JP6536255B2 - Tire simulation method - Google Patents

Description

  The present invention relates to a tire simulation method capable of evaluating uneven wear of a tire more accurately and quickly.

  Uneven wear of a tire is known as a factor that greatly affects tire life, drainage performance, steering stability, vibration, noise and the like. Conventionally, various tire simulation methods for evaluating uneven wear of a tire using a computer have been proposed.

  For example, in Patent Document 1 and Patent Document 2 below, simulation of a tire including a calculation step of calculating the wear performance of the tire model and a correction step of correcting the tire model to reflect the wear based on the wear performance. A method has been proposed.

Unexamined-Japanese-Patent No. 2005-271661 Japanese Patent Application Laid-Open No. 2006-021648

  The tire simulation methods of Patent Document 1 and Patent Document 2 attempt to accurately evaluate uneven wear of the tire by including a correction step. However, in Patent Document 1, the calculation process and the correction process are repeated until the corrected tire model reaches the maximum wear amount. Patent Document 1 and Patent Document 2 also show a simulation method in which the calculation process and the correction process are repeated a predetermined number of times.

  The inventors conducted various experiments. As a result, the uneven wear of the tire greatly progresses at the initial stage of wear, and after reaching a predetermined uneven wear state, the tire is worn substantially uniformly while maintaining the uneven wear state. It turned out that there was a tendency to For this reason, in the simulation method repeated until reaching the maximum wear amount of Patent Document 1, it takes a lot of time to calculate after becoming a predetermined uneven wear state, and it is not possible to quickly evaluate the uneven wear of the tire. The

  Further, in the simulation method of repeating the predetermined number of calculations in Patent Document 1 and Patent Document 2, when the number of repetitions of the calculation process and the correction process is set to be small, the simulation ends before the predetermined uneven wear state. Uneven wear could not be accurately evaluated. On the other hand, when the number of repetitions of the calculation process and the correction process is set to a large number, it takes a lot of time to calculate after reaching the predetermined uneven wear state, and the uneven wear of the tire can not be evaluated quickly. .

  The present invention has been devised in view of the above situation, and based on the determination of the end of the calculation based on the wear performance of at least two evaluation points of the tread portion of the tire model, the uneven wear of the tire is determined. The main purpose is to provide a tire simulation method that can be evaluated accurately and quickly.

  The present invention is a tire simulation method for evaluating the wear performance of a tire using a computer, wherein the computer inputs a tire model including a tread portion to the computer, and the computer calculates the tire model. Running on a predetermined road surface model and calculating the wear performance of the tread portion, and the computer corrects the tread portion of the tire model to a worn state based on the wear performance. Whether the calculation step and the correction step are repeatedly performed or the calculation step and the correction step are ended based on the correction step and the wear performance of the at least two evaluation points of the tread portion by the computer And an end determining step of determining

  In the tire simulation method according to the present invention, the end determination step calculates an approximation of wear performance of the two evaluation points, and determines that the approximation is low based on a predetermined threshold value. In this case, it is preferable to repeat the calculation process and the correction process and to end the calculation process and the correction process when it is determined that the degree of approximation is high.

  In the tire simulation method according to the present invention, it is desirable that the degree of approximation be represented by a difference in wear performance between the two evaluation points or a ratio of wear performance between the two evaluation points.

  In the tire simulation method according to the present invention, the tread portion includes at least one block, and the evaluation point is a first evaluation point defined in advance in the tire rotation direction of the block, and the first evaluation point. It is desirable to include a second evaluation point defined in advance in the rear end side area in the tire rotational direction of the block.

  In the tire simulation method according to the present invention, the tread portion includes at least one block, the block includes an inner region in an axial direction of the tire and an outer region in an axial direction of the tire, and the evaluation point is It is desirable to include a third evaluation point predefined in the inner area of the block and a fourth evaluation point predefined in the outer area of the block.

  In the tire simulation method according to the present invention, the tread portion includes at least one block, and the evaluation point is a fifth evaluation point having the lowest wear performance among the blocks, and the fifth evaluation point among the blocks. It is desirable to include a sixth rating with the highest wear performance.

  In the tire simulation method according to the present invention, it is desirable that wear energy be used as the wear performance of each evaluation point.

  In the tire simulation method according to the present invention, it is desirable that the wear performance at each evaluation point be a unit time wear amount calculated based on the wear energy and the material wear performance of the tread portion.

  According to the tire simulation method of the present invention, it is determined whether the computer repeatedly executes the calculation process and the correction process or ends the calculation process and the correction process based on the wear performance of at least two evaluation points of the tread portion. And an end determination step to be determined. Since such a tire simulation method determines the end based on the wear performance of the two evaluation points, it is possible to accurately and quickly evaluate the partial wear between the two evaluation points.

It is a flowchart which shows the process sequence of the simulation method of the tire of one Embodiment of this invention. It is a tread development view which visualizes and shows a tire model by which wear performance is evaluated. It is the elements on larger scale of the tire model of FIG. It is sectional drawing at the time of completion | finish of simulation of the AA of the block of FIG. It is sectional drawing at the time of completion | finish of simulation of the BB line of the block of FIG. It is sectional drawing of the block at the time of completion | finish of simulation by a comparative example. It is sectional drawing of the block at the time of completion | finish of simulation by other comparative examples.

Hereinafter, an embodiment of the present invention will be described based on the drawings.
The tire simulation method according to the present embodiment (hereinafter sometimes simply referred to as “simulation method”) is a method for reproducing and evaluating the wear performance of a tire using a computer.

  FIG. 1 is a flowchart showing the processing procedure of the simulation method of the present embodiment. In the simulation method of the present embodiment, first, step S1 of inputting the tire model 1 including the tread portion to the computer is performed.

  FIG. 2 is a tread development view visualizing and showing a tire model 1 including a tread portion 2 whose wear performance is evaluated by the simulation method of the present embodiment. In the step S1 of inputting the tire model 1, as shown in FIG. 2, a finite number of small elements F (i) (i = 1, 2, ...) is discretized. Thereby, the tire model 1 in which the tire including the tread portion 2 is three-dimensionally modeled is set. As a numerical analysis method, for example, a finite element method, a finite volume method, a difference method or a boundary element method can be adopted as appropriate, but in the present embodiment, the finite element method is adopted.

  As the element F (i), for example, a tetrahedron solid element, a pentahedron solid element, or a hexahedron solid element is used. Each element F (i) is provided with a plurality of nodes P (j) (j = 1, 2,...). In each of such elements F (i), numerical values such as element numbers, numbers of nodes P (j), coordinate values of nodes P (j) and material characteristics (for example, density, Young's modulus and / or damping coefficient) Data is defined.

  The tread portion 2 of the tire model 1 includes at least one block 3. Each block 3 is divided by a plurality of grooves 4. In the present specification, for easy understanding, the tire model 1 is shown in a schematic form, and for the groove 4, each element F (i) is not displayed.

  As shown in FIG. 1, in the simulation method, next, step S2 of performing initial setting of the tire model 1 and the like is performed. In the initial setting, for example, setting of a road surface model, setting of a boundary condition, application of internal pressure of the tire model 1, and grounding of the tire model 1 with the road surface model are performed.

  The setting of the road surface model is, for example, similar to the tire model 1, based on information on the road surface to be evaluated, to a finite number of elements that can be handled by the numerical analysis method (in the present embodiment, the finite element method) It is discretized. Although it is desirable that the road surface model has a smooth surface, it is provided with fine irregularities such as asphalt road surface, irregular steps, depressions, irregularities similar to the actual traveling road surface such as waviness or wrinkles, etc. It is good.

  For the setting of the boundary condition, for example, the internal pressure condition of the tire model 1, the load condition, the camber angle, the friction coefficient between the tire model 1 and the road surface model, and the like are set. Furthermore, as the boundary conditions, an angular velocity corresponding to the traveling speed, a translational speed, a lateral force, and the like are set.

  In internal pressure addition of the tire model 1, for example, the tire model 1 after being filled with the internal pressure is calculated based on the internal pressure condition. As for the internal pressure, for example, in the standard system including the standard on which the tire is based, it is desirable that the air pressure defined by each standard be set.

  In the contact between the tire model 1 and the road surface model, for example, the deformation of the tire model 1 after internal pressure filling is calculated based on the load condition, the camber angle, the friction coefficient, and the like. Thus, the tire model 1 that is in contact with the road surface model is calculated.

  Next, a calculation step S3 is performed on the simulation method. In the calculation step S3, for example, the computer runs the tire model 1 on the road surface model previously determined in step S2, and calculates the wear performance of the tread portion. As shown in FIG. 2, it is desirable that the wear performance when rolling the tire model 1 in a predetermined tire rotational direction R is calculated for each node P (j) of each element F (i).

  For example, wear energy E is used as the wear performance of the present embodiment. The wear energy E is the product of the acting shear force and the amount of slip for each element F (i) of the rolling tread portion 2 until the element F (i) is separated from the ground surface model. Is a physical quantity obtained by calculating in unit time steps and summing them. In this embodiment, the shear force in the tire circumferential direction and the tire axial direction received during contact with the ground and the slip in the acting direction of each shear force at every unit time for all the node points P (j) appearing on the tread surface of the tread portion 2 The quantity is calculated. The wear energy E of the present embodiment is obtained as the sum of the products of the respective shear forces in the tire circumferential direction and the tire axial direction and the respective slip amounts.

  As the wear performance, a unit time wear amount D calculated based on the wear energy E and the material wear performance of the tread portion 2 may be further used. The unit time wear amount D of the present embodiment is calculated as the product of the wear energy E during contact and the wear coefficient K of the material of the tread portion 2 at all the nodes P (j) appearing on the tread surface in the tread portion 2 Ru.

  As shown in FIG. 1, the simulation method next performs a correction step S4. In the correction step S4, for example, the computer corrects the tread portion of the tire model 1 to a worn state based on the wear performance. In the correction step S4 of the present embodiment, for example, the coordinate value of each node P (j) is corrected based on the unit time wear amount D of each node P (j) of the tread portion 2 shown in FIG.

  Next, in the simulation method, an end determination step S5 is performed. In the end determination step S5, the computer determines whether to repeatedly execute the calculation step S3 and the correction step S4 or to end the calculation step S3 and the correction step S4 based on the wear performance of the tread portion 2. .

  In the end determination step S5 of the present embodiment, for example, at least two nodes P (j) among the nodes P (j) of the tread portion 2 shown in FIG. 2 are set as evaluation points V (j). . In the end determination step S5, the end is determined based on the wear performance of the at least two evaluation points V (j). The evaluation point V (j) may be set to any point between the nodes P (j).

  FIG. 3 is a partially enlarged view of the tire model 1 of FIG. A block 3 adjacent to the tire equator C is illustrated in FIG. As shown in FIG. 3, to evaluate the partial wear of block 3, select any two evaluation points V (j) in block 3 and select the wear performance of the two evaluation points V (j). Preferably, the degree of approximation X is calculated. When the evaluation points V (j) are three or more, among the evaluation points V (j), the evaluation point V (j) having the lowest wear performance and the evaluation point V (j) having the highest wear performance Preferably, the degree of approximation X with j) is calculated.

  The end determination step S5 of FIG. 1 is, for example, based on the predetermined threshold value T, when it is determined that the degree of approximation X of the wear performance of the two evaluation points V (j) shown in FIG. , Calculation step S3 and correction step S4 are repeatedly executed. When it is determined that the degree of approximation X is high, the calculation step S3 and the correction step S4 are ended. The threshold value T is desirably set in the initial setting of step S2 shown in FIG.

  The degree of approximation X is represented, for example, by the difference between the wear performance of the two evaluation points V (j) shown in FIG. 3 or the ratio of the wear performance of the two evaluation points V (j).

  When the degree of approximation X is represented by the difference in wear performance between the two evaluation points V (j), a low degree of approximation X means, for example, that the absolute value of the difference in wear performance is larger than the threshold T. Means Moreover, that the degree of approximation X is high means that the absolute value of the difference in wear performance is equal to or less than the threshold value T.

  When the degree of approximation X is represented by the ratio of the wear performance of the two evaluation points V (j), the degree of approximation X is, for example, a positive value of 1 or less obtained by dividing the smaller wear performance by the larger wear performance. Is represented by In this case, the low degree of approximation X means that the ratio of wear performance is smaller than the threshold value T. Further, that the degree of approximation X is high means that the ratio of wear performance is equal to or more than the threshold value T.

  FIG. 4 is a cross-sectional view at the end of the simulation of the line AA of the block 3 of FIG. 3 when the present embodiment is executed according to the processing procedure shown in FIG. In FIG. 4, a cross-sectional view of the initial stage of the simulation is shown by an imaginary line. As shown in FIG. 3 and FIG. 4, in the present embodiment, H / T uneven wear, which is uneven wear in the tire circumferential direction of the block 3, is evaluated.

  The evaluation point V (j) of the present embodiment is a first evaluation point V (1) defined in advance in the first arrival side area in the tire rotation direction R of the block 3 and the second arrival side area in the tire rotation direction R of the block 3 And a second evaluation point V (2) defined in advance. Therefore, in the present embodiment, the termination determination of the simulation method is performed based on the wear performance of the first evaluation point V (1) and the wear performance of the second evaluation point V (2).

  In FIG. 4, at the end of the simulation, the total wear amount W2 at the second evaluation point V (2) in the rear attachment side area is larger than the total wear amount W1 at the first evaluation point V (1) in the front arrival side area. The example which H / T uneven wear generate | occur | produces is shown. In the present embodiment, since the timing of the end of the calculation is determined in the end determination step S5 of FIG. 1, the uneven wear state as shown in FIG. 4 can be evaluated accurately and quickly.

  5 is a cross-sectional view at the end of the simulation of line B-B of block 3 of FIG. 3 when another embodiment is performed in accordance with the processing procedure shown in FIG. In FIG. 5, a cross-sectional view of the initial stage of simulation is shown by an imaginary line. As shown in FIGS. 3 and 5, in this embodiment, Sh / Cr uneven wear, which is uneven wear in the tire axial direction of the block 3, is evaluated.

  The block 3 of this embodiment includes an inner region in the tire axial direction near the tire equator C and an outer region in the tire axial direction far from the tire equator C. The evaluation points V (j) of this embodiment are a third evaluation point V (3) defined in advance in the inner area of the block 3 and a fourth evaluation point V (4) defined in advance in the outer area of the block 3. And contains. Therefore, in this embodiment, the termination determination of the simulation method is performed based on the wear performance of the third evaluation point V (3) and the wear performance of the fourth evaluation point V (4).

  FIG. 5 shows that at the end of the simulation, the total wear amount W4 of the fourth evaluation point V (4) in the outer region is larger than the total wear amount W3 of the third evaluation point V (3) in the inner region. An example in which uneven wear occurs is shown. Also in this embodiment, since the timing of the end of the calculation is determined in the end determination step S5 of FIG. 1, the uneven wear state as shown in FIG. 5 can be accurately and quickly evaluated.

  In still another embodiment, as shown in FIG. 3, wear performance may be calculated for all the nodes P (j) appearing on the tread surface of the block 3. In this case, the evaluation point V (j) is the evaluation point V (j) having the lowest wear performance in the block 3, for example, the fifth evaluation point V (5) and the highest wear performance in the block 3. And an evaluation point V (j) having, for example, a sixth evaluation point V (6). Therefore, in this embodiment, the termination determination of the simulation method is performed based on the wear performance of the fifth evaluation point V (5) and the wear performance of the sixth evaluation point V (6).

  In this embodiment, the maximum partial wear can be evaluated based on the maximum wear performance and the minimum wear performance of the block 3. Such an evaluation is effective when it is not possible to predict what kind of uneven wear will occur.

  As mentioned above, although the especially preferable embodiment of this invention was explained in full detail, this invention can be deform | transformed into a various aspect, and can be implemented, without being limited to embodiment shown.

  As an example, the H / T uneven wear was evaluated for the blocks of the tread portion of the tire model according to the processing procedure shown in FIG. As a comparative example, the H / T uneven wear of the example was evaluated by the conventional method in which the number of repetitions of the calculation process and the correction process is predetermined. Comparative Example 1 in which the number of repetitions was set to 5 and Comparative Example 2 in which the number of repetitions was set to 10 were calculated.

The common specifications of the example and the comparative example are as follows.
Tire size: 215 / 55R17
Rim: 17 x 7 J
Internal pressure: 230 kPa
Load: 3.51 kN
Camber angle: 1.7 °

  In the embodiment, the absolute value | E1-E2 | of the difference between the wear energy E1 of the first evaluation point V (1) and the wear energy E2 of the second evaluation point V (2) is a predetermined threshold value T1. The simulation was ended when it became below. The threshold value T1 is 30 J / m 2. As schematically illustrated in FIG. 4, in the embodiment, the total wear amount W1 of the first evaluation point V (1) of the first arrival side area is the total of the second evaluation point V (2) of the rear arrival side area. The H / T uneven wear with a larger wear amount W2 was confirmed.

  FIG. 6 is a cross-sectional view schematically showing the cross section of the block at the end of the simulation according to Comparative Example 1. As shown in FIG. 6, also in Comparative Example 1, the total wear amount at the second evaluation point V (2) in the rear attachment side area than the total wear amount W1 at the first evaluation point V (1) in the front arrival side area. The larger H / T uneven wear was confirmed for W2.

  FIG. 7 is a cross-sectional view schematically showing the cross section of the block at the end of the simulation according to Comparative Example 2. As shown in FIG. 7, also in Comparative Example 2, the total wear amount at the second evaluation point V (2) in the rear attachment side area than the total wear amount W1 at the first evaluation point V (1) in the front arrival side area. The larger H / T uneven wear was confirmed for W2.

  Step amount (W2-W1) which is a difference between the total wear amount W1 of the first evaluation point V (1) and the total wear amount W2 of the second evaluation point V (2) for the example and the comparative examples 1 and 2 And the calculation times are shown in Table 1. The calculation time is indexed with Comparative Example 2 being 100. The smaller the number, the shorter the calculation time.

  The step amount (W2-W1) of the comparative example 1 is about 20% smaller than the step amount (W2-W1) of the example, and it is understood that the tendency of uneven wear is underestimated in the comparative example 1. The In addition, the step amount (W2-W1) of the comparative example 2 and the step amount (W2-W1) of the embodiment are substantially equal, and the accuracy of evaluating the tendency of uneven wear of the comparative example 2 and the embodiment is equivalent. there were. That is, it was confirmed that in the example, uneven wear can be evaluated accurately and quickly as compared with each comparative example.

1 tire model 2 tread portion 3 block S3 calculation step S4 correction step S5 end determination step

Claims (8)

A tire simulation method for evaluating the wear performance of a tire using a computer,
Inputting a tire model including a tread portion into the computer;
A calculation step of causing the tire model to run on a predetermined road surface model and calculating the wear performance of the tread portion;
A correcting step of correcting the tread portion of the tire model to a worn state based on the wear performance by the computer;
The computer determines whether to repeat the calculation process and the correction process or to end the calculation process and the correction process based on the wear performance of at least two evaluation points of the tread portion A method of simulating a tire comprising the steps of: determining. The end determination step calculates an approximation of the wear performance of the two evaluation points, and when it is determined that the approximation is low based on a predetermined threshold value, the calculation and the correction are performed. As well as
The tire simulation method according to claim 1, wherein the calculation step and the correction step are ended when it is determined that the degree of approximation is high.   The tire simulation method according to claim 2, wherein the degree of approximation is represented by a difference in wear performance of the two evaluation points or a ratio of wear performance of the two evaluation points. The tread portion includes at least one block,
The evaluation points include a first evaluation point defined in advance in the first arrival side area in the tire rotation direction of the block and a second evaluation point defined in advance in the second arrival side area of the block in the tire rotation direction The simulation method of the tire in any one of claim | item 1 thru | or 3. The tread portion includes at least one block,
The block includes an inner region in the tire axial direction and an outer region in the tire axial direction,
The evaluation point according to any one of claims 1 to 3, wherein the evaluation point includes a third evaluation point defined in advance in the inner area of the block and a fourth evaluation point defined in advance in the outer area of the block. Tire simulation method. The tread portion includes at least one block,
The said evaluation point is described in any one of claims 1 to 3 including a fifth evaluation point having the lowest wear performance among the blocks and a sixth evaluation point having the highest wear performance among the blocks. Tire simulation method.   The tire simulation method according to any one of claims 1 to 6, wherein wear energy is used for the wear performance of each of the evaluation points.   The tire simulation method according to any one of claims 1 to 6, wherein as the wear performance of each evaluation point, a unit time wear amount calculated based on wear energy and material wear performance of the tread portion is used.

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