JP7417062B2 - Tire model creation method and tire model creation device - Google Patents

Description

The present invention relates to a tire model creation method using a computer to create a tire model used for numerical simulation, and a tire model creation device, and particularly to a tire model creation method that creates a tire model that is modeled with high accuracy; The present invention relates to a tire model creation device.

Currently, a method has been proposed in which a computer-analyzable tire model is created and the performance of the tire is numerically simulated. Numerical simulation requires a tire model obtained by dividing the tire into a finite number of elements. In order to obtain a tire model, it is necessary to measure the tire.
For example, Patent Document 1 describes a tire shape measuring device that measures the shape of a tire by providing a grid surface on the surface of the tire and measuring the shape of the grid surface. The tire shape measuring device disclosed in Patent Document 1 includes a rotation means for rotating a tire, a plurality of image input means for inputting images of a lattice surface of the tire rotated by the rotation means from different locations, and a plurality of image input means. a position calculating means for calculating the position of each point on the lattice surface from images of a plurality of lattice surfaces inputted by the means; and a shape of the tire on which the lattice surface is provided based on the position of each point on the lattice surface measured by the position calculation means. and a tire shape regeneration means for regenerating the tire shape.

Patent No. 10-38533

In recent years, there has been a growing demand for reduced air resistance in order to improve the fuel efficiency of automobiles. It has been found that changing tires can significantly worsen a car's aerodynamic drag, increasing the need to investigate the aerodynamic effects of tires using numerical simulations. Therefore, in numerical simulation, it is necessary to precisely model the deformation state of the tire.
Patent Document 1 shows the shape of the side portion of a tire during rolling (see FIG. 6 of Patent Document 1). However, in Patent Document 1, it is not possible to measure the contact area between the tread and the road surface, and it is not possible to precisely model the deformation state of the tire necessary for numerical simulation.

An object of the present invention is to provide a tire model creation method and a tire model creation device that accurately model a tire model for use in computer-based numerical simulation.

In order to achieve the above-mentioned object, a first aspect of the present invention includes a contact step in which a tire is brought into contact with a grounding platform having a plurality of base materials and which can be separated from each other with a predetermined internal pressure and a predetermined load. , a removal process in which the base material other than the area where the tire is in contact with the ground is removed on the ground contact base, a measurement process in which the outer shape of the tire is measured with the tire placed on the ground contact base, and measurement data of the tire outer shape. The present invention provides a method for creating a tire model, comprising the step of creating a simulation tire model that represents a tire and is composed of elements that can be numerically analyzed by a computer.

It is preferable that the area of each of the plurality of base materials constituting the grounding platform is 1 to 400 mm ² .
The height of the ground platform is preferably in the range of 5 mm to the tire diameter.
It is preferable that the simulation tire model is configured with a polygon.
Preferably, the measuring step is a step of measuring the outer shape of the tire using laser light or ultrasonic waves.

A second aspect of the present invention includes a grounding base having a plurality of base materials, the plurality of base materials being separable from each other, and a tire being brought into contact with the grounding base at a predetermined internal pressure and with a predetermined load. a removal unit that removes base material other than the area where the tire is in contact with the ground, a measurement unit that measures the outer shape of the tire with the tire placed on the ground platform, and measurement data of the tire outer shape. The present invention provides a tire model creation device characterized by having a creation section that creates a simulation tire model representing a tire and made up of elements that can be numerically analyzed by a computer.

It is preferable that the area of each of the plurality of base materials constituting the grounding platform is 1 to 400 mm ² .
The height of the ground platform is preferably in the range of 5 mm to the tire diameter.
It is preferable that the simulation tire model created by the creation unit is configured with a polygon.
It is preferable that the measurement unit measures the outer shape of the tire using laser light or ultrasonic waves.

According to the present invention, a tire model used for numerical simulation by a computer can be accurately modeled.

1 is a schematic diagram showing an example of a tire model creation device used in a tire model creation method according to an embodiment of the present invention. (a) is a schematic perspective view showing a first example of a grounding platform, (b) is a schematic perspective view showing a second example of a grounding platform, and (c) is a schematic perspective view showing a third example of a grounding platform. It is a schematic diagram showing an example. (a) is a schematic diagram showing an example of a tire model created by the tire model creation method of the embodiment of the present invention, and (b) is a schematic diagram of the tire model created by the tire model creation method of the embodiment of the present invention. FIG. 7 is a schematic diagram showing another example. (a) is a schematic diagram showing an example of a tire model created by the tire model creation method of the embodiment of the present invention, and (b) is a schematic diagram of the tire model created by the tire model creation method of the embodiment of the present invention. FIG. 7 is a schematic diagram showing another example. (a) to (c) are schematic perspective views showing the tire model creation method according to the embodiment of the present invention in order of steps. (a) is a schematic diagram showing a first example of a conventional tire measuring method, and (b) is a schematic diagram showing a second example of a conventional tire measuring method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The tire model creation method and tire model creation device of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.
Note that the figures described below are illustrative for explaining the present invention, and the present invention is not limited to the figures shown below.

[Tire model creation device]
FIG. 1 is a schematic diagram showing an example of a tire model creation device used in a tire model creation method according to an embodiment of the present invention. FIG. 2(a) is a schematic perspective view showing a first example of a grounding platform, and FIG. 2(b) is a schematic perspective view showing a second example of a grounding platform.
In the tire model creation method of this embodiment, a tire model creation device 10 shown in FIG. 1 is used. The tire model creation method is not limited to the tire model creation device 10 shown in FIG. Further, a program is used that causes a computer to execute each step of the tire model creation method as a procedure. Hereinafter, the tire model creation device 10 will be simply referred to as the creation device 10.

The creation device 10 includes a grounding base 12, a stage 14, a tire support section 16, a removal section 18, a measurement section 20, and a control section 22. Furthermore, it has a creation section 24, a memory 26, an input section 27, and a display section 28. The stage 14 , the tire support section 16 , the removal section 18 , the measurement section 20 , the creation section 24 , the memory 26 , the input section 27 , and the display section 28 are connected to the control section 22 . The control unit 22 manages the operations of the measurement unit 20, creation unit 24, memory 26, and display unit 28, and also controls the operation of the measurement unit 20, creation unit 24, memory 26, and display unit 28 in response to input from the input unit 27. It causes a specific action to be performed.

The grounding stand 12 is a stand on which the tire 30 is placed when being measured. The grounding platform 12 has a plurality of base materials 13 as shown in FIG. 2(a). The plurality of base materials 13 are, for example, quadrangular prisms, and are arranged in contact with each other without any gaps. The plurality of base materials 13 constituting the grounding platform 12 can be separated from each other. The base material 13 is not limited to a square prism, but may be a triangular prism or a hexagonal prism, or a mixture of these may be used.
Note that separable means, for example, that the base materials 13 are simply in contact with each other without using an adhesive or the like. Separable may also mean that the base materials 13 are in contact with each other, for example, by magnets (magnetic force) or by engagement protrusions provided on the base materials 13.
The size of the ground contact area of the tire 30 on the ground platform 12 changes depending on the size of the tire 30, the internal pressure (air pressure) of the tire 30, and the load conditions of the tire 30, so it can be easily separated and easily put together. It is preferable to be able to do so. For this reason, it is preferable that the grounding platform 12 has a form in which the base materials 13 are simply in contact with each other without using an adhesive or the like as described above.

In the grounding platform 12 shown in FIG. 2(a), the surface 13a of the base material 13 has the same size and shape. However, the size of the surface 13a of the base material 13 constituting the grounding platform 12 may be the same or different. The shape of the surface 13a of the base material 13 may be the same or different. For example, the grounding platform 12 may have a configuration in which a plurality of shapes are combined. In this case, the base material 13 may be made smaller in a region corresponding to the outer edge of the ground contact region of the tire 30.
Further, as shown in FIG. 2(b), the surface 13a of the base material 13 may have a combination of a quadrangular shape and a triangular shape, as in the case of the grounding platform 12. In this case, in the area corresponding to the outer edge of the ground contact area of the tire 30, the base material 13 may be made smaller, or the surface may have a triangular shape so that it can be separated more finely.
The surface 12a of the grounding platform 12 is not limited to a flat surface, but may be a curved surface. In this case, as shown in FIG. 2(c), a frame 19a is provided on the ground platform 12 which is curved with a predetermined curvature. Furthermore, a support body 19b is provided on the back surface 12b of the grounding platform 12. In the grounding platform 12, the base material 13 is separable, and by removing the frame 19a after placing the tire 30 with a predetermined load, the base material 13 on which no load is applied is separated. In this way, the base material 13 other than the area where the tire 30 is in contact with the ground can be removed.
Further, the grounding platform 12 may have a surface other than a flat surface or a curved surface depending on the expected road surface condition.

Further, it is preferable that the area of each of the plurality of base materials 13 constituting the grounding platform 12 is 1 to 400 mm ² . The area of each base material 13 is the area of the portion corresponding to the surface 12a of the grounding base 12 that contacts the tire 30, and is the area of the surface 13a of the base material 13.
If the area of each base material 13 is 1 to 400 mm ² , the load when the tire 30 touches the ground 12 can be maintained, the deformation of the ground 12 itself can be suppressed, and it can be easily measured. ,It does not get in the way. Note that when a laser beam is used for measurement, the size is within a range that does not interfere with the laser beam, and a predetermined measurement accuracy can be ensured. This allows the tire model to be modeled with high accuracy.

Further, the height h of the ground platform 12 (see FIGS. 2(a) and 2(b)) is preferably in the range of 5 mm to the tire diameter. Note that the tire diameter is the distance H between the center axis C and the surface 12a of the ground platform 12 in FIG. By setting the height h of the grounding platform 12 in the range of 5 mm to the tire diameter (distance H), a blind spot of the laser beam near the contact edge of the tire with respect to the grounding platform 12 is eliminated, and elastic deformation of the grounding platform 12 is suppressed. Thus, the stability of measurement can be ensured.
The grounding base 12, that is, the base material 13, is preferably made of a material having a higher elastic modulus than tire tread rubber, such as metal, resin, or wood. As described above, by using a material having a higher elastic modulus than the tire tread rubber, deformation of the ground platform 12 can be suppressed even when the tire 30 is brought into contact with the ground under a predetermined load when measuring the tire 30. Thereby, unnecessary deformation of the contact area of the tire 30 with the ground contact base 12 can be suppressed, the reproducibility of measurement can be ensured, and high measurement accuracy can be maintained. Furthermore, since deformation of the grounding platform 12 can be suppressed, the grounding platform 12 can be used repeatedly.

The stage 14 is for determining whether or not the tire 30 is in contact with the ground on the ground platform 12 . It is arranged on the back surface 12b of the grounding stand 12.
For example, a load sensor (not shown) or a pressure sensor (not shown) is arranged on the stage 14. It is preferable that the load or pressure can be detected for each base material 13 that constitutes the grounding platform 12.
The determination of whether or not the tire 30 is in contact with the base material 13 constituting the grounding platform 12 may be determined based on the presence or absence of an output from a load sensor or a pressure sensor, and a threshold value may be set for the load or pressure. The presence or absence of grounding may be determined using a threshold value.
Note that the stage 14 may simply support the ground platform 12 without being provided with a load sensor or a pressure sensor.

The tire support section 16 supports the tire 30 to be measured, and applies a load to the tire 30 to press the outer circumferential surface 30b of the tire 30 against the ground platform 12 with a predetermined load. The tire support section 16 includes a drive section 16a and a shaft section 16b.
The shaft portion 16b supports the tire 30 in a detachable and rotatable manner. The drive section 16a supports the shaft section 16b so as to be movable in a first direction (radial direction of the tire 30) orthogonal to the central axis C of the tire 30, and also moves the shaft section 16b to the tire 30 in the first direction. The structure is such that a load W is applied toward the Note that the mechanism for applying the load W to the tire 30 is not particularly limited, and various conventionally known structures can be used.
While the tire 30 is pressed against the grounding platform 12 with a predetermined load by the tire support section 16, the stage 14 determines whether or not the grounding platform 12 is in contact with the ground, and the stage 14 determines whether or not the tire 30 is in contact with the ground on the grounding platform 12. Remove material 13.

The removal unit 18 removes the base material 13 on the ground platform 12 other than the area where the tire 30 is in contact with the ground. The configuration of the removal unit 18 is not particularly limited, and for example, a configuration in which the stage 14 on the back surface 12b of the grounding platform 12 is partially reduced in size and the base material 13 is dropped can be used.
Further, for example, if the base material 13 of the grounding platform 12 is made to be separated by simply contacting it without an adhesive or the like, the removing section 18 may suck the base material 13 or blow air to remove the base material 13. You can use one that removes. In this case, since the base material 13 that is not in contact with the tire 30 is removed, there is no need to provide a load sensor or a pressure sensor on the stage 14 described above.

The measurement unit 20 measures the outer shape of the tire 30 with the tire 30 placed on the ground platform 12 . At the time of measurement, the tire 30 is in a fixed state. The measurement unit 20 measures the entire circumference of the tire 30, and can obtain measurement data such as three-dimensional data of the outer shape of the tire. The measurement unit 20 preferably measures the tire outer shape using, for example, laser light or ultrasound, and more preferably uses laser light. The measurement unit 20 may measure the entire circumference along the outer peripheral surface 30b of the tire 30, or may be a handy three-dimensional scanner that uses laser light or ultrasonic waves.
Note that an operator may measure the tire 30 using a measuring device such as a caliper to obtain measurement data.
By using the grounding platform 12, the tire 30 is supported in an area corresponding to the grounding surface, so the grounding end 30e (see FIG. 5(b)) of the tire 30 is not covered, and the area that cannot be measured is can be eliminated. Thereby, for example, it is possible to measure even the contact area between the tread of the tire 30 and the road surface. Therefore, high measurement accuracy can be maintained for the simulation tire model 32 (see FIGS. 3(a) and 3(b)).
As mentioned above, in order to investigate the aerodynamic effects of tires, it is necessary to precisely model the deformation state of the tire, but the tire model creation device (tire model creation method) can accurately model the deformation state of the tire. Can be modeled. In this way, the calculation accuracy can be improved by improving the model accuracy, and the measurement accuracy regarding the deformation state of the tire can be improved.

The creation unit 24 uses the measurement data such as three-dimensional data of the outer shape of the tire obtained by the measurement unit 20 to create a simulation tire model that represents the tire and is composed of elements that can be numerically analyzed by a computer. do. In this case, for example, as shown in FIGS. 3A and 3B, a simulation tire model 32 whose shape is obtained up to the ground contact end 32e is obtained. Hereinafter, the simulation tire model 32 will also be simply referred to as the tire model 32.

The configuration of the creation unit 24 is not particularly limited as long as it can create the above-described simulation tire model using measurement data of the tire outer shape. For example, after the measurement is completed, CAD data representing the surface shape of the tire is created based on the measurement data using three-dimensional CAD software or three-dimensional modeling software. As the three-dimensional CAD software, for example, CATIA (registered trademark, Computer graphics Aided Three dimensional Interactive Application) is used, and as the three-dimensional modeling software, for example, Rhinoceros (registered trademark) is used.
Furthermore, mesh generation is performed on the CAD data representing the surface shape of the tire 30 using mesh generation software. As the mesh creation software, for example, HyperMESH (registered trademark) is used.

The simulation tire model (tire external shape model) is preferably configured with a polygon. Therefore, the shape of the mesh is not particularly limited as long as it is a polygon, and may be a triangle or a quadrilateral, or a mixture of triangles and quadrilaterals.
In the tire model for simulation, by expressing the tire external shape as a polygon, it is possible to maintain the approximation accuracy of the tire shape while converting it to a highly versatile format, such as STL (Standard Triangulated Language) format or NASTRAN format. It becomes possible. For example, as shown in FIGS. 4(a) and 4(b), a tire model 32 composed of triangular elements 33 can be obtained. The tire model 32 shown in FIGS. 4(a) and 4(b) is in STL format.

Further, it is preferable that the simulation tire model (tire external shape model) formed of polygons is closed. That is, it is preferable that the simulation tire model (tire external shape model) has no holes on its surface.
The elements that make up the tire model for simulation include, for example, quadrilateral elements on a two-dimensional plane, solid elements such as tetrahedral solid elements, pentahedral solid elements, and hexahedral solid elements, triangular shell elements, and quadrilateral shells on a three-dimensional plane. It may be an element that can be analyzed by a computer, such as a shell element such as an element, or a surface element. In the process of computer analysis, the elements divided in this way are identified one by one using three-dimensional coordinates in a three-dimensional model, and two-dimensional coordinates in a two-dimensional model.

In addition to the above-mentioned simulation tire model, the creation unit 24 may reproduce, for example, a rim, a wheel, and a tire rotation axis on which a tire is mounted as a model in the above-mentioned simulation tire model. good.
If necessary, a model that reproduces the vehicle on which the tires are installed may be incorporated into the above-described simulation tire model. At this time, it is also possible to create a model that integrates a tire model, a rim model (wheel model), and a tire rotating shaft model based on preset boundary conditions.

The memory 26 stores setting conditions such as the load of the tire 30, the air pressure of the tire 30, the threshold value of the load or pressure at the stage 14, and the like.
Further, the memory 26 stores measurement data such as three-dimensional data of the outer shape of the tire, which is obtained by measurement by the measurement unit 20. The creation unit 24 reads measurement data from the memory 26 and creates a tire model for simulation.

The input unit 27 is a variety of input devices for inputting various information to the control unit 22 according to instructions from an operator. The input unit 27 is, for example, a mouse, a keyboard, or the like.
The display unit 28 displays, for example, a simulation tire model representing a tire obtained by a tire model creation method and composed of elements that can be numerically analyzed by a computer, and various known displays may be used. . The display unit 28 also includes a device such as a printer for displaying various information on an output medium.
Further, the control unit 22 can also display various information input via the input unit 27 on the display unit 28.

[Tire model creation method]
FIGS. 5(a) to 5(c) are schematic perspective views showing the tire model creation method according to the embodiment of the present invention in order of steps. As described above, the tire model creation method uses the creation device 10.
First, for example, a grounding platform 12 having a plurality of base materials 13 and separable from each other as shown in FIG. 2(a) is prepared (preparation step). In this case, for example, a plurality of square prism base materials 13 are prepared. Then, the grounding base 12 is prepared by simply bringing a plurality of base materials 13 (quadrangular prisms) into contact with each other without an adhesive or the like. The square prism base materials 13 are in a state that they can be separated from each other.

As shown in FIG. 5(a), the tire 30, which is mounted on a tire rim and whose air pressure has been set to a predetermined internal pressure, is mounted on the surface 12a of the grounding platform 12, which has a plurality of base materials 13 and is separable from each other. Place. Then, a predetermined load W is applied in a first direction perpendicular to the central axis C of the tire 30, and the tire 30 is brought into contact with the surface 12a of the ground platform 12 with a predetermined load (contact step). In the contact step, the tire 30 is attached to the shaft portion 16b using the tire support portion 16 described above, and then the tire 30 is brought into contact with the surface 12a of the grounding base 12 with a predetermined load applied by the drive portion 16a. For example, a tire 30 having a size of 195/65R15 is brought into contact with the ground platform 12 at an internal pressure (air pressure) of 230 kPa and a ground contact load (load load) of 4.5 kN.

Next, as shown in FIG. 5(b), the base material 13 on the grounding base 12 other than the area where the tire 30 is in contact with the ground is removed (removal step). This results in a configuration in which the grounding platform 12 is present only in the area that is in contact with the ground. As described above, the base material 13 of the ground platform 12 can be separated, but the base material 13 cannot be removed due to the pressure exerted by the tire 30 in the area where the tire 30 is in contact with the ground. Utilizing this fact, the base material 13 is physically removed.

Next, with the tire 30 placed on the ground platform 12, the outer shape of the tire is measured to obtain measurement data of the outer shape of the tire (measuring step). In the measurement step, the tire outer shape is preferably measured using, for example, laser light or ultrasonic waves, as described above.
In the example shown in FIGS. 6A and 6B, the tire 100 is grounded on the flat plate 102, but it is difficult to measure the area 103 between the tire 100 and the flat plate 102. Due to the existence of this region 103, it is not possible to measure the contact region between the tread of the tire 100 and the road surface, and the shape accuracy of the tire model decreases. As a result, the accuracy of simulation using a low-accuracy tire model decreases. Therefore, it is necessary to eliminate the region 103 that is difficult to measure.
In the tire model creation method, the above-mentioned area 103 (see FIGS. 6(a) and (b)) is eliminated by making the grounding platform 12 the same size as the area where the tire 30 is in contact with the ground as described above. It is possible to measure even the contact area between the tread of the tire 30 and the road surface. This improves the shape accuracy of the tire model, and as a result, it is possible to perform highly accurate simulation using a highly accurate tire model.

Next, using the measured data of the outer shape of the tire, a simulation tire model that represents the tire and is composed of elements that can be numerically analyzed by a computer is created (creation step). Thereby, for example, a simulation tire model 32 shown in FIG. 5(c) can be obtained.
Note that the method for creating a simulation tire model using measurement data of the tire outer shape is as described above, and therefore a detailed explanation thereof will be omitted.

The creation device 10 creates the above-described simulation tire model by causing the control unit 22 to execute a program (computer software) stored in a ROM or the like. The creation device 10 may be configured by a computer in which each part functions by executing a program as described above, or may be a dedicated device in which each part is configured by a dedicated circuit.

The present invention is basically constructed as described above. Although the tire model creation method, tire model creation device, and program of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various improvements and improvements can be made without departing from the gist of the present invention. Of course, changes may be made.

10 Tire model creation device (creation device)
12 Grounding platform 12a, 13a Front surface 12b Back surface 13 Base material 14 Stage 16 Tire support section 16a Drive section 16b Shaft section 18 Removal section 19a Frame 19b Support body 20 Measurement section 22 Control section 24 Creation section 26 Memory 27 Input section 28 Display section 30 Tire 30b Outer circumferential surface 32 Simulation tire model (tire model)
32e Ground contact end 33 Element 100 Tire 102 Flat plate 103 Area C Central axis H Distance h Height

Claims (8)

a contacting step of bringing the tire into contact with a grounding base having a plurality of base materials that can be separated from each other with a predetermined internal pressure and with a predetermined load;
a removing step of removing the base material in the area other than the area where the tire is in contact with the ground on the grounding base;
a measuring step of measuring the outer shape of the tire with the tire placed on the ground platform;
A method for creating a tire model, comprising the step of creating a simulation tire model that represents the tire and is composed of elements that can be numerically analyzed by a computer, using the measured data of the outer shape of the tire. The tire model creation method according to claim 1, wherein the area of each of the plurality of base materials constituting the grounding platform is 1 to 400 mm ² . The tire model creation method according to claim 1 or 2 , wherein the simulation tire model is formed of a polygon. The tire model creation method according to any one of claims 1 to 3 , wherein the measuring step is a step of measuring the outer shape of the tire using laser light or ultrasonic waves. a grounding platform having a plurality of base materials and separable from each other;
a removal unit that removes the base material other than the area where the tire is in contact with the ground on the grounding platform while the tire is in contact with the grounding platform at a predetermined internal pressure and with a predetermined load;
a measurement unit that measures the outer shape of the tire with the tire placed on the ground platform;
A tire model creation device comprising: a creation unit that creates a simulation tire model that represents a tire and is made up of elements that can be numerically analyzed by a computer, using the measurement data of the tire outer shape. The tire model creation device according to claim 5 , wherein the area of each of the plurality of base materials constituting the grounding platform is 1 to 400 mm ² . The tire model creation device according to claim 5 or 6 , wherein the simulation tire model created by the creation section is configured of a polygon. The tire model creation device according to any one of claims 5 to 7 , wherein the measuring section measures the outer shape of the tire using laser light or ultrasonic waves.