JP2012112670A - Creation method of tire wheel assembly model, computer program for creating tire wheel assembly model and simulation method of tire wheel assembly, and creation device for tire wheel assembly model - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a tire wheel assembly model having a more exact shape to be created in a shorter period of time.SOLUTION: A creation method of a tire wheel assembly model includes: a tire model creation step in which a computer divides an analysis object tire into a plurality of elements to create a tire model; a rim model creation step in which the computer divides a part in contact with the tire into elements to create a rim model; a wheel model creation step in which the computer divides an analysis object wheel model into a plurality of elements to create a wheel model; a coupling step for performing a contact calculation of the tire model and the rim model and coupling the tire model and the rim model together; and an embedding step for embedding the rim model in the wheel model.

Description

  The present invention relates to a technique for creating a tire model used when executing tire vibration analysis using a computer.

  In order to shorten the tire development period and reduce the development cost, in recent years, a technique for evaluating the performance of the tire by simulation using a computer has been used. Furthermore, in order to analyze the performance of the tire, there is a technique for evaluating the performance of the tire with the tire mounted on the wheel. Patent Document 1 is divided in the tire circumferential direction, and is given an application condition that represents at least one of tire circumferential non-uniformity, rotational speed, load, and internal pressure for at least one physical quantity of mass, rigidity, and shape. A technique is described in which a tire model is defined as a possible model, a tire wheel model divided into a plurality of elements is defined, an assembly model is created by combining the tire model and the tire wheel model, and analysis is performed. Patent Document 2 describes a technique for creating and analyzing a tire / wheel assembly model by creating a tire model and a wheel model, allowing the models to overlap and combining them.

JP 2007-83925 A JP 2007-131206 A

  In this way, when creating a tire / wheel assembly model that combines a tire model and a wheel model and analyzing the tire / wheel assembly, a fitting calculation is performed to combine the tire model and the wheel model. The shape of the tire model at the time of assembly, specifically, the shape when the tire is filled with air (when inflated) is calculated.

  Here, if the number of divisions of the wheel model element to be analyzed is reduced, the shape of the rim part of the model will be different from that of the actual rim, and the result of the fitting calculation and the shape during actual assembly (when assembling the rim) Deviation occurs between the two. For this, the shape of the tire can be calculated more accurately by increasing the number of divisions of the wheel model, dividing the wheel model into smaller elements, and accurately expressing the wheel model. However, when the number of divisions of the wheel model is increased, there is a problem that the model to be calculated increases, the amount of calculation increases, and it takes time to create the tire / wheel assembly model.

  The present invention has been made in view of such a problem, and a tire / wheel assembly model creation method and a tire capable of creating a tire / wheel assembly model having a more accurate shape in a shorter time. It is an object to provide a computer program for creating a wheel assembly model, a simulation method for a tire / wheel assembly, and a tire / wheel assembly model creating apparatus.

  In order to solve the above-described problems and achieve the object, a method for creating a tire / wheel assembly model according to the present invention is such that a computer divides a tire to be analyzed into a plurality of elements and creates a tire model. A tire model creating step, the computer divides a portion in contact with the tire into elements, a rim model creating step for creating a rim model, and the computer divides a wheel model to be analyzed into a plurality of elements; A wheel model creating step for creating a wheel model; a contact step for performing contact calculation between the tire model and the rim model; and coupling the tire model and the rim model; and embedding the rim model in the wheel model; It is characterized by including. Thereby, it is possible to create a tire / wheel assembly model having a more accurate shape in a shorter time.

  In the embedding step, the rim model combined with the tire model in the combining step is preferably embedded in the wheel model.

  In the combining step, it is preferable that the rim model embedded in the wheel model is combined with the tire model in the embedding step.

  In the rim model creation step, the average dimension of the elements constituting the contact portion, which is a portion that is in contact with or possibly in contact with the tire model, is calculated as the average of the elements in the region corresponding to the contact portion of the wheel model. It is preferable to make it smaller than the dimension. Thereby, contact calculation can be performed with higher accuracy.

  Further, in the rim model creation step, it is preferable that an average dimension of an element constituting a contact portion, which is a portion that is in contact with or possibly in contact with the tire model, is smaller than an average dimension of elements other than the contact portion. . Thereby, calculation time can be shortened.

  Moreover, it is preferable that the said rim model creation step creates the model comprised only by the contact part which is a part which contacts or may contact the said tire model as said rim model. Thereby, calculation time can be shortened more.

  Here, it is preferable that the rim model creation step has a shape in which an end portion of the rim model in the meridional section is folded back inward in the tire radial direction. Thereby, the shape of the tire can be calculated more accurately, and the convergence of the calculation can be further improved.

  In the coupling step, it is preferable to perform contact calculation with a setting in which a static friction coefficient between the rim model and the tire model is larger than a dynamic friction coefficient between the rim model and the tire model. Thereby, contact calculation can be performed with higher accuracy.

  In the coupling step, it is preferable to perform contact calculation using the dynamic friction coefficient as a value that changes in accordance with a relative sliding speed between the tire model and the rim model. Thereby, contact calculation can be performed with higher accuracy.

  Further, it is preferable that the coupling step is set so that the tire model does not slip with respect to the rim model after contact calculation is performed and the tire model is fitted to the rim model. Thereby, analysis of a tire and wheel assembly model can be performed more correctly.

  In the wheel model, the mass, the position of the center of gravity, the moment of inertia, and the eigenvalue are preferably the same as the mass, the position of the center of gravity, the moment of inertia, and the eigenvalue of the wheel model in which the rim model is embedded. Thereby, analysis of a tire and wheel assembly model can be performed more correctly.

  Preferably, the method further includes a tire cavity creating step for modeling a region surrounded by a tire and a wheel as a tire cavity, and a cavity coupling step for coupling the tire cavity with either a tire model or a rim model. As a result, more analyzes can be performed as a tire / wheel assembly model.

  In the tire model creation step, the tire model is created as a two-dimensional tire model having a meridional section, and after the process of the joining step is completed, the two-dimensional tire model is developed in the circumferential direction to obtain a three-dimensional tire model. A tire model is created, and in the rim model creating step, the rim model is created as a two-dimensional rim model having a meridional section, and after the process of the joining step is completed, the two-dimensional rim model is developed in a circumferential direction to obtain a three-dimensional model. It is preferable to create a rim model. Thereby, the calculation amount of contact calculation can be reduced more.

  In order to solve the above-described problems and achieve the object, a computer program for creating a tire / wheel assembly model according to the present invention uses the method for creating a tire / wheel assembly model described above in a computer. It is made to perform. Thereby, it is possible to create a tire / wheel assembly model having a more accurate shape in a shorter time.

  In order to solve the above-described problems and achieve the object, a simulation method for a tire and wheel assembly according to the present invention is produced by a method for creating a tire and wheel assembly model according to any one of the above. The analysis is executed using the tire / wheel assembly model. Thereby, it is possible to create a tire / wheel assembly model having a more accurate shape in a shorter time.

  In order to solve the above-described problems and achieve the object, a tire / wheel assembly model creation device according to the present invention divides a tire to be analyzed into a plurality of elements to create a tire model, and the tire A part that makes contact with the wheel, creating a rim model, dividing the wheel model to be analyzed into a plurality of elements, creating a wheel model, and contact calculation between the tire model and the rim model And a contact calculation unit that combines the tire model and the rim model, and an embedding processing unit that embeds the rim model in the wheel model. Thereby, it is possible to create a tire / wheel assembly model having a more accurate shape in a shorter time.

  The present invention makes it possible to create a tire / wheel assembly model having a more accurate shape in a shorter time.

FIG. 1 is a meridional sectional view of a tire / wheel assembly. FIG. 2 is an explanatory diagram illustrating an analysis apparatus that executes a tire / wheel assembly model creation method and a tire / wheel assembly simulation method according to the present embodiment. FIG. 3 is a perspective view showing a tire / wheel assembly model. FIG. 4 is a perspective view showing a tire model. FIG. 5 is a cross-sectional view showing a meridional cross-sectional model for creating a tire model. FIG. 6 is a perspective view showing a rim model. FIG. 7 is a cross-sectional view showing a meridional cross-sectional model for creating a rim model. FIG. 8 is a perspective view showing a wheel model. FIG. 9 is a cross-sectional view showing a meridional cross-sectional model of the rim portion of the wheel model. FIG. 10 is a flowchart showing the procedure of the tire / wheel assembly analysis method according to this embodiment. FIG. 11 is a cross-sectional view showing the shape of both ends of the rim surface of the wheel model. FIG. 12 is a schematic diagram illustrating an example of a surface shape of a tire model when air is filled. FIG. 13 is a cross-sectional view showing another example of the rim model. FIG. 14 is a perspective view showing another example of the rim model. FIG. 15 is a cross-sectional view showing another example of the rim model. FIG. 16 is a cross-sectional view showing another example of the rim model. FIG. 17 is a cross-sectional view showing another example of the rim model. FIG. 18 is a schematic diagram showing another example of a method for creating a tire / wheel assembly model. FIG. 19 is a perspective view showing another example of a wheel model. 20 is a cross-sectional view showing a meridional cross-sectional model of the rim portion of the wheel model shown in FIG. FIG. 21 is a perspective view showing another example of the wheel model. 22 is a cross-sectional view showing a meridional cross-sectional model of the rim portion of the wheel model shown in FIG. FIG. 23 is a perspective view showing another example of the wheel model. 24 is a cross-sectional view showing a meridional cross-sectional model of the rim portion of the wheel model shown in FIG.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the content of the form (henceforth embodiment) for implementing the invention demonstrated below. The following constituent elements include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

  FIG. 1 is a meridional sectional view of a tire / wheel assembly. As shown in FIG. 1, the tire / wheel assembly 10 includes a tire 1 and a wheel 12 fitted into the tire 1. The tire 1 is an annular structure that rotates about a rotation axis (Y axis), and a meridional section having a similar shape is developed around the center axis in the circumferential direction. 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, the layer of the reinforcing cord made of a cord material such as metal fiber or 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 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 ground contact surface (tread) 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, and the tread. A groove 7 is formed on the ground surface G side of the cap tread 6. This improves drainage during rainy weather. 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 wheel 12 is made of an elastic body and is connected to a vehicle shaft or the like. Further, the wheel 12 has a radially outer surface in contact with a radially inner surface of the tire 1. The wheel 12 has a rim surface 14 on the outer surface in the tire radial direction. The tire / wheel assembly 10 is a space in which the inner peripheral surface of the tire 1 and the rim surface 14 are closed, and the tire 1 is in an inflated state by being filled with air. Next, a method for creating a tire / wheel assembly model and an apparatus for executing analysis of the tire / wheel assembly according to the present embodiment will be described.

  FIG. 2 is an explanatory diagram illustrating an analysis apparatus that executes a tire / wheel assembly model creation method and a tire / wheel assembly simulation method according to the present embodiment. The tire / wheel assembly model creation method and the tire / wheel assembly analysis method (simulation method) according to this embodiment are performed by a tire / wheel assembly analysis apparatus (hereinafter referred to as an analysis apparatus) 50 shown in FIG. realizable. The analysis device 50 is a computer and includes a processing unit 52 and a storage unit 54 as shown in FIG. An input / output device 51 is connected to the analysis device 50, and the shape of a tire model, a rim model, and a wheel model constituting a tire / wheel assembly model as an analysis model by an input means 53 provided therein. Various physical property values, boundary conditions in tire performance analysis, the number of modes to be analyzed, and the like are input to the processing unit 52 and the storage unit 54. Here, the analysis device 50 of the present embodiment has both a function as a creation device for creating a tire / wheel assembly model and a function as an analysis device for analyzing a tire / wheel assembly model. It is not limited to this. The analysis device 50 may be a device having only a function as a creation device for creating a tire / wheel assembly model. In this case, the analysis device 50 can also be said to be a model creation device.

  An input device such as a keyboard and a mouse can be used for the input means 53. The storage unit 54 stores a computer program that can realize the tire model creation method according to the present embodiment, other computer programs, a data table, a data map, and the like. The storage unit 54 is a hard disk device, a magneto-optical disk device, a nonvolatile memory such as a flash memory (a storage medium that can be read only such as a CD-ROM), or a volatile memory such as a RAM (Random Access Memory). The memory can be configured by a combination of these, or a combination thereof.

  A tire / wheel assembly model creation computer program capable of realizing the tire / wheel assembly model creation method according to the present embodiment is a combination of the computer program already recorded in the computer system and the tire according to the present invention.・ Analysis of wheel assemblies can be realized. A combination of these programs or a program that can realize the same processing as these programs is a computer program for analysis of a tire and wheel assembly that can realize a method for analyzing a tire and wheel assembly. Further, the computer program for creating the tire / wheel assembly model and / or the computer program for analyzing the tire / wheel assembly according to the present embodiment is recorded on a computer-readable recording medium and recorded on the recording medium. A computer program for creating a tire / wheel assembly model and / or a computer program for analyzing a tire / wheel assembly is read into a computer system and executed. Thus, the tire / wheel assembly model creation method and / or the tire / wheel assembly analysis method according to the present invention may be realized. Note that the “computer system” herein includes an OS (Operating System) and hardware such as peripheral devices.

  The processing unit 52 includes a model creation unit 52a, a contact calculation unit 52b, an embedding processing unit 52c, and an analysis unit 52d. The model creation unit 52a creates a tire model, a rim model, and a wheel model that constitute a tire / wheel assembly to be analyzed, and further divides each created model into a plurality of elements, A tire model, a rim model, and a wheel model are created and stored in the storage unit 54. The tire model, the rim model, and the wheel model are analysis models that can be variously analyzed by being handled by a computer. The analysis model includes a mathematical model and a mathematical discretization model (the same applies to the following examples). The contact calculator 52b calculates the contact between the tire model created by the model creator 52a and the rim model. That is, the deformation that occurs when the tire model comes into contact with the rim model is calculated. The embedding processing unit 52c performs processing for embedding the rim model created by the model creating unit 52a in the wheel model. That is, the embedding processing unit 52c performs a process of superimposing and associating the rim model and the wheel model. The analysis unit 52d analyzes the created tire / wheel assembly. The analysis unit 52 performs vibration analysis, acoustic analysis, ground contact analysis, and the like of the tire / wheel assembly as the analysis. As the analysis, either dynamic analysis or static analysis can be performed.

  The processing unit 52 includes, for example, a CPU (Central Processing Unit) and a memory. The processing unit 52 incorporates a tire / wheel assembly model creation program into the processing unit 52 based on the tire model, rim model, wheel model, and the like created by the model creation unit 52a. Read into memory and perform calculations. At that time, the processing unit 52 appropriately stores a numerical value in the middle of the calculation in the storage unit 54, and reads the numerical value stored in the storage unit 54 to advance the calculation. The processing unit 52 may realize the function by dedicated hardware instead of the computer program for creating the tire / wheel assembly model. Note that the processing unit 52 performs the calculation in the memory similarly when analyzing the created tire / wheel assembly model, that is, when analyzing the tire / wheel assembly model, and stores it in the storage unit 54 as necessary. Saves the numerical value and advances the calculation.

  As the display means 55, for example, a liquid crystal display device can be used. The determination result can also be output to a printer provided as necessary. The storage unit 54 that stores the various types of information described above may be in another device (for example, a database server). For example, the analysis device 50 may access the processing unit 52 and the storage unit 54 by communication from a terminal device including the input / output device 51. Next, a tire / wheel assembly model creation method and a tire / wheel assembly analysis method according to this embodiment will be described.

  The construction of the tire / wheel assembly to be created will be described with reference to FIGS. Here, FIG. 3 is a perspective view showing a tire / wheel assembly model. FIG. 4 is a perspective view showing a tire model, and FIG. 5 is a cross-sectional view showing a meridional section model for creating a tire model. FIG. 6 is a perspective view showing a rim model, and FIG. 7 is a cross-sectional view showing a meridional section model for creating a rim model. FIG. 8 is a perspective view showing a wheel model, and FIG. 9 is a cross-sectional view showing a meridional section model of a rim portion of the wheel model.

  In the tire / wheel assembly model creation method, as shown in FIG. 3, a tire / wheel assembly 100 having a tire model 102, a wheel model 104, and a rim model 106 is created. In FIG. 3, the rim model 106 is sandwiched between the tire model 102 and the wheel model 104 and cannot be seen.

  A tire / wheel assembly 100 having a tire model 102, a wheel model 104, and a rim model 106 is a model used for analysis using a numerical analysis method such as a finite element method or a finite difference method. In this embodiment, a finite element method (FEM) is used for the analysis of the tire / wheel assembly 100. The analysis method applicable to the method for creating the tire / wheel assembly model according to the present embodiment is not limited to the finite element method, but also includes a finite difference method (FDM), a boundary element method (BEM), and the like. Can 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 preferably applied particularly to a structure such as a tire / wheel assembly.

  Next, as shown in FIG. 4, the tire model 102 is a three-dimensional analysis model having a plurality of elements. Each element has a plurality of nodes. The Y axis is the rotation axis of the tire model 102, and the Z axis is an arbitrary axis orthogonal to the rotation axis (Y axis) (for example, when the ground analysis is performed using the tire model 102, the road surface to be grounded) Orthogonal axes). The X axis is an axis orthogonal to the Y axis and the Z axis.

  The elements included in the tire model 102 are, for example, solid elements such as tetrahedral solid elements, pentahedral solid elements, and hexahedral solid elements in a three-dimensional body, shell elements such as triangular shell elements, rectangular shell elements, and surface elements. It is desirable to make it an element that can be handled. In the process of analysis, the elements thus divided are identified one by one using the two-dimensional coordinate in the two-dimensional model and using the three-dimensional coordinate in the three-dimensional model.

  The meridional section model 102a shown in FIG. 5 is an analysis model of the meridional section of a tire to be analyzed (for example, the tire 1 shown in FIG. 1). The meridional section model 102a is a two-dimensional analysis model having a plurality of elements. Each element has a plurality of nodes. Elements of the meridional section model 102a include a triangular element, a quadrilateral element, and the like. In the present embodiment, the model creation unit 52a makes the meridional section model 102a one round (360 degrees or 2 × π) in the circumferential direction around an axis that serves as the rotation axis (Y axis) of the tire model 102. By developing, the tire model 102 shown in FIG. 4 is created.

  Next, the rim model 106 is also a model of a wheel rim (for example, the rim surface 14 shown in FIG. 1) of the tire / wheel assembly to be analyzed. As shown in FIG. 6, a three-dimensional model having a plurality of elements is used. It is an analysis model. Each element has a plurality of nodes. The elements included in the rim model 106 can also be composed of various elements in the same manner as the tire model 102. In the process of analysis, the elements thus divided are identified one by one using the two-dimensional coordinate in the two-dimensional model and using the three-dimensional coordinate in the three-dimensional model.

  The meridional section model 106a shown in FIG. 7 is an analysis model of the meridional section of the rim surface of the wheel of the tire / wheel assembly to be analyzed. The meridional section model 106a is a two-dimensional analysis model having a plurality of elements. Each element has a plurality of nodes. Of the plurality of elements constituting the rim model 106a, the elements surrounded by the area 108a and the area 108b are elements that come into contact with the tire model 102 (elements that may come into contact). The region 108a is a region including one end portion in the direction parallel to the rotation axis in the meridional section model 106a. The region 108b is a region including the other end of the meridional model 106a in the direction parallel to the rotation axis. The elements included in the meridional section model 106a are shell elements and the like configured in one dimension (line segment). That is, the meridional cross-section model 106a is composed of a line segment having no thickness. In the present embodiment, the model creation unit 52a develops the meridional section model 106a for one round (360 degrees or 2 × π) in the circumferential direction around an axis that serves as the rotation axis (Y axis) of the rim model 106. As a result, the rim model 106 shown in FIG. 6 is created.

  Next, the wheel model 104 is a three-dimensional analysis model that includes a spoke portion, a flange portion, a rim portion, and the like, and is composed of elements obtained by dividing the spoke portion, the flange portion, and the rim portion into finite pieces. Each element has a plurality of nodes. The elements included in the wheel model 104 can also be composed of various elements in the same manner as the tire model 102. In the process of analysis, the elements thus divided are identified one by one using the two-dimensional coordinate in the two-dimensional model and using the three-dimensional coordinate in the three-dimensional model.

  A meridional section model 104a shown in FIG. 9 is an analysis model of a meridional section of a wheel of a tire / wheel assembly to be analyzed. The meridional section model 104a is a two-dimensional analysis model having a plurality of elements. Each element has a plurality of nodes. Elements that the meridional section model 104a has are a triangular element, a quadrilateral element, and the like. In the present embodiment, the model creation unit 52a makes the meridional section model 104a one round (360 degrees or 2 × π) in the circumferential direction around an axis that serves as the rotation axis (Y axis) of the wheel model 104. By developing, the wheel model 104 shown in FIG. 8 is created.

  Next, a processing procedure of a tire / wheel assembly model creation method and a tire / wheel assembly analysis method will be described with reference to FIG. FIG. 10 is a flowchart showing the procedure of the tire / wheel assembly analysis method according to this embodiment. As described above, the processing illustrated in FIG. 10 is performed by performing processing in each unit of the processing unit 52.

  First, in step S12, the processing unit 52 creates the tire model 102, the rim model 106, and the wheel model 104 as described above by the model creation unit 52a. Note that the model creation unit 52a reads out a model created in advance and stored in the storage unit 54, so that even if a model to be used is created, processing is performed based on the input shape and condition. A model may be created.

  After creating the tire model 102, the rim model 106, and the wheel model 104 in step S12, the processing unit 52 performs contact calculation between the tire model and the rim model by the contact calculation unit 52b in step S14. That is, the processing unit 52 calculates the shape of the tire model 102 in a state where the tire model 102 is mounted on the rim model 106.

  After performing the contact calculation in step S14, the processing unit 52 embeds the rim model in the wheel model by the embedding processing unit 52c as step S16. That is, the processing unit 52 superimposes and integrates the rim model 106 on the corresponding position (rim surface) of the wheel model 104. The processing unit 52 brings the tire model 102 into contact with the rim model 106 in step S14 and embeds the rim model 106 in the wheel model 104 in step S16, so that the tire model 102 is attached to the wheel model 104 via the rim model 106. That is, the tire / wheel assembly model 100 is created.

  After performing the embedding process in step S16, the processing unit 52 analyzes the tire / wheel assembly by the analysis unit 52d in step S18. That is, the processing unit 52 performs various calculations and analyzes based on the created tire / wheel assembly model 100 and the set conditions. Note that the processing unit 52 may display the analysis result on the display unit 55 or may output it using another output unit. When the analysis is completed, the processing unit 52 ends this processing.

  As described above, the analysis device 50 performs processing in each unit, and executes a tire / wheel assembly model creation method and a tire / wheel assembly analysis method, so that the tire model 102 and the wheel model 104 are processed. In addition, a rim model 106 is created, and contact calculation is performed between the tire model 102 and the rim model 106. As described above, by performing contact calculation of the tire model 102 (deformation of the tire caused by being attached to the rim) with the rim model 106, it is possible to reduce the number of target elements when the contact calculation is performed. Thereby, the processing amount by the contact calculation of step S14 can be reduced.

  In addition, since the analysis device 50 models the surface of the rim model 106 that contacts the tire model 102, an increase in the number of elements can be suppressed even if an accurate rim shape model is created. As a result, even if the rim surface in contact with the tire is modeled with high accuracy, that is, with finer elements, contact calculation can be executed while suppressing an increase in the amount of calculation. Thereby, the contact calculation of the tire model 102 can be performed with high accuracy, and an increase in the calculation amount can be suppressed.

  Further, the analysis device 50 can create the tire / wheel assembly model 100 by embedding the wheel model 104 in the rim model 106 without executing contact calculation with the tire model 102. Further, the wheel model 104 may be modeled with elements necessary for the analysis executed in step S18 by not being a target for contact calculation. That is, any model that can express the characteristics of the wheel itself may be used as the wheel model. In other words, by not using the wheel model 104 for contact calculation, it is not necessary to model the shape of the rim surface or the like with high accuracy in order to accurately analyze the deformation of the mounted tire, and the number of model elements is reduced. can do.

  As described above, the analysis device 50 can accurately execute the tire contact calculation even when a low-accuracy model is used as the wheel model. Thereby, the analysis of the tire / wheel assembly can be executed with higher accuracy. Further, by using a rim model as a model used for contact calculation, tire contact calculation can be executed accurately and the amount of contact calculation can be reduced. Further, as the rim model, a model that can calculate the contact calculation of the tire model more accurately can be used, and a model having a shape different from the shape of the wheel model can also be used. In other words, by generating a rim model in consideration of the deviation caused by the numerical calculation process, the occurrence of deviation between the contact calculation result and the actual mounting result can be suppressed.

  Here, FIG. 11 is a cross-sectional view showing the shape of both ends of the rim surface of the wheel model, and FIG. 12 is a schematic diagram showing an example of the surface shape of the tire model during air filling. FIG. 11 shows a state in which the rim surface is folded around an axis parallel to the tire radial direction and the rim surfaces at both ends are overlapped. In the wheel model shown in FIG. 11, the shape of the rim surface 112 at one end in the direction parallel to the rotation axis is different from the shape of the rim surface 114 at the other end.

  As described above, even when a wheel model having an asymmetric rim surface is used, by performing contact calculation using the rim model as in the present embodiment, as shown in the profile 122 of FIG. The deformed tire shape can be calculated. On the other hand, when the contact calculation with the tire model is performed using the wheel model without using the rim model, a shape deformed asymmetrically as shown in the profile 124 is obtained. Here, the profile 122 and the profile 124 are profiles in a state where the tire model is inflated. That is, it is a result of calculating the profile (surface shape) of the tire model in a state where the tire model is brought into contact with the rim model or the wheel model and further filled with air at a predetermined internal pressure. Note that the profile obtained by actually inflating the tire has a shape deformed symmetrically in the same manner as the profile 122. Thus, by calculating the contact using the rim model, it is possible to calculate a tire profile that is closer to the actual condition even if the wheel model has an asymmetric shape.

  Further, since the rim model is only embedded in the wheel model, the calculation executed in the embedding process can be executed with a small amount of calculation.

  Here, in the above embodiment, the contact calculation is performed in step S14, and then the embedding process is performed in step S16. However, the present invention is not limited to this, and the steps S14 and S16 may be executed in the reverse order. Good.

  Further, the rim model does not need to overlap the wheel model, and the rim model may have a shape in contact with the outer periphery of the wheel model, or may have a shape that is disposed at a position outside the wheel model in the tire radial direction. The rim model may be a model that can execute contact calculation with the tire model, and may not have specific information such as mass and elastic coefficient. In addition, since the deformation due to contact with the rim surface of the tire model is executed by calculation with the rim model, the wheel model may not have the shape information of the rim surface. Further, a part of the wheel model and a part of the tire model may overlap each other.

  Further, the rim model 106 is a portion of the contact portion with the tire model 102, that is, a portion surrounded by a region corresponding to the region 108 a and the region 108 b of the wheel model 104 in an average dimension of a portion surrounded by the region 108 a and the region 108 b. Preferably it is smaller than the average dimension of the elements. For example, if the average dimension of the element surrounded by the region of the wheel model 104 is 5.8 mm, the average dimension of the element surrounded by the region of the rim model 106 is preferably 4.6 mm. Thereby, the contact calculation of the tire model 102 can be calculated more accurately than the case where the calculation is performed by contacting the wheel model 104. Note that the contact portion with the tire model 102 includes a region that may come into contact as described above, for example, a portion including a rim flange to a hump.

  Further, the rim model is not limited to the shape shown in FIGS. 6 and 7, and can be various shapes. Hereinafter, another example of the rim model will be described with reference to FIGS. 13 to 17. FIG. 13 is a cross-sectional view showing another example of the rim model. In the rim model 130 shown in FIG. 13, the average dimensions of the elements 134 a and 134 b surrounded by the contact portion with the tire model 102, that is, the regions 136 a and 136 b, are the other portions 132, that is, the regions 136 a and 136 b. It is smaller than the average dimension of the elements of the unenclosed portion 132. In this way, by making the size of each element constituting the portions 134a and 134b smaller than the size of each element constituting the portion 132, the contact portion with the tire is modeled in more detail, and The number of elements can be omitted. In other words, by increasing the element of the portion that does not contact the tire, the calculation amount of the portion that does not affect the contact calculation can be reduced. Thereby, calculation time can be shortened, maintaining the precision of contact calculation.

  Next, FIG. 14 is a perspective view showing another example of the rim model. A rim model 140 shown in FIG. 14 has a first contact portion 142 and a second contact portion 144. Here, the 1st contact part 142 is a part which modeled one edge part which contacts a tire model in a rim surface. The second contact portion 144 is a portion obtained by modeling the other end portion in contact with the tire model on the rim surface. That is, the rim model 140 is a model configured only with a portion that contacts the tire model (including a region that may be contacted by contact calculation). Since the rim model 140 models only the contact portion with the tire model, the number of elements for contact calculation can be reduced. Thereby, the number of elements to be calculated for contact calculation can be reduced, and the calculation time can be shortened.

  Here, the rim model has a shape in which the end in the direction parallel to the rotation axis (end in the meridional section) is folded back in the direction away from the tire model, that is, in the direction away from the tire model (inner side in the tire radial direction (center side)). ) Is preferably bent. Hereinafter, description will be made with reference to FIGS. 15 to 17. Here, FIGS. 15 to 17 are cross-sectional views showing other examples of the rim model. The rim model 150 shown in FIG. 15 has a shape in which ends 152a and 152b in a direction parallel to the rotation axis, that is, portions surrounded by the regions 154a and 154b, respectively, are bent toward the center in the tire radial direction. In this way, by folding the shape of the rim model 150 inward in the radial direction, the convergence of the contact calculation can be improved, and in particular, the convergence when the tire is deformed to the vicinity of the end of the rim can be improved. it can. Thereby, contact calculation with a tire model and a rim model can be performed more smoothly.

  Next, in the rim model 160 shown in FIG. 16, the end 162a and the end 162b in the direction parallel to the rotation axis, that is, the portions surrounded by the regions 164a and 164b are bent toward the center in the tire radial direction. It is. Note that the end portion 162a and the end portion 162b are portions added to both ends of a region where the rim surface is modeled. That is, the rim model 160 is obtained by adding end portions 162a and 162b to both ends of the rim model 106 described above. Convergence of contact calculation can also be improved by adding end portions 162a and 162b that are bent inward in the radial direction to a portion that does not actually have a rim surface, such as the rim model 160. Thereby, contact calculation with a tire model and a rim model can be performed more smoothly.

  Next, the rim model 170 shown in FIG. 17 has a first contact portion 172 and a second contact portion 174 corresponding to a portion of the rim surface that contacts the tire. Further, the first contact portion 172 has an end 177a on the tire center side in a direction parallel to the rotation axis (a portion surrounded by the region 179a) and an end 178a on the tire end side (a portion surrounded by the region 176a). The shape is bent toward the center in the tire radial direction. The second contact portion 174 also has a tire center side end 177b (a portion surrounded by the region 179b) and a tire end side end 178b (a portion surrounded by the region 176b) in a direction parallel to the rotation axis. The shape is bent toward the center in the tire radial direction. As described above, even when the rim model 170 is divided into the first contact portion 172 and the second contact portion 174, the contact calculation is performed by bending the end in the direction parallel to the rotation axis inward in the radial direction. Convergence can be improved. Thereby, contact calculation with a tire model and a rim model can be performed more smoothly.

  Moreover, it is preferable that the analysis device performs the contact calculation with the static friction coefficient set larger than the dynamic friction coefficient when performing the contact calculation with the tire model. In other words, the static friction coefficient, which is the friction coefficient of the portion where the rim model and the tire model are relatively stationary, is larger than the dynamic friction coefficient, which is the friction coefficient of the portion where the rim model and the tire model are relatively sliding. In addition, it is preferable to set the respective friction coefficients. Accordingly, a more accurate inflation shape can be calculated by contact calculation (fitting calculation for fitting the tire model to the rim model). That is, the movement (slip) of the tire model relative to the rim model calculated by contact calculation can be calculated more accurately. Thereby, the shape of the tire model in the state of being incorporated in the rim can be calculated more accurately.

  Furthermore, it is preferable that the analysis device performs contact calculation with a value that changes the dynamic friction coefficient in accordance with the relative sliding speed of the tire model and the rim model. Specifically, it is preferable to set the dynamic friction coefficient to be smaller as the sliding speed increases, and to increase the dynamic friction coefficient as the sliding speed decreases. As a result, when the bead portion of the tire model slips with respect to the rim model, the dynamic friction coefficient decreases as the sliding speed increases, so the relationship between the actual tire and the rim (wheel rim surface), that is, the bead portion and the rim model. It is possible to perform an analysis in consideration of the influence of the change in the friction force between the tires, and to calculate a more accurate inflation shape of the tire.

  Further, it is preferable that the analysis device does not slip, that is, does not move after the contact calculation is performed and the tire model is fitted to the rim model. That is, it is preferable to fix (combine) the contact position between the rim model and the tire model when the contact calculation is completed. Thereby, analysis of a tire and wheel assembly can be performed more appropriately.

  Various settings at the time of contact calculation between the tire model and the rim model are not limited to being set as conditions and setting values of the rim model. For example, it may be set as a condition for contact calculation or may be set as a condition such as a physical property value of a tire model.

  The wheel model and rim model have elastic modulus and material density so that the weight, center of gravity, moment of inertia, and eigenvalue of the wheel model are equivalent to the mass, center of gravity, moment of inertia, and eigenvalue of the wheel model in which the rim model is embedded. Is preferably defined. As a result, the tire / wheel assembly can be analyzed with higher accuracy. Specifically, by making the wheel model and the rim model satisfy the above relationship, the model in which the rim model is incorporated in the wheel model is also different from the case where only the wheel model is used (the natural frequency in each mode). ) Can be a similar value. That is, even when the rim model is provided, the characteristics of the wheel model can be set to the same characteristics as when the analysis is performed using only the wheel model.

  In addition, the model creation method and the analysis apparatus, when modeling a cavity inside the tire, that is, a region surrounded by the tire and the wheel, is a space surrounded by the tire model and the wheel model, or the tire model. It is preferable that the space surrounded by the rim model is modeled as a hollow model, and this hollow model is combined with any one of the tire model, the tire model, and the rim model. As a result, the cavity model can be accurately modeled and analyzed.

  In addition, the order of creation of the tire / wheel assembly model by the analysis device, that is, the creation method of the tire / wheel assembly model is not limited to the above method, and contact calculation is performed between the tire model and the rim model, and the rim model Can be embedded in the wheel model. Here, FIG. 18 is a schematic diagram showing another example of a method for creating a tire / wheel assembly model. As shown in FIG. 18, the analysis device creates a two-dimensional model 191 in the meridional section of the tire model and a two-dimensional model 192 in the meridional section of the rim model, and contacts the two-dimensional model 191 and the two-dimensional model 192. Perform the calculation. Thereby, the analysis apparatus creates a model 190 in which the two-dimensional model 191 and the two-dimensional model 192 are in contact with each other. Thereafter, the analysis apparatus develops the model 190 three-dimensionally around the rotation axis and creates a three-dimensional model 193. The model 193 is a model in which a three-dimensional tire model and a three-dimensional rim model are in contact with each other. Thereafter, the analysis apparatus creates a wheel model 194 and embeds the rim model of the model 193 in the wheel model 194 to create a tire / wheel assembly model 196 in which the model 193 and the wheel model 194 are integrated. .

  As described above, the analysis device can reduce the load of calculation, as described above, by performing the contact calculation between the tire model and the wheel model in a two-dimensional model and then expanding in three dimensions. A tire / wheel assembly model can be created with high accuracy. In addition, since the contact calculation can be executed with a two-dimensional model, the calculation amount of the contact calculation can be reduced.

[Evaluation example]
Next, various wheel models are prepared as wheel models, and a tire / wheel assembly model is created using each wheel model and tire model, and a tire / wheel assembly is created using the rim model of this embodiment. Comparison with the case of creating a three-dimensional model. Here, FIG. 19 is a perspective view showing another example of the wheel model, and FIG. 20 is a cross-sectional view showing a meridional section model of a rim portion of the wheel model shown in FIG. 21 is a perspective view showing another example of the wheel model, and FIG. 22 is a cross-sectional view showing a meridional section model of a rim portion of the wheel model shown in FIG. FIG. 23 is a perspective view showing another example of the wheel model, and FIG. 24 is a cross-sectional view showing a meridional section model of a rim portion of the wheel model shown in FIG.

  The wheel model 202 shown in FIGS. 19 and 20 is a model that accurately reproduces the contact portion with the tire, and the shape of the meridional section is the meridional section model 202a. The wheel model 202 is assumed to be a model 1 wheel model in this evaluation example. The wheel model 202 has 252558 elements. The wheel model 204 shown in FIG. 21 and FIG. 22 is a model in which the shape of the contact portion with the tire is asymmetrical left and right, and the meridional section shape is the meridional section model 204a. In this evaluation example, the wheel model 204 is a model 2 wheel model. The wheel model 204 has 32976 elements, and is configured with larger elements than the wheel model 202. The wheel model 206 shown in FIGS. 23 and 24 is a model in which the shape of the contact portion with the tire is asymmetrical, and the meridional cross-sectional shape is the meridian cross-sectional model 206a. In the present evaluation example, the wheel model 206 is a model 3 wheel model. The wheel model 206 has a number of elements of the wheel model of 7201 and is configured with elements larger than the wheel model 204.

  In this evaluation example, for each of model 1, model 2, and model 3, a tire / wheel assembly is created when it is incorporated into a tire model without using a rim model, and the inflation profile, rim shape, and fitting calculation are created. The time (time required for contact calculation) was evaluated. The fitting calculation time was set to 100 as the time required for the contact calculation of the tire / wheel assembly using the model 1. Further, as a method for creating the tire / wheel assembly of the present embodiment, a tire / wheel assembly was created using the model 2 and the rim model, and the evaluation was performed in the same manner. As the tire model, a similar model having 116688 elements was used. As the rim model, a rim model having 3600 elements was used. The evaluation results are shown in Table 1 below.

  As shown in Table 1, by using the rim model, the rim shape and the inflation profile can be accurately reproduced even when the model 2 in which the shape of the contact portion with the tire is asymmetrical is used. That is, it is possible to calculate the inflation profile and the rim shape similar to the case where the model 1 that accurately reproduces the wheel model is used. Further, the calculation time can be drastically reduced as compared with the case where the model 1 is used.

  As described above, a tire / wheel assembly model creation method, a tire / wheel assembly model creation computer program, a tire / wheel assembly simulation method, and a tire / wheel assembly model creation apparatus according to the present invention are described. Is useful for reducing the time for creating a model for analysis.

DESCRIPTION OF SYMBOLS 1 Tire 10 Tire / wheel assembly 12 Wheel 14 Rim surface 50 Analyzing device 51 Input / output device 52 Processing unit 52a Model creation unit 52b Contact calculation unit 52c Embedding processing unit 52d Analysis unit 53 Input unit 54 Storage unit 55 Display unit 100 Tire Wheel assembly model 102 Tire model 104 Wheel model 106 Rim model

Claims (16)

A tire model creation step in which a computer divides a tire to be analyzed into a plurality of elements to create a tire model;
A rim model creating step in which the computer divides a portion that contacts the tire into elements to create a rim model;
The computer divides the wheel model to be analyzed into a plurality of elements to create a wheel model, and a wheel model creation step;
Performing a contact calculation between the tire model and the rim model, and combining the tire model and the rim model;
Embedding the rim model in the wheel model;
A method for creating a tire / wheel assembly model, comprising:   2. The tire / wheel assembly model creation method according to claim 1, wherein in the embedding step, the rim model combined with the tire model is embedded in the wheel model in the combining step.   The tire / wheel assembly model creation method according to claim 1, wherein, in the combining step, the rim model embedded in the wheel model is combined with the tire model in the embedding step.   In the rim model creation step, an average dimension of an element constituting a contact portion, which is a portion that is in contact with or possibly in contact with the tire model, is calculated based on an average dimension of an element in a region corresponding to the contact portion of the wheel model. The method for creating a tire / wheel assembly model according to any one of claims 1 to 3, wherein the tire / wheel assembly model is also made smaller.   The rim model creating step is characterized in that an average dimension of an element constituting a contact portion that is a portion that is in contact with or possibly in contact with the tire model is made smaller than an average dimension of elements other than the contact portion. The method for creating a tire / wheel assembly model according to any one of claims 1 to 4.   6. The rim model creation step creates a model composed of only a contact portion that is a portion that is in contact with or possibly in contact with the tire model, as the rim model. A method for creating a tire / wheel assembly model according to Item 1.   The tire / wheel assembly model according to any one of claims 1 to 6, wherein in the rim model creation step, an end portion of the rim model on a meridional section is folded back inward in a tire radial direction. How to create   8. The contact step according to claim 1, wherein contact calculation is performed at a setting in which a static friction coefficient between the rim model and the tire model is larger than a dynamic friction coefficient between the rim model and the tire model. The method for creating the tire / wheel assembly model according to Item.   9. The tire / wheel assembly model according to claim 8, wherein the coupling step performs contact calculation using the dynamic friction coefficient as a value that changes in accordance with a relative sliding speed of the tire model and the rim model. How to create   10. The coupling step is set so that the tire model does not slip with respect to the rim model after contact calculation is performed and the tire model is fitted to the rim model. A method for creating a tire / wheel assembly model according to any one of the above.   11. The wheel model according to claim 1, wherein a mass, a center of gravity position, a moment of inertia, and an eigenvalue are equal to a mass, a center of gravity position, a moment of inertia, and an eigenvalue of a wheel model in which a rim model is embedded. The method for creating the tire / wheel assembly model according to Item. A tire cavity creating step for modeling a region surrounded by a tire and a wheel as a tire cavity;
The tire / wheel assembly model creation method according to claim 1, further comprising a cavity coupling step of coupling the tire cavity with either a tire model or a rim model. In the tire model creation step, the tire model is created as a two-dimensional tire model having a meridional section, and after the process of the combining step is completed, the two-dimensional tire model is developed in a circumferential direction to obtain a three-dimensional tire model. Create
In the rim model creation step, the rim model is created as a two-dimensional rim model having a meridional section, and after the processing of the coupling step is completed, the two-dimensional rim model is developed in a circumferential direction to create a three-dimensional rim model. The method for creating a tire and wheel assembly model according to any one of claims 1 to 12.   A computer program for creating a tire / wheel assembly model, which causes a computer to execute the method for creating a tire / wheel assembly model according to any one of claims 1 to 13.   A simulation of a tire / wheel assembly in which a computer performs an analysis using the tire / wheel assembly model created by the tire / wheel assembly model creation method according to claim 1. Method. Divide the tire to be analyzed into multiple elements, create a tire model, divide the part that contacts the tire into elements, create a rim model, divide the wheel model to be analyzed into multiple elements A model creation section for creating a wheel model;
Contact calculation between the tire model and the rim model is performed, and a contact calculation unit that combines the tire model and the rim model;
An embedding processing unit for embedding the rim model in the wheel model;
An apparatus for creating a tire / wheel assembly model, comprising:

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