Cost calculation system, method and program

Abstract

To provide a system capable of calculating a cost price of a tire using material cost price data and a finite element model.SOLUTION: A cost price calculation system of an embodiment comprises a database which stores data necessary to calculate a cost price of a finished product, and a calculation unit which calculates the cost price of the finished product using the data in the database. The calculation unit calculates a cost price of a tire as a finished product using a volume of each tire configuration member calculated on the basis of a finite element model of a tire and a material cost price of each tire configuration member stored in the database.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cost calculation system, a method, and a program. [Background technology]

[0002] There is a method in which a database is prepared in advance in which data such as costs for various parts is stored, and when a user selects multiple parts for producing a finished product, the cost of the finished product is calculated based on the cost data for each part stored in the database (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-182732 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the material costs of each component that constitutes a tire may be managed as data, and a finite element model may be created to perform a tire simulation.

[0005] Therefore, an object of the present invention is to provide a system, method, and program capable of calculating the cost of a tire by utilizing such material cost data and a finite element model. [Means for solving the problem]

[0006] A cost calculation system according to an embodiment includes a database of data necessary for calculating the cost of a finished product, and a calculation unit that calculates the cost of the finished product using data from the database, the database including data on material costs for a plurality of materials, the calculation unit calculating the cost of the finished product, which is a tire made of a plurality of tire constituent members made of different materials, and the calculation unit calculating the cost of the finished product, which is a tire, using the volume of each tire constituent member determined based on a finite element model of the tire and the material cost of the material of each tire constituent member stored in the database. The finite element model is a two-dimensional model of a tire width direction cross section, the calculation unit calculates the volume of each tire constituent member when the two-dimensional model is expanded one revolution in the tire circumferential direction, and calculates the tire cost using the volume, and for tread rubber, which is one of the tire constituent members, the calculation unit calculates the volume of the tread rubber by excluding the volume of grooves that do not appear in the two-dimensional model from the volume of the tread rubber when the two-dimensional model is expanded one revolution in the tire circumferential direction. .

[0007] In addition, a cost calculation method of an embodiment is a cost calculation method in which a computer executes a step of acquiring data necessary for cost calculation from a database, and a step of calculating the cost using the data acquired from the database, the database includes data on material costs for a plurality of materials, and the cost calculation method is a method in which the computer calculates the cost of a tire composed of a plurality of tire constituent members made of different materials, and is characterized in that the computer executes a step of determining the volume of each tire constituent member based on a finite element model of the tire, a step of acquiring the material costs of the materials of each tire constituent member as the data from the database, and a step of calculating the cost of the tire using the volume and material costs of each tire constituent member. The finite element model is a two-dimensional model of a tire width direction cross section, the computer calculates the volume of each tire constituent member when the two-dimensional model is expanded in the tire circumferential direction once, and calculates the tire cost using the volume, and for tread rubber, which is one of the tire constituent members, the computer calculates the volume of the tread rubber by excluding the volume of grooves that do not appear in the two-dimensional model from the volume of the tread rubber when the two-dimensional model is expanded in the tire circumferential direction once. .

[0008] In addition, the program of the embodiment includes On the computer, Follow the above method to make This is a program for Effect of the Invention

[0009] According to the cost calculation system, method, and program of the embodiment, the cost of a tire can be calculated by utilizing material cost data and a finite element model. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a cost calculation system. [Diagram 2] A diagram showing the database configuration. [Diagram 3] FIG. 2 shows a two-dimensional tire model. [Figure 4] 1 is a flowchart of a cost calculation method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The embodiments will be described with reference to the drawings. Note that the embodiments described below are merely examples, and any appropriate modifications that do not depart from the gist of the present invention are included in the scope of the present invention.

[0012] The cost calculation system 10 of the embodiment is a system that calculates the cost of a tire based on a finite element model of the tire created for simulation or the like and the material costs of each tire component stored in a database. Here, the tire components refer to components that make up the tire, such as tread rubber and sidewall rubber.

[0013] 1, a cost calculation system 10 according to an embodiment is a computer system including a CPU 11, a memory 12, etc. An input device 30 such as a keyboard and an output device 31 such as a display are connected to the cost calculation system 10.

[0014] The memory 12 stores a program 13 for executing the cost calculation method of this embodiment, a database 14 in which data necessary for cost calculation is stored, and the like. The CPU 11 reads and executes the program 13 from the memory 12, thereby functioning as a model acquisition unit 16, a member volume calculation unit 17, and a cost calculation unit 18, which will be described later. The member volume calculation unit 17 and the cost calculation unit 18 can be collectively referred to as a calculation unit.

[0015] As shown in FIG. 2, database 14 stores the numbers of the materials (rubbers) of the tire constituent members (hereinafter referred to as "compound numbers") and data such as the physical property values, density, and material cost of each material, linked to each other. Here, the physical property values ​​include those required for simulations using a finite element model, such as Poisson's ratio and elastic modulus. The material cost is the price per unit weight of the material. Various types of rubber with different compounds are assumed as materials. The density and material cost data are used to calculate the cost of the tire, and the physical property values ​​are used for finite element analysis.

[0016] The model acquisition unit 16 acquires a tire model. The tire model acquired here is a finite element model in which the tire is divided into a finite number of elements. For each element, an element number, a node number, a node coordinate, a material property value (e.g., density, Young's modulus, Poisson's ratio, etc.) and the like can be set. As the finite element model acquired by the model acquisition unit 16, a model created in advance for simulating a tire by finite element analysis can be used.

[0017] The finite element model in this embodiment is a two-dimensional model of a tire widthwise cross section (hereinafter referred to as a "two-dimensional tire model 20") as shown in Fig. 3. The two-dimensional tire model 20 is a model of one side in the tire width direction. However, a model that includes both sides in the tire width direction may be obtained as the two-dimensional tire model.

[0018] The tire two-dimensional model 20 includes tire components such as beads 21, carcass ply 22, inner liner 23, belt 24, tread rubber 25, sidewall rubber 26, and rim strip 27. A main groove 28 appears in the tread rubber 25. In an actual tire, the main groove 28 completes one revolution in the tire circumferential direction. The portion of the tread rubber 25 sandwiched between the two main grooves 28 and the portion sandwiched between the main groove 28 and the ground contact edge are called land portions.

[0019] Although not shown in the tire two-dimensional model 20, various grooves such as lateral grooves extending in the tire width direction and sipes closing within the land portion are formed in the land portion of an actual tire. The volume V of the tread rubber 25 when it is assumed that there are no grooves (grooves other than the main grooves 28) that do not appear in the tire two-dimensional model 20 is p The total volume V of grooves that do not appear in the tire two-dimensional model 20 q is defined as the slit void ratio R. In other words, the slit void ratio R is calculated by the following formula.

[0020]

number

[0021] The member volume calculation unit 17 calculates the volume of each tire constituent member based on the two-dimensional tire model 20 acquired by the model acquisition unit 16. The volume of each tire constituent member is calculated by assuming that the two-dimensional tire model 20 is developed once in the tire circumferential direction.

[0022] As an example, the volume of a tire component can be calculated using the following integral formula:

[0023]

number

[0024] Here, x is the coordinate in the tire axial direction, a is the coordinate on the x-axis of the end of the tire constituent member on one side in the tire axial direction, b is the coordinate on the x-axis of the end of the tire constituent member on the other side in the tire axial direction, f(x) is a function representing the curve of the tire constituent member on the tire radially outer side on the tire two-dimensional model 20, and g(x) is a function representing the curve of the tire constituent member on the tire radially inner side on the tire two-dimensional model 20. For reference, f(x) and g(x) when calculating the volumes of two belts 24 are shown by thick lines in Fig. 3. Coordinate x is also shown in Fig. 3.

[0025] As another example, there is a method of finding the three-dimensional volume of each element of the tire two-dimensional model 20 by rotating it once around the tire rotation axis, and then finding the volume of the tire constituent member by adding up the volumes of all the elements that make up the tire constituent member. Specifically, first, the volume of each element on the tire two-dimensional model 20 when rotated once around the tire rotation axis is calculated using the following formula using the Pappus-Guldin theorem.

[0026]

number

[0027] Here, R m is the distance from the tire rotation axis to the center of gravity of the mth element, S m is the area of ​​the mth element, v m is the volume of the m-th element. Note that the distance R from the tire rotation axis to the center of gravity of the element is found from the center of gravity coordinates, which are found from the nodal coordinates. The volume of the tire constituent member can be calculated by adding up the volumes of each element calculated in this way using the following formula.

[0028]

number

[0029] Here, j is the number of elements constituting the tire constituent member.

[0030] When the two-dimensional tire model 20 is a model of only one side in the tire width direction, the volume of the tire constituent members can be calculated by doubling the volume V calculated by the formulas 2, 3, and 4. When the two-dimensional tire model is a model of both sides in the tire width direction, the volume V calculated by the formulas 2, 3, and 4 is the volume of the tire constituent members.

[0031] By the way, the volume V of the tread rubber 25 tWhen calculating the volume of the tread rubber 25, if it is assumed that the two-dimensional model of the tread rubber 25 is expanded in the tire circumferential direction, the volume of various grooves (e.g., lateral grooves and sipes) that do not appear in the two-dimensional model (i.e., the volume of the portion where no rubber actually exists) will be included in the calculation of the volume of the tread rubber 25. To prevent this, the member volume calculation unit 17 calculates the volume of the tread rubber 25 by expanding the tire two-dimensional model 20 once in the tire circumferential direction (the above-mentioned V p The volume of each of the grooves not shown in the 2D model (the same volume as the above V q ) to calculate a more accurate volume of the tread rubber 25.

[0032] Specifically, the component volume calculation unit 17 calculates the accurate volume V of the tread rubber 25 by the following formula: t Calculate.

[0033]

number

[0034] However, in reality, the volume of each of the above grooves V q In this embodiment, the member volume calculation unit 17 calculates the accurate volume V of the tread rubber 25 by the following formula: t Calculate.

[0035]

number

[0036] The cost calculation unit 18 calculates the cost of the tire from the material cost of each tire constituent member read from the database 14 and the volume of each tire constituent member calculated by the member volume calculation unit 17. In detail, the cost calculation unit 18 calculates the cost of the tire constituent member by multiplying the volume of the tire constituent member by the material density and material cost of the tire constituent member, and calculates the cost of the tire by adding up the costs of all the tire constituent members. That is, the cost of the tire is calculated by the following formula.

[0037]

number

[0038] Here, Y is the cost of the tire (yen), V n is the volume of the nth tire component (m 3 ), ρ n is the material density of the nth tire component (kg / m 3 ), c n is the material cost (yen / kg), and i is the number of tire components that make up one tire.

[0039] If the database 14 stores only data on the material of the rubber components and does not contain data on the materials of components other than the rubber components, such as steel cords and organic fiber cords, the accurate cost of the tire cannot be calculated only by the formula 7. In that case, a more accurate cost of the tire can be calculated by adding the costs of the components other than the rubber components to the cost Y calculated by the formula 7.

[0040] Moreover, the physical property values ​​in the database 14 are used in the simulation by the finite element analysis, and are not used in the calculation of the tire cost.

[0041] A method for calculating the cost of a tire using the cost calculation system 10 will be described with reference to the flowchart of FIG.

[0042] First, the model acquisition unit 16 acquires a two-dimensional tire model 20, which is a finite element model (S1). The two-dimensional tire model 20 is created from, for example, a two-dimensional CAD drawing of a tire, and is stored in advance in the memory 12 or the like.

[0043] Next, a blending number is obtained from the database 14 for the two-dimensional tire model 20, which is a finite element model (S2). Specifically, the user operates the input device 30 to assign a blending number stored in the database 14 to each element of the finite element model. This links each element to the physical property value, density, and material cost linked to the blending number. Since there are multiple elements for one tire constituent member, the same blending number is assigned to multiple elements belonging to the same tire constituent member. Note that the finite element model becomes usable for simulation by assigning physical property values ​​to each element. A description of the simulation will be omitted here.

[0044] Next, the member volume calculation unit 17 calculates the volume of each tire component based on the tire two-dimensional model 20 acquired by the model acquisition unit 16 (S3). At this time, the member volume calculation unit 17 calculates the volume V of the tread rubber obtained by developing the two-dimensional model in the tire circumferential direction using the slit void ratio R. p From the above, the volume of various grooves that do not appear in the 2D model, V q The exact volume of the tread rubber 25, except for V t The slit void ratio R is input by the user through the input device 30.

[0045] Next, the cost calculation unit 18 calculates the cost of the tire based on the volume, density and material cost of each tire component (S4). At this time, the cost calculation unit 18 reads the cost of the material from the database 14 based on the blend number assigned in step S2 and uses it for the calculation.

[0046] Next, the cost calculation unit 18 outputs the calculation result to the output device 31 (S5).

[0047] As described above, the cost calculation system 10 of the present embodiment calculates the cost of a tire as a finished product by using the volume of each tire constituent member determined based on the finite element model of the tire and the material cost of each tire constituent member stored in the database 14. This makes it possible to calculate the cost of a tire by utilizing the managed material cost data and the finite element model created for the simulation.

[0048] In addition, the finite element model of this embodiment is a two-dimensional model of a tire widthwise cross section, but the component volume calculation unit 17 calculates the volume of each tire component when the two-dimensional model is expanded once in the tire circumferential direction, thereby making it possible to calculate the volume of each tire component within one entire tire. Then, the cost calculation unit 18 can calculate the cost of the tire using the volume. Therefore, even if only a two-dimensional model is available as the finite element model, the cost of the tire can be calculated. Also, since there is no need to create a three-dimensional model just to calculate the cost of the tire, the cost can be calculated in a short time.

[0049] Furthermore, the component volume calculation unit 17 calculates the final volume of the tread rubber 25 from the volume of the tread rubber 25 when the two-dimensional model is developed once in the tire circumferential direction, excluding the volume of grooves that do not appear in the two-dimensional model. This makes it possible to more accurately calculate the volume of the tread rubber 25, and therefore to more accurately calculate the cost price of the tire.

[0050] As described above, the cost calculation method of this embodiment includes the steps of determining the volume of each tire constituent member based on the finite element model of the tire, acquiring the material cost of each tire constituent member from the database 14, and calculating the tire cost using the volume and material cost of each tire constituent member. This method makes it possible to calculate the tire cost by utilizing managed material cost data and a finite element model created for the simulation.

[0051] Various modifications can be made to the above embodiment, and examples of such modifications will be described below.

[0052] <Change Example 1> The finite element model acquired by the model acquisition unit 16 may be a three-dimensional model of the entire tire. In this case, the member volume calculation unit 17 can calculate the volume of each tire component from the three-dimensional model without performing calculations to expand the two-dimensional model in the tire circumferential direction as in the above embodiment. In this case, the volume of grooves and land portions whose shapes change three-dimensionally, such as three-dimensional sipes whose shapes change in the depth direction, can be accurately calculated, and the volume of the tread rubber 25 can be accurately calculated.

[0053] <Change Example 2> There is no limitation on the specific form of use of the cost calculation system 10. For example, the cost calculation system 10 may be provided in a server, and a plurality of client computers may be connected to the server via a network, so that each client computer can calculate the cost of a tire.

[0054] <Change Example 3> In the above embodiment, the cost is calculated in yen, but the cost calculation unit 18 may calculate the cost in another currency. Also, the cost calculation unit 18 may calculate the cost in one currency and then convert it into another currency.

[0055] In addition, because the country in which each material is produced is different, the currency of the material cost may differ for each material in the database 14, such as the cost of one material being in yen and the cost of another material being in dollars. In such a case, the cost calculation unit 18 calculates the cost of the tire using the following formula.

[0056]

number

[0057] Here, a n is the cost of the nth tire component (c nThis is the coefficient used to convert the currency of the cost (Y) to the currency of the cost to be calculated.

[0058] <Change Example 4> The method for calculating the cost of the tread rubber 25 is to calculate the exact volume V of the tread rubber 25 as in the above embodiment. t After calculating V t to the material density ρ n and material cost c n The calculation method is not limited to multiplying by

[0059] For example, first, the component volume calculation unit 17 calculates the volume V of the tread rubber 25 by expanding the tire two-dimensional model 20 in the tire circumferential direction. p Next, the cost calculation unit 18 calculates the volume V p to the material density ρ n and material cost c n By multiplying by , the tentative cost Y ignoring the existence of various grooves that do not appear in the tire two-dimensional model 20 is obtained. 1 Next, the cost calculation unit 18 calculates the accurate cost Y using the slit void ratio R according to the following formula: 2 Calculate.

[0060]

number

[0061] <Change Example 5> The database 14 may also include data on materials other than rubber members, such as steel cords and organic fiber cords. In that case, the accurate cost of the tire can be calculated using the formula (7). [Explanation of symbols]

[0062] 10...cost calculation system, 11...CPU, 12...memory, 13...program, 14...database, 16...model acquisition unit, 17...component volume calculation unit, 18...cost calculation unit, 20...tire two-dimensional model, 21...bead, 22...carcass ply, 23...inner liner, 24...belt, 25...tread rubber, 26...sidewall rubber, 27...rim strip, 28...main groove, 30...input device, 31...output device

Claims

1. A cost calculation system having a database of data necessary for calculating the cost of a finished product, and a calculation unit that calculates the cost of the finished product using data from the database, the database includes material cost data for a plurality of materials; The calculation unit calculates a cost of the finished product, which is a tire made of a plurality of tire constituent members made of different materials, the calculation unit calculates a cost of the tire as a finished product by using a volume of each tire constituent member obtained based on a finite element model of the tire and a material cost of each tire constituent member stored in the database, the finite element model is a two-dimensional model of a tire width direction cross section, the calculation unit calculates a volume of each tire constituent member when the two-dimensional model is expanded once in the tire circumferential direction, and calculates a cost of the tire using the volume; With regard to tread rubber, which is one of the tire constituent components, the calculation unit determines the volume of the tread rubber by excluding the volume of grooves that do not appear in the two-dimensional model from the volume of the tread rubber when the two-dimensional model is expanded once in the circumferential direction of the tire.

2. A cost calculation method, comprising the steps of: acquiring data necessary for cost calculation from a database; and calculating a cost using the data acquired from the database, The database includes data on material costs for a plurality of materials; The cost calculation method is a method in which the computer calculates a cost of a tire made of a plurality of tire constituent members made of different materials, The computer, determining a volume of each tire component based on a finite element model of the tire; acquiring a material cost of each tire component as the data from the database; Calculating the cost of the tire using the volume and material cost of each tire component; The present invention is characterized in that: the finite element model is a two-dimensional model of a tire width direction cross section, the computer calculates a volume of each tire component when the two-dimensional model is expanded once in the tire circumferential direction, and calculates the tire cost using the volume; With regard to tread rubber, which is one of the tire constituent components, the computer calculates the volume of the tread rubber by subtracting the volume of grooves that do not appear in the two-dimensional model from the volume of the tread rubber when the two-dimensional model is expanded once in the circumferential direction of the tire.

3. A program for causing a computer to execute the method of claim 2.

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