Stationary induction apparatus and coil

Abstract

To provide a stationary induction apparatus and a coil that can be made smaller by suppressing winding swelling and achieving low loss.SOLUTION: An inner coil 4 of a stationary induction apparatus 1 according to an embodiment includes, when viewed from the axial direction, long-side flat portions 10 whose inner or outer peripheral sides are flat and which are arranged opposite each other with a leg portion 2c in between, short-side flat portions 11 which are arranged opposite each other with the leg portion 2c in between, and a plurality of corners 12 connecting the long-side flat portions 10 and the short-side flat portions 11. At least one corner 12 is formed in an irregular shape in which, when the direction along the long-side flat portion 10 is defined as the vertical direction and the direction along the short-side flat portion 11 is defined as the horizontal direction, the horizontal distance from the long-side flat portion 10 to the end of the short-side flat portion 11 differs from the vertical distance from the end of the long-side flat portion 10 to the short-side flat portion 11.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to a stationary inductive device, a coil. [Background technology]

[0002] A stationary induction device, as disclosed in Patent Document 1 for example, includes an iron core and a coil attached to the legs of the iron core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-332235 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of such a conventional configuration, there was a problem that it was difficult to miniaturize. For example, the coil of a stationary induction device is formed into a ring shape by winding a conductor, but the conductor needs to be thickened in order to increase the capacity. In that case, if the bending radius of the corners is made small, the conductor is wound without being tightly attached, resulting in a so-called bulged winding state. For this reason, in the past, the bending radius was made large to make the conductor tightly attached, which led to an increase in the outer size of the coil. Furthermore, the larger the coil, the longer the circumference, which led to an increase in loss.

[0005] Therefore, the present invention provides a stationary induction device and coil that can be made smaller by suppressing winding swelling and that can achieve low loss. [Means for solving the problem]

[0006] A stationary induction device according to an embodiment comprises an iron core, and a coil formed into an overall ring shape by winding a conductor and attached to the iron core, and when viewed from the axial direction along the iron core, the coil has long-side flat portions which are flat on the inner or outer peripheral side and arranged opposite each other across the leg, short-side flat portions which are arranged opposite each other across the leg, and a plurality of corners connecting the long-side flat portions and the short-side flat portions, and at least one corner is formed into an irregular shape in which, when the direction along the long-side flat portion is the vertical direction and the direction along the short-side flat portion is the horizontal direction, the horizontal distance from the long-side flat portion to the end of the short-side flat portion differs from the vertical distance from the end of the long-side flat portion to the short-side flat portion. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of a stationary induction device according to an embodiment; [Diagram 2] FIG. 2 is a diagram showing a schematic configuration example of an inner circumferential coil; [Diagram 3] FIG. 2 is a diagram showing a schematic configuration example of an outer circumferential coil; [Figure 4] Diagram explaining the difference between the inner coil and a conventional coil [Diagram 5] Diagram explaining the difference between the outer coil and a conventional molded coil [Figure 6] FIG. 2 is a diagram showing an example of the dimensions of the outer coil; [Figure 7] FIG. 13 is a schematic diagram showing another example of the configuration of the inner circumferential coil; [Figure 8] A diagram explaining the difference in arrangement from the conventional configuration. [Figure 9] FIG. 1 is a schematic diagram showing an example of a configuration in which a cushioning material is provided; [Figure 10] FIG. 13 is a schematic diagram showing another example of the configuration of the outer circumferential coil; [Figure 11] FIG. 1 is a diagram illustrating the arrangement of an inner coil and an outer coil. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described with reference to the drawings. As shown in a front view in Fig. 1, a stationary induction device 1 includes an iron core 2 and a coil 3 attached to the iron core 2. In this embodiment, a so-called molded transformer is assumed as the stationary induction device 1, but for the sake of simplicity, structures for supporting the iron core 2 and the coil 3 are omitted from Fig. 1. In the following description, the illustrated top-bottom direction in the front view of Fig. 1 will also be referred to as the height direction, the illustrated left-right direction will also be referred to as the width direction, and the illustrated top-bottom direction in the plan view will also be referred to as the depth direction.

[0009] The iron core 2 is composed of two annular sub-cores 2a arranged adjacent to each other in the width direction, and a main core 2b arranged on the outer periphery of the sub-cores 2a. The sub-cores 2a and the main core 2b are formed by winding a band-shaped material such as a silicon steel plate or an amorphous alloy. The iron core 2 has a so-called three-legged structure, and a coil 3 is attached to each leg 2c. However, the configuration of the iron core 2 shown here is only an example, and the number of legs and the outer shape may be different. Hereinafter, the direction along the legs 2c of the iron core 2 is referred to as the axial direction.

[0010] As shown in a plan view, each coil 3 is arranged concentrically around the leg 2c, and is composed of an inner coil 4 arranged on the inner side and an outer coil 5 arranged on the outer side. In this embodiment, the inner coil 4 is a low-voltage coil on the relatively low voltage side, and the outer coil 5 is a high-voltage coil on the relatively high voltage side.

[0011] The inner coil 4 is formed by winding a sheet-like conductor so as to have a generally annular shape as a whole in a plan view as shown in Fig. 2. More specifically, the inner coil 4 is formed in a generally rectangular tubular shape having two long side flat portions 10 that are flat on the inner or outer side and are arranged opposite each other with the leg portion 2c in between, two short side flat portions 11 that are flat on the inner or outer side and are arranged opposite each other with the leg portion 2c in between, and four corner portions 12A, 12B, 12C, and 12D that connect the ends of the long side flat portions 10 and the short side flat portions 11.

[0012] In this embodiment, the inner coil 4 is formed in a shape that is symmetrical on the left and right, and the leg portion 2c passes through the central space. Furthermore, the inner coil 4 has gaps between the sheet-like conductors of the short-side flat portion 11. The total thickness of the sheet-like conductors of the short-side flat portion 11 is also D10.

[0013] In this embodiment, one gap is provided in the short-side flat portion 11 on the upper side in the figure, and two gaps are provided in the short-side flat portion 11 on the lower side in the figure. In addition, gaps are also formed between the short-side flat portion 11 and the leg portion 2c. These gaps penetrate the inner circumferential coil 4 in the axial direction, and also function as flow paths for the flow of refrigerant such as air. In addition, in this embodiment, the flat portion is a portion where either the inner circumferential side or the outer circumferential side is flat, but the flat portion may be a portion where both the outer circumferential side and the inner circumferential side are flat, and when the lengths of the flat portion differ between the outer circumferential side and the inner circumferential side, the positions serving as the reference for the horizontal distance and vertical distance described below may be different between the outer circumferential side and the inner circumferential side.

[0014] If the direction of these corners 12 from top to bottom in the figure along the long-side flat portion 10 is defined as the vertical direction and the direction of the corners 12 from left to right in the figure along the short-side flat portion 11 is defined as the horizontal direction, the horizontal distance from the long-side flat portion 10 to the end of the short-side flat portion 11 is different from the vertical distance from the end of the long-side flat portion 10 to the short-side flat portion 11. The shapes of the corners 12 will be described below, but because the inner circumference side coil 4 is formed symmetrically, corner 12C has a shape obtained by mirror-mirroring corner 12A, and corner 12D has a shape obtained by mirror-mirroring corner 12B, detailed description of corners 12C and 12D will be omitted.

[0015] Corner 12A is formed in an irregular shape such that the horizontal distance (X10) from the long-side flat portion 10 to the end of short-side flat portion 11 is longer than the vertical distance (Y10) from the end of long-side flat portion 10 to short-side flat portion 11 on its outer periphery. Corner 12A is formed in an irregular shape such that the horizontal distance (X11) from the long-side flat portion 10 to the end of short-side flat portion 11 is longer than the vertical distance (Y11) from the end of long-side flat portion 10 to short-side flat portion 11 on its inner periphery. Corner 12C, which is symmetrical to corner 12A, is also formed in a similar shape.

[0016] On the other hand, the corner 12B is formed in an irregular shape such that the horizontal distance (X12) from the long-side flat portion 10 to the end of the short-side flat portion 11 is longer than the vertical distance (Y12) from the end of the long-side flat portion 10 to the short-side flat portion 11 on its outer periphery. Also, the corner 12B is formed in an irregular shape such that the horizontal distance (X13) from the long-side flat portion 10 to the end of the short-side flat portion 11 is longer than the vertical distance (Y13) from the end of the long-side flat portion 10 to the short-side flat portion 11 on its inner periphery. Also, the corner 12D, which is symmetrical to the corner 12B, is formed in a similar shape.

[0017] That is, at least the outer periphery side of the corners 12 of the inner periphery side coil 4 is formed in an irregular shape, and in this embodiment, the inner periphery side is also formed in an irregular shape. In addition, in this embodiment, the outer periphery side of each corner 12 is formed in a curved shape on the side closer to the long side flat portion 10 and in a flat shape on the side closer to the short side flat portion 11, and the inner periphery side is formed in a generally flat shape from the long side flat portion 10 to the short side flat portion 11. However, the shape of the corners 12 shown here is just an example, and other shapes are possible.

[0018] On the other hand, the outer coil 5 is generally formed in an annular shape as a whole in a plan view as shown in FIG. 3. In the present embodiment, the outer coil 5 is a so-called molded coil in which an annular conductor is stacked in the axial direction and molded with a resin material to be generally formed in a rectangular tubular shape as a whole. The outer coil 5 has two long side flat parts 20 that are flat on the inner or outer side and are arranged opposite to each other with the leg part 2c in between, two short side flat parts 21 that are flat on the inner or outer side and are arranged opposite to each other with the leg part 2c in between, and four corner parts 22A, 22B, 22C, and 22D that connect the end of the long side flat part 20 and the end of the short side flat part 21, and is formed in a bilaterally symmetrical shape.

[0019] The long side flat portion 20 is molded to have a thickness of D20. If the direction from top to bottom along the long side flat portion 20 is the vertical direction and the direction from left to right along the short side flat portion 21 is the horizontal direction, the corner portion 22A is formed in an irregular shape on its outer periphery such that the horizontal distance (X20) from the long side flat portion 20 to the end of the short side flat portion 21 is longer than the vertical distance (Y20) from the end of the long side flat portion 20 to the short side flat portion 21. The corner portion 22A is formed in an irregular shape on its inner periphery such that the horizontal distance (X21) from the long side flat portion 20 to the end of the short side flat portion 21 is shorter than the vertical distance (Y21) from the end of the long side flat portion 20 to the short side flat portion 21. That is, the corner portion 22A of the outer periphery coil 5 is formed in an irregular shape on both the inner periphery and the outer periphery. Moreover, corner portion 22C, which is symmetrical to corner portion 22A, is formed in the same shape.

[0020] On the other hand, the corner 22B is formed in an irregular shape on its inner periphery such that the horizontal distance (X22) from the long side flat portion 20 to the short side flat portion 21 is approximately equal to but slightly longer than the vertical distance (Y22) from the end of the long side flat portion 20 to the short side flat portion 21. The corner 22B is connected to an external connection portion 7 having a terminal 6 such as a primary terminal or a tap terminal shown in FIG. 1 and a lead wire (not shown) connected to the annular conductor embedded therein. Therefore, the outer periphery of the corner 22B is formed in an irregular shape such that the vertical distance (Y23) from the end of the long side flat portion 20 to the short side flat portion 21 is longer than the horizontal distance (X23) from the long side flat portion 20 to the end of the short side flat portion 21. The corner 22D, which is symmetrical to the corner 22B, is also formed in a similar shape.

[0021] That is, the corners 22 of the outer coil 5 are formed in different shapes on both the inner and outer sides. In addition, the corners 22A and 22C of the outer coil 5 are formed in a flat shape on the outer side, close to the long side flat portion 20 and close to the short side flat portion 21, respectively, and are formed in a shape in which the two flat portions are connected, and on the inner side, the corners 22A and 22C of the outer coil 5 are formed in a flat shape on the outer side, close to the long side flat portion 20 and close to the short side flat portion 21, respectively, and are formed in a shape in which the two flat portions are connected. In addition, the corners 22B and 22D of the outer coil 5 are formed in a flat shape on both the outer side and inner side, close to the long side flat portion 20 and close to the short side flat portion 21, respectively, and are formed in a shape in which the two flat portions are connected. However, the shape of the corners 22 shown here is an example, and other shapes, such as a curved portion, may be used.

[0022] Next, the operation and effects of the above-mentioned configuration will be described. As shown in Fig. 4, the conventional coil 104 as a comparative example is formed into a ring shape by winding a conductor, but it is necessary to increase the thickness in order to increase the capacity. However, if the bending radius of the corners 112 is made small when winding the conductor, gaps may occur between the conductors or the conductors may bend, which may cause the conductors to be wound without being in close contact with each other, resulting in a bulging state. Conventionally, the bending radius has been made large to prevent the bulging, which results in an increase in the outer size and an increase in the circumferential length, which is the length of one revolution of the conductor in the ring-shaped portion, resulting in an increase in loss.

[0023] In contrast, as shown in the comparative example, in the case of the inner coil 4, the corners 12 are made irregular in shape, which makes it possible to bring the conductors into close contact without increasing the bending radius. Also, by forming gaps between the conductors in the short side flat portion 11, it becomes possible to further suppress winding swelling. And, by making the corners 12 irregular in shape, it is possible to make the outer shape smaller than that of the conventional coil 104, and since the circumferential length is shorter, it is possible to suppress losses.

[0024] 5, conventional molded coil 105 as a comparative example has corners 22 with a constant curvature to match the outer shape of conventional coil 104, which leads to an increase in the outer shape. In contrast, as shown in a comparative example, corners 22 of outer periphery side coil 5 have a different shape to match the shape of inner periphery side coil 4, which makes it possible to make the outer shape smaller than that of conventional molded coil 105. Also, at corners 22B and 22D where external connection part 7 is provided, it is possible to reduce the outer shape while ensuring the size required for external connection part 7.

[0025] According to the embodiment described above, the following effects can be obtained. The stationary induction device 1 includes an iron core 2 and a coil 3 that is formed into a ring shape as a whole by winding a conductor and is attached to the iron core 2. When viewed from the axial direction, the coil 3, in the case of the inner coil 4, has a long side flat portion 10 that is flat on the inner or outer side and is arranged opposite to each other with the leg portion 2c in between, a short side flat portion 11 that is arranged opposite to each other with the leg portion 2c in between, and a plurality of corners 12 that connect the long side flat portion 10 and the short side flat portion 11. At least one corner 12 is formed in an irregular shape in which, when the direction along the long side flat portion 10 is the vertical direction and the direction along the short side flat portion 11 is the horizontal direction, the horizontal distance from the long side flat portion 10 to the end of the short side flat portion 11 is different from the vertical distance from the end of the long side flat portion 10 to the short side flat portion 11.

[0026] With this configuration, it is possible to suppress the winding swelling without increasing the bending radius of the conductor, making it possible to reduce the size and shorten the circumferential length, thereby achieving low loss. The same effect can also be obtained with the outer coil 5 formed with the same purpose.

[0027] In addition, when viewed from the axial direction, the coil 3 is formed in an annular shape as a whole, having a long-side flat portion 10, which is flat on the inner or outer circumferential side and is arranged opposite to each other with the leg portion 2c therebetween, a short-side flat portion 11, which is arranged opposite to each other with the leg portion 2c therebetween, and a plurality of corners 12 connecting the long-side flat portion 10 and the short-side flat portion 11, and at least one corner 12 is formed in an irregular shape in which the horizontal distance from the long-side flat portion 10 to the end of the short-side flat portion 11 and the vertical distance from the end of the long-side flat portion 10 to the short-side flat portion 11 are different, can also provide the same effect as the stationary induction device 1 described above. In addition, the same effect can be obtained whether the inner circumferential coil 4 or the outer circumferential coil 5 is viewed alone or whether they are arranged concentrically.

[0028] Furthermore, in the stationary induction device 1, the coil 3 has an inner coil 4 arranged on the concentric inner side and an outer coil 5 arranged on the outer side of the inner coil 4, and the inner coil 4 has an irregular shape on the outer side of the corner 12, and the outer coil 5 has an irregular shape on the inner side of the corner 12. This allows the coil 3 to be made smaller overall, even when the inner coil 4 and the outer coil 5 are arranged concentrically.

[0029] Moreover, by forming both the inner and outer circumferential sides of corners 12 and 22 into irregular shapes as in this embodiment, it is possible to further shorten the circumferential length and further suppress loss. Also, by forming corners 12 and 22 into irregular shapes by one or more flat surfaces, one or more curved surfaces, or a combination of one or more flat surfaces and one or more curved surfaces, it is possible to improve the degree of freedom in designing the outer edge, inner edge, or overall shape of coil 3.

[0030] As shown in Fig. 6, the inner circumferential surface of the corners 22A, 22B, 22C, and 22D is formed by combining two planar portions. In the case of Fig. 6, the inner circumferential surface of the corner 22C is formed by combining the inner circumferential surface 22Ca on the long side flat portion 20 side and the inner circumferential surface 22Cb on the short side flat portion 21 side. The inner circumferential surface of the corner 22D is formed by combining the inner circumferential surface 22Da on the long side flat portion 20 side and the inner circumferential surface 22Db on the short side flat portion 21 side. The corner 22A has a symmetrical shape to the corner 22C, and the corner 22B has a symmetrical shape to the corner 22D.

[0031] In addition, if the intersection of the long side flat portion 20 and the inner peripheral surface 22Ca in the corner portion 22C is PC1, the intersection of the inner peripheral surface 22Ca and the inner peripheral surface 22Cb is PC2, and the intersection of the inner peripheral surface 22Cb and the short side flat portion 21 is PC3, the vertical distance (ΔL1) between the intersection points PC1 and PC2 in a plan view can be formed shorter than the vertical distance (ΔL2) between the intersection points PC1 and PC2. Also, the horizontal distance (ΔL3) between the intersection points PC1 and PC2 can be formed shorter than the horizontal distance (ΔL4) between the intersection points PC1 and PC2. Also, the width (LCa) of the inner peripheral surface 22Ca can be formed shorter than the width (LCb) of the inner peripheral surface 22Cb.

[0032] In addition, in the corner 22D, the intersection point between the long side flat portion 20 and the inner peripheral surface 22Da is PD1, the intersection point between the inner peripheral surface 22Da and the inner peripheral surface 22Db is PD2, and the intersection point between the inner peripheral surface 22Db and the short side flat portion 21 is PD3. In a plan view, the vertical distance (ΔL11) between the intersection points PD1 and PD2 can be formed shorter than the vertical distance (ΔL12) between the intersection points PD1 and PD2. In addition, the horizontal distance (ΔL13) between the intersection points PD1 and PD2 can be formed shorter than the horizontal distance (ΔL14) between the intersection points PD1 and PD2. In addition, the width (LDa) of the inner peripheral surface 22Da can be formed shorter than the width (LDb) of the inner peripheral surface 22Db.

[0033] Even with this shape, it is possible to provide a space between the short side flat portion 21 and the inner circumference side coil 4 arranged on its inner side at the upper side in the figure, and as shown in Fig. 7 described later, by providing an intermediate lead, the position of the corner does not change much, but the outer circumference side coil 5 of the same shape can be used for the inner circumference side coil 4A which is longer in the upper direction in the figure. In other words, by making the vertical distance of the inner circumference surface different, it is possible to optimize the dimension between the inner circumference side coil 4. Also, at the lower side in the figure, the shape is irregular according to the outer shape of the inner circumference side coil 4, and there is no excessive gap, so the stationary induction device 1 can be made smaller and lighter overall.

[0034] In this embodiment, the inner circumferential surface 22Ca and the inner circumferential surface 22Da are formed in a flat shape and are parallel to the apex of the corner of the inner circumferential coil 4. Furthermore, the width (LCa) of the inner circumferential surface 22Ca and the width (LDa) of the inner circumferential surface 22Da are set to a length that allows placement of a cushioning material 8, which will be described later. Note that the example dimensions shown in FIG. 6 are merely examples and are not limited to these. For example, if the corner has an irregular shape overall, the width (LCa) of the inner circumferential surface 22Ca and the width (LDa) of the inner circumferential surface 22Da may be configured to match each other.

[0035] As described above, the outer coil 5 of this embodiment is a molded coil. Such a molded coil is formed by placing a conductor in a mold and filling the mold with a molding material such as epoxy resin, and therefore the outer shape of the molded coil is determined by the mold.

[0036] In the case of a stationary induction device 1 having an inner coil 4 and an outer coil 5, it is assumed that the outer shape of the inner coil 4 varies depending on the specifications. Specifically, as shown as an example in Fig. 7, the inner coil 4 has a gap for intermediate lead-out on the short side flat portion 11 on the upper side in the figure. Since this gap is formed between the sheet-like conductors, the depth (H1) of the inner coil 4 is larger than the depth (H2) of the inner coil 4 without intermediate lead-out. The intermediate lead-out is a terminal for taking out a so-called intermediate potential from between the winding start end and winding end end of the sheet-like conductor.

[0037] In this case, preparing a mold individually according to the specifications of the inner circumference side coil 4 would increase the number of parts and the number of work processes, and is therefore considered undesirable in terms of both manufacturing management and cost. Therefore, in this embodiment, the outer circumference side coil 5 is formed so that at least the inner circumference side of the corner portion 22 has a different shape, and is formed to a size that allows the inner circumference side coil 4 with a different outer shape to be arranged therein.

[0038] 8 shows a state in which the inner coil 4 is arranged in a conventional molded coil 105, and comparative example 2 shows a state in which the inner coil 4 is arranged in a conventional molded coil 105 of the same shape that can accommodate the inner coil 4. Moreover, example 1 shows a state in which the inner coil 4 is arranged in an outer coil 5, and comparative example 2 shows a state in which the inner coil 4 is arranged in an outer coil 5 of the same shape that can accommodate the inner coil 4.

[0039] In the case of Comparative Example 1, since conventional molded coil 105 is not an irregular shape, larger gaps (G1 to G4) than necessary are formed at the four corners between the inner circumference coil 4. In the case of Comparative Example 2, in addition to the four corners, a larger gap (G5) than necessary is formed between conventional molded coil 105 and short side flat portion 11 on the upper side in the figure.

[0040] In contrast, in the case of Example 1, the outer coil 5 is made to have a different shape, so that a necessary gap is formed between it and the inner coil 4, and even in the case of Example 2, the gap (G10) between the inner coil 4 and the outer coil 5 is prevented from becoming excessively large. In addition, since the shape is such that the necessary size is secured on the side where the intermediate outlet is provided, there is no difference in the region (R1) on the lower side in the figure between Example 1 and Example 2. Therefore, the center lines (CL) of the central opening of the inner coil 4 through which the leg 2c passes are aligned with each other.

[0041] This prevents the coils 3 and therefore the stationary induction device 1 from becoming larger, and since the relative positional relationship of each coil 3 to the iron core 2 does not change, and since the outer coils 5 are formed in the same shape, even if the specifications of the inner coils 4 are different, the support structure, the arrangement of the support members, and the external shape of the stationary induction device 1 can be standardized, which is extremely advantageous from both a manufacturing and cost perspective.

[0042] Also, as shown in Fig. 9, a cushioning material 8 may be provided between the inner circumference side coil 4 and the outer circumference side coil 5. Furthermore, spacers 9 may be arranged in the gaps formed in the short side flat portion 11 and between the inner circumference side coil 4 and the leg portion 2c. This prevents the inner circumference side coil 4 and the outer circumference side coil 5 from coming into contact with each other and the gaps formed in the inner circumference side coil 4 from being crushed during assembly, transportation, or operation. Note that the arrangement and number of the cushioning material 8 and the spacers 9 shown in Fig. 9 are merely examples, and the arrangement and number may be changed.

[0043] Furthermore, the external connection part 7 is a so-called high-voltage side terminal, and it is necessary to ensure a creepage distance between it and the inner circumference side coil 4. At this time, if the cushion material 8 is placed near the external connection part 7, it becomes difficult to ensure the creepage distance due to the presence of the cushion material 8. In other words, the area between the inner circumference side coil 4 and the outer circumference side coil 5 on the external connection part 7 side is a weak point in terms of ensuring insulation, and it is preferable not to place the cushion material 8 in this area.

[0044] However, in the case of the conventional configuration, as shown in Comparative Examples 1 and 2 in Figure 8, there is no flat portion at the corner between the inner coil 4 and the outer coil 5, so in order to place the cushion material 8 at the corner in the conventional configuration, it was necessary to devise or process the shape of the cushion material 8.

[0045] In contrast, the inner circumferential surface 22Ca and the inner circumferential surface 22Da of the outer circumferential coil 5 are formed flat and parallel to the apexes of the corners of the inner circumferential coil 4, so that the cushioning material 8 can be placed at the corners without any processing, and there is no need to place the cushioning material 8 near the external connection portion 7, which ensures insulation, which is of great technical significance.

[0046] Furthermore, since the flat portion of the inner coil 4 is a portion that is less susceptible to tension, there is a possibility that the dimensional variation may become larger than that of the corners due to the occurrence of bulging of the coil. In addition, if the bulging occurs, the width of the flat portion will change, and since the intermediate lead is provided on the short side, the dimensional variation of that portion will also be large, so it becomes necessary to prepare cushioning material 8 of an appropriate size each time.

[0047] In contrast, the corners are areas where tension is applied and swelling does not occur, so there is little dimensional variation, and because no swelling occurs, they are strong and furthermore, even if an intermediate lead is added, there is little change in dimension. Therefore, a configuration that allows cushioning material 8 to be placed at the corners is extremely suitable for placing the cushioning material 8.

[0048] So far, the outer coil 5 has been described as a molded coil, but it may be a non-molded coil. Specifically, as shown in FIG. 10, the outer coil 5A is a so-called multi-coil configuration in which a strip-shaped conductor is wound in the width direction to a predetermined thickness (D30) and layered to obtain a required height in the axial direction. It may be a configuration in which an annular conductor having a predetermined thickness in the axial direction is layered to obtain a required height. The outer coil 5A has two long side flat parts 30 that are flat on the inner or outer side and are arranged opposite to each other with the leg part 2c in between, two short side flat parts 31 that are flat on the inner or outer side and are arranged opposite to each other with the leg part 2c in between, and four corner parts 32A, 32B, 32C, and 32D that connect the end of the long side flat part 30 and the end of the short side flat part 31, and is formed in a bilaterally symmetrical shape.

[0049] At this time, the corner 32A is formed in an irregular shape in which the horizontal distance (X30) is longer than the vertical distance (Y30) on the outer periphery side, and in which the horizontal distance (X31) is longer than the vertical distance (Y31) on the inner periphery side. The corner 32C, which is symmetrical to the corner 32A, is also formed in a similar shape. The corner 32B is formed in an irregular shape in which the horizontal distance (X32) is longer than the vertical distance (Y32) on the inner periphery side, and in which the vertical distance (Y33) is longer than the horizontal distance (X33) on the outer periphery side. The corner 32D, which is symmetrical to the corner 32B, is also formed in a similar shape.

[0050] In this way, by using an outer coil 5A that is not a molded coil, it is possible to reduce the size of the outer coil 5A, as with the inner coil 4 described in Figure 4 above, and it is also possible to shorten the circumferential length, thereby suppressing losses, and thereby obtaining the same effects as in the embodiment.

[0051] In addition, in the embodiment, a molded transformer is exemplified as the stationary induction device 1, but the configuration in which the inner circumferential coil 4 and the outer circumferential coil 5A are arranged as shown in Arrangement Example 1 in Fig. 11, or the configuration in which the inner circumferential coil 4A and the outer circumferential coil 5A are arranged as shown in Arrangement Example 2, may be used to target a transformer having an unmolded coil 3 such as an oil-filled transformer. Even with such a configuration, it is possible to prevent excessively large gaps from being formed between the four corners and the outer circumferential coil 5A, and as described in the above-mentioned Example 1 and Example 2 in Fig. 8, it is possible to prevent the coil 3 and the stationary induction device 1 from becoming large, and it is possible to obtain the same effects as those of the embodiment, such as the ability to standardize the arrangement of the support structure and support members, or the external shape of the stationary induction device 1.

[0052] In the embodiment, a configuration in which both the inner and outer circumferential sides of the corners have a different shape was exemplified, but for example, only the outer circumferential side of the inner coil 4 may be made a different shape, and only the inner circumferential side of the outer coil 5 may be made a different shape. That is, at least one corner may be made a different shape in which the horizontal distance from the long side flat portion to the end of the short side flat portion is different from the vertical distance from the end of the long side flat portion to the short side flat portion. With such a configuration, it is possible to obtain the same effects as the embodiment, such as miniaturization and shortening of the overall circumference.

[0053] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0054] In the drawings, 1 indicates a stationary induction device, 2 indicates an iron core, 3 indicates a coil, 4 indicates an inner coil, 5 indicates an outer coil, 8 indicates a cushioning material, 10, 20, and 30 indicate flat portions on the long sides, 11, 21, and 31 indicate flat portions on the short sides, and 12, 22, and 32 indicate corners.

Claims

1. Iron core and a coil formed into an annular shape by winding a conductor and attached to the iron core; When viewed from the axial direction along the iron core, the coil has long-side flat portions whose inner or outer circumferential sides are flat and which are arranged opposite each other with the leg portion in between, short-side flat portions which are arranged opposite each other with the leg portion in between, and a plurality of corners connecting the long-side flat portions and the short-side flat portions, At least one of the corner portions is formed in an irregular shape such that, when the direction along the long-side flat portion is the vertical direction and the direction along the short-side flat portion is the horizontal direction, the horizontal distance from the long-side flat portion to the end of the short-side flat portion and the vertical distance from the end of the long-side flat portion to the short-side flat portion are different.

2. The coil has an inner coil arranged on the inner periphery of the concentric shape, and an outer coil arranged on the outer periphery side of the inner coil, The inner coil has an outer circumferential side of the corner portion formed in an irregular shape, 2. The stationary induction device according to claim 1, wherein the inner circumferential side of the corner portion of the outer circumferential coil is formed in a non-uniform shape.

3. 3. The stationary induction device according to claim 2, wherein the outer coil is a molded coil.

4. The outer shape of the inner coil varies depending on the specifications.

4. The stationary induction device according to claim 2, wherein the outer circumferential coil is sized so that the inner circumferential coil having a different outer shape can be placed therein.

5. 2. The stationary inductor according to claim 1, wherein the corners are formed in an irregular shape by one or more flat surfaces, one or more curved surfaces, or a combination of one or more flat surfaces and one or more curved surfaces.

6. The stationary inductor according to claim 1 , further comprising a cushioning material disposed between the inner coil and the outer coil.

7. A coil mounted on an iron core of a stationary induction device, When viewed from the axial direction along the core, the core is generally formed in a ring shape having a long-side flat portion whose inner or outer circumferential side is flat and disposed opposite to each other across the leg portion, a short-side flat portion disposed opposite to each other across the leg portion, and a plurality of corners connecting the long-side flat portion and the short-side flat portion, A coil in which at least one of the corner portions is formed in an irregular shape such that, when the direction along the long-side flat portion is the vertical direction and the direction along the short-side flat portion is the horizontal direction, the horizontal distance from the long-side flat portion to the end of the short-side flat portion and the vertical distance from the end of the long-side flat portion to the short-side flat portion are different.

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