JP4372498B2 - Tire performance prediction method, tire performance prediction computer program, and tire / wheel model creation method - Google Patents

Description

The present invention relates to a tire performance simulation, and more particularly, a tire performance prediction method, a tire performance prediction computer program, and a tire / wheel that can predict tire performance efficiently while ensuring calculation accuracy. The purpose is to provide a model creation method .

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

  In recent years, in order to obtain a more accurate prediction result, a tire performance simulation method for predicting various performances of a tire with the tire mounted on a wheel is being used. As such a tire performance prediction method, for example, Patent Document 1 discloses a simulation method including a step of fitting a bead portion of a tire to a rim of a wheel after narrowing the tire bead width.

JP 2002-350294 A

  However, in the tire simulation method disclosed in Patent Document 1, in order to simulate a more realistic state, a step of narrowing the bead portion of the tire below the rim width and a step of fitting the bead portion to the rim Including. Due to this, the tire simulation method disclosed in Patent Document 1 has a problem that the calculation time becomes long.

Accordingly, the present invention has been made in view of the above, and a tire performance prediction method and a tire performance prediction computer program capable of efficiently predicting tire performance while ensuring calculation accuracy. And a method of creating a tire / wheel model.

  In order to achieve the above-described object, a tire performance prediction method according to the present invention is configured to predict the performance of a tire fitted to a wheel rim, and the tire and the two rims included in the wheel. The bead portion by dividing the width of the rim model wider than the width of the bead portion of the tire model by creating a tire model and a rim model. A fitting step for fitting to the rim model; and a restraining step for matching translational freedom in the width direction of the tire model of both rims of the rim model.

  Further, the computer program for predicting tire performance according to the present invention described below includes a plurality of the tire and the two rims included in the wheel in predicting the performance of the tire fitted to the rim of the wheel. The bead portion is fitted to the rim model by narrowing the width of the rim model wider than the bead portion of the tire model by creating a tire model and a rim model by dividing into small elements. A fitting procedure to be combined, a restraining procedure for matching the degrees of freedom of translation in the width direction of the tire model of both rims of the rim model, and a computer are executed.

  This method for predicting tire performance eliminates the need to temporarily narrow the bead portion of the tire model. Thereby, since the movement of the bead part when the rim and the bead part are fitted can be reduced, it is possible to prevent the bead part from rapidly fitting to the rim when the internal pressure P is applied after the fitting. As a result, since the vibration of the tire when the rim and the bead part are fitted can be reduced, the damping time of the vibration can be shortened and the calculation time can be shortened. As a result, the tire performance can be predicted more efficiently while ensuring the calculation accuracy. According to the computer program for predicting tire performance according to the present invention, the above-described method for predicting tire performance can be realized using a computer.

  Further, the tire performance prediction method according to the present invention is the tire performance prediction method, wherein the tire model is either during the fitting step or during the restraint step, or between the fitting step and the restraint step. It is characterized by loading an internal pressure.

  Further, the following computer program for predicting tire performance according to the present invention is the computer program for predicting tire performance in the fitting procedure, during the restraint procedure, or between the fitting procedure and the restraint procedure. An internal pressure is applied to the tire model.

  In this tire performance prediction method, the procedure of the internal pressure load can be advanced simultaneously with the fitting of the rim and the like, so that the calculation time can be shortened accordingly. According to the computer program for predicting tire performance according to the present invention, the above-described method for predicting tire performance can be realized using a computer.

  The tire performance prediction method according to the present invention is characterized in that, in the tire performance prediction method, at least one of the two rims constituting the rim model is modeled as a rigid body.

  The following computer program for predicting tire performance according to the present invention is characterized in that, in the computer program for predicting tire performance, at least one of two rims constituting the rim model is modeled as a rigid body. To do.

  In this tire performance prediction method, the rim of the wheel is modeled as a rim instead of a deformed body. Thereby, since the time increment value in the Courant condition does not decrease, an increase in calculation time can be suppressed. According to the computer program for predicting tire performance according to the present invention, the above-described method for predicting tire performance can be realized using a computer.

  In the tire performance prediction method according to the present invention, the friction coefficient between the rim model and the bead portion after the bead portion is fitted to the rim model in the tire performance prediction method is calculated using the rim model. The coefficient of friction is larger than the friction coefficient when the bead portion is fitted.

  The following computer program for predicting tire performance according to the present invention is the computer program for predicting tire performance, wherein the coefficient of friction between the rim model and the bead portion after the bead portion is fitted to the rim model. Is made larger than the friction coefficient when the bead portion is fitted to the rim model.

  In this way, the state of the tire and the rim portion of the wheel during fitting can be reproduced more accurately. Thereby, it is possible to prevent the prediction of the performance of the tire or the tire / wheel assembly in a poorly fitted state, and to improve the prediction accuracy. According to the computer program for predicting tire performance according to the present invention, the above-described method for predicting tire performance can be realized using a computer.

  Further, as in the tire performance prediction method according to the present invention, the friction coefficient after fitting the bead portion to the rim model is 0.50 or more and 2.00 or less, and the rim model includes the bead. The friction coefficient when fitting the parts is preferably 0.01 or more and 0.40 or less.

  Further, the tire performance prediction method according to the present invention is characterized in that, in the tire performance prediction method, when the rim model is fitted to the bead portion, the rim model is replaced with an integrated rim model. And

  Further, the following computer program for predicting tire performance according to the present invention provides an integrated rim model in which both rims are integrated when the rim model is fitted to the bead portion in the computer program for predicting tire performance. It is characterized by replacing.

  If the two rims included in the rim model are replaced with the integrated rim model as in the tire performance prediction method, it is not necessary to provide constraint conditions for both rims, and the calculation algorithm can be simplified. According to the computer program for predicting tire performance according to the present invention, the above-described method for predicting tire performance can be realized using a computer.

Further, the tire performance prediction method according to the present invention is the tire performance prediction method according to the tire performance prediction method, in the model creation step, the nodes of the microelements on the surface of the rim model and the tire in contact with the surface of the rim model. It is characterized by sharing the nodes of minute elements on the surface of the bead part of the model.

Further, the following computer program for predicting tire performance according to the present invention is the computer program for predicting tire performance, wherein in the model creation procedure, the nodes of minute elements on the surface of the rim model, the surface of the rim model, It shares the node of the microelement on the surface of the bead portion of the tire model that comes into contact.

  In this tire performance prediction method, the nodes on the surface of the rim model and the nodes on the bead surface of the tire model are shared. Thereby, since the model of a bead part and a rim can be simplified, calculation time can be shortened. As a result, tire performance can be predicted more efficiently while ensuring calculation accuracy. According to the computer program for predicting tire performance according to the present invention, the above-described method for predicting tire performance can be realized using a computer.

In addition, the following method for creating a tire / wheel model according to the present invention provides a tire / wheel assembly model used for predicting the performance of a tire fitted to a rim of a wheel. A model creation process for creating a tire model and a rim model by dividing the two rims included in the wheel into a plurality of minute elements, and a width of the rim model that is wider than the width of the bead portion of the tire model. A fitting step of fitting the bead portion to the rim model by narrowing, and a restraining step of matching the degree of freedom of translation in the width direction of the tire model of both rims of the rim model. .

If various performances of the tire are predicted using the tire / wheel model created by the tire / wheel model creation method, a procedure for once narrowing the bead portion of the tire model becomes unnecessary. Thereby, since the movement of the bead part when the rim and the bead part are fitted can be reduced, it is possible to prevent the bead part from rapidly fitting to the rim when the internal pressure P is applied after the fitting. As a result, since the vibration of the tire when the rim and the bead part are fitted can be reduced, the damping time of the vibration can be shortened and the calculation time can be shortened. As a result, the tire performance can be predicted more efficiently while ensuring the calculation accuracy.

Further, the following tire / wheel model creation method according to the present invention is the tire / wheel model creation method, wherein in the model creation step, the nodes of the microelements on the surface of the rim model, the surface of the rim model, It shares the node of the microelement on the surface of the bead portion of the tire model that comes into contact .

In this tire / wheel model creation method , the nodes on the surface of the rim model and the nodes on the bead surface of the tire model are shared. Thereby, since the model of a bead part and a rim can be simplified, calculation time can be shortened. As a result, if the tire performance is predicted using the tire / wheel model created by this tire / wheel model creation method , the tire performance can be predicted more efficiently while ensuring the calculation accuracy. it can.

The tire / wheel model creation method according to the present invention is characterized in that, in the tire / wheel model creation method , at least one of two rims constituting the rim model is modeled as a rigid body. To do.

In this tire / wheel model creation method , the wheel rim is modeled as a rigid body, not as a deformable body. As a result, the time increment value under the Courant condition does not decrease, so if the tire performance is predicted using the tire / wheel model created by this tire / wheel model creation method, the increase in calculation time can be suppressed. Can do.

  According to the present invention, since the movement of the bead portion when the rim and the bead portion are fitted can be reduced, the vibration of the tire when the rim and the bead portion are fitted can be reduced. Thereby, the decay time of the vibration can be shortened and the calculation time can be shortened.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. 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 any type of tire, but is particularly suitable for predicting the performance of a pneumatic tire.

(Embodiment 1)
The tire performance prediction method according to the first embodiment of the present invention is characterized by the following points. That is, the rim width of the wheel rim model modeled based on the finite element method or the like is made larger than the width of the bead portion of the tire model, and then the rim model is fitted to the bead portion of the tire model. Thereafter, the translational freedom in the width direction of the tire model is matched between both rims of the rim model, and various performances of the tire mounted on the wheel and the tire / wheel assembly are predicted. Note that the tire performance prediction method according to the first embodiment of the present invention can be realized by simulation using a computer.

  If the process itself of attaching a tire to a wheel is predicted, a simulation method having two steps of narrowing the tire bead width and fitting step as disclosed in Patent Document 1 is required. . Here, when fitting the bead portion of the tire to the rim of the wheel, vibration is generated in each portion of the tire. Therefore, it is necessary to wait until this vibration is attenuated when shifting to a tire rolling or other simulation after mounting the tire on the wheel.

  As described above, in the simulation method according to Patent Document 1, two steps are required to obtain a tire / wheel assembly, and it is necessary to wait for the vibration of each part of the tire generated during fitting to be attenuated. For this reason, it takes a long calculation time to complete rolling and other simulations of tires and the like mounted on the wheels. However, when a tire is mounted on a wheel and various performances of the tire or the like in a state where the tire is actually used are predicted, the above two steps are not necessarily required. The present inventors focused on this point and decided to predict various performances of the tire or tire / wheel assembly mounted on the wheel by the following procedure.

  FIGS. 1-1 and 1-2 are explanatory diagrams illustrating an outline of a tire performance prediction method according to the first embodiment of the present invention. 1-3 is explanatory drawing which shows each axis | shaft of a tire model and a wheel model. FIG. 2 is a flowchart showing a tire performance prediction method according to the embodiment of the present invention. The procedure of the tire performance prediction method according to the present invention will be described based on these drawings.

  In the tire simulation method according to the first embodiment of the present invention, a finite element method (FEM) is used as an analysis method for predicting characteristics of a tire or a tire / wheel assembly. An analysis method applicable to the tire simulation method according to the present invention 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. The most appropriate analysis method can be selected depending on the tire, tire / wheel assembly, boundary condition, or the like that is the performance prediction target, or a plurality of analysis methods can be used in combination. The present invention is particularly suitable for predicting various performances of a tire by an explicit method using a finite element method.

  FIG. 3A is a perspective view illustrating an example in which a tire is divided into minute elements. FIG. 3-2 is a perspective view illustrating an example in which the wheel is divided into minute elements. FIG. 3-3 is a perspective view illustrating an example of a tire / wheel model divided into minute elements. In executing the tire simulation method according to the present embodiment of the present invention, first, a model suitable for each analysis method is created so as to be analyzed by an analysis method such as a finite element method (step S101).

For example, when the finite element method is used, the tire and the wheel are divided into a finite number of microelements 1 ₁ , 1 ₂ , 1 _n , 3 ₁ , 3 ₂ , 3 _{n and the} like based on the finite element method. Thereby, the finite element model of a tire and a wheel, that is, the tire model 1 and the wheel model 3 can be created. Then, the tire model 1 is mounted on the wheel model 3 by the tire performance prediction method according to the present invention to obtain the tire / wheel model 100 shown in FIG. By executing a simulation such as rolling on the tire / wheel model 100, various performances of the tire in a state where the tire is mounted on the wheel and various performances as a tire / wheel assembly are predicted. Here, the tire performance includes various performances that can be handled by dynamic simulation of the tire, such as braking performance, running performance on a wet road surface, cornering performance, and the like.

  The microelements based on the finite element method are, 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, and a rectangular shell. It is desirable to use an element that can be used by a computer, such as a shell element. The microelements divided in this way are identified one by one using the three-dimensional coordinates in the process of analysis.

  Next, as shown in FIG. 1-1, a rim model 10 is set in which the rim width J2 of the two rims 11 and 12 is wider than the normal rim width J1 of the wheel (step S102). The method for creating the rim model 10 is the same as the method for creating the wheel model 3 described above. Note that, when the wheel model 3 is created, the rim width J2 of the rim model 10 may be set in advance larger than the normal rim width J1. Further, in FIG. 3-2, the entire wheel is modeled to include the rim model 10, but it is not always necessary to model the entire wheel. A rim model in which only the rims 11 and 12 are modeled is shown. It may be used. Further, the rim model 10 only needs to be modeled based on the finite element method or the like, for example, only in the range covering the bead portion 2 of the tire model 1, and it is not necessary to model the entire rim model 10.

  Here, the rim width refers to the maximum width between the rims 11 and 12 inside the rims 11 and 12 of the wheel. Further, the width of the bead portion means the maximum width at a portion where both bead portions of the tire are fitted to the rim. In the tire performance prediction method of the present invention, the rim width of the wheel is changed before and after the tire model 1 is mounted on the wheel model 3, and therefore the rim width and bead width change during this time.

  Further, the rim model 10 applicable to the present invention can be configured as a deformed body as a whole. That is, the rim model 10 can be configured in consideration of the elastic modulus and deformation of the rims 11 and 12 throughout the rim model 10. Further, the rim model 10 may be modeled as a rigid body instead of a deformable body. This is advantageous in the following points.

  In the explicit method of the finite element method, it is necessary to satisfy the Courant condition. In general, a wheel is made of an aluminum alloy, iron, or the like, and its elastic modulus is high. In general, since the wheel has a complicated shape, it is necessary to reduce the size of each minute element in order to accurately analyze this by the finite element method. For this reason, when the wheel rims 11 and 12 are converted into rim models, the time increment value tends to be small in order to satisfy the Courant condition, and a long time is required for calculation. Here, if the wheel rims 11 and 12 are modeled as rigid bodies rather than deformed bodies, it is not necessary to consider the elastic modulus and the size of the minute elements to be divided. As a result, since the time increment value does not decrease, an increase in calculation time can be suppressed.

  4A, 4B, and 4C are explanatory diagrams illustrating a rim model in which left and right are separated. In the case of the rim model 10 in which both rims 11 and 12 are separate bodies, both rims 11 and 12 may be handled as rigid bodies or deformed bodies, but the present invention is not limited to this. For example, as illustrated in FIG. 4A, for example, one rim 11 may be a rigid body and the other rim 12 may be a deformed body. In this case, after narrowing the rim width J2 to the regular rim width J1 (see FIG. 4-3), it is preferable to integrate the rim 12 handled as a deformed body with the rim 11 handled as a rigid body. Thus, by treating one rim as a rigid body and the other rim as a deformed body, the calculation algorithm can be simplified as compared with the case where both rims are handled as a rigid body.

  Both rims 11 and 12 of the rim model 10 created in step S102 are independent only in the degree of translational freedom in the width direction (Z direction in FIGS. 1-1 to 1-3) of the tire model 1, and the remaining degrees of freedom. Keep them consistent. That is, the rotational and translational degrees of freedom around the X axis of the tire model 1, the rotational and translational degrees of freedom around the Y axis, and the rotational degrees of freedom around the Z axis are matched. Here, the Z axis is the rotation axis of the tire model 1 and the wheel model 3, and the X axis is the rolling direction of the tire model 1 and the wheel model 3. The Y axis is an axis perpendicular to the Z axis and the X axis.

Next, as shown in FIG. 1-2, the rotation axis of the rim model 10 and the rotation axis of the tire model 1 are made to coincide with each other, the rim width of the rim model 10 is narrowed to the regular rim width J1, and the bead portion of the tire model 1 is 2 is fitted to the rims 11 and 12, and the tire model 1 is mounted on the wheel model 3 (step S103). At this time, W ₂ of the bead width portion of the tire model 1 is narrowed to W ₁ and becomes the width of the bead portion with respect to the normal rim width J ₁ .

  Thereafter, the translational freedom in the width direction of the tire model 1 is matched between the rim 11 and the rim 12 (step S104). FIGS. 5A and 5B are explanatory diagrams illustrating an example of a method for matching the translational degrees of freedom. In order to make the translational degrees of freedom coincide, for example, there is a method in which a constraint condition is provided between the rims 11 and 12 to express the behavior of the integrated rim. Further, as shown in FIG. 5B, after the rims 11 and 12 are narrowed to the regular rim width J1 and the rims 11 and 12 and the bead portion 2 of the tire model 1 are fitted together, 12 may be replaced with an integrated rim model 10a. Replacement to the integrated rim model 10a can be realized, for example, by changing to the integrated rim model 10a at a timing when the rim model 10 contacts the bead portion 2 of the tire model 1. As described above, if the integrated rim model 10a is replaced, it is not necessary to provide the constraint conditions for both the rims 11 and 12, so that the calculation algorithm can be simplified.

  By such a method, in the performance evaluation in a state where the rim model 10 is assembled to the tire model 1, it is possible to handle both the rims 11 and 12 as one rim. Further, the procedure for matching the translational degrees of freedom ends instantaneously in the computer simulation, so that the calculation time does not increase. As a result, compared with the simulation method disclosed in Patent Document 1, the tire model 1 is mounted on the wheel model 3 until the prediction of the performance of the tire or the performance of the tire / wheel assembly is completed. The calculation time can be shortened.

  When evaluating various performances of the tire, it is necessary to apply an internal pressure P to the tire. The internal pressure P can be applied at any step when the rim width of the rim model 10 is narrowed to the normal rim width J1 or when the translational degree of freedom is matched between the rim 11 and the rim 12. Alternatively, it is possible to apply a load while narrowing the rim width and matching the translational degrees of freedom. As a result, the step of the internal pressure load can be advanced simultaneously with the fitting of the rim, etc., so that the calculation time can be shortened accordingly. The internal pressure P may be applied after the rim width of the rim model 10 is narrowed to the normal rim width J1 or after the translational degree of freedom is matched between the rim 11 and the rim 12.

  In the present invention, the rims 11 and 12 and the bead portion 2 are fitted while the rim width of the rim model 10 is narrowed to the regular rim width J1. That is, unlike the simulation method disclosed in Patent Document 1 in which the bead portion 2 is once narrowed and then fitted to the rims 11 and 12, a procedure for once narrowing the bead portion 2 is not necessary. Accordingly, the movement of the bead part 2 when the rims 11 and 12 and the bead part 2 are fitted can be reduced. Therefore, when the internal pressure P is applied after the fitting, the bead part 2 is abruptly applied to the rims 11 and 12. Can be prevented from being fitted. As a result, since the vibration of the tire when the rims 11 and 12 and the bead portion 2 are fitted can be reduced, the vibration attenuation time can be shortened and the calculation time can be shortened. After obtaining the state where the tire model 1 is mounted on the wheel model 3 by the above procedures, give a predetermined load F, speed, slip angle, camber angle, slip ratio, lateral force, longitudinal force, and other traveling conditions, Various performances of the tire are predicted (step S105).

  FIGS. 6A and 6B are device configuration diagrams illustrating the tire performance prediction device according to the present invention in the first embodiment. As illustrated in FIG. 6A, the tire performance prediction device 50 includes a processing unit 52 and a storage unit 54. Further, an input / output device 51 is connected to the tire performance prediction device 50, and the physical property value of the rubber, the physical property value of the wheel constituting the tire model 1 or the prediction calculation is provided by the input means 53 provided therein. The boundary condition, the traveling condition, etc. are input to the processing unit 52 and the storage unit 54. Here, an input device such as a keyboard and a mouse can be used for the input means 53. Further, as shown in FIG. 6B, the processing unit 52 fits the rim model to the bead portion of the tire model and the model creation unit 52m that creates the tire model and the rim model, and matches the translational degrees of freedom of both rims. It has a fitting / restraining portion 52s and an analysis portion 52p that predicts the performance of the tire or the like using the obtained tire / wheel model.

  The storage unit 54 stores a computer program including the tire performance prediction method. Here, the storage unit 54 is a hard disk device, a magneto-optical disk device, a non-volatile memory such as a flash memory (a storage medium that can be read only such as a CD-ROM), or a RAM (Random Access Memory). Such a volatile memory or a combination thereof can be used.

  Moreover, the said computer program may be what can implement | achieve the tire performance prediction method which concerns on this invention by the combination with the computer program already recorded on the computer system. In addition, a computer program for realizing the functions of the model creation unit 52m, the fitting / restraining unit 52s, and the analysis unit 52p constituting the processing unit 52 is recorded on a computer-readable recording medium and recorded on the recording medium. The tire performance prediction method according to the present invention may be executed by causing the computer system to read and execute the program. The “computer system” here includes an OS and hardware such as peripheral devices.

  The processing unit 52 includes a memory and a CPU. At the time of prediction of tire performance, based on the set tire model and input data, the processing unit 52 reads the program into a memory incorporated in the processing unit 52 and performs calculation. At that time, the processing unit 52 appropriately stores the numerical value in the middle of the calculation in the storage unit 54, and advances the calculation by taking out the stored numerical value. The processing unit 52 may realize the functions of the model creation unit 52m, the fitting / restraining unit 52s, and the analysis unit 52p with dedicated hardware instead of the computer program. The prediction result is displayed on the display means 55 of the input / output device.

  Here, a CRT (Cathode Ray Tube), a liquid crystal display device or the like can be used for the display means 55. The prediction result can also be output to a printer provided as necessary. The storage unit 54 may be built in the processing unit 52 or may be in another device (for example, a database server). As described above, the tire performance prediction device 50 may access the processing unit 52 and the storage unit 54 by communication from the terminal device including the input / output device 51.

  As described above, according to the tire performance prediction method of the first embodiment of the present invention, the procedure for once narrowing the bead portion of the tire model becomes unnecessary. Thereby, since the movement of the bead part when the rim and the bead part are fitted can be reduced, it is possible to prevent the bead part from rapidly fitting to the rim when the internal pressure P is applied after the fitting. As a result, since the vibration of the tire when the rim and the bead part are fitted can be reduced, the damping time of the vibration can be shortened and the calculation time can be shortened. As a result, the tire performance can be predicted more efficiently while ensuring the calculation accuracy. Note that the configuration of the present invention described in Embodiment 1 can be applied as appropriate in the following embodiments.

(Embodiment 2)
FIGS. 7-1 and FIGS. 7-2 are explanatory drawings showing a tire performance prediction method according to the present invention of Embodiment 2. FIGS. The tire performance prediction method has substantially the same configuration as the tire performance prediction method according to the first embodiment, but the tire performance with high bead rigidity and the performance of the tire and wheel assembly are as follows. In the prediction, a tire model and a rim model are provided separately, and a tire / wheel model that considers contact between the bead portion model and the rim model is used. Since other configurations are the same as those of the first and second embodiments, the description thereof is omitted and the same components are denoted by the same reference numerals.

  As shown in FIG. 7A, in the tire / wheel model 101, the bead portion 2 of the tire model 1 and the rim model 10b are provided separately. The tire model 1 is a model of a tire having a high rigidity of the bead portion 2, for example, a passenger car tire or a truck / bus tire having a flatness ratio of 55% or less. As described above, in the case of a tire having a high bead portion rigidity, if the nodes of the rims 11 and 12 and the bead portion 2 are shared, the bead portion 2 is over-constrained and affects the behavior of the entire tire model 1. The accuracy cannot be secured sufficiently. In addition, when predicting the performance as an assembly of a tire and a wheel, if the joint between the bead part 2 and the rims 11 and 12 is shared regardless of the rigidity of the bead part of the tire, the contact between the two cannot be considered. The performance as a tire / wheel assembly cannot be fully reproduced.

  Therefore, when predicting the performance of a tire having a high bead portion rigidity or the performance of an assembly of a tire and a wheel, the bead portion 2 of the tire model 1 and the rim model 10b, as in the tire / wheel model 102, Are provided separately. In this way, over-constraint of the bead portion 2 can be avoided, so that the behavior of the entire tire is not affected, and sufficient calculation accuracy can be ensured.

  When the bead part 2 and the rim model 10b of the tire model 1 are set separately, the position of the rim model 10b before fitting the rims 11 and 12 to the bead part 2 is as shown in FIG. Is preferably set at a position where it does not penetrate into the rim model 10b. Then, as shown in FIG. 7-2, both rims 11 and 12 of the rim model 10b are narrowed to the regular rim width J1, and the rims 11 and 12 and the bead portion 2 are fitted.

  In the simulation method disclosed in Patent Document 1, since the bead portion is once narrower than the rim width and fitted to the rim, a large vibration is generated at the time of fitting to the rim until the vibration converges. The calculation could not proceed. However, according to the present invention according to the second embodiment described above, since the vibration of the tire when the bead portion 2 is fitted to the rims 11 and 12 can be minimized, the simulation disclosed in Patent Document 1 Compared with the method, the calculation time can be greatly reduced.

  When the contact between the rims 11 and 12 and the bead portion 2 is taken into consideration, it is preferable that the coefficient of friction μ between the rims 11 and 12 is larger after fitting than during fitting. For example, in the state during fitting shown in FIG. 7A, the friction coefficient μ is set to 0.01 or more and 0.40 or less, and the tire model 1 is attached to the wheel model 32 after fitting shown in FIG. After that, the friction coefficient μ is set to 0.50 or more and 2.00 or less. In this way, the state of the tire and the rim portion of the wheel during fitting can be reproduced more accurately. Thereby, it is possible to prevent the prediction of the performance of the tire or the tire / wheel assembly in a poorly fitted state, and to improve the prediction accuracy. It is preferable that both the static friction coefficient and the dynamic friction coefficient are in the range of the friction coefficient μ.

  As mentioned above, in this invention which concerns on Embodiment 2, when estimating the performance as an assembly of a tire and a wheel, the bead part of a tire model and a rim model can be set up separately. As a result, it is possible to avoid over-constraining the bead portion, so that the behavior of the entire tire is not affected, and sufficient calculation accuracy can be ensured. In addition, considering the contact between the bead portion and the rim, the friction coefficient after fitting is set to be larger than that during fitting, so that the state of the tire and wheel rim portion during fitting can be more accurately determined. Can be reproduced. As a result, it is possible to avoid predicting the performance of a tire or the like in a poorly fitted state, and therefore it is possible to improve the prediction accuracy of the tire performance. As a result, the tire performance can be predicted more efficiently while ensuring the calculation accuracy.

(Embodiment 3)
FIG. 8 is an explanatory diagram showing a tire performance prediction method according to the present invention in the third embodiment. FIGS. 9-1 and FIGS. 9-2 are explanatory diagrams illustrating a procedure of a tire performance prediction method according to the present invention of Embodiment 3. FIGS. The tire performance prediction method has substantially the same configuration as the tire performance prediction method according to the first embodiment. However, when predicting the performance of a tire having low bead portion rigidity, the tire model bead portion The difference is that a tire / wheel model that shares the nodes of minute elements with the rim model is used. Since other configurations are the same as those of the first embodiment, the description thereof is omitted and the same components are denoted by the same reference numerals.

  As shown in FIG. 8, in the tire / wheel model 102, nodes a1, a2, an on the surface of the rim model 10c in contact with the bead portion 2c of the tire model 1c, and nodes a1, a2, an on the surface of the bead portion 2c Is shared. The tire model 1c is a model of a tire with a low rigidity of the bead portion 2c, such as a tire for a passenger car having a flatness ratio of 60% or more.

  Thus, in the case of a tire having a low bead portion rigidity, even if the nodes of the rims 11 and 12 and the bead portion 2c are shared, the bead portion 2 is not over-constrained and affects the behavior of the entire tire. Since there is almost no calculation accuracy, sufficient calculation accuracy can be secured. On the other hand, in such a tire / wheel model 102, it is not necessary to consider the contact between the rims 11 and 12 and the bead portion 2. Moreover, since the model of the bead part 2c and the rim | limbs 11 and 12 can be simplified, calculation time can be shortened. Furthermore, if the nodes of minute elements are shared, the degree of freedom can be reduced accordingly, so that the calculation speed can be increased.

  When the tire / wheel model 102 sharing the nodes of the minute elements is obtained (FIG. 9-1), the rim width J2 is changed to the regular rim width J1 (FIG. 9-2). As a result, the bead width of the tire model 1c is changed from W2 to W1. Then, the translational degrees of freedom (tire width direction) of both rims 11 and 12 of the rim model 10c included in the tire / wheel model 102 are matched to predict various performances of the tire. Here, the change of the rim width J2 includes both a case of narrowing and a case of widening.

  As described above, in the present invention according to the third embodiment, the nodes of the minute elements in the rim model and the bead portion of the tire model are shared. Thereby, since the model of a bead part and a rim can be simplified, calculation time can be shortened.

(Example)
A tire having the size shown in Table 1 was mounted on a rim, and the longitudinal spring performance of the tire was predicted under the conditions of an internal pressure P = 200 kPa and a load F = 4.0 kN, and a calculation time and a longitudinal spring coefficient K were obtained. The evaluation results of Example 1 and Comparative Example 1 are shown in Table 2, and the evaluation results of Example 2 and Comparative Example 2 are shown in Table 3. The evaluation result is displayed as an index, the calculation time is an index with the conventional examples 1 and 2 as 100, and the longitudinal spring coefficient K is an index with the measured area as 100. If the longitudinal spring coefficient is 90 to 110, there is no practical problem. Details of the prediction methods of Examples 1x to 2z and Comparative Examples 1 and 2 shown in Tables 2 and 3 are as follows.

  In Examples 1x and 2x, the wheel is a rigid body model in which only the rim portion is modeled, and nodes are shared at the contact portion between the rim model and the tire model. In Examples 1y and 2y, the wheel is a rigid body model in which only the rim portion is modeled, and the contact between the rim model and the tire model is taken into consideration. The coefficient of friction during mounting the tire model on the rim model is 0.1, and the coefficient of friction after mounting is 1.0. In Examples 1z and 2z, the wheel is a full model of a deformed body, and the contact between the rim model and the tire model is taken into consideration. The coefficient of friction during mounting the tire model on the rim model is 0.1, and the coefficient of friction after mounting is 1.0. In Comparative Examples 1 and 2, the wheel is a full model of the deformed body, and after the bead width of the tire model is narrower than the rim width of the rim model, the internal pressure is applied in consideration of contact between the tire model and the rim model. Fit. That is, Comparative Examples 1 and 2 are methods disclosed in Patent Document 1.

  From Tables 2 and 3, it can be seen that according to the present invention, the longitudinal spring coefficient falls within a practically acceptable range in any of the examples. Moreover, it turns out that calculation time becomes quicker than the comparative examples 1 and 2. In Examples 1x and 2x sharing the nodes of the rim and the bead portion, the calculation time is the fastest, and is less than half that of Comparative Examples 1 and 2. In Examples 1y and 2y in which only the rim portion is modeled as a rigid body and the contact between the rim and the bead portion is considered, the calculation speed is less than half that of Comparative Examples 1 and 2, and the calculation accuracy is close to the actually measured value. Become. As described above, in the embodiments 1y and 2y, the calculation speed can be improved without sacrificing the calculation accuracy. In Examples 1z and 2z in which the entire wheel is a deformed body and the contact between the rim and the bead portion is considered, the calculation speed is faster than that of Comparative Examples 1 and 2, and the calculation accuracy is close to the actual measurement value.

As described above, the tire performance prediction method, the tire performance prediction computer program, and the tire / wheel model creation method according to the present invention are useful for predicting various performances of a tire mounted on a wheel, In particular, it is suitable for efficiently predicting tire performance while ensuring calculation accuracy.

It is explanatory drawing which shows the outline | summary of the prediction method of the tire performance which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the outline | summary of the simulation method of the tire which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows each axis | shaft of a tire model and a wheel model. It is a flowchart which shows the prediction method of the tire performance which concerns on embodiment of this invention. It is a perspective view which shows the example which divided | segmented the tire into the microelement. FIG. 3-2 is a perspective view illustrating an example in which the wheel is divided into minute elements. It is a perspective view which shows an example of the tire / wheel model divided | segmented into the microelement. It is explanatory drawing which shows the rim model which made the left and right a separate body. It is explanatory drawing which shows the rim model which made the left and right a separate body. It is explanatory drawing which shows the rim model which made the left and right a separate body. It is explanatory drawing which shows an example of the method of making a translational freedom degree correspond. It is explanatory drawing which shows an example of the method of making a translational freedom degree correspond. It is an apparatus block diagram which shows the prediction apparatus of the tire performance which concerns on this invention of Embodiment 1. FIG. It is an apparatus block diagram which shows the prediction apparatus of the tire performance which concerns on this invention of Embodiment 1. FIG. It is explanatory drawing which shows the prediction method of the tire performance which concerns on this invention of Embodiment 2. FIG. It is explanatory drawing which shows the prediction method of the tire performance which concerns on this invention of Embodiment 2. FIG. FIG. 10 is an explanatory diagram showing a tire performance prediction method according to the present invention in Embodiment 3. FIG. 10 is an explanatory diagram showing a procedure of a tire performance prediction method according to the present invention in Embodiment 3; FIG. 10 is an explanatory diagram showing a procedure of a tire performance prediction method according to the present invention in Embodiment 3;

Explanation of symbols

1, 1c Tire model 2, 2c Bead part 3 Wheel model 10, 10b, 10c Rim model 10a Integrated rim model 11, 12 Rim 100, 101, 102 Tire / wheel model

Claims (16)

In predicting the performance of a tire fitted to a wheel rim,
A model creating step of creating a tire model and a rim model by dividing the tire and the two rims included in the wheel into a plurality of minute elements;
A fitting step of fitting the bead portion to the rim model by narrowing the width of the rim model that is wider than the width of the bead portion of the tire model;
A constraining step of matching the degree of freedom of translation in the width direction of the tire model of both rims of the rim model;
A method for predicting tire performance, comprising:   The tire performance prediction method according to claim 1, wherein an internal pressure is applied to the tire model during the fitting process, during the restraining process, or between the fitting process and the restraining process.   The tire performance prediction method according to claim 1 or 2, wherein at least one of the two rims constituting the rim model is modeled as a rigid body.   The friction coefficient between the rim model and the bead part after the bead part is fitted to the rim model is made larger than the friction coefficient when the bead part is fitted to the rim model. Item 4. The tire performance prediction method according to any one of Items 1 to 3.   The friction coefficient after fitting the bead portion to the rim model is 0.50 or more and 2.00 or less, and the friction coefficient when fitting the bead portion to the rim model is 0.01 or more and 0.00. The tire performance prediction method according to claim 4, wherein the tire performance is 40 or less.   The tire performance prediction method according to claim 1, wherein when the rim model is fitted to the bead portion, the rim model is replaced with an integrated rim model in which both rims are integrated. The micro model element node on the surface of the rim model and the micro element node on the surface of the bead portion of the tire model in contact with the surface of the rim model are shared in the model creation step. The tire performance prediction method according to any one of 5. In predicting the performance of a tire fitted to a wheel rim,
A model creation procedure for creating a tire model and a rim model by dividing the tire and the two rims included in the wheel into a plurality of minute elements;
A fitting procedure for fitting the bead portion to the rim model by narrowing the width of the rim model that is larger than the width of the bead portion of the tire model;
A restraining procedure for matching the degree of freedom of translation in the width direction of the tire model of both rims of the rim model;
A computer program for predicting tire performance, which causes a computer to execute.   9. The computer program for predicting tire performance according to claim 8, wherein an internal pressure is applied to the tire model during the fitting procedure, during the restraining procedure, or between the fitting procedure and the restraining procedure. .   The computer program for predicting tire performance according to claim 8 or 9, wherein at least one of two rims constituting the rim model is modeled as a rigid body.   The friction coefficient between the rim model and the bead part after the bead part is fitted to the rim model is made larger than the friction coefficient when the bead part is fitted to the rim model. Item 11. A computer program for predicting tire performance according to any one of Items 8 to 10.   The computer program for predicting tire performance according to any one of claims 8 to 11, wherein when the rim model is fitted to the bead portion, the rim model is replaced with an integrated rim model in which both rims are integrated. 9. The model creation procedure shares a node of a microelement on the surface of the rim model and a node of a microelement on the bead surface of the tire model that contacts the surface of the rim model. 12. The computer program for predicting tire performance according to any one of 12 above. In creating a tire / wheel model used to predict the performance of a tire fitted to a wheel rim,
A model creating step of creating a tire model and a rim model by dividing the tire and the two rims included in the wheel into a plurality of minute elements;
A fitting step of fitting the bead portion to the rim model by narrowing the width of the rim model that is wider than the width of the bead portion of the tire model;
A constraining step of matching the degree of freedom of translation in the width direction of the tire model of both rims of the rim model;
A method for creating a tire / wheel model , comprising: In the model creating step, to claim 14, characterized in that share a node of microelements in the surface of the Rimumoderu, a node of the micro elements in the bead area surface of the tire model in contact with the surface of the Rimumoderu A method for creating the described tire / wheel model. The tire / wheel model creation method according to claim 14 or 15, wherein at least one of the two rims constituting the rim model is modeled as a rigid body.

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