JP6933532B2 - Tire FEM model generation method, equipment, and program - Google Patents

Description

The present disclosure relates to a method, an apparatus, and a program for generating a tire FEM model.

A tire characteristic is predicted by using a FEM (Finite Element Method) model in which a pneumatic tire is divided into a plurality of finite elements. For the outer surface of the tire model, the inner surface shape of the mold for vulcanizing the tire is often adopted as it is.

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

Therefore, in Patent Document 1, in order to cope with a high temperature state, the elastic constant of some members (for example, carcass) of the tire model is set lower than the set value at room temperature, and the internal pressure is applied while the bead portion is restrained. It is described that the tire is given to deform the tire and the deformed shape is adopted.

Japanese Unexamined Patent Publication No. 2004-217705

However, in the method described in the above document, for example, the tire is deformed by filling with internal pressure in a state where the elastic constant such as carcass is lowered, but there is a possibility that the tire is deformed to a portion where the influence of the PCI treatment is small. In this case, the shape of the tire is different from that of the actual tire, so that the tire performance may not be accurately predicted.

The present disclosure has focused on such issues, and an object of the present disclosure is to provide a method, an apparatus, and a program for generating a tire FEM model that appropriately reproduces the influence of PCI processing.

The present disclosure takes the following measures to achieve the above object.

The method for generating the tire FEM model of the present disclosure is as follows.
A tire FEM model in which a tire is represented by a plurality of elements, a carcass ply extending from a tread portion to a bead portion and having an elastic constant set, and a cord arranged outside the carcass ply in the radial direction in the tread portion. A step of acquiring a tire FEM model having a plurality of reinforcing members having a bead filler, a bead filler arranged in the bead portion, and a land portion partitioned by a main groove in the tread portion.
The elastic constant of at least a part of the carcass ply in the region from the portion corresponding to the outermost end in the width direction of the reinforcing member in the width direction to the portion corresponding to the tip of the bead filler is set to be larger than the original value. Steps to change to a lower value,
If there is a land part on the tire equator, set conditions to restrain all the nodes and the bead part that make up the tread of the land part, and if there is a main groove on the tire equator, both sides of the main groove. A step of setting all the nodes constituting the treads of the two land parts adjacent to the equator and the conditions for restraining the bead part, and
The step of executing the internal pressure filling process of deforming the tire FEM model by applying the internal pressure while maintaining the restrained state, and
A step of returning the elastic constant to the original value and modifying the shape after being deformed by applying the internal pressure to a tire FEM model in which the shape is in a natural state without applying the internal pressure.
including.

In this way, since the land area around the tire equator is restrained, the deformation around the tire equator, which is less affected by PCI, can be suppressed, and the tire can be deformed only from the shoulder part to the sidewall part, and the entire tread part is in the radial direction. It is possible to avoid bulging outward.
Further, the elastic constant (Young's modulus) of at least a part of the carcass ply from the portion corresponding to the outer end in the width direction of the reinforcing member to the portion corresponding to the tip of the bead filler is set to a value lower than the original value. Therefore, it is possible to obtain a tire model that appropriately reproduces the influence of PCI by making the sidewall portion easily deformed. Further, since all the nodes constituting the tread of the land to be restrained are restrained, it is possible to prevent the shape of the tread from becoming discontinuous.
Therefore, the shapes of the tread portion and the sidewall portion of the tire can be brought close to the shape of the tire after the PCI treatment, and a tire FEM model that appropriately reproduces the influence of the PCI treatment can be generated.

The block diagram which shows the apparatus which concerns on this disclosure. A flowchart showing a model generation processing routine executed by the device. The figure which shows the tire model. A comparison diagram showing the shape of the model before modification and the shape of the actual tire. The comparative figure which shows the shape of a model after restraining a tread surface and changing the elastic constant, and the shape of an actual tire. A comparative diagram showing the shape of the model after the modification by changing the elastic constant without restraining the tread and the shape of the actual tire.

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

[Tire FEM model generator]
Device 1 modifies the tire model. Specifically, as shown in FIG. 1, the device 1 includes a model acquisition unit 10, an elastic constant changing unit 11, a constraint condition setting unit 12, an internal pressure filling processing unit 13, and a model correction unit 14. .. Each of these units 10 to 14 is realized in cooperation with software and hardware by executing a processing routine (not shown) in which the CPU is stored in advance in an information processing device such as a personal computer equipped with a CPU, memory, various interfaces, and the like. Will be done.

The device 1 accepts operations from the user via a known operation unit such as a keyboard or mouse, and accepts data on the tire FEM model to be PCI processed and data on PCI processing conditions (internal pressure, restraint position). Store these data in memory.

The model acquisition unit 10 shown in FIG. 1 generates or acquires a tire FEM model. As shown in FIG. 3, the tire FEM model M0 is tire data used by the finite element method in which the tire is represented by a plurality of elements. Model M0 is axisymmetric and rotationally symmetric about the tire axis and is defined by the tire meridian cross section. The model M0 has a carcass ply 4b that reaches the bead portion 1 from the tread portion 3 through the sidewall portion 2 and has an elastic constant set, and a plurality of carcass ply 4b arranged outside the radial RD of the carcass ply 4b in the tread portion 3. It has a reinforcing member (belt 4c, belt reinforcing layer 4d), a bead filler 1a arranged in the bead portion 1, and a land portion 31 partitioned by a main groove 30 in the tread portion 3. The belt reinforcing layer 4d may be omitted. Physical property values such as elastic constants of the members are set for each member constituting the tire.

The elastic constant changing unit 11 shown in FIG. 1 changes a part of the elastic constant (Young's modulus) of the carcass ply 4b to a value lower than the original value. Specifically, as shown in FIG. 3, the region Ar1 from the portion P1 corresponding to the outermost end in the width direction of the reinforcing member (4d) on the outermost side in the width direction WD to the portion P2 corresponding to the tip of the bead filler 1a. The elastic constants of at least a part of the carcass ply 4b in the above are changed.

In the present embodiment, as shown in FIG. 3, the elastic constant changing portion 11 is the bead filler 1a from the portion P1 corresponding to the outermost end in the width direction of the reinforcing member (belt reinforcing layer 4d) on the outermost side in the width direction WD. The elastic constant of the carcass ply 4b in the entire region Ar1 up to the portion P2 corresponding to the tip is changed to a value lower than the original value, but the present invention is not limited to this.

For example, as shown in the figure, the elastic constant changing portion 11 corresponds to the tip of the bead filler 1a from the portion P1 corresponding to the outermost end in the width direction of the reinforcing member (belt reinforcing layer 4d) on the outermost side in the width direction WD. The length along the carcass ply 4b up to the part P2 is 100%, and at least 25% of the area Ar2 outward of the tire radial RD and 25% inside the tire radial RD centering on the part Max where the tire width is maximum. It is preferable to change the elastic constant of the carcass ply 4b in the region Ar3 to a value lower than the original value. This is because lowering the elastic constant of the carcass ply 4b in this region (Ar2, Ar3) is dominant in deforming the sidewall portion 2. On the other hand, of the carcass ply 4b, the portion overlapping the reinforcing member (belt 4c or the belt reinforcing layer 4d) and the portion on the bead portion 1 side of the tip of the bead filler 1a are not easily deformed, so that even if the elastic constant is changed, it is effective. This is because there are few.

When the tire equatorial CL has a land portion 31, the constraint condition setting unit 12 shown in FIG. 1 sets conditions for constraining all the nodes and the bead portion 1 constituting the tread surface of the land portion 31. FIG. 3 shows an example in which the tire equator CL has a main groove 30, and as shown by connecting the constraining nodes in the figure in a triangular shape, the two main grooves 30 adjacent to the main groove 30 passing through the tire equator CL are shown. Constrain all the nodes that make up the tread. A contact point with the rim is defined around the bead portion 1, and the contact point with the rim is constrained during the internal pressure filling process (the nodes connected in a triangle in the figure mean the restraint). ). Further, in the model M0, an internal pressure applying point to which the internal pressure is applied to the inner liner is defined.

Although not shown, when the tire equator has a main groove, the restraint condition setting unit 12 restrains all the nodes and the bead portion 1 constituting the treads of the two land portions adjacent to both sides of the main groove. Set the conditions to be used. Further, in the above example, only the land area near the tire equator CL is restrained, but
All land treads between the pair of main grooves on the outermost side of the tire width direction WD may be restrained.

The internal pressure filling processing unit 13 shown in FIG. 1 applies a predetermined internal pressure while maintaining the restrained state, and executes the internal pressure filling processing that deforms the tire FEM model M0. The tire is deformed by applying the internal pressure, and the tire is deformed to a state where the reaction force generated by the deformation and the internal pressure and the force can be balanced.

The model correction unit 14 shown in FIG. 1 returns the elastic constant to the original value and corrects the shape after being deformed by applying the internal pressure to the tire FEM model M1 having the shape in the natural state without applying the internal pressure. .. It can be easily modified by moving the node from the model M0.

FIG. 4 is a diagram showing an actual shape (solid line) of the tire T subjected to PCI processing and a shape (broken line) of the tire FEM model M0 based on the inner surface of the mold. In FIG. 4, a large difference between the actual tire T and the tire model M0 can be seen in the sidewall portion 2, and a slight difference can be confirmed in the shoulder portion Sh in the tread portion 3.

FIG. 5 shows the actual shape (solid line) of the tire T subjected to the PCI treatment and the method of the present disclosure (the elastic constant of the region Ar1 was changed and the land portion 31 was constrained) corresponding to the PCI treatment of the tire FEM model M0. It is a figure which shows the shape (broken line) of the tire FEM model M1 which was deformed by applying the internal pressure. In FIG. 5, it can be seen that the difference between the actual tire T and the tire model M1 is small in both the shoulder portion Sh and the sidewall portion 2.

FIG. 6 shows the shape (solid line) of the actual tire T subjected to PCI processing and the shape of the tire FEM model M2 obtained by the method of Patent Document 1 in which the elastic constant of the region Ar1 is changed but the land portion 31 is not constrained. (Dashed line) is a diagram showing. It can be seen that the difference between the actual tire T and the tire model M2 is small in the sidewall portion 2, but on the other hand, the difference between the actual tire T and the tire model M2 is large in the tread portion 3, especially the shoulder portion Sh. Be done. If the land portion 31 is not restrained, the tire model M2, particularly the shoulder portion Sh, has a shape in which it is raised upward (outward in the radial direction).

It is also possible to mount the ground contact analysis device using the modified tire FEM model M1. Specifically, under a predetermined boundary condition, a predetermined internal pressure and a predetermined load are applied to the modified tire FEM model M1 to bring it into contact with the virtual road surface, and the deformation of the tire FEM model due to the load, the contact shape, and the contact pressure are calculated. To do.

[How to generate a tire FEM model]
The operation of the device 1 will be described with reference to FIGS. 1 and 2.

First, in step ST1, the model acquisition unit 10 acquires the tire FEM model M0. The tire FEM model M0 is a tire FEM model M0 in which the tire is represented by a plurality of elements, and is a carcass ply 4b extending from the tread portion 3 to the bead portion 1 and having an elastic constant set, and a carcass ply 4b in the tread portion 3. A plurality of reinforcing members (belt 4c, belt reinforcing layer 4d) having a cord arranged outside the radial RD of the tire, a bead filler 1a arranged in the bead portion 1, and a main groove 30 in the tread portion 3 are partitioned. It has a land portion 31 and.

In the next step ST2, the elastic constant changing portion 11 is from the portion P1 corresponding to the outermost end in the width direction of the reinforcing member (belt reinforcing layer 4d) on the outermost side in the width direction WD to the portion P2 corresponding to the tip of the bead filler 1a. The elastic constant of at least a part of the carcass ply 4b in the region Ar1 is changed to a value lower than the original value.

In the next steps ST3 to 5, when the tire equator CL has the land portion 31, the constraint condition setting unit 12 sets the conditions for constraining all the nodes and the bead portion 1 constituting the tread surface of the land portion 31. (Step ST4) When the tire equator CL has a main groove 30, a condition for restraining all the nodes and the bead portion 1 constituting the treads of the two land portions 31 adjacent to both sides of the main groove 30 is set. (Step ST5).

Although steps ST3 to 5 are executed after step ST2, the order thereof is not limited to this. It is also possible to execute step ST2 after steps ST3-5.

In the next step ST6, the internal pressure filling processing unit 13 executes the internal pressure filling processing of applying the internal pressure while maintaining the restrained state to deform the tire FEM model M0.

In the next step ST7, the model correction unit 14 returns the elastic constant to the original value, and the shape after being deformed by applying the internal pressure is changed to the tire FEM model M1 in which the shape is in the natural state without applying the internal pressure. Fix it.

As described above, the method of generating the tire FEM model of the present embodiment is
A tire FEM model M0 in which a tire is represented by a plurality of elements, the carcass ply 4b extending from the tread portion 3 to the bead portion 1 and having an elastic constant set, and the tread portion 3 outside the radial RD of the carcass ply 4b. A plurality of reinforcing members (belt 4c, belt reinforcing layer 4d) having a cord to be arranged, a bead filler 1a arranged in the bead portion 1, and a land portion 31 partitioned by a main groove 30 in the tread portion 3 are provided. Step (ST1) to acquire the tire FEM model M0 to have,
At least a part of the carcass ply 4b in the region Ar1 from the portion P1 corresponding to the outermost end in the width direction of the reinforcing member (belt reinforcing layer 4d) on the outermost side of the width direction WD to the portion P2 corresponding to the tip of the bead filler 1a. In the step (ST2) of changing the elastic constant to a value lower than the original value,
When the tire equatorial CL has a land portion 31, conditions for restraining all the nodes and the bead portion 1 constituting the tread of the land portion 31 are set, and when the tire equatorial CL has a main groove 30, the main groove 30 is set. Steps (ST3 to 5) for setting conditions for restraining all the nodes and bead portions 1 constituting the treads of the two land portions 31 adjacent to both sides of the groove 30.
The step (ST6) of executing the internal pressure filling process of deforming the tire FEM model M0 by applying the internal pressure while maintaining the restrained state, and
A step (ST7) of returning the elastic constant to the original value and modifying the shape after being deformed by applying the internal pressure to the tire FEM model M1 having the shape in the natural state without applying the internal pressure.
including.

The tire FEM model generator of the present embodiment is
A tire FEM model M0 in which a tire is represented by a plurality of elements, the carcass ply 4b extending from the tread portion 3 to the bead portion 1 and having an elastic constant set, and the tread portion 3 outside the radial RD of the carcass ply 4b. A plurality of reinforcing members (belt 4c, belt reinforcing layer 4d) having a cord to be arranged, a bead filler 1a arranged in the bead portion 1, and a land portion 31 partitioned by a main groove 30 in the tread portion 3 are provided. The model acquisition unit 10 for acquiring the tire FEM model M0 to have, and
At least a part of the carcass ply 4b in the region Ar1 from the portion P1 corresponding to the outermost end in the width direction of the reinforcing member (belt reinforcing layer 4d) on the outermost side of the width direction WD to the portion P2 corresponding to the tip of the bead filler 1a. The elastic constant changing unit 11 that changes the elastic constant to a value lower than the original value,
When the tire equatorial CL has a land portion 31, conditions for restraining all the nodes and the bead portion 1 constituting the tread of the land portion 31 are set, and when the tire equatorial CL has a main groove 30, the main groove 30 is set. A constraint condition setting unit 12 for setting conditions for constraining all the nodes and the bead portion 1 constituting the treads of the two land portions 31 adjacent to both sides of the groove 30.
Internal pressure filling processing unit 13 that executes internal pressure filling processing that deforms the tire FEM model M0 by applying internal pressure while maintaining the restrained state, and
A model correction unit 14 that returns the elastic constant to the original value and corrects the shape after being deformed by applying the internal pressure to the tire FEM model M1 that has the shape in the natural state without applying the internal pressure.
To be equipped.

In this way, since the land portion 31 around the tire equator is restrained, the deformation around the tire equator CL, which is less affected by PCI, can be suppressed, and the deformation can be performed only from the shoulder portion Sh to the sidewall portion 2, and the tread portion can be deformed. It is possible to prevent the entire 3 from bulging outward in the radial direction.
Further, in the carcass ply, at least a part of the elastic constant (Young's modulus) of the region Ar1 from the portion P1 corresponding to the outer end in the width direction of the reinforcing member to the portion P2 corresponding to the tip of the bead filler 1a is larger than the original value. Since it is set to a low value, it is possible to easily deform the sidewall portion 2 and obtain a tire model that appropriately reproduces the influence of PCI. Further, since all the nodes constituting the tread surface of the land portion 31 to be restrained are restrained, it is possible to prevent the shape of the tread surface from becoming discontinuous.
Therefore, the shapes of the tread portion 3 and the sidewall portion 2 of the tire can be brought close to the shape of the tire after the PCI treatment, and a tire FEM model that appropriately reproduces the influence of the PCI treatment can be generated.

In the present embodiment, the elastic constant changing portion 11 extends from a portion P1 corresponding to the outermost end in the width direction of the reinforcing member (belt reinforcing layer 4d) on the outermost side in the width direction WD to a portion P2 corresponding to the tip of the bead filler 1a. The length along the carcass ply 4b is set to 100%, and at least in the region Ar2 of 25% outward of the tire radial RD and the region Ar3 of 25% inward of the tire radial RD centering on the portion Max where the tire width is maximum. The elastic constant of the carcass ply 4b is changed to a value lower than the original value (step ST2).

This is because the elastic constants of ± 25% of the regions Ar2 and Ar3 centered on the region Max where the tire width is maximum are dominant in deforming the sidewall portion 2.

In the present embodiment, the elastic constant changing portion 11 extends from a portion P1 corresponding to the outermost end in the width direction of the reinforcing member (belt reinforcing layer 4d) on the outermost side in the width direction WD to a portion P2 corresponding to the tip of the bead filler 1a. The elastic constant of the carcass ply 4b in the entire region Ar1 is changed to a value lower than the original value (step ST2).

In this way, the tire sidewall portion can be accurately deformed and the influence of PCI can be appropriately reproduced.

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

Although the embodiments of the present disclosure have been described above with reference to the drawings, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present disclosure is shown not only by the description of the above-described embodiment but also by the scope of claims, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

For example, the execution order of each process such as operation, procedure, step, and step in the device, system, program, and method shown in the claims, specification, and drawings may be the output of the previous process after the output. Unless used in processing, it can be realized in any order. Even if the claims, the specification, and the flow in the drawings are explained using "first", "next", etc. for convenience, it does not mean that it is essential to execute in this order. ..

For example, although each unit 10 to 14 shown in FIG. 1 is realized by executing a predetermined program on the CPU of the computer, each unit may be configured by a dedicated memory or a dedicated circuit.

It is possible to adopt the structure adopted in each of the above embodiments in any other embodiment. The specific configuration of each part is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present disclosure.

1 ... bead part 1a ... bead filler 10 ... model acquisition part 11 ... elastic constant changing part 12 ... constraint condition setting part 13 ... internal pressure filling processing part 14 ... model correction part 3 ... tread part 30 ... main groove 31 ... land part 4b ... Carcass ply 4c ... Belt (reinforcing member)
4d ... Belt reinforcement layer (reinforcement member)
M0 ... Tire FEM model

Claims (7)

The way the computer does
A tire FEM model in which a tire is represented by a plurality of elements, a carcass ply extending from a tread portion to a bead portion and having an elastic constant set, and a cord arranged outside the carcass ply in the radial direction in the tread portion. A step of acquiring a tire FEM model having a plurality of reinforcing members having a bead filler, a bead filler arranged in the bead portion, and a land portion partitioned by a main groove in the tread portion.
The elastic constant of at least a part of the carcass ply in the region from the portion corresponding to the outermost end in the width direction of the reinforcing member in the width direction to the portion corresponding to the tip of the bead filler is set to be larger than the original value. Steps to change to a lower value,
If there is a land part on the tire equator, set conditions to restrain all the nodes and the bead part that make up the tread of the land part, and if there is a main groove on the tire equator, both sides of the main groove. A step of setting all the nodes constituting the treads of the two land parts adjacent to the equator and the conditions for restraining the bead part, and
The step of executing the internal pressure filling process of deforming the tire FEM model by applying the internal pressure while maintaining the restrained state, and
A step of returning the elastic constant to the original value and modifying the shape after being deformed by applying the internal pressure to a tire FEM model in which the shape is in a natural state without applying the internal pressure.
A method for generating a tire FEM model, including. The length along the carcass ply from the portion corresponding to the outermost end in the width direction of the reinforcing member in the width direction to the portion corresponding to the tip of the bead filler is set to 100%, and the portion where the tire width is maximized is defined as 100%. The method according to claim 1, wherein the elastic constant of the carcass ply, which is at least 25% outward in the tire radial direction and 25% inward in the tire radial direction as a center, is changed to a value lower than the original value. .. The elastic constant of the carcass ply in the entire region from the portion corresponding to the outermost end in the width direction of the reinforcing member in the width direction to the portion corresponding to the tip of the bead filler is set to a value lower than the original value. The method of claim 1 or 2, which is modified. A tire FEM model in which a tire is represented by a plurality of elements, a carcass ply extending from a tread portion to a bead portion and having an elastic constant set, and a cord arranged outside the carcass ply in the radial direction in the tread portion. A model acquisition unit for acquiring a tire FEM model having a plurality of reinforcing members, a bead filler arranged in the bead portion, and a land portion partitioned by a main groove in the tread portion.
The elastic constant of at least a part of the carcass ply in the region from the portion corresponding to the outermost end in the width direction of the reinforcing member in the width direction to the portion corresponding to the tip of the bead filler is set to be larger than the original value. The elastic constant change part that changes to a lower value,
If there is a land part on the tire equator, set conditions to restrain all the nodes and the bead part that make up the tread of the land part, and if there is a main groove on the tire equator, both sides of the main groove. A constraint condition setting unit that sets conditions for constraining all the nodes and the bead portion that constitute the treads of the two land areas adjacent to the equator.
An internal pressure filling processing unit that executes an internal pressure filling process that deforms the tire FEM model by applying an internal pressure while maintaining the restrained state.
A model modification unit that returns the elastic constant to the original value and modifies the shape after being deformed by applying internal pressure to a tire FEM model that has a natural shape without applying internal pressure.
A tire FEM model generator, including. The elastic constant changing portion has a length of 100% along the carcass ply from the portion corresponding to the outermost end in the width direction of the reinforcing member in the width direction to the portion corresponding to the tip of the bead filler, and the tire. The elastic constant of the carcass ply, which is at least 25% outward in the tire radial direction and 25% inward in the tire radial direction around the portion where the width is maximum, is changed to a value lower than the original value. The device according to claim 4. The elastic constant changing portion is based on the elastic constant of the carcass ply in the entire region from the portion corresponding to the outermost end in the width direction of the reinforcing member in the width direction to the portion corresponding to the tip of the bead filler. The device according to claim 4 or 5, wherein the value is changed to a value lower than the value of. A program that causes a computer to execute the method according to any one of claims 1 to 3.

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