JP7091868B2 - Tire design method and tire manufacturing method - Google Patents

Description

The present invention relates to a method for designing a tire and a method for manufacturing a tire based on an optimization algorithm.

Patent Document 1 proposes a method for optimizing the shape of a tire by using a computer. In the method of Patent Document 1, the objective function (performance) is satisfied based on the process of setting a tire model divided by computer-analyzable elements based on the reference tire cross-sectional shape and the optimization algorithm. It includes the process of determining the shape of the tire.

Japanese Unexamined Patent Publication No. 2017-091007

The tire model of Patent Document 1 is set based on the cross-sectional shape of a commercially available tire or the like that has been vulcanized and molded. Therefore, the method of Patent Document 1 separately requires the design of a raw tire before vulcanization in order to actually obtain an optimized tire. Therefore, in the method of Patent Document 1, there is room for improvement in efficiently designing a tire.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a method for efficiently designing a tire and a method for manufacturing the tire.

The present invention is a method for designing a tire manufactured through a step of molding a raw tire and a step of vulverizing the raw tire, and a model of the raw tire with a finite number of elements on the computer. A tire model in which the raw tire model is set by setting the raw tire model and the computer deforms the raw tire model based on predetermined squeezing conditions to provide the tire shape after smelting. The brewing simulation process for acquiring the tire model, the process for the computer to calculate the deformation of the tire model based on the predetermined test conditions, and the process for acquiring the physical quantity related to the predetermined tire performance from the calculation, and the computer. However, the objective function is used as the objective function, the predetermined design factor of the raw tire model is used as the design variable, and the objective function is optimized based on the optimization algorithm under predetermined constraint conditions. It is characterized by including a step of obtaining an optimum solution of a design factor and a step of designing a tire based on the raw tire model obtained by using the optimum solution.

In the tire design method according to the present invention, the raw tire model is set by joining a plurality of tire member models to each other, and the design factor is associated with at least one shape of the plurality of tire member models. It may have been.

In the tire design method according to the present invention, at least one of the plurality of tire member models may be a tread rubber model that models a tread rubber.

In the tire design method according to the present invention, at least one of the plurality of tire member models may be a sidewall rubber model that models a sidewall rubber.

In the tire design method according to the present invention, the raw tire model is set by joining a plurality of tire member models to each other, and the plurality of tire member models are fibrous material models that model fibrous materials. Including, the design factor may be associated with the angle of the fibers of the fiber material model.

In the tire design method according to the present invention, the fiber material model may be a carcass model that models a carcass.

In the tire design method according to the present invention, the fiber material model may be a belt model that models a belt.

In the tire design method according to the present invention, the constraint may include the weight of the plurality of tire member models.

In the tire design method according to the present invention, in the raw tire model setting step, the step of defining the plurality of tire member models in the computer and the plurality of tire member models are joined to each other to form the raw tire model. It may include a step of defining.

In the tire design method according to the present invention, the physical quantity may include at least one of the spring constant of the tire model, parameters related to the ground contact shape, rolling resistance value, cornering power and mass.

The present invention comprises a step of molding a raw tire based on the raw tire model using the optimum solution obtained by using the method according to any one of claims 1 to 10, and vulcanizing the raw tire. It is characterized by including a molding process.

The tire design method of the present invention is based on a raw tire model setting step of setting a raw tire model in which a raw tire is modeled with a finite number of elements on a computer, and the computer based on predetermined vulcanization conditions. It includes a vulcanization simulation step of deforming the raw tire model to acquire a tire model having a tire shape after vulcanization.

The tire design method of the present invention includes a step in which the computer performs a deformation calculation of the tire model based on a predetermined test condition, and obtains a predetermined physical quantity related to the tire performance from the calculation. .. Further, in the tire design method of the present invention, the computer uses the physical quantity as an objective function and a predetermined design factor of the raw tire model as a design variable, and optimizes the tire under predetermined constraints. It includes a step of finding an optimum solution of the design factor for optimizing the objective function based on an algorithm, and a step of designing a tire based on the raw tire model obtained by using the optimum solution.

The design method of the present invention can obtain the optimum solution of the design factor of the raw tire model before vulcanization for the tire model for which the objective function is optimized. Therefore, the design method of the present invention can efficiently design a tire having the excellent tire performance.

It is a perspective view which shows an example of the computer 1 for executing the tire design method and the tire manufacturing method. It is sectional drawing which shows an example of a raw tire. (A) is a partial perspective view showing an example of a carcass, and (b) is a partial perspective view showing an example of an inner belt and an outer belt. (A) and (b) are sectional views explaining an example of the process of molding a raw tire. It is sectional drawing explaining an example of the process of vulcanizing and molding a raw tire. It is a flowchart which shows an example of the processing procedure of the tire design method and the tire manufacturing method. It is a flowchart which shows an example of the processing procedure of the raw tire model setting process. It is a conceptual diagram which shows an example of a tire member model. It is a conceptual diagram which shows an example of a carcass model. It is a conceptual diagram which shows an example of an inner belt model and an outer belt model. It is a conceptual diagram which shows an example of the 1st junction model, the 2nd junction model, and the tread ring model. It is a conceptual diagram which shows an example of the casing model which bulged outward in the radial direction. It is a conceptual diagram which shows an example of a deformed tread ring model. It is a conceptual diagram which shows an example of a raw tire model. It is a conceptual diagram which shows an example of the raw tire model arranged inside the mold model. It is a conceptual diagram which shows an example of a tire model and a road surface model. (A) is a cross-sectional view of a raw tire model before the optimization of the embodiment, and (b) is a cross-sectional view of the raw tire model after the optimization of the embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the tire design method of the present embodiment (hereinafter, may be simply referred to as "design method"), the tire manufactured through the steps of molding the raw tire and the vulcanization molding of the raw tire is the computer 1. Designed using. Further, in the tire manufacturing method of the present embodiment (hereinafter, may be simply referred to as “manufacturing method”), the tire is manufactured based on the optimum solution obtained by the tire design method.

FIG. 1 is a perspective view showing an example of a computer 1 for executing a tire design method and a tire manufacturing 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 an arithmetic 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 stores in advance a processing procedure (program) for executing the design method and the manufacturing method of the present embodiment.

FIG. 2 is a cross-sectional view showing an example of a raw tire. The raw tire 2 is formed by stacking a plurality of tire members 11 on each other. The tire member 11 includes a rubber member 3 and a fiber material 4. In the present embodiment, a raw tire 2 having an SOT (sidewall over tread) structure to which the sidewall rubber 3b is joined so as to cover the outer end portion of the tread rubber 3a in the tire axial direction from the outside in the tire axial direction is exemplified. However, it is not limited to such an embodiment. For example, a raw tire 2 having a TOS (tread over sidewall) structure may be used in which the outer end portion of the sidewall rubber 3b in the tire radial direction is covered with the inner surface of the tread rubber 3a in the tire radial direction.

The rubber member 3 includes a tread rubber 3a, a sidewall rubber 3b, a clinch rubber 3c, a bead apex rubber 3d, an inner liner rubber 3e, a bead core 3f, a covering rubber 3j, and a cushion rubber 3k. On the other hand, the fiber material 4 includes a carcass 4a and a belt 4b. The belt 4b of the present embodiment includes an inner belt 4c and an outer belt 4d.

The tread rubber 3a is arranged on the outside of the outer belt 4d in the tread portion 2a. The sidewall rubber 3b is arranged on the outside of the carcass 4a in the sidewall portion 2b. The clinch rubber 3c is fixed to the inside of the sidewall rubber 3b in the radial direction. The bead apex rubber 3d extends outward from the bead core 3f in the radial direction of the tire. The inner liner rubber 3e is arranged on the inner surface of the carcass 4a.

The bead core 3f is formed, for example, by spirally winding a bead wire made of steel to form a substantially rectangular cross section and covering it with unvulcanized rubber. The covering rubber 3j covers both ends of the inner belt 4c and both ends of the outer belt 4d, respectively. The cushion rubber 3k is arranged outside the carcass 4a in the buttress portion of the raw tire 2.

The carcass 4a extends from the tread portion 2a through the sidewall portion 2b to the bead core 3f of the bead portion 2c. The belt 4b (inner belt 4c and outer belt 4d) is arranged outside the carcass 4a in the radial direction of the tire and inside the tread rubber 3a.

FIG. 3A is a partial perspective view showing an example of the carcass 4a. FIG. 3B is a partial perspective view showing an example of the inner belt 4c and the outer belt 4d. As shown in FIGS. 3A and 3B, the fiber material 4 (carcus 4a and belt 4b) is composed of the fiber 12 and the unvulcanized topping rubber 13.

As shown in FIG. 3A, the carcass 4a is a fiber 12 arranged at an angle δ of, for example, 65 to 90 degrees with respect to the tire equator C (hereinafter, may be simply referred to as “carcus code 12a”). And a topping rubber 13 that covers the carcass cord 12a. On the other hand, as shown in FIG. 3B, the inner belt 4c and the outer belt 4d are the fibers 12 arranged at an angle φ of, for example, 10 to 40 degrees with respect to the tire circumferential direction (hereinafter, simply “belt cord”). It may be referred to as "12b") and a topping rubber 13 for covering the belt cord 12b.

4 (a) and 4 (b) are cross-sectional views illustrating an example of a process of molding a raw tire. As shown in FIG. 4A, in the step of molding the raw tire 2 of the present embodiment, first, the first joint 5 is placed on a cylindrical drum (not shown), as in the conventional molding step. And the second junction 6 is formed.

The first joint 5 is formed by forming an inner liner rubber 3e, a carcass 4a, a clinch rubber 3c, a sidewall rubber 3b, and a cushion rubber 3k on the outer peripheral surface of the drum (not shown) in a cylindrical shape and joins them to each other. Is formed by. On the other hand, the second bonded body 6 is formed by forming the bead core 3f and the bead apex rubber 3d into a cylindrical shape and joining them to each other. By joining these first joints 5 and second joints 6, a cylindrical casing 7 is formed.

Next, in the step of forming the raw tire, for example, a drum having a diameter larger than that of the drum (not shown) forming the first joint 5 and the second joint 6 (not shown) has a cylindrical tread ring. 8 is formed. The tread ring 8 is formed by forming a tread rubber 3a, an inner belt 4c, and an outer belt 4d into a cylindrical shape on the outer peripheral surface (not shown) of the drum and joining them to each other.

Next, in the step of forming the raw tire, the casing 7 expands in a toroid shape by applying high pressure air P1 while reducing the axial distance of the bead cores 3f and 3f by the bead holding portion 9 that grips the bead core 3f. It is put out (shaping). Further, on the outer peripheral surface of the casing 7, the inner peripheral surface of the tread ring 8 that has been previously made to stand by on the outer side in the radial direction is attached. Then, as shown in FIG. 4B, the stitching roller (not shown) is pressed against the outer peripheral surface of the tread ring 8, so that the outer peripheral surface of the casing 7 and the inner peripheral surface of the tread ring 8 are in close contact with each other. Will be done.

Next, in the step of forming the raw tire, in the casing 7 to which the high pressure air P1 is applied, the protruding portion 7p (including the sidewall rubber 3b and the clinch rubber 3c) protruding outside the bead core 3f in the tire axial direction protrudes. Due to the expansion of the bladder (not shown) arranged inward in the radial direction of the portion 7p, the bladder is wound around the bead core 3f. As a result, the raw tires 2 in which the plurality of tire members 11 are formed into a cylindrical shape and joined to each other are formed.

FIG. 5 is a cross-sectional view illustrating an example of a process of vulcanizing and molding a raw tire. In the vulcanization molding step, first, the raw tire 2 is put into the vulcanization die 14 in the same manner as in the conventional tire manufacturing method. Next, in the step of vulcanization molding, the raw tire 2 put into the vulcanization die 14 is pressed against the molding surface 14s of the vulcanization die 14 and heated by the bladder 15 made of an elastic body. As a result, the raw tire 2 is vulcanized and molded, and the tire 20 is manufactured.

By the way, Patent Document 1 proposes a method for optimizing the shape of a tire by using a computer. In the method of Patent Document 1, the shape of a tire (tire model) that satisfies the objective function (tire performance) is obtained while deforming the tire model divided by elements that can be analyzed by a computer based on the reference tire cross-sectional shape. Includes the required process.

In the method of Patent Document 1, a tire model is set based on the cross-sectional shape of a commercially available tire or the like that has been vulcanized and molded. Therefore, in order to actually obtain an optimized tire, it is necessary to separately design the raw tire 2 (shown in FIG. 2) before vulcanization.

In the design of the raw tire 2, for example, the parameters required for molding the raw tire 2 are determined. The parameters include, for example, the shape (dimensions) of each tire member 11 and the bead set width (bead set position) between the bead cores 3f and 3f in the process of molding the raw tire 2, as shown in FIG. 4A. W2 (shown in FIG. 4B) and radial height H1 of the bead apex rubber 3d (shown in FIG. 4A) are included. Further, the parameters include, for example, the position of the inner end of the sidewall rubber 3b in the tire axial direction, the position of the inner end of the clinch rubber 3c in the tire axial direction, and the angles δ and φ of the fibers 12 of the fiber material 4 (FIG. 3). (A) and (shown in (b)) are included. Since these parameters are related to, for example, the shape of the sidewall portion of the raw tire 2 in the step of molding the raw tire 2 shown in FIG. 4 (b), the raw tire 2 (shown in FIG. 2) and , The shape of the tire 20 (shown in FIG. 5) obtained by vulcanizing the raw tire 2 is greatly affected.

In the conventional design of the raw tire 2, the above parameters are set based on trial and error by the designer and empirical rules so far. Therefore, in the method of Patent Document 1, there is room for improvement in efficiently designing the tire 20.

In the design method of the present embodiment, the design factors (for example, the above parameters) of the raw tire model before vulcanization are used for the tire model for which the objective function (physical quantity related to tire performance) is optimized based on the processing procedure described later. The optimum solution is required. As a result, in the design method, the design factor of the raw tire model can be directly obtained, so that the tire 20 satisfying the objective function (that is, having excellent tire performance) can be efficiently designed.

The optimum solution of the design factor is obtained based on the optimization algorithm using the computer 1. The optimization algorithm is for determining the optimum design factor (for example, the above parameters) that satisfies an arbitrary objective function under certain constraints. Examples of the optimization algorithm include a genetic algorithm (GA (Genetic Algorithm)), particle swarm optimization (PSO), and the like. Such an optimization algorithm is suitable for finding a wide-area optimum solution while preventing it from falling into a local solution. In the calculation method of the present embodiment, particle swarm optimization (PSO) having a relatively short calculation time is adopted, but a genetic algorithm (GA) or the like may be adopted.

In particle swarm optimization (PSO), a first generation containing multiple initial design factors (design variables) is created, the objective function of each design factor is obtained, and each design factor is set so as to approach the most preferable objective function. Optimization is performed by updating (changing generations). By using random numbers to update each design variable, the optimum conditions can be searched for over a wide area. Details of particle swarm optimization (PSO) are described in various literatures such as IEICE Fundamentals Review (Institute of Electronics, Information and Communication Engineers) Vol.5 No.2, August 2011 "Particle Swarm Optimization and Nonlinear Systems". Has been done.

FIG. 6 is a flowchart showing an example of a processing procedure of a tire design method and a tire manufacturing method. In the design method of the present embodiment, first, the objective function, the design factor, and the constraint conditions are input to the computer 1 (step S1).

As the objective function, for example, a physical quantity related to tire performance is appropriately set according to the performance required for the tire. Examples of physical quantities set as objective functions are the spring constant of the tire model, the parameters related to the ground contact shape of the tire model (hereinafter, may be simply referred to as "ground contact parameters"), the rolling resistance value of the tire model, and the tire model. Includes cornering power and tire model mass. In the present embodiment, at least one of the above physical quantities is set as an objective function.

The objective function of the spring constant can be defined as appropriate. The objective function of the spring constant of the present embodiment includes an objective function of the vertical spring constant and an objective function of the horizontal spring constant.

The objective function of the vertical spring constant is a value obtained by dividing the absolute value of the difference between the vertical spring constant of the tire model that can be acquired in the physical quantity acquisition step S5 described later and the predetermined target vertical spring constant by the target vertical spring constant. (Hereinafter, it may be simply referred to as "vertical spring constant error".). On the other hand, the objective function of the lateral spring constant divides the absolute value of the difference between the lateral spring constant of the tire model that can be acquired in the physical quantity acquisition step S5 described later and the predetermined target lateral spring constant by the target lateral spring constant. (Hereinafter, it may be simply referred to as "horizontal spring constant error"). The objective function of these vertical spring constants (vertical spring constant error) and the objective function of the lateral spring constant (horizontal spring constant error) are such that the smaller the numerical value, the closer to the target vertical spring constant and the target lateral spring constant. Can be shown. The target vertical spring constant and the target horizontal spring constant can be appropriately defined based on, for example, the type of tire (including the category and the tire size).

The objective function of the grounding parameter can be defined as appropriate. The objective function of the grounding parameter of the present embodiment includes the objective function of the circumferential grounding parameter and the objective function of the axial grounding parameter.

The objective function of the circumferential contact parameter is defined by the absolute value of the difference between the contact length in the tire circumferential direction of the tire model that can be acquired in the physical quantity acquisition step S5 described later and the predetermined target contact length in the tire circumferential direction. To. On the other hand, the objective function of the axial contact parameter is an absolute value of the difference between the contact length in the tire axial direction of the tire model that can be acquired in the physical quantity acquisition step S5 described later and the predetermined target contact length in the tire axial direction. Defined. It can be shown that the smaller the numerical value, the closer the objective function of these circumferential grounding parameters and the objective function of the axial grounding parameter are to the target grounding shape. The target contact length in the tire circumferential direction and the target contact length in the tire axial direction can be appropriately defined based on, for example, the type of tire (including the category and the tire size).

The objective function of the rolling resistance value can be appropriately defined. The objective function of the rolling resistance value of the present embodiment is defined as the average value of the rolling resistance values of the tire model that can be acquired in the physical quantity acquisition step S5 described later. It can be shown that the smaller the objective function of the rolling resistance value is, the better it is.

The objective function of cornering power can be defined as appropriate. The objective function of the cornering power is defined as the average value of the cornering power of the tire model that can be acquired in the physical quantity acquisition step S5 described later. It can be shown that the larger the value, the better the objective function of such cornering power.

The objective function of mass can be defined as appropriate. The objective function of mass is a value obtained by dividing the difference between a predetermined reference mass and the mass of the tire model that can be acquired in the physical quantity acquisition step S5 described later by the reference mass (hereinafter, simply referred to as "mass reduction rate"). May be defined as). The larger the value, the better the rate of decrease in mass. The reference mass can be appropriately defined based on, for example, the type of tire (including the category and the tire size).

In step S1 of the present embodiment, the objective function of the spring constant and the objective function of the mass are set. The objective function is not limited to the above physical quantity, and other physical quantities may be set. The objective function is input to computer 1.

Next, the design factor can be appropriately set according to, for example, the type of tire (including the category and the tire size). The design factor of the present embodiment is associated with, for example, the parameters necessary for forming the above-mentioned raw tire 2.

Among the above-mentioned parameters, the design factors of the present embodiment include the bead set width W2 (shown in FIG. 4 (b)) and the height H1 in the radial direction of the bead apex rubber 3d (bead apex rubber model described later) (FIG. 4). 4 (a)) and at least one shape of the tire member 11 (tire member model described later) are associated with each other. The shape of the tire member 11 (dimensions for specifying the shape, etc.) associated with the design factor can be appropriately selected. In this embodiment, the thickness W3 of the sidewall rubber 3b (shown in FIG. 4B) and the thickness W4 of the clinch rubber 3c (shown in FIG. 4B) are associated with the design factors. These design factors are stored in the computer 1.

The constraint condition is a condition (design standard) that must be satisfied in the molding of the raw tire 2 shown in FIGS. 4A and 4B. Such constraint conditions can be appropriately set based on, for example, a molding device for the raw tire 2 (not shown). As the constraint condition of this embodiment, the settable range of the bead set width W2 (shown in FIG. 4B) is set. The settable range of such a bead set width W2 is determined based on, for example, the settable range of the bead holding portion 9. The constraint condition is stored in the computer 1.

Next, in the design method of the present embodiment, the initial values of the design variables of the raw tire model are input to the computer 1 (step S2). The initial values of the design variables are used to set the raw tire model in the raw tire model setting step S3 described later.

The initial values of the design variables of this embodiment are the design factors input in step S1 (in this embodiment, the bead set width W2, the radial height H1 of the bead apex rubber 3d, and the thickness of the sidewall rubber 3b). The initial values of W3 and the thickness W4) of the clinch rubber 3c are included. The initial value of the design variable is set so as to satisfy the constraint condition (in this embodiment, the settable range of the bead set width W2). The initial value of the design variable is appropriately set based on the tire type (including the category and the tire size) and the like. The initial value of the design variable may be set randomly based on a random number if the constraint condition is satisfied.

In the present embodiment, in order to set a plurality of raw tire models, a plurality of design variables having at least one initial value of the design factors different from each other are set. Thereby, in the raw tire model setting step S3 described later, a plurality of raw tire models and tire models having different shapes can be set. The initial value of the design variable is stored in the computer 1.

Next, in the design method of the present embodiment, a raw tire model in which the raw tire 2 is modeled with a finite number of elements is set in the computer 1 (raw tire model setting step S3). FIG. 7 is a flowchart showing an example of the processing procedure of the raw tire model setting step S3.

In the raw tire model setting step S3 of the present embodiment, first, a plurality of tire member models are defined in the computer (step S31). FIG. 8 is a conceptual diagram showing an example of the tire member model 19.

In step S31, first, a plurality of tire member models 19 are set by discretizing the tire member 11 with a finite number of elements F (i) (i = 1, 2, ...). The discrete tire member 11 has an initial value of a design variable input in step S2 and a predetermined design parameter other than the design variable (for example, an initial value of a shape (dimension) of each tire member 11). It is specified based on the initial values of the angles δ, φ, etc. of the fibers 12 of the fiber material 4. The tire member model 19 of the present embodiment includes a rubber member model 16 that models the rubber member 3 and a fiber material model 18 that models the fiber material 4.

The rubber member model 16 includes a tread rubber model 16a in which the tread rubber 3a (shown in FIG. 2) is discretized, a sidewall rubber model 16b in which the sidewall rubber 3b (shown in FIG. 2) is discretized, and a clinch rubber 3c (FIG. 2). 2) is included with the discretized clinch rubber model 16c. Further, the rubber member model 16 includes a bead apex rubber model 16d in which the bead apex rubber 3d (shown in FIG. 2) is discretized and an inner liner rubber model 16e in which the inner liner rubber 3e (shown in FIG. 2) is discretized. Includes. Further, the rubber member model 16 includes a bead core model 16f in which the bead core 3f (shown in FIG. 2) is discretized, a covering rubber model 16j in which the covering rubber 3j (shown in FIG. 2) is discretized, and a cushion rubber 3k (FIG. 2). Includes a discretized cushion rubber model 16k (shown in).

Radial height H1 of bead apex rubber model 16d (shown in FIG. 11), sidewall rubber model 16b thickness W3 (shown in FIG. 11), and clinch rubber model 16c thickness W4 (shown in FIG. 11). ) Is set based on the initial value of the design variable.

The element F (i) can be handled by a numerical analysis method. As the numerical analysis method, for example, a finite element method, a finite volume method, a difference method, or a boundary element method can be appropriately adopted. In this embodiment, the finite element method is adopted.

The element F (i) of the present embodiment is defined as a three-dimensional solid element. Further, each element F (i) has an element number, a node number 17, a coordinate value of the node 17, and a material property (for example, density, tensile rigidity, compressive rigidity, shear rigidity, bending rigidity, or torsional rigidity). Etc.) and other numerical data are defined.

The material properties of the parts that make up unvulcanized rubber are described, for example, in the literature (Hiroshi Harima, "Large deformation behavior of unvulcanized rubber under a constant elongation rate", Journal of the Society of Rheology, Japan, Society of Rheology, Japan, 1976, Vol. 4, p. 3-9) and literature (Chio Tozaki, 3 others, "Green Strength Index, Viscoelastic Handling of Yield Stress", Journal of the Japan Rubber Association, Japan Rubber Association , 1969, Vol. 42, No. 6, p.433-438) and the like. In this embodiment, the material properties of unvulcanized rubber are defined based on these documents.

The fiber material model 18 includes a carcass model 18a in which the carcass 4a (shown in FIG. 2) is discretized and a belt model 18b in which the belt 4b (shown in FIG. 2) is discretized. The belt model 18b includes an inner belt model 18c in which the inner belt 4c (shown in FIG. 2) is discretized and an outer belt model 18d in which the outer belt 4d (shown in FIG. 2) is discretized.

FIG. 9 is a conceptual diagram showing an example of the carcass model 18a. FIG. 10 is a conceptual diagram showing an example of the inner belt model 18c and the outer belt model 18d. As shown in FIGS. 9 and 10, the fiber material model 18 uses a finite number of elements G (i) (i = 1, 2, ...) To connect the fibers 12 shown in FIGS. 3 (a) and 3 (b). It includes a discretized fiber model 21 and a topping rubber model 22 in which the topping rubbers 13 shown in FIGS. 3 (a) and 3 (b) are discretized by a finite number of elements F (i). As the element F (i), the same element F (i) as the element F (i) of the rubber member model 16 shown in FIG. 8 is adopted.

The element G (i) of the fiber model 21 of this embodiment is defined as a beam element. The beam element is a linearly defined one-dimensional element. Unlike a two-dimensional shell element or a three-dimensional solid element, such a beam element can calculate longitudinal tension or compression acting on each fiber 12 (shown in FIG. 3A). The element of the fiber model 21 may be defined as a shell element in which the anisotropy of the rigidity of the cord is defined. Such shell elements help model the fiber model 21 in a short period of time.

As the numerical analysis method of the element G (i), the same method as that of the element F (i) is adopted. The element G (i) includes the element number, the coordinate value of the node 23, and the material properties (for example, density, tensile rigidity, compressive rigidity, shear rigidity, bending rigidity) of the fiber 12 (shown in FIG. 3A). Numerical data including torsional rigidity, elastic modulus, or thermal expansion coefficient along the longitudinal direction of the fiber 12) are defined.

The fiber model 21 includes a carcass code model 21a that models a carcass code 12a (shown in FIG. 3A) and a belt code model 21b that models a belt code 12b (shown in FIG. 3B). I'm out.

As shown in FIG. 9, the carcass code model 21a is set by assigning elements G (i) along the carcass code 12a based on the array of carcass codes 12a shown in FIG. 3 (a). .. Thereby, the carcass code model 21a can accurately define the carcass code 12a arranged at the angle δ. The carcass model 18a is defined by integrating the carcass code model 21a and the topping rubber model 22.

As shown in FIG. 10, the belt code model 21b is set by assigning elements G (i) along the belt code 12b based on the arrangement of the belt code 12b shown in FIG. 3 (b). .. Thereby, the belt cord model 21b can accurately define the belt cords 12b arranged at an angle φ. The belt model 18b (inner belt model 18c and outer belt model 18d) is defined by integrating the belt cord model 21b and the topping rubber model 22.

A plurality of tire member models 19 having different shapes for each of the initial values of the plurality of design variables set in step S2 (in this embodiment, the bead apex rubber model 16d, the sidewall rubber model 16b, and the clinch rubber model 16c). ) Is set. Each tire member model 19 is stored in the computer 1.

Next, in the raw tire model setting step S3 of the present embodiment, the raw tire model 30 is defined by joining a plurality of tire member models 19 to each other (step S32). FIG. 11 is a conceptual diagram showing an example of the first junction model 25, the second junction model 26, and the tread ring model 28. In step S32, first, the first joint model 25, the second joint model 26, and the tread ring model 28 are set.

The first junction model 25 is a model of the first junction 5 (shown in FIG. 4A). The first joined body model 25 is defined by arranging (joining) the inner liner rubber model 16e, the carcass model 18a, the clinch rubber model 16c, the sidewall rubber model 16b, and the cushion rubber model 16k in an overlapping manner. The arrangement of the models 16e, 18a, 16c, 16b and 16k is carried out based on the initial values of the design variables input in step S2 and the design parameters other than the design variables. Boundary conditions are set between the models 16e, 18a, 16c, 16b and 16k to prevent relative movement.

The second junction model 26 is a model of the second junction 6 (shown in FIG. 4A). The second joined body model 26 is defined by superimposing (joining) the bead core model 16f and the bead apex rubber model 16d. The arrangement of the models 16f and 16d is carried out based on the initial values of the design variables input in step S2 and the design parameters other than the design variables. Boundary conditions are set between the models 16f and 16d to prevent relative movement.

The tread ring model 28 is a model of the tread ring 8 (shown in FIG. 4A). The tread ring model 28 is defined by superimposing (joining) the tread rubber model 16a, the inner belt model 18c, the outer belt model 18d, and the covering rubber model 16j. The arrangement of the models 16a, 18c, 18d and 16j is carried out based on the initial values of the design variables input in step S2 and the design parameters other than the design variables. Boundary conditions are set between the models 16a, 18c, 18d and 16j to prevent relative movement.

FIG. 12 is a conceptual diagram showing an example of a casing model 27 that bulges outward in the radial direction. Next, in step S32, the casing model 27 in which the first joint model 25 and the second joint model 26 are in close contact with each other is set, and the deformation calculation for expanding the casing model 27 outward in the tire radial direction is performed. ..

In step S32, the bead portions 27c and 27c are moved inward in the tire axial direction and the casing model 27 is expanded outward in the tire radial direction so as to reduce the distance between the bead portions 27c and 27c of the casing model 27 in the tire axial direction. The deformation calculation to be issued is performed. The distance in the tire axial direction after the bead portions 27c and 27c are moved is set based on the initial value of the design variable (initial value of the bead set width W2) input in the step S2.

The bulge of the casing model 27 is calculated based on the evenly distributed load w1 defined on the inner surface of the casing model 27. The evenly distributed load w1 is set based on the pressure of the high-pressure air that inflates the casing 7 of the raw tire 2 shown in FIG. 4A. The bulge of the casing model 27 allows the outer surface of the casing model 27 to come into contact with the inner surface of the tread ring model 28.

Such deformation calculation is performed in a minute time (unit time Tx (x)) based on the shapes of the elements F (i) and G (i) shown in FIGS. 8 to 10, the coefficient of thermal expansion, the material properties, and the like. = 0, 1, ...))). Such deformation calculation can be performed using commercially available finite element analysis application software such as LS-DYNA manufactured by JSOL.

Next, in step S32, the tread ring model 28 (shown in FIG. 12) is deformed toward the casing model 27. FIG. 13 is a conceptual diagram showing an example of the modified tread ring model 28.

The deformation of the tread ring model 28 is calculated based on the evenly distributed load w2 defined on the outer surface of the tread ring model 28. The evenly distributed load w2 is set based on the pressure of the stitching roller (not shown) that presses the outer peripheral surface of the tread ring 8 of the raw tire 2 shown in FIG. 4 (b). As a result, in step S32, the deformation calculation of the tread ring model 28 can be performed so that the inner surface of the tread ring model 28 follows the outer surface of the casing model 27.

Next, in step S32, the protruding portion 27p of the casing model 27 protruding outward in the tire axial direction from the bead core model 16f is wound around the bead core model 16f. The winding of the protruding portion 27p is carried out based on the evenly distributed load w3 defined on the inner surface of the protruding portion 27p. The evenly distributed load w3 is set based on the pressure of the bladder (not shown) that presses the inner surface of the protruding portion (not shown) of the raw tire 2 shown in FIG. 4 (b).

Next, in step S32, the close contact state is maintained so that the tire member models 19 do not separate from each other. The close contact state can be defined by setting a boundary condition for preventing relative movement on the contact surface of the tire member model 19. As a result, the raw tire model 30 is created. FIG. 14 is a conceptual diagram showing an example of the raw tire model 30.

As described above, in the raw tire model setting step S3, a plurality of tire member models 19 are joined to each other in the same manner as in the actual forming process of the raw tire 2 shown in FIGS. 4 (a) and 4 (b). The tire model 30 can be set. As a result, in the raw tire model setting step S3, the raw tire model 30 capable of accurately reproducing the raw tire 2 can be created.

In the raw tire model setting step S3 of the present embodiment, a plurality of raw tire models 30 having different shapes are set for each initial value of the plurality of design variables set in the step S2. The raw tire model 30 is stored in the computer 1.

Next, in the design method of the present embodiment, the computer 1 deforms the raw tire model 30 based on predetermined vulcanization conditions and acquires a tire model having the tire shape after vulcanization (). Vulcanization simulation step S4). FIG. 15 is a conceptual diagram showing an example of a raw tire model 30 arranged inside a mold model.

The vulcanization simulation step S4 is carried out based on, for example, the mold deformation step, the tire shape acquisition step, and the heat shrinkage step described in Japanese Patent Application Laid-Open No. 2016-004484. The vulcanization conditions can be appropriately set based on, for example, the above-mentioned publication. Further, the deformation calculation and the heat shrinkage calculation of the raw tire model 30 can be performed by using the above-mentioned finite element analysis application software.

In the vulcanization simulation step S4, the raw tire model 30 can be bulged outward in the radial direction by the bulging of the bladder model 46, and the raw tire model 30 can be pressed against the molding surface 45s of the mold model 45. As described above, in the vulcanization simulation step S4, the raw tire model 30 can be deformed based on the step of vulcanizing and molding the actual raw tire 2.

Further, in the vulcanization simulation step S4, the heat-shrinked tire model 40 is calculated based on the heat-shrinking step described in Japanese Patent Application Laid-Open No. 2016-004484. As a result, in the vulcanization simulation step S4, it is possible to acquire a tire model 40 capable of accurately reproducing the tire shape after vulcanization. The material properties of the rubber member after vulcanization are defined in the material properties of the element F (i) of the rubber member model 16 of the tire model 40.

In the vulcanization simulation step S4 of the present embodiment, a plurality of tire models 40 having the tire shape after vulcanization are acquired for each of the plurality of raw tire models 30 set in the raw tire model setting step S3. The series of processes in the vulcanization simulation step S4 can be performed using the above-mentioned finite element analysis application software. The tire model 40 is stored in the computer 1.

Next, in the design method of the present embodiment, the computer 1 calculates the deformation of the tire model 40 based on the predetermined test conditions, and acquires the physical quantity related to the predetermined tire performance from the deformation (physical quantity acquisition). Step S5). FIG. 16 is a conceptual diagram showing an example of a tire model 40 and a road surface model 35.

The test conditions can be appropriately set according to the objective function obtained by the design method. In this embodiment, since the objective function of the spring constant (vertical spring constant and lateral spring constant) and the objective function of mass are obtained, the load conditions (vertical load and lateral load) to be loaded on the tire model 40 are the test conditions. Is set as. When the objective function of the rolling resistance value and the objective function of the cornering power are obtained, the rolling conditions (running speed, slip angle, etc.) of the tire model 40 are set as test conditions.

In the physical quantity acquisition step S5 of the present embodiment, first, the road surface model 35 for contacting the tire model 40 is input to the computer 1. As shown in FIG. 16, the road surface model 35 of the present embodiment is exemplified as a model of a flat road (not shown), but the outer peripheral surface of a drum tester (not shown) formed in a cylindrical shape. May be modeled. In this embodiment, a finite number of elements H (i) (i = 1) that can be handled by a numerical analysis method (finite element method in this embodiment) based on information on a road surface (flat road in this embodiment). , 2, ...) to discretize. As a result, the road surface model 35 is set.

Next, in the physical quantity acquisition step S5 of the present embodiment, the computer 1 calculates the tire model 40 after the internal pressure filling. The tire model 40 after filling the internal pressure is set by, for example, constraining the bead portion of the tire model 40 and calculating the deformation of the tire model 40 based on the evenly distributed load corresponding to the internal pressure condition, as in the conventional simulation method. can do. The deformation calculation of the tire model 40 can be performed using the above-mentioned finite element analysis application software.

Next, in the physical quantity acquisition step S5 of the present embodiment, the tire model 40 is brought into contact with the road surface model 35, and the physical quantity related to the tire performance is calculated. In the present embodiment, based on the load condition (vertical load T) set as the test condition, the tire model 40 after the internal pressure is filled and the tire model 40 after the load is brought into contact with the road surface model 35 is obtained. As a result, the vertical spring constant of the tire model 40 can be obtained. Further, a lateral spring constant is obtained by setting a lateral load (not shown) on the tire model 40 after filling the internal pressure. Further, the mass can be obtained based on the material properties set for each element F (i) or the like of the tire model 40 before the internal pressure filling.

In the physical quantity acquisition step S5, the rolling resistance value and the rolling resistance value are obtained by rolling the tire model 40 after the load on the road surface model 35 based on predetermined rolling conditions (running speed, slip angle, etc.). , Cornering power can be calculated.

In the present embodiment, physical quantities related to tire performance are acquired for each of the plurality of tire models 40 acquired in the vulcanization simulation step S4. The acquired physical quantity is stored in the computer 1.

Next, in the design method of the present embodiment, it is determined whether or not the objective function is satisfied (step S6). In the step S6 of the present embodiment, first, the physical quantity calculated for each tire model 40 in the physical quantity acquisition step S5 is used, and the physical quantity is input in the step S1 for each of a plurality of design variables (that is, a plurality of tire models 40). The objective function is calculated. In this embodiment, the objective function of the spring constant and the objective function of the mass are calculated.

Next, in step S6, the design variable having the best objective function is selected from the plurality of design variables (that is, the plurality of tire models 40). Then, it is determined whether or not the objective function of the selected design variable satisfies a predetermined condition.

The conditions of the objective function to be satisfied are appropriately set according to the type of the tire 20 (including the category and the tire size) and the like. The conditions of the present embodiment are, for example, that the reduction rate of the mass of the tire model 40 is 10% or more, the objective function of the vertical spring constant (vertical spring constant error), and the objective function of the lateral spring constant (horizontal). It is defined as having a spring constant error) of 2% or less.

When it is determined in step S6 that the selected design variable satisfies the objective function (“Y” in step S6), the selected design variable is determined as the optimum solution of the design variable (step S7). ), The process S8 for designing the tire is carried out. On the other hand, in step S6, when it is determined that the selected design variable does not satisfy the objective function (“N” in step S6), step S9 for finding the optimum solution of the next design factor is carried out, and step S9 is performed. S3 to step S6 are carried out again.

Next, in step S9 for obtaining the optimum solution of the design factor, the computer 1 obtains the optimum solution of the design factor that optimizes the objective function based on the optimization algorithm under the constraint condition. In step S9 of the present embodiment, under the constraint condition, a plurality of design factors other than the best design variable are updated (generational change) so that the objective function approaches the best design variable.

In step S9, a plurality of design variables other than the best design variable are updated so that the objective function approaches the best design variable (that is, the design variable selected in step S6). In the present embodiment, design factors of other design variables (bead set width W2, radial height H1 of bead apex rubber 3d, thickness W3 of sidewall rubber 3b, and clinch rubber 3c so as to satisfy the constraint condition are satisfied. Thickness W4) is updated. Such update of design variables (generational change) can be appropriately carried out based on particle swarm optimization (PSO) with reference to the above papers and the like. The other updated design variables are stored in computer 1.

After step S9 for finding the optimum solution of the design factor, steps S3 to S6 are carried out based on the design variable having the best objective function and the updated design variable. Therefore, in the design method of the present embodiment, the optimum solution of the design factor of the raw tire model 30 that satisfies the objective function can be surely obtained.

Next, in the step S8 of designing the tire, the tire is designed based on the raw tire model 30 obtained by using the optimum solution. In step S8 of the present embodiment, the design factors of the raw tire model 30 (in this embodiment, the bead set width W2, the radial height H1 of the bead apex rubber 3d, the thickness W3 of the sidewall rubber 3b, and the clinch rubber). Based on the optimum solution of the thickness W4) of 3c, the shape of the raw tire 2 shown in FIG. 2, the shape of the tire member 11 of the raw tire 2 shown in FIG. Will be done. The shape of the raw tire 2 and the shape of the tire member 11 of the raw tire 2 are stored in the computer 1 as design data such as CAD.

As described above, in the design method of the present embodiment, the objective function is satisfied without separately designing the raw tire 2 (shown in FIG. 2) from the tire model 40 (shown in FIG. 16) as in the conventional case. It is possible to design a raw tire 2 capable of manufacturing a tire and a tire member 11 (shown in FIG. 4A) of the raw tire 2. Therefore, in the design method of the present embodiment, the tire 20 satisfying the objective function can be efficiently designed.

In this embodiment, a tire mold is designed based on the tire model 40 obtained by using the optimum solution. It is desirable that the mold design is carried out based on the tire model 40 before the heat shrinkage calculation. Thereby, the tire 20 satisfying the objective function can be manufactured more reliably.

In the present embodiment, as the shape of the tire member model 19 (tire member 11) associated with the design factor, the shape of the sidewall rubber model 16b (sidewall rubber 3b) shown in FIG. 11 and the clinch rubber model 16c (clinch rubber) are used. Although the shape of 3c) has been exemplified, it is not limited to such an embodiment. The shape of the tire member model 19 associated with the design factor may be, for example, the shape of the tread rubber model 16a (tread rubber 3a) or the shape of the sidewall rubber model 16b (that is, the sidewall rubber 3b).

The tread rubber model 16a affects the parameters related to the ground contact shape, the rolling resistance value, and the mass among the physical quantities related to the tire performance described above. Therefore, when designing a tire that satisfies the objective function of the ground contact parameter, the rolling resistance value, and the objective function of mass, it is desirable that the shape of the tread rubber model 16a (tread rubber 3a) is associated as a design factor.

The sidewall rubber model 16b affects the spring constant, cornering power, and mass among the physical quantities related to the tire performance described above. Therefore, when designing a tire that satisfies the objective function of the spring constant, the objective function of the cornering power, and the objective function of the mass, the shape of the sidewall rubber model 16b (sidewall rubber 3b) is associated as a design factor. Is desirable.

The design factor may be associated with, for example, the fiber angles δ, φ (shown in FIGS. 3, 9 and 10) of the fiber material model 18 (fiber material 4). Such angles δ and φ affect the parameters related to the ground contact shape and the cornering power among the physical quantities related to the tire performance described above. Therefore, when designing a tire that satisfies the objective function of the ground contact parameter and the objective function of the cornering power, it is desirable that the fiber angles δ and φ of the fiber material model 18 (fiber material 4) are associated as design factors.

As the constraint condition of the present embodiment, the settable range of the bead set width W2 (shown in FIG. 4B) is set, but the present invention is not limited to such a mode. The constraint condition may be the weight of the plurality of tire member models 19 (tire member 11). As a result, the optimum solution of the design factor that satisfies the objective function of the mass can be obtained at an early stage.

Next, in the manufacturing method of the present embodiment, the step S10 for molding the raw tire 2 (shown in FIG. 2) is carried out based on the raw tire model 30 (shown in FIG. 14) using the optimum solution. In the process S10, the tire member 11 of the raw tire 2 is manufactured based on the design data (CAD data) of the tire member 11 of the raw tire 2 designed in the process S8. Then, in step S10, as shown in FIGS. 4A and 4B, the tire members 11 are joined to each other based on the molding conditions of the raw tire model 30 (for example, bead set width W2 or the like). As a result, the raw tire 2 is manufactured. In step S10, it is desirable to confirm whether or not the manufactured raw tire 2 matches the shape of the raw tire 2 designed in step S8.

Next, in the manufacturing method of the present embodiment, the step S11 of vulcanizing and molding the raw tire 2 is carried out. In step S11 of the present embodiment, as shown in FIG. 5, the raw tire 2 is put into the vulcanization die 14 and the raw tire 2 is vulcanized and molded. As a result, the tire is manufactured in step S11.

As described above, in the manufacturing method of the present embodiment, the tire 20 is designed based on the raw tire model 30 obtained by using the optimum solution, so that the tire 20 satisfying the objective function can be reliably manufactured. ..

Although the 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 into various embodiments.

Tires were designed and manufactured based on the processing procedures shown in FIGS. 6 and 8 (Examples). In the design method of the embodiment, first, a step of inputting an objective function, a design factor, and a constraint condition, and a step of inputting initial values of a plurality of design variables of the raw tire model were carried out.

Next, in the design method of the embodiment, the process of setting a raw tire model based on the initial values of a plurality of design variables, the process of acquiring a tire model having the tire shape after vulcanization, and the tire performance are related. A step of acquiring the physical quantity and a step of finding the optimum solution of the design factor for optimizing the objective function based on the optimization algorithm were carried out.

Then, in the design method, a step of designing the tire based on the raw tire model obtained by using the optimum solution was carried out. Further, in the manufacturing method of the example, a tire is manufactured by carrying out a step of molding a raw tire based on a raw tire model using an optimum solution and a step of vulcanizing and molding the raw tire. Then, it was determined whether or not the manufactured tire had the same shape as the tire model acquired by the design method, and whether or not the objective function (tire performance) calculated by the design method was satisfied. The specifications of the examples are as follows.
Tire size: 225 / 30R20
Objective function:
Objective function of spring constant:
Objective function of the vertical spring constant
= ｜ Tire model vertical spring constant-Target vertical spring constant ｜ / Target vertical spring constant
Condition of objective function of vertical spring constant:
Objective function of vertical spring constant is 0.02 (2%) or less
Objective function of the lateral spring constant
= ｜ Tire model lateral spring constant-Target lateral spring constant ｜ / Target lateral spring constant
Condition of objective function of lateral spring constant:
Objective function of lateral spring constant is 0.01 (1%) or less Objective function of mass = (reference mass-mass of tire model) / Reference mass Objective function condition of mass: 0.01 (1%) or more Constraint: Settable range of bead set width W2 (150 mm to 160 mm)
Design variables:
Bead set width W2
Radial height of bead apex rubber H1
Sidewall rubber thickness W3
Clinch rubber thickness W4

FIG. 17A is a conceptual diagram showing a part of the tire model before optimization, and FIG. 17B is a conceptual diagram showing a part of the tire model after optimization. As a result of the test, the example is a design factor that satisfies the objective function (the objective function of the vertical spring constant is 0.5%, the objective function of the horizontal spring constant is 1%, and the objective function of the mass is 1.2%). I was able to find the optimal solution for. The optimal solution of the design factors of the examples is as follows.
Bead set width W2: Initial value + 4 mm
Radial height of bead apex rubber H1: Initial value -5 mm
Sidewall rubber thickness W3: Initial value + 1mm
Clinch rubber thickness W4: Initial value + 1mm

In the embodiment, the error (mass difference) between the tire designed and manufactured based on the optimum solution and the tire model acquired by the design method is 100 g, and the tire section (that is, the tread portion and the sidewall portion). , And the structure was confirmed for each bead part), and it was confirmed that they had substantially the same shape. Furthermore, it was confirmed that the manufactured tires satisfy the objective function (tire performance) as in the tire model required by the design method. The design method of the example reduced the design time by 50% as compared with the conventional method of designing a raw tire before being vulcanized from the optimized tire. Therefore, the example was able to efficiently design the tire.

S3 Raw tire model setting process S4 Vulcanization simulation process S5 Physical quantity acquisition process S9 Optimal solution for design factors

Claims (11)

It is a method for designing a tire manufactured through a process of molding a raw tire and a process of vulcanizing and molding the raw tire.
A raw tire model setting process for setting a raw tire model in which a raw tire is modeled with a finite number of elements on the computer, and a raw tire model setting process.
A vulcanization simulation step in which the computer deforms the raw tire model based on predetermined vulcanization conditions to acquire a tire model having a tire shape after vulcanization.
A process in which the computer calculates the deformation of the tire model based on predetermined test conditions and obtains a physical quantity related to the predetermined tire performance from the calculation.
The computer optimizes the objective function based on an optimization algorithm under predetermined constraints, with the physical quantity as an objective function and a predetermined design factor of the raw tire model as a design variable. And the process of finding the optimum solution of the design factor
Including a step of designing a tire based on the raw tire model obtained by using the optimum solution.
How to design a tire. The tire according to claim 1, wherein the raw tire model is set by joining a plurality of tire member models to each other, and the design factor is associated with at least one shape of the plurality of tire member models. Design method. The tire design method according to claim 2, wherein at least one of the plurality of tire member models is a tread rubber model that models a tread rubber. The tire design method according to claim 2 or 3, wherein at least one of the plurality of tire member models is a sidewall rubber model in which the sidewall rubber is modeled. The raw tire model is set by joining a plurality of tire member models to each other.
The plurality of tire member models include a fiber material model that models a fiber material.
The tire design method according to any one of claims 1 to 4, wherein the design factor is associated with the fiber angle of the fiber material model. The tire design method according to claim 5, wherein the fiber material model includes a carcass model that models a carcass.
The tire design method according to claim 5 or 6, wherein the fiber material model includes a belt model that models a belt.
The tire design method according to claim 2, wherein the constraint conditions include the weights of the plurality of tire member models. The raw tire model setting step includes a step of defining the plurality of tire member models in the computer and a step of defining the plurality of tire member models in the computer.
The method for designing a tire according to any one of claims 2 to 8, further comprising a step of joining the plurality of tire member models to each other to define the raw tire model. The method for designing a tire according to any one of claims 1 to 9, wherein the physical quantity includes at least one of a spring constant of the tire model, a parameter relating to a ground contact shape, a rolling resistance value, a cornering power, and a mass. A step of molding a raw tire based on the raw tire model using the optimum solution obtained by using the method according to any one of claims 1 to 10.
A method for manufacturing a tire, which comprises a step of vulcanizing and molding the raw tire.

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