JP4496716B2 - Tire simulation method, tire performance prediction method, tire manufacturing method, tire and program - Google Patents

Description

【００６０】
以上のようなタイヤ性能の予測方法は、例えば、タイヤモデル２０１を構成するトレッドパターンを備えていないタイヤ基台モデルおよびトレッドパターンモデルを予め種々用意しておき、この用意されたモデルの中から、タイヤ性能の予測結果が最も良好なタイヤ基台モデルおよびトレッドパターンモデルの組み合わせを効率よく選択する際に有効に用いることができる。また、遺伝的アルゴリズムなどの最適化手法を用いてタイヤ基台モデルおよびトレッドやパターンモデルを逐次修正しながら、最適なタイヤモデルを効率よく求める際に有効に用いることができる。こうして選択された、あるいは見出されたタイヤモデルを実現するタイヤを設計し、このタイヤを製造するタイヤ製造用金型を設計し、このタイヤ製造用金型を用いて設計したタイヤを製造することができる。
本発明はこのようなタイヤ製造方法およびこの製造方法を用いて製造されたタイヤを提供する。
【００６１】
なお、上記実施形態では、タイヤモデルが直進する場合を説明したが、本発明では、路面モデル上を移動するタイヤモデルが旋回運動するものであってもよい。この場合、流体解析領域は、タイヤモデルの旋回する方向に追従して路面モデル上は２次元的に移動するとよい。さらに、本発明では、タイヤモデルの走行速度が加速度を持って加速、減速するものであってもよい。
また、上記実施形態では、タイヤが路面に設けられた水膜上を通過するタイヤのシミュレーション方法およびタイヤ性能予測方法を中心に説明したが、本発明における流体物質は水膜を構成する水に限らず、液体または気体であってもよい。例えば、移動するタイヤ周りの空気の流れをシミュレーションしてタイヤ性能を予測するものであってもよい。
【００６２】
以上、本発明のタイヤのシミュレーション方法、タイヤ性能予測方法、タイヤ製造方法、タイヤおよびプログラムについて詳細に説明したが、本発明は上記実施例に限定はされず、本発明の要旨を逸脱しない範囲において、各種の改良および変更を行ってもよいのはもちろんである。
【００６３】
【発明の効果】
以上、詳細に説明したように、本発明は、タイヤモデルを用いて路面を移動するタイヤの挙動を再現する際、路面モデル上の一部の空間領域をメッシュ分割した複数の領域要素を有し、この空間領域に流体物質を充填した流体解析領域を、タイヤモデルの移動に応じて移動させるので、流体解析領域の長さを短くして領域要素数を減少させることができ、流体物質とタイヤモデルの干渉を計算する動的解析の計算処理時間を短縮することができる。これにより、実用的なタイヤ性能の予測を可能にする。
【図面の簡単な説明】
【図１】 本発明のタイヤのシミュレーション方法およびタイヤ性能予測方法を行うタイヤ性能予測装置の概略の構成を示した概略構成図である。
【図２】 本発明のタイヤのシミュレーション方法およびタイヤ性能予測方法で作成される各種モデルの一例を示す斜視図である。
【図３】 （ａ）〜（ｃ）は、本発明のタイヤのシミュレーション方法およびタイヤ性能予測方法で用いられる流体物質の配置を説明する図である。
【図４】 本発明のタイヤのシミュレーションおよびタイヤ性能予測方法の流れの一例を示すフローチャートである。
【図５】 本発明のタイヤのシミュレーションおよびタイヤ性能予測方法において行われる動的解析の処理の流れを示すフローチャートである。
【図６】 本発明のタイヤのシミュレーションおよびタイヤ性能予測方法において行われる、タイヤモデルが流体解析領域に進入する直前の状態を示す図である。
【図７】 タイヤモデルが流体解析領域に進入して、流体物質を部分的に排除した状態を模式的に説明する図である。
【図８】 タイヤモデルと流体物質との境界面の計算の流れを示すフローチャートである。
【図９】 （ａ），（ｂ）は境界面の計算を説明する説明図である。
【図１０】 （ａ）および（ｂ）は、本発明のタイヤのシミュレーションおよびタイヤ性能予測方法において行われるマッピング処理を模式的に説明する説明図である。
【図１１】 （ａ）〜（ｃ）は、本発明のタイヤのシミュレーションおよびタイヤ性能予測方法で設定された流体解析領域にタイヤモデルが進入する状態を模式的に表す図である。
【図１２】 （ａ）〜（ｃ）は、従来のタイヤ性能予測方法で設定された流体解析領域にタイヤモデルが進入する状態を模式的に表す図である。
【図１３】 本発明のタイヤ性能予測方法で抽出された物理量の一例を表す図である。
【図１４】 従来のタイヤ性能予測方法で作成されるタイヤモデルおよび流体モデルの一例を示す斜視図である。
【符号の説明】
１００ タイヤ性能予測装置
１１０ ＣＰＵ
１２０ メモリ
２００ モデル作成部
２０１ タイヤモデル
２０２ 路面モデル
２０３ 流体解析領域
３００ 静的解析部
４００ 転動処理部
５００ 動的解析部
６００ 物理量抽出部
７００ タイヤ性能予測部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire simulation method, a tire performance prediction method, a tire manufacturing method, a tire and a program that reproduce the behavior of a tire traveling on a road surface, and particularly when the tire passes over a water film formed on a road surface. The present invention relates to a tire simulation method that reproduces tire behavior and a tire wet performance prediction method.
[0002]
[Prior art]
A method of predicting wet performance on a wet road surface of a pneumatic tire (hereinafter simply referred to as a tire) mounted on a vehicle by using a finite element method or a finite volume method in accordance with improvement in computer processing capacity in recent years. Various proposals have been made.
The wet performance of a tire means that, for example, when a tire runs on a water film accumulated on the road surface, water enters between the tire and the road surface, and the grip force to the road surface that the tire has decreases. As represented by the hydroplaning phenomenon in which a tire slides on a water film and control of the tire is not effective, the tire performance is reduced due to water intervening between the tire and the road surface.
Such a decrease in tire performance is likely to occur when the running speed (translation speed) of the tire increases. Therefore, when the wet performance is predicted using the finite element method or the finite volume method, the translation speed is high. It is necessary to perform a calculation process using a finite element model of the tire. In the case of hydroplaning performance, for example, a finite element model of a tire that reproduces a dynamic state of a translation speed of 80 to 100 km / hour must be created.
[0003]
Therefore, when evaluating hydroplaning performance using a finite element model of a tire, rolling of the finite element model of a stationary tire is started on a water film model that reproduces a water film until the predetermined translation speed is reached. The translation speed must be increased. Alternatively, a finite element model of a tire that has reached a predetermined traveling speed in advance must be rolled until it reaches a steady state on a water film model created on a road surface model. In any case, it is necessary to evaluate the hydroplaning performance by securing the length of the water film model along the traveling direction of the finite element model of the tire.
[0004]
In Patent Document 1 below, tire performance prediction is performed to predict tire performance by calculating a physical quantity generated when a tire model comes into contact with a fluid model using a tire model of a finite element model and a fluid model of a finite volume model. Proposed method. In the said patent document 1, the area | region which forms the fluid model which is a water film model is created as a thing containing the area | region where a tire model moves (refer the said patent document 1 [0061]). Then, when the tire model enters the fluid model, each microfluidic element that divides the fluid region of the fluid model is sequentially examined for all the microfluidic elements to determine whether or not there is an interference portion with the tire model. The boundary condition that the model gives to the tire model and the boundary condition that the tire model gives to the fluid model are set. By calculating the deformation of the tire and the flow of the fluid model based on these boundary conditions, the behavior of the tire model when passing through the fluid model can be calculated. It is described that the performance can be predicted.
[0005]
[Patent Document 1]
Japanese Patent No. 313338
[0006]
[Problems to be solved by the invention]
However, in the tire performance prediction method described in Patent Document 1, as shown in FIG. 14, a fluid model is created in an extremely long region in which the tire model moves, and for each microfluidic element of the fluid model, It is necessary to sequentially check whether there is any interference part. For this reason, the calculation process for predicting the tire performance takes an extremely long time, for example, several tens of hours to several hundreds of hours, which is not practical in terms of calculation processing speed.
These computational speed problems can be solved by improving the processing power of computers. However, in order to accurately predict tire performance by the emergence of computers with improved processing power, tire models and microfluidics It is necessary to use a high-definition model in which elements are further subdivided, and it is clear that a similar problem occurs in this case.
[0007]
In Patent Document 1, in order to solve the problem of calculation processing efficiency, the movement trajectory and deformation history of the belt portion of the smooth tire model when the smooth tire model without a tread pattern is rolled are obtained in advance ( Global analysis) By applying this trajectory as a forced input to the belt part of a tire model with a tread pattern in part, a global / local analysis that analyzes the effect of the tread pattern of the tire model on the fluid model (local analysis) Has proposed. However, in this analysis method, when executing the local analysis, it is necessary to forcibly input the deformation history of the belt portion in accordance with a result calculated in advance by a smooth tire model or the like. For this reason, the deformation of the belt portion of the tire model with a tread pattern is restrained at the time of local analysis, and therefore there is a problem that it is impossible to obtain an analysis result considering the difference in deformation of the belt portion due to the difference in the tread pattern. .
[0008]
Accordingly, the present invention proposes a tire simulation method and a tire performance prediction method for efficiently and quickly predicting tire performance including tire wet performance in order to solve the above problems. Another object of the present invention is to provide a computer program for executing a tire manufacturing method, a tire, and a tire simulation method using the tire performance prediction method.
[0009]
[Means for Solving the Problems]
To achieve the above object, the present invention is a tire simulation method for reproducing the behavior of a tire traveling on a road surface, a road surface model reproducing the road surface, a tire model moving on the road model, A model creation step for creating a fluid analysis region having a plurality of region elements obtained by meshing a partial space region on the road surface model and filling the space region with a predetermined fluid substance; When the tire model enters the fluid analysis region, a boundary condition that the tire model gives to the fluid material in the fluid analysis region is set, and the flow of the fluid material in the fluid analysis region is determined based on the boundary condition. A fluid calculation step for calculating, an analysis region moving step for moving the fluid analysis region in accordance with the movement of the tire model, and the tire model A deformation calculation step of setting a boundary condition given to the tire model by the flow of the fluid substance in the fluid analysis area by entering the fluid analysis area, and calculating a deformation of the tire model based on the boundary condition; There is provided a tire simulation method comprising: a fluid calculation step, an analysis region movement step, and a repetition step of repeatedly performing the deformation calculation step.
[0010]
In the repetition step, the boundary condition in the next deformation calculation step is given based on the physical quantity of the fluid substance obtained in the fluid calculation step, and the deformation of the tire model obtained in the deformation calculation step is performed. Based on this, it is preferable that the boundary condition in the next fluid calculation step is given.
Further, in the analysis area moving step, the physical quantity of the fluid substance in each area element of the fluid analysis area after movement is generated by mapping the physical quantity of the fluid substance in each area element of the fluid analysis area before movement. Preferably it is done. At this time, the mapping process is performed, for example, by using, as a weighting factor, an element variable having an overlapping portion where the region element of the fluid analysis region after movement overlaps with the region element of the fluid analysis region before movement, in the fluid analysis region before movement. This is a process of weighted average of physical quantities in each area element. The element variable is, for example, the ratio of the element volume of the overlapping portion to the area element of the fluid analysis region after movement that overlaps the area element of the fluid analysis area before movement. In addition to the ratio of the element volume, for example, the ratio of the surface area of the overlapping part, the ratio of the mass of the fluid substance in the overlapping part, the ratio of the flow rate of the fluid substance, and the like can be mentioned.
Preferably, the physical quantity of the fluid substance includes at least one of a fluid pressure of the fluid substance, a flow rate of the fluid substance, and a volume content of the fluid substance included in the region element.
[0011]
In the fluid calculation step, it is preferable to calculate the flow of the fluid material by applying gravitational acceleration to the fluid material.
Further, in the analysis region moving step, in addition to the boundary condition given to the fluid material by the tire model, the fluid material flows into the front end surface in the moving direction of the tire model among the boundary surfaces of the fluid analysis region. A boundary condition that allows only the outflow of the fluid substance to the rear end surface of the fluid analysis region, and in the fluid calculation step, of the region analysis element, A restraint condition for restricting the flow of the fluid material is applied to at least a region element at the front end that is located at the front end and the front end surface is in contact with the fluid material so that the fluid material has a flow velocity in the moving direction of the tire model. Is preferred. At this time, it is preferable that a boundary condition for prohibiting outflow and inflow of the fluid substance is given to the side surface and the lower surface of the fluid analysis region among the boundary surfaces of the fluid analysis region.
[0012]
Further, the length of the fluid analysis region in the movement direction of the tire model is the maximum contact length in the movement direction of the tire model when the tire model is in contact with a portion of the road surface model without the fluid analysis region. It is preferably 0.5 times or more and 4 times or less.
The tire model is preferably a finite element model created by dividing a tire constituent member into a finite number of elements.
[0013]
The present invention further includes a step of calculating at least one of a physical quantity acting on the tire model and a physical quantity of the fluid substance by performing the tire simulation method, and a step of predicting tire performance based on the calculated physical quantity. And providing a tire performance prediction method characterized by comprising:
[0014]
Furthermore, the present invention provides a tire manufacturing method characterized by manufacturing a tire designed using the tire performance prediction method. Furthermore, the present invention provides a tire manufactured using this tire manufacturing method.
[0015]
Furthermore, the present invention is a computer-executable program for causing a computer to execute a tire simulation method that reproduces the behavior of a tire traveling on a road surface, the road surface model reproducing the road surface, and the road surface model. A moving tire model, and a fluid analysis region having a plurality of region elements created by meshing a partial space region on the road surface model and filling the space region with a predetermined fluid substance, A model creation procedure to be created by a computing means of a computer, and a boundary condition given to the fluid substance in the fluid analysis region by the tire model when the tire model enters the fluid analysis region. A fluid calculation procedure for causing the calculation means to calculate the flow of the fluid substance in the fluid analysis region, and the tire model. An analysis region moving procedure for causing the arithmetic means to move the fluid analysis region in accordance with the movement of the fluid, and the flow of the fluid substance in the fluid analysis region is caused by the tire model entering the fluid analysis region. A deformation calculation procedure for setting a boundary condition to be given to the tire model, and causing the calculation means to calculate a deformation of the tire model based on the boundary condition, the fluid calculation procedure, the analysis region moving procedure, and the Provided is a program characterized by repeatedly performing a deformation calculation procedure.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a tire simulation method, a tire performance prediction method, a tire manufacturing method, a tire and a program according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
[0017]
FIG. 1 is a schematic configuration diagram showing a schematic configuration of a tire performance prediction apparatus (hereinafter referred to as the present apparatus) 100 for performing a tire simulation method and a tire performance prediction method of the present invention in a block diagram.
[0018]
The apparatus 100 includes a model creation unit 200 that creates various models including a tire model to be analyzed or a tire model attached to a rim model, and static analysis processing, for example, a tire model to which a rim model is attached. A static analysis unit 300 that performs an internal pressure filling process and performs a grounding process that deforms the ground by applying a vertical load, and a stationary tire model that has been subjected to the grounding process by the static analysis unit 300 at a predetermined traveling speed. It acts on a rolling processing unit 400 that rolls, a dynamic analysis unit 500 that performs analysis (dynamic analysis) of a dynamic state on a wet road surface such as a hydroplaning state, and a tire model that performs the dynamic analysis. A physical quantity extraction unit 600 that extracts a physical quantity; and a tire performance prediction unit 700 that predicts tire performance on a wet road surface based on a physical quantity extraction result. . Furthermore, it has CPU110 which performs the function and control of each said part, and the memory 120 which memorize | stores and hold | maintains the result produced in each part.
[0019]
The device 100 may be a device configured by a computer in which each part exerts a function by executing a program, may be a dedicated device configured by a dedicated circuit, or a part thereof by a computer. The other part may be configured by a dedicated circuit.
[0020]
FIG. 2 is a perspective view showing an example of various models created by the model creation unit 200.
The model creation unit 200 creates a tire model 201 with a tread pattern based on model creation conditions set by the operator using an operation system such as a mouse or a keyboard (not shown). Further, the separately created rim model is merged with the tire model 201 to create the tire model 201 with the rim model attached thereto. In FIG. 2, the rim model is omitted. Further, a road surface model 202 that is a rigid plane model and a fluid analysis region 203 are created on the road surface model 202.
[0021]
The fluid analysis region 203 shown in FIG. 2 has a plurality of region elements created by dividing a part of the spatial region on the road surface model 202 into meshes, and the density and viscosity of water or the like in the fluid analysis region 204. This is a region where a so-called fluid model is formed in which fluid substances characterized by coefficients are arranged.
[0022]
Here, although the fluid substance exists in the fluid analysis region 203, the fluid substance can be initially set and arranged as shown in FIGS.
For example, as shown in FIG. 3A, the fluid substance is arranged with a uniform thickness (depth) on the entire lower surface region in contact with the road surface model 202 of the fluid analysis region 203. As shown in FIG. 3 (b), the fluid material has a uniform thickness in a part of the front of the tire model 201 in the moving direction so that the tire model 201 contacts the fluid material after entering the fluid analysis region 203 to some extent. It is arranged at a depth (depth). Further, as shown in FIG. 3C, in the region filled with the fluid substance shown in FIG. 3B, the width direction wider than the tire width of the tire model 201 (the direction orthogonal to the moving direction of the tire model 201). ) Is disposed with a uniform thickness (depth).
[0023]
Further, gravitational acceleration is applied to the fluid substance. For example, when it is possible to analyze a phenomenon in which a fluid such as water splashed forward in the tire moving direction by the tire is scattered in the space and landed on the road surface again, the action of gravity acceleration is required. Because. By causing the gravitational acceleration to act on the fluid substance, it is possible to more accurately reproduce the actual fluid flow, and it is possible to accurately reproduce the rebound of water generated near the front end of the contact surface of the tire.
[0024]
Of the boundary surface of the fluid analysis region 203, when the fluid analysis region 203 is moved together with the tire model 201 to the front end surface in the moving direction of the tire model 201, the fluid material is always allowed to flow only from the front end surface. Boundary conditions are assigned so that Further, the rear end face located on the opposite side of the moving direction of the tire model 201 among the boundary faces of the fluid analysis area 203 is such that only the outflow of the fluid substance is allowed when the fluid analysis area 203 is moved. Conditions are granted.
[0025]
In order to perform a simulation in which the tire model 201 moving on the road surface model 202 steps on the fluid substance over a long moving distance, the boundary condition is set so that the fluid substance flows in from the front end face of the fluid analysis region 203 and is replenished with the fluid substance. Is granted. When the fluid substance is not replenished from the front end face, the fluid substance moves in the direction opposite to the movement direction of the tire model 201 (backward) with the movement of the fluid analysis region 203, This is because the fluid substance that was in front no longer exists.
[0026]
Further, when gravitational acceleration is applied to the fluid substance, the fluid analysis area 203 has a side surface and a lower face so that the fluid substance existing at a certain thickness in the fluid analysis area 203 does not flow out of the fluid analysis area 203 due to its own weight. Is provided with boundary conditions for prohibiting the inflow and outflow of fluid substances. Inflow and outflow of the fluid substance are not prohibited on the upper surface of the fluid analysis region 203. If no boundary condition is given to the side surface of the fluid analysis region 203, the fluid substance flows out from the side surface, and a certain thickness (depth) cannot be maintained.
[0027]
Here, the length of the fluid analysis region 203 in the moving direction when the tire model 201 rolls and moves the road surface model 202 as described later is the same as the road surface model 202 when the tire model 201 contacts the road surface model 202. It is preferable that the contact length is 0.5 to 4 times the maximum contact length in the moving direction. If the fluid analysis area 203 is smaller than 0.5 times, the drainage property that the tire moves while removing water on the road surface cannot be reproduced. If the fluid analysis area 203 is larger than 4 times, the scale of the fluid analysis area 203 becomes large. This is because the reduction in processing time required for analysis is reduced. Since the fluid analysis region 203 has the length in this range, the behavior of the tire when the moving tire passes through the water film can be accurately reproduced while reducing the processing time required for the calculation.
[0028]
The tire model 201 is a three-dimensional finite element model configured by dividing a tire constituent member into a finite number of deformable elastic elements. For example, components such as a carcass reinforcing member, a belt reinforcing member, and a bead reinforcing member are shell elements having tension and bending rigidity, and rubber members such as tread rubber members, sidewall rubber members, bead filler rubber members, carcass coats, and the like. Components such as rubber members are made of tetrahedron, pentahedron, hexahedron solid element, and the like.
[0029]
The static analysis unit 300 performs a static analysis process, for example, an internal pressure filling process for filling a predetermined internal pressure on the tire model 201 to which the rim model created by the model creation unit 200 is mounted, and is grounded to the road surface model 202. And a grounding process for grounding and deforming the tire model 201.
[0030]
The rolling processing unit 400 puts the tire model 201 in a rolling state so that the tire model 201 subjected to the ground contact process is moved at a predetermined traveling speed. Here, the tire model 201 is processed so as to move from a stationary state at a predetermined traveling speed, but this processing method is not particularly limited. For example, a method of giving a predetermined rotation speed and translation speed (travel speed) around the tire rotation axis to the tire model 201, and gradually increasing the rotation speed and translation speed to achieve the target rotation speed and travel speed. The tire model 201 in a desired rolling state is used. Alternatively, the tire model 201 and the mounted rim model (not shown) are once converted into a rigid body model that does not allow deformation, and thereafter the target rotational speed and translation speed (traveling speed) are instantaneously input, and then the rigid body model. A tire model 201 in a desired rolling state may be created using a method for restoring the tire model to a deformable tire model and a rim model. This method is described in detail in Japanese Patent Application No. 2002-332168 filed by the present applicant.
[0031]
The dynamic analysis unit 500 is set with a boundary condition setting unit that sets a boundary condition between the tire model 201 in the dynamic state created by the rolling processing unit 400 and the road surface model 202 in which the fluid analysis region 203 is formed. A tire / fluid calculation unit for performing deformation calculation of the tire model 201 in a rolling state (dynamic state) and flow calculation of fluid material in the fluid analysis region 203 based on the boundary condition , And is configured.
In the tire / road surface model calculation unit, when the calculation result of the fluid substance in the fluid analysis region 203 or the calculation result of the tire model 201 does not satisfy the predetermined condition, the tire / road surface model calculation unit returns to the boundary condition setting unit, The above calculation is repeated by setting the flow of the fluid substance as a new boundary condition.
In the calculation, a cornering state in which the tire model 201 has a camber angle or a slip angle, or a braking state in which braking torque or driving torque is applied to the tire rotation shaft may be calculated.
In addition, when the tire model 201 enters the fluid analysis region 202 for a predetermined length and the boundary condition that the tire model 201 gives to the fluid substance in the fluid analysis region 202 is set, the fluid analysis region 202 It is configured to move in the tire moving direction in accordance with the movement.
[0032]
The physical quantity extraction unit 600 is a part that calculates a physical quantity of the created tire model 201 in a dynamic state.
For example, when the tire model 201 enters the fluid analysis region 203 on the road surface model 202, the buoyancy that the fluid substance in the fluid analysis region 203 acts on the tire model 201 is analyzed. Receiving tread reaction force, volume content of fluid substance contained in each area element in fluid analysis area 203, fluid pressure of fluid substance, flow velocity, flow rate, energy density, or various distributions of energy, and road surface of tire model 201 A contact shape, a contact area, a contact pressure distribution, etc. in contact with the model 202 are calculated as physical quantities.
The tire performance prediction unit 700 is a part that predicts the quality of the wet performance based on the calculated physical quantity.
[0033]
When the present apparatus 100 is configured by a computer, the following programs are executed so that each part functions. That is, a road surface model 202 that reproduces a road surface, a tire model 201 that moves on the road surface model 202, and a plurality of area elements that are created by dividing a partial spatial area on the road surface model 202, A model creation procedure for causing the CPU 110 to create a fluid analysis region 203 filled with a predetermined fluid substance in the space region, and the tire model 201 in the fluid analysis region 203 when the tire model 201 enters the fluid analysis region 203. A boundary condition to be given to the fluid substance is set, a fluid calculation procedure for causing the CPU 110 to calculate the flow of the fluid substance in the fluid analysis region 203 based on the boundary condition, and storing the calculation result in the memory 120, and movement of the tire model 201 In response, the analysis region moving procedure for causing the CPU 110 to move the fluid analysis region 203 and the tire model The boundary condition that the fluid substance in the fluid analysis region 203 gives to the tire model 201 when the robot 201 enters the fluid analysis region 203 is set, and the CPU 110 calculates the deformation of the tire model 201 based on the boundary condition. A deformation calculation procedure for storing the result in the memory 120, and the calculation result of the fluid substance in the tire model 201 or the fluid analysis region 203 includes the fluid calculation procedure, the analysis region movement procedure, and the deformation calculation procedure. Repeat until a predetermined condition is met.
[0034]
Such an apparatus 100 can create a tire model in a dynamic state along the flow shown in FIG. 4 and predict wet performance.
FIG. 4 is a flowchart showing an example of the flow of the tire simulation and tire performance prediction method of the present invention.
First, model creation conditions and rolling conditions are input to the apparatus 100 by an operating system (not shown) from an operator.
The model creation conditions include how to configure the tire model 201 with the tread pattern, the road surface model 202, and the fluid analysis region 203, the shape of the model, the number of mesh divisions, or the arrangement of finite elements in the case of a finite element model. Or a finite element stiffness parameter or the like.
On the other hand, the rolling condition is a translation speed (traveling speed), a rotational speed, a load applied to the tire model 201, and a road surface model 202, which determine a dynamic state of the tire model 201 to which a rim model (not shown) is attached. This is a condition relating to the movement and grounding of the tire model 201 such as the friction coefficient.
[0035]
First, the model creation unit 200 creates a tire model 201 with a tread pattern (step S201).
The tire model 201 is created, for example, by creating a tire base model that models a tire casing portion without a tread pattern portion of a tire and a tread pattern model that reproduces the tread pattern portion, and this tread pattern model is used as a tire base model. The tire model 201 is created by merging. Alternatively, the tire model 201 having a direct tread pattern may be created according to the model creation conditions. In addition, a rim model (not shown) is created separately, and the tire model 201 with the rim model attached is created by merging the rim model with the previously created tire model 201.
On the other hand, in addition to the road surface model 202 being separately created, a fluid analysis region 203 serving as a fluid model is created (step S202).
[0036]
The rim model may be a finite element model of a deformable elastic body, or may be a model in which a part is a rigid body and the other part is an elastic body, or the entire body is a rigid body. It may be the model that became. The road surface model 202 may be a rigid body model that does not allow deformation, or may be a deformable elastic body model.
The above is the flow of model creation.
[0037]
Next, static analysis is performed by the static analysis unit 300 (step S301).
An internal pressure filling process is performed on the tire model 201 to which the rim model is attached. The internal pressure filling process is performed by calculation for applying a uniform pressure to the inner surface of the cavity region of the tire model 201 corresponding to the inner surface of the tire. It is determined whether or not this process has been performed for a predetermined analysis time, and an internal pressure filling process is performed until the predetermined analysis time has elapsed.
Further, the grounding process is performed according to the set load so that the tire model 201 subjected to the internal pressure filling process is grounded to the road surface model 202. It is determined whether or not this process has been performed for a predetermined analysis time, and the grounding process is performed until the predetermined analysis time has elapsed. The load is given as one of the rolling conditions.
As a result, the tire model 201 becomes a tire model 201 deformed by being brought into contact with the road surface model 202. In the grounding process, the grounding process may be performed using the friction coefficient of the road surface model 202 set as one of the rolling conditions.
The above is the flow of static analysis.
[0038]
Next, a rolling process is performed on the tire model 201 subjected to the grounding process (step S401).
The rolling process is a process for moving the tire model 201 from a stationary state at a predetermined traveling speed, and the method of this process is not particularly limited. For example, a predetermined rotation speed and translation speed (travel speed) are given to the tire model 201 around the tire rotation axis, and the rotation speed and translation speed are gradually increased to reach the target rotation speed and translation speed. Alternatively, the tire model 201 and the mounted rim model (not shown) are once converted into a rigid body model that does not allow deformation, and thereafter the target rotational speed and translation speed (traveling speed) are instantaneously input and given, and then The tire model 201 in a desired rolling state may be created by restoring the rigid model to a deformable tire model and a rim model.
[0039]
Next, dynamic analysis is performed on the tire model 201 in a rolling state (step S501).
FIG. 5 is a flowchart showing in detail the flow of the dynamic analysis process.
Regarding the calculation of the dynamic analysis, the tire model 201 is sequentially calculated with a predetermined time increment based on the boundary condition given to the tire model 201 by the fluid substance in the fluid analysis region 203, and the tire model is also calculated. Based on the boundary condition that 201 gives to the fluid substance in the fluid analysis region 203, the flow calculation of the fluid substance is sequentially performed at a predetermined time interval.
[0040]
First, a boundary surface between the tire model 201 and the fluid substance in the fluid analysis region 203 is calculated (step S502).
FIG. 6 is a view showing a state immediately before the tire model 201 rolling on the road surface model 202 enters the fluid analysis region 203. In the fluid analysis region 203 in FIG. 6, a 10-step region element formed by dividing the space region above the road surface model 202 into 10 in the height direction is formed. Further, the fluid substance (gray region in FIG. 7) is filled from the lowest level in contact with the road surface model 202 to the position of the third level region element. From this state, the tire model 201 enters the fluid analysis region 203. The fluid analysis region 203 is created on the road surface model 202 by an Euler mesh obtained by dividing the space region into meshes, and the fluid substance in the fluid analysis region 203 is characterized by density and bulk modulus. Is. The fluid substance may be characterized by an elastic modulus, a viscosity coefficient, or a kinematic viscosity, in addition to those characterized by density and bulk modulus.
[0041]
FIG. 7 is a diagram schematically illustrating a state where the tire model 201 enters the fluid analysis region 203 and the fluid substance is partially excluded.
Here, the numerical value described in each area element represents the volume ratio of each element area occupied by the fluid substance (gray area in FIG. 7) in each area element, and 1.0 is the fluid in the area element. Indicates that the substance is completely filled.
The boundary surface A between the fluid model composed of the fluid substance and the tire model 201 is calculated as follows.
[0042]
The calculation of the boundary surface A between the tire model 201 and the fluid model composed of the fluid substance will be described more specifically.
FIG. 8 is a flowchart showing the flow of calculation of the boundary surface between the tire model and the fluid substance, and FIGS. 9A and 9B are explanatory diagrams for explaining the calculation of the boundary surface.
First, there is an intersection where each region element in the fluid analysis region 203 intersects with the tire model 201. Or It is determined whether or not (step S600).
When it is determined that an intersection exists, a boundary surface is obtained from the intersection. Specifically, as shown in FIG. 9A, it is determined whether or not there is an intersection by the surface S of the element constituting the outer shell of the tire model 201 and each element side of each region element, and at least three ( In FIG. 9A, when the intersections of four intersections Pa to Pc) are obtained, the position of the boundary surface surrounded by the line segment connecting these intersections is calculated (step S602).
On the other hand, when it is determined that no intersection exists, it is determined whether or not the region element exists outside the tire model 201 (step S604). When the area element of the fluid analysis area 203 exists inside the tire model, the fluid substance is excluded and does not exist in the tire model 201, so that there are fluid physical quantities (flow velocity, fluid pressure, volume ratio, etc.) of the fluid substance described later. It is treated as not (step S605).
[0043]
If the determination in step S600 and step S604 is affirmative, the fluid physical quantity in the region element separated from the boundary surface with the tire model 201 is calculated (step S606).
When the fluid physical quantity is, for example, the volume ratio of the fluid substance in the region element as shown in FIG. 7, the tire model 201 enters the fluid analysis region 203, and as shown in FIG. The elements are separated by the boundary surface and become smaller as in the region F in FIG. 9B, and the volume ratio occupied by the fluid substance becomes smaller. Further, when the fluid physical quantity is, for example, the flow rate of fluid substance, fluid pressure, energy, etc., the volume ratio of the region F located outside the tire model 201 separated by the boundary surface to the original region element, and the boundary surface By calculating the value of the fluid physical quantity in the original area element before the separation, the fluid physical quantity of the fluid substance regulated by the tire model 201 entering the fluid analysis area 203 is calculated. If the determination in step S604 is affirmative, the region physical elements are not separated at the boundary surface, and the fluid physical quantity does not change.
The calculations in steps S600 to S606 are performed for each region element in the fluid analysis region 203.
[0044]
In this manner, the boundary surface between the tire model 201 and the fluid substance in the fluid analysis region 203 is calculated, and the fluid physical quantity is calculated. This calculation is examined for each region element in the fluid analysis region 203 as described above. In the present invention, as will be described later, since the fluid analysis region 203 moves in accordance with the movement of the tire model 201, it is not necessary to create a fluid analysis region that is long in the moving direction of the tire model 201 as in the conventional method. In addition, the number of elements in the region of the fluid analysis area can be reduced to a fraction of the number of elements in the fluid analysis area used in the conventional method. Therefore, the processing time required for the calculation of the boundary surface and the calculation of the fluid physical quantity performed for each region element is shortened as compared with the conventional method.
[0045]
Next, the force acting on the tire model 201 from the fluid substance in the fluid analysis region 203 is set as a boundary condition (step S503), and the deformation calculation of the rolling tire model 201 is performed based on this, and the tire model 201 is calculated. Displacement and stress are calculated (step S504).
Here, the boundary condition is set by, for example, collecting the fluid pressure of the fluid substance acting on the boundary surface as a force on the vertex of the region element forming the boundary surface, and the force aggregated on the vertex corresponds to the tire model 201. The boundary conditions of the tire model 201 are calculated so as to be given to the nodes.
[0046]
On the other hand, the tire model 201 is set as a boundary condition to the fluid material from the deformed shape of the tire model 201 that has been deformed by the fluid material by entering the fluid analysis region 203 and the speed component accompanying the rolling of the tire model 201. (Step S505).
That is, since the boundary surface between the tire model 201 and the fluid substance is set in step S502, fluid analysis of the fluid substance generated by the velocity component accompanying the rolling of the tire model 201 is performed using the boundary surface as a geometric boundary condition. A volume change amount in the space 203 is set. Further, among the region elements of the fluid analysis region 203, the fluid material has a flow velocity in the moving direction of the tire model 201 in at least the region element at the front end that is located at the front end of the fluid analysis region 203 and whose front end surface is in contact with the fluid material. In addition, a constraint condition for restricting the flow of the fluid substance is applied, and among the boundary surface of the fluid analysis area 203, the boundary condition for prohibiting the outflow and inflow of the fluid substance is provided on the side surface and the lower surface of the fluid analysis area 203. Is granted.
Based on this, flow calculation of the fluid substance is performed, and the fluid pressure, flow velocity, volume content, and the like of the fluid substance in the fluid analysis region 203 are calculated (step S506).
[0047]
Next, the fluid analysis region 203 is moved so as to follow the movement of the tire model 201 (step S507). In this case, of the boundary surface of the fluid analysis region 203, a boundary condition that allows only the inflow of fluid substance is permitted on the front end surface in the moving direction of the tire model 201, and only the outflow of fluid material is present on the rear end surface of the fluid analysis region 203. Boundary conditions that allow
Since the length of the fluid analysis region 203 in the moving direction of the tire model 201 is made short, the behavior of the stable tire model 201 that has sufficiently reached a steady state by causing the fluid analysis region 203 to follow the movement of the tire model 201. Therefore, the fluid analysis region 203 is moved so as to follow the movement of the tire model 201.
That is, the fluid analysis region 203 moves in the moving direction of the tire model 201 by a distance determined by the product of the traveling speed of the tire model 201 and the step size of a predetermined analysis time for performing dynamic analysis. Thus, the tire model 201 is always set so as to be located in the fluid analysis region 203.
The fluid analysis region 203 is moved when the tire model 201 enters the fluid analysis region 203 for a predetermined length or when the fluid in the fluid analysis region 203 is in a space sandwiched between the tire model 201 and the road surface model 202. It is best to start when the substance is filled.
[0048]
Next, a mapping process of the physical quantity (fluid physical quantity) of the fluid substance in the fluid analysis region 203 is performed (step S508).
The mapping process is performed to set the fluid physical quantity (volume content, fluid pressure, flow velocity) of the destination fluid substance in the fluid analysis region 203 that has moved according to the step size of the analysis time when performing the dynamic analysis.
[0049]
10A and 10B show one region element E in the fluid analysis region 201 before movement. ₁ And the moved area element E ₁ It is explanatory drawing which demonstrated mapping processing typically paying attention to '.
In this mapping process, the volume of the area element of the fluid analysis area 203 after the movement of the overlapping area where each area element of the fluid analysis area 203 after the movement overlaps with the area element of the fluid analysis area 203 before the movement. As a weighting coefficient, the fluid physical quantity in the area element of the flow analysis area 203 before movement is weighted and the weighted average value is used as the fluid physical quantity in each area element of the fluid analysis area 203 after movement.
[0050]
As shown in FIG. ₁ And fluid physical quantity P ₁ Region element E with ₁ And adjacent volume V ₂ And fluid physical quantity P ₂ Region element E with ₂ Is moved, and moved to the position shown in FIG. ₁ 'Is the area element E before movement ₁ And area element E ₂ Is straddling. In this case, the area element E ₁ Fluid physical quantity P ₁ 'Is the area element E after the movement ₁ 'And area element E before movement ₁ , E ₂ The ratio of the element volume of the overlapping part overlapping with (region element E after movement ₁ The ratio of the element volume of the overlapping portion to ' ₁ , E ₂ Fluid physical quantity P ₁ , P ₂ Is weighted average, and this weighted average value is moved to the area element E after moving. ₁ Fluid physical quantity P ' ₁ 'And.
That is, the area element E ₁ , E ₂ Is an area element E ₁ 'The ratio of the element volume in ₁ , Α ₂ (Α ₁ + Α ₂ = 1), the fluid physical quantity P is obtained by the following equation (1). ₁ 'Is required.
P ₁ '= Α ₁ ・ P ₁ + Α ₂ ・ P ₂ (1)
[0051]
In the example shown in FIGS. 10A and 10B, the area element after movement straddles the two area elements before movement, but in the present invention, depending on the mesh division of the fluid analysis area 203, In some cases, it extends over a plurality (n) of region elements. In this case, the above formula (1) can be expressed as the following formula (2). α _n Is the physical quantity P _n Region element E before movement with _n Is the area element E after the movement ₁ The volume ratio of '
P ₁ '= Α ₁ ・ P ₁ + Α ₂ ・ P ₂ + ...... + α _n ・ P _n (2)
Where α ₁ + Α ₂ + ...... + α _n = 1
By performing such mapping processing, using the fluid physical quantity in the fluid analysis region 203 after movement, the deformation calculation of the tire model 201 advanced by one increment of the analysis time and the calculation of the flow of fluid material are performed. be able to.
The mapping process is not necessarily limited to the process of performing weighted averaging using the ratio of the element volume of the overlapping part as a weighting coefficient. For example, the ratio of the surface area of the overlapping part instead of the element volume and the mass of the fluid substance in the overlapping part. You may use the element variable which the overlap part in area | region elements, such as a ratio and the ratio of the flow rate of a fluid substance, has. Further, the mapping process is not limited to the process based on the weighted average. At least the fluid physical quantity in each area element of the fluid analysis area 203 after movement may be processed using an element variable including the fluid physical quantity in each area element of the fluid analysis area 203 before movement.
[0052]
Next, it is determined whether or not the calculation result of the dynamic analysis satisfies a predetermined condition (step S509). Here, the condition may be whether or not the fluid physical quantity of the fluid substance after the calculation or the physical quantity after the calculation acting on the tire model 201 satisfies a preset condition, for example. It may be whether or not the analyzed time passed.
If the determination is negative, the analysis time advances by one time step, returns to step S502 again, and steps S502 to S508 are performed. Thus, steps S502 to S508 are repeatedly performed until the fluid physical quantity of the fluid substance or the physical quantity acting on the tire model 201 satisfies a predetermined condition.
At that time, using the calculation result of step S504, that is, the deformation calculation result of the tire model 201 and the fluid physical quantity in the fluid analysis region 203 after movement obtained in step S508, the analysis time advances by one step. The boundary surface of step S502 in the analysis time is set. Further, using the fluid physical quantity obtained in step S508, the boundary condition given to the tire model 201 at the analysis time advanced by one step size of the analysis time is set. Further, using the deformation calculation result of the tire model 201 obtained in step S504, a boundary condition to be given to the fluid substance at the analysis time advanced by one step size of the analysis time is set. In this way, the interference between the tire model 201 and the fluid substance in the fluid analysis region 203 is calculated.
[0053]
In step S504 and step S508, each time it is repeatedly calculated, the physical quantity of the tire model 201 and the fluid physical quantity of the fluid substance are calculated and stored in the memory 120.
As physical quantities of the tire model 201, for example, buoyancy that acts on the tire rotation axis of the tire model 201, road reaction force that the road surface model 202 acts on the tire rotation axis of the tire model 201, and between the tire model 201 and the road surface model 202 are generated. A frictional force, a contact shape of the tire model 201, a contact area, a contact pressure distribution, and the like are calculated. On the other hand, the volume of the fluid substance as the fluid physical quantity of the fluid substance ratio, In addition to the distribution of fluid pressure and flow velocity, various distributions such as the flow rate, energy density, or energy of the fluid substance are calculated.
The dynamic analysis (step S501) is performed as described above.
[0054]
In addition, by moving the fluid analysis region 203 following the movement of the tire model 201, the length of the fluid analysis region 203 in the moving direction of the tire model 203 can be shortened as compared with the conventional method.
FIGS. 11A to 11C are diagrams schematically showing a state where the tire model 201 enters the fluid analysis region 203 at the traveling speed V. FIG.
In the method of the present invention, a fluid analysis region 203 is provided in a range X around the contact portion between the tire model 201 and the road surface model 202 that greatly affects the behavior of the tire model 201, and this fluid analysis region 203 is defined as the tire model. Since the movement is performed following the movement of 201, the accuracy of the analysis result does not decrease even if the length of the fluid analysis region 203 is shortened. Moreover, since the number of area elements in the fluid analysis area 203 can be reduced, there is an advantage that the calculation process of the boundary surface performed in step S502 can be completed in a short time.
In this case, the length of the fluid analysis region 203 in the moving direction of the tire model 201 is preferably short, but if it is too short, the accuracy of the analysis result decreases. The tire model 201 is preferably 0.5 to 4 times the maximum contact length of the tire model 201 that contacts the road surface model 202 by contacting the road surface model 202. If the fluid analysis area 203 is smaller than 0.5 times, the drainage property that the tire moves while removing water on the road surface cannot be reproduced. If the fluid analysis area 203 is larger than 4 times, the scale of the fluid analysis area 203 becomes large. This is because the reduction in processing time required for analysis is reduced. Since the fluid analysis region 203 has a length in this range, the behavior of the tire when the moving tire passes through the water film can be accurately reproduced while reducing the calculation processing time, as in the conventional method. Because it can.
[0055]
On the other hand, in the conventional method shown in FIGS. 12A to 12C, the fluid analysis region is also provided in the range Y far away from the tire model 201, which has a very small influence on the behavior of the tire model 201. The calculation process of the boundary surface in the area element in the range Y is also performed, and the calculation process takes a long time.
[0056]
After the end of the dynamic analysis, the physical quantity of the tire model 201 and the fluid physical quantity of the fluid substance for each step size of each analysis time, which is the result of the dynamic analysis, are called from the memory 120 that is stored and held, and the time series data It is extracted as the represented physical quantity (step S601).
FIG. 13 is a diagram illustrating an example of the extracted physical quantity. The physical quantities shown in FIG. 13 are road surface reaction forces that the tire model 201 receives from the road surface model 202 and that acts on the tire rotation axis.
The road surface reaction force shown in FIG. 13 is that a tire model 201 that is a model of a tire for passenger cars is grounded to the road surface model 202 with a load of 4 (kN), and a fluid material having a thickness of 3 mm is formed at a traveling speed of 100 (km / hour). The road surface reaction force when entering the fluid analysis region 203. Immediately after the tire model 201 enters the fluid analysis region 203 (immediately after the analysis time of 0.2 seconds), the road surface reaction force varies greatly, but after 0.08 seconds (when the analysis time is 0.208 seconds), the road surface The reaction force asymptotically approaches 2 (kN) and is in a steady state. That is, it can be seen that the tire model 201 receives a buoyancy of approximately 2 (kN) from the road surface model 202. Such physical quantity extraction results coincide with the road surface reaction force obtained by the conventional tire performance prediction method shown in FIG.
[0057]
Finally, the tire performance is predicted using the extracted physical quantity (step S701).
For example, when the physical quantity shown in FIG. 13 is extracted, the magnitude of the road surface reaction force in the steady state is approximately 2 (kN) in this case. By comparing this road surface reaction force with a predetermined value, The superiority or inferiority of hydroplaning can be predicted.
Further, the buoyancy acting on the tire rotation axis of the tire rim model 201, the contact shape of the tire rim model 201, the contact area or the contact pressure distribution, the volume content of the fluid substance, the fluid pressure of the fluid substance, the flow velocity, the flow rate, the energy density, or It is also possible to predict tire performance by extracting various distributions such as energy as physical quantities.
[0058]
When the tire performance is predicted using the above tire simulation method, the calculation processing speed is improved as follows.
Table 1 below shows the number of tire model elements, the number of area elements in the fluid analysis region, the calculation processing speed, and the conventional method shown in FIG. 14 used when the physical quantities shown in FIG. 13 are extracted. The number of elements of the tire model, the number of area elements in the fluid analysis area, and the calculation processing speed when the same processing is performed in FIG. The calculation processing speed is represented by an index. The higher the index, the faster the calculation processing speed.
The tire models used in the method according to the present invention and the conventional method are the same finite element model, and only the number of area elements in the fluid analysis area is different. It can be seen that the calculation processing speed is improved by 65% in the method according to the present invention compared to the conventional method. The conventional method requires several tens of hours to several hundreds of hours of calculation processing time. In the method according to the present invention, the calculation processing time is about several hours to several tens of hours (about one day) due to a 65% improvement in calculation processing speed. )Shorten.
[0059]
[Table 1]

[0060]
The tire performance prediction method as described above is, for example, a tire base model and a tread pattern model that do not include the tread pattern constituting the tire model 201. The Various types are prepared in advance, and can be effectively used when efficiently selecting a combination of a tire base model and a tread pattern model having the best prediction result of tire performance from the prepared models. In addition, the tire base model and the tread and pattern model are sequentially corrected using an optimization method such as a genetic algorithm, and can be used effectively when the optimum tire model is efficiently obtained. Designing a tire that realizes the tire model selected or found in this way, designing a tire manufacturing mold for manufacturing the tire, and manufacturing a tire designed using the tire manufacturing mold Can do.
The present invention provides such a tire manufacturing method and a tire manufactured using this manufacturing method.
[0061]
In the above-described embodiment, the case where the tire model goes straight has been described. However, in the present invention, the tire model that moves on the road surface model may turn. In this case, the fluid analysis region may move two-dimensionally on the road surface model following the turning direction of the tire model. Furthermore, in the present invention, the running speed of the tire model may be accelerated and decelerated with acceleration.
In the above embodiment, the tire simulation method and the tire performance prediction method in which the tire passes over the water film provided on the road surface have been mainly described. However, the fluid substance in the present invention is limited to the water constituting the water film. Alternatively, it may be a liquid or a gas. For example, the tire performance may be predicted by simulating the air flow around the moving tire.
[0062]
The tire simulation method, tire performance prediction method, tire manufacturing method, tire, and program of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and does not depart from the spirit of the present invention. Of course, various improvements and modifications may be made.
[0063]
【The invention's effect】
As described above in detail, when reproducing the behavior of a tire moving on a road surface using a tire model, the present invention has a plurality of area elements obtained by mesh-dividing a part of the space area on the road surface model. Since the fluid analysis area filled with the fluid substance in this space area is moved according to the movement of the tire model, the length of the fluid analysis area can be shortened and the number of area elements can be reduced. The calculation processing time of the dynamic analysis for calculating the interference of the model can be shortened. This makes it possible to predict practical tire performance.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of a tire performance prediction apparatus that performs a tire simulation method and a tire performance prediction method according to the present invention.
FIG. 2 is a perspective view showing an example of various models created by the tire simulation method and tire performance prediction method of the present invention.
FIGS. 3A to 3C are diagrams for explaining the arrangement of fluid substances used in the tire simulation method and tire performance prediction method of the present invention. FIG.
FIG. 4 is a flowchart showing an example of the flow of the tire simulation and tire performance prediction method of the present invention.
FIG. 5 is a flowchart showing a flow of dynamic analysis processing performed in the tire simulation and tire performance prediction method of the present invention.
FIG. 6 is a diagram showing a state immediately before the tire model enters the fluid analysis region, which is performed in the tire simulation and tire performance prediction method of the present invention.
FIG. 7 is a diagram schematically illustrating a state in which a tire model enters a fluid analysis region and fluid substances are partially excluded.
FIG. 8 is a flowchart showing a flow of calculation of an interface between a tire model and a fluid substance.
FIGS. 9A and 9B are explanatory diagrams for explaining calculation of a boundary surface.
FIGS. 10A and 10B are explanatory views schematically illustrating mapping processing performed in the tire simulation and tire performance prediction method of the present invention.
FIGS. 11A to 11C are diagrams schematically illustrating a state in which a tire model enters a fluid analysis region set by a tire simulation and a tire performance prediction method according to the present invention.
FIGS. 12A to 12C are diagrams schematically illustrating a state in which a tire model enters a fluid analysis region set by a conventional tire performance prediction method.
FIG. 13 is a diagram showing an example of physical quantities extracted by the tire performance prediction method of the present invention.
FIG. 14 is a perspective view showing an example of a tire model and a fluid model created by a conventional tire performance prediction method.
[Explanation of symbols]
100 Tire performance prediction device
110 CPU
120 memory
200 Model creation department
201 tire model
202 Road surface model
203 Fluid Analysis Area
300 Static analysis part
400 Rolling processing part
500 Dynamic analysis part
600 Physical quantity extraction unit
700 Tire Performance Prediction Unit

Claims (17)

A tire simulation method that reproduces the behavior of a tire traveling on a road surface,
A road surface model that reproduces the road surface, a tire model that moves on the road surface model, and a plurality of area elements obtained by dividing a part of the space area on the road surface model into meshes. A model creation step for creating a fluid model to be a target of calculation of the flow of the fluid substance, comprising a fluid analysis region filled with the fluid substance of
When the tire model enters the fluid analysis region, a boundary condition that the tire model gives to the fluid substance in the fluid analysis region is set, and based on the boundary condition, the fluid model including the fluid analysis region a fluid calculation step of calculating the flow of said fluid material,
The fluid model comprising the fluid analysis region for calculating the flow of the fluid substance in the fluid calculation step with respect to the road surface model in accordance with movement of the tire model rolling on the road surface model in a tire traveling direction. An analysis region moving step for moving the entire tire traveling direction ;
When the tire model enters the fluid analysis region, a boundary condition given to the tire model by the flow of the fluid substance in the fluid analysis region is set, and the deformation of the tire model is calculated based on the boundary condition. Deformation calculation step;
A tire simulation method comprising: the fluid calculation step, the analysis region movement step, and a repetition step of repeatedly performing the deformation calculation step.   In the repetition step, the boundary condition in the next deformation calculation step is set based on the physical quantity of the fluid substance obtained in the fluid calculation step, and the deformation of the tire model obtained in the deformation calculation step is performed. The tire simulation method according to claim 1, wherein the boundary condition in the next fluid calculation step is set based on.   In the analysis area moving step, the physical quantity of the fluid substance in each area element of the fluid analysis area after movement is generated by mapping the physical quantity of the fluid substance in each area element of the fluid analysis area before movement. The tire simulation method according to claim 1 or 2.   In the mapping process, a physical quantity in each area element of the fluid analysis area before movement is set by using, as a weighting factor, an element variable having an overlapping portion where the area element of the fluid analysis area after movement and the area element of the fluid analysis area before movement overlap The tire simulation method according to claim 3, wherein the weighted average processing is performed.   5. The tire simulation method according to claim 4, wherein the element variable is a ratio of an element volume of the overlapped portion to a region element in the fluid analysis region after movement overlapping with a region element in the fluid analysis region before movement.   The physical quantity of the fluid substance includes at least one of a fluid pressure of the fluid substance, a flow rate of the fluid substance, and a volume content of the fluid substance included in the region element. The tire simulation method described in 1.   The tire simulation method according to claim 1, wherein, in the fluid calculation step and the analysis region movement step, a gravitational acceleration is applied to the fluid material to calculate a flow of the fluid material. In the analysis region moving step, among the boundary surfaces of the fluid analysis region, the front end surface in the moving direction of the tire model has a boundary condition that only allows the inflow of the fluid substance, and the rear end surface of the fluid analysis region Giving boundary conditions that allow only the outflow of the fluid substance;
In the fluid calculation step, among the region elements, the fluid substance is positioned at the front end of the fluid analysis region and the front end surface is in contact with the fluid substance, and the fluid substance has a flow velocity in the moving direction of the tire model. The tire simulation method according to claim 1, wherein a restraint condition for restraining the flow of the fluid substance is provided so as to have the following.   The tire simulation method according to claim 8, wherein a boundary condition for prohibiting outflow and inflow of the fluid substance is applied to a side surface and a lower surface of the fluid analysis region among boundary surfaces of the fluid analysis region.   The length of the fluid analysis region in the moving direction of the tire model is the maximum contact length of the tire model in the moving direction when the tire model is in contact with a portion of the road surface model without the fluid analyzing region. It is 0.5 times or more and 4 times or less, The tire simulation method of any one of Claims 1-9.   The tire simulation method according to claim 1, wherein the tire model is a finite element model created by dividing a tire constituent member into a finite number of elements. Performing the tire simulation method according to any one of claims 1 to 11 to calculate at least one of a physical quantity acting on the tire model and a physical quantity of the fluid substance;
Predicting tire performance based on the calculated physical quantity, and a tire performance prediction method.   A tire manufacturing method comprising manufacturing a tire designed using the tire performance prediction method according to claim 12. A computer-executable program that causes a computer to execute a tire simulation method that reproduces the behavior of a tire traveling on a road surface,
A road surface model that reproduces the road surface, a tire model that moves on the road surface model, and a plurality of area elements created by dividing a part of the space area on the road surface model into meshes, and the predetermined space area A fluid analysis area filled with the fluid substance, and a fluid model to be calculated for the flow of the fluid substance, and a model creation procedure for causing the computing means to create the computer,
When the tire model enters the fluid analysis region, a boundary condition that the tire model gives to the fluid substance in the fluid analysis region is set, and based on the boundary condition, the fluid model including the fluid analysis region a fluid calculation procedure for calculating the flow of said fluid material to said computing means,
The fluid model comprising the fluid analysis region for calculating the flow of the fluid substance in the fluid calculation procedure with respect to the road surface model in accordance with movement of the tire model rolling on the road surface model in a tire traveling direction. An analysis region moving procedure for causing the calculating means to move the entire tire traveling direction ;
When the tire model enters the fluid analysis region, a boundary condition that the flow of the fluid substance in the fluid analysis region gives the tire model is set, and deformation of the tire model is calculated based on the boundary condition. A deformation calculation procedure for causing the means to calculate,
A program characterized by causing the fluid calculation procedure, the analysis region moving procedure, and the deformation calculation procedure to be repeated. In the analysis area moving procedure, the physical quantity of the fluid substance in each area element of the fluid analysis area after movement is generated by mapping the physical quantity of the fluid substance in each area element of the fluid analysis area before movement. The program according to claim 14. In the mapping process, a physical quantity in each area element of the fluid analysis area before movement is set by using, as a weighting factor, an element variable having an overlapping portion where the area element of the fluid analysis area after movement and the area element of the fluid analysis area before movement overlap The program according to claim 15, which is a weighted average process. The length of the fluid analysis region in the moving direction of the tire model is the maximum contact length of the tire model in the moving direction when the tire model is in contact with a portion of the road surface model without the fluid analyzing region. The program according to any one of claims 14 to 16, wherein the program is 0.5 to 4 times.

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