JP2021195007A - Tire simulation method - Google Patents

Abstract

To provide a tire simulation method capable of calculating a rolling state of a tire model after removing residual lateral force.SOLUTION: A tire simulation method includes a rolling step of bringing, by a computer, a tire model 21 into contact with a road surface model 25, and calculating a rolling state of rolling the tire model relatively on the road surface model 25. The rolling step includes a first rolling step of calculating the rolling state of the tire model 21, allowing a degree of freedom of the road surface model 25 in a lateral direction intersecting a straight proceeding direction of the tire model 21.SELECTED DRAWING: Figure 4

Description

The present invention relates to a tire simulation method.

The following Patent Document 1 describes a method of creating a wear tire model. This creation method includes a procedure for rolling analysis of the initial tire model based on typical usage conditions, and a procedure for predicting the frictional energy per unit area in the tread contact area of the initial tire model by rolling analysis. Is included.

Japanese Patent No. 4569141

Generally, even if the slip angle and camber angle of a tire are zero, a minute lateral force (hereinafter referred to as "residual lateral force") is generated between the tire and the road surface due to the influence of belt ply, structural asymmetry, and the like. is doing. Even in recent tire models, since the internal structure such as the belt ply and the tread pattern are accurately reproduced, the above-mentioned residual lateral force is often generated when the rolling calculation is performed.

On the other hand, when analyzing the rolling state of an ideal tire model, tire wear, etc., there is a demand to calculate the rolling state of the tire model by removing the influence of the residual lateral force as described above.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a tire simulation method capable of calculating the rolling state of a tire model by removing the residual lateral force. ..

The present invention is a tire simulation method, wherein a tire model modeling the tire is input to a computer, and a road surface model modeling a road surface on which the tire rolls is input to the computer. The computer includes a rolling step of bringing the tire model into contact with the road surface model and calculating a rolling state in which the tire model rolls relatively on the road surface model, and the rolling step includes the tire model. It is characterized by including a first rolling step of calculating the rolling state of the tire model, allowing the degree of freedom of the road surface model in the lateral direction intersecting the straight direction of the tire model.

In the tire simulation method according to the present invention, in the rolling step, prior to the first rolling step, the degree of freedom of the road surface model is constrained and the rolling state of the tire model is calculated. It may include a rolling step.

In the tire simulation method according to the present invention, the second rolling step may be performed in a state where a slip angle is given to the tire model so that the residual lateral force of the tire model becomes zero or small. ..

In the tire simulation method according to the present invention, the first rolling step may be performed on a tire model after wear in which the tread portion of the tire model is worn.

By adopting the above configuration, the tire simulation method of the present invention can relatively move the road surface model in the lateral direction according to the residual lateral force generated in the tire model in the rolling state. Therefore, the tire simulation method of the present invention can calculate the rolling state of the tire model by removing the residual lateral force.

It is a perspective view which shows an example of the computer for executing the tire simulation method. It is sectional drawing which shows an example of the tire to be analyzed. It is a flowchart which shows an example of the processing procedure of the tire simulation method. It is a perspective view which shows an example of a tire model and a road surface model. It is sectional drawing which shows an example of a tire model. It is a flowchart which shows an example of the processing procedure of a rolling process. It is a flowchart which shows an example of the processing procedure of the rolling process of another embodiment of this invention. It is a top view which shows an example of the tire model which gave the slip angle. It is a graph which shows the left-right difference of the wear energy of the tire model after the wear progress. It is a graph which shows the average wear energy of each rib of a tread part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the tire simulation method of the present embodiment (hereinafter, may be simply referred to as "simulation method"), the rolling state of the tire model is calculated. It does not matter whether the tire to be analyzed actually exists or not. A computer is used for the simulation method of this embodiment. FIG. 1 is a perspective view showing an example of a computer 1 for executing a simulation method.

The computer 1 includes, for example, a main body 1a, a keyboard 1b, a mouse 1c, and a display device 1d. The main body 1a is provided with, for example, an arithmetic processing unit (CPU), a ROM, a working memory, a storage device such as a magnetic disk, and disk drive devices 1a1 and 1a2. Software or the like for executing the simulation method of the present embodiment is stored in the storage device in advance. Therefore, the computer 1 is configured as a simulation device for calculating the rolling state of the tire.

FIG. 2 is a cross-sectional view showing an example of the tire 11 to be analyzed. In the present embodiment, pneumatic tires for passenger cars are exemplified, but tires for heavy loads such as trucks and buses, and tires of other categories such as airless tires may be used.

The tire 11 of the present embodiment includes a carcass 16 extending from the tread portion 12 through the sidewall portion 13 to the bead core 15 of the bead portion 14, and a belt arranged outside the carcass 16 in the radial direction of the tire and inside the tread portion 12. A layer 17 is provided. A tread pattern is provided on the outer surface 12s of the tread portion 12 of the present embodiment.

The carcass 16 is composed of at least one carcass ply 16A, or one carcass ply 16A in the present embodiment. The carcass ply 16A has a carcass code (not shown) arranged at an angle of, for example, 75 to 90 degrees with respect to the tire equator C.

The belt layer 17 includes two outer belt plies 17A and 17B in which belt cords (not shown) are arranged at an angle of, for example, 10 to 35 degrees with respect to the tire circumferential direction. These belt plies 17A and 17B are overlapped with each other in a direction in which the belt cords intersect with each other.

FIG. 3 is a flowchart showing an example of the processing procedure of the tire simulation method. In the simulation method of the present embodiment, first, a tire model modeling the tire 11 is input to the computer 1 (step S1). FIG. 4 is a perspective view showing an example of the tire model 21 and the road surface model 25. FIG. 5 is a cross-sectional view showing an example of the tire model 21. The tire model 21 of FIG. 4 is shown in a simplified manner, and the tread pattern, the element F (i), and the like are omitted.

As shown in FIG. 5, in step S1 of the present embodiment, based on the information regarding the tire 11 shown in FIG. 2, the tire 11 can handle a finite number of elements F (i) (i) by a numerical analysis method. = 1, 2, ...) Is used to discretize. As a result, the tire model 21 is set in step S1. As the numerical analysis method, for example, a finite element method, a finite volume method, a difference method or a boundary element method can be appropriately adopted, but in the present embodiment, the finite element method is adopted.

As shown in FIG. 5, for the element F (i), for example, a tetrahedral solid element, a pentahedral solid element, a hexahedral solid element, or the like is used. Each element F (i) has a plurality of nodes 31. Further, each element F (i) is provided with a linear side 32 connecting the nodes 31 and 31. Numerical data such as an element number, a node number 31, and a coordinate value of the node 31 are defined in each of such elements F (i). Further, each element F (i) has material properties (for example, density, Young's modulus, damping coefficient, loss tangent (tanδ)), and / or complex elastic modulus of the tire member (tread rubber 12G, etc.) shown in FIG. Numerical data such as E *) is defined.

The tire model 21 has a carcass ply model 40 that models the carcass ply 16A (shown in FIG. 2) and a belt ply model 41A that models the belt plies 17A and 17B (shown in FIG. 2) as its internal structure. 41B is set.

A rubber model 21G that models a rubber member 11G (shown in FIG. 2) is set in the tire model 21. The rubber model 21G includes a tread rubber model 22G that models the tread rubber 12G (shown in FIG. 2) and a sidewall rubber model 23G that models the sidewall rubber 13G (shown in FIG. 2). The tread pattern of the tire 11 shown in FIG. 2 is reproduced on the outer surface 21s of the tread portion 21a (tread rubber model 22G). The tire model 21 is input to the computer 1 shown in FIG.

Next, in the simulation method of the present embodiment, the road surface model 25 (shown in FIG. 4) that models the road surface (not shown) on which the tire 11 rolls shown in FIG. 2 is input to the computer 1 (step S2). ). As shown in FIG. 4, in step S2, the road surface has a finite number of elements G (i) (i =) that can be handled by the numerical analysis method (finite element method in this embodiment) based on the information about the road surface. It is discretized using 1, 2, ...). As a result, the road surface model 25 is set in step S2.

The element G (i) is composed of a rigid plane element set to be non-deformable. The element G (i) is provided with a plurality of nodes 38. Further, in the element G (i), numerical data such as an element number and a coordinate value of a node 38 is defined.

In the present embodiment, a road surface model 25 having a smooth surface is exemplified, but if necessary, a fruit such as a fine unevenness such as an asphalt road surface, an irregular step, a dent, a swell, or a rut. Unevenness or the like that is close to the traveling road surface may be provided. The road surface model 25 is input to the computer 1 shown in FIG.

Next, in the simulation method of the present embodiment, the computer 1 brings the tire model 21 into contact with the road surface model 25 and calculates a rolling state in which the tire model 21 rolls relatively on the road surface model 25 (rolling step S3). ). FIG. 6 is a flowchart showing an example of the processing procedure of the rolling process.

In the rolling step S3 of the present embodiment, first, a boundary condition for bringing the tire model 21 shown in FIG. 4 into contact with the road surface model 25 and rolling is defined (step S31). The boundary conditions include, for example, the internal pressure condition of the tire model 21, the load-bearing condition L, the camber angle, and the coefficient of friction between the tire model 21 and the road surface model 25.

The boundary conditions of the present embodiment include the degree of freedom of the tire model 21. The degrees of freedom of the tire model 21 of the present embodiment are the degrees of freedom of translation (the degrees of freedom in the x-axis translation direction, the y-axis translation direction, and the z-axis translation direction) and the degree of freedom in the three-dimensional Cartesian coordinate system. The degrees of freedom (degrees of freedom in the x-axis rotation direction θx, the y-axis rotation direction θy, and the z-axis rotation direction θz) are included.

The boundary conditions of the present embodiment include the degrees of freedom of the road surface model 25. The degree of freedom of the road surface model 25 of the present embodiment includes the degree of freedom of translation (the degree of freedom in the x-axis translation direction, the y-axis translation direction, and the z-axis translation direction) in the three-dimensional Cartesian coordinate system.

The angular velocity V1 corresponding to the traveling speed (rolling speed V3) and the translational speed V2 are set as the boundary conditions of the present embodiment.

The angular velocity V1 is set on the rotation axis 28 (along the x-axis rotation direction θx) of the tire model 21. The rotation axis 28 is set, for example, by a line element (not shown) defined as non-deformable. The distance of the tire radius between the rotating shaft 28 and the rim model 27 (or the bead portion 24 shown in FIG. 5) is defined to be constant. In this embodiment, the rotation of the rim model 27 and the tire model 21 is calculated together with the rotation of the rotation shaft 28.

The translational speed V2 is set in the road surface model 25. The translation speed V2 of the present embodiment is set parallel to the y-axis (y-axis translation direction). The traveling speed (rolling speed V3) and the translational speed V2 are set as speeds on the surface (grounding surface 29) where the tire model 21 is in contact with the road surface model 25. These conditions are input to the computer 1 shown in FIG.

Next, in the rolling step S3 of the present embodiment, the tire model 21 (shown in FIG. 5) after the internal pressure filling is calculated (step S32). In step S32, first, as shown in FIG. 5, the bead portions 24 and 24 of the tire model 21 are restrained by the rim model 27 that models the rim 26 (shown in FIG. 2) of the tire 11. Further, the tire model 21 is deformed and calculated based on the evenly distributed load w corresponding to the internal pressure condition. As a result, the tire model 21 after filling the internal pressure is calculated. For the internal pressure, for example, it is desirable that the air pressure defined by each standard is set in the standard system including the standard on which the tire 11 (shown in FIG. 2) is based.

The deformation calculation (including the rolling calculation described later) of the tire model 21 is based on the shape and material properties of each element F (i), and the mass matrix, rigidity matrix, and damping of each element F (i). Each matrix is created. Furthermore, each of these matrices is combined to form the matrix of the entire system. Then, the equations of motion are created by applying the various conditions, and these are calculated for each minute time (unit time T (x) (x = 0, 1, ...)). As a result, the deformation of the tire model 21 is calculated.

Commercially available finite element analysis application software such as LS-DYNA manufactured by LSTC is used for the deformation calculation (including the rolling calculation described later) of the tire model 21. The unit time T (x) is appropriately set according to the required simulation accuracy.

Next, in the rolling step S3 of the present embodiment, the tire model 21 after the load is calculated (step S33). In step S33, first, as shown in FIG. 4, the contact between the tire model 21 after the internal pressure filling and the road surface model 25 is calculated. In the present embodiment, the road surface model 25 is moved toward the tire model 21 side (z-axis direction) with respect to the tire model 21 in which the degrees of freedom of the rotating shaft 28 (translational degree of freedom and rotational degree of freedom) are constrained. There is. Thereby, the contact between the tire model 21 and the road surface model 25 can be calculated.

In this embodiment, the rotation axis 28 of the tire model 21 is set to be parallel to the x-axis (x-axis translation direction). As a result, the straight direction of the tire model 21 is set parallel to the y-axis (y-axis translation direction). Further, the slip angle (not shown) of the tire model 21 is set to zero.

Next, in step S33, the deformation of the tire model 21 is calculated based on the load-bearing condition L, the camber angle (zero in this example), and the friction coefficient. As a result, in step S33, the tire model 21 after the load applied to the road surface model 25 is calculated.

Next, in the rolling step S3 of the present embodiment, the rolling state of the tire model 21 is calculated by allowing the degree of freedom of the road surface model 25 in the lateral direction intersecting the straight direction of the tire model 21 (first). 1 Rolling step S34).

In the first rolling step S34 of the present embodiment, first, the degree of freedom of translation of the tire model 21 (rotation axis 28) (the degree of freedom in the x-axis translation direction, the y-axis translation direction, and the z-axis translation direction), and , The degree of freedom in the y-axis rotation direction θy and the z-axis rotation direction θz is constrained. On the other hand, the degree of freedom in the x-axis rotation direction θx is allowed. As a result, the tire model 21 capable of linearly rolling toward the y-axis (y-axis translational direction) is set.

The road surface model 25 allows translational degrees of freedom (x-axis translational direction, y-axis translational direction, and z-axis translational degree of freedom).

Next, in the first rolling step S34 of the present embodiment, as shown in FIG. 4, the angular velocity V1 is set on the rotating shaft 28 of the tire model 21. Further, a translational speed V2 is set in the road surface model 25. As a result, the tire model 21 rolling straight on the road surface model 25 toward the y-axis (y-axis translational direction) is calculated.

In the present embodiment, the road surface model 25 is moved toward the tire model 21 (in the z-axis translational direction) for a unit time so that the load-bearing condition L is constant with respect to the tire model 21 elastically deformed during rolling. It is moved as appropriate for each.

As the rolling conditions of the tire model 21, for example, free rolling, braking, driving and the like can be appropriately set according to the running state of the tire 11 (shown in FIG. 2). These rolling conditions can be easily set by adjusting, for example, the angular velocity V1 of the tire model 21.

In the first rolling step S34, the rolling state of the tire model 21 is calculated until a predetermined end condition is satisfied. The end conditions are appropriately set, and for example, the number of rolling times of the tire model 21 shown in FIG. 3, the calculation end time, and the like are set.

In the first rolling step S34, the physical quantity (for example, wear energy) of the rolling tire model 21 is calculated. The physical quantity may be calculated, for example, at regular intervals (unit time), or may be calculated at a predetermined timing. The physical quantity is stored in the computer 1.

By the way, in general, even if the slip angle and the camber angle are zero, the rolling tire 11 (shown in FIG. 2) is affected by the belt plies 17A and 17B (belt cord inclination), structural asymmetry, and the like. , A small lateral force (residual lateral force) is generated between the road surface (not shown). Examples of the residual lateral force include price tear and conicity. It is believed that such residual lateral force is removed, for example, by the driver driving the vehicle on which the tire 11 is mounted by giving the tire 11 a slip angle.

On the other hand, also in the tire model 21 (shown in FIGS. 4 and 5), the internal structure of the belt plies 17A, 17B and the like of the tire 11 shown in FIG. 2 and the tread pattern are accurately reproduced. Therefore, when the rolling calculation of the tire model 21 is performed, the residual lateral force F1 (shown in FIG. 4 as an example) as described above may be generated (calculated). Therefore, when analyzing the rolling state of the ideal tire model 21, the tire wear, etc., the rolling state of the tire model 21 is calculated by removing the influence of the residual lateral force F1 as described above. Is desirable.

In the first rolling step S34 of the present embodiment, the road surface model 25 is free in the lateral direction (in this example, the x-axis translation direction) intersecting the straight direction (in this example, the y-axis translation direction) of the tire model 21. Degrees of freedom are allowed. As a result, in the first rolling step S34, the road surface model 25 is subjected to the lateral direction (that is, the residual lateral force) according to the residual lateral force F1 (shown in FIG. 4 as an example) generated in the tire model 21 in the rolling state. It can be relatively moved in the direction indicated by the arrow representing F1).

In the simulation method of the present embodiment, the residual lateral force F1 generated in the tire model 21 in the rolling state is removed (offset) by the lateral movement of the road surface model 25 in the lateral direction, and the tire model 21 is rolled. It is possible to calculate the dynamic state. Thereby, in the simulation method of the present embodiment, the rolling state of the tire model 21 can be calculated by removing the residual lateral force F1 as in the case of the tire 11 actually rolling (shown in FIG. 2). Therefore, the simulation method of the present embodiment can analyze the rolling state of the ideal tire model 21, the wear of the tire 11, and the like.

The contact patch 29 (shown in FIG. 4) of the tire model 21 during rolling changes with the elastic deformation of the tire model 21. Due to such a change in the contact patch 29, the residual lateral force F1 generated in the tire model 21 also changes from moment to moment (every unit time).

In the first rolling step S34 of the present embodiment, the road surface model 25 can be relatively moved in the lateral direction according to the residual lateral force F1 (size and direction) generated in the tire model 21 in the rolling state. As a result, in the first rolling step S34, the residual lateral force F1 that changes from moment to moment can be reliably removed. Therefore, for example, the slip angle of the tire model 21 for removing the residual lateral force F1 (not shown). Does not need to be calculated for each unit time. Therefore, the simulation method of the present embodiment can accurately calculate the rolling state of the tire model 21 (tire 11 shown in FIG. 2) while preventing an increase in calculation cost.

The first rolling step S34 may be performed on the tire model 21 after the wear of the tread portion 21a of the tire model 21. The worn tire model 21 has, for example, a node 31 constituting the outer surface 22s of the tread portion 21a of the tire model 21 shown in FIG. 5 based on the method described in Patent Document (Japanese Patent Laid-Open No. 2019-121335). , Can be calculated by moving inward in the radial direction of the tire.

The contact patch 29 (shown in FIG. 4) of the tire model 21 during rolling changes with the progress of wear of the tire model 21. Due to such a change in the contact patch 29, the residual lateral force F1 (shown in FIG. 4) generated in the tire model 21 also changes from moment to moment (every unit time).

In the first rolling step S34 of the present embodiment, the road surface model 25 can be relatively moved in the lateral direction according to the residual lateral force F1 (size and direction) generated in the tire model 21 in the rolling state. As a result, in the first rolling step S34, the residual lateral force F1 that changes from moment to moment can be reliably removed. Therefore, for example, the slip angle (not shown) of the tire model 21 for removing the residual lateral force F1 is set. , No need to calculate every unit time. Therefore, the simulation method of the present embodiment can accurately analyze the wear of the tire 11 (shown in FIG. 2) while preventing an increase in calculation cost.

Next, as shown in FIG. 3, in the simulation method of the present embodiment, it is determined whether or not the rolling state of the tire model 21 (shown in FIG. 4) is good (step S4). In step S4, whether or not the rolling state is good can be appropriately determined. For example, the quality of the rolling state can be determined by comparing the physical quantity of the tire model 21 during rolling with a predetermined threshold value for the physical quantity. The threshold value can be appropriately set based on the performance or the like required for the tire 11 (shown in FIG. 2).

When it is determined in step S4 that the rolling state of the tire model 21 (shown in FIG. 4) is good (“Y” in step S4), the tire 11 (FIG. 2) is based on the design factor of the tire model 21. (Shown in) is designed and manufactured (step S5). On the other hand, when it is determined in step S4 that the rolling state of the tire model 21 is not good (“N” in step S4), at least one of the design factors of the tire model 21 (tire 11) is changed (step S6). , Steps S1 to S4 are carried out again. As described above, in the simulation method of the present embodiment, the design factor is changed until the rolling state becomes good, so that the tire 11 having a good rolling state can be reliably designed and manufactured.

As shown in FIG. 4, in the first rolling step S34, the road surface model 25 is free in the lateral direction (in this example, the x-axis translation direction) intersecting the straight direction (in this example, the y-axis translation direction). The rolling state of the tire model 21 is calculated, allowing degrees of freedom. In such a first rolling step S34, at the start of rolling of the tire model 21, the vibration of the road surface model 25 in contact with the tire model 21 tends to increase due to the elastic deformation of the tire model 21.

The vibration of the road surface model 25 affects the physical quantity calculated in the first rolling step S34. In order to suppress such vibration, the rolling step S3 constrains the degree of freedom of the road surface model 25 in the lateral direction (in this example, the x-axis translational direction) prior to the first rolling step S34. , A second rolling step S35 (shown in FIG. 7) for calculating the rolling state of the tire model 21 may be included. FIG. 7 is a flowchart showing an example of the processing procedure of the rolling step S3 of another embodiment of the present invention. In this embodiment, the same configurations as those in the previous embodiments are designated by the same reference numerals, and the description thereof may be omitted.

In the second rolling step S35 of this embodiment, first, as in the first rolling step S34, among the degrees of freedom defined in the tire model 21 (rotation axis 28), the degree of freedom in the x-axis rotation direction θx is Allowed and other degrees of freedom constrained.

In the second rolling step S35 of this embodiment, unlike the first rolling step S34, among the degrees of freedom defined in the road surface model 25, the straight direction of the tire model 21 (in this example, the y-axis translation direction). The degree of freedom in the lateral direction (in this example, the x-axis translational direction) intersecting with is constrained. Other degrees of freedom of the road surface model 25 (in this example, the y-axis translation direction and the z-axis translation direction) are allowed.

Next, in the second rolling step S35 of this embodiment, as in the first rolling step S34, the road surface model 25 is directed toward the y-axis (y-axis translation direction) based on the angular velocity V1 and the translational velocity V2. The tire model 21 rolling straight on the top is calculated. The rolling conditions of the tire model 21 (for example, free rolling, braking, driving, etc.) can be appropriately set as in the first rolling step S34. In the second rolling step S35, the road surface model 25 is moved toward the tire model 21 (in the z-axis translational direction) so that the load-bearing condition L is constant with respect to the tire model 21 elastically deformed during rolling. , It is moved appropriately every unit time.

In the second rolling step S35 of the present embodiment, the road surface model 25 is free in the lateral direction (in this example, the x-axis translation direction) intersecting the straight direction (in this example, the y-axis translation direction) of the tire model 21. The rolling state of the tire model 21 is calculated by constraining the degrees. As a result, in the second rolling step S35, the vibration of the road surface model 25, which tends to be large at the start of rolling of the tire model 21, is suppressed as compared with the case where all the degrees of freedom in the translational direction of the road surface model 25 are allowed. be able to.

Then, in the rolling step S3 of this embodiment, in the first rolling step S34 to be carried out next, the vibration is suppressed in the lateral direction (in this example, the x-axis translational direction) with respect to the road surface model 25. The degree of freedom of the road surface model 25 is allowed. As a result, in the first rolling step S34, the lateral degree of freedom of the road surface model 25 is allowed while the tire model 21 is being rolled, so that the road surface model tends to be large at the start of rolling of the tire model 21. The vibration of 25 can be effectively prevented. Therefore, in the first rolling step S34, the rolling state of the tire model 21 from which the residual lateral force F1 has been removed can be stably calculated, and the influence of vibration on the physical quantity of the tire model 21 can be minimized. ..

In order to more reliably suppress the vibration of the road surface model 25 in the first rolling process S34, it was determined in the rolling process S3 that the vibration of the road surface model 25 is suppressed in the second rolling process S35. Later, the first rolling step S34 may be carried out. Whether or not the vibration of the road surface model 25 is suppressed can be appropriately determined by, for example, the computer 1. As an example, when the amplitude of the vibration of the road surface model is lower than a predetermined threshold value, it can be determined that the vibration of the road surface model 25 is suppressed.

In the second rolling step S35, the degree of freedom of the road surface model 25 in the lateral direction (in this example, the x-axis translational direction) is restricted, so that the residual lateral force F1 is applied as in the first rolling step S34. Can't be removed. Therefore, in the second rolling step S35, the tire model 21 may be provided with a slip angle so that the residual lateral force F1 of the tire model 21 becomes zero or small. FIG. 8 is a plan view showing an example of the tire model 21 given the slip angle θ1.

As a result, in the rolling step S3, in the second rolling step S35, the first rolling step S34 uses the road surface model 25 in which vibration is suppressed and the tire model 21 in which the residual lateral force F1 is removed. Will be implemented. In the first rolling step S34, it is desirable that the slip angle θ1 is set to zero. Therefore, in the first rolling step S34, it is possible to reliably remove the residual lateral force F1 and calculate the rolling state of the tire model 21.

In the second rolling step S35 of this embodiment, it is desirable that the slip angle θ1 of the tire model 21 is calculated for each unit time. In the second rolling step S35, it is possible to suppress an increase in calculation cost such as a slip angle θ1 by performing the second rolling step S35 only until the vibration of the road surface model 25 is suppressed.

Although the particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified into various embodiments.

A simulation for calculating the rolling state of the tire model was carried out based on the processing procedure shown in FIG. 4 (Example 1 and Example 2).

In the rolling process of the first embodiment, the rolling state of the tire model is calculated by allowing the degree of freedom of the road surface model in the lateral direction intersecting the straight direction of the tire model based on the processing procedure shown in FIG. The first rolling step was carried out. This first rolling step was performed on a tire model after wear (wear progress) in which the tread portion of the tire model was worn.

On the other hand, in the rolling step of the second embodiment, based on the processing procedure shown in FIG. 7, prior to the first rolling step, the degree of freedom of the road surface model in the lateral direction is restricted, and the rolling state of the tire model is restrained. The second rolling step for calculating the above and the first rolling step described above were carried out. The second rolling step was performed in a state where the tire model was given a slip angle so that the residual lateral force of the tire model was zero or small.

For comparison, the rolling state of the tire model was calculated by constraining (not allowing) the degree of freedom of the road surface model in the lateral direction (Comparative Example 1, Comparative Example 2). The calculation of the rolling state of Comparative Example 1 and Comparative Example 2 was performed on a tire model after wear (wear progressed) in which the tread portion of the tire model was worn.

In Comparative Example 1, the rolling of the tire model in which the slip angle was set to zero was calculated. On the other hand, in Comparative Example 2, the initial slip angle was given to the tire model so that the residual lateral force became zero or small at the start of rolling of the tire model, but the residual stress did not increase or decrease thereafter. , The initial slip angle was maintained.

Wear energy was calculated for all the elements constituting the ground plane of each tread portion of Example 1, Example 2, Comparative Example 1 and Comparative Example 2. Then, in the center rib, the left and right middle ribs, and the left and right shoulder ribs, the average value (average wear energy) of the wear energy of the elements constituting each rib was calculated. The common specifications are as follows.
Tire size: 275 / 80R22.5
Internal pressure: 900 kPa
Load: 30.72kN
Camber angle: Zero tread tread pattern (5 ribs (symmetrical with respect to the equator of the tire))
Center rib: 1 on the equator of the tire Middle rib: 1 on each side of the shoulder rib in the tire axial direction Shoulder rib: 1 on each side of the middle rib in the tire axial direction

FIG. 9 is a graph showing the laterality of the average wear energy of the tire model after wear progress. FIG. 10 is a graph showing the average wear energy of each rib of the tread portion. In FIGS. 9 and 10, the value at the time when the average amount of wear of the tread portion from the time of new product (before wear) is 1 mm is exemplified.

In a tire model in which the camber angle is set to zero and the tread pattern is symmetrical, the laterality of the average wear energy needs to be calculated to be small. However, as the residual lateral force of the rolling tire model increases, the laterality of the average wear energy tends to increase. As shown in FIG. 9, in Example 1 and Example 2, the laterality of the average wear energy can be made smaller than that of Comparative Example 1 and Comparative Example 2, and the residual lateral force of the tire model is removed. I was able to calculate the rolling state of the tire model.

Further, when the vibration of the road surface model becomes large, the average wear energy of the tire model tends to be calculated more than necessary. As shown in FIG. 10, in Example 2, the average wear energy could be made smaller than that in Example 1, and the average wear energy of the actual tire could be approximated. Therefore, in Example 2, the influence of vibration on the physical quantity of the tire model could be minimized as compared with Example 1.

21 Tire model 25 Road surface model

Claims (4)

It ’s a tire simulation method.
The process of inputting a tire model that models the tire into a computer,
The process of inputting a road surface model that models the road surface on which the tires roll into the computer, and
The computer includes a rolling step of bringing the tire model into contact with the road surface model and calculating a rolling state in which the tire model rolls relatively on the road surface model.
The rolling step includes a first rolling step of calculating the rolling state of the tire model, allowing the degree of freedom of the road surface model in the lateral direction intersecting the straight direction of the tire model.
Tire simulation method. The first aspect of the present invention, wherein the rolling step includes a second rolling step of constraining the degree of freedom of the road surface model and calculating the rolling state of the tire model prior to the first rolling step. Tire simulation method. The tire simulation method according to claim 2, wherein the second rolling step is performed in a state where a slip angle is given to the tire model so that the residual lateral force of the tire model becomes zero or small. The tire simulation method according to any one of claims 1 to 3, wherein the first rolling step is performed on a tire model after wear in which the tread portion of the tire model is worn.

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