JP6400459B2 - Tire rim assembly state analysis apparatus, method and program thereof - Google Patents

Description

  The present invention relates to an analysis apparatus, a method, and a program for analyzing a tire rim assembly state.

  A method of simulating tire characteristics by numerical calculation using a computer is known. In such a simulation method, the tire to be evaluated is approximated by a tire model (for example, a tire finite element model divided into a finite number of elements) modeled with elements that can be handled by a numerical analysis method. Physical properties such as density and elastic modulus are given to the tire, boundary conditions such as internal pressure and load are given to the tire model, and the deformation state of each element is calculated to simulate the deformation and motion state of the tire.

  When such a simulation is performed, it is necessary to acquire a tire model in a state assembled to a rim of a wheel, and various methods have been proposed. For example, in Patent Document 1, initial conditions for contact analysis between a tire model and a rim model are set so that the tire model contacts only the bead toe with the rim model and the bead toe contacts the rim model with a minute overlap of a predetermined value or less. Thus, it is disclosed that the tire bead portion is appropriately brought into contact with the rim to obtain a tire cross-sectional shape in a use state.

  In Patent Document 2, when a tire model and a rim model are fitted, the rim model is arranged at an initial position on the inner side in the tire radial direction and on the outer side in the tire axial direction with respect to the normal position, and then the rim model is moved inward in the tire axial direction. After the tire model is brought into contact with the rim model, the rim model is moved outward in the tire radial direction so as to be fitted to the tire model.

  In order to accurately evaluate the tire performance during rolling or non-rolling of the tire, such as the tire bead removal performance, it is required to accurately reproduce the assembled state of the tire and the rim. At that time, the rim of the wheel is generally provided with a convex part called a hump to prevent bead disengagement. No method has been proposed to reproduce the assembled state of.

  Although it is conceivable to use the methods of Patent Documents 1 and 2 to reproduce the assembled state of the humped rim, for example, as in Patent Document 1, the rim model is displaced in the tire axial direction inner side and the tire radial direction outer side during contact analysis. In the method, since it is humped, it may be difficult to obtain a stable solution. On the other hand, in the method of Patent Document 2, when the humped rim model is moved inward in the tire axial direction, the bead toe 102 of the tire model 100 is moved outward in the tire axial direction of the hump 112 of the rim model 110 as shown in FIG. Then, as shown in FIG. 12B, the rim model 110 is moved outward in the tire radial direction. Therefore, the actual phenomenon that the bead toe gets over the hump from the inside of the hump and is attached to the outside is not reproduced, that is, the proper fitting state is not reproduced, and there is a problem that an accurate calculation result cannot be obtained. .

  Patent Document 3 discloses that the tire model is fitted using a humped rim model, but the fitting process is analyzed using a three-dimensional tire model and a rim model. There is a problem that the analysis time becomes long or the analysis becomes unstable, and a method for reproducing the assembly state in the two-dimensional analysis is required.

JP 2014-111141 A JP 2013-237319 A JP 2006-306372 A

  In view of the above, an object of the present invention is to provide a tire rim assembly state analysis apparatus, method, and program that can reproduce the assembly state of a tire and a humped rim by two-dimensional analysis.

  A tire rim assembly state analysis apparatus according to the present invention is an analysis apparatus that analyzes a state in which a tire is assembled to a rim by simulation; a tire model setting unit that sets a tire model that reproduces a tire cross-sectional shape; A first rim model setting unit for setting a humpless rim model in which a hump is not provided, and a second rim model for reproducing the cross-sectional shape of the hump; A rim model setting unit; a first rim model disposition unit configured to dispose the humpless rim model at an initial position in which a rim flange surface of the humpless rim model is spaced apart from the bead side surface of the tire model in the tire axial direction; Initial position of the model outside the tire axis with respect to the normal position A second rim model placement unit arranged at a position; a first contact for performing deformation calculation of the tire model while displacing the humpless rim model from an initial position to a normal position by contact analysis between the tire model and the humpless rim model. A second contact analysis for performing deformation calculation of the tire model while displacing the hump model from an initial position to a normal position by contact analysis of the tire model fitted to the humpless rim model and the hump model; And a part.

  According to the present invention, in a two-dimensional analysis, a humped rim is modeled by dividing it into a humpless rim model and a hump model, and each can be separately displaced and fitted to obtain a stable solution. It is possible to reproduce an appropriate assembly state.

The block diagram of the analyzer concerning one embodiment. The flowchart of the analyzer which concerns on one Embodiment. Tire model illustration. (A) is a figure of a rim model without a hump, (b) is a figure of a hump model, (c) is a figure of a rim model with a hump. The figure which shows the initial position of a tire model and a rim model. The principal part enlarged view of FIG. The figure of the tire model and rim model after a 1st contact analysis. The principal part enlarged view of FIG. The figure of the tire model and rim model after a 2nd contact analysis. The figure which shows the assembly | attachment state of the tire model after a regular internal pressure load, and a rim model. The figure of the tire model in a rim assembly state. The figure which shows the assembly | attachment state of the tire model which concerns on a comparative example, and a rim model with a hump.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A rim assembly state analysis apparatus 10 according to an embodiment is an analysis apparatus that analyzes a state in which a tire is assembled to a rim by simulation, and as illustrated in FIG. 1, an input unit 12, a tire model setting unit 14, and a rim model setting unit. 16, a contact analysis model creation unit 24, a first contact analysis unit 32, a second contact analysis unit 34, a normal internal pressure load unit 36, a rim model replacement unit 38, a friction coefficient changing unit 40, and an output unit 42. The rim model setting unit 16 includes a first rim model setting unit 18, a second rim model setting unit 20, and a third rim model setting unit 22, and the contact analysis model creating unit 24 includes a first rim model placement unit 26, a second rim model setting unit 26, and a second rim model setting unit 26. A rim model placement unit 28 and an analysis condition setting unit 30 are included.

  The analysis device 10 can be realized by using, for example, a general-purpose computer having a mouse and a keyboard (including a processor (CPU), a memory such as a ROM and a RAM, and a storage device such as an HDD) as basic hardware. Is possible. That is, the input unit 12, the tire model setting unit 14, the rim model setting unit 16 (specifically, the first rim model setting unit 18, the second rim model setting unit 20, and the third rim model setting unit 22), the contact analysis model creating unit 24. (Specifically, the first rim model placement unit 26, the second rim model placement unit 28, and the analysis condition setting unit 30), the first contact analysis unit 32, the second contact analysis unit 34, the normal internal pressure load unit 36, and the rim model replacement unit 38, the friction coefficient changing unit 40, and the output unit 42 can be realized by causing a processor mounted on the computer to execute a program. At this time, the analysis device 10 may be realized by installing the above program in a computer in advance, or may be stored in a storage medium such as a CD-ROM or distributed through the network. This program may be realized by appropriately installing it on a computer.

  Hereinafter, the configuration and functions of the above-described units will be described in order.

[1] Input unit 12
The input unit 12 acquires data on the pneumatic tire and rim to be analyzed. The tire data includes various data (tire design information) about the tire, including the tire cross-sectional shape. Specifically, the dimensions of the tire, such as the outer shape and internal structure, and the tire are configured. The shape, arrangement, material property value, etc. of each tire member such as tread rubber, sidewall rubber, belt, carcass ply, bead core, and chacher are input.

  The data on the rim includes a rim parameter value necessary for reproducing a cross-sectional shape of a portion in contact with the tire, a rim to be analyzed, a rim diameter, and the like. In the present embodiment, data on a rim with a hump in which a hump that is a convex portion for preventing detachment from the rim is provided on the rim sheet surface that is in contact with the bottom surface of the bead.

  Input of data regarding these tires and rims may be performed using a keyboard, or may be performed via a recording medium such as a CD-ROM, a network, or the like.

[2] Tire model setting unit 14
The tire model setting unit 14 sets a two-dimensional tire model that reproduces the tire cross-sectional shape (the meridian cross-sectional shape) based on the information about the tire cross-sectional shape input by the input unit 12. In this example, as shown in FIG. 3, a tire model T1 that is a finite element model in which the tire cross-sectional shape is divided into finite elements is created. A method for creating the tire model T1 is not particularly limited, and a known method can be adopted. Note that a two-dimensional tire model created in advance may be acquired by the input unit 12 and set as a tire model to be analyzed (this also applies to a rim model described later).

  In FIG. 3, the bead portion T10 of the tire model T1 is shown in an enlarged manner, the reference symbol T11 indicates a bead core, and the reference symbol T12 indicates a bead toe. Reference numeral T13 indicates a bead bottom surface that is an inner surface in the tire radial direction of the bead portion T10, and reference numeral T14 indicates a bead side surface that extends to the heel side of the bead bottom surface T13 and extends outward in the tire radial direction. Since the two-dimensional model is used, the bead bottom surface T13 and the bead side surface T14 are both represented by lines.

  In the present specification, the tire axial direction J is a direction parallel to the tire rotation axis, and the tire radial direction K is a direction perpendicular to the tire rotation axis.

[3] Rim model setting unit 16
The rim model setting unit 16 sets a rim model that reproduces the cross-sectional shape of the portion of the rim that contacts the tire. The rim model setting unit 16 includes a first rim model setting unit 18, a second rim model setting unit 20, and a third rim model setting unit 22. Have. In this embodiment, an analytical rigid body that is not divided into finite elements is used as the rim model. However, a finite element model that is divided into finite elements may be used. In this case, the rim model may be modeled as a deformed body or a rigid body. You may model it.

[4] First rim model setting unit 18
The first rim model setting unit 18 is a rim model that reproduces the cross-sectional shape (outline of the cross-sectional shape) of the portion of the rim that contacts the tire based on the information related to the rim cross-sectional shape input by the input unit 12. Set a humpless rim model that is not provided. FIG. 4 (a) shows an example thereof. The humpless rim model R1 includes a rim seat surface R4 that abuts the bead bottom surface T13, a rim seat surface R4 that extends to the outer side in the tire radial direction Ko, and a bead side surface T14. It includes a rim flange surface R5 that abuts. Since it is a two-dimensional model, both the rim seat surface R4 and the rim flange surface R5 are represented by lines.

  The rim seat surface R4 is configured by a straight line that is inclined so as to be positioned on the inner side Ki in the tire radial direction as the inner side Ji in the tire axial direction, and no hump is provided. That is, the humpless rim model R1 has a shape in which the hump R6 is omitted from the rim model R3 with hump shown in FIG. Although FIG. 4 shows the humpless rim model R1 on one side in the tire axial direction J, a similar humpless rim model is also created on the other side (this also applies to a hump model R2 and a rim model R3 with hump described later). .

[5] Second rim model setting unit 20
The second rim model setting unit 20 sets a hump model that reproduces the cross-sectional shape of the hump based on the information about the rim cross-sectional shape input by the input unit 12. FIG. 4 (b) shows an example thereof, and the hump model R2 is constituted by the outline of only the hump portion provided on the rim seat surface of the rim with the hump, and the hump shown in FIG. 4 (c). It has a shape overlapping the hump R6 of the attached rim model R3.

[6] Third rim model setting unit 22
The third rim model setting unit 22 sets a rim model with a hump that reproduces a cross-sectional shape of a portion of the rim with a hump that comes into contact with the tire based on information about the rim cross-sectional shape input by the input unit 12. FIG. 4C shows an example thereof. The humped rim model R3 includes a rim seat surface R4, a rim flange surface R5, and a hump R6 provided on the rim seat surface R4. The hump R6 is a convex portion protruding in a curved surface shape from the rim seat surface R4, and as shown in FIG. 11, is provided at a position where the bead toe T12 is applied to the slope of the outer side in the tire axial direction Jo.

[7] Contact analysis model creation unit 24
The contact analysis model creation unit 24 creates a contact analysis model by combining the tire model T1 and the rim models R1 and R2, and sets conditions in the contact analysis. The first rim model placement unit 26 and the second rim model placement unit 28 and an analysis condition setting unit 30.

[8] First rim model placement unit 26
The first rim model placement unit 26 places the humpless rim model R1 at a predetermined initial position with respect to the tire model T1. That is, the positional relationship between the tire model T1 and the humpless rim model R1 is set so that the initial position in the contact analysis is set. As shown in FIG. 5, the rim flange surface R5 of the humpless rim model R1 is a tire model. The humpless rim model R1 is disposed at an initial position that is spaced apart from the bead side surface T14 of the tire T1 in the tire axial direction outer side Jo.

  At this time, in the present embodiment, as shown in an enlarged view in FIG. 6, the rim model R1 without hump is moved to the normal position of the rim (the rim standard) so that the tire model T1 contacts the rim model R1 without hump only with the bead toe T12. (Position corresponding to the value) is arranged at an initial position shifted in the tire radial direction K and the tire axial direction J. The bead toe T12 is in contact with the humpless rim model R1 at the rim seat surface R4.

  In FIG. 6, the humped rim model R3 is shown at the normal position, and the position of the rim model R3 is the normal position. The humpless rim model R1 is disposed at an initial position located on the outer side in the tire axial direction Jo with respect to the normal position, and more specifically, disposed at an initial position located on the inner side Ki in the tire radial direction and on the outer side in the tire axial direction Jo. The However, depending on the bead width and the rim shape in the tire design, for example, the bead width and the rim shape may be arranged at an initial position located at the outer side in the tire radial direction Ko and the outer side in the tire axial direction Jo with respect to the normal position.

  By arranging in this way, the displacement in the tire radial direction K can be reduced when the humpless rim model R1 is displaced during the contact analysis. That is, when displacing toward the tire axis direction inner side Ji, the rim model R1 without hump and the tire model T1 can be fitted while reducing the angle formed with the tire axis direction J. The fitting can be reproduced.

[9] Second rim model placement unit 28
The second rim model placement unit 28 is for placing the hump model R2 at a predetermined initial position with respect to the tire model T1, and as shown in FIG. It is arranged at the initial position located at Jo.

  At this time, in this embodiment, the apex R2a of the hump model R2 exceeds the rim seat surface R4 of the humpless rim model R1 at the tire axially inner side Ji from the bead core center T11a of the tire model T1 fitted to the humpless rim model R1. The hump model R2 is disposed at an initial position shifted from the normal position to the outer side in the tire axial direction Jo and to the inner side in the tire radial direction so as to start to come into contact with the model T1. That is, as shown in FIG. 8, when the tire axial direction position of the bead core center T11a in a state where the tire model T1 is fitted to the humpless rim model R1 is J1, the hump model R2 that is displaced toward the normal position at the time of contact analysis. The hump model R2 is arranged so that the apex R2a of the tire extends beyond the rim seat surface R4 at the position in the tire axial direction inner side Ji from the axial position J1 to the outer side in the tire radial direction Ko. In this way, by setting the hump model R2 to an initial position that passes through the inner inner diameter side (lower left in FIG. 8) of the bead core T11, reproduction of the movement of the vicinity of the bead toe T12 from the inner side of the hump toward the outer side is reproduced. It is possible to get over the hump from an appropriate direction. In particular, since the bead core T11 has high rigidity, if the hump model R2 is displaced toward the inner side Ji in the tire axial direction so as to pass through the entire bead bottom surface T13, the calculation may not easily converge during the contact analysis. By passing the inner diameter side as described above, it is possible to reproduce the hump overcoming from an appropriate direction while suppressing the influence of the rigid bead core T11.

  An example for arranging in this way will be described. In the tire model T1 before assembling the rim shown in FIG. 3, the bead core T11 in the tire axial direction J from the tire axial inner end (in this example, the axial inner end at the tire radial outer end) T11b to the bead side surface T14. The distance L is obtained. In the rim model R3 with a hump at the normal position, as shown in FIG. 6, the distance L is taken from the straight portion R5a of the rim flange surface R5 with which the bead side surface T14 contacts to the inner side Ji in the tire axial direction, and the rim seat surface R4 A point A corresponding to the axial position is taken. The distance (j, k) of each component in the tire axial direction J and the radial direction K from the vertex R6a of the hump R6 at the regular position to the point A is obtained. The hump model R2 is arranged so that the vertex R2a is located at a position (nj, nk) obtained by multiplying the distance (j, k) by n from the vertex R6a (where n is a real number greater than 1). That is, the hump model R2 is arranged such that the vertex R2a is positioned on the extended line of the straight line drawn from the vertex R6a of the hump R6 at the regular position to the point A.

[10] Analysis condition setting unit 30
The analysis condition setting unit 30 sets conditions necessary for contact analysis between the tire model T1, the humpless rim model R1, and the hump model R2. As the contact analysis conditions, rim models R1 and R2 that are analytical rigid bodies are defined as wall surfaces (contact surfaces) that restrain deformation of the bead portion T10 of the tire model T1. Further, a boundary condition is set for the tire model T1 so that the tire model T1 does not bite into the contact surfaces of the rim models R1 and R2. Also, the difference from the initial position to the normal position of the rim model R1 with hump and the difference from the initial position to the normal position of the hump model R2 are respectively defined as forced displacement values, and the forced displacement value is stepped from 0% to 100%. The number of calculation steps to be changed is set individually.

  Further, a friction coefficient between the tire model T1 and the rim models R1 and R2 is set. As the friction coefficient, the friction coefficient after assembling the rim (the friction coefficient used in the actual tire performance analysis; hereinafter referred to as the actual analysis friction coefficient) is μ = 0.6 to 1.2 as an example, At the time of contact analysis, it is preferable to set a value lower than the actual analysis friction coefficient, for example, within a range of μ = 0 to actual analysis friction coefficient ÷ 2, taking into account that wax is applied between the two.

  In addition, conditions such as the magnitude of the internal pressure applied to the tire model T1, the timing of loading, and the manner of loading are set during contact analysis. As the internal pressure, for example, a minute internal pressure may be applied to the tire model T1 in advance to displace the rim models R1 and R2, or the internal pressure may be gradually applied while the rim models R1 and R2 are displaced. The internal pressure may be applied after the displacement, and then the hump model R2 may be displaced. Preferably, an internal pressure is gradually applied while displacing the humpless rim model R1, and then the hump model R2 is set to be displaced while the internal pressure remains constant. This setting stabilizes the analysis. The internal pressure applied during the contact analysis is preferably an internal pressure lower than the normal internal pressure, and is preferably 80% or less of the normal internal pressure, more preferably 100 kPa or more and 80% or less of the normal internal pressure.

  Here, the normal internal pressure is an internal pressure corresponding to the use of the tire loaded on the tire model when the tire performance is simulated after the rim is assembled according to the present embodiment. For example, “maximum air pressure” in the JATMA standard, “TIRE in the TRA standard” “Maximum value” described in “LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” or “INFLATION PRESSURE” in the ETRTO standard.

[11] First contact analysis unit 32
The first contact analysis unit 32 performs 2D contact analysis between the tire model T1 and the humpless rim model R1. The first contact analysis unit 32 performs the tire model while linearly displacing the humpless rim model R1 from the initial position to the normal position by the contact analysis between the tire model T1 and the humpless rim model R1 under the contact analysis conditions. The deformation calculation of T1 is performed.

  Specifically, the forced displacement value, which is the difference between the initial position and the normal position, is divided by the number of calculation steps, and the humpless rim model R1 is moved from the initial position shown in FIG. The deformation calculation of the tire model T1 is performed while displacing in a stepwise manner. Accordingly, as shown in FIGS. 7 and 8, the tire model T1 is fitted to the humpless rim model R1. The deformation calculation itself of the tire model T1 in such a contact analysis can be performed using commercially available FEM analysis software such as “ABAQUS” manufactured by Dassault Systèmes, and “MARC” manufactured by MSC Software Co., Ltd. It is also possible to create and execute a unique program using a general-purpose programming language (Fortran, etc.).

  In this example, the direction of forced displacement is the tire radial direction outer side Ko and the tire axial direction inner side Ji, but since this direction is determined by the relationship between the initial position and the normal position, for example, the tire radial direction inner side Ki and You may force-displace to tire axial direction inner side Ji. In the preferred embodiment, as described above, the first contact analysis unit 32 loads the tire model T1 with an internal pressure lower than the normal internal pressure and performs deformation calculation of the tire model T1.

[12] Second contact analysis unit 34
The second contact analysis unit 34 performs 2D contact analysis between the tire model T1 fitted to the humpless rim model R1 and the hump model R2. In other words, the second contact analysis unit 34 linearly displaces the hump model R2 from the initial position to the normal position by the contact analysis between the tire model T1 and the hump model R2 under the contact analysis conditions. The deformation calculation of T1 is performed.

  Specifically, the forced displacement value, which is the difference between the initial position and the normal position, is divided by the number of calculation steps, and the hump model R2 is determined from the initial position shown in FIGS. The deformation calculation of the tire model T1 is performed in the same manner as the first contact analysis unit 32 while being displaced stepwise toward the outside position toward the outer side Ko. As a result, as shown in FIG. 9, the tire model T1 is fitted to the humpless rim model R1 and the hump model R2. In the preferred embodiment, as described above, the second contact analysis unit 34 does not change the internal pressure while the tire model T1 is loaded with an internal pressure lower than the normal internal pressure loaded by the first contact analysis unit 32. Then, deformation calculation of the tire model T1 is performed.

[13] Regular internal pressure load section 36
The normal internal pressure load unit 36 loads the normal internal pressure to the tire model T1 after the tire model T1 and the hump model R2 are fitted. That is, as shown in FIG. 9, after the humpless model R1 and the hump model R2 are moved to the normal positions, the tire model T1 is fitted into the tire model T1, and the tire model T1 is subjected to deformation calculation while performing internal pressure filling. As shown in FIG. 10, the tire model T1 at the stage where the internal pressure during use is filled is obtained.

[14] Rim model replacement unit 38
The rim model replacement unit 38 replaces the humpless rim model R1 and the hump model R2 at the normal positions with the humped rim model R3 after fitting the tire model T1 and the hump model R2. That is, after removing the humpless rim model R1 and the hump model R2, the humped rim model R3 is placed at the normal position. As a result, as shown in FIG. 11, a tire model T1 having a cross-sectional shape in a use state in which a normal internal pressure is loaded and assembled to the humped rim model R3 is obtained.

[15] Friction coefficient changing unit 40
The friction coefficient changing unit 40 changes the friction coefficient between the tire model T1 and the humped rim model R3 from the low value set above to the actual analysis friction coefficient.

[16] Output unit 42
The output unit 42 outputs the two-dimensional tire model T1 in the use state shown in FIG. 11 obtained as described above. The tire model can be output by being displayed on a display or printed by a printer. It can also be stored in a storage device such as a hard disk and used to generate a three-dimensional model for various tire behavior simulations.

  Next, the operation state of the analysis apparatus 10 according to the present embodiment will be described based on the flowchart of FIG.

  In step S1, the input unit 12 acquires data on the pneumatic tire and rim to be analyzed. Next, in step S2, the tire model setting unit 14 sets a two-dimensional tire model T1 as shown in FIG. 3 based on the acquired information about the tire cross-sectional shape. In step S3, the first rim model setting unit 18, the second rim model setting unit 20, and the third rim model setting unit 22 are respectively configured to have a humpless rim model R1 as shown in FIG. The hump model R2 and the humped rim model R3 are set as a pair on the left and right. The order of steps S2 and S3 may be reversed or may be performed simultaneously.

  Next, in step S4, the first rim model placement unit 26 places the humpless rim model R1 at the predetermined initial position with respect to the tire model T1, and the second rim model placement unit 28 sets the hump model R2 to the predetermined model. It arrange | positions to an initial position (refer FIG.5 and FIG.6). Then, the process proceeds to step S5.

  In step S5, the analysis condition setting unit 30 sets conditions necessary for contact analysis between the tire model T1 and the rim models R1, R2, such as a friction coefficient between the tire model T1 and the rim models R1, R2. Then, the process proceeds to step S6.

  In step S6, the first contact analysis unit 32 linearly displaces the humpless rim model R1 from the initial position to the normal position by the contact analysis between the tire model T1 and the humpless rim model R1 under the contact analysis conditions. However, deformation calculation of the tire model T1 is performed. At this time, it is preferable that the internal pressure is gradually applied until a predetermined internal pressure lower than the normal internal pressure is obtained while the rim model R1 without hump is displaced and moved. As a result, as shown in FIGS. 7 and 8, the tire model T1 is fitted to the humpless rim model R1.

  Next, in step S7, the second contact analysis unit 34 linearly displaces the hump model R2 from the initial position to the normal position by the contact analysis between the tire model T1 and the hump model R2 under the contact analysis conditions. However, deformation calculation of the tire model T1 is performed. At that time, preferably, the analysis is performed without changing the predetermined internal pressure lower than the normal internal pressure loaded in step S6. As a result, as shown in FIG. 9, the tire model T1 is fitted to the humpless rim model R1 and the hump model R2.

  Next, in step S8, the normal internal pressure loading unit 36 applies the normal internal pressure to the tire model T1, thereby obtaining the tire model T1 at a stage where the internal pressure during use is filled as shown in FIG. Then, the process proceeds to step S9.

  In step S9, the rim model replacement unit 38 replaces the humpless rim model R1 and the hump model R2 at the normal positions with the humped rim model R3 as shown in FIG. Then, the process proceeds to step S10.

  In step S10, the friction coefficient changing unit 40 changes the friction coefficient between the tire model T1 and the humped rim model R3 from the low value set in step S5 to the actual analysis friction coefficient. Then, the process proceeds to step S11.

  In step S11, the output unit 42 outputs the two-dimensional tire model T1 having the cross-sectional shape in the use state loaded with the normal internal pressure obtained as described above and assembled to the humped rim model R3. The two-dimensional tire model thus obtained can be used to create a three-dimensional model for simulating various behaviors of a pneumatic tire. That is, for example, a three-dimensional tire model can be created by developing a two-dimensional tire model in the tire circumferential direction and dividing the element at predetermined intervals in the circumferential direction.

  According to this embodiment as described above, the humped rim is modeled by dividing it into the humpless rim model R1 and the hump model R2, and after the humpless rim model R1 is displaced and fitted, the hump model R2 is displaced. By fitting the rim with a hump, the deformation calculation of the tire model at each calculation step is simplified and the calculation is more easily converged than when the humped rim is directly modeled and displaced. That is, when fitting the rim model R1 without a hump accompanied by a relatively large tire deformation, the rim seat surface R4 is calculated as a simple shape, and after fitting to the rim model R1 without a hump, only the hump is suppressed in a state where the large tire deformation is suppressed. When the deformation calculation is performed by displacing the model R2, the calculation is easily converged. Therefore, a solution can be obtained stably.

  Further, since the hump model R2 is fitted to the tire model T1 fitted to the non-hump rim model R1 by being displaced in the tire axial direction inner side Ji, the bead toe T12 gets over the hump from the inside of the hump and is attached to the outside. The phenomenon can be reproduced, and an appropriate fitting state can be reproduced.

  In this way, it is possible to reproduce the proper assembly state of the tire and the humped rim, and in subsequent simulations of various behaviors of pneumatic tires using a three-dimensional tire model, tire rolling such as bead disengagement performance etc. It becomes possible to evaluate the tire performance at the time or at the time of non-rolling with higher accuracy.

  In the above embodiment, the tire model T1 is created with the full width. However, for example, in the case of a symmetric tire, the rim assembly state may be analyzed using a tire model with a half cross section on one side of the tire equator line. In that case, the rim model need only be created on one side.

  Although one embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Rim assembly | attachment state analysis apparatus, 14 ... Tire model setting part, 18 ... 1st rim model setting part, 20 ... 2nd rim model setting part, 26 ... 1st rim model arrangement | positioning part, 28 ... 2nd rim model arrangement | positioning part, 32 ... 1st 1 contact analysis part 34 ... 2nd contact analysis part 36 ... regular internal pressure load part, T1 ... tire model, T10 ... bead part, T11a ... bead core center, T12 ... bead toe, T13 ... bead side surface, R1 ... rim model without hump, R2 ... Hump model, R3 ... Rim model with hump, R4 ... Rim seat surface, R5 ... Rim flange surface, J ... Tire axial direction, Jo ... Tire axial direction outer side, Ji ... Tire axial direction inner side, K ... Tire radial direction, Ko ... Tire radial outer side, Ki ... tire radial inner side

Claims (6)

An analysis device that analyzes a state where a tire is assembled to a rim by simulation,
A tire model setting unit for setting a tire model that reproduces the tire cross-sectional shape;
A first rim model setting unit for setting a rim model without a hump, which is a rim model that reproduces a cross-sectional shape of a portion of the rim that contacts a tire;
A second rim model setting unit for setting a hump model reproducing the cross-sectional shape of the hump;
A first rim model placement section for placing the humpless rim model at an initial position in which a rim flange surface of the humpless rim model is spaced apart from a bead side surface of the tire model in the tire axial direction;
A second rim model placement portion for placing the hump model at an initial position located on the outer side in the tire axial direction with respect to the normal position;
A first contact analysis unit that performs deformation calculation of the tire model while displacing the humpless rim model from an initial position to a normal position by contact analysis between the tire model and the humpless rim model;
A second contact analysis unit that performs deformation calculation of the tire model while displacing the hump model from an initial position to a normal position by contact analysis between the tire model fitted to the humpless rim model and the hump model;
A tire rim assembly state analyzing apparatus having:   The analysis apparatus according to claim 1, wherein the first rim model arrangement unit is arranged at an initial position where the tire model is in contact with the humpless rim model only with a bead toe.   The second rim model placement portion is in contact with the tire model across the rim seat surface of the non-hump rim model, with the apex of the hump model being in the tire axial direction inside the bead core center of the tire model fitted to the non-hump rim model. The analysis device according to claim 1 or 2, wherein the hump model is arranged at an initial position shifted from the normal position to the tire axial direction outer side and the tire radial direction inner side so as to start. After fitting the tire model and the hump model, the tire model has a normal internal pressure load portion that loads a normal internal pressure,
The first contact analysis unit and the second contact analysis unit include performing a deformation calculation of the tire model by applying an internal pressure lower than the normal internal pressure to the tire model. The analyzer according to item 1. An analysis method for analyzing a state where a tire is assembled to a rim by simulation,
A tire model setting step for setting a tire model that reproduces the tire cross-sectional shape;
A first rim model setting step for setting a rim model without a hump, which is a rim model that reproduces a cross-sectional shape of a portion of the rim that contacts the tire;
A second rim model setting step for setting a hump model reproducing the cross-sectional shape of the hump;
A first rim model arrangement step of arranging the humpless rim model at an initial position where a rim flange surface of the humpless rim model is spaced apart from a bead side surface of the tire model in the tire axial direction;
A second rim model arrangement step of arranging the hump model at an initial position located on the outer side in the tire axial direction with respect to the normal position;
A first contact analysis step of performing deformation calculation of the tire model while displacing the humpless rim model from an initial position to a normal position by contact analysis of the tire model and the humpless rim model;
A second contact analysis step of performing deformation calculation of the tire model while displacing the hump model from an initial position to a normal position by contact analysis of the tire model fitted to the humpless rim model and the hump model;
A tire rim assembly state analysis method. It is a program that analyzes the state of mounting the tire on the rim by simulation,
A tire model setting function for setting a tire model that reproduces the tire cross-sectional shape;
A first rim model setting function for setting a rim model without a hump, which is a rim model that reproduces a cross-sectional shape of a portion of the rim that contacts a tire;
A second rim model setting function for setting a hump model reproducing the cross-sectional shape of the hump;
A first rim model placement function for placing the humpless rim model at an initial position in which a rim flange surface of the humpless rim model is spaced apart from a bead side surface of the tire model in the tire axial direction;
A second rim model placement function for placing the hump model at an initial position located on the outer side in the tire axial direction with respect to the normal position;
A first contact analysis function for performing deformation calculation of the tire model while displacing the humpless rim model from an initial position to a normal position by contact analysis between the tire model and the humpless rim model;
A second contact analysis function for performing deformation calculation of the tire model while displacing the hump model from an initial position to a normal position by a contact analysis of the tire model fitted to the humpless rim model and the hump model;
Tire rim assembly state analysis program to achieve this.

Images