JP6764321B2 - Tire grounding simulation methods, equipment, and programs - Google Patents

Description

The present disclosure relates to tire ground contact simulation methods, devices, and programs.

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; Post Cure Inflation) 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 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 tire ground contact simulation method, an apparatus, and a computer program that appropriately reproduce the influence of PCI processing.

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

The tire contact patch simulation method of the present disclosure is a model to be subjected to ground contact analysis, and includes a step of acquiring a tire FEM model having a main groove and a land portion divided by the main groove in the tread portion, and a state in which the bead portion is restrained. The step of executing the internal pressure filling process of applying the internal pressure to deform the tire FEM model and the shape after being deformed by applying the internal pressure are modified to the tire FEM model having the shape in the natural state without applying the internal pressure. A step and a ground analysis processing step of applying a predetermined internal pressure and a predetermined load to the modified tire FEM model to ground the road surface and calculating the ground contact shape and the force generated on the ground surface under a predetermined boundary condition are included. In the internal pressure filling process, when there is a land part on the tire equatorial line, all the nodes constituting the tread of the land part are restrained to apply internal pressure, and when the tire equatorial line has a main groove, the main groove is applied. Internal pressure is applied by restraining all the nodes that make up the treads of the two land adjacent to each other.

The tire ground contact simulation device of the present disclosure is a model to be grounded analysis, and restrains a model acquisition unit that acquires a tire FEM model having a main groove and a land portion divided by the main groove in the tread portion, and a bead portion. A tire that has an internal pressure filling process that executes an internal pressure filling process that deforms the tire FEM model by applying internal pressure in the state of the tire, and a tire that has a shape after being deformed by applying internal pressure in a natural state without applying internal pressure. Execution of ground contact analysis to calculate the ground contact shape and the force generated on the ground contact surface under the predetermined boundary conditions by applying a predetermined internal pressure and a predetermined load to the model correction part to be modified to the FEM model and the modified tire FEM model to ground the road surface. If there is a land part on the tire equatorial line in the internal pressure filling process, all the nodes constituting the tread of the land part are restrained to apply the internal pressure, and the tire equatorial line has a main groove. In this case, internal pressure is applied by restraining all the nodes constituting the treads of the two land areas adjacent to both sides of the main groove.

In this way, of the treads, the center portion, which 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. This makes it possible to improve the results of grounding analysis. 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.

The block diagram which shows the apparatus which concerns on this disclosure. A flowchart showing a model modification processing routine executed by the device. The figure which shows the model before modification. The figure which shows the model after modification. A comparison diagram showing the shape of the model before modification, the model after modification, and the actual tire. The figure which shows the grounding analysis result. The figure which shows the restraint example of the tread of this disclosure. The figure which shows the restraint example of the tread of this disclosure. The figure which shows the restraint example of the tread of this disclosure.

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

[Tire ground contact simulation device (tire ground contact analysis device)]
The ground contact analysis device 1'has a tire model correction device 1, and applies a predetermined internal pressure and a predetermined load to the modified tire FEM model to ground the road surface, and occurs on the ground contact shape and the ground contact surface under predetermined boundary conditions. Calculate the force (ground pressure, etc.).

[Tire model correction device]
Device 1 modifies the tire model. Specifically, as shown in FIG. 1, the device 1 has a model acquisition unit 10, a processing unit 11, and a model correction unit 12. Each of these parts 10 to 12 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 receives an operation from a user via a known operation unit such as a keyboard or a mouse, and receives data on tire data to be PCI processed and data on PCI processing conditions (internal pressure, restraint position), and these are received. Data is stored in the memory.

The model acquisition unit 10 shown in FIG. 1 generates or acquires a tire FEM model. As shown in FIG. 3, it is an axisymmetric model that is rotationally symmetric around the tire axis and is defined by the tire meridian cross section. The model M0 is formed of tire components such as carcass ply, bead core, bead filler, sidewall rubber and tread rubber, and a finite element model is set for deformation analysis. The tread portion 3 is defined as a main groove 30 and a land portion 31 partitioned by the main groove 30. All the nodes that make up the tread in the land area are set as ground contact 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 in a triangle in the figure mean restraint). ). Further, in the model M0, an internal pressure applying point to which the internal pressure is applied is defined for the inner liner (nodes indicated by arrows in the figure). Physical property values of the members are set for the members constituting the model M0.

When the tire equatorial CL has a land portion 31, the internal pressure filling processing unit 11 shown in FIG. 1 restrains all the nodes constituting the tread surface of the land portion 31 to apply the internal pressure, and mainly applies the internal pressure to the tire equatorial CL. When there is a groove 30, 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. In the example of FIG. 3, there is a main groove 30 in the tire equator CL, and as shown by connecting the nodes to be restrained in the figure in a triangular shape, two main grooves 30 adjacent to the main groove 30 passing through the tire equator CL are shown. All nodes constituting the tread of the groove 30 are restrained. The example of FIG. 3 has a half cross section, but the entire cross section is 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 parts 2 and 3 are restrained. FIG. 7C is an example in which the tire equator CL has a land portion. In this case, the land portion 2 is restrained.

Of course, in the internal pressure filling process, all the tread surfaces of the land portion between the pair of main grooves 30'that are the outermost in the tire width direction may be restrained. In the example of FIG. 7A, land parts 1 and 2 are constrained. In the example of FIG. 7B, the land portions 1, 2, 3 and 4 are restrained. In the example of FIG. 7C, the land parts 1, 2 and 3 are restrained. By doing so, since the deformation of the center portion is suppressed and the shoulder portion and the side portion are deformed, 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 the internal pressure filling processing that deforms the tire FEM model as shown in FIGS. 3 and 4. 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.

As shown in FIG. 4, the model correction unit 12 shown in FIG. 1 corrects the shape after being deformed by applying the internal pressure to the tire FEM model M1 having a shape in a natural state without applying the internal pressure. It can be easily modified by moving the node from the model M0. FIG. 5 shows the actual shape of the 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 obtained by applying an internal pressure corresponding to the PCI treatment to the tire FEM model M0 and deforming 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 can be 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 small at the shoulder portion.

For the tire FEM model M0 and the model M1 modified by 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. Under a predetermined boundary condition, the grounding analysis execution unit 13 applies a predetermined internal pressure to the model to apply a predetermined load to ground the virtual road surface, and calculates the grounding shape and the grounding pressure.

FIG. 6 shows the ground contact shape which is the analysis result. As shown in FIG. 6, the upper part is an actual measurement, the middle part is a comparative example using the model M0, and the lower part is an example using the model M1. The ground contact length ratio (Sh / Ce) of the shoulder portion and the center portion was 1.05 in the actual measurement, 0.774 in the comparative example, and 1.008 in the example. The ground contact width was 118.7 in the actual measurement, 117.0 in the comparative example, and 118.0 in the example. In each case, the examples are closer to the measured values than the comparative examples. Therefore, it can be seen that this method is effective.

[How to fix]
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 having the main groove 30 and the land portion 31 partitioned by the main groove 30 in the tread portion 3.

In the next step ST2, 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 tire equator CL has the land portion 31, and if the tire equator CL has the land portion 31, restrains the tread surface of the land portion 31. (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 processing 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 applying the internal pressure to the model M1 having the shape in the natural state.

As described above, the tire contact patch simulation method of the present embodiment is a model to be grounded analysis, and is 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. The step to acquire (ST1), the step to execute the internal pressure filling process of applying the internal pressure while the bead portion 2 is restrained to deform the tire FEM model M0 (ST6), and the shape after being deformed by applying the internal pressure. The step (ST7) of modifying the tire FEM model M1 to have a shape in a natural state to which no internal pressure is applied, and the modified tire FEM model M1 is grounded on the road surface by applying a predetermined internal pressure and a predetermined load to obtain a predetermined boundary condition. Underneath, it includes a tread analysis processing step to calculate the tread shape and the force generated on the tread surface. In the internal pressure filling process, when the tire equatorial CL has a land portion 31 (ST3: YES), all the nodes constituting the tread of the land portion 31 are restrained to apply the internal pressure (ST4), and the tire equatorial CL is subjected to the internal pressure filling process. When there is a main groove 30 (ST3: NO), internal 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 (ST5).

The tire contact patch simulation device of the present embodiment is a model to be grounded analysis, and is a model acquisition unit that 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. The internal pressure is applied to the internal pressure filling processing unit 11 that executes the internal pressure filling process that deforms the tire FEM model M0 by applying the internal pressure while the bead portion 2 is restrained, and the shape after being deformed by applying the internal pressure. The model modification unit 12 that modifies the tire FEM model M1 that has not been made into a natural shape, and the modified tire FEM model are grounded on the road surface by applying a predetermined internal pressure and a predetermined load, and the ground contact shape is provided under predetermined boundary conditions. And a ground analysis execution unit 13 for calculating the force generated on the ground surface. In the internal pressure filling process, when the tire equatorial CL has a land portion 31, internal pressure is applied by restraining all the nodes constituting the tread of the land portion 31, and when the tire equatorial CL has a main groove 30, the tire equatorial CL has a main groove 30. , All the nodes constituting the treads of the two land portions adjacent to both sides of the main groove 30 are restrained and internal pressure is applied.

In this way, of the treads, the center portion, which 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. This makes it possible to improve the results of grounding analysis. 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.

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

By doing so, since the deformation of the center portion is suppressed and the shoulder portion and the side portion are deformed, it is possible to obtain a tire model that appropriately reproduces the influence of PCI.

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 embodiment described above 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, although the parts 10 to 12 shown in FIG. 1 are realized by executing a predetermined program on the CPU of the computer, each part 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.

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

Claims (5)

A step of acquiring a tire FEM model that is a model to be grounded and has a main groove and a land portion divided by the main groove in the tread portion.
A step of executing an internal pressure filling process that deforms the tire FEM model by applying internal pressure while the bead portion is restrained, and
A step to modify the shape after being deformed by applying internal pressure to a tire FEM model that has a natural shape without applying internal pressure.
Includes a ground contact analysis process step in which the modified tire FEM model is grounded on the road surface by applying a predetermined internal pressure and a predetermined load, and the ground contact shape and the force generated on the ground contact surface are calculated under predetermined boundary conditions.
In the internal pressure filling process, when the tire equator has a land portion, all the nodes constituting the tread of the land portion are restrained to apply the internal pressure, and when the tire equator has a main groove, the main groove is applied. A tire ground contact simulation method in which all the nodes constituting the treads of two land adjacent to both sides of a groove are restrained and internal pressure is applied. The method according to claim 1, wherein in the internal pressure filling process, all the nodes constituting the treads of all the land portions between the pair of main grooves on the outermost side in the tire width direction are restrained. A model acquisition unit that acquires a tire FEM model that is a model to be grounded and has a main groove and a land portion divided by the main groove in the tread portion.
An internal pressure filling process that executes an internal pressure filling process that deforms the tire FEM model by applying internal pressure while the bead portion is restrained.
A model correction part that corrects the shape after being deformed by applying internal pressure to a tire FEM model that has a natural shape without internal pressure applied.
The modified tire FEM model is provided with a ground contact analysis execution unit that applies a predetermined internal pressure and a predetermined load to the road surface and calculates the ground contact shape and the force generated on the ground contact surface under predetermined boundary conditions.
In the internal pressure filling process, when the tire equator has a land portion, all the nodes constituting the tread of the land portion are restrained to apply the internal pressure, and when the tire equator has a main groove, the main groove is applied. A tire ground contact simulation device that restrains all nodes constituting two land treads adjacent to both sides of a groove and applies internal pressure. The device according to claim 3, wherein in the internal pressure filling process, all the tread surfaces of the land portion between the pair of main grooves on the outermost side in the tire width direction are restrained. A program that causes a computer to execute the method according to claim 1 or 2.