JP6502679B2 - Tire simulation method and simulation apparatus - Google Patents

Description

  The present invention relates to a simulation method and a simulation apparatus capable of predicting the wear performance of a tire.

  Conventionally, various measurement devices for predicting the wear performance (for example, the amount of wear) of a tire have been proposed. A measuring device of this type includes, for example, a ground base for rolling a tire, a sensor for measuring the wear energy of a tire provided on the ground base, a camera for photographing the ground contact shape of a tire, etc. Is provided.

JP 2001-1723 A

  A smooth transparent material such as glass, for example, which can transmit the contact shape of the tire, is used for the contact stand. However, the coefficient of friction of the glass is different from the coefficient of friction of the road surface on which the tire travels. Therefore, with such a measuring device, it has been difficult to accurately predict the wear performance of the tire.

  Furthermore, the wear energy of the tire is measured at any position of the tread portion of the tire. For this reason, there is a problem that the wear performance of the actual tire which wears continuously in the tire circumferential direction can not be accurately predicted.

  The present invention has been made in view of the above-described actual situation, and its main object is to provide a simulation method and a simulation apparatus capable of accurately predicting the wear performance of a tire.

The present invention is a method for predicting, using a computer, the wear performance of at least one tread small area continuous in the tire circumferential direction of a tread portion of a tire, the computer comprising a finite number of elements of the tire. And a step of inputting a tire model modeled in at least one of the tire model running the tire model under at least two or more rolling conditions of free rolling, braking, driving, and turning. In the tread small area , the average wear of a unit time obtained by dividing the integrated value of the wear energy calculated for each of the finite number of elements from the ground contact to the ground contact end of the tread small area by the ground area of the tread small area The energy is determined, and the integrated value of the average wear energy of the unit time from the rolling start to the rolling end of the tire model, Average wear energy from Kitendo start divided by total time until the rolling ends, the step of calculating for each rolling condition, the computer, on the basis of the average wear energy for each of the rolling conditions, the Condition-specific wear performance calculation step of calculating the condition-specific wear performance of the tread small area of the tire, the occurrence frequency calculation step of acquiring the occurrence frequency of each rolling condition for the travel history of the vehicle provided in advance by the computer And the computer calculates the wear performance by condition under each rolling condition by the occurrence frequency in the small tread area of the tire, and the tread when the tire travels in the travel history Calculating the small area predicted wear performance.

In the tire simulation method according to the present invention, the occurrence frequency calculating step causes the tire to travel to obtain actual wear performance of the small tread area, and actual wear performance of the small tread area of the tire. It is desirable to include the step of calculating the frequency of occurrence of each rolling condition by multiple regression analysis based on the average wear energy of the small tread portion of the tire model.

  In the tire simulation method according to the present invention, the generation frequency calculation step includes the steps of: running the tire to obtain the occurrence frequency of left and right acceleration and front and rear acceleration; and the left and right acceleration and the front and rear acceleration. It is desirable to include the step of acquiring the frequency of occurrence of each rolling condition based on the frequency of occurrence of.

  In the tire simulation method according to the present invention, the condition-specific wear performance calculation step is a step of acquiring the wear amount and wear energy of the rubber material of the tread small area of the tire, the rubber material in the tread small area Obtaining the wear index indicating the relationship between the amount of wear of the rubber material and the wear energy of the rubber material, and the rolling based on the wear index of each rubber material and the average wear energy of the small tread area It is desirable to include the step of calculating the condition-specific wear performance of the small tread area for each condition.

In the tire simulation method according to the present invention, it is preferable that the wear index shows a relationship in which the wear amount of the rubber material changes in a non-linear manner due to a change in wear energy of the rubber material.

In the tire simulation method according to the present invention, the tread portion is provided with at least one longitudinal land portion divided by circumferential grooves continuously extending in the tire circumferential direction,
Preferably, the tread small area of the tire is set to the longitudinal land portion.

  In the tire simulation method according to the present invention, the tire model has a longitudinal land model obtained by modeling the longitudinal land, and the small tread portion of the tire model is set to the longitudinal land model. Is desirable.

The present invention is a tire simulation device having an arithmetic processing unit for predicting the wear performance of at least one tread small area continuous in the tire circumferential direction of a tread portion of a tire, wherein the arithmetic processing unit limits the tire. A tire model setting unit configured to set a tire model modeled by a plurality of elements, running the tire model under at least two or more rolling conditions of free rolling, braking, driving, and turning, the tire model In the small tread area , the integrated value of the wear energy calculated for each of the finite number of elements from the bottom to the ground end of the small tread area divided by the ground area of the small tread area is an average of unit time The wear energy is determined, and the product of the average wear energy of the unit time from the rolling start to the rolling end of the tire model Values, the average wear energy obtained by dividing the total time until the rolling termination from the rolling start, the average wear energy calculation unit for calculating for each rolling condition, on the basis of the average wear energy, each of the rolling conditions A condition-specific wear performance calculation unit for calculating the condition-specific wear performance of the small tread region of the tire; a generation frequency calculation unit for acquiring the occurrence frequency of each rolling condition with respect to the traveling history of the vehicle provided in advance; In the tread small area of the tire, the wear performance by condition under each rolling condition is weighted according to the occurrence frequency, and predicted wear of the tread small area when the tire travels in the traveling history It is characterized by including a wear performance calculation unit that calculates the performance.

  The tire simulation method of the present invention comprises the steps of: inputting a tire model obtained by modeling a tire with a finite number of elements in a computer; and at least two of the free rolling, braking, driving and turning of the computer. The method includes running the tire model under one or more rolling conditions and calculating an average wear energy of a small tread area of the tire model for each rolling condition.

  In the tire simulation method of the present invention, the condition-specific wear performance calculation step of calculating the condition-specific wear performance of the small tread region of the tire for each rolling condition based on the average wear energy, the vehicle running provided in advance. About the history, the occurrence frequency calculation process of acquiring the occurrence frequency of each rolling condition, and the wear performance by condition of each rolling condition in the small tread area of the tire are weighted by the occurrence frequency, and the running history is Calculating the predicted wear performance of the small tread area as the tire is driven.

  Thus, according to the simulation method of the present invention, the tire model can be made to travel by approximating an actual tire based on, for example, the coefficient of friction between the actual tire and the road surface by simulation using a computer. . Therefore, the average wear energy of the tire model can be calculated with high accuracy. In addition, the predicted wear performance of the small tread region can be evaluated by evaluating the wear performance of the tire with high accuracy, since the wear performance by conditions for each rolling condition is obtained by weighting with the occurrence frequency of each rolling condition. it can.

  Furthermore, since the predicted wear performance of the small tread area is calculated based on the average wear energy calculated for all elements of the small tread area of the tire model, the actual wear resistance of the tire continuously in the circumferential direction of the tire The wear performance can be accurately approximated. Further, in the case where a plurality of small tread regions are set, predicted wear performance, average wear energy and wear characteristics according to conditions can be obtained for each small tread region, so that the wear performance of the tire can be evaluated in detail. Therefore, the tire simulation method of the present invention can accurately predict the wear performance of the tire.

It is a block diagram of a computer by which the simulation method of this embodiment is implemented. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the tire by which wear performance is estimated by the simulation method of this embodiment. It is a tread development view of the tire of FIG. It is a flowchart which shows an example of the process sequence of the simulation method of this embodiment. It is a sectional view of a tire model of this embodiment. It is a tread developed view of FIG. It is a perspective view of a tire model and a road surface model of this embodiment. It is a flowchart which shows an example of the process sequence of the 1st abrasion energy calculation process of this embodiment. It is a contour figure which shows the wear energy at the time of free rolling. It is a flowchart which shows an example of the process sequence of the abrasion performance calculation process according to conditions of this embodiment. It is a graph which shows an example of the wear index of this embodiment. It is a flowchart which shows an example of the process sequence of the generation frequency calculation process of this embodiment. It is a graph which shows the actual abrasion loss of each circumferential direction slot. It is a graph which shows the average wear energy of each circumferential direction groove model and tread tread end which were shown for every rolling condition for every rolling condition. It is a flowchart which shows an example of a process sequence of the generation frequency calculation process of other embodiment of this invention. It is a graph which shows the generation frequency of the acceleration on either side. It is a graph which shows the generation frequency of acceleration before and behind. It is a graph which shows an example of the abrasion index of other embodiment of this invention. It is a graph which shows the relationship of the estimated amount of wear and the amount of actual wear about Example 1 and a comparative example. It is a graph which shows the relationship of the estimated amount of wear and the amount of actual wear about Example 2 and a comparative example.

Hereinafter, an embodiment of the present invention will be described based on the drawings.
The tire simulation method of the present embodiment (hereinafter sometimes referred to simply as “simulation method”) is a method for predicting the wear performance of a tire using a computer. The wear performance predicted by the simulation method of the present embodiment is the wear amount of the tire, but may be, for example, an index or the like indicating the magnitude of the wear amount.

  FIG. 1 is a block diagram of a computer 1 in which the simulation method of the present embodiment is implemented. The computer 1 according to the present embodiment includes an input unit 11 as an input device, an output unit 12 as an output device, and an arithmetic processing unit 13 for calculating a physical quantity of a tire, etc., and is a simulation device for predicting tire wear performance. It is configured as 1A.

  For example, a keyboard or a mouse is used as the input unit 11. For example, a display device or a printer is used as the output unit 12. The arithmetic processing unit 13 includes an arithmetic unit (CPU) 13A that performs various operations, a storage unit 13B that stores data, programs, and the like, and a work memory 13C.

  The storage unit 13B is, for example, a non-volatile information storage device made of a magnetic disk, an optical disk, an SSD, or the like. A data unit 15 and a program unit 16 are provided in the storage unit 13B.

  The data unit 15 includes an initial data unit 15A in which information on a tire to be evaluated and a road surface (for example, CAD data etc.) is stored, a tire model input unit 15B in which a tire model obtained by modeling a tire is input, and a tire A road surface model input unit 15C to which a road surface model that models a road surface to be rolled is input is included. The data unit 15 further includes a boundary condition input unit 15D to which boundary conditions of simulation are input, and a physical quantity input unit 15E to which physical quantities calculated by the calculation unit 13A are input.

  The program unit 16 is a program executed by the operation unit 13A. The program unit 16 includes a tire model setting unit 16A that sets a tire model, a road surface model setting unit 16B that sets a road surface model, an internal pressure filling calculation unit 16C that calculates the shape of the tire model after internal pressure filling, and after internal pressure filling A load calculation unit 16D is included which defines the load in the tire model of (1). Furthermore, the program unit 16 is configured to include an average wear energy calculation unit 16E, an occurrence frequency calculation unit 16F, a condition-specific wear performance calculation unit 16G, and a wear performance calculation unit 16H.

  FIG. 2 is a cross-sectional view of the tire 2 for which wear performance is predicted by the simulation method of the present embodiment. FIG. 3 is a development view of a tread of the tire 2 of FIG. The tire 2 of the present embodiment includes a carcass 6 extending from the tread portion 2a through the sidewall portion 2b to the bead core 5 of the bead portion 2c, and a belt layer disposed outside the carcass 6 in the tire radial direction and inside the tread portion 2a. And 7 are provided.

  The tread portion 2a of the present embodiment is provided with a circumferential groove 9 extending continuously in the tire circumferential direction. Thus, the tread portion 2 a is provided with a plurality of longitudinal land portions 10 divided by the circumferential grooves 9.

  The circumferential grooves 9 in the present embodiment include a pair of center circumferential grooves 9a and 9b disposed on both sides in the tire axial direction of the tire equator C, and the center circumferential grooves 9a and 9b and the tread contact end 2t. A pair of shoulder circumferential grooves 9c, 9d disposed between them is included. A pair of center circumferential grooves 9a and 9b are disposed at a first center circumferential groove 9a disposed on one side Sa in the tire axial direction with respect to the tire equator C, and on the other side Sb in the tire axial direction A distinction is made between the two center circumferential grooves 9b. A pair of shoulder circumferential grooves 9c, 9d is disposed at a first shoulder circumferential groove 9c disposed on one side Sa in the tire axial direction with respect to the tire equator C, and at the other side Sb in the tire axial direction The two shoulder circumferential grooves 9d are distinguished.

  The longitudinal land portion 10 has a pair of middle longitudinal land portions 10a divided between a pair of center circumferential grooves 9a and 9b, a pair of middle circumferential grooves 9a and 9b, and a pair of middle shoulder grooves 9c and 9d. It includes a pair of shoulder land portions 10d, 10e divided by the land portions 10b, 10c and the shoulder circumferential grooves 9c, 9d and the tread contact end 2t. In each longitudinal land portion 10a to 10e, a lateral groove 20 or the like that intersects the circumferential groove 9a to 9d or the tread ground contact end 2t is provided.

  The pair of middle longitudinal land portions 10b and 10c are disposed at the first middle longitudinal land portion 10b disposed on the one side Sa in the tire axial direction with respect to the tire equator C, and at the other side Sb in the tire axial direction 2 middle middle land portion 10 c is distinguished. The pair of shoulder longitudinal land portions 10d and 10e are disposed at the first shoulder longitudinal land portion 10d disposed on the one side Sa in the tire axial direction with respect to the tire equator C, and at the other side Sb in the tire axial direction. It is divided into two shoulder land portions 10e.

  In the present specification, “tread ground contact end 2t” means that tire 2 which is rim-assembled on a regular rim and filled with regular internal pressure is loaded with a regular load and grounded to a flat surface at a camber angle of 0 degrees It is the outermost end in the tire axial direction of the tread contact surface.

  The “regular rim” is a rim that defines the standard for each tire in the standard system including the standard on which the tire is based, for example, “standard rim” for JATMA, “Design Rim” for ETRA, and TRA In the case of "Measuring Rim".

  The "normal internal pressure" is the air pressure specified by each standard in the standard system including the standard to which the tire is based, and in the case of JATMA, the "maximum air pressure", and in the case of TRA, the table "TIRE LOAD LIMITS The maximum value described in “AT VARIOUS COLD INFlation PRESSURES”, “INFLATION PRESSURE” for ETRTO, and 180 kPa for tires for passenger cars.

  The “normal load” is the load specified for each tire in the above standard, maximum load capacity in the case of JATMA, maximum value described in the table “TIRE LOAD LIMITS AT VARIOUS COLD INFlation PRESSURES” in the case of TRA, ETRTO If it is "LOAD CAPACITY".

  Further, in the tire 2, a tread small area 18 virtually divided by the tread portion 2a is set. The small tread region 18 of the present embodiment is a region continuous in the tire circumferential direction. Such a small tread area 18 may be appropriately set according to, for example, the tread pattern of the tire 2 or the tire structure. The small tread region 18 of the present embodiment is set to each longitudinal land portion 10a to 10e divided by the circumferential grooves 9a to 9d.

  As shown in FIG. 2, the carcass 6 is constituted by at least one or more, in the present embodiment, one carcass ply 6A. In the carcass ply 6A, the main body portion 6a extending from the tread portion 2a through the sidewall portion 2b to the bead core 5 of the bead portion 2c and the main body portion 6a are folded back around the bead core 5 from the inside in the tire axial direction And the folded back portion 6b. A bead apex rubber 8 extending from the bead core 5 to the outer side in the tire radial direction is disposed between the main body portion 6a and the folded back portion 6b. In addition, the carcass ply 6A includes a carcass cord arranged at an angle of, for example, 75 degrees to 90 degrees with respect to the tire equator C.

  The belt layer 7 is configured by including two belt plies 7A and 7B outside the belt cords arranged at an angle of, for example, 10 degrees to 35 degrees with respect to the tire circumferential direction. The belt plies 7A and 7B are configured to overlap in the direction in which the belt cords cross each other.

  FIG. 4 is a flowchart illustrating an example of the processing procedure of the simulation method of the present embodiment. In the simulation method of the present embodiment, first, a tire model obtained by modeling the tire 2 shown in FIGS. 2 and 3 is set in the computer 1 (step S1).

  In step S1, first, as shown in FIG. 1, information (for example, contour data of the tire 2 etc.) related to the tire 2 (shown in FIG. 2) stored in the initial data section 15A is stored in the working memory 13C. It is input. Further, the tire model setting unit 16A is read into the work memory 13C. Then, the tire model setting unit 16A is executed by the computing unit 13A. FIG. 5 is a cross-sectional view of a tire model of the present embodiment. 6 is a development view of the tread of FIG. In FIG. 6, the mesh of the groove is omitted.

  In step S1, on the basis of the information on the tire 2 (shown in FIG. 2), the finite number of elements F (i) (i = 1, 2,...) That can be handled by numerical analysis are discretized. Thereby, a tire model 21 in which the tire 2 is modeled is set. The tire model 21 is stored in a tire model input unit 15B (shown in FIG. 1). As a numerical analysis method, for example, a finite element method, a finite volume method, a difference method or a boundary element method can be adopted as appropriate, but in the present embodiment, the finite element method is adopted.

  As the element F (i), for example, a tetrahedron solid element, a pentahedron solid element, or a hexahedron solid element is preferably used. Each element F (i) is provided with a plurality of nodes 25. In each of such elements F (i), numerical data such as an element number, a number of a node 25, coordinate values of the node 25 and material characteristics (for example, density, Young's modulus and / or damping coefficient) are defined.

  In the tread portion 21a of the tire model 21, a circumferential groove model 22 in which the circumferential groove 9 (shown in FIGS. 2 and 3) is reproduced and a longitudinal land portion 10 (shown in FIGS. 2 and 3) are reproduced. The longitudinal land model 23 is set. The circumferential groove model 22 includes a first center circumferential groove model 22a in which the first center circumferential groove 9a is reproduced, and a second center circumferential groove model 22b in which the second center circumferential groove 9b is reproduced. It is done. Further, the circumferential groove model 22 is a first shoulder circumferential groove model 22c in which the first shoulder circumferential groove 9c is reproduced, and a second shoulder circumferential groove model 22d in which the second shoulder circumferential groove 9d is reproduced. It is included.

  The longitudinal land model 23 is a center longitudinal land model 23a in which the center longitudinal land 10a is reproduced, a first middle longitudinal land model 23b in which the first middle longitudinal land 10b is reproduced, and a second middle longitudinal land. A second middle longitudinal land model 23c in which the section 10c is reproduced is included. Furthermore, as the longitudinal land model, a first shoulder longitudinal land model 23d in which the first shoulder longitudinal land 10d is reproduced and a second shoulder longitudinal land model 23e in which the second shoulder longitudinal land 10e is reproduced are used. include. In the present embodiment, the tread small area 30 of the tire model 21 is set by the longitudinal land models 23a to 23e.

  Next, in the simulation method of the present embodiment, a road surface model obtained by modeling a road surface is set in the computer 1 (step S2). In step S2, first, information on the road surface stored in the initial data unit 15A shown in FIG. 1 is input to the work memory 13C. Further, the road surface model setting unit 16B is read into the work memory 13C. Then, the road surface model setting unit 16B is executed by the calculation unit 13A.

  FIG. 7 is a perspective view of the tire model 21 and the road surface model 24 of the present embodiment. In FIG. 7, the mesh of the tire model 21 is omitted. In step S2, based on information on the road surface, discretization is performed using a finite number of elements G (i) (i = 1, 2,...) That can be handled by a numerical analysis method (in the present embodiment, finite element method). Thus, the road surface model 24 is set in step S2. The road surface model 24 thus set is stored in the road surface model input unit 15C (shown in FIG. 1).

  The element G (i) consists of a rigid plane element set non-deformable. The element G (i) is provided with a plurality of nodes 28. Furthermore, in the element G (i), numerical data such as the element number and the coordinate value of the node 28 are defined.

  In the present embodiment, the road surface model 24 is exemplified as having a smooth surface, but if necessary, it may be an actual surface such as a minute unevenness such as an asphalt road surface, irregular steps, depressions, undulations, or wrinkles. Asperities similar to the traveling road surface may be provided.

  Next, in the simulation method of the present embodiment, the computer 1 causes the tire model 21 to travel and calculates the average wear energy of the small tread area 30 of the tire model 21 (average wear energy calculating step S3). The average wear energy calculating step S3 causes the tire model 21 to run under at least two or more rolling conditions of free rolling, braking, driving, and turning, and the average wear energy of the small tread area 30 rolls. Calculated for each condition. In the present embodiment, the tire model 21 is run under rolling conditions of free rolling, braking, driving, and turning.

  As described above, the tread small area 30 of the present embodiment is each longitudinal land model 23 a to 23 e. Therefore, in the average wear energy calculating step S3 of the present embodiment, the average wear energy of each longitudinal land model 23a to 23e is calculated. FIG. 8 is a flow chart showing an example of the processing procedure of the average wear energy calculation step S3.

  In the average wear energy calculation step S3, first, boundary conditions are defined in the tire model 21 (step S31). As shown in FIG. 7, as the boundary conditions, for example, the internal pressure condition of the tire model 21, the load condition T, the camber angle, and the coefficient of friction between the tire model 21 and the road surface model 24 are set. Further, as the boundary conditions, torque TL of the tire model 21, lateral force (not shown), and translational velocity V2 of the road surface model 24 corresponding to the traveling velocity V are set.

  In the rolling conditions of free rolling, braking, driving, and turning, a translational velocity V2 is set in the road surface model 24. Thereby, the tire model 21 which rolls based on the coefficient of friction between the tire model 21 and the road surface model 24 can be calculated.

  The torque TL is not defined in the tire model 21 under free rolling conditions. Under the braking condition, a torque TL corresponding to braking is set in the tire model 21. Under the drive condition, a torque TL corresponding to the drive is set to the tire model 21. Under turning conditions, lateral force (not shown) is set to the tire model 21. These conditions are stored in the boundary condition input unit 15D (shown in FIG. 1). A force corresponding to the torque TL or the like set in the tire model 21 may be set in the road surface model 24.

  Next, in the average wear energy calculating step S3, the shape after filling the internal pressure of the tire model 21 (shown in FIG. 5) is calculated (step S32). In step S32, as shown in FIG. 1, the tire model 21 stored in the tire model input unit 15B and the internal pressure conditions stored in the boundary condition input unit 15D are read into the working memory 13C. Further, the internal pressure filling calculation unit 16C is read into the working memory 13C. Then, the internal pressure filling calculation unit 16C is executed by the calculation unit 13A.

  In step S32, first, as shown in FIG. 5, the bead portions 21c and 21c of the tire model 21 are restrained by the rim model 27 in which the rim 26 (shown in FIG. 2) of the tire 2 is modeled. Further, the tire model 21 is subjected to deformation calculation based on the equally distributed load w corresponding to the internal pressure condition. Thereby, in step S32, the tire model 21 after internal pressure filling is calculated. As for the internal pressure, for example, in the standard system including the standard on which the tire 2 (shown in FIG. 2) is based, it is desirable that the air pressure specified by each standard be set.

  In the deformation calculation of the tire model 21, a mass matrix, a stiffness matrix, and a damping matrix of each element F (i) are respectively created based on the shape, material properties, and the like of each element F (i). Furthermore, each of these matrices is combined to create a matrix of the entire system. Then, the computer 1 applies the various conditions to create an equation of motion, and calculates deformation of the tire model 21 every minute time (unit time Tx (x = 0, 1,...)). Such deformation calculation (including rolling calculation described later) of the tire model 21 can be calculated using commercially available finite element analysis application software such as LS-DYNA manufactured by LSTC. The unit time Tx can be appropriately set according to the required simulation accuracy.

  Next, in the average wear energy calculation step S3, the tire model 21 in which the load is defined is calculated (step S33). In step S33, as shown in FIG. 1, the load condition, camber angle and friction coefficient stored in the boundary condition input unit 15D are read into the working memory 13C. Furthermore, in step S33, the load calculation unit 16D is read into the work memory 13C. Then, the load calculation unit 16D is executed by the calculation unit 13A.

  In step S33, as shown in FIG. 7, the contact between the tire model 21 after the internal pressure filling and the road surface model 24 is calculated. Next, in step S33, the deformation of the tire model 21 is calculated based on the applied load condition T, the camber angle (not shown), and the friction coefficient. Thus, in step S33, the tire model 21 in contact with the road surface model 24 is calculated.

  Next, in the average wear energy calculating step S3 of the present embodiment, the average wear energy of the small tread area 30 during free rolling is calculated (step S34). In step S32 of the present embodiment, at the time of free rolling of the tire model 21, the average wear energy of each longitudinal land model 23a to 23e (shown in FIG. 6) is calculated.

  In step S34, first, the translational velocity V2 stored in the boundary condition input unit 15D is read into the working memory 13C. Furthermore, in step S34, the average wear energy calculation unit 16E for calculating the average wear energy of the tire model 21 is read into the work memory 13C. Then, the average wear energy calculation unit 16E is executed by the calculation unit 13A.

  As shown in FIG. 7, in step S34, first, the translational velocity V2 is set to the road surface model 24. Thus, the tire model 21 rolling freely on the road surface model 24 can be calculated. As shown in FIG. 6, while each node 25 constituting each longitudinal land model 23a to 23e is in contact with the road surface model 24 (shown in FIG. 7), the shear force and the amount of slip at each node 25 Calculated The shear force P includes a shear force Px in the tire axial direction x and a shear force Py in the tire circumferential direction y. The slippage amount Q includes the slippage amount Qx in the tire axial direction x and the slippage amount Qy in the tire circumferential direction y, which correspond to the shear forces Px and Py.

  The free rolling calculation is calculated for each unit time Tx of simulation from the start of rolling to the end of predetermined rolling. As a result, in step S34, the shear forces Px and Py and the slip amounts Qx and Qy of each node 25 are calculated a plurality of times in increments of unit time Tx from the start of rolling to the end of rolling. FIG. 9 is a contour diagram showing the wear energy at the time of free rolling of each node 25. As shown in FIG. In the contour diagram, different color information is set for each wear energy of the same range based on the wear energy calculated at each node 25 and the wear energy interpolated from the wear energy of each node 25. Such contour map can be obtained, for example, by a general purpose post processor (such as LS-PrePost manufactured by LSTC).

  In step S34, the shear force Px (i), Py (i) at each nodal point 25 and the slip amount Qx (y) corresponding to the shear force Px (i), Py (i) in each longitudinal-land model 23a-23e. i) The value obtained by multiplying Qy (i) is integrated for the element F (i) from the bottom to the ground end of each of the longitudinal sections 23a to 23e. And the said integrated value of each longitudinal land model 23a-23e is remove | divided by the contact area of each longitudinal land model 23a-23e, and the average wear energy of unit time Tx is longitudinal land model 23a-23e. Calculated every time. Next, the average wear energy of unit time Tx is integrated from the start of rolling to the end of rolling, and the integrated value is divided by the total time from the start of rolling to the end of rolling. Thereby, the average wear energy at free rolling is calculated for each of the longitudinal land models 23a to 23e. The average wear energy of the longitudinal land models 23a to 23e at the time of free rolling is stored in the physical quantity input unit 15E.

  Next, in the average wear energy calculating step S3 of the present embodiment, the average wear energy of the tread small area 30 at the time of braking is calculated (step S35). At step S35 of the present embodiment, at the time of braking of the tire model 21, the average wear energy of each longitudinal land model 23a to 23e is calculated.

  In step S35, as shown in FIG. 1, the translational velocity V2, the torque TL corresponding to the time of braking, and the average wear energy calculation unit 16E stored in the boundary condition input unit 15D are read into the work memory 13C. Then, the average wear energy calculation unit 16E is executed by the calculation unit 13A.

  In step S35, as shown in FIG. 7, the translational velocity V2 is set to the road surface model 24. In this way, the tire model 21 rolling freely on the road surface model 24 can be calculated. Next, the torque TL at the time of braking is set to the tire model 21. Thereby, the tire model 21 braked from the freely rolling state can be calculated. In step S35, the shear forces Px and Py and the slip amounts Qx and Qy of the node 25 are calculated a plurality of times in unit time Tx intervals from the start of braking to the end of braking.

  In step S35, the average wear energy at the time of braking is calculated for each of the longitudinal land models 23a to 23e by the same calculation method as in step S34. The average wear energy of each longitudinal land model 23a-23e at the time of braking is stored in the physical quantity input unit 15E.

  Next, in the average wear energy calculation step S3 of the present embodiment, the average wear energy of the small tread area 30 at the time of driving is calculated (step S36). In step S36 of the present embodiment, when the tire model 21 is driven, the average wear energy of the longitudinal land models 23a to 23e is calculated.

  In step S36, as shown in FIG. 1, the translational velocity V2 stored in the boundary condition input unit 15D, the torque TL during driving, and the average wear energy calculation unit 16E are read into the working memory 13C. Then, the average wear energy calculation unit 16E is executed by the calculation unit 13A.

  In step S36, as shown in FIG. 7, the translational velocity V2 is set to the road surface model 24. In this way, the tire model 21 rolling freely on the road surface model 24 can be calculated. Next, the torque TL at the time of driving is set to the tire model 21. As a result, the tire model 21 driven from the freely rolling state can be calculated. In step S36, the shear forces Px and Py and the slip amounts Qx and Qy of the node 25 are calculated a plurality of times in unit time Tx intervals from the drive start to the drive end.

  In step S36, the average wear energy at the time of driving is calculated for each of the longitudinal land models 23a to 23e by the same calculation method as in step S34. The average wear energy of each longitudinal land model 23a-23e at the time of driving is stored in the physical quantity input unit 15E.

  Next, in the average wear energy calculating step S3 of the present embodiment, the average wear energy of the tread small area 30 at the time of turning is calculated (step S37). In step S37 of the present embodiment, when the tire model 21 is turned, the average wear energy of the longitudinal land models 23a to 23e is calculated.

  In step S37, as shown in FIG. 1, the translational velocity V2, the lateral force (not shown) and the average wear energy calculation unit 16E stored in the boundary condition input unit 15D are read into the working memory 13C. Then, the average wear energy calculation unit 16E is executed by the calculation unit 13A.

  In step S37, as shown in FIG. 7, the translational velocity V2 is set to the road surface model 24. In this way, the tire model 21 rolling freely on the road surface model 24 can be calculated. Next, lateral force (not shown) is set to the tire model 21. Thereby, the tire model 21 that has been turned from the freely rolling state can be calculated. In step S37, the shear forces Px and Py and the slip amounts Qx and Qy calculated at the node 25 are calculated a plurality of times in unit time Tx intervals from the start of turning to the end of turning.

  In step S37, the average wear energy at the time of turning is calculated for each of the longitudinal land models 23a to 23e by the same calculation method as in step S34. The average wear energy of each longitudinal land model 23a-23e at the time of turning is stored in the physical quantity input unit 15E.

  Thus, the average wear energy of each rolling condition (free rolling, braking, driving and turning) is each node 25 of all elements F (i) of the tread small area 30 (each longitudinal land model 23 a to 23 e). Of the actual tire 2 which wears continuously in the tire circumferential direction because it is obtained based on the shear forces Px (i) and Py (i) and the slip amounts Qx (i) and Qy (i) calculated by It can be made to approximate to wear energy. For this reason, in the wear amount calculation step S6 described later, the actual wear amount of the tire 2 which wears continuously in the tire circumferential direction can be accurately predicted. Furthermore, since the friction coefficient between the actual tire 2 and the road surface is set between the tire model 21 and the road surface model 24, the average wear energy can be calculated with high accuracy.

  Next, in the simulation method of the present embodiment, the computer 1 performs the wear performance by condition of the tread small area 18 of the tire 2 for each rolling condition based on the average wear energy of the tread small area 30 of the tire model 21. Calculate (Conditional Wear Performance Calculation Step S4). In the condition-specific wear performance calculation step S4 of the present embodiment, the wear performance (wear of each vertical land portion 10a to 10e of the tire 2 for each rolling condition, based on the average wear energy of each longitudinal land model 23a to 23e Amount) is calculated.

  In the condition-specific wear performance calculation step S4, firstly, the average wear energy of the longitudinal land models 23a to 23e stored in the physical quantity input unit 15E is read into the working memory 13C for each rolling condition. Furthermore, in the condition-specific wear performance calculation step S4, the condition-specific wear performance calculation unit 16G for calculating the amount of wear of each longitudinal land portion 10a to 10e is read into the work memory 13C. Then, the condition-specific wear performance calculation unit 16G is executed by the calculation unit 13A. FIG. 10 is a flowchart showing an example of the processing procedure of the condition-specific wear performance calculation step S4.

  In the condition-specific wear performance calculation step S4 of this embodiment, first, the wear energy and the amount of wear of the rubber material of the tread small area 18 of the actual tire 2 (shown in FIGS. 2 and 3) are obtained (step S41) . In step S61 of the present embodiment, the wear energy and the amount of wear of the rubber material of each longitudinal portion 10a to 10e are acquired.

  In step S41, first, rubber pieces (not shown) cut from the respective longitudinal land portions 10a to 10e of the tire 2 shown in FIG. 2 are obtained. The wear energy relative to the amount of wear of the rubber material of each longitudinal land portion 10a to 10e can be determined by, for example, abrading these rubber pieces by means of an indoor wear tester (Runbone wear tester or the like).

  Next, in the condition-specific wear performance calculation step S4 of the present embodiment, a wear index indicating the relationship between the amount of wear of the rubber material and the wear energy of the rubber material is obtained (step S42). In step S42, the wear amount La of the rubber material is divided by the wear energy Ea of the rubber material for the tread small regions 18 (the longitudinal land portions 10a to 10e). Thereby, the wear index Ri of the rubber material of the tread small area 18 (each longitudinal portion 10a to 10e) can be obtained. FIG. 11 is a graph showing an example of the wear index Ri of the present embodiment. In such a wear index Ri, the wear amount La of the rubber material linearly changes (for example, increases) due to a change (for example, increase) of the wear energy Ea of the rubber material.

  Next, the condition-specific wear performance calculation step S4 of this embodiment is based on the wear index Ri of the rubber material and the average wear energy of each rolling condition, and the tread small area 18 (longitudinal portions 10a to 10e). The condition-specific wear performance is calculated (step S43). In step S63 of the present embodiment, the wear index Ri of the rubber material and the average wear energy are multiplied for each of the longitudinal parts 10a to 10e. The multiplication of the wear index Ri of the rubber material and the average wear energy is performed for each rolling condition (free rolling, braking, driving and turning). Thereby, the wear performance by condition (the amount of wear in the present embodiment) of each longitudinal land portion 10a to 10e is calculated for each rolling condition. The wear performance by conditions is stored in the physical quantity input unit 15E.

  Next, in the simulation method of the present embodiment, the computer 1 acquires the occurrence frequency of each rolling condition for the travel history of the vehicle provided in advance (occurrence frequency calculation step S5). The occurrence frequency of the present embodiment includes the occurrence frequency Ca of free rolling, the occurrence frequency Cb of braking, the occurrence frequency Cc of driving, and the occurrence frequency Cd of turning. Further, each occurrence frequency Ca to Cd is shown as a percentage where the total of occurrence frequency Ca of free rolling, occurrence frequency Cb of braking, occurrence frequency Cc of driving and occurrence frequency Cd of turning is 100%. In addition, each generation frequency Ca-Cd may be displayed by methods other than a percentage. FIG. 12 is a flow chart showing an example of the processing procedure of the occurrence frequency calculation step S5 of the present embodiment.

  In the occurrence frequency calculation step S5 of the present embodiment, first, the tire 2 (shown in FIG. 2) is caused to travel, and the actual wear performance of the tread small area 18 is acquired (step S51). In step S51 of the present embodiment, the actual amount of wear is acquired in each of the longitudinal parts 10a to 10e. Further, the actual wear amount of each longitudinal land portion 10a to 10e is obtained by the actual wear amount of each circumferential groove 9a to 9d and the tread ground contact end 2t (one tread ground contact end 2ta and the other tread ground contact end 2tb) Be done.

  In step S51, first, the tire 2 is mounted on an actual vehicle, and traveled along a route including, for example, a highway, a mountain road, and a general road. Then, after running of the tire 2, the actual amount of wear of each of the circumferential grooves 9a to 9d and the tread contact ends 2ta and 2tb is measured.

  The method of measuring the actual amount of wear of each of the circumferential grooves 9a to 9d can be adopted as appropriate. In this embodiment, first, the groove depth at the time of a new article and the groove depth after traveling are measured at three locations in the tire circumferential direction of each of the circumferential grooves 9a to 9d. Then, by averaging the difference between the new groove depth and the groove depth after traveling at three locations, the actual amount of wear of each of the circumferential grooves 9a to 9d can be obtained. FIG. 13 is a graph showing the actual amount of wear of each of the circumferential grooves 9a to 9d. The actual wear amount of each tread ground contact end 2ta, 2tb is also measured by the same measurement method as each of the circumferential grooves 9a to 9d. The actual wear amount of each of the circumferential grooves 9a to 9d and the actual wear amount of each of the tread ground contact ends 2ta and 2tb are stored in the physical quantity input unit 15E.

  Next, in the occurrence frequency calculation step S5 of the present embodiment, each rolling is performed by multiple regression analysis based on the actual wear performance of the tread small area 18 of the tire 2 and the average wear energy of the tread small area 30 of the tire model 21. Condition occurrence frequencies Ca to Cd are calculated (step S52). In step S52 of the present embodiment, the actual wear amount of each longitudinal land portion 10a to 10e (each circumferential groove 9a to 9d and each tread ground contact end 2ta, 2tb) and the average wear energy of each longitudinal land portion model 23a to 23e And multiple regression analysis is performed.

  In step S52, as shown in FIG. 1, the actual wear amounts of the circumferential grooves 9a to 9d stored in the physical quantity input unit 15E, the actual wear amounts of the tread ground contact ends 2ta and 2tb, and the longitudinal lands The average wear energy (including rolling conditions of free rolling, braking, driving, and turning) of the part models 23a to 23e is read into the work memory 13C. Furthermore, in step S52, the occurrence frequency calculation unit 16F that acquires the occurrence frequency of the rolling condition of the tire 2 is read into the work memory 13C. Then, the occurrence frequency calculation unit 16F is executed by the calculation unit 13A.

  In step S52, firstly, based on the average wear energy of each longitudinal land model 23a-23e, the average wear energy of each circumferential groove model 22a-22d and the average wear energy of each tread grounding end 21ta, 21tb are calculated. Be done. In the mean wear energy calculation step S3, only the mean wear energy of the longitudinal land models 23a to 23e is obtained, the mean wear energy of each circumferential groove model 22a to 22d and each tread ground end 21ta, 21tb is new. Required.

  In the present embodiment, as shown in FIG. 6, the average wear energy of the pair of longitudinal land portion models 23 a to 23 e disposed on both sides in the tire axial direction of each circumferential groove model 22 a to 22 d is a rolling condition. It is averaged every (free rolling, braking, driving and turning). Thus, the average wear energy of each circumferential groove model 22a to 22d is calculated for each rolling condition (free rolling, braking, driving, and turning).

For example, the average wear energy of the first center circumferential groove model 22a is the average wear energy of the center longitudinal land model 23a and the average wear energy of the first middle longitudinal land model 23b under the rolling conditions (free rolling , Braking, driving, and turning). FIG. 14 is a graph showing the average wear energy of each of the circumferential groove models 22a to 22d and the tread ground contact ends 2t, 2t for each rolling condition (free rolling, braking, driving, and turning). In FIG. 14, the average wear energy of the first center circumferential groove model 22a is, for example, as follows.
Average wear energy during free rolling of the first center circumferential groove model: 65 (J / m ² )
Average wear energy at braking of the first center circumferential groove model: 135 (J / m ² )
Average wear energy when driving the first center circumferential groove model: 140 (J / m ² )
Average wear energy when turning in the first center circumferential groove model: 290 (J / m ² )

  At each tread ground contact end 21 ta, 21 tb, a longitudinal land model (a first shoulder longitudinal land model 23 d or a second shoulder longitudinal land model 23 e) is disposed only on one side in the tire axial direction. For this reason, as the average wear energy of each tread ground contact end 21 ta, 21 tb, the average wear energy of the longitudinal land model adjacent to one side in the tire axial direction of the tread ground contact end 21 ta, 21 tb is set as it is.

For example, as shown in FIG. 6, as the average wear energy of one tread ground contact end 21 ta, the first shoulder land portion model 23 d is disposed only on the other side Sb in the tire axial direction. Therefore, the average wear energy (free rolling, braking, driving, and turning) of the first shoulder longitudinal land model 23d is set as the average wear energy of one tread ground contact end 21ta. In FIG. 14, the average wear energy of one tread ground contact end 21t is, for example, as follows.
Average wear energy during free rolling of one tread contact edge: 80 (J / m ² )
Average wear energy during braking on one tread contact end: 170 (J / m ² )
Average wear energy when driving one tread ground end: 80 (J / m ² )
Average wear energy at turning of one tread contact end: 300 (J / m ² )

  Next, in step S52 of the present embodiment, the average wear energy of each of the circumferential groove models 22a to 22d weighted by the occurrence frequency Ca to Cd of each rolling condition and each tread ground weighted on the occurrence frequency Ca to Cd The multiple regression analysis is performed based on the average wear energy of the ends 21 ta and 21 tb, the actual wear amounts of the circumferential grooves 9 a to 9 d, and the actual wear amounts of the tread contact ends 2 ta and 2 tb.

The average wear energy E1 of the first center circumferential groove model 22a weighted by the occurrence frequency Ca to Cd of each rolling condition can be expressed by the following equation (1).
E1 = Ca × E1a + Cb × E1b + Cc × E1c + Cd × E1d (1)
Here, each variable is as follows.
E1a: Average wear energy at free rolling of the first center circumferential groove model E1b: Average wear energy at braking of the first center circumferential groove model E1 c: Average wear energy at the time of driving the first center circumferential groove model E1d: Average wear energy when turning in the first center circumferential groove model

The average wear energy E2 of the second center circumferential groove model 22b weighted by the occurrence frequency Ca to Cd of each rolling condition can be expressed by the following equation (2).
E2 = Ca × E2a + Cb × E2b + Cc × E2c + Cd × E2d (2)
Here, each variable is as follows.
E2a: Average wear energy at free rolling of the second center circumferential groove model E2b: Average wear energy at braking of the second center circumferential groove model E2c: Average wear energy at the time of driving the second center circumferential groove model E2d: Average wear energy at turning of second center circumferential groove model

The average wear energy E3 of the first shoulder circumferential groove model 22c weighted by the occurrence frequency Ca to Cd of each rolling condition can be expressed by the following equation (3).
E3 = Ca × E3a + Cb × E3b + Cc × E3c + Cd × E3d (3)
Here, each variable is as follows.
E3a: Average wear energy at free rolling of the first shoulder circumferential groove model E3b: Average wear energy at braking of the first shoulder circumferential groove model E3c: Average wear energy at the driving of the first shoulder circumferential groove model E3d: Average wear energy when turning in the first shoulder circumferential groove model

The average wear energy E4 of the second shoulder circumferential direction groove model 22d weighted by the occurrence frequency Ca to Cd of each rolling condition can be expressed by the following equation (4).
E4 = Ca × E4a + Cb × E4b + Cc × E4c + Cd × E4d (4)
Here, each variable is as follows.
E4a: Average wear energy at free rolling of the second shoulder circumferential groove model E4b: Average wear energy at braking of the second shoulder circumferential groove model E4c: Average wear energy at the time of driving the second shoulder circumferential groove model E4d: Average wear energy when turning in the second shoulder circumferential groove model

The average wear energy E5 of one tread ground contact end 21ta weighted by the occurrence frequency Ca to Cd of each rolling condition can be expressed by the following equation (5).
E5 = Ca × E5a + Cb × E5b + Cc × E5c + Cd × E5d (5)
Here, each variable is as follows.
E5a: Average wear energy when free rolling on one tread ground end E5b: Average wear energy when braking on one tread ground end E5c: Average wear energy when driving one tread ground end E5d: One tread ground Average wear energy at end turning

The total wear energy E6 of the other tread ground contact end 21tb weighted by the occurrence frequency Ca to Cd of each rolling condition can be expressed by the following equation (6).
E6 = Ca × E6a + Cb × E6b + Cc × E6c + Cd × E6d (6)
Here, each variable is as follows.
E6a: Average wear energy at free rolling of the other tread ground end E6b: Average wear energy at braking of the other tread ground end E6c: Average wear energy at the time of driving the other tread ground end E6d: Other tread ground Average wear energy at end turning

  In the present embodiment, the average wear energy E1 to E4 of each circumferential groove model 22a to 22d weighted by the occurrence frequency Ca to Cd of each rolling condition, and each tread ground end weighted on the occurrence frequency Ca to Cd 21t 1 average wear energy E5 and E6 are subjected to multiple regression analysis so as to match the actual wear amount of each circumferential groove 9a to 9d and the actual wear amount of each tread ground contact end 2t. Thus, the occurrence frequencies Ca to Cd of the rolling conditions can be specified. Such multiple regression analysis can be easily calculated, for example, by using StatWorks manufactured by Jikken. The occurrence frequency of such rolling conditions is stored in the physical quantity input unit 15E.

  Next, in the simulation method of the present embodiment, the computer 1 calculates the predicted wear performance of the small tread area 18 when the tire 2 travels with the travel history (step S6). In step S6 of the present embodiment, in the small tread area 18 of the tire 2, the wear performance by conditions (wear amount in the present embodiment) of each rolling condition is weighted by the occurrence frequency Ca to Cd of each rolling condition By this, the predicted wear performance considering the travel history is calculated.

  In step S5, as shown in FIG. 1, the wear performance by condition of each rolling condition (wear amount in this embodiment) stored in the physical quantity input unit 15E, and the occurrence frequency Ca of each rolling condition .About.Cd are read into the working memory 13C. Furthermore, in step S5, the wear performance calculation unit 16H for calculating the predicted wear performance is read into the work memory 13C. Then, the wear performance calculation unit 16H is executed by the calculation unit 13A.

  In step S6 of the present embodiment, the wear performance by conditions (wear amount in the present embodiment) of each rolling condition is weighted by the occurrence frequency Ca to Cd of each rolling condition for each longitudinal land portion 10a to 10e. Ru. Thus, predicted wear performance (wear amount) can be calculated for each of the longitudinal parts 10a to 10e. Since such predicted wear performance is calculated based on the occurrence frequency Ca to Cd of each rolling condition acquired from the consideration of the travel history of the tire 2, the predicted wear performance (wear amount) It can be made to approximate accurately according to the amount of wear. The predicted wear performance of each longitudinal portion 10a to 10e is stored in the physical quantity input unit 15E.

  The condition-specific wear performance (in the present embodiment, the amount of wear) is based on the average wear energy calculated for each node 25 of all the elements F (i) of each longitudinal land model 23a-23e of the tire model 21. It is calculated. Therefore, in the simulation method of the present embodiment, the actual amount of wear of the tire 2 is predicted compared to the conventional method in which the amount of wear is predicted based on the wear energy at an arbitrary position of the tread portion 21a, for example. Wear performance (wear amount) can be accurately approximated.

  Next, in the simulation method of the present embodiment, the computer 1 determines whether the predicted wear performance of the tread small areas 18 (the longitudinal land portions 10a to 10e) of the tire 2 is within the allowable range (step S7). ). In step S7, when it is determined that the predicted wear performance of the tread small area 18 (each longitudinal land portion 10a to 10e) is within the allowable range ("Y" in step S7), the tire model 21 is used to 2 are manufactured (step S8). On the other hand, when it is judged that the predicted wear performance of the tread small area 18 (each longitudinal land portion 10a to 10e) is out of the allowable range ("N" in step S7), the design factor of the tire 2 is changed ( Step S9), steps S1 to S7 are performed again. Thus, in the simulation method of the present embodiment, the tire 2 with good wear resistance performance can be designed with certainty.

  In the occurrence frequency calculation step S5 of the present embodiment, the occurrence frequency Ca to Cd of each rolling condition is obtained based on the actual wear amount of one tire 2, but the invention is limited thereto. Do not mean. For example, the occurrence frequencies Ca to Cd of the rolling conditions may be acquired based on the actual wear amounts of the plurality of tires 2.

  In such a case, first, for each tire 2, multiple regression based on the average wear energy E1 to E6 (shown in the above formulas (1) to (6)) weighted by the occurrence frequency Ca to Cd and the actual wear amount By performing the analysis, the occurrence frequencies Ca to Cd of each tire are identified. And generation frequency Ca-Cd of each tire 2 is averaged, and one generation frequency Ca-Cd is specified.

  In such occurrence frequency calculation step S5, the occurrence frequencies Ca to Cd are specified based on the travel history (actual wear amount) of the plurality of tires 2, and therefore, it is estimated that the deviation of the travel history of each tire 2 is eliminated. The amount of wear can be determined. For example, in the destination where the tire 2 is used, the occurrence frequencies Ca to Cd can be identified with high accuracy, so the actual amount of wear and the estimated amount of wear of the tire at the destination can be accurately approximated.

  In the occurrence frequency calculation step S5 of the previous embodiments, the occurrence frequencies Ca to Cd of the rolling conditions are calculated based on the actual wear amount of the tread small regions 18 (the longitudinal land portions 10a to 10e) of the tire 2. Although the thing was illustrated, it is not limited to this. For example, the occurrence frequencies Ca to Cd of the rolling conditions may be determined based on the occurrence frequency of acceleration acquired by causing the tire 2 to travel. FIG. 15 is a flow chart showing an example of the processing procedure of the occurrence frequency calculation step S5 according to the other embodiment of the present invention.

  In the occurrence frequency calculation step S5 of this embodiment, first, the tire 2 is made to travel, and the occurrence frequency of the left and right acceleration (left and right G) and the front and back acceleration (front and back G) is acquired (step S61). In step S61, the tire 2 is attached to an actual vehicle, and a route including, for example, a highway, a mountain road, and a general road is made to travel. Then, the occurrence frequency of the left and right accelerations and the front and back accelerations is acquired in all the paths. The frequency of occurrence of such acceleration can be measured by an acceleration sensor (not shown) attached to the vehicle. FIG. 16 is a graph showing the frequency of occurrence of left and right acceleration. FIG. 17 is a graph showing the frequency of occurrence of acceleration before and after. The frequency of occurrence of such left and right acceleration and front and back acceleration is stored in the physical quantity input unit 15E.

  Next, in the occurrence frequency calculation step S5 of this embodiment, the occurrence frequencies Ca to Cd of the rolling conditions are acquired based on the occurrence frequency of the left and right acceleration and the front and back acceleration (step S62). In step S62, first, left and right accelerations are identified as turning that are greater than or equal to a predetermined acceleration, and those less than the predetermined acceleration are identified as going straight (free rolling, braking, or driving) There is. Furthermore, accelerations in front and back are specified as braking or driving that is equal to or higher than a predetermined acceleration, and those smaller than the predetermined acceleration are specified as free rolling or turning. Then, the occurrence frequencies Ca to Cd (for example, percentages) of the rolling conditions are specified based on the left and right acceleration and the occurrence frequency of the front and back acceleration.

  As described above, in the occurrence frequency calculation step S5 of this embodiment, the actual wear amount of the tread small regions 18 (the longitudinal land portions 10a to 10e) and the tread small regions 30 of the tire model 21 (the previous embodiment) Since the occurrence frequency Ca to Cd of each rolling condition can be obtained without performing the multiple regression analysis based on the average wear energy of each longitudinal land model 23a to 23e), the calculation time can be shortened.

The left and right accelerations serving as the determination criteria for turning and the front and rear accelerations serving as the determination criteria for braking or driving may be appropriately determined based on the characteristics of the vehicle and the like. In the present embodiment, it is determined based on 0.1G. In addition, the generation frequency of each rolling condition specified by this embodiment is as follows.
Free rolling occurrence frequency Ca: 48%
Frequency of occurrence of braking Cb: 12%
Drive frequency Cc: 12%
Turning frequency Cd: 28%

  In the wear amount calculation step S6 of the previous embodiments, as shown in FIG. 14, the wear amount La of the rubber material changes linearly (for example, increase) due to the change (for example, increase) of the wear energy Ea of the rubber material. Although the aspect by which the wear index Ri of the rubber material to be obtained is acquired is illustrated, it is not necessarily limited to this.

  Heretofore, it was thought that the rubber material would be worn if even a little wear energy Ea was generated. However, as a result of extensive research, the inventors have found that the wear of the rubber material starts after exceeding a certain wear energy Ea. Based on such findings, it is desirable that a wear index Ri in which the wear amount La of the rubber material changes non-linearly (for example, increase) is obtained by a change (for example, increase) of the wear energy Ea of the rubber material. FIG. 18 is a graph showing an example of the wear index Ri according to another embodiment of the present invention.

  In the wear index Ri of this embodiment, when the wear amount La of the rubber material is zero, the section Sn of the wear energy Ea is included. The wear index Ri indicates that the rubber material does not wear at a wear energy Ea less than or equal to the section Sn. By using such a wear index Ri, the predicted wear amount of the tread small area 18 (the longitudinal land portions 10a to 10e) can be determined with high accuracy. The wear index Ri of the rubber material may be determined for each longitudinal portion 10a to 10e.

  In order to obtain the non-linear wear index Ri, first, the wear energy at which the wear of the rubber material starts is obtained in advance. Then, the wear amount La of the rubber material, the wear energy Ea of the rubber material, and the section Sn can be determined by being plotted on a graph.

  The non-linear wear index Ri has a segment Sn if the wear amount La of the rubber material changes non-linearly (for example, increases) due to a change (for example, increase) of the wear energy Ea of the rubber material. Also, it does not have to have the segment Sn. For example, the increase in the wear energy Ea of the rubber material may be represented by a curve in which the wear amount La of the rubber material gradually increases. Such non-linear wear index Ri can be approximated to the wear of an actual rubber material. Note that such non-linear wear index Ri can be easily obtained by plotting wear amounts La corresponding to a plurality of wear energy Ea on a graph.

Such non-linear wear index Ri is the actual wear amount of the tread small area 18 of the tire 2 and the average wear energy of the tread small area 30 of the tire model 21 in step S52 of the occurrence frequency calculating step S5 shown in FIG. It may be used for multiple regression analysis based on. In this embodiment, in place of the above formulas (1) to (6), the following formulas (1) ′ to (6) ′ obtained by multiplying the above formulas (1) to (6) by the non-linear wear index Ri are used. .
H1 = Ca × E1a × Ri + Cb × E1b × Ri + Cc × E1c × Ri + Cd × E1d × Ri (1) ′
H2 = Ca * E2a * Ri + Cb * E2b * Ri + Cc * E2c * Ri + Cd * E2d * Ri (2) '
H3 = Ca * E3a * Ri + Cb * E3b * Ri + Cc * E3c * Ri + Cd * E3d * Ri (3) '
H4 = Ca × E4a × Ri + Cb × E4b × Ri + Cc × E4c × Ri + Cd × E4d × Ri (4) ′
H5 = Ca × E5a × Ri + Cb × E5b × Ri + Cc × E5c × Ri + Cd × E5d × Ri (5) ′
H6 = Ca × E6a × Ri + Cb × E6b × Ri + Cc × E6c × Ri + Cd × E6d × Ri (6) ′

Formula (1) 'to (6)', each circumferential groove models 22a to 22d, and each tread edge 21Ta, show the wear amount H1~H6 of 21TB. The multiple regression analysis is performed based on the following expressions (1) ′ to (6) ′, the actual wear amounts of the circumferential grooves 9a to 9d, and the actual wear amounts of the tread contact ends 2ta and 2tb. Thus, the occurrence frequencies Ca to Cd are identified.

Thus, each circumferential groove models 22a to 22d, and each tread edge 21Ta, the wear amount H1~H6 of 21TB, to be calculated on the basis of the non-linear abrasion index Ri, of each circumferential groove 9a~9d The occurrence frequency Ca to Cd of each rolling condition can be accurately calculated by performing multiple regression analysis with the actual wear amount and the actual wear amounts of the tread contact ends 2ta and 2tb. In this case, it is desirable to include a step (not shown) of calculating a non-linear wear index Ri prior to step S52.

  Although the aspect by which the some vertical land part 10 divided by the circumferential direction groove 9 is set as the tread small area 18 was illustrated in the embodiment until now, it is not necessarily limited to this. For example, in a slick tire not having a circumferential groove or a tire having a lug groove extending in the axial direction of the tire, the tread small area 18 may be defined by virtually dividing the tread portion 2a. In this case, it is desirable that, for example, 1 to 10 tread small regions 18 be set in the tire axial direction.

  The tire of such an embodiment does not have the circumferential grooves 9a to 9d as the tire 2 of the previous embodiments. Therefore, in the occurrence frequency calculation step S5, the occurrence frequency Ca of each rolling condition is determined by multiple regression analysis of the actual wear amount of each of the circumferential grooves 9a to 9d and the average wear energy of the circumferential groove models 22a to 22d. Cd can not be calculated.

  Therefore, in the occurrence frequency calculation step S5 of this embodiment, first, the average value of the actual wear amount of each tread small area 18 of the tire is obtained. Then, multiple regression analysis is performed based on the average value of the actual wear amount of each tread small area 18 and the average wear energy of each longitudinal land model 23a to 23e, so that the occurrence frequency Ca of each rolling condition is generated. ~ Cd can be calculated. The average value of the actual wear amount of each tread small area 18 is the actual wear amount of each tread small area 18 measured at a plurality of locations in the axial direction of the tire and in the circumferential direction of the tire. It can be determined by being averaged. Also, the actual amount of wear can be easily determined by reducing the thickness of the tread rubber of each tread small area 18 after the wear from the thickness of the tread rubber of each tread small area 18. In addition, for example, a laser dimension measurement device or the like is used to measure the thickness of the tread rubber of each tread small area 18.

  In the above embodiments, the average wear energy of the small tread area 30 is calculated based on the rolling conditions of free rolling, braking, driving and turning, but it is not limited thereto. is not. For example, if the average wear energy is calculated under at least two or more rolling conditions of free rolling, braking, driving, and turning, the predicted wear performance of the small tread region 30 can be calculated. For example, when the traveling history of the vehicle is braking and driving only for straight traveling, average wear energy at braking and driving, wear performance by condition, and occurrence frequency are calculated. Thereby, the predicted wear performance of the tread small area 30 can be calculated.

  As mentioned above, although the especially preferable embodiment of this invention was explained in full detail, this invention can be deform | transformed into a various aspect, and can be implemented, without being limited to embodiment of illustration.

  According to the processing procedure shown in FIG. 4, FIG. 8, FIG. 10 and FIG. 12, the amount of wear of the small tread area of the plurality of tires was predicted (Example 1 and Example 2). In Example 1 and Example 2, the average wear of each rolling condition (free rolling, braking, driving, and turning) based on the shear force and slip calculated at all nodes of each small tread area. Energy was calculated. In the tire model, the friction coefficient between the actual tire and the road surface was set in advance.

  Next, in Example 1 and Example 2, based on the amount of wear and wear energy measured by the Lambourn wear tester, a wear index indicating the relationship between the amount of wear of the rubber material and the wear energy of the rubber material is obtained It was done. Then, by multiplying the wear index by the average wear energy, the condition-specific wear performance (the amount of wear in the present embodiment) of each longitudinal land portion is calculated for each rolling condition.

  Next, in the occurrence frequency calculation step of Example 1 and Example 2, the actual wear amount of the tread small area (each longitudinal land portion) of the tire run under the following conditions is measured, and the actual wear amount and the tread small area A multiple regression analysis was performed based on the average wear energy of the longitudinal land model. The occurrence frequency of each rolling condition was determined by this multiple regression analysis. Then, by weighting the condition-specific wear performance by the occurrence frequency, the predicted wear performance (the amount of wear in the present embodiment) of each longitudinal land portion was obtained.

  In the wear index of Example 1, as shown in FIG. 13, the wear amount of the rubber material linearly changes (for example, increases) due to the change (for example, increase) of the wear energy of the rubber material. A graph showing the relationship between the predicted amount of wear and the actual amount of wear of Example 1 is shown in FIG. On the other hand, the wear index of the example, as shown in FIG. 18, is a non-linear increase in the amount of wear of the rubber material due to the increase of the wear energy of the rubber material. A graph showing the relationship between the predicted amount of wear and the actual amount of wear of Example 2 is shown in FIG.

For comparison, the wear energy of a plurality of tires was determined according to the method described in Patent Document 1 (Comparative Example). In the comparative example, a glass plate was used as a tread for rolling the tire. In addition, the wear energy of the tire of the comparative example was measured at an arbitrary position of the tread portion of the tire. And, based on the wear energy of the tire, the wear amount of each longitudinal land portion of the plurality of tires was predicted. The relationship between the predicted amount of wear and the actual amount of wear of the comparative example is shown in FIGS. 19 and 20, respectively. The common specifications are as follows.
Tire size: 215/60 R16
Rim size: 16 x 6.5
Occurrence frequency calculation process:
Vehicle's travel history (distance): 20000 km (main course straight ahead)
Vehicle: Domestic FF car with a displacement of 2500 cc Load: 3920 N
Internal pressure: 240 kPa

As a result of the test, the correlation coefficients of Example 1, Example 2 and Comparative Example were as follows. In Example 1 and Example 2, the correlation with the actual amount of wear of the tire was higher than that of the comparative example. Therefore, Example 1 and Example 2 were able to predict the wear amount of the tire more accurately than the Comparative Example.
Correlation coefficient of Example 1: 0.76
Correlation coefficient of Example 2: 0.80
Correlation coefficient of comparative example: 0.01

  Furthermore, Example 2 had a higher correlation with the actual amount of wear of the tire than Example 1. This is considered to be because the wear index Ri of Example 2 shows the relationship between the wear amount of the actual rubber material and the wear energy as compared with the wear index Ri of Example 1. Therefore, Example 2 was able to predict the wear amount of the tire more accurately than Example 1.

2 tires 10 longitudinal land portion 21 tire models 18, 30 longitudinal land portion model

Claims (8)

A method of using a computer to predict the wear performance of at least one tread small area continuous in the tire circumferential direction of a tread portion of a tire,
Inputting a tire model obtained by modeling the tire with a finite number of elements in the computer;
The computer causes the tire model to run under at least two or more rolling conditions of free rolling, braking, driving, and turning, and the tread small area is grounded in the tread small area of the tire model. The average wear energy of a unit time obtained by dividing the integrated value of the wear energy calculated for each of the finite number of elements from the entry to the contact end by the contact area of the small tread area is calculated to start rolling of the tire model. Calculating an average wear energy obtained by dividing the integrated value of the average wear energy of the unit time from the start of rolling to the end of rolling by the total time from the start of rolling to the end of rolling for each rolling condition;
The condition-specific wear performance calculating step in which the computer calculates the condition-specific wear performance of the small tread region of the tire for each rolling condition based on the average wear energy.
An occurrence frequency calculation step in which the computer acquires the occurrence frequency of the rolling conditions with respect to the traveling history of the vehicle provided in advance, and the computer determines the rolling conditions in the small tread area of the tire. A method of simulating a tire, comprising the steps of: calculating the predicted wear performance of the small tread area when the tire has traveled with the travel history by weighting the wear performance by condition according to the occurrence frequency .
The occurrence frequency calculation step is a step of running the tire to obtain actual wear performance of the tread small area, actual wear performance of the tread small area of the tire, and the tread small area of the tire model The tire simulation method according to claim 1, further comprising the step of calculating the occurrence frequency of each rolling condition by multiple regression analysis based on the average wear energy .
The occurrence frequency calculation step is a step of running the tire and acquiring the occurrence frequency of left and right acceleration and front and rear acceleration, and the rolling based on the occurrence frequency of the left and right acceleration and the front and rear acceleration. The tire simulation method according to claim 1, further comprising the step of acquiring the occurrence frequency of the condition. The condition-specific wear performance calculation step is a step of acquiring the wear amount and wear energy of the rubber material of the tread small area of the tire,
Obtaining a wear index indicating a relationship between an amount of wear of the rubber material and a wear energy of the rubber material in the small tread area; and a wear index of each rubber material and the average wear of the small tread area The tire simulation method according to any one of claims 1 to 3, further comprising the step of calculating the condition-specific wear performance of the small tread region for each of the rolling conditions based on energy. The tire simulation method according to claim 4, wherein the wear index shows a relationship in which a wear amount of the rubber material changes non-linearly due to a change in wear energy of the rubber material.
The tread portion is provided with at least one longitudinal land portion divided by circumferential grooves continuously extending in the tire circumferential direction,
The tire simulation method according to any one of claims 1 to 5, wherein the tread small area of the tire is set in the longitudinal land portion. The tire model has a longitudinal land model that models the longitudinal land,
The tire simulation method according to claim 6, wherein the tread small area of the tire model is set to the longitudinal land model. A tire simulation device having an arithmetic processing unit for predicting the wear performance of at least one tread small area continuous in the tire circumferential direction of a tread portion of a tire, comprising:
The arithmetic processing unit sets a tire model in which the tire is modeled by a finite number of elements, and a tire model setting unit,
The tire model is run under at least two or more rolling conditions of free rolling, braking, driving, and turning, and in the tread small area of the tire model, from the ground contact to the ground end of the tread small area The average wear energy of a unit time obtained by dividing the integrated value of the wear energy calculated for each of the finite number of elements of the above by the ground contact area of the tread small area is determined. An average wear energy calculating unit that calculates an average wear energy obtained by dividing the integrated value of the average wear energy of the unit time by the total time from the start of rolling to the end of rolling, for each rolling condition,
Condition-specific wear performance calculation unit that calculates condition-specific wear performance of the small tread region of the tire for each rolling condition based on the average wear energy,
Regarding the travel history of the vehicle provided in advance, the occurrence frequency calculation unit that acquires the occurrence frequency of each rolling condition, and the wear performance by condition under each rolling condition in the small tread area of the tire, An apparatus for simulating a tire, comprising a wear performance calculation unit that calculates a predicted wear performance of the small tread area when the tire travels with the travel history by weighting the occurrence frequency.