JP5572946B2 - Tire performance prediction method and tire performance prediction computer program - Google Patents

Description

  The present invention relates to predicting tire performance by computer simulation.

  Conventionally, tires have been developed by repeatedly making prototypes with further improvements based on results obtained by using prototypes for running tests and durability tests. Such a development method has a problem that development efficiency is low because trial production and testing are repeated. In order to solve this problem, in recent years, a method has been proposed in which the physical properties of a tire can be predicted by computer simulation using numerical analysis without manufacturing a prototype.

  In recent years, various performances of tires mounted on wheels are being predicted. For example, Patent Document 1 discloses a method of performing a virtual rim assembly process in which a rim contact area of a tire finite element model is constrained and a tire axial direction distance of a bead portion of a tire finite element model is forcibly displaced to a rim width. It is disclosed. Patent Document 2 discloses a method in which the rim of the wheel model is made wider than the bead width of the tire model, and then the rim is narrowed to be fitted to the bead portion of the tire model.

Japanese Patent No. 3363442 JP 2005-082076 A

  The method disclosed in Patent Document 1 gives a forced displacement in the tire axial direction to the bead portion. However, when the rim is actually assembled, a deformation that cannot be reproduced by the forced displacement occurs in the bead portion. For this reason, the method disclosed in Patent Document 1 is fast in calculation but has low accuracy in predicting tire performance. On the other hand, since the method disclosed in Patent Document 2 combines the bead portion with the rim, the tire performance prediction accuracy is high. However, the method disclosed in Patent Document 2 has to calculate the contact between the bead portion and the rim during execution of the rolling analysis or the like, which increases the amount of calculation, and as a result, takes a lot of time for the calculation. Cost. The present invention has been made in view of the above, and in predicting the performance of a tire combined with a structural body using a computer, the calculation accuracy is reduced while reducing the time required for calculation. It aims at suppressing.

  In order to solve the above-described problems and achieve the object, a tire performance prediction method according to the present invention includes a tire and a structure combined with the tire in a plurality of minute elements composed of a plurality of nodes. A first model creation procedure for dividing and creating a first tire model and a first structure model that can be analyzed by a computer; a model combination procedure for combining the first tire model and the first structure model; An internal pressure loading procedure for applying an internal pressure to the first tire model, a restraining procedure for restraining a node of the first tire model in contact with the first structure model so as not to cause a relative displacement, and the first Contact between the structural body model and the first tire model is released, a second model creation procedure in which the first tire model after the contact is released is used as a second tire model, and the second tie Based on the model, characterized in that it comprises a, and performance prediction procedure for predicting the performance of the tire.

  In order to solve the above-described problems and achieve the object, a tire performance prediction method according to the present invention includes a tire and a structure combined with the tire in a plurality of minute elements composed of a plurality of nodes. A first model creation procedure for dividing and creating a first tire model and a first structure model that can be analyzed by a computer; a model combination procedure for combining the first tire model and the first structure model; An internal pressure loading procedure for applying an internal pressure to the first tire model, a displacement extraction procedure for extracting a displacement of a node of the first tire model in contact with the first structure model, and a combination with the first structure model A displacement applying procedure for applying the displacement as a forced displacement to the node from which the displacement is extracted of the first tire model before, and a node after the forced displacement is applied Based on a restraint procedure for restraining so as not to cause a relative displacement, a second model creating procedure for applying an internal pressure to the first tire model after restraint to form a second tire model, and the second tire model And a performance prediction procedure for predicting the performance of the tire.

  In order to solve the above-described problems and achieve the object, a tire performance prediction method according to the present invention includes a tire and two rims included in a wheel, and a plurality of microelements configured by a plurality of nodes. A first model creation procedure for dividing and creating a first tire model and a first rim model that can be analyzed by a computer; a model combination procedure for combining a bead portion of the first tire model with the first rim model; An internal pressure loading procedure for applying an internal pressure to the tire model, a restraining procedure for restraining the nodes of the first tire model in contact with the first rim model so as not to cause relative displacement, the first rim model and the first rim model A second model creation procedure in which contact with one tire model is released, and the first tire model after the contact is released is used as a second tire model; and the second tire model Based on, characterized in that it comprises a, and performance prediction procedure for predicting the performance of the tire.

  In order to solve the above-described problems and achieve the object, a tire performance prediction method according to the present invention includes a tire and two rims included in a wheel, and a plurality of microelements configured by a plurality of nodes. A first model creation procedure for dividing and creating a first tire model and a first rim model that can be analyzed by a computer; a model combination procedure for combining a bead portion of the first tire model with the first rim model; An internal pressure loading procedure for applying an internal pressure to the tire model, a displacement extracting procedure for extracting a displacement of a node of the first tire model in contact with the first rim model, and the first tire before being combined with the first rim model A displacement applying procedure for applying the displacement as a forced displacement to a node from which the displacement is extracted and a node after the forced displacement is applied are combined. Based on a restraint procedure for restraining so that displacement does not occur, a second model creation procedure for applying an internal pressure to the first tire model after restraint to form a second tire model, and the second tire model, And a performance prediction procedure for predicting the performance of the tire.

  As a preferred aspect of the present invention, in the tire performance prediction method, in the second model creation procedure, contact with the first rim model is considered for nodes other than the nodes restrained by the restraint procedure. Is desirable.

  As a preferred aspect of the present invention, in the tire performance prediction method, in the restraint procedure, a node on the rotation axis of the first tire model, the node existing on the equator plane of the first tire model. It is desirable to constrain a certain rotation axis center node so that relative displacement does not occur.

  As a preferred aspect of the present invention, in the tire performance prediction method, it is desirable that at least one of the mass of the rim and the moment of inertia of the rim is set at the center axis of the rotation axis.

  As a preferred aspect of the present invention, in the tire performance prediction method, the second tire model is a two-dimensional model, and the tire model used for predicting the tire performance is created from the second tire model. It is desirable to be a three-dimensional model.

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

  According to the present invention, in predicting the performance of a tire combined with a structure using a computer, it is possible to suppress a decrease in prediction accuracy of tire performance while reducing the time required for calculation.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description. In addition, constituent elements in the following description include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range.

(Embodiment 1)
Embodiment 1 predicts the performance of a tire in a state where it is combined with a structure (for example, a wheel rim) using a computer, and is characterized by the following points. That is, a first tire model in which an evaluation target tire is an analysis model that can be analyzed by a computer and a first structure model (for example, a rim model) that is an analysis model that can be analyzed by a computer and combined with the tire model are created. And combine the two. Then, after applying an internal pressure to the first tire model, the nodes of the first tire model that are in contact with the first structure model are constrained so that no relative displacement occurs, and then the first structure model and The contact with the first tire model is released, and the tire performance is predicted based on the second tire model, with the first tire model after the contact is released as the second tire model.

  FIG. 1 is a cross-sectional view showing a meridional section passing through a rotation axis of a tire. The meridional section of the tire 100 includes a carcass 102, a belt 103, a belt cover 104, and a bead core 105. The tire 100 is a composite material structure in which rubber as a base material is reinforced by a reinforcing cord such as a carcass 102, a belt 103, or a belt cover 104 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 102, the belt 103, and the belt cover 104, is referred to as a cord layer.

  The carcass 102 is a strength member that serves as a pressure vessel when the tire 100 is filled with air. The carcass 102 supports a load by its internal pressure and withstands a dynamic load during traveling. The belt 103 is a layer of reinforcing cords in which rubberized cords arranged between the cap tread and the carcass 102 are bundled. In the case of a bias tire, it is called a breaker. In the radial tire, the belt 103 plays an important role as a shape maintaining and strength member.

  A belt cover 104 is disposed on the ground surface side of the belt 103. The belt cover 104 is formed, for example, by arranging organic fiber materials in layers, and has a role as a protective layer for the belt 103 and a role as a reinforcing layer for the belt 103. The bead core 105 is a bundle of steel wires that supports the cord tension generated in the carcass 102 due to internal pressure. The bead core 105 becomes a strength member of the tire 100 together with the carcass 102, the belt 103, the belt cover 104, and the tread.

  A groove 107 is formed on the ground surface 109 side of the cap tread 106. This improves drainage during rainy weather. Further, a side portion of the tire 100 is called a sidewall 108 and connects between the bead core 105 and the cap tread 106. Further, the shoulder portion Sh is between the cap tread 106 and the sidewall 108. Next, an apparatus for executing the tire performance prediction method according to the present embodiment will be described.

  FIG. 2 is an explanatory diagram illustrating a configuration of the tire performance prediction apparatus according to the first embodiment. The tire performance prediction apparatus 50 shown in FIG. 2 executes the tire performance prediction method according to the present embodiment. The tire performance prediction device 50 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 tire performance prediction 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.

A terminal device 60 is connected to the input / output unit 59. The input / output unit 59 is data necessary for executing the tire performance prediction method according to the present embodiment, for example, the physical property value of rubber constituting the tire 100, the physical property value of the fiber material, or rolling analysis or deformation analysis. , Etc., are given to the tire performance prediction device 50 by the input device 61 connected to the terminal device 60. Further, the terminal device 60 receives tire performance prediction data from the tire performance prediction device 50. This prediction data is displayed on the display device 62 connected to the terminal device 60. Furthermore, various data servers 64 ₁ , 64 _2, etc. are connected to the input / output unit 59 via the network 63. In executing the tire performance prediction method according to this embodiment, the processing unit 50p is configured to be able to use various databases stored in the various data servers 64 ₁ , 64 ₂ and the like.

The storage unit 50m stores a computer program including a processing procedure of a tire performance prediction method according to the present embodiment, which will be described later, and data such as material properties acquired from various data servers 64 ₁ , 64 _{2 and the} like. . The data such as material properties are used when the performance of the tire is predicted. Here, the storage unit 50m can be configured by a volatile memory such as a RAM (Random Access Memory), a nonvolatile memory such as a flash memory, or a combination thereof. The processing unit 50p can be configured by a memory and a CPU (Central Processing Unit). The storage unit 50m may be built in the processing unit 50p or may be in another device (for example, a database server). Thus, the tire performance prediction device 50 may access the processing unit 50p and the storage unit 50m from the terminal device 60 by communication.

  The computer program can realize the processing procedure of the tire performance prediction method according to the present embodiment by combining with the computer program already recorded in the model creation unit 51 and the analysis unit 52 provided in the processing unit 50p. May be. Further, the tire performance prediction device 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 procedure for realizing the tire performance prediction method according to the present embodiment will be described.

  FIG. 3 is a flowchart illustrating a procedure of the tire performance prediction method according to the first embodiment. FIG. 4 is a perspective view showing a tire model. FIG. 5 is a perspective view showing a wheel model. 6-10 is a figure for demonstrating the performance prediction method of the tire which concerns on Embodiment 1. FIG. FIG. 11 is a schematic diagram illustrating a state in which tire performance is predicted in the tire performance prediction method according to the first embodiment. The tire performance prediction method according to the present embodiment is realized by the above-described tire performance prediction device 50 executing a computer program that causes a computer to execute the tire performance prediction method according to the present embodiment. In the following description, a wheel rim is taken as an example of a structure combined with a tire whose performance is to be evaluated, but the structure combined with a tire whose performance is to be evaluated is not limited thereto. For example, various sensors for measuring the deformation of the tire may be a structure combined with a tire whose performance is evaluated.

  In executing the tire performance prediction method according to the present embodiment, in step S101, the model creation unit 51 of the tire performance prediction device 50 shown in FIG. 2 creates a tire model of a tire to be evaluated for performance. Create a rim model of a rim that combines tires that evaluate Step S101 corresponds to a first model creation procedure. The tire model and the rim model are both models (analysis models) that can be analyzed by a computer.

  A tire model and a rim model are models used for performing rolling analysis and deformation analysis using numerical analysis methods such as a finite element method and a finite difference method, and are models that can be analyzed by a computer. Includes mathematical discretization model. In the present embodiment, a finite element method (FEM) is used as an analysis method used for a rolling simulation using the created tire model. The analysis method applicable to the tire performance prediction 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 can also be used. . 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.

For example, when the finite element method is used, as shown in FIG. 4, the tire whose performance is evaluated is divided into a finite number of minute elements 1 ₁ , 1 ₂ , 1 _{n and the} like based on the finite element method. Thereby, the tire model 1 is created. Further, as shown in FIG. 5, based on the finite element method, a wheel rim combined with a tire whose performance is to be evaluated is changed into a finite number of microelements 4A ₁ , 4A ₂ , 4A _n , 4B ₁ , 4B ₂ , 4B _n , To divide. Thereby, the rim model 4 is created. Since a pair of rims exist in a direction parallel to the rotation axis of the wheel, the rim model 4 includes a pair of rims 4A and 4B. FIG. 5 shows the rim model 4 and the entire wheel model.

  In the present embodiment, the entire wheel is analytically modeled so that the rim model 4 is included. However, the entire wheel does not necessarily need to be analytically modeled, and only the portions of the rims 4A and 4B are analytically modeled. The rim model 4 may be created. Furthermore, the rim model 4 only needs to be analytically modeled based on, for example, the finite element method or the like, at least the range covering the bead portion of the tire model 1, and the entire rim need not be analytically modeled.

  The rim model 4 can be configured as a deformed body as a whole. That is, the rim model 4 can be configured in consideration of the elastic modulus and deformation of the rims 4A and 4B throughout the rim model 4. Further, the rim model 4 may be modeled as a rigid body instead of a deformable body. Thus, it is not necessary to consider the elastic modulus of the rim model 4 and the size of the minute elements to be divided. As a result, a decrease in the time increment value under the Courant condition can be suppressed, so that an increase in calculation time can be suppressed.

  The minute elements constituting the tire model 1 and the rim model 4 are, for example, a quadrilateral element in a two-dimensional model, a solid element such as a tetrahedral solid element, a pentahedral solid element, a hexahedral solid element in a three-dimensional model, or a triangular shell element. It is desirable to use an element that can be used by a computer, such as a shell element such as a square shell element. In the process of analysis, the microelements divided in this way are identified one by one using a two-dimensional coordinate in a two-dimensional model and using a three-dimensional coordinate in a three-dimensional model.

  The model creation unit 51 stores the tire model 1 created in step S101 as the first tire model and the rim model 4 as the first rim model 4 (first structure model) in the storage unit 50m. Next, it progresses to step S102, and the model preparation part 51 reads the 1st tire model 1 and the 1st rim model 4 from the memory | storage part 50m, and combines the 1st tire model 1 and the 1st rim model 4. FIG. Step S102 corresponds to a model combination procedure. First, as shown in FIG. 6, the model creation unit 51 sets the rim widths of the rims 4A and 4B of the first rim model 4 to be wider (rim width J2) than the regular rim width J1 of the wheel.

  Here, the rim width refers to the maximum width between both rims inside the rims of the wheel. Further, the width of the bead portion refers to the maximum width at a portion where both bead portions of the tire are combined with the rim. In the tire performance prediction method according to the present embodiment, the rim width of the first rim model 4 is changed before and after the first tire model 1 is mounted on the first rim model 4, so that the rim width and bead width change during this time.

  Before combining the first tire model 1 and the first rim model 4, both rims 4A and 4B of the first rim model 4 created in step S101 are at least in the width direction of the first tire model 1 (the Y axis that is the rotation axis). Translational degree of freedom in the direction parallel to the direction of the other direction. Here, the Y axis is a rotation axis of the first tire model 1 and the first rim model 4, the X axis is an axis orthogonal to the Y axis, and the Z axis is an axis orthogonal to the Y axis and the X axis.

When combining the first tire model 1 and the first rim model 4, the model creation unit 51 matches both the rotation axis of the first rim model 4 and the rotation axis of the first tire model 1 to match both of the first rim model 4 and the first rim model 4. The rims 4A and 4B are moved in a direction parallel to the rotation axis of the first rim model 4 so that the rims 4A and 4B approach each other. As a result, as shown in FIG. 7, the rim width of the first rim model 4 is reduced from J2 to the regular rim width J1, and the bead portion 2 of the first tire model 1 is fitted to the rims 4A and 4B. The tire model 1 and the rim model 4 are combined. At this time, the width W ₂ of the bead portion of the first tire model 1 is narrowed to W ₁ (see FIGS. 6 and 7), and becomes the width of the bead portion with respect to the regular rim width J1. When the first tire model 1 and the rim model 4 are combined, the model creation unit 51 stores a model in which the first tire model 1 and the first rim model 4 are combined in the storage unit 50m.

  Next, the process proceeds to step S103. In step S103, the model creation unit 51 reads a model in which the first tire model 1 and the first rim model 4 are combined from the storage unit 50m, and applies an internal pressure to the first tire model 1. Step S103 corresponds to an internal pressure loading procedure. This is because it is necessary to apply an internal pressure to the tire when evaluating various performances of the tire. The internal pressure may be applied when the rim width of the first rim model 4 is reduced to the normal rim width J1. Thereby, the internal pressure can be applied to the first tire model 1 while combining the first tire model 1 and the first rim model 4, so that the calculation time can be shortened accordingly.

  Next, it progresses to step S104, and the model preparation part 51 reads the 1st tire model 1 and the 1st rim model 4 from the memory | storage part 50m, and the node of the 1st tire model 1 which is contacting the 1st rim model 4 is read. The first tire model 1 and the first rim model 4 in the state are constrained so as not to cause relative displacement, and the first tire model 1 and the first rim model 4 in that state are stored in the storage unit 50m. Step S104 corresponds to a restraint procedure. In the example shown in FIG. 9, the nodes N1 to N7 of the first tire model 1 are in contact with the rim 4A of the first rim model 4, and the node N0 is not in contact. Accordingly, in step S104, the nodes (rim contact nodes) N1 to N7 of the first tire model 1 that are in contact with the rim 4A of the first rim model 4 are restrained so that no relative displacement occurs. In this way, by restraining the nodes N1 to N7, for example, when the first tire model 1 is rolled, the distance between the Y axis that is the rotation axis and the nodes N1 to N7 is maintained constant. .

  In step S104, the model creation unit 51 is a node on the Y axis that is the rotation axis of the first tire model 1 and is a node that exists on the equator plane CC of the first tire model 1. The node Nyc is also constrained so that relative displacement does not occur (see FIG. 8). In this way, by constraining the rotation axis center node Nyc and the rim contact nodes N1 to N7 so as not to cause relative displacement, the contact between the first tire model 1 and the first rim model 4 is released in the next step S105. Even so, the wheel and rim are present. Accordingly, when a rolling analysis, a deformation analysis, or the like is executed, the relative positional relationship between the two is maintained. Further, at least one of the mass and the moment of inertia of at least the rim model 4 (the rim combined with the evaluation target tire) may be set at the rotation axis center node Nyc. By doing so, it is possible to execute an analysis in consideration of the mass of the rim or the moment of inertia.

  Next, it progresses to step S105, and the model preparation part 51 reads the 1st tire model 1 and the 1st rim model 4 which read the 1st rim model 4 and the 1st tire model 1 with which the predetermined node was restrained from the memory | storage part 50m. The first tire model 1 after the release is referred to as a second tire model 1S. Step S105 corresponds to a second model creation procedure. More specifically, the definition of contact between the constrained nodes N1 to N7 and the first rim model 4 is canceled. As a result, the first tire model 1 can be handled independently from the first rim model 4, and therefore, in the rolling analysis and deformation analysis in the tire performance prediction, the first tire model 1 is used alone for analysis. Executed. The model creation unit 51 stores the first tire model 1 after the contact is released in the storage unit 50m as the second tire model 1S.

  Here, in the second model creation procedure, contact with the first rim model 4 may be taken into consideration for the nodes constrained by the constraining procedure, that is, the nodes other than the rim contact nodes N1 to N7. For example, in the example shown in FIGS. 9 and 10, the node N0 corresponds to a node other than the rim contact nodes N1 to N7. The node N0 is a node existing in the vicinity of the rim 4A of the first rim model 4 and may contact the rim 4A of the first rim model 4 in the performance prediction procedure described later. For this reason, contact with the first rim model 4 is defined for nodes other than the rim contact nodes N1 to N7, particularly nodes that may contact the first rim model 4. Thereby, it is possible to more effectively suppress a decrease in prediction accuracy of tire performance.

  Next, it progresses to step S106, and the analysis part 52 with which the tire performance prediction apparatus 50 is equipped performs a rolling analysis, a deformation | transformation analysis, etc. based on the 2nd tire model 1S obtained by step S105, and predicts a tire performance. To do. Step S106 corresponds to a performance prediction procedure. The tire model used for predicting the performance of the tire is a three-dimensional analysis model. Since the second tire model 1S obtained in step S105 is a two-dimensional analysis model, the model creation unit 51 expands the second tire model 1S around the Y axis, which is the rotation axis, by 360 degrees, and thereby obtains a three-dimensional model. Create a tire model. This three-dimensional tire model is referred to as an evaluation tire model 1E (see FIG. 11). Then, for example, as shown in FIG. 11, the evaluation tire model 1E is brought into contact with a road surface model RM created in advance, and rolling analysis and deformation analysis are executed.

  In step S106, the analysis unit 52 uses the evaluation tire model 1E to perform rolling analysis under a predetermined load, speed, slip angle, camber angle, slip ratio, lateral force, longitudinal force, and other evaluation conditions. Execute tire performance simulation by, and predict tire performance. The predicted tire performance includes various performances that can be handled by dynamic simulation of the tire, such as braking performance, running performance on a wet road surface, cornering performance, and the like. In the present embodiment, the analysis unit 52 repeatedly executes tire performance simulations by rolling analysis or the like until the number of combinations (1 or more) of predetermined loads and boundary conditions is reached, acquires physical quantities, and stores them. Stored in the unit 50m. And the performance of a tire is evaluated using the acquired physical quantity.

  Here, in the tire performance simulation executed in step S106, the first rim model 4 is not used, and the evaluation tire model 1E created from the second tire model 1S is used alone. This eliminates the need to consider the contact between the tire model and the rim model in the analysis in the tire performance simulation, thereby reducing the time required for the calculation. In the present embodiment, since the nodes of the tire model that have been in contact with the rim model are constrained so as not to cause relative displacement, the accuracy (shape and shape) of the bead portion of the evaluation tire model 1E used for tire performance simulation is limited. (Accuracy of dimensions, etc.) is ensured, and a decrease in the accuracy of analysis can be suppressed. As a result, in the tire performance prediction method according to the present embodiment, it is possible to suppress a decrease in the prediction accuracy of the tire performance while reducing the time required for the calculation. In particular, when evaluating the performance of a plurality of tires, the time required for calculation can be greatly shortened, so that the efficiency of tire research and development is improved.

(Embodiment 2)
The second embodiment is the same as the first embodiment, but after the internal pressure loading procedure, a displacement extraction procedure for extracting the displacement of the node of the first tire model that is in contact with the first structure model (first rim model); The difference is that a displacement applying procedure for applying the extracted displacement as a forced displacement to the node where the displacement is extracted of the first tire model before being combined with the first structure model is different. The restraint procedure is different in that the node after applying the forced displacement is restrained so that relative displacement does not occur. In the second model creation procedure, internal pressure is applied to the first tire model after restraint. The second tire model is different. Other configurations are the same as those of the first embodiment.

  FIG. 12 is a flowchart illustrating a procedure of a tire performance prediction method according to the second embodiment. FIGS. 13 and 14 are diagrams for explaining a tire performance prediction method according to the second embodiment. Step S201, step S202, and step S203 of the tire performance prediction method according to the present embodiment are a first model creation procedure, a model combination procedure, and an internal pressure load procedure, respectively, and steps S101, S102, and S103 of the first embodiment. Since it is the same as that, the description is omitted.

  In step S204, the model creation unit 51 extracts the displacement of the node of the first tire model 1 that is in contact with the first rim model 4 that is the first structure model. Step S204 corresponds to a displacement extraction procedure. For example, as shown in FIG. 9, the rim contact nodes N <b> 1 to N <b> 7 are nodes that contact the rim 4 </ b> A of the first rim model 4. Since the first tire model 1 is combined with the first rim model 4 and is loaded with internal pressure, the width of the bead portion is changed as compared with that before the first tire model 1 is combined with the first rim model 4.

  The displacement of the rim contact nodes N1 to N7 includes the positions of the rim contact nodes N1 to N7 (the position before the combination) before the first tire model 1 is combined with the first rim model 4, and the first tire model 1 to the first rim model 4. And the position of the rim contact nodes N1 to N7 (post-combination position) after the internal pressure is applied in combination. For the rim contact nodes N1 to N7, the model creation unit 51 stores the pre-combination position and the post-combination position in the storage unit 50m, and calculates the displacement of the rim contact nodes N1 to N7. The pre-combination position and the post-combination position are read from the storage unit 50m, the difference between the two is obtained, and this difference is stored in the storage unit 50m as the displacement of the rim contact nodes N1 to N7.

  Next, it progresses to step S205 and the model preparation part 51 carries out step S204 to the node (rim | limb contact nodes N1-N7) from which the displacement was extracted in step S204 of the 1st tire model 1 before combining with the 1st rim model 4. The displacement extracted in (1) is given as the forced displacement ΔL. Step S205 corresponds to a displacement applying procedure. In this case, the model creation unit 51 reads out the displacements of the rim contact nodes N1 to N7 stored in the storage unit 50m, and applies them to the corresponding rim contact nodes N1 to N7 as the forced displacement ΔL. Accordingly, the bead portion 2 of the first tire model 1 shown in FIG. 13 moves in a direction parallel to the Y axis that is the rotation axis of the first tire model 1 and so that both bead portions 2 approach each other. And as shown in FIG. 14, the 1st tire model 1 after giving forced displacement (DELTA) L moves to the position where the bead part 2 was combined with the 1st rim model 4, and the internal pressure was provided.

  In this embodiment, when the displacement of the rim contact nodes N1 to N7 is stored and stored in the storage unit 50m, and the performance is predicted again under different conditions using the same first tire model 1, The model creation unit 51 may read the displacement and the first tire model 1 from the storage unit 50m, and give them to the rim contact nodes of the first tire model 1 that predict the performance as the forced displacement ΔL. As a result, the procedure for combining the first tire model 1 and the first rim model 4, that is, the model combining procedure can be omitted, so that the calculation time can be reduced by that amount compared to the first embodiment.

  When the forced displacement ΔL is applied to the rim contact nodes N1 to N7, the model creation unit 51 stores the first tire model 1 after the applied displacement ΔL is stored in the storage unit 50m. Next, it progresses to step S206, and the model preparation part 51 reads the 1st tire model 1 after giving forced displacement (DELTA) L from the memory | storage part 50m, and after giving the forced displacement (DELTA) L of the read 1st tire model 1 The nodes (rim contact nodes N1 to N7) are constrained so that no relative displacement occurs. Step S206 corresponds to a restraint procedure. For example, in the example shown in FIG. 14, the rim contact nodes in contact with the rims 4 </ b> A and 4 </ b> B of the first rim model 4 in the bead portion 2 of the first tire model 1 are restrained so that relative displacement does not occur. To do.

  When the model creation unit 51 stores the first tire model 1 in which the rim contact nodes are constrained in the storage unit 50m, the model creation unit 51 proceeds to step S207. In step S207, the model creation unit 51 applies an internal pressure to the first tire model 1 after restraining the rim contact nodes to form a second tire model, and stores this in the storage unit 50m. Step S207 corresponds to a second model creation procedure. The internal pressure is the same size as the value of the internal pressure applied in step S203. Next, it progresses to step S208 and the analysis part 52 estimates a tire performance by performing a rolling analysis, a deformation | transformation analysis, etc. based on the 2nd tire model obtained by step S207. Since the tire performance prediction is the same as step S106 of the first embodiment, the description thereof is omitted.

  Compared with the tire performance prediction method according to the first embodiment, the tire performance prediction method according to the present embodiment adds a displacement extraction procedure and a displacement provision procedure, and therefore the calculation time increases accordingly. However, as compared with the technique disclosed in Patent Document 2, it is not necessary to consider the contact between the tire model and the rim model in the analysis in the tire performance simulation, so that the time required for the calculation can be reduced accordingly.

(Evaluation example)
The cornering performance of the tire was evaluated by the tire performance prediction method according to the present invention and the tire performance prediction method according to the comparative example. The present invention uses the tire performance prediction method according to the first embodiment. Comparative Example 1 is a method disclosed in Patent Document 2, that is, evaluation in a state where a tire model is combined with a rim model, and Comparative Example 2 is a method disclosed in Patent Document 1, that is, a tire model. This is an evaluation in a state in which the bead portion is forcibly displaced to the width of the rim to restrain the relative displacement. The evaluated tire has a tire size of 225 / 50R18 and a road index of 95W. The air pressure is 210 kPa, the load is 4.6 kN, and the speed is 10 km / h. Table 1 shows the evaluation results of the cornering power (CP), and Table 2 shows the evaluation results of the calculation time. The cornering power (CP) and calculation time are indicated by an index display in which the result obtained by the analysis is converted with the result of Comparative Example 1 being 100. The closer the evaluation value of the cornering power (CP) is to 100, the higher the calculation accuracy, and the smaller the evaluation value of the calculation time, the shorter the calculation time.

  As can be seen from the results in Table 1, the evaluation value of the present invention is closer to 100 than that of Comparative Example 2, so that the calculation accuracy is higher than that of Comparative Example 2 and is comparable to Comparative Example 1. Thus, the present invention can secure sufficient calculation accuracy. From the results in Table 2, the present invention has the longest calculation time until the creation of the two-dimensional model is completed (in the present invention, the calculation time until the above-described second tire model is completed). In addition to the method of Comparative Example 1, the present invention executes a procedure for restraining the nodes of the tire model in contact with the rim model and a procedure for releasing the contact of the restrained nodes with the rim model. It will take time.

  On the other hand, using the three-dimensional model (corresponding to the evaluation tire model) created from the two-dimensional model, the calculation time until the calculation of the analysis for obtaining the cornering power (CP) is completed is the shortest in Comparative Example 2. The present invention is about 60% of Comparative Example 1. Thus, unlike the comparative example 1, the present invention does not need to consider the contact between the tire model and the rim model, so that the calculation time required for the analysis using the three-dimensional model is significantly larger than the comparative example 1. Shortened.

  The total calculation time is an exponential display of the total calculation time required to create the two-dimensional model and the calculation time until the calculation for calculating the cornering power (CP) using the three-dimensional model is completed. It is. In the present invention, it takes a little time to create a two-dimensional model, but the creation time of the two-dimensional model occupies the entire time including the end of the analysis using the three-dimensional model. In addition, since the present invention does not need to consider the contact between the tire model and the rim model, the calculation time required for the analysis using the three-dimensional model can be shortened. Thus, the present invention can shorten the time from the creation of the two-dimensional model to the end of the analysis for the performance evaluation of the tire to the same level as in the comparative example 2 with respect to the comparative example 1. As described above, according to the present invention, when predicting the performance of a tire combined with a structure using a computer, it is possible to suppress a decrease in prediction accuracy of the tire performance while reducing the time required for calculation.

  As described above, the tire performance prediction method and the tire performance prediction computer program according to the present invention are useful for predicting tire performance using a computer.

It is sectional drawing which shows the meridional section which passes along the rotating shaft of a tire. It is explanatory drawing which shows the structure of the tire performance prediction apparatus which concerns on Embodiment 1. FIG. 3 is a flowchart illustrating a procedure of a tire performance prediction method according to the first embodiment. It is a perspective view which shows a tire model. It is a perspective view which shows a wheel model. It is a figure for demonstrating the performance prediction method of the tire which concerns on Embodiment 1. FIG. It is a figure for demonstrating the performance prediction method of the tire which concerns on Embodiment 1. FIG. It is a figure for demonstrating the performance prediction method of the tire which concerns on Embodiment 1. FIG. It is a figure for demonstrating the performance prediction method of the tire which concerns on Embodiment 1. FIG. It is a figure for demonstrating the performance prediction method of the tire which concerns on Embodiment 1. FIG. It is a schematic diagram which shows the state which is estimating the performance of a tire in the tire performance prediction method which concerns on Embodiment 1. FIG. 5 is a flowchart illustrating a procedure of a tire performance prediction method according to a second embodiment. It is a figure for demonstrating the performance prediction method of the tire which concerns on Embodiment 2. FIG. It is a figure for demonstrating the performance prediction method of the tire which concerns on Embodiment 2. FIG.

Explanation of symbols

1 tire model (first tire model)
1E Tire model for evaluation 1S 2nd tire model 2 Bead part 4 Rim model (1st rim model)
4A, 4B Rim 50 Tire performance prediction device 50m Storage unit 50p Processing unit 51 Model creation unit 52 Analysis unit 100 Tire

Claims (10)

A tire and a structure combined with the tire are divided into a plurality of minute elements composed of a plurality of nodes, and a first model for creating a first tire model and a first structure model that can be analyzed by a computer Creation procedure and
A model combination procedure for combining the first tire model and the first structure model;
An internal pressure loading procedure for applying an internal pressure to the first tire model;
A restraint procedure for restraining the nodes of the first tire model that are in contact with the first structure model so that relative displacement does not occur;
A second model creation procedure in which the contact between the first structure model and the first tire model is released, and the first tire model after the contact is released is used as a second tire model;
A performance prediction procedure for predicting the performance of the tire based on the second tire model;
A method for predicting tire performance, comprising: A tire and a structure combined with the tire are divided into a plurality of minute elements composed of a plurality of nodes, and a first model for creating a first tire model and a first structure model that can be analyzed by a computer Creation procedure and
A model combination procedure for combining the first tire model and the first structure model;
An internal pressure loading procedure for applying an internal pressure to the first tire model;
A displacement extraction procedure for extracting a displacement of a node of the first tire model in contact with the first structure model;
A displacement applying procedure for applying the displacement as a forced displacement to the node from which the displacement is extracted of the first tire model before being combined with the first structure model;
A constraining procedure for constraining the nodes after applying the forced displacement so that relative displacement does not occur;
A second model creation procedure in which an internal pressure is applied to the first tire model after restraint to form a second tire model;
A performance prediction procedure for predicting the performance of the tire based on the second tire model;
A method for predicting tire performance, comprising: A first model creation procedure for creating a first tire model and a first rim model that can be analyzed by a computer by dividing a tire and two rims included in a wheel into a plurality of minute elements composed of a plurality of nodes. When,
A model combination procedure for combining the bead portion of the first tire model with the first rim model;
An internal pressure loading procedure for applying an internal pressure to the first tire model;
A restraint procedure for restraining the nodes of the first tire model in contact with the first rim model so as not to cause relative displacement;
A second model creation procedure in which contact between the first rim model and the first tire model is released, and the first tire model after the contact is released is used as a second tire model;
A performance prediction procedure for predicting the performance of the tire based on the second tire model;
A method for predicting tire performance, comprising: A first model creation procedure for creating a first tire model and a first rim model that can be analyzed by a computer by dividing a tire and two rims included in a wheel into a plurality of minute elements composed of a plurality of nodes. When,
A model combination procedure for combining the bead portion of the first tire model with the first rim model;
An internal pressure loading procedure for applying an internal pressure to the first tire model;
A displacement extraction procedure for extracting a displacement of a node of the first tire model in contact with the first rim model;
A displacement applying procedure for applying the displacement as a forced displacement to the node from which the displacement is extracted of the first tire model before being combined with the first rim model;
A constraining procedure for constraining the nodes after applying the forced displacement so that relative displacement does not occur;
A second model creation procedure in which an internal pressure is applied to the first tire model after restraint to form a second tire model;
A performance prediction procedure for predicting the performance of the tire based on the second tire model;
A method for predicting tire performance, comprising:   5. The tire performance prediction method according to claim 3, wherein, in the second model creation procedure, contact with the first rim model is considered for nodes other than the nodes constrained by the restraining procedure. In the restraint procedure,
The node on the rotation axis of the first tire model, which is a node existing on the equator plane of the first tire model, is also constrained so that relative displacement does not occur. The tire performance prediction method described in 1. In the restraint procedure,
6. A node on the rotation axis of the first tire model, which is a node on the equator plane of the first tire model, is also constrained so that relative displacement does not occur. The tire performance prediction method according to any one of the above.   The tire performance prediction method according to claim 7, wherein at least one of a mass of the rim and an inertia moment of the rim is set at the rotation axis center node.   9. The system according to claim 1, wherein the second tire model is a two-dimensional model, and the tire model used for predicting the performance of the tire is a three-dimensional model created from the second tire model. 2. The tire performance prediction method according to item 1.   A computer program for predicting tire performance, which causes a computer to execute the method for predicting tire performance according to any one of claims 1 to 9.

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