oil-filled transformer

Abstract

To provide an oil-immersed transformer with a simple structure that can suppress deformation. [Solution] The oil-filled transformer 1 according to the embodiment comprises a plurality of coils 2 composed of inner coils 12a and outer coils 12b arranged concentrically, an iron core 3 having legs 13 on which the coils 2 are mounted, an upper fitting 4 provided on the upper end side of the iron core 3, a lower fitting 5 provided on the lower end side of the iron core 3, and an inner circumferential support member 6 provided on the inner circumferential side of the coil 2 with its upper end supported by the upper fitting 4 and its lower end supported by the lower fitting 5, and which supports the coil 2 from the inner circumferential side and suppresses deformation by distributing and transmitting the mechanical force generated in the coil 2 to the upper fitting 4 and the lower fitting 5, wherein the upper end of the inner circumferential support member 6 is fixed to the upper fitting 4 in a range below the upper horizontal line (L10), and the lower end is fixed to the lower fitting 5 in a range above the lower horizontal line (L11).

Description

Technical Field

[0001] Embodiments of the present invention relate to oil-immersed transformers.

Background Art

[0002] An oil-immersed transformer includes a core and a plurality of-phase coils mounted on the core. The coils are generally composed of an inner peripheral coil and an outer peripheral coil arranged concentrically. In such an oil-immersed transformer, it is necessary to suppress deformation of the coils due to short-circuit mechanical forces generated during an external short circuit (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a short-circuit mechanical force occurs and the coils are deformed, there is a risk of interference with the coils of other phases, causing the phase interval to widen, or contact with the core, causing the core to deform. In addition, due to the repulsion between the inner peripheral coil and the outer peripheral coil, there is a risk of change in the gap provided between the inner peripheral coil and the outer peripheral coil (hereinafter referred to as the main gap).

[0005] In this case, adopting a strong structure to suppress the widening of the phase interval will lead to an increase in size and weight. If the core is deformed, the characteristics may deteriorate. If the main gap changes, there is a risk of an increase in the impedance change rate. Therefore, countermeasures against these are required.

[0006] Therefore, an oil-immersed transformer capable of suppressing deformation with a simple structure is provided.

Means for Solving the Problems

[0007] The oil-filled transformer according to this embodiment comprises a plurality of coils composed of inner and outer coils arranged concentrically, an iron core on which the coils are mounted, an upper fitting provided on the upper end of the iron core, a lower fitting provided on the lower end of the iron core, and a deformation suppressing member provided on the inner circumference of the coils with its upper end supported by the upper fitting and its lower end supported by the lower fitting, which supports the coils from the inner circumference and suppresses deformation by distributing and transmitting the force from the coils to the upper and lower fittings. The deformation suppressing member is supported by the upper fitting at its upper end in a range below a hypothetical upper horizontal line passing through the center of the upper corner of the iron core, and by the lower fitting at its lower end in a range above a hypothetical lower horizontal line passing through the center of the lower corner of the iron core. [Brief explanation of the drawing]

[0008] [Figure 1] This figure schematically shows an example configuration of an oil-immersed transformer according to the first embodiment. [Figure 2] A schematic diagram showing the cross-section of the coil and iron core. [Figure 3] A diagram illustrating the effects of coils of different shapes. [Figure 4] A schematic diagram showing an example of the configuration of the inner circumferential support member. [Figure 5] A schematic diagram showing the support configuration of the inner circumferential support member. [Figure 6] Diagram illustrating the effects of the inner circumferential support member. [Figure 7] This figure schematically shows an example configuration of an oil-immersed transformer according to the second embodiment. [Figure 8] This diagram illustrates the effects of the first and second plate-shaped members. [Figure 9] A schematic diagram showing the support configuration of the first plate-shaped member. [Figure 10] This figure schematically shows an example configuration of an oil-immersed transformer according to the third embodiment. [Figure 11] This figure schematically shows an example configuration of an oil-immersed transformer according to the fourth embodiment. [Figure 12] Diagram illustrating the effects of reinforcing members. [Figure 13] This figure schematically shows an example configuration of an oil-immersed transformer according to the fifth embodiment. [Modes for carrying out the invention]

[0009] Several embodiments will be described below with reference to the drawings. Parts that are substantially common to each embodiment will be denoted by the same reference numerals, and their detailed descriptions will be omitted.

[0010] (First Embodiment) As shown in Figure 1, the oil-filled transformer 1 according to this embodiment comprises a plurality of coils 2, an iron core 3 on which the coils 2 are mounted, an upper fitting 4 that supports the upper end of the iron core 3, a lower fitting 5 that supports the lower end of the iron core 3, and an inner circumference support member 6 which corresponds to the deformation suppression member in this embodiment and supports the coils 2 from the inner circumference. These components are housed in a tank (not shown), and the tank is filled with cooling oil. Note that in Figure 1, the upper fitting 4 and the lower fitting 5 are shown with dashed lines for clarity.

[0011] In this embodiment, the iron core 3 is formed by laminating silicon steel plates and has three legs 13 with a rectangular cross-section. Coil 2A is attached to the leftmost leg 13, coil 2B is attached to the center leg 13, and coil 2C is attached to the rightmost leg 13. Hereafter, in common explanations, they will simply be referred to as coil 2 without the designations A to C. Note that the shape and size of coil 2 and iron core 3 shown in Figure 1 are examples. Also, illustrations of support structures for supporting coil 2 have been omitted.

[0012] The upper fitting 4 is formed in a hollow rectangular parallelepiped shape with an open bottom surface, and as shown in Fig. 2(a), it is arranged so that the bottom surface side covers the upper end of the iron core 3. Although not shown in the figure, a terminal block or the like connected to the coil 2 is provided on the upper fitting 4. On the other hand, the lower fitting 5 is formed in a hollow rectangular parallelepiped shape with an open top surface, and as shown in Fig. 2(b), it is arranged so that the top surface side covers the lower end of the iron core 3. The lower fitting 5 is fixed to the bottom surface of the tank and supports the iron core 3 from the lower end side.

[0013] As shown in the cross-sectional view taken along line IIb-IIb in Fig. 2(b), the coil 2 is composed of an inner peripheral coil 12a and an outer peripheral coil 12b arranged concentrically. A gap with a predetermined interval is provided between the inner peripheral coil 12a and the outer peripheral coil 12b. Hereinafter, the gap between the inner peripheral coil 12a and the outer peripheral coil 12b is referred to as the main gap (G. See Fig. 3).

[0014] In addition, in the present embodiment, for the coils 2A and 2C arranged at both ends among the three coils 2, those with irregular shapes in which the outer peripheral surfaces on the left and right in the figure bulge outward are adopted. Note that the coil 2C is arranged in the reverse direction of the same shape as the coil 2A. Hereinafter, the electromagnetic force generated during an external short circuit is referred to as the short-circuit mechanical force.

[0015] As will be described below, the irregular-shaped coil 2A can suppress the deformation when the short-circuit mechanical force is generated by its own shape. As shown as an example in Fig. 3, the short-circuit mechanical force is generated in a direction perpendicular to the surface of the coil 2A as indicated by the white arrow. At this time, in the longitudinal range (R1) of the coil 2A, the directions of the generated short-circuit mechanical forces become uneven.

[0016] In contrast, for the conventional coil 102 shown as a comparative example in FIG. 3, the short-circuit mechanical force generated in the longitudinal range (R2) is in a state where its direction coincides with the left direction in the figure. As a result, in the case of the conventional coil 102, the force attempting to deform it to the left in the figure is relatively larger compared to the case of the coil 2A of the embodiment. Also, although a main gap is provided between the conventional inner peripheral coil 102a and the conventional outer peripheral coil 102b, when a repulsive force occurs between them, the force in the left direction in the figure also becomes relatively larger.

[0017] Therefore, the amount of change (Δd2) in the position of the outer edge when a short-circuit mechanical force is generated in the conventional coil 102 is larger than the amount of change (Δd1) in the position of the outer edge when a short-circuit mechanical force is generated in the coil 2A. That is, the coil 2A of a different shape can suppress deformation by itself due to its shape.

[0018] In this embodiment, a configuration in which both the inner peripheral side coil 12a and the outer peripheral side coil 12b have different shapes is illustrated, but only the outer peripheral side coil 12b can have a different shape. Also, such a coil 2 with a different shape can be formed, for example, by winding while giving a bulge during winding of the conductor or by appropriately arranging an insulating member between the conductors and then winding.

[0019] As shown in FIG. 4(a), the inner peripheral side support member 6 includes a plate-like portion 61 extending in the vertical direction, and the upper end 62 of the plate-like portion 61 is supported by being fixed to the upper fitting 4. Also, the inner peripheral side arbitrary j member 6 is supported by the lower end 63 of the plate-like portion 61 being fixed to the lower fitting 5. In the case of this embodiment, the inner peripheral side support member 6 is formed of a steel plate.

[0020] As shown in Figures 1 and 2(b), the inner circumference support member 6 has a plate-shaped portion 61 that is inserted between the leg portion 13 on the inner circumference side of the coil 2. Also, as shown in Figure 2(a), the upper end fixing portion 62 and the end of the plate-shaped portion 61 of the inner circumference support member 6 are fixed to the inner surface of the upper fitting 4. Furthermore, as shown in Figure 2(c), the inner circumference support member 6 is positioned outside the coil 2A and outside the coil 2C with the lower end fixing portion 63 and the end of the plate-shaped portion 61 fixed to the inner surface of the lower fitting 5.

[0021] As shown in Figure 5, the inner circumference support member 6 is fixed to the inner surface of the side wall 4a of the upper fitting 4 in a range below a hypothetical upper horizontal line (L10) that passes through the center of the upper corner of the core 3. This upper horizontal line (L10) is a horizontal line parallel to the top edge of the core 3, passing through the intersection point (P10) where a hypothetical line inclined 45° to the left in the figure with respect to the center of curvature of the corner of the core 3 intersects with the outer surface of the core 3. The upper horizontal line (L10) can also be simply defined as a horizontal line passing through the center between the inner and outer surfaces of the coil 2. Although not shown in the figure, an inner circumference support member 6 positioned to the right of the core 3 is also fixed to the upper fitting 4 in a similar configuration.

[0022] Furthermore, the lower end 63 of the inner circumference support member 6 is fixed to the inner surface of the side wall 5a of the lower fitting 5 in a range above a hypothetical lower horizontal line (L11) that passes through the center of the lower corner of the iron core 3. This lower horizontal line (L10) is a horizontal line parallel to the lower edge of the iron core 3, passing through the intersection point (P11) where a hypothetical line inclined 45° to the left in the diagram with respect to the center of curvature of the corner of the iron core 3 intersects with the outer surface of the iron core 3. Note that the lower horizontal line (L11) can also be simply defined as a horizontal line passing through the center of the inner and outer surfaces of the coil 2. Although not shown in the diagram, the lower end 63 of the inner circumference support member 6, which is located on the right side of the iron core 3, is also fixed to the lower fitting 5 in a similar configuration.

[0023] In this configuration, the inner circumferential support member 6 is welded or bolted to the inner surface of the side wall 4a of the upper fitting 4 at its upper end, and welded or bolted to the inner surface of the side wall 5a of the lower fitting 5 at its lower end. This reduces the vertical length between the parts supported by the inner circumferential support member 6, that is, the vertical length of the parts that may bend. As a result, the amount of deflection of the inner circumferential support member 6 when pressed by the coil 2 or the iron core 3 is reduced, and deformation of the coil 2 and the iron core 3 can be suppressed by supporting the coil 2 from the inner circumferential side.

[0024] Furthermore, the side wall 4a of the upper fitting 4 is a high-strength area because it is on the shorter side of the upper fitting 4. By supporting the inner circumferential support member 6 with this high-strength area, movement of the inner circumferential support member 6 itself can be suppressed.

[0025] Note that the shape of the inner circumferential support member 6 shown in Figure 4(a) is just one example, and other shapes are possible. For example, a structure with increased rigidity can be created by bending the plate-like portion 61, as shown in Figure 4(b) for the inner circumferential support member 6A. Alternatively, a structure with increased rigidity can be created by providing a wall portion 64 at the end of the plate-like portion 61, as shown in Figure 4(c) for the inner circumferential support member 6B, and making the cross-section L-shaped, as will be shown in Figure 12 later.

[0026] Furthermore, a structure with increased rigidity can be achieved by providing wall portions 64 at both ends of the plate-shaped portion 61, as shown in Figure 4(d) for the inner circumferential support member 6C, and by making the cross-section U-shaped, as will be shown in Figure 13 later. The wall portions 64 are formed to a length that faces at least the inner circumferential area of ​​the coil 2 when the coil 2 is mounted on the iron core 3. However, the wall portions 64 can also be made relatively short to create a beam-like structure aimed at preventing deflection of the plate-shaped portion 61.

[0027] Next, the operation and effects of the above-described configuration will be explained. Figure 6(a) schematically illustrates the various forces acting on coil 2 using arrows. For example, a repulsive force may occur between the inner coil 12a and the outer coil 12b, as indicated by the arrows. Additionally, coil 2 may experience a pressing force from other coils 2, indicated by the dashed lines, as indicated by the arrows. Furthermore, coil 2 may deform due to the short-circuit mechanical force generated during an external short circuit.

[0028] When repulsive force, compressive force, or short-circuit mechanical force occurs, the main gap inside the coil 2 widens, the iron core 3 is compressed and deformed, the distance between phases (L1) widens, and the overall outer shape (L2) of each coil 2 widens. As a result, as mentioned above, this may lead to deterioration of characteristics and an increase in the impedance change rate. The distance between phases (L1) is the distance between the centers of adjacent coils 2, that is, roughly the distance between the centers of adjacent legs 13.

[0029] On the other hand, providing a robust structure to suppress deformation and positional changes of coil 2 would lead to an increase in the size and weight of the oil-filled transformer 1. Therefore, in this embodiment, deformation and positional changes of coil 2 and iron core 3 are suppressed with a simple structure.

[0030] Specifically, in this embodiment, the oil-filled transformer 1 has inner circumference support members 6 on the inner circumference side of the coils 2 located at both ends. Therefore, as shown in the embodiment in Figure 6(b), even if a repulsive force or pressing force is generated and the inner circumference side of the coil 2 deforms to the right in the figure and tries to push the iron core 3, that force is transmitted to the upper fitting 4 and the lower fitting 5 by the inner circumference support members 6 and is absorbed.

[0031] As a result, deformation and positional changes of the coil 2 and the legs 13 of the iron core 3 are suppressed. For example, the movement of the iron core 3 to the right in the figure is suppressed compared to the comparative example. As a result, the distance to the upper fitting 4 (W1) when deformation is suppressed by the inner circumference support member 6 is greater than the distance (W11) when the inner circumference support member 6 is absent, as shown in the comparative example. Furthermore, since the deformation of the iron core 3 is suppressed, the risk of deterioration of characteristics is reduced.

[0032] Furthermore, the deformation of the iron core 3 is suppressed by the inner circumferential support member 6, thereby suppressing deformation of the inner surface of the coil 2 and changes in its position to the right in the diagram. At this time, the deformation and position changes of the coil 2 are suppressed directly by the iron core 3 and indirectly by the inner circumferential support member 6. As a result, the width of the main gap of the coil 2 (W2) becomes smaller than the width of the main gap (W12) in the comparative example. This suppresses the increase in the impedance change rate.

[0033] Furthermore, the inner circumferential support member 6 suppresses changes in the position of the coil 2, thereby suppressing the expansion between phases. As a result, the distance (W3) from the inner circumferential surface of the upper fitting 4 to the outer edge of the coil 2 becomes smaller than the distance (W13) to the outer edge in the comparative example. In this way, the movement of the coil 2 itself is suppressed, and the expansion of the outer shape (L2) is suppressed to a smaller extent than when the inner circumferential support member 6 is not present.

[0034] According to the embodiments described above, the following effects can be obtained. The oil-filled transformer 1 according to this embodiment comprises a plurality of coils 2 composed of inner coils 12a and outer coils 12b arranged concentrically; an iron core 3 having legs 13 on which the coils 2 are mounted; an upper fitting 4 provided on the upper end side of the iron core 3; a lower fitting 5 provided on the lower end side of the iron core 3; and an inner support member 6 provided on the inner circumference side of the coil 2 with its upper end supported by the upper fitting 4 and its lower end supported by the lower fitting 5, which acts as a deformation suppressing member that supports the coil 2 from the inner circumference side and suppresses deformation by distributing and transmitting the mechanical force generated in the coil 2 to the upper fitting 4 and the lower fitting 5.

[0035] As a result, the oil-filled transformer 1 can withstand short-circuit mechanical forces and pressing forces between the coils 2 with its robust upper fittings 4 and lower fittings 5, thereby suppressing deformation and displacement of the coils 2 and the iron core 3. Furthermore, the inner circumference support member 6 has a simple shape because its upper end is fixed to the robust upper fitting 4 and its lower end is fixed to the robust lower fitting 5, thus avoiding an excessive increase in weight. Therefore, deformation and positional changes of the coils 2 and iron core 3 can be suppressed with a simple structure.

[0036] Furthermore, the inner circumferential support member 6 is formed in an L-shape facing two faces of the leg portion 13, which has a rectangular cross-section, or in a U-shape facing three faces of the leg portion 13. This configuration improves the strength of the inner circumferential support member 6 itself and reduces the warping of the plate-like portion 61, thereby further suppressing deformation and positional movement.

[0037] Furthermore, although the embodiment illustrates a configuration using coils 2A and 2C of different shapes, it is also possible to use a configuration in which all coils 2 are of different shapes, or a configuration in which only coils 2 of the same shape are used.

[0038] (Second Embodiment) Figure 7(a) schematically shows the oil-immersed transformer 1A according to this embodiment. For the sake of simplicity, parts common to the first embodiment are shown with dashed lines in Figure 7(a).

[0039] The oil-filled transformer 1A comprises an iron core 3A on which the coil 2 is mounted, a first plate-shaped member 20 provided at a position corresponding to the leg portion 13 on which the coil 2 is mounted and corresponding to the deformation suppression member in this embodiment, and a second plate-shaped member 21 provided between the first plate-shaped member 20 above and below the coil 2. The material of the first plate-shaped member 20 and the second plate-shaped member 21 is not limited as long as they have sufficient strength to prevent excessive bending when a force is applied in the width direction, and can be made of resin material, steel plate, etc.

[0040] The iron core 3A is formed from amorphous material and is constructed by laminating the first iron core 22 and the second iron core 23 in the thickness direction, as shown in Figure 7(b). Note that the shape of the iron core 3A is just an example and is not limited thereto.

[0041] The first plate-shaped member 20 is formed to a length such that its upper end reaches the upper fitting 4 and its lower end reaches the bottom surface of the lower fitting 5. Furthermore, the first plate-shaped member 20 is formed to be wider than the leg portion 13 of the iron core 3A, and slightly narrower than the inner diameter of the coil 2. As a result, the outer ends of the first plate-shaped member 20 on the right and left sides of the illustration are in close contact with the inner wall surface of the upper fitting 4 or the lower fitting 5. Therefore, when the coil 2 or iron core 3 deforms, the side of the first plate-shaped member 20 will be supported by the upper fitting 4 and the lower fitting 5.

[0042] As shown in Figure 7(b), the first plate-shaped member 20 is sandwiched between the first core 22 and the second core 23, and is provided on the inner circumference side of each coil 2 as shown in Figure 7(a). Note that the first plate-shaped member 20 is only sandwiched between the first core 22 and the second core 23 and is not fixed to any other members.

[0043] The second plate-shaped member 21 has the same thickness as the first plate-shaped member 20 and is formed in a plate shape with a width approximately the same as the gap between adjacent first plate-shaped members 20. As shown in Figure 7(b), the second plate-shaped member 21 is sandwiched between the first core 22 and the second core 23, and is provided above and below each coil 2 as shown in Figure 7(a). The second plate-shaped member 21 is only sandwiched between the first core 22 and the second core 23 and is not fixed to any other members.

[0044] As shown in Figure 8(a), the first plate-shaped member 20 and the second plate-shaped member 21 are arranged so as to connect the walls of the upper fitting 4 and lower fitting 5 on the left and right sides of the diagram with virtually no gaps. Although only the central coil 2 is shown in Figure 8 for the sake of simplicity, the effects and advantages described below can also be obtained with the other coils 2.

[0045] As explained in the first embodiment, if a repulsive force, pressing force, or short-circuit mechanical force is generated in the coil 2, the coil 2 and the iron core 3 may deform, potentially leading to a deterioration of performance. Conversely, the more the deformation of the coil 2 and the iron core 3 can be suppressed, the more the deterioration of performance can be suppressed. Therefore, in this embodiment, as deformation suppression members, a first plate-shaped member 20 is provided on the inner circumference side of each coil 2 corresponding to the leg portion 13 of the iron core 3A, and a second plate-shaped member 21 is provided between each of the first plate-shaped members 20.

[0046] As shown in Figure 8(b), if, for example, the inner surface of coil 2 deforms to the right in the figure due to a repulsive force, the inner surface of coil 2 will come into contact with the first plate-shaped member 20, which has a width approximately equal to the inner diameter of coil 2. At this time, although a force is applied to the first plate-shaped member 20 pushing to the right in the figure, as also shown in Figure 8(c), a second plate-shaped member 21 is positioned to the side of the first plate-shaped member 20, and another first plate-shaped member 20 is positioned to the right of the second plate-shaped member 21 in the figure. The other first plate-shaped member 20 is positioned so as to be in contact with the inner wall surfaces of the upper fitting 4 and the lower fitting 5.

[0047] Therefore, even if a force from coil 2 is applied to the first plate-shaped member 20, that force is distributed by the upper second plate-shaped member 21 and transmitted to another first plate-shaped member 20, and then transmitted to and received by the upper fitting 4 and lower fitting 5 by that other first plate-shaped member 20. The first plate-shaped member 20 and the second plate-shaped member 21 are positioned with virtually no gap between the left and right inner wall surfaces of the upper fitting 4 and the lower fitting 5.

[0048] Therefore, even if force from the coil 2 is applied to the first plate-shaped member 20 and the second plate-shaped member 21, their movement to the right in the diagram will ultimately be restricted by the upper fitting 4 and the lower fitting 5. As a result, the coil 2 will not deform any further once its inner circumference contacts the first plate-shaped member 20, and the widening of the main gap will also be suppressed.

[0049] As shown in Figure 9, the first plate member 20 is in contact with the inner surface of the side wall 4a of the upper fitting 4 in a range below a hypothetical upper horizontal line (L20) that passes through the center of the upper corner of the core 3. This upper horizontal line (L20) is a horizontal line parallel to the top edge of the core 3, passing through the intersection point (P20) where a hypothetical line inclined 45° to the left in the figure with respect to the center of curvature of the corner of the core 3 intersects with the outer surface of the core 3. The upper horizontal line (L20) can also be simply defined as a horizontal line passing through the center between the inner and outer surfaces of the coil 2. Although not shown in the figure, the first plate member 20 located to the right of the core 3 is also fixed to the upper fitting 4 in a similar configuration.

[0050] Furthermore, the first plate member 20 is fixed to the inner surface of the side wall 5a of the lower fitting 5 in a range above a hypothetical lower horizontal line (L21) that passes through the center of the lower corner of the iron core 3. This lower horizontal line (L20) is a horizontal line parallel to the lower edge of the iron core 3, passing through the intersection point (P21) where a hypothetical line inclined 45° to the left in the diagram with respect to the center of curvature of the corner of the iron core 3 intersects with the outer surface of the iron core 3. For simplicity, it can also be defined as a horizontal line passing through the center of the inner and outer surfaces of the coil 2. Although not shown in the diagram, the lower end 63 of the first plate member 20, which is located on the right side of the iron core 3, is also fixed to the lower fitting 5 in a similar configuration.

[0051] In this configuration, the upper end of the first plate member 20 is in contact with the inner surface of the side wall 4a of the upper fitting 4, and the lower end is in contact with the inner surface of the side wall 5a of the lower fitting 5. This allows the vertical length of the non-contact portion of the first plate member 20 to be shortened. As a result, the amount of deflection of the first plate member 20 when pressed by the coil 2 and the iron core 3 is reduced, and deformation of the coil 2 and the iron core 3 can be suppressed by supporting the coil 2 from the inner circumference.

[0052] Furthermore, the side wall 4a of the upper fitting 4 is a high-strength part because it is on the shorter side of the upper fitting 4. By supporting the first plate member 20 with this high-strength part, movement of the first plate member 20 itself can be suppressed.

[0053] According to the embodiments described above, the following effects can be obtained. The oil-filled transformer 1A comprises an iron core 3A formed by stacking a first iron core 22 and a second iron core 23; a first plate-shaped member 20 provided on the inner circumference side of the coil 2, sandwiched between the first iron core 22 and the second iron core 23, with its upper end reaching the upper fitting 4 and its lower end reaching the lower fitting 5, distributing and transmitting the force from the coil 2 to the upper fitting 4 and the lower fitting 5; and a second plate-shaped member 21 provided between the first plate-shaped members 20 above and below the coil 2, sandwiched between the first iron core 22 and the second iron core 23, and transmitting the force from the first plate-shaped member 20 to other adjacent first plate-shaped members 20.

[0054] As a result, even if coil 2 attempts to deform, the deformation is suppressed by the first plate-shaped member 20, the second plate-shaped member 21, the upper fitting 4, and the lower fitting 5. In this case, since the first plate-shaped member 20 and the second plate-shaped member 21 are plate-shaped members, the structure does not become complicated. Therefore, deterioration of characteristics and increase in impedance change rate can be suppressed with a simple structure.

[0055] Furthermore, in the configuration in which the inner circumferential support member 6 shown in Figure 4 and the inner circumferential support members 6A to 6D shown in Figure 5 are provided, a first plate-shaped member 20 and a second plate-shaped member 21 can be further provided, and the first plate-shaped member 20 can be supported by the upper fitting 4 and the lower fitting 5 via the inner circumferential support member 6 and the inner circumferential support members 6A to 6D. In other words, the configuration of the second embodiment can be applied to the first embodiment and other embodiments.

[0056] (Third embodiment) The oil-filled transformer 1B shown in Figure 10(a) has a configuration that is generally the same as that of the first embodiment, but it is equipped with outer peripheral support members 30 that support the coils 2 from the sides, in this case, on the outside of the coils 2 at both ends. For explanatory purposes, parts common to the first embodiment are shown with dashed lines in Figure 10(a).

[0057] The outer peripheral support member 30 has a generally flat plate-like portion 31, an upper fixing portion 32 whose upper end is bent and fixed to the upper fitting 4, and a lower fixing portion 33 whose lower end is bent and fixed to the lower fitting 5. The upper fixing portion 32 and the lower fixing portion 33 are also provided with screw holes for fixing. The outer peripheral support member 30, with its central plate-like portion 31 in contact with the outer peripheral surface of the coil 2, suppresses deformation of the coil 2 that tends to spread outward and outward movement when pushed by other coils 2.

[0058] By providing such an outer peripheral support member 30, deformation and outward movement of the coil 2 are suppressed, thereby preventing deterioration of characteristics and an increase in the impedance change rate. Note that the shape of the outer peripheral support member 30 is just an example and is not limited thereto.

[0059] Furthermore, by making the coils 2A and 2C, which are positioned at both ends, different in shape as in this embodiment, it is possible to reduce the force applied to the outer peripheral support member 30 itself, thereby preventing the structure of the outer peripheral support member 30 from becoming excessively complex. As a result, the outer peripheral support member 30 itself can be made smaller and lighter. In addition, although not shown in the figures, it is also possible to provide the outer peripheral support member 30 to the oil-filled transformer 1A shown in Figure 7.

[0060] (Fourth Embodiment) The oil-filled transformer 1C shown in Figure 11(a) has a configuration that is generally the same as that of the first embodiment, but is equipped with a reinforcing member 40 on the inner circumference side of the central coil 2. For explanatory purposes, parts common to the first embodiment are indicated by dashed lines in Figure 11(a).

[0061] As shown in Figures 11(b) to (d), the reinforcing member 40 has a lower end supported by the bottom surface of the lower fitting 5, an upper end that extends at least above the upper end of the coil 2, and has two reinforcing plate-like portions 41 positioned on the front and rear sides of the leg portion 13 as shown, and a reinforcing connecting portion 42 that connects the two reinforcing plate-like portions 41 in a range that is at least on the inner circumference side of the coil 2.

[0062] As shown in Figure 12(a), the reinforcing member 40 has a U-shape in cross-section on the inner circumference side of the coil 2, with the cross-section facing the three surfaces of the leg portion 13. Furthermore, since the reinforcing plate-like portion 41 of the reinforcing member 40 is arranged along the left-right direction shown in the figure, the structure is particularly strong against deformation in the left-right direction shown in the figure.

[0063] Therefore, by providing the reinforcing member 40, when the coil 2 deforms as shown in the embodiment in Figure 12(b), the deformation on the inner circumference side is restricted by the reinforcing member 40, and the widening of the main gap (Δd40) becomes smaller than the widening (Δd41) in the case without the reinforcing member 40, as shown in the comparative example. In other words, by providing the reinforcing member 40, the widening of the main gap can be suppressed, and the increase in the impedance change rate can be effectively suppressed.

[0064] Furthermore, the provision of the inner circumferential support member 6 suppresses deformation of the coil 2, thereby preventing deterioration of its characteristics. Although Figure 12 illustrates a configuration with an inner circumferential support member 6C, other shapes of inner circumferential support members 6 may also be provided.

[0065] Furthermore, as shown in Figure 12(c), a reinforcing member 40A can be adopted, which consists of one reinforcing plate-like portion 41 and one reinforcing connecting portion 42, and is L-shaped, facing two surfaces of the leg portion 13 in the area that is on the inner circumference side of the coil 2. This configuration can also suppress the widening of the main gap. In addition, a configuration can be adopted in which an outer peripheral support member 30 is further provided.

[0066] (Fifth embodiment) The oil-filled transformer 1D shown in Figure 13(a) has a configuration that is generally the same as that of the first embodiment, but the inner circumference of the central coil 2 has been hardened. For explanatory purposes, parts common to the first embodiment are indicated by dashed lines in Figure 13(a).

[0067] This hardening treatment can be performed by, for example, forming a coating film 50 made of a resin material on the inner surface of the coil 2. By performing such a hardening treatment, deformation of the inner surface of the coil 2 can be suppressed, similar to Figure 12(b) above. In other words, by applying a hardening treatment to the inner surface of the coil 2, the widening of the main gap can be suppressed, and the increase in the impedance change rate can be effectively suppressed.

[0068] Furthermore, the provision of the inner circumferential support member 6 suppresses deformation of the coil 2, thereby preventing deterioration of its characteristics. In this embodiment, a configuration with an inner circumferential support member 6D is illustrated, but a configuration with an inner circumferential support member 6 of other shapes may also be used.

[0069] Furthermore, although this embodiment shows an example in which the inner surface of the centrally located coil 2B is hardened, it is also possible to configure the coil 2A and coil 2C to have their inner surfaces hardened. Also, although not shown in the figures, it is possible to configure the coil 2 to have its inner surface hardened on two or three surfaces facing the leg portion 13. Additionally, it is possible to further provide a reinforcing member 40 after the hardening treatment. Furthermore, it is also possible to configure the coil 2 of the oil-filled transformer 1A shown in Figure 7 to have its hardening treatment applied.

[0070] The configurations described in the first to fifth embodiments above can be combined as appropriate, provided there are no inhibiting factors.

[0071] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as described in the claims. [Explanation of Symbols]

[0072] In the drawing, 1, 1A to 1D are oil-filled transformers, 2, 2A to 2C are coils, 3, 3A are iron cores, 4 is upper fittings, 5 is lower fittings, 6, 6A to 6C are inner circumference support members, 12a is inner circumference coil, 12b is outer circumference coil, 13 is leg portion, 20 is first plate-shaped member, 21 is second plate-shaped member, 22 is first iron core, 23 is second iron core, 30 is outer circumference support member, and 40 and 40A are reinforcing members.

Claims

1. Multiple coils, each consisting of an inner coil and an outer coil arranged concentrically, The iron core on which the coil is mounted, The upper fitting provided on the upper end side of the iron core, The lower fitting provided on the lower end side of the iron core, The device comprises a deformation suppressing member provided on the inner circumference of the coil, with its upper end supported by the upper fitting and its lower end supported by the lower fitting, which supports the coil from the inner circumference and suppresses deformation by distributing and transmitting the force from the coil to the upper and lower fittings, An oil-filled transformer wherein the deformation-suppressing member is supported by the upper fitting at the upper end in a range below a hypothetical upper horizontal line passing through the center of the upper corner of the iron core, and is supported by the lower fitting at the lower end in a range above a hypothetical lower horizontal line passing through the center of the lower corner of the iron core.

2. The first plate-shaped member is provided on the inner circumference of the coil, sandwiched between the first core and the second core, and is formed to a length such that its upper end reaches the upper fitting and its lower end reaches the lower fitting, and distributes and transmits the force from the coil to the upper fitting and the lower fitting, and the first plate-shaped member is provided as the deformation suppressing member, The coil comprises a second plate-shaped member provided between the first plate-shaped members above and below the coil, sandwiched between the first iron core and the second iron core, and transmitting force from the first plate-shaped member to an adjacent first plate-shaped member, An oil-filled transformer in which the first plate-shaped member contacts the upper fitting at its upper end in a range below a hypothetical upper horizontal line passing through the center of the upper corner of the iron core, and contacts the lower fitting at its lower end in a range above a hypothetical lower horizontal line passing through the center of the lower corner of the iron core.

3. The oil-filled transformer according to claim 1 or 2, further comprising an outer peripheral support member provided on the side of the coil and supporting the coil from the outer peripheral side.

4. The oil-filled transformer according to claim 1 or 2, further comprising a reinforcing member provided on the inner circumference side of the coil and having a rectangular cross-section, which is L-shaped and facing two faces of the legs of the iron core, or U-shaped and facing three faces of the legs of the iron core.

5. The oil-filled transformer according to claim 1, wherein the inner circumferential support member is formed in an L-shape facing two faces of the legs of the iron core, which has a rectangular cross-section, or in a U-shape facing three faces of the legs of the iron core.

6. The oil-immersed transformer according to claim 1 or 2, wherein at least one of the coils has been hardened on its inner surface.

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