Creation method of tire model

Abstract

To provide a creation method of a tire model which can create in a short time a numerical analytic model of tread patterns including plural kinds of pattern constitution units.SOLUTION: A creation method of a tire model is a method creating a numerical analytic model of tread patterns including at least plural kinds of pattern constitutional units whose lengths in a tire circumferential direction are different from each other. The creation method of a tire model comprises: a first step which inputs a basic pattern model 11 discretizing one kind of the plural kinds of pattern constitutional units through using a finite number of elements F(i); a second step which inputs a modified pattern model 21 discretizing other kinds of the plural kinds of pattern constitutional units in the finite number of elements F(i) through modifying the element F(i) of the basic pattern model 11 in the tire circumferential direction; and a third step in which a computer arrays the basic pattern model 11 and the modified pattern model 21 in the tire circumferential direction to create a tread pattern model.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for creating a tire model. [Background technology]

[0002] The following Patent Document 1 describes a method for creating a tire model for numerical analysis of a tire with a tread portion. In this method, the tire is modeled with a finite number of elements, and a tire model including a tread portion model corresponding to the tread portion is input. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-009482 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above method, the entire circumference of the tire tread pattern is discretized into a finite number of elements at once, so that, for example, when the tread pattern includes multiple types of pattern constituent units, these pattern constituent units can be faithfully reproduced. However, there is a problem that discretization using the elements takes a long time.

[0005] The present invention has been devised in consideration of the above-mentioned circumstances, and has as its main object to provide a method capable of creating, in a short period of time, a numerical analysis model of a tread pattern including multiple types of pattern constituent units. [Means for solving the problem]

[0006] The present invention is a method for creating a numerical analysis model of a tread pattern including at least multiple types of pattern constituent units having different lengths in the tire circumferential direction, the method including: a first step of inputting a basic pattern model in which one type of the multiple types of pattern constituent units is discretized using a finite number of elements into a computer; a second step of inputting a deformed pattern model in which another type of the multiple types of pattern constituent units is discretized using a finite number of elements by deforming the elements of the basic pattern model in the tire circumferential direction; and a third step of the computer arranging the basic pattern model and the deformed pattern model in the tire circumferential direction to create a tread pattern model. Effect of the Invention

[0007] By employing the above steps, the tire model creation method of the present invention makes it possible to create a numerical analysis model of a tread pattern including a plurality of types of pattern constituent units in a short period of time. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an example of a computer for executing a tire model creation method and a tire simulation method. [Diagram 2] FIG. 1 is a development view showing an example of a tread portion of a tire. [Diagram 3] 4 is a flowchart showing an example of a processing procedure of a tire model creating method. [Figure 4] FIG. 13A is a perspective view showing contour data of a third pattern constituent unit, and FIG. 13B is a perspective view showing a basic pattern model. [Diagram 5] FIG. 13A is a perspective view showing a basic pattern model and contour data of a fourth pattern constituent unit, and FIG. 13B is a cross-sectional view showing a fourth extended transformation model. [Figure 6] 13A is a perspective view of the fourth extended deformation model, and FIG. 13B is a perspective view of the fifth extended deformation model. [Figure 7]FIG. 1A is a perspective view of a first short deformed model, and FIG. 1B is a perspective view of a second short deformed model. [Figure 8] FIG. 2 is a perspective view showing an example of a tread pattern model. [Figure 9] FIG. 2 is a cross-sectional view showing an example of a tire model including a tread pattern model and a body model. [Figure 10] 1 is a flowchart showing an example of a processing procedure of a tire simulation method. [Figure 11] FIG. 2 is a perspective view showing an example of a tire model and a road surface model. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. It should be understood that the drawings include exaggerated expressions and expressions different from the dimensional ratio of the actual structure in order to help understand the contents of the invention. Furthermore, the same or common elements are given the same reference numerals throughout the embodiments, and duplicated explanations are omitted. Furthermore, the specific configurations shown in the embodiments and drawings are for understanding the contents of the present invention, and the present invention is not limited to the specific configurations shown in the drawings.

[0010] In the tire model creation method (hereinafter, sometimes referred to as the "creation method") of the present embodiment, a tire numerical analysis model (hereinafter, sometimes referred to as the "tire model") is created. This tire model can be used in a simulation method for predicting tire performance, for example.

[0011] [computer] 1 is a perspective view showing an example of a computer 1 for executing the tire model creation method and tire simulation method. The computer 1 includes a main body 1a, a keyboard 1b, a mouse 1c, and a display device 1d. The main body 1a is provided with, for example, a central processing unit (CPU), a ROM, a working memory, a storage device such as a magnetic disk, and disk drive devices 1a1 and 1a2. The storage device also stores in advance software for executing the creation method and simulation method of this embodiment.

[0012] [tire] Fig. 2 is a development view showing an example of a tread portion 2a of a tire 2. In Fig. 2, the circumferential grooves 3 and the lateral grooves 5 are colored.

[0013] Although the tire 2 of the present embodiment is exemplified as a pneumatic tire for a passenger vehicle, the tire 2 is not particularly limited. The tire 2 may be, for example, a tire for a heavy load such as a truck or a bus, or a tire for a two-wheeled vehicle. It is not important whether the tire 2 actually exists or not.

[0014] The tread portion 2a of this embodiment is provided with a plurality of circumferential grooves 3 extending continuously in the tire circumferential direction, and a plurality of land portions 4 separated by the plurality of circumferential grooves 3.

[0015] The circumferential grooves 3 of this embodiment include a pair of shoulder circumferential grooves 3A, 3A and a pair of center circumferential grooves 3B, 3B. The pair of shoulder circumferential grooves 3A, 3A extend continuously in the tire circumferential direction on the tread end 2t, 2t side. The pair of center circumferential grooves 3B, 3B extend continuously in the tire circumferential direction on the axially inner side of the pair of shoulder circumferential grooves 3A, 3A.

[0016] When the tire 2 is a pneumatic tire, the tread ends 2t, 2t are identified as the axially outermost contact points when the tire 2 is in a normal state, is loaded with a normal load, and is brought into contact with a flat surface with a camber angle of 0°.

[0017] The normal state refers to a state in which the tire 2 is mounted on a normal rim (not shown), inflated to normal internal pressure, and no load is applied. In this specification, unless otherwise specified, the dimensions of each part of the tire are indicated as values ​​measured in the normal state. Note that the dimensions are allowed for normal dimensional errors (tolerances) that are unavoidable during manufacturing.

[0018] A "genuine rim" is a rim that is determined for each tire by a standard system that includes the standard on which the tire 2 is based. Therefore, a genuine rim is, for example, a "standard rim" for JATMA, a "design rim" for TRA, and a "measuring rim" for ETRTO.

[0019] The "normal internal pressure" is the air pressure that is determined for each tire by each standard in a system of standards including the standard on which the tire 2 is based. Therefore, the normal internal pressure is, for example, the "maximum air pressure" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and the "INFLATION PRESSURE" in the case of ETRTO.

[0020] The "normal load" is the load that is determined for each tire by each standard in the standard system including the standard on which the tire 2 is based. Therefore, the normal load is, for example, "maximum load capacity" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and "LOAD CAPACITY" in the case of ETRTO.

[0021] The land portion 4 of this embodiment includes a pair of shoulder land portions 4A, 4A, a pair of middle land portions 4B, 4B, and a center land portion 4C. The pair of shoulder land portions 4A, 4A are formed between the shoulder circumferential groove 3A and the tread edge 2t. The pair of middle land portions 4B, 4B are formed between the center circumferential groove 3B and the shoulder circumferential groove 3A. The center land portion 4C is formed between the center circumferential grooves 3B, 3B.

[0022] In this embodiment, each land portion 4 is provided with, for example, a plurality of lateral grooves 5 and sipes 6. A tread pattern 7 is formed in the tread portion 2a by the circumferential grooves 3, the lateral grooves 5, the sipes 6, etc.

[0023] The tread pattern 7 includes at least multiple types of pattern constituent units 8. These pattern constituent units 8 are arranged in the tire circumferential direction to form the tread pattern 7. These pattern constituent units 8 (in this example, the first pattern constituent unit 8a to the fifth pattern constituent unit 8e) have mutually different lengths L1 (in this example, L1a to L1e) in the tire circumferential direction.

[0024] The number of types of pattern constituent units 8 is set appropriately depending on the vehicle on which the tire 2 is mounted and the driving conditions, and can be set to, for example, 2 to 10. In this embodiment, five types of pattern constituent units 8 are included, including a first pattern constituent unit 8a, a second pattern constituent unit 8b, a third pattern constituent unit 8c, a fourth pattern constituent unit 8d, and a fifth pattern constituent unit 8e. Of these pattern constituent units 8, the length L1a in the tire circumferential direction of the first pattern constituent unit 8a is set to the smallest, and the length L1e in the tire circumferential direction of the fifth pattern constituent unit 8e is set to the largest.

[0025] In the first pattern constituent unit 8a to the fifth pattern constituent unit 8e, the circumferential grooves 3, the lateral grooves 5, and the sipes 6 are formed to have substantially the same shapes. Here, "substantially the same" means that manufacturing errors are allowed. In the first pattern constituent unit 8a to the fifth pattern constituent unit 8e, the lateral grooves 5 and the sipes 6 may be set to the same positions in the tire circumferential direction, or may be different from each other.

[0026] [Tire model creation method (first embodiment)] Next, the processing procedure of the creation method of this embodiment will be described below with reference to Fig. 3. Fig. 3 is a flowchart showing an example of the processing procedure of the tire model creation method.

[0027] In the creation method of this embodiment, a numerical analysis model of the tread pattern 7 shown in FIG. 2 (hereinafter sometimes referred to as the "tread pattern model") is created as a tire model. Furthermore, in the creation method of this embodiment, a numerical analysis model (hereinafter sometimes referred to as the "body model") of a body portion (not shown) that is radially inward of the deepest portion in the tire radial direction of the circumferential grooves 3, lateral grooves 5, sipes 6, etc. that constitute the tread pattern 7 is created. The tire model is created by integrally connecting (defining) these tread pattern model and body model. Note that the tire model may be composed of only the tread pattern model, omitting the body model, depending on the purpose of the analysis, etc.

[0028] [Input a basic pattern model that discretizes one type of pattern unit (first step)] In the creation method of this embodiment, first, a basic pattern model in which one of the multiple types of pattern constituent units 8 shown in FIG. 2 is discretized using a finite number of elements is input into a computer 1 (shown in FIG. 1) (first step S1).

[0029] The pattern constituent units 8 to be discretized as the basic pattern model may be appropriately selected from multiple types of pattern constituent units 8. In this embodiment, the average value of the lengths L1 in the tire circumferential direction of the multiple types of pattern constituent units 8 is calculated, and the pattern constituent unit 8 having the length L1 closest to the average value is selected. If there are multiple pattern constituent units 8 having the length L1 closest to the average value, one of these pattern constituent units 8 may be selected. In this embodiment, the third pattern constituent unit 8c having the length L1c is selected.

[0030] In the first step S1 of this embodiment, first, contour data of one type (in this example, third pattern constituent unit 8c) among the multiple types of pattern constituent units 8 is input to computer 1 (shown in FIG. 1). FIG. 4(a) is a perspective view showing contour data 10 of third pattern constituent unit 8c. FIG. 4(b) is a perspective view showing basic pattern model 11.

[0031] As shown in Fig. 4(a), the contour data 10 of this embodiment includes a plurality of coordinate values ​​capable of specifying the contour shape of the three-dimensional third pattern unit 8c. The coordinate values ​​are set, for example, according to a Cartesian coordinate system (x-axis, y-axis, and z-axis coordinate values). For example, CAD data created at the design stage of the tire 2 shown in Fig. 2 is preferably used as the contour data 10.

[0032] The contour data 10 of this embodiment specifies the contours of the circumferential groove 3, the land portion 4, the lateral groove 5, and the sipes 6 provided in the third pattern constituent unit 8c. In this embodiment, the contour of the deepest part (groove bottom) of the circumferential groove 3 is omitted.

[0033] The contour of the circumferential groove 3 in this embodiment includes the contour of a pair of shoulder circumferential grooves 3A, 3A and the contour of a pair of center circumferential grooves 3B, 3B. The land portion 4 includes the contour of a pair of shoulder land portions 4A, 4A, the contour of a pair of middle land portions 4B, 4B, and the contour of a center land portion 4C.

[0034] Next, in the first step S1 of this embodiment, as shown in Fig. 4(b), the contour data 10 (shown in Fig. 4(a)) is discretized using a finite number of elements (meshes) F(i) (i = 1, 2, ...), thereby defining a basic pattern model 11.

[0035] The element F(i) can be handled by a numerical analysis method. Examples of the numerical analysis method include the finite element method, the finite volume method, the difference method, and the boundary element method. In this embodiment, the finite element method is adopted. Furthermore, as the element F(i), for example, a tetrahedral solid element, a pentahedral solid element, or a hexahedral solid element is used. In this embodiment, a hexahedral solid element is used.

[0036] An element F(i) has a plurality of nodes 12 and edges 13 connecting the nodes 12, 12. The edges 13 extend linearly. For each element F(i), numerical data such as an element number, the node 12 number, the coordinate values ​​of the nodes 12, and material properties (e.g., density, Young's modulus, and / or damping coefficient) are defined.

[0037] The basic pattern model 11 includes a circumferential groove model 14, a land model 15, a lateral groove model 16, and a sipe model 17. Of these models, the circumferential groove model 14, the lateral groove model 16, and the sipe model 17 are specified by the contour of the land model 15, and are not discretized by the element F(i).

[0038] The circumferential groove model 14 of this embodiment is a model of the circumferential groove 3 provided in one type (the third pattern constituent unit 8c in this example) of the multiple types of pattern constituent units 8 shown in FIG. 2. This circumferential groove model 14 includes a pair of shoulder circumferential groove models 14A, 14A and a pair of center circumferential groove models 14B, 14B. The pair of shoulder circumferential groove models 14A, 14A are models of the pair of shoulder circumferential grooves 3A, 3A shown in FIG. 4(a). The pair of center circumferential groove models 14B, 14B are models of the pair of center circumferential grooves 3B, 3B shown in FIG. 4(a).

[0039] As shown in FIG. 4(b), the land portion model 15 of this embodiment is a model of the land portion 4 provided in one type (the third pattern portion 8c in this example) of the multiple types of pattern portion units 8 shown in FIG. 2. This land portion model 15 includes a pair of shoulder land portion models 15A, 15A, a pair of middle land portion models 15B, 15B, and a center land portion model 15C. The pair of shoulder land portion models 15A, 15A are modeled respectively of the pair of shoulder land portions 4A, 4A shown in FIG. 4(a). The pair of middle land portion models 15B, 15B are modeled respectively of the pair of middle land portions 4B, 4B shown in FIG. 4(a). The center land portion model 15C is modeled respectively of the center land portion 4C shown in FIG. 4(a).

[0040] As shown in Fig. 4(b), the lateral groove model 16 of this embodiment is a model of the lateral groove 5 provided in one type (in this example, the third pattern unit 8c) of the multiple types of pattern units 8 shown in Fig. 2. The sipe model 17 of this embodiment is a model of the sipe 6 provided in one type (in this example, the third pattern unit 8c shown in Fig. 4(a)) of the multiple types of pattern units 8.

[0041] In this manner, the basic pattern model 11 of this embodiment includes the above-mentioned circumferential groove model 14, land model 15, lateral groove model 16, and sipe model 17. This allows for the definition of a basic pattern model 11 that faithfully reproduces one type (in this example, the third pattern constituent unit 8c) of the multiple types of pattern constituent units 8 shown in Fig. 2.

[0042] Both end faces 11a, 11b of the basic pattern model 11 in the tire circumferential direction are formed with connection faces 22 that are connected to adjacent basic pattern models 11 in the tire circumferential direction or to a deformed pattern model 21 described below.

[0043] Meshing software is used to define the basic pattern model 11. Examples of meshing software include "PointWise" by PointWise, Inc., "HyperMESH (registered trademark)" by Altea Engineering, Inc., and "FEMAP (registered trademark)" by Siemens PLM Software, Inc. The basic pattern model 11 is stored in a computer 1 (shown in FIG. 1).

[0044] [Input the deformed pattern model in which other types of pattern units are discretized (second step)] Next, in the creation method of this embodiment, a deformed pattern model in which the other types of the multiple types of pattern constituent units are discretized with a finite number of elements is input to the computer 1 (shown in FIG. 1) (second step S2). The deformed pattern model is defined by deforming the element F(i) of the basic pattern model 11 shown in FIG. 4(b) in the tire circumferential direction.

[0045] As described above, in this embodiment, the third pattern constituent unit 8c is selected as one type of pattern constituent unit 8 shown in Fig. 2. In this case, other types of pattern constituent units 8 include the first pattern constituent unit 8a, the second pattern constituent unit 8b, the fourth pattern constituent unit 8d, and the fifth pattern constituent unit 8e. Then, a deformed pattern model is defined by modeling each of these pattern constituent units 8.

[0046] The deformed pattern model of this embodiment includes at least one type of extended deformed model in which the basic pattern model 11 shown in Fig. 4(b) is stretched in the tire circumferential direction. In this embodiment, the third pattern constituent unit 8c shown in Fig. 2 is modeled as the basic pattern model 11. In this case, the fourth pattern constituent unit 8d and the fifth pattern constituent unit 8e, which have a longer length L1 in the tire circumferential direction than the third pattern constituent unit 8c, are modeled as extended deformed models. Therefore, the extended deformed models include a fourth extended deformed model modeled on the fourth pattern constituent unit 8d and a fifth extended deformed model modeled on the fifth pattern constituent unit 8e.

[0047] The deformed pattern model of this embodiment includes at least one type of reduced deformed model in which the basic pattern model 11 is reduced in the tire circumferential direction. In this embodiment, the third pattern constituent unit 8c shown in FIG. 2 is modeled as the basic pattern model 11. In this case, the first pattern constituent unit 8a and the second pattern constituent unit 8b, which have a shorter length L1 in the tire circumferential direction than the third pattern constituent unit 8c, are modeled as reduced deformed models. Therefore, the short deformed models include a first short deformed model modeled on the first pattern constituent unit 8a and a second short deformed model modeled on the second pattern constituent unit 8b.

[0048] In the second step S2 of this embodiment, first, a fourth extended deformation model is defined by modeling the fourth pattern constituent unit 8d shown in Fig. 2. Fig. 5(a) is a perspective view showing the basic pattern model 11 and the contour data 10 of the fourth pattern constituent unit 8d. Fig. 5(b) is a cross-sectional view showing the fourth extended deformation model 21D.

[0049] Fig. 5(a) shows one shoulder land model 15A (the shoulder land model on the left side in the figure) of a pair of shoulder land models 15A, 15A constituting the basic pattern model 11 shown in Fig. 4(b). Also, in Fig. 5(a), the contour data 10 of the fourth pattern constituent unit 8d is shown by a two-dot chain line.

[0050] In this embodiment, first, as shown in Fig. 5(a), the basic pattern model 11 used to define the fourth extended deformation model 21D (shown in Fig. 5(b)) is copied. Next, the contour data 10 (shown by a two-dot chain line) of the fourth pattern constituent unit 8d is input. At this time, one end face 11a of the basic pattern model 11 and one end face 10a of the contour data 10 of the fourth pattern constituent unit 8d are aligned in the tire circumferential direction.

[0051] Next, the node 12 (hereinafter sometimes referred to as the "fixed node 12A") disposed on one end face 11a of the basic pattern model 11 is fixed (constrained) so as not to move. In Fig. 5, the fixed node 12A is indicated by a white circle "○".

[0052] Next, a node 12 (hereinafter sometimes referred to as "selected node 12B") located on the other end face 11b of the basic pattern model 11 is selected. In Fig. 5, the selected node 12B is indicated by a black circle "●". In this embodiment, the relative position of the selected node 12B is constrained so that the shape of the element F(i) appearing on the other end face 11b of the basic pattern model 11 is maintained.

[0053] Next, all the nodes 12 except for the fixed nodes 12A are moved along the tire circumferential direction so that these selected nodes 12B are positioned on the other end face 10b (shown by a two-dot chain line) of the contour data 10 of the fourth pattern constituent unit 8d.

[0054] In this embodiment, the basic pattern model 11 is stretched in the tire circumferential direction by the above-mentioned movement of the node 12 in the tire circumferential direction, and a fourth extended deformation model 21D (shown in FIG. 5(b)) that matches the contour of the fourth pattern constituent unit 8d is defined. Such stretching can be easily performed, for example, by the function "morphing" provided in the above-mentioned meshing software.

[0055] However, if the above-mentioned node 12 is simply moved, the positions of the lateral groove model 16 and the sipe model 17 of the basic pattern model 11 after the movement may not match the positions of the lateral groove 5 and the sipe 6 provided in the fourth pattern constituent unit 8d (shown by a two-dot chain line in FIG. 5(a)). In this case, the movement of the node 12 may be fine-tuned so that the positions of the lateral groove model 16 and the sipe model 17 of the basic pattern model 11 after the movement match the positions of the lateral groove 5 and the sipe 6 provided in the fourth pattern constituent unit 8d. This allows the fourth extended deformation model 21D to be defined with high accuracy.

[0056] In this embodiment, prior to the movement of the node 12, the fixed node 12A of the basic pattern model 11 is fixed (constrained) so as to be immovable, and furthermore, the relative position of the selected node 12B of the basic pattern model 11 is constrained. As a result, the shapes of the element F(i) appearing on both one end face 21a of the fourth extended deformation model 21D and one end face 11a of the basic pattern model 11 (shown in FIG. 5(a)) match each other. Furthermore, the shapes of the element F(i) appearing on both the other end face 21b of the fourth extended deformation model 21D and the other end face 11b of the basic pattern model 11 (shown in FIG. 5(a)) match each other. These one end faces 21a, 11a and the other end faces 21b, 11b are configured as the connection faces 22 of the basic pattern model 11 and the deformation pattern model 21 (fourth extended deformation model 21D). Therefore, in the second step S2, the element F(i) of the basic pattern model 11 can be deformed so that the shapes of the element F(i) appearing on the connection surface 22 of the basic pattern model 11 and the connection surface 22 of the deformed pattern model 21 (fourth extended deformed model 21D) are identical to each other.

[0057] In this embodiment, in addition to one shoulder land model 15A of the fourth extended deformation model 21D, the other shoulder land model 15A, middle land models 15B, 15B, and center land model 15C of the fourth extended deformation model 21D are defined based on the above procedure. In this way, the fourth extended deformation model 21D is defined. Fig. 6(a) is a perspective view of the fourth extended deformation model 21D. The fourth extended deformation model 21D is stored in the computer 1 (shown in Fig. 1).

[0058] Next, in the second step S2 of this embodiment, a fifth extended deformation model is defined by modeling the fifth pattern constituent unit 8e shown in Fig. 2. Fig. 6(b) is a perspective view of the fifth extended deformation model 21E.

[0059] The fifth extended deformation model 21E is defined based on the same procedure as the fourth extended deformation model 21D shown in Figures 5(a) and (b). That is, all the nodes 12 except the fixed node 12A are moved along the tire circumferential direction so that the selected node 12B of the basic pattern model 11 is located on the other end face 10b (not shown) of the contour data 10 of the fifth pattern constituent unit 8e. This allows the definition of the fifth extended deformation model 21E whose contour matches that of the fifth pattern constituent unit 8e, as shown in Figure 6(b).

[0060] In this embodiment, prior to the movement of the node 12 described above, the fixed node 12A of the basic pattern model 11 shown in Fig. 5(a) is fixed (constrained) so as to be immovable, and further, the relative position of the selected node 12B of the basic pattern model 11 is constrained. As a result, in the second step S2, the element F(i) of the basic pattern model 11 can be deformed so that the shapes of the elements F(i) appearing on the connection surface 22 of the basic pattern model 11 and the connection surface 22 of the deformed pattern model 21 (fifth extended deformation model 21E) are identical to each other. The fifth extended deformation model 21E is stored in the computer 1 (shown in Fig. 1).

[0061] Next, in the second step S2 of this embodiment, a first short and deformed model is defined by modeling the first pattern constituent unit 8a shown in Fig. 2. Fig. 7(a) is a perspective view of the first short and deformed model 21A.

[0062] In this embodiment, first, as shown in Fig. 5(a), the basic pattern model 11 used to define the first short and small deformed model 21A is copied, and the contour data 10 (not shown) of the first pattern constituent unit 8a shown in Fig. 2 is input to the computer 1 (shown in Fig. 1). At this time, one end face 11a of the basic pattern model 11 and one end face 10a (not shown) of the contour data 10 of the first pattern constituent unit 8a are aligned in the tire circumferential direction.

[0063] Next, the fixed nodes 12A of the basic pattern model 11 are fixed so as to be immovable, and further, the selected nodes 12B of the basic pattern model 11 are specified. Then, all the nodes 12 except the fixed nodes 12A are moved along the tire circumferential direction so that these selected nodes 12B are positioned on the other end face 10b (not shown) of the contour data 10 of the first pattern constituent unit 8a.

[0064] In this embodiment, the basic pattern model 11 is shrunk in the tire circumferential direction by the above-mentioned movement of the node 12 along the tire circumferential direction, and a first short and small deformed model 21A (shown in FIG. 7(a)) whose outline matches the first pattern constituent unit 8a shown in FIG. 2 is defined. Note that if the positions of the lateral groove model 16 and the sipe model 17 of the basic pattern model 11 after the movement do not match the positions of the lateral groove 5 and the sipe 6 provided in the first pattern constituent unit 8a shown in FIG. 2, the movement of the node 12 may be fine-adjusted. This allows the first short and small deformed model 21A to be defined with high accuracy.

[0065] In this embodiment, prior to the movement of the above-mentioned node 12, the fixed node 12A of the basic pattern model 11 is fixed (constrained) so as to be immovable, and further, the relative position of the selected node 12B of the basic pattern model 11 is constrained. As a result, in the second step S2, the element F(i) of the basic pattern model 11 can be deformed so that the shapes of the elements F(i) appearing on the connection surface 22 of the basic pattern model 11 shown in Fig. 4(b) and the connection surface 22 of the first short and deformed model 21A shown in Fig. 7(a) become identical. The first short and deformed model 21A is stored in the computer 1 (shown in Fig. 1).

[0066] Next, in the second step S2 of this embodiment, a second short and deformed model is defined by modeling the second pattern constituent unit 8b shown in Fig. 2. Fig. 7(b) is a perspective view of the second short and deformed model 21B.

[0067] The second short deformed model 21B is defined based on the same procedure as the first short deformed model 21A. That is, all the nodes 12 except the fixed node 12A are moved along the tire circumferential direction so that the selected node 12B (shown in FIG. 5(a)) of the basic pattern model 11 is positioned on the other end face 10b (not shown) of the contour data 10 of the second pattern constituent unit 8b. This allows the definition of the second short deformed model 21B, whose contour matches that of the second pattern constituent unit 8b, as shown in FIG. 7(b).

[0068] In this embodiment, prior to the movement of the node 12 described above, the fixed node 12A of the basic pattern model 11 shown in Fig. 5(a) is fixed (constrained) so as to be immovable, and further, the relative position of the selected node 12B of the basic pattern model 11 is constrained. As a result, in the second step S2, the element F(i) of the basic pattern model 11 can be deformed so that the shapes of the elements F(i) appearing on the connection surface 22 of the basic pattern model 11 and the connection surface 22 of the deformed pattern model 21 (second short and small deformed model 21B) are identical to each other. The second short and small deformed model 21B is stored in the computer 1 (shown in Fig. 1).

[0069] In this way, in the second step S2, a deformed pattern model 21 (shown in FIGS. 6 and 7) that reproduces another type (such as the fourth pattern constituent unit 8d) of the multiple types of pattern constituent units 8 shown in FIG. 2 can be defined by deforming the element F(i) of the basic pattern model 11 shown in FIG. 5(a). For this reason, it is not necessary to collectively discretize the other types of the multiple types of pattern constituent units 8 using a finite number of elements F(i). Therefore, the time required for modeling the deformed pattern model 21 can be shortened.

[0070] In the second step S2 of this embodiment, the movement of the nodes 12 is finely adjusted so that the positions after the movement of the lateral groove model 16 and the sipe model 17 of the basic pattern model 11 coincide with the positions of the lateral grooves 5 and sipes 6 provided in the other types of the multiple types of pattern constituent units 8. As a result, in the second step S2 of this embodiment, a deformed pattern model 21 that faithfully reproduces the other types of the multiple types of pattern constituent units 8 can be defined.

[0071] In the second step S2, the elements F(i) of the basic pattern model 11 can be deformed so that the shapes of the elements F(i) appearing on the connection surface 22 of the basic pattern model 11 (shown in FIG. 4(b)) and the connection surface 22 of the deformed pattern model 21 (shown in FIGS. 6 and 7) are identical. This makes it possible to match the positions of the nodes 12 of the basic pattern model 11 appearing on the connection surface 22 with the positions of the nodes 12 of the deformed pattern model 21 in a third step S3 described below, so that these nodes 12 can be easily shared.

[0072] [Create tread pattern model (third step)] Next, in the creation method of this embodiment, the computer 1 (shown in FIG. 1) arranges the basic pattern model 11 and the deformed pattern model 21 in the tire circumferential direction to create a tread pattern model (third step S3). FIG. 8 is a perspective view showing an example of the tread pattern model 23.

[0073] First, in the third step S3, the basic pattern model 11 shown in FIG. 4(b) and the deformed pattern models 21 (the first short and small deformed model 21A, the second short and small deformed model 21B, the fourth extended deformed model 21D, and the fifth extended deformed model 21E) shown in FIG. 6 and FIG. 7 are arranged in the tire circumferential direction. The basic pattern model 11 and the deformed pattern model 21 may be arranged as appropriate. In this embodiment, the basic pattern model 11 and the deformed pattern model 21 may be arranged in the tire circumferential direction based on a tire circumferential direction arrangement table (not shown) of the pattern constituent units 8 specified in the design stage of the tire 2 shown in FIG. 2.

[0074] In the third step S3 of the present embodiment, the basic pattern model 11 and the deformed pattern model 21 are arranged based on the above-mentioned arrangement table, but the arrangement is not limited to this. For example, the basic pattern model 11 and the deformed pattern model 21 may be arranged in the tire circumferential direction based on the judgment of an operator performing the third step S3.

[0075] As shown in Figure 8, in the third process S3, the basic pattern model 11 and the deformed pattern model 21 are arranged in the tire circumferential direction, so that the connection surfaces 22 (shown in Figures 4, 6 and 7) of the basic pattern model 11 and the deformed pattern model 21 adjacent to each other in the tire circumferential direction can come into contact with each other.

[0076] Next, in a third step S3 of this embodiment, the basic pattern model 11 and the deformed pattern model 21 are connected so that the nodes 12 of the basic pattern model 11 and the nodes 12 of the deformed pattern model 21 appearing on the connection surface 22 are shared with each other. As described above, the shapes of the elements F(i) appearing on these connection surfaces 22 are the same, and therefore the positions of the nodes 12 appearing on these connection surfaces 22 are also the same. Therefore, for example, even without remeshing the basic pattern model 11 and the deformed pattern model 21, the nodes 12 of the basic pattern model 11 and the deformed pattern model 21 appearing on the connection surface 22 can be easily shared. Such sharing of the nodes 12 can be easily performed, for example, by the above-mentioned meshing software.

[0077] In the third step S3 of this embodiment, the nodes 12 appearing on the connection surfaces 22 of the basic pattern model 11 and the deformed pattern model 21 are supplied to each other, thereby creating a tread pattern model 23 in which the basic pattern model 11 and the deformed pattern model 21 are connected as a single unit.

[0078] In the third step S3 of this embodiment, the basic pattern model 11 and the deformed pattern model 21 are arranged around the entire circumference of the tire in the circumferential direction. The basic pattern model 11 and the deformed pattern model 21 are connected together to create an annular tread pattern model 23. In this embodiment, the basic pattern model 11, the first short and small deformed model 21A, the second short and small deformed model 21B, the fourth extended deformed model 21D, and the fifth extended deformed model 21E are arranged, but are not limited to this. For example, some of these models may be omitted, or other models may be further added.

[0079] In this embodiment, the deformed pattern model 21 shown in Fig. 6 and Fig. 7 is defined by deforming the element F(i) of the basic pattern model 11 shown in Fig. 4(b) in the tire circumferential direction. This makes it possible to define a tread pattern model 23 (shown in Fig. 8) that reproduces the tread pattern 7 including a plurality of pattern constituent units 8, without discretizing the entire circumference of the tread pattern 7 of the tire 2 shown in Fig. 2 collectively with a finite number of elements. Therefore, the creation method of this embodiment makes it possible to create a tread pattern model 23 including a plurality of types of pattern constituent units 8 (basic pattern model 11 and deformed pattern model 21) in a short time.

[0080] In this embodiment, the deformed pattern model 21 is created by deforming the elements F(i) of the basic pattern model 11 so that the shapes of the elements F(i) appearing on the connection surface 22 of the basic pattern model 11 and the deformed pattern model 21 are identical. This allows the nodes 12 of the basic pattern model 11 and the deformed pattern model 21 appearing on the connection surface 22 to be easily shared, for example, without remeshing the basic pattern model 11 and the deformed pattern model 21. This makes it possible to create the tread pattern model 23 in a short period of time.

[0081] In this embodiment, the deformed pattern models 21 include extended deformed models 31 (fourth extended deformed model 21D and fifth extended deformed model 21E) in which the basic pattern model 11 is stretched in the tire circumferential direction. Furthermore, in this embodiment, the deformed pattern models 21 include short deformed models 32 (first short deformed model 21A and second short deformed model 21B) in which the basic pattern model 11 is shrunk in the tire circumferential direction.

[0082] In this way, since the deformed pattern model 21 of this embodiment includes the extended deformed model 31 and the short deformed model 32, the element F(i) is prevented from becoming unnecessarily large, as compared to when the deformed pattern model 21 is composed of, for example, only the extended deformed model 31. Furthermore, compared to when the deformed pattern model 21 is composed of, for example, only the short deformed model 32, the element F(i) is prevented from becoming unnecessarily small. Therefore, the difference in size of the element F(i) between the basic pattern model 11 and the deformed pattern model 21 is prevented from becoming large, preventing a decrease in simulation accuracy. The tread pattern model 23 is stored in the computer 1 (shown in FIG. 1).

[0083] [Enter body model] Next, in the creation method of this embodiment, a body model obtained by modeling a body portion (not shown) of the tire 2 shown in Fig. 2 is input to the computer 1 shown in Fig. 1 (step S4). Fig. 9 is a cross-sectional view showing an example of a tire model 25 including a tread pattern model 23 and a body model 24.

[0084] In step S4 of this embodiment, first, contour data (not shown) of the body portion of the tire 2 is input to a computer (shown in FIG. 1). As such contour data, it is preferable to use, for example, CAD data or the like created at the design stage of the tire 2.

[0085] Next, in step S4 of this embodiment, the contour data of the body part is discretized using a finite number of elements (meshes) G(i) (i=1, 2, ...). This defines the body model 24. The elements G(i) may be the same as the above-mentioned elements F(i).

[0086] The body model 24 includes a pair of sidewall portions 25b, 25b and a pair of bead portions 25c, 25c. The body model 24 of this embodiment may include elements that resemble fiber reinforcement materials such as a carcass and a belt ply. The body model 24 is stored in the computer 1 shown in FIG.

[0087] [Enter tire model] Next, in the creation method of this embodiment, a tire model 25 including a tread pattern model 23 and a body model 24 is input to the computer 1 shown in FIG. 1 (step S5). In step S5 of this embodiment, first, the body model 24 is disposed on the tire radially inner side of the tread pattern model 23. Then, in the contact surface (not shown) between the tread pattern model 23 and the body model 24, the relative positions in the tire circumferential direction are constrained between the node 12 of the tread pattern model 23 and the node 29 of the body model 24. This allows the tire model 25 in which the tread pattern model 23 and the body model 24 are fixed together to be created. The tire model 25 is stored in the computer 1 (shown in FIG. 1).

[0088] [Tire model creation method (second embodiment)] In the creation methods of the above-described embodiments, an annular tread pattern model 23 is created as shown in Fig. 8, but the present invention is not limited to this. For example, a fragmentary tread pattern model (not shown) that models a portion of the tread pattern 7 in the tire circumferential direction may be created.

[0089] In the third step S3 of this embodiment, a basic pattern model 11 (shown in FIG. 4(b)) and a deformed pattern model 21 (shown in FIGS. 6 and 7) are arranged on a partial region in the tire circumferential direction. The basic pattern model 11 and the deformed pattern model 21 are connected together to create a fragmentary tread pattern model (not shown). Such a fragmentary tread pattern model minimizes the number of nodes 12 that need to be shared at the connection surfaces 22 shown in FIGS. 4(b), 6 and 7, so that the tread pattern model can be created in a shorter time.

[0090] [Tire model creation method (third embodiment)] In the above embodiments, one type of basic pattern model 11 (shown in FIG. 4(b)) is created, and the element F(i) of this basic pattern model 11 is transformed to define the deformed pattern model 21 shown in FIG. 6 and FIG. 7, but the present invention is not limited to such an embodiment. For example, one type of basic pattern model 11 and another type of basic pattern model 11 (not shown) may be created, and the element F(i) of these multiple types of basic pattern models 11 may be transformed to define the deformed pattern model 21 shown in FIG. 6 and FIG. 7. This makes it possible to create a tread pattern model 23 (shown in FIG. 8) that flexibly corresponds to the positions of the lateral grooves 5 and sipes 6 provided in the pattern constituent units 8 shown in FIG. 2.

[0091] [Tire simulation method] Next, a tire simulation method will be described below. In the simulation method of this embodiment, Fig. 10 is a flowchart showing an example of a processing procedure of the tire simulation method.

[0092] [Enter tire model] In the simulation method of this embodiment, first, a tire model 25 is input to the computer 1 shown in Fig. 1 (step S11). In step S11 of this embodiment, the tire model 25 shown in Fig. 9 is set based on the processing procedure shown in Fig. 3. Note that in step S11, a tread pattern model 23 (shown in Fig. 8) in which the body model 24 is omitted from the tire model 25 may be used as the tire model. The tire model 25 is input to the computer 1 (shown in Fig. 1).

[0093] [Road surface model] Next, in the simulation method of this embodiment, the road surface model is input to the computer 1 shown in Fig. 1 (step S12). Fig. 11 is a perspective view showing an example of a tire model 25 and a road surface model 27. In Fig. 11, the tread pattern of the tire model 25 is omitted.

[0094] In step S12 of this embodiment, based on information about the road surface (not shown), the road surface is discretized using a finite number of elements H(i) (i=1, 2, ...) that can be handled by a numerical analysis method (in this embodiment, the finite element method). As a result, in step S12, a road surface model 27 can be set.

[0095] Element H(i) is defined as a rigid plane element that is defined to be undeformable. Element H(i) has a plurality of nodes 30. Furthermore, element H(i) is defined with numerical data such as an element number and the coordinate values ​​of the nodes 30.

[0096] In this embodiment, a road surface model 27 having a smooth surface is defined, but is not limited to this. For example, a road surface model 27 (not shown) may be defined that has minute irregularities, irregular steps, depressions, undulations, or irregularities such as ruts that resemble the actual road surface. The road surface model 27 is stored in the computer 1 (shown in FIG. 1).

[0097] [Calculate tire model after internal pressure filling] Next, in the simulation method of this embodiment, the computer 1 (shown in FIG. 1) calculates the tire model 25 after internal pressure filling (step S13). In step S13, first, as shown in FIG. 9, fitting of the rim model 28 to the tire model 25 is calculated so as to constrain the bead portions 25c, 25c of the tire model 25. The rim model 28 is a model of a rim (not shown) to which the tire 2 shown in FIG. 2 is assembled. Furthermore, in step S13, deformation of the tire model 25 is calculated based on a uniformly distributed load w equivalent to the internal pressure (internal pressure condition). As a result, in step S13, the tire model 25 after internal pressure filling is calculated. The tire model 25 after internal pressure filling is stored in the computer 1 (shown in FIG. 1).

[0098] For deformation calculation of the tire model 25, a mass matrix, a stiffness matrix, and a damping matrix are created for each element F(i) and G(i) based on the shape and material properties of each element. Furthermore, these matrices are combined to create a matrix for the entire system. Then, the computer 1 creates equations of motion by applying the various conditions described above, and performs deformation calculation of the tire model 25 using these equations for each unit time T(x) (x=0, 1, ...) (for example, every 1 μsec). For such deformation calculation, commercially available finite element analysis application software such as LS-DYNA, Abaqus, ANSYS, or Dytran manufactured by LSTC is used.

[0099] [Calculate the physical quantities of the tire model] Next, in the simulation method of this embodiment, the computer 1 (shown in FIG. 1) rolls the tire model 25 shown in FIG. 11 on the road surface model 27 to calculate the physical quantities of the tire model 25 (step S14). In step S14 of this embodiment, the state in which the tire model 25 comes into contact with and rolls on the road surface model 27 is calculated for each unit time of the simulation.

[0100] In step S14 of this embodiment, deformation calculation (rolling calculation) of the tire model 25 and the road surface model 27 is performed from the start of rolling of the tire model 25 until a predetermined end time has elapsed. The end time can be set appropriately so as to obtain a desired calculation result, for example. For the series of processes in step S14, for example, the above-mentioned commercially available finite element analysis application software is used.

[0101] In step S14 of this embodiment, physical quantities acting on the rolling tire model 25 can be calculated appropriately. Examples of the physical quantities include longitudinal and lateral forces acting on the contact surface of the tire model 25, and physical quantities related to noise. The physical quantities are stored in the computer 1 shown in FIG.

[0102] [Evaluate physical quantities] Next, in the simulation method of this embodiment, it is determined whether or not the physical quantities of the tire model 25 satisfy predetermined criteria (step S15). The criteria can be set appropriately depending on the performance required of the tire 2 shown in Fig. 2. Moreover, the determination of whether or not the physical quantities satisfy the criteria may be made by the computer 1 (shown in Fig. 1) or by an operator.

[0103] If it is determined that the physical quantities of the tire model 25 satisfy the criteria ("Yes" in step S15), the tire 2 is manufactured (step S16) based on design factors such as the pattern constituent units 8 (shown in FIG. 2) used to create the tire model 25. On the other hand, if it is determined that the physical quantities of the tire model 25 do not satisfy the criteria ("No" in step S15), the design factors such as the pattern constituent units 8 are changed (step S17), and steps S11 to S15 are performed again.

[0104] In this way, in the simulation method of this embodiment, the design factors of the tire 2 are changed until the physical quantities of the tire model 25 satisfy the standards, making it possible to design and manufacture a tire 2 having desired performance. Furthermore, in this embodiment, the processing procedure shown in Fig. 3 is used to create the tire model 25, so the tire model 25 with the changed design factors can be created in a short period of time. Therefore, in the simulation method of this embodiment, it becomes possible to design and manufacture a tire 2 having desired performance in a short period of time.

[0105] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified and carried out in various forms. EXAMPLES

[0106] Based on the processing procedure shown in Fig. 3, a numerical analysis model of a tread pattern including the multiple types of pattern constituent units shown in Fig. 2 was created (Example). In the Example, a first step was carried out in which a basic pattern model in which one of the multiple types of pattern constituent units was discretized using a finite number of elements was input. In the Example, hexahedral elements (hex elements) were used from the viewpoint of emphasizing analytical accuracy.

[0107] Next, in the embodiment, a second step was performed in which a deformed pattern model was input in which the elements of the basic pattern model were deformed in the tire circumferential direction to discretize other types of multiple types of pattern constituent units with a finite number of elements. Then, a third step was performed in which a computer arranged the basic pattern model and the deformed pattern model in the tire circumferential direction to create a tread pattern model.

[0108] For comparison, a tread pattern model was created by collectively discretizing the entire circumference of the tread pattern with a finite number of elements (Comparative Example 1). In Comparative Example 1, tetrahedral elements (tetra elements) were used from the viewpoint of improving the reproducibility of the shape of the tread pattern by collective discretization.

[0109] Furthermore, a tread pattern model was created in which only the basic pattern models of the embodiment were arranged in the tire circumferential direction (Comparative Example 2). For discretization of the basic pattern model of this Comparative Example 2, hexahedral elements (hexa elements) were used, as in the basic pattern model of the embodiment. Meanwhile, unlike the tread pattern model of the embodiment, the tread pattern model of Comparative Example 2 does not input a deformed pattern model in which elements of the basic pattern model are deformed in the tire circumferential direction, and therefore a tread pattern including multiple types of pattern constituent units was not reproduced.

[0110] Then, the total creation time of the tread pattern model was compared for the example, comparative example 1 and comparative example 2.

[0111] [Table 1]

[0112] Further, based on the processing procedure shown in Fig. 10, a tire simulation was performed using the tread pattern models of the Example, Comparative Example 1, and Comparative Example 2, and the physical quantities of the tire model were calculated. Furthermore, the physical quantities related to the noise of an actual prototype tire were measured (Experimental Example). Then, for the physical quantities of the Example, Comparative Example 1, and Comparative Example 2, an index was calculated with the physical quantity of the Experimental Example being set to 1.0. Furthermore, the time required for the simulation (analysis time) was compared for the Example, Comparative Example 1, and Comparative Example 2. The results are shown in Table 2.

[0113] [Table 2]

[0114] The common specifications are as follows: Tire size: 205 / 55R16 Rim size: 6.5 x 16J Internal pressure: 230kPa simulation: Noise-related physical quantity: Sound pressure level (dB) Speed: 50km / h Load: 4.22kN

[0115] As shown in Table 1, the tread pattern model of the Example could be created in a shorter time than that of Comparative Example 1. Furthermore, as shown in Table 2, the Example discretized with hexahedral elements approximated the physical quantities of the Experimental Example, despite the shorter analysis time, compared to Comparative Example 1 discretized with tetrahedral elements. Therefore, the simulation accuracy of the Example was improved compared to Comparative Example 1.

[0116] Also, as shown in Table 1, unlike Comparative Example 2, the creation time of the tread pattern model in the embodiment was slightly increased, but since a tread pattern including multiple types of pattern constituent units was reproduced, the simulation accuracy was significantly improved, as shown in Table 2.

[0117] In this way, the embodiment was able to create a tread pattern model in a short time while improving the simulation accuracy.

[0118] [Note] The present invention includes the following aspects.

[0119] [Invention 1] A method for creating a numerical analysis model of a tread pattern including at least a plurality of types of pattern constituent units having different lengths in a tire circumferential direction, comprising: A first step of inputting a basic pattern model into a computer, the basic pattern model being obtained by discretizing one of the plurality of types of pattern constituent units using a finite number of elements; a second step of inputting a deformed pattern model into the computer, the deformed pattern model being obtained by deforming the elements of the basic pattern model in a tire circumferential direction, and discretizing other types of the plurality of types of pattern constituent units into a finite number of elements; and a third step of the computer arranging the basic pattern model and the deformed pattern model in a tire circumferential direction to create a tread pattern model. How to create a tire model. [Invention 2] The second step includes a step of deforming the elements of the basic pattern model so that the shapes of the elements appearing on the connecting surfaces of the basic pattern model and the deformed pattern model are identical to each other. [Invention 3] each of the elements of the basic pattern model and the transformed pattern model includes a plurality of nodes; The third step includes a step of connecting the basic pattern model and the deformed pattern model so that nodes of the basic pattern model and the deformed pattern model appearing on the connecting surface are shared with each other. [Invention 4] The tire model creating method according to any one of claims 1 to 3, wherein the deformed pattern model includes at least one type of extended deformed model obtained by extending the basic pattern model in the tire circumferential direction. [Invention 5] 5. The tire model creating method according to any one of claims 1 to 4, wherein the deformed pattern model includes at least one type of reduced deformation model obtained by shrinking the basic pattern model in the tire circumferential direction. [Invention 6] 6. The tire model creating method according to any one of claims 1 to 5, wherein the third step creates the tread pattern model in an annular shape. [Invention 7] The tire model creating method according to any one of aspects 1 to 6, wherein the third step creates the tread pattern model in a fragmentary form by modeling a portion of the tread pattern in the tire circumferential direction. [Explanation of symbols]

[0120] 11 Basic pattern model 21 Deformed Pattern Model

Claims

1. A method for creating a numerical analysis model of a tread pattern including at least a plurality of types of pattern constituent units having different lengths in a tire circumferential direction, comprising: a first step of inputting a basic pattern model into a computer, the basic pattern model being obtained by discretizing one of the plurality of types of pattern constituent units using a finite number of elements; a second step of inputting a deformed pattern model into the computer, the deformed pattern model being obtained by deforming the elements of the basic pattern model in a tire circumferential direction, and discretizing other types of the plurality of types of pattern constituent units into a finite number of elements; and a third step of the computer arranging the basic pattern model and the deformed pattern model in a tire circumferential direction to create a tread pattern model. How to create a tire model.

2. 2. The tire model creating method according to claim 1, wherein the second step includes a step of deforming the elements of the basic pattern model so that shapes of the elements appearing on a connection surface of the basic pattern model and the deformed pattern model are identical to each other.

3. each of the elements of the basic pattern model and the transformed pattern model includes a plurality of nodes; 3. The tire model creation method according to claim 2, wherein the third step includes a step of connecting the basic pattern model and the deformed pattern model so that nodes of the basic pattern model and the deformed pattern model appearing on the connection surface are shared with each other.

4. The tire model creation method according to claim 1 , wherein the deformed pattern model includes at least one type of extended deformed model obtained by extending the basic pattern model in the tire circumferential direction.

5. The tire model creating method according to claim 1 , wherein the deformed pattern model includes at least one type of reduced deformation model obtained by shrinking the basic pattern model in the tire circumferential direction.

6. The tire model creating method according to claim 1 , wherein the third step creates the tread pattern model in an annular shape.

7. 2. The tire model creating method according to claim 1, wherein the third step creates the tread pattern model in a fragmentary form by modeling a portion of the tread pattern in the tire circumferential direction.

Images