JP2003320824A - Method for preparing tire model - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten calculating time, while enhancing analysis accuracy. <P>SOLUTION: This method is one for preparing a tire model by modeling a tire by finite elements that can be numerically analyzed. The method includes a step Sa1 for setting a body model by modeling a tire body part in which a cord reinforcing material, a rubber part and a bead core are continuous in the same sectional shape in a tire peripheral direction by the elements, a step Sa2 for setting a ring-shaped pattern model by modeling a pattern part to be not the tire body part but a tire radial direction outside by the elements of peripheral direction pitch smaller than that of the body model, a step Sa3 for making the tire model by coupling an outer peripheral surface of the body model and an inner peripheral surface of the pattern model, and a step Sa4 for moving a node of the pattern model in a direction in which outer peripheral surface and inner peripheral surface of the pattern model approach the outer peripheral surface of the body model in parallel. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of creating a tire model that can improve the accuracy of analysis of a pattern portion that comes into contact with a road surface without significantly increasing the number of elements.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
The development of tires has been a repetitive process of making prototypes, experimenting with them, and making prototypes of improved products based on the experimental results. This method requires a large amount of cost and time for manufacturing a prototype and an experiment, and thus there is a limit to improvement of development efficiency. In order to overcome such a problem, in recent years, a method of predicting / analyzing the performance to some extent by computer simulation using a numerical analysis method or the like has been proposed without trial manufacture of a tire.

Various numerical analysis methods are used for computer simulation, and for example, the finite element method is well known. This finite element method (Finite Eleme
nt Method), the tire T as shown in FIG.
Is replaced with a tire model m consisting of a finite number of elements e, e ..., And various boundary conditions are given to this to analyze the entire system.

In such a numerical analysis method, the accuracy of analysis can be improved as the tire T is divided into smaller elements e. However, if the division is performed by the small element e, the number of elements included in the tire model m increases, and there is a drawback that the calculation time required for the analysis becomes extremely long. In other words, improving analysis accuracy and shortening calculation time are trade-offs.

Further, as exaggeratedly shown in FIGS. 20 (A) and 20 (B), in an actual tire T, a pattern portion a which comes into contact with the road surface has a smooth circular contour, but in the tire model m, the element e It becomes a polygonal shape with each node n as an apex. Therefore,
When the number of elements of the tire model m is reduced in order to shorten the calculation time, the pattern part b becomes uneven, and for example, an analysis different from the actual running situation such that the vertical force vibrates greatly when rolling simulation is performed. There is a drawback that shows the results.

The present invention has been devised in view of the above problems, and a body model setting step for setting a body model in which a tire body portion including a carcass, a belt, etc. is modeled with elements, and the body model setting step. A ring-shaped pattern model that is modeled with an element having a smaller circumferential pitch than the model is set, and the tire model is combined with the outer peripheral surface of the body model and the inner peripheral surface of the pattern model. On the basis of moving the nodes of the pattern model so that the outer peripheral surface and the inner peripheral surface of the pattern model approach the outer peripheral surface of the body model, the accuracy of analysis is improved while suppressing an increase in calculation time. The purpose is to provide a method of creating a tire model that is useful for.

[0007]

The invention according to claim 1 of the present invention is a tire model producing method for producing a tire model in which a tire to be evaluated is modeled by a finite number of elements capable of numerical analysis. A body model in which a tire body portion in which at least a carcass, a cord reinforcing material including a belt, a sidewall rubber portion, a rubber portion including a bead rubber, and a bead core are continuous in the tire circumferential direction with the same cross-sectional shape is used as an element. And a pattern model for setting a ring-shaped pattern model in which a pattern portion that is outside in the tire radial direction with respect to the tire body portion is modeled with elements having a circumferential pitch smaller than that of the body model. Setting step,
A coupling step of coupling the outer peripheral surface of the body model and the inner peripheral surface of the pattern model to form a tire model, and in the tire model, the outer peripheral surface of the pattern model,
And a deforming step of moving a node of the pattern model in a direction approaching parallel to the outer peripheral surface of the body model.

According to a second aspect of the present invention, in the deforming step, the outer peripheral surface of the pattern model is set parallel to the outer peripheral surface of the body model, and the thickness of the pattern model from the outer peripheral surface of the body model is substantially set. 2. The method for creating a tire model according to claim 1, wherein the tire model is made constant.

According to a third aspect of the present invention, in the deforming step, the amount of movement of each node required to make the outer peripheral surface of the pattern model parallel to the outer peripheral surface of the body model is 0.3 to 0. The tire model producing method according to claim 1, wherein each of the nodes is moved with a movement amount of 7 times.

According to a fourth aspect of the present invention, in the pattern model, the circumferential pitch of the elements is 1 / n of the circumferential pitch of the elements of the body model (where n is an integer of 2 or more). The method for producing a tire model according to any one of claims 1 to 3, wherein:

According to the invention of claim 5, in the body model setting step, the nodes defined in the tire meridian section of the tire body portion are continuously arranged around a virtual tire rotation axis at a circumferential pitch. The method for creating a tire model according to any one of claims 1 to 4, wherein the body model is set including a copying process.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, an example of simulating the performance of a passenger car radial tire (hereinafter, simply referred to as a tire) T as shown in FIG. 1 is illustrated. The tire T is a carcass 1 including a carcass ply 16a folded around the bead core 15 of the bead portion 14 from the tread portion 12 through the sidewall portion 13.
A cord reinforcing material F including a cord layer 6 and a belt layer 17 disposed outside the carcass 16 in the tire radial direction and inside the tread portion 12.

The carcass ply 16a is formed by covering a carcass cord made of an organic fiber cord such as polyester with a topping rubber. Further, in the belt layer 17, in the present example, two belt plies 17 are formed by arranging belt cords made of steel at a small angle (for example, about 10 to 25 degrees) with respect to the tire circumferential direction.
A and 17B are overlapped in a direction in which the belt cords intersect each other. The cord reinforcing material F includes
In addition to the carcass 16 and the belt layer 17, various plies such as a band ply and a bead reinforcing ply may be included.

A vertical groove G1 extending in the tire circumferential direction and a lateral groove G2 extending in a direction intersecting with the vertical groove G1 are formed in the tread portion 12. In this example, the vertical groove G1 and the horizontal groove G2
And the groove depth are the same.

In the tire T, a tread rubber 20, a sidewall rubber 21, a bead rubber 22 and the like are arranged outside the cord reinforcing material F. A bead apex rubber 18 is provided on the bead portion 14 so as to extend outward in the tire radial direction in a tapered shape. The tread rubber 20
Are arranged on the outer side in the radial direction of the belt layer 17.
The tread rubber 20 includes a base rubber portion 20a arranged between the groove bottom line L1 of the vertical groove G1 and the horizontal groove G2 and the outer surface of the belt layer 7 in the tire meridional section, and a tread rubber 20 arranged outside the base rubber portion 20a. By including the surface of the tread portion 12, it can be physically or virtually divided into the cap rubber portion 20b that comes into contact with the road surface.

The present invention provides a method for creating a tire model 2 in which such a tire T to be evaluated is modeled by a finite number of elements that can be numerically analyzed. The computer apparatus 1 as shown in FIG. 2 is preferably used for such a method. The computer device 1 includes a main body 1a.
And a keyboard 1b and a mouse 1c as input means,
It is composed of a display device 1d as an output means. Although not shown, the main body 1a includes a storage device such as an arithmetic processing unit (CPU), a ROM, a working memory, a large-capacity storage device such as a magnetic disk, and a storage device such as a CD-ROM or a flexible disk drive 1a1 or 1a2. Equipped appropriately. The processing procedure (program) for executing the method described later is stored in the storage device in advance. EWSa is preferably used.

FIG. 3 shows a flowchart as an example of the tire model creating method of the present embodiment. First, in the present embodiment, a body model 2 in which the tire body portion B continuous with the same cross-sectional shape (and preferably substantially the same material) in the tire circumferential direction is modeled by an element is set (body model setting step S1). . In the present embodiment, the tire body portion B includes the cord reinforcing material F including the carcass 16 and the belt 17, the sidewall rubber 21 and the bead rubber 2.
2, a bead apex rubber 18, an inner liner rubber 19, a rubber portion including a base rubber portion 20a of the tread rubber 20, and a bead core 15 are defined as a toroidal body. That is, the tire body portion B of the present embodiment
Is the cap rubber portion 2 of the tread rubber 20 from the tire T.
It is defined as the part excluding 0b.

FIG. 4 is a perspective view showing an example of this body model 3, and FIG. 5 is a flow chart showing an example for setting such a body model 3. In this example, as shown in FIG. 6, the node n is defined in the meridional section including the tire rotation axis of the tire body B (step S1).
1). The node n is a dividing point for dividing the tire body portion, which is a continuum, into a finite number of elements, and is at least on the contour line of the tire body portion B and the physical portion such as the boundary portion between the cord reinforcing material F and the rubber portion. Specifically, it is desirable to determine the interface between the portions where the materials are different, and further the position where each material is divided into minute regions. Then, the coordinates (X
i, Yi, Zi) are stored in the storage unit of the computer device 1.

The method of arranging the nodes n can be variously implemented in accordance with a customary method without any particular limitation. However, if the number of nodes included in the one meridian section is too small, the accuracy of analysis tends to decrease, and conversely. If it is too large, the calculation time tends to be long, which is not preferable. From this point of view, the number of nodes included in the one meridian section is preferably about, and more preferably
It is desirable to set the degree.

Next, in this embodiment, as shown in FIG.
A process of continuously copying each node n defined in the one meridian section around the virtual tire rotation axis at the circumferential pitch Sa (step S12). That is, any node n1
Are sequentially copied over one round of the tire in the order of n2, n3 .... If the circumferential pitch Sa is too small, the number of nodes will remarkably increase, and if it is too large, the modeling of the body model will be rough, and the analysis accuracy will be likely to decrease. From this point of view, although not particularly limited, when not focusing on one portion of the tire as in cornering simulation, for example, the circumferential pitch Sa is 2 to 10 ° in angular pitch with respect to the tire rotation axis, and more preferably 4 to. It is desirable to set the angle constant at about 8 °. On the other hand, when paying attention to the ground contact portion with the projection as in the case of overcoming a protrusion, the vicinity of the ground contact portion is set to 1 to 15 °, more preferably 1 to 9 °, and the other portions are set to the angle. Greater than
For example, it is desirable that the angle is about 10 to 12 °.

Next, each node ni that is adjacent in the tire circumferential direction
, Ni + 1 (i is a natural number) are appropriately connected to each other to form an element (step S13). This is shown in FIG.
As shown in FIG. 8A, other nodes in the tire meridian section are taken in and defined as a three-dimensional element such as a hexahedral element e1 or a pentahedral element e2. It can be set as a planar element such as the shape element e3. For example, it is preferable that the rubber portion, the bead core and the like are made into three-dimensional elements, and the cord reinforcing material F is made into an element as a plane element. For each element, material properties such as elastic modulus and rigidity of each rubber modeled by them and cords are defined and stored in the storage device. In the case of the three-dimensional element, each surface forming the element is not a curved surface but a flat surface. Therefore, the outer peripheral surface 3o of the body model 3
The contour is not a circle but a polygonal shape approximated to a circle.

Particularly preferably, as shown in FIG. 9, in the minute area of the cord reinforcing material F, the cord material c is formed into the quadrilateral membrane element 5.
The hexagonal solid elements 5c and 5 are used for the topping rubber tg which covers the cord materials a and 5b.
It is desirable to use the cord reinforcement material model 5 modeled by d and 5e. The thickness of the quadrilateral membrane element 5a is, for example, the diameter of the cord material c, and an orthotropic material having different rigidity in the arrangement direction of the cord material c and the direction orthogonal to this is defined. Also, the topping rubber t of the cord reinforcing material F
It is desirable that the hexahedral solid elements 5c to 5e representing g be defined as, for example, a super viscoelastic material like other rubber members.

By performing the above processing, FIG.
It is possible to set the body model 3 as shown in FIG. The method of setting the body model 3 is not limited to the above, and can be set by, for example, capturing data from three-dimensional CAD data.

Next, in this embodiment, as visualized in FIG. 10 and its partially expanded view, FIG. 11, a process of setting the pattern model 4 modeling the pattern portion P is performed (pattern model setting step). S2). The pattern model setting step S2 may be performed before the body model setting step S1 or may be performed in parallel. As shown in FIG. 1, the pattern portion P is a portion formed outside the tire body portion B,
In this example, the cap rubber portion 20b (however, the bottom surfaces of the vertical groove G1 and the horizontal groove G2 are not included) corresponds to this.

The pattern portion P has a vertical groove G1 and a horizontal groove G2.
Due to the concave portions, the cross-sectional shape is not continuous in the tire circumferential direction. Therefore, it cannot be modeled like the tire body B. The pattern model 4 has a ring shape having an outer peripheral surface 4o that is to be grounded to the road surface in calculation, and an inner peripheral surface 4i that is computationally coupled to the body model 3, and is mainly composed of the three-dimensional element, Preferably, the vertical groove G1, the horizontal groove G2, and the siping are also faithfully modeled by appropriately combining tetrahedral elements or hexahedral elements that are relatively easy to model even a complicated groove shape. Although not particularly limited, the modeling can be performed by a method of diverting the coordinate value of each part from the three-dimensional CAD data, a method of using a general-purpose modeling program, or the like.

The pattern model 4 is modeled by a finite number of elements 4a, 4b ... With a circumferential pitch Sb smaller than that of the body model 3. The circumferential pitch Sb may be constant in each part in the tire axial direction,
It can also be different as in this example. In any case, it is set smaller than the circumferential pitch Sa of the body model 3. This is because in the pattern portion P, complicated stress and strain are generated by repeatedly contacting and releasing the road surface, so that such movement of the pattern portion P is studied in more detail. From this point of view, although not particularly limited, the circumferential pitch Sb of the elements of the pattern model 4 is the circumferential pitch Sa of the elements of the body model 3.
It is preferably 1/2 to 1/20. Further, the pitch ratio (Sb / Sa) is 1 / n (where n is an integer of 2 or more)
Is desirable.

Next, in this embodiment, the body model 3 is used.
By connecting the outer peripheral surface 3o and the inner peripheral surface 4i of the pattern model 4 as shown in FIG.
Perform the process of setting the tire model 2 (combining step S
3). The connection numerically connects the outer peripheral surface 3o of the body model 3 and the inner peripheral surface 4i of the pattern model 4,
In other words, as exaggeratedly shown in FIG. 13, the planes p1, p2 ... Forming the outer peripheral surface 3o of the body model 3 are ...
Means that the boundary condition is determined so that the relative distance between each node n appearing on the inner peripheral surface 4i of the pattern model 4 facing the outer peripheral surface 3o is not displaced. This condition is maintained even when the tire model 2 is deformed.

In the present invention, since the pitch in the circumferential direction when modeling is different between the body model 3 and the pattern model 4, it is not possible to share all the nodes at the joint portion of both members. Rather, if the nodes are to be shared, it is necessary to perform modeling in accordance with any of the circumferential pitches, resulting in a decrease in analysis accuracy or a significant increase in calculation time as described above. Therefore, as in the present invention, the body model 3 and the pattern model 4 are analyzed by combining the body model 3 and the pattern model 4 as described above while differentiating the circumferential pitch in modeling. It is possible to prevent a decrease in accuracy and a significant increase in calculation time. If a plurality of types of pattern models 4 having different patterns are prepared in the tire model 2, only the pattern model 4 can be replaced and the tire models 2 having various tread patterns can be easily set.

As exaggeratedly shown in FIG. 14, in the tire model 2 of this embodiment, the circumferential pitch Sb of the pattern model 4 is smaller than the circumferential pitch Sa of the body model 3. , Becomes smoother and more circular. Due to such a difference in shape, when the two models are combined, the thickness t of the pattern model 4 from the outer peripheral surface 3o of the body model 3 is different in the tire circumferential direction. Specifically, the thickness ta at the node position of the body model 3 becomes small, and the thickness tb at the intermediate position of the nodes adjacent to each other in the tire circumferential direction of the body model 3 becomes large (tb>
ta). In such a tire model 2, when, for example, a grounding simulation or a rolling simulation is performed, the ground pressure distribution becomes non-uniform even though it is a portion where the ground pressure is originally uniform in actual vehicle evaluation and the like. The result is far from the actual vehicle evaluation.

Therefore, in the present invention, in the tire model 2, a process of moving the nodes of the pattern model 4 in the direction in which the outer peripheral surface 4o of the pattern model 4 approaches the outer peripheral surface 3o of the body model 3 in parallel is performed. (Deformation step S4). As one mode of this deforming step S4, as shown in FIG. 15, for example, the outer peripheral surface 4o of the pattern model 4 is changed to an outer peripheral surface 4o1 parallel to the outer peripheral surface 3o of the body model 3 so that the nodes are changed. It can be moved. In this case, the thickness t of the pattern model 4 is
It is possible to make a and tb substantially constant in the tire circumferential direction. Therefore, the ground pressure can be made uniform by simulation, and an analysis result similar to that at the time of actual vehicle evaluation can be obtained.

The method of moving the node n on the outer peripheral surface of the pattern model 4 is not particularly limited, and various methods can be used. For example, as shown exaggeratedly in FIG. 16, an imaginary plane VP parallel to the outer peripheral surface 3o of the body model 3 with a thickness t is set, and the outer peripheral surface 4 of the current pattern model 4 is set.
The normal vectors j1, j2 ... From each node n appearing in o to this virtual plane VP may be obtained, and each node n may be moved based on this. The position of the node n ′ after the movement can be stored in the storage device of the computer device 1.

As another mode of the deforming step S4, the movement amount J of each node n required to make the outer peripheral surface 4o of the pattern model 4 parallel to the outer peripheral surface of the body model (this is the method described above). Each node n can be moved by a movement amount Ja that is 0.3 to 0.7 times the value given by the size of the line vectors j1, j2 ... In FIG. 16, the outer peripheral surface 4o2 of the moved pattern model 4 when the ratio (Ja / J) is set to 0.5 is indicated by a three-dot chain line.
In this example, the thickness of the pattern model 4 is not constant in the tire circumferential direction, but it is possible to maintain a smooth arc shape of the main surface of the pattern model 4 while approaching the constant thickness. This reduces unevenness of the outer peripheral surface of the pattern model 4 that comes into contact with the road surface when performing a rolling simulation for running the tire model 2 on a virtual road surface,
It is possible to effectively prevent generation of a large vibration component in the vertical direction.

If the ratio of the movement amount (Ja / J) is less than 0.3, unevenness in the thickness of the pattern model 4 is likely to appear in the deterioration of the analysis accuracy, and conversely 0.7 times. If it exceeds, the smoothness of the outer peripheral surface is impaired and polygonalization progresses, which is likely to be disadvantageous in the rolling simulation. From this point of view, the ratio of the movement amount of the nodes (Ja / J)
Is particularly preferably about 0.4 to 0.6.

[0034]

Example (Test 1) A tire model was set based on the specifications shown in Table 1. Example 1 and Example 2 are tire models (tire size 205 /
65R15). The tire model of Example 1 is shown in FIG.
As shown in FIG. 5, the outer peripheral surface of the pattern model is substantially parallel to the outer peripheral surface of the body model.
As shown by the three-dot chain line, the movement amount ratio is controlled (Ja / J = 0.5), and the aim is to achieve both smoothness of the outer peripheral surface of the pattern model and uniform thickness.
In addition, Comparative Example 1 shows that the deformation step was not performed from Examples 1 and 2, and Comparative Example 2 is the same as Comparative Example 1 but modeled according to the circumferential pitch of the body model.

[0035]

[Table 1]

Using each of the above tire models, an internal pressure of 20
A rolling simulation was performed on a flat virtual road surface at 0 kPa, rim 6.5 JJ, vertical load 4.5 kN, slip angle 1 °, speed 10 km / H. In the simulation, the cornering force obtained by the rolling running was output and the calculation time was measured. The simulation was carried out using general-purpose analysis software "LS-DYNA" and NEC SX-4 computer.
In addition, in Table 1, the measurement results of actual tires are also shown and the analysis accuracy is compared. Table 1 shows the test results and the like.

As a result of the test, it was confirmed that the working example of the example shortened the calculation time while improving the analysis accuracy. Next, Comparative Example 1 and Example 1 were simulated by statically grounding on a virtual road surface to determine the grounding shape. This is shown in FIGS. Although the distribution of the ground contact pressure is shown by the shade of color, it can be confirmed that Example 1 is more uniform than that of Comparative Example 1.

[0038]

As described above, according to the first aspect of the present invention, a body model including a carcass, a belt, and a tire body portion that is continuous in the tire circumferential direction and has the same sectional shape is modeled with elements, and the tire. A ring-shaped pattern model obtained by modeling the pattern portion, which is on the outer side in the tire radial direction with respect to the body portion, with elements having a circumferential pitch smaller than that of the body portion element model is set individually, and the outer peripheral surface of the body model is set. Since the tire model is set by combining the inner peripheral surface of the pattern model with the inner peripheral surface of the pattern model, a more detailed analysis can be performed in the pattern portion that contacts the road surface. Further, since the elements of the body model are relatively larger than those of the pattern model, it is possible to prevent the number of elements of the tire model from significantly increasing. Therefore, it is expected that the calculation time is shortened while improving the analysis accuracy.

According to the first aspect of the invention, in the tire model, the outer peripheral surface and the inner peripheral surface of the pattern model are modified so that the nodes of the pattern model are moved in a direction approaching parallel to the outer peripheral surface of the body part element model. By including the step, it is possible to further improve the analysis accuracy by reducing the change in the thickness from the outer peripheral surface of the body model to the outer peripheral surface of the pattern model based on the difference in the number of elements.

According to a second aspect of the present invention, the deforming step is performed on the outer peripheral surface and the inner peripheral surface of the pattern model.
When the thickness of the pattern model from the outer peripheral surface of the body model is set substantially parallel to the outer peripheral surface of the body part element model, the analysis accuracy of the pattern part is further improved.

Further, as in the invention according to claim 3, in the deforming step, movement of each node required for making the outer peripheral surface and the inner peripheral surface of the pattern model parallel to the outer peripheral surface of the body part element model. When each node is moved by a movement amount of 0.3 to 0.7 times the amount L, it is useful for improving the analysis accuracy of the pattern portion while maintaining the smoothness of the outer peripheral surface of the pattern model.

According to a fourth aspect of the present invention, in the pattern model, the circumferential pitch of the elements is 1 / n of the circumferential pitch of the elements of the body model (where n is an integer of 2 or more). In some cases, the calculation of the transformation step can be simplified, and the calculation time from model creation can be further shortened.

According to the invention of claim 5, in the body setting step, the nodes defined in the tire meridian section are continuously copied around the virtual tire rotation axis at a circumferential pitch. By setting the body model, the calculation time from creation of the model can be further shortened.

[Brief description of drawings]

FIG. 1 is a sectional view of a tire.

FIG. 2 is a perspective view showing an example of a computer device.

FIG. 3 is a flowchart showing an example of a processing procedure of the present invention.

FIG. 4 is a perspective view showing an example of a body model.

FIG. 5 is a flowchart showing an example of a body model setting step.

FIG. 6 is a sectional view of a body model.

FIG. 7 is a perspective view illustrating a method for setting a body model.

8A and 8B are perspective views illustrating elementization.

FIG. 9 is a conceptual diagram showing modeling of a cord reinforcing material.

FIG. 10 is a perspective view of a pattern model.

FIG. 11 is a development view of a pattern model.

FIG. 12 is a development view of a tire model.

FIG. 13 is a schematic side view illustrating a combination of a body model and a pattern model.

FIG. 14 is a schematic side view illustrating a combination of a body model and a pattern model.

FIG. 15 is a schematic side view illustrating a modification step of a pattern model.

FIG. 16 is an enlarged side view schematically showing another example of the deformation step of the pattern model.

FIG. 17 is a ground pressure distribution diagram of the first embodiment.

FIG. 18 is a ground pressure distribution diagram of Comparative Example 1.

19A is a perspective view showing a tire, and FIG. 19B is a perspective view showing a tire model thereof.

20A is a perspective view showing a tread surface of a tire, and FIG. 20B is a perspective view showing a tread surface of a tire model.

[Explanation of symbols]

T tire 2 tire model 3 body models 4 pattern models 5 Cord reinforcement element model 7 virtual road surface

Claims (5)

[Claims] 1. A tire model creating method for creating a tire model in which a tire to be evaluated is modeled by a finite number of elements capable of numerical analysis, comprising a cord reinforcing material including at least a carcass and a belt, and a side. A body model setting step for setting a body model in which a rubber body including a wall rubber and a bead rubber and a bead core are modeled with elements of a tire body section in which the tire core section is continuous in the same sectional shape in the tire circumferential direction; A pattern model setting step of setting a ring-shaped pattern model in which a pattern portion forming a radially outer side is modeled at a circumferential pitch smaller than that of the body model; an outer peripheral surface of the body model and an inner peripheral surface of the pattern model. A step of combining and to set a tire model, and And a deforming step of moving the nodes of the pattern model so that the outer peripheral surface of the pattern model approaches the outer peripheral surface of the body model in parallel to the outer peripheral surface of the body model. 2. The method for producing a tire model according to claim 1, wherein in the deforming step, the outer peripheral surface of the pattern model is made substantially parallel to the outer peripheral surface of the body model. 3. The transforming step is a movement of 0.3 to 0.7 times the movement amount of each node required to make the outer peripheral surface of the pattern model substantially parallel to the outer peripheral surface of the body model. The method for creating a tire model according to claim 1, wherein each of the nodes is moved by an amount. 4. In the pattern model, the circumferential pitch of the elements is 1 / the circumferential pitch of the elements of the body model.
The method for producing a tire model according to any one of claims 1 to 3, wherein n (where n is an integer of 2 or more). 5. The body model setting step includes a process of continuously copying each node defined in a tire meridian section of the tire body portion around a virtual tire rotation axis at a small circumferential pitch. Claim 1 characterized by the above-mentioned.
5. The method for creating a tire model according to any one of 4 to 4.