JP2018079789A - Tire ground contact simulation method, device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire ground contact simulation method which reproduces influence due to PCI treatment.SOLUTION: This method includes: a step ST1 at which a tire FEM model, which has a main groove and a land part partitioned by the main groove at a tread part, is acquired; a step ST6 at which inner pressure filling processing for applying an inner pressure in the state that a bead part is arrested and deforming the tire FEM model is executed; a step ST7 at which the tire FEM model is so corrected that a shape thereof after deformation by application of the inner pressure is changed into a shape in the natural state that the inner pressure is not applied; and a ground contact analysis processing step at which a prescribed inner pressure and a prescribed load are applied to the tire FEM model after correction thereby causing the model to contact a road surface, and a ground contact shape and a force generated in a contact area are calculated. In the inner pressure filling processing, all nodal points, which constitute a tread face of the land part, are arrested and an inner pressure is applied (ST4) in the case that there is the land part on a tire equator (ST3: YES), and all nodal points, which constitute tread faces of two land parts adjacent to both sides of the main groove, are arrested and an inner pressure is applied (ST5) in the case that there is the main groove on the tire equator CL (ST3: NO).SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a tire ground contact simulation method, apparatus, and program.

  A tire characteristic is predicted using an FEM (Finite Element Method) model obtained by dividing a pneumatic tire into a plurality of finite elements. The outer surface of a tire model often adopts the inner shape of a mold for vulcanizing the tire as it is.

  When actually manufacturing a tire, a post that stabilizes the shape of the tire by cooling it while applying internal pressure to the inner surface of the tire instead of cooling the tire in a high temperature state taken out from the vulcanization mold as it is Cure inflation (PCI; Post Cure Inflation) processing is performed. Therefore, the cross-sectional shape of the tire is influenced not only by the shape of the inner surface of the vulcanization mold but also by the PCI treatment.

  Therefore, in Patent Document 1, in order to cope with a high temperature state, the elastic constant of a part of the tire model (for example, carcass) is set lower than the set value at normal temperature, and the internal pressure is set in a state where the bead portion is constrained. It is described that the tire is deformed by applying and the shape after deformation is adopted.

Japanese Patent Laid-Open No. 2004-217075

  However, in the method described in the above document, for example, the tire is deformed by filling with an internal pressure in a state where the elastic constant such as carcass is lowered. However, there is a possibility that the portion affected by the PCI processing may be deformed. In this case, since the actual tire has a different shape, the tire performance may not be accurately predicted.

  This indication was made paying attention to such a subject, and the object is to provide the tire contact simulation method, device, and computer program which reproduced appropriately the influence by PCI processing.

  In order to achieve the above object, the present disclosure takes the following measures.

  The tire contact simulation method of the present disclosure is a model to be subjected to contact analysis, a step of obtaining a tire FEM model having a main groove and a land portion partitioned by the main groove in a tread portion, and a state in which a bead portion is constrained The step of executing the internal pressure filling process for deforming the tire FEM model by applying the internal pressure in step S1 and the shape after being deformed by the application of the internal pressure are corrected to the tire FEM model having a shape in a natural state where the internal pressure is not applied. And a grounding analysis processing step of applying a predetermined internal pressure and a predetermined load to the road surface by applying a predetermined internal pressure and a predetermined load to the modified tire FEM model, and calculating a grounding shape and a force generated on the grounding surface under a predetermined boundary condition, In the internal pressure filling process, if there is a land part on the tire equator, the internal pressure is applied by restraining all nodes constituting the tread of the land part. In the case where there is a main groove imparts pressure to restrain all the nodes constituting the tread of the two land portions adjacent to both sides of the main groove.

  The tire ground contact simulation device according to the present disclosure is a model to be subjected to a ground contact analysis, and includes a model acquisition unit that acquires a tire FEM model having a main groove and a land portion partitioned by the main groove in a tread portion, and a bead portion is restrained. An internal pressure filling processing unit for executing an internal pressure filling process for deforming the tire FEM model by applying an internal pressure in a state of being applied, and a tire having a shape after being deformed by the application of the internal pressure as a shape in a natural state where no internal pressure is applied A model correction unit that corrects the FEM model, and a ground analysis that calculates a ground contact shape and a force generated on the contact surface under a predetermined boundary condition by applying a predetermined internal pressure and a predetermined load to the corrected tire FEM model to contact the road surface. In the internal pressure filling process, when there is a land portion on the tire equator, the internal pressure is applied by restraining all nodes constituting the tread of the land portion, If there is a main groove in the tire equator, it imparts pressure to restrain all the nodes constituting the tread of the two land portions adjacent to both sides of the main groove.

  In this way, the center portion of the tread portion that is less affected by PCI can be deformed only from the shoulder portion to the side portion, and a tire model that appropriately reproduces the influence of PCI can be obtained. It becomes possible, and it becomes possible to improve the result of grounding analysis. Further, since all the nodes constituting the tread of the land portion to be restrained are restrained, the shape of the tread can be prevented from becoming discontinuous.

1 is a block diagram illustrating an apparatus according to the present disclosure. The flowchart which shows the model correction process routine which an apparatus performs. The figure which shows the model before correction. The figure which shows the model after correction. The comparison figure which shows the model of the model before correction, the model after correction, and an actual tire. The figure which shows a grounding analysis result. The figure which shows the example of restraint of the tread of this indication. The figure which shows the example of restraint of the tread of this indication. The figure which shows the example of restraint of the tread of this indication.

  Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[Tire contact simulation device (tire contact analysis device)]
The ground contact analysis device 1 ′ has a tire model correction device 1, which applies a predetermined internal pressure and a predetermined load to the corrected tire FEM model to make contact with the road surface. Calculate force (such as contact pressure).

[Tire model correction device]
The device 1 modifies the tire model. Specifically, as illustrated in FIG. 1, the device 1 includes a model acquisition unit 10, a processing unit 11, and a model correction unit 12. These units 10 to 12 are realized by cooperation of software and hardware by executing a processing routine (not shown) stored in advance by the CPU in an information processing apparatus such as a personal computer equipped with a CPU, memory, various interfaces, and the like. Is done.

  The apparatus 1 accepts an operation from a user via a known operation unit such as a keyboard or a mouse, accepts data regarding tire processing target tire data and data regarding PCI processing conditions (internal pressure, restraint position), Is stored in the memory.

  The model acquisition unit 10 illustrated in FIG. 1 generates or acquires a tire FEM model. As shown in FIG. 3, it is an axially symmetric model that is rotationally symmetric about the tire axis, and is defined by a tire meridian cross section. The model M0 is formed of tire constituent members such as a carcass ply, a bead core, a bead filler, a sidewall rubber, and a tread rubber, and a finite element model is set for deformation analysis. In the tread portion 3, a main groove 30 and a land portion 31 partitioned by the main groove 30 are defined. All nodes constituting the tread in the land are set as grounding candidate points. A contact point with the rim is defined around the bead portion 2, and the contact point with the rim is constrained during the internal pressure filling process (nodes connected to triangles in the figure mean constraining). ). Further, in the model M0, an internal pressure application point at which an internal pressure is applied is defined on the inner liner (a node indicated by an arrow in the figure). The physical properties of the members are set for the members constituting the model M0.

  When the land portion 31 is present on the tire equator CL, the internal pressure filling processing unit 11 shown in FIG. 1 constrains all nodes constituting the tread of the land portion 31 to apply internal pressure, and mainly applies the tire equator CL to the tire equator CL. When the groove 30 is present, the internal pressure is applied by restraining all the nodes constituting the treads of the two land portions 31 adjacent to both sides of the main groove 30. The example of FIG. 3 is an example in which the main groove 30 is in the tire equator CL, and the two main grooves adjacent to the main groove 30 passing through the tire equator CL are shown in FIG. All nodes constituting the tread surface of the groove 30 are restrained. The example of FIG. 3 is a half cross section, but when shown in an overall cross section, it becomes as shown in FIG. 7A. In the case of FIG. 7A, the land portions 1 and 2 are restrained. FIG. 7B shows an example in which there are five main grooves and the main groove 30 passes through the tire equator CL. In this case, the land portions 2 and 3 are restrained. FIG. 7C is an example in which a land portion is present on the tire equator CL. In this case, the land portion 2 is restrained.

  Of course, in the internal pressure filling process, all treads on the land portion between the pair of main grooves 30 ′ which are the outermost in the tire width direction may be constrained. In the example of FIG. 7A, land portions 1 and 2 are restrained. In the example of FIG. 7B, land portions 1, 2, 3, and 4 are restrained. In the example of FIG. 7C, the land portions 1, 2, and 3 are restrained. In this way, since the shoulder portion and the side portion are deformed while suppressing the deformation of the center portion, it is possible to obtain a tire model that appropriately reproduces the influence of PCI.

  The internal pressure filling processing unit 11 applies a predetermined internal pressure in the restrained state, and executes an internal pressure filling process for deforming the tire FEM model as shown in FIGS. 3 and 4. The tire is deformed by the application of the internal pressure, and the tire is deformed to a state where the reaction force generated by the deformation, the internal pressure, and the force can be balanced.

  As shown in FIG. 4, the model correction unit 12 shown in FIG. 1 corrects the shape after being deformed by the application of the internal pressure into a tire FEM model M1 having a natural state shape where no internal pressure is applied. It can be simply corrected by moving the node from the model M0. FIG. 5 shows the shape of the actual tire T subjected to the PCI treatment, the shape of the tire FEM model M0 based on the inner surface of the mold, and the tire FEM model deformed by applying an internal pressure corresponding to the PCI treatment to the tire FEM model M0. It is a figure which shows the shape of M1. In the upper part of FIG. 5, a large difference between the actual tire T and the tire model M0 is seen in the shoulder portion. In the lower part of FIG. 5, it can be seen that the difference between the actual tire T and the tire model M1 is reduced in the shoulder portion.

  For the tire FEM model M0 and the model M1 modified according to the present disclosure, the ground contact shape of the tire was simulated using the ground contact analysis device 1 'shown in FIG. The ground analysis device 1 ′ has a ground analysis execution unit 13. The ground contact analysis execution unit 13 applies a predetermined internal pressure to the model under a predetermined boundary condition, applies a predetermined load to the virtual road surface, and calculates a ground shape and a ground pressure.

  FIG. 6 shows the ground contact shape as an analysis result. As shown in FIG. 6, the upper part is actual measurement, the middle part is a comparative example using the model M0, and the lower part is an embodiment using the model M1. The contact length ratio (Sh / Ce) between the shoulder portion and the center portion was 1.05 for the actual measurement, 0.774 for the comparative example, and 1.008 for the example. The ground contact width was 118.7 for actual measurement, 117.0 for comparative example, and 118.0 for example. In any case, the example is closer to the actually measured value than the comparative example. Therefore, it turns out that this method is effective.

[How to fix]
The operation of the apparatus 1 will be described with reference to FIGS.

  First, in step ST <b> 1, the model acquisition unit 10 acquires a tire FEM model M <b> 0 having a main groove 30 and a land portion 31 partitioned by the main groove 30 in the tread portion 3.

  In next step ST <b> 2, the internal pressure filling processing unit 11 restrains the bead unit 2. In the next step ST3, the internal pressure filling processing unit 11 determines whether or not the land portion 31 is on the tire equator CL, and restrains the tread of the land portion 31 when the land portion 31 is on the tire equator CL. (Step ST4). On the other hand, when the tire equator CL does not have the land portion 31 and the tire equator CL has the main groove 30, the treads of the two land portions 31 adjacent to both sides of the main groove 30 are restrained (step ST5).

  In the next step ST6, the internal pressure filling unit 11 applies a predetermined internal pressure to deform the tire FEM model M0.

  In the next step ST7, the model correction unit 12 corrects the shape after being deformed by the application of the internal pressure to a model M1 that has a natural state shape.

  As described above, the tire ground contact simulation method of the present embodiment is a model to be subjected to ground contact analysis, and includes the tire FEM model M0 having the main groove 30 and the land portion 31 partitioned by the main groove 30 in the tread portion 3. A step (ST1) of acquiring, a step (ST6) of executing an internal pressure filling process for deforming the tire FEM model M0 by applying an internal pressure while the bead portion 2 is constrained, and a shape after being deformed by the application of the internal pressure. A step (ST7) of correcting the tire FEM model M1 in a natural state to which no internal pressure is applied, and applying a predetermined internal pressure and a predetermined load to the corrected tire FEM model M1 to make contact with the road surface. And a grounding analysis processing step for calculating a force generated on the grounding shape and the grounding surface. In the internal pressure filling process, when there is a land portion 31 on the tire equator CL (ST3: YES), all the nodes constituting the tread of the land portion 31 are restrained to apply internal pressure (ST4), and the tire equator CL is applied to the tire equator CL. When there is the main groove 30 (ST3: NO), all the nodes constituting the treads of the two land portions adjacent to both sides of the main groove 30 are restrained to apply the internal pressure (ST5).

  The tire contact simulation device of this embodiment is a model that is a model to be subjected to contact analysis, and acquires a tire FEM model M0 having a main groove 30 and a land portion 31 partitioned by the main groove 30 in the tread portion 3. 10 and an internal pressure filling processing unit 11 for executing an internal pressure filling process for deforming the tire FEM model M0 by applying an internal pressure in a state in which the bead part 2 is constrained, and a shape after being deformed by the application of the internal pressure. A model correction unit 12 that corrects the tire FEM model M1 in a natural state that has not been made, and a ground contact shape that is subjected to a predetermined internal pressure and a predetermined load on the corrected tire FEM model and applied to the road surface under a predetermined boundary condition And a grounding analysis execution unit 13 for calculating a force generated on the grounding surface. In the internal pressure filling process, when there is a land portion 31 on the tire equator CL, all the nodes constituting the tread surface of the land portion 31 are restrained to apply internal pressure, and when the main groove 30 is present on the tire equator CL. The inner pressure is applied by restraining all the nodes constituting the treads of the two land portions adjacent to both sides of the main groove 30.

  In this way, the center portion of the tread portion that is less affected by PCI can be deformed only from the shoulder portion to the side portion, and a tire model that appropriately reproduces the influence of PCI can be obtained. It becomes possible, and it becomes possible to improve the result of grounding analysis. Further, since all the nodes constituting the tread of the land portion to be restrained are restrained, the shape of the tread can be prevented from becoming discontinuous.

  In the present embodiment, in the internal pressure filling process, the treads of all the land portions between the pair of main grooves (30 ', 30') on the outermost side in the tire width direction WD are restrained.

  In this way, since the shoulder portion and the side portion are deformed while suppressing the deformation of the center portion, it is possible to obtain a tire model that appropriately reproduces the influence of PCI.

The program according to the present embodiment causes a computer to execute each step constituting the method.
By executing these programs, it is possible to obtain the operational effects of the above method. In other words, it can be said that the above method is used.

  As mentioned above, although embodiment of this indication was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present disclosure is indicated not only by the above description of the embodiments but also by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, each of the units 10 to 12 illustrated in FIG. 1 is realized by executing a predetermined program by a CPU of a computer, but each unit may be configured by a dedicated memory or a dedicated circuit.

  The structure employed in each of the above embodiments can be employed in any other embodiment. The specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure.

DESCRIPTION OF SYMBOLS 3 ... Tread part 30 ... Main groove 31 ... Land part 10 ... Model acquisition part 11 ... Internal pressure filling process part 12 ... Model correction part 13 ... Grounding analysis execution part

Claims (5)

Obtaining a tire FEM model which is a model to be subjected to ground contact analysis and has a main groove and a land portion partitioned by the main groove in a tread portion;
Executing an internal pressure filling process of deforming the tire FEM model by applying an internal pressure in a state where the bead portion is constrained;
Correcting the shape after being deformed by the application of internal pressure to a tire FEM model having a shape in a natural state where no internal pressure is applied;
A grounding analysis processing step for applying a predetermined internal pressure and a predetermined load to the tire FEM model after correction to contact the road surface, and calculating a grounding shape and a force generated on the grounding surface under a predetermined boundary condition,
In the internal pressure filling process, when there is a land portion on the tire equator, the internal pressure is applied by restraining all nodes constituting the tread of the land portion, and when there is a main groove on the tire equator, A tire ground contact simulation method for applying an internal pressure by restraining all the nodes constituting the treads of two land portions adjacent to both sides of a groove.   2. The method according to claim 1, wherein in the internal pressure filling process, all nodes constituting the treads of all land portions between a pair of outermost main grooves in the tire width direction are restrained. A model acquisition unit for obtaining a tire FEM model having a land portion divided by a main groove and a main groove in a tread portion, which is a model to be subjected to ground contact analysis;
An internal pressure filling process unit for executing an internal pressure filling process for deforming the tire FEM model by applying an internal pressure in a state where the bead part is constrained;
A model correction unit that corrects the shape after being deformed by the application of the internal pressure into a tire FEM model having a shape in a natural state where no internal pressure is applied;
A grounding analysis execution unit that applies a predetermined internal pressure and a predetermined load to the modified tire FEM model to contact the road surface, and calculates a grounding shape and a force generated on the grounding surface under a predetermined boundary condition;
In the internal pressure filling process, when there is a land portion on the tire equator, the internal pressure is applied by restraining all nodes constituting the tread of the land portion, and when there is a main groove on the tire equator, A tire ground contact simulation device that applies internal pressure by restraining all the nodes constituting the treads of two land portions adjacent to both sides of a groove.   The apparatus according to claim 3, wherein in the internal pressure filling process, the treads of all land portions between a pair of outermost main grooves in the tire width direction are restrained.   The program which makes a computer perform the method of Claim 1 or 2.