JP5211549B2 - Tire model creation method, tire model performance prediction method, and tire design method - Google Patents

Description

  The present invention relates to creation of a tire model used for tire simulation.

  Conventional pneumatic tires have been developed by repeatedly making prototypes with further improvements based on results obtained by subjecting prototypes to running tests and conveyance tests. Such a development method has a problem that development efficiency is low because trial production and testing are repeated. In order to solve this problem, in recent years, there has been proposed a method capable of predicting the physical properties of a tire, that is, the performance of the tire, without producing a prototype by simulation using numerical analysis.

  In the simulation, it is necessary to create a tire analysis model (tire model) created based on the analysis method used for the analysis. Patent Document 1 proposes a method of creating a tire model to be used for analysis by setting a basic model inside based on the outer shape of a tire to be analyzed measured in advance at room temperature.

JP 2002-350294 A

  However, since the technology disclosed in Patent Document 1 sets a basic model every time the outer shape of a tire model is changed, it takes time to create a tire model, and the number of tire models to be evaluated is small. In many cases, it took time to create a tire model.

  The present invention has been made in view of the above, and an object of the present invention is to easily create a tire model having a changed shape and reduce the time required to create many tire models.

  In order to solve the above-described problems and achieve the object, a tire model creation method according to the present invention includes a procedure for creating a reference tire model by dividing a tire into a finite number of elements composed of a plurality of nodes. , A procedure for setting the outer shape of the reference tire model, a procedure for setting a region for changing the shape in the reference tire model, an outer node existing on the outer surface of the reference tire model, and an inner surface of the reference tire model A procedure for obtaining a correspondence relationship with an inner node that exists and defines a thickness of the reference tire model, and aligning the outer node with the outer shape, and between the outer node and the inner node corresponding to the outer node A procedure for moving the inner node while maintaining the relative positional relationship, and the reference tire model other than the moved outer node and the inner node are configured. A step of moving that node, characterized in that it comprises a.

  As a desirable aspect of the present invention, in the tire model creation method, when the outer node is matched with the set outer shape, the outer node between adjacent outer nodes after the outer node is matched with the set outer shape. The ratio of the distance between the outer shape of the reference tire model and the overall length of the outer shape of the reference tire model is a ratio between the distance between the adjacent outer nodes and the overall length of the outer shape of the reference tire model before matching the outer shape. It is preferable that the value is multiplied by the coefficient of.

  As a desirable aspect of the present invention, in the tire model creation method, it is preferable that the region for changing the shape of the reference tire model is composed of at least two regions.

  As a desirable aspect of the present invention, in the tire model creation method, when the inner node is moved while maintaining a relative positional relationship between the outer node and the inner node corresponding to the outer node. The moving inner node is moved in the same manner as the outer node corresponding to the inner node, and the set outer shape is formed by a straight line connecting the outer node after movement and the inner node corresponding to the outer node. The ratio of the two angles is equal to the ratio of the two angles of the outer shape of the reference tire model and the straight line connecting the outer node of the reference tire model and the inner node corresponding to the outer node. Preferably, the inner node is rotated around the outer node corresponding to the inner node.

  As a desirable aspect of the present invention, in the method for creating the tire model, when the nodes of the reference tire model other than the moved outer node and the inner node are moved, in the reference tire model, the outer node; The region surrounded by the inner node corresponding to the outer node is defined as a deformation region, the nodes belonging to the deformation region are extracted, and the relative node position relationship between different nodes belonging to the deformation region is determined, It is preferable to move the nodes belonging to the extracted deformation area while maintaining the node positional relationship.

  In order to solve the above-described problems and achieve the object, the tire model performance prediction method according to the present invention is a procedure for creating a reference tire model by dividing a tire into a finite number of elements composed of a plurality of nodes. A procedure for setting the outer shape of the reference tire model, a procedure for setting a region for changing the shape in the reference tire model, an outer node existing on the outer surface of the reference tire model, and an inner surface of the reference tire model A step of obtaining a correspondence relationship with an inner node that defines the thickness of the reference tire model, and matching the outer node to the outer shape, and the outer node and the inner node corresponding to the outer node; The procedure of moving the inner node while maintaining the relative positional relationship, and the reference tire model other than the moved outer node and the inner node A step of changing a shape of the reference tire model by moving a node to be formed, and a step of executing a simulation for predicting the performance of the tire using the tire model having the changed shape. .

  In order to solve the above-described problems and achieve the object, a tire design method according to the present invention includes a procedure for creating a reference tire model by dividing a tire into a finite number of elements composed of a plurality of nodes, and A procedure for setting the outer shape of the reference tire model, a procedure for setting a region for changing the shape in the reference tire model, an outer node existing on the outer surface of the reference tire model, and an inner surface of the reference tire model And determining the correspondence relationship with the inner node that defines the thickness of the reference tire model, and matching the outer node with the outer shape, and the relative relationship between the outer node and the inner node corresponding to the outer node. A procedure for moving the inner node while maintaining a specific positional relationship, and the nodes constituting the reference tire model other than the moved outer node and the inner node , To change the shape of the reference tire model, to execute a performance simulation using the tire model having the shape changed, and to design a tire based on the result of the performance simulation, It is characterized by including.

  According to the present invention, it is possible to easily create a tire model whose shape has been changed, and to shorten the time required to create many tire models.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the best mode for carrying out the invention (hereinafter referred to as an embodiment). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Although the tire handled in the following embodiment is what is called a pneumatic tire, the application object of this invention is not limited to a pneumatic tire.

  FIG. 1 is a cross-sectional view showing a meridional section passing through a rotation axis of a tire. A carcass 2, a belt 3, a belt cover 4, and a bead core 5 appear on the meridional section of the tire 1. The tire 1 is a composite material structure in which rubber as a base material is reinforced by a reinforcing cord such as a carcass 2, a belt 3, or a belt cover 4 as a reinforcing material.

  The carcass 2 is a strength member that serves as a pressure vessel when the tire 1 is filled with air. The carcass 2 supports a load by its internal pressure and withstands a dynamic load during traveling. The belt 3 is a layer of reinforcing cords in which rubberized cords arranged between the cap tread and the carcass 2 are bundled. In the case of a bias tire, it is called a breaker. In the radial tire, the belt 3 plays an important role as a shape retention and strength member.

  A belt cover 4 is disposed on the grounding surface side of the belt 3. The belt cover 4 is formed by arranging, for example, organic fiber materials in layers, and has a role as a protective layer for the belt 3 and a role as a reinforcing layer for the belt 3. The bead core 5 is a bundle of steel wires that supports the cord tension generated in the carcass 2 by internal pressure. The bead core 5 becomes a strength member of the tire 1 together with the carcass 2, the belt 3, the belt cover 4, and the tread. Next, an apparatus for executing the tire model creation method according to the present embodiment will be described.

  FIG. 2 is a diagram illustrating a configuration example of a tire performance prediction apparatus that predicts tire performance using a tire model created by the tire model creation method according to the present embodiment. FIG. 3 is a diagram illustrating a configuration example of a processing unit of the tire performance prediction apparatus according to the present embodiment. The tire performance prediction device 50 according to the present embodiment executes a tire model creation method according to the present embodiment to create a tire model, and predicts tire performance using the created tire model. .

  As shown in FIG. 2, the tire performance prediction device 50 includes a processing unit 52 and a storage unit 54. An input / output device 51 is connected to the tire performance prediction device 50, and values necessary for creating a tire model by the input means 53 of the input / output device 51, for example, rubber or the like constituting the tire 1 The physical property values (mass density ρ, elastic modulus E) of the fiber material, boundary conditions and travel conditions necessary for prediction of tire performance are input to the processing unit 52 and the storage unit 54.

  Here, an input device such as a keyboard, a mouse, and a microphone can be used for the input means 53. As shown in FIG. 3, the processing unit 52 includes an analysis model creation unit 52 a that creates a tire model 10 to be described later, and an analysis unit 52 b that predicts various performances of the tire using the tire model 10. Yes.

  The storage unit 54 stores a tire performance prediction computer program (hereinafter referred to as “program”) in which the tire performance prediction method according to the present invention is incorporated. Here, the storage unit 54 is configured by a combination of a memory device such as a RAM (Random Access Memory) and a ROM (Read Only Memory), a fixed disk device such as a hard disk, a storage means such as a flexible disk and an optical disk, and the like.

  The above-mentioned program is not necessarily limited to a single configuration, and achieves its function together with a program already stored in a computer system, for example, a separate program represented by an OS (Operating System). There may be. Further, the program for realizing the functions of the processing unit 52 shown in FIG. 3, that is, the functions of the analysis model creation unit 52a and the analysis unit 52b, is recorded on a computer-readable recording medium, and the program recorded on the recording medium The tire model creation method and the tire model creation method according to the present embodiment may be executed by causing the computer system to read and execute. The “computer system” includes hardware such as the OS and peripheral devices.

  The processing unit 52 includes a memory such as a RAM and a ROM, and a CPU (Central Processing Unit). When predicting the performance of a tire, the processing unit 52 reads the program into a memory included in the processing unit 52 and performs calculation based on data for creating a tire model to be described later. The processing unit 52 appropriately stores a numerical value in the middle of the calculation in the storage unit 54 and appropriately calculates the stored numerical value from the storage unit 54 for calculation. The processing unit 52 may realize the analysis model creation unit 52a and the analysis unit 52b with dedicated hardware instead of the program.

  The tire model 10 and tire performance prediction results obtained by the calculation by the processing unit 52 are displayed by the display means 55 of the input / output device 51. The storage unit 54 may be provided in the processing unit 52 or may be provided in another device (for example, a database server). Moreover, the structure which can access the tire performance prediction apparatus 50 from the terminal device provided with the input / output device 51 by either a wired or wireless method may be sufficient. Next, a method for creating a tire model according to the present embodiment will be described.

  FIG. 4 is a flowchart showing a processing procedure of the tire model creation method according to the present embodiment. FIG. 5 is a perspective view showing an example of an analysis model of a tire. 6 is a cross-sectional view showing a meridional section of the tire model shown in FIG. FIG. 7 is a schematic diagram for explaining a method of changing the outer shape of the tire model in the tire model creation method according to the present embodiment. In the tire model creation method according to the present embodiment, first, a tire model (analysis model) 10 used for analysis is created (step S101).

As shown in FIGS. 5 and 6, the analysis model creation unit 52a of the processing unit 52 determines a tire for predicting performance based on a technique used for analysis (a finite element method in the present embodiment) as a finite number of elements 10 ₁ , The tire model 10 is created by dividing into 10 ₂ ... 10 _n . The elements constituting the tire model 10 include, for example, a quadrilateral element in a two-dimensional plane, a solid element such as a tetrahedral solid element, a pentahedral solid element, a hexahedral solid element, etc. It is desirable to use an element that can be used in a computer such as a shell element. The elements divided in this way are identified one by one using the three-dimensional coordinates in the process of analysis.

  In the tire model creation method according to the present embodiment, tire models having different shapes are created based on the tire model 10 created in step S101. Thus, the tire model 10 created in step S101 is a source of a tire model having a different shape, and the tire model 10 is referred to as a reference tire model 10 in the following description.

  After the reference tire model 10 is created, the shape of the reference tire model 10 is changed. For this reason, in this embodiment, the external shape of the reference | standard tire model 10 is changed. Then, the inner shape of the reference tire model 10 is made to follow the changed outer shape while maintaining the relative positional relationship between the outer shape and the inner shape of the reference tire model 10 before the change.

  In order to change the outer shape of the reference tire model 10, the inner surface shape of the molding die used for manufacturing the tire is set (step S102). That is, since the outer shape of the tire is the inner shape of the molding die used for vulcanization of the tire, in this embodiment, the inner shape of the molding die (molding die inner surface shape) is changed and the reference tire model is changed. 10 outer shape is changed. The inner shape of the molding die after the change is, for example, as shown by a solid line LI in FIG.

  Next, an area (shape change area) for changing the shape of the reference tire model 10 is set (step S103). The shape change region of the reference tire model 10 is, for example, a region indicated by A shown in FIG. In the tire model creation method according to the present embodiment, the shape of the reference tire model 10 is changed in the shape change region A by moving the node CP in the shape change region A. Therefore, outside the shape change area A, the shape of the reference tire model 10 is not changed. Here, the shape change area A is arbitrarily set.

  FIGS. 8-1 and FIGS. 8-2 are schematic diagrams illustrating another method for setting a region for changing the shape of the reference tire model. FIGS. In the example shown in FIG. 7, the shape change region of the reference tire model 10 is handled as one region. However, in the tire model creation method according to the present embodiment, the shape change region of the reference tire model 10 set as one region may be divided into a plurality of regions, and the shape change region of the reference tire model 10 may be plural. . That is, the shape change area may be at least two. By doing in this way, the part which wants to maintain a dimension and the part which wants to change a dimension can be reliably reflected by the change of a shape before and after changing the shape of the reference | standard tire model 10. FIG.

  For example, while maintaining the position of the groove from the center of the tire width direction (direction parallel to the tire rotation axis Y axis), the groove width, or the dimensions of the belt 3 (see FIG. 1), the reference tire model 10 When it is desired to change the shape, the shape change area of the reference tire model 10 set as one area is divided into an area including a part where the dimension or the like is to be maintained and an area which does not include a part where the dimension or the like is desired to be maintained. The shape of the tire model 10 is changed. In this way, it is possible to change the shape of the reference tire model 10 while maintaining the dimensions and the like in the region including the portion where the dimensions and the like are to be maintained.

  FIG. 8A shows an example of changing the shape of the reference tire model 10 while maintaining the groove width. In this case, since it is desired to maintain the width of the groove 11 (dimension in the tire width direction), the periphery of the groove 11 is a region (first shape change region) B that maintains the size, and the region that does not include the groove 11 is the second shape change. Set as region C. And in the 1st shape change area | region B, the relative positional relationship (for example, distance between nodes) between nodes CP is maintained, and the shape of the reference | standard tire model 10 is changed.

  FIG. 8-2 shows an example in which the shape of the reference tire model 10 is changed while the length of the belt 3 is maintained. In this case, since it is desired to maintain the length of the belt 3, the portion including the belt 3 is set as a region (first shape change region) B for maintaining the dimensions, and the region not including the belt 3 is set as the second shape change region C. To do. And in the 1st shape change area | region B, the relative positional relationship between the nodes CP is maintained, and the shape of the reference | standard tire model 10 is changed.

  When the shape change region is set in step S103, a node (outer node) CPO located on the outer surface (ie, tread surface) of the reference tire model 10 is extracted (step S104). Then, the outer shape of the reference tire model 10 is changed by matching the extracted outer node CPO with the molding die inner surface shape LI shown in FIG. Next, a correspondence relationship between the outer node CPO extracted in step S104 and the inner node (inner node) CPI for determining the thickness of the reference tire model 10 is obtained (step S105). The inner node CPI thus extracted is moved together with the corresponding outer node CPO. For example, the inner node CPI1 corresponding to the outer node CPO1 moves together with the outer node CPO1 while maintaining the relative positional relationship with the outer node CPO1 (for example, the distance between both nodes).

  The outer node CPO and the inner node CPI are a set of nodes that move the outer node CPO and the inner node CPI together at the tire width direction center CL with reference to the tire width direction center CL shown in FIGS. Associate. Then, a pair of outer nodes CPO and inner nodes CPI, which exist in order from the center CL in the tire width direction of the reference tire model 10 toward the outer side in the width direction, are associated as a set of nodes that are moved together. Further, for example, with reference to a characteristic shape such as the groove 11, the outer node CPO and the inner node CPI constituting such a characteristic shape are associated as a set of nodes to be moved together. In general, the distance between adjacent inner nodes CPI is equal to or less than the distance between adjacent outer nodes CPO. Therefore, using this relationship, a pair of outer nodes CPO and inner nodes CPI that are moved together are associated with each other. May be attached.

  Next, the outer node CPO is moved to match the molding die inner surface shape (solid line LI in FIG. 7) set in step S102 (step S106). In this case, the outer node CPO is matched with the molding die inner surface shape LI by the method described below.

  FIGS. 9A and 9B are schematic diagrams for explaining a method of matching the outer node to the inner shape of the molding die. FIG. 9C is a schematic diagram for explaining the reference length of the outer shape of the tire model. Here, FIG. 9-1 shows the outer node CPO of the reference tire model 10, and FIG. 9-2 shows the outer node CPO of the reference tire model 10 after matching with the molding die inner surface shape LI. Yes.

  In the present embodiment, as shown in the equations (1) and (2), the distance w1 between the adjacent outer nodes CPO of the reference tire model 10 after the outer nodes CPO are matched with the molding die inner surface shape LI or The ratio of w2 to the overall length w after the outer node CPO is matched to the inner surface shape LI of the molding die, the distance L1 or L2 between the outer nodes CPO of the reference tire model 10 and the overall length of the reference tire model 10 The ratio with the length L is multiplied by a predetermined coefficient a1 or a2.

Here, L is the overall length of the outer shape of the reference tire model 10, and the distance of the outer node CPO measured along the outer shape LIB of the reference tire model 10 in the region where the shape of the reference tire model 10 is changed ( The distance between the outer node CPOa and the outer node CPOb). Further, w is the overall length of the outer shape of the reference tire model 10 after the outer node CPO is matched to the inner shape LI of the molding die, and in the region where the shape of the reference tire model 10 is changed, the inner surface of the molding die This is the distance of the outer node CPO measured along the shape LI (the distance between the outer node CPOa and the outer node CPOb).
w1 / w = a1 × (L1 / L) (1)
w2 / w = a2 × (L2 / L) (2)

  Here, the coefficient a1 and the coefficient a2 may be different for each place. By setting the coefficients a1 and a2 to appropriate values for each location, the distance between the reference tire model 10 and the tire model (shape-changed tire model) 10M after the outer node CPO is matched with the molding die inner surface shape LI. Thus, the outer node CPO can be matched to the inner surface shape LI of the molding die while maintaining the size, position, etc. of the portion (for example, groove width, groove position, belt width, etc.) whose dimensions and position are to be maintained.

  For example, by setting the coefficient a1 and the coefficient a2 larger than 1, in the shape-change tire model 10M, the distance between the adjacent outer nodes CPO in the reference tire model 10 is larger than the distances L1 and L2 between the adjacent outer nodes CPO. The distances w1 and w2 can be increased. Further, by setting the coefficient a1 and the coefficient a2 to be smaller than 1, in the shape-change tire model 10M, the distance between adjacent outer nodes CPO in the reference tire model 10 is larger than the distances L1 and L2 between adjacent outer nodes CPO. The distances w1 and w2 can be reduced. Further, if the coefficient a1 is set larger than 1 and the coefficient a2 is set smaller than 1, the distance w1 between the adjacent outer nodes CPO in the shape-change tire model 10M is the distance between the adjacent outer nodes CPO in the reference tire model 10. The distance w2 between the adjacent outer nodes CPO in the shape-changed tire model 10M can be made smaller than the distance L2 between the adjacent outer nodes CPO in the reference tire model 10 that is larger than L1.

  In this way, by adjusting the coefficients a1 and a2, the size and position of the portion where the size and position are desired to be maintained before and after matching the outer node CPO of the reference tire model 10 with the molding die inner surface shape LI. Can do. For example, in the example illustrated in FIG. 8A, in the first shape change region B, the distance between the nodes CP is maintained and the shape of the reference tire model 10 is changed. For this reason, in the first shape change region B, the coefficients a1 and a2 are set to 1. On the other hand, the second shape change area C shown in FIG. 8A changes the distance between the nodes CP in order to adjust the overall dimensions after the shape is changed. For this reason, in the second shape change region B, the coefficients a1 and a2 are set to a value larger than 1 or a value smaller than 1.

  In step S106, when the outer node CPO is matched to the inner surface shape of the molding die, the inner node CPI set in step S105 is maintained in the relative positional relationship between the inner node CPI and the corresponding outer node CPO. Move (step S107). Accordingly, the thickness of the reference tire model 10 can be maintained before and after the inner node CPI is moved. At this time, the ratio of the two angles formed by the line connecting the outer surface of the reference tire model 10 and the inner node CPI and the outer node CPO corresponding to the inner node CPI is determined by the molding die inner surface shape LI and the post-movement The inner node CPI is rotated around the corresponding outer node CPO so as to be equal to the ratio of the two angles formed by the inner node CPI and the line connecting the outer node CPO corresponding to the inner node CPI. Next, this method will be described.

  10A to 10C are schematic diagrams for explaining a method of rotating the inner node around the outer node corresponding to the inner node after moving the outer node. In the tire model used for the analysis, in the meridian section, the mesh is often cut radially outward from the center position in the width direction of the rotation axis of the tire. In this case, the shape of the reference tire model 10 is maintained by maintaining the length of the radiation, that is, the length of the line segment connecting the outer node CPO and the inner node CPI before and after the movement of the outer node CPO and the inner node CPI. Even if it changes, the thickness of the tire model after changing the thickness and shape of the reference | standard tire model 10 can be maintained at the same magnitude | size.

  However, the direction of the radiation that cuts the mesh of the tire model after changing the shape of the reference tire model 10 and the direction of the radiation that cuts the mesh of the reference tire model 10 may be different depending on the shape of the inner surface of the molding die. In such a case, the thickness of the reference tire model 10 cannot be maintained before and after the inner node CPI is moved. Therefore, in the present embodiment, while maintaining the relative positional relationship between the inner node CPI and the outer node CPO corresponding thereto, the outer node CPO and the inner node CPI are moved, and the inner node CPI is moved to the corresponding outer node CPI. Rotate as described above about node CPO.

  FIG. 10A shows the reference tire model 10. Assume that the outer node CPO is B, and the inner node CPI corresponding to the outer node CPO is D. The nodes adjacent to the outer node CPO are denoted as A and C, respectively. At this time, the outer shape LIB configured by connecting A, B, and C represents the outer shape of the reference tire model 10.

  10-2, the outer node CPO (B) of the reference tire model 10 is moved in accordance with the molding die inner surface shape LI, and the inner node CPI (D) corresponding to the outer node CPO (B) is moved. A state in which the relative positional relationship between the two is moved is shown. In FIG. 10-2, the outer node after movement corresponding to the outer node CPO (B) before movement is CPO (B ′), and the inner node after movement corresponding to the inner node CPI (D) after movement is CPI. (D ′). Further, the outer nodes after movement corresponding to the outer nodes A and C before movement are A ′ and C ′, respectively.

  By moving the inner node CPI (D) while maintaining the length of the line segment BD connecting the inner node CPI (D) and the corresponding outer node CPO (B), the inner node CPI (D) The inner node CPI (D) can be moved while maintaining the relative positional relationship with the outer node CPO (B). That is, by making the line segment BD equal to the line segment B′D ′, the relative positional relationship between the inner node CPI (D) and the outer node CPO (B) can be maintained.

  At this time, the angle ratio ∠ABD / ∠CBD between ∠ABD and ∠CBD in the reference tire model 10 is the tire model after the shape is changed, that is, ∠A'B'D 'and ∠C in the shape-changed tire model 10M. The inner node CPI (D ′) after the movement is set so as to be equal to the angle ratio “A′B′D” / ∠C′B′D ′ with “B′D”, and the outer node CPO ( Rotate around B '). As a result, the shape-change tire model 10M is as shown in FIG. As a result, the thickness of the tire model can be maintained at the same size before and after changing the shape while changing the shape of the reference tire model 10. The movement of the inner node CPI toward the corresponding outer node CPO and the rotation of the inner node CPI do not matter in any order. In other words, the inner node CPI may be moved and then rotated, or the inner node CPI may be rotated and then moved. The angle ratio ∠ABD / ∠CBD is preferably equal to the angle ratio ∠A'B'D '/ ∠C'B'D', but in the range of ± 10%, more preferably ± 5%. It only needs to be equal in range.

  When the inner node CPI is moved in step S107, the nodes other than the outer node CPO and the inner node CPI that have been moved (that is, nodes existing inside the reference tire model) are maintained while maintaining the thickness of the reference tire model 10. Move (step S108). Next, this method will be described.

  FIGS. 11A and 11B are explanatory diagrams of a deformation region formed by the outer nodes and the inner nodes of the reference tire model. Here, FIG. 11-2 shows a region surrounded by B in FIG. 11-1. FIGS. 12A to 12C are explanatory diagrams illustrating an example of moving a node existing inside a deformation area including an outer node and an inner node. Up to step S107, the outer node CPO and the inner node CPI of the reference tire model 10 are moved. In step S108, the nodes existing inside the reference tire model 10 are moved. First, in the reference tire model 10, a region surrounded by two adjacent outer nodes CPO and two adjacent inner nodes CPI is defined. This area is called a deformation area.

  In FIG. 11B, two adjacent outer nodes CPO1 and CPO2 and an area surrounded by two adjacent inner nodes CPI1 and CPI2 are a deformation region e1, two adjacent outer nodes CPO2 and CPO3, and an adjacent region. The region surrounded by the two inner nodes CPI2 and CPI3 is the deformation region e2, the two adjacent outer nodes CPO3 and CPO4, and the region surrounded by the two adjacent inner nodes CPI3 and CPI4 is the deformation region e3. . The deformation regions e1 to e3 are set in the reference tire model 10 so as to include the internal nodes to be moved without omission. In the present embodiment, the deformation areas e1 to e3 are quadrangular, but the deformation areas e1 to e3 may be triangular. A method for moving a node existing inside the reference tire model 10 will be described by taking the deformation region e2 as an example.

  As shown in FIG. 12A, the deformation region e2 defined in the reference tire model 10 includes nodes (internal nodes) CPNa and CPNb to be moved. In the present embodiment, the internal node CPNa and the internal node CPNb in the deformation region e2 are other nodes in the reference tire model 10 (for the internal node CPNa, the internal node CPNb, the external nodes CPO2, CPO3, and the internal nodes CPI2, The tire is moved by the tire model after changing the shape while maintaining the relative positional relationship with CPI 3). An example of this method will be described.

  In the present embodiment, the deformation area e2 shown in FIG. 12A and the nodes included in the deformation area e2 (that is, the outer nodes CPO2, CPO3, the inner nodes CPNa, CPNb, and the inner nodes CPI2, CPI3) are normalized. Normalization calculates | requires the positional relationship of all the nodes contained in the deformation | transformation area | region e2, and deform | transforms the deformation | transformation area | region e2 into a square (or rectangle), maintaining the said positional relationship. FIG. 12-2 shows the normalized deformation area e2_P.

  Next, when the outer nodes CPO2 and CPO3 and the inner nodes CPI2 and CPI3 of the reference tire model 10 are moved by the procedure up to step S107, the normalized ones are converted into the deformation region e2_F after the movement. Thereby, the internal nodes CPNa and CPNb of the deformation area e2 can be moved while maintaining the relative positional relationship of the nodes included in the deformation area e2.

  By the procedure up to step S108, a tire model (shape-changed tire model) in which the shape of the reference tire model 10 is changed can be obtained. As can be seen from the procedure described above, the shape-changed tire model can be created without the calculation of the finite element method. If the tire model after a shape change is produced, the process part 52 of the tire performance prediction apparatus 50 shown in FIG. 2 will simulate the tire performance using the produced tire model (step S109). Examples of tire performance simulation include rolling simulation and vibration simulation.

  When the tire performance is simulated, the result is evaluated (step S110), and if necessary, the design is changed (step S111). When it is necessary to change the shape of the tire by changing the design of the tire, the inner shape of the molding die whose shape has been changed is set, and a new shape change is performed using the above-described steps S102 to S108. Create and evaluate a tire model.

  As described above, in the present embodiment, when changing the shape of the reference tire model, the outer shape to be changed, that is, the inner shape of the molding die is set, the outer node existing on the outer surface of the reference tire model, and the inner surface of the reference tire model And the corresponding relationship with the inner node that defines the thickness of the reference tire model. And the tire which changed the shape of the reference tire model by aligning the outer node with the set outer shape and moving the inner node while maintaining the relative positional relationship with the inner node corresponding to the outer node Create a model. Thus, when creating a tire model to be used for analysis, for example, it is possible to easily create a plurality of tire models having different shapes from a tire model having a reference shape without using an analysis method such as a finite element method. it can. As a result, the time required to create many tire models can be shortened.

  As described above, the tire model creation method, tire model performance prediction method, and tire design method according to the present invention are useful for creating a tire model used for numerical simulation, and in particular, many tire models. It is suitable for shortening the time required to create a file.

It is sectional drawing which shows the meridional section which passes along the rotating shaft of a tire. It is a figure which shows the structural example of the tire performance prediction apparatus which estimates the performance of a tire using the tire model created with the creation method of the tire model which concerns on this embodiment. It is a figure which shows the structural example of the process part of the tire performance prediction apparatus which concerns on this embodiment. It is a flowchart which shows the process sequence of the preparation method of the tire model which concerns on this embodiment. It is a perspective view which shows the example which converted the tire into the analysis model. It is sectional drawing which shows the meridian section of the tire model shown in FIG. It is a schematic diagram for demonstrating the method to change the external shape of a tire model in the preparation method of the tire model which concerns on this embodiment. It is a schematic diagram explaining the other method of setting the area | region which changes the shape of a reference | standard tire model. It is a schematic diagram explaining the other method of setting the area | region which changes the shape of a reference | standard tire model. It is a schematic diagram for demonstrating the method to match | combine an outer side node with a shaping die inner surface shape. It is a schematic diagram for demonstrating the method to match | combine an outer side node with a shaping die inner surface shape. It is a mimetic diagram for explaining the standard length of the outside shape of a tire model. It is a schematic diagram for demonstrating the method of rotating an inner node centering on the outer node corresponding to this inner node, after moving an outer node. It is a schematic diagram for demonstrating the method of rotating an inner node centering on the outer node corresponding to this inner node, after moving an outer node. It is a schematic diagram for demonstrating the method of rotating an inner node centering on the outer node corresponding to this inner node, after moving an outer node. It is explanatory drawing of the deformation | transformation area | region comprised by the outer side node and inner side node of a reference | standard tire model. It is explanatory drawing of the deformation | transformation area | region comprised by the outer side node and inner side node of a reference | standard tire model. It is explanatory drawing which shows the example which moves the node which exists inside the deformation | transformation area | region comprised by an outer side node and an inner side node. It is explanatory drawing which shows the example which moves the node which exists inside the deformation | transformation area | region comprised by an outer side node and an inner side node. It is explanatory drawing which shows the example which moves the node which exists inside the deformation | transformation area | region comprised by an outer side node and an inner side node.

Explanation of symbols

1 tire 2 carcass 3 belt 4 belt cover 5 bead core 10 reference tire model (tire model)
10M Shape Change Tire Model 11 Groove 50 Tire Performance Prediction Device 52 Processing Unit

Claims (7)

A procedure for creating a reference tire model by dividing a tire into a finite number of elements composed of a plurality of nodes,
A procedure for setting the outer shape of the reference tire model;
A procedure for setting a region for changing the shape in the reference tire model;
A procedure for obtaining a correspondence relationship between an outer node existing on the outer surface of the reference tire model and an inner node defining the thickness of the reference tire model existing on the inner surface of the reference tire model;
A procedure for moving the inner node while matching the outer node with the outer shape and maintaining a relative positional relationship between the outer node and the inner node corresponding to the outer node;
A procedure for moving the nodes constituting the reference tire model other than the moved outer nodes and the inner nodes;
A method for creating a tire model, comprising: When aligning the outer node with the set outer shape,
The ratio between the distance between the adjacent outer nodes and the overall length of the outer shape of the reference tire model after matching the outer node to the set outer shape before the matching to the outer shape. 2. The method of creating a tire model according to claim 1, wherein a value obtained by multiplying a ratio between a distance between outer nodes and an overall length of an outer shape of the reference tire model by a predetermined coefficient is used. The region for changing the shape of the reference tire model is:
The tire model creating method according to claim 1 or 2, comprising at least two regions. In the case of moving the inner node while maintaining the relative positional relationship between the outer node and the inner node corresponding to the outer node,
Moving the inner node to move in the same manner as the outer node corresponding to the inner node;
The ratio of the two angles formed by the set outer shape and the straight line connecting the outer node after movement and the inner node corresponding to the outer node is
The inner node is set to be equal to a ratio of two angles between the outer shape of the reference tire model and a straight line connecting the outer node of the reference tire model and the inner node corresponding to the outer node. The tire model creating method according to any one of claims 1 to 3, wherein the tire model is rotated around the outer node corresponding to. When moving the nodes of the reference tire model other than the moved outer nodes and the inner nodes,
In the reference tire model, a region surrounded by the outer node and the inner node corresponding to the outer node is defined as a deformation region,
Extracting nodes belonging to the deformation area, and obtaining a relative node position relationship between different nodes belonging to the deformation area,
The tire model creation method according to any one of claims 1 to 4, wherein the nodes belonging to the extracted deformation region are moved while maintaining the node positional relationship. A procedure for creating a reference tire model by dividing a tire into a finite number of elements composed of a plurality of nodes,
A procedure for setting the outer shape of the reference tire model;
A procedure for setting a region for changing the shape in the reference tire model;
A procedure for obtaining a correspondence relationship between an outer node existing on the outer surface of the reference tire model and an inner node defining the thickness of the reference tire model existing on the inner surface of the reference tire model;
A procedure for moving the inner node while matching the outer node with the outer shape and maintaining a relative positional relationship between the outer node and the inner node corresponding to the outer node;
A procedure for changing the shape of the reference tire model by moving the nodes constituting the reference tire model other than the moved outer nodes and the inner nodes; and
A procedure for executing a simulation for predicting the performance of the tire using the tire model whose shape has been changed,
A method for predicting the performance of a tire model, comprising: A procedure for creating a reference tire model by dividing a tire into a finite number of elements composed of a plurality of nodes,
A procedure for setting the outer shape of the reference tire model;
A procedure for setting a region for changing the shape in the reference tire model;
A procedure for obtaining a correspondence relationship between an outer node existing on the outer surface of the reference tire model and an inner node defining the thickness of the reference tire model existing on the inner surface of the reference tire model;
A procedure for moving the inner node while matching the outer node with the outer shape and maintaining a relative positional relationship between the outer node and the inner node corresponding to the outer node;
A procedure for changing the shape of the reference tire model by moving the nodes constituting the reference tire model other than the moved outer nodes and the inner nodes; and
A procedure for performing a performance simulation using the tire model having a changed shape;
Based on the result of the performance simulation, a procedure for designing a tire;
A method for designing a tire, comprising:

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