Iron cores for electromagnetic devices

Abstract

To provide an iron core of electromagnetic equipment that enables operation while measuring iron loss characteristics in a manufacturing process because compressive stress applied during assembly causes an increase in iron loss in an iron core using a soft magnetic thin plate.SOLUTION: An iron core of electromagnetic equipment composed of laminated soft magnetic thin plates includes a terminal for resistance measurement consisting of a conductive thin plate placed so as to be in contact with a soft magnetic thin plate and partially exposed to the outside, and the terminal for resistance measurement has a disconnection line.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to iron loss measurement of electromagnetic devices, and more particularly to an iron core structure of an electromagnetic device that allows iron loss to be measured during the manufacturing process. [Background technology]

[0002] Soft magnetic thin plates, mainly silicon steel sheets and amorphous materials, are widely used for the iron cores of electromagnetic devices such as transformers and electric motors. Recently, electromagnetic devices have become smaller and operate at higher frequencies, which has led to stricter requirements for the iron loss characteristics of these iron cores. In general, when constructing an iron core using soft magnetic thin plates, a structure in which thin plates are laminated is used to reduce eddy current loss, but when compressive stress is applied to the iron core, iron loss increases. Therefore, conventionally, measures have been taken to test the iron loss characteristics of iron cores using soft magnetic thin plates by actually exciting the iron core before shipping.

[0003] Background art in this technical field includes Patent Document 1. Patent Document 1 discloses a method for inspecting iron loss characteristics by measuring the interlaminar resistance between the outermost thin plates of an iron core. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-256064 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, in the actual manufacturing process, the resistance value cannot be measured if the outermost layer of the iron core is covered with insulating materials such as insulating paper or insulating coating. In particular, silicon steel sheets are used with insulating coatings to maintain insulation, and amorphous materials are thin and prone to breaking, so the entire iron core is often protected with insulating paper.

[0006] Furthermore, in cores using soft magnetic thin plates, the compressive stress applied during assembly of the core and windings causes an increase in iron loss. When actually exciting the core to measure the iron loss characteristics after product assembly, if a significant deterioration in the iron loss characteristics is confirmed during the measurement, it becomes necessary to remake the core or disassemble the product and then reassemble it, which requires a lot of work time and personnel costs. Therefore, there is a need for a measurement method that allows work to be done while measuring the iron loss characteristics during the manufacturing process.

[0007] In contrast, the iron loss measurement method of Patent Document 1 is merely a method for verifying variations in iron loss characteristics during iron core production, and does not take into consideration measuring iron loss during work in the actual manufacturing process.

[0008] In view of the above-mentioned problems, an object of the present invention is to provide an iron core for an electromagnetic device that allows iron loss to be measured during the manufacturing process. [Means for solving the problem]

[0009] One example of the present invention is an iron core of an electromagnetic device constructed by laminating soft magnetic thin plates, and is equipped with a resistance measurement terminal made of a conductive thin plate that is sandwiched so as to come into contact with the soft magnetic thin plates and is arranged so that a portion of the conductive thin plate is exposed to the outside, and the resistance measurement terminal has a disconnect wire. Effect of the Invention

[0010] According to the present invention, it is possible to provide an iron core for an electromagnetic device, the iron loss of which can be measured during the manufacturing process. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic external view of a wound core for a stationary induction motor in a first embodiment. FIG. [Diagram 2] FIG. 2 is a diagram showing a resistance measurement terminal having a dotted separation line in Example 1. [Diagram 3] FIG. 4 is a diagram showing a resistance measurement terminal having a groove-shaped separation line in Example 1. [Figure 4] 4 is a diagram showing lamination surfaces of a portion of the iron core in which a contact terminal is sandwiched in the iron core in the first embodiment. FIG. [Diagram 5] 4 is a diagram illustrating a method of winding an insulating material around an iron core after the resistance measuring terminals have been cut off in Example 1. FIG. [Figure 6] FIG. 4 is a diagram for explaining a method for measuring an interlaminar resistance value in Example 1. [Figure 7] FIG. 11 is a schematic external view of a stacked core for a stationary induction motor in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. EXAMPLES

[0013] Fig. 1 is a schematic external view of a wound core for a stationary induction machine in this embodiment. In Fig. 1, the core 1 is a wound core made of laminated soft magnetic thin plates, and is equipped with two resistance measurement terminals 2a, 2b. An insulating material 3 such as insulating paper is wound around the outermost layer of the core 1, and the resistance measurement terminals 2a, 2b are sandwiched so as to come into contact with the soft magnetic thin plates, and are configured so as to be partially exposed to the outside of the core 1. A winding 4 is also wound around the core 1.

[0014] Fig. 2 is a diagram showing the configuration of the resistance measuring terminal in this embodiment. Fig. 2 shows only the resistance measuring terminal 2a, but the resistance measuring terminal 2b is omitted since it has the same configuration as 2a. In Fig. 2(A), the resistance measuring terminal 2a will be described with the portion in contact with the soft magnetic thin plate as a contact terminal 6a, but the resistance measuring terminal 2a and the contact terminal 6a are cut out from the same material, are integrated, and are made of a conductive material.

[0015] Since contact terminal 6a is sandwiched inside iron core 1 and is subjected to the same magnetic field as the soft magnetic sheet, it is desirable to use a material for contact terminal 6a that has a magnetic permeability close to that of the soft magnetic sheet, or the same material, in order to avoid non-uniformity in the magnetic field. Also, in order to correctly measure the interlayer resistance of the iron core, it is desirable to use a material with high conductivity, or the same material as the iron core, for contact terminal 6a and resistance measurement terminal 2a.

[0016] A dotted separation line 5 is provided between the resistance measurement terminal 2a and the contact terminal 6a, and the part of the resistance measurement terminal 2a exposed outside the iron core 1 can be separated from the contact terminal 6a by cutting along the separation line 5 with scissors or by applying a bending or pulling force.

[0017] There are no particular limitations on the length L1 of the resistance measurement terminal 2a in the direction parallel to the separation line 5 and the length L2 of the contact terminal 6a, but the length L1 must be wide enough to allow connection of the measurement terminal of a resistance measuring instrument, and it is preferable that the length L2 of the contact terminal 6a is as long as possible, since this increases the contact area with the soft magnetic thin plate that constitutes the iron core 1 and reduces the effect of the contact resistance between the contact terminal 6a and the soft magnetic thin plate on the interlayer resistance value to be measured. Furthermore, if the length L1 of the resistance measurement terminal 2a and the length L2 of the contact terminal 6a are made equal, the effort required for processing the resistance measurement terminal, such as cutting it out, can be reduced.

[0018] Fig. 2(B) is a cross-sectional view of line A-A' in Fig. 2(A). The dotted separation line 5 is formed by continuously arranging holes penetrating the resistance measurement terminal 2a in the thickness direction. Here, if the spacing between the holes of the separation line 5 is narrowed or the area of ​​the holes is enlarged, the resistance measurement terminal 2a becomes easier to separate.

[0019] Fig. 3 is a diagram showing another configuration of the resistance measurement terminal in this embodiment. In Fig. 3, the same components as in Fig. 2 are given the same reference numerals and their explanation will be omitted. In Fig. 3, the difference from Fig. 2 is that the separation line 7 between the resistance measurement terminal 2a and the contact terminal 6a is configured in a groove shape.

[0020] Fig. 3(A) shows an example in which the separation line 7 between the resistance measurement terminal 2a and the contact terminal 6a is configured in a groove shape, and Fig. 3(B) is a cross-sectional view of line B-B' in Fig. 3(A). By deepening the groove of the separation line 7 or widening the groove, it becomes easier to separate the exposed part of the resistance measurement terminal 2a from the iron core 1.

[0021] Fig. 4 is a diagram showing the lamination surface of the portion where the contact terminals 6a, 6b are sandwiched in the iron core 1. As shown in Fig. 4, the iron core 1 is configured by sandwiching the contact terminals 6a, 6b in the same lamination direction as the soft magnetic thin plates constituting the iron core 1, and further by laminating so that the contact terminals 6a, 6b are in contact with at least one surface of the soft magnetic thin plate inside the outermost insulating material 3 in the lamination direction.

[0022] The insertion positions of the contact terminals 6a, 6b of the resistance measurement terminals 2a, 2b are preferably on both outermost layers in the lamination direction of the iron core, positions where the resistance value between the resistance measurement terminals 2a, 2b is largest and where changes in the resistance value can be easily observed.

[0023] In the resistance measurement terminals 2a, 2b, the separation wires connecting to the contact terminals 6a, 6b, respectively, are exposed to the outside of the iron core 1, and once it is no longer necessary to measure the interlayer resistance, for example after the assembly of the iron core and the windings is completed, the parts of the resistance measurement terminals 2a, 2b exposed to the outside of the iron core 1 can be separated from the separation wires. The timing of separating the resistance measurement terminals during the manufacturing process is arbitrary.

[0024] FIG. 5 is a diagram for explaining a method of winding an insulating material around the iron core 1 after the resistance measurement terminals 2a, 2b in this embodiment are cut off. As shown in FIG. 5(A), the resistance measurement terminals 2a, 2b are configured to be exposed to the outside of the iron core 1, and after the resistance measurement terminals 2a, 2b are cut off, the insulating material 3 is not wound on the cut cross section of the contact terminals 6a, 6b, and the cut section is exposed to the outside of the iron core 1. Therefore, as shown in FIG. 5(B), an insulating material 8 for protecting the exposed part is used, which has a sufficient area to cover the exposed part of the iron core 1 where the insulating material 3 is not wound, and the exposed part is wound so as to be covered with the insulating material 8, as shown in FIG. 5(C). This allows the iron core 1 to be handled in the same way as a general iron core that does not have a resistance measurement terminal.

[0025] Fig. 6 is a diagram for explaining a method for measuring the interlayer resistance in this embodiment. As shown in Fig. 6, by connecting the terminals of a resistance measuring device 9, such as a resistance meter, a multimeter, or an LCR meter, to the resistance measuring terminals 2a and 2b exposed from the iron core 1, it is possible to perform work in the manufacturing process while measuring the interlayer resistance successively. By obtaining the relationship between the interlayer resistance and the iron loss in advance by a preliminary measurement, the iron loss can be measured by the iron core structure of the electromagnetic device in this embodiment. Note that, assuming a case where the resistance is measured by a four-terminal method, for example, the number of resistance measuring terminals is not limited to two, and may be four or any other number.

[0026] Furthermore, according to this embodiment, the interlaminar resistance is measured by the resistance measuring terminals 2a and 2b before and after annealing the core, and the change in the interlaminar resistance is observed, so that seizure of the material that occurs during annealing can be detected. In an iron core constructed by laminating thin soft magnetic thin plates of amorphous material or the like, there is a possibility that the soft magnetic thin plates will be partially stuck together due to annealing. The resistance value of the stuck parts is significantly reduced, so that current flows more easily, leading to an increase in iron loss. Therefore, if the interlaminar resistance value after annealing is significantly reduced compared to before annealing, it can be determined that seizure has occurred, and it is possible to take measures such as finding the burned parts and removing the stuck parts.

[0027] As described above, according to this embodiment, it is possible to provide an iron core for an electromagnetic device that is provided with a resistance measuring terminal for measuring the interlaminar resistance that is sandwiched so as to come into contact with the soft magnetic thin plate inside the insulating material of the outermost layer of the iron core, and that makes it possible to easily inspect the iron loss characteristics of the iron core while measuring the interlaminar resistance value during the manufacturing process, even for an iron core whose outermost layer is an insulating material. In addition, the resistance measuring terminal has a separation line so that it can be separated from the iron core without generating any excess protrusions after the assembly of the iron core and the windings is completed and it has been confirmed that there are no problems with the iron loss characteristics. EXAMPLES

[0028] Fig. 7 is a schematic external view of a stacked core for a stationary induction machine in this embodiment. As shown in Fig. 7, the core 1 in this embodiment has two resistance measurement terminals 2a, 2b. The outermost layer in the lamination direction of the core 1 is sandwiched between insulating materials 3 such as silicon steel plates coated with an insulating film, and the resistance measurement terminals 2a, 2b are configured to be exposed to the outside of the core 1. Similarly to the first embodiment, the resistance measurement terminals 2a, 2b have contact terminals 6a, 6b that are sandwiched between soft magnetic thin plates used in the stacked core.

[0029] In general, the soft magnetic thin plates used in stacked cores are thicker and less likely to deform than the soft magnetic thin plates used in wound cores, so if the contact terminals 6a, 6b are thick, gaps will form in the lamination direction of the core 1 near the parts where the contact terminals 6a, 6b are sandwiched. When the core 1 is assembled, it is fastened in the lamination direction with bands or bolts, but if gaps form, they will be crushed by compression, applying bending stress to the soft magnetic thin plates and deteriorating the iron loss characteristics. For these reasons, it is desirable to use a thin material for the contact terminals 6a, 6b that are sandwiched between the core 1, as long as it does not impair workability.

[0030] As described above, according to this embodiment, it is possible to provide an iron core for an electromagnetic device that allows the iron loss characteristics of the iron core to be easily inspected while measuring the interlayer resistance during the manufacturing process, even for a stacked core. It is also possible to provide an iron core for an electromagnetic device that has a resistance measurement terminal that can be separated from the main body so that no extra protrusions are left after the core and windings are assembled.

[0031] Although the embodiments have been described above, the present invention is not limited to the above-mentioned embodiments, and various modified examples are included. For example, the above-mentioned embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0032] 1: iron core, 2a, 2b: resistance measurement terminal, 3: insulating material, 4: winding, 5: separation wire, 6a, 6b: contact terminal, 7: separation wire, 8: insulating material, 9: resistance measurement device

Claims

1. An iron core for an electromagnetic device constructed by laminating soft magnetic thin plates, a resistance measuring terminal made of a conductive thin plate that is sandwiched in contact with the soft magnetic thin plate and is arranged so that a part of the conductive thin plate is exposed to the outside; 13. An iron core for an electromagnetic device, wherein the resistance measuring terminal has a disconnection wire.

2. 2. The iron core of claim 1, An iron core of an electromagnetic device, characterized in that the separation wire is configured so as to separate the portion of the resistance measurement terminal exposed outside the iron core from the contact portion sandwiched between the soft magnetic thin plates.

3. 2. The iron core of claim 1, The iron core has an outermost layer wound with an insulating material, 2. An iron core for an electromagnetic device, wherein the resistance measuring terminal is sandwiched so as to come into contact with the soft magnetic thin plate on the inner side of the insulating material.

4. 2. The iron core of claim 1, An iron core for an electromagnetic device, comprising two of the resistance measuring terminals.

5. 2. The iron core of claim 1, An iron core for an electromagnetic device, wherein the separation line is a dotted separation line formed by continuously arranging holes penetrating in the thickness direction.

6. 2. The iron core of claim 1, 13. An iron core for an electromagnetic device, wherein the separation line is a groove-shaped separation line.

7. 2. The iron core of claim 1, The resistance measuring terminal is a conductive thin plate cut out from the same material as the iron core. An iron core for an electromagnetic device characterized by:

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