Electromagnetic device including coil case

Abstract

To provide an electromagnetic device which prevents a coil case from shifting in a radial direction of a core body.SOLUTION: The invention prevents a coil case from being mispositioned in a radial direction of a core body. The core body (5) of an electromagnetic device (6) includes an outer peripheral iron core (20) and at least three iron cores (41 to 44). The electromagnetic device further includes coils (51 to 54) mounted to the iron cores; and coil cases (61 to 64). Fitting parts (70, 80) which allow the core body and the coil case to be fitted with each other are respectively formed in the core body and each of the coil case.SELECTED DRAWING: Figure 2C

Description

Technical Field

[0001] The present invention relates to electromagnetic devices provided with a coil case, such as reactors, transformers, etc.

Background Art

[0002] In recent years, electromagnetic devices have been developed that include a core body including an outer peripheral core and a plurality of cores arranged inside the outer peripheral core. Coils are wound around each of the plurality of cores. Further, a technique is known in which the coil is assembled to the electromagnetic device in a state of being housed in a coil case for the purpose of insulating between the core body and the coil. See, for example, Patent Document 1 and Patent Document 2.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when using a coil case, a situation may occur in which the coil case is misaligned in the radial direction of the core body. As a result, it may be difficult to accurately and easily assemble the electromagnetic device.

[0005] Therefore, an electromagnetic device in which the coil case is not misaligned in the radial direction of the core body is desired.

Means for Solving the Problems

[0006] According to a first aspect of the present disclosure, there is provided an electromagnetic device including a core body, the core body including an outer peripheral core composed of a plurality of outer peripheral core portions, and at least three cores coupled to the plurality of outer peripheral core portions, further including a coil mounted on the at least three cores, and a coil case at least partially covering each of the at least three cores to insulate from the coil, wherein fitting portions for fitting the core body and the coil case to each other are formed on the core body and the coil case, respectively.

Advantages of the Invention

[0007] In the first aspect, the coil case and the core body are fitted to each other by the fitting portion. Therefore, once fitted, the coil case is prevented from being displaced in the radial direction of the core body. For this reason, the electromagnetic device can be assembled accurately and easily.

[0008] The objects, features, and advantages of the present invention will become more apparent from the following description of the embodiments in connection with the accompanying drawings.

Brief Description of the Drawings

[0009]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 2C

Figure 2D

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 5

Figure 6

Figure 7

Figure 8A

Figure 8B

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Throughout the drawings, common reference numerals are assigned to corresponding components. In the following description, a three-phase reactor will be mainly described as an example of the electromagnetic device. However, the application of the present disclosure is not limited to the three-phase reactor, and is widely applicable to polyphase reactors that require a certain inductance in each phase, and is also applicable to transformers. Further, the reactor according to the present disclosure is not limited to being provided on the primary side and the secondary side of the inverter in industrial robots and machine tools, and can be applied to various devices.

[0011] FIG. 1A is a cross-sectional view of the core body included in the electromagnetic device based on the first embodiment. FIG. 1B is a perspective view of the electromagnetic device shown in FIG. 1A. As shown in FIGS. 1A and 1B, the core body 5 of the electromagnetic device 6 includes an outer peripheral core 20 and three core coils 31 to 33 disposed inside the outer peripheral core 20. In FIG. 1, the core coils 31 to 33 are disposed inside the substantially hexagonal outer peripheral core 20. These core coils 31 to 33 are arranged at equal intervals in the circumferential direction of the core body 5.

[0012] Note that the outer peripheral core 20 may have another rotationally symmetric shape, for example, a circular shape. Also, the number of core coils only needs to be a multiple of 3. In that case, the reactor as the electromagnetic device 6 can be used as a three-phase reactor.

[0013] As can be seen from the drawings, each of the core coils 31 to 33 includes cores 41 to 43 extending only in the radial direction of the outer peripheral core 20, and coils 51 to 53 mounted on the cores. Each of at least three coils 51 to 53 is housed in coil cases 61 to 63. The coil cases 61 to 63 are preferably formed of a non-magnetic material, for example, resin.

[0014] The outer peripheral core 20 is composed of a plurality of, for example, three outer peripheral core portions 24 to 26 divided in the circumferential direction. The outer peripheral core portions 24 to 26 are integrally formed with the cores 41 to 43, respectively. As can be seen from FIG. 3 described later, the outer peripheral core portions 24 to 26 and the cores 41 to 43 are formed by laminating a plurality of magnetic plates, for example, iron plates, carbon steel plates, electromagnetic steel plates, or are formed of a powder core. When the outer peripheral core 20 is composed of a plurality of outer peripheral core portions 24 to 26 in this way, even when the outer peripheral core 20 is large, such an outer peripheral core 20 can be easily manufactured. Note that the number of cores 41 to 43 and the number of outer peripheral core portions 24 to 26 do not necessarily have to match.

[0015] Furthermore, the radially inner ends of each of the cores 41 to 43 are located near the center of the outer peripheral core 20. In the drawings, the radially inner ends of each of the cores 41 to 43 converge toward the center of the outer peripheral core 20, and the tip angle thereof is about 120 degrees. The radially inner ends of the cores 41 to 43 are separated from each other via magnetically connectable gaps 101 to 103.

[0016] In other words, the radially inner end of the core 41 is separated from the radially inner ends of the two adjacent cores 42 and 43 via the gaps 101 and 103. The same applies to the other cores 42 and 43. Note that the dimensions of the gaps 101 to 103 are equal to each other.

[0017] As described above, in the configuration shown in FIG. 1A, since the central core located at the center of the core body 5 is not required, the core body 5 can be configured to be lightweight and simple. Further, since the three core coils 31 to 33 are surrounded by the outer peripheral core 20, the magnetic field generated from the coils 51 to 53 does not leak to the outside of the outer peripheral core 20. Also, since the gaps 101 to 103 can be provided at an arbitrary thickness at low cost, it is advantageous in design compared to the reactor of the conventional structure.

[0018] Furthermore, in the core body 5 of the present disclosure, the difference in the magnetic path length between phases is reduced as compared with the electromagnetic device of the conventional structure. For this reason, in the present disclosure, it is also possible to reduce the inductance imbalance caused by the difference in the magnetic path length.

[0019] As can be seen with reference to FIG. 1B, each of the coils 51 to 53 attached to the cores 41 to 43 is a rectangular wire coil formed by winding a rectangular wire at least once. Of course, the coils 51 to 53 (54) may be coils other than the rectangular wire coil.

[0020] FIG. 2A is a perspective view of the coil case as viewed from the inner side in the radial direction of the electromagnetic device, and FIG. 2B is a perspective view of the coil case as viewed from the outer side in the radial direction of the electromagnetic device. In these drawings and other drawings described later, only the coil case 61 is shown as a representative, but it is assumed that the other coil cases 62, 63, (64) have the same configuration. The coil case 61 has a housing 61b with an open upper surface and an inner surface in the radial direction, and a hollow protrusion 61c protruding radially inward from the end surface on the outer side in the radial direction of the housing 61b.

[0021] The space between the housing 61b and the hollow protrusion 61c is a coil accommodating portion 61a having a shape suitable for accommodating the coil 51. Also, as will be described later, the hollow portion of the hollow protrusion 61c has a shape suitable for receiving the core 41.

[0022] As shown in FIGS. 2A and 2B, a convex portion 70a as a first fitting portion 70 is formed on a part of the outer peripheral surface of the housing 61b facing the outer peripheral core portion 24. Similarly, a convex portion 80a as a second fitting portion 80 is formed on a part of the inner peripheral surface of the hollow protruding portion 61c facing the core 41. In FIGS. 2A and 2B, two convex portions 70a and two convex portions 80a are formed for one coil case 61.

[0023] As can be seen from the figures, these convex portions 70a have a semi-circular cross-section and extend parallel to the axial direction of the electromagnetic device 6. The length of the convex portion 70a formed on the outer peripheral surface of the housing 61b is approximately equal to the height of the corresponding coil 51, and the length of the convex portion 80a formed on the inner peripheral surface of the hollow protruding portion 61c is approximately equal to the height of the opening of the corresponding coil 51. Alternatively, the convex portions 70a and 80a may at least partially extend parallel to the axial direction of the electromagnetic device 6.

[0024] FIG. 2C is a partial top view of the electromagnetic device. As shown in FIG. 2C, a concave portion 70b as a first fitting portion 70 is formed on the outer peripheral core portion 24. The concave portion 70b fits into the convex portion 70a formed on the outer peripheral surface of the coil housing portion 61a. Similarly, a concave portion 80b as a second fitting portion 80 is formed on the core 41. The concave portion 80b fits into the convex portion 80a formed on the inner peripheral surface of the hollow protruding portion 61c.

[0025] As can be seen from FIG. 2C, the second fitting portion 80 is closer to the center of the core body 5 than the first fitting portion 70. In other words, the distance between the first fitting portion 70 and the center of the electromagnetic device 6 is different from the distance between the second fitting portion 80 and the center of the electromagnetic device 6.

[0026] Furthermore, FIG. 3 is a partial perspective view of the electromagnetic device. As shown in FIG. 3, the coil case 61 containing the coil 51 is moved toward the outer peripheral core portion 24. Thereby, the core 41 integrated with the outer peripheral core portion 24 is inserted into the hollow protruding portion 61c of the coil case 61.

[0027] Since the coil case 61 is made of resin, the inner peripheral surface and the outer peripheral surface of the coil case 61 are temporarily curved during insertion. Then, when the convex portions 70a and 80a are respectively fitted into the concave portions 70b and 80b, the inner peripheral surface and the outer peripheral surface of the coil case 61 return to their original states. That is, the first fitting portion 70 and the second fitting portion 80 are each configured to snap-engage. Thereby, the coil 51 can be attached to the iron core 41. After the other coils 52 and 53 are also housed in the corresponding coil cases 62 and 63, they are similarly attached to the iron cores 42 and 43 of the outer peripheral iron core portions 25 and 26, respectively. Thereafter, the outer peripheral iron core portions 24 to 26 are assembled to each other, whereby the electromagnetic device 6 shown in FIG. 1B is formed.

[0028] As described above, in the present disclosure, the coil cases 61 to 63 and the core body 5 are fitted to each other by the fitting portions 70 and 80. Therefore, once they are fitted, the coil cases 61 to 63 do not shift in the radial direction of the core body 5. For this reason, it is possible to accurately and easily assemble the electromagnetic device 6.

[0029] Also, as described with reference to FIG. 2C, when the distance between the first fitting portion 70 and the center of the electromagnetic device 6 is different from the distance between the second fitting portion 80 and the center of the electromagnetic device 6, it is possible to further prevent the coil cases 61 to 63 from shifting in the radial direction of the core body 5.

[0030] FIG. 2D is a partial top view of an electromagnetic device in the prior art. In FIG. 2D, the fitting portions 70 and 80 are not formed. For this reason, the coil case 61' of the prior art may shift in the radial direction. The present disclosure overcomes such a problem as described above.

[0031] In FIG. 2A and the like, the convex portion 70a is formed on the coil case 61, and the concave portion 70b is formed on the outer peripheral iron core portion 24. However, as shown in FIGS. 4A to 4C which are partial cross-sectional views of the electromagnetic device in the present disclosure, the concave portion 70b may be formed on the coil case 61 and the convex portion 70a may be formed on the outer peripheral iron core portion 24. The same applies to the second fitting portion 80.

[0032] Also, in FIG. 2A etc., the convex portion 70a has a semi-circular cross-section. However, the cross-section of the convex portion 70a is not limited to a semi-circle, and may be, for example, rectangular as shown in FIG. 4B or triangular as shown in FIG. 4C. Naturally, the concave portion 70b shall have a shape corresponding to the convex portion 70a.

[0033] FIG. 5 is another perspective view of a coil case similar to FIG. 2B. In FIG. 5, in addition to the convex portion 70a described above, an additional convex portion 70a' extending parallel to the convex portion 70a is indicated by a broken line on the outer peripheral surface of the housing 61b. Further, a convex portion 80a similar to that in FIG. 2B is indicated by a broken line, and an additional convex portion 80a' extending parallel to the convex portion 80a is indicated by a broken line on the inner peripheral surface of the hollow protruding portion 61c. Naturally, when the additional convex portion 70a' and / or the additional convex portion 80a' are formed, corresponding additional concave portions 70b' and / or additional concave portions 80b' may be formed on the outer peripheral core portion 24 and the core 41.

[0034] As can be inferred from FIG. 5, a configuration may be adopted in which only the convex portion 70a and the additional convex portion 70a' are formed on the housing 61b, whereby two first fitting portions 70 are provided on one side of the outer peripheral surface of the housing 61b. Similarly, a configuration may be adopted in which only the convex portion 80a and the additional convex portion 80a' are formed on the hollow protruding portion 61c, whereby two second fitting portions 80 are provided on one side of the inner peripheral surface of the hollow protruding portion 61c. Further, as can be inferred from FIG. 5, a configuration may be adopted in which only the convex portion 70a is formed on the housing 61a, whereby the core body 5 and the coil case 61 are engaged only by the first fitting portion 70. Similarly, although not shown in the drawings, a configuration may be adopted in which only the convex portion 80a is formed on the hollow protruding portion 61c, whereby the core body 5 and the coil case 61 are engaged only by the second fitting portion 80. In such a case, a concave portion corresponding to the convex portions 70a, 70a' described above or a convex portion corresponding to the concave portions 80a, 80a' described above shall be formed. Even in such a case, it can be understood that the same effects as described above are achieved.

[0035] Furthermore, FIG. 6 is a diagram showing the magnetic flux density distribution of the outer peripheral core portion in the present disclosure. For the purpose of simplicity, FIG. 6 shows the magnetic flux density distribution of only the outer peripheral core portion 24 when driving the electromagnetic device 6 as a reactor. It is assumed that the other outer peripheral core portions 25 and 26 also exhibit the same magnetic flux density distribution as the outer peripheral core portion 24.

[0036] In FIG. 6, at both end portions of the outer peripheral core portion 24 in the circumferential direction of the electromagnetic device 6, both end portions adjacent to the radially inner end portion of the core 41, and the radially inner end portion of the core 41 and in the vicinity thereof, the magnetic flux density is small (indicated by the region Z1). On the other hand, at the radially outer end portion of the core 41, that is, at the central portion on the inner circumferential side of the outer peripheral core portion 24 in the circumferential direction of the electromagnetic device 6 and in the vicinity thereof, the magnetic flux density is large (indicated by the region Z2).

[0037] If the fitting portions 70 and 80 are formed at locations where the magnetic flux density is large, the core body 5 may generate heat or be a cause of noise. In the present disclosure, the fitting portions 70 and 80 are formed at the above-described locations where the magnetic flux density is small. Therefore, even if the fitting portions 70 and 80 are formed, it is possible to suppress heat generation and noise generation of the core body 5.

[0038] FIG. 7 is a top view of the core body of the electromagnetic device in another embodiment. The core body 5 shown in FIG. 7 includes a substantially octagonal outer peripheral core 20 and four core coils 31 to 34 arranged inside the outer peripheral core 20 and similar to those described above. These core coils 31 to 34 are arranged at equal intervals in the circumferential direction of the core body 5. Also, the number of cores is preferably an even number of 4 or more, whereby the reactor as the electromagnetic device 6 can be used as a single-phase reactor.

[0039] As can be seen from the drawings, the outer peripheral core 20 is composed of four outer peripheral core portions 24 to 27 divided in the circumferential direction. Each of the core coils 31 to 34 includes cores 41 to 44 extending in the radial direction and coils 51 to 54 attached to the cores. And, the respective radially outer ends of the cores 41 to 44 are integrally formed with the respective ones of the outer peripheral core portions 21 to 24. Note that the number of the cores 41 to 44 and the number of the outer peripheral core portions 24 to 27 do not necessarily have to match.

[0040] Furthermore, the respective radially inner ends of the cores 41 to 44 are located near the center of the outer peripheral core 20. In FIG. 7, the respective radially inner ends of the cores 41 to 44 converge toward the center of the outer peripheral core 20, and the tip angle thereof is about 90 degrees. And, the radially inner ends of the cores 41 to 44 are separated from each other via magnetically connectable gaps 101 to 104.

[0041] Also in FIG. 7, each of at least three of the coils 51 to 54 is housed in coil cases 61 to 64 similar to those described above. And, first fitting portions 70 and second fitting portions 80 are formed in the coil cases 61 to 64 and the core body 5 in the same manner as described above. Therefore, the coil cases 61 to 64 and the core body 5 are fitted to each other by the fitting portions 70 and 80, and the coil cases 61 to 64 are prevented from being displaced in the radial direction of the core body 5. Accordingly, it can be understood that the same effects as those described above can be obtained.

[0042] Furthermore, FIGS. 8A and 8B are cross-sectional views of a core body included in an electromagnetic device based on another embodiment. In these drawings, a transformer is shown as an example of the electromagnetic device 6. Since FIGS. 8A and 8B are the same as FIGS. 1A and 7, respectively, description of the members already described will be omitted. In FIGS. 8A and 8B, the radially inner ends of the cores 41 to 43 (44) are in contact with the radially inner ends of the adjacent cores 41 to 43 (44). For this reason, the electromagnetic device 6 shown in FIGS. 8A and 8B does not include the gaps 101 to 103 (104).

[0043] Also in FIGS. 8A and 8B, the coil cases 61 to 63 (64) and the core body 5 are formed with the first fitting portion 70 and the second fitting portion 80 in the same manner as described above. For this reason, it can be understood that even when the electromagnetic device 6 is a transformer, the same effects as described above can be obtained.

[0044] Aspects of the present disclosure According to a first aspect, there is provided an electromagnetic device (6) comprising a core body (5), the core body including an outer peripheral core (20) composed of a plurality of outer peripheral core portions (24 to 27), at least three cores (41 to 44) coupled to the plurality of outer peripheral core portions, further including coils (51 to 54) mounted on the at least three cores, and coil cases (61 to 64) at least partially covering each of the at least three cores and insulating from the coils, and fitting portions (70, 80) for fitting the core body and the coil cases to each other are formed on the core body and the coil cases, respectively. According to a second aspect, in the first aspect, the fitting portion includes a recess formed to at least partially extend parallel to the axial direction of the core body and a protrusion fitting into the recess. According to a third aspect, in the first or second aspect, the fitting portion is formed at least on one of between the inner peripheral surface of the coil case and the core and between the outer peripheral surface of the coil case and the outer peripheral core. According to a fourth aspect, in the first or second aspect, the fitting portion includes a first fitting portion formed between the outer peripheral surface of the coil case and the core and a second fitting portion formed between the inner peripheral surface of the coil case and the outer peripheral core, and the distance between the first fitting portion and the center of the electromagnetic device is made different from the distance between the second fitting portion and the center of the electromagnetic device. According to a fifth aspect, in any one of the first to fourth aspects, the number of the at least three cores is a multiple of 3. According to the sixth aspect, in any one of the first to fourth aspects, the number of the at least three cores is an even number of 4 or more.

[0045] Effects of the aspect In the first aspect, the coil case and the core body are fitted to each other by the fitting portion. Therefore, once they are fitted, the coil case is prevented from being displaced in the radial direction of the core body. For this reason, the electromagnetic device can be assembled accurately and easily. In the second and third aspects, the above-described effects can be achieved with a simple configuration. In the fourth aspect, displacement of the coil case in the radial direction of the electromagnetic device can be suppressed. In the fifth aspect, the electromagnetic device can be used as a three-phase reactor. In the sixth aspect, the electromagnetic device can be used as a single-phase reactor.

[0046] As described above, the embodiments of the present invention have been described. It will be understood by those skilled in the art that various modifications and changes can be made without departing from the scope of the disclosure of the claims described below.

Explanation of reference numerals

[0047] 5 Core body 6 Electromagnetic device 20 Outer peripheral core 24 to 27 Outer peripheral core portion 31 to 34 Core coil 41 to 44 Core 51 to 54 Coil 61 to 64 Coil case 61a Coil accommodating portion 61b Housing 61c Hollow protruding portion 70 First fitting portion 80 Second fitting portion 70a, 80a Convex portion 70a’, 80a’ Additional convex portion 70b, 80b Concave portion 70b’, 80b’ Additional concave portion Gaps 101 to 104

Claims

1. In an electromagnetic device, comprising a core body, the core body includes an outer peripheral core composed of a plurality of outer peripheral core portions, and at least three cores coupled to the plurality of outer peripheral core portions, furthermore, a coil mounted on the at least three cores, and a coil case that at least partially covers each of the at least three cores and insulates from the coil, a fitting portion for fitting the core body and the coil case to each other is formed on each of the core body and the coil case, the fitting portion includes a recess formed to extend at least partially parallel to the axial direction of the core body and a protrusion that fits into the recess, one of the recess and the protrusion is formed at both end portions of the outer peripheral core portion in the circumferential direction of the electromagnetic device, which are adjacent to the radially inner end portions of the cores corresponding to the outer peripheral core, and the other of the recess and the protrusion is formed on the outer circumferential surface of the housing of the coil case, or one of the recess and the protrusion is formed in the vicinity of the radially inner end portion of the core, and the other of the recess and the protrusion is formed on the inner circumferential surface of the hollow protruding portion of the coil case that protrudes radially inward from the end surface of the housing located radially outside the electromagnetic device, electromagnetic device.

2. The fitting portion is formed on at least one of between the inner circumferential surface of the coil case and the core and between the outer circumferential surface of the coil case and the outer peripheral core, the electromagnetic device according to claim 1.

3. The fitting portion includes a first fitting portion formed between the outer circumferential surface of the coil case and the core and a second fitting portion formed between the inner circumferential surface of the coil case and the outer peripheral core, the distance between the first fitting portion and the center of the electromagnetic device is made different from the distance between the second fitting portion and the center of the electromagnetic device, the electromagnetic device according to claim 1.

4. The number of the at least three cores is a multiple of 3, the electromagnetic device according to any one of claims 1 to 3.

5. The number of the at least three cores is an even number of 4 or more, the electromagnetic device according to any one of claims 1 to 3.

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