JP6363879B2 - How to create a tire model - Google Patents

Description

  The present invention relates to a method for creating a tire model that can accurately reproduce the shape of a pneumatic tire manufactured through vulcanization molding using a mold, and that is useful for accurate performance analysis.

  In recent years, various pneumatic tire simulation methods using a computer have been proposed. In this simulation, a tire model is created based on a pneumatic tire to be analyzed. The tire model is obtained by discretizing a continuous pneumatic tire with a finite number of elements (hereinafter, simply referred to as “modeling”). For each element of the tire model, a material property value of the pneumatic tire to be analyzed is defined.

  There are two-dimensional models and three-dimensional models as tire models. The two-dimensional model is a meridian cross-sectional model including the rotation axis of the tire. On the other hand, the three-dimensional model is created by developing the tire cross-sectional shape of the two-dimensional model in the tire circumferential direction. As a two-dimensional tire cross-sectional shape, a cross-sectional shape of a pneumatic tire that actually exists or a cross-sectional shape of a mold for forming a pneumatic tire is used.

  Generally, since a pneumatic tire undergoes thermal shrinkage of each member after vulcanization, its two-dimensional cross-sectional shape is slightly different from the cross-sectional shape of a mold obtained by vulcanization molding. For this reason, the tire model created based on the cross-sectional shape of the mold has a problem that the analysis accuracy of the simulation is low unlike the actual shape of the pneumatic tire.

  On the other hand, a tire model created from a cross-sectional shape of a pneumatic tire that actually exists has a small problem as described above. However, at the stage of development where a pneumatic tire has not yet been actually produced, it is necessary to predict the actual cross-sectional shape of the pneumatic tire based on the cross-sectional shape diagram of the mold on the desk.

  Patent Document 1 below discloses a step of correcting the angle of the belt cord set in the tire model. More specifically, the angle of the belt cord of the tire model with respect to the tire circumferential direction is corrected based on a change due to expansion of the belt ply during vulcanization molding.

JP 2013-75634 A

  As described above, even when the change in the inclination angle of the belt cord based on the expansion change of the belt ply during vulcanization molding is given to the tire model, the reproducibility to the cross-sectional shape of the actual pneumatic tire is further increased. There was room for improvement.

  As a result of intensive studies, the inventors have obtained the knowledge that one of the main causes is the meandering of the reinforcement cord of the ply of an actual pneumatic tire.

  FIG. 4 shows a development view of the carcass 6 and the belt layer 7 disposed inside the pneumatic tire. As shown in FIG. 4, the angle of the belt cord 7c with respect to the tire circumferential direction of the belt layer 7 is generally closer to the tread end side than the tread center part (tire equator C) side based on the curvature of the belt ply. Is big. That is, the belt cord 7c meanders in a substantially S shape in a developed view.

  In particular, as in the pneumatic tire 2 for a motorcycle shown in FIG. 3, when the outer surface of the tread portion 2a is greatly curved in a convex shape outward in the tire radial direction, the belt cord 7c has an S-shape. There is a tendency for meandering to appear more prominently. Further, such meandering of the cord is not as large as that of the belt layer 7, but similarly occurs in the carcass cord 6 c of the carcass 6.

  FIG. 5 shows an example of one belt cord 7c of FIG. 3, where the phantom line is an image before filling with internal pressure and the solid line is an image after filling with internal pressure. When the pneumatic tire is inflated by filling with the internal pressure, the belt cord 7c is pulled. The belt cord 7c that has been bent into an S shape undergoes a change (a change that approaches a straight line from the S shape) so that the angle difference between the central portion and the end portion becomes small. By such a change in the belt cord 7c, the length L in the tire circumferential direction and the length W in the width direction of each belt cord 7c increase. Among these, the increase in the length in the tire circumferential direction makes the pneumatic tire more easily inflated.

  However, in the conventional simulation, such a change of the belt cord 7c that approaches a straight line from the S-shape is not considered at all.

  The present invention has been devised in view of the actual situation as described above, and considering the change approaching the straight line of the cord meandering in an S shape when the pneumatic tire is inflated and deformed, from the sectional shape of the mold An object of the present invention is to provide a method for making a tire model that can accurately predict or reproduce the cross-sectional shape or the like of a pneumatic tire and that is useful for accurate performance analysis.

The present invention uses a computer for a tire model for analyzing the performance of a pneumatic tire reinforced with a ply that is at least one cord layer and vulcanized with a mold. A tire model including a ply model in which the ply is modeled by a finite number of elements based on a cross-sectional shape of the mold, and each element of the tire model, Defining a material property value according to the pneumatic tire; defining a ply model cord inclination angle based on an expansion change of the ply during the vulcanization molding; and the ply and stretching step of stretching the model seen including, the stretching step, when the tire model is a two-dimensional model, in a width direction of the ply model length Characterized in that to extend.

The present invention uses a computer for a tire model for analyzing the performance of a pneumatic tire reinforced with a ply that is at least one cord layer and vulcanized with a mold. A tire model including a ply model in which the ply is modeled by a finite number of elements based on a cross-sectional shape of the mold, and each element of the tire model, Defining a material property value according to the pneumatic tire; defining a ply model cord inclination angle based on an expansion change of the ply during the vulcanization molding; and the ply A stretching step for stretching a model, and when the tire model is a three-dimensional model, the stretching step includes a tire circumferential direction of the ply model. Characterized in that extending the length of the fine width.

  In the tire model creation method according to the present invention, after the code angle defining step and the expansion step are executed, the tire model is subjected to an expansion deformation calculation based on predetermined rim assembly conditions and internal pressure conditions. It is desirable to further include a step.

  In the tire model creation method according to the present invention, the ply model includes a belt layer model obtained by modeling a belt layer including a belt ply arranged in a tread portion, and the cord angle defining step and the extending step include the step Desirably this is done for the belt layer model.

  In the method of the present invention, first, a tire model including a ply model in which a ply is modeled by a finite number of elements is obtained based on the cross-sectional shape of the mold. For each element of the tire model, material property values according to the pneumatic tire are defined.

  Next, in the method of the present invention, a code angle defining step is performed for defining a tilt angle of the cord of the ply model based on the expansion change of the ply in the mold. The cord angle defining step reproduces the change in the inclination angle of the cord based on the expansion of the ply during vulcanization molding in the tire model. Therefore, the ply of the tire model approaches the ply of the actual pneumatic tire.

  Furthermore, in the method of the present invention, an extension step of extending the ply model is performed. In the background art column, as described as a representative example of the belt cord, when the tire is inflated and deformed due to the internal pressure filling, the cord of the ply meandering in an S-shape approaches a straight line, and the tire is further easily swelled. In the present invention, the expansion step is performed so that the ply model can reproduce the ease of swelling of the tire.

  As described above, in the method of the present invention, the ply change at the time of vulcanization molding is given to the ply model at the cord angle definition step, and the ply change at the time of internal pressure filling after vulcanization at the extension step. Therefore, according to the present invention, a tire model capable of more accurately reproducing the cross-sectional shape of the inflated pneumatic tire can be created from the cross-sectional shape of the mold. This is useful for accurate tire performance analysis.

It is a perspective view of the computer apparatus for performing the process of this embodiment. It is a flowchart which shows the creation method of this embodiment. It is sectional drawing of the pneumatic tire used by this embodiment. FIG. 4 is a development view showing the internal structure of the tire of FIG. 3. It is a top view of one belt cord. It is sectional drawing in the middle of vulcanization | cure of the pneumatic tire used by this embodiment. It is a perspective view which visualizes and shows a tire model. (A) is a partial perspective view of a carcass ply, (B) is a partial perspective view of the carcass ply model. (A) is a partial perspective view of a belt layer, (B) is a partial perspective view of the belt layer model. (A) is a partial plan view of the belt ply model, and (B) is a partial plan view of the belt ply model after the code angle defining step is executed on it. It is a partial top view of the belt ply model after an expansion | extension step is performed. It is sectional drawing of the expansion state of the tire model of an Example. It is sectional drawing of the expansion state of the tire model of a comparative example.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The present invention provides a method for creating a tire model used when analyzing (simulating) the performance of a pneumatic tire using a computer.

  The above analysis includes various numerical analysis methods such as a finite element method, a finite volume method, a difference method, or a boundary element method. Typical analysis using a tire model includes, for example, an internal pressure filling simulation in which an internal pressure condition is given to the tire model to perform deformation calculation, a ground shape simulation in which the tire model is pressed against the road surface model to examine the ground shape of the tread portion, For example, a rolling simulation in which the tire model is rolled on a road surface model.

  The present invention is a method for making a tire model of a pneumatic tire that is reinforced with a ply that is a layer of at least one cord and that is made through vulcanization molding in a mold. ADVANTAGE OF THE INVENTION According to this invention, the tire model which can reproduce accurately both the deformation | transformation of the ply during the vulcanization molding of a pneumatic tire and the deformation | transformation of the ply accompanying internal pressure filling can be created. Therefore, the tire model obtained by the present invention can more accurately reproduce the cross-sectional shape of the inflated pneumatic tire from the cross-sectional shape of the mold. Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to such specific embodiments.

  FIG. 1 shows a computer apparatus 1 on which the creation method of the present invention is executed.

  The computer device 1 includes a main body 1a, a keyboard 1b, a mouse 1c, and a display device 1d. The main body 1a is provided with a processing unit (CPU), a ROM, a working memory, a storage device such as a magnetic disk, and disk drive devices 1a1, 1a2. The storage device stores a processing procedure (program) for executing the creation method of the present embodiment in advance. The display device 1d can display the tire model created in the present embodiment.

  FIG. 2 shows an example of a processing procedure of the tire model creation method of the present embodiment.

  In the present embodiment, first, a tire model is created based on the cross-sectional shape of a two-dimensional mold for vulcanizing a pneumatic tire (step S1).

  FIG. 3 shows a cross-sectional view of the pneumatic tire 2 used in the present embodiment. As shown in FIG. 3, the pneumatic tire 2 has a tread portion 2a, a sidewall portion 2b, and a bead portion 2c. In the present embodiment, there is shown a motorcycle in which the outer surface of the tread portion 2a is greatly curved in a convex arc shape outward in the tire radial direction. However, the present invention can be applied to all categories of tires.

  The pneumatic tire 2 is reinforced with a ply that is a layer of at least one cord. In the present embodiment, the carcass 6 and the belt layer 7 are included as plies.

  The carcass 6 extends in a toroid shape so as to straddle between the bead portions 2c and 2c on both sides. The carcass 6 is composed of at least one carcass ply 6A, in this embodiment, one carcass ply 6A.

  The belt layer 7 is disposed outside the carcass 6 and inside the tread portion 2a. For example, the belt layer 7 includes two belt plies 7A and 7B stacked in the tire radial direction.

  FIG. 4 shows a developed view of the carcass 6 and the belt layer 7.

  As shown in FIG. 4, the carcass ply 6A includes a carcass cord 6c arranged at an angle of, for example, 70 to 90 degrees with respect to the tire equator C, and a topping rubber 6r that covers these.

  Each belt ply 7A, 7B includes a belt cord 7c that is inclined with respect to the tire circumferential direction and a topping rubber 7r that covers them. For these belt cords, non-extensible or highly elastic materials are used, and typically steel cords or aramids are employed. The belt cord 7c is covered with a topping rubber 7r for each ply. The belt plies 7A and 7B are overlapped so that the belt cords 7c and 7c intersect each other.

  4 and 5, the angle of the belt ply 7A, 7B of the belt layer 7 with respect to the tire circumferential direction of the belt cord 7c is determined based on the curvature of the belt plies 7A, 7B (the tire equator). The angle θs on the tread end side is larger than the angle θc on the C) side. That is, the belt cord meanders in a substantially S shape in a developed view. Further, although the carcass cord 6c is not as large as the belt cord 7c, it is meandering in an S-shape as a whole. The angle of the belt cord is determined in a range of about 5 to 80 degrees, for example.

  FIG. 6 is a cross-sectional view of the pneumatic tire 2 during vulcanization molding. As FIG. 6 shows, the metal mold | die 3 is comprised by the split mold | die 3A, 3B which can be divided | segmented into right and left, for example. The mold 3 has a cavity i inside, and the inner surface of the mold defining the cavity i constitutes a molding surface 3 a for molding the outer surface of the pneumatic tire 2. The pneumatic tire 2 is manufactured by vulcanizing a raw cover (not shown) mainly made of an unvulcanized rubber material and a ply material with the mold 3.

  At the time of vulcanization molding, the rubber material of the raw cover is plasticized by receiving heat, and is pressed from the inside to the molding surface 3a side by a balloon-like bladder B. Thereby, the outer surface of a raw cover contacts the molding surface 3a, and is shape | molded in the shape. At the same time, the ply material inside the raw cover is expanded and deformed by the pressure of the bladder. This will be described in more detail later.

  FIG. 7 shows a cross-sectional view of the tire model 4 created based on the cross-sectional shape of the mold 3. The tire model 4 is obtained by discretizing (modeling) the pneumatic tire 2 (shown in FIGS. 3 and 5) using a finite number of small elements 4a. Each element 4a has, for example, a rectangular shape, and a Lagrangian element is used in the present embodiment. The tire model 4 is a collection of numerical data stored in the computer device 1. Specifically, in the tire model 4, a node coordinate value, an element number, and a node number are defined for each element 4a. The tire model 4 of the present embodiment is created as a three-dimensional model in which the cross-sectional shape of FIG. 7 is developed in the tire circumferential direction.

  The contour shape of the outer surface of the tire model 4 obtained in step S <b> 1 substantially matches the contour shape of the molding surface 3 a of the mold 3. Since the sides of each element 4a of the tire model 4 are straight lines, the contour shape thereof does not completely coincide with the molding surface 3a of the mold 3 having a smooth surface, but at least the tread portion and sidewall of the tire model 4 The nodes appearing on the outer surface of the part and the bead part are preferably provided on the contour line of the molding surface 3 a of the mold 3.

  The tire model 4 includes, for example, a rubber model 8 and a ply model 9.

  The rubber model 8 is a model in which main rubber parts such as tread rubber and sidewall rubber are modeled by a finite number of elements. As the element 4a of the rubber model 8, for example, a three-dimensional solid element is used. For example, a tetrahedron, a pentahedron, or a hexahedron may be used as the solid element.

  The ply model 9 is obtained by modeling a ply with a finite number of elements, for example. The ply model 9 includes a carcass ply model 10 in which the carcass ply 6A is modeled, and a belt layer model 11 in which the belt layer 7 is modeled. The belt layer model 11 includes inner and outer belt ply models 11A and 11B. In FIG. 6, these ply models 9 are lightly colored so that they can be easily identified.

  FIG. 8A shows a partial perspective view of the carcass ply 6A, and FIG. 8B shows a perspective view of the carcass ply model 10 at that portion. The carcass ply 6A shown in FIG. 8A includes, for example, a membrane element 10a corresponding to the array of carcass cords 6c... And a solid element 10b corresponding to the topping rubber 6r as shown in FIG. And is modeled using The carcass ply model 10 of this embodiment has a laminated structure in which solid elements 9b are arranged on both sides of a membrane element 10a.

  FIG. 9A shows a partial perspective view of the belt layer 7, and FIG. 9B shows a perspective view of the belt layer model 11 at that portion. The laminated body of belt plies 7A and 7B shown in FIG. 9A includes, for example, membrane elements 11a and 11a corresponding to an array of belt cords 7c and a topping rubber 7r as shown in FIG. 9B. Are modeled into belt ply models 11A and 11B modeled using solid elements 11b corresponding to. In the present embodiment, solid elements 11b are arranged on both sides of the membrane element 11a.

  Next, in this embodiment, material physical properties and the like are defined for each element of the tire model (step S2 in FIG. 2). This process is performed, for example, by an input operation by an operator. Examples of material physical properties defined for each element include density, Young's modulus, and / or attenuation coefficient. Furthermore, superelasticity that does not cause a volume change is defined for each element of the rubber model. For example, the diameter, density, Young's modulus, and the like of the cord 6c or 7c corresponding to the membrane element 10a, 11a of the ply model 9 are defined.

  Next, in the present embodiment, a code angle defining step for defining the inclination angle θ of the cord of the ply model 9 is performed based on the expansion change of the ply during vulcanization molding (step S3 in FIG. 2).

  FIG. 9B shows a plan view of the membrane element 11a of the belt ply model 11B. Reference numeral 30 indicates a pseudo code (carcass cord 6c, belt cord 7c) defined for the membrane element, and the membrane element 11a does not actually have such a code. The membrane elements 10a and 11a in which such inclination angles are defined are not easily deformed in the longitudinal direction of the code component 30 by the code component 30 in the deformation calculation, and are deformed in a direction perpendicular to the longitudinal direction of the code component 30. It is possible to express the orthogonal anisotropy that is easy.

FIG. 10 (A) shows a schematic partial plan view of the belt layer model 11 as a state before vulcanization for reference, and FIG. 10 (B) shows a schematic partial plan view after the vulcanization. ing. The inclination angle of the cord component 30 of the membrane element 11a of the belt layer model 11 after vulcanization is indicated by “Φ” in order to distinguish it from FIG. In a preferred embodiment, the chord angle defining step S3 is performed only on the belt layer model 11.

  During vulcanization molding, the ply is expanded outward toward the molding surface 3a of the mold. In particular, the belt layer 7 has a large degree of expansion. On the other hand, the belt cord 7c of the belt layer 7 is usually made of a cord material whose elongation is extremely small. For this reason, during the vulcanization molding, the belt cord 7c is deformed so as to increase the outer diameter while changing the inclination angle θ of the belt cord with respect to the tire circumferential direction to be small. In the present embodiment, in order to obtain a tire model 4 having a more accurate shape, a cord angle defining step S3 is performed in which the angle change of the belt cord 7c during such vulcanization molding is given to the ply model 10.

ここで
ｘ：タイヤ赤道からのタイヤ軸方向距離（mm）
Ｄ（ｘ）：加硫金型内でのベルトプライの外径（mm）
Ｄ（０）：加硫金型内でのタイヤ赤道でのベルトプライの外径（mm）
ｄ：加硫金型投入前の生カバーのベルトプライの外径（mm）
θ：加硫金型投入前の生カバーのベルトコードのタイヤ周方向に対する角度（度）
α１〜α３：定数 Various methods are conceivable for realizing the code angle defining step S3. For example, the cord component 30 of the membrane elements 10a and 11a can be determined according to the extension (stretch) of the outer shape that the raw cover receives during vulcanization. In this case, it may be the same angle over the entire width of the belt ply, or may be changed in the tire width direction. As an example, the method described in Patent Document 1 can be adopted. In this method, the inclination angle φ (x) of the cord component 30 of the belt layer model 11 at the tire axial distance x from the tire equator C with respect to the tire circumferential direction is defined by the following equation (1).

Where x: tire axial distance from tire equator (mm)
D (x): Belt ply outer diameter in vulcanization mold (mm)
D (0): Belt ply outer diameter at the tire equator in the vulcanization mold (mm)
d: Outside cover belt ply outer diameter (mm) before vulcanization mold
θ: Angle (degrees) of the belt cord of the raw cover before the vulcanizing mold is inserted with respect to the tire circumferential direction
α1-α3: Constant

  The cos θ in the formula (1) indicates the length of the belt cord of the raw cover in the tire circumferential direction when the length of the belt cord 7c in the longitudinal direction is 1. D (x) / d indicates a stretch (expansion ratio) of the outer diameter of the belt plies 7A and 7B at the time of vulcanization molding. The constants α2 and α3 of the diameter D (x) are set based on the molding surface 3a of the tread portion of the mold 3.

  By multiplying the circumferential length cosθ of the belt cord 7c at the raw cover by the expansion ratio D (x) / d of the belt plies 7A and 7B, the length of the belt cord 7c in the tire circumferential direction after vulcanization molding is obtained. Is required. The angle φ (x) is obtained by multiplying the circumferential length cos θ × D (x) / d by the length cosine (1) of the belt cord 7c and further multiplying by a constant α1.

  The constant α1 is set to correct an error caused by a tire molding method or a rubber flow during vulcanization molding. This constant α1 is appropriately determined depending on the molding method and the type of rubber member. Specifically, at least three or more calculated values x and measured values y obtained under the same conditions are plotted on a scatter diagram in which the calculated value obtained by the above formula (1) is the x axis and the actually measured value is the y axis. The constant α1 can be obtained from the slope of the approximate straight line of the distribution.

  Furthermore, although the said patent document 1 describes the other numerical formula which calculates | requires the said angle (phi) (x), any of these may be employ | adopted.

  Next, in this embodiment, an extension step (step S4 in FIG. 2) for extending the ply model 9 is performed. FIG. 11 shows one membrane element 11a of the belt layer model 11 as the ply model 9. The virtual line is before the execution of the expansion step S4, and the solid line is after the execution of the expansion step S4. That is, the length of the membrane element 11a in the tire circumferential direction and the length in the width direction are increased.

  In FIG. 5, the belt cord meandering in an S-shape as indicated by a virtual line approaches a straight line as indicated by the solid line when the tire is inflated and deformed, and the tire is more likely to swell. In the present embodiment, such ease of inflation of the tire can be reproduced by extending the ply model 9, and can be approximated by a cross-sectional shape of an actual pneumatic tire when it is inflated.

  In a preferred embodiment, the ply model 9 is stretched several percent in the stretching step S4. The increase rate {(La-L) / L} in the tire circumferential direction and the increase rate {(Wa-W) / W} in the tire width direction are empirically based on the degree of meandering of the belt cord 7c. In the case of a motorcycle tire as in the present embodiment, about 0.01% to 1% is preferable. In the case of a passenger car tire, the increase rate is preferably about 0.005 to 0.5%. Furthermore, in a preferred embodiment, it is desirable that the increase rate in the tire circumferential direction and the increase rate in the tire width direction are the same.

  If the tire model is a two-dimensional model, it does not have a length in the tire circumferential direction in the first place, so it goes without saying that the extension step S4 extends only the length in the width direction of the belt ply model.

  As described above, in the method of the present invention, the change in the ply during vulcanization molding is given to the ply model in the code angle definition step S3, and the change in the ply during the internal pressure filling after vulcanization is given to the ply model in the expansion step S4. It is done. Therefore, according to the present invention, a tire model capable of more accurately reproducing the cross-sectional shape of the inflated pneumatic tire can be created from the cross-sectional shape of the mold. This is useful for accurate tire performance analysis.

  Next, the present embodiment further includes a step of calculating expansion deformation of the tire model 4 based on predetermined rim assembly conditions and internal pressure conditions (step S5 in FIG. 2). This step S5 is performed according to the custom. For example, the rim width of the tire model 4 is constrained to the defined rim width, and an evenly distributed load corresponding to the internal pressure is defined on the inner cavity surface of the tire model 4 for calculation. Thereby, the cross-sectional shape of the tire model 4 when the rim is assembled and the internal pressure is filled is obtained.

In FIG. 12, the cross-sectional shape of the tire model 4 obtained by the method of the present embodiment at the time of expansion is shown by an imaginary line (Example). The solid line shows the cross-sectional shape of the actual pneumatic tire 2 made with the mold 3 referred to in making the tire model 4 when inflated. The main specifications of this pneumatic tire 2 are as follows.
Size: 120 / 70ZR
Rim: 17 × 3.5MT
Internal pressure: 250 kPa
Belt cord angle: 75 degrees at the center and 78 degrees at the shoulder

  The tire model 4 was created using the cross-sectional shape of the mold 3 and a rubber gauge actually measured from the pneumatic tire 2. The anisotropic strong axis direction (direction along the cord component 30) of the membrane elements of the belt ply models 11A and 11B of the tire model 4 is 75 degrees at the center portion and the shoulder portion as in the case of the actual pneumatic tire 2. Was set to 78 degrees. In the extension step, the increase rate of the belt ply model was set to 0.3% in both the tire circumferential direction and the width direction.

  In FIG. 13, the cross-sectional shape of the tire model 4 obtained by the conventional method at the time of expansion is shown by imaginary lines (comparative example). The basic mold 3 is the same as the above example. The solid line shows the cross-sectional shape of the actual pneumatic tire 2 made of the mold 3 when inflated.

  Table 1 shows an error between the example and the comparative example and the actual tire regarding the outer diameter, the total width, and the tread radius.

  As is apparent from FIGS. 12 and 13 and Table 1, it can be confirmed that the tire model 4 of the example is very close to the cross-sectional shape of an actual pneumatic tire. On the other hand, it can be confirmed that the tire model 4 of the comparative example is smaller than the actual outer diameter of the tire and is considerably larger in the total width, and there is room for improvement in accuracy.

  As described above, various simulations are performed using the tire model 4 in which the cross-sectional shape is accurately reproduced (step S6 in FIG. 2). Needless to say, the simulation results can be obtained with higher accuracy than in the prior art.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

DESCRIPTION OF SYMBOLS 1 Computer apparatus 2 Pneumatic tire 3 Mold 4 Tire model 7 Belt layer 7A, 7B Belt ply 7c Belt cord 9 Ply model 10 Carcass ply model 11 Belt layer model

Claims (4)

About a pneumatic tire reinforced with a ply which is a layer of at least one cord and made through vulcanization molding in a mold,
A method for making a tire model for analyzing its performance using a computer,
Creating a tire model including a ply model obtained by modeling the ply with a finite number of elements based on a cross-sectional shape of the mold;
Defining a material property value according to the pneumatic tire for each element of the tire model;
A code angle defining step for defining an inclination angle of a cord of the ply model based on an expansion change of the ply during the vulcanization molding;
Viewing including the extension step of stretching the ply model,
In the stretching step, when the tire model is a two-dimensional model, the length in the width direction of the ply model is stretched . About a pneumatic tire reinforced with a ply which is a layer of at least one cord and made through vulcanization molding in a mold,
A method for making a tire model for analyzing its performance using a computer,
Creating a tire model including a ply model obtained by modeling the ply with a finite number of elements based on a cross-sectional shape of the mold;
Defining a material property value according to the pneumatic tire for each element of the tire model;
A code angle defining step for defining an inclination angle of a cord of the ply model based on an expansion change of the ply during the vulcanization molding;
Extending the ply model, and
In the stretching step, when the tire model is a three-dimensional model, the tire models in the tire circumferential direction and the width direction are stretched . 3. The method according to claim 1, further comprising a step of calculating expansion deformation of the tire model based on predetermined rim assembly conditions and internal pressure conditions after the code angle defining step and the extension step are executed . How to create a tire model. The ply model includes a belt layer model that models a belt layer including a belt ply arranged in a tread portion,
The tire model creation method according to any one of claims 1 to 3, wherein the cord angle definition step and the extension step are performed on the belt layer model .

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