Design program, design device, and design method

Abstract

To provide a design program, a designing device, and a designing method capable of designing a coil spring that satisfies a request regardless of a cross section and pitch of a wire.SOLUTION: A design program allows a computer to execute a setting of a restriction condition set on the basis of, characteristics of a coil spring, a setting of an objective function for showing a design goal of the coil spring, creation of an analysis model for calculating characteristics of a coil spring, calculation of characteristics on the basis of an analysis model for each design proposal comprising multiple design variables including a parameter for expressing a wire sectional shape of a coil spring and a distance between wires, determination of whether characteristics of each design proposal satisfy restriction conditions, and selection of a design proposal satisfying the objective function from among design proposals determined to satisfy restriction conditions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a design program, a design device, and a design method. [Background technology]

[0002] The design of structures is based on analysis results obtained by inputting design information (see, for example, Patent Document 1). Among structures, coil springs have traditionally been designed based on shear stress analysis results, considering torsional moment and shear stress even when ignoring bending stress, in order to address actual deformation and stress conditions. However, with the recent trend toward higher stress in coil springs, coil springs with larger pitches are now being used, making it impossible to ignore the effects of bending stress. Furthermore, during the design phase, it is necessary to confirm the stress conditions under dynamic behavior in order to understand the stress conditions under actual use. Regarding the stress conditions under dynamic behavior, Non-Patent Document 1 clearly shows the distribution of cross-sectional forces and cross-sectional moments along the wire axis, taking into account the influence of the ends of the coil springs during compression. It discloses that the maximum torsional moment occurs at a position (3 / 4)π from the base of the free coil, which coincides with the actual breakage location. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6565285 [Non-patent literature]

[0004] [Non-Patent Document 1] Static and Dynamic Behavior of Coil Springs, Hiroshi Shimizu et al., Transactions of the Japan Society of Mechanical Engineers, Vol. 27, No. 179, 1119-1129 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, wires with various cross sections are used for coil springs, and the characteristics of the manufactured coil springs differ depending on the cross section and the winding interval (pitch) of the wire. However, Non-Patent Document 1 is limited to coil springs in which wires with circular cross sections are wound at a fixed pitch, and does not take into consideration coil springs that use wires with other cross-sectional shapes or coil springs with different pitches.

[0006] The present invention has been made in view of the above, and an object of the present invention is to provide a design program, a design device, and a design method that are capable of designing a coil spring that meets requirements regardless of the cross section or pitch of the wire. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, a design program according to the present invention causes a computer to execute the following steps: set constraint conditions based on the characteristics of a coil spring; set an objective function indicating a design target of the coil spring; create an analytical model for calculating the characteristics of the coil spring; calculate characteristics based on the analytical model for each design proposal consisting of a plurality of design variables including parameters expressing the cross-sectional shape of wires of the coil spring and the distance between wires; determine whether the characteristics of each design proposal satisfy the constraint conditions; and select a design proposal that satisfies the objective function from among the design proposals that are determined to satisfy the constraint conditions. The parameters expressing the wire cross-sectional shape are set for the wire cross-section using an orthogonal coordinate system with the center position of the wire cross-section as the origin, and the parameters expressing the wire cross-sectional shape include the coordinate of the center position of a circle tangent to the outer edge of the wire cross-section set on the wire cross-section, the circle diameter consisting of the lengths of the major axis and the minor axis of the circle, the coordinate of the tangent point between the outer edge of the wire cross-section and the circle, and the orientation of the circle. The present invention is characterized in that the following is executed.

[0010] Furthermore, a design device according to the present invention includes an analytical model creation unit that creates an analytical model for calculating characteristics of a coil spring; a calculation unit that calculates characteristics based on the analytical model for each design proposal made up of a plurality of design variables including parameters that express a wire cross-sectional shape of the coil spring and a distance between wires; a determination unit that determines whether the characteristics of each design proposal satisfy constraint conditions set based on the characteristics of the coil spring; and a selection unit that selects a design proposal that satisfies an objective function that indicates a design goal of the coil spring from among the design proposals that have been determined to satisfy the constraint conditions. The parameters expressing the wire cross-sectional shape are set for the wire cross-section using an orthogonal coordinate system with the center position of the wire cross-section as the origin, and the parameters expressing the wire cross-sectional shape include the coordinate of the center position of a circle tangent to the outer edge of the wire cross-section set on the wire cross-section, the circle diameter consisting of the lengths of the major axis and the minor axis of the circle, the coordinate of the tangent point between the outer edge of the wire cross-section and the circle, and the orientation of the circle.It is characterized by:

[0011] Furthermore, in a design method according to the present invention, a design device for selecting design proposals for a coil spring sets constraint conditions based on the characteristics of the coil spring, sets an objective function indicating a design target for the coil spring, creates an analytical model for calculating the characteristics of the coil spring, calculates characteristics based on the analytical model for each design proposal consisting of a plurality of design variables including parameters expressing the cross-sectional shape of wires of the coil spring and the distance between wires, determines whether the characteristics of each design proposal satisfy the constraint conditions, and selects a design proposal that satisfies the objective function from among the design proposals determined to satisfy the constraint conditions. death , The parameters expressing the wire cross-sectional shape are set for the wire cross-section using an orthogonal coordinate system with the center position of the wire cross-section as the origin, and the parameters expressing the wire cross-sectional shape include the coordinate of the center position of a circle tangent to the outer edge of the wire cross-section set in the wire cross-section, a circle diameter consisting of the lengths of the major axis and the minor axis of the circle, the coordinate of the tangent point between the outer edge of the wire cross-section and the circle, and the orientation of the circle. It is characterized by: [Effects of the Invention]

[0012] According to the present invention, it is possible to design a coil spring that satisfies requirements regardless of the cross section or pitch of the wire. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a design apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram (part 1) for explaining the definition of the basic shape of a coil spring in one embodiment of the present invention. [Figure 3] FIG. 3 is a diagram (part 2) for explaining the definition of the basic shape of a coil spring in one embodiment of the present invention. [Figure 4] FIG. 4 is a diagram (part 1) showing an example of a coil spring. [Figure 5] FIG. 5 is a diagram (part 2) showing an example of a coil spring. [Figure 6] FIG. 6 is a diagram (part 1) for explaining parameters that represent the cross-sectional shape of the wire of a coil spring. [Figure 7] FIG. 7 is a diagram (part 2) for explaining parameters that represent the cross-sectional shape of the wire of a coil spring. [Figure 8] FIG. 8 is a diagram (part 3) for explaining parameters that represent the cross-sectional shape of the wire of a coil spring. [Figure 9] FIG. 9 is a flowchart for explaining an outline of a method for selecting an optimal design plan performed by a design apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as "embodiments") will be described with reference to the accompanying drawings. Note that the drawings are schematic, and the relationship between the thickness and width of each part, the thickness ratio of each part, etc. may differ from the actual ones, and the drawings may also include parts with different dimensional relationships and ratios.

[0015] (Embodiment) Fig. 1 is a block diagram showing the schematic configuration of a design device according to one embodiment of the present invention. The design device 1 shown in Fig. 1 determines an optimal design proposal from a group of design proposals for a coil spring, and is a device that provides CAE functions to support product design and development by performing analysis and simulation on a product virtually modeled on a computer. The design device 1 has an input unit 11, an analysis model creation unit 12, a calculation unit 13, a determination unit 14, a selection unit 15, an output unit 16, a memory unit 17, and a control unit 18.

[0016] The input unit 11 receives input of various signals related to the operation of the design device 1. The input unit 11 is configured using a keyboard, a mouse, a switch, a touch panel, and the like.

[0017] The analytical model creation unit 12 references the storage unit 17, executes a program for creating an analytical model, and creates the analytical model.

[0018] The calculation unit 13 inputs design variables into the analysis model and calculates the characteristics of a virtual coil spring model that can be created using the design variables. The calculation unit 13 calculates the characteristics of the virtual model using, for example, FEM (Finite Element Method). The design variables include parameters necessary for designing a coil spring, such as the cross-sectional shape of the wire and the pitch of the coil spring. A plurality of design variables necessary for designing one coil spring form a set, and a design proposal is constructed using this set of design variables.

[0019] Here, the design variables will be described with reference to Figs. 2 to 8. First, the definition of the basic shape of a coil spring will be described. Figs. 2 and 3 are diagrams for explaining the definition of the basic shape of a coil spring in one embodiment of the present invention. Figs. 4 and 5 are diagrams showing an example of a coil spring. Figs. 3 to 5 show an example in which the shape of the wire cross section 120 is circular.

[0020] As shown in FIG. 2, the coil spring 100 is formed by spirally winding a wire. Here, a line extending along the center of the wire is defined as a center line, and a cross section cut along a plane perpendicular to this center line is defined as a wire cross section. Specifically, as shown in FIG. 3, the coil spring 100 has a center line 110 that passes through multiple centers 111 positioned at a predetermined length interval and extends along each of the wire centers 111, and a wire cross section 120 at, for example, the end of the wire, cut along a plane perpendicular to the center line 110. Here, one turn of the center line 110 is defined as one revolution in the winding direction, and the number of turns is counted as the number of turns. For example, the position where the wire (center line) has made three revolutions from one end is defined as the third turn. The basic shape of a coil spring is defined by associating the center line coordinates and the wire cross-sectional shape with the number of turns.

[0021] For coil springs with a circular wire cross section, in addition to defining the basic shape, SettingThe design variables set are the number of turns, the wire diameter (wire diameter), the average coil diameter, and the distance between center lines (pitch). A single design proposal is created by combining these design variables. For example, for the coil spring 101 shown in FIG. 4, the number of turns is set to 5, the wire diameter is set to 3.2, the average coil diameter is set to 24, and the distance between center lines is set to 5.2. For the coil spring 102 shown in FIG. 5, the number of turns is set to 10, the wire diameter is set to 2.2, the average coil diameter is set to 20, and the distance between center lines is set to 2.7. Note that, in the case of a shape other than a circle, the diameter of the wire is set, for example, as the diameter of the circumscribing circle circumscribing the cross section of the wire.

[0022] Here, parameters that represent the wire cross-sectional shape will be described with reference to Figs. 6 to 8. Figs. 6 to 8 are diagrams for explaining parameters that represent the wire cross-sectional shape of a coil spring. First, as shown in Fig. 6, for the wire cross-section, an orthogonal coordinate system is set with the center (center of gravity) position P0 of the wire cross-section as the origin, and the X and Y directions that are orthogonal to each other. Also, for the wire cross-section, a circle (including an ellipse, a perfect circle, or an oval) that is tangent to the outer edge of the wire cross-section is set. For example, as shown in Fig. 6, of the outer edge consisting of two sets (four) of straight line sections, each set of two parallel straight line sections is arranged so that they are orthogonal to each other, and four curved lines that connect the straight line sections of different sets, circles that are tangent to the ends of the curved lines are set. The center positions of each circle are Pc1 to Pc4, and the positions (contact points) where the circle and the wire cross-section are tangent to each other are P1 to P8. For example, the tangent points of the circle with the center position Pc1 are positions P1 and P2. The coordinates of the center position Pc1 are (Xc1, Yc1). The coordinates of the tangent point P1 are (X1, Y2). The diameter of this circle (hereinafter simply referred to as "circle diameter") can be expressed by the length of the major axis and the length of the minor axis, and is (Rx1, Ry1) here. The angle between the X direction and the major axis is θ1, and this angle θ1 is the direction of the circle. Similarly, the coordinates, diameter, and direction of the circle are set for the circles at center positions Pc2 to Pc4. The cross-sectional shape of the wire can be expressed by setting these parameters. The cross-section of the wire at the turn (position) can be set by setting these parameters for each turn.

[0023] For example, when the wire cross section is a circle and the diameter D1 is set to 4 (see FIG. 7), the parameters are expressed as follows: Center position: Pc1~Pc4=(0,0) Circle direction: θ1~θ4=0° Circle diameter:(Rx1,Ry1)~(Rx4,Ry4)=(2,2) Contact point: (X1, Y1) = (X8, Y8) = (2, 0) (X2,Y2)=(X3,Y3)=(0,-2) (X4,Y4)=(X5,Y5)=(-2,0) (X6,Y6)=(X7,Y7)=(0,2)

[0024] Furthermore, when the cross section of the wire has a shape with a part of a circle cut out, like the end winding portion formed at the end of the wire, and the diameter D1 of the imaginary circle formed along the outer edge is set to 4, and the radial length D2 of the cross section is set to 1 (see Figure 8), the parameters are expressed as follows: Center position: (Xc1,Yc1)=(√2,1) (Xc2,Yc2)=(-√2,1) (Xc3,Yc3)=(Xc4,Yc4)=(0,0) Circle direction: θ1~θ4=0° Circle diameter:(Rx1,Ry1)=(Rx2,Ry2)=(0,0) (Rx3, Ry3) = (Rx4, Ry4) = (2, 2) Contact points: (X1,Y1)=(X2,Y2)=(X8,Y8)=(√2,1) (X3,Y3)=(X4,Y4)=(X5,Y5)=(-√2,1) (X6,Y6)=(X7,Y7)=(0,2)

[0025] In addition to the above-mentioned shapes, the cross-sectional shape of the wire can be expressed using the above parameters even if it is an ellipse, an oval, a rectangle, or other shape. Examples of other shapes include a shape having an outer edge made up of two sets (four) of straight line sections, each set of two straight line sections that are non-parallel and facing each other and facing in different directions, and four curved sections connecting the straight line sections of different sets, and a shape made up of multiple curved sections that extend with different radii of curvature.

[0026] Returning to Fig. 1, the determination unit 14 determines for each design proposal whether the characteristics calculated by the calculation unit 13 satisfy the preset constraint conditions. Here, the constraint conditions are conditions set based on the characteristics of the coil spring, such as the physical properties of the coil spring, such as the load characteristics, and the shape conditions. For example, the maximum stress during compression and the upper and lower limits of the load are set as the constraint conditions.

[0027] The selection unit 15 selects an optimal design plan whose characteristics satisfy the objective function from among the design plans determined by the determination unit 14 to satisfy the constraints. In this case, there may be one or more optimal design plans. The objective function corresponds to a design goal, and conditions required for the coil spring and its design are set. For example, a condition for selecting from the design plans, such as the minimum mass of the coil spring, is set as the objective function.

[0028] The output unit 16 displays images and outputs sounds and lights under the control of the control unit 18. The output unit 16 is configured using a display (for example, the display 10a shown in FIG. 5), a speaker, a light source, and the like.

[0029] The storage unit 17 stores programs (for example, a design program for selecting a design plan, which will be described later) that the control unit 18 uses to execute various operations. The storage unit 17 also has a model information storage unit 171 that stores programs and parameters for creating an analysis model, and a design variable storage unit 172 that stores design variables. The design variable storage unit 172 stores various design variables associated with the design plans. The storage unit 17 is configured using a volatile memory or a nonvolatile memory, or a combination of these. For example, the storage unit 17 is configured using a RAM (Random Access Memory), a ROM (Read Only Memory), etc.

[0030] The control unit 18 controls the operation processing of each component part of the design device 1. For example, when an instruction to start the selection processing of a design plan is input via the input unit 11, the control unit 18 causes each unit to execute the process of determining the design plan. In addition, the control unit 18 causes the output unit 16 to output the selection result of the design plan selected by the selection unit 15.

[0031] The analysis model creation unit 12, calculation unit 13, judgment unit 14, selection unit 15, and control unit 18 are each configured using a processor such as a CPU (Central Processing Unit) or various arithmetic circuits that perform specific functions, such as an ASIC (Application Specific Integrated Circuit).

[0032] Next, the design proposal selection process will be described with reference to FIG. 9. FIG. 9 is a flowchart for explaining an outline of a method for selecting an optimum design proposal performed by a design device according to an embodiment of the present invention. For example, when an instruction to start the design proposal selection process is input via the input unit 11, the control unit 18 causes each unit to execute the design proposal determination process. Each design proposal is assigned a different number n (1 to n MAX :n MAX The explanation will be given assuming that the design proposals are marked with a number (e.g., "1" corresponds to the total number of design proposals).

[0033] First, the control unit 18 sets constraint conditions (step S101). The control unit 18 sets conditions input via the input unit 11 or conditions set in advance as constraint conditions. The constraint conditions are conditions set based on the characteristics of the coil spring, and include physical property values ​​of the coil spring, shape conditions, etc. The control unit 18 sets, for example, the maximum stress during compression and the upper and lower limit values ​​of the load as constraint conditions.

[0034] Thereafter, the control unit 18 sets an objective function (step S102). The control unit 18 sets the information input via the input unit 11 or a preset function as the objective function. The control unit 18 sets, for example, the minimum mass of the coil spring as the objective function. The setting of the constraint conditions and the setting of the objective function may be performed either first or simultaneously.

[0035] After the constraints and the objective function are set, the analytical model creation unit 12 creates an analytical model (step S103). The analytical model creation unit 12 may create an analytical model by reading a preset model creation program, or may create an analytical model by reading a model creation program associated with the constraints and the objective function, or may create an analytical model by reading a model creation program specified via the input unit 11.

[0036] After creating the analysis model, the control unit 18 sets the number n of the design plan to n=1 (step S104).

[0037] Thereafter, the calculation unit 13 calculates the value of the n-th design proposal. Setting The design variables are input into the analysis model to calculate the characteristics of the design proposal (step S105).

[0038] The determination unit 14 determines whether the characteristics calculated in step S106 satisfy the constraint conditions (step S106). If the determination unit 14 determines that the constraint conditions are satisfied (step S106: Yes), the control unit 18 proceeds to step S107. On the other hand, if the determination unit 14 determines that the constraint conditions are not satisfied (step S106: No), the control unit 18 proceeds to step S108.

[0039] In step S107, the control unit 18 sets the design plan to be judged as a candidate design plan. After setting, the control unit 18 proceeds to step S109.

[0040] In step S108, the control unit 18 sets the design plan to be judged as a non-design plan candidate. After setting, the control unit 18 proceeds to step S109.

[0041] In step S109, the control unit 18 determines whether n is n MAX The control unit 18 determines whether n is greater than n MAX If it is determined that n is equal to or greater than n (step S109: Yes), the process proceeds to step S111. MAX If it is determined that the value is smaller than (step S109: No), the process proceeds to step S110.

[0042] In step S110, the control unit 18 increments n by 1. After the increment, the control unit 18 proceeds to step S105 and repeats the above-described process for the incremented n-th number.

[0043] In step S111, the selection unit 15 selects an optimal design plan that satisfies the objective function from among the design plans set as the design plan candidates. Specifically, the selection unit 15 selects one or more design plans that minimize mass from among the design plans, and the selected design plans become the optimal design plans. At this time, the calculation unit 13 performs calculation processing based on the objective function. If the objective function uses mass, the calculation unit 13 calculates the mass for each design plan candidate using an analytical model.

[0044] After selecting the design proposal, the control unit 18 outputs the selected design proposal as an optimal design proposal (step S112). At this time, the control unit 18 may cause the output unit 16 to display the selection result, or may cause the storage unit 17 to store the optimal design proposal in association with the constraints and the objective function.

[0045] In the embodiment of the present invention described above, parameters that represent the wire cross section are set, and the wire cross section and a plurality of parameters including the pitch are calculated. Setting Using multiple design proposals consisting of total variables and an analysis model, a design proposal that satisfies the constraints and objective function that are the design conditions is selected as the optimal design proposal. According to this embodiment, it is possible to design a coil spring that meets requirements regardless of the cross section or pitch of the wire. Furthermore, it is possible to estimate the characteristics during actual use through analysis, which can assist in creating accurate design proposals.

[0046] Furthermore, according to the embodiment of the present invention, a design plan can be selected simply by setting constraint conditions and an objective function, thereby reducing the time required for design.

[0047] Furthermore, according to the embodiment of the present invention, by selecting design proposals using a single and common algorithm (the same program), the same design proposal can be obtained regardless of the user.

[0048] Furthermore, according to the embodiment of the present invention, the shape parameters and characteristic values ​​are Setting By managing these variables uniformly, it is possible to understand the relationship between shape and characteristic values.

[0049] In addition, the program to be executed by the design device according to this embodiment is provided, for example, as file data in an installable or executable format, recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), a USB medium, or a flash memory.

[0050] Furthermore, the program executed by the design apparatus according to this embodiment may be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network.

[0051] The design apparatus according to this embodiment can also function as a server apparatus, and can be configured to transmit and receive information to and from an external terminal connected via a network.

[0052] Although the embodiments for carrying out the present invention have been described above, the present invention should not be limited to only the above-described embodiments.

[0053] In this way, the present invention can include various embodiments not described here, and various design changes can be made within the scope that does not deviate from the technical idea specified by the claims.

[0054] As described above, the design program, design device, and design method according to the present invention are suitable for designing a coil spring that meets requirements regardless of the cross section or pitch of the wire. [Explanation of symbols]

[0055] 1 Design equipment 11 Input section 12 Analysis Model Creation Department 13 Calculation section 14 Judgment section 15 Selection section 16 Output section 17 Memory section 18 Control Unit 100, 101, 102 Coil springs 110 Center line 120 Wire cross section 171 Model information storage unit 172 Design variable memory section

Claims

1. On the computer, Set constraints based on the characteristics of the coil spring, An objective function indicating a design goal of the coil spring is set, creating an analytical model for calculating the characteristics of the coil spring; calculating characteristics based on the analysis model for each design plan consisting of a plurality of design variables including parameters expressing a cross-sectional shape of a wire of the coil spring and a distance between wires; determining whether the characteristics of each design proposal satisfy the constraints; selecting a design plan that satisfies the objective function from among the design plans determined to satisfy the constraints; Let it be done, The parameters expressing the wire cross-sectional shape are set for the wire cross section using an orthogonal coordinate system with the center position of the wire cross section as the origin, The parameters that represent the wire cross-sectional shape include coordinates of a center position of a circle that is tangent to the outer edge of the wire cross-section set in the wire cross-section, a circle diameter that is the length of the major axis and the length of the minor axis of the circle, coordinates of a tangent point between the outer edge of the wire cross-section and the circle, and an orientation of the circle. A design program characterized by:

2. an analytical model creation unit that creates an analytical model for calculating the characteristics of the coil spring; a calculation unit that calculates characteristics based on the analysis model for each design plan consisting of a plurality of design variables including parameters that represent a cross-sectional shape of a wire of the coil spring and a distance between wires; a determination unit that determines whether or not the characteristics of each design plan satisfy constraints set based on the characteristics of the coil spring; a selection unit that selects a design plan that satisfies an objective function that indicates a design goal of the coil spring from among the design plans that are determined to satisfy the constraints; Equipped with The parameters expressing the wire cross-sectional shape are set for the wire cross section using an orthogonal coordinate system with the center position of the wire cross section as the origin, The parameters that represent the wire cross-sectional shape include coordinates of a center position of a circle that is tangent to the outer edge of the wire cross-section set in the wire cross-section, a circle diameter that is the length of the major axis and the length of the minor axis of the circle, coordinates of a tangent point between the outer edge of the wire cross-section and the circle, and an orientation of the circle. A design device characterized by:

3. The design device that selects the design proposal for the coil spring is setting constraints based on the characteristics of the coil spring; An objective function indicating a design goal of the coil spring is set, creating an analytical model for calculating the characteristics of the coil spring; calculating characteristics based on the analysis model for each design plan consisting of a plurality of design variables including parameters expressing a cross-sectional shape of a wire of the coil spring and a distance between wires; determining whether the characteristics of each design proposal satisfy the constraints; Selecting a design plan that satisfies the objective function from among the design plans determined to satisfy the constraints; The parameters expressing the wire cross-sectional shape are set for the wire cross section using an orthogonal coordinate system with the center position of the wire cross section as the origin, The parameters that represent the wire cross-sectional shape include coordinates of a center position of a circle that is tangent to the outer edge of the wire cross-section set in the wire cross-section, a circle diameter that is the length of the major axis and the length of the minor axis of the circle, coordinates of a tangent point between the outer edge of the wire cross-section and the circle, and an orientation of the circle. A design method characterized by:

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