WO2016031811A1

WO2016031811A1 - Method for generating tire model, device for generating tire model, simulation method for tire, and non-transitory computer-readable medium

Info

Publication number: WO2016031811A1
Application number: PCT/JP2015/073847
Authority: WO
Inventors: 直哉古渡; 正隆小石
Original assignee: 横浜ゴム株式会社
Priority date: 2014-08-25
Filing date: 2015-08-25
Publication date: 2016-03-03
Also published as: JP6601401B2; JPWO2016031811A1

Abstract

Multiple templates are generated from a generated reference tire model in the present invention when generating a tire model of a pneumatic tire, each template representing a change amount distribution for changing the outer profile of the tire. A base tire model is generated using the reference tire model and one of the templates, said base tire model having an outer profile formed by changing the outer profile of the reference tire model. Furthermore, when repeating the generation of base tire model, at least one more base tire model is generated using, among the templates, a template which represents a change amount distribution different from the change amount distribution already used for generating the base tire model. Multiple composite tire models are generated by combining the generated multiple base tire models.

Description

Tire model creation method, tire model creation device, tire simulation method, and non-transitory computer-readable medium

The present invention relates to a tire model creation method for creating a tire model, a tire model creation device, a tire simulation method, and a non-transitory computer-readable medium.

Today, various optimum design methods based on numerical calculations have been proposed in order to search for products with optimal shapes that exhibit optimal product performance by improving high-speed numerical calculation using computers. Thereby, it is said that the optimal design of a product can be performed efficiently. However, the tire as a structure has a problem that the optimum design technique is not sufficiently utilized due to the complexity of the method for defining the shape of the tire cross section.

On the other hand, the optimal shape design method used suitably for tire design is known (patent document 1).
In this optimum shape design method, a plurality of base cross-sectional shapes of the product shape are made deformed shapes of the natural vibration mode of the product shape, and a plurality of sample product shapes are generated by linearly combining the base cross-sectional shapes based on the experimental design method. Then, the evaluation value of the product performance of the generated sample product shape is obtained, and the optimum product shape with the evaluation value being the optimum value is extracted based on the evaluation value of the product performance.

Japanese Patent Laid-Open No. 2002-15010

When the above-described known optimum shape design method is applied to the tire cross-sectional shape, the base cross-sectional shape is limited because the deformation shape in the natural vibration mode of the tire cross-sectional shape is the base cross-sectional shape of the tire cross-sectional shape. For this reason, the optimum product shape of the tire extracted using the base cross-sectional shape is also limited to the range of the combined shape obtained by combining the deformed shapes in the natural vibration mode. For this reason, the optimum product shape of the tire obtained by the above-described optimum shape design method cannot always sufficiently improve the tire performance.
Further, in the above-described optimum shape design method, if the tire size is different, the reference tire cross-sectional shape that is the basis of the base cross-sectional shape is also different, so that the tire cross-sectional shape cannot have consistent characteristics regardless of the tire size.

Therefore, in the present invention, when creating a tire model of a pneumatic tire, the created tire cross-sectional shape is not limited to the combined shape combining the deformed shapes in the natural vibration mode, and the tire cross-sectional shape is efficiently created. It is an object to provide a tire model creation method, a tire model creation device, a tire simulation method using the tire model creation method, and a computer-readable medium.

The tire model creation method of the present technology is a method of creating a tire model of a pneumatic tire from a reference tire model using a computer. The method is
A first step of creating a plurality of templates representing a distribution of a change amount for changing an outer shape from a reference tire model by a computer;
A second step of creating the reference tire model by the computer;
A third step of creating a base tire model having an outer shape in which an outer shape of the reference tire model is changed by the computer using the reference tire model and one of the templates;
A base tire model having a different external shape from a base tire model that has already been created using a template that represents a distribution of the amount of change different from the distribution of the amount of change already used to create the base tire model. A fourth step of creating at least one of
By combining the plurality of base tire models created in the third step and the fourth step by the computer, the plurality of base tire models have an outer shape different from the outer shape of the reference tire model, and the outer shapes are different from each other. And a fifth step of creating a synthetic tire model.

In the second step, a reference tire model group in which at least one of a tire outer shape, a tire size, and a tire structure is different is created, and one of the reference model groups is the reference model,
Further, the plurality of synthetic tire models are created by repeating the third step and the fourth step according to the number of the templates, using the template for each of the created reference tire model groups. It is preferable to do.

In the third step and the fourth step, the computer acquires an outer contour line of the reference tire model or a carcass line of the reference tire model, and uses the outer contour line or the carcass line. Preferably, the base tire model is created by changing the template.

The reference tire model is a set of elements formed by a plurality of nodes and a plurality of sides connecting the plurality of nodes.
In the third step and the fourth step, the computer associates both ends of at least a part of the distribution of the change amount of the template with nodes on the contour line or the carcass line. Therefore, the region of the template is enlarged or reduced in accordance with the distance on the outer shape contour line between the nodes or the distance on the carcass line, and the outer shape of the reference tire model is obtained from the distribution of the enlarged and reduced regions. Preferably, the base tire model is created by determining the amount of movement of each node on the contour line or the carcass line and changing the shape of the outer contour line or the carcass line.
At this time, it is preferable that the region of the template is enlarged or reduced so that the region corresponds to at least one range of a tread portion, a side portion, and a bead portion of the reference tire model.

The reference tire model is a model that can be subjected to calculation of shape deformation analysis by the computer. In the third step and the fourth step, the computer performs the outline shape contour line of the reference tire model or the Preferably, the base tire model is created by deforming the shape of the reference tire model by applying a forced displacement corresponding to the movement amount to each node on the carcass line and performing the shape deformation analysis. .

In the fifth step, the computer creates a composite vector by weighting and adding a plurality of tire base vectors representing a difference between each of the plurality of base tire models and the shape of the reference tire model, and the composite Preferably, the synthetic tire model is created by deforming the reference tire model based on a vector.

In the synthetic tire model, the number of ends of the cord material and the inclination angle of the cord material set in the synthetic tire model are calculated from the number of ends of the cord material and the inclination angle of the cord material set in the reference tire model. It is preferable to change according to the deformation shape from the tire model.

Another aspect of the present technology is a tire simulation method. The simulation method calculates a physical quantity of tire characteristics of the synthetic tire model by performing a simulation reproducing the behavior of the tire using the synthetic tire model created by the tire model creation method.

Still another aspect of the present technology is a tire simulation method. In the simulation method, by using the synthetic tire model created by the tire model creation method, by performing a simulation to reproduce the behavior of the tire, to calculate the physical quantity of the tire characteristics of the synthetic tire model, A weighting coefficient used when weighting and adding the tire base vector is a design variable, the physical quantity calculated by the simulation is an objective function, and the design variable is set so that the objective function satisfies a preset condition. A step of changing the value.

Furthermore, it is preferable that the computer visualizes and displays the relationship between the physical quantity and the feature value representing the weighting coefficient value or the shape of the synthetic tire model.

Still another embodiment of the present technology is a tire model creation device that creates a tire model of a pneumatic tire. The tire model creation device
A reference tire model creation unit configured to create a reference tire model;
A template creation unit configured to create a plurality of templates representing a distribution of a change amount for changing the outer shape from the reference tire model;
A base tire model creation unit configured to create a base tire model having an outer shape in which an outer shape of the reference tire model is changed using one of the reference tire model and the template;
A template that controls the base tire model creation unit so as to repeat the creation of the base tire model, and represents a change amount distribution different from the change amount distribution already used for creating the base tire model among the templates. A control unit configured to control the base tire model creation unit so as to create at least one base tire model having a different external shape from the already created base tire model,
A composite tire model creation unit configured to create a plurality of composite tire models having a different external shape from the external shape of the reference tire model by combining a plurality of created base tire models And comprising.

Yet another aspect of the present technology is a non-transitory computer-readable medium that records a program that executes a method of creating a tire model of a pneumatic tire from a reference tire model using a computer.
The method
Let the computer create multiple templates that represent the distribution of the amount of change to change the outer shape from the reference tire model,
Causing the computer to create the reference tire model;
Using the one of the reference tire model and the template, the computer creates a base tire model having an outer shape in which the outer shape of the reference tire model is changed,
A base tire model having a different external shape from the base tire model that has already been created by using a template that represents a distribution of the amount of change different from the distribution of the amount of change already used to create the base tire model, among the templates. To repeatedly create
And causing the computer to create a plurality of synthetic tire models having an outer shape different from the outer shape of the reference tire model by combining the plurality of created base tire models.

In the tire model creation method, tire model creation device, and non-transitory computer-readable medium described above, the tire cross-sectional shape to be created is not limited to the combined shape that combines the deformed shapes in the natural vibration mode. The tire cross-sectional shape can be created efficiently. In the tire simulation method described above, since the simulation is performed using the synthetic tire model created by the tire model creation method described above, the optimum tire cross-sectional shape that sufficiently improves the tire performance is obtained from the simulation result. Can be obtained.

It is a figure explaining the flow of the simulation method of the tire containing the tire model creation method of this embodiment. It is a block block diagram of the simulation apparatus which performs the preparation method of the tire model of this embodiment, and the simulation method of a tire. It is sectional drawing of an example of the reference | standard tire model created by this embodiment. (A)-(c) is a figure which shows the example of the template used by this embodiment. It is a figure explaining the method of producing a base tire model by changing the external shape outline of the standard tire model created in this embodiment. (A)-(e) is a figure explaining the expansion and contraction of a partial area | region of the distribution of the variation | change_quantity of the template used by this embodiment, a reference | standard tire model, and a base tire model. It is a figure explaining the example of preparation of the synthetic tire model used by this embodiment.

Hereinafter, a tire model creation method, a tire model creation device, a tire simulation method, and a computer-readable medium according to the present embodiment will be described based on the embodiments shown in the accompanying drawings.

(Tire model creation method and tire simulation method of this embodiment)
In the tire model creating method of the present embodiment, it is executed by a computer.
The tire model creation method of this embodiment is used as part of the simulation method of this embodiment. FIG. 1 is a diagram illustrating a flow of a tire model creation method and a tire simulation method according to the present embodiment.

First, the computer creates a plurality of templates representing the distribution of the amount of change for changing the outer shape from the reference tire model (step S1). Further, the computer creates a reference tire model modeled by the finite element method or the like (step S2). The reference tire model is a tire model having a tire cross-sectional shape that is a basis of the synthetic tire model, and is a tire model before the outer shape is changed by the tire model creation method and the tire simulation method of the present embodiment.
Thereafter, the computer creates a base tire model having an outer shape in which the outer shape of the reference tire model is changed using one of the reference tire model and the template (step S3). Further, the computer determines whether or not N (N is a natural number) base tire models have been created (step S4). If the number of base tire models created is less than N, the base tire model creation is repeated. At this time, the computer uses a template representing a variation distribution different from the variation distribution already used to create the base tire model, and the base tire has a different outer shape from the base tire model already created. At least one model is created (step S3). When N base tire models are created in the determination of step S4, the computer combines a plurality of the created base tire models to generate a plurality of synthetic tire models having an outer shape different from the outer shape of the reference tire model ( M: M is a natural number) (step S5). The above is the tire model creation method of the present embodiment.

Furthermore, using the synthetic tire model created by this method, the computer calculates a simulation that reproduces the behavior of the tire for calculating the tire characteristics (step S6). Thereby, the physical quantity of the tire characteristic of the synthetic tire model is calculated. The computer determines whether or not the simulation calculation has been performed M times by replacing the synthetic tire model (step S7). The computer repeats the simulation calculation by replacing the synthetic tire model until the simulation calculation is performed M times.
Finally, the computer optimizes the tire cross-sectional shape using the physical quantity of the tire characteristics of the synthetic tire model (step S8).

Thus, when creating a base tire model, a plurality of base tire models having different outer shapes are created using a plurality of templates having different distributions of variation. For this reason, as conventionally, the tire cross-sectional shape of the synthetic tire model to be created is not limited to the combined shape combining the deformed shapes in the natural vibration mode, and the tire cross-sectional shape can be efficiently created based on the template. it can.

FIG. 2 is a block diagram of a simulation apparatus that executes the tire model creation method and the tire simulation method. A part of the simulation apparatus shown in FIG. 2 is also a tire model creation apparatus that creates a tire model.

The simulation apparatus 10 is configured by a computer, and includes a computer main body 12, a printer 14, a display 16, and a mouse / keyboard 18. A printer 14, a display 16, and a mouse / keyboard 18 are connected to the computer main body 12. The computer main body 12 includes a storage unit 20 including a RAM, a ROM, a heart disk, and the like, a CPU 22, and an analysis processing unit 24.
The analysis processing unit 24 includes a reference tire model creation unit 26, a template creation unit 28, a base tire model creation unit 30, a synthetic tire model creation unit 32, a control / management unit 34, a simulation calculation unit 36, and a determination unit 38. The reference tire model creation unit 26, template creation unit 28, base tire model creation unit 30, synthetic tire model creation unit 32, control / management unit 34, simulation calculation unit 36, and determination unit 38 are stored in the storage unit 20. This is a module formed by calling a program and executing the program by the CPU 22. That is, the analysis processing unit 24 is a software module in which the CPU 22 controls the substantial operation of the analysis processing unit 24.

The reference tire model creation unit 26 performs a step S2 shown in FIG. 1 and creates a reference tire model including a finite element model that reproduces a reference tire for creating a synthetic tire model.

The template creation unit 28 creates a plurality of templates that represent the distribution of the amount of change for changing the outer shape from the reference tire model in the part that executes step S1 shown in FIG.

The base tire model creation unit 30 is a part that executes step S3 shown in FIG. 1, and creates a base tire model having an outer shape that changes the outer shape of the reference tire model by using one of the reference tire model and the template. To do. The base tire model creation unit 30 creates a plurality (N) of base tire models. At this time, at least one or more base tire models are created using a template representing a distribution of change amounts different from the distribution of change amounts already used for creating the base tire model. As a result, the base tire model that is created has a different external shape from the base tire model that has already been created.

The synthetic tire model creation unit 32 executes step S5 shown in FIG. 1 and creates a plurality of synthetic tire models having an outer shape different from the outer shape of the reference tire model by combining the plurality of created base tire models. To do. The external shapes of the created synthetic tire models are different from each other.

The control / management unit 34 is a part that manages the operations of the reference model creation unit 26, the template creation unit 28, the base tire model creation unit 30, the synthetic tire model creation unit 32, the simulation calculation unit 36, and the determination unit 38. For example, the control / management unit 34 controls the base tire model creation unit 30 to repeat the creation of the base tire model. At this time, at least a base tire model having an outer shape different from that of the base tire model already created by using a template representing a distribution of change amount different from the distribution of the change amount already used for creating the base tire model. The base tire model creation unit 30 is controlled to create one or more.

The simulation calculation unit 36 is a part that executes Step S6 shown in FIG. 1, and uses the created synthetic tire model to perform a simulation calculation that reproduces the behavior of the tire, whereby the physical quantity of the tire characteristics of the synthetic tire model is calculated. Is calculated.

The determination unit 38 is a part that executes step S8 shown in FIG. 1, and uses a weighting coefficient used when creating a synthetic tire model by combining a base tire model as a design variable, and a physical quantity calculated by simulation as an objective function. The synthetic tire model having the optimum tire cross-sectional shape is extracted by changing the value of the design variable so that the objective function satisfies the set condition. In other words, the determination unit 38 optimizes the tire cross-sectional shape so that the objective function satisfies a preset condition.
Hereinafter, the operation of the tire model creation method and simulation method and the tire model creation apparatus 10 will be described in more detail.

First, the template creation unit 28 creates a plurality of templates representing the distribution of change amounts for changing the outer shape from the reference tire model (step S1). The reference tire model will be described later. FIG. 3 is a cross-sectional view of an example of a reference tire model.
The template is information representing position information from the reference point and a change amount of each position. The template is expressed by a function or linearly interpolated by dividing into a section. 4A to 4C are diagrams showing examples of templates. 4A to 4C, the horizontal axis represents the position from the reference point, and the vertical axis represents the amount of change. The distribution of the change amount can be freely created by operator settings. The distribution shown in FIG. 4A is a distribution in which the amount of change is the largest in the central region of the change amount distribution range (the range from the reference point S to the point E in the figure). ) Is a distribution in which the change amount is maximum in the second half part of the change amount distribution range, and the distribution shown in FIG. 4C is a distribution in which the change amount is maximum in the first half part of the change amount distribution range. is there. The created template is stored in the storage unit 20.

Next, the reference tire model creation unit 26 creates a reference tire model that is a finite element model (step S2). FIG. 3 is a cross-sectional view of an example of the reference tire model 40 to be created. The reference tire model 40 is a model obtained by dividing a model of a pneumatic tire to be analyzed (whether or not it actually exists) by a finite number of small elements. The reference tire model 40 is an aggregate of elements constituted by a plurality of nodes and a plurality of sides connecting the plurality of nodes. The reference tire model 40 may be a three-dimensional model or a two-dimensional axisymmetric tire model. The two-dimensional axisymmetric model is a model in which a two-dimensional cross-sectional shape is transferred in the tire circumferential direction and the same cross-sectional shape is continuous in the tire circumferential direction.
In the case of the three-dimensional model, for example, a tetrahedral to hexahedral solid element for reproducing a rubber member, a membrane element for reproducing a cord reinforcing layer including a cord material, a shell element, and the like are used as each element. In the case of the two-dimensional axisymmetric model, for example, a triangular or quadrilateral solid element for reproducing a rubber member, a membrane element for reproducing a cord reinforcing layer including a cord material, a shell element, or the like is used as each element.
In the reference tire model 40 created in this way, at least the node number of each element, the coordinate value of the node, and the element shape are set, and these pieces of information are stored in the storage unit 20.
Note that either the template creation or the reference tire model 40 creation may be performed first.

Next, the base tire model creation unit 30 calls the reference tire model 40 and one of the templates from the storage unit 20, and uses them to select a base tire model having an outer shape that is a change in the outer shape of the reference tire model 40. Create (step S3). At this time, the base tire model creation unit 30 acquires the outer shape contour line of the reference tire model 40 or the carcass line of the reference tire model 40 from the reference tire model 40, and the acquired outer shape contour line or carcass line is obtained. It is preferable to create the base tire model 42 by changing it using a template called from the storage unit 20. Thereby, even if a groove is provided in the tread portion of the reference tire model 40, the tire cross-sectional shape of the base tire model can be easily created.

FIG. 5 is a diagram for explaining a method of creating the base tire model 42 by changing the outer shape contour line of the reference tire model 40. The outer shape contour line is a contour shape of a portion of the surface of the tread portion, the side portion, and the bead portion that does not include a locally recessed portion such as a groove provided in the tread portion. In FIG. 5, an outline contour line 41 is shown on the reference tire model 40. In addition, an outline contour line 43 of the base tire model 42 is also shown. In FIG. 5, the reference tire model 40 and the base tire model 42 are displayed with only nodes. In the present embodiment, when creating the base tire model 42, the outer contour line is deformed by moving the nodes on the outer contour line of the reference tire model 40 according to the distribution of the amount of change in the template. Specifically, the base tire model creation unit 30 determines the distribution of the change amount of the template as a movement amount that the node should move, and uses this movement amount to move the node to deform the outer contour line. Do. Thereby, the base tire model 42 can be created. At this time, the moving direction of the node is preferably a normal direction with respect to the curve of the outer contour line, but may be a preset direction. For example, when the deformation of the tread portion is mainly performed, it is preferable that the moving direction of the node located in the tread portion is the tire radial direction. Further, when mainly deforming the side portion, it is preferable that the moving direction of the node located on the side portion is the tire width direction.

The base tire model creation unit 30 can create the base tire model 42 by performing shape deformation analysis of the reference tire model 40, for example. Specifically, the base tire model creation unit 30 assigns a material constant to each element of the reference tire model 40 and creates a model that can be subjected to shape deformation analysis by a computer. The material constant given to each element may not be the material constant of the actual tire constituent member. Thereafter, a forcible displacement corresponding to the movement amount of the node is given to each node on the outer shape contour line 41 in accordance with the distribution of the change amount of the template, and the shape deformation analysis of the reference tire model 40 is performed. In this shape deformation analysis, the base tire model 42 is created by deforming the shape of the reference tire model 40. The above example is an example of deforming the outer contour line, but the carcass line can be deformed by the above method instead of the outer contour line.

The base tire model 42 may be created by the following method. The base tire model creation unit 30 determines the amount of movement of the nodes by matching the nodes on the outer shape contour line of the reference tire model 40 with the distribution of the change amount of the template, and moves the nodes using the amount of movement to adjust the outer shape. A contour line 43 is created, and all the nodes other than the nodes on the outer shape contour line 43 of the reference tire model 40 are moved in accordance with this. Since the base tire model 42 and the reference tire model 40 have the same constituent elements and differ only in the positions of the nodes, the base tire model creation unit 30 can easily create the base tire model 42 from the reference tire model 40. . The above example is an example of deforming the outer contour line, but the carcass line can be deformed by the above method instead of the outer contour line.
The method for creating the base tire model 42 is not particularly limited, and the base tire model creation unit 30 may create the base tire model 42 by a known method from the deformed outer shape contour line or the carcass line. .

The distribution range of the change amount of the created template (the range from the point S to the point E shown in FIGS. 4A to 4C) is the contour line or carcass of the reference tire model 40 to be deformed. It may not always match the line range. For this reason, the nodes at both ends of the distribution range of the change amount of the template (points S and E shown in FIGS. 4A to 4C) are nodes that form both ends of the range to be deformed of the reference tire model. And the length of the template variation distribution range (the distance from point S to point E shown in FIGS. 4 (a) to 4 (c)) is to be deformed by the reference tire model 40. It is preferable to change the distribution of the amount of change by enlarging / reducing a partial region of the template so that it matches the peripheral length of the outer shape contour line or carcass line of the range.

When the base tire model creating unit 30 deforms the shape from the reference tire model 40 to create the base tire model 42, a part of the outer shape such as the tread portion, the side portion, or the bead portion of the tire is selectively used as the reference tire. There is a case where a base tire model 42 deformed from the outer shape of the model 40 is to be created. For this reason, the template change is made so that the distribution range of the specific change amount determined by the template corresponds to only the portion to be selectively deformed, for example, only to the tread portion or only to the side portion. It is preferable to divide the amount distribution range, and to enlarge or reduce the change amount portion for each divided section. In other words, the base tire model creation unit 30 makes the outer shape contour between the nodes to correspond both ends of at least a part of the distribution of the variation of the template to the nodes on the outer shape contour line or the carcass line. The partial area of the template is enlarged or reduced in accordance with the distance on the line or the distance on the carcass line, and each node on the outer shape contour line of the reference tire model or the carcass line is obtained from the distribution of the enlarged and reduced partial areas. It is preferable to create a base tire model by determining the amount of movement to be moved and deforming the shape of the outer contour line or the carcass line.

FIGS. 6A to 6E are diagrams for explaining the expansion / contraction of a partial region in the above-described template variation amount distribution range, the reference tire model 40, and the base tire model 42. FIG. In the reference tire model 40 and the base tire model 42 in the figure, the nodes and elements are not shown.
FIG. 6A shows an example of a template. One point PA of the ends of the distribution range to be expanded or contracted in the template is located at the node P1 located on the contour line on the tire equator line of the reference tire model 40 shown in FIGS. The other point PB of the two ends of the distribution range to be scaled in the template corresponds to the node P2 at the end of the tread portion shown in FIGS. 6B and 6D, and the distribution of the distribution in the template The base tire model creation unit 30 expands and contracts so that the other point PC of both ends corresponds to the node P3 at the end of the tread portion shown in FIGS. 6 (b) and 6 (d). At that time, furthermore, the distance LA between the point PA and the point PB coincides with the peripheral length (distance on the contour line) L12 between the node P1 and the node P2, and the distance LB between the point PB and the point PC is The range of the distance LA and the range of the distance LB are enlarged or reduced in accordance with the peripheral length L12 and the peripheral length L23 so as to coincide with the peripheral length (distance on the contour line) L23 between the node P2 and the node P3.
As described above, it is preferable that the region of the template is expanded or contracted so that the region to be expanded or contracted in the template corresponds to at least one range of the tread portion, the side portion, and the bead portion of the reference tire model 40. . In other words, it is preferable that the portion whose outer shape is to be changed is set by dividing each of the tread portion, the side portion, and the bead portion into one unit element and combining these unit elements. Further, the side portion is positioned on the outer side in the tire radial direction (tread portion side) with respect to the tire maximum width position, and on the inner side in the tire radial direction (bead portion side) with respect to the tire maximum width position. It can be subdivided into lower side parts to be made into one unit element. In the example shown in FIGS. 6A, 6 </ b> B, and 6 </ b> D, the outer shape is changed to be divided into a range of the tread portion and a range of the side portion and the bead portion. In addition, the carcass line of the reference tire model 40 can be used instead of the outer shape contour line of the reference tire model 40.
The reference tire model 40 shown in FIG. 6 (b) and the reference tire model 40 shown in FIG. 6 (d) have different tire sizes, and the reference tire model shown in FIG. 6 (d) has a wider tread width. In this way, even if the tire sizes are different, the base tire model creation unit 30 performs expansion / contraction by dividing the region of the variation distribution of one template, and the contour distribution line is changed from the distribution of the variation variation. By determining the amount of movement of the node and using this amount of movement, the selected part, for example, the side part has the same shape as shown in FIGS. 6C and 6D, even if the tire size is different. A deformed base tire model 42 can be created. Accordingly, the base tire model creation unit 30 can create a base tire model having a consistent tire cross-sectional shape regardless of the tire size.
The base tire model creation unit 30 creates a base tire model 42 for each of the plurality of templates created in this way, and stores the base tire model 42 in the storage unit 20. The base tire model 42 has the same elements and the same nodes as the reference tire model 40, but is different from the reference tire model 40 in the position coordinates of the nodes.

The synthetic tire model creation unit 32 calls the plurality of base tire models 42 stored in the storage unit 20 and creates a plurality of synthetic tire models (step S5). FIG. 7 is a diagram illustrating an example of creating a synthetic tire model. Specifically, the synthetic tire model creation unit 32 obtains a tire base vector representing a difference between the shapes of the base tire model 42 and the reference tire model 40 for each of a plurality (N) of base tire models 42. 7, tire base vectors 1, 2,..., N in the base tire models 1, 2,. The tire base vector is, for example, a plurality of vectors whose components are differential coordinate values obtained by subtracting the position coordinates of the corresponding nodes of the reference tire model 40 (nodes having the same node number) from the position coordinates of each node of the base tire model 42. It is a gathering of. Further, the composite tire model creation unit 32 creates a composite vector for each node by multiplying the obtained plurality of tire base vectors by weighting coefficients α ₁ to α _N and adding them. The composite tire model creation unit 32 creates a composite tire model by giving this composite vector to each node of the reference tire model 40 as a displacement vector. That is, it is preferable that the synthetic tire model creation unit 32 creates a synthetic tire model by linear addition, that is, weighted addition, of tire base vectors of a plurality of base tire models 42. At this time, set values are used for the weighting coefficients α ₁ to α _N. When setting the values of the weighting coefficients α ₁ to α _N , for example, the values may be set by changing the level according to an experimental design such as the Monte Carlo method, the Latin hypersquare method, or the quasi-random number method. The value may be set by changing the level using an orthogonal table. The values of the weighting factors α ₁ to α _N are determined by the control / management unit 34. It is preferable that the sum of the values of the weighting coefficients α ₁ to α _N is always set to 1.

When producing the synthetic tire model, the synthetic tire model creating unit 32 sets the number of cord material ends and the inclination angle of the cord material (for example, in the direction in which the cord material extends with respect to the tire circumferential direction). It is preferable to change the inclination angle) from the number of ends of the cord material set in the reference tire model 40 and the inclination angle of the cord material according to the deformed shape from the reference tire model 40. The number of ends of the cord material is the number of cord materials per unit length of the cord material in a direction orthogonal to the extending direction of the cord material. Thereby, the physical quantity of the tire characteristic calculated from the simulation calculation mentioned later can be brought close to the physical quantity of the actual tire characteristic of the tire.
The reason for changing the number of ends of the cord material and the inclination angle of the cord material is as follows. When green tires are manufactured at the stage of the tire manufacturing process, cord materials having the same number of ends and the same inclination angle are commonly used regardless of whether the tires have different cross-sectional shapes. For this reason, when the tire cross-sectional shape changes, in an actual tire, the number of ends of the cord material and the inclination angle change according to the change in the tire cross-sectional shape. In order to reproduce such a change, it is preferable to change the number of ends of the cord material and the inclination angle of the cord material according to the deformed shape from the reference tire model 40. For example, when increasing the tire outer diameter, the belt layer is changed to reduce the inclination angle with respect to the tire circumferential direction. Such changes are preferably changed depending on the location. That is, it is preferable to change the number of ends and the inclination angle so as to have a distribution.

The synthetic tire model creation unit 32 creates a synthetic tire model by linearly adding the tire base vectors for each base tire model 42. The composite tire model creation unit 32 creates a position coordinate value that is position information of each node for each base tire model 42. It is also preferable to create a synthetic tire model by multiplying and adding weighting coefficients α ₁ to α _N. Even in this case, it is preferable that the sum of the values of the weighting coefficients α ₁ to α _N is always set to 1.
Information on a plurality of synthetic tire models created in this way is stored in the storage unit 20.

In the above-described embodiment, one reference tire model is created, but the reference tire model creation unit 26 creates a reference tire model group in which at least one of the tire outer shape, the tire size, and the tire structure is different. May be. At this time, using each of the created templates for each of the created reference tire model groups, according to the number of templates, repeatedly creating a base tire and determining whether N base tire models have been created. It is preferable to create a plurality of synthetic tire models. That is, it is preferable to create a plurality of synthetic tire models by using a template for each of the reference tire models having at least one of the tire outer shape, the tire size, and the tire structure. This makes it possible to distinguish between the tire outer shape, tire size, or tire structure, and the characteristics of a common tire cross-sectional shape (for example, the sidewall portion protrudes outward, the tread shoulder portion is rounded, and the tread portion tire. It is possible to efficiently create a base tire model having a cross-sectional shape with a small radius of curvature.

When the composite tire model creation unit 32 creates a plurality of composite tire models, the control / management unit 34 changes the values of the weighting coefficients α ₁ to α _N used for the above-described weighted addition. The values of the weighting factors α ₁ to α _N may be changed continuously within a predetermined domain or may be changed discretely. The control / management unit 34 assigns a level to the weighting coefficients α ₁ to α _N according to a known experimental design method, and assigns this value to each of the synthetic tire models 46, so that a plurality (M Pieces: M is a natural number).

The simulation calculation unit 36 uses the plurality of (M times) synthetic tire models created by the synthetic tire model creation unit 32 to perform a simulation calculation that reproduces the behavior of the tire to obtain tire characteristics (step S6). The simulation calculation is performed for each created synthetic tire model. Therefore, the simulation calculation is performed by the number of synthetic tire models created. The simulation calculation unit 36 calculates a physical quantity of the tire characteristic of the synthetic tire model by performing a simulation for obtaining the tire characteristic. Tire characteristics include, for example, tire rolling resistance, tread wear life, tread uneven wear, vibration ride performance, tire noise, belt durability, tire lateral spring constant (lateral stiffness) or longitudinal spring constant (longitudinal stiffness). ) Etc.

The simulation calculation unit 36 is a physical quantity of tire characteristics set in advance by an input operation device such as the mouse / keyboard 18, such as a natural frequency, a longitudinal spring constant, a lateral spring constant, a longitudinal spring constant, a rolling resistance, and an interlaminar shear between belts. A physical quantity such as a strain, a predicted wear value, or a contact pressure value when the tire contacts the ground is calculated by numerical calculation. These specific calculations are well-known methods and will not be described. The physical quantity of the tire characteristic that is the calculation result is stored in the storage unit 20.

The determining unit 38 optimizes the tire cross-sectional shape based on the calculation result of the tire characteristics obtained by the simulation calculating unit 36 for each created synthetic tire model (step S8). Specifically, the determination unit 38 determines the design space of the tire cross-sectional shape by a response surface function using a surface approximation function. This response surface function uses the weighting coefficient as a design variable. That is, the response surface function is a physical characteristic of tire characteristics expressed using a curved surface approximation function with the weighting coefficients α ₁ to α _N as design variables. For example, by defining six weighting factors, one tire cross-sectional shape is determined, and one physical quantity is obtained by a curved surface approximation function. Here, examples of the curved surface approximation function include Chebyshev's orthogonal polynomial, n-order polynomial, radial basis function method (RBF), Kriging method, and the like. Then, the determination unit 38 searches for an optimized tire cross-sectional shape based on the determined response surface function using, for example, an expressive method such as a multi-purpose genetic algorithm or a mathematical programming method such as a gradient method. That is, the determination unit 38 uses the weighting coefficients α ₁ to α _N as design variables, the physical quantity of tire characteristics as an objective function, and changes the value of the design variable so as to satisfy the set condition, thereby the objective function Is searched for the tire cross-sectional shape of the synthetic tire model having the physical quantity of the synthetic tire model that satisfies a preset condition. The preset condition is, for example, a range having an upper limit and a lower limit of a physical quantity representing tire characteristics, a minimum value of physical quantities representing tire characteristics, or a maximum value of physical quantities representing tire characteristics. As described above, the determination unit 38 performs the simulation calculation for obtaining the tire characteristics using a plurality of synthetic tire models, thereby finding an optimized tire cross-sectional shape in which the physical quantity of the tire characteristics satisfies a preset condition. .
Since the determination unit 38 changes the values of the weighting factors α ₁ to α _N to determine the optimum tire cross-sectional shape, it extracts the values of the weighting factors α ₁ to α _N that satisfy the condition of the physical quantity of the tire characteristics. Thus, the optimized tire cross-sectional shape can be easily determined.

In addition, the obtained information on the optimized tire cross-sectional shape is output to the output device 20, and is also sent to a CAD system or the like that creates a tire vulcanization mold (not shown). Alternatively, the obtained optimized tire cross-sectional shape is stored in the storage unit 20 as information on the tire cross-sectional shape at the time of tire deflation or as information on the cross-sectional shape of the in-mold tire, and further, a hard disk, a recording medium, etc. (not shown) To be recorded.

In this embodiment, the synthetic tire model creation unit 32 creates a plurality of synthetic tire models used for simulation calculation at once using the weighting coefficients α ₁ to α _N determined by the control / management unit 34. In the form, the optimized tire cross-sectional shape may be extracted using an evolutionary calculation method such as a multi-purpose genetic algorithm. That is, in the present embodiment, an evolutionary calculation method such as a multi-purpose genetic algorithm is used so as to satisfy the condition in which the physical quantity of the tire characteristic is set according to the physical quantity of the tire characteristic obtained using the synthetic tire model. The optimized tire cross-sectional shape may be extracted while sequentially creating a synthetic tire model having a tire cross-sectional shape improved by use.
In this way, while the synthetic tire model having the improved tire cross-sectional shape is sequentially created in the synthetic tire model creation unit 32, the determination unit 34 extracts the optimized tire cross-sectional shape and a plurality of composites created at one time. It is also preferable to provide both a method of determining a response surface function from a physical quantity of tire characteristics of a tire model and extracting an optimized tire cross-sectional shape. In this case, the simulation apparatus 10 may be configured so that the operator selects one of the two methods in advance. The extracted optimized tire cross-sectional shape is not limited to one. For example, when there are a plurality of objective functions (physical quantities of tire characteristics), all or part of the Pareto solution may be extracted.

Thus, the determination unit 38 can extract the optimized tire cross-sectional shape, but it is preferable to display the search process for the optimized tire cross-sectional shape on the display 16. That is, the determination unit 38 visualizes the relationship between the weighting coefficients α ₁ to α _N or the characteristic amount characterizing the tire cross-sectional shape obtained when finding the optimized tire cross-sectional shape and the physical quantity of the tire characteristic, and displays the screen. It is preferable to display. For example, a scatter diagram, graph, self-organizing map, or decision tree is displayed on the screen. The feature amount includes the position information of the point having the maximum tire width, the position information of the division position of the sector mold and the side mold (for example, the end portion in the tire cross-sectional width direction on the tire outer peripheral surface in the arrangement region of the tread rubber). Position information), tire outer diameter, or radius of curvature of the tread center portion is preferably included.
In this way, visualization makes the relationship between the physical quantity of tire characteristics and the values of the weighting coefficients α ₁ to α _N or the above-mentioned feature quantity clear, and can be useful information for tire development.

This embodiment also includes a non-transitory computer readable medium that records a program that executes a method of creating a tire model of a pneumatic tire from a reference tire model using a computer.
In this case, the method
Let the computer create a plurality of templates representing the distribution of the amount of change for changing the outer shape from the reference tire model 40,
Let the computer create the reference tire model 40,
Using the reference tire model 40 and one of the templates, the computer creates a base tire model 42 having an outer shape in which the outer shape of the reference tire model 40 is changed,
Using the template representing the variation distribution different from the variation distribution already used for creating the base tire model 42 among the templates, the base having a different external shape from the base tire model 42 already created. Causing the tire model 42 to be repeatedly created,
And causing the computer to create a plurality of synthetic tire models having an outer shape different from the outer shape of the reference tire model 40 by combining the plurality of created base tire models 42.

The tire model creation method, tire model creation device, tire simulation method, and non-transitory computer-readable medium of the present invention have been described above in detail, but the present invention is not limited to the above-described embodiment. Of course, various improvements and modifications may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Simulation apparatus 12 Computer main body part 14 Printer 16 Display 18 Mouse keyboard 20 Memory | storage part 22 CPU
24 analysis processing unit 26 reference tire model creation unit 28 template creation unit 30 base tire model creation unit 32 synthetic tire model creation unit 34 control / management unit 36 simulation calculation unit 38 decision unit 40

reference tire models

41 and 43 outer shape contour line 42 Base tire model

Claims

A method of creating a tire model of a pneumatic tire from a reference tire model using a computer,
A first step of creating a plurality of templates representing a distribution of a change amount for changing an outer shape from a reference tire model by a computer;
A second step of creating the reference tire model by the computer;
A third step of creating a base tire model having an outer shape in which an outer shape of the reference tire model is changed by the computer using the reference tire model and one of the templates;
A base tire model having a different external shape from a base tire model that has already been created using a template that represents a distribution of the amount of change different from the distribution of the amount of change already used to create the base tire model. A fourth step of creating at least one of
By combining the plurality of base tire models created in the third step and the fourth step by the computer, the plurality of base tire models have an outer shape different from the outer shape of the reference tire model, and the outer shapes are different from each other. A tire model creation method comprising: a fifth step of creating a synthetic tire model.
In the second step, a reference tire model group in which at least one of a tire outer shape, a tire size, and a tire structure is different is created, and one of the reference model groups is the reference model,
Further, the plurality of synthetic tire models are created by repeating the third step and the fourth step according to the number of the templates, using the template for each of the created reference tire model groups. The method for creating a tire model according to claim 1.
In the third step and the fourth step, the computer acquires an outer contour line of the reference tire model or a carcass line of the reference tire model, and uses the outer contour line or the carcass line. The tire model creation method according to claim 1, wherein the base tire model is created by changing the template.
The reference tire model is a set of elements formed by a plurality of nodes and a plurality of sides connecting the plurality of nodes.
In the third step and the fourth step, the computer associates both ends of at least a part of the distribution of the change amount of the template with nodes on the contour line or the carcass line. Therefore, the region of the template is enlarged or reduced in accordance with the distance on the outer shape contour line between the nodes or the distance on the carcass line, and the outer shape of the reference tire model is obtained from the distribution of the enlarged and reduced regions. The base tire model is created by determining a moving amount of each node on the contour line or the carcass line to be moved and deforming the shape of the outer contour line or the carcass line. To create a new tire model.
The tire model creation method according to claim 4, wherein the region of the template is enlarged or reduced so that the region corresponds to at least one range of a tread portion, a side portion, and a bead portion of the reference tire model. .
The reference tire model is a model that can be subjected to calculation of shape deformation analysis by the computer. In the third step and the fourth step, the computer performs the outline shape contour line of the reference tire model or the 5. The base tire model is created by applying a forced displacement corresponding to the amount of movement to each node on a carcass line and performing the shape deformation analysis to deform the shape of the reference tire model. Or a method of creating a tire model according to 5.
In the fifth step, the computer creates a composite vector by weighting and adding a plurality of tire base vectors representing a difference between each of the plurality of base tire models and the shape of the reference tire model, and the composite The tire model creation method according to any one of claims 1 to 6, wherein the synthetic tire model is created by deforming the reference tire model based on a vector.
In the synthetic tire model, the number of ends of the cord material and the inclination angle of the cord material set in the synthetic tire model are calculated from the number of ends of the cord material and the inclination angle of the cord material set in the reference tire model. The method for creating a tire model according to any one of claims 1 to 7, wherein the tire model is changed according to a deformed shape from the tire model.
A tire characteristic of the synthetic tire model is obtained by performing a simulation reproducing the behavior of the tire using the synthetic tire model created by the tire model creation method according to any one of claims 1 to 8. A method for simulating a tire, comprising calculating a physical quantity of the tire.
A physical quantity of tire characteristics of the synthetic tire model is calculated by performing a simulation reproducing the behavior of the tire using the synthetic tire model created by the tire model creating method according to claim 7, The weighting coefficient used when weighting and adding the tire base vector is a design variable, the physical quantity calculated by the simulation is an objective function, and the design variable is set so that the objective function satisfies a preset condition. A method for simulating a tire, comprising the step of changing the value of.
11. The tire simulation method according to claim 10, wherein the computer visualizes and displays the relationship between the weighting coefficient value or the feature quantity representing the shape of the synthetic tire model and the physical quantity on the screen.
A non-transitory computer readable medium for recording a program for executing a method for creating a tire model of a pneumatic tire from a reference tire model using a computer,
The method
Let the computer create multiple templates that represent the distribution of the amount of change to change the outer shape from the reference tire model,
Let the computer create the reference tire model,
Using the one of the reference tire model and the template, the computer creates a base tire model having an outer shape in which the outer shape of the reference tire model is changed,
A base tire model having a different external shape from the base tire model that has already been created by using a template that represents a distribution of the amount of change different from the distribution of the amount of change already used to create the base tire model, among the templates. To repeatedly create
Including causing the computer to create a plurality of synthetic tire models having an outer shape different from the outer shape of the reference tire model by combining the plurality of base tire models that have been created. .
A tire model creation device for creating a tire model of a pneumatic tire from a reference tire model,
A reference tire model creation unit configured to create a reference tire model;
A template creation unit configured to create a plurality of templates representing a distribution of a change amount for changing the outer shape from the reference tire model;
A base tire model creation unit configured to create a base tire model having an outer shape in which an outer shape of the reference tire model is changed using one of the reference tire model and the template;
A template that controls the base tire model creation unit so as to repeat the creation of the base tire model, and represents a change amount distribution different from the change amount distribution already used for creating the base tire model among the templates. A control unit configured to control the base tire model creation unit so as to create at least one base tire model having a different external shape from the already created base tire model,
A composite tire model creation unit configured to create a plurality of composite tire models having a different external shape from the external shape of the reference tire model by combining a plurality of created base tire models And a tire model creating apparatus.