JP5526599B2 - Tread model creation method and computer program therefor, tire model creation method and computer program therefor - Google Patents

Description

  The present invention relates to modeling a tread of a tire, in particular a cap tread, that can be analyzed by a computer, and creating a computer modelable tire model having a modeled tread.

  Conventional tires have been developed through repeated trials and tests, which has the problem of poor development efficiency. In order to solve this problem, a method that can predict the physical properties of a tire, that is, the performance of the tire without producing a prototype by numerical analysis using a computer has been proposed and put into practical use in recent years. ing. When the performance of a tire is predicted by numerical analysis using a computer, it is necessary to make an analysis model that can be analyzed by the computer.

  As a method for creating an analysis model of a tire, for example, in Patent Document 1, a two-dimensional model is created by dividing two-dimensional CAD data of an object into a plurality of elements including at least one of a quadrilateral element and a triangular element, It is disclosed that a three-dimensional model of an object composed of at least one of a pentahedral element and a hexahedral element is created by sweeping on an axis intersecting with the two-dimensional model.

JP-A-2001-282873 [0007]

  By the way, since the technique disclosed in Patent Document 1 creates a three-dimensional model by sweeping a two-dimensional model, it is possible to create a groove having a simple shape in which the groove wall is a plane, but the groove wall has a three-dimensional shape. It is difficult to create a groove that is playing. The present invention has been made in view of the above, and an object of the present invention is to create an analysis model of a tire having a groove whose groove wall has a three-dimensional shape.

In order to solve the above-described problems and achieve the object, the tread model creation method according to the present invention is a tread model that is an analysis model that can be analyzed by a computer, in which the cap tread of a tire in which a groove is formed. The computer divides the two-dimensional shape of the cap tread including the planar shape of the groove as viewed from the tread surface side of the tire into a finite number of elements composed of a plurality of nodes, whereby two pieces of the cap tread are obtained. A procedure for creating a dimensional model, and a computer expands the two-dimensional model in the thickness direction of the cap tread, and a plurality of elements configured by a plurality of nodes are arranged in the thickness direction. A step of creating a three-dimensional model of the cap tread and a groove of a groove model formed by a computer from the planar shape of the groove A tread model is created by moving a predetermined node included in the groove wall in a direction intersecting the surface of the groove wall, and the predetermined node included in the groove wall is moved to the surface of the groove wall. In the procedure for moving in the direction intersecting with the groove, the nodes other than the nodes included in the groove wall, the predetermined nodes existing inside the three-dimensional model are also moved, and the elements including the nodes to be moved are moved. The node of the element is moved and the moving distance of the nodes to be moved is such that the angle formed by a plurality of straight lines composed of the node to be moved and at least two nodes adjacent to the node is 90 degrees Is reduced as it goes into the interior of the three-dimensional model .

  As a desirable aspect of the present invention, in the tread model creation method, it is preferable that at least three layers of elements are arranged in the groove model in the thickness direction.

  As a desirable aspect of the present invention, in the tread model creation method, a partial tread model corresponding to one pitch of a tread pattern in the tire circumferential direction is created by the tread model creation method, and the partial tread model is arranged in the tire circumferential direction. It is preferable to create a tread model over the entire tire circumferential direction by arranging one turn toward the front.

  As a desirable aspect of the present invention, in the tread model creation method, it is preferable that a plurality of different tread models are created by the tread model creation method, and the plurality of different tread models are arranged in a tire circumferential direction. .

  In order to solve the above-described problems and achieve the object, a tread model creation computer program according to the present invention causes a computer to execute the tread model creation method.

In order to solve the above-described problems and achieve the object, the tire model creation method according to the present invention is configured such that when the tire is converted into an analysis model that can be analyzed by a computer , the computer is radially inward of the cap tread of the tire. against the portion to create an inner tire model which can be analyzed by the computer, also the model creation procedure for creating a tread model by tread model creation method according to any one of claims 1 to 4, computer And a procedure for arranging and coupling the tread model outside the inner tire model.

In order to solve the above-described problems and achieve the object, the tire model creation method according to the present invention is configured such that when the tire is converted into an analysis model that can be analyzed by a computer , the computer is radially inward of the cap tread of the tire. An inner tire model that can be analyzed by a computer is created for the portion of the tread model, and a partial tread model corresponding to one pitch of the tread pattern in the tire circumferential direction is obtained by the tread model creating method according to claim 1 or 2. a step of creating, and procedures computer, outside the inner tire model, together with sequences to one round towards the partial tread model in the tire circumferential direction, that couples with the inner tire model and the partial tread model, It is characterized by including.

In order to solve the above-described problems and achieve the object, the tire model creation method according to the present invention is configured such that when the tire is converted into an analysis model that can be analyzed by a computer , the computer is radially inward of the cap tread of the tire. An inner tire model that can be analyzed by a computer is created for the portion of the above , and a procedure for creating a plurality of different tread models by the tread model creating method according to claim 1 or 2 , and a computer, And disposing the plurality of different tread models on the outer side of the tire model in the tire circumferential direction and combining the inner tire model and the plurality of different tread models.

In order to solve the above-described problems and achieve the object, the tire model creation method according to the present invention is configured such that the computer forms a tread pattern based on the tire when the tire is converted into an analysis model that can be analyzed by a computer. The tire tread model without pattern is created, and the two-dimensional shape of the tire tread including the planar shape of the groove as seen from the tread side of the tire is converted into a finite number of elements composed of a plurality of nodes. A procedure for creating a two-dimensional model of the cap tread by dividing, a procedure for a computer to transfer the two-dimensional model to the tread of the tire model without pattern, and a computer for the two-dimensional model after transfer Are expanded in the thickness direction of the cap tread, and a plurality of elements composed of a plurality of nodes are formed in the thickness direction. A procedure for creating a three-dimensional model of the cap tread that is arranged in the past, and a computer displays a predetermined node included in the groove wall of the groove model formed from the planar shape of the groove as a surface of the groove wall. A tread model for the tire model without pattern by moving in a direction intersecting with the tire model, and a tread model for the tire model without pattern in a procedure other than the nodes included in the groove wall A predetermined node existing inside the three-dimensional model, and an element including the node to be moved includes a plurality of nodes including a node to be moved and at least two nodes adjacent to the node. as the angle of the straight lines is 90 degrees to move the nodes of the element, and the moving distance of the plurality of nodes to move, the Characterized in that shall become smaller with the progress in the interior of the dimensional model.

  In order to solve the above-described problems and achieve the object, a computer program for creating a tire model according to the present invention causes a computer to execute the tire model creating method.

  The present invention can create an analysis model of a tire having a groove whose groove wall has a three-dimensional shape.

FIG. 1 is a cross-sectional view showing a meridional section passing through a rotation axis of a tire. FIG. 2 is a plan view in which a tread pattern of a tire is developed two-dimensionally. FIG. 3A is a diagram illustrating an example of a narrow groove formed in a tire block. FIG. 3-2 is a diagram illustrating an example of a narrow groove formed in a tire block. FIG. 4 is an explanatory diagram showing a configuration of an analysis model creation method according to the present embodiment. FIG. 5 is a flowchart showing the procedure of the tread model creation method according to the present embodiment. FIG. 6 is a plan view showing the shape of the tread surface of the block. FIG. 7 is a plan view showing a two-dimensional model of the block shown in FIG. FIG. 8 is a plan view showing a two-dimensional model of the block shown in FIG. FIG. 9 is an explanatory diagram showing an example of a method for creating a three-dimensional model from a two-dimensional model of a block. FIG. 10A is a perspective view of a three-dimensional model having grooves created from the two-dimensional model. FIG. 10-2 is a perspective view of a three-dimensional model having grooves created from the two-dimensional model. FIG. 11A is a diagram for explaining the movement of the node of the groove wall. FIG. 11B is a diagram for explaining the movement of the node of the groove wall. FIG. 12A is a perspective view of the three-dimensional model. 12-2 is a cross-sectional view taken along line BB in FIG. 12-1. FIG. 13A is a perspective view illustrating an example of a hexahedral element. FIG. 13B is a diagram of a state in which the nodes constituting the hexahedral element shown in FIG. FIG. 14 is a perspective view showing a block model including a three-dimensional sipe model. FIG. 15A is an explanatory diagram of a tread model creation method according to a first modification of the present embodiment. FIG. 15-2 is an explanatory diagram of a tread model creation method according to a first modification of the present embodiment. FIG. 16 is a plan view showing a partial tread model. FIG. 17 is an explanatory diagram of a tread model creation method according to a second modification of the present embodiment. FIG. 18 is an explanatory diagram of a tread model creation method according to a second modification of the present embodiment. FIG. 19 is a flowchart showing the procedure of the tire model creation method according to the present embodiment. FIG. 20 is an explanatory diagram of a tire model creation method according to the present embodiment. FIG. 21 is an explanatory diagram of a tire model creation method according to the present embodiment. FIG. 22 is a flowchart showing a procedure of a modification of the tire model creation method according to the present embodiment. FIG. 23A is an explanatory diagram of a modification of the tire model creation method according to the present embodiment. FIG. 23-2 is an explanatory diagram of a modification of the tire model creation method according to the present embodiment. FIG. 23C is an explanatory diagram of a modification of the tire model creation method according to the present embodiment. FIG. 23-4 is an explanatory diagram of a modification of the tire model creation method according to the present embodiment.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the following contents. The following constituent elements include those that can be easily assumed by those skilled in the art and those that are substantially the same. The present invention can be applied to any tire having a groove, and the application target of the present invention is not limited to a pneumatic tire. In the following, for convenience of explanation, a pneumatic tire is referred to as a tire unless otherwise specified.

  FIG. 1 is a cross-sectional view showing a meridional section passing through a rotation axis of a tire. As shown in FIG. 1, a carcass 2, a belt 3, a belt cover 4, and a bead core 5 appear on the meridional section of the tire 1. The tire 1 is a composite material structure in which rubber as a base material is reinforced by a reinforcing cord such as a carcass 2, a belt 3, or a belt cover 4 as a reinforcing material. Here, a layer made of a cord material such as a metal fiber or an organic fiber, such as the carcass 2, the belt 3, and the belt cover 4, is referred to as a cord layer.

  The carcass 2 is a strength member that serves as a pressure vessel when the tire 1 is filled with air. The carcass 2 supports a load by its internal pressure and withstands a dynamic load during traveling. The belt 3 is a layer of reinforcing cords in which rubberized cords arranged between the cap tread 6 and the carcass 2 are bundled. In the case of a bias tire, it is called a breaker. In the radial tire, the belt 3 plays an important role as a shape retention and strength member.

  A belt cover 4 is disposed on the tread surface G side of the belt 3. The belt cover 4 is formed by arranging, for example, organic fiber materials in layers, and has a role as a protective layer for the belt 3 and a role as a reinforcing layer for the belt 3. The bead core 5 is a bundle of steel wires that supports the cord tension generated in the carcass 2 by internal pressure. The bead core 5 becomes a strength member of the tire 1 together with the carcass 2, the belt 3, the belt cover 4, the cap tread 6, and the under tread 9.

  The cap tread 6 is a rubber layer that is disposed on the road surface installation portion of the tire 1 and covers the outside of the carcass 2, the belt 3, and the belt cover 4. The cap tread 6 is a portion that is in direct contact with the road surface, and a main groove 7 </ b> M extending in the circumferential direction of the tire 1 is formed on the tread surface (grounding surface) G side. The side portion of the tire 1 is called a sidewall 8 and connects between the bead core 5 and the cap tread 6. Further, a shoulder portion Sh is provided between the cap tread 6 and the sidewall 8. The cap tread 6 and the inner side in the radial direction are under treads 9. The under tread 9 is a rubber layer disposed between the cap tread 6 and the belt 3.

  FIG. 2 is a plan view in which a tread pattern of a tire is developed two-dimensionally. The tread pattern is a pattern formed by dividing the cap tread 6 (see FIG. 1) by a groove (at least one of the main groove 7M and the lateral groove 7W) formed in the tire 1. In the present embodiment, the cap tread 6 is partitioned by the main groove 7M and the lateral groove 7W. A portion defined by the main groove 7M and the lateral groove 7W is referred to as a block 10B. Further, the portion partitioned by the main groove 7M is referred to as a rib 10L. Examples of the tread pattern include a pattern (rib pattern) in which the cap tread 6 is defined only by the main groove 7M, and a pattern (lag pattern) in which the cap tread 6 is defined only by the lateral groove 7W.

  FIGS. 3A and 3B are diagrams illustrating examples of narrow grooves formed in a tire block. In order to improve the running performance of the tire 1, a narrow groove (sipe) may be formed in the block 10B. The narrow groove may be formed in the rib 10L shown in FIG. The narrow groove is a groove formed in the tire 1 like the main groove 7M and the lateral groove 7W shown in FIG.

  The narrow groove 11 shown in FIG. 3A has a cross-sectional shape when the narrow groove 11 is cut in a plane parallel to the tread surface of the block 10B, in the thickness direction of the block 10B (a direction parallel to the radial direction of the tire 1) H. It does not change toward On the other hand, the cross-sectional shape of the narrow groove 12 shown in FIG. 3-2 when the narrow groove 12 is cut in a plane parallel to the tread surface of the block 10B is different between the opening of the narrow groove 12 and the inside of the narrow groove 12. The cross-sectional shape changes toward the thickness direction H of the block 10B. Such a narrow groove is referred to as a three-dimensional sipe for convenience. Hereinafter, the narrow groove 12 is referred to as a three-dimensional sipe 12 as necessary.

  In the present embodiment, the tire 1 including the three-dimensional sipe in the cap tread 6 is a model (analysis model) that can be analyzed by a computer. The performance of the tire 1 is evaluated by executing a simulation (simulation of deformation, rolling, etc.) using a computer using the created analysis model of the tire 1. 3D sipes are complex in shape and are difficult to model easily. In addition, for example, when using an analysis method for creating an analysis model by dividing an analysis target into finite elements, such as the Finite Element Method (FEM), a 3D sipe with a complicated shape is In addition, it is difficult to improve analysis accuracy because a tetrahedral element is modeled or a hexahedral element having a large distortion is used even when a hexahedral element is used.

Therefore, in the present embodiment, an analysis model (tread model) of a tire cap tread including a three-dimensional sipe is created using the following tread model creation method, and the tire analysis model ( Tire model). In the tread model creation method according to the present embodiment, the cap tread of the tire in which the groove is formed is a tread model that is an analysis model that can be analyzed by a computer.
(1) By extracting the two-dimensional shape of the cap tread viewed from the tread side (radially outer side) of the tire and dividing the two-dimensional shape into a finite number of elements composed of a plurality of nodes, Procedure for creating a two-dimensional model of a cap tread (2) The two-dimensional model is developed in the thickness direction of the cap tread, and a plurality of elements composed of a plurality of nodes are arranged in the thickness direction. (3) A predetermined node included in the groove wall of the groove model formed from the planar shape of the groove is formed in a direction intersecting the surface of the groove wall. It includes a procedure for creating a tread model by moving it.

  An analysis model is a model used to perform noise analysis, vibration analysis, rolling analysis, etc. on an analysis target (for example, a tire) using a numerical analysis method such as a finite element method or a finite difference method. It is an analysis model that can be analyzed with, and includes a mathematical model and a mathematical discretization model. In this embodiment, the finite element method is used as an analysis method used for rolling simulation using the created tire model. When the finite element method is used as the analysis method, the analysis target is created by dividing it into a finite number of elements composed of a plurality of nodes.

  The analysis method applicable to the assembly model creation method according to the present embodiment is not limited to the finite element method, and a boundary element method (BEM), a finite difference method (FDM), or the like is also used. it can. Further, the most appropriate analysis method can be selected according to the boundary condition or the like, or a plurality of analysis methods can be used in combination. Since the finite element method is an analysis method suitable for structural analysis, it can be suitably applied particularly to a structure such as a tire.

  The tread model is an analysis model of a tire tread, more specifically, a tire tread, and is an analysis model including at least the groove bottom of the main groove and on the tread side of the groove bottom. The tire model is an analysis model of a target tire for which performance such as steering stability and durability is evaluated. Next, an apparatus for executing the tread model creation method and the tire model creation method according to the present embodiment will be described.

  FIG. 4 is an explanatory diagram showing a configuration of an analysis model creation method according to the present embodiment. 4 is a computer, and includes a processing unit 50p and a storage unit 50m. The processing unit 50p and the storage unit 50m are connected via an input / output unit (I / O) 59. The processing unit 50p includes a model creation unit 51 and an analysis unit 52. These execute the tread model creation method and the tire model creation method according to the present embodiment. The model creation unit 51 and the analysis unit 52 are connected to an input / output unit 59 and configured to exchange data with each other.

  The processing unit 50p can be configured by a memory and a CPU (Central Processing Unit). The model creation unit 51 executes the tread model creation method and the tire model creation method according to the present embodiment, and creates a tread model including a three-dimensional sipe and a tire model having the tread model. The analysis unit 52 executes various types of analysis such as noise analysis, vibration analysis, rolling analysis, and the like using the created tire model. From these analysis results, the performance of the tire is evaluated.

  A terminal device 60 is connected to the input / output unit 59. The terminal device 60 is data necessary for executing the tread model creation method and the tire model creation method according to the present embodiment, for example, the shape and dimensions of the tire and the tread pattern, the physical property value of the material constituting the tire, and the fiber material Physical property values, boundary conditions and running conditions in the analysis, and the like are given from the input / output device 61 connected to the terminal device 60 to the processing unit 50p of the analysis model creation device 50 via the input / output unit 59. Further, the terminal device 60 receives information on the created tread model and tire model, for example, coordinates, initial strain, initial stress, and the like from the processing unit 50p and the storage unit 50m of the analysis model generating device 50, and sends them to the terminal device 60. The analysis result is displayed on the connected display device 62.

  The storage unit 50m stores a computer program including processing procedures of the tread model creation method and the tire model creation method according to the present embodiment, and data such as material properties and dimensions of the tire to be evaluated. Note that data such as material physical properties and dimensions are obtained as necessary when the analysis model creation device 50 executes the tread model creation method and the tire model creation method according to the present embodiment to create the tread model or the tire model. Used. Here, the storage unit 50m can be configured by a volatile memory such as a RAM (Random Access Memory), a nonvolatile memory, a hard disk device, or a combination thereof. The storage unit 50m may be built in the processing unit 50p or may be in another device (for example, a database server). As described above, the analysis model creation device 50 may access the processing unit 50p and the storage unit 50m from the terminal device 60 through communication.

  The computer program includes the processing procedure of the tread model creation method and the tire model creation method according to the present embodiment in combination with the computer program already recorded in the model creation unit 51, the analysis unit 52, and the like included in the processing unit 50p. It may be realized. In addition, the analysis model creation apparatus 50 may realize the functions of the model creation unit 51 and the analysis unit 52 included in the processing unit 50p using dedicated hardware instead of the computer program. Next, a tread model creation method according to the present embodiment will be described.

  FIG. 5 is a flowchart showing the procedure of the tread model creation method according to the present embodiment. FIG. 6 is a plan view showing the shape of the tread surface of the block. 7 and 8 are plan views showing a two-dimensional model of the block shown in FIG. For convenience of explanation, FIG. 8 shows a part of the two-dimensional model shown in FIG.

  In executing the tread model creation method according to the present embodiment, in step S11, the two-dimensional shape of the cap tread that constitutes the tire whose performance is to be evaluated is extracted. The two-dimensional shape of the cap tread is extracted from, for example, a plan view in which the tread pattern of the tire 1 is developed two-dimensionally as shown in FIG. The two-dimensional shape of the cap tread includes information on the position and shape of the main groove, the lateral groove, the narrow groove, the three-dimensional sipe, etc., and these pieces of information are stored in the storage unit of the analysis model creation device 50 shown in FIG. 50m is stored.

  For example, a block 10B shown in FIG. 6 is an element constituting a cap tread of a tire whose performance is to be evaluated. In step S11, the position and shape of the block 10B and the three-dimensional sipe 12 are changed from the two-dimensional shape of the block 10B. Etc. are extracted. In the following, for the sake of convenience, the method for creating a tread model according to the present embodiment will be described by focusing on the block 10B having the three-dimensional sipe 12 among the elements constituting the cap tread. These components (main grooves, lateral grooves, narrow grooves, ribs, etc.) are targeted. Further, in this example, the two-dimensional shape of the cap tread for one round of the tire is extracted, but when the same tread pattern is repeated at a predetermined pitch, the two-dimensional shape of one unit of repetition is extracted, This may be developed in the circumferential direction of the tire at a predetermined pitch.

  Next, it progresses to step S12 and the shape and position of a three-dimensional sipe are set. In this embodiment, for the groove model included in the three-dimensional model obtained by developing the two-dimensional model in the thickness direction of the cap tread, for the one corresponding to the three-dimensional sipe, the node of the groove wall is moved, Form a 3D sipe into a 3D model. For this reason, it is necessary to designate the position of the groove model to be a three-dimensional sipe and the shape of the three-dimensional sipe to be created.

  In the example illustrated in FIG. 6, the shape and position of the three-dimensional sipe 12 included in the block 10 </ b> B constituting the cap tread are set. Specifically, the model creation unit 51 of the analysis model creation device 50 shown in FIG. 4 extracts the shape and position of the 3D sipe from the 2D shape information of the cap tread stored in the storage unit 50m, and stores it. The data is temporarily stored in a predetermined area of the unit 50m.

  In step S13, the model creation unit 51 creates a two-dimensional model of the cap tread from the two-dimensional shape of the cap tread. A two-dimensional model 20 shown in FIG. 7 is a two-dimensional model of a block 10B (see FIG. 6) that is an element constituting a cap tread, and a groove portion 21 appears at a position corresponding to the three-dimensional sipe 12 in FIG. .

  In creating the two-dimensional model, for example, the model creation unit 51 receives information on the two-dimensional shape of the cap tread from the storage unit 50m (for example, information on the position and shape of the main groove, lateral groove, narrow groove, three-dimensional sipe, etc. ) To get. Then, the model creation unit 51 divides the two-dimensional shape of the cap tread (for example, the two-dimensional shape of the block 10B shown in FIG. 6) into a finite number of elements composed of a plurality of nodes from the acquired information. Create a two-dimensional model of the cap tread. FIG. 8 shows a part of the two-dimensional model 20 shown in FIG. 7. In this way, the two-dimensional model 20 has a finite number of elements (two-dimensional elements) E2 composed of a plurality of nodes N. It is divided into In addition, the groove part 21 of the two-dimensional model 20 becomes a three-dimensional sipe.

  Since the two-dimensional element E2 is an element constituting the two-dimensional model 20, for example, a quadrilateral element is used. The elements of the three-dimensional model created from the two-dimensional model 20 include solid elements such as tetrahedral solid elements, pentahedral solid elements, hexahedral solid elements, shell elements such as triangular shell elements, rectangular shell elements, surface elements, and the like. It is desirable that the element be usable by a computer. In the process of analysis, the elements thus divided are identified one by one by the model creation unit 51 using the three-dimensional coordinates in the three-dimensional model.

  In the present embodiment, a three-dimensional model created from the two-dimensional model 20 is used as a tread model. In order to improve the analysis accuracy of a tire model including the tread model, the three-dimensional model is composed of hexahedral elements. Is preferred. For this reason, it is preferable that the two-dimensional element E2 constituting the two-dimensional model 20 is a quadrilateral element. For the reasons described above, the three-dimensional model created from the two-dimensional model 20 is preferably a hexahedral solid element.

  When the two-dimensional model 20 is created, the model creation unit 51 temporarily stores information (coordinates, physical property values, etc.) of each node and each element of the two-dimensional model 20 in a predetermined area of the storage unit 50m. In step S14, the model creation unit 51 creates a cap tread three-dimensional model. The three-dimensional model is created by expanding the two-dimensional model 20 in the thickness direction of the cap tread, and a plurality of elements composed of a plurality of nodes are arranged in the thickness direction of the cap tread. Composed. Next, an example of a procedure for creating a three-dimensional model will be described.

  FIG. 9 is an explanatory diagram showing an example of a method for creating a three-dimensional model from a two-dimensional model of a block. FIGS. 10A and 10B are perspective views of a three-dimensional model having grooves created from the two-dimensional model. S1, S2, and S3 in FIG. 9 indicate the generation order of the three-dimensional model created from the two-dimensional model 20. Moreover, D1 of FIG. 9 is the state which looked at the two-dimensional model 20 shown in FIG. 8 from the arrow D1, D2 is an AA arrow view of FIG. 8, D3 is the two-dimensional shown in FIG. 2 is a plan view of a model 20. FIG.

  S1 in FIG. 9 is a state where the two-dimensional model 20 is not developed in the thickness direction of the cap tread. In the present embodiment, the two-dimensional model 20 is developed in the thickness direction of the cap tread and in the direction toward the tire rotation axis, but the deployment direction is not limited to this.

  In developing the two-dimensional model 20 in the thickness direction of the cap tread, the model creation unit 51, for example, in a direction orthogonal to the two-dimensional model 20 and at a position away from each node N of the two-dimensional model 20 by a distance Δh. A new node Nn is generated (S2). As a result, a plurality of three-dimensional elements (three-dimensional elements) E3 (L1) are generated from the node N of the two-dimensional model 20 and the newly generated node Nn. As described above, since the two-dimensional element E2 constituting the two-dimensional model 20 is a quadrilateral element, the three-dimensional element E3 is a hexahedral element.

  The model creation unit 51 is three-dimensional in the thickness direction of the cap tread as many times as the thickness of the block 10B (see FIG. 6) that is the basis of the two-dimensional model 20 is realized (dimension in the thickness direction of the cap tread). The above procedure is repeated until element E3 is generated. Thereby, a plurality of three-dimensional elements E3 are generated in the thickness direction of the cap tread. In the example shown in FIG. 9, the three-dimensional model 30 is completed by generating and arranging three-dimensional elements E3 (L1, L2, L3) (S3). Here, the dimension h of the three-dimensional model 30 in the thickness direction of the cap tread corresponds to the thickness of the block 10B from which the two-dimensional model 20 is based. In forming a three-dimensional sipe model, it is preferable that the three-dimensional model 30 has at least three layers of three-dimensional elements arranged in the thickness direction of the cap tread.

  As shown in S2 and S3 of FIG. 9, the groove portion 21 of the two-dimensional model 20 becomes deeper as the three-dimensional element E3 is generated in the thickness direction of the cap tread. When the three-dimensional element E3 is generated up to the groove bottom position, the three-dimensional element E3b is generated on the radially inner side of the tire from the groove bottom position. When the three-dimensional model 30 is created in this way, a groove model 31 having a groove wall 32 and a groove bottom 33 (a portion not hatched in D2) is formed at the position of the groove portion 21 of the two-dimensional model 20. Is done. A part of the three-dimensional element E3b becomes the groove bottom 33.

  As described above, the model creation unit 51 sequentially generates the three-dimensional elements in the thickness direction of the cap tread from the two-dimensional model 20 to develop the two-dimensional model 20 in the thickness direction, thereby generating the three-dimensional model 30. Create The model creation unit 51 temporarily stores information (coordinates, physical property values, etc.) of each node and each element of the completed three-dimensional model 30 in the storage unit 50m.

  The method for creating the three-dimensional model 30 is not limited to the above method. For example, the model creation unit 51 has a thickness (dimension in the thickness direction of the cap tread) of the 3D model 30 to be created from a direction orthogonal to the 2D model 20 and from each node N of the 2D model 20. A new node Nn is generated at a distant position to create a first three-dimensional model. Then, the model creation unit 51 may create the three-dimensional model 30 by dividing the first three-dimensional model into a plurality of three-dimensional elements in the thickness direction of the cap tread. Furthermore, the three-dimensional model 30 may be created by using a known method disclosed in Japanese Patent Application Laid-Open No. 2002-283816, which is a prior application of the applicant of the present application.

  The three-dimensional model created in step S14 is as shown in FIGS. 10-1 and 10-2. FIG. 10-2 represents elements that hide the grooves in FIG. 10-1 only by outlines so that the shape of the groove model 31 can be easily understood. When the three-dimensional model 30 including the groove model 31 is created, the process proceeds to step S15. In the groove model 31, the cross-sectional shape when the groove model 31 is cut along a plane parallel to the tread surface Gm of the three-dimensional model 30 does not change in the thickness direction H of the three-dimensional model 30. In step S15, the model creation unit 51 creates a three-dimensional sipe by moving predetermined nodes included in the groove wall of the groove model 31 included in the three-dimensional model 30. Next, this method will be described.

  FIGS. 11A and 11B are diagrams for explaining the movement of the node of the groove wall. As shown in FIG. 3-2, in the three-dimensional sipe, the cross-sectional shape when the fine groove 12 is cut in a plane parallel to the tread surface of the block 10B is different between the opening of the fine groove 12 and the inside of the fine groove 12. The cross-sectional shape changes toward the thickness direction H of the block 10B. For this reason, the node included in the groove wall of the groove model 31 included in the three-dimensional model 30 shown in FIGS. 10A and 10B is moved in a direction intersecting the surface of the groove wall. The cross-sectional shape when the groove model 31 is cut along a plane parallel to the tread Gm of the three-dimensional model 30 is different between the opening and the inside of the groove model 31, and the cross-sectional shape is the same as that of the three-dimensional model 30. It is made to change toward the thickness direction H. As a result, a tread model having a three-dimensional sipe model is created.

  As shown in FIGS. 11A and 11B, for example, the nodes N1 and N2 of the groove wall 32A of the groove model 31 are moved in the direction indicated by the arrow M1, and the node N3 is moved in the direction indicated by the arrow M2. Let Here, M1 is a direction from the groove wall 32A constituting the groove model 31 of the three-dimensional model 30 to the groove wall 32B, and M2 is a direction from the groove wall 32B to the groove wall 32A. The nodes included in the groove walls 32A and 32B to be moved are determined by the shape of the created three-dimensional sipe model. For example, the model creation unit 51 determines the node to be moved, the movement direction, and the movement distance based on the information on the shape and position of the three-dimensional sipe stored in the storage unit 50m. Then, the model creation unit 51 moves the determined node to be moved.

  In step S15, when moving the nodes included in the groove walls 32A and 32B, it is preferable to move also the nodes other than the groove walls 32A and 32B and existing in the three-dimensional model 30. Accordingly, by moving the nodes included in the groove walls 32A and 32B, it is possible to suppress distortion of the shape of the three-dimensional element including the moved nodes. Next, a method for moving a predetermined node existing inside the three-dimensional model 30 will be described.

  FIG. 12A is a perspective view of the three-dimensional model. 12-2 is a cross-sectional view taken along line BB in FIG. 12-1. FIG. 13A is a perspective view illustrating an example of a hexahedral element. FIG. 13B is a diagram of a state in which the nodes constituting the hexahedral element shown in FIG. The groove model 31 included in the three-dimensional model 30 shown in FIG. 12A has a cross-sectional shape when the groove model 31 is cut along a plane parallel to the tread Gm of the three-dimensional model 30 as described above. It does not change toward the thickness direction. FIG. 12-2 is a cross section taken along the line BB of FIG. 12-1, and the groove model 31 appears in part.

  In the example illustrated in FIG. 12B, the node Na1 included in the groove wall 32A of the groove model 31 is moved toward the groove wall 32B, and the node Na2 included in the groove wall 32A is moved away from the groove wall 32B. Further, the node Nb1 included in the groove wall 32B of the groove model 31 is moved away from the groove wall 32A, and the node Nb2 included in the groove wall 32B is moved toward the groove wall 32A. Then, it can be seen that the shapes of the three-dimensional elements E3a1, E3a2, E3b1, and E3b2 including these are distorted from a rectangular parallelepiped or a cube. If the three-dimensional elements constituting the three-dimensional model 30 are distorted, the analysis accuracy is lowered. Therefore, the three-dimensional elements are preferably as close to a rectangular parallelepiped or a cube as possible.

  For this reason, in the present embodiment, the nodes other than the nodes (nodes Na1, Na2, Nb1, and Nb2) that are included and moved in the groove walls 32A and 32B, and the predetermined nodes existing inside the three-dimensional model 30 are also included. Move. This reduces the distortion of the three-dimensional elements E3a1, E3a2, E3b1, and E3b2 that are included in the groove walls 32A and 32B and include the moving nodes Na1, Na2, Nb1, and Nb2.

  The nodes to be moved among the nodes existing in the three-dimensional model 30 are nodes included in the groove walls 32A and 32B and adjacent to the nodes Na1, Na2, Nb1, and Nb2 that move. The moving direction is the same as the moving direction of the nodes Na1, Na2, Nb1, and Nb2 that are included in the groove walls 32A and 32B and move. For example, the node that exists inside the three-dimensional model 30 and is adjacent to the node Na1 is the node Na11. The movement direction of the node Na11 is the same as the movement direction of the node Na1.

  In the present embodiment, the node Na12 adjacent to the node Na11 adjacent to the node Na1 that is included in the groove wall 32A and moves inside the three-dimensional model 30 is also moved. As a result, the movement of the node Na11 in the three-dimensional model 30 can reduce the distortion of the three-dimensional element including the node Na11, so that the degradation of the analysis accuracy can be more effectively suppressed.

  In the present embodiment, the nodes Na21 and Na22 in the three-dimensional model 30 are moved by moving the node Na2, the nodes Nb11 and Nb12 in the three-dimensional model 30 are moved by moving the node Nb1, and the nodes The nodes Nb21 and Nb22 in the three-dimensional model 30 are moved by the movement of Nb2. As a result, the distortion of the three-dimensional element due to the movement of the nodes included in the groove walls 32A and 32B can be reduced, so that a decrease in analysis accuracy can be suppressed.

  When moving a plurality of nodes existing in the three-dimensional model 30 in the direction parallel to the moving direction of the moving nodes included in the groove walls 32A and 32B as in the present embodiment, the movement of these nodes is moved. The distances are preferably all equal or proportional. In this way, the distortion of the three-dimensional element constituting the three-dimensional model 30 can be reduced more effectively. As an example in which the movement distance of the nodes is in a proportional relationship, for example, the movement distance of the nodes is decreased as the movement proceeds to the inside of the three-dimensional model. Note that the model creation unit 51 executes the above-described movement of the nodes. Then, the model creation unit 51 temporarily stores the coordinates of each node after movement in the storage unit 50m.

  In the above-described movement of the node, it is preferable that the three-dimensional element including the node to be moved has an angle formed by different planes defined by at least three nodes constituting the element to be 90 degrees. Here, the node to be moved is a node included in the groove walls 32A and 32B and moved to form a three-dimensional sipe model, or a tertiary that has to be moved along with the movement of this node. It is a node in the original model 30.

  A three-dimensional element E3 shown in FIG. 13A is a normal hexahedral element and includes nodes N1 to N8. For example, the angle formed by different planes composed of at least three nodes is 90 degrees. That is, the three-dimensional element E3 is a rectangular parallelepiped or a cube. If the shape of the three-dimensional element constituting the three-dimensional model 30 shown in FIG. 12-2 is a rectangular parallelepiped or a cube as shown in FIG. 13-1, the reduction in analysis accuracy when this three-dimensional model 30 is used is reduced. small.

On the other hand, the three-dimensional element E3a shown in FIG. 13-2 moves in a direction (directions indicated by arrows M1 and M2) away from the nodes N5 and N6 of the nodes N1 and N2 constituting the three-dimensional element E3 shown in FIG. It has been moved. In this case, as shown in FIG. 13-2, there are places where the angles formed by different planes composed of at least three nodes are not 90 degrees ( the node to be moved (for example, N1) and the node concerned). The shape of the three-dimensional element E3a is different from that of a rectangular parallelepiped or a cube, and the shape of the three-dimensional element E3a is defined by the angles θ1, θ2, and θ3 formed by a plurality of straight lines composed of at least two nodes adjacent to (N2, N5). End up. When an analysis is performed using the three-dimensional model 30 including such a three-dimensional element E3a, the analysis accuracy decreases greatly.

  Therefore, in the present embodiment, when the model creation unit 51 moves a node in the 3D model 30, the angle formed by different surfaces defined by at least three nodes constituting the 3D element including the node to be moved. The node is moved so that the angle approaches 90 degrees. As a result, it is possible to avoid that the shape of the three-dimensional element including the node to be moved differs greatly from a rectangular parallelepiped or a cube, so that it is possible to suppress a decrease in analysis accuracy.

  FIG. 14 is a perspective view showing a block model including a three-dimensional sipe model. When step S15 ends, a block model 10BM including a three-dimensional sipe model (three-dimensional sipe model) 12M is completed as shown in FIG. As described above, in the present embodiment, for the sake of convenience, the procedure of the tread model creation method according to the present embodiment is described for the blocks constituting the cap tread. Therefore, the tread model TM is completed by completing the block model 10BM. (Step S16).

  According to the tread model creation method according to the present embodiment, a tread model having a three-dimensional sipe model can be easily created using hexahedral elements. For this reason, when a rolling analysis, a deformation | transformation analysis, etc. are performed using the tire model provided with the tread model created by the tread model creation method which concerns on this embodiment, the fall of analysis accuracy can be suppressed.

[First Modification]
15A and 15B are explanatory diagrams of the tread model creation method according to the first modification of the present embodiment. FIG. 16 is a plan view showing a partial tread model. More specifically, the partial tread models TM_P1 and TM_P2 shown in FIG. 16 are block models obtained by analytically modeling the blocks constituting the cap tread. Note that the scales of the partial tread models TM_P1 and TM_P2 are the same.

  The tread model creation method according to this modification example uses the tread model creation method according to the above-described embodiment to create a partial tread model corresponding to one pitch of the tread pattern in the tire circumferential direction, and the partial tread model is a tire. It is characterized in that a tread model over the entire tire circumferential direction is created by arranging one round in the circumferential direction.

  In the tire 1 illustrated in FIG. 15A, the tread pattern TP_A is repeated at a predetermined pitch p (center angle α) in the tire circumferential direction (the direction indicated by the arrow C). Therefore, the model creation unit 51 of the analysis model creation device 50 shown in FIG. 4 creates the partial tread model TM_P (see FIG. 15-2) based on the tread pattern TP_A by the tread model creation method according to the present embodiment described above. To do. Then, as illustrated in FIG. 15B, the model creating unit 51 arranges the created partial tread models TM_P for one turn in the tire circumferential direction, and creates a tread model TM_A over the entire tire circumferential direction. In this way, a tread model for one round in the tire circumferential direction can be created easily and in a short time.

  When the pitch p at which the tread pattern TP_A is repeated differs in the tire circumferential direction, the length of the tread pattern in the tire circumferential direction is adjusted according to the pitch p. For example, as in the partial tread models TM_P1 and TM_P2 shown in FIG. 16, the length in the circumferential direction (the direction indicated by the arrow C in FIG. 16) is changed and the tires are arranged in the tire circumferential direction for one round of the tire. At this time, it is preferable not to change the size of the width t of the three-dimensional sipe model 12M. In order to realize this, for example, the distance in the tire circumferential direction of the nodes constituting the partial tread models TM_P1 and TM_P2 is changed in a portion other than the three-dimensional sipe model 12M. In this way, partial tread models having lengths corresponding to different pitches p can be easily created.

[Second Modification]
17 and 18 are explanatory diagrams of a tread model creation method according to a second modification of the present embodiment. The tread model creation method according to the present modification creates a plurality of different tread models using the tread model creation method according to the above-described embodiment, and then the plurality of different tread models in the tire circumferential direction. There is a feature in the point to arrange. Different tread models have different tread patterns, or the same tread pattern on the tread, but different three-dimensional sipes.

  First, the model creation unit 51 of the analysis model creation apparatus 50 shown in FIG. 4 creates a plurality of different tread models TM1, TM2, TE3, etc. using the tread model creation method according to the above-described embodiment. Then, as shown in FIG. 17, the model creation unit 51 arranges a plurality of different tread models TM1, TM2 and the like in the tire circumferential direction. In the example shown in FIG. 17, the tread model TM1 is arranged in the region R1, the tread model TM2 is arranged in the region R2, and the tread model TM3 is arranged in the region R3. The length of the tread model TM1 and the like in the tire circumferential direction (the direction indicated by the arrow C in FIG. 17) is made larger than the contact length LC of the tire 1. Thereby, the tread model TM1 and the like can be reliably grounded.

  The tread model TM_V illustrated in FIG. 18 is configured by disposing different tread models TM1 to TM6 over the entire tire circumferential direction. It should be noted that the tread model created in this modification does not have to be arranged with different tread models throughout the tire circumferential direction, and may be configured by arranging a plurality of different tread models in part of the tire circumferential direction. .

  Since the tread model created by the tread model creation method according to the present modified example has a plurality of different tread models arranged in the tire circumferential direction, the tire model including this tread model can perform various treads in one calculation. The model can be evaluated. This improves the efficiency of evaluation. Next, a tire model creation method according to this embodiment will be described.

[Tire model creation method]
FIG. 19 is a flowchart showing the procedure of the tire model creation method according to the present embodiment. 20 and 21 are explanatory diagrams of the tire model creation method according to the present embodiment. The tire model creation method according to the present embodiment includes a tread model created by the tread model creation method according to the above-described embodiment and its modifications, and an inner tire in which a portion radially inward of the cap tread is converted into an analysis model It is characterized in that a tire model is created by combining the model.

  The tire model creation method according to the present embodiment can be realized by the above-described analysis model creation device 50 (see FIG. 4). In executing the tire model creation method according to the present embodiment, in step S21, the model creation unit 51 included in the analysis model creation device 50 shown in FIG. 4 includes the inner tire model 1IM shown in FIG. 20 and the tread model shown in FIG. Create a TM. The tread model TM is created by the model creation unit 51 using the tread model creation method according to the present embodiment. Information (coordinates, physical property values, etc.) of each node and each element of the completed tread model TM is temporarily stored in the storage unit 50m of the analysis model creation device 50 by the model creation unit 51.

  The inner tire model 1IM is, for example, an analysis model of a portion radially inward of the cap tread 6 of the tire 1 shown in FIG. When the finite element method is used for the analysis method, the model creation unit 51 divides, for example, a portion radially inward of the cap tread 6 of the tire 1 illustrated in FIG. Thus, the inner tire model 1IM is created. The model creation unit 51 temporarily stores information (coordinates, physical property values, etc.) of each node and each element of the completed inner tire model 1IM in the storage unit 50m.

  Here, the elements of the inner tire model 1IM are elements that can be used by a computer, such as solid elements such as tetrahedral solid elements, pentahedral solid elements, hexahedral solid elements, shell elements such as triangular shell elements, quadrilateral shell elements, and surface elements. Is desirable. In the process of analysis, the elements thus divided are identified one by one by the model creation unit 51 using the three-dimensional coordinates in the three-dimensional model. In order to improve analysis accuracy such as rolling analysis using the completed tire model, it is preferable that the elements constituting the inner tire model 1IM are mainly hexahedral solid elements or pentahedral solid elements.

  When the inner tire model 1IM and the tread model TM are completed, the process proceeds to step S22. In step S22, the model creating unit 51 combines the inner tire model 1IM and the tread model TM. For example, as shown in FIG. 21, the model creation unit 51 arranges the tread model TM on the outside of the inner tire model 1IM, and couples them together.

  The combination of the inner tire model 1IM and the tread model TM means that relative displacement between the inner surface Pim of the tread model TM and the outer surface Ptm of the inner tire model 1IM does not occur. For example, the model creation unit 51 constrains the nodes on the inner surface Pim of the tread model TM and the nodes on the outer surface Ptm of the inner tire model 1IM so that relative displacement therebetween does not occur. As a result, as shown in FIG. 21, the inner tire model 1IM and the tread model TM are combined to complete an integrated tire model 1M (step S23). In addition, when the shape of the created tread model TM is annular, the tread model TM is divided in the circumferential direction, and each portion is arranged outside the inner tire model 1IM, and then the tread model TM and the inner tire model 1IM are arranged. The divided tread models TM may be combined.

  When the tire model 1M is completed, the process proceeds to step S24. In step S24, the analysis unit 52 included in the processing unit 50p of the analysis model creation device 50 uses the created tire model 1M to perform dynamic analysis or static analysis represented by rolling analysis, eigenvalue analysis, frequency response analysis, Perform heat conduction analysis. And it progresses to step S25 and the performance of the tire 1 used as the basis of the created tire model 1M is evaluated based on the analysis result. The performance of the tire 1 to be evaluated includes, for example, wear resistance, durability, handling stability, characteristics on ice, rolling resistance, NV (Noise Vibration), riding comfort, spring characteristics, hydroplaning characteristics, traction There is performance etc.

  In creating the tire model, the tread model creating method according to the first and second modified examples described above may be used. For example, when using the tread model creation method according to the first modification, the model creation unit 51 creates a partial tread model TM_P shown in FIG. In step S22, the model creation unit 51 arranges the created partial tread model TM_P for one round of the inner tire model 1IM in the tire circumferential direction on the outer side of the inner tire model 1IM. Accordingly, the tread model TM_A is disposed outside the inner tire model 1IM over the entire tire circumferential direction. In this state, the model creating unit 51 combines the inner tire model 1IM and the plurality of partial tread models TM_P. This completes the tire model. This method can create a tire model in a short time when creating a tire model of a tire in which a tread pattern is repeated at a predetermined pitch p in the tire circumferential direction.

  When the tread model creation method according to the second modification is used, the model creation unit 51 creates a plurality of different tread models in step S21. In step S22, the model creation unit 51 arranges the created different tread models on the outer side of the inner tire model 1IM by one round of the inner tire model 1IM in the tire circumferential direction. Thus, a plurality of different tread models are arranged outside the inner tire model 1IM over the entire tire circumferential direction. In this state, the model creation unit 51 combines the inner tire model 1IM and a plurality of different tread models. This completes the tire model. Since a plurality of different tread models are arranged in the tire circumferential direction in the tire model created by this method, various tread models can be evaluated by one calculation.

[Modification of tire model creation method]
FIG. 22 is a flowchart showing a procedure of a modification of the tire model creation method according to the present embodiment. FIGS. 23A to 23D are explanatory diagrams of a modification of the tire model creation method according to the present embodiment. This modification is characterized by the following points. That is, a tire model without a tread pattern is created, a two-dimensional model created based on the two-dimensional shape of the cap tread is transferred to the surface of the tire model, and the two-dimensional model is transferred from this state to the thickness direction of the cap tread. Then, a three-dimensional model of the cap tread is created by expanding toward the rotation axis of the tire. Then, by moving a predetermined node included in the groove wall of the groove model formed from the planar shape of the groove in a direction intersecting the surface of the groove wall, a tire model including a tread model having a three-dimensional sipe is obtained. create.

  The tire model creation method according to this modification can be realized by the above-described analysis model creation apparatus 50 (see FIG. 4). In executing the tire model creation method according to the present modification, in step S31, the model creation unit 51 included in the analysis model creation device 50 shown in FIG. 4 is configured so that the tire model without the tread pattern shown in FIG. Tire model) 40 and a two-dimensional model 20 shown in FIG. The tread model TM is created by the model creation unit 51 using the tread model creation method according to the present embodiment. Information (coordinates, physical property values, etc.) of each node and each element of the completed tread model TM is temporarily stored in the storage unit 50m of the analysis model creation device 50 by the model creation unit 51.

  When the finite element method is used for the analysis method, the tire model 40 without a pattern has a tread pattern not formed on the tread surface, and at least a portion where the tread pattern is formed is a finite number of elements composed of a plurality of nodes. The analysis model is not divided (element divided). For example, the tire model 40 without a pattern is an analysis model in which a portion other than the cap tread 6 of the tire 1 shown in FIG. 1 is divided into elements, and the portion of the cap tread 6 is formed without dividing elements. The model creation unit 51 creates the tire model 40 without a pattern by, for example, dividing a portion other than the cap tread 6 of the tire 1 shown in FIG. 1 with a finite number of elements composed of a plurality of nodes. The model creation unit 51 temporarily stores information (coordinates, physical property values, etc.) of each node and each element of the completed tire model 40 without a pattern in the storage unit 50m.

  Here, the elements constituting the patternless tire model 40 are solid elements such as tetrahedral solid elements, pentahedral solid elements, hexahedral solid elements, triangle shell elements, shell elements such as quadrangle shell elements, surface elements, and the like. It is desirable that the element be usable. In the process of analysis, the elements thus divided are identified one by one by the model creation unit 51 using the three-dimensional coordinates in the three-dimensional model. In order to improve analysis accuracy such as rolling analysis using the completed tire model, it is preferable that the elements constituting the patternless tire model 40 are mainly hexahedral solid elements or pentahedral solid elements.

  When the tire model 40 without pattern and the two-dimensional model 20 are completed, the process proceeds to step S32. In step S32, the model creation unit 51 transfers the two-dimensional model 20 to the tread Gm of the tire model 40 without pattern as shown in FIG. Next, it progresses to step S33, and the model preparation part 51 as shown to FIGS. 10-1 and 10-2 to the part corresponded to the cap tread of the tire model 40 without a pattern as shown to FIG. 23-3. A three-dimensional model 30 is created. As described above, the three-dimensional model 30 is created by developing the two-dimensional model 20 in the thickness direction of the cap tread, that is, in the radial direction of the tire model 40 without a pattern. Since this procedure is as described above, the description is omitted.

  When the three-dimensional model 30 is created in the tire model 40 without a pattern, the process proceeds to step S34, and the model creating unit 51 moves a predetermined node included in the groove wall of the groove model 31 included in the three-dimensional model 30 to obtain the three-dimensional model. Create sipes. Since this procedure is also as described above, a description thereof will be omitted. As a result, the tread model TM (see FIG. 14) in which the three-dimensional sipe model 12M is formed is created in the portion corresponding to the cap tread of the tire model 40 without pattern, and the tire model 1M shown in FIG. 23-4 is completed. (Step S35).

  When the tire model 1M is completed, the process proceeds to step S36, and the analysis unit 52 provided in the processing unit 50p of the analysis model creation device 50 uses the created tire model 1M to perform dynamic analysis and static analysis represented by rolling analysis, Alternatively, eigenvalue analysis, frequency response analysis, heat conduction analysis, and the like are executed. And it progresses to step S37 and the performance of the tire 1 used as the basis of the created tire model 1M is evaluated based on the analysis result.

  In creating the tire model, the tread model creating method according to the first and second modified examples described above may be used. For example, in the case of using the tread model creation method according to the first modification, the model creation unit 51 is created in step S32 based on the two-dimensional shape of one unit of the tread pattern repeated in the tire circumferential direction. The model is transferred for one round at a predetermined pitch onto the tread Gm of the tire model 40 without pattern.

  When the tread model creation method according to the second modification is used, the model creation unit 51 creates a plurality of different two-dimensional models based on the two-dimensional shapes of the plurality of different tread patterns in step S32. In step S32, the model creation unit 51 transfers the created different two-dimensional models to the tread Gm of the patternless tire model 40 for one round at a predetermined pitch.

  As described above, in the present embodiment and the modified example thereof, in a tire including a groove, a tread model and a tire model having a three-dimensional groove (for example, a three-dimensional sipe) on the surface of the groove wall can be simplified using mainly hexahedron elements. Can be created. As a result, if the tire model created in this embodiment and its modification is used, a decrease in accuracy when the performance of a tire having a three-dimensional groove on the surface of the groove wall is evaluated by computer simulation is suppressed. . Although the present embodiment and the modification thereof are intended for a three-dimensional sipe, the present embodiment and the modification can be applied if the shape of the surface of the groove wall is a three-dimensional groove. For example, the contents disclosed in the present embodiment and its modifications are also effective when a protrusion, a recess, or the like is formed in a groove wall of a main groove or a lateral groove of a tire.

  As described above, the tire model creation method and the tire model creation computer program according to the present invention are useful for creating a tire or tire tread analysis model that can be analyzed by a computer.

1 tire 1M tire model 1IM inner tire model 6 cap tread 7M main groove 7W lateral groove 9 under tread 10B block 10BM block model 10L rib 11 narrow groove 12 three-dimensional sipe (thin groove)
12M 3D sipe model 20 2D model 21 Groove part 30 3D model 31 Groove model 32, 32A, 32B Groove wall 33 Groove bottom 40 Tire model 50 Analysis model creation device 50m Storage part 50p Processing part 51 Model creation part 52 Analysis part

Claims (10)

In making the tread model of the tire tread with the groove formed into an analysis model that can be analyzed by a computer,
The computer divides the two-dimensional shape of the cap tread including the planar shape of the groove as viewed from the tread surface side of the tire into a finite number of elements composed of a plurality of nodes, whereby two pieces of the cap tread are obtained. Steps to create a dimensional model,
The computer expands the two-dimensional model in the thickness direction of the cap tread, and the cap tread three-dimensionally configured by arranging a plurality of elements composed of a plurality of nodes in the thickness direction. Steps to create a model,
A procedure in which a computer creates a tread model by moving a predetermined node included in a groove wall of the groove model formed from the planar shape of the groove in a direction intersecting the surface of the groove wall;
In a procedure for moving a predetermined node included in the groove wall in a direction intersecting the surface of the groove wall,
At least two nodes other than the nodes included in the groove wall, the nodes including the nodes to be moved, which are also moved within the three-dimensional model, and adjacent to the nodes to be moved The nodes of the element are moved so that the angle between the plurality of straight lines formed by the nodes is 90 degrees, and the movement distances of the moved nodes are advanced into the three-dimensional model. Therefore , the tread model creation method characterized by having become small .   The tread model creation method according to claim 1, wherein the groove model includes at least three layers of elements arranged in the thickness direction. A partial tread model corresponding to one pitch of the tread pattern in the tire circumferential direction is created by the tread model creating method according to claim 1 or 2,
A tread model creation method for creating a tread model over the entire tire circumferential direction by arranging the partial tread models for one round in the tire circumferential direction. A plurality of different tread models are created by the tread model creating method according to claim 1 or 2,
A tread model creation method in which the plurality of different tread models are arranged in a tire circumferential direction.   A computer program for creating a tread model, which causes a computer to execute the tread model creating method according to any one of claims 1 to 4. In creating an analysis model that can be analyzed by a computer,
5. The tread model creation method according to claim 1, wherein a computer creates an inner tire model that can be analyzed by a computer for a portion radially inward of the cap tread of the tire. Model creation procedure to create a tread model by
The computer arranges and connects the tread model outside the inner tire model;
A tire model creation method comprising: In creating an analysis model that can be analyzed by a computer,
A computer creates an inner tire model that can be analyzed by a computer for a portion radially inward of the cap tread of the tire, and the tread model creating method according to claim 1 or 2 makes the tire circumferential direction Creating a partial tread model corresponding to one pitch of the tread pattern in
The computer arranges the partial tread model for one round in the tire circumferential direction outside the inner tire model, and combines the inner tire model and the partial tread model;
A tire model creation method comprising: In creating an analysis model that can be analyzed by a computer,
The computer creates an inner tire model that can be analyzed by a computer for a portion radially inward of the cap tread of the tire, and the tread model creating method according to claim 1 or 2 makes a plurality of differences. To create a tread model,
The computer arranges the plurality of different tread models on the outer side of the inner tire model in the tire circumferential direction, and combines the inner tire model and the plurality of different tread models;
A tire model creation method comprising: In creating an analysis model that can be analyzed by a computer,
A computer creates a tire model without a pattern that does not form a tread pattern based on the tire, and a two-dimensional shape of the cap tread of the tire including a planar shape of the groove as viewed from the tread side of the tire. Creating a two-dimensional model of the cap tread by dividing into a finite number of elements composed of a plurality of nodes;
A procedure for a computer to transfer the two-dimensional model to the tread of the patternless tire model;
The cap tread configured by a computer expanding the two-dimensional model after transfer in the thickness direction of the cap tread and arranging a plurality of elements including a plurality of nodes in the thickness direction. To create a 3D model of
The computer creates a tread model in the tire model without pattern by moving a predetermined node included in the groove wall of the groove model formed from the planar shape of the groove in a direction intersecting the surface of the groove wall. And the steps to
In the procedure of creating a tread model for the tire model without pattern, the nodes other than the nodes included in the groove wall, and the predetermined nodes existing inside the three-dimensional model are also moved and moved. For an element including a node, the node of the element is moved and moved so that an angle formed by a plurality of straight lines composed of the node to be moved and at least two nodes adjacent to the node is 90 degrees. A tire model creation method characterized in that a movement distance of a plurality of nodes to be reduced becomes smaller as it advances into the three-dimensional model .   A computer program for creating a tire model, which causes a computer to execute the tire model creating method according to any one of claims 6 to 9.

Images