JP2011148468A - Simulation method and simulation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simulation method and a simulation device capable of analyzing a deformation state of a tire with a high degree of accuracy. <P>SOLUTION: The simulation method includes a step S101 for setting a tire model 1, a step S102 for setting material constants for a belt layer model 2 and a ply layer model 3 composing the tire model 1 and a step S103 for calculating an evaluation value by a simulation using the tire model 1. In the step S101, in the belt layer model 2, an angle formed by an axial direction D<SB>A</SB>of a reinforcing code in a center region A and a circumferential direction D1 of the tire model 1 is set to be smaller than an angle formed by axial directions D<SB>B</SB>, D<SB>C</SB>of the reinforcing code in the shoulder regions B, C and the circumferential direction D1 of the tire model 1. In the step S102, elastic moduli in the axial directions D<SB>A</SB>to D<SB>C</SB>of the reinforcing code which should be set for the ply layer model 3 as the material constants are changed within a range in which distortions in the axial directions D<SB>A</SB>to D<SB>C</SB>of the reinforcing code of the ply layer model 3 are smaller than a predetermined threshold value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a simulation method and a simulation apparatus.

  2. Description of the Related Art Conventionally, a technique for analyzing a deformation state when a tire is filled with an internal pressure or under a load is known by a simulation method using a tire model.

  In such a simulation method, Patent Literature 1 and Patent Literature 2 disclose a technique for giving different material constants to the tension side and the compression side of the reinforcing material model constituting the tire model.

JP 2003-94916 A JP 2004-102424 A

  However, in the above-described conventional technology, the amount of deflection of the tire and the cornering power are analyzed, but the amount of deformation of the tread portion and the side portion of the tire is not considered.

  Therefore, when analysis is performed using conventional technology, the amount of deformation of the tread when the tire is filled with internal pressure and the amount of deformation of the side when the load is applied without filling the internal pressure in the run-flat tire are measured values. Therefore, the evaluation values such as strain and stress obtained by such analysis do not match the actual measurement values, and as a result, the durability performance and rolling resistance performance determined by such evaluation values do not match the actual measurement values. There is a problem that such analysis cannot be used in actual product design.

  Therefore, the present invention has been made in view of the above-described problems, and an object thereof is to provide a simulation method and a simulation apparatus that can analyze the deformation state of a tire with high accuracy.

  A first feature of the present invention is a simulation method, comprising: a tire model setting step for setting a tire model obtained by dividing a tire into a finite number of elements; and a belt layer model and a ply layer model constituting the tire model. A material constant setting step for setting a material constant, and an evaluation value calculation step for calculating an evaluation value by simulation using the tire model. In the tire model setting step, in the center region of the belt layer model The angle formed by the axial direction of the reinforcing cord and the circumferential direction of the tire model is set to be smaller than the angle formed by the axial direction of the reinforcing cord and the circumferential direction of the tire model in the shoulder region of the belt layer model. In the material constant setting step, the axis of the reinforcement cord of the ply layer model Range distortion is smaller than a predetermined threshold value in the direction, and gist varying the elastic modulus in the axial direction of the reinforcing cord to be set against the ply layer model as the material constant.

  In the material constant setting step of the first feature of the present invention, the material constant is set as the material constant for the ply layer model in a range where the strain in the axial direction of the reinforcing cord of the ply layer model is larger than the predetermined threshold The elastic modulus in the axial direction of the reinforcing cord may be constant.

  In the tire model setting step of the first feature of the present invention, the number of reinforcing cords per unit width in the center region of the belt layer model is the number of reinforcing cords per unit width in the shoulder region of the belt layer model. You may set so that it may increase more.

  The second feature of the present invention is a simulation device, which is characterized by executing the above-described simulation method.

  As described above, according to the present invention, it is possible to provide a simulation method and a simulation apparatus that can analyze the deformation state of a tire with high accuracy.

It is a flowchart shown about the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the tire used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a perspective view showing an example of a tire model used with a simulation method concerning a 1st embodiment of the present invention. It is sectional drawing which shows an example of the tire model used with the simulation method which concerns on the 1st Embodiment of this invention. It is a perspective view which shows an example of the reinforcement material model used with the simulation method which concerns on the 1st Embodiment of this invention. It is a top view which shows an example of the reinforcing material model used with the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating an example of the material constant set with respect to the reinforcing material model used with the simulation method which concerns on the 1st Embodiment of this invention. It is a graph which shows an example of the tension | tensile_strength and compression characteristic of the reinforcing material used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a graph which shows an example of the tension | tensile_strength and compression characteristic of the reinforcing material used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating an example of the elasticity modulus in the axial direction of the reinforcement cord of the reinforcement material used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating an example of the elasticity modulus in the axial direction of the reinforcement cord of the reinforcement material used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating an example of the elasticity modulus in the axial direction of the reinforcement cord of the reinforcement material used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating an example of the elasticity modulus in the axial direction of the reinforcement cord of the reinforcement material used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating an example of the elasticity modulus in the axial direction of the reinforcement cord of the reinforcement material used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the deformation | transformation at the time of the internal pressure filling of the tire used as the object of the simulation method which concerns on the 1st Embodiment of this invention. It is a graph shown about the amount of deformation of the tread part in the tire radial direction at the time of internal pressure filling obtained by the simulation method concerning a 1st embodiment of the present invention. It is a graph shown about the amount of deformation of the tread part in the tire radial direction at the time of internal pressure filling obtained by the simulation method concerning a 1st embodiment of the present invention. It is the schematic of the computer apparatus for performing the simulation method which concerns on the 1st Embodiment of this invention.

  A simulation method according to the first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, in step S101, a tire model 1 in which a tire is divided into a finite number of elements is set. FIG. 2 shows an example of a tire 10 that is a target of the simulation method according to the present embodiment, FIG. 3 shows a perspective view of the set tire model 1, and FIG. 4 shows a cross-sectional view of the tire model 1. Show.

  For example, the tire model 1 is digitized into a format that can be handled by a computer device by dividing the tire 10 into a plurality of elements by element division corresponding to a finite element method (FEM), that is, mesh division. It has been done.

  For example, as shown in FIGS. 3 and 4, rubber members such as the tread portion 10A and the side portion 10B, the bead wires 10C, and the like may be modeled as solid elements 1A, 1B, and 1C.

  Further, as shown in FIG. 2, the reinforcing material includes a belt layer 20 constituted by a belt 20A and a reinforcement cord 20B, and a ply layer 30 constituted by a ply 30A and a reinforcement cord 30B.

  For example, the belt 20A and the ply 30A are made of a rubber member, and the reinforcing cords 20B and 30B are steel cords composed of a plurality of filaments.

  Here, as shown in FIGS. 3 to 5, the reinforcing material such as the belt layer 20 and the ply layer 30 are modeled as anisotropic solid elements, membrane elements, and shell elements 2 and 3 having equivalent rigidity. Also good.

  That is, each of the composite material layers such as the belt layer 20 constituted by the belt 20A and the reinforcement cord 20B and the ply layer 30 constituted by the ply 30A and the reinforcement cord 30B may be modeled as uniform elements.

  Thus, by modeling the reinforcing material, the numerical value that can be handled by the computer device is called a “reinforcing material model”. Specifically, by modeling the belt layer 20, what is digitized into a format that can be handled by a computer device is referred to as “belt layer model 2”, and by modeling the ply layer 30, the computer device What is digitized into a format that can be handled by is called “ply layer model 3”.

Here, as shown in FIG. 6, in such a reinforcing material model, the angle formed by the axial direction DA of the reinforcing cord in the center region _A and the circumferential direction D1 of the tire model 1 is defined as the reinforcing cord in the shoulder regions B and C. axially D _B, may be set to be smaller than the angle formed between D _C and the circumferential direction D1 of the tire model 1.

For example, in a belt layer model 2, the angle between the circumferential direction D1 in the axial direction D _A and the tire model 1 the reinforcement cord in the center region A, shoulder regions B, axial D _B of the reinforcing cords in _C, a D _C You may set so that it may become smaller than the angle which the circumferential direction D1 of the tire model 1 makes.

  Further, in the belt layer model 2 and the ply layer model 3, the number of reinforcing cords per unit width in the center region A may be set to be different from the number of reinforcing cords per unit width in the shoulder regions B and C. .

  For example, in the belt layer model 2, the number of reinforcing cords 20B per unit width in the center region A is set to be larger than the number of reinforcing cords 20B per unit width in the shoulder regions B and C of the belt layer model 2. May be.

  In the ply layer model 3, the number of reinforcing cords 30B per unit width in the center region A may be set to be smaller than the number of reinforcing cords 30B per unit width in the shoulder regions B and C.

  By modeling in this way, the circumferential rigidity of the tire 10 in the shoulder regions B and C is reduced, the amount of deformation of the tread portion 10A at the time of internal pressure filling is increased, and closer to the actually measured value.

  In step S102, material constants are set for the reinforcing material model constituting the tire model 1, that is, the belt layer model 2 and the ply layer model 3 set in step S101. Hereinafter, a material constant to be set for such a reinforcing material model, particularly an elastic modulus (Young's modulus) in the axial direction of the reinforcing cord will be examined.

  First, an example of material constants to be considered in a general reinforcing material, particularly, a unidirectional fiber reinforcing material will be described with reference to FIG.

In FIG. 7, “L” is the axial direction of the reinforcing cord, “T” is the vertical direction of the reinforcing cord, and “V _f ” is the volume of the reinforcing cords 20B and 30B in the reinforcing members 20 and 30. “V _m ” is a volume fraction of a rubber member (for example, the belt 20A or the ply 30A) in the reinforcing members 20 and 30.

“E _f ” is the Young's modulus of the reinforcing cords 20B and 30B, “E _L ” is the Young's modulus of the reinforcing members 20 and 30 in the axial direction of the reinforcing cords 20B and 30B, and “E _T ” is The Young's modulus of the reinforcing members 20 and 30 in the vertical direction of the reinforcing cords 20B and 30B, and “E _m ” is the Young's modulus of the rubber member.

“Ν _f ” is the Poisson ratio of the reinforcing cords 20B and 30B, “ν _m ” is the Poisson ratio of the rubber member, “G _f ” is the shear rigidity of the reinforcing cords 20B and 30B, and “G “ _m ” is the shear rigidity of the rubber member, and “G _LT ” is the shear rigidity of the reinforcing members 20 and 30.

Note that “V _f ”, “V _m ”, “E _f ”, “E _L ”, “E _T ”, “E _m ”, “ν _m ”, “G _f ”, “G _m ” and “G _LT ”. "Is as shown in FIG.

  Secondly, an example of the tensile and compression characteristics of such a reinforcing material, particularly a unidirectional fiber reinforcing material, will be described with reference to FIGS.

  FIG. 8 shows an example of tensile and compression characteristics of a “rubber-rayon fiber unidirectional reinforcement” which is a kind of such a reinforcing material, and FIG. 9 shows a “rubber-nylon fiber unidirectional reinforcement” which is a kind of such a reinforcing material. 2 shows an example of tensile and compression characteristics of a “material”. Here, Figure 8 is taken from "Figure 4.37 Tensile and compressive properties of rubber-rayon fiber unidirectional reinforcement" in "Composite Technology Assembly, Editorial Committee for Composite Material Technology, Industrial Technology Center, 1976". Fig. 9 shows "Figure 4.38 Tensile and compressive properties of rubber-nylon fiber unidirectional reinforcement" in "Composite Materials Technology Assembly, Editorial Committee for Composite Materials Technology, Industrial Technology Center, 1976". Quoted from.

  As shown in FIGS. 8 and 9, the rigidity (tensile rigidity of the reinforcing material) when the above-described reinforcing material is pulled is the rigidity corresponding to the Young's modulus (tensile rigidity) of the reinforcing cord included in the reinforcing material. However, the rigidity when the above-mentioned reinforcing material is compressed (compression rigidity of the reinforcing material) is that the twisted reinforcing cord is loosened and the compressive rigidity of the reinforcing cord is low. Compared with

  In addition, as shown in FIGS. 8 and 9, the elastic modulus of the reinforcing material in the axial direction of the reinforcing cord is normally substantially constant in a range where the distortion of the reinforcing material in the axial direction of the reinforcing cord is large. In the range where the strain of the reinforcing material in the axial direction is small, the elastic modulus of the reinforcing material in the axial direction of the reinforcing cord gradually changes.

  10 to 14 illustrate the elastic modulus characteristics of the reinforcing material in the axial direction of the reinforcing cord.

  As shown in the examples of FIGS. 10 to 14, the elastic modulus of the reinforcing material in the axial direction of the reinforcing cord is substantially constant in a range where the strain of the reinforcing material in the axial direction of the reinforcing cord is larger than a predetermined threshold (1%). It is.

  In the example of FIG. 10, the elastic modulus of the reinforcing material in the axial direction of the reinforcing cord changes linearly in a range where the strain of the reinforcing material in the axial direction of the reinforcing cord is smaller than a predetermined threshold (1%).

  On the other hand, in the examples of FIGS. 11 to 14, the elastic modulus of the reinforcing material in the axial direction of the reinforcing cord is nonlinear (smooth) in a range where the strain of the reinforcing material in the axial direction of the reinforcing cord is smaller than a predetermined threshold (1%). ).

  Further, depending on the material of the reinforcing cord and rubber member and the number of reinforcing cords, as shown in FIG. 12, the range in which the elastic modulus of the reinforcing material in the axial direction of the reinforcing cord changes is widened, as shown in FIG. The range in which the elastic modulus of the reinforcing material changes in the axial direction of the reinforcing cord becomes narrow.

  Furthermore, as shown in FIG. 14, the elastic modulus of the reinforcing material in the axial direction of the reinforcing cord changes within a range due to expansion from tire molding to vulcanization inside the tire and thermal shrinkage during vulcanization. The center may deviate from “distortion = 0”.

  Thirdly, with reference to FIG. 15, the deformation at the time of filling the tire 10 with the internal pressure will be described.

  As shown in FIG. 15, when the tire 10 is filled with internal pressure, the belt layer 20 expands in the circumferential direction D1 of the tire 10 and contracts in the width direction D2 of the belt layer 20, and the ply layer 30 Contracts in the width direction D2.

  That is, the deformation amount of the tread portion 10 </ b> A when the tire 10 is filled with the internal pressure is determined based on not only the rigidity of the belt layer 20 but also the rigidity in the width direction of the ply layer 30.

  In addition, the amount of contraction in the width direction D2 of the ply layer 30 changes based on the amount of contraction in the width direction D2 of the belt layer 20, and thus is determined based on the rigidity of the belt layer 20 and the angle of the reinforcement cord 20B.

  On the other hand, when the tire 10 is filled with the internal pressure, the side portion 10 </ b> B bulges in the width direction of the tire 10. Such deformation of the side portion 10 </ b> B is affected by deformation in the tensile direction generated in the ply layer 30. That is, the deformation of the side portion 10 </ b> B is determined based on the rigidity in the width direction of the ply layer 30.

  That is, in order to accurately predict the deformation of the entire tire 10 including the tread portion 10A and the side portion 10B when the tire 10 is filled with internal pressure, it is necessary to consider the tensile stiffness and the compression stiffness of the ply layer 30 as well. .

  In consideration of the contents of FIGS. 7 to 15 described above, in step S102, the material constants, in particular, the axial directions of the reinforcement cords 20, 30 with respect to the reinforcing material model, that is, the belt layer model 2 and the ply layer model 3. The elastic modulus (Young's modulus) at is set.

For example, the above-described “V _f ”, “V _m ”, “E _f ”, “E _L ”, “E _T ”, “E _m ” are used as material constants for the belt layer model 2 and the ply layer model 3. Alternatively, a part or all of “ν _m ”, “G _f ”, “G _m ”, and “G _LT ” may be set.

  Specifically, in step S102, the elastic modulus in the axial direction of the reinforcing cords 20 and 30 to be set for the belt layer model 2 and the ply layer model 3 is set as the belt layer model 2 in the axial direction of the reinforcing cords 20 and 30. And the distortion of the ply layer model 3 is changed in a range smaller than a predetermined threshold value.

  In addition, in the above-described large strain range, by making the change in the elastic modulus in the axial direction of the reinforcing cords 20 and 30 constant, it is possible to reduce the portion where nonlinear calculation is performed, and to reduce the calculation cost, Calculations can be easily converged and modeling can be facilitated.

  Here, in step S102, a plurality of elastic moduli may be set for the belt layer model 2 and the ply layer model 3 in consideration of the arrangement and direction of the reinforcing cords 20 and 30.

  Thereafter, in step S103, an evaluation value (for example, a deformation amount of each part of the tire model 1) is calculated by a simulation using the tire model 1 described above, for example, by a finite element method.

  First, referring to FIG. 16, simulation results when each of the “initial model”, “bilinear” and “bilinear adjustment” is used as the tire model (the tire radius of the tread portion 10 </ b> A when the tire 10 is filled with the internal pressure) The amount of deformation in the direction) is compared with the measured value.

  The actual measurement value indicates a result of measuring the deformation amount in the tire radial direction of the tread portion 10A when the tire 10 is filled with the internal pressure using the laser in the width direction of the tread portion 10A.

  The “initial model” is a tire model in which the reinforcement cords 20B and 30B are modeled as linear elastic bodies without changing the elastic modulus in the axial direction of the reinforcement cords set for the belt layer model 2 and the ply layer model 3. .

  “Bilinear” is a tire model in which the elastic modulus in the axial direction of the reinforcing cord to be set for the belt layer model 2 and the ply layer model 3 is changed.

  Here, in the case of “bilinear”, in the axial direction of the reinforcing cords set for the belt layer model 2 and the ply layer model 3 in a range where the distortion in the axial direction of the reinforcing cords of the belt layer model 2 and the ply layer model 3 is large. The elastic modulus was made constant. The elastic modulus when the reinforcing material models 2 and 3 are pulled is set to be higher than the elastic modulus when the reinforcing material models 2 and 3 are compressed.

  In addition, the elastic modulus in the axial direction of the reinforcing cord set for the belt layer model 2 and the ply layer model 3 is smoothly changed in a range where the distortion in the axial direction of the reinforcing cord of the belt layer model 2 and the ply layer model 3 is small. I let you. Here, the range in which the strain is small is a range from “−0.2%” to “+ 0.2%”.

  “Bilinear adjustment” is a tread portion 10A in which the deformation amount of the tread portion 10A corresponding to the center region A of the ply layer 30 corresponds to the shoulder regions B and C of the ply layer 30. The range in which the elastic modulus in the axial direction of the reinforcing cord set for the ply layer 30 changes was adjusted so as to be smaller than the deformation amount.

  Specifically, the strain range in which the elastic modulus changes in the center region A in the width direction 30 mm of the ply layer 30 was expanded from “−0.4%” to “+ 0.2%”.

  In “bilinear adjustment”, the belt layer 20 was modeled in the same manner as “bilinear”.

As a result, the ratio between the displacement amount of the tread portion 10A in the center region A and the deformation amount of the tread portion 10A in the shoulder regions B and C in the “bilinear adjustment” is close to the actually measured value as shown in (Table 1). became.

  Second, referring to FIG. 17, a simulation result when each of “initial model”, “bilinear adjustment”, “belt angle”, and “both” is used as a tire model (a tread when the tire 10 is filled with internal pressure). The amount of deformation of the portion 10A in the tire radial direction) is compared with the actually measured value.

  The “belt angle” is a tire model obtained by improving the “initial model” in consideration of a change in the belt radius R in the cross section of the tire 10. In the “belt angle”, “cos θ / R = constant”. Here, “θ” is an angle formed by the axial direction of the reinforcing cord 20B in the belt layer 20 and the circumferential direction of the tire 10 (that is, a belt angle), and “R” is a belt radius in the cross section of the tire 10. is there.

  “Both” is a tire model that combines “bilinear adjustment” and “belt angle”.

As a result, in “both”, as shown in (Table 2), the circumferential extension of the tire 10 in the vicinity of the center region A of the belt layer 20 can be accurately predicted, and the elasticity of the ply layer 30 when compressed The change in rate can be modeled with high accuracy, and a greater improvement effect can be achieved.

  As shown in FIG. 18, the simulation apparatus that executes the simulation method according to the present embodiment may be realized by a computer apparatus, or may be implemented by a software module executed by a processor of the computer apparatus. However, it may be implemented by a combination of both.

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  According to the simulation method according to the first embodiment of the present invention, by changing the elastic modulus in the axial direction of the reinforcing cord set for the belt layer model 2 and the ply layer model 3, the tire can be deformed with high accuracy. The state can be analyzed.

(Comparison evaluation)
Next, in order to further clarify the effects of the present invention, the evaluation values calculated by the simulation method using the conventional models 1 and 2 and the new models 1 to 3 according to the present invention as tire models are compared with actual measurement values. The evaluation results will be described. In addition, this invention is not limited at all by these examples.

  In this comparative evaluation, the tire model 1 of the passenger car tire size 235 / 45R18 is assembled to the wheel model 2 of the rim size 8J × 18, filled with an internal pressure of 230 kPa, and after measuring the shape of the tread portion 10A, the internal pressure is set to 0 kPa. Again, the shape of the tread portion 10A was measured.

  And the difference of the measurement result was taken for the shape of the two tread portions 10A, and the amount of deformation in the tire radial direction of the tread portion 10A in the internal pressure filling character was calculated.

  Here, the structure of the belt layer 20 of the tire 10 used for the comparative evaluation is obtained by adding a cap and a layer to two steel crossings.

  That is, in the simulation method described above, an FEM tire model 1 was created based on the cross-sectional shape of the tire 10A in an internal pressure state of 0 kPa, and the tire model 1 was filled with an internal pressure of 230 kPa.

  The conventional model 1 is a tire model in which a value calculated by a material test (tensile test) is used as the elastic modulus in the axial direction of the reinforcing cord set for the belt layer model 2 and the ply layer model 3.

  The conventional model 2 is a material test as the elastic modulus when the belt layer model 2 and the ply layer model 3 are pulled out of the elastic modulus in the axial direction of the reinforcing cord set for the belt layer model 2 and the ply layer model 3. The tire model uses the value calculated by the (tensile test) and the value calculated by the material test (compression test) as the elastic modulus when the belt layer model 2 and the ply layer model 3 are compressed. .

  In the conventional model 2, the elastic modulus is nonlinear in the range where the strain in the axial direction of the reinforcing cords of the belt layer model 2 and the ply layer model 3 is “−0.2%” to “+ 0.2%”. It was set to change smoothly.

  In the new model 1, the belt layer model 2 and the ply layer model 3 are pulled out of the elastic modulus in the axial direction of the reinforcing cord set for the belt layer model 2 and the ply layer model 3 as in the conventional model 2. The value calculated by the material test (tensile test) is used as the elastic modulus in the case, and the value calculated by the material test (compression test) is used as the elastic modulus when the belt layer model 2 and the ply layer model 3 are compressed. This is the tire model used.

  In the new model 1, the axial strain of the reinforcing cord of the belt layer model 2 is within the range of “−0.2%” to “+ 0.2%” in the axial direction of the reinforcing cord of the belt layer model 2. The elastic modulus is set so as to change nonlinearly (smoothly), and the strain in the axial direction of the reinforcing cord of the ply layer model 3 is in the range from “−0.4%” to “+ 0.2%”. The elastic modulus in the axial direction of the reinforcing cord of the layer model 3 was set so as to change nonlinearly (smoothly).

  The new model 2 is a tire model in which the belt angle in the shoulder regions B and C is 2 ° larger than the belt angle in the center region A (2/3 of the whole) of the belt layer model 2 in addition to the contents of the new model 1 It is.

  In addition to the contents of the new model 2, the new model 3 has a higher per unit width in the shoulder regions B and C than the number of reinforcing cords per unit width in the center region A (3/4 of the whole) of the belt layer model 2. This is a tire model in which the number of reinforcing cords is reduced by 10%.

(Table 3) shows, for each tire model, the difference between the maximum deformation amount of the tread portion 10A in the center region A and the maximum deformation amount of the tread portion 10A in the shoulder regions B and C, and the tread portion 10A at the end of the belt layer. The amount of deformation is shown.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

DESCRIPTION OF SYMBOLS 1 ... Tire model, 2 ... Belt layer model, 3 ... Ply layer model, A ... Center area | region, B, C ... Shoulder area | region

Claims (4)

A tire model setting step for setting a tire model in which a tire is divided into a finite number of elements;
A material constant setting step for setting material constants for the belt layer model and the ply layer model constituting the tire model;
An evaluation value calculating step of calculating an evaluation value by simulation using the tire model,
In the tire model setting step, an angle formed by the axial direction of the reinforcing cord in the center region of the belt layer model and the circumferential direction of the tire model is determined by calculating the axial direction of the reinforcing cord in the shoulder region of the belt layer model and the tire. Set it to be smaller than the angle formed by the circumferential direction of the model,
In the material constant setting step, the elasticity in the axial direction of the reinforcement cord to be set for the ply layer model as the material constant is within a range in which the strain in the axial direction of the reinforcement cord of the ply layer model is smaller than a predetermined threshold. A simulation method characterized by changing a rate.   In the material constant setting step, in the axial direction of the reinforcement cord to be set for the ply layer model as the material constant, the strain in the axial direction of the reinforcement cord of the ply layer model is larger than the predetermined threshold. The simulation method according to claim 1, wherein the elastic modulus is made constant.   In the tire model setting step, the number of reinforcing cords per unit width in the center region of the belt layer model is set to be larger than the number of reinforcing cords per unit width in the shoulder region of the belt layer model. The simulation method according to claim 1, wherein:   The simulation apparatus characterized by performing the simulation method according to any one of claims 1 to 3.

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