JP2023070896A - Tire model and creation method of tire model - Google Patents

Abstract

To provide a tire model enabling a tire performance evaluation considering the influence of a design of a tire side surface.SOLUTION: A tire model 1 is a model to be used for computer simulation of a tire. The tire model 1 has a first model part 10 for reproducing a tire body, a second model part 20 for reproducing a tire surface shape including a tread pattern, and a joint line 30 for combining the first model part 10 and the second model part 20. The second model part 20 includes a side design region 23 in which the design of a tire side surface is reproduced. The joint line 30 extends to a position corresponding to the side design region 23 of the second model part 20.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a tire model and a method for creating a tire model, and more particularly to a tire model used for computer simulation of tires.

Conventionally, a tire model that reproduces the surface shape and internal structure of a tire and is used for computer simulation of the tire is widely known. For example, Patent Literatures 1 and 2 disclose a method of creating an FEM model of a tire by dividing the tire into finite elements and predicting tire performance by computer simulation using the FEM model. Patent Literatures 1 and 2 disclose a tire model configured by combining a tread model that models a tread and a casing model that models a portion excluding the tread.

JP-A-2002-306838 JP 2004-317832 A

In recent years, when evaluating the aerodynamic performance of a tire, the uneven shape of the tire side surface is often regarded as important. For this reason, it is required to perform a simulation that takes into account the effect of the design of the tire side surface, but the conventional tire model generally omits the design of the tire side surface (Fig. 4, which will be described later). reference).

An object of the present invention is to provide a tire model that enables tire performance evaluation that takes into account the influence of the design of the tire side surface.

A tire model according to the present invention is a model used for computer simulation of a tire, and includes a first model portion that reproduces a tire body, a second model portion that reproduces a tire surface shape including a tread pattern, and the first model portion. A model portion and a joint line for combining the second model portion, the second model portion includes a side design area that reproduces the design of the tire side surface, and the joint line is the side design area. extends to a position corresponding to

A method for creating a tire model according to the present invention is a method for creating a tire model used for computer simulation of a tire, and comprises steps of creating a first model portion that reproduces a tire body, a region that reproduces a tread pattern, and creating a second model portion including a side design area that reproduces the design of the tire side; and combining the first model portion and the second model portion, wherein the first model portion and the second model portion are combined. A joining line for combining the parts extends to a position corresponding to the side design area.

According to the tire model according to the present invention, it is possible to efficiently evaluate tire performance in consideration of the influence of the design of the tire side surface.

It is a figure which shows a part of width direction cross section of the tire model which is an example of embodiment. FIG. 4 is a plan view showing a part of the second model part as an example of the embodiment; It is a figure which shows the tire model which is another example of embodiment. It is a figure which shows an example of the conventional tire model.

Hereinafter, an example of an embodiment of a tire model and a method for creating a tire model according to the present invention will be described in detail with reference to the drawings. The embodiments described below are merely examples, and the present invention is not limited to the following embodiments. In addition, the present invention includes a configuration in which each component of a plurality of embodiments and modified examples described below are selectively combined.

FIG. 1 is a diagram showing a tire model 1 that is an example of an embodiment. FIG. 1 shows a part of a two-dimensional cross section of a tire model 1. FIG.

As shown in FIG. 1, a tire model 1 includes a first model portion 10 that reproduces a tire body, a second model portion 20 that reproduces a tire surface shape including a tread pattern, the first model portion 10 and a second model. and a joining line 30 for assembling the parts 20 together. A tire body is a portion that constitutes the frame of a tire and does not include the design of the tire surface. According to the tire model 1, the first model portion 10 and the second model portion 20 can be handled separately. For example, one type of first model section 10 and multiple types of second model sections 20 are prepared, and multiple types of tire models 1 can be created by combining each of the second model sections 20 and the first model sections 10 .

A tire model 1 is a model for computer simulation of a tire. Although details will be described later, the second model portion 20 includes a first region 21 that reproduces the tread pattern and a second region 22 that reproduces the shape of the upper part of the tire side surface. The second area 22 includes a side design area 23 that reproduces the design of the tire side surface. A joining line 30 defined as a joining position of the first model portion 10 and the second model portion 20 extends to a position corresponding to the side design region 23 .

According to tire model 1, in tire performance evaluation using computer simulation, it is possible to consider not only the tread pattern but also the design formed on the tire side surface (hereinafter sometimes referred to as "side design"). It is possible. The joining line 30 preferably extends inward in the tire radial direction to a position beyond the tire radial inner end (side design end) of the side design region 23 . In this case, the entire side design region 23 is included in the second model portion 20, and performance evaluation can be performed in consideration of the entire side design.

A computer simulation using the tire model 1 is performed, for example, based on the finite element method (FEM). FEM divides the structure to be analyzed into finite elements and performs analysis by calculating the equation of motion for each element. A tire model 1 illustrated in FIG. 1 is an FEM model mesh-divided into a plurality of elements. FIG. 1 shows a part of a two-dimensional cross section divided into a plurality of elements in the tire width direction and radial direction, but the tire model 1 is a three-dimensional model divided into a plurality of elements also in the tire circumferential direction. is preferred.

A simulation using the tire model 1 is performed using a computer with a processor and memory. The tire model 1 may be created by the computer used for the simulation, or may be created by another computer. In this embodiment, it is assumed that the tire model 1 is created and the simulation using the model is performed by the same computer. According to the tire model 1, performance evaluation considering the uneven shape of the tire side surface is possible, so the simulation using the tire model 1 is, for example, the aerodynamic performance of the tire, the air cooling performance, the rigidity of the tire side surface, the cut resistance performance, etc. is useful for the evaluation of

The processor reads out and executes a program stored in the memory, for example, to execute each step for creating a tire model 1, which will be described later, and to execute each step of a simulation using the tire model 1. The memory is composed of RAM, ROM, hard disk, etc., and stores various setting information including simulation programs, tire model 1 creation conditions, material property values, boundary conditions, and the like. Note that the computer may be composed of one computer, or may be composed of a plurality of computers.

The first model portion 10 and the second model portion 20 that constitute the tire model 1 are divided into a plurality of elements by mesh. The first model section 10 and the second model section 20 are models that are created independently of each other, and for example, the number of mesh divisions, element shapes, sizes, etc. are different in each model section. In addition, there are a plurality of types of element shapes and sizes in each model portion. The tire model 1 is data obtained by quantifying a tire in the form of input data to a computer program so that it can be analyzed based on a mathematical method, and has data on the surface shape and internal structure of the tire.

The tire model 1 is created by using a tire shape in a natural equilibrium state as a reference shape and modeling this reference shape by FEM. Each node of the finite element of the tire model 1 is specified by three-dimensional coordinates. The tire model 1 is, for example, a tire body shape created by two-dimensional CAD software, mesh generation is performed using mesh creation software, and a first model portion obtained by developing it in the tire circumferential direction, and a three-dimensional CAD A second model section created by using three-dimensional data representing the shape of the tread pattern and side design area created by software or three-dimensional modeling software and performing mesh generation on the three-dimensional data using mesh creation software. created by combining The mesh shape is preferably polygonal, generally quadrangular or triangular (hexa-mesh or tetra-mesh in the case of three dimensions), or a mixture thereof.

The first model portion 10 and the second model portion 20 are models independent of each other, and are connected by a joining line 30 to form one tire model 1 . In the present embodiment, the cross section in the width direction of the tire model 1 has a symmetrical shape with respect to the tire equator passing through the center in the width direction. By preparing one kind of first model portion 10 and plural kinds of second model portions 20 and changing only the second model portion 20, plural kinds of tire models 1 can be created. Even when a plurality of types of second model parts 20 are prepared, for example, the joint lines 30 of each model are set to have the same shape and the same length.

As described above, the first model portion 10 is an FEM model that reproduces the tire body, and is created by developing a cross-sectional model along the width direction and radial direction of the tire in the circumferential direction. A tire body is a portion that constitutes the frame of a tire, and includes a carcass, a belt, beads (bead core and bead filler), sidewall rubber, an inner liner, and the like. The first model portion 10 includes a carcass region 11 that reproduces a carcass, a belt region 12 that reproduces a belt, a bead region 13 that reproduces a bead, and a rubber region 14 that reproduces a rubber portion such as sidewall rubber. there is

The first model portion 10 has a substantially constant thickness in the region corresponding to the buttress region of the tire. In other words, the joining line 30 is defined such that the thickness of the first model portion 10 is substantially constant. In this case, variations in size of each element generated by mesh division can be suppressed, and analysis accuracy can be improved. In this specification, the buttress region is defined as the region located in the upper portion of the tire side portion, more specifically, the region located in the range from the ground contact edge of the tire to the portion where the tire has the maximum width. do.

FIG. 2 is a plan view of the second model section 20. FIG. FIG. 2 shows a model for one pitch, which is the minimum unit of repetition. The second model portion 20 is created by repeating a necessary number of detailed shape models that reproduce the tire surface shape in the circumferential direction. The second model part 20 is meshed more finely than the first model part 10 . A first area 21 of the second model portion 20 is an area that reproduces a tread pattern in contact with the road surface. In the first region 21, for example, circumferential grooves, widthwise grooves, and land portions partitioned by the respective grooves are reproduced. The second region 22 is a region that reproduces the shape of the upper portion of the tire side surface located on the outer side in the width direction of the ground contact edge.

The second area 22 includes a side design area 23 that reproduces the side design. Examples of side designs include side blocks, uneven shapes on the side surfaces of shoulder blocks of the tread, and side ribs formed along the tire circumferential direction. The uneven shapes on the side surfaces of the side blocks and shoulder blocks are generally arranged in predetermined repeating units in the tire circumferential direction and contribute to improvement in cut resistance and the like. The side design also affects the aerodynamic performance of the tire. One pitch shown in FIG. 2 corresponds to the minimum unit of repetition of the tread pattern and side design.

The joining line 30 is defined as a joining position of the first model portion 10 and the second model portion 20 in the cross section of the tire model 1 in the width direction. The central portion of the joining line 30 is formed substantially straight, and both ends of the joining line 30 and the vicinity thereof are greatly curved. The joining line 30 extends from a position corresponding to the tread pattern to a position corresponding to the side design. The joining line end 30E preferably coincides with the tire radially inner end (side designed end) of the side design region 23 or is set radially inward of the side designed end. In this case, the entire side design can be modeled in the second model section 20 .

The joining line 30 is largely curved so as to be convex toward the outside of the tire from a predetermined position on the outer side in the tire width direction of the position corresponding to the ground contact end to the joining line end 30E. The predetermined position at which the joint line 30 begins to bend is set at a position where the thickness of the first model portion 10 arranged inside the joint line 30 is substantially constant without locally changing largely. That is, the joining line 30 is curved so that the thickness of the first model portion 10 is substantially constant at least in the region corresponding to the buttress region of the tire. The first model portion 10 may be formed so that the thickness of the portion other than the bead region 13 is substantially constant.

The joint line end 30E can be set according to the shape and size of the side design to be evaluated. The splice line end 30E is usually set at a position corresponding to the buttress area of the tire. The position of the joint line end 30E is, for example, constant along the tire circumferential direction, and is preferably set at a position exceeding the side design end positioned furthest in the tire radial direction.

A second region 22 of the second model portion 20 is arranged outside the curved portion of the joining line 30 . The thickness of the second region 22, except for the side design region 23, gradually decreases from the first region 21 side toward the joining line end 30E. In this embodiment, the second model section 20 is divided into a plurality of elements mainly by hexamesh. That is, the second model part 20 is mesh-divided so that the number of hexamesh layers in the thickness direction of each region is the same.

In this embodiment, in the second region 22 of the second model portion 20, the side design region 23 exists outside the profile line along the surface of the first region 21 (tread surface). In this case, the side design regions 23 are arranged such that the thickness of the elements constituting the region and the thickness of the elements located inside the side design regions 23 are the same or similar to each other. , is preferably divided into meshes.

When two or more hexamesh layers are present in the side design region 23, it is preferable that the thickness of each hexamesh layer is substantially the same. That is, while setting the thickness of the hexamesh layer in the side design region 23 to the same extent, the thickness is set as close as possible to the thickness of the hexamesh layer in the portion located inside the side design region 23 of the second region 22. set. By dividing into meshes in this way, the accuracy of FEM analysis is improved.

FIG. 3 is a diagram showing a modification of the mesh division form of the side design area 23. As shown in FIG. The embodiment illustrated in FIG. 3 differs from the embodiment illustrated in FIG. 4 in that the side design region 23 is divided into a plurality of elements by tetra mesh. For example, if the shape of the side design area 23 is complicated, the side design area 23 is divided using tetra mesh or using both hexa mesh and tetra mesh. In this case, it is preferable to divide the side design region 23 into meshes so that the length of one side of the tetra mesh and the thickness of the tetra mesh layer are approximate to each other.

The tire model 1 having the configuration described above is created, for example, by the following procedure.
(1) Step of creating the first model portion 10 that reproduces the tire body (2) Including the first region 21 that reproduces the tread pattern and the side design region 23 (second region 22) that reproduces the design of the tire side surface Step (3) of creating second model portion 20: Step of combining first model portion 10 and second model portion 20 Note that the order in which the first model portion 10 and the second model portion 20 are created is not particularly limited. The tire surface shape of the second model portion 20 is created using three-dimensional CAD software or the like, and is mesh-divided into finite elements. Then, material property values are set for each element in accordance with rubber compounding.

In the process of creating the tire model 1, a joining line 30 for combining the first model portion 10 and the second model portion 20 is defined. The joining line 30 is a line extending from a position corresponding to the tread pattern to a position corresponding to the side design region 23, greatly exceeding the position corresponding to the ground contact edge. The splice line end 30E is preferably set at a position coinciding with or beyond the side design edge. Moreover, the joining line 30 is preferably set so that the thickness of the first model portion 10 is substantially constant at least in the region corresponding to the buttress region of the tire.

In addition, from the viewpoint of improving the accuracy of FEM analysis, the side design region 23 has the same thickness of the elements forming the region and the thickness of the elements located inside the side design region 23, as described above. Alternatively, it is preferable to perform mesh division so that the thickness is approximated. The thickness difference between each element in the side design region 23 and its inner portion is preferably within 40%, more preferably within 20%.

FIG. 4 is a diagram showing a part of a two-dimensional cross section of a conventional tire model 50. As shown in FIG. A tire model 50 includes a first model portion 51 that reproduces a tire body, a second model portion 52 that reproduces a tire surface shape including a tread pattern, and a joint for combining the first model portion 10 and the second model portion 20. It is common with the tire model 1 in that it has a line 53 . On the other hand, the joint line 53 is formed in a substantially straight line, and the second model portion 52 does not substantially include the region corresponding to the side portion of the tire. That is, the second model portion 52 does not have a region that reproduces the design of the tire side surface. Moreover, the design of the tire side surface is not modeled in the first model portion 51 either.

On the other hand, in the tire model 1, the joint line 30 extends to the region corresponding to the side design, and the second model portion 20 includes the first region 21 reproducing the tread pattern and the side design reproducing the design of the tire side surface. A region 23 (second region 22) is included. Therefore, the simulation using the tire model 1 enables efficient tire performance evaluation taking into account not only the tread pattern but also the design of the tire side surface.

A simulation using the tire model 1 is suitable for evaluating performance that is likely to be affected by the design of the tire side surface. An example of performance evaluation using the tire model 1 is evaluation of tire aerodynamic performance and the like.

Moreover, the joining line 30 is preferably defined so that the thickness of the first model portion 10 is substantially constant at least in the region corresponding to the buttress region of the tire. In this case, the variation in the size of each element of the first model section 10 is suppressed, and the accuracy of FEM analysis is improved.

It should be noted that the above-described embodiment can be appropriately modified in design within the scope of the present invention. For example, the cross section of the tire model 1 in the width direction has a symmetrical shape with respect to the tire equator, but the tire model according to the present invention may have a laterally asymmetric shape with respect to the tire equator.

1 tire model, 10 first model part, 11 carcass area, 12 belt area, 13 bead area, 14 rubber area, 20 second model part, 21 first area, 22 second area, 23 side design area, 30 joining line , 30E line end

Claims (4)

A tire model used for computer simulation of a tire,
The first model part that reproduces the tire body,
a second model portion that reproduces the tire surface shape including the tread pattern;
a joining line for combining the first model part and the second model part;
has
The second model portion includes a side design area that reproduces the design of the tire side surface,
The tire model, wherein the joint line extends to a position corresponding to the side design area. The tire model according to claim 1, wherein the joining line is curved so that the thickness of the first model portion is substantially constant in a region corresponding to a buttress region of the tire. The first and second model parts are meshed into finite elements,
In the side design region, the thickness of the elements constituting the design region and the thickness of the elements located inside the design region are the same or similar to each other. 3. Tire model according to claim 1 or 2, which is segmented. A method for creating a tire model used for computer simulation of tires, comprising:
creating a first model portion that reproduces the tire body;
a step of creating a second model portion including a region that reproduces the tread pattern and a side design region that reproduces the design of the tire side;
combining said first model part and said second model part;
including
A method for creating a tire model, wherein a joining line for combining the first model portion and the second model portion extends to a position corresponding to the side design region.

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