, etc., and is configured by, for example, a RAM, a ROM, a hard disk, etc. The control program includes a program that causes the information processing device to execute a method for simulating tire cornering power (hereinafter, sometimes referred to as CP). The simulation device 20 may be configured by one information processing device or by multiple information processing devices.

[0017] The simulation device 20 includes an input unit 24, an analysis unit 26, and an optimum range extraction unit 28. The simulation device 20 is used to simulate the CP of a tire. By using the simulation device 20, the CP of a tire can be predicted with high efficiency and high accuracy.

[0018] The input unit 24 is used to input the actual CP value measured by rolling an actual tire on a road surface. The input unit 24 may include a known keyboard, mouse, or the like. The actual CP value is measured while the tire is rotating with the contact surface in contact with the road surface. At this time, a load is applied to the tire and it is pressed against the road surface. The road surface is, for example, a flat belt. The tire rotation speed can be controlled by changing the moving speed of the flat belt. The road surface is not limited to a flat surface and may be the curved surface of a drum. The tire lateral force is measured when the tire is oriented in the same direction as the rotation direction of the road surface (0° case) and when the tire is tilted 1° relative to the rotation direction of the road surface (1° case), and the difference in the tire lateral force between the 1° case and the 0° case is taken as the actual CP value. The measurement is performed, for example, on a smooth road surface with a mean profile depth (MPD), a roughness index, of less than 0.3. The material of the road surface is, for example, steel. The input unit 24 may also be used to input data used in calculations in the analysis unit 26, such as a tire model 10, an allowable slip parameter B, a tire rotational angular velocity ω, and a tire radius R, as will be described later.

[0019] The analysis unit 26 performs an FEM analysis in which the tire model 10 rolls under the condition that the allowable slip parameter is B, and calculates the calculated value of CP. Here, the allowable slip parameter B is a constant for determining that the tire model 10 and the contact patch are slipping without sticking in order to converge the calculations in the FEM analysis. In an actual tire, when the relative speed between the tire and the road surface at the contact patch is slow, the shear force acting on the tire is small, and the tire does not slip relative to the road surface. However, if the FEM analysis assumes that the tire model 10 and the contact patch are stuck, the calculations do not converge or take a long time to converge. Therefore, for convenience, the allowable slip parameter B is used to assume that the tire is slipping without sticking. This makes it possible to improve calculation efficiency while maintaining prediction accuracy.

[0020] The allowable slip parameter B, tire rotational angular velocity ω, tire radius R, and allowable slip velocity v satisfy the relationship v=B×2×ω×R.

[0021] The optimum range extraction unit 28 calculates an optimum range 30 suitable for FEM analysis from the number of divisions A of the tire model 10, the allowable slip parameter B, the calculated value of CP, and the measured value of CP. That is, the optimum range extraction unit 28 causes the analysis unit 26 to perform FEM analysis on the number of divisions A and the allowable slip parameter B of the selected tire model 10 to obtain the calculated value of CP, while accepting the measured value under the same conditions from the input unit 24, and calculates the optimum range 30. A specific method for calculating the optimum range 30 will be described below with reference to FIG. 3.

[0022] <Calculation method for optimal range 30> (1) The measured value of CP is set to 100, and the calculated value of CP is expressed as a relative value C. A three-dimensional space is created with the number of divisions A, the allowable slip parameter B, and the relative value C as axes. (2) The allowable slip parameter B is fixed at b1, and the number of divisions A is a1 to a m The number of divisions A is changed at m levels (m is a natural number of 2 or more) and an FEM analysis is performed to calculate a first approximate straight line L1 that indicates the relationship between the number of divisions A and the relative value C. (3) The number of divisions A is fixed at a1, and the allowable slip parameter B is set to b1 to b n The FEM analysis is performed by changing the allowable slip parameter B at n levels (n is a natural number of 2 or more), and a second approximate straight line L2 showing the relationship between the allowable slip parameter B and the relative value C is calculated. (4) In a three-dimensional space with axes of the division number A, the allowable slip parameter B, and the relative value C, a virtual plane 32 including the first approximate straight line L1 and the second approximate straight line L2 is formed, and the range in the virtual plane 32 where the relative value C is close to 100 is extracted as the optimal range 30.

[0023] By performing FEM analysis in the optimum range 30 calculated using the above-described simulation device 20, it is possible to obtain a calculated value for CP that is close to the actually measured value, thereby improving the accuracy of the simulation. Furthermore, by reducing the number of divisions A, the calculation load in the FEM analysis can be reduced, so by selecting a small number of divisions A in the obtained optimum range 30 and performing the FEM analysis, it is possible to improve the efficiency of the simulation.

[0024] The optimum range 30 is, for example, a range in which the relative value C is 95 or more and 105 or less.

[0025] In the optimum range 30, A, B, and C satisfy the relationship C = {(-0.1012 x A + 103.91) + (-1049.9 x B + 119.99)} / 2, 95 ≦ C ≦ 105, for example. In this case, the range enclosed by the bold line in Table 1 is the optimum range 30. The above relationship can be obtained by varying A at three levels: 60, 90, and 120, and B at three levels: 0.01, 0.02, and 0.05.

[0026] [Table 1]

[0027] From the viewpoint of efficiency of the simulation, A is preferably 60 or more and 120 or less, and more preferably A is 60 or more and 90 or less, and B is 0.008 or more and 0.024 or less.

[0028] Next, a simulation method for calculating CP will be described with reference to Figures 4 and 5. Figure 4 is a flowchart showing a method for calculating a relative value C of CP in the simulation method according to an example of an embodiment, and Figure 5 is a flowchart showing a method for calculating an optimum range 30 in the simulation method according to an example of an embodiment.

[0029] In the flowchart shown in Fig. 4, an actual tire is rolled on a road surface, and the actual CP value is measured (S11). In addition, an FEM analysis is performed in which a tire model (the number of divisions in the tire circumferential direction is A) created based on the actual tire is rolled under the condition that the allowable slip parameter is B, and a calculated CP value is calculated (S12). Next, the actual CP value obtained in S11 is set as the reference (100), and the calculated CP value obtained in S12 is expressed as a relative value C (S13), and this flowchart ends.

[0030] In the flowchart shown in FIG. 5, first, a first approximate line L1 showing the relationship between the division number A and the relative value C, and a second approximate line L2 showing the relationship between the allowable slip parameter B and the relative value C are calculated (S21). The first approximate line L1 shows the relationship between the division number A and the relative value C, and the allowable slip parameter B is fixed at b1, and the division number A is changed from a1 to a m The second approximation line L2 shows the relationship between the allowable slip parameter B and the relative value C, and the division number A is fixed at a1, and the allowable slip parameter B is changed from b1 to b n The first approximate line and the second approximate line are calculated by changing the value of the linear function by n levels (n is a natural number of 2 or more). When calculating the first approximate line and the second approximate line, the method shown in the flowchart of FIG. 4 is used.

[0031] Next, a virtual plane 32 including the first approximate line L1 and the second approximate line L2 is formed in a three-dimensional space whose axes are the division number A, the allowable slip parameter B, and the relative value C (S22). Furthermore, on the virtual plane 32, a range where the relative value C is close to 100 is extracted as the optimum range 30, and this flowchart ends.

[0032] By performing FEM analysis in the optimal range 30 calculated using the above simulation method, it is possible to obtain calculated values for CP that are close to the measured values, thereby improving the accuracy of the simulation. Furthermore, by reducing the number of divisions A, the calculation load in the FEM analysis can be reduced, so by selecting a small number of divisions A in the obtained optimal range 30 and performing the FEM analysis, the efficiency of the simulation can be improved.

[0033] As described above, by using the simulation method, device, or program according to the present invention, the cornering power of a tire can be predicted with high efficiency and high accuracy. [Explanation of symbols]

[0034] 10 tire model, 20 simulation device, 21 processor, 22 memory, 24 input unit, 26 analysis unit, 28 optimum range extraction unit, 30 optimum range, 32 virtual plane, L1 first approximation line, L2 second approximation curve

Claims

1. a step of rolling the tire on a road surface and measuring an actual value of cornering power; performing an FEM analysis of a tire model of the tire, in which the number of divisions in the tire circumferential direction is set to A, in which the tire model is rotated under a condition in which the allowable slip parameter is set to B, to calculate a cornering power, and to obtain a relative value C of the calculated value when the actual measured value is set to 100; The B is changed to b １ and set A to a １ ~a ｍ and calculating a first approximate straight line showing the relationship between A and C, The A is a １ and set B to b １ ~b ｎ is changed at n levels (n is a natural number of 2 or more) and a second approximate straight line showing the relationship between B and C is calculated; forming a virtual plane including the first approximate straight line and the second approximate straight line in a three-dimensional space having axes A, B, and C, and extracting, on the virtual plane, a range in which C is close to 100 as an optimum range.

2. The simulation method according to claim 1 , wherein the optimum range is a range of C from 95 to 105.

3. 2. The simulation method according to claim 1, wherein, in the optimum range, A, B, and C satisfy a relationship of C={(-0.1012×A+103.91)+(-1049.9×B+119.99)} / 2, 95≦C≦105.

4. The simulation method according to claim 1 , wherein A is equal to or greater than 60 and equal to or less than 120 in the optimum range.

5. 2. The simulation method according to claim 1, wherein, in the optimum range, A is equal to or greater than 60 and equal to or less than 90, and B is equal to or greater than 0.008 and equal to or less than 0.

024.

6. an input unit for inputting an actual cornering power value measured by rolling the tire on a road surface; an analysis unit that performs an FEM analysis in which a tire model of the tire, in which the number of divisions in the tire circumferential direction is A, is rotated under a condition in which an allowable slip parameter is B, and calculates a calculated value of cornering power; A relative value C of the calculated value when the actual measured value is set to 100 is obtained, The B is changed to b １ and set A to a １ ~a ｍ and calculating a first approximate straight line showing the relationship between A and C, The A is a １ and set B to b １ ~b ｎ is changed at n levels (n is a natural number of 2 or more) and a second approximate straight line showing the relationship between B and C is calculated; an optimum range extraction unit that forms a virtual plane including the first approximate straight line and the second approximate straight line in a three-dimensional space having axes A, B, and C, and extracts a range in which C is close to 100 on the virtual plane as an optimum range.

7. 7. The simulation device according to claim 6, wherein the optimum range is a range in which C is 95 or more and 105 or less.

8. 7. The simulation device according to claim 6, wherein, in the optimum range, A, B, and C satisfy a relationship of C={(-0.1012×A+103.91)+(-1049.9×B+119.99)} / 2, 95≦y≦105.

9. 7. The simulation device according to claim 6, wherein A is equal to or greater than 60 and equal to or less than 120 in the optimum range.

10. 7. The simulation device according to claim 6, wherein, in the optimum range, A is equal to or greater than 60 and equal to or less than 90, and B is equal to or greater than 0.008 and equal to or less than 0.

024.

11. A program that causes a computer to execute the simulation method according to any one of claims 1 to 5.

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