Core design apparatus and core design method

Abstract

To determine whether details are present in a shape of a core.SOLUTION: A core design apparatus calculates a distance to other nodes for all nodes of a mesh obtained by dividing a core into a plurality of parts. The core design apparatus records, for each of all the nodes, information indicating other nodes present within a predetermined distance. The core design apparatus generates a shape of the core by arranging a space or a tangible object for each mesh. The core design apparatus classifies boundaries between the space and the tangible object into groups for each continuous edge. When nodes positioned on the boundary are defined as boundary nodes, the core design apparatus determines whether or not details are present on the basis of other boundary nodes present within a predetermined distance from the boundary nodes.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a core design device and a core design method. [Background technology]

[0002] When designing a core, topology optimization may be used to find an optimal solution for the core shape. Topology optimization allows for the search for an optimal solution for the core shape that satisfies constraints set by the user. For example, the core design device disclosed in Patent Document 1 analyzes the stresses that occur in the core due to the centrifugal force that the rotor receives as it rotates. Then, the device searches for an optimal solution based on these stresses. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-114099 Summary of the Invention [Problem to be solved by the invention]

[0004] When manufacturing a core, a steel plate is punched out using a die. If the designed core has small details, the punched holes may connect with each other when punching the steel plate using the die, or the holes may not be punched out at all. [Means for solving the problem]

[0005] A core design device that solves the above problem is a core design device that designs a core, and includes: a calculation unit that calculates the distance between all nodes of a mesh that divides the core into multiple sections and other nodes; a recording unit that records information indicating the other nodes that exist within a predetermined distance for all of the nodes; a shape generation unit that generates the shape of the core by arranging space or tangible objects for each of the meshes; a group classification unit that classifies the boundaries between the space and the tangible objects into groups based on consecutive sides; and a judgment unit that, when a node located on the boundary is defined as an on-boundary node, determines whether or not details exist based on other on-boundary nodes that exist within the predetermined distance from the on-boundary node.

[0006] If there are other boundary nodes within a predetermined distance from the boundary node, the area between these boundary nodes may be a small part. The determination unit determines whether or not a small part exists based on the other boundary nodes that exist within a predetermined distance from the boundary node. This makes it possible to determine whether or not a small part exists in the shape of the core.

[0007] In the core design device, the determination unit may determine that the detail exists when an on-boundary node that belongs to a different group from the on-boundary node exists within the predetermined distance from the on-boundary node.

[0008] With regard to the core design device, if there is a boundary node within the specified distance from the boundary node that belongs to the same group as the boundary node and whose shortest travel distance when moving along the boundary from the boundary node is greater than or equal to a threshold value, it may be determined that the detail exists.

[0009] The core design device may be provided with a memory unit that stores the information recorded by the recording unit, and the determination unit may determine whether or not the detail exists based on the information stored in the memory unit.

[0010] The core design device may further include an update unit that updates the shape of the core based on the determination result of the determination unit. A core design method that solves the above problem is a core design method that designs a core, in which a computer executes the following steps: calculates the distance between every node of a mesh that divides the core into multiple sections and other nodes; records, for every node, information indicating the other nodes that exist within a predetermined distance; generates the shape of the core by arranging spaces or tangible objects for each mesh; classifies the boundaries between the spaces and the tangible objects into groups based on consecutive sides; and, when a node located on the boundary is defined as an on-boundary node, determines whether or not a detail exists in the shape of the core based on other on-boundary nodes that exist within the predetermined distance from the on-boundary node. This makes it possible to determine whether or not a detail exists in the shape of the core. [Effects of the Invention]

[0011] According to the present invention, it is possible to determine whether or not there is detail in the shape of the core. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a core design device. [Figure 2] FIG. 2 is a diagram showing a part of the core. [Figure 3] FIG. 3 is a flowchart showing the distance calculation control. [Figure 4] FIG. 4 is a flowchart showing the detailed determination control. [Figure 5] FIG. 5 is a diagram showing the distance from one node to another. [Figure 6] FIG. 6 is a diagram showing a predetermined distance from a node. [Figure 7] FIG. 7 is a diagram showing the boundary between space and a tangible object. [Figure 8] FIG. 8 is a diagram for explaining the determination of whether or not a detail exists. [Figure 9] FIG. 9 shows the updated core shape. [Figure 10] FIG. 10 is a diagram for explaining the determination of whether or not a detail exists. [Figure 11]FIG. 11 is a diagram showing an example of the shape of the core. [Figure 12] FIG. 12 is a diagram showing a predetermined distance from one boundary node. [Figure 13] FIG. 13 is a diagram showing the shortest movement distance from one boundary node. DETAILED DESCRIPTION OF THE INVENTION

[0013] [First embodiment] A first embodiment of a core design device and a core design method will be described. 1, the core design device 10 is a computer including a processor 11 and a storage unit 12. The processor 11 is, for example, a processing circuit configured to execute various software processes. The processing circuit may include a dedicated hardware circuit (e.g., an ASIC) that processes at least a part of the software processes. In other words, the software processes may be executed by a processing circuitry that includes at least one of one or more software processing circuits and one or more dedicated hardware circuits.

[0014] The processor 11 is, for example, a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor unit (MPU), a field-programmable gate array (FPGA), or other computing device. The processor 11 executes a series of instructions included in a program in response to a signal provided thereto or in response to the establishment of a predetermined condition.

[0015] The storage unit 12 is, for example, a random access memory (RAM) or other volatile memory. The storage unit 12 is configured to temporarily store programs and data. The storage unit 12 may also include a non-volatile memory.

[0016] Core design device 10 designs a core. More specifically, a processor 11 executes a program stored in storage unit 12, thereby designing a core by core design device 10. The core is a rotor core provided in a motor.

[0017] An input device 21 may be connected to the core design device 10. The input device 21 is, for example, a keyboard and a mouse, and may include buttons, keys, switches, a touchpad, or a microphone.

[0018] A display device 22 may be connected to the core design device 10. The display device 22 may be, for example, a liquid crystal monitor or an organic EL (Electro Luminescence) monitor, or may be a touch screen having a touch panel that also serves as the input device 21.

[0019] The core design device 10 designs cores using topology optimization. Topology optimization techniques include the ON / OFF method. The ON / OFF method is a method in which ON or OFF is assigned to each mesh that divides the design domain into multiple sections. Then, in topology optimization, an optimal shape is searched for that satisfies predetermined conditions. In the ON / OFF method, the position and shape of the mesh are fixed. The conditions used in topology optimization can be input to the core design device 10, for example, by the input device 21.

[0020] As shown in Fig. 2, when designing the core 31, the design region is the entire core 31 or a portion of the core 31. Fig. 2 shows an enlarged portion of the core 31 as an example. When a portion of the core 31 is the design region, it is sufficient to perform design by topology optimization for one design region obtained by equally dividing the core 31. Because the equally divided design region has symmetry, it is possible to design the entire core 31 by designing a portion of the core 31 by topology optimization.

[0021] An ID is assigned to each of the meshes 32 obtained by dividing the core 31 into multiple meshes, and to the nodes 33 of the meshes 32. The multiple meshes 32 may have different shapes. By assigning a space or a tangible object to the ID of the mesh 32, it is possible to arrange a space or a tangible object in the mesh 32. In the ON / OFF method, for example, a tangible object is assigned to ON, and a space is assigned to OFF. Then, by selecting ON or OFF corresponding to each mesh 32, it is possible to arrange a space or a tangible object in the mesh 32. A tangible object is a tangible object that constitutes the core 31. An example of a tangible object is a steel plate. A space is a hole that penetrates a tangible object. An example of a space is a hole that penetrates a steel plate. A mesh 32 in which a tangible object is arranged is indicated by a dot, and a mesh 32 in which a space is arranged is indicated by a blank.

[0022] 1, the core design device 10 includes a calculation unit 13, a recording unit 14, a shape generation unit 15, a group classification unit 16, a determination unit 17, and an update unit 18. These are functional units that function when the processor 11 executes predetermined processes.

[0023] The core design control performed by the core design device 10 will be described. By performing the core design control, a computer functioning as the core design device 10 executes a core design method. The core design device 10 performs the core design control after dividing the core 31 into a plurality of meshes 32. The core design control includes distance calculation control and detail judgment control. For ease of explanation, the explanation will be given using an example in which the shape of the core 31, which is the design region, is assumed to be rectangular, and this core 31 is divided into a plurality of meshes 32.

[0024] <Distance calculation control> The distance calculation control performed by the core design device 10 will be described. As shown in FIG. 3, in step S1, the core design device 10 calculates the distance from all nodes 33 to other nodes 33 in a mesh 32 obtained by dividing a core 31 into multiple sections. For example, as shown in FIG. 5, when calculating the distance from node 33A, which is one of the nodes 33, to other nodes 33, the distances to all nodes 33 other than node 33A are calculated as the other nodes 33. In the example shown in FIG. 5, only some of the arrows indicating the distances from node 33A to the other nodes 33 are illustrated. Also, although FIG. 5 illustrates the distances from node 33A to the other nodes 33, the distances to the other nodes 33 are also calculated for nodes 33 other than node 33A. By performing the processing of step S1, the core design device 10 functions as a calculation unit 13.

[0025] Next, in step S2, the core design device 10 records, for each node 33, information indicating other nodes 33 that exist within a predetermined distance R. In the example shown in FIG. 6, information indicating other nodes 33 that exist within the predetermined distance R from node 33A is recorded. The core design device 10 simply records the IDs of other nodes 33 that exist within the predetermined distance R from node 33A in association with the ID of node 33A. The area within the predetermined distance R from node 33A is within the range of a circle that has node 33A as its center and the predetermined distance R as its radius. By performing the processing of step S2, the core design device 10 functions as the recording unit 14.

[0026] The predetermined distance R is a distance that is determined in advance. The predetermined distance R is the dimension of a detail specified by the designer of the core 31. A tangible object whose dimension in a direction perpendicular to the thickness direction of the core 31 is equal to or less than the predetermined distance R is considered a detail. Similarly, a space whose dimension in a direction perpendicular to the thickness direction of the core 31 is equal to or less than the predetermined distance R is considered a detail. The predetermined distance R is, for example, twice the thickness of the core 31. If the designed core 31 has a detail, when the steel plate is punched out with a die, the punched holes may connect to each other or the holes may not be punched out at all.

[0027] The core design device 10 stores, in the storage unit 12, the other nodes 33 that exist within a predetermined distance R for each node 33. That is, the core design device 10 stores, in association with the ID of every node 33, the IDs of the other nodes 33 that exist within the predetermined distance R from that node 33 in the storage unit 12. The core design device 10 stores, for example, the above-mentioned information in a non-volatile memory, thereby storing information indicating the other nodes 33 that exist within the predetermined distance R in the storage unit 12.

[0028] <Detailed Judgment Control> The detailed determination control performed by the core design device 10 will be described. As shown in FIG. 4, in step S11, the core design device 10 generates the shape of the core 31 by arranging spaces or tangible objects for each mesh 32. The arrangement of the spaces or tangible objects is performed using, for example, random numbers. As an example, assume that the core 31 is designed as shown in FIG. 7. By performing the processing of step S11, the core design device 10 functions as a shape generation unit 15.

[0029] As shown in FIGS. 4 and 7, in step S12, the core design device 10 classifies the boundary between space and a tangible object into groups for each consecutive edge 34, 35. The core design device 10 determines that, among the edges 34, 35 that make up the boundary, the edges 34, 35 that are separated from each other belong to different groups. In the example shown in FIG. 7, the two edges 34, 35 are classified into different groups. One of the two edges 34, 35 is designated as the first edge 34, and the other is designated as the second edge 35. The first edge 34 belongs to the first group. The second edge 35 belongs to the second group, which is a group different from the first group. By performing the processing of step S12, the core design device 10 functions as the group classification unit 16.

[0030] 4 and 8, in step S13, the core design device 10 determines whether or not a detail exists based on other on-boundary nodes 33B and 33C that exist within a predetermined distance R from the on-boundary nodes 33B and 33C. The on-boundary nodes 33B and 33C are nodes 33 located on the boundary. The on-boundary nodes 33B and 33C are also nodes 33 located on an edge.

[0031] For each of the boundary nodes 33B and 33C, the core design device 10 determines whether there are boundary nodes 33B and 33C belonging to a different group from the boundary nodes 33B and 33C within a predetermined distance R. The core design device 10 determines that a detail exists when boundary nodes 33B and 33C belonging to a different group from the boundary nodes 33B and 33C exist within the predetermined distance R from the boundary nodes 33B and 33C. In the example shown in FIG. 8, three of the boundary nodes 33B belonging to the first group are within the predetermined distance R of the boundary nodes 33C belonging to the second group. Similarly, three of the boundary nodes 33C belonging to the second group are within the predetermined distance R of the boundary nodes 33B belonging to the first group. In this case, the core design device 10 determines that the number of details is six. In the example shown in FIG. 8, details of a tangible object sandwiched between two spaces are detected. That is, thin-walled portions are detected.

[0032] The determination of whether or not a detail exists may be made based on information stored in the storage unit 12. The information stored in the storage unit 12 records the IDs of all nodes 33 associated with the IDs of the other nodes 33 that exist within a predetermined distance R from the node 33. The core design device 10 can grasp the IDs of the on-boundary nodes 33B and 33C and the IDs of the other on-boundary nodes 33B and 33C that are located within the predetermined distance R from the on-boundary nodes 33B and 33C. The core design device 10 may determine whether the on-boundary nodes 33B and 33C with these IDs belong to the same group. By performing the processing of step S13, the core design device 10 functions as the determination unit 17.

[0033] As shown in Figures 4 and 9, in step S14, the core design device 10 updates the shape of the core 31. More specifically, the core design device 10 rearranges space or tangible objects in the mesh 32. The core design device 10 rearranges space or tangible objects in the mesh 32, for example, according to a genetic algorithm, which is one of the evolutionary algorithms. For example, the shape of the core 31 as shown in Figure 9 is obtained by updating. By performing the processing of step S14, the core design device 10 functions as an update unit 18.

[0034] Upon completing the process of step S14, the core design device 10 returns to step S12. As a result, in steps S12 and S13, it is determined whether or not details exist in the shape of the core 31 obtained by rearranging space or tangible objects in the mesh 32. For example, in the example shown in Fig. 10, in the shape of the core 31 obtained by updating, there are no on-boundary nodes 33B and 33C that belong to a different group from the on-boundary nodes 33B and 33C within the predetermined distance R from the on-boundary nodes 33B and 33C. Therefore, it is determined that there are no details in the shape of the core 31 obtained by updating.

[0035] If the optimal shape is obtained within the constraint conditions, the core design device 10 ends the detail judgment control. For example, after step S13, it is determined whether the optimal shape is obtained, and if the optimal shape is obtained, the detail judgment control ends, and if the optimal shape is not obtained, the process proceeds to step S14. One of the constraint conditions is the absence of details. The optimal shape is determined, for example, by magnetic conditions, stress conditions, etc.

[0036] When an optimal shape is obtained, the core design device 10 outputs the optimal shape. For example, the core design device 10 outputs the optimal shape to the display device 22, thereby providing the optimal shape to the designer.

[0037] [Effects of the first embodiment] According to the first embodiment, the following effects can be obtained. (1-1) If other on-boundary nodes 33B, 33C exist within a predetermined distance R from the on-boundary nodes 33B, 33C, the area between these on-boundary nodes 33B, 33C may be a small detail. The core design device 10 determines whether or not a small detail exists based on the other on-boundary nodes 33B, 33C that exist within the predetermined distance R from the on-boundary nodes 33B, 33C. This makes it possible to determine whether or not a small detail exists in the shape of the core 31.

[0038] (1-2) The core design device 10 determines that a detail exists when on-boundary nodes 33B and 33C that belong to a different group from the on-boundary nodes 33B and 33C exist within a predetermined distance R from the on-boundary nodes 33B and 33C. When on-boundary nodes 33B and 33C that belong to a different group from the on-boundary nodes 33B and 33C exist within a predetermined distance R from the on-boundary nodes 33B and 33C, the area between these on-boundary nodes 33B and 33C is a detail. Therefore, by performing the determination as described above, it is possible to determine whether a detail exists.

[0039] (1-3) The core design device 10 stores the information recorded by the recording unit 14 in the memory unit 12. If distance calculation control is performed each time a determination is made as to whether a detail exists, the amount of calculation required by the core design device 10 will be enormous. Because the shape and position of the mesh 32 are fixed, the distance between the nodes 33 is constant. Therefore, when determining whether a detail exists, the core design device 10 can use the information stored in the memory unit 12 to determine whether a detail exists. This reduces the amount of calculation required compared to when distance calculation control is performed each time a determination is made as to whether a detail exists. As a result, the time required for core design control can be shortened.

[0040] (1-4) Based on the result of the determination as to whether or not a detail exists, the core design device 10 updates the shape of the core 31. This makes it possible to obtain the shape of the core 31 without any detail. [Second embodiment] A second embodiment of a core design device and a core design method will be described. In the second embodiment, the process performed in step S13 differs from that in the first embodiment. The differences from the first embodiment will be described.

[0041] An example will be described in which the shape of the core 31 is designed in step S11 as shown in Fig. 11. In the example shown in Fig. 11, when the boundary between space and a tangible object is classified into groups for each continuous edge 36, one group is obtained. Therefore, in the example shown in Fig. 11, all boundary nodes 33D belong to the same group.

[0042] In step S13, the core design device 10 determines that a detail exists if there is a boundary node 33D within a predetermined distance R from the boundary node 33D that belongs to the same group as the boundary node 33D and whose shortest movement distance along the boundary from the boundary node 33D is equal to or greater than a threshold. The threshold is set based on the predetermined distance R and the size of the mesh 32. The threshold is set so that it can be determined whether a detail exists from the boundary node 33D that belongs to the same group. As an example, the threshold is set to 3.

[0043] As shown in Figure 12, the following description focuses on boundary node 33E, which is one of boundary nodes 33D. Five boundary nodes 33F, 33G, 33H, 33I, and 33J, which belong to the same group, are located within a predetermined distance R from boundary node 33E. Core design device 10 calculates the shortest travel distance when moving along the boundary from boundary node 33E to each of boundary nodes 33F, 33G, 33H, 33I, and 33J. The shortest travel distance is the number of sides from boundary node 33E to each of boundary nodes 33F, 33G, 33H, 33I, and 33J.

[0044] As shown in Fig. 13, the shortest movement distance from the on-boundary node 33E to the on-boundary node 33J is 8. Therefore, the core design device 10 determines that a detail exists. In the example shown in Fig. 13, a spatial detail is detected. As an example, the description has been given focusing on one on-boundary node 33E, but a similar determination is made for all on-boundary nodes 33D.

[0045] [Effects of the second embodiment] According to the second embodiment, in addition to the effects (1-1), (1-3) and (1-4) of the first embodiment, the following effects can be obtained.

[0046] (2-1) The core design device 10 determines that a detail exists when there is an on-boundary node 33D within a predetermined distance R from the on-boundary node 33D that belongs to the same group as the on-boundary node 33D and whose shortest movement distance when moved along the boundary from the on-boundary node 33D is equal to or greater than a threshold. This makes it possible to determine whether a detail exists even when the on-boundary node 33D belongs to the same group.

[0047] [Example of change] Each embodiment can be modified as follows: The embodiments and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0048] The first embodiment and the second embodiment may be combined. For example, the core design device 10 may determine whether or not a detail exists by using boundary nodes belonging to different groups through the processing of the first embodiment, and then determine whether or not a detail exists by using boundary nodes belonging to the same group through the processing of the second embodiment.

[0049] In each embodiment, the core design device 10 may output the determination result of step S13. This allows the designer to recognize whether or not there is a detail in the shape of the core 31. In this case, the core design device 10 does not need to perform the process of step S14.

[0050] In each embodiment, the core design device 10 may perform distance calculation control each time it determines whether or not a detail exists. In each embodiment, the design of a rotor core of a motor has been described as an example. However, the core to be designed is not limited to the rotor of a motor. For example, the design target may be a stator core of a motor. In addition, the design target may be a rotor / stator core of a generator, which is a rotating electrical machine other than a motor, or a core of a transformer or inductor. [Explanation of symbols]

[0051] 10...core design device, 12...memory unit, 13...calculation unit, 14...recording unit, 15...shape generation unit, 16...group classification unit, 17...determination unit, 18...update unit, 31...core, 32...mesh, 33...node, 33B, 33C, 33D, 33E, 33F, 33G, 33H, 33I, 33J...boundary nodes, 34, 35, 36...edges.

Claims

1. A core design device for designing a core, comprising: a calculation unit that calculates the distance between each node of a mesh obtained by dividing the core into a plurality of nodes and other nodes; a recording unit that records information indicating the other nodes that exist within a predetermined distance for each of the nodes; a shape generation unit that generates a shape of the core by arranging a space or a tangible object for each of the meshes; a group classification unit that classifies the boundary between the space and the tangible object into groups for each continuous side; A core design device comprising: a judgment unit that, when a node located on the boundary is defined as an on-boundary node, determines whether or not a detail exists based on other on-boundary nodes that exist within the specified distance from the on-boundary node.

2. 2. The core design device according to claim 1, wherein the determination unit determines that the detail exists when there is an on-boundary node within the predetermined distance from the on-boundary node that belongs to a different group from the on-boundary node.

3. 2. The core design device according to claim 1, wherein the determination unit determines that the detail exists if there is a boundary node within the specified distance from the boundary node that belongs to the same group as the boundary node and whose shortest movement distance when moving along the boundary from the boundary node is greater than or equal to a threshold value.

4. a storage unit for storing the information recorded by the recording unit, The core design device according to claim 1 , wherein the determining unit determines whether or not the detail exists based on the information stored in the storage unit.

5. The core design device according to claim 1 , further comprising an update unit that updates the shape of the core based on a determination result from the determination unit.

6. A core design method for designing a core, comprising: The computer Calculating the distance between all nodes of a mesh obtained by dividing the core into a plurality of nodes and other nodes; recording information indicating the other nodes that exist within a predetermined distance for each of the nodes; generating a shape of the core by arranging a space or a tangible object for each of the meshes; classifying the boundary between the space and the tangible object into groups for each continuous side; A core design method that, when a node located on the boundary is defined as an on-boundary node, determines whether or not a detail exists based on other on-boundary nodes that exist within the specified distance from the on-boundary node.

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