JP2007237752A - Tire performance predicting method, tire designing method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the prediction of tire performances such as noise performance of a tire with a pattern formed of a plurality of land parts. <P>SOLUTION: Various kinds of conditions are determined by creating as an acoustic tube model a space formed between a tire model and road surface by a FEM (finite element method) (Steps 100-110). Then, acoustic characteristic analysis is executed by a boundary element method (Step 112) to evaluate an analysis result in an observation point (Steps 114, 116). By simulating the acoustic characteristic through the utilization of the boundary element method, the noise radiation characteristic is essentially contained by a tread pattern of a tire can be practically and easily evaluated. As a result, a low noise tire can be easily provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tire performance prediction method, a tire design method, and a program, and more particularly to a tire performance prediction method, a tire design method, and a program for predicting noise performance as tire performance.

  The analysis of tire behavior is based on the results of measuring the tires actually designed and manufactured and using the results of performance tests obtained by mounting them on automobiles. Can now be realized. As a main method for analyzing the tire behavior by simulation, a numerical analysis method such as a finite element method (FEM) is mainly used. FEM is a technique of modeling a structure with a finite number of elements and analyzing the behavior of the structure using a computer. The structure is divided into a finite number of elements from its features (mesh division or element division). It is analyzed.

By the way, it is possible to predict the tire performance by analyzing the tire behavior using FEM, and the tire performance includes tire performance such as steering performance, wear performance, stress strain performance, and tire pattern noise. Etc. are known. In particular, in order to obtain tire noise performance, the entire tire is numerically modeled with a finite element model, and vibration modes are identified by FEM and the noise around the tire for each mode frequency is simulated. Examples of techniques for efficiently predicting tire noise include a technique for predicting tire noise performance by converting friction energy generated between a tire and a road surface into sound (see, for example, Patent Document 1), a tire A technique for predicting the noise performance of a tire caused by the pitch arrangement of the above (for example, see Patent Document 2) is known.
JP 2002-90264 A JP 2003-136926 A

  However, the tire model has a huge calculation load for analysis, such as a large scale and a calculation time of several days. In addition, it is assumed that the above-described technology is used for structural design of a tire, and it is difficult to apply the design to a design such as a tire tread pattern.

  In consideration of the above facts, the present invention provides a tire performance prediction method, a tire design method, and a program capable of easily executing a tire performance prediction such as a noise performance of a tire having a pattern composed of a plurality of land portions. With the goal.

  In order to achieve the above object, the present inventors have made various studies, and as a result, the “Boundary Element Method” (hereinafter referred to as “BEM”) used in different fields such as acoustic simulation is referred to as a tire. Focusing on its application to special fields, it has been studied and established as a tire performance prediction method that specifically considers noise. Specifically, the tire performance prediction method of the invention of claim 1 defines (a) a tire model that can be deformed with respect to a tire having a pattern including at least an internal structure and comprising a plurality of land portions. In order to express the space formed by the tread surface and the tire contact surface in the tire tread area at the time of tire contact using the tire model, the tread surface shape and the tire contact surface in the tire tread at the time of tire contact are formed as a film. Defining a sound tube model regarded as an element, defining a sound source model having a spectrum of a plurality of sounds, and determining a positional relationship and a direction of giving the sound source model to the sound tube model; (b) generated in the sound source model Acoustically analyzing the reflection of the sound in the acoustic tube model by a boundary element method; (c) for sound evaluation Determine the position of the stations, including the step, of predicting the noise performance of the tire by determining the spectral variation of the source model at the observation point.

  In step (a) of the present invention, a tire model capable of giving a deformation to a tire having a pattern including at least an internal structure and including a plurality of land portions is determined. Along with this, in order to express the space formed by the tread surface and the tire contact surface in the tire tread area at the time of tire contact using the tire model, the tread surface shape and the tire contact surface in the tire tread at the time of tire contact The acoustic tube model is defined as a film element. Further, in this step (a), a sound source model having a spectrum of a plurality of sounds is determined, and a positional relationship and an applying direction of the sound source model with respect to the acoustic tube model are determined. Thereby, the space formed by the tire and the tire ground contact surface such as a road surface can be handled as an acoustic tube, and sound can be given to the acoustic tube. The acoustic analysis in the acoustic tube is performed in the next step (b). That is, in step (b), the sound generated by the sound source model is acoustically analyzed by the boundary element method for reflection in the acoustic tube model. Thereby, it is possible to grasp how the sound from the sound source behaves in the acoustic tube. In the next step (c), the position of the observation point for acoustic evaluation is determined, and the noise performance of the tire is predicted by obtaining the spectral variation of the sound source model at the observation point. In this way, acoustic analysis is performed using the boundary element method, and for example, the acoustic characteristics of the space in the tire tread formed by the contact between the tread pattern and the road surface can be easily simulated.

  The invention according to claim 2 is the tire performance prediction method according to claim 1, wherein in step (a), at least one of the position on the tire depression side and the tire kick-out side is set as the sound source model generation position. It is characterized by defining. It is considered that most of the sound generation sources related to the tire are the contact portions between the tire and a tire ground contact surface such as a road surface. For this reason, for example, by determining in step (a) at least one position on the tire stepping side and tire kicking side in the vicinity of the contact portion between the tread pattern and the road surface at the generation position of the sound source model, a more actual use environment It is possible to perform acoustic analysis of tires in accordance with

  A third aspect of the invention is the tire performance prediction method according to the first or second aspect, wherein the step (a) includes a tread surface shape outside the tire tread as the acoustic tube model. To do. When a space formed by a tire and a tire ground contact surface such as a road surface is handled as an acoustic tube, reflection of sound is predicted by articles around the acoustic tube. In the case of a tire, a tread outside the tire tread is mainly considered. Therefore, by including the tread surface shape outside the tire tread as the acoustic tube model, acoustic analysis can be performed for the entire tire.

  The invention according to claim 4 is the tire performance prediction method according to any one of claims 1 to 3, wherein a sound pressure amplitude value or a particle velocity amplitude value is defined in the sound source model. . The sound source model is preferably set to a sound pressure amplitude value or a particle velocity amplitude value that facilitates sound handling.

  A fifth aspect of the present invention is the tire performance prediction method according to any one of the first to third aspects, wherein the sound source model includes a pressure amplitude value or a particle velocity amplitude in at least a part of a pattern including a land portion. It is characterized by a value. As mentioned above, most of the sound sources related to tires are considered to be the contact part between the tire and the tire ground contact surface such as the road surface, so that the sound source model is not set at a new position, but from the land part. By setting the pressure amplitude value or the particle velocity amplitude value in at least a part of the pattern, the sound source model can be easily set.

  A sixth aspect of the present invention is the tire performance prediction method according to any one of the first to fifth aspects, wherein in the step (b), propagation of a sound of a predetermined fluid that fills the acoustic tube model is performed. It is characterized in that acoustic analysis is performed after determining the physical property state (sound speed, density, attenuation) related to. Although sound mediates propagation, the behavior changes depending on physical properties such as a physical quantity caused by the material and a physical quantity for specifying the propagation itself. For this reason, a physical property state (for example, a physical property state represented by any one physical quantity such as sound velocity, density, attenuation, etc.) related to the propagation of the sound of a predetermined fluid that fills the acoustic tube model in step (b) is used. By performing acoustic analysis after the determination, acoustic analysis in an actual acoustic environment can be easily performed.

  A seventh aspect of the invention is the tire performance prediction method according to any one of the first to sixth aspects, wherein the prediction result of the noise performance of the tire in the step (c) satisfies a predetermined required value. The method further includes the step (d) of repeating the steps (b) and (c) after correcting the tire model and the acoustic tube model in the step (a). When the acoustic analysis result is obtained, it is possible to evaluate whether or not the acoustic analysis result can accept the expected value predicted in advance. If this required value is not acceptable, it is preferable to modify the tire model to satisfy the required value. Therefore, after correcting the tire model and the acoustic tube model in step (a) until the predicted result of the noise performance of the tire in step (c) satisfies a predetermined required value, steps (b) and (c) are repeated. Step (d) is further included. As a result, the tire model and the acoustic tube model can be corrected so as to satisfy a predetermined required value.

  Next, the tire can be designed more efficiently by using the tire performance prediction method described above. Specifically, in the tire designing method of the invention of claim 8, in order to design a tire by a computer, (a) a tire having a pattern including at least an internal structure and including a plurality of land portions may be deformed. A tread surface in the tire tread at the time of tire contact to define a possible tire model and to express a space formed by the tread surface and the tire contact surface in the tire tread area at the time of tire contact using the tire model (B) defining an acoustic tube model in which the shape and the tire contact surface are regarded as membrane elements, defining a sound source model having a spectrum of a plurality of sounds, and determining a positional relationship and an applying direction of the sound source model with respect to the acoustic tube model; ) For the sound generated by the sound source model, reflection in the acoustic tube model is acoustically solved by the boundary element method. (C) determining the position of the observation point for acoustic evaluation, and predicting the noise performance of the tire by determining the spectral variation of the sound source model at the observation point; (d) in step (c) (E) repeating the steps (b) and (c) after correcting the tire model and the acoustic tube model in the step (a) until the prediction result of the noise performance of the tire satisfies a predetermined required value; d) designing a tire based on a tire model satisfying the required value.

  When the tire performance is predicted by a computer, the tire performance can be predicted easily and simply by causing the computer to execute the following program. Specifically, the invention of claim 9 defines (a) a tire model that can be deformed with respect to a tire having a pattern including at least an internal structure and comprising a plurality of land portions, and uses the tire model. In order to express the space formed by the tread surface and the tire contact surface in the tire tread area at the time of tire contact, the acoustic tube in which the tread surface shape in the tire tread surface and the tire contact surface at the time of tire contact is regarded as a membrane element Defining a sound source model having a plurality of sound spectrums and determining a positional relationship and a direction of the sound source model with respect to the sound tube model; and (b) the sound tube model for sound generated by the sound source model. (C) determining the position of the observation point for acoustic evaluation, Predicting the noise performance of the tire by determining the spectral variation of the source model at observation point, characterized in that it comprises a.

  As described above, according to the present invention, a space formed by a tire and a tire ground contact surface such as a road surface is treated as an acoustic tube and sound is given to the acoustic tube, and acoustic analysis in the acoustic tube is performed by a boundary element method. Since it implements, there exists an effect that the acoustic characteristic of the space in the tire tread formed by contact with a tread pattern and a road surface can be easily estimated about tire performance, especially acoustic performance.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, the present invention is applied to performance prediction of a pneumatic tire.

  FIG. 1 shows an outline of a personal computer for performing tire performance prediction in consideration of tire noise performance of the present invention. The personal computer includes a keyboard 10 for inputting data and the like, a computer main body 12 that predicts tire performance according to a pre-stored processing program, and a CRT 14 that displays calculation results of the computer main body 12 and the like.

  The computer main body 12 includes a flexible disk unit (FDU) into which a flexible disk (FD) as a recording medium can be inserted and removed. Note that processing routines and the like described later can be read from and written to the flexible disk FD using the FDU. Therefore, a processing routine to be described later may be recorded in the FD in advance and the processing program recorded in the FD may be executed via the FDU. Further, a mass storage device (not shown) such as a hard disk device is connected to the computer main body 12, and the processing program recorded on the FD is stored (installed) in the mass storage device (not shown) and executed. Also good. Recording media include optical discs such as CD and DVD, and magneto-optical discs such as MD and MO. When these are used, instead of or in addition to the FDU, a CD-ROM device, a CD-RAM device, a DVD- A ROM device, DVD-RAM device, MD device, MO device, or the like may be used.

  First, an outline of processing for predicting tire noise performance for a flat road surface as a tire ground contact surface in contact with the tire will be described in the tire performance prediction evaluation. In addition, this invention is not limited to a flat road surface, A bad road may be sufficient and it is good also as a fluid as what a tire contacts first. This fluid includes a field including a liquid such as water, a fluid having shear stress such as snow, and soil.

  FIG. 2 shows a processing routine of the tire performance prediction evaluation program. In this process, the tire performance is predicted, and the tire performance is evaluated from the prediction result. The actual acoustic characteristics are measured, and a predicted value of tire noise performance is obtained by numerical calculation using the measured acoustic characteristics. In numerical computation, FEM modeling, road surfaces and tires are coupled, a membrane tube acoustic tube model is created, and acoustic properties are obtained for the acoustic tube model by a boundary element method to obtain a predicted value.

  Specifically, in step 100 of FIG. 2, a design plan (change of tire shape, structure, material, pattern, etc.) of the tire to be evaluated is determined. In this step 100, a tire including a pattern including at least an internal structure and including a plurality of land portions is employed, and in particular, a design proposal capable of expressing at least the pattern, that is, the surface shape of the tread is employed.

  In the next step 102, a tire model is created in order to drop the tire design proposal into a numerical analysis model. In the present embodiment, the tire model is created by using a finite element method (FEM) as a numerical analysis method. Accordingly, the tire model created in step 102 is divided into a plurality of elements by element division corresponding to the finite element method (FEM), for example, mesh division, and the tire is created based on a numerical / analytical method. This is the numerical value of the input data format for the program. This element division refers to dividing an object such as a tire and a road surface into several small (finite) small parts. After calculating every small part and calculating all the small parts, the whole response can be obtained by adding all the small parts. Note that a difference method or a finite volume method may be used as a numerical analysis method.

  In the creation of the tire model in step 102, a pattern is modeled after a tire cross-section model is created. Specifically, first, a tire radial section model, that is, tire section data is created. The tire cross-section data is obtained by measuring the tire outer shape with a laser shape measuring instrument or the like. In the present embodiment, the structure inside the tire is not particularly necessary. However, when performing a detailed analysis including the structure inside the tire, accurate data is collected from the design drawing and actual tire cross-section data. May be. Here, a case where the entire tire is modeled will be described. For example, rubber in the tire cross section, reinforcing material (belt, ply, etc., a bundle of reinforcing cords made of iron / organic fibers, etc., bundled in a sheet shape) are modeled according to the modeling method of the finite element method, respectively ( (See FIG. 3A). Next, the tire cross-section data (tire radial cross-section model), which is two-dimensional data, is developed by one round in the circumferential direction to create a three-dimensional (3D) model of the tire (see FIGS. 3B and 3C). ). Next, the pattern is modeled. This pattern is modeled by “modeling part or all of the pattern separately and pasting it as a tread part on the tire model”, “considering rib and lug components when developing tire cross-section data in the circumferential direction. To create a pattern ". For the above modeling, tire modeling by FEM can be used.

  After creating the tire model as described above, the process proceeds to step 104 to create an acoustic tube model. This acoustic tube model is to model a tubular space filled with gas or fluid outside the tire, which is formed when the tire contacts the tire contact surface which is the road surface. In the creation of the acoustic tube model, a part (or all) of the tire and the contact surface are divided and modeled. More specifically, the surface shape of the tread is modeled by a membrane element among the elements used in the finite element method as a space formed by the tire grounding on the tire ground contact surface that is a road surface. In addition, the tire ground contact surface, which is a road surface, is modeled as a membrane element simply as a membrane. In this case, since it is not necessary to model other than the surface shape of the groove (tire pattern groove) of the tread, the film model is a combination of a plurality of acoustic tubes. FIG. 4 shows a perspective view of the acoustic tube model. In FIG. 4, only the space formed by the tire being in contact with the tire contact surface, which is the road surface, is modeled. However, the present invention is not limited to this, and the surface shape of the tire tread is not limited thereto. These may all be treated as a film and modeled.

  When the creation of the acoustic tube model is completed in this way, a sound source model is created in the next step 106. The sound source model is a model of a spectrum or spectrum distribution of sound that can be generated in an actual tire, and is created as a kind of energy model. In the next step 108, input values of the created sound source model are defined. Since the sound source model is a spectrum or spectrum distribution of sound that can be generated in an actual tire, these values are defined. For example, as an example of the input value, a sound pressure amplitude value (pressure amplitude value) or a particle velocity amplitude value is defined for each frequency. Note that these values may be values obtained by directly measuring sound generated from an actual speaker (speaker), or may be a spectrum created on an arbitrary frequency axis.

  In this step 108, the position of the sound source model (sound generation position) can be determined. The sound generated in an actual tire includes when the tire contacts an external article, for example, when it contacts a road surface or fluid. In addition, a resonance sound generated when gas contacts or passes through the tire, such as a wind noise, is also assumed. In this case, particularly as the generated sound, it is assumed that the influence of the contact portion between the tire and the tire ground contact surface such as the road surface is large. For this reason, for example, by determining the generation position of the sound source model at least one position on the tire stepping side and the tire kicking side in the vicinity of the contact portion between the tread pattern and the road surface, the tire is more suitable for the actual use environment. Acoustic analysis can be performed. Note that the propagation direction may be further determined after the generation position of the sound source model is determined.

  In the next step 110, boundary conditions are set. First, boundary conditions regarding inflow / outflow of gas or fluid are given to the acoustic tube model. Here, since the analysis is performed in a steady state, an acoustic tube model in which sound propagates in a state where the tire model is stationary is considered. That is, a physical property state representing the behavior of gas or fluid in the acoustic tube model is set. As the physical property state, for example, there is a physical property of a medium which is a gas such as air of sound propagating in the acoustic tube model or a fluid such as water. There are parameters representing the speed of sound, density, and attenuation that propagate as physical properties.

  In addition, some sound that propagates in the acoustic tube model is reflected by the boundary of the acoustic tube model. For this reason, you may define the parameter which determines the reflectance of the sound resulting from a tire material or a road surface state for every site | part of an acoustic tube model. For example, in step 104 above, the road surface is treated as a membrane as an acoustic tube model, but the road surface model is created for the road surface, and the boundary condition is set by inputting the road surface state relating to the sound behavior together with this. May be. Further, the boundary condition may be set by inputting the tire material on the tire model side of the acoustic tube model.

  Since part of the tire model comes in contact with the road surface, the acoustic tube model including at least part of the surface shape of the tread in the tire model is given analytical boundary conditions to simulate the sound behavior. Can do. For example, with respect to the sound source model created in step 106 and defined as input values, individual pressure amplitude values are applied to some or all elements of the tread pattern model as boundary conditions in step 108 described above, not as a specific sound source model. Alternatively, the particle velocity amplitude value may be defined.

  In the next step 112, numerical calculation by the boundary element method is performed based on the numerical model created or set up to step 110. In this step 112, an acoustic characteristic analysis is performed in which the sound reflected and propagated in the acoustic tube model is calculated by the boundary element method. In order to evaluate the result of the acoustic characteristic analysis by the boundary element method in step 112, observation points are set in the next step 114. This observation point is set at a position different from the acoustic tube model, the tire model, the tire ground contact surface (road surface), and the sound source model. FIG. 5 shows an example of the positional relationship among the observation point 56, the acoustic tube model 50, the tire model 52, the tire ground contact surface (road surface) 58, and the sound source model 54.

  In the next step 116, the physical quantity of the acoustic characteristic analysis result at the observation point 56 set in step 114 is output as a result, and the physical quantity is evaluated. Examples of the physical quantity of the acoustic characteristic analysis result include a sound spectrum and spectrum distribution at the observation point 56, and specific values include a sound pressure amplitude value and a particle velocity amplitude value for each frequency. The evaluation of the physical quantity is to determine whether or not the sound spectrum or spectrum distribution at the observation point 56 is a predetermined requested quantity of physical quantity (or a predetermined allowable range less than that) acceptable as noise performance. Can be executed. When the sound spectrum (distribution) at the observation point 56 is a physical quantity equal to or less than the required value, it is evaluated that the predicted performance is good, and when the sound spectrum exceeds the required value, the predicted performance is evaluated as poor.

  In addition, when outputting the physical quantity of the acoustic characteristic analysis result in the observation point 56 as a result in step 116, it can be displayed as distribution of each physical quantity. Examples of the display include a color contour diagram, a uniform distribution diagram, a vector diagram, and a deformed state. In this case, a value input from the keyboard or the like by the operator based on the display may be used as the evaluation value. In other words, the evaluation of the prediction result uses the output value of the prediction result and the distribution of the output value, and numerically expresses how much the predetermined allowable value and the allowable characteristic match each output value and the distribution of the output value. Thus, an evaluation value can be determined.

  Next, in step 118, it is determined from the evaluation of the prediction result whether the prediction performance is good. The determination in step 118 may be made by inputting from a keyboard, or may be determined from the evaluation value.

  As a result of the evaluation of the predicted performance, if the target performance is insufficient, the result is negative in step 118, the design plan is changed (corrected) in step 120, the process returns to step 102, and the processing so far is repeated. On the other hand, when the performance is sufficient, the result is affirmative in step 118, and in step 122, the surface shape of the tread of the acoustic tube model created based on the tire model in step 102 is determined as the pattern design. In the next step 124, a tire of the design plan based on the pattern design determined in step 122 is manufactured, and performance evaluation is performed on the manufactured tire in the next step 126. If the performance evaluation result is unsatisfactory, the result in Step 128 is negative and the process returns to Step 120. On the other hand, when the result of the performance evaluation in step 126 is satisfactory performance (good performance), the result in step 128 is affirmed, and in the next step 130, the design plan modified in step 100 or step 120 is evaluated as good. Adopt as performance, and end this routine. The adoption of the design plan in step 130 outputs (displays or prints) that the design plan has good performance, and stores the data of the design plan.

  Thus, in this embodiment, the boundary element method is used for acoustic analysis, and in particular, the acoustic characteristics of the tire tread space formed by the contact between the tread pattern and the road surface are simulated, and the tire tread is practically and simply used. The noise radiation characteristic inherent in the pattern can be evaluated, and a low-noise tire can be easily provided.

  In the present embodiment, since the reflection of sound is calculated by the boundary element method, since the calculation is performed in the frequency space, acoustic analysis can be performed in a shorter time than FEM. Also, in the experiment of the sound generated by the tire, all sounds (indirect sound, direct sound, among them, pattern noise, air column resonance sound, cavity resonance sound, etc.) are observed in a mixed manner. It was difficult to separate the contribution of whether the sound affects the noise performance of the tire. However, in this embodiment, the sensitivity of the pattern to the air column resonance sound can be calculated unambiguously, so that in the pattern development such as the tread pattern of the tire, each pattern can be separated in the pattern design. Can contribute.

  Next, embodiments of the present invention will be described in detail. Tire standards are determined by industry standards that are valid in the region where the tire is produced or used. For example, in the United States, "The Tire and Rim Association Inc. Year Book", in Europe "The European Tire and Rim Technical Organization Standards Manual", and in Japan, the Japan Automobile Tire Association "JATMA Year Book". ing.

  After modeling for performance prediction based on this tire, performance prediction of the tire model was performed, and the prediction results and actual measurement results were shown together.

  The tire modeled and prototyped as this example has a tire size of 195 / 65R15.

  FIG. 6 shows a measuring device 60 that measures tire acoustic characteristics of an actually manufactured tire. The measuring device 60 includes an iron jig 66 for attaching a tire 68, and a speaker 62 as a sound source is installed on one side of the tire 68. In addition, a microphone 64 for collecting sound is attached to the jig 66. These speaker 62 and microphone 64 are connected to the controller 70. The controller 70 outputs a signal for generating sound from the speaker 62 and inputs an audio signal picked up by the microphone 64 to calculate an acoustic characteristic. In this measuring device 60, first, the tire 68 is pressed against the iron jig 66 to generate white noise from the speaker 62. In this state, the sound pressure in the groove on the tread surface is measured by the microphone 64 provided on the jig 66.

  FIG. 7 shows the acoustic characteristics obtained by the simulation shown in FIG. 2 for the acoustic characteristics of the groove on the tread surface measured by the measuring device of FIG. 6 and the tire model (acoustic tube model) created from the tire design plan of the same shape. The frequency characteristics with the prediction results of characteristic analysis are presented. As can be seen from FIG. 7, the acoustic characteristics of the tire pattern could be simulated with higher accuracy.

  Further, in Table 1 below, the calculation result of the acoustic characteristic analysis using only the FEM is used as a comparative example, and the calculation result of the acoustic characteristic analysis using the BEM according to the above embodiment is used as an example. The result of index notation was shown with this comparative example as 100.

  As understood from Table 1, a good result was obtained that the acoustic characteristic analysis according to the present embodiment can be processed in a short time. Therefore, this performance prediction is effective for the performance prediction of the design plan, and it is possible to replace a part of the tire development cycle of design / manufacturing / performance evaluation with numerical analysis. It is understood that the efficiency of tire development can be improved by utilizing this.

It is the schematic of the personal computer for enforcing the tire performance prediction method concerning embodiment of this invention. It is a flowchart which shows the flow of the process of the program concerning this Embodiment and predicting tire performance in tire performance evaluation. A tire model is shown, (A) is a tire radial direction section model (B), a tire three-dimensional model is shown, (C) is a perspective view showing an image which modeled a pattern. It is a perspective view which shows an acoustic tube model. It is explanatory drawing about the positional relationship of an observation point. It is a diagram which shows the measuring apparatus which measures the acoustic characteristic of the actually manufactured tire in an Example. It is a characteristic view which shows the prediction result of the acoustic characteristic analysis of the acoustic characteristic of the groove part in a tread surface actually measured with the measuring apparatus, and the prediction result obtained by simulation of embodiment.

Explanation of symbols

10 Keyboard 12 Computer body 14 CRT
FD flexible disk (recording medium)

Claims (9)

A tire performance prediction method including the following steps.
(A) A tire model capable of deforming a tire including at least an internal structure and having a pattern composed of a plurality of land portions is determined, and a tread in a tire tread area at the time of tire contact is determined using the tire model. In order to express the space formed by the surface and the tire contact surface, a tread surface shape in the tire tread surface at the time of tire contact and an acoustic tube model in which the tire contact surface is regarded as a membrane element are defined, and a spectrum of multiple sounds is provided. Defining a sound source model and determining a positional relationship and a direction of the sound source model with respect to the acoustic tube model;
(B) A step of acoustically analyzing reflection in the acoustic tube model for the sound generated by the sound source model by a boundary element method.
(C) The step of determining the position of the observation point for acoustic evaluation and predicting the noise performance of the tire by obtaining the spectral variation of the sound source model at the observation point.   2. The tire performance prediction method according to claim 1, wherein in the step (a), at least one position on a tire depression side and a tire kick-out side is determined as a generation position of a sound source model.   The tire performance prediction method according to claim 1 or 2, wherein in the step (a), a tread surface shape outside the tire tread is included as the acoustic tube model.   The tire performance prediction method according to any one of claims 1 to 3, wherein a sound pressure amplitude value or a particle velocity amplitude value is determined in the sound source model.   The tire performance according to any one of claims 1 to 3, wherein the sound source model is obtained by determining a pressure amplitude value or a particle velocity amplitude value in at least a part of a pattern composed of a land portion. Prediction method.   6. The acoustic analysis is performed in the step (b), after a physical property state related to propagation of sound of a predetermined fluid that fills the acoustic tube model is determined. The tire performance prediction method according to item.   Steps (b) and (c) are repeated after correcting the tire model and the acoustic tube model in Step (a) until the predicted result of the noise performance of the tire in Step (c) satisfies a predetermined required value ( The tire performance prediction method according to any one of claims 1 to 6, further comprising d). A tire designing method comprising the following steps for designing a tire by a computer.
(A) A tire model capable of deforming a tire including at least an internal structure and having a pattern composed of a plurality of land portions is determined, and a tread in a tire tread area at the time of tire contact is determined using the tire model. In order to express the space formed by the surface and the tire contact surface, a tread surface shape in the tire tread surface at the time of tire contact and an acoustic tube model in which the tire contact surface is regarded as a membrane element are defined, and a spectrum of multiple sounds is provided. Defining a sound source model and determining a positional relationship and a direction of the sound source model with respect to the acoustic tube model;
(B) A step of acoustically analyzing reflection in the acoustic tube model for the sound generated by the sound source model by a boundary element method.
(C) The step of determining the position of the observation point for acoustic evaluation and predicting the noise performance of the tire by obtaining the spectral variation of the sound source model at the observation point.
(D) Steps (b) and (c) are performed after correcting the tire model and the acoustic tube model in step (a) until the prediction result of the noise performance of the tire in step (c) satisfies a predetermined required value. Repeat step.
(E) A step of designing a tire based on a tire model that satisfies the required value in step (d). A tire performance prediction program comprising the following steps for predicting tire performance by a computer.
(A) A tire model capable of deforming a tire including at least an internal structure and having a pattern composed of a plurality of land portions is determined, and a tread in a tire tread area at the time of tire contact is determined using the tire model. In order to express the space formed by the surface and the tire contact surface, a tread surface shape in the tire tread surface at the time of tire contact and an acoustic tube model in which the tire contact surface is regarded as a membrane element are defined, and a spectrum of multiple sounds is provided. Defining a sound source model and determining a positional relationship and a direction of the sound source model with respect to the acoustic tube model;
(B) A step of acoustically analyzing reflection in the acoustic tube model by a boundary element method for the sound generated by the sound source model
(C) The step of determining the position of the observation point for acoustic evaluation and predicting the noise performance of the tire by obtaining the spectral variation of the sound source model at the observation point.

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