JP5577848B2 - Tire simulation test method, tire simulation computer program, and tire simulation test apparatus - Google Patents

Description

  The present invention relates to a tire simulation test method for calculating various physical quantities of a tire by simulation, a computer program for tire simulation, and a tire simulation test apparatus.

  In addition to experiments using prototypes, tires under development are repeatedly tested by simulation. In the test by simulation, it is not necessary to actually create a prototype, so that the time required for tire development can be shortened compared to the experiment using the prototype, and the cost required for tire development can be reduced. For example, in Patent Document 1, rolling is performed on a road surface model while applying a load to a tire model, then a contact reaction force generated between the tire model and the road surface model is acquired, and the acquired contact reaction force is acquired. A technique for evaluating pattern noise of a tire model based on force fluctuation is disclosed.

JP 2009-20123 A

  When an actual tire rolls, its rigidity decreases. Patent Document 1 does not take into consideration the property of the tire that the rigidity decreases when it rolls. Therefore, in order to calculate the various physical quantities of the tire more accurately, it is preferable to take into account the property of the tire that the rigidity decreases when rolling.

  The present invention has been made in view of the above, and an object thereof is to more accurately calculate various physical quantities of a tire.

  In order to solve the above-described problems and achieve the object, a tire simulation test method according to the present invention includes a friction coefficient between a tire model expressing a tire and a road surface model expressing a road surface in contact with the tire. And applying a predetermined load to the tire model to contact the road surface model, rolling the tire model until the predetermined condition is satisfied while keeping the load constant, and the predetermined condition is satisfied. After that, the distance between the axial road surfaces between the rolling axis of the tire model and the road surface model is set as a set value, and while maintaining the distance between the axial road surfaces constant at the set value, a physical analysis is performed by performing a rolling analysis. It is characterized by calculating.

  As a preferred aspect of the present invention, every time the tire model rolls and moves a predetermined amount, an average value of the distance between the axial road surfaces while the tire model rolls and moves a predetermined amount is calculated, It is desirable to determine that the predetermined condition is satisfied when a difference between two average values adjacent to each other among the average values calculated a plurality of times is equal to or less than a threshold value.

  As a preferred aspect of the present invention, it is desirable that the predetermined condition is determined to be satisfied when the distance that the tire model has rolled exceeds a threshold after the tire model has started rolling.

  As a preferred aspect of the present invention, it is desirable that the threshold value is a value equal to or greater than a contact length of the tire model.

  As a preferred aspect of the present invention, the set value is an average value of the distance between the axial road surfaces while the tire model rolls and moves by a predetermined amount after the predetermined condition is satisfied. desirable.

  As a preferred aspect of the present invention, it is desirable to calculate the physical quantity during the rolling of the tire model by a distance of one pitch or more of the pattern formed on the tire.

  As a preferred aspect of the present invention, it is desirable to calculate the physical quantity each time the tire model rolls by a distance equal to or less than ¼ pitch of the pattern formed on the tire.

  As a preferred aspect of the present invention, the rolling analysis is preferably a quasi-static analysis.

  As a preferred aspect of the present invention, it is desirable that the tire model rolls freely with relative displacement between the tire model and the road surface model.

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

  In order to solve the above-described problems and achieve the object, a tire simulation test apparatus according to the present invention includes a storage unit that stores the above-described tire simulation computer program, and the tire simulation computer from the storage unit. And a processing unit that acquires a program and executes the tire simulation computer program.

  The present invention can calculate various physical quantities of a tire more accurately.

FIG. 1 is a partial cross-sectional view showing a cross section of a tire cut along a meridian plane including a rotation axis of the tire. FIG. 2 is a partial plan view showing an example of a tread pattern formed on the tread surface. FIG. 3 is an explanatory diagram showing the configuration of the tire vibration characteristic evaluation apparatus of the present embodiment. FIG. 4 is a flowchart showing a processing procedure of the tire vibration characteristic evaluation method of the present embodiment. FIG. 5 is a perspective view showing an example of a tire model in which a tire is divided into minute elements. FIG. 6 is a perspective view showing an example of a wheel model. FIG. 7 is a perspective view showing an example in which a tire model is assembled to a wheel model. FIG. 8 is an explanatory diagram showing a state in which the tire model is in contact with the road surface model. FIG. 9 is a flowchart showing a series of procedures for determining whether or not a predetermined condition is satisfied. FIG. 10 is a graph showing the distance between the axial road surfaces for each rolling angle. FIG. 11 is a flowchart showing another series of procedures for determining whether or not a predetermined condition is satisfied. FIG. 12 shows that when the set value of the distance between the axial road surfaces is kept constant at the distance between the axial road surfaces when the tire model is stationary and a constant load is applied to the tire model, the tire model receives from the road surface model. It is a graph which shows reaction force for every rotation angle of a tire model. FIG. 13 shows the rotational angle of the tire model when the tire model keeps the set value of the distance between the road surfaces constant at a constant value and the tire model applies a reaction force received from the road surface model when a constant load is applied to the tire model. It is a graph shown for every.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the best mode for carrying out the invention. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same. The present invention can be applied to all tires and is not limited to pneumatic tires.

(Embodiment)
In the following description, as an example of the simulation test, a test for evaluating the vibration characteristics (pattern noise) of the tire based on the reaction force generated between the tire model and the road surface model will be described. However, the simulation test of the present embodiment is a test for evaluating various physical quantities of the tire while rolling the tire model, that is, a test for evaluating the vibration characteristics (pattern noise) of the tire if rolling analysis is performed. It is not limited. Before describing the method for evaluating vibration characteristics of a tire according to the present embodiment, a tire that is an evaluation target will be described.

  FIG. 1 is a partial cross-sectional view showing a cross section of a tire cut along a meridian plane including a rotation axis of the tire. FIG. 2 is a partial plan view showing an example of a tread pattern formed on the tread surface. The tire 10 includes a cap tread 11, an under tread 13, a side tread 14, a belt 15, a carcass 16, a bead 17, and a bead filler 18. The cap tread 11 is a part that contacts the road surface. The cap tread 11 is a rubber layer that covers the belt 15 and the carcass 16. The surface where the cap tread 11 is in contact with the road surface is referred to as a tread surface 11a. The tread surface 11a is divided by a plurality of grooves 12 as shown in FIG. The groove 12 includes a plurality of vertical grooves 12a and a plurality of horizontal grooves 12b. The tread surface 11a is divided in the circumferential direction of the tire 10 (arrow direction in FIG. 2) by the lateral grooves 12b. Further, the tread surface 11a is divided in a direction orthogonal to the circumferential direction of the tire 10 by the vertical grooves 12a. Thereby, a plurality of blocks 11b are formed on the tread surface 11a. The circumferential length of the one block 11b is referred to as 1 pitch P.

  The under tread 13 shown in FIG. 1 is a rubber layer disposed between the cap tread 11 and the belt 15. The side tread 14 is disposed on the outermost side of the sidewall portion. The belt 15 is a cord layer disposed between the cap tread 11 and the carcass 16. In the case of a bias tire, it is called a breaker. The carcass 16 is a rubberized cord layer that forms the skeleton of the tire 10. The carcass 16 is a strength member that serves as a pressure vessel when the tire 10 is filled with air. The carcass 16 is configured to support a load by an internal pressure of air and to withstand a dynamic load during traveling. The bead 17 is a ring in which a bundle of steel wires is hardened with hard rubber. The bead 17 plays a role of fixing the tire 10 to the rim of the wheel and secures the strength of the tire 10. The bead filler 18 is a rubber filled in a space generated when the carcass 16 is wound around the bead wire. The bead filler 18 fixes the carcass 16 to the bead 17 and adjusts the shape of the portion. Further, the bead filler 18 increases the rigidity of the entire bead portion.

  When the tire in which the groove 12 is formed on the tread surface 11a rolls, the block 11b contacts the road surface. Noise occurs when the block 11b leaves the road surface. This noise is called pattern noise, and changes depending on the shape of the tread pattern formed by the groove 12. A tire having a tread pattern is preferably designed so that the pattern noise can be reduced. Hereinafter, a vibration characteristic evaluation apparatus that performs a simulation test for reducing the pattern noise will be described.

  FIG. 3 is an explanatory diagram showing the configuration of the tire vibration characteristic evaluation apparatus of the present embodiment. A vibration characteristic evaluation apparatus 30 as a simulation test apparatus includes a processing unit 40, a storage unit 31, and an input / output port (I / O) 32. The processing unit 40 and the storage unit 31 are electrically connected via the input / output port 32. The processing unit 40 is configured by, for example, a CPU (Central Processing Unit). The processing unit 40 includes a model creation unit 41, a tire mounting unit 42, a rolling analysis unit 43, and a contact reaction force analysis unit 44. These execute the tire vibration characteristic evaluation method of this embodiment. The model creation unit 41, the tire mounting unit 42, the rolling analysis unit 43, and the contact reaction force analysis unit 44 are electrically connected to the input / output port 32, respectively. Thereby, the model creation part 41, the tire mounting part 42, the rolling analysis part 43, and the contact reaction force analysis part 44 can mutually exchange data.

  The terminal device 50 is electrically connected to the input / output port 32 of the present embodiment. The terminal device 50 has data necessary for executing the tire vibration characteristic evaluation method according to the present embodiment, for example, the physical property value of the rubber constituting the tire 10, the physical property value of the wheel, or the boundary condition or running in the rolling analysis. This is a device for giving conditions and the like to the vibration characteristic evaluation device 30. These data are input by an input device 51 that is electrically connected to the terminal device 50. Further, the terminal device 50 receives the tire vibration characteristic evaluation result from the vibration characteristic evaluation device 30 and displays the result on the display device 52 electrically connected to the terminal device 50. Further, a data server that stores various databases may be electrically connected to the input / output port 32 via the terminal device 50. In executing the tire vibration characteristic evaluation method of the present embodiment, the vibration characteristic evaluation apparatus 30 is configured to acquire various databases stored in the data server.

  The storage unit 31 stores a computer program including a processing procedure of the tire vibration characteristic evaluation method of the present embodiment, and data such as material properties acquired from a data server. The storage unit 31 is configured by, for example, a volatile memory, a nonvolatile memory, or a combination thereof. Moreover, the process part 40 can be comprised by CPU, for example. The storage unit 31 may be built in the processing unit 40 or may be in another device (for example, a database server). Thus, the vibration characteristic evaluation device 30 may access the processing unit 40 and the storage unit 31 from the terminal device 50 by communication.

  The computer program realizes the processing procedure of the tire vibration characteristic evaluation method of the present embodiment in combination with a computer program already recorded in the model creation unit 41, the contact reaction force analysis unit 44, and the like included in the processing unit 40. It may be possible. Further, the vibration characteristic evaluation apparatus 30 uses a dedicated hardware instead of the computer program, and a model creation unit 41, a tire mounting unit 42, a rolling analysis unit 43, and a contact reaction force analysis unit included in the processing unit 40. 44 functions may be realized. Next, a procedure for realizing the tire vibration characteristic evaluation method of this embodiment using the vibration characteristic evaluation apparatus 30 will be described.

  FIG. 4 is a flowchart showing a processing procedure of the tire vibration characteristic evaluation method of the present embodiment. FIG. 5 is a perspective view showing an example of a tire model in which a tire is divided into minute elements. FIG. 6 is a perspective view showing an example of a wheel model. In the tire vibration characteristic evaluation method according to the present embodiment, a finite element method (FEM) is used as an analysis method used for evaluating the vibration characteristic of the tire. The analysis method applicable to the tire vibration characteristic evaluation method of the present embodiment is not limited to the finite element method, and a boundary element method (BEM), a finite difference method (FDM), or the like can also be used. . Further, the most appropriate analysis method can be selected according to the boundary condition or the like, or a plurality of analysis methods can be used in combination. Note that the finite element method is an analysis method suitable for structural analysis, and therefore can be suitably applied particularly to structures such as tires and wheels. The present invention is particularly suitable for predicting various performances of a tire by an explicit method using a finite element method.

  In step ST101 shown in FIG. 4, the model creation unit 41 shown in FIG. 3 creates the tire model 61 as shown in FIG. 5 by expressing the tire 10 shown in FIG. 1 with a plurality of minute elements. Further, the model creation unit 41 creates a road surface model 62 that expresses the road surface with a plurality of minute elements, that is, as shown in FIG. Further, the model creation unit 41 creates a wheel model 63 that expresses a wheel with a plurality of minute elements, that is, as shown in FIG. The microelement based on the finite element method is, for example, a quadrilateral element in a two-dimensional plane, a solid element such as a tetrahedral solid element, a pentahedral solid element, a hexahedral solid element as a three-dimensional body, a triangular shell element, or a rectangular shell element. And so on. The microelements divided in this way are specified using three-dimensional coordinates in the process of analysis.

  The model creation unit 41 creates, for example, the tire model 61, the road surface model 62, and the wheel model 63 by executing a computer program that constitutes a pre-post processor. The order of creating the tire model 61, creating the road surface model 62, and creating the wheel model 63 does not matter. Moreover, although the road surface model 62 of this embodiment is a plane, the road surface model 62 may include unevenness. For example, when the road surface model 62 and the wheel model 63 are stored in advance in the storage unit 31 and the data server shown in FIG. 3, the model creation unit 41 acquires these models via the input / output port 32. May be.

  FIG. 7 is a perspective view showing an example in which a tire model is assembled to a wheel model. Next, in step ST102 shown in FIG. 4, the tire mounting part 42 assembles the tire model 61 to the wheel model 63 as shown in FIG. Specifically, the tire mounting portion 42 first widens the rim width of the rim model of the wheel model 63 to be larger than the width of the bead portion of the tire model 61. The tire mounting portion 42 then fits the rim model to the bead portion of the tire model 61. Thereafter, the tire mounting portion 42 matches the translational freedom in the width direction of the tire model 61 between both rims of the rim model. Thereby, the tire mounting unit 42 creates an assembly model in which the tire model 61 is assembled to the wheel model 63. Next, in step ST <b> 103 shown in FIG. 4, the tire mounting portion 42 shown in FIG. 3 applies an internal pressure to the tire model 61.

  FIG. 8 is an explanatory diagram showing a state in which the tire model is in contact with the road surface model. Next, the rolling analysis unit 43 shown in FIG. 3 rolls the tire model 61 in step ST104 shown in FIG. At this time, the rolling analysis unit 43 keeps the load F acting on the tire model 61 constant as shown in FIG. 8, and sets the friction coefficient between the tire model 61 and the road surface model 62 to a predetermined value. Note that the rolling analysis unit 43 may set, for example, a slip angle, a camber angle, a slip ratio, a lateral force, a longitudinal force, and the like as other conditions. Further, it is more preferable that the rolling analysis unit 43 causes a physical force corresponding to a centrifugal force to act on the minute elements constituting the tire model 61 and the minute elements constituting the wheel model 63. The reason for this will be described below.

  In the analysis of this embodiment, the tire mounting part 42 performs a quasi-static analysis. The quasi-static analysis means that the tire model 61 is rolling at a speed (relative displacement between the tire model 61 and the road surface model 62) that can be handled as if the tire model 61 is stationary. This is an analysis that reproduces this. That is, the rolling analysis unit 43 is an algorithm that assumes a case where the tire model 61 is stationary, and calculates various physical quantities at a minute speed (a minute displacement). The tire model 61 is set so as to roll freely along with the relative displacement between the tire model 61 and the road surface model 62. That is, the rolling analysis unit 43 assumes that the tire model 61 is in a free rolling state.

  Here, as long as the tire model 61 and the wheel model 63 are rolling even at a minute speed, centrifugal force acts on the tire model 61 and the wheel model 63. Therefore, the rolling analysis unit 43 can calculate various physical quantities more accurately by applying a physical force corresponding to a centrifugal force to each minute element of the tire model 61 and the wheel model 63. Next, in step ST105 shown in FIG. 4, the rolling analysis unit 43 determines whether or not a predetermined condition is satisfied. A plurality of specific procedures for determining whether or not a predetermined condition is satisfied are conceivable. Therefore, these procedures will be described below using another flowchart.

  FIG. 9 is a flowchart showing a series of procedures for determining whether or not a predetermined condition is satisfied. FIG. 10 is a graph showing the distance between the axial road surfaces for each rolling angle. By performing a series of procedures shown in FIG. 9, the rolling analysis unit 43 calculates the axial road surface distance h a plurality of times. The axial road surface distance h is a distance between the rotation axis RL of the tire model 61 and the road surface model 62, as shown in FIG. This is because, as shown in FIG. 10, when the tire model 61 starts rolling, the distance h between the axial road surfaces changes. The reason why the distance h between the axial road surfaces changes is that the rigidity of the tire model 61 changes due to rolling.

  In step ST201, the rolling analysis unit 43 calculates an axial road surface distance h shown in FIG. Next, in step ST202, the rolling analysis unit 43 determines whether or not all the distances h between the axial road surfaces for one section have been calculated. One section is a range divided by an angle (hereinafter referred to as a rolling angle) that the tire model 61 rolls. One section is, for example, a range divided every 5 °. In the present embodiment, the tire mounting unit 42 calculates the axial road surface distance h, for example, six times during one section. If it is determined that all the distance h between the axial road surfaces for one section has not been calculated (step ST202, No), the rolling analysis unit 43 returns to step ST201. If it is determined that all the distance h between the axial road surfaces for one section is calculated (step ST202, Yes), the average value AVn of the distance h between the axial road surfaces for one section is calculated in step ST203. In addition, n is a number for distinguishing the average value in each section. That is, the average of the axial road surface distance h in the first section 0 to 5 ° of the section B1 is the average value AV1, and the average of the axial road surface distance h in the nth section Bn is the average value AVn. is there.

  Next, in step ST204, the storage unit 31 stores the average value AVn. Next, the rolling analysis part 43 acquires average value AVn and average value AVn-1 from the memory | storage part 31 by step ST205. The average value AVn−1 is an average of the axial road surface distances h in the section Bn−1 immediately before the nth section Bn. When n is 1, there is no average value AVn-1. Therefore, in this case, the rolling analysis unit 43 substitutes a predetermined initial value for the average value AVn−1, for example. The initial value is set to a value that always makes a negative determination in step ST206 described below.

  Next, in step ST206, the rolling analysis unit 43 calculates a difference between two average values adjacent to each other among the average values AVn calculated a plurality of times, that is, a value obtained by subtracting the average value AVn-1 from the average value AVn. It is determined whether or not the threshold value α is equal to or less. The threshold value α is a value by which it can be determined that the axial road surface distance h has become steady, as in the section B5 and subsequent sections shown in FIG. If it is determined that the value obtained by subtracting the average value AVn-1 from the average value AVn is not equal to or less than the threshold value α (step ST206, No), the rolling analysis unit 43 returns to step ST201. When it is determined that the value obtained by subtracting the average value AVn−1 from the average value AVn is equal to or less than the threshold value α (step ST206, Yes), the rolling analysis unit 43 ends the execution of a series of procedures, and FIG. The process proceeds to step ST106 shown in FIG.

  FIG. 11 is a flowchart showing another series of procedures for determining whether or not a predetermined condition is satisfied. The series of procedures shown in FIG. 11 differs from the series of procedures shown in FIG. 9 in that the axial road surface distance h is not calculated. In step ST301 shown in FIG. 11, the rolling analysis unit 43 shown in FIG. 3 calculates the distance L that the tire model 61 has rolled after starting rolling. The distance L is obtained by an angle at which the tire model 61 has rolled after the tire model 61 has started rolling. Next, in step ST302, the rolling analysis unit 43 determines whether or not the distance L is greater than or equal to the threshold value β. The threshold value β is a value with which it is possible to determine that the axial road surface distance h has become steady as in the section B5 and subsequent sections shown in FIG. The specific threshold value β is the contact length L0 of the tire model 61 shown in FIG. The contact length L0 is a dimension in a direction along the road surface model 62 of a portion of the tire model 61 that contacts the road surface model 62. In many of the tire models 61, when the tire model 61 rotates for the contact length L0, the distance h between the axial road surfaces becomes steady. Therefore, the rolling analysis unit 43 determines that the axial road surface distance h is steady when the distance L is equal to or greater than the threshold value β.

  If step ST302 is performed, the rolling analysis part 43 will complete | finish execution of a series of procedures, and will progress to step ST106 shown in FIG. The series of procedures shown in FIG. 11 requires fewer steps to be executed by the rolling analysis unit 43 than the series of procedures shown in FIG. Therefore, the rolling analysis unit 43 can determine whether the axial road surface distance h has become steady more quickly by executing a series of procedures shown in FIG. On the other hand, the rolling analysis unit 43 calculates a distance h between the axial road surfaces by executing a series of procedures shown in FIG. 9, and determines whether the distance h between the axial road surfaces is steady based on the result. Therefore, the rolling analysis unit 43 can determine whether or not the axial road surface distance h has become steady more accurately by executing a series of procedures shown in FIG.

  Returning to the description of the series of procedures shown in FIG. When it is determined that the predetermined condition is satisfied (step ST105, Yes), the rolling analysis unit 43 proceeds to step ST106. In step ST106, the rolling analysis unit 43 calculates an average value AVn of the axial road surface distance h in one section Bn after the predetermined condition is satisfied. In the present embodiment, as shown in FIG. 10, since the predetermined condition is satisfied in the section B5, the rolling analysis unit 43 calculates the average value AV5 in the section B5. As shown in FIG. 10, the difference in average value AVn in each section Bn after the predetermined condition is satisfied is slight. Therefore, for example, the rolling analysis unit 43 may calculate the average value AV6 in the section B6 or may calculate the average value AVn thereafter. Further, the rolling analysis unit 43 may calculate an average value AVn (average value AV4 in FIG. 10) in the section Bn (section B4 in FIG. 10) immediately before the predetermined condition is satisfied. When obtaining a more accurate value of the axial road surface distance h, it is preferable to calculate the average value AVn in the section Bn after the predetermined condition is satisfied.

  Next, in step ST107, the rolling analysis unit 43 sets the average value AVn calculated in step ST106 as a constant value as the analysis condition. Next, in step ST108, the rolling analysis unit 43 rolls the tire model 61. At this time, the axial road surface distance h is kept constant at the average value AVn. Next, in step ST109, the rolling analysis unit 43 calculates various physical quantities. The various physical quantities include, for example, values indicating the deformation state of the tire model 61, stresses in each part of the tire model 61, strains in each part of the tire model 61, pressures on the contact surface between the tire model 61 and the road surface model 62, and the like. Contact shear stress, reaction force that the tire model 61 receives from the road surface model 62, stress at the center of the rotation axis RL shown in FIG.

  Next, in step ST110, the rolling analysis unit 43 determines whether all the physical quantities in the predetermined section have been calculated. The section here is a displacement amount by which the tire model 61 rolls. For example, as shown in FIG. 2, there are tires 10 in which each pattern is arranged at an equal circumferential pitch. When such a tire 10 is subjected to a rolling analysis, the rolling analysis unit 43 performs a predetermined interval during the rolling of the tire model 61 by a distance of 1 pitch P or more of the pattern formed on the tire 10 shown in FIG. As such, various physical quantities are acquired. This is because the difference between the various physical quantities calculated after the predetermined section and the various physical quantities calculated in the predetermined section is slight. Thereby, since the rolling analysis part 43 can reduce the frequency | count of calculating a physical quantity, it can perform a rolling analysis more rapidly.

  Further, the rolling analysis unit 43 calculates various physical quantities a plurality of times at a predetermined timing during a predetermined section. The predetermined timing is, for example, a timing at which the tire model 61 rolls by a distance equal to or less than a quarter pitch P shown in FIG. That is, the rolling analysis unit 43 calculates various physical quantities every time the tire model 61 rolls by a distance (predetermined amount) of a quarter pitch P or less. Thereby, the rolling analysis unit 43 calculates various physical quantities four times in a predetermined section (while the tire model 61 rolls for a distance of 1 pitch P or more). Thereby, the vibration characteristic evaluation apparatus 30 can provide the user with a change in physical quantity due to a change in the pattern of the contact portion between the tire model 61 and the road surface model 62. In order to provide the user with a change in physical quantity due to a change in the pattern of the contact portion in more detail, it is preferable that the rolling analysis unit 43 obtains various physical quantities, for example, 10 times at regular intervals in a predetermined section. Furthermore, it is more preferable that the rolling analysis unit 43 acquires various physical quantities, for example, 20 times at regular intervals while the tire model 61 rolls for a distance of 1 pitch P or more.

  If it is determined that all the physical quantities in the predetermined section have not been calculated (step ST110, No), the rolling analysis unit 43 returns to step ST108. If it is determined that all the physical quantities in the predetermined section have been calculated (step ST110, Yes), the rolling analysis unit 43 ends the execution of a series of procedures. Next, the effect which the vibration characteristic evaluation apparatus 30 of this embodiment has is demonstrated.

  FIG. 12 shows that when the set value of the distance between the axial road surfaces is kept constant at the distance between the axial road surfaces when the tire model is stationary and a constant load is applied to the tire model, the tire model receives from the road surface model. It is a graph which shows reaction force for every rotation angle of a tire model. If the rolling analysis is performed with the set value of the axial road surface distance h kept constant at the axial road surface distance h when the tire model 61 is stationary, a constant load is applied to the tire model 61 Even so, as shown in FIG. 12, the reaction force RF that the tire model 61 receives from the road surface model 62 decreases between the rotation angle 0 ° and 25 ° of the tire model 61. This is because when the tire model 61 rolls, the rigidity of the tire model 61 decreases. In this case, it can be reproduced that the tire model 61 receives the desired reaction force RF from the road surface model 62 immediately after the start of the rolling analysis. However, when the tire model 61 rolls, it cannot be reproduced that the tire model 61 receives the desired reaction force RF from the road surface model 62. As a result, in this case, there is a possibility that various physical quantities of the tire cannot be accurately calculated.

  FIG. 13 shows the rotational angle of the tire model when the tire model keeps the set value of the distance between the road surfaces constant at a constant value and the tire model applies a reaction force received from the road surface model when a constant load is applied to the tire model. It is a graph shown for every. However, the vibration characteristic evaluation apparatus 30 according to the present embodiment first rolls the tire model 61 without setting the axial road surface distance h to a constant value, and when the axial road surface distance h becomes steady, the steady-state shaft. The rolling analysis is performed with the value of the distance h between the road surfaces as a constant set value. The value of the axial road surface distance h at a constant time is the distance between the axial road surfaces after the rigidity of the tire model 61 is lowered. Therefore, the vibration characteristic evaluation device 30 can reproduce that the tire model 61 receives the desired reaction force RF from the road surface model 62 as shown in FIG. As a result, the vibration characteristic evaluation device 30 can more accurately calculate various physical quantities of the tire 10 shown in FIG.

  As described above, the pneumatic tire anti-leakage performance simulation test method, the pneumatic tire anti-leakage performance simulation computer program, and the pneumatic tire anti-leakage performance simulation test apparatus according to the present invention include the pneumatic tire. It is useful for testing the air leak resistance performance of the pneumatic tire, and is particularly suitable for reducing the time required for the air leak resistance test of the pneumatic tire.

DESCRIPTION OF SYMBOLS 10 Tire 11 Cap tread 11a Tread surface 11b Block 12 Groove 12a Vertical groove 12b Horizontal groove 13 Under tread 14 Side tread 15 Belt 16 Carcass 17 Bead 18 Bead filler 30 Vibration characteristic evaluation apparatus 31 Memory | storage part 32 I / O port 40 Processing part 41 Model preparation part 42 tire mounting portion 43 rolling analysis portion 44 contact reaction force analysis portion 50 terminal device 51 input device 52 display device 61 tire model 62 road surface model 63 wheel model

Claims (11)

A friction coefficient is set between a tire model representing a tire and a road surface model representing a road surface in contact with the tire,
Applying a predetermined load to the tire model to contact the road surface model;
Rolling the tire model until a predetermined condition is satisfied while keeping the load constant;
The distance between the axis road surface between the rolling axis of the tire model and the road surface model after the predetermined condition is satisfied,
A tire simulation test method, wherein a physical quantity is calculated by performing rolling analysis while keeping the distance between the axial road surfaces constant at the set value.   Each time the tire model rolls and moves a predetermined amount, an average value of the distance between the axial road surfaces while the tire model rolls and moves a predetermined amount is calculated, and the average value calculated a plurality of times is calculated. The tire simulation test method according to claim 1, wherein when the difference between two average values adjacent to each other is equal to or less than a threshold value, it is determined that the predetermined condition is satisfied.   The tire simulation test method according to claim 1, wherein the predetermined condition is determined to be satisfied when a distance traveled by the tire model after the tire model starts rolling exceeds a threshold value.   4. The tire simulation test method according to claim 3, wherein the threshold value is a value equal to or greater than a contact length of the tire model.   The said set value is an average value of the distance between the axial road surfaces while the tire model rolls and moves by a predetermined amount after the predetermined condition is satisfied. The tire simulation test method according to claim 1.   The tire simulation test method according to any one of claims 1 to 5, wherein the physical quantity is calculated while the tire model rolls for a distance of one pitch or more of a pattern formed on the tire.   The tire simulation test according to any one of claims 1 to 5, wherein the physical quantity is calculated each time the tire model rolls by a distance equal to or less than a quarter pitch of a pattern formed on the tire. Method.   The tire rolling test method according to claim 1, wherein the rolling analysis is a quasi-static analysis.   The tire simulation test method according to any one of claims 1 to 8, wherein the tire model freely rolls with a relative displacement between the tire model and the road surface model.   A computer program for tire simulation, which causes a computer to execute the tire simulation test method according to any one of claims 1 to 9. A storage unit for storing the computer program for tire simulation according to claim 10;
A processing unit for acquiring the tire simulation computer program from the storage unit and executing the tire simulation computer program;
A tire simulation test apparatus comprising:

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