JP7137461B2 - SIMULATION APPARATUS, SIMULATION METHOD, AND PROGRAM - Google Patents

Description

The present invention relates to a simulation device, simulation method, and program.

Various simulations have been performed to accurately predict tire performance. In general, the outer surface shape of a tire model used in simulation is created from the inner surface shape of a mold. However, a tire that is actually manufactured has a shape different from the shape of the inner surface of the mold through a post-cure inflation (PCI) process that is performed after vulcanization. Therefore, it may not be possible to correctly evaluate tire performance with a tire model created based on the shape of the inner surface of the mold. On the other hand, a method has been proposed in which a tire model is created by performing an analysis that reproduces the PCI process (PCI analysis), and a tire shape that has undergone the PCI process is subjected to ground contact analysis (see, for example, Patent Document 1). ).

JP 2018-79789 A

By the way, since the PCI process is performed immediately after vulcanization molding, the temperature of the tire is high. On the other hand, when the ground contact test is performed, the temperature of the tire is normal temperature. Therefore, in order to perform a simulation that reproduces the PCI process and the grounding test with high accuracy, it is preferable to give physical property values that take this temperature change into consideration. In the method of Patent Literature 1, it is necessary to redefine various analysis conditions such as physical property values for PCI analysis and grounding analysis. However, since a tire is composed of many members, it takes time and effort to redefine various analysis conditions such as physical property values of all the members for each process. Therefore, the method of Patent Literature 1 has room for improvement from the viewpoint of facilitating the simulation.

An object of the present invention is to reproduce the outer surface shape of a tire after a PCI process with high accuracy and ease in a simulation apparatus, simulation method, and program to perform contact analysis.

A first aspect of the present invention includes an FEM modeling section that acquires a tire FEM model obtained by dividing a tire having an outer surface shape corresponding to an inner surface shape of a vulcanization mold into a plurality of elements, and immediately after vulcanization molding of the tire. and a contact analysis unit that performs contact analysis that reproduces the contact state of the tire after the PCI process, wherein the PCI analysis unit performs the PCI analysis. The analysis condition setting includes setting the elastic modulus of the belt member higher than the elastic modulus at room temperature by a predetermined value or more; and the PCI analysis condition setting unit. and a PCI analysis calculation unit that calculates the shape of the tire FEM model after the PCI process based on the analysis conditions set in , and the contact analysis unit is a part that sets the analysis conditions for the contact analysis. In setting the analysis conditions, the same physical property values as the physical property values set in the PCI analysis condition setting unit are set for each member of the tire FEM model except the belt member, and the elastic modulus of the belt member is set. a ground contact analysis condition setting unit including setting the modulus of elasticity at room temperature; and the tire ground contact performance based on the analysis conditions set by the ground contact analysis condition setting unit and the tire FEM model shape after the PCI process. A simulation apparatus is provided, including a grounding analysis calculator for calculating.

According to this configuration, the belt member is the only member whose physical property values are changed between the PCI analysis and the ground contact analysis. Therefore, the labor of redefining the analysis conditions is simplified. Among the physical properties, the elastic modulus generally takes a lower value as the temperature rises. Therefore, in the PCI analysis, it is preferable to set the modulus of elasticity of each member lower than the value at room temperature, and in the grounding analysis, set the modulus of elasticity of each member to the value at room temperature. However, it takes time and effort to redefine the physical property values of all members for each process. Therefore, focusing on the belt member that contributes greatly to the deformation, only the elastic modulus of the belt member is changed between the PCI process and the ground contact analysis, thereby simplifying the trouble of resetting the analysis conditions. In particular, the belt member contains a metal material, and has a lower temperature dependence of the elastic modulus than the rubber member forming the tread surface, the sidewall surface, and the like. Therefore, it can be said that the difference in elastic modulus between the belt member and the rubber member considering the temperature is large in the PCI analysis and small in the ground contact analysis. In the above configuration, instead of changing the elastic modulus of many rubber members arranged in each process, only the elastic modulus of the belt member is set higher than the elastic modulus at room temperature in the PCI process. difference relationship is preserved. Therefore, the contact analysis can be performed by reproducing the outer surface shape of the tire after the PCI process with high accuracy and ease.

The PCI analysis condition setting unit sets the elastic modulus of the end portion of 10 to 15% of the full width of the belt member to the normal temperature elastic modulus, and sets the elastic modulus of the portion other than the end portion of the belt member to the normal temperature elastic modulus. It may be set higher than the rate by a predetermined value or more.

According to this configuration, the deformation of the tread surface, which is less affected by PCI, is suppressed, and the sidewall surface, which is more affected by PCI, is deformed, so that a tire model that appropriately reproduces the influence of PCI can be obtained.

The PCI analysis condition setting unit may set the elastic modulus of the belt member to be twice or more higher than the elastic modulus at room temperature.

According to this configuration, deformation of the tread surface, which is less affected by PCI, can be further suppressed, so that the outer surface shape of the tire after the PCI process can be reproduced with higher accuracy.

A second aspect of the present invention acquires a tire FEM model obtained by dividing a tire having an outer surface shape corresponding to an inner surface shape of a vulcanization mold into a plurality of elements, and a PCI process performed immediately after vulcanization molding of the tire. and executing a contact analysis that reproduces the contact state of the tire after the PCI process, wherein the PCI analysis sets analysis conditions for the PCI analysis, and setting the analysis conditions includes setting the elastic modulus of the belt member higher than the elastic modulus at room temperature by a predetermined value or more, and calculating the shape of the tire FEM model after the PCI process based on the analysis conditions of the PCI analysis, wherein the contact analysis is , setting the analysis conditions for the ground contact analysis, and setting the same physical property values as the physical property values set as the analysis conditions for the PCI analysis for each member of the tire FEM model excluding the belt member in the setting of the analysis conditions; , setting the elastic modulus of the belt member to the elastic modulus of normal temperature, and calculating the tire contact performance based on the analysis conditions of the contact analysis and the tire FEM model shape after the PCI process. provide a way.

In the analysis conditions of the PCI analysis, the elastic modulus of the end portion of 10 to 15% of the total width of the belt member is set to the room temperature elastic modulus, and the elastic modulus of the portion other than the end portion of the belt member is set to the room temperature elastic modulus. It may be set higher than the rate by a predetermined value or more.

As for the analysis conditions for the PCI analysis, the elastic modulus of the belt member may be set to be two times or more higher than the elastic modulus at room temperature.

A third aspect of the present invention provides a program that, when loaded into a computer, causes the computer to execute any of the simulation methods described above.

ADVANTAGE OF THE INVENTION According to this invention, in a simulation apparatus, a simulation method, and a program, the tire outer shape after a PCI process can be reproduced highly accurately and simply, and a contact analysis can be performed.

Sectional drawing of a pneumatic tire. 1 is a block diagram of a simulation device according to one embodiment; FIG. Sectional drawing which shows the tire FEM model just after vulcanization molding. Sectional drawing which shows the outer surface shape of the tire FEM model before and after a PCI process. 4 is a flowchart of a simulation method of one embodiment; Sectional drawing which shows the tire FEM model immediately after vulcanization molding in a modification.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The simulation apparatus of the present embodiment is for highly accurate and easy ground contact analysis of pneumatic tires (hereinafter also simply referred to as tires) used in automobiles and the like. In particular, the simulation apparatus of this embodiment reproduces the shape of a tire that has undergone the PCI process, applies a predetermined internal pressure and a predetermined load to the tire thus reproduced, and grounds the tire on the road surface. and the force (ground pressure, etc.) generated on the ground contact surface.

FIG. 1 is a schematic tire meridional cross section of the tire 100 . Although FIG. 1 is a cross-sectional view, the hatching indicating the cross section is omitted in order to simplify the illustration.

Tire 100 includes tire body 110 and rim 120 .

The tire body 110 has a carcass 112 stretched between a pair of bead cores 111 and reinforced by a belt member 113 wound around the outer peripheral side of the intermediate portion of the carcass 112. A rubber material is provided on the outer side in the tire radial direction (direction A in the drawing). It has a configuration having a tread portion 114 made of. Sidewall portions 115 are continuous on both outer sides of the tread portion 114 in the tire width direction (direction B in the figure). A bead portion 116 is continuous with the inner side of the sidewall portion 115 in the tire radial direction. The tire body 110 is connected to the rim 120 at the bead portion 116 .

In the cross section shown in FIG. 1, the rim 120 extends inward in the tire radial direction between two flange portions 121 on which the two bead portions 116 of the tire body 110 are respectively arranged, and between the two flange portions 121 in the tire width direction. It has a concave portion 122 having a concave shape. The rim 120 can be made of metal such as aluminum alloy, magnesium alloy, or steel.

In the simulation apparatus of the present embodiment, the PCI process is considered in order to reproduce the outer surface shape of the tire 100, particularly the tire body 110, with high accuracy. In general, when conducting ground contact analysis of the tire 100, the outer surface shape of the tire body 110 is reproduced from the inner surface shape of a vulcanization mold (not shown). However, due to the PCI process performed after vulcanization, the outer surface shape of the tire body 110 expands slightly and becomes a different shape from the inner surface shape of the vulcanization mold. A simulation apparatus according to this embodiment, which performs contact analysis of the tire 100 in consideration of the PCI process, will be described below.

Referring to FIG. 2, simulation apparatus 1 of the present embodiment is a computer, and includes input unit 10 , display unit 20 , storage unit 30 , and control unit (processor) 40 .

The input unit 10 is a part that generates or receives input data for the simulation device 1, and is configured by, for example, a keyboard, a mouse, a touch panel, and the like. The user can input various conditions and data regarding analysis via the input unit 10 .

The display unit 20 is a part that displays the processing results of the control unit 40 and the like, and is configured by, for example, a liquid crystal display, an organic EL display, a plasma display, or the like.

The storage unit 30 stores programs that run on the control unit 40, data necessary for model generation for analysis, and the like.

The control unit 40 includes an FEM modeling unit 41 that creates an FEM (Finite Element Method) model of a tire, a PCI analysis unit 42 that performs PCI analysis, and a contact analysis unit 43 that performs contact analysis. These are realized through cooperation between a processor, which is a hardware resource, and a program, which is software recorded in the storage unit 30 or the like.

The FEM modeling unit 41 acquires a tire FEM model M3 (see FIG. 3) obtained by dividing a tire having an outer surface shape corresponding to the inner surface shape of a vulcanization mold (not shown) into a plurality of elements.

The PCI analysis unit 42 executes PCI analysis that reproduces the PCI process that is performed immediately after tire vulcanization. The PCI analysis section 42 includes a PCI analysis condition setting section 42a and a PCI analysis calculation section 42b.

The PCI analysis condition setting unit 42a is a part for setting analysis conditions for PCI analysis. For example, the physical property values of each member and various boundary conditions are set by the PCI analysis condition setting unit 42a. In particular, the elastic modulus of the belt member 113 (see FIG. 3) is set higher than the elastic modulus at normal temperature by a predetermined value or more, and the elastic moduli of the other members are set at the normal elastic modulus. Preferably, the PCI analysis condition setting unit 42a sets the elastic modulus of the belt member 113 to be twice or more higher than the elastic modulus at room temperature. More preferably, the PCI analysis condition setting unit 42a sets the elastic modulus of the belt member 113 to be ten times or more higher than the elastic modulus at room temperature. These elastic modulus settings may be determined according to the type of rubber member such as the tread portion 114 .

The PCI analysis calculation unit 42b calculates the shape of the tire FEM model M3 (see FIG. 3) after the PCI process based on the analysis conditions set by the PCI analysis condition setting unit 42a. In order to reproduce the PCI process, the PCI analysis calculation unit 42b deforms the tire FEM model M3 by applying internal pressure with the bead portion restrained. As a result, the outer surface shape of the tire FEM model M3 shown in FIG. 3 expands slightly like the outer surface shape of the tire FEM model M4 shown in FIG. In particular, since the elastic modulus of the belt member 113 is set high, the expansion amount is small in the tread portion 114 and large in the sidewall portion 115 (particularly the shoulder portion). Then, the calculated outer surface shape of the tire FEM model M4 after the PCI process is used as the shape in the natural state, and the contact analysis is performed as follows.

The ground contact analysis unit 43 performs a ground contact analysis that reproduces the ground contact state of the tire after the PCI process. The contact analysis section 43 includes a contact analysis condition setting section 43a and a contact analysis calculation section 43b.

The contact analysis condition setting section 43a is a part for setting contact analysis conditions. For example, the physical properties of each member and various boundary conditions are set by the ground analysis condition setting unit 43a. In particular, referring to FIGS. 3 and 4 together, for each member except the belt member 113 (not shown in FIG. 4) of the tire FEM model M4, the same physical property value as the physical property value set by the PCI analysis condition setting unit 42a is set, and the elastic modulus of the belt member 113 is set to the room temperature elastic modulus. Then, the tire FEM model M4 after the PCI process is assumed to have a natural shape, and boundary conditions are set so that the model M4 is applied with a predetermined internal pressure and a predetermined load so as to be brought into contact with the road surface. In addition, in FIG. 4, in order to clarify the illustration, only the outer surface shape of the tire FEM models M3 and M4 is shown, and the illustration of the internal constituent members is omitted.

The contact analysis calculation unit 43b calculates the contact performance of the tire based on the analysis conditions set by the contact analysis condition setting unit 43a and the shape of the tire FEM model M4 after the PCI process. In calculating the contact performance of the tire, contact shape, contact pressure, etc. are calculated.

By accurately predicting the ground contact shape and contact pressure distribution, it is possible to accurately predict tire rolling resistance, wear, durability, steering stability, vibration ride comfort, wet characteristics, and noise characteristics. .

A simulation method executed by the simulation apparatus of this embodiment will be described with reference to FIG.

When the simulation method of this embodiment is started (step S1), the tire FEM model M3 (see FIG. 3) is obtained by the FEM modeling section 41 (step S2). This tire FEM model M3 is obtained by dividing a tire having an outer surface shape corresponding to an inner surface shape of a vulcanization mold (not shown) into a plurality of elements as described above. The shape data of a tire having an outer surface shape corresponding to the inner surface shape of the vulcanization mold may be input via the input unit 10 or stored in the storage unit 30 in advance.

Next, the PCI analysis condition setting unit 42a sets analysis conditions such as physical property values of each member and various boundary conditions in the PCI analysis (step S3). In particular, the elastic modulus of the belt member 113 is set higher than the elastic modulus at normal temperature by a predetermined value or more, and the elastic moduli of the other members are set at the normal elastic modulus. In this embodiment, the elastic modulus of the belt member 113 is set to be ten times higher than the elastic modulus at room temperature. Then, a predetermined internal pressure is applied to the tire FEM model M3 while the bead portion is restrained. The analysis conditions here may be input via the input unit 10 or may be stored in the storage unit 30 in advance.

Next, the shape of the tire FEM model M3 after the PCI process is calculated by the PCI analysis calculation section 42b based on the analysis conditions set by the PCI analysis condition setting section 42a (step S4). As a result of deformation of the tire FEM model M3 to a state where the internal pressure set by the PCI analysis condition setting unit 42a and the reaction force generated by the deformation are balanced, the tire FEM model M4 after deformation through the PCI process (Fig. 4 ) is obtained.

Next, the analysis conditions for the ground analysis are set by the ground analysis condition setting unit 43a (step S5). Here, the shape of the tire FEM model M4 after being deformed by the application of internal pressure in the PCI analysis is taken as the shape of the natural state. In particular, the same physical property values as the physical property values set in the PCI analysis condition setting unit 42a are set for each member except the belt member 113 of the tire FEM model M4, and the elastic modulus of the belt member 113 is the elastic modulus at room temperature. set. Then, analysis conditions are set so that a predetermined internal pressure and a predetermined load are applied to the tire FEM model M4 so that the tire FEM model M4 is grounded on the road surface. The analysis conditions here may be input via the input unit 10 or may be stored in the storage unit 30 in advance.

Next, the ground contact performance of the tire is calculated by the contact analysis calculation section 43b based on the analysis conditions set by the contact analysis condition setting section 43a and the shape of the tire FEM model M4 after the PCI process (step S6). In calculating the contact performance of the tire, contact shape, contact pressure, etc. are calculated. Then, these analysis results are output to the display unit 20 (step S7), and the analysis ends (step S8).

According to this embodiment, the following effects are obtained.

The belt member 113 (see FIG. 1) is the only member whose physical property values are changed between the PCI analysis and the ground contact analysis. Therefore, the labor of redefining the analysis conditions is simplified. Among the physical properties, the elastic modulus generally takes a lower value as the temperature rises. Therefore, in the PCI analysis, it is preferable to set the modulus of elasticity of each member lower than the value at room temperature, and in the grounding analysis, set the modulus of elasticity of each member to the value at room temperature. However, it takes time and effort to redefine the physical property values of all members for each process. Therefore, focusing on the belt member 113 that contributes greatly to the deformation, only the elastic modulus of the belt member 113 is changed between the PCI process and the contact analysis, thereby simplifying the trouble of resetting the analysis conditions. In particular, the belt member 113 contains a metal material, and has lower temperature dependence of the elastic modulus than the rubber member forming the tread surface 114a, the sidewall surface 115a, and the like. Therefore, it can be said that the difference in elastic modulus between the belt member 113 and the rubber member considering the temperature is large in the PCI analysis and small in the contact analysis. In the present embodiment, instead of changing the elastic modulus of many rubber members arranged for each process, only the elastic modulus of the belt member 113 is set higher than the elastic modulus at normal temperature in the PCI process, thereby achieving the above-mentioned. The relation of elastic modulus difference is preserved. Therefore, the contact analysis can be performed by reproducing the outer surface shape of the tire after the PCI process with high accuracy and ease.

In addition, since the deformation of the tread surface 114a, which is less affected by PCI, can be further suppressed, the outer surface shape of the tire after the PCI process can be reproduced with higher accuracy.

(Modification)
Referring to FIG. 6, as a modification of the above-described embodiment, PCI analysis condition setting unit 42a (see FIG. 2) sets the edge of 10 to 15% of the total width of belt member 113 in the tire width direction (direction B in the figure). The modulus of elasticity of the portion 113a may be set to the modulus of elasticity at room temperature, and the modulus of elasticity of the portion (central portion 113b) of the belt member 113 other than the end portions 113a may be set higher than the modulus of elasticity at room temperature by a predetermined value. In other words, the PCI analysis condition setting unit 42a sets only the elastic modulus of the central portion 113b of the belt member 113 to be higher than the elastic modulus at room temperature by a predetermined value or more. Preferably, only the elastic modulus of the central portion 113b of the belt member 113 is set to be ten times or more higher than the elastic modulus at room temperature. The modulus of elasticity of each member other than the end portion 113a of the belt member 113 and the belt member 113 is set to the modulus of elasticity at room temperature.

According to this modification, deformation of the tread surface 114a, which is less affected by PCI, is suppressed, and sidewall surface 115a, which is more affected by PCI, is deformed. ) can be obtained.

As described above, specific embodiments and modifications thereof of the present invention have been described, but the present invention is not limited to the above embodiments, and various changes can be made within the scope of the present invention.

1 simulation device 10 input unit 20 display unit 30 storage unit 40 control unit (processor)
41 FEM modeling unit 42 PCI analysis unit 42a PCI analysis condition setting unit 42b PCI analysis calculation unit 43 Contact analysis unit 43a Contact analysis condition setting unit 43b Contact analysis calculation unit 100 Pneumatic tire (tire)
110 tire body 111 bead core 112 carcass 113 belt member 113a end 113b central portion 114 tread portion 114a tread surface 115 sidewall portion 115a sidewall surface 116 bead portion 120 rim 121 flange portion 122 concave portion M3, M4 tire FEM model

Claims (7)

an FEM modeling unit that obtains a tire FEM model obtained by dividing a tire having an outer surface shape corresponding to an inner surface shape of a vulcanization mold into a plurality of elements;
a PCI analysis unit that performs PCI analysis that reproduces the PCI process performed immediately after vulcanization molding of the tire;
a contact analysis unit that performs a contact analysis that reproduces the contact state of the tire after the PCI process,
The PCI analysis unit
a PCI analysis condition setting unit for setting the analysis conditions of the PCI analysis, the setting of the analysis conditions including setting the elastic modulus of the belt member higher than the elastic modulus at room temperature by a predetermined value or more;
a PCI analysis calculation unit that calculates the shape of the tire FEM model after the PCI process based on the analysis conditions set by the PCI analysis condition setting unit;
The ground analysis unit
A portion for setting the analysis conditions of the ground contact analysis, and the setting of the analysis conditions is the same physical property value as the physical property value set in the PCI analysis condition setting unit for each member except the belt member of the tire FEM model. and setting the elastic modulus of the belt member to the elastic modulus at room temperature;
a contact analysis calculation unit that calculates the contact performance of the tire based on the analysis conditions set by the contact analysis condition setting unit and the tire FEM model shape after the PCI process. The PCI analysis condition setting unit sets the elastic modulus of the end portion of 10 to 15% of the full width of the belt member to the normal temperature elastic modulus, and sets the elastic modulus of the portion other than the end portion of the belt member to the normal temperature elastic modulus. 2. The simulation apparatus according to claim 1, wherein the rate is set higher than the rate by a predetermined value or more. 3. The simulation apparatus according to claim 1, wherein said PCI analysis condition setting unit sets the elastic modulus of said belt member to be at least two times higher than the elastic modulus at room temperature. Acquiring a tire FEM model in which a tire having an outer surface shape corresponding to the inner surface shape of a vulcanization mold is divided into a plurality of elements,
Perform PCI analysis that reproduces the PCI process performed immediately after vulcanization molding of the tire,
including executing a contact analysis that reproduces the contact state of the tire after the PCI process,
The PCI analysis is
setting the analysis conditions for the PCI analysis, and setting the elastic modulus of the belt member higher than the elastic modulus at room temperature by a predetermined value or more in the setting of the analysis conditions;
calculating the post-PCI shape of the tire FEM model based on the analysis conditions of the PCI analysis;
The ground analysis includes:
The analysis conditions for the ground contact analysis are set, and in the setting of the analysis conditions, the same physical property values as the physical property values set as the analysis conditions for the PCI analysis are set for each member of the tire FEM model excluding the belt member, setting the elastic modulus of the belt member to a room temperature elastic modulus;
a simulation method comprising: calculating the tire contact performance based on the analysis conditions of the contact analysis and the tire FEM model shape after the PCI process. In the analysis conditions of the PCI analysis, the elastic modulus of the end portion of 10 to 15% of the total width of the belt member is set to the room temperature elastic modulus, and the elastic modulus of the portion other than the end portion of the belt member is set to the room temperature elastic modulus. 5. The simulation method according to claim 4, wherein the rate is set higher than the rate by a predetermined value or more. 6. The simulation method according to claim 4, wherein the analysis condition for said PCI analysis is to set the elastic modulus of said belt member to be at least twice as high as the elastic modulus at room temperature. A program that is loaded into a computer to cause the computer to execute the simulation method according to any one of claims 4 to 6.

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