JP2015192140A - Transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to adjust the effective length of a connection bolt, which connects a transformer body and the lid of a tank, outside the tank without decreasing fixing strength for the transformer body within the tank.SOLUTION: A connection bolt 31 connecting a transformer body 20 and the lid 12 of a tank 10 are spirally engaged with a seat-plate-having nut 35, with its seat plate part 35b facing down. The nut body 35a of the seat-plate-having nut is loosely passed through a through-hole 12a provided in the lid, and guided out upward from the lid. The nut body 35a is operated from outside the tank 10, and the position of the nut 35 in the direction of height is adjusted, thereby adjusting the effective length of the connection bolt. A bag nut 37 is spirally engaged with the projection of the connection bolt 31, projecting upward from the upper end of the seat-plate-having nut, and the seat-plate-having nut 35 is accommodated in the bag nut. The bag nut 37 is tightened against the lid 12 of the tank 10 via a packing 38, thereby sealing the bag nut 37 from inside and outside.

Description

  The present invention relates to a transformer in which a transformer body is accommodated in a tank.

  The transformer is housed with an insulating medium in a tank having a bottomed tank body having an opening at the upper end and a lid fixed to the upper end of the tank body to close the opening of the tank body. It is constituted by doing. In this type of transformer, in order to prevent the transformer body from moving in the tank and to prevent the formation of a dent that accumulates rainwater on the upper surface of the tank lid, a connecting bolt is used between the transformer body and the lid. By connecting and causing the connecting bolt to serve as a tension rod, the transformer body is pressed against the bottom plate of the tank and fixed to the bottom plate, and the lid is appropriately inflated upward.

  6 and 7 show an example of this type of conventional transformer. FIG. 6 is a front view showing a state in which the lid is connected to the transformer body via a connecting bolt when the transformer body is accommodated in the tank, and FIG. 7 is a cross-sectional view of the lid. It is the longitudinal cross-sectional view which showed the state which accommodated the transformer main body in the tank and attached the lid | cover to the tank main body.

  In FIG. 7, 1 is a tank comprising a bottomed tank body 101 and a lid 102 that closes the opening at the upper end of the tank body, and 2 is that upper and lower yoke parts are fastened by core fasteners 201a and 201b, respectively. The transformer body includes a three-leg iron core 202 and three-phase windings 203u, 203v, and 203w wound around three legs of the iron core 202, respectively. In this example, at least a pair of nuts 3 and 3 are fixed to the lower surface of the lid 102 of the tank by welding or the like with a gap in the direction in which the three-phase windings 203u to 203w of the transformer body 2 are arranged side by side. Screw portions at the upper ends of the pair of connecting bolts 4 and 4 fixed to the transformer body 2 are screwed into the nuts 3 and 3. In the example shown in FIG. 7, the connecting bolts 4, 4 are stud bolts (bolts that do not have a head and are provided with screws at least at both ends), and each lower end is transformed by nuts 5 and 6. It is fastened to a core fastener 201a that fastens the upper yoke portion of the iron core 202 of the main body 2 of the machine.

  When the transformer body is housed in the tank and the transformer is assembled, the lid 102 is connected to the transformer body 2 before being housed in the tank via the connecting bolts 4 and 4 as shown in FIG. In the state, the lid 102 and the transformer body 2 are lifted, the transformer body 2 is inserted into the tank body 101 as shown in FIG. 7, and the lid 102 is placed on the upper end of the tank body 101 via the packing P. The lid 102 is fixed to the tank body 101 by appropriate means.

  As shown in FIG. 7, with the transformer body 2 housed in the tank 1 and the lid 102 fixed to the tank body 101, the connecting bolts 4 and 4 are made to function as tension rods, and the transformer body 2 By pushing the lid 102 downward and upward, respectively, the lower end of the transformer body 2 is pressed against the bottom plate 101a of the tank body and fixed, and the lid 102 is appropriately inflated upward, so that rainwater collects on the upper surface of the lid 102. The formation of the dent is prevented.

  6 and 7, the lower end of the transformer body 2 is pressed against the bottom plate of the tank body to prevent the transformer body from moving in the tank and to form an appropriate bulge in the lid 102. In addition, it is necessary to adjust the height position of the connecting bolts 4 and 4 to accurately adjust the effective length of the connecting bolts 4 and 4 as the tension rod. The effective lengths of the connecting bolts 4 and 4 are adjusted based on the measured depth of the tank body 101 and the measured height of the transformer body before inserting the transformer body into the tank body. After the effective length of the connecting bolt 4 is adjusted, the transformer body 2 is actually accommodated in the tank, and the degree of swelling of the lid 102 is observed. In many cases, this adjustment does not have to be performed once, and it is necessary to perform an operation of raising and lowering the heavy transformer body 2 together with the lid 102 every time adjustment is performed.

  In the structure shown in FIGS. 6 and 7, in the unlikely event that the effective length of the connecting bolts 4 and 4 is insufficient, the lower end of the transformer body 2 may be pressed against the bottom plate of the tank body with sufficient pressing force and fixed. Since there is a possibility that it cannot be performed, it is essential to fix the metal fitting 7 for securing the transformer body 2 to the bottom plate 101 a of the tank body 101.

  Therefore, as shown in Patent Literature 1, a transformer content fixing structure has been proposed that enables adjustment of the effective length of the connecting bolt (effective length as a tension rod) from the outside of the lid. FIG. 8 shows the content fixing structure 8 of the transformer disclosed in Patent Document 1. In the content fixing structure shown in FIG. 8, a tubular portion 801 a in which a female screw portion and a male screw portion are formed on the inner periphery and the outer periphery, respectively, and tool engaging grooves 801 c and 801 c are formed on the outer periphery of the tip portion. And a special nut 801 having a washer portion 801b integrally formed at the lower end of the tubular portion, and an internal thread portion of the tubular portion 801a of the special nut 801 is screwed into the connecting bolt 4. Then, the connecting bolt 4 and the tubular portion 801a of the special nut 801 screwed into the connecting bolt are passed through the hole 102a provided in the tank lid 102 and led out above the lid 102.

  After the lid 102 was fixed to the upper end of the tank body (not shown in FIG. 8), the lid 102 was engaged with parallel grooves 801c and 801c formed at the upper end of the tubular portion 801a of the special nut 801 protruding from the lid 102. By rotating the special nut 801 with a tool and adjusting the height direction position of the washer portion 801b of the special nut 801, the effective length of the connecting bolt 4 as a tension rod is adjusted. Next, after the washer 803 is fitted to the tubular portion 801a of the special nut 801, the lock nut 802 is screwed onto the male screw portion on the outer periphery of the special nut tubular portion 801a, and the lock nut is tightened. The nut 801 is fastened to the lid 102.

JP-A-11-283842

  According to the content fixing structure of the transformer shown in FIG. 8, the tool is engaged with the grooves 801c and 801c of the tubular portion 801a of the special nut 801, and the special nut 801 is rotated from the outside of the tank to be connected. The effective length of the bolt 4 as a tension rod can be adjusted. Therefore, since it is not necessary to raise and lower the heavy transformer main body many times, the transformer can be easily assembled.

  However, in order to realize the content fixing structure shown in FIG. 8, a nut having a special structure integrally including a tubular portion having a female screw portion and a male screw portion on the inner periphery and outer periphery and a washer portion is provided. Since it needs to be manufactured, it is inevitable that the cost required to configure the connecting portion between the connecting bolt 4 that connects the transformer body and the tank lid and the tank lid 102 is increased.

  Further, in the case of the content fixing structure shown in FIG. 8, since the seal between the connecting bolt 4 and the female screw portion of the special nut 801 cannot be achieved, the female screw of the connecting bolt 4 and the special nut 801 is not provided. It was inevitable that rainwater invaded through the area. Therefore, the content fixing structure shown in FIG. 8 has a problem that it cannot be applied to a transformer installed outdoors.

  In the case of the content fixing structure shown in FIG. 8, since the breathing is performed between the inside of the transformer tank and the outside air through the connecting bolt 4 and the female screw portion of the special nut 801, the inside of the tank The insulating medium could not be sealed, and the insulating medium could be deteriorated by oxygen that entered the tank from the outside.

  Further, in the case of the structure shown in FIG. 8, when vibration is applied to the transformer during transportation of the transformer, the insulating oil in the tank leaks from the joint between the connecting bolt 4 and the special nut 801. Since there is a risk, the transformer cannot be transported in the factory filled with insulating oil, and it is necessary to perform the work of filling the insulating oil at the site where the transformer is installed, which is troublesome.

  Further, in the structure shown in FIG. 8, since it is necessary to screw the nut 802 into the male screw portion on the outer periphery of the tubular portion 801a of the special nut 801, the outer diameter of the tubular portion 801a of the special nut 801 is increased. It is difficult to give the special nut sufficient strength, and if the operating force applied to the special nut 801 from the tool engaged with the grooves 801c and 801c is too strong, the special nut 801 may be damaged. There is a problem that it is difficult to press the transformer body against the bottom plate of the tank with a sufficient pressing force, and it is difficult to reliably fix the transformer body in the tank.

  Further, in the case of the structure shown in FIG. 8, the connection bolt 4 is locked to the special screw 801 simply by screwing the upper end of the connection bolt 4 into the female screw portion of the special screw 801. Therefore, in the unlikely event that the connecting portion between the connecting bolt 4 and the transformer body is loosened and a rotational force is applied to the connecting bolt 4 due to vibration or the like, the relative position between the connecting bolt 4 and the special nut 802 is relatively small. As a result, the rotational displacement of the connecting bolt 4 and the special nut 802 may be loosened, which may reduce the fixing strength of the transformer body.

  The purpose of the present invention is to enable adjustment of the effective length as a tension rod of a connecting bolt that connects a tank lid and a transformer body without using a nut having a special structure from the outside of the tank, The fixing strength of the transformer body in the tank can be made sufficiently high, and the joint between the connecting bolt and the tank lid can be made to be an airtight and liquid tight structure. It is to provide a transformer that solves the problem.

  According to the present invention, a transformer body is housed together with an insulating medium in a tank having a bottomed tank body having an opening at the upper end and a lid fixed to the upper end of the tank body and closing the opening of the tank body. The transformer is supported in a state where the transformer body is placed on the bottom plate of the tank body. In the transformer targeted by the present invention, a plurality of connecting bolts having a lower end fixed to the transformer main body and a portion near the upper end fixed to the lid are provided, and the transformer main body is formed by stretching the plurality of connecting bolts. Is fixed in the tank.

  In the present invention, in order to achieve the above object, a nut main body having an axial dimension larger than the thickness of the tank lid, and an outer diameter larger than the nut main body in the axial direction of the nut main body. A nut with a seat plate having a seat plate portion integrated at one end is screwed to a screw portion near the upper end of each connecting bolt with the seat plate portion facing downward.

  In the present invention, the nut body of the nut with a seat plate is loosely penetrated, but a through hole having an inner diameter large enough to prevent passage of the seat plate portion is provided in the lid corresponding to each connection bolt. The nut body of the nut with the seat plate screwed to the bolt is arranged in a state of passing through the corresponding through hole provided in the lid, and the seat plate portion of the nut with the seat plate penetrates on the inner surface side of the lid The nut with the seat plate is tightened against the lid until it comes into contact with (is assigned to) the peripheral portion of the hole and the amount of swelling upward of the lid reaches the set swelling amount.

  Further, in the present invention, in a state in which each seat plate nut is tightened against the lid, the protruding portion protruding upward from the upper end of the nut screwed to each connecting bolt to the thread portion near the upper end of each connecting bolt is provided. The length of each connecting bolt is set to be formed, and a cap nut is screwed into the protruding portion of each connecting bolt, and the nut with a seat plate screwed into each connecting bolt is moved upward from the lid of the nut body The portion protruding to the inside is accommodated inside the cap nut. In addition, a packing is disposed between the lower end of each cap nut and the lid of the tank, and each cap nut is tightened against the periphery of the through-hole of the cap via the packing, The inside is sealed against the outside.

  According to the present invention, a nut with a seat plate integrally having a nut body and a seat plate portion is screwed to each connection bolt with the seat plate portion being down, and is screwed to each connection bolt. Since the nut body of the nut with a seat plate and the portion near the upper end of each connecting bolt penetrated the through hole provided in the tank lid loosely and led out upward from the tank lid, it protruded above the tank lid By adjusting the height direction position of the nut with the seat plate by rotating the nut with the seat plate by engaging the spanner with the nut body, the effective length of the connecting bolt (the effective length as the tension bar) is adjusted. be able to. Thus, according to the present invention, by operating the nut with a seat plate from the outside of the tank, the effective length of the connecting bolt that connects the transformer body and the lid of the tank can be adjusted. Therefore, the adjustment of the swelling of the lid of the tank and the adjustment of the fixing strength of the transformer main body in the tank can be accurately performed without repeatedly raising and lowering the transformer main body.

  The nut with a seat plate used in the present invention has a structure that is not much different from the nut with a flange generally used widely, and is manufactured at a lower cost than the special nut used in the prior art shown in FIG. Therefore, a mechanism for adjusting the effective length of the connecting bolt from the outside can be configured at a low cost.

  Further, in the present invention, since the connecting bolt and the tank lid are coupled using a nut with a seat plate that can be operated with a tightening tool such as a spanner, the nut of the transformer body in the tank is sufficiently tightened. Fixing strength can be increased.

  In the present invention, a cap nut having a space for accommodating a nut body of a nut with a seat plate is screwed into a protruding portion of a connecting bolt projecting upward from an upper end of the nut with a seat plate. In addition to a structure that tightens, a packing is interposed between the cap nut and the tank lid so that the cap nut is tightened against the tank lid via the packing. The connecting portion between the connecting bolt and the lid to be connected can be formed into an airtight and liquid tight structure. Therefore, the present invention can be applied to a transformer installed outdoors, and can also be applied to a transformer that needs to completely seal a tank.

  In the present invention, the connection bolt can be locked by tightening the cap nut screwed to the protruding portion of the connection bolt protruding upward from the nut with the seat plate. When the tightening part with the main body is loose and rotational torque acts on the connecting bolt due to electromagnetic vibration of the transformer, the height position of the nut with the seat plate changes, and the fixing strength of the transformer main body decreases. It is possible to prevent the lid from bulging and rain water from collecting on the top surface of the lid.

It is the front view which showed the external appearance of one Embodiment of the transformer which concerns on this invention. It is a longitudinal cross-sectional view of the transformer shown in FIG. It is the side view which showed the main body of the transformer shown in FIG. 1, and the connecting bolt fastened by this main body. It is sectional drawing which showed in detail the structure of the coupling | bond part of the connection bolt used in embodiment of FIG.1 and FIG.2 and the lid | cover of a tank. In embodiment of this invention, it is the front view which showed the state which screwed and fastened the nut to the connection bolt. In the conventional transformer, it is the front view which showed the state which connected the lid of the tank via the connecting bolt to the transformer main part, and showed the lid in cross section. It is a longitudinal cross-sectional view of the conventional transformer. It is sectional drawing which showed the structure of the principal part of the transformer content fixing structure shown by patent document 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5. 1 and 2 schematically show an overall configuration of an embodiment of a transformer according to the present invention. In these drawings, 10 is a tank of the transformer, and 20 is insulated in the tank 10. A transformer main body 30 accommodated together with oil (not shown) is a transformer main body fixing device for fixing the transformer main body 20 to the tank 10.

  More specifically, the tank 10 includes a tank body 11 having a side wall portion 11a and a bottom plate 11b and having an opening at the upper end, and a lid 12 for closing the opening at the upper end of the tank body 11. A heat sink 13 is attached to the side wall 11 a of the main body 11. The heat sink 13 is made of, for example, a corrugated plate, and is attached to the side wall 11a of the tank body by welding. In FIGS. 1 and 2, the detailed structure of the heat sink 13 is not shown. A radiator having an oil passage inside may be attached to the side wall of the tank body in place of the pressure release plate. The side wall 11a of the tank itself is formed into a corrugated shape and functions as a radiator on the side wall. There is also a case to have.

  On the upper part of the side wall portion of the tank body 11, a hanging ear 14 for hooking a hook of a lifting device such as a hoist crane when the transformer is lifted is welded. A leg 15 made of an angle material or the like is welded to the lower surface of the bottom plate 11b of the tank body 11.

  Although the configuration of the transformer main body housed in the tank 10 is arbitrary, the transformer main body 20 used in this embodiment includes a three-leg iron core 23 in which upper and lower yoke portions are fastened by core fasteners 21 and 22, respectively. And three-phase windings 25u, 25v and 25w wound around the three leg portions of the iron core 23, respectively. The transformer body 20 is inserted into the tank body 11 and placed on the bottom plate 11b of the tank body.

  The transformer fixing device 30 includes a plurality of connecting bolts 31 whose lower ends are fixed to the transformer body 20 and whose upper ends are fixed to the tank lid 12, and a coupling portion that couples the connecting bolts 31 to the tank lid 12. Is done. In the present embodiment, as shown in FIG. 3, a stud bolt is provided at one end in the longitudinal direction of each of the pair of core fasteners 21, 21 that fastens the upper yoke portion of the iron core 23 of the transformer body 20. Two connecting bolts 31 and 31 are arranged in a state where the iron core 23 is positioned at symmetrical positions on both sides of a vertical plane that bisects in the laminating direction of the steel plates, and the lower ends of the connecting bolts are nuts 32 and 33. Fastened to the core fasteners 21, 21. Similarly, the lower ends of two connecting bolts made of stud bolts are fastened to the other longitudinal end of each of the pair of core fasteners 21 and 21, and a total of four connecting bolts have their respective center axes. It is provided in a state of being positioned at four corners of a rectangle on a horizontal plane.

  The connecting bolt 31 may be provided so as to be able to stretch between the lid 12 and the transformer main body 20 in a well-balanced manner, and the number and arrangement of the connecting bolts are appropriately set according to the structure of the transformer main body. be able to. For example, when two connecting bolts can be fixed to one end side and the other end side of the iron core along a vertical plane that bisects the upper and lower yoke portions of the iron core of the transformer body in the width direction. These two connecting bolts can stretch between the lid 12 and the transformer body 20 in a well-balanced manner.

  In this embodiment, the connecting portion for connecting each connecting bolt 31 to the tank lid 12 is, as shown in FIG. 4, a nut 35 with a seat plate screwed into a portion near the upper end of the connecting bolt 31. And a cap nut 37 screwed into the connecting bolt 31 in a state where the nut 35 with a seat plate is housed inside.

  The nut 35 with a seat plate is integrated with a nut main body 35a having an axial dimension larger than the wall thickness of the tank lid 12, and an outer diameter larger than the nut main body 35a, and one end of the nut main body in the axial direction. The nut includes a seat plate portion 35b, and the nut is screwed into a portion near the upper end of each connecting bolt 31 with the seat plate portion 35b facing downward.

  The lid 12 is provided with a through-hole 12a having an inner diameter large enough to allow the nut body 35a of the nut 35 with a seat plate to pass through but not to allow the seat plate portion 35b to pass therethrough, corresponding to each connecting bolt 31. ing. In the illustrated example, the peripheral portion of the through hole 12a is deformed so as to have a convex shape upward (opposite to the tank body 11), and an annular seat portion 12b is formed in the peripheral portion of the through hole 12a. ing.

  The nut 35 with a seat plate screwed to each connecting bolt 31 is provided in a state in which the nut body 35a loosely (rotatably) penetrates the corresponding through hole 12a provided in the lid 12, and the seat plate The portion 35b is brought into contact with (applied to) the peripheral portion of the through hole 12a on the inner surface side of the lid 12 via a washer 36 made of a cushion material such as a press board. The nut 35 with a seat plate is attached to the lid until the amount of swelling upward of the lid 12 reaches a set swelling amount (set swelling amount) after the lid 12 is fixed to the upper end of the tank body 11 in the procedure described later. And tighten. The amount of swelling of the lid 12 can be confirmed by measuring the amount of upward displacement of a predetermined portion of the lid 12 (for example, the peripheral portion of the through hole 12a).

  In the present embodiment, the lower end of the transformer body 20 is used as the bottom plate of the tank body 11 while the nut 35 with a seat plate is tightened until the amount of swelling upward of the lid 12 reaches the set swelling amount. The set bulge amount of the lid 12 is set so that it can be pressed with a sufficient pressing force to fix it so as not to move.

  In this embodiment, when each seat plate nut 35 is tightened with respect to the lid 12 until the amount of swelling upward of the lid 12 reaches the set amount of swelling, as shown in FIG. The transformer body 20 of each connecting bolt is formed such that a protruding portion 31a having a height h protruding upward from the upper end of the nut 35 with a seat plate screwed to each connecting bolt is formed on the screw portion near the upper end of 31. The length of the portion extending upward is set, and the cap nut 37 is screwed into the protruding portion 31a of each connecting bolt 31 protruding from the upper end of the nut with the seat plate.

  The cap nut 37 includes a space 37 a that accommodates a portion of the nut body 35 a of the nut 35 with a seat plate that protrudes upward from the upper surface of the lid 12, and a female screw portion 37 b that is screwed into the protruding portion of the connecting bolt 31. When the cap nut 37 is screwed into the protruding portion 31a of each connecting bolt 31 and is tightened to the seat portion 12b of the lid 12, the nut body 35a of the nut 35 with a seat plate is provided. A portion protruding upward from the lid is accommodated inside the cap nut 37 and hidden.

  A packing accommodating groove is provided at the lower end of each cap nut 37, and a packing 38 is accommodated in the packing accommodating groove, and each cap nut 37 squeezes the packing 38 so that the through hole 12a of the lid is formed. The inside of each cap nut 37 is sealed with respect to the outside by the packing 38.

  The lid 12 of the tank 10 containing the transformer main body 20 includes high-voltage bushings 40u, 40v and 40w respectively connected to the U, V, W three-phase high-voltage side terminals of the transformer main body, and the three-phase transformer main body. A three-phase low-pressure bushing (not shown) connected to each low-voltage side terminal is attached.

  When assembling the above transformer, the lower ends of the connecting bolts 31 are fastened to the core fasteners 21 and 21 fastening the upper yoke portion of the iron core of the transformer body 20 using the nuts 32 and 33, After fixing the lower end of each connecting bolt to the transformer body, the transformer body 20 is inserted into the tank body 11, and the transformer body 20 is seated at a predetermined position on the bottom plate 11b of the tank body.

  When the lower ends of the connection bolts 31 are fixed to the transformer main body 20, the transformer main body 20 to which the lower ends of the connection bolts are fixed is accommodated in the tank main body in a later step, and the upper ends of the connection bolts Projecting upward from the lid 12 of the threaded portion of each connecting bolt when the close portion is projected upward from the lid through a corresponding through hole 12a provided in the lid 12 that closes the opening of the tank body. The measured height of the transformer main body 20 and the tank main body so that the length of the portion is within an allowable range to allow the cap nut 37 to be screwed and fully tightened. The length of the portion of each connecting bolt 31 that extends upward from the transformer body 20 is adjusted according to the measured height value. If the axial dimension of the space 37a of the cap nut 37 and the female threaded portion 37b is provided with a certain margin, the length of the portion protruding upward from the lid 12 of the threaded portion of each connecting bolt will vary somewhat. Even if it exists, since it does not interfere in the screwing to the protrusion part 31a of a cap nut, and the fastening with respect to the lid | cover 12, it is not necessary to perform said adjustment so strictly.

  When the length of the portion extending upward from the transformer body 20 of the screw portion of each connecting bolt 31 is always constant, the length of the portion protruding upward from the lid 12 of the screw portion of each connecting bolt is the transformer. It varies depending on the variation in the height dimension of the main body 20 and the variation in the height of the tank main body. Due to the variation in the height dimension of the transformer body 20 and the variation in the height of the tank body, the variation occurring in the length of the portion protruding upward from the lid 12 of the threaded portion of each connecting bolt will If it is possible to absorb the space 37a and the female thread portion 37b by providing a margin in the axial dimension, the adjustment work described above is omitted, and the length of the portion extending upward from the transformer body 20 is always set. It is also possible to fix the lower end of the connecting bolt to the transformer body so as to be constant.

  After fixing the lower end of each connecting bolt 31 to the transformer body 20 as described above, a nut 35 with a seat plate is placed on the screw portion near the upper end of each connecting bolt 31 and the seat plate portion 35b is placed downward. Then, the washer 36 is placed on the seat plate portion 35b of each nut 35 with a seat plate, and the lid 12 is placed on the upper end of the tank body 11. As shown in FIG. 2, packing P is interposed between the lid 12 and the upper end of the tank body 11. When the lid 12 is put on the upper end of the tank body 11, the nut body 35 a of the nut 35 with a seat plate screwed to each connection bolt 31 is inserted into the corresponding through hole 12 a provided in the lid 12, The nut main body 35a of the nut 35 with a seat plate passes through the through hole 12a. Next, the lid 12 is fastened to the upper end of the tank body 11 with a bolt (not shown), and the opening at the upper end of the tank body 11 is closed.

  After the lid 12 is attached to the upper end of the tank body 11 as described above, a nut tightening tool such as a spanner is applied to the portion of the nut body of the nut 35 with a seat plate that protrudes upward from the lid 12 through the through hole 12a. By engaging and rotating the nut 35 with a seat plate, the nut 35 with the seat plate is displaced upward, and the seat plate portion 35b of the nut with the seat plate is located on the inner surface side of the lid 12 and the peripheral portion of the through hole 12a. Are brought into contact with each other via a washer 36. In the state where the seat plate portion 35b of the nut with the seat plate is in contact with the peripheral portion of the through hole 12a, the nut 35 with the seat plate is further rotated, so that each connecting bolt 31 functions as a tension rod, and the lid 12 The transformer body 20 is pressed against the bottom plate 11 b of the tank body 11. Finally, the nut 35 with a seat plate is tightened against the lid until the amount of swelling upward of the lid 12 reaches the set swelling amount. As a result, the upper surface of the lid 12 has a predetermined bulge and the lower end of the transformer body 20 is pressed against the bottom plate 11b of the tank body with a sufficiently large pressing force so that the transformer body 20 does not move in the tank. .

  After tightening the nut 35 with a seat plate as described above, the cap nut 37 is attached to the protruding portion 31a of the connecting bolt protruding upward from the upper end of the nut 35 with the seat plate screwed to each connecting bolt 31. By screwing and fastening each cap nut 37 to the seat portion 12b around the through hole 12a of the lid 12 via a packing 38, gas and liquid can be exchanged between the inside and the outside of the cap nut 37. The inside of the cap nut 37 is sealed with respect to the outside so that there is no circulation. When the tightening of the nut 35 with the seat plate is completed, the height h of the protruding portion 31a of each connecting bolt 31 formed in a state of projecting upward from the upper end of the nut with the seat plate hinders the tightening of the cap nut 37. Set the height so as not to come.

  As described above, the transformer body is housed and fixed in the tank, and necessary parts such as bushings are attached to the lid 12 of the tank, and then the tank is inserted from an oil filling port (not shown) provided in the lid 12. Insulating oil is injected into 10.

  As described above, in the present embodiment, the nut 35 with a seat plate integrally including the nut main body 35a and the seat plate portion 35b is screwed to each connecting bolt 31 with the seat plate portion being down. Then, the nut body 35a of the nut with a seat plate screwed to each connecting bolt and the portion near the upper end of each connecting bolt 31 are loosely passed through the through hole provided in the tank lid 12, and upward from the lid 12. The nut body 35a led out and rotated upward from the lid 12 is rotated to adjust the height direction position of the nut with the seat plate. With this configuration, the effective length of the connecting bolt 31 (effective length as a tension rod) can be adjusted from the outside of the tank, so that the tank cover can be removed without repeatedly raising and lowering the transformer body. It is possible to accurately adjust the swelling of the transformer and the fixing strength of the transformer body in the tank.

  The nut 35 with a seat plate used in the present embodiment has a structure that is not greatly different from a generally used nut with a flange (or flange nut), and does not have a complicated structure. Compared to the special nut used in the prior art, it can be manufactured at a low cost. Also, since the nut 35 with a seat plate can have sufficient mechanical strength like a normal nut, the nut with the seat plate is sufficiently tightened so that the transformer body is firmly placed in the tank. Can be fixed.

  In this embodiment, the cap nut 37 having a space for accommodating the nut main body 35a of the nut 35 with a seat plate is screwed into the protruding portion 31a of the connecting bolt projecting upward from the upper end of the nut with the seat plate. Since the packing nut 38 is interposed between the cap nut 37 and the tank lid 12 so that the cap nut 37 is tightened against the tank lid via the packing 38, The connecting portion of the connecting bolt that connects the vessel main body 20 and the lid 12 of the tank 10 and the lid can be structured to be airtight and liquid tightly sealed. Therefore, the present invention can be applied to a transformer installed outdoors, and can also be applied to a transformer that needs to completely seal a tank. Further, since it is possible to prevent breathing through the connecting portion between the connecting bolt and the tank lid, it is possible to prevent the outside oil from entering the tank and deteriorating the insulating oil.

  In the transformer according to the present embodiment, the connecting bolt 31 can be locked by tightening the cap nut 37 screwed into the protruding portion 31a of the connecting bolt 31 protruding upward from the upper end of the nut 35 with a seat plate. For this reason, when the fastening portion between the lower end of the connection bolt 31 and the transformer body 20 is loosened for some reason, and rotational torque acts on the connection bolt 31 due to electromagnetic vibration of the transformer, It is possible to prevent the height position from changing and the fixing strength of the transformer body from being lowered, or the lid from bulging out and rain water from collecting on the top surface of the lid.

  In the present invention, when a stud bolt is used as a connecting bolt for connecting the transformer main body and the tank lid, the stud bolt may have a male screw portion over its entire length, a portion near one end, and the like. It may have a male screw portion only at the end portion. In order to appropriately adjust the length of the portion of the connecting bolt 31 that protrudes and extends upward from the transformer body, it is convenient to use a stud bolt as the connecting bolt, but the connecting bolt is not necessarily composed of the stud bolt. There is no need, and a bolt having a head at one end with which the tightening tool is engaged may be used as a connecting bolt, and one end of the connecting bolt may be fixed to the transformer body. In the above embodiment, the lower end of the connection bolt is fixed to the transformer body using a nut. However, the lower end of the connection bolt may be fixed to the transformer body by welding or the like.

  In the above embodiment, the transformer body 20 has a structure in which a three-phase winding is wound around a tripod laminated iron core in which upper and lower yoke portions are fastened with core fasteners. The present invention is merely an example, and the present invention connects the transformer main body and the tank lid with a connecting bolt regardless of the structure of the transformer main body. It can be widely applied to transformers that employ a structure in which the transformer body is pressed toward the bottom plate side of the tank by the tension and the lid of the tank is appropriately expanded upward.

  For example, in the above embodiment, a laminated core is used as an iron core around which a winding is wound. However, the present invention can also be applied when a wound core is used. Moreover, in the transformer to which the present invention is applied, the core tightening structure for tightening the yoke portion of the iron core is arbitrary, and the present invention can be applied even when the core portion is not tightened. The transformer main body accommodated in the tank may have an iron core and a winding wound around the iron core, and may have a portion that can fix the lower end of the connecting bolt. Of course, the present invention can be applied not only to a three-phase transformer but also to a single-phase transformer.

  In the above embodiment, the insulating oil is used as the insulating medium accommodated in the tank in order to insulate and cool the transformer. However, the present invention can also be applied when an insulating gas is used as the insulating medium. .

DESCRIPTION OF SYMBOLS 10 Tank 11 Tank main body 12 Tank lid 30 Transformer main body fixing device 31 Connecting bolt 32 Nut 33 Nut 35 Nut with a seat plate 35a Nut main body 35b Seat plate portion 36 Washer 37 Cap nut

Claims (1)

A transformer body is housed together with an insulating medium in a tank having a bottomed tank body having an opening at the upper end and a lid fixed to the upper end of the tank body and closing the opening of the tank body. A plurality of connecting bolts, each having a container body mounted on a bottom plate of the tank body, a lower end fixed to the transformer body, and a portion near the upper end fixed to the lid; In the transformer in which the transformer body is fixed in the tank by stretching,
A nut body having an axial dimension larger than a wall thickness of the tank lid; and a seat plate portion having an outer diameter larger than the nut body and integrated at one end of the nut body in the axial direction. A nut with a seat plate is screwed into the thread portion near the upper end of each connecting bolt with the seat plate portion facing down,
The nut body of the nut with the seat plate is loosely penetrated, but a through hole having an inner diameter large enough to prevent the passage of the seat plate portion is provided in the lid corresponding to each connecting bolt,
A nut body of a nut with a seat plate screwed to each connecting bolt is disposed in a state of passing through a corresponding through hole provided in the lid, and a seat plate portion of the nut with a seat plate is disposed on the lid. The nut with the seat plate is tightened with respect to the lid until the amount of bulging upward of the lid is abutted against the peripheral portion of the through-hole on the inner surface side,
In a state where each seat plate nut is tightened with respect to the lid, a protruding portion projecting upward from the upper end of the seat plate nut screwed to each connection bolt is located on the thread portion near the upper end of each connection bolt. The length of each connecting bolt is set to be formed,
A cap nut is screwed to the protruding portion of each connecting bolt, and a portion protruding upward from the lid of the nut body of the nut with a seat plate screwed to each connecting bolt is accommodated inside the cap nut.
A packing is disposed between the lower end of each cap nut and the lid of the tank, and each cap nut is tightened against the peripheral portion of the through hole of the lid via the packing,
The transformer characterized in that the inside of each cap nut is sealed from the outside by the packing.

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