JP2014121912A - Simulation method for tire, evaluation method for tire characteristic, manufacturing method for tire, and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform analysis of performance of a tire with high precision.SOLUTION: There is provided a simulation method for a tire in which an analyzing device 50 (for example, a computer) analyzes the tire. The analyzing device 50 (for example, the computer) executes a step of analyzing an analysis model for the tire which has parts, constituting the tire, stacked and divided into a finite plurality of elements when a predetermined tensile load and a predetermined three-point bending load are placed thereupon. The predetermined tensile load is, for example, tension assumed to be applied to a belt layer through action of internal pressure of the pneumatic tire, and the predetermined three-point bending load is tension assumed to be applied to the belt layer by a grounding load (push-in load or push-in displacement) acting on the pneumatic tire when the pneumatic tire is grounded.

Description

  The present invention relates to a technique for analyzing a tire using a computer.

  In recent years, a simulation apparatus that creates a tire model that can be analyzed by a computer and performs a simulation has been put into practical use. As such a simulation apparatus, a technique described in Patent Document 1 is known.

JP 2011-219027 A

  FIGS. 16 and 17 are diagrams for explaining a conventional simulation method executed by a simulation apparatus using a model of the entire tire. As shown in FIG. 16, in the simulation (deformation analysis) for measuring the internal pressure growth of the tire, a two-dimensional axisymmetric model is created and the growth amount (growth rate) of the tread center portion P1, shoulder portion P2, etc. ). Further, as shown in FIG. 17, in the simulation (deformation analysis) for measuring the durability of the tire, an overall model of the tire is created and the interlayer strain of the portion P3 corresponding to the belt layer constituting the tire is measured. Etc.

  As shown in FIG. 16 and FIG. 17, in the simulation using the model of the entire tire that can be analyzed by the computer, since the number of elements constituting the entire model of the tire is large, the amount of data related to model creation and simulation is enormous. It becomes. For this reason, there is a problem that not only the burden of increasing the calculation cost required for the tire simulation is high, but also screening is difficult.

  The present invention has been made in view of the above, and includes a tire simulation method, a tire characteristic evaluation method, a tire manufacturing method, and a pneumatic tire that can realize simple and accurate tire performance analysis. It is to provide.

  In order to solve the above-described problems and achieve the object, the present invention provides a tire simulation method in which a computer analyzes a tire, and the computer stacks a plurality of parts constituting the tire and is finite. And performing an analysis when a predetermined tensile load and a predetermined three-point bending load are applied to the tire analysis model divided into a plurality of elements.

  The present invention is also a tire characteristic evaluation method for evaluating tire characteristics based on a tire analysis result executed by a computer, wherein the computer stacks parts constituting a belt layer of the tire. A step of performing analysis when a predetermined tensile load and a predetermined three-point bending load are applied to the tire analysis model divided into a finite number of elements, and an interlayer of the belt layer obtained by the analysis And a step of outputting distortion data.

  Further, the present invention provides a tire manufacturing method for manufacturing a tire, wherein the tire analysis model is obtained by stacking parts constituting a belt layer of the tire on a computer and dividing the tire into finite and plural elements. And a step of executing an analysis when a predetermined tensile load and a predetermined three-point bending load are applied, and a design method of the belt layer is determined based on interlayer strain data of the belt layer obtained by the analysis. And generating a green tire including a belt layer generated according to the design method.

  Further, the pneumatic tire according to the present invention has a computer with a predetermined tensile load and an analysis model for the tire that is divided into a finite number of elements by laminating parts constituting the belt layer of the tire on a computer. A step of executing an analysis when a predetermined three-point bending load is applied; a step of determining a design method of the belt layer based on interlayer strain data of the belt layer obtained by the analysis; and the design method And a step of producing a green tire including a belt layer produced according to the above.

FIG. 1 is a sectional view in the meridian direction of a pneumatic tire. FIG. 2 is a block diagram illustrating a functional configuration of an analysis apparatus that executes the tire simulation method according to the present embodiment. FIG. 3 is a diagram illustrating an example of a laminated plate finite element model according to the present embodiment. FIG. 4 is a diagram illustrating an example of a longitudinal side surface of the laminated plate finite element model according to the present embodiment. FIG. 5 is a flowchart showing a processing procedure of the tire simulation method according to the present embodiment. FIG. 6 is a flowchart showing a processing procedure of the tire simulation method according to the present embodiment. FIG. 7 is a diagram illustrating a data example of a tire growth amount (rate) by a tire internal pressure test. FIG. 8 is a diagram showing an image when a tensile load is applied to the laminated plate finite element analysis model. FIG. 9 is a diagram illustrating an example of an analysis result when a tensile load is applied to the laminated plate finite element model. FIG. 10 is a diagram showing an image when a tensile load and a three-point bending load are applied to the laminated plate finite element model. FIG. 11 is a diagram comparing the result of deformation analysis of the laminated plate finite element model M3 corresponding to the belt layer of the five-belt structure and the experimental result of the pneumatic tire having the belt layer of the five-belt structure. FIG. 12 is a diagram showing the correlation between the results of the pneumatic tire running experiment and the analysis result of the interlayer strain of the belt layer obtained as a result of the deformation analysis of the laminated plate finite element model for each 0 degree belt arrangement position. is there. FIG. 13 is a diagram comparing the analysis result by the tensile load and the three-point bending load according to the present embodiment and the analysis result by the conventional three-point bending. FIG. 14 is a view showing a modified example of the laminate finite element model by the tensile load and the three-point bending load according to the present embodiment. FIG. 15 is a diagram showing a modified example of the laminated plate finite element model by the conventional three-point bending method. FIG. 16 is a diagram for explaining a conventional simulation method executed by a simulation apparatus using a model of the entire tire. FIG. 17 is a diagram for explaining a conventional simulation method executed by a simulation apparatus using a model of the entire tire.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention, which is a technique disclosed by the present application (hereinafter referred to as embodiments), will be described in detail with reference to the drawings. In addition, this invention is not limited by embodiment described below. Further, technical matters described in the following embodiments include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the technical matters described in the following embodiments can be appropriately combined within the scope deemed necessary for achieving the object of the present invention.

  FIG. 1 is a sectional view in the meridian direction of a pneumatic tire. In the following description, the tire radial direction corresponds to a direction orthogonal to the rotation axis of the pneumatic tire 1, that is, a direction parallel to the r-axis direction of the coordinate system shown in FIG. The inner side in the tire radial direction is the side toward the rotation axis of the pneumatic tire 1 in the tire radial direction. The outer side in the tire radial direction is the side away from the rotation axis in the tire radial direction. Further, the tire circumferential direction refers to the tire circumferential direction with the rotation axis as the central axis, that is, the direction of θ in the coordinate system shown in FIG. Further, the tire width direction corresponds to a direction parallel to the rotation axis of the pneumatic tire 1, that is, a direction parallel to the h-axis direction of the coordinate system shown in FIG. The inner side in the tire width direction is the side toward the tire equator plane (tire equator line) CL shown in FIG. 1 in the tire width direction. The outer side in the tire width direction is the side away from the tire equatorial plane CL shown in FIG. 1 in the tire width direction. The tire equatorial plane CL is a plane that is orthogonal to the rotation axis of the pneumatic tire 1 and passes through the center of the tire width of the pneumatic tire 1. The tire width is the width in the tire width direction between the portions located outside in the tire width direction, that is, the distance between the portions farthest from the tire equatorial plane CL in the tire width direction. The tire equator line is a line on the tire equator plane CL and along the tire circumferential direction (θ) of the pneumatic tire 1. In the present embodiment, the same sign “CL” as that of the tire equator plane is attached to the tire equator line. In the present embodiment, a case will be described in which the pneumatic tire 1 is a heavy duty radial tire mounted on a steer shaft such as a truck or bus for long-distance transportation.

  As shown in FIG. 1, the pneumatic tire 1 includes a pair of bead cores 11, a pair of bead fillers 12, a carcass layer 13, a belt layer 14, a tread rubber 15, and a pair of sidewall rubbers 16. . The pair of bead cores 11 has an annular structure and constitutes the cores of the left and right bead portions. The bead core 11 is configured by bundling a plurality of strands that are steel wires and covered with rubber that is a tire material. The pair of bead fillers 12 includes a lower filler and an upper filler, and is disposed on the tire radial direction outer periphery of the pair of bead cores 11 to reinforce the bead portion. The carcass layer 13 has a single-layer structure and is bridged in a toroidal shape between the left and right bead cores 11 to form a tire skeleton. Further, both end portions of the carcass layer 13 are wound and locked outward in the tire width direction so as to wrap the bead core 11 and the bead filler 12. The belt layer 14 includes a laminated belt 141, a pair of cross belts 142 and 143, a belt 144, and a circumferential reinforcing layer 145, and is disposed on the outer circumference in the tire radial direction of the carcass layer 13.

  Here, the belt 141 is formed by coating a plurality of belt cords made of steel or organic fiber material with a coat rubber and rolling the belt cord, and has a predetermined belt angle (inclination angle of the belt cord in the fiber direction with respect to the tire circumferential direction). Have. Further, the belt 141 is laminated and disposed on the outer side in the tire radial direction of the carcass layer 13.

  The pair of cross belts 142 and 143 are formed by rolling a plurality of belt cords made of steel or organic fiber material with a coating rubber, and having a belt angle of 10 [deg] or more and 30 [deg] or less in absolute value. Have. Further, the pair of cross belts 142 and 143 have belt angles with different signs from each other, and are laminated so that the fiber directions of the belt cords cross each other (cross-ply structure). Here, the cross belt 142 located on the inner side in the tire radial direction is called an inner diameter side cross belt, and the cross belt 143 located on the outer side in the tire radial direction is called an outer diameter side cross belt. Note that three or more cross belts may be laminated (not shown). In addition, the pair of cross belts 142 and 143 are stacked on the outer side in the tire radial direction of the belt 141.

  The belt 144 is formed by rolling a plurality of belt cords made of steel or an organic fiber material with a coating rubber, and has a belt angle of 10 [deg] or more and 45 [deg] or less in absolute value. Further, the belt 144 is disposed so as to be laminated on the outer side in the tire radial direction of the cross belts 142 and 143. In the present embodiment, the belt 144 has the same belt angle (cord angle) as the outer diameter side crossing belt 143, and is disposed in the outermost layer of the belt layer 14. The belt layer 14 may further include a circumferential reinforcing layer between the cross belts or on the inner side in the tire radial direction of the cross belt.

  The circumferential reinforcing layer 145 is made of a steel wire, and is configured by winding at least one wire in a spiral manner while inclining within a range of ± 5 [deg] with respect to the tire circumferential direction. Further, the circumferential reinforcing layer 145 is disposed between the pair of cross belts 142 and 143. Further, the circumferential reinforcing layer 145 is disposed on the inner side in the tire width direction with respect to the left and right edge portions of the pair of cross belts 142 and 143. Specifically, the wire is spirally wound around the outer periphery of the inner diameter side crossing belt 142 to form the circumferential reinforcing layer 145. The circumferential reinforcing layer 145 reinforces the rigidity in the tire circumferential direction, so that the durability performance of the tire is improved.

  The belt layer 14 may have an edge cover (not shown). Generally, the edge cover is formed by rolling a plurality of belt cords made of steel or organic fiber material with a coat rubber, and has a belt angle within a range of ± 5 [deg] with respect to the tire circumferential direction. Further, the edge covers are respectively disposed on the outer sides in the tire radial direction of the left and right edge portions of the outer diameter side cross belt 143 (or the inner diameter side cross belt 142). When these edge covers exhibit a tagging effect, the difference in diameter growth between the center region of the tread portion and the shoulder region is alleviated, and the uneven wear resistance performance of the tire is improved.

  The tread rubber 15 is disposed on the outer periphery in the tire radial direction of the carcass layer 13 and the belt layer 14 to constitute a tread portion 33 of the tire. The pair of sidewall rubbers 16 are respectively arranged on the outer sides in the tire width direction of the carcass layer 13 to constitute left and right sidewall portions. In the present embodiment, the pneumatic tire 1 has a symmetrical structure with the tire equatorial plane CL as the center.

  In addition, as shown in FIG. 1, the pneumatic tire 1 includes a plurality of circumferential main grooves extending in the tire circumferential direction in the tread portion 33, specifically, one circumferential main groove 21 and two The circumferential main groove 22 and two circumferential main grooves 23 are formed. The pneumatic tire 1 of the present embodiment is formed in the order of a circumferential main groove 21, a circumferential main groove 22, and a circumferential main groove 23 from the tire equatorial plane CL toward the outside in the tire width direction. The circumferential main groove 21 is formed on the tire equatorial plane CL. In the tread portion 33, the tread rubber 15 is divided into circumferential main grooves 21, 22, and 23. A plurality of land portions, specifically, two land portions 41, two land portions 42, and two The shape is divided into land portions 43. The two land portions 41 are regions sandwiched between the circumferential main groove 21 and the circumferential main groove 22. The two land portions 42 are regions sandwiched between the circumferential main groove 22 and the circumferential main groove 23, respectively. The two land portions 43 are regions outside the circumferential main groove 23 in the tire width direction. The land portion 43 is an end portion in the tire width direction in a region where the outer end portion in the tire width direction contacts the road surface of the tread portion 33. Here, the tread portion 33 of the pneumatic tire 1 of the present embodiment is symmetrical with respect to the tire equatorial plane CL. Hereinafter, the circumferential main grooves 21, 22, and 23 may be referred to as a center groove 21, an intermediate groove 22, and a shoulder groove 23.

  Next, an analysis apparatus that executes a tire simulation method (deformation analysis method) according to the present embodiment will be described.

  FIG. 2 is a block diagram illustrating a functional configuration of an analysis apparatus that executes the tire simulation method according to the present embodiment. The tire simulation method according to the present embodiment is realized by the analysis device 50 shown in FIG. The analysis device 50 is a computer and includes a processing unit 52 and a storage unit 54 as shown in FIG. The analysis device 50 is electrically connected to the input / output device 51. The input means 53 provided in the input / output device 51, when creating a tire analysis model, which will be described later, and the physical property values of various materials such as rubber constituting the tire to be evaluated, and the boundary necessary for the tire simulation Various conditions such as conditions and load conditions are input to the processing unit 52 and the storage unit 54.

  An input device such as a keyboard and a mouse is applied to the input unit 53. The storage unit 54 stores at least data for modeling the belt layer 14 (see FIG. 1) of the tire to be analyzed, and data for CAD (Computer Aided Design) of the tire to be analyzed and the parts constituting the tire. A computer program for realizing the tire simulation method according to the present embodiment is stored. The storage unit 54 is a non-volatile memory such as a hard disk device, a magneto-optical disk device, or 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). Memory or a combination thereof.

  The computer program may be capable of realizing the tire simulation method according to the present embodiment in combination with a computer program already recorded in a computer or computer system. Here, the “computer system” includes hardware such as an OS (Operating System) and peripheral devices.

  The processing unit 52 includes a model creation unit 52a, a condition setting unit 52b, and an analysis unit 52c.

  The model creation unit 52a creates a laminated plate finite element model obtained by modeling the belt layer 14 (see FIG. 1) of the pneumatic tire 1 to be analyzed as a model used in the tire simulation method according to the present embodiment. This laminated plate finite element model is included in an analysis model for deformation analysis (simulation) executed by an analysis unit 52c described later. Specifically, the model creation unit 52a reads data for modeling each part constituting the belt layer 14 from the storage unit 54, for example. Subsequently, as shown in FIG. 3, the model creation unit 52 a uses the data read from the storage unit 54 to model each part constituting the belt layer 14 (refer to FIG. 1) in order. Then, by dividing into a finite number of elements, a plate-like laminated plate finite element model M3 as shown in FIG. 3 is created. FIG. 3 is a diagram illustrating an example of a laminated plate finite element model according to the present embodiment. In the present embodiment, for example, as shown in FIG. 4, the laminated plate finite element model M3 in which the belt layer 14 is modeled includes five elements, and a 0-degree belt is set in at least one of the five elements. Is done. In the example shown in FIG. 4, the 0 degree belt is disposed in the center. The 0 degree belt is a belt having an inclination angle of 0 degrees [deg] in the fiber direction of the belt cord with respect to the tire circumferential direction. FIG. 4 is a diagram illustrating an example of a longitudinal side surface of the laminated plate finite element model according to the present embodiment. In addition, although the laminated board finite element model M3 in this embodiment demonstrates the example which sets a 0 degree belt to one of five components, it is not necessary to set a 0 degree belt. Moreover, although the laminated board finite element model M3 in this embodiment demonstrates the example which consists of five components, the number of components can be changed suitably according to the member etc. which are analysis object.

  The model creation unit 52a creates a laminated plate finite element model (see FIG. 3) corresponding to the belt layer 14, and then reads CAD data of the pneumatic tire 1 to be analyzed from the storage unit. Then, the model creation unit 52a creates an overall model that models the shape of the annular structure of the pneumatic tire 1 based on the read data, and creates a finite element model of the tire obtained by dividing the created overall model into finite elements. create.

  Further, the model creation unit 52a appropriately creates a rim model (a rim model or a wheel model including a rim model) in contact with the tire, a road surface model (road surface model) in contact with the tire, as necessary. Then, the model creation unit 52 a stores the laminated plate finite element model (see FIG. 3), the tire finite element model, and other models in the storage unit 54. The whole model and other models are used as analysis models for deformation analysis (simulation) executed by the analysis unit 52c described later, either alone or in combination depending on the simulation method.

  The condition setting unit 52b sets various conditions for executing the analysis using the laminated plate finite element model (see FIG. 3) created by the model creating unit 52a and the analysis using the tire finite element model. . The condition setting unit 52 b sets various conditions based on the operation detected by the input unit 53 and information stored in the storage unit 54. The various conditions include boundary conditions, load conditions, and convergence conditions when executing analysis, design variables that change conditions during analysis, and fixed values that do not change conditions. Design variables include, for example, the number of belts constituting the belt layer of the finite element model of the tire, the position of the belt, the Young's modulus and width of the rubber or coat rubber of the tread, the angle of the belt cord, and the number of ends (unit width) Number of cords per unit), rigidity, and shape and size of the carcass layer.

  In the present embodiment, the condition setting unit 52b uses the internal pressure of the pneumatic tire 1 as a predetermined tensile load applied to the laminated plate finite element model M3 during deformation analysis performed by the analysis unit 52c described later. As a predetermined three-point bending load to be applied to the laminated plate finite element model M3, a ground load (indentation load or indentation displacement) acting on the pneumatic tire 1 when grounded is set. ) To set the tension assumed to be applied to the belt layer 14. In the present embodiment, the condition setting unit 52b appropriately changes the arrangement position of the 0 degree [deg] belt in the laminated plate finite element model M3 in the deformation analysis executed by the analysis unit 52c described later.

  In the present embodiment, an internal pressure test of a tire that is actually filled with air into a tire to be analyzed is performed, and a tire growth amount (rate) due to the internal pressure is measured for each part. The part includes a center groove 21 (for example, refer to 21 in FIG. 1), an intermediate groove 22 (for example, refer to 22 in FIG. 1), and a shoulder groove 23 (for example, refer to 23 in FIG. 1) of the tread portion 33. And in this embodiment, the growth amount (rate) of the tire measured for every site | part is recorded.

  The analysis unit 52c executes analysis (simulation) using the laminated plate finite element model (see FIG. 3) created by the model creation unit 52a and analysis (simulation) using the tire finite element model. Details of the analysis will be described later.

  The processing unit 52 includes, for example, a memory and a CPU (Central Processing Unit). When executing the various processes according to the present embodiment, the processing unit 52 reads the computer program from the storage unit 54 and expands it in the memory. The computer program expanded in the memory functions as a process for executing various processes according to the present embodiment. For example, this process expands various data such as the analysis model and input data from the storage unit 54 to an area allocated to itself on the memory as appropriate, and performs various processes related to tire analysis based on the expanded data. Run. In this process, data related to various processes relating to tire analysis is appropriately stored in the storage unit 54, and the process is performed by appropriately reading out data from the storage unit 54 as necessary.

  The display means 55 is a display device such as a liquid crystal display device. The storage unit 54 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 simulation method according to the present embodiment will be described with reference to FIGS. The tire simulation method according to this embodiment can be realized by the analysis device 50 described above.

  5 and 6 are flowcharts showing a processing procedure of the tire simulation method according to the present embodiment. As will be described below, the tire simulation method according to the present embodiment is a laminated plate finite which is an analytical model in which parts constituting the belt layer 14 of the pneumatic tire 1 are laminated and divided into a plurality of elements. It is executed using an element model.

  As illustrated in FIG. 5, for example, when the setting of the tire specification is received via the input unit 53, the analysis unit 52c determines the tire specification (step S101). For example, the analysis unit 52c determines the tire specifications for the heavy duty radial tire (see FIG. 1).

  The analysis unit 52c acquires the tire growth amount (rate) obtained as a result of the tire internal pressure test from the storage unit 54 (step S102). FIG. 7 is a diagram illustrating a data example of a tire growth amount (rate) by a tire internal pressure test. As shown in FIG. 7, the tire growth amount (rate) data acquired by the analysis unit 52c from the storage unit 54 includes a structure in which the belt layer 14 is composed of four parts (hereinafter, a four-belt structure). An internal pressure test was actually performed on the pneumatic tire 1 having the belt layer 14 and the pneumatic tire 1 having the belt layer 14 having a structure in which the belt layer 14 is composed of five parts (hereinafter referred to as five-belt structure). Data of time is included. The four-belt structure corresponds to a structure in which no belt is disposed on the belt layer 14. The five-sheet belt structure structure corresponds to a structure (see FIG. 4) in which a 0-degree belt is disposed at the center (3B position) of the belt layer 14. Further, as shown in FIG. 7, the tire growth amount (rate) data acquired from the storage unit 54 by the analysis unit 52 c includes the center groove 21, the intermediate groove 22, and the shoulder groove of the tort portion 33 of the pneumatic tire 1. The growth amount and growth rate for each of the 23 sites are included. The data shown in FIG. 7 is an example and is not limited to the example shown in FIG.

  Subsequently, the analysis unit 52c acquires, from the storage unit 54, a laminated plate finite element model M3 (see FIG. 3) in which parts constituting the belt layer 14 (see FIG. 1) of the pneumatic tire 1 to be analyzed are laminated. (Step S103). The laminated plate finite element model M3 is created by the model creation unit 52a. The model creation unit 52 a reads data for modeling each part constituting the belt layer 14 from the storage unit 54. Subsequently, the model creation unit 52a uses the data read from the storage unit 54 to sequentially stack and model the parts constituting the belt layer 14, and then divide the model into a finite number of elements. A plate-like laminated plate finite element model M3 as shown in FIG. 3 is created.

  Subsequently, the analysis unit 52c sets boundary conditions and load conditions for deformation analysis (simulation) of the laminated plate finite element model M3 (step S104), and executes deformation analysis (simulation) of the laminated plate finite element model M3. (Step S105). FIG. 8 is a diagram showing an image when a tensile load is applied to the laminated plate finite element model. As shown in FIG. 8, the analysis unit 52c performs deformation analysis when a predetermined tensile load F1 is applied to the laminated plate finite element model M3. The predetermined tensile load F1 is, for example, a tension assumed to be applied to the belt layer 14 by the internal pressure of the pneumatic tire 1, and an arbitrary value is appropriately set.

  Subsequently, the analysis unit 52c outputs the result of the deformation analysis of the laminated plate finite element model M3 in step S105 (step S106). For example, the analysis unit 52c appropriately changes a predetermined tensile load F1 applied to the laminate finite element model M3, and calculates the elongation (%) of the laminate finite element model M3 corresponding to the tensile load F1. The elongation (%) is a value of the elongation rate with respect to the entire length of the laminated plate finite element model M3. Then, the analysis unit 52c compares the actual tire internal pressure test result obtained in step S102 (see FIG. 7) with the actual tire from the deformation analysis results of the laminated plate finite element model M3. Outputs analysis results that match the tendency of tire growth (rate) in the internal pressure test.

  FIG. 9 is a diagram illustrating an example of an analysis result when a tensile load is applied to the laminated plate finite element model. FIG. 9 shows the relationship between the load (kgf) acting on the laminated plate finite element model corresponding to the belt layer of the four-belt structure and the elongation (%) due to the load, and the lamination corresponding to the belt layer of the five-belt structure. The graph showing the relationship between the load (kgf) acting on the plate finite element model M3 and the elongation (%) due to the load is shown. As shown in FIG. 7 described above, according to the internal pressure test of the pneumatic tire 1 having a belt layer having a four-belt structure, the growth rate of the shoulder groove 23 is 0.48%. In the graph of the laminated plate finite element model corresponding to the belt layer having the four-belt structure shown in FIG. 30 (kgf). Furthermore, when a load of 46.30 (kgf) is applied to the graph of the laminated plate finite element model corresponding to the belt layer of the five-belt structure shown in FIG. 9, the elongation (%) becomes 0.26%. . Furthermore, as shown in FIG. 7 described above, according to the internal pressure test of the pneumatic tire 1 having the belt layer of the five-belt structure, the growth rate of the shoulder groove 23 is 0.27%. Therefore, the growth rate of the shoulder groove 23 obtained from the result of the internal pressure test of the pneumatic tire 1 having the belt layer of the five-belt structure and the elongation of the laminated plate finite element model M3 corresponding to the belt layer of the five-belt structure ( %) Is almost the same. Therefore, the analysis unit 52c outputs 46.30 (kgf) as the analysis result of the laminated plate finite element model M3 corresponding to the belt layer of the five-belt structure. That is, the analysis unit 52c includes, for example, 5 pieces of tension (tension corresponding to the internal pressure of the pneumatic tire 1) assumed to be applied to the belt layer when the internal pressure of the pneumatic tire 1 acts on the belt layer. 46.30 (kgf) is output as a load corresponding to the growth rate of the shoulder groove 23 of the pneumatic tire 1 having the belt layer of the belt structure.

  The analysis part 52c respond | corresponds to the growth rate of the intermediate groove | channel 22 which the load corresponding to the growth rate of the center groove | channel 21 which the tire part 33 of the pneumatic tire 1 has, and the trough part 33 of the pneumatic tire 1 by the same method. Can output the load. For example, the analysis unit 52c is an air having a belt layer having a five-belt structure based on the analysis result of the laminated plate finite element model M3 shown in FIG. 9 and the result of the internal pressure test of the pneumatic tire 1 shown in FIG. 27.90 (kgf) is output as a load corresponding to the growth rate of the center groove 21 of the entering tire 1. Moreover, the analysis part 52c is the air which has a belt layer of a 5-sheet belt structure based on the analysis result of the laminated sheet finite element model M3 shown in FIG. 9, and the result of the internal pressure test of the pneumatic tire 1 shown in FIG. 40.49 (kgf) is output as a load corresponding to the growth rate of the intermediate groove 22 of the entering tire 1.

  Subsequently, as shown in FIG. 6, the analysis unit 52c acquires a finite element model of the entire tire from the storage unit 54 (step S107a), and sets boundary conditions and load conditions (step S107b). After setting the boundary condition and the load condition, the analysis unit 52c performs a ground deformation analysis of the finite element model of the entire tire (step S107c). And the analysis part 52c outputs the analysis result of the ground deformation analysis in step S107c (step S107d). In step S107d, a tension that is assumed to be applied to the belt layer 14 when the pneumatic tire 1 is grounded is obtained. In step S107d, as the tension that is assumed to be applied to the belt layer 14 when the pneumatic tire 1 is grounded, for each part of the pneumatic tire 1, for example, the center groove 21, the intermediate groove 22, the shoulder, A tension corresponding to each part of the groove 23 is obtained.

  Further, the analysis unit 52c acquires the laminated plate finite element model M3 in which the parts constituting the belt layer 14 of the pneumatic tire 1 to be analyzed are stacked from the storage unit 54 (step S108a), and boundary conditions and load conditions Is temporarily set (step S108b). In step 108b, the load condition temporarily set by the analysis unit 52c includes a predetermined tensile load and a predetermined three-point bending load. Of the load conditions temporarily set by the analysis unit 52c, a predetermined tensile load corresponds to a load value output as a result of the deformation analysis in step S106.

  After temporarily setting the boundary condition and the load condition, the analysis unit 52c executes a temporary deformation analysis of the laminated plate finite element model M3 with a predetermined tensile load and a predetermined three-point bending load (step S108c). The temporary deformation analysis in step S108c may be performed for each part of the pneumatic tire 1, for example, each part of the center groove 21, the intermediate groove 22, and the shoulder groove 23 of the tort portion 33, or only for a specific part. May be executed.

  FIG. 10 is a diagram showing an image when a tensile load and a three-point bending load are applied to the laminated plate finite element model. As shown in FIG. 10, the analysis unit 52c performs deformation analysis when a predetermined tensile load F1 and a predetermined three-point bending load F2 are applied to the laminated plate finite element model M3. The predetermined tensile load F1 is a tension assumed to be applied to the belt layer 14 by the action of the internal pressure of the pneumatic tire 1, and corresponds to the result of the deformation analysis output in step S106. For example, when the analysis corresponding to the shoulder groove 23 is executed, 46.30 (kgf) is set as the predetermined tensile load F1. The predetermined three-point bending load F2 is a tension that is assumed to be applied to the belt layer 14 by a grounding load (pushing load) that acts on the pneumatic tire 1 when the pneumatic tire 1 is grounded, and the analysis unit 52c. Thus, an arbitrary value is temporarily set as appropriate. Further, the analysis unit 52c fixes one end of the laminated plate finite element model M3, for example, as shown in FIG. 10 in accordance with the state of the load acting on the belt layer 14 when the pneumatic tire 1 is grounded. The deformation of the laminate finite element model M3 when a predetermined three-point bending load F2 is applied in a state where the tensile load F1 is applied is analyzed. Furthermore, when a predetermined three-point bending load F2 is applied, a distance H between fulcrums for performing the three-point bending is set as shown in FIG. The distance H may be set to, for example, 10 mm to 1500 mm, preferably 20 to 300 mm, and is set to 50 mm in this embodiment. In step S108c, the temporary deformation analysis performed by the analysis unit 52c is for realizing, in the laminated plate finite element model M3, the analysis corresponding to the ground deformation analysis of the finite element model of the entire tire performed in step S107c. It is. In the deformation analysis of the laminated plate finite element model M3, the force applied to the belt layer 14 when the pneumatic tire 1 is grounded is expressed by a three-point bending load due to the tensile load due to the internal pressure of the pneumatic tire 1 and the ground load of the pneumatic tire 1. (See FIG. 10).

  And the analysis part 52c outputs the analysis result of the temporary deformation | transformation analysis in step S108c (step S108d). In step S108d, the tension (the tension due to the internal pressure and the tension applied to the belt layer 14 due to the ground load) that is assumed to be applied to the belt layer 14 when the pneumatic tire 1 is grounded is obtained.

  When the analysis result of step S107d and the analysis result of step S108d are output, the analysis unit 52c causes the tire tension obtained from the tension of the belt layer 14 at the time of tire contact obtained from the analysis result of step S107d and the analysis result of step S108d. It is determined whether or not the tension of the belt layer 14 at the time of grounding matches (step S109). In step S109, in order to perform analysis at the time of tire contact using the laminated plate finite element model M3 by the analysis unit 52c, a belt obtained by analysis at the time of contact of the pneumatic tire 1 using a finite element model of the entire tire. The tension of the layer 14 and the tension of the belt layer 14 obtained by temporary deformation analysis using the laminated plate finite element model M3 are combined. That is, step S109 is processing for deriving a value to be set as the tension applied to the belt layer 14 at the time of tire contact when performing analysis at the time of tire contact using the laminated plate finite element model M3.

  As a result of the determination, when the tension of the belt layer 14 at the time of tire contact obtained from the analysis result of step S107d does not match the tension of the belt layer 14 at the time of tire contact obtained from the analysis result of step S108d (step S109). No), the analysis unit 52c corrects the load condition (three-point bending load) temporarily set in step S108b (step S110). After correcting the load condition (three-point bending load), the analysis unit 52c returns to step S108b and re-executes the processing from step S108b to step S109.

  In step S109, as a result of the determination, when the tension of the belt layer 14 at the time of tire contact obtained from the analysis result of step S107d matches the tension of the belt layer 14 at the time of tire contact obtained from the analysis result of step S108d. (Step S109, Yes), the analysis unit 52c finally determines a load condition for deformation analysis of the laminated plate finite element model M3 (Step S111).

  After the final determination of the load condition, the analysis unit 52c executes deformation analysis (interlayer strain analysis) of the laminated plate finite element model M3 (step S112). The analysis unit 52c appropriately changes the arrangement position of the 0 degree belt in the laminated plate finite element model M3, and analyzes the interlayer strain for each arrangement position of the 0 degree belt. And the analysis part 52c outputs the analysis result in step S112 (step S113), and complete | finishes the process sequence shown in FIG.5 and FIG.6.

  The laminated plate finite element model M3 (see FIG. 3) and the finite element model of the entire tire are models used for performing deformation analysis using a numerical analysis method such as a finite element method or a finite difference method. For example, in the present embodiment, a finite element method (FEM: Finite Element Method) is used for deformation analysis (such as FIGS. 5 and 6) of the finite element model M3 of the laminated plate or the entire tire. For this reason, the laminated plate finite element model M3 and the finite element model of the entire tire are created based on the finite element method. Since the finite element method is an analysis technique suitable for structural analysis, it can be suitably applied particularly to a structure such as a tire. The analysis method applicable to the deformation analysis (FIGS. 5 and 6 and the like) in the present embodiment is not limited to the finite element method, but is a finite difference method (FDM), a boundary element method (BEM), or a boundary element method (BEM). Etc. can also be used. Further, the most appropriate analysis method can be selected according to the boundary condition or the like, or a plurality of analysis methods can be used in combination.

  The laminated plate finite element model M3 (see FIG. 3) and the finite element model of the entire tire are divided into a plurality of finite elements. Each of the plurality of elements is composed of a plurality of nodes, and becomes, for example, an analysis model having a three-dimensional shape. For example, in the case of a three-dimensional body, the tire model has a solid element such as a tetrahedral solid element, a pentahedral solid element, a hexahedral solid element, a triangular shell element, a shell element such as a quadrangular shell element, a plane element, etc. It is desirable to make it an element that can be handled. In the process of analysis, the elements divided in this way are identified one by one using three-dimensional coordinates and cylindrical coordinates in the three-dimensional model.

  The analysis results obtained by the tire simulation method according to the present embodiment will be described with reference to FIGS.

  FIG. 11 is a diagram comparing the result of deformation analysis of the laminated plate finite element model M3 corresponding to the belt layer 14 having the five-belt structure and the experimental result of the pneumatic tire 1 having the belt layer 14 having the five-belt structure. It is. As shown in FIG. 11, the growth rate of the center groove, the intermediate groove, and the shoulder groove obtained from the result of the internal pressure test of the pneumatic tire 1 having the belt layer 14 of the five-belt structure, and the belt layer of the five-belt structure The result was that the elongation (%) of the corresponding laminated plate finite element model M3 almost coincided. That is, the analysis result equivalent to the test for measuring the internal pressure growth of the pneumatic tire 1 can be obtained by the deformation analysis of the laminated plate finite element model M3 corresponding to the belt layer 14. For this reason, according to the present embodiment, it is possible to realize simple and accurate performance analysis of the pneumatic tire 1.

  FIG. 12 shows the correlation between the result of the running test of the pneumatic tire 1 and the analysis result of the interlayer strain of the belt layer 14 obtained as a result of the deformation analysis of the laminated plate finite element model M3 for each 0 degree belt arrangement position. FIG. In FIG. 12, for example, the travel distance and interlayer strain values corresponding to the five-belt structures D1 to D3 are represented by an index when the value corresponding to the four-belt structure is “100”. FIG. 12 shows the correlation between the results of the running experiment and the analysis result of the interlayer strain for the belt layer 14 of the four-belt structure, the five-belt structure D3, the five-belt structure D2, and the five-belt structure D1. ing. As described above, the four-belt structure is composed of four parts and does not have a 0-degree belt, and the five-belt structure D3 is composed of five parts and has a central layer (3B This is a structure in which a 0 degree belt is arranged at the position (see FIG. 4). The five-sheet belt structure D2 is composed of five parts, and is a structure in which a 0-degree belt is arranged on the second layer (2B position, see FIG. 4) from the inner diameter side of the pneumatic tire 1. The sheet belt structure D1 structure is composed of five parts, and is a structure in which a belt of 0 degrees is arranged on the innermost layer (1B position, see FIG. 4) of the pneumatic tire 1.

  As shown in FIG. 12, in the running experiment of the pneumatic tire 1, the pneumatic tire 1 having the belt layer 14 including the 0 degree belt has a longer traveling distance and less interlayer distortion (high durability). It has been. On the other hand, in the deformation analysis of the laminated plate finite element model M3, a result is obtained that the interlayer finite element model M3 corresponding to the belt layer 14 including the 0 degree belt has less interlayer strain. Therefore, a tendency that matches the actual situation that the pneumatic tire 1 having the 0 degree belt has higher durability is reproduced by the deformation analysis of the laminated plate finite element model M3.

  Also, as shown in FIG. 12, in the deformation analysis of the laminated plate finite element model M3, an interlayer strain is obtained for each 0-degree belt arrangement position. In the example shown in FIG. 12, it can be seen that the belt layer 14 of the five-belt structure D1 has the least interlayer strain and high durability as compared with the belt layer 14 having the five-belt structure D3 or the five-belt structure D2. As described above, by the deformation analysis of the laminated plate finite element model M3, it is possible to analyze the difference in durability of the pneumatic tire 1 due to the difference in the arrangement position of the 0 degree belt.

  In the present embodiment, the interlayer finite element model M3 in which the parts constituting the belt layer 14 are laminated is used to analyze the interlayer strain in the belt layer when the pneumatic tire 1 is in contact with the ground. Compared to analysis using a finite element model, the amount of data required for analysis can be greatly reduced. In addition, as described above, the tendency of the interlayer distortion (durability of the pneumatic tire 1) at the time of contact of the pneumatic tire 1 can be reproduced well. For this reason, according to the present embodiment, it is possible to realize a simple and accurate tire performance analysis while reducing the burden.

  FIG. 13 is a diagram comparing the analysis result by the tensile load and the three-point bending load according to the present embodiment and the analysis result by the conventional three-point bending. In FIG. 13, for example, the value of the interlayer strain corresponding to the five-belt structure D1 to D3 is represented by an index when the value corresponding to the four-belt structure is set to “100”. FIG. 14 is a view showing a modified example of the laminate finite element model by the tensile load and the three-point bending load according to the present embodiment. FIG. 15 is a diagram showing a modified example of the laminated plate finite element model by the conventional three-point bending method. Note that the conventional three-point bending test is disclosed in, for example, Japanese Patent No. 4822711.

  In the deformation analysis by tension and three-point bending according to the present embodiment, for example, as shown in FIG. 14, the belt layer 14 of the four-belt structure, the five-belt structure D3, the five-belt structure D2, and the five-belt structure D1. Deformation analysis when a tensile load and a three-point bending load are applied with one end fixed to each laminated plate finite element model corresponding to is performed. On the other hand, in the deformation analysis using the conventional three-point bending method as a comparative example, for example, as shown in FIG. 15, a four-belt structure, a five-belt structure D3, a five-belt structure D2, and a five-belt structure D1. For each laminated plate finite element model corresponding to the belt layer 14, deformation analysis is performed when only a three-point bending load is applied without fixing both ends. As a result, as shown in FIG. 13, in the deformation analysis by tension and three-point bending according to the present embodiment, a result is obtained that the model having the 0 degree belt has less interlayer strain. Similar to the example shown in FIG. 12, the result is a good reproduction of the tendency to match the actual situation that the durability is higher as the belt layer 14 has a 0 degree belt. On the other hand, as shown in FIG. 13, in the deformation analysis using the conventional three-point bending method as a comparative example, the belt layer 14 that does not have the 0 degree belt is more than the belt layer 14 that has the 0 degree belt. As a result, the inter-layer strain is small, and the tendency that the durability is so high that the belt layer 14 has the 0 degree belt cannot be reproduced. For this reason, in the present embodiment, it is possible to realize an analysis that conforms to the fact that the higher the belt layer 14 has a 0 degree belt, the higher the durability, by deformation analysis by tension and three-point bending.

  Further, in the present embodiment, by using a laminated plate finite element model in which the parts constituting the belt layer 14 are stacked and modeled, internal pressure growth of the pneumatic tire 1 and interlayer strain of the belt layer 14 (of the pneumatic tire 1). The tire simulation method for easily and accurately reproducing the durability) has been described. However, the present invention is not limited to modeling the parts constituting the belt layer 14, and a model in which parts other than the belt layer 14 constituting the pneumatic tire 1 are laminated is created to increase the internal pressure of the pneumatic tire 1. And durability may be used for analysis. In addition to the pneumatic tire 1, the analysis method according to the present embodiment may be applied to a product generated by combining a plurality of materials.

  Moreover, in this embodiment, the analysis apparatus 50 can output the data of the interlayer distortion of the belt layer 14 as an analysis result obtained by the simulation of the tire, for example, and thereby the durability of the pneumatic tire 1 can be evaluated. As a result, it can contribute to the evaluation of tire characteristics. It is possible to design a tire having excellent durability by reducing the interlayer strain. Further, the growth amount can be calculated by the tensile analysis of the laminated plate model, and thereby, it is possible to evaluate the uneven wear property of the tire. A tire having excellent uneven wear resistance can be designed by making the growth of the center portion, shoulder portion, and intermediate portion between them small and uniform.

  In addition, you may manufacture a tire based on the result of the simulation of the tire which concerns on this embodiment. For example, the belt width, angle, arrangement, number of ends, and stress-strain characteristics of the material of the belt layer 14 based on the interlayer strain and growth amount data of the belt layer 14 obtained as a result of the simulation of the tire according to the present embodiment. Thus, it is possible to quickly and appropriately determine design parameters such as and to select an optimal belt structure. And a tire is manufactured by producing | generating the green tire containing the belt layer 14 produced | generated based on this design method.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 50 Analysis apparatus 51 Input / output device 52 Processing part 52a Model preparation part 52b Condition setting part 52c Analysis part 54 Storage part

Claims (8)

A tire simulation method in which a computer analyzes a tire,
The computer is
A step of performing analysis when a predetermined tensile load and a predetermined three-point bending load are applied to the tire analysis model in which a plurality of parts constituting the tire are stacked and divided into a plurality of finite elements. And a tire simulation method, wherein The analysis model is
The tire simulation method according to claim 1, wherein the tire is a model in which parts constituting the belt layer of the tire are stacked and divided into a finite number of elements.   In the step of performing the analysis executed by the computer, the predetermined tensile load given to the analysis model corresponds to a tension applied to the belt layer by an internal pressure of the tire due to filled air, 3. The tire according to claim 2, wherein the predetermined three-point bending load applied to the analytical model corresponds to a tension applied to the belt layer by a ground load acting on the tire at the time of ground contact. Simulation method. The computer is
The step of performing the analysis includes determining a value of the predetermined tensile load based on a result of measuring a growth rate for each predetermined portion of the tire by performing a test for filling the tire with air. Item 4. The tire simulation method according to Item 3. The computer is
In the step of performing the analysis, determining a value of the predetermined three-point bending load based on a calculation result of a load applied to the belt layer when the tire contacts the ground using the entire tire model. The tire simulation method according to claim 4, wherein: A tire characteristic evaluation method for evaluating tire characteristics based on tire analysis results executed by a computer,
The computer is
Analysis is performed when a predetermined tensile load and a predetermined three-point bending load are applied to the tire analysis model in which the parts constituting the belt layer of the tire are stacked and divided into a plurality of finite elements. Steps,
Outputting the inter-layer strain data of the belt layer obtained by the analysis. A method for evaluating tire characteristics, comprising: A tire manufacturing method for manufacturing a tire, comprising:
When a predetermined tensile load and a predetermined three-point bending load are applied to the tire analysis model obtained by laminating the parts constituting the belt layer of the tire and dividing the computer into a finite number of elements. Performing the analysis; and
Determining a design method of the belt layer based on data of interlayer strain of the belt layer obtained by the analysis;
Generating a green tire including a belt layer generated according to the design method.   A pneumatic tire manufactured by the tire manufacturing method according to claim 7.

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