JP6645060B2 - Method of creating a raw tire model and method of simulating a raw tire - Google Patents

Description

  The present invention relates to a method for creating a raw tire model useful for tire development and a method for simulating a raw tire.

  Patent Document 1 listed below proposes a simulation method for numerically calculating the deformation state of a green tire in a tire manufacturing process, particularly in a vulcanization process, using a computer. In Patent Literature 1 below, a raw tire model obtained by modeling a raw tire with a finite number of elements is used.

Japanese Patent No. 5297223

  The raw tire model of Patent Document 1 is set based on the actual sectional shape of the mold. On the other hand, a green tire is formed by, for example, joining a plurality of tire members to each other and deforming the tire members into a toroidal shape. Therefore, since the raw tire model of Patent Document 1 is not set based on the process of forming an actual raw tire, it differs greatly from the shape of the actual raw tire.

  The present invention has been devised in view of the above situation, and has as its main object to provide a method of creating a raw tire model and a method of simulating a raw tire that can approximate the shape of an actual raw tire. I have.

The present invention is a method for creating, using a computer, a raw tire model for numerical analysis of a raw tire including at least a first member and a second member joined to each other, the method comprising: Based on the shape of the second member before joining, modeling the first member and the second member with a finite number of elements, respectively, and inputting the first member model and the second member model to the computer; A step of defining a first raw tire model by joining at least the first member model and the second member model to each other and deforming them so as to approximate the contour of the raw tire; and A second raw tire model is modified by modifying at least the second member model so that a gap at a joint surface between the first member model and the second member model becomes zero. Characterized in that it comprises the step of defining.

  In the method for creating a raw tire model according to the present invention, prior to the correcting step, a target contour shape of the second member model in which a gap at the joint surface becomes zero is calculated from the first raw tire model. Preferably, the method further includes a step.

  In the method for creating a raw tire model according to the present invention, the correcting step includes, at least, changing the elements of the second member model so that a contour shape of the second member model matches the target contour shape. Preferably, it includes a step of redefining.

  In the method for creating a raw tire model according to the present invention, the correcting step may include setting a node of the element on the joining surface of the second member model to a node of the element on the joining surface of the first member model. It is desirable to include a step of redefining the position shared with the node.

  In the method for producing a raw tire model according to the present invention, it is preferable that the first member model is a model of a cord material, and the second member model is a model of a rubber material.

  The present invention is a simulation method for numerically calculating a vulcanization step using the second green tire model according to any one of claims 1 to 5, wherein the computer is configured to form an outer surface of the green tire. A step of inputting an outer mold model obtained by modeling an outer mold having one molding surface with a finite number of elements; and providing the computer with a finite number of inner molds having a second molding surface for molding the inner surface of the green tire. Inputting the inner mold model modeled by the elements of the above, and contacting the computer such that the first molding surface of the outer mold model and the second molding surface of the inner mold model become walls. Setting a boundary condition that defines the following, and the computer is configured to contact the outer surface of the second green tire model with the first molding surface and the inner surface of the second green tire model with the second molding surface. , The second Characterized in that it comprises a step of deforming the tire model.

  In the method for simulating deformation of a raw tire according to the present invention, the inner model is defined so as to be inflatable and deformable, and the step of deforming the second raw tire model is a step of gradually expanding the inner model. It is desirable to include

In the method for producing a raw tire model according to the first invention of the present application, the first member and the second member are each modeled by a finite number of elements based on the shapes of the first member and the second member before joining. A step of inputting the member model and the second member model to a computer, wherein the computer joins at least the first member model and the second member model to each other and deforms the first member model and the second member model so as to approximate the contour of the raw tire; Defining a tire model.

  In the method for creating a raw tire model according to the first aspect of the present invention, the first raw tire model is defined based on a step of forming an actual raw tire. Therefore, the method for creating a raw tire model according to the first invention of the present application can approximate the shape of the first raw tire model to the shape of an actual raw tire.

  By the way, since the first member model and the second member model are individually modeled, in the first raw tire model, their joint surfaces may not always be completely aligned. In the method for producing a raw tire model according to the first invention of the present application, the computer corrects at least the second member model so that a gap at a joint surface between the first member model and the second member model becomes zero. Defining a second raw tire model. Thus, the force is correctly transmitted at the joint surface between the first member model and the second member model. Therefore, it is possible to prevent one of the element of the first member model or the element of the second member model from penetrating into the other of the element of the first member model or the element of the second member model due to the deformation of the second raw tire model. It is possible to perform stable deformation calculation.

  The method for simulating deformation of a green tire according to the second invention of the present application is characterized in that the outer surface of the second green tire model of the first invention of the present invention is the first molding surface of the outer die model, and the inner surface of the second green tire model is the inner die. Deforming the second green tire model so as to contact the second molding surfaces of the model. The green tire deformation simulation method according to the second aspect of the present invention can calculate a second green tire model that reproduces the shape of the green tire in the vulcanization step.

  In addition, the second raw tire model is modified so that the gap at the joint surface between the first member model and the second member model becomes zero. Therefore, in the method for simulating the deformation of a raw tire according to the second aspect of the present invention, since the force is transmitted correctly at the joint surface between the first member model and the second member model, stable deformation calculation can be performed.

FIG. 2 is a perspective view illustrating an example of a computer according to the embodiment. It is sectional drawing which shows the raw tire to be evaluated. (A), (b) is sectional drawing explaining the molding method of a green tire. It is sectional drawing explaining the vulcanization process of a green tire. It is a flowchart which shows an example of the processing procedure of the preparation method of the raw tire model of this embodiment. It is a flow chart which shows an example of a processing procedure of a member model input process of this embodiment. It is a flow chart which shows an example of the processing procedure of the 1st member model input process of this embodiment. It is sectional drawing of a casing model and a tread ring model. It is an exploded view of a casing model. It is the elements on larger scale of a tread ring model. It is a flow chart which shows an example of the processing procedure of the 2nd member model input process of this embodiment. It is a flowchart which shows an example of the processing procedure of a 1st raw tire model definition process. It is a flowchart which shows an example of the processing procedure of a casing model definition process. (A), (b) is a figure explaining the redefinition of the element G (i) when a node coincides in a joining surface. (A), (b) is a figure explaining the redefinition of the element G (i) when a node does not correspond in a joining surface. It is a flow chart which shows an example of a processing procedure of a tread ring model definition process. It is a flowchart which shows the processing procedure of the shaping process of this embodiment. It is sectional drawing which shows the casing model which swelled to the radial direction outer side. It is sectional drawing explaining the state which deformed the tread ring model to the casing model side. It is sectional drawing explaining the state which protruded the protruding part. It is an enlarged view of the bead part of the 1st raw tire model. (A) is a sectional view showing a part of the contour of the first raw tire model, and (b) is a sectional view showing the target contour shape of (a). It is a flowchart which shows an example of the processing procedure of the 2nd raw tire model definition process of this embodiment. It is sectional drawing which shows the 2nd member model which matches with a target contour shape. 5 is a flowchart illustrating an example of a processing procedure of a simulation method according to the embodiment. It is sectional drawing which shows an outer model, an inner model, and a 2nd raw tire model. It is a flow chart which shows an example of a processing procedure of a vulcanization simulation process of this embodiment. It is sectional drawing which shows the 2nd green tire model which reproduced the shape of the green tire of a vulcanization process.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The method of creating a raw tire model of the present embodiment (hereinafter, may be simply referred to as “creation method”) is to create a raw tire model for numerical analysis that models a raw tire to be evaluated using a computer. This is the method.

  FIG. 1 shows a computer 1 that executes a creation method of the present embodiment and a method of simulating a deformation of a raw tire (hereinafter, may be simply referred to as a “simulation method”). The computer 1 includes a main body 1a, a keyboard 1b, a mouse 1c, and a display device 1d. The main body 1a is provided with an arithmetic processing unit (CPU), a ROM, a working memory, a storage device such as a magnetic disk, and disk drive devices 1a1, 1a2. Note that a processing procedure (program) for executing the creation method and the simulation method of the present embodiment is stored in the storage device in advance.

  FIG. 2 is a sectional view showing the raw tire 2 to be evaluated. As shown in FIG. 2, the raw tire 2 of the present embodiment includes at least a first member 9 and a second member 10 joined to each other.

  The first member 9 of the present embodiment is a cord material 9a. The first member 9 (cord member 9a) of the present embodiment includes a carcass ply (in the present embodiment, the inner carcass ply 6A and the outer carcass ply 6B) and a belt ply (in the present embodiment, the inner belt ply 7A, And an outer belt ply 7B) and a bead core 5. The "inside" and "outside" are distinguished by the position of the tire equator C.

  The inner carcass ply 6A and the outer carcass ply 6B extend from the tread portion 2a to the bead core 5 of the bead portion 2c via the sidewall portion 2b. The inner carcass ply 6A and the outer carcass ply 6B have carcass cords (not shown) arranged at an angle of, for example, 75 to 90 degrees with respect to the tire equator C. The carcass cord is covered with a topping rubber (not shown). As the carcass cord, for example, an organic fiber cord or the like is suitably adopted.

  The inner belt ply 7A and the outer belt ply 7B are arranged outside the inner carcass ply 6A and the outer carcass ply 6B in the tire radial direction and inside the tread portion 2a. The inner belt ply 7A and the outer belt ply 7B are provided with belt cords (not shown) arranged at an angle of, for example, 10 to 40 degrees with respect to the tire circumferential direction. The belt cord is covered with a topping rubber (not shown). The inner belt ply 7A and the outer belt ply 7B are overlapped so that the belt cords cross each other. Note that, for the belt cord, for example, steel cord, aramid, rayon, or the like is suitably adopted.

  The bead core 5 is formed, for example, by spirally winding a steel bead wire a predetermined number of times, and then coating the steel wire having a substantially rectangular cross section with rubber.

  The second member 10 of the present embodiment is a rubber material 10a. The second member 10 (rubber material 10a) of the present embodiment is arranged outside the outer belt ply 7B in the tread portion 2a and outside the carcass plies 6A and 6B in the sidewall portion 2b. It includes a side wall rubber 11b and a clinch rubber 11c disposed on the bead portion 2c. The second member 10 includes a bead apex rubber 11d extending radially outward from the bead core 5, an inner liner rubber 11e disposed on the inner surface of the carcass 6, and a chafer rubber 11f disposed on the radial inner surface of the bead portion 2c. Contains.

  FIGS. 3A and 3B are cross-sectional views illustrating a method of forming the green tire 2. In the molding method of the green tire 2 of the present embodiment, first, the first joined body, the second joined body, and the third joined body are joined to a cylindrical drum (not shown), similarly to the conventional molding method. It is wound. Thus, a cylindrical casing 13 (shown by a two-dot chain line) is formed.

  The first bonded body is obtained by bonding the unvulcanized inner liner rubber 11e, the unvulcanized Chefer rubber 11f, and the carcass plies 6A and 6B shown in FIG. The second joined body is obtained by joining the uncured clinch rubber 11c and the uncured sidewall rubber 11b. The third joined body is formed by joining the bead core 5 and the unvulcanized bead apex rubber 11d.

  Next, in the method of forming the green tire 2, for example, a non-vulcanized tread rubber 4a, an inner belt ply 7A, and an outer belt ply are formed on a drum (not shown) having a larger diameter than the drum forming the casing 13. 7B are joined together and wound. Thus, a cylindrical tread ring 14 is formed.

  Next, in the method of molding the green tire 2, the casing 13 is expanded (shaped) in a toroidal shape by the bead holding portion 15 that grips the bead core 5 while reducing the axial distance between the bead cores 5 and 5. The swelling of the casing 13 is realized, for example, by directly applying the internal pressure P1 to the inner liner rubber 11e forming the inner surface of the casing 13.

  On the outer peripheral surface of the casing 13, the inner peripheral surface of the tread ring 14, which is made to stand by in advance outside in the radial direction, is attached. Then, as shown in FIG. 3B, the outer peripheral surface of the casing 13 and the inner peripheral surface of the tread ring 14 are pressed by pressing a stitching roller (not shown) against the outer peripheral surface 14o of the tread ring 14. Be adhered.

  As shown in FIG. 3B, in the casing 13 to which the internal pressure P <b> 1 is applied, the protruding portion 13 p (including the side wall rubber 11 b and the clinch rubber 11 c) protruding outside the bead core 5 in the tire axial direction is formed. It is wound up around. Thereby, the raw tire 2 shown in FIG. 2 is formed. The protruding portion 13p is wound, for example, by expanding a bladder (not shown) disposed inside the protruding portion 13p.

  FIG. 4 is a cross-sectional view illustrating a vulcanizing step of the raw tire 2. In the vulcanization step, an outer mold 16 and an inner mold 17 are used. The outer mold 16 has a first molding surface 16s for molding the outer surface of the green tire 2. The inner mold 17 has a second molding surface 17s for molding the inner surface of the green tire 2. The inner mold 17 of the present embodiment is configured as a bladder made of an elastic body, but may be a rigid core.

  In the vulcanization step, first, the raw tire 2 is put into the outer mold 16 in the same manner as in the conventional tire manufacturing method. Next, in the vulcanization step, the raw tire 2 put into the outer mold 16 is pressed against the first molding surface 16s of the outer mold 16 and heated by the inner mold 17. Thereby, the green tire 2 is vulcanized and molded, and a tire (not shown) is manufactured.

  FIG. 5 is a flowchart illustrating an example of a processing procedure of the creation method according to the present embodiment. In the creation method according to the present embodiment, first, a first member model 19 and a second member model 20, which respectively model the first member 9 and the second member 10 shown in FIG. Input step S1). In the member model input step S1, the first member model 19 and the second member model 20 are modeled based on the shapes of the first member 9 and the second member 10 before joining. FIG. 6 is a flowchart illustrating an example of a processing procedure of the member model input step S1 of the present embodiment.

  In the member model input step S1 of the present embodiment, a first member model 19 (shown in FIG. 8) in which the first member 9 (shown in FIG. 2) is modeled by a finite number of elements F (i) is input (FIG. 8). First member model input step S11). As shown in FIG. 2, the first member 9 is a cord material 9a. The cord material 9a of the present embodiment includes an inner carcass ply 6A, an outer carcass ply 6B, an inner belt ply 7A, an outer belt ply 7B, and a bead core 5. Therefore, in the first member model input step S11, the inner carcass ply 6A, the outer carcass ply 6B, the inner belt ply 7A, the outer belt ply 7B, and the bead core 5 are modeled. FIG. 7 is a flowchart illustrating an example of a processing procedure of the first member model input step S11 of the present embodiment. FIG. 8 is a cross-sectional view of the casing model and the tread ring model. FIG. 9 is an exploded view of the casing model.

  In the first member model input step S11 of the present embodiment, first, as shown in FIGS. 8 and 9, the inner carcass ply 6A (shown in FIG. 3A) is replaced with a finite number of elements F (i) ( The inside carcass ply model 21 modeled by i = 1, 2,... is input (step S111). In step S111, for example, design data (eg, CAD data) of the inner carcass ply 6A (shown in FIG. 4) wound around a drum (not shown) is input to the computer 1. The design data includes an arrangement of carcass cords (not shown) and numerical data on the contour of a topping rubber (not shown) covering the carcass cords. Then, in step S111, the inner carcass ply model 21 modeled (discrete) with a finite number of elements F (i) is set based on the design data of the inner carcass ply 6A.

  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 the present embodiment, the finite element method is adopted.

  As the element F (i), for example, a three-dimensional solid element or a beam element can be adopted. The solid element is preferably a hexahedral element with good accuracy and easy setting of the contact surface, but may be a tetrahedral element suitable for expressing a complex shape. Elements may be employed. In addition, each element F (i) has an element number, a number of the node 25, a coordinate value of the node 25, and a material property (for example, density, tensile rigidity, compressive rigidity, shear rigidity, bending rigidity, or torsional rigidity). Numerical data is defined. Such an inner carcass ply model 21 is input to the computer 1.

  Next, in the first member model input step S11 of the present embodiment, the outer carcass ply 6B (shown in FIG. 3A) is modeled with a finite number of elements F (i) (i = 1, 2,...). The converted outer carcass ply model 22 is input (step S112). In step S112, the outer carcass ply model 22 is set based on the same processing procedure as step S111 in which the inner carcass ply model 21 is input. As the element F (i), the same element as the element F (i) of the inner carcass ply model 21 can be adopted. In this element F (i), numerical data including the coordinate value of the node 25 and the material properties of the outer carcass ply 6B are defined. Such an outer carcass ply model 22 is input to the computer 1.

  FIG. 10 is a partially enlarged view of the tread ring model. Next, in the first member model input step S11 of the present embodiment, as shown in FIGS. 8 and 10, the inner belt ply 7A (shown in FIG. 3A) is replaced with a finite number of elements F (i). The inner belt ply model 23 modeled in step is input (step S113). In step S113, for example, design data (for example, CAD data) of the inner belt ply 7A wound around a drum (not shown) is input to the computer 1. The design data includes numerical data on the arrangement of the belt cords (not shown) of the inner belt ply 7A and the outline of the topping rubber (not shown) covering the belt cords. Then, in step S113, an inner belt ply model 23 modeled (discretized) with a finite number of elements F (i) is set based on the design data of the inner belt ply 7A.

  As the element F (i), the same element as the element F (i) of the inner carcass ply model 21 shown in FIG. 9 can be employed. In this element F (i), numerical data including the coordinate value of the node 25 and the material properties of the inner belt ply 7A are defined. Such an inner belt ply model 23 is input to the computer 1.

  Next, in a first member model input step S11 of the present embodiment, an outer belt ply model 24 obtained by modeling the outer belt ply 7B (shown in FIG. 3A) with a finite number of elements F (i) is input. (Step S114). In step S114, the outer belt ply model 24 is set based on the same processing procedure as in step S113 of inputting the inner belt ply model 23. As the element F (i), the same element as the element F (i) of the inner belt ply model 23 is employed. In this element F (i), numerical data including the coordinate value of the node 25 and the material characteristics of the outer belt ply 7B are defined. Such an outer belt ply model 24 is input to the computer 1.

  Next, in the first member model input step S11 of the present embodiment, as shown in FIGS. 8 and 9, the bead core 5 (shown in FIG. 3A) is modeled with a finite number of elements F (i). The converted bead core model 33 is input (step S115). In step S115, for example, design data (for example, CAD data) of the inner carcass ply 6A (shown in FIG. 4) wound around a drum (not shown) is input to the computer 1. The design data includes an arrangement of the codes (not shown) of the bead core 5 and numerical data on the contour of the topping rubber (not shown) covering the codes. Then, in step S115, based on the design data of the bead core 5, a bead core model 33 modeled (discretized) with a finite number of elements F (i) is set.

  As the element F (i), the same element as the element F (i) of the inner carcass ply model 21 can be adopted. In this element F (i), numerical data including the coordinate value of the node 25 and the material properties of the bead core 5 (shown in FIG. 3A) are defined. Such a bead core model 33 is input to the computer 1.

  As shown in FIG. 6, in the member model input step S1 of the present embodiment, a second member model 20 (shown in FIG. 8) is obtained by modeling the second member 10 (shown in FIG. 2) with a finite number of elements. Is input (second member model input step S12). As shown in FIG. 2, the second member 10 of the present embodiment is a rubber material 10a. The rubber material 10a of the present embodiment includes a tread rubber 11a, a sidewall rubber 11b, a clinch rubber 11c, a bead apex rubber 11d, an inner liner rubber 11e, and a chafer rubber 11f. Therefore, in the second member model input step S12, these rubber materials 10a (11a to 11f) are modeled. FIG. 11 is a flowchart illustrating an example of a processing procedure of the second member model input step S12 of the present embodiment.

  In the second member model input step S12 of the present embodiment, first, as shown in FIGS. 8 and 10, the tread rubber 11a (shown in FIG. The tread rubber model 27 modeled by the element G (i) (i = 1, 2,...) Is input (step S121). In step S121 of the present embodiment, for example, design data (for example, CAD data) of the unvulcanized tread ring 14 (shown in FIG. 3A) wound around a drum (not shown) is transmitted to the computer 1. Is entered. Then, based on the contour of the unvulcanized tread rubber 11a included in the design data, the model is modeled (discreteized) with a finite number of elements G (i). Thus, in step S121, a tread rubber model 27 that models the unvulcanized tread rubber 11a (shown in FIG. 3A) is set. As the numerical analysis method of the element G (i), the same method (the finite element method in the present embodiment) as the numerical analysis method of the element F (i) is adopted.

  As the element G (i), for example, a three-dimensional solid element is employed. The solid element is preferably a hexahedral element with good accuracy and easy setting of the contact surface, but may be a tetrahedral element suitable for expressing a complex shape. Elements may be employed. Each element G (i) has numerical data such as an element number, a number of the node 26, a coordinate value of the node 26, and material characteristics of the unvulcanized tread rubber 11a (shown in FIG. 3A). Is defined. Such a tread rubber model 27 is input to the computer 1.

  Next, in the second member model input step S12 of the present embodiment, as shown in FIGS. 8 and 9, the sidewall rubber 11b (shown in FIG. 3A) is replaced with a finite number of elements G (i). (I = 1, 2,...) To input the sidewall rubber model 28 (step S122). In step S122, for example, design data (for example, CAD data) of the unvulcanized casing 13 (shown in FIG. 3A) wound around a drum (not shown) is input to the computer 1. Then, based on the contour of the unvulcanized sidewall rubber 11b included in the design data, the model is modeled (discretized) with a finite number of elements G (i). Thereby, in step S122, the sidewall rubber model 28 is set.

  As the element G (i), the same element as the element G (i) of the tread rubber model 27 shown in FIG. 10 is employed. In the element G (i), numerical data including the coordinate value of the node 26 and the material characteristics of the unvulcanized sidewall rubber 11b are defined. Such a sidewall rubber model 28 is input to the computer 1.

  Next, in the second member model input step S12 of the present embodiment, a step S123 of inputting a clinch rubber model 29 which models the clinch rubber 11c (shown in FIG. 3A), and a bead apex rubber 11d (FIG. 3) The step S124 of inputting the bead apex rubber model 30 which models (shown in (a)) is sequentially performed. Further, in the second member model inputting step S12, an inner liner rubber model 31 that models the inner liner rubber 11e (shown in FIG. 3A) is input in a step S125, and the chafer rubber 11f (FIG. 3A) is input. (Step S126) of inputting the Chefer rubber model 32 which is a model of the model shown in FIG.

  Steps S123 to S126 are similar to step S122 of inputting the sidewall rubber model 28. The clinch rubber 11c, the bead apex rubber 11d, and the inner liner rubber of the design data of the unvulcanized casing 13 shown in FIG. Based on the contours of 11e and 11f, the model is modeled (discretized) by a finite number of elements G (i). Thus, in steps S123 to S126, the clinch rubber model 29, the bead apex rubber model 30, the inner liner rubber model 31, and the Chefer rubber model 32 are set, respectively.

  As the element G (i), the same element as the element G (i) of the tread rubber model 27 and the sidewall rubber model 28 shown in FIG. 10 is employed. The element G (i) includes the coordinate value of the node 26 and the material properties of the unvulcanized clinch rubber 11c, bead apex rubber 11d, inner liner rubber 11e, or Chefer rubber 11f shown in FIG. Are defined respectively. These rubber models 29 to 32 are input to the computer 1.

  Next, in the creation method of the present embodiment, the computer 1 defines a first raw tire model (first raw tire model defining step S2). In the first green tire model definition step S2, at least the first member model 19 and the second member model 20 are joined together and deformed to approximate the contour of the raw tire 2. FIG. 12 is a flowchart illustrating an example of a processing procedure of the first raw tire model definition step S2.

  In the first raw tire model definition step S2 of the present embodiment, first, a casing model 36 (shown in FIG. 8) that models the cylindrical casing 13 (shown in FIG. 3A) is set (casing model definition). Step S21). FIG. 13 is a flowchart illustrating an example of a processing procedure of the casing model definition step S21.

  In the casing model defining step S21 of the present embodiment, first, the inner carcass ply model 21, the outer carcass ply model 22, the clinch rubber model 29, the side wall rubber model 28, the bead apex rubber model 30, and the inner liner rubber shown in FIG. Boundary conditions defining contact are set so that the outer surfaces of the model 31, the Chefer rubber model 32, and the bead core model 33 become walls (step S211). These boundary conditions are input to the computer 1.

  Next, in the casing model defining step S21 of the present embodiment, a first joint model 34a in which the inner carcass ply model 21, the outer carcass ply model 22, the inner liner rubber model 31, and the Chefer rubber model 32 are joined is set. (Step S212).

  In step S212 of this embodiment, for example, based on the design data of the unvulcanized casing 13 (shown in FIG. 3A), the inner liner rubber model 31, the Chefer rubber model 32, the inner carcass ply model 21, An outer carcass ply model 22 is arranged. Then, in step S212, at each joint surface of the inner liner rubber model 31, the Chefer rubber model 32, the inner carcass ply model 21, and the outer carcass ply model 22, the node 25 of each element F (i) or each element G The element F (i) and the element G (i) are redefined so that the node 26 of (i) shares.

  FIGS. 14A and 14B are diagrams for explaining the redefinition of the element G (i) when the nodes coincide at the joint surface. As shown in FIG. 14A, for example, when the node 25 at the joint surface of the inner carcass ply model 21 and the node 26 at the joint surface of the inner liner rubber model 31 match, FIG. As shown in b), the node 25 of the inner carcass ply model 21 is defined as a new node 26 of the inner liner rubber model 31. Note that the coincidence of the nodes indicates that the coordinate values coincide in the X-axis direction, the Y-axis direction, and the Z-axis direction.

  FIGS. 15A and 15B are diagrams illustrating the redefinition of the element G (i) in the case where the nodes do not match at the joint surface. As shown in FIG. 15A, for example, when the node 25 at the joint surface of the inner carcass ply model 21 does not match the node 26 at the joint surface of the inner liner rubber model 31, FIG. The node 25 of the inner carcass ply model 21 closest to the node 26 of the inner liner rubber model 31 is defined as a new node 26 of the inner liner rubber model 31 as shown in FIG.

  Thereby, since the first joint model 34a can completely join the joint surfaces of the inner liner rubber model 31, the Chefer rubber model 32, the inner carcass ply model 21, and the outer carcass ply model 22, they can be integrally joined. The first bonded body (ie, the unvulcanized inner liner rubber 11e, the unvulcanized Chefer rubber 11f, and the carcass plies 6A, 6B) of the actual raw tire 2 shown in FIG. As in the case of (1), it is possible to prevent a gap from being formed on each joint surface.

  Next, in the casing model defining step S21 of the present embodiment, as shown in FIG. 9, a second joint model 34b in which the clinch rubber model 29 and the sidewall rubber model 28 are joined is set (step S213).

  In step S213 of the present embodiment, for example, the clinch rubber model 29 and the sidewall rubber model 28 are arranged based on the design data of the unvulcanized casing 13 (shown in FIG. 3A). Next, in step S213, the element G (i) is redefined such that the node 26 of each element G (i) is shared on the joint surface between the clinch rubber model 29 and the sidewall rubber model 28. As the procedure for redefining the element G (i), the same procedure as the procedure of step S212 (shown in FIGS. 14 and 15) is adopted. Accordingly, the second joint model 34b can completely join the clinch rubber model 29 and the side wall rubber model 28 so that the joint surfaces of the clinch rubber model 29 and the sidewall rubber model 28 are completely aligned, and thus the actual raw tire 2 shown in FIG. Like the second bonded body (that is, the unvulcanized clinch rubber 11c and the unvulcanized sidewall rubber 11b are bonded), it is possible to prevent a gap from being formed on the bonding surface.

  Next, in the casing model defining step S21 of the present embodiment, as shown in FIG. 9, a third joint model 34c in which the bead core model 33 and the bead apex rubber model 30 are joined is set (step S214).

  In step S214 of the present embodiment, for example, the bead core model 33 and the bead apex rubber model 30 are arranged based on the design data of the unvulcanized casing 13 (shown in FIG. 3A). Then, in step S214, the element G (i) is redefined such that the node 26 of each element G (i) is shared on the joint surface between the bead core model 33 and the bead apex rubber model 30. As the procedure for redefining the element G (i), the same procedure as the procedure of step S212 (shown in FIGS. 14 and 15) is adopted. Thereby, since the third joint model 34c can completely join the joint surfaces of the bead core model 33 and the bead apex rubber model 30 to be completely aligned, the third joint model 34c of the actual raw tire 2 shown in FIG. As in the case of the third joined body (that is, the bead core 5 and the unvulcanized bead apex rubber 11d joined), it is possible to prevent a gap from being formed on the joint surface.

  Next, in the casing model defining step S21 of the present embodiment, as shown in FIG. 8, the first joint model 34a and the second joint model 34b are joined (step S215). In step S215, first, the first joint model 34a and the second joint model 34b are arranged based on the design data of the unvulcanized casing 13 (shown in FIG. 3A). Then, in step S215, a boundary condition including a fixed condition is set on the joint surface 38a between the first joint model 34a and the second joint model 34b.

  The fixing condition is defined based on the actual adhesive force between the members of the raw tire 2. Further, at the joint surface 38a between the first joint model 34a and the second joint model 34b, the node 25 of each element F (i) (shown in FIG. 9) or the node 26 of each element G (i) (FIG. 9) ) Sharing is not set. Therefore, the relative movement of the first joint model 34a and the second joint model 34b is allowed, similarly to the actual first joint and the second joint of the raw tire 2 shown in FIG.

  Next, in the casing model defining step S21 of the present embodiment, the first joint model 34a and the third joint model 34c are joined (step S216). In step S216, first, the first joint model 34a and the third joint model 34c are arranged based on the design data of the unvulcanized casing 13 (shown in FIG. 3A). Then, in step S216, a boundary condition including a fixed condition is set on the joint surface 38b of the first joint model 34a and the third joint model 34c. Thereby, a casing model 36 in which the first member model 19 and the second member model 20 are joined to each other is set.

  The fixing condition is defined based on the actual adhesive force between the members of the raw tire 2. The joint surface 38b of the first joint model 34a and the third joint model 34c shares the node 25 (shown in FIG. 9) of each element F (i) or the node 26 (shown in FIG. 9) of G (i). Is not set. Therefore, the relative movement of the first joint model 34a and the third joint model 34c is allowed, similarly to the first joint body and the third joint body of the actual raw tire 2 shown in FIG. The casing model 36 is input to the computer 1.

  Next, in the first raw tire model defining step S2 of the present embodiment, a tread ring model that models the cylindrical tread ring 14 is set (tread ring model defining step S22). FIG. 16 is a flowchart illustrating an example of a processing procedure of the treadling model definition step S22.

  In the tread ring model defining step S22 of the present embodiment, first, as shown in FIG. 10, contact is made such that the outer surfaces of the inner belt ply model 23, the outer belt ply model 24, and the tread rubber model 27 become walls. Is set (step S221). These boundary conditions are input to the computer 1.

  Next, in the tread ring model definition step S22 of the present embodiment, the inner belt ply model 23, the outer belt ply model 24, and the tread rubber model 27 are joined (step S222).

  In step S222, first, the inner belt ply model 23, the outer belt ply model 24, and the tread rubber model 27 are arranged based on the design data of the unvulcanized tread ring 14 (shown in FIG. 3A). You. Then, in step S222 of the present embodiment, in the joining surface between the inner belt ply model 23 and the outer belt ply model 24 and the joining surface between the outer belt ply model 24 and the tread rubber model 27, each element F (i) The element F (i) and the element G (i) are redefined such that the node 25 of the element G and the node 26 of each element G (i) are shared. Note that as the procedure for redefining the element F (i) and the element G (i), the same procedure as the procedure of step S212 (shown in FIGS. 14 and 15) is adopted. Thereby, a tread ring model 39 in which the first member model 19 and the second member model 20 are joined to each other is set. Such a tread ring model 39 is input to the computer 1.

  In such a tread ring model 39, the joining surface between the inner belt ply model 23 and the outer belt ply model 24 and the joining surface between the outer belt ply model 24 and the tread rubber model 27 are completely aligned and joined together. Therefore, similarly to the tread ring 14 of the raw tire 2 shown in FIG. 3A, it is possible to prevent a gap from being formed on each joint surface.

  Next, as shown in FIGS. 8 and 12, in the first raw tire model definition step S2 of the present embodiment, the outer surface 36o of the casing model 36 in the tire radial direction and the inner surface of the tread ring model 39 in the tire radial direction. A boundary condition defining contact is set such that 39i is a wall (step S23). The boundary condition is to prevent the outer surface 36o of the casing model 36 and the inner surface 39i of the tread ring model 39 from slipping through each other even if they come into contact with each other. Such a boundary condition is input to the computer 1.

  Next, in the first raw tire model definition step S2 of the present embodiment, the computer 1 defines the first raw tire model 40 by bringing the outer surface 36o of the casing model 36 into contact with the inner surface 39i of the tread ring model 39. (Shaping step S24). FIG. 17 is a flowchart illustrating a processing procedure of the shaping step S24 according to the present embodiment.

  In the shaping step S24 of the present embodiment, first, as shown in FIG. 8, the tread ring model 39 is arranged outside the casing model 36 (step S241). The radial positions of the tread ring model 39 and the casing model 36 are set based on the actual tread ring 14 shown in FIG. 3A and the radial position of the casing 13 before bulging.

  Next, in the shaping step S24 of the present embodiment, the computer performs a deformation calculation for causing the casing model 36 to bulge outward in the radial direction (step S242). FIG. 18 is a cross-sectional view showing the casing model 36 bulging radially outward.

  In step S242, first, an evenly distributed load w1 is defined on the inner surface 36i of the casing model 36. The equally distributed load w1 corresponds to the pressure of the high-pressure air that swells the casing 13 shown in FIG. The nodes 25 and 26 of the elements F (i) and G (i) of the tread ring model 39 are fixed so as not to move.

  Further, in step S242, the beads 36b, 36b are moved inward in the tire axial direction such that the distance between the beads 36b, 36b of the casing model 36 in the tire axial direction is reduced. The distance in the tire axial direction between the beads 36b, 36b is set based on the distance in the tire axial direction between the beads 13b, 13b of the expanded casing 13 shown in FIG. Thereby, in step S242, it is possible to perform a deformation calculation that causes the casing model 36 to bulge radially outward. Due to the swelling of the casing model 36, the outer surface 36o of the casing model 36 can be brought into contact with the inner surface 39i of the tread ring model 39.

  The deformation calculation of the casing model 36, the tread ring model 39, and the like is performed based on the shapes and material properties of the elements F (i) and G (i) shown in FIGS. x = 0, 1,...)). Such a deformation calculation can be calculated using commercially available finite element analysis application software such as LS-DYNA manufactured by JSOL.

  Next, in the shaping step S24 of the present embodiment, after the outer surface 36o of the casing model 36 and the inner surface 39i of the tread ring model 39 come into contact with each other, the tread ring model 39 is deformed toward the casing model 36 (step S243). FIG. 19 is a cross-sectional view illustrating a state where the tread ring model is deformed toward the casing model.

  As shown in FIG. 19, in step S243, the uniformly distributed load w2 is further defined on the outer surface 39o of the tread ring model 39. The equally distributed load w2 is set based on the pressure of a stitching roller (not shown) that presses the outer peripheral surface 14o of the tread ring 14 shown in FIG. Thereby, in step S243, the deformation calculation of the tread ring model 39 can be performed such that the inner surface 39i of the tread ring model 39 is along the outer surface 36o of the casing model 36.

  Next, in the shaping step S24 of the present embodiment, a boundary condition for preventing relative movement is set on a contact surface between the outer surface 36o of the casing model 36 and the inner surface 39i of the tread ring model 39 (step S244). Such a boundary condition integrates the casing model 36 and the tread ring model 39 without considering sharing of the nodes 25 and 26 (shown in FIGS. 9 and 10) of the elements F (i) and G (i). Can be After the boundary condition is set, the uniformly distributed load w2 defined on the outer surface 39o of the tread ring model 39 is released.

  Next, in the shaping step S24 of the present embodiment, the protruding portion 36p of the casing model 36 which protrudes outward in the tire axial direction from the bead core model 33 is wound around the bead core model 33 (step S245). FIG. 20 is a cross-sectional view illustrating a state where the protruding portion 36p is wound up.

  In step S245, an evenly distributed load w3 is defined on the inner surface of the protruding portion 36p of the casing model 36. The equally distributed load w3 is set based on the pressure of the bladder 12 pressing the inner surface of the protruding portion 13p shown in FIG. Thus, in step S245, the protruding portion 36p is wound up, and the deformation calculation of the protruding portion 36p and the bead apex rubber model 30 is performed so as to be along the outer surface of the outer carcass ply model 22 or the outer surface of the tread rubber model 27. it can.

  Next, in the shaping step S24 of the present embodiment, a boundary condition for preventing relative movement is set on the contact surface of the protruding portion 36p of the casing model 36 (step S246). In step S246, the contact surface between the protruding portion 36p and the tread rubber model 27, the contact surface between the protruding portion 36p and the outer carcass ply model 22, the contact surface between the protruding portion 36p and the bead core model 33, and the protruding portion 36p and the bead A boundary condition for preventing relative movement is set on a contact surface with the apex rubber model 30. Such a boundary condition can be obtained by taking into consideration the sharing of the nodes 25 and 26 (shown in FIG. 9) of the elements F (i) and G (i), the protruding portion 36p of the casing model 36, the tread rubber model 27, The bead core model 33 and the bead apex rubber model 30 can be integrated.

  Next, in the shaping step S24 of the present embodiment, the uniformly distributed load w1 defined in the casing model 36 and the uniformly distributed load w3 defined in the protruding portion 36p of the casing model 36 are released (step S247). ). By releasing these equally distributed loads w1 and w3, in the shaping step S24, the first member model 19 and the second member model 20 are joined to each other and approximate to the contour of the raw tire 2 shown in FIG. A deformed first raw tire model 40 is defined. Such a first raw tire model 40 is input to the computer 1.

  As described above, in the production method of the present embodiment, the first raw tire model 40 is defined according to the same procedure as the step of forming the actual raw tire 2 shown in FIGS. 3 (a) and 3 (b). . Therefore, the creation method of the present embodiment can make the shape of the first raw tire model 40 approximate to the shape of the actual raw tire 2 (shown in FIG. 2). Further, in the production method of the present embodiment, since the first member model 19 and the second member model 20 (shown in FIG. 8) are individually modeled, similar to the step of forming the actual raw tire 2, The first member model 19 and the second member model 20 can be flexibly deformed. Therefore, in the creation method of the present embodiment, the shape of the first raw tire model 40 can be effectively approximated to the shape of the actual raw tire 2 (shown in FIG. 2).

  FIG. 21 is an enlarged view of the bead portion 40c of the first raw tire model 40. As shown in FIG. 21, since the first member model 19 and the second member model 20 are individually modeled, in the first raw tire model 40, the joint surfaces 43 (particularly, The joint surfaces between the first and second member models 19 and 20 of the first joint model 34a, the second joint model 34b, and the third joint model 34c may not always be completely aligned. Examples of the joining surface 43 that is not completely aligned include a joining surface 43a between the outer carcass ply model 22 and the bead apex rubber model 30, a joining surface 43b between the inner carcass ply model 21 and the clinch rubber model 29, and an inner carcass ply model 21. 43c between the bead core model 33 and the bead apex rubber model 30, the bonding surface 43e between the inner carcass ply model 21 and the sidewall rubber model 28, and the outer carcass ply model A joining surface 43f (not shown) between the tread rubber model 27 and the tread rubber model 27 is included.

  In such a joint surface 43 (for example, joint surfaces 43a to 43f), a gap 46 is formed between the first member model 19 and the second member model 20, so that the force can be transmitted correctly (uniformly). And one of the element F (i) of the first member model 19 and the element G (i) of the second member model 20 is changed to the element F (i) of the first member model 19 or the element of the second member model 20. There is a case where the calculation ends abnormally by penetrating into the other side of G (i).

  In the creation method of the present embodiment, in the second raw tire model defining step S4 described below, the gap 46 at the joint surface 43 (for example, the joint surfaces 43a to 43f) between the first member model 19 and the second member model 20 is formed. At least the second member model 20 of the first raw tire model 40 is modified to be zero.

  As described above, the first member model 19 is a model of the cord material 9a (shown in FIG. 2). The second member model 20 is a model of the rubber material 10a (shown in FIG. 2). Such a second member model 20 has a lower rigidity than the first member model 19, and is therefore easier to correct than the first member model 19. Therefore, in the present embodiment, the second member model 20 of the first raw tire model 40 is modified.

  In the creation method according to the present embodiment, as shown in FIG. 5, prior to a second raw tire model defining step S4 described below, the computer 1 transmits the first raw tire model 40 to the bonding surface 43 (for example, the bonding surface 43a). In step S3, the target contour shape of the second member model in which the gap in steps -43f) becomes zero is calculated. FIG. 22A is a cross-sectional view showing a part of the outline of the first raw tire model 40. FIG. FIG. 22B is a cross-sectional view illustrating the target contour shape of FIG.

  In step S3, first, as shown in FIG. 22A, the first member model 19 (in the present embodiment, the inner carcass ply model 21, the outer carcass ply model 22, and the inner belt ply model 23 (shown in FIG. 10) ) And the outer belt ply model 24 (shown in FIG. 10)) and the outline 20s of the second member model 20 are acquired.

  Next, as shown in FIG. 22B, the first member model 19 of the first raw tire model 40 (in the present embodiment, the inner carcass ply model 21, the outer carcass ply model 22, the inner belt ply model 23 ( The contour 20s of the second member model 20 is corrected so as to follow the contour 19s of the outer belt ply model 24 (not shown) and the outer belt ply model 24 (not shown). Thereby, it is possible to calculate the target contour shape 44 of the second member model in which the gap 46 (shown in FIG. 22A) at the joint surface 43 (for example, the joint surfaces 43a to 43f) becomes zero. The target contour shape 44 of the second member model 20 is input to the computer 1.

  Next, in the creation method of the present embodiment, a second raw tire model definition step S4 is performed. As described above, the second raw tire model defining step S4 of the present embodiment is performed by the computer 1 on the joint surface 43 (for example, the joint surfaces 43a to 43f) between the first member model 19 and the second member model 20. The second raw material model 45 is defined by modifying the second member model 20 so that the gap becomes zero. FIG. 23 is a flowchart illustrating an example of a processing procedure of the second raw tire model defining step S4 of the present embodiment.

  The second raw tire model defining step S4 redefines the element G (i) of the second member model 20 so that at least the contour shape of the second member model 20 matches the target contour shape 44 (step S41). ). In step S41 of the present embodiment, after the element G (i) of the second member model 20 shown in FIG. 21 is invalidated, the target contour shape 44 (shown in FIG. Based on this, the second member models 20 are modeled (discretized) by the elements G (i). The element G (i) is as described above. Thereby, the second member model 20 whose contour shape matches the target contour shape 44 is defined. FIG. 24 is a cross-sectional view showing the second member model 20 that matches the target contour shape 44.

  Next, in the second raw tire model defining step S4 of the present embodiment, the node 26 of the element G (i) on the joint surface 43 (for example, the joint surfaces 43a to 43f) of the second member model 20 is defined by the first member It is redefined to a position shared with the node 25 of the element F (i) on the joint surface of the model 19 (step S42).

  In step S42, as shown in FIG. 14A, the joint 26 at the joint surface 43 of the second member model 20 and the joint surface 43 (for example, joint surfaces 43a to 43f) of the first member model 19 are formed. If the node 25 matches, the node 25 of the first member model 19 is defined as a new node 26 of the second member model 20, as shown in FIG.

  On the other hand, as shown in FIG. 15A, a node 26 at the joint surface 43 (for example, joint surfaces 43 a to 43 f) of the second member model 20 and a node 25 at the joint surface 43 of the first member model 19. 15 does not match, the node 25 of the first member model 19 closest to the node 26 of the second member model 20 is replaced with the new node 26 of the second member model 20, as shown in FIG. Is defined as

  As a result, the first member model 19 maintains the deformation generated by the deformation calculation of the casing model 36, and the joining surface 43 (for example, the joining surfaces 43a to 43f) between the first member model 19 and the second member model 20. Can be aligned. Moreover, the joint 25 between the first member model 19 and the second member model 20 shares the node 25 of the element F (i) and the node 26 of the element G (i). The second member model 20 can be defined integrally. As a result, a second raw tire model 45 (shown in FIG. 24) in which the gap 46 (shown in FIG. 21) at the joint surface 43 between the first member model 19 and the second member model 20 becomes zero is defined.

  In such a second raw tire model 45, the joining surface 43 (for example, the joining surfaces 43a to 43f) between the first member model 19 and the second member model 20 can be completely aligned. Power is transmitted correctly. Therefore, due to the deformation of the second raw tire model 45, one of the element F (i) of the first member model 19 and the element G (i) of the second member model 20 is changed to the element F (i) of the first member model 19. Alternatively, it is possible to prevent the element G (i) of the second member model 20 from penetrating into the other of the elements G (i), and to perform stable deformation calculation.

  In the second raw tire model definition step S4 of the present embodiment, the second member model 20 is modified so that the gap at the joint surface 43 between the first member model 19 and the second member model 20 becomes zero. However, the present invention is not limited to such an embodiment. For example, only the first member model 19 may be modified, or both the first member model 19 and the second member model may be modified.

  If the joint surfaces 43 between the first member models 19, 19 are not completely aligned, the first raw tire model 40 is set so that the gap between the joint surfaces 43 between the first member models 19, 19 becomes zero. It is desirable that at least one of the first member models 19 (shown in FIG. 21) be modified. Examples of the joining surface 43 that is difficult to completely align include a joining surface (not shown) between the outer carcass ply model 22 and the bead core model 33 and a joining surface (not shown) between the outer carcass ply model 22 and the inner belt ply. included. The correction of the first member model 19 can be performed in the same processing procedure as the steps S41 and S42 of the second raw tire model definition step S4.

  Next, a method of simulating the deformation of the raw tire of the present embodiment using the second raw tire model 45 (hereinafter, may be simply referred to as “simulation method”) will be described. In the simulation method of the present embodiment, the vulcanizing step of the raw tire 2 shown in FIG. 4 is numerically calculated. FIG. 25 is a flowchart illustrating an example of a processing procedure of the simulation method according to the present embodiment. FIG. 26 is a cross-sectional view showing the outer model 51, the inner model 52, and the second raw tire model 45.

  In the simulation method according to the present embodiment, first, an external model 51 obtained by modeling the external model 16 shown in FIG. 4 with a finite number of elements G (i) is input to the computer 1 (step S5). The outer mold model 51 of the present embodiment is set based on, for example, design data including the contour of the first molding surface 16s of the outer mold 16 shown in FIG. Therefore, the outer model 51 has a first forming surface 51s for forming the outer surface 45o of the second green tire model 45. The outer model 51 of the present embodiment is set in a thin plate shape extending in the tire circumferential direction, but is not limited to such a mode.

  As the element G (i) (not shown), a solid element is employed as in the element G (i) of the second member model 20. The element G (i) defines, for example, coordinate values of nodes (not shown) and numerical data including material characteristics of the outer mold 16 (shown in FIG. 4). Such an external model 51 is input to the computer 1.

  Next, in the simulation method of the present embodiment, an inner model 52 obtained by modeling the inner die shown in FIG. 4 with a finite number of elements G (i) is input to the computer 1 (step S6). The inner die model 52 of the present embodiment is set based on, for example, design data including the contour of the second forming surface 17s of the inner die 17 shown in FIG. Accordingly, the inner model 52 has a second forming surface 52s for forming the inner surface of the second green tire model 45.

  As the element G (i) (not shown), a solid element is employed similarly to the outer model 51. The element G (i) defines, for example, coordinate values of nodes (not shown) and numerical data including material characteristics of the inner mold 17 (shown in FIG. 4). As described above, the inner mold 17 of the present embodiment is a bladder configured as an elastic body. Therefore, the inner model 52 is defined to be expandable and deformable. When the inner die 17 is configured as a rigid core (not shown), the inner die model 52 is defined as not expandable and deformable (rigid), like the outer die model 51. Such an internal model 52 is input to the computer 1.

  Next, in the simulation method of the present embodiment, the computer 1 causes the outer surface 45o of the second green tire model 45 to contact the first molding surface 51s and the inner surface 45i of the second green tire model 45 to contact the second molding surface 52s. Thus, the second green tire model 45 is deformed (vulcanization simulation step S7). FIG. 27 is a flowchart illustrating an example of a processing procedure of the vulcanization simulation step S7 of the present embodiment.

  In the vulcanization simulation step S7 of the present embodiment, first, as shown in FIG. 26, the outer model 51 is arranged outside the outer surface 45o of the second green tire model 45 (step S71). In step S71, the outer surface 45o of the second green tire model 45 and the first molding surface 51s (indicated by a two-dot chain line) of the outer model 51 are separated from each other.

  Next, in the vulcanization simulation step S7 of the present embodiment, the inner model 52 is arranged inside the inner surface 45i of the second green tire model 45 (step S72). In step S72, the inner surface 45i of the second green tire model 45 and the second molding surface 52s (shown by a two-dot chain line) of the inner die model 52 are separated from each other.

  Next, in the vulcanization simulation step S7 of the present embodiment, the computer 1 is brought into contact with the computer 1 such that the first molding surface 51s of the outer model 51 and the second molding surface 52s of the inner model 52 become walls. The defined boundary conditions are set (step S73). The boundary condition is to prevent the first molded surface 51s of the outer model 51 from slipping through the second green tire model 45 and the inner model 52 from slipping through the second molded surface 52s and the second green tire model 45. belongs to. Such a boundary condition is input to the computer 1.

  Next, in the vulcanization simulation step S7 of the present embodiment, the inner model 52 is gradually expanded while the outer model 51 is gradually moved to the original position (step S74). In step S74, the outer model 51, which has been arranged outside the outer surface 45o of the second raw tire model 45, is moved to the original outer mold 16 position. Accordingly, in step S74, the outer surface 45o of the second green tire model 45 can be brought into contact with the first molding surface 51s of the outer model 51. By the contact of the first molding surface 51s of the outer model 51, the distance between the bead portions 45c, 45c of the second green tire model 45 in the tire axial direction is reduced. Then, the position (coordinate value) of the outer model 51 is fixed.

  In step S74, the uniformly distributed load w4 is defined on the inner surface of the inner model 52. The uniformly distributed load w4 corresponds to the pressure of the high-pressure air that causes the inner mold 17 shown in FIG. 4 to swell. Accordingly, in step S74, the inner model 52 can be gradually expanded, so that the inner surface 45i of the second green tire model 45 can be brought into contact with the second molding surface 52s of the inner model 52.

  FIG. 28 is a cross-sectional view showing a second green tire model 45 reproducing the shape of the green tire in the vulcanization step. Due to the further expansion of the inner die model 52, the outer surface 45o of the second green tire model 45 is pressed along the first molding surface 51s of the outer die model 51. Thereby, in the vulcanization simulation step S7, it is possible to calculate the second green tire model 45 that reproduces the shape of the green tire 2 in the vulcanization step.

  The deformation calculation of the second raw tire model 45 and the inner model 52 and the movement calculation of the outer model 51 are performed based on the shape of each element F (i) and G (i), material properties, and the like. This is performed for each time (unit time Tx (x = 0, 1,...)). Such deformation calculation can be performed using the above-mentioned commercially available finite element analysis application software.

  As described above, the second raw tire model 45 is modified such that the gap at the joint surface 43 between the first member model 19 and the second member model 20 becomes zero, as shown in FIG. . Therefore, in the simulation method of the present embodiment, since the force is correctly transmitted at the joint surface 43 between the first member model 19 and the second member model 20, stable deformation calculation can be performed.

  Next, in the simulation method of the present embodiment, as shown in FIG. 25, it is determined whether the deformed state of the second raw tire model 45 (shown in FIG. 28) is good (step S8). In step S8, for example, the quality of the deformed state of the second raw tire model 45 is determined based on the shape of the first member model 19 (shown in FIG. 24) and the shape of the second member model 20 (shown in FIG. 24). Will be determined.

  In this step S8, when it is determined that the deformed state of the second raw tire model 45 is good (“Y” in step S8), based on the first raw tire model 40 or the second raw tire model 45, Thus, the raw tire 2 (shown in FIG. 2) is manufactured (step S9). On the other hand, when it is determined that the deformation state of the second raw tire model 45 is not good (“N” in step S8), the design factor of the raw tire 2 is changed (step S10), and a step of creating a raw tire model S20 (that is, steps S1 to S4) and the simulation method (that is, steps S5 to S8 shown in FIG. 5) are performed again. As described above, in the simulation method according to the present embodiment, the design factor of the raw tire 2 (shown in FIG. 2) is changed until the deformation state of the second raw tire model 45 is improved, so that a tire having excellent molding accuracy is obtained. Can be designed efficiently.

  As described above, particularly preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the illustrated embodiments, and can be implemented in various forms.

According to the processing procedure shown in FIG. 5, a first member model and a second member model obtained by modeling a first member and a second member of a raw tire are input to a computer, and the first member model and the second member model joined to each other. Was deformed so as to approximate the contour of a raw tire, and a first raw tire model was defined (Example and Comparative Example 1).

  In the embodiment, the second member model is modified according to the processing procedure shown in FIG. 23 so that the gap at the joint surface between the first member model and the second member model becomes zero, and the second green tire model is Defined. On the other hand, in Comparative Example 1, the second raw tire model was not defined as in the example. For comparison, a raw tire model in which elements were divided based on the actual cross-sectional shape of the mold was set (Comparative Example 2). Further, the raw tire shown in FIG. 2 was manufactured (experimental example).

Then, according to the processing procedure shown in FIGS. 25 and 27, a deformation simulation for deforming the second raw tire model of the example, the first raw tire model of Comparative Example 1, and the raw tire model of Comparative Example 2 is performed. Was. The common specifications are as follows.
Tire size: 275 / 30R20
Simulation software: LS-DYNA made by JSOL

  Since the second green tire model of the example and the first green tire model of Comparative Example 1 are set based on the process of forming an actual green tire, the experimental results are larger than those of the raw tire model of Comparative Example 2. It was possible to approximate the shape of the raw tire of the example.

  In the second raw tire model of the example, since the gap at the joint surface between the first member model and the second member model was corrected to zero, stable deformation calculation could be performed in the deformation simulation. On the other hand, in the first raw tire model of Comparative Example 1, penetration of an element occurred between the first member model and the second member model, and the deformation calculation ended abnormally. Therefore, the second raw tire model of the example was able to perform stable deformation calculation while approximating the shape of the actual raw tire.

S1 Step of inputting first member model and second member model S2 Step of defining first raw tire model S4 Step of defining second raw tire model

Claims (7)

A method for creating, using a computer, a raw tire model for numerical analysis of a raw tire including at least a first member and a second member joined to each other,
Based on the shapes of the first member and the second member before joining, the first member and the second member are each modeled by a finite number of elements, and the first member model and the second member model are stored in the computer. Inputting,
A step in which the computer joins at least the first member model and the second member model to each other and deforms them so as to approximate the contour of the raw tire to define a first raw tire model;
A step in which the computer corrects at least the second member model to define a second green tire model such that a gap at a joint surface between the first member model and the second member model becomes zero. How to make a raw tire model including.
  2. The raw tire model according to claim 1, further comprising a step of calculating, from the first raw tire model, a target contour shape of the second member model in which a gap at the joining surface is zero, before the correcting step. 3. How to make. 3. The raw tire according to claim 2 , wherein the correcting includes at least a step of redefining the elements of the second member model such that a contour shape of the second member model matches the target contour shape. 4. How to create a model.
  The step of modifying includes redefining a node of the element at the joint surface of the second member model to a position shared with a node of the element at the joint surface of the first member model. Item 3. The method for creating a raw tire model according to any one of Items 1 to 3.   5. The method according to claim 1, wherein the first member model is a model of a cord material, and the second member model is a model of a rubber material. 6. . A simulation method for numerically calculating a vulcanization process using the second green tire model according to any one of claims 1 to 5,
A step of inputting, to the computer, an outer mold having an outer mold having a first molding surface for molding the outer surface of the raw tire, and modeling the outer mold with a finite number of elements;
Inputting an inner mold model obtained by modeling the inner mold having a second molding surface for molding the inner surface of the raw tire to the computer with a finite number of elements,
Setting a boundary condition defining contact with the computer such that the first molding surface of the outer mold model and the second molding surface of the inner mold model are walls;
A step in which the computer deforms the second green tire model such that an outer surface of the second green tire model contacts the first molding surface and an inner surface of the second green tire model contacts the second molding surface. And a method for simulating the deformation of a raw tire. The inner model is defined to be expandable and deformable,
The raw tire deformation simulation method according to claim 6, wherein the step of deforming the second green tire model includes a step of gradually expanding the inner model.