Method for evaluating tire friction energy and computer

Abstract

To provide a friction energy evaluation method and so on that is easy to objectively evaluate an actually measured wear life.SOLUTION: According to a tire friction energy evaluation method, first friction energy is obtained for each of a plurality of contact nodal points by analyzing a model tire by a finite element analysis method. A specific region, which is included in regions where a distance from a major groove of the tire is a prescribed value or less, is extracted, and an average second friction energy in the specific region is determined on teh basis of the first friction energy. A plurality of first friction energies at the plurality of contact nodal points are converted into a plurality of third friction energies at a plurality of second contact nodal points with small resolution power by interpolation. The second friction energy may be calculated by use of the third friction energy at the second contact nodal point included in the specific region.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for evaluating the frictional energy of a tire and a computer. [Background technology]

[0002] BACKGROUND ART It has been known that, by evaluating the frictional energy of a tire using a finite element analysis method, information regarding the frictional energy of a tire can be obtained without actually manufacturing a prototype tire (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-240540 Summary of the Invention [Problem to be solved by the invention]

[0004] The wear life of a tire may be evaluated numerically by measuring the amount of wear in the main grooves of the tire after the tire is mounted on a vehicle and driven over a predetermined course. Alternatively, a possible method for evaluating the wear life of a tire through simulation is to use finite element analysis to determine the friction energy on the tire surface and calculate the average value.

[0005] However, the inventors of the present application found that this method makes it impossible to objectively evaluate the wear life of an actually measured tire, which evaluates the wear life only based on the amount of wear in the main grooves, which is a localized area of ​​the tire, because the friction energy of the tire surface, which is a wide area, contributes to the evaluation.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method and computer for evaluating tire friction energy that facilitates objective evaluation of actual wear life. [Means for solving the problem]

[0007] The method for evaluating the frictional energy of a tire according to the present invention involves analyzing a model tire using finite element analysis to obtain a first frictional energy for each of a plurality of contact nodes, extracting a specific region included in an area that is a predetermined distance or less from the main groove of the tire, and calculating the average second frictional energy of the specific region based on the first frictional energy.

[0008] In addition, the computer according to the present invention includes an acquisition unit that acquires first friction energy for each of a plurality of contact nodes by analyzing a model tire using finite element analysis, and an average friction energy calculation unit that extracts a specific region included in an area that is a predetermined distance or less from the main groove of the tire, and calculates the average second friction energy of the specific region.

[0009] The main groove is a groove formed on the outer peripheral surface of the tread and having at least one of a straight portion, a curved portion, and a zigzag portion. The main groove may be defined as the deepest groove (a groove designed as the deepest groove). In this case, the tire may have multiple main grooves, and the multiple main grooves may have substantially the same maximum depth (the maximum depths differ by the value of the tolerance (manufacturing error)), and the depth of the main groove may be deeper than the depth of the non-main groove (meaning that the dimension is deeper than the value of the tolerance (manufacturing error)). Alternatively, the main groove may be defined as the groove designed as the groove with the largest maximum width. Alternatively, the tire may have multiple main grooves, and the multiple main grooves may divide the tread into multiple land regions. In other words, the main groove may be defined as a groove that divides the tread into multiple land regions. Alternatively, the main groove may be defined as a groove provided with an indicator. Here, the indicator is a portion for identifying tire wear, such as a raised rubber portion provided at the bottom of the tire groove. [Effects of the Invention]

[0010] The frictional energy evaluation method and computer of the present invention make it easy to objectively evaluate the actually measured wear life. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 illustrates a computer according to an embodiment of the present disclosure. [Figure 2] 1 is a flowchart illustrating an example of a processing procedure for a tire simulation according to the present disclosure. [Figure 3] FIG. 1 is a perspective view showing an example of a model tire for performing a simulation. [Figure 4] FIG. 2 is a cross-sectional view including the radial and width directions of a portion of a model tire having a tread pattern. [Figure 5A] This is a partial development of the tread pattern of the tire of Model A, in which the friction energy at each contact node is visualized by changing the dot density. [Figure 5B] 5B is a partial development view of a region after the plurality of contact nodes have been converted into a plurality of second contact nodes, the region corresponding to the region shown in FIG. 5A. FIG. [Figure 6A] FIG. 5B is a partial development view of tire B corresponding to FIG. 5A. [Figure 6B] FIG. 5C is a partial development view of tire B corresponding to FIG. 5B. [Figure 7] (a) is a graph showing the average value of frictional energy of actual measurements, (b) is a graph showing Eave based on extraction of specific regions of the present disclosure, and (c) is a graph showing the average value of frictional energy of a reference example in which specific regions are not extracted. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that, when multiple embodiments or variations are included below, it is anticipated from the beginning that new embodiments can be constructed by appropriately combining their characteristic features. In the following examples, the same components are designated by the same reference numerals in the drawings, and redundant explanations will be omitted. The drawings include schematic diagrams, and the dimensional ratios of the length, width, height, etc. of each component between different drawings do not necessarily match. Among the components described below, components not recited in the independent claims representing the highest concepts are optional components and not essential components.

[0013] 1 is a diagram showing a computer 1 according to an embodiment of the present disclosure. The computer 1 can be used as a simulator and includes a main body 1a, a keyboard 1b and a mouse 1c as input means, and a display device 1d as output means. The main body 1a has a control device including a control unit and a storage unit.

[0014] The control unit, i.e., the processor, includes, for example, a CPU (Central Processing Unit). The storage unit is composed of a hard disk drive (HDD), a semiconductor memory, etc., and the semiconductor memory is composed of a non-volatile memory such as a ROM (Read Only Memory) or a volatile memory such as a RAM (Random Access Memory). The storage unit may be composed of only one storage medium, or may be composed of multiple different storage media. The CPU, for example, reads and executes programs stored in the storage unit in advance. The non-volatile memory stores, for example, a control program and predetermined thresholds in advance. The volatile memory temporarily stores, for example, the read program and processing data. The storage unit stores a program for executing a tire simulation, which will be described later.

[0015] Fig. 2 is a flowchart showing an example of a processing procedure for a tire simulation according to the present disclosure. As shown in Fig. 2, in the simulation, first, in step S1, a model tire is analyzed using finite element analysis to obtain a first friction energy for each of a plurality of contact nodes. Fig. 3 is a perspective view showing an example of a tire model A used for the simulation. The tire model A (hereinafter referred to as tire A) is actually numerical data handled by a computer 1, but Fig. 3 visualizes this data as a perspective view.

[0016] As shown in Fig. 3, tire A partially has three or more tread patterns repeated in the circumferential direction, for example, only six tread patterns 11 partially in the circumferential direction. Fig. 4 is a cross-sectional view including the radial and width directions of a portion of model tire A having tread pattern 11. As shown in Fig. 4, model tire A to be analyzed is divided into a finite number of small elements 10a, 10b, 10c, etc. The tire to be analyzed may be an actual tire or a non-existent tire in the design stage, but in this embodiment, a case where an actual tire is used will be described.

[0017] Each of the elements 10a, 10b, 10c, etc. is defined so as to enable numerical analysis by the finite element method. Specifically, nodal coordinate values, shape, material properties (e.g., density, elastic modulus, loss tangent, or damping coefficient), etc. are defined for each of the elements 10a, 10b, 10c, etc. Each of the elements 10a, 10b, 10c, etc. is formed, for example, by triangular or quadrilateral membrane elements as two-dimensional planes, or by tetrahedral or hexahedral solid elements as three-dimensional elements. As described above, tire A has a tread pattern 11. The tread pattern 11 is divided into a finite number of elements, and the three-dimensional shape is incorporated into the model tire A.

[0018] The tread pattern 11 has a plurality of blocks defined by longitudinal grooves 9 and lateral grooves (not shown), and the blocks include, for example, crown blocks 11a, middle blocks 11b, and shoulder blocks 11c arranged in sequence from the tire equator toward the tread edge. Note that the specific shape and arrangement of the grooves are not limited.

[0019] The radially outer surface of each block constitutes the tread surface 12 that comes into contact with the road surface. The tread surface 12 of the model tire A is composed of a continuum of element surfaces that form a quadrilateral surrounded by four adjacent nodes, for example. The tread surface 12 is assumed to be in contact with a virtual road surface. The tread pattern 11 is a portion located radially outward from the groove bottom of the deepest longitudinal groove. FIG. 3 illustrates an example in which the portion between the tread ends Te, Te is modeled in a layered manner using small-thickness three-dimensional elements 13 that are substantially parallel to the tread surface 12 that comes into contact with the road surface, and the elements 13 are formed of hexahedral solid elements. The elements 13 are not limited to hexahedrons as long as they are layered, and various elements, such as pentahedrons, may be used.

[0020] Once the model tire A is divided into multiple elements, the necessary boundary conditions are set for the model tire A, and a wear simulation is performed based on these. The boundary conditions may include, for example, at least one of the following: a condition related to the rim on which tire A is mounted, a condition related to the air pressure to which tire A is inflated, a condition related to the load applied, and a condition related to the rolling speed.

[0021] The rim-related conditions are parameters required to reproduce the rim-mounted state of tire A, and specifically include the rim contact areas R, R where tire A comes into contact with the rim, the definition of the constraint that prevents this rim contact area R from displacing, the width RW between the rim contact areas R, R (usually equal to the rim width of the applicable rim), the virtual rotation axis CL of tire A, and the relative distance r between the rotation axis CL and the rim contact area R (always constant at the rim radius). Furthermore, as a condition related to air pressure, a uniformly distributed load w equivalent to the air pressure analyzed over the entire inner surface of tire A is defined. The value of the vertical load F that presses the rotation axis CL of tire A vertically downward is set as the applied load condition. The rolling speed-related conditions include the rotational speed and rolling time of tire A, as well as various friction coefficients between tire A and a virtual road surface (described below).

[0022] The model setting step of setting the model tire A and the setting of the boundary conditions are usually performed as appropriate using a computer 1 while taking into consideration the user's requests. In the wear simulation, tire A is brought into contact with a virtual road surface 15 based on the determined boundary conditions, and a rolling simulation is performed. Then, the wear characteristics of the model tire A are obtained from the simulation.

[0023] The virtual road surface 15 is a model of the road surface on which tire A runs, and is modeled, for example, using horizontally arranged planar elements. The wear simulation involves rolling tire A on the virtual road surface 15 based on boundary conditions, and calculating the forces and displacements occurring on the tread surface 12; more specifically, calculating the dynamic deformation state of the model tire A. This calculation can be performed using a computer 1 using, for example, general-purpose finite element analysis application software (such as the application software "LS-DYNA" manufactured by Livermore Software Technology Corporation (LSTC) in the United States) based on information, provided that the model tire A and boundary conditions can be set. In the wear simulation, additional conditions such as the slip angle of the model tire A and longitudinal G force may be added as necessary.

[0024] By performing a wear simulation, the wear characteristics of the model tire A can be obtained. The "wear characteristics" are parameters for evaluating the wear resistance performance of the tread pattern 11 of tire A, and include physical quantities such as the amount of slip of each element when in contact with the ground, ground contact pressure, friction energy, and "amount of slip × ground contact pressure." By obtaining the wear characteristics, it is possible to identify areas of the tread pattern 11 that are prone to wear and areas that are not prone to wear.

[0025] In this embodiment, friction energy is used as the "wear characteristic." Friction energy is a physical quantity calculated by summing up the product of the force acting on each element of the rolling tread surface 12 and the amount of slippage, calculated at minute time intervals from the time the element makes contact with the road surface until it leaves the surface. Friction energy correlates with wear of the tread rubber, and it can be concluded that areas with higher friction energy are more likely to wear out quickly.

[0026] In the tread pattern 11 of the model tire A, for at least all nodes appearing on the tread surface 12, the shear forces in two mutually perpendicular directions that are applied during contact with the ground and the amount of slip in the direction of action of each shear force are calculated, and these values ​​are multiplied together to calculate the friction energy. The calculated friction energy is stored in the memory unit of the computer 1.

[0027] FIG. 5A is a partial development of the tread pattern of tire A, in which the frictional energy at each contact node is visualized by changing the dot density. More specifically, FIG. 5A is a partial development showing the frictional energy distribution in the area where the six-pitch tread pattern that tire A has periodically and partially in the circumferential direction is present. Note that FIG. 5A indicates that the higher the dot density, the higher the frictional energy. As shown in FIG. 5A, it can be seen that in tire A, large frictional energy acts on the edge portion around the shoulder block 11c. The frictional energy distribution shown in FIG. 5A is the first frictional energy to be obtained in step S1 of FIG. 2.

[0028] Referring again to FIG. 2, in step S2 after step S1, a plurality of first friction energies at a plurality of contact nodes are converted into a plurality of third friction energies at a plurality of second contact nodes with a smaller resolution by an interpolation method. Specifically, the plurality of first friction energies at a plurality of contact nodes are converted into cell data by an interpolation method. The resolution of one cell data is, for example, 0.1 mm. 2 More than 0.3mm 2 Set to the following, for example, 0.2 mm 2 The contact nodes do not need to be evenly spaced, but the second contact nodes that define the cells are evenly spaced in the development.

[0029] In step S3 after step S2, a specific region is determined. Only the third friction energy of the second contact nodes located within the specific region is used to calculate the second friction energy. FIG. 5B is a partial development view after the multiple contact nodes are converted into multiple second contact nodes, and is a partial development view of the region portion corresponding to the region portion shown in FIG. 5A. The specific region TR is the region indicated by diagonal hatching in FIG. 5B. As shown in FIG. 5B, the specific region includes a main groove facing region 70 that faces the main grooves A, B, C, and D at a distance and extends along the main grooves A, B, C, and D.

[0030] <Conditions for determining specific areas> The specific region is determined so as to satisfy the following conditions (a) to (c). (a) The specific region is included in a range of ±10 mm in the width direction from the center position of each main groove in the width direction. In the example shown in FIG. 5B, there are four main grooves: main groove A, main groove B, main groove C, and main groove D. The center of main groove A in the width direction is located -51 mm from the center of the width direction in the developed view of FIG. 5B and shifted to one side in the width direction (the left side in FIG. 5B). The center of main groove B in the width direction is located -17 mm from the center of the width direction in the developed view of FIG. 5B and shifted to one side in the width direction. The center of main groove C in the width direction is located 17 mm from the center of the width direction in the developed view of FIG. 5B and shifted to the other side in the width direction (the right side in FIG. 5B). The center of main groove D in the width direction is located 51 mm from the center of the width direction in the developed view of FIG. 5B and shifted to the other side in the width direction. Therefore, under condition (a), when the widthwise center of the unfolded view in Figure 5B is taken as the widthwise origin, the specific area exists in the ranges of -61 mm to -41 mm, -27 mm to -7 mm, 7 mm to 27 mm, and 41 mm to 61 mm.

[0031] (b) The specified area is the area between 2mm and 4mm away from the edge of all grooves (including grooves other than the main grooves) except for sipes. Here, a sipe is defined as follows: The maximum groove width is 2mm The maximum opening area is 4mm 2 is.

[0032] (c) The specific area exists in only a portion of the circumferential direction of the model tire, and is in a one-pitch tread pattern area other than the two tread patterns located at both ends of the circumferential direction among multiple cyclically repeated tread patterns.

[0033] <Physical meaning of each condition> (The significance of setting the condition (a)) It is believed that the higher the level of friction energy, the worse the wear life. Here, friction energy analysis provides the distribution of friction energy across the tread surface, so it is conceivable to calculate the average value of this distribution and evaluate the wear life. However, in actual measurements, wear life is evaluated locally based on the average amount of wear near the main groove after driving a specified course in an actual vehicle test, and there is a problem that it is difficult to accurately evaluate it in a global evaluation. By satisfying condition (a), only the friction energy near the position where the groove depth is measured in the actual measurement is extracted, so the results of the wear life measurement in the actual measurement can be evaluated objectively and fairly.

[0034] (The significance of setting the condition (b)) The edges of the blocks are significantly worn away in actual measurements using an actual vehicle, so they are excluded from the evaluation points when measuring groove depth. Therefore, by averaging the friction energy in an area a certain distance from the edge, an evaluation corresponding to the measurement results can be performed. Furthermore, for sipes, which are minute grooves, the significant wear seen at the edges of the blocks is small. Therefore, even if these are included as evaluation points, the measurement results can be evaluated objectively and fairly.

[0035] (The significance of setting the condition (c)) First, as shown in Figure 2, by assuming that multiple periodically repeating tread patterns exist only in a portion of the circumferential direction of the model tire, the amount of calculation (computational cost) required to obtain the first friction energy for each of the multiple contact nodes in step S1 can be significantly reduced. In this context, for tread patterns that exist at both ends in the circumferential direction, there is a risk that a valid evaluation of the onset or takeoff of rolling motion cannot be performed because the tread pattern does not exist in the area adjacent to one side in the circumferential direction. By satisfying condition (c), the circumferential range of the model tire can be limited to a central one-pitch area, so that the pattern exists in the contact area from onset to takeoff during rolling motion, enabling an objective and valid evaluation of the wear life measurement results in actual measurements.

[0036] Referring again to FIG. 2, in step S4 after step S3, second contact nodes included in the specific region are identified, and the third friction energy of each identified second contact node is obtained. In the following step S5, the average value Eave of the multiple third friction energies acquired in step S4 is calculated. This average value Eave of the third friction energies becomes the second friction energy. The average value Eave can be calculated by dividing the sum of the multiple third friction energies corresponding to the multiple second contact nodes included in the specific region by the number of multiple second contact nodes.

[0037] In step S6 after step S5, the average value Eave calculated in step S5 is converted into a wear index that can be used as a measure of the amount of wear. The average value Eave of the third friction energy calculated by averaging after extracting the data of the third friction energy is converted into an index that serves as a measure of the ease of wear of the tread rubber relative to the friction energy, thereby making it possible to further improve prediction accuracy.

[0038] Specifically, the average value Eave of the third friction energy is converted into an index that serves as a measure of ease of abrasion using the following formula (1), that is, a theoretical formula for calculating the wear volume in abrasive wear. V = k((μWS) / (Hσε)) (1) In equation (1), V is the wear volume (mass), k is a constant, μ is the friction coefficient, W is the load (surface pressure), S is the sliding distance, H is the hardness, σ is the breaking strength (tensile strength), and ε is the breaking strain (elongation).

[0039] The above formula (1) can be rewritten as the following formula (2) using Eave. V=k((μWS) / (Hσε))=k·Eave / (Hσε)···(2) Therefore, Eave / (Hσε) can be used as a wear index (wear scale), and by using this wear index, the ease with which a tire can be evaluated more objectively. When step S6 is completed, the tire simulation is completed. Note that step S6 may be omitted, and the wear life of the model tire may be predicted using the Eave calculated in step S5.

[0040] <Comparison between simulation and actual measurements> The inventors of the present application prepared tire A described using FIGS. 5A and 5B and a different model B tire (hereinafter simply referred to as tire B). FIG. 6A is a partial developed view of tire B corresponding to FIG. 5A, and FIG. 6B is a partial developed view of tire B corresponding to FIG. 5B. Then, a simulation of calculating frictional energy was performed for each of tire A and tire B, and the simulation results were compared with the actual measured values. Specifically, for each of tire A and tire B, the average value of frictional energy of a reference example in which a specific region was not extracted and the above-mentioned Eave based on extraction of a specific region of the present disclosure were calculated. Then, these values ​​were compared with the actual measured values ​​of tire A and tire B.

[0041] Figure 7 is a graph showing the results. In detail, Figure 7(a) is a graph showing the average value of friction energy of the actually measured values, Figure 7(b) is a graph showing Eave based on the extraction of the specific region of the present disclosure, and Figure 7(c) is a graph showing the average value of friction energy of a reference example in which the specific region is not extracted. As shown in Figure 7(a), tire B has a larger average value of friction energy than tire A, and the tread rubber is more easily worn away.

[0042] In response to this reality, the average friction energy values ​​for the reference example in which no specific region is extracted, as shown in Figure 7(c), are similar for Tire A and Tire B. Therefore, it can be seen that if the average friction energy values ​​for the reference example in which no specific region is extracted are used, it is not possible to objectively evaluate the actual measured values ​​for Tire A and Tire B.

[0043] In contrast, according to the Eave based on extraction of the specific region of the present disclosure shown in Figure 7(c), the value for tire B is greater than the value for tire A. Therefore, by using the Eave based on extraction of the specific region of the present disclosure, it is possible to more accurately and objectively evaluate the reality that tire B has a greater average friction energy than tire A and its tread rubber is more susceptible to wear.

[0044] <Configuration of the tire disclosed herein and its effects> [Essential Configurations of the Tire of the Present Disclosure and Their Functions and Effects] The disclosed method for evaluating the frictional energy of a tire involves analyzing a model tire using finite element analysis to obtain a first frictional energy for each of multiple contact nodes, extracting a specific area included in an area that is a predetermined distance or less from the main groove of the tire, and calculating the average second frictional energy of that specific area based on the first frictional energy.

[0045] The computer 1 of the present disclosure also includes an acquisition unit that acquires the first friction energy for each of a plurality of contact nodes by analyzing the model tire using finite element analysis, and an average friction energy calculation unit that extracts a specific region included in an area that is a predetermined distance or less from the main groove of the tire, and calculates the average second friction energy of the specific region based on the first friction energy.

[0046] According to the present disclosure, only the region around the tire's main grooves is extracted from the friction energy of the tire surface calculated using finite element analysis, and the wear life is evaluated using the average value of the friction energy of the extracted region. Therefore, it is possible to calculate the friction energy corresponding to the actually measured wear life, which evaluates the wear life based only on the amount of wear of the main grooves, and to evaluate the actually measured wear life more objectively and accurately.

[0047] [Configurations and Effects Preferable to be Adopted in Tires of the Present Disclosure] A plurality of first friction energies at a plurality of contact nodes may be converted into a plurality of third friction energies at a plurality of second contact nodes with a smaller resolution by interpolation, and the second friction energies may be calculated using the third friction energies of the second contact nodes included in the specific region.

[0048] According to this configuration, multiple contact nodes that are not necessarily evenly spaced in a two-dimensional plane can be converted into multiple second contact nodes that are evenly spaced in a two-dimensional plane and have high resolution, thereby enabling accurate and easy calculation of the average second frictional energy in a specific region.

[0049] The specific region may also include a main groove facing region 70 that faces the main grooves A, B, C, and D at a distance and extends along the main grooves A, B, C, and D.

[0050] According to this configuration, the wear life can be evaluated with higher accuracy than the actually measured wear life that is evaluated only based on the amount of wear of the main groove.

[0051] The tire model may have a groove pattern with multiple pitches, in which multiple identical groove patterns are repeated in the circumferential direction only in a portion of the circumferential direction. The second friction energy may be calculated using only the first friction energy of the contact nodes included in one or more pitches other than the two end pitches among the multiple consecutive pitches.

[0052] This configuration significantly reduces the amount of calculation (computational cost) required to obtain the first friction energy for each of the multiple contact nodes. Also, since the circumferential range of the model tire can be limited to the central one-pitch region, a pattern can be present in the contact area from the leading edge to the trailing edge during rolling, allowing for an objective and fair evaluation of the wear life measurement results in actual measurements.

[0053] In addition, the second friction energy and Recipe A wear evaluation formula for evaluating wear in a specific region may be calculated based on a theoretical formula relating to wear of the block.

[0054] According to this configuration, the wear life of the actually measured sample can be evaluated with higher accuracy using a measure of wear rather than friction energy.

[0055] <Modification> The present disclosure is not limited to the above-described embodiment and its modifications. Various improvements and modifications are possible within the scope of the claims and their equivalents. For example, the present disclosure does not require that multiple first friction energies at multiple contact nodes be converted into multiple third friction energies at multiple second contact nodes with lower resolution by interpolation. Furthermore, the model tire may have a tread pattern that is periodically repeated around the entire circumference. Furthermore, the wear life may be evaluated based on the average second friction energy of a specific region without calculating a wear evaluation formula.

[0056] Furthermore, the various numerical values ​​used in the conditions (a) and (b) above are merely examples, and these various numerical values ​​may be replaced with other numerical values. Furthermore, the definition of a sipe does not have to be that shown in (b) above, and the various numerical values ​​used in the definition of a sipe may be replaced with other numerical values. Furthermore, although the case where a sipe is the subject of evaluation positions has been described, a sipe may not be the subject of evaluation positions, and may be treated equivalently to other grooves such as main grooves. [Explanation of symbols]

[0057] 1 computer, 1a main body, 1b keyboard, 1c mouse, 1d display device, 9 longitudinal groove, 10a, 10b, 10c elements, 11 tread pattern, 11a crown block, 11b middle block, 11c shoulder block, 12 tread surface, 13 element, 15 virtual road surface, 70 main groove opposing area, A, B, C, D main groove, A, B tire, CL rotation axis, F vertical load, R rim contact area, RW width, TR specific area, Te tread edge, r relative distance, w uniformly distributed load.

Claims

1. A first friction energy is obtained for each of a plurality of contact nodes by analyzing the model tire using a finite element analysis method; A specific region is extracted from the model tire, the specific region being present in a region of a one-pitch tread pattern other than the two tread patterns present at both ends in the circumferential direction among a plurality of tread patterns that are present only in a portion of the circumferential direction and that are periodically repeated, the specific region being included in a region within a range of ±10 mm in the width direction from the center position of each main groove in the width direction of the tire, and the specific region being included in a region that is 2 mm or more and 4 mm or less away from the edges of all grooves excluding sipes, a second friction energy of the specific region being determined based on the first friction energy;

2. converting the plurality of first friction energies at the plurality of contact nodes into a plurality of third friction energies at a plurality of second contact nodes having a smaller resolution by interpolation; The method for evaluating frictional energy of a tire according to claim 1 , wherein the second frictional energy is calculated using the third frictional energy of the second contact node included in the specific region.

3. The method for evaluating frictional energy of a tire according to claim 1 or 2, wherein the specific region includes a main groove facing region that faces the main groove at a distance and extends along the main groove.

4. The tire of the model has a plurality of identical pattern grooves at a plurality of pitches repeated in the circumferential direction only in a part of the circumferential direction, 4. The method for evaluating frictional energy of a tire according to claim 1, wherein the second frictional energy is calculated using only the first frictional energy of the contact nodes included in one or more of the plurality of consecutive pitches other than the pitches at both ends.

5. 5. The method for evaluating frictional energy of a tire according to claim 1, further comprising: calculating a wear evaluation formula for evaluating wear in the specific region based on the second frictional energy and a theoretical formula related to abrasive wear.

6. an acquisition unit that acquires first friction energy for each of a plurality of contact nodes by analyzing the model tire using a finite element analysis method; an average frictional energy calculation unit that extracts a specific region that exists in a region of a one-pitch tread pattern other than two tread patterns that exist at both ends in the circumferential direction among a plurality of tread patterns that exist only in a portion of the circumferential direction of the tire of the model and that are periodically repeated, the specific region being included in a region within a range of ±10 mm in the width direction from a center position in the width direction of each main groove of the tire, and that is at a distance of 2 mm to 4 mm from edges of all grooves excluding sipes, and calculates an average second frictional energy of the specific region based on the first frictional energy; A computer comprising:

Images